ORCID Profile
0000-0003-1776-3429
Current Organisation
University of New South Wales
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Climate Change Processes | Atmospheric Sciences | Atmospheric Dynamics | Physical Geography and Environmental Geoscience | Physical Oceanography | Meteorology | Climatology (excl. Climate Change Processes) | Climate change processes | Surfacewater Hydrology | Natural Hazards | Environmental Engineering Modelling | Atmospheric dynamics | Photonics and Electro-Optical Engineering (excl. Communications) | Genetics | Cloud Physics | Physical oceanography | Genomics | Hydrology Not Elsewhere Classified | Water Resources Engineering | Soil Physics | Atmospheric sciences | Climate change science | Nanotechnology not elsewhere classified | Meteorology | Theoretical and Computational Chemistry not elsewhere classified | Forestry Fire Management | Atmospheric Sciences not elsewhere classified | Bioinformatics | Atmospheric Sciences Not Elsewhere Classified
ANZSRC Socio-Economic Objective (SEO)
Atmospheric Processes and Dynamics | Climate Change Models | Effects of Climate Change and Variability on Australia (excl. Social Impacts) | Expanding Knowledge in the Environmental Sciences | Climate Variability (excl. Social Impacts) | Natural Hazards in Forest and Woodlands Environments | Natural Hazards in Urban and Industrial Environments | Land and water management | Land and water management | Effects of Climate Change and Variability on New Zealand (excl. Social Impacts) | Land and water management | Water Allocation and Quantification | Natural Hazards in Mountain and High Country Environments | Expanding Knowledge in the Chemical Sciences | Expanding Knowledge in the Physical Sciences | Expanding Knowledge in the Information and Computing Sciences | Expanding Knowledge in the Biological Sciences |
Related Links
Publications
Detection, characterization, and persistence of Campylobacter hepaticus, the cause of spotty liver disease in layer hens
Publisher: Elsevier BV
Date: 07-2023
Hydrological impacts of climate change on inflows to Perth, Australia
Publisher: Springer Science and Business Media LLC
Date: 2002
Can Bias correction of regional climate model lateral boundary conditions improve low-frequency rainfall variability?
Publisher: American Meteorological Society
Date: 12-2017
Abstract: Global climate model simulations inherently contain multiple biases that, when used as boundary conditions for regional climate models, have the potential to produce poor downscaled simulations. Removing these biases before downscaling can potentially improve regional climate change impact assessment. In particular, reducing the low-frequency variability biases in atmospheric variables as well as modeled rainfall is important for hydrological impact assessment, predominantly for the improved simulation of floods and droughts. The impact of this bias in the lateral boundary conditions driving the dynamical downscaling has not been explored before. Here the use of three approaches for correcting the lateral boundary biases including mean, variance, and modification of s le moments through the use of a nested bias correction (NBC) method that corrects for low-frequency variability bias is investigated. These corrections are implemented at the 6-hourly time scale on the global climate model simulations to drive a regional climate model over the Australian Coordinated Regional Climate Downscaling Experiment (CORDEX) domain. The results show that the most substantial improvement in low-frequency variability after bias correction is obtained from modifying the mean field, with smaller changes attributed to the variance. Explicitly modifying monthly and annual lag-1 autocorrelations through NBC does not substantially improve low-frequency variability attributes of simulated precipitation in the regional model over a simpler mean bias correction. These results raise questions about the nature of bias correction techniques that are required to successfully gain improvement in regional climate model simulations and show that more complicated techniques do not necessarily lead to more skillful simulation.
Climate Change Significantly Alters Future Wildfire Mitigation Opportunities in Southeastern Australia
Publisher: American Geophysical Union (AGU)
Date: 31-07-2020
DOI: 10.1029/2020GL088893
Seasonal mean temperature changes control future heat waves
Publisher: American Geophysical Union (AGU)
Date: 16-07-2016
DOI: 10.1002/2016GL069408
Addressing the mischaracterization of extreme rainfall in regional climate model simulations – A synoptic pattern based bias correction approach
Publisher: Elsevier BV
Date: 2018
Amplification of Australian Heatwaves via Local Land‐Atmosphere Coupling
Publisher: American Geophysical Union (AGU)
Date: 20-11-2016
DOI: 10.1029/2019JD030665
Land surface albedo and vegetation feedbacks enhanced the millennium drought in south-east Australia
Publisher: Copernicus GmbH
Date: 24-01-2017
Abstract: Abstract. In this study, we have examined the ability of a regional climate model (RCM) to simulate the extended drought that occurred throughout the period of 2002 through 2007 in south-east Australia. In particular, the ability to reproduce the two drought peaks in 2002 and 2006 was investigated. Overall, the RCM was found to reproduce both the temporal and the spatial structure of the drought-related precipitation anomalies quite well, despite using climatological seasonal surface characteristics such as vegetation fraction and albedo. This result concurs with previous studies that found that about two-thirds of the precipitation decline can be attributed to the El Niño–Southern Oscillation (ENSO). Simulation experiments that allowed the vegetation fraction and albedo to vary as observed illustrated that the intensity of the drought was underestimated by about 10 % when using climatological surface characteristics. These results suggest that in terms of drought development, capturing the feedbacks related to vegetation and albedo changes may be as important as capturing the soil moisture–precipitation feedback. In order to improve our modelling of multi-year droughts, the challenge is to capture all these related surface changes simultaneously, and provide a comprehensive description of land surface–precipitation feedback during the droughts development.
The representation of health-relevant heatwave characteristics in a Regional Climate Model ensemble for New South Wales and the Australian Capital Territory, Australia
Publisher: Wiley
Date: 12-05-2017
DOI: 10.1002/JOC.4769
Reduced moisture sources contributed to the 2017-2019 southeast Australian drought
Publisher: Copernicus GmbH
Date: 15-05-2023
DOI: 10.5194/EGUSPHERE-EGU23-4681
Abstract: The Murray Darling Basin, located in southeast Australia, is an agriculturally rich area, providing one-third of the country& #8217 food supply. In 2017-2019 the region experienced one of its worst droughts since 1900. Rainfall in the Murray Darling Basin was consistently below average for three consecutive cool seasons, an unprecedented event on record. The drought set the extreme conditions that led later to the 2019-2020 Black Summer Bushfires. Previous studies suggest that the strong 2019 positive Indian Ocean Dipole intensified the conditions of the drought, however the state of the climate drivers cannot fully explain the onset and development of the Murray Darling Basin drought. In this study, we investigate processes other than remote climate drivers that may have triggered the drought. Using a Lagrangian model to backtrack moisture sources to southeast Australia, we show that local processes were crucial in explaining the onset and development of the drought. We identify the sources of moisture to the cool season precipitation over the Murray Darling Basin and show for the first time that the moisture supply from the Tasman Sea declined in 2017 and 2018. We further show that the expected moisture was instead transported northward by an anomalous anticyclonic circulation. Our results provide an explanation for the moisture and rainfall deficit that caused the 2017-19 drought. Understanding the processes that led to the 2017-2019 Murray Darling Basin drought is important for predicting and planning future multi-year droughts in Australia.
Diagnosing the seasonal land–atmosphere coupling strength over Northern Australia: dependence on soil moisture state and coupling strength definition
Publisher: Copernicus GmbH
Date: 19-09-2014
DOI: 10.5194/HESSD-11-10431-2014
Abstract: Abstract. The strength of land–atmosphere coupling during the onset (September) through to the peak (February) of the wet season over Northern Australia is statistically diagnosed using ensembles of land surface model simulations that produce a range of different background soil moisture states. We derive coupling strength between the soil moisture and the planetary boundary layer via a statistical measure of association. The simulated evaporative fraction and the boundary layer are shown to be strongly coupled during both SON and DJF despite the differing background soil moisture states between the two seasons as among the ensemble members. The sign and magnitude of the surface layer soil moisture based coupling strength during the onset of the wet season (SON) differs from the coupling between the evaporative fraction and boundary layer from the same season, and the coupling between the surface soil moisture and boundary layer coupling during DJF. The patterns and magnitude of the surface flux-boundary layer coupling are not captured when coupling is diagnosed using the surface layer soil moisture alone. The conflicting results arise because the surface layer soil moisture lacks strong association with the atmosphere during the monsoon onset because the evapotranspiration is dominated by transpiration. Our results indicate that accurately diagnosing coupling strength in seasonally dry regions, such as Northern Australia, requires root zone soil moisture to be included.
Correction: Comparative GO: A Web Application for Comparative Gene Ontology and Gene Ontology-Based Gene Selection in Bacteria
Publisher: Public Library of Science (PLoS)
Date: 17-04-2015
Hydroclimatic Variability and Predictability: A Survey of Recent Research
Publisher: Copernicus GmbH
Date: 15-03-2017
Abstract: Abstract. Recent research in large-scale hydroclimatic variability is surveyed, focusing on five topics: (i) variability in general, (ii) droughts, (iii) floods, (iv) land-atmosphere interactions, and (v) hydroclimatic prediction. Each surveyed topic is supplemented by illustrative ex les of recent research, as presented at a 2016 symposium honoring the career of Professor Eric Wood. Taken together, the recent literature and the illustrative ex les clearly show that research into hydroclimatic variability continues to be strong, vibrant, and multifaceted.
Impact of model structure and parameterization on Penman–Monteith type evaporation models
Publisher: Elsevier BV
Date: 06-2015
Australian climate extremes in the 21st century according to a regional climate model ensemble: Implications for health and agriculture
Publisher: Elsevier BV
Date: 06-2018
Modelling and evaluating the impacts of climate change on three major crops in south-eastern Australia using regional climate model simulations
Publisher: Springer Science and Business Media LLC
Date: 27-03-2019
Stable water isotope and surface heat flux simulation using ISOLSM: Evaluation against in-situ measurements
Publisher: Elsevier BV
Date: 04-2015
MODIS-derived boundary conditions for a mesoscale climate model: Application to irrigated agriculture in the Euphrates Basin
Publisher: American Meteorological Society
Date: 06-2005
DOI: 10.1175/MWR2947.1
Abstract: In arid and semiarid parts of the world, evaporation from irrigated fields may significantly influence humidity, near-surface winds, and precipitation. Using Moderate Resolution Imaging Spectroradiometer (MODIS) Terra imagery from summer and autumn 2000 the authors attempt to improve the realism of a regional climate model (the fifth-generation Pennsylvania State University–NCAR Mesoscale Model) with respect to irrigated agriculture. MODIS data were used to estimate spatially distributed vegetation fraction and to identify areas of irrigated land use. Additionally, a novel surface flux routine designed to simulate traditional flood irrigation was implemented. Together these modifications significantly improved model predictions of water flux and the surface energy balance when judged against independent weather station data and known crop requirements. Model estimates of watershed-level water consumption were more than doubled relative to simulations that did not incorporate MODIS data, and there were small but systematic differences in predicted temperature and humidity near the surface. The modified version of the mesoscale model also predicts the existence of heat-driven circulations around large irrigated features, and these circulations are similar in structure and magnitude to those predicted by linear theory. Based on these results, it was found that accurate representation of irrigated agriculture is a prerequisite to any study of the impact of land-use change on climate or on water resources.
Impact of identification method on the inferred characteristics and variability of Australian east coast lows
Publisher: American Meteorological Society
Date: 27-02-2015
Abstract: The Australian east coast low (ECL) is both a major cause of damaging severe weather and an important contributor to rainfall and dam inflow along the east coast, and is of interest to a wide range of groups including catchment managers and emergency services. For this reason, several studies in recent years have developed and interrogated databases of east coast lows using a variety of automated cyclone detection methods and identification criteria. This paper retunes each method so that all yield a similar event frequency within the ECL region, to enable a detailed intercomparison of the similarities, differences, and relative advantages of each method. All methods are shown to have substantial skill at identifying ECL events leading to major impacts or explosive development, but the choice of method significantly affects both the seasonal and interannual variation of detected ECL numbers. This must be taken into consideration in studies on trends or variability in ECLs, with a subcategorization of ECL events by synoptic situation of key importance.
Orographic precipitation and water vapor fractionation over the southern Andes
Publisher: American Meteorological Society
Date: 02-2007
DOI: 10.1175/JHM555.1
Abstract: The climatological nature of orographic precipitation in the southern Andes between 40° and 48°S is investigated primarily using stable isotope data from streamwater. In addition, four precipitation events are examined using balloon soundings and satellite images. The Moderate Resolution Imaging Spectroradiometer (MODIS) images taken during precipitation events reveal complex patterns of upstream open-cell convection over the ocean, stratus and/or convective clouds over the mountains, and sharp leeside clearing and roll convection over the steppe. Using the water vapor bands on MODIS reveals a sharp drop in column water vapor from about 1.4 to 0.7 cm across the mountain range. Seventy-one water s les from streams across the southern Andes provide deuterium and oxygen-18 isotope data to determine the drying ratio (DR) of airstreams crossing the mountain range and to constrain free parameters in a mathematical model of orographic precipitation. From the strong isotope fractionation associated with orographic precipitation, it is estimated that DR is ∼50%, the highest value yet found for a mountain range. The cloud delay parameters in a high-resolution linear precipitation model were optimized to fit the streamwater isotope data. The model agrees well with the data when the cloud delay time (i.e., elapsed time from condensation to precipitation) is about 1700 s. The tuned model is used to discuss the small-scale spatial pattern of precipitation. The isotope data from streams are also compared with data from sapwater. The good agreement suggests that future isotope mapping could be done using trees.
Influence of antecedent soil moisture conditions on the synoptic meteorology of the Black Saturday bushfire event in southeast Australia
Publisher: Wiley
Date: 12-08-2015
DOI: 10.1002/QJ.2596
Can sub-daily multivariate bias correction of regional climate model boundary conditions improve simulation of the diurnal precipitation cycle?
Publisher: Authorea, Inc.
Date: 08-05-2023
DOI: 10.22541/ESSOAR.168351202.25973894/V1
Abstract: The diurnal cycle is often poorly reproduced in global climate model (GCM) simulations, particularly in terms of rainfall frequency and litude. While improvements in the regional climate model (RCM) with bias-corrected boundaries have been reported in previous studies, they assumed that diurnal patterns are simulated correctly by the GCM, potentially leading to inaccuracies in the maximum rainfall timing and magnitude within the RCM domain. Here we provide the first examination of improvements to the diurnal cycle, within a RCM domain, achieved through the use of sophisticated bias-corrected lateral and lower boundary conditions. Results show that the RCMs with bias-corrected boundaries generally present improvement in capturing both rainfall timing and magnitude, particularly in northern Australia, where a strong diurnal pattern in rainfall is prevalent. We show that correcting systematic sub-daily multivariate bias in RCM boundaries improves the diurnal rainfall cycle, which is particularly important in regions where short-term intense precipitation occurs.
Technical Note: Reducing the spin-up time of integrated surface water–groundwater models
Publisher: Copernicus GmbH
Date: 26-06-2014
DOI: 10.5194/HESSD-11-6969-2014
Abstract: Abstract. One of the main challenges in catchment scale application of coupled/integrated hydrologic models is specifying a catchment's initial conditions in terms of soil moisture and depth to water table (DTWT) distributions. One approach to reduce uncertainty in model initialization is to run the model recursively using a single or multiple years of forcing data until the system equilibrates with respect to state and diagnostic variables. However, such "spin-up" approaches often require many years of simulations, making them computationally intensive. In this study, a new hybrid approach was developed to reduce the computational burden of spin-up time for an integrated groundwater-surface water-land surface model (ParFlow.CLM) by using a combination of ParFlow.CLM simulations and an empirical DTWT function. The methodology is examined in two catchments located in the temperate and semi-arid regions of Denmark and Australia respectively. Our results illustrate that the hybrid approach reduced the spin-up time required by ParFlow.CLM by up to 50%, and we outline a methodology that is applicable to other coupled/integrated modelling frameworks when initialization from equilibrium state is required.
Resolving vorticity-driven lateral fire spread using the WRF-Fire coupled atmosphere–fire numerical model
Publisher: Copernicus GmbH
Date: 05-09-2014
DOI: 10.5194/NHESS-14-2359-2014
Abstract: Abstract. Vorticity-driven lateral fire spread (VLS) is a form of dynamic fire behaviour, during which a wildland fire spreads rapidly across a steep leeward slope in a direction approximately transverse to the background winds. VLS is often accompanied by a downwind extension of the active flaming region and intense pyro-convection. In this study, the WRF-Fire (WRF stands for Weather Research and Forecasting) coupled atmosphere–fire model is used to examine the sensitivity of resolving VLS to both the horizontal and vertical grid spacing, and the fire-to-atmosphere coupling from within the model framework. The atmospheric horizontal and vertical grid spacing are varied between 25 and 90 m, and the fire-to-atmosphere coupling is either enabled or disabled. At high spatial resolutions, the inclusion of fire-to-atmosphere coupling increases the upslope and lateral rate of spread by factors of up to 2.7 and 9.5, respectively. This increase in the upslope and lateral rate of spread diminishes at coarser spatial resolutions, and VLS is not modelled for a horizontal and vertical grid spacing of 90 m. The lateral fire spread is driven by fire whirls formed due to an interaction between the background winds and the vertical circulation generated at the flank of the fire front as part of the pyro-convective updraft. The laterally advancing fire fronts become the dominant contributors to the extreme pyro-convection. The results presented in this study demonstrate that both high spatial resolution and two-way atmosphere–fire coupling are required to model VLS with WRF-Fire.
The Impact of Interacting Climate Modes on East Australian Precipitation Moisture Sources
Publisher: American Meteorological Society
Date: 15-05-2022
Abstract: Modes of climate variability can drive significant changes to regional climate affecting extremes such as droughts, floods, and bushfires. The need to forecast these extremes and expected future increases in their intensity and frequency motivates a need to better understand the physical processes that connect climate modes to regional precipitation. Focusing on east Australia, where precipitation is driven by multiple interacting climate modes, this study provides a new perspective into the links between large-scale modes of climate variability and precipitation. Using a Lagrangian back-trajectory approach, we examine how El Niño–Southern Oscillation (ENSO) modifies the supply of evaporative moisture for precipitation, and how this is modulated by the Indian Ocean dipole (IOD) and southern annular mode (SAM). We demonstrate that La Niña modifies large-scale moisture transport together with local thermodynamic changes to facilitate local precipitation generation, whereas below-average precipitation during El Niño stems predominantly from increased regional subsidence. These dynamic–thermodynamic processes were often more pronounced during co-occurring La Niña/negative IOD and El Niño ositive IOD periods. As the SAM is less strongly correlated with ENSO, the impact of co-occurring ENSO and SAM largely depended on the state of ENSO. La Niña–related processes were exacerbated when combined with +SAM and d ened when combined with −SAM, and vice versa during El Niño. This new perspective on how interacting climate modes physically influence regional precipitation can help elucidate how model biases affect the simulation of Australian climate, facilitating model improvement and understanding of regional impacts from long-term changes in these modes. How climate modes modulate the oceanic and terrestrial sources of moisture for rainfall in east Australia is investigated. East Australia is wetter during La Niña because more moisture is transported into the region and is more easily turned into rainfall when it arrives, whereas drier conditions during El Niño are because local conditions inhibit the conversion of moisture into rainfall. Distant atmospheric changes over the Indian and Southern Oceans can intensify these changes. Our results can be used to better understand and predict the regional impact of long-term changes in these modes of climate variability, which are potentially altered under climate change.
Investigating the mechanisms of diurnal rainfall variability using a regional climate model
Publisher: American Meteorological Society
Date: 24-04-2012
DOI: 10.1175/JCLI-D-11-00616.1
Abstract: This study investigates the ability of a regional climate model (RCM) to simulate the diurnal cycle of precipitation over southeast Australia, to provide a basis for understanding the mechanisms that drive diurnal variability. When compared with 195 observation gauges, the RCM tends to simulate too many occurrences and too little intensity for precipitation events at the 3-hourly time scale. However, the overall precipitation amounts are well simulated and the diurnal variability in occurrences and intensities are generally well reproduced, particularly in spring and summer. In terms of precipitation amounts, the RCM overestimated the diurnal cycle during the warmer months but was reasonably accurate during winter. The timing of the maxima and minima was found to match the observed timings well. The spatial pattern of diurnal variability in the Weather Research and Forecasting model outputs was remarkably similar to the observed record, capturing many features of regional variability. The RCM diurnal cycle was dominated by the convective (subgrid scale) precipitation. In the RCM the diurnal cycle of convective precipitation over land corresponds well to atmospheric instability and thermally triggered convection over large areas, and also to the large-scale moisture convergence at 700 hPa along the east coast, with the strongest diurnal cycles present where these three mechanisms are in phase.
Strong Intensification of Hourly Rainfall Extremes by Urbanization
Publisher: American Geophysical Union (AGU)
Date: 21-07-2020
DOI: 10.1029/2020GL088758
Abstract: Although observations and modeling studies show that heavy rainfall is increasing in many regions, how changes will manifest themselves on sub‐daily timescales remains highly uncertain. Here, for the first time, we combine observational analysis and high‐resolution modeling results to examine changes to extreme rainfall intensities in urbanized Kuala Lumpur, Malaysia. We find that hourly intensities of extreme rainfall have increased by ~35% over the last three decades, nearly 3 times more than in surrounding rural areas, with daily intensities showing much weaker increases. Our modeling results confirm that the urban heat island effect creates a more unstable atmosphere, increased vertical uplift and moisture convergence. This, combined with weak surface winds in the Tropics, causes intensification of rainfall extremes over the city, with reduced rainfall in the surrounding region.
Correcting lateral boundary biases in regional climate modelling: the effect of the relaxation zone
Publisher: Springer Science and Business Media LLC
Date: 08-2020
Brominated indoles from a marine mollusc inhibit inflammation in a murine model of acute lung injury
Publisher: Public Library of Science (PLoS)
Date: 26-10-2017
Derived Optimal Linear Combination Evapotranspiration (DOLCE): a global gridded synthesis ET estimate
Publisher: Copernicus GmbH
Date: 21-02-2018
DOI: 10.5194/HESS-22-1317-2018
Abstract: Abstract. Accurate global gridded estimates of evapotranspiration (ET) are key to understanding water and energy budgets, in addition to being required for model evaluation. Several gridded ET products have already been developed which differ in their data requirements, the approaches used to derive them and their estimates, yet it is not clear which provides the most reliable estimates. This paper presents a new global ET dataset and associated uncertainty with monthly temporal resolution for 2000–2009. Six existing gridded ET products are combined using a weighting approach trained by observational datasets from 159 FLUXNET sites. The weighting method is based on a technique that provides an analytically optimal linear combination of ET products compared to site data and accounts for both the performance differences and error covariance between the participating ET products. We examine the performance of the weighting approach in several in-s le and out-of-s le tests that confirm that point-based estimates of flux towers provide information on the grid scale of these products. We also provide evidence that the weighted product performs better than its six constituent ET product members in four common metrics. Uncertainty in the ET estimate is derived by rescaling the spread of participating ET products so that their spread reflects the ability of the weighted mean estimate to match flux tower data. While issues in observational data and any common biases in participating ET datasets are limitations to the success of this approach, future datasets can easily be incorporated and enhance the derived product.
Modelling the dynamic behaviour of junction fires with a coupled atmosphere–fire model
Publisher: CSIRO Publishing
Date: 2017
DOI: 10.1071/WF16079
Abstract: Dynamic fire behaviour involves rapid changes in fire behaviour without significant changes in ambient conditions, and can compromise firefighter and community safety. Dynamic fire behaviour cannot be captured using spatial implementations of empirical fire-spread models predicated on the assumption of an equilibrium, or quasi-steady, rate of spread. In this study, a coupled atmosphere–fire model is used to model the dynamic propagation of junction fires, i.e. when two firelines merge at an oblique angle. This involves very rapid initial rates of spread, even with no ambient wind. The simulations are in good qualitative agreement with a previous experimental study, and indicate that pyro-convective interaction between the fire and the atmosphere is the key mechanism driving the dynamic fire propagation. An examination of the vertical vorticity in the simulations, and its relationship to the fireline geometry, gives insight into this mechanism. Junction fires have been modelled previously using curvature-dependent rates of spread. In this study, however, although fireline geometry clearly influences rate of spread, no relationship is found between local fireline curvature and the simulated instantaneous local rate of spread. It is possible that such a relationship may be found at larger scales.
Evaluating the effect of climate change on areal reduction factors using regional climate model projections
Publisher: Elsevier BV
Date: 09-2015
Regional climate model projections of the South Pacific Convergence Zone
Publisher: Springer Science and Business Media LLC
Date: 17-10-2015
Hypomethylation of the IL17RC Promoter in Peripheral Blood Leukocytes Is Not A Hallmark of Age-Related Macular Degeneration
Publisher: Elsevier BV
Date: 12-2013
Projected change in characteristics of near surface temperature inversions for southeast Australia
Publisher: Springer Science and Business Media LLC
Date: 08-05-2019
Evaluating regional climate models for simulating sub-daily rainfall extremes
Publisher: Springer Science and Business Media LLC
Date: 28-11-2015
The Variable Region of Pneumococcal Pathogenicity Island 1 Is Responsible for Unusually High Virulence of a Serotype 1 Isolate
Publisher: American Society for Microbiology
Date: 03-2016
DOI: 10.1128/IAI.01454-15
Abstract: Streptococcus pneumoniae is the leading infectious cause of death in children in the world. However, the mechanisms that drive the progression from asymptomatic colonization to disease are poorly understood. Two virulence-associated genomic accessory regions (ARs) were deleted in a highly virulent serotype 1 clinical isolate (strain 4496) and examined for their contribution to pathogenesis. Deletion of a prophage encoding a platelet-binding protein (PblB) resulted in reduced adherence, biofilm formation, reduced initial infection within the lungs, and a reduction in the number of circulating platelets in infected mice. However, the region's overall contribution to the survival of mice was not significant. In contrast, deletion of the variable region of pneumococcal pathogenicity island 1 (vPPI1) was also responsible for a reduction in adherence and biofilm formation but also reduced survival and invasion of the pleural cavity, blood, and lungs. While the 4496ΔPPI1 strain induced higher expression of the genes encoding interleukin-10 (IL-10) and CD11b in the lungs of challenged mice than the wild-type strain, very few other genes exhibited altered expression. Moreover, while the level of IL-10 protein was increased in the lungs of 4496ΔPPI1 mutant-infected mice compared to strain 4496-infected mice, the levels of gamma interferon (IFN-γ), CXCL10, CCL2, and CCL4 were not different in the two groups. However, the 4496ΔPPI1 mutant was found to be more susceptible than the wild type to phagocytic killing by a macrophage-like cell line. Therefore, our data suggest that vPPI1 may be a major contributing factor to the heightened virulence of certain serotype 1 strains, possibly by influencing resistance to phagocytic killing.
The resilience of Australian wind energy to climate change
Publisher: IOP Publishing
Date: 02-2018
Realised added value in dynamical downscaling of Australian climate change
Publisher: Springer Science and Business Media LLC
Date: 27-04-2020
Effect of model resolution on a regional climate model simulation over southeast Australia
Publisher: Inter-Research Science Center
Date: 26-03-2013
DOI: 10.3354/CR01151
Linear Optimal Runoff Aggregate (LORA): A global gridded synthesis runoff product
Publisher: Copernicus GmbH
Date: 07-08-2018
Abstract: Abstract. No synthesized global gridded runoff product, derived from multiple sources, is available despite such a product being useful to meet the needs of many global water initiatives. We apply an optimal weighting approach to merge runoff estimates from hydrological models constrained with observational streamflow records. The weighting method is based on the ability of the models to match observed streamflow data while accounting for error covariance between the participating products. To address the lack of observed streamflow for many regions, a dissimilarity method was applied to transfer the weights of the participating products to the ungauged basins from the closest gauged basins using dissimilarity between basins in physiographic and climatic characteristics as a proxy for distance. We perform out-of-s le tests to examine the success of the dissimilarity approach and we confirm that the weighted product performs better than its 11 constituents products in a range of metrics. Our resulting synthesized global gridded runoff product is available at monthly time scales, and includes time variant uncertainty, for the period 1980–2012 on a 0.5° grid. The synthesized global gridded runoff product broadly agrees with published runoff estimates at many river basins, and represents well the seasonal runoff cycle for most of the globe. The new product, called Linear Optimal Runoff Aggregate (LORA), is a valuable synthesis of existing runoff products and will be freely available for download on geonetwork.nci.org.au/.
Evaluating a regional climate model's ability to simulate the climate of the South-east coast of Australia
Publisher: IOP Publishing
Date: 08-2010
Implementation of a soil albedo scheme in the CABLEv1.4b land surface model and evaluation against MODIS estimates over Australia
Publisher: Copernicus GmbH
Date: 23-09-2014
Abstract: Abstract. Land surface albedo, the fraction of incoming solar radiation reflected by the land surface, is a key component of the Earth system. This study evaluates snow-free surface albedo simulations by the Community Atmosphere Biosphere Land Exchange (CABLEv1.4b) model with the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Satellite Pour L'Observation de la Terre (SPOT) albedo. We compare results from offline simulations over the Australian continent. The control simulation has prescribed background snow-free and vegetation-free soil albedo derived from MODIS whilst the experiments use a simple parameterisation based on soil moisture and colour, originally from the Biosphere Atmosphere Transfer Scheme (BATS), and adopted in the Common Land Model (CLM). The control simulation, with prescribed soil albedo, shows that CABLE simulates overall albedo over Australia reasonably well, with differences compared to MODIS and SPOT albedos within ±0.1. Application of the original BATS scheme, which uses an eight-class soil classification, resulted in large differences of up to −0.25 for the near-infrared (NIR) albedo over large parts of the desert regions of central Australia. The use of a recalibrated 20-class soil colour classification from the CLM, which includes a higher range for saturated and VIS (visible) and NIR soil albedos, reduced the underestimation of the NIR albedo. However, this soil colour mapping is tuned to CLM soil moisture, a quantity which is not necessarily transferrable between land surface models. We therefore recalibrated the soil color map using CABLE's climatological soil moisture, which further reduced the underestimation of the NIR albedo to within ±0.15 over most of the continent as compared to MODIS and SPOT albedos. Small areas of larger differences of up to −0.25 remained within the central arid parts of the continent during summer however, the spatial extent of these large differences is substantially reduced as compared to the simulation using the default eight-class uncalibrated soil colour map. It is now possible to use CABLE coupled to atmospheric models to investigate soil-moisture–albedo feedbacks, an important enhancement of the model.
Linear Optimal Runoff Aggregate (LORA): a global gridded synthesis runoff product
Publisher: Copernicus GmbH
Date: 13-02-2019
Abstract: Abstract. No synthesized global gridded runoff product, derived from multiple sources, is available, despite such a product being useful for meeting the needs of many global water initiatives. We apply an optimal weighting approach to merge runoff estimates from hydrological models constrained with observational streamflow records. The weighting method is based on the ability of the models to match observed streamflow data while accounting for error covariance between the participating products. To address the lack of observed streamflow for many regions, a dissimilarity method was applied to transfer the weights of the participating products to the ungauged basins from the closest gauged basins using dissimilarity between basins in physiographic and climatic characteristics as a proxy for distance. We perform out-of-s le tests to examine the success of the dissimilarity approach, and we confirm that the weighted product performs better than its 11 constituent products in a range of metrics. Our resulting synthesized global gridded runoff product is available at monthly timescales, and includes time-variant uncertainty, for the period 1980–2012 on a 0.5∘ grid. The synthesized global gridded runoff product broadly agrees with published runoff estimates at many river basins, and represents the seasonal runoff cycle for most of the globe well. The new product, called Linear Optimal Runoff Aggregate (LORA), is a valuable synthesis of existing runoff products and will be freely available for download on geonetwork.nci.org.au/geonetwork/srv/eng/catalog.search#/metadata/f9617_9854_8096_5291 (last access: 31 January 2019).
Future changes to the intensity and frequency of short-duration extreme rainfall
Publisher: American Geophysical Union (AGU)
Date: 27-08-2014
DOI: 10.1002/2014RG000464
A novel method to test non-exclusive hypotheses applied to Arctic ice projections from dependent models
Publisher: Springer Science and Business Media LLC
Date: 09-07-2019
DOI: 10.1038/S41467-019-10561-X
Abstract: A major conundrum in climate science is how to account for dependence between climate models. This complicates interpretation of probabilistic projections derived from such models. Here we show that this problem can be addressed using a novel method to test multiple non-exclusive hypotheses, and to make predictions under such hypotheses. We apply the method to probabilistically estimate the level of global warming needed for a September ice-free Arctic, using an ensemble of historical and representative concentration pathway 8.5 emissions scenario climate model runs. We show that not accounting for model dependence can lead to biased projections. Incorporating more constraints on models may minimize the impact of neglecting model non-exclusivity. Most likely, September Arctic sea ice will effectively disappear at between approximately 2 and 2.5 K of global warming. Yet, limiting the warming to 1.5 K under the Paris agreement may not be sufficient to prevent the ice-free Arctic.
The effect of bias correction and climate model resolution on wheat simulations forced with a regional climate model ensemble
Publisher: Wiley
Date: 04-02-2016
DOI: 10.1002/JOC.4653
A Bayesian posterior predictive framework for weighting ensemble regional climate models
Publisher: Copernicus GmbH
Date: 04-01-2017
DOI: 10.5194/GMD-2016-291
Abstract: Abstract. We present a novel Bayesian statistical approach to computing model weights in climate change We present a novel Bayesian statistical approach to computing model weights in climate change projection ensembles. The weight of each climate model is obtained by weighting the current day observed data under the posterior distribution admitted under competing climate models. We use a linear model to describe the model output and observations. The approach accounts for uncertainty in model bias, trend and internal variability, as well as including error in the observations used. Our framework is general, requires very little problem specific input, and works well with default priors. We carry out cross-validation checks that confirm that the method produces the correct coverage.
Exploring the future change space for fire weather in southeast Australia
Publisher: Springer Science and Business Media LLC
Date: 15-05-2019
Rapid Warming in the Australian Alps from Observation and NARCliM Simulations
Publisher: MDPI AG
Date: 14-10-2022
Abstract: The Australian Alps are the highest mountain range in Australia, which are important for bio ersity, energy generation and winter tourism. Significant increases in temperature in the past decades has had a huge impact on bio ersity and ecosystem in this region. In this study, observed temperature is used to assess how temperature changed over the Australian Alps and surrounding areas. We also use outputs from two generations of NARCliM (NSW and Australian Regional Climate Modelling) to investigate spatial and temporal variation of future changes in temperature and its extremes. The results show temperature increases faster for the Australian Alps than the surrounding areas, with clear spatial and temporal variation. The changes in temperature and its extremes are found to be strongly correlated with changes in albedo, which suggests faster warming in cool season might be dominated by decrease in albedo resulting from future changes in natural snowfall and snowpack. The warming induced reduction in future snow cover in the Australian Alps will have a significant impact on this region.
Resolution Sensitivity of Cyclone Climatology over Eastern Australia Using Six Reanalysis Products
Publisher: American Meteorological Society
Date: 15-01-2015
DOI: 10.1175/JCLI-D-14-00645.1
Abstract: The climate of the eastern seaboard of Australia is strongly influenced by the passage of low pressure systems over the adjacent Tasman Sea due to their associated precipitation and their potential to develop into extreme weather events. The aim of this study is to quantify differences in the climatology of east coast lows derived from the use of six global reanalyses. The methodology is explicitly designed to identify differences between reanalyses arising from differences in their horizontal resolution and their structure (type of forecast model, assimilation scheme, and the kind and number of observations assimilated). As a basis for comparison, reanalysis climatologies are compared with an observation-based climatology. Results show that reanalyses, specially high-resolution products, lead to very similar climatologies of the frequency, intensity, duration, and size of east coast lows when using spatially smoothed (about 300-km horizontal grid meshes) mean sea level pressure fields as input data. Moreover, at these coarse horizontal scales, monthly, interannual, and spatial variabilities appear to be very similar across the various reanalyses with a generally stronger agreement between winter events compared with summer ones. Results also show that, when looking at cyclones using reanalysis data at their native resolution (approaching 50-km grid spacing for the most recent products), uncertainties related to the frequency, intensity, and size of lows are very large and it is not clear which reanalysis, if any, gives a better description of cyclones. Further work is needed in order to evaluate the usefulness of the finescale information in modern reanalyses and to better understand the sources of their differences.
Global warming impact on the dominant precipitation processes in the Middle East
Publisher: Springer Science and Business Media LLC
Date: 19-05-2010
Supplementary material to A systematic review of climate change science relevant to Australian design flood estimation
Publisher: Copernicus GmbH
Date: 10-10-2023
Resolving the influence of local flows on urban heat amplification during heatwaves
Publisher: IOP Publishing
Date: 06-2021
Abstract: Heatwaves have implications for human health and ecosystem function. Over cities, the impacts of a heatwave event may be compounded by urban heat, where temperatures over the urban area are higher than their rural surroundings. Coastal cities often rely upon sea breezes to provide temporary relief. However, topographic features contributing to the development of Foehn-like conditions can offset the cooling influence of sea breezes. Using convection-permitting simulations (⩽4 km) we examine the potential for both mechanisms to influence heatwave conditions over the large coastal city of Sydney, Australia that is bordered by mountains. Heatwave onset in the hot period of January–February 2017 often coincides with a hot continental flow over the mountains into the city. The temperature difference between the coast and the urban–rural interface can reach 15.79 °C. Further, the urban heat island contributes on average an additional 1 °C in the lowest 1 km of the atmosphere and this often extends beyond the city limits. The cumulative heat induced by the urban environment reaches 10 °C over the city and 3 °C over adjacent inland areas. Strong sea breezes are important for heat dispersion with city temperature gradients reducing to within 1 °C. The resolution permits a comparison between urban types and reveals that the diurnal cycle of temperature, moisture content and wind are sensitive to the urban type. Here we show that convection permitting simulations can resolve the interaction between local breezes and the urban environment that are not currently resolved in coarser resolution models.
Development of a simple, catchment-scale, rainfall-evapotranspiration-runoff model
Publisher: Elsevier BV
Date: 10-1998
Identification of Genes That Contribute to the Pathogenesis of Invasive Pneumococcal Disease by In Vivo Transcriptomic Analysis
Publisher: American Society for Microbiology
Date: 09-2012
DOI: 10.1128/IAI.00295-12
Abstract: Streptococcus pneumoniae (the pneumococcus) continues to be responsible for a high level of global morbidity and mortality resulting from pneumonia, bacteremia, meningitis, and otitis media. Here we have used a novel technique involving niche-specific, genome-wide in vivo transcriptomic analyses to identify genes upregulated in distinct niches during pathogenesis after intranasal infection of mice with serotype 4 or 6A pneumococci. The analyses yielded 28 common, significantly upregulated genes in the lungs relative to those in the nasopharynx and 25 significantly upregulated genes in the blood relative to those in the lungs in both strains, some of which were previously unrecognized. The role of five upregulated genes from either the lungs or the blood in pneumococcal pathogenesis and virulence was then evaluated by targeted mutagenesis. One of the mutants (Δ malX ) was significantly attenuated for virulence in the lungs, two (Δ aliA and Δ ilvH ) were significantly attenuated for virulence in the blood relative to the wild type, and two others (Δ cbiO and Δ piuA ) were completely avirulent in a mouse intranasal challenge model. We also show that the products of aliA , malX , and piuA are promising candidates for incorporation into multicomponent protein-based pneumococcal vaccines currently under development. Importantly, we suggest that this new approach is a viable complement to existing strategies for the discovery of genes critical to the distinct stages of invasive pneumococcal disease and potentially has broad application for novel protein antigen discovery in other pathogens such as S. pyogenes , Haemophilus influenzae type b, and Neisseria meningitidis .
Australian Precipitation Recycling and Evaporative Source Regions
Publisher: American Meteorological Society
Date: 15-10-2020
Abstract: The relative importance of atmospheric advection and local land–atmosphere coupling to Australian precipitation is uncertain. Identifying the evaporative source regions and level of precipitation recycling can help quantify the importance of local and remote marine and terrestrial moisture to precipitation within the different hydroclimates across Australia. Using a three-dimensional Lagrangian back-trajectory approach, moisture from precipitation events across Australia during 1979–2013 was tracked to determine the source of moisture (the evaporative origin) and level of precipitation recycling. We show that source regions vary markedly for precipitation falling in different regions. Advected marine moisture was relatively more important than terrestrial contributions for precipitation in all regions and seasons. For Australia as a whole, contributions from precipitation recycling varied from ~11% in winter up to ~21% in summer. The strongest land–atmosphere coupling was in the northwest and southeast where recycled local land evapotranspiration accounted for an average of 9% of warm-season precipitation. Marine contributions to precipitation in the northwest of Australia increased in spring and, coupled with positive evaporation trends in the key source regions, suggest that the observed precipitation increase is the result of intensified evaporation in the Maritime Continent and Indian and Pacific Oceans. Less clear were the processes behind an observed shift in moisture contribution from winter to summer in southeastern Australia. Establishing the climatological source regions and the magnitude of moisture recycling enables future investigation of anomalous precipitation during extreme periods and provides further insight into the processes driving Australia’s variable precipitation.
A conditional disaggregation algorithm for generating fine time-scale rainfall data in a warmer climate
Publisher: Elsevier BV
Date: 02-2013
Reconciling historical changes in the hydrological cycle over land
Publisher: Springer Science and Business Media LLC
Date: 14-03-2022
DOI: 10.1038/S41612-022-00240-Y
Abstract: The sixth Intergovernmental Panel on Climate Change (IPCC) assessment report confirms that global warming drives widespread changes in the global terrestrial hydrological cycle, and that changes are regionally erse. However, reported trends and changes in the hydrological cycle suffer from significant inconsistencies. This is associated with the lack of a rigorous observationally-based assessment of simultaneous trends in the different components of the hydrological cycle. Here, we reconcile these different estimates of historical changes by simultaneously analysing trends in all the major components of the hydrological cycle, coupled with vegetation greenness for the period 1980–2012. We use observationally constrained, conserving estimates of the closure of the hydrological cycle, combined with a data assimilation approach and observationally-driven uncertainty estimates. We find robust changes in the hydrological cycle across more than 50% of the land area, with evapotranspiration (ET) changing the most and precipitation ( P ) the least. We find many instances of unambiguous trends in ET and runoff ( Q ) without robust trends in P , a result broadly consistent with a “wet gets wetter, but dry does not get drier”. These findings provide important opportunities for water resources management and climate risk assessment over a significant fraction of the land surface where hydrological trends have previously been uncertain.
The use of uncorrected regional climate model output to force impact models: a case study for wheat simulations
Publisher: Inter-Research Science Center
Date: 20-10-2014
DOI: 10.3354/CR01258
Land surface albedo and vegetation feedbacks enhanced the Millennium drought in south-east Australia
Publisher: Copernicus GmbH
Date: 29-08-2016
Abstract: Abstract. In this study we have examined the ability of a regional climate model (RCM) to simulate the extended drought that occurred throughout the period 2002 through 2007 in southeast Australia. In particular, the ability to reproduce the two drought peaks in 2002 and 2006 was investigated. Overall the RCM was found to reproduce both the temporal and the spatial structure of the drought related precipitation anomalies quite well, despite using climatological seasonal surface characteristics such as vegetation fraction and albedo. This result concurs with previous studies that found that about two thirds of the precipitation decline can be attributed to ENSO. Simulation experiments that allowed the vegetation fraction and albedo to vary as observed illustrated that the intensity of the drought was underestimated by about 10% when using climatological surface characteristics. These results suggest that in terms of drought development, capturing the feedbacks related to vegetation and albedo changes may be as important as capturing the soil moisture-precipitation feedback. In order to improve our modelling of multi-year droughts the challenge is to capture all these related surface changes simultaneously, and provide a comprehensive description of land surface-precipitation feedback during the droughts development.
Estimating grassland curing with remotely sensed data
Publisher: Copernicus GmbH
Date: 04-06-2018
DOI: 10.5194/NHESS-18-1535-2018
Abstract: Abstract. Wildfire can become a catastrophic natural hazard, especially during dry summer seasons in Australia. Severity is influenced by various meteorological, geographical, and fuel characteristics. Modified Mark 4 McArthur's Grassland Fire Danger Index (GFDI) is a commonly used approach to determine the fire danger level in grassland ecosystems. The degree of curing (DOC, i.e. proportion of dead material) of the grass is one key ingredient in determining the fire danger. It is difficult to collect accurate DOC information in the field, and therefore ground-observed measurements are rather limited. In this study, we explore the possibility of whether adding satellite-observed data responding to vegetation water content (vegetation optical depth, VOD) will improve DOC prediction when compared with the existing satellite-observed data responding to DOC prediction models based on vegetation greenness (normalised difference vegetation index, NDVI). First, statistically significant relationships are established between selected ground-observed DOC and satellite-observed vegetation datasets (NDVI and VOD) with an r2 up to 0.67. DOC levels estimated using satellite observations were then evaluated using field measurements with an r2 of 0.44 to 0.55. Results suggest that VOD-based DOC estimation can reasonably reproduce ground-based observations in space and time and is comparable to the existing NDVI-based DOC estimation models.
The importance of the Zagros mountains barrier jet to future precipitation in the fertile crescent
Publisher: Bentham Science Publishers Ltd.
Date: 27-08-2011
DOI: 10.2174/1874282301105010087
Abstract: This study quantifies the significance of southerly water vapour fluxes, associated with the Zagros Mountains barrier jet, on precipitation occurring in the Eastern Fertile Crescent region and its change due to global warming. Precipitation events are simulated using a Regional Climate Model (MM5-Noah) driven by boundary conditions from a CCSM global climate model simulation with the SRES A2 emission scenario. The precipitation events were grouped into classes based on the similarity of their water vapour fluxes. Results show a massive increase in the southerly dominated classes which are associated with the formation of a barrier jet on the western slopes of the Zagros Mountains. This increase was related to an increase in atmospheric water vapour in the southern portion of the domain rather than to an increase in the frequency of formation or wind speed of the barrier jet itself. The presence of this barrier jet becomes increasingly important to precipitation in the Eastern Fertile Crescent region as global warming progresses. Thus, low resolution models that are unable to capture this phenomena will produce questionable future projections for this region.
Supplementary material to "Derived Optimal Linear Combination Evapotranspiration (DOLCE): a global gridded synthesis ET estimate"
Publisher: Copernicus GmbH
Date: 03-04-2017
Assessing atmospheric bias correction for dynamical consistency using potential vorticity
Publisher: IOP Publishing
Date: 12-2014
Correction: Alhamami et al. First Emergence of Resistance to Macrolides and Tetracycline Identified in Mannheimia haemolytica and Pasteurella multocida Isolates from Beef Feedlots in Australia. Microorganisms 2021, 9, 1322
Publisher: MDPI AG
Date: 15-04-2022
DOI: 10.3390/MICROORGANISMS10040825
Abstract: The authors wish to make the following corrections to this paper [...]
Characterization of Pneumococcal Genes Involved in Bloodstream Invasion in a Mouse Model
Publisher: Public Library of Science (PLoS)
Date: 05-11-2015
Comparative Proteomics of Marinobacter sp. TT1 Reveals Corexit Impacts on Hydrocarbon Metabolism, Chemotactic Motility, and Biofilm Formation
Publisher: MDPI AG
Date: 22-12-2020
DOI: 10.3390/MICROORGANISMS9010003
Abstract: The application of chemical dispersants during marine oil spills can affect the community composition and activity of marine microorganisms. Several studies have indicated that certain marine hydrocarbon-degrading bacteria, such as Marinobacter spp., can be inhibited by chemical dispersants, resulting in lower abundances and/or reduced biodegradation rates. However, a major knowledge gap exists regarding the mechanisms underlying these physiological effects. Here, we performed comparative proteomics of the Deepwater Horizon isolate Marinobacter sp. TT1 grown under different conditions. Strain TT1 received different carbon sources (pyruvate vs. n-hexadecane) with and without added dispersant (Corexit EC9500A). Additional treatments contained crude oil in the form of a water-accommodated fraction (WAF) or chemically-enhanced WAF (CEWAF with Corexit). For the first time, we identified the proteins associated with alkane metabolism and alginate biosynthesis in strain TT1, report on its potential for aromatic hydrocarbon biodegradation and present a protein-based proposed metabolism of Corexit components as carbon substrates. Our findings revealed that Corexit exposure affects hydrocarbon metabolism, chemotactic motility, biofilm formation, and induces solvent tolerance mechanisms, like efflux pumps, in strain TT1. This study provides novel insights into dispersant impacts on microbial hydrocarbon degraders that should be taken into consideration for future oil spill response actions.
Natural hazards in Australia: floods
Publisher: Springer Science and Business Media LLC
Date: 11-05-2016
Robust historical evapotranspiration trends across climate regimes
Publisher: Copernicus GmbH
Date: 06-07-2021
DOI: 10.5194/HESS-25-3855-2021
Abstract: Abstract. Evapotranspiration (ET) links the hydrological, energy and carbon cycles on the land surface. Quantifying ET and its spatio-temporal changes is also key to understanding climate extremes such as droughts, heatwaves and flooding. Regional ET estimates require reliable observation-based gridded ET datasets, and while many have been developed using physically based, empirically based and hybrid techniques, their efficacy, and particularly the efficacy of their uncertainty estimates, is difficult to verify. In this work, we extend the methodology used in Hobeichi et al. (2018) to derive two new versions of the Derived Optimal Linear Combination Evapotranspiration (DOLCE) product, with observationally constrained spatio-temporally varying uncertainty estimates, higher spatial resolution, more constituent products and extended temporal coverage (1980–2018). After demonstrating the efficacy of these uncertainty estimates with out-of-s le testing, we derive novel ET climatology clusters for the land surface, based on the magnitude and variability of ET at each location on land. The new clusters include three wet and three dry regimes and provide an approximation of Köppen–Geiger climate classes. The verified uncertainty estimates and extended time period then allow us to examine the robustness of historical trends spatially and in each of these six ET climatology clusters. We find that despite robust decreasing ET trends in some regions these do not correlate with behavioural ET clusters. Each cluster, and the majority of the Earth's surface, shows clear robust increases in ET over the recent historical period. The new datasets DOLCE V2.1 and DOLCE V3 can be used for benchmarking global ET estimates and for examining ET trends respectively.
Future Changes in the Occurrence of Hybrid Cyclones: The Added Value of Cyclone Classification for the East Australian Low-Pressure Systems
Publisher: American Geophysical Union (AGU)
Date: 20-03-2020
DOI: 10.1029/2019GL085751
Global hotspots for the occurrence of compound events
Publisher: Springer Science and Business Media LLC
Date: 24-11-2020
DOI: 10.1038/S41467-020-19639-3
Abstract: Compound events (CEs) are weather and climate events that result from multiple hazards or drivers with the potential to cause severe socio-economic impacts. Compared with isolated hazards, the multiple hazards/drivers associated with CEs can lead to higher economic losses and death tolls. Here, we provide the first analysis of multiple multivariate CEs potentially causing high-impact floods, droughts, and fires. Using observations and reanalysis data during 1980–2014, we analyse 27 hazard pairs and provide the first spatial estimates of their occurrences on the global scale. We identify hotspots of multivariate CEs including many socio-economically important regions such as North America, Russia and western Europe. We analyse the relative importance of different multivariate CEs in six continental regions to highlight CEs posing the highest risk. Our results provide initial guidance to assess the regional risk of CE events and an observationally-based dataset to aid evaluation of climate models for simulating multivariate CEs.
Climate and vegetation in the Middle East: Interannual variability and drought feedbacks
Publisher: American Meteorological Society
Date: 08-2007
DOI: 10.1175/JCLI4223.1
Abstract: The Euphrates Plain (EP) experiences large interannual variability in vegetation cover, especially in areas of marginal rain-fed agriculture. Vegetation in this region is primarily limited by available soil moisture, as determined by winter precipitation, spring precipitation, and air temperature. Satellite analyses indicate that the springtime normalized difference vegetation index (NDVI) is negatively correlated with surface albedo, and that interannual variability in albedo in the EP produces an estimated forcing on the radiation balance that peaks at 16.0 W m−2 in May. Simulations with a regional climate model indicate that surface energy fluxes during a drought year (1999) differed substantially from those during a year with normal precipitation (2003). These differences were geographically specific, with the EP exhibiting increased albedo and decreased sensible heat flux while the neighboring Zagros Plateau region showed no albedo effect, a large increase in sensible heat flux, and an offsetting reduction in latent heat flux. In both the EP and the Zagros there was a potential for positive feedbacks on temperature and drought in late spring, though the most likely feedback mechanisms differed between the two regions: in the EP surface brightening leads to cooling and reduced turbulent heat flux, while in the Zagros region reduced latent heat flux leads to warming and a deepening of the planetary boundary layer.
Future increases in extreme precipitation exceed observed scaling rates
Publisher: Springer Science and Business Media LLC
Date: 09-01-2017
DOI: 10.1038/NCLIMATE3201
A review of drought in the Middle East and southwest Asia
Publisher: American Meteorological Society
Date: 15-11-2016
DOI: 10.1175/JCLI-D-13-00692.1
Abstract: The Middle East and southwest Asia are a region that is water stressed, societally vulnerable, and prone to severe droughts. Large-scale climate variability, particularly La Niña, appears to play an important role in regionwide droughts, including the two most severe of the last 50 years—1999–2001 and 2007/08—with implications for drought forecasting. Important dynamical factors include orography, thermodynamic influence on vertical motion, storm-track changes, and moisture transport. Vegetation in the region is strongly impacted by drought and may provide an important feedback mechanism. In future projections, drying of the eastern Mediterranean region is a robust feature, as are temperature increases throughout the region, which will affect evaporation and the timing and intensity of snowmelt. Vegetation feedbacks may become more important in a warming climate. There are a wide range of outstanding issues for understanding, monitoring, and predicting drought in the region, including dynamics of the regional storm track, the relative importance of the range of dynamical mechanisms related to drought, the regional coherence of drought, the relationship between synoptic-scale mechanisms and drought, the predictability of vegetation and crop yields, the stability of remote influences, data uncertainty, and the role of temperature. Development of a regional framework for cooperative work and dissemination of information and existing forecasts would speed understanding and make better use of available information.
The NARCliM project: Model agreement and significance of climate projections
Publisher: Inter-Research Science Center
Date: 17-08-2016
DOI: 10.3354/CR01403
Spotty Liver Disease: A review of an ongoing challenge in commercial free-range egg production
Publisher: Elsevier BV
Date: 12-2018
DOI: 10.1016/J.VETMIC.2018.08.004
Abstract: Spotty Liver Disease is an acute infectious disease of layer chickens that was likely first described in the USA and Canada in the 1950s and 1960's. The disease occurs almost exclusively in barn and free-range production systems. Outbreaks usually, but not exclusively occur in young layers (≅25 weeks) at peak of lay. Indicators of SLD include an acute drop in egg production of up to 35%, together with increased mortality of up to 15%. A presumptive diagnosis at post mortem is made with the detection of characteristic small yellow-white necrotic hepatic lesions, together with a fibrinous peri-hepatitis, excess pericardial and peritoneal fluid, and usually enteritis with diarrhoea. Histopathology reveals a multifocal acute hepatocellular necrosis with fibrin and occasional haemorrhage. Control measures trialled include use of antibiotics, improved biosecurity and hygiene, as well as management practices directed at reducing stress in flocks. However, none other than treatment with antibiotics has been consistently effective which suggested a bacterial aetiology. In 2015, a novel fastidious thermophilic, microaerobic c ylobacter was isolated from symptomatic SLD flocks in the UK. Subsequently, an Australian group isolated and further characterised a genetically similar bacterium and named it C ylobacter hepaticus. The bacterium can be cultured from the liver and bile of infected birds, although recovery from non-sterile organs such as the caecum and duodenum remains elusive. Consequently, the route of transmission remains unconfirmed, although molecular detection by PCR of C. hepaticus DNA in the gastrointestinal tract and faeces of SLD infected birds is highly suggestive of a faecal-oral route.
Climate Change Increases the Potential for Extreme Wildfires
Publisher: American Geophysical Union (AGU)
Date: 28-07-2019
DOI: 10.1029/2019GL083699
Abstract: Pyrocumulonimbus (pyroCb) wildfires cause devastation in many regions globally. Given that fire‐atmosphere coupling is associated with pyroCbs, future changes in coincident high index values of atmospheric instability and dryness (C‐Haines) and near‐surface fire weather are assessed for southeastern Australia using a regional climate projection ensemble. We show that observed pyroCb events occur predominantly on forested, rugged landscapes during extreme C‐Haines conditions, but over a wide range of surface fire weather conditions. Statistically significant increases in the number of days where both C‐Haines and near‐surface fire weather values are conducive to pyroCb development are projected across southeastern Australia, predominantly for November (spring), and less strongly for December (summer) in 2060‐2079 versus 1990‐2009, with future C‐Haines increases linked to increased 850‐hPa dewpoint depression. The increased future occurrence of conditions conducive to pyroCb development and their extension into spring have implications for mitigating these dangerous wildfires and urbanizing fire‐prone landscapes.
Burning embers: towards more transparent and robust climate-change risk assessments
Publisher: Springer Science and Business Media LLC
Date: 10-09-2020
The Metaproteomics Initiative: a coordinated approach for propelling the functional characterization of microbiomes
Publisher: Springer Science and Business Media LLC
Date: 12-2021
DOI: 10.1186/S40168-021-01176-W
Abstract: Through connecting genomic and metabolic information, metaproteomics is an essential approach for understanding how microbiomes function in space and time. The international metaproteomics community is delighted to announce the launch of the Metaproteomics Initiative (www.metaproteomics.org), the goal of which is to promote dissemination of metaproteomics fundamentals, advancements, and applications through collaborative networking in microbiome research. The Initiative aims to be the central information hub and open meeting place where newcomers and experts interact to communicate, standardize, and accelerate experimental and bioinformatic methodologies in this field. We invite the entire microbiome community to join and discuss potential synergies at the interfaces with other disciplines, and to collectively promote innovative approaches to gain deeper insights into microbiome functions and dynamics.
The Impact of Observed Vegetation Changes on Land–Atmosphere Feedbacks During Drought
Publisher: American Meteorological Society
Date: 04-2014
Abstract: Moderate Resolution Imaging Spectroradiometer (MODIS)-derived vegetation fraction data were used to update the boundary conditions of the advanced research Weather Research and Forecasting (WRF) Model to assess the influence of realistic vegetation cover on climate simulations in southeast Australia for the period 2000–08. Results show that modeled air temperature was improved when MODIS data were incorporated, while precipitation changes little with only a small decrease in the bias. Air temperature changes in different seasons reflect the variability of vegetation cover well, while precipitation changes have a more complicated relationship to changes in vegetation fraction. Both MODIS and climatology-based simulation experiments capture the overall precipitation changes, indicating that precipitation is dominated by the large-scale circulation, with local vegetation changes contributing variations around these. Simulated feedbacks between vegetation fraction, soil moisture, and drought over southeast Australia were also investigated. Results indicate that vegetation fraction changes lag precipitation reductions by 6–8 months in nonarid regions. With the onset of the 2002 drought, a potential fast physical mechanism was found to play a positive role in the soil moisture–precipitation feedback, while a slow biological mechanism provides a negative feedback in the soil moisture–precipitation interaction on a longer time scale. That is, in the short term, a reduction in soil moisture leads to a reduction in the convective potential and, hence, precipitation, further reducing the soil moisture. If low levels of soil moisture persist long enough, reductions in vegetation cover and vigor occur, reducing the evapotranspiration and thus reducing the soil moisture decreases and d ening the fast physical feedback. Importantly, it was observed that these feedbacks are both space and time dependent.
Evaluating the Effectiveness of Mitigation Options on Heat Stress for Sydney, Australia
Publisher: American Meteorological Society
Date: 02-2018
Abstract: Global warming, in combination with the urban heat island effect, is increasing the temperature in cities. These changes increase the risk of heat stress for millions of city dwellers. Given the large populations at risk, a variety of mitigation strategies have been proposed to cool cities—including strategies that aim to reduce the ambient air temperature. This paper uses common heat stress metrics to evaluate the performance of several urban heat island mitigation strategies. The authors found that cooling via reducing net radiation or increasing irrigated vegetation in parks or on green roofs did reduce ambient air temperature. However, a lower air temperature did not necessarily lead to less heat stress because both temperature and humidity are important factors in determining human thermal comfort. Specifically, cooling the surface via evaporation through the use of irrigation increased humidity—consequently, the net impact on human comfort of any cooling was negligible. This result suggests that urban cooling strategies must aim to reduce ambient air temperatures without increasing humidity, for ex le via the deployment of solar panels over roofs or via cool roofs utilizing high albedos, in order to combat human heat stress in the urban environment.
First Emergence of Resistance to Macrolides and Tetracycline Identified in Mannheimia haemolytica and Pasteurella multocida Isolates from Beef Feedlots in Australia
Publisher: MDPI AG
Date: 17-06-2021
DOI: 10.3390/MICROORGANISMS9061322
Abstract: Bovine respiratory disease (BRD) causes high morbidity and mortality in beef cattle worldwide. Antimicrobial resistance (AMR) monitoring of BRD pathogens is critical to promote appropriate antimicrobial stewardship in veterinary medicine for optimal treatment and control. Here, the susceptibility of Mannheimia haemolytica and Pasteurella multicoda isolates obtained from BRD clinical cases (deep lung swabs at post-mortem) among feedlots in four Australian states (2014–2019) was determined for 19 antimicrobial agents. The M. haemolytica isolates were pan-susceptible to all tested agents apart from a single macrolide-resistant isolate (1/88 1.1%) from New South Wales (NSW). Much higher frequencies of P. multocida isolates were resistant to tetracycline (18/140 12.9%), tilmicosin (19/140 13.6%), tulathromycin/gamithromycin (17/140 12.1%), and icillin enicillin (6/140 4.6%). Five P. multocida isolates (3.6%), all obtained from NSW in 2019, exhibited dual resistance to macrolides and tetracycline, and a further two Queensland isolates from 2019 (1.4%) exhibited a multidrug-resistant phenotype to icillin enicillin, tetracycline, and tilmicosin. Random- lified polymorphic DNA (RAPD) typing identified a high degree of genetic homogeneity among the M. haemolytica isolates, whereas P. multocida isolates were more heterogeneous. Illumina whole genome sequencing identified the genes msr(E) and mph(E)encoding macrolide resistance, tet(R)-tet(H) or tet(Y) encoding tetracycline resistance, and blaROB-1 encoding icillin enicillin resistance in all isolates exhibiting a corresponding resistant phenotype. The exception was the tilmicosin-resistant, tulathromycin/gamithromycin-susceptible phenotype identified in two Queensland isolates, the genetic basis of which could not be determined. These results confirm the first emergence of AMR in M. haemolytica and P. multocida from BRD cases in Australia, which should be closely monitored.
Anthropogenic climate change has driven over 5 million km2 of drylands towards desertification
Publisher: Springer Science and Business Media LLC
Date: 31-07-2020
DOI: 10.1038/S41467-020-17710-7
Abstract: Drylands cover 41% of the earth’s land surface and include 45% of the world’s agricultural land. These regions are among the most vulnerable ecosystems to anthropogenic climate and land use change and are under threat of desertification. Understanding the roles of anthropogenic climate change, which includes the CO 2 fertilization effect, and land use in driving desertification is essential for effective policy responses but remains poorly quantified with methodological differences resulting in large variations in attribution. Here, we perform the first observation-based attribution study of desertification that accounts for climate change, climate variability, CO 2 fertilization as well as both the gradual and rapid ecosystem changes caused by land use. We found that, between 1982 and 2015, 6% of the world’s drylands underwent desertification driven by unsustainable land use practices compounded by anthropogenic climate change. Despite an average global greening, anthropogenic climate change has degraded 12.6% (5.43 million km 2 ) of drylands, contributing to desertification and affecting 213 million people, 93% of who live in developing economies.
How does bias correction of RCM precipitation affect modelled runoff?
Publisher: Copernicus GmbH
Date: 23-09-2014
DOI: 10.5194/HESSD-11-10683-2014
Abstract: Abstract. Many studies bias correct daily precipitation from climate models to match the observed precipitation statistics, and the bias corrected data are then used for various modelling applications. This paper presents a review of recent methods used to bias correct precipitation from regional climate models (RCMs). The paper then assesses four bias correction methods applied to the weather research and forecasting (WRF) model simulated precipitation, and the follow-on impact on modelled runoff for eight catchments in southeast Australia. Overall, the best results are produced by either quantile mapping or a newly proposed two-state gamma distribution mapping method. However, the difference between the tested methods is small in the modelling experiments here (and as reported in the literature), mainly because of the substantial corrections required and inconsistent errors over time (non-stationarity). The errors remaining in bias corrected precipitation are typically lified in modelled runoff. The tested methods cannot overcome limitation of RCM in simulating precipitation sequence, which affects runoff generation. Results further show that whereas bias correction does not seem to alter change signals in precipitation means, it can introduce additional uncertainty to change signals in high precipitation amounts and, consequently, in runoff. Future climate change impact studies need to take this into account when deciding whether to use raw or bias corrected RCM results. Nevertheless, RCMs will continue to improve and will become increasingly useful for hydrological applications as the bias in RCM simulations reduces.
Design of a regional climate modelling projection ensemble experiment - NARCliM
Publisher: Copernicus GmbH
Date: 16-04-2014
Abstract: Abstract. Including the impacts of climate change in decision making and planning processes is a challenge facing many regional governments including the New South Wales (NSW) and Australian Capital Territory (ACT) governments in Australia. NARCliM (NSW/ACT Regional Climate Modelling project) is a regional climate modelling project that aims to provide a comprehensive and consistent set of climate projections that can be used by all relevant government departments when considering climate change. To maximise end user engagement and ensure outputs are relevant to the planning process, a series of stakeholder workshops were run to define key aspects of the model experiment including spatial resolution, time slices, and output variables. As with all such experiments, practical considerations limit the number of ensemble members that can be simulated such that choices must be made concerning which global climate models (GCMs) to downscale from, and which regional climate models (RCMs) to downscale with. Here a methodology for making these choices is proposed that aims to s le the uncertainty in both GCM and RCM ensembles, as well as spanning the range of future climate projections present in the GCM ensemble. The RCM selection process uses performance evaluation metrics to eliminate poor performing models from consideration, followed by explicit consideration of model independence in order to retain as much information as possible in a small model subset. In addition to these two steps the GCM selection process also considers the future change in temperature and precipitation projected by each GCM. The final GCM selection is based on a subjective consideration of the GCM independence and future change. The created ensemble provides a more robust view of future regional climate changes. Future research is required to determine objective criteria that could replace the subjective aspects of the selection process.
Future Global Meteorological Drought Hot Spots: A Study Based on CORDEX Data
Publisher: American Meteorological Society
Date: 05-2020
Abstract: Two questions motivated this study: 1) Will meteorological droughts become more frequent and severe during the twenty-first century? 2) Given the projected global temperature rise, to what extent does the inclusion of temperature (in addition to precipitation) in drought indicators play a role in future meteorological droughts? To answer, we analyzed the changes in drought frequency, severity, and historically undocumented extreme droughts over 1981–2100, using the standardized precipitation index (SPI including precipitation only) and standardized precipitation-evapotranspiration index (SPEI indirectly including temperature), and under two representative concentration pathways (RCP4.5 and RCP8.5). As input data, we employed 103 high-resolution (0.44°) simulations from the Coordinated Regional Climate Downscaling Experiment (CORDEX), based on a combination of 16 global circulation models (GCMs) and 20 regional circulation models (RCMs). This is the first study on global drought projections including RCMs based on such a large ensemble of RCMs. Based on precipitation only, ~15% of the global land is likely to experience more frequent and severe droughts during 2071–2100 versus 1981–2010 for both scenarios. This increase is larger (~47% under RCP4.5, ~49% under RCP8.5) when precipitation and temperature are used. Both SPI and SPEI project more frequent and severe droughts, especially under RCP8.5, over southern South America, the Mediterranean region, southern Africa, southeastern China, Japan, and southern Australia. A decrease in drought is projected for high latitudes in Northern Hemisphere and Southeast Asia. If temperature is included, drought characteristics are projected to increase over North America, Amazonia, central Europe and Asia, the Horn of Africa, India, and central Australia if only precipitation is considered, they are found to decrease over those areas.
Changes in solar resource intermittency and reliability under Australia’s future warmer climate
Publisher: Elsevier BV
Date: 10-2023
Local and Remote Drivers of Southeast Australian Drought
Publisher: American Geophysical Union (AGU)
Date: 15-09-2020
DOI: 10.1029/2020GL090238
Abstract: Droughts are associated with large‐scale modes of variability, synoptic‐scale systems, and terrestrial processes. Quantifying their relative roles in influencing drought guides process understanding, helps identify weaknesses in climate models, and focuses model improvements. Using a Lagrangian back‐trajectory approach we provide the first quantification of the change in moisture supply during major droughts in southeast Australia, including the causes of the changes. Drought onset and intensification were driven by reduced moisture supply from the ocean, as moisture was circulated away from the region, combined with an absence of precipitation‐generating mechanisms over land. During termination, strengthened moist easterly flows from the Tasman and Coral Seas promoted anomalously high rainfall. Our approach reveals terrestrial moisture sources played a secondary role, lifying rainfall anomalies by less than 6%. Simulating droughts therefore requires deeper understanding of the relationship between moisture advection and synoptic‐scale circulation and how large‐scale climate variability and terrestrial processes modify these relationships.
Recent reversal in loss of global terrestrial biomass
Publisher: Springer Science and Business Media LLC
Date: 30-03-2015
DOI: 10.1038/NCLIMATE2581
Influence of reanalysis datasets on dynamically downscaling the recent past
Publisher: Springer Science and Business Media LLC
Date: 05-10-2017
Corrigendum to "Implementation of a soil albedo scheme in the CABLEv1.4b land surface model and evaluation against MODIS estimates over Australia" published in Geosci. Model Dev., 7,
Publisher: Copernicus GmbH
Date: 28-10-2014
A comparison of methods for estimating climate change impact on design rainfall using a high-resolution RCM
Publisher: Elsevier BV
Date: 04-2017
Assessing the impact of model spin-up on surface water-groundwater interactions using an integrated hydrologic model
Publisher: American Geophysical Union (AGU)
Date: 03-2014
DOI: 10.1002/2013WR014258
Drivers of future water demand in Sydney, Australia: examining the contribution from population and climate change
Publisher: IWA Publishing
Date: 07-08-2020
DOI: 10.2166/WCC.2020.230
Abstract: We examine the relative impact of population increases and climate change in affecting future water demand for Sydney, Australia. We use the Weather and Research Forecasting model, a water demand model and a stochastic weather generator to downscale four different global climate models for the present (1990–2010), near (2020–2040) and far (2060–2080) future. Projected climate change would increase median metered consumption, at 2019/2020 population levels, from around 484 GL under present climate to 484–494 GL under near future climate and 495–505 GL under far future climate. Population changes from 2014/2015 to 2024/2025 have a far larger impact, increasing median metered consumption from 457 to 508 GL under the present climate, 463 to 515 GL under near future climate and from 471 to 524 GL under far future climate. The projected changes in consumption are sensitive to the climate model used. Overall, while population growth is a far stronger driver of increasing water demand than climate change for Sydney, both act in parallel to reduce the time it would take for all storage to be exhausted. Failing to account for climate change would therefore lead to overconfidence in the reliability of Sydney's water supply.
Estimation of future changes in photovoltaic potential in Australia due to climate change
Publisher: IOP Publishing
Date: 11-2021
Abstract: Solar photovoltaic (PV) energy is one of the fastest growing renewable energy sources globally. However, the dependency of PV generation on climatological factors such as the intensity of radiation, temperature, wind speed, cloud cover, etc can impact future power generation capacity. Considering the future large-scale deployment of PV systems, accurate climate information is essential for PV site selection, stable grid regulation, planning and energy output projections. In this study, the long-term changes in the future PV potential are estimated over Australia using regional climate projections for the near-future (2020–2039) and far-future (2060–2079) periods under a high emission scenario that projects 3.4 °C warming by 2100. The effects of projected changes in shortwave downwelling radiation, temperature and wind speed on the future performance of PV systems over Australia is also examined. Results indicate decline in the future PV potential over most of the continent due to reduced insolation and increased temperature. Northern coastal Australia experiences negligible increase in PV potential during the far future period due to increase in radiation and wind speed in that region. On further investigation, we find that the cell temperatures are projected to increase in the future under a high emission scenario (2.5 °C by 2079), resulting in increased degradation and risks of failure. The elevated cell temperatures significantly contribute to cell efficiency losses, that are expected to increase in the future (6–13 d yr −1 for multi-crystalline silicon cells) mostly around Western and central Australia indicating further reductions in PV power generation. Therefore, long-term PV power projections can help understand the variations in future power generation and identify regions where PV systems will be highly susceptible to losses in Australia.
An object-based climatology of precipitation systems in Sydney, Australia
Publisher: Springer Science and Business Media LLC
Date: 14-07-2023
DOI: 10.1007/S00382-022-06404-Z
Abstract: The climate is warming and this is changing some aspects of storms, but we have relatively little knowledge of storm characteristics beyond intensity, which limits our understanding of storms overall. In this study, we apply a cell-tracking algorithm to 20 years of radar data at a mid-latitude coastal-site (Sydney, Australia), to establish a regional precipitation system climatology. The results show that extreme storms in terms of translation-speed, size and rainfall intensity usually occur in the warm season, and are slower and more intense over land between ~ 10 am and ~ 8 pm (AEST), peaking in the afternoon. Precipitation systems are more frequent in the cold season and often initiate over the ocean and move northward, leading to precipitation mostly over the ocean. Using clustering algorithms, we have found five precipitation system types with distinct properties, occurring throughout the year but peaking in different seasons. While overall rainfall statistics don't show any link to climate modes, links do appear for some system types using a multivariate approach. This climatology for a variety of precipitation system characteristics will allow future study of any changes in these characteristics due to climate change.
Impact of bias-corrected RCM lateral boundary conditions on precipitation extremes
Publisher: Copernicus GmbH
Date: 23-09-2022
DOI: 10.5194/IAHS2022-312
Abstract: & & Hydro-climatological applications often require global climate models (GCMs) outputs to assess the impacts of climate change. However, it is well known that the direct use of GCM simulations is limited as their spatial and temporal resolution are insufficient to provide output at the regional scale required in assessing changes in extreme rainfall. Although regional climate models (RCMs) forced with GCM data are widely used to resolve finer resolutions, their application is hindered by systematic biases contained in large-scale circulation patterns from driving GCM data. To deal with these considerable biases, recent studies have suggested the bias correction of the input boundary conditions of RCM.& & & & This study focuses on the impact of bias corrections in the input boundary conditions of RCM on extreme rainfall events. Three bias correction methods are used: mean, mean and variance, and nested bias correction (NBC) that corrects lag-1 autocorrelations. RCM used here is the Weather Research and Forecasting model (WRF), and the European Center for Medium-Range Weather Forecast& #8217 s (ECMWF) ERA-Interim (ERA-I) reanalysis model is used as an & #8220 observational& #8221 reference for bias correction. The downscaling is performed over the Australasian Coordinated Regional Climate Downscaling Experiment (CORDEX) domain.& & & & Two quantitative measures are used to evaluate the impact of bias correction on the RCM output: root-mean-square errors (RMSE) and bias. Indices from the World Meteorological Organization (WMO) Expert Team on Climate Risk and Sectoral Climate Indicators (ET-CRSCI) are used to evaluate bias correction performance on extreme rainfall.& & & & It is clear from the statistics used here that bias correction on the input boundary condition produces a noticeable improvement in daily precipitation percentile indices. The results also show that the sophisticated method representing rainfall variability and long-term persistence corrects details in simulating extreme rainfall.& &
A lipoglycopeptide antibiotic for Gram-positive biofilm-related infections
Publisher: American Association for the Advancement of Science (AAAS)
Date: 14-09-2022
DOI: 10.1126/SCITRANSLMED.ABJ2381
Abstract: Drug-resistant Gram-positive bacterial infections are still a substantial burden on the public health system, with two bacteria ( Staphylococcus aureus and Streptococcus pneumoniae ) accounting for over 1.5 million drug-resistant infections in the United States alone in 2017. In 2019, 250,000 deaths were attributed to these pathogens globally. We have developed a preclinical glycopeptide antibiotic, MCC5145, that has excellent potency (MIC 90 ≤ 0.06 μg/ml) against hundreds of isolates of methicillin-resistant S. aureus (MRSA) and other Gram-positive bacteria, with a greater than 1000-fold margin over mammalian cell cytotoxicity values. The antibiotic has therapeutic in vivo efficacy when dosed subcutaneously in multiple murine models of established bacterial infections, including thigh infection with MRSA and blood septicemia with S. pneumoniae , as well as when dosed orally in an antibiotic-induced Clostridioides difficile infection model. MCC5145 exhibited reduced nephrotoxicity at microbiologically active doses in mice compared to vancomycin. MCC5145 also showed improved activity against biofilms compared to vancomycin, both in vitro and in vivo, and a low propensity to select for drug resistance. Characterization of drug action using a transposon library bioinformatic platform showed a mechanistic distinction from other glycopeptide antibiotics.
Estimating Grassland Curing with Remotely Sensed Data
Publisher: Copernicus GmbH
Date: 11-04-2017
Abstract: Abstract. Wildfire can become a catastrophic natural hazard, especially during dry summer seasons in Australia. Severity is influenced by various meteorological, geographical, and fuel characteristics. Modified Mark 4 McArthur's Grassland Fire 10 Danger Index (GFDI) is a commonly used approach to determine the fire danger level in grassland ecosystems. The degree of curing (DOC, i.e. proportion of dead material) of the grass is one key ingredient in determining the fire danger. It is difficult to collect accurate DOC information in the field, therefore, ground observed measurements are rather limited. In this study, we used satellite observed vegetation greenness (Normalised Difference Vegetation Index, NDVI) and vegetation water content (Vegetation Optical Depth, VOD) information to improve the accuracy of the DOC estimation. First, a statistically 15 significant relationship is established between selected ground observed DOC and satellite observed vegetation datasets (NDVI and VOD) with an r2 of 0.67. DOC levels estimated using satellite observations were then evaluated using field measurements with an r2 of 0.55. Results suggest that satellite based DOC estimation can reasonably reproduce ground based observations in space and time. Comparison with currently available satellite based DOC products shows that our model has a comparable and arguably more balanced performance.
Derived Optimal Linear Combination Evapotranspiration (DOLCE): a global gridded synthesis ET estimate
Publisher: Copernicus GmbH
Date: 03-04-2017
Abstract: Abstract. Accurate global gridded estimates of evapotranspiration (ET) are key to understanding water and energy budgets, as well as being required for model evaluation. Several gridded ET products have already been developed which differ in their data requirements, the approaches used to derive them and their estimates, yet it is not clear which provides the most reliable estimates. This paper presents a new global ET dataset and associated uncertainty with monthly temporal resolution for 2000–2009. Six existing gridded ET products are combined using a weighting approach trained by observational datasets from 159 FLUXNET sites. The weighting method is based on a technique that provides an analytically optimal linear combination of ET products compared to site data, and accounts for both the performance differences and error covariance between the participating ET products. We examine the performance of the weighting approach in several in-s le and out-of-s le tests that confirm that point-based estimates of flux towers provide information at the grid scale of these products. We also provide evidence that the weighted product performs better than its six constituent ET product members in three common metrics. Uncertainty in the ET estimate is derived by rescaling the spread of participating ET products so that their spread reflects the ability of the weighted mean estimate to match flux tower data. While issues in observational data and any common biases in participating ET datasets are limitations to the success of this approach, future datasets can easily be incorporated and enhance the derived product.
A regional climate modelling projection ensemble experiment – NARCliM
Publisher: Copernicus GmbH
Date: 25-09-2013
Abstract: Abstract. Including the impacts of climate change in decision making and planning processes is a challenge facing many regional governments including the New South Wales (NSW) and Australian Capital Territory (ACT) governments in Australia. NARCliM (NSW/ACT Regional Climate Modelling project) is a regional climate modelling project that aims to provide a comprehensive and consistent set of climate projections that can be used by all relevant government departments when considering climate change. To maximise end user engagement and ensure outputs are relevant to the planning process, a series of stakeholder workshops were run to define key aspects of the model experiment including spatial resolution, time slices, and output variables. As with all such experiments, practical considerations limit the number of ensembles members that can be simulated such that choices must be made concerning which Global Climate Models (GCMs) to downscale from, and which Regional Climate Models (RCMs) to downscale with. Here a methodology for making these choices is proposed that aims to s le the uncertainty in both GCMs and RCMs, as well as spanning the range of future climate projections present in the full GCM ensemble. The created ensemble provides a more robust view of future regional climate changes.
Supplementary material to "Technical Note: Reducing the spin-up time of integrated surface water–groundwater models"
Publisher: Copernicus GmbH
Date: 26-06-2014
The Worldwide C3S CORDEX Grand Ensemble: A Major Contribution to Assess Regional Climate Change in the IPCC AR6 Atlas
Publisher: American Meteorological Society
Date: 12-2022
Abstract: The collaboration between the Coordinated Regional Climate Downscaling Experiment (CORDEX) and the Earth System Grid Federation (ESGF) provides open access to an unprecedented ensemble of regional climate model (RCM) simulations, across the 14 CORDEX continental-scale domains, with global coverage. These simulations have been used as a new line of evidence to assess regional climate projections in the latest contribution of the Working Group I (WGI) to the IPCC Sixth Assessment Report (AR6), particularly in the regional chapters and the Atlas. Here, we present the work done in the framework of the Copernicus Climate Change Service (C3S) to assemble a consistent worldwide CORDEX grand ensemble, aligned with the deadlines and activities of IPCC AR6. This work addressed the uneven and heterogeneous availability of CORDEX ESGF data by supporting publication in CORDEX domains with few archived simulations and performing quality control. It also addressed the lack of comprehensive documentation by compiling information from all contributing regional models, allowing for an informed use of data. In addition to presenting the worldwide CORDEX dataset, we assess here its consistency for precipitation and temperature by comparing climate change signals in regions with overlapping CORDEX domains, obtaining overall coincident regional climate change signals. The C3S CORDEX dataset has been used for the assessment of regional climate change in the IPCC AR6 (and for the interactive Atlas) and is available through the Copernicus Climate Data Store (CDS).
Pneumococcal Virulence Gene Expression and Host Cytokine Profiles during Pathogenesis of Invasive Disease
Publisher: American Society for Microbiology
Date: 02-2008
DOI: 10.1128/IAI.01161-07
Abstract: Pneumococcal disease continues to account for significant morbidity and mortality worldwide. For the development of novel prophylactic and therapeutic strategies against the disease spectrum, a complete understanding of pneumococcal behavior in vivo is necessary. We evaluated the expression patterns of the proven and putative virulence factor genes adcR , cbpA , cbpD , cbpG , cpsA , nanA , pcpA , piaA , ply , psaA , pspA , and spxB after intranasal infection of CD1 mice with serotype 2, 4, and 6A pneumococci by real-time reverse transcription-PCR. Simultaneous gene expression patterns of selected host immunomodulatory molecules, CCL2, CCL5, CD54, CXCL2, interleukin-6, and tomor necrosis factor alpha, were also investigated. We show that pneumococcal virulence genes are differentially expressed in vivo, with some genes demonstrating niche- and serotype-specific differential expression. The in vivo expression patterns could not be attributed to in vitro differences in expression of the genes in transparent and opaque variants of the three strains. The host molecules were significantly upregulated, especially in the lungs, blood, and brains of mice. The pneumococcal-gene expression patterns support their ascribed roles in pathogenesis, providing insight into which protein combinations might be more appropriate as vaccine antigens against invasive disease. This is the first simultaneous comparison of bacterial- and host gene expression in the same animal during pathogenesis. The strategy provides a platform for prospective evaluation of interaction kinetics between invading pneumococci and human patients in culture-positive cases and should be feasible in other infection models.
Strong intensification of hourly rainfall extremes by urbanization
Publisher: Wiley
Date: 04-09-2020
The Role of Low-Level, Terrain-Induced Jets in Rainfall Variability in Tigris–Euphrates Headwaters
Publisher: American Meteorological Society
Date: 03-2017
Abstract: Rainfall variability in the Tigris–Euphrates headwaters is a result of interaction between topography and meteorological features at a range of spatial scales. Here, the Weather Research and Forecasting (WRF) Model, driven by the NCEP–DOE AMIP-II reanalysis (R-2), has been implemented to better understand these interactions. Simulations were performed over a domain covering most of the Middle East. The extended simulation period (1983–2013) enables us to study seasonality, interannual variability, spatial variability, and extreme events of rainfall. Results showed that the annual cycle of precipitation produced by WRF agrees much more closely with observations than does R-2. This was particularly evident during the transition months of April and October, which were further examined to study the underlying physical mechanisms. In both months, WRF improves representation of interannual variability relative to R-2, with a substantially larger benefit in April. This improvement results primarily from WRF’s ability to resolve two low-level, terrain-induced flows in the region that are either absent or weak in R-2: one parallel to the western edge of the Zagros Mountains, and one along the east Turkish highlands. The first shows a complete reversal in its direction during wet and dry days: when flowing southeasterly it transports moisture from the Persian Gulf to the region, and when flowing northwesterly it blocks moisture and transports it away from the region. The second is more directly related to synoptic-scale systems and carries moist, warm air from the Mediterranean and Red Seas toward the region. The combined contribution of these flows explains about 50% of interannual variability in both WRF and observations for April and October precipitation.
Effects of spatial aggregation on the multi-scale estimation of evapotranspiration
Publisher: Elsevier BV
Date: 04-2013
North Atlantic observations sharpen meridional overturning projections
Publisher: Springer Science and Business Media LLC
Date: 23-08-2017
Contrasting Regional Responses to Increasing Leaf-Level Atmospheric Carbon Dioxide over Australia
Publisher: American Meteorological Society
Date: 04-2010
Abstract: Using a coupled atmosphere–land surface model, simulations were conducted to characterize the regional climate changes that result from the response of stomates to increases in leaf-level carbon dioxide (CO2) under differing conditions of moisture availability over Australia. Multiple realizations for multiple Januarys corresponding to dry and wet years were run, where only the leaf-level CO2 was varied at 280, 375, 500, 650, 840, and 1000 ppmv and the atmospheric CO2 was fixed at 375 ppmv. The results show the clear effect of increasing leaf-level CO2 on the transpiration via the stomatal response, particularly when sufficient moisture is available. Statistically significant reductions in transpiration generally lead to a significantly warmer land surface with decreases in rainfall. Increases in CO2 lead to increases in the magnitude and areal extent of the statistically significant mean changes in the surface climate. However, the results also show that the availability of moisture substantially affects the effect of increases in the leaf-level CO2, particularly for a moisture-limited region. The physiological feedback can indirectly lead to more rainfall via changes in the low-level moisture convergence and vertical velocity, which result in a cooling simulated over Western Australia. The significant changes in the surface climate presented in the results suggest that it is still important to incorporate these feedbacks in future climate assessments and projections for Australia. The influence of moisture availability also indicates that the capacity of the physiological feedback to affect the future climate may be affected by uncertainties in rainfall projections, particularly for water-stressed regions such as Australia.
A functional genomics catalogue of activated transcription factors during pathogenesis of pneumococcal disease
Publisher: Springer Science and Business Media LLC
Date: 08-09-2014
Weather Types and Hourly to Multiday Rainfall Characteristics in Tropical Australia
Publisher: American Meteorological Society
Date: 14-06-2019
Abstract: Six weather types (WTs) are computed for tropical Australia during the wet season (November–March 1979–2015) using cluster analysis of 6-hourly low-level winds at 850 hPa. The WTs may be interpreted as a varying combination of at least five distinct phenomena operating at different time scales: the diurnal cycle, fast and recurrent atmospheric phenomena such as transient low pressure, the intraseasonal Madden–Julian oscillation, the annual cycle, and interannual variations mostly associated with El Niño–Southern Oscillation. The WTs are also strongly phase-locked onto the break/active phases of the monsoon two WTs characterize mostly the trade-wind regime prevalent either at the start and the end of the monsoon or during its breaks, while three monsoonal WTs occur mostly during its core and active phases. The WT influence is strongest for the frequency of wet spells, while the influence on intensity varies according to the temporal aggregation of the rainfall. At hourly time scale, the climatological mean wet intensity tends to be near-constant in space and not systematically larger for the monsoonal WTs compared to other WTs. Nevertheless, one transitional WT, most prevalent around late November and characterized by weak synoptic forcings and overall drier conditions than the monsoonal WTs, is associated with an increased number of high hourly rainfall intensities for some stations, including for the interior of the Cape York Peninsula. When the temporal aggregation exceeds 6–12 h, the mean intensity tends to be larger for some of the monsoonal WTs, in association with more frequent and also slightly longer wet spells.
Publisher Correction: Global hotspots for the occurrence of compound events
Publisher: Springer Science and Business Media LLC
Date: 18-12-2020
DOI: 10.1038/S41467-020-20502-8
Abstract: A Correction to this paper has been published: 0.1038/s41467-020-20502-8.
A CMIP6-based multi-model downscaling ensemble to underpin climate change services in Australia
Publisher: Elsevier BV
Date: 04-2023
The role of topography on projected rainfall change in mid-latitude mountain regions
Publisher: Springer Science and Business Media LLC
Date: 22-03-2019
Toward a Robust, Impact‐Based, Predictive Drought Metric
Publisher: American Geophysical Union (AGU)
Date: 02-2022
DOI: 10.1029/2021WR031829
Abstract: This work presents a new approach to defining drought by establishing an empirical relationship between historical droughts (and wet spells) documented in impact reports, and a broad range of observed climate features using Random Forest (RF) models. The new drought indicator quantifies the conditional probability of drought, considering multiple drought‐related climate features and their interactive effects, and can be used for forecasting with up to 3‐month lead time. The approach was tested out‐of‐s le across several random selections of training and testing datasets, and demonstrated better predictive capabilities than commonly used drought indicators (e.g., Standardised Precipitation Index and Evaporative Demand Drought Index) in a range of performance metrics. Furthermore, it showed comparable performance to the (expert elicitation‐based) US Drought Monitor (USDM), the current state‐of‐the‐art record of historical drought in the USA. As well as providing an alternative historical drought indicator to USDM, the RF approach offers additional advantages by being automated, by providing drought information at the grid‐scale, and by having forecasting capacity. While traditional drought metrics define drought as extreme anomalies in drought‐related variables, the approach presented here reveals the full suite of circumstances that lead to impactful droughts. We highlight several combinations of climate features—such as precipitation, potential evapotranspiration, soil moisture and change in water storage—that led to drought events not detected by commonly used drought metrics. The new RF drought indicator combines meteorological, hydrological, agricultural, and socioeconomic drought, providing drought information for all impacted sectors. As a proof‐of‐concept, the RF drought indicator was trained on Texan climate data and droughts.
Precipitation bias correction of very high resolution regional climate models
Publisher: Copernicus GmbH
Date: 25-06-2013
DOI: 10.5194/HESSD-10-8145-2013
Abstract: Abstract. Regional climate models are prone to biases in precipitation that are problematic for use in impact models such as hydrology models. A large number of methods have already been proposed aimed at correcting various moments of the rainfall distribution. They all require that the model produce the same or a higher number of rain days than the observational datasets, which are usually gridded datasets. Models have traditionally met this condition because their spatial resolution was coarser than the observational grids. But recent climate simulations use higher resolution than the gridded observational products and the models are likely to produce fewer rain days than the gridded observations. In this study, model output from a simulation at 2 km resolution are compared with gridded and in-situ observational datasets to determine whether the new scenario calls for revised methodologies. The gridded observations are found to be inadequate to correct the high-resolution model at daily timescales. A histogram equalisation bias correction method is selected and adapted to the use of stations, alleviating the problems associated with relatively low-resolution observational grids. The method is efficient at bias correcting both seasonal and daily characteristics of precipitation, providing more accurate information that is crucial for impact assessment studies.
Summertime maximum and minimum temperature coupling asymmetry over Australia determined using WRF
Publisher: American Geophysical Union (AGU)
Date: 05-03-2014
DOI: 10.1002/2013GL059055
Evaluating rainfall patterns using physics scheme ensembles from a regional atmospheric model
Publisher: Springer Science and Business Media LLC
Date: 23-04-2013
Comparative GO: A Web Application for Comparative Gene Ontology and Gene Ontology-Based Gene Selection in Bacteria
Publisher: Public Library of Science (PLoS)
Date: 11-03-2013
Enhanced canopy growth precedes senescence in 2005 and 2010 Amazonian droughts
Publisher: Elsevier BV
Date: 06-2018
The terminal-velocity assumption in simulations of long-range ember transport
Publisher: Elsevier BV
Date: 09-2020
The Pneumococcal Alpha-Glycerophosphate Oxidase Enhances Nasopharyngeal Colonization through Binding to Host Glycoconjugates.
Publisher: Elsevier BV
Date: 04-2017
A Transcription Factor Contributes to Pathogenesis and Virulence in Streptococcus pneumoniae
Publisher: Public Library of Science (PLoS)
Date: 13-08-2013
On the non-stationarity of hydrological response in anthropogenically unaffected catchments: An Australian perspective
Publisher: Copernicus GmbH
Date: 29-07-2016
Abstract: Abstract. Increases in greenhouse gas concentrations are expected to impact the terrestrial hydrologic cycle through changes in radiative forcings and plant physiological and structural responses. Here we investigate the nature and frequency of non-stationary hydrological response as evidenced through water balance studies over 166 anthropogenically unaffected catchments in Australia. Non-stationarity of hydrologic response is investigated through analysis of long term trend in annual runoff ratio (1984–2005). Results indicate that a significant trend (p
Spatial and temporal variability in seasonal snow density
Publisher: Elsevier BV
Date: 03-2013
Technical Note: Reducing the spin-up time of integrated surface water–groundwater models
Publisher: Copernicus GmbH
Date: 12-12-2014
DOI: 10.5194/HESS-18-5169-2014
Abstract: Abstract. One of the main challenges in the application of coupled or integrated hydrologic models is specifying a catchment's initial conditions in terms of soil moisture and depth-to-water table (DTWT) distributions. One approach to reducing uncertainty in model initialization is to run the model recursively using either a single year or multiple years of forcing data until the system equilibrates with respect to state and diagnostic variables. However, such "spin-up" approaches often require many years of simulations, making them computationally intensive. In this study, a new hybrid approach was developed to reduce the computational burden of the spin-up procedure by using a combination of model simulations and an empirical DTWT function. The methodology is examined across two distinct catchments located in a temperate region of Denmark and a semi-arid region of Australia. Our results illustrate that the hybrid approach reduced the spin-up period required for an integrated groundwater–surface water–land surface model (ParFlow.CLM) by up to 50%. To generalize results to different climate and catchment conditions, we outline a methodology that is applicable to other coupled or integrated modeling frameworks when initialization from an equilibrium state is required.
Changes in water vapor transport and the production of precipitation in the eastern fertile crescent as a result of global warming
Publisher: American Meteorological Society
Date: 12-2008
DOI: 10.1175/2008JHM998.1
Abstract: This study investigates changes in the types of storm events occurring in the Fertile Crescent as a result of global warming. Regional climate model [fifth-generation Pennsylvania State University–National Center for Atmospheric Research Mesoscale Model (MM5)–Noah] simulations are run for the first and last five years of the twenty-first century following the Special Report on Emissions Scenarios (SRES) A2 experiment. Then the precipitation events are classified according to the water vapor fluxes that created them. At present most of the region’s precipitation is from westerly water vapor fluxes. Results indicate that the region will increasingly get its precipitation from large events that are dominated by southerly water vapor fluxes. The increase in these events will occur in the transition seasons, especially autumn.
Biases in estimating long-term recurrence intervals of extreme events due to regionalised sampling
Publisher: Authorea, Inc.
Date: 09-03-2023
DOI: 10.22541/ESSOAR.167839988.80634934/V1
Abstract: Preparing for environmental risks requires estimating the frequencies of extreme events, often from data records that are too short to confirm them directly. This requires fitting a statistical distribution to the data. To improve precision, investigators often pool data from neighboring sites into single s les, referred to as “superstations,” before fitting. We demonstrate that this technique can introduce unexpected biases in typical situations, using wind and rainfall extremes as case studies. When the combined locations have even small differences in the underlying statistics, the regionalization approach gives a fit that may tend toward the highest levels suggested by any of the in idual sites. This bias may be large or small compared to the s ling error, for realistic record lengths, depending on the distribution of the quantity analysed. The results of this analysis indicate that previous analyses could potentially have overestimated the likelihood of extreme events arising from natural weather variability.
The influence of local sea surface temperatures on Australian east coast cyclones
Publisher: American Geophysical Union (AGU)
Date: 25-11-2016
DOI: 10.1002/2016JD025495
Detecting dryland degradation using Time Series Segmentation and Residual Trend analysis (TSS-RESTREND)
Publisher: Elsevier BV
Date: 08-2017
Classifying rangeland vegetation type and coverage using a Fourier component based similarity measure
Publisher: Elsevier BV
Date: 15-11-2006
A Bayesian analysis of sensible heat flux estimation: Quantifying uncertainty in meteorological forcing to improve model prediction
Publisher: American Geophysical Union (AGU)
Date: 05-2013
DOI: 10.1002/WRCR.20231
Time series analysis of regional climate model performance
Publisher: American Geophysical Union (AGU)
Date: 2005
DOI: 10.1029/2004JD005046
Supplementary material to "How does bias correction of RCM precipitation affect modelled runoff?"
Publisher: Copernicus GmbH
Date: 23-09-2014
Supplementary material to "Robust historical evapotranspiration trends across climate regimes"
Publisher: Copernicus GmbH
Date: 09-12-2020
Classifying rangeland vegetation type and coverage from NDVI time series using Fourier Filtered Cycle Similarity
Publisher: Informa UK Limited
Date: 20-12-2005
A systematic review of climate change science relevant to Australian design flood estimation
Publisher: Copernicus GmbH
Date: 10-10-2023
The influence of topography on midlatitude cyclones on Australia's east coast
Publisher: American Geophysical Union (AGU)
Date: 07-09-2017
DOI: 10.1002/2017JD027345
Changing Climate and Overgrazing Are Decimating Mongolian Steppes
Publisher: Public Library of Science (PLoS)
Date: 25-02-2013
Conserving Land–Atmosphere Synthesis Suite (CLASS)
Publisher: American Meteorological Society
Date: 03-2020
Abstract: Accurate estimates of terrestrial water and energy cycle components are needed to better understand climate processes and improve models’ ability to simulate future change. Various observational estimates are available for the in idual budget terms however, these typically show inconsistencies when combined in a budget. In this work, a Conserving Land–Atmosphere Synthesis Suite (CLASS) of estimates of simultaneously balanced surface water and energy budget components is developed. In idual CLASS variable datasets, where possible, 1) combine a range of existing variable product estimates, and hence overcome the limitations of estimates from a single source 2) are observationally constrained with in situ measurements 3) have uncertainty estimates that are consistent with their agreement with in situ observations and 4) are consistent with each other by being able to solve the water and energy budgets simultaneously. First, available datasets of a budget variable are merged by implementing a weighting method that accounts both for the ability of datasets to match in situ measurements and the error covariance between datasets. Then, the budget terms are adjusted by applying an objective variational data assimilation technique (DAT) that enforces the simultaneous closure of the surface water and energy budgets linked through the equivalence of evapotranspiration and latent heat. Comparing component estimates before and after applying the DAT against in situ measurements of energy fluxes and streamflow showed that modified estimates agree better with in situ observations across various metrics, but also revealed some inconsistencies between water budget terms in June over the higher latitudes. CLASS variable estimates are freely available via 0.25914/5c872258dc183 .
A COL17A1 Splice-Altering Mutation Is Prevalent in Inherited Recurrent Corneal Erosions
Publisher: Elsevier BV
Date: 04-2016
DOI: 10.1016/J.OPHTHA.2015.12.008
Abstract: Corneal dystrophies are a genetically heterogeneous group of disorders. We previously described a family with an autosomal dominant epithelial recurrent erosion dystrophy (ERED). We aimed to identify the underlying genetic cause of ERED in this family and 3 additional ERED families. We sought to characterize the potential function of the candidate genes using the human and zebrafish cornea. Case series study of 4 white families with a similar ERED. An experimental study was performed on human and zebrafish tissue to examine the putative biological function of candidate genes. Four ERED families, including 28 affected and 17 unaffected in iduals. HumanLinkage-12 arrays (Illumina, San Diego, CA) were used to genotype 17 family members. Next-generation exome sequencing was performed on an uncle-niece pair. Segregation of potential causative mutations was confirmed using Sanger sequencing. Protein expression was determined using immunohistochemistry in human and zebrafish cornea. Gene expression in zebrafish was assessed using whole-mount in situ hybridization. Morpholino-induced transient gene knockdown was performed in zebrafish embryos. Linkage microarray, exome analysis, DNA sequence analysis, immunohistochemistry, in situ hybridization, and morpholino-induced genetic knockdown results. Linkage microarray analysis identified a candidate region on chromosome chr10:12,576,562-112,763,135, and exploration of exome sequencing data identified 8 putative pathogenic variants in this linkage region. Two variants segregated in 06NZ-TRB1 with ERED: COL17A1 c.3156C→T and DNAJC9 c.334G→A. The COL17A1 c.3156C→T variant segregated in all 4 ERED families. We showed biologically relevant expression of these proteins in human cornea. Both proteins are expressed in the cornea of zebrafish embryos and adults. Zebrafish lacking Col17a1a and Dnajc9 during development show no gross corneal phenotype. The COL17A1 c.3156C→T variant is the likely causative mutation in our recurrent corneal erosion families, and its presence in 4 independent families suggests that it is prevalent in ERED. This same COL17A1 c.3156C→T variant recently was identified in a separate pedigree with ERED. Our study expands the phenotypic spectrum of COL17A1 disease from autosomal recessive epidermolysis bullosa to autosomal dominant ERED and identifies COL17A1 as a key protein in maintaining integrity of the corneal epithelium.
Introducing NARCliM1.5: Evaluating the Performance of Regional Climate Projections for Southeast Australia for 1950–2100
Publisher: American Geophysical Union (AGU)
Date: 07-2021
DOI: 10.1029/2020EF001833
Abstract: The NARCliM project contributes to the CORDEX initiative for Australasia. The first generation of NARCliM (N1.0) used CMIP3 global climate models (GCMs) and provided near and far future estimates of climate change across Australasia at 50‐km and southeast Australia at 10‐km resolution under a business‐as‐usual climate scenario. However, multiple sets of 20‐year periods in N1.0 did not permit analysis of long‐term, inter‐annual to decadal trends across the 21st century. Feedback on user needs for regional climate information revealed the desire for multiple emission scenarios and use of newer CMIP5 GCMs for dynamical downscaling. These limitations led to development of the second iteration of NARCliM, namely NARCliM1.5 (N1.5). The N1.5 downscaling exercise uses CMIP5 GCMs and is temporally expanded to cover 150 years (1950–2100) for two future Representative Concentration Pathways (RCP4.5 and RCP8.5). N1.5 simulations remain at the 50‐km and 10 km resolutions over the same domains as N1.0, thus producing an expanded and complementary data set for regional climate change. N1.5 simulations substantially improve over N1.0 in capturing the seasonal patterns and magnitudes of precipitation, including improvements in overall bias. Conversely, N1.5 shows similar results to N1.0 for maximum and minimum temperature, with no substantial improvement in overall bias. N1.5 projections project a hotter and drier future relative to N1.0. The combined N1.0 and N1.5 ensemble provides a wider spread of future climates more representative of that found in the full CMIP5 ensemble. Together, N1.0 and N1.5 ensembles provide an improved, more comprehensive data set for studying climate change.
Future Regional Climates
Publisher: Elsevier
Date: 2012
Regional impact of an elevated heat source: The Zagros Plateau of Iran
Publisher: American Meteorological Society
Date: 15-08-2007
DOI: 10.1175/JCLI4248.1
Abstract: The authors propose that a heat-driven circulation from the Zagros Plateau has a significant impact on the climate of the Middle East Plain (MEP), especially summertime winds, air temperature, and aridity. This proposal is examined in numerical experiments with a regional climate model. Simulations in which the Zagros Plateau was assigned a highly reflective, “snowlike” albedo neutralized the heat-driven circulation and produced an extra summertime warming of 1°–2°C in the MEP, measured relative to a control simulation and to the records of the NCEP–NCAR reanalysis project. This effect was largest in midsummer, when heating on the plateau was greatest. Additionally, simulations with high albedo on the Zagros showed reduced subsidence and enhanced precipitation in the MEP. These sensitivities are interesting because the Zagros Plateau lies downwind of the MEP. Analysis of model results indicates that the sensitivity of the upwind subsidence region to Zagros albedo can be understood as a linear atmospheric response to plateau heating, communicated upwind by a steady heat-driven circulation that influences the thermodynamic balance of the atmosphere. This regional phenomenon adds to the large-scale subsidence patterns established by the Hadley circulation and the Asian monsoon. Observed patterns of vertical motion in the Middle East, then, are a combined product of Zagros-induced subsidence and hemispheric-scale circulations.
Effects of City Expansion on Heat Stress under Climate Change Conditions
Publisher: Public Library of Science (PLoS)
Date: 10-02-2015
Do Convection-Permitting Regional Climate Models Improve Projections of Future Precipitation Change?
Publisher: American Meteorological Society
Date: 2017
Abstract: Regional climate projections are used in a wide range of impact studies, from assessing future flood risk to climate change impacts on food and energy production. These model projections are typically at 12–50-km resolution, providing valuable regional detail but with inherent limitations, in part because of the need to parameterize convection. The first climate change experiments at convection-permitting resolution (kilometer-scale grid spacing) are now available for the United Kingdom the Alps Germany Sydney, Australia and the western United States. These models give a more realistic representation of convection and are better able to simulate hourly precipitation characteristics that are poorly represented in coarser-resolution climate models. Here we examine these new experiments to determine whether future midlatitude precipitation projections are robust from coarse to higher resolutions, with implications also for the tropics. We find that the explicit representation of the convective storms themselves, only possible in convection-permitting models, is necessary for capturing changes in the intensity and duration of summertime rain on daily and shorter time scales. Other aspects of rainfall change, including changes in seasonal mean precipitation and event occurrence, appear robust across resolutions, and therefore coarse-resolution regional climate models are likely to provide reliable future projections, provided that large-scale changes from the global climate model are reliable. The improved representation of convective storms also has implications for projections of wind, hail, fog, and lightning. We identify a number of impact areas, especially flooding, but also transport and wind energy, for which very high-resolution models may be needed for reliable future assessments.
Factors influencing the development of violent pyroconvection. Part I: Fire size and stability
Publisher: CSIRO Publishing
Date: 21-05-2021
DOI: 10.1071/WF20040
Abstract: Violent fire-driven convection can manifest as towering pyrocumulus (pyroCu) or pyrocumulonimbus (pyroCb) clouds, which can have devastating impacts on the environment and society. Their associated fire spread is erratic, unpredictable and not generally suppressible. Research into large pyroconvective events has mainly focused on the atmospheric processes involved in normal atmospheric convection, or on surface fire weather and associated fuel conditions. There has been comparatively less attention paid to the role of the fire itself in these coupled fire–atmosphere events. This paper draws on recent insights into dynamic fire propagation and extreme wildfire development to investigate how the fire influences the occurrence of violent pyroconvective events. A static heat source of variable dimension and intensity is used. This is accompanied by a companion paper that extends the analysis by including the effect of fire geometry on the pyroconvective plume. The analyses indicate that the spatial expanse and intensity of large fires are critical factors driving the development of pyroconvective plumes and can override the influence of the stability of the atmosphere. These findings provide motivation for further investigation into the effect of the fire’s attributes on the immediate atmosphere and have the potential to improve forecasting of blow-up fire events.
Factors influencing the development of violent pyroconvection. Part II: Fire geometry and intensity
Publisher: CSIRO Publishing
Date: 21-05-2021
DOI: 10.1071/WF20041
Abstract: Fire spread associated with violent pyrogenic convection is highly unpredictable and difficult to suppress. Wildfire-driven convection may generate cumulonimbus (storm) clouds, also known as pyrocumulonimbus (pyroCb). Research into such phenomena has tended to treat the fire on the surface and convection in the atmosphere above as separate processes. We used a numerical model to examine the effect of fire geometry on the height of a pyroconvective plume, using idealised model runs in a neutral atmosphere. The role of geometry was investigated because large areal fires have been associated with the development of pyroCb. Complementary results (detailed in Part I) are extended by considering the effect that fire shape can have on plume height by comparing circular, square, and rectangular fires of varying length and width, representing the difference between firelines and areal fires. Results reveal that the perimeter/area ratio influenced the amount of entrainment that the plume experiences and therefore the height to which the plume rises before it loses buoyancy. These results will aid in the prediction of blow-up fires (whereby a fire exhibits a rapid increase in rate of spread or rate of spread) and may therefore be useful in determining where fire agencies deploy their limited resources.
Precipitation over urban areas in the western Maritime Continent using a convection-permitting model
Publisher: Springer Science and Business Media LLC
Date: 02-11-2016
Evaluating CMIP5 Model Agreement for Multiple Drought Metrics
Publisher: American Meteorological Society
Date: 06-2018
Abstract: Global climate models play an important role in quantifying past and projecting future changes in drought. Previous studies have pointed to shortcomings in these models for simulating droughts, but systematic evaluation of their level of agreement has been limited. Here, historical simulations (1950–2004) for 20 models from the latest Coupled Model Intercomparison Project (CMIP5) were analyzed for a variety of drought metrics and thresholds using a standardized drought index. Model agreement was investigated for different types of drought (precipitation, runoff, and soil moisture) and how this varied with drought severity and duration. At the global scale, climate models were shown to agree well on most precipitation drought metrics, but systematically underestimated precipitation drought intensity compared to observations. Conversely, simulated runoff and soil moisture droughts varied significantly across models, particularly for intensity. Differences in precipitation simulations were found to explain model differences in runoff and soil moisture drought metrics over some regions, but predominantly with respect to drought intensity. This suggests it is insufficient to evaluate models for precipitation droughts to increase confidence in model performance for other types of drought. This study shows large but metric-dependent discrepancies in CMIP5 for modeling different types of droughts that relate strongly to the component models (i.e., atmospheric or land surface scheme) used in the coupled modeling systems. Our results point to a need to consider multiple models in drought impact studies to account for high model uncertainties.
Middle East climate simulation and dominant precipitation processes
Publisher: Wiley
Date: 2004
DOI: 10.1002/JOC.1084
Local sea surface temperatures add to extreme precipitation in northeast Australia during la Niña
Publisher: American Geophysical Union (AGU)
Date: 18-05-2012
DOI: 10.1029/2012GL052014
Review of Australian east coast low pressure systems and associated extremes
Publisher: Springer Science and Business Media LLC
Date: 04-06-2019
Investigation into the controversial association of Streptococcus gallolyticus with colorectal cancer and adenoma
Publisher: Springer Science and Business Media LLC
Date: 19-11-2009
Evaluating Precipitation Errors Using the Environmentally Conditioned Intensity‐Frequency Decomposition Method
Publisher: American Geophysical Union (AGU)
Date: 07-2021
DOI: 10.1029/2020MS002447
Abstract: A fundamental issue when evaluating the simulation of precipitation is the difficulty of quantifying specific sources of errors and recognizing compensation of errors. We assess how well a large ensemble of high‐resolution simulations represents the precipitation associated with strong cyclones. We propose a framework to breakdown precipitation errors according to different dynamical (vertical velocity) and thermodynamical (vertically integrated water vapor) regimes and the frequency and intensity of precipitation. This approach approximates the error in the total precipitation of each regime as the sum of three terms describing errors in the large‐scale environmental conditions, the frequency of precipitation and its intensity. We show that simulations produce precipitation too often, that its intensity is too weak, that errors are larger for weak than for strong dynamical forcing and that biases in the vertically integrated water vapor can be large. Using the error breakdown presented above, we define four new error metrics differing on the degree to which they include the compensation of errors. We show that convection‐permitting simulations consistently improve the simulation of precipitation compared to coarser‐resolution simulations using parameterized convection, and that these improvements are revealed by our new approach but not by traditional metrics which can be affected by compensating errors. These results suggest that convection‐permitting models are more likely to produce better results for the right reasons. We conclude that the novel decomposition and error metrics presented in this study give a useful framework that provides physical insights about the sources of errors and a reliable quantification of errors.
Future changes in extreme weather and pyroconvection risk factors for Australian wildfires
Publisher: Springer Science and Business Media LLC
Date: 11-07-2019
DOI: 10.1038/S41598-019-46362-X
Abstract: Extreme wildfires have recently caused disastrous impacts in Australia and other regions of the world, including events with strong convective processes in their plumes (i.e., strong pyroconvection). Dangerous wildfire events such as these could potentially be influenced by anthropogenic climate change, however, there are large knowledge gaps on how these events might change in the future. The McArthur Forest Fire Danger Index (FFDI) is used to represent near-surface weather conditions and the Continuous Haines index (CH) is used here to represent lower to mid-tropospheric vertical atmospheric stability and humidity measures relevant to dangerous wildfires and pyroconvective processes. Projected changes in extreme measures of CH and FFDI are examined using a multi-method approach, including an ensemble of global climate models together with two ensembles of regional climate models. The projections show a clear trend towards more dangerous near-surface fire weather conditions for Australia based on the FFDI, as well as increased pyroconvection risk factors for some regions of southern Australia based on the CH. These results have implications for fields such as disaster risk reduction, climate adaptation, ecology, policy and planning, noting that improved knowledge on how climate change can influence extreme wildfires can help reduce future impacts of these events.
Improving the characteristics of streamflow modeled by regional climate models
Publisher: Elsevier BV
Date: 12-2003
Extreme precipitation in WRF during the Newcastle East Coast Low of 2007
Publisher: Springer Science and Business Media LLC
Date: 28-07-2016
Impact of Land Surface Initialization Approach on Subseasonal Forecast Skill: A Regional Analysis in the Southern Hemisphere
Publisher: American Meteorological Society
Date: 02-2014
Abstract: The authors use a sophisticated coupled land–atmosphere modeling system for a Southern Hemisphere subdomain centered over southeastern Australia to evaluate differences in simulation skill from two different land surface initialization approaches. The first approach uses equilibrated land surface states obtained from offline simulations of the land surface model, and the second uses land surface states obtained from reanalyses. The authors find that land surface initialization using prior offline simulations contribute to relative gains in subseasonal forecast skill. In particular, relative gains in forecast skill for temperature of 10%–20% within the first 30 days of the forecast can be attributed to the land surface initialization method using offline states. For precipitation there is no distinct preference for the land surface initialization method, with limited gains in forecast skill irrespective of the lead time. The authors evaluated the asymmetry between maximum and minimum temperatures and found that maximum temperatures had the largest gains in relative forecast skill, exceeding 20% in some regions. These results were statistically significant at the 98% confidence level at up to 60 days into the forecast period. For minimum temperature, using reanalyses to initialize the land surface contributed to relative gains in forecast skill, reaching 40% in parts of the domain that were statistically significant at the 98% confidence level. The contrasting impact of the land surface initialization method between maximum and minimum temperature was associated with different soil moisture coupling mechanisms. Therefore, land surface initialization from prior offline simulations does improve predictability for temperature, particularly maximum temperature, but with less obvious improvements for precipitation and minimum temperature over southeastern Australia.
Accounting for skill in trend, variability, and autocorrelation facilitates better multi-model projections: Application to the AMOC and temperature time series
Publisher: Public Library of Science (PLoS)
Date: 10-04-2019
Trends and low frequency variability of East Coast Lows in the twentieth century
Publisher: CSIRO Publishing
Date: 31-12-2018
DOI: 10.22499/3.6801.001
Using large-scale diagnostic quantities to investigate change in East Coast Lows
Publisher: Springer Science and Business Media LLC
Date: 23-01-2015
Spatial, Temporal, and Multivariate Bias in Regional Climate Model Simulations
Publisher: American Geophysical Union (AGU)
Date: 10-06-2021
DOI: 10.1029/2020GL092058
Abstract: Correction of atmospheric variables to remove systematic biases in global climate model (GCM) simulations before downscaling offers a means of improving climate simulation accuracy in climate change impact assessments. Various mathematical approaches have been used to correct the lateral and lower boundary conditions of regional climate models (RCMs). Most of these techniques correct only the magnitude of each variable in idually over time without regard to spatial and multivariate bias. Here, we investigate how well an RCM is able to reproduce the dependence of an observed variable based on three aspects: temporal, spatial, and multivariate. Results show that the RCM simulations with univariate bias‐corrected GCM boundary conditions perform well in capturing both temporal and spatial dependence. However, all RCM simulations do not show improvement in the representation of dependence between variables, indicating the need for alternatives that correct systematic biases in multivariate dependence in both lateral and lower boundary conditions.
The influence of inter-annually varying albedo on regional climate and drought
Publisher: Springer Science and Business Media LLC
Date: 05-05-2013
Impacts of model initialization on an integrated surface water - groundwater model
Publisher: Wiley
Date: 04-2015
DOI: 10.1002/HYP.10478
Quantifying the overall added value of dynamical downscaling and the contribution from different spatial scales
Publisher: American Geophysical Union (AGU)
Date: 26-02-2016
DOI: 10.1002/2015JD024009
How do different sensors impact IMERG precipitation estimates during hurricane days?
Publisher: Elsevier BV
Date: 06-2021
Comparison of various climate change projections of eastern Australian rainfall
Publisher: Bureau of Meteorology, Australia
Date: 03-2015
DOI: 10.22499/2.6501.006
Rapid, long-distance dispersal by pumice rafting
Publisher: Public Library of Science (PLoS)
Date: 18-07-2012
Evaluation of downscaled daily rainfall hindcasts over Sydney, Australia using statistical and dynamical downscaling approaches
Publisher: IWA Publishing
Date: 03-07-2014
DOI: 10.2166/NH.2013.094
Abstract: The assessment of local and regional impacts of climate change often requires downscaling of general circulation model (GCM) projections from coarser GCM-scale to finer local- or catchment-scale spatial resolution. This paper provides an assessment of two downscaling approaches for simulation of daily rainfall over Sydney, Australia. The two downscaling alternatives compared include a multivariate multisite statistical downscaling model based on semi-parametric conditional simulation and a dynamical downscaling approach that uses the National Center for Atmospheric Research (NCAR) weather research and forecasting (WRF) model. The two approaches are evaluated for their ability to reproduce important at-site rainfall statistics at a network of 45 raingauge stations and regional statistics over the catchment area of the Warragamba Dam (9,050 km2). The results indicate that the simulations from these approaches capture many regionally observed climate features, including the simulated seasonal and annual means and daily extreme rainfall values. Further analyses suggest that the statistical downscaling approach provides improved simulations of attributes related to point rainfall, spell lengths and amounts, whereas the dynamical approach is well-suited for applications where regionally averaged rainfall is of primary concern.
The Importance of the One‐Dimensional Assumption in Soil Moisture ‐ Rainfall Depth Correlation at Varying Spatial Scales
Publisher: American Geophysical Union (AGU)
Date: 18-03-2019
DOI: 10.1029/2018JD029762
Sensitivity of atypical lateral fire spread to wind and slope
Publisher: American Geophysical Union (AGU)
Date: 22-02-2016
DOI: 10.1002/2015GL067343
Reducing surgical site infections in low-income and middle-income countries (FALCON): a pragmatic, multicentre, stratified, randomised controlled trial
Publisher: Elsevier BV
Date: 11-2021
Water vapor transport and the production of precipitation in the Eastern fertile crescent
Publisher: American Meteorological Society
Date: 12-2006
DOI: 10.1175/JHM550.1
Abstract: The study presented here attempts to quantify the significance of southerly water vapor fluxes on precipitation occurring in the eastern Fertile Crescent region. The water vapor fluxes were investigated at high temporal and spatial resolution by using a Regional Climate Model [fifth-generation Pennsylvania State University–NCAR Mesoscale Model (MM5)–Noah land surface model] to downscale the NCEP–NCAR reanalysis. Using the Iterative Self-Organizing Data Analysis Techniques (ISODATA) clustering algorithm, the 200 largest precipitation events, occurring from 1990 through 1994, were grouped into classes based on the similarity of their water vapor fluxes. Results indicate that, while southerly fluxes were dominant in 24% of tested events, these events produced 43% of the total precipitation produced by the 200 largest events. Thus, while the majority of precipitation events occurring in the Fertile Crescent involve significant water vapor advected from the west, those events that included southerly fluxes produced much larger precipitation totals. This suggests that changes that affect these southerly fluxes more than the westerly fluxes (e.g., changes in the Indian monsoon, movement of the head of the Persian Gulf, etc.) may have a relatively strong affect on the total precipitation falling in the Fertile Crescent even though they affect relatively few precipitation events. To obtain a clearer view of the precipitation mechanisms, the authors used a linear model, along with the estimated water vapor fluxes, to downscale from 25 to 1 km. The result shows a spectrum of mountain scales not seen in the regional model, exerting tight control on the precipitation pattern.
Global vegetation biomass change (1988-2008) and attribution to environmental and human drivers
Publisher: Wiley
Date: 21-12-2013
DOI: 10.1111/GEB.12024
Identification of a novel pneumococcal vaccine antigen preferentially expressed during meningitis in mice
Publisher: American Society for Clinical Investigation
Date: 06-2012
DOI: 10.1172/JCI45850
The Addition of Temperature to the TSS-RESTREND Methodology Significantly Improves the Detection of Dryland Degradation
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 07-2019
Natural hazards in Australia: droughts
Publisher: Springer Science and Business Media LLC
Date: 19-09-2016
Intensification of subhourly heavy rainfall
Publisher: American Association for the Advancement of Science (AAAS)
Date: 11-11-2022
Abstract: Short-duration rainfall extremes can cause flash flooding with associated impacts. Previous studies of climate impacts on extreme precipitation have focused mainly on daily rain totals. Subdaily extremes are often generated in small areas that can be missed by gauge networks or satellites and are not resolved by climate models. Here, we show a robust positive trend of at least 20% per decade in subhourly extreme rainfall near Sydney, Australia, over 20 years, despite no evidence of trends at hourly or daily scales. This trend is seen consistently in storms tracked using multiple independent ground radars, is consistent with rain-gauge data, and does not appear to be associated with known natural variations. This finding suggests that subhourly rainfall extremes may be increasing substantially faster than those on more widely reported time scales.
Pneumococcal histidine triad proteins are regulated by the Zn2+-dependent repressor AdcR and inhibit complement deposition through the recruitment of complement factor H.
Publisher: Wiley
Date: 29-10-2009
DOI: 10.1096/FJ.08-119537
Abstract: The pneumococcal histidine triad (Pht) proteins are a recently recognized family of surface proteins, comprising 4 members: PhtA, PhtB, PhtD, and PhtE. They are being promoted for inclusion in a multicomponent pneumococcal protein vaccine currently under development, but to date, their biological functions and their relative contributions to pathogenesis have not been clarified. In this study, the involvement of these proteins in pneumococcal virulence was investigated in murine models of sepsis and pneumonia by using defined, nonpolar mutants of the respective genes in Streptococcus pneumoniae D39. In either challenge model, mutagenesis of all 4 genes was required to completely abolish virulence relative to the wild-type, suggesting significant functional redundancy among Pht proteins. The in vivo expression of pht genes was significantly up-regulated in the nasopharynx and lungs compared with blood. We provide unequivocal molecular evidence for Zn(2+)-dependent, AdcR-mediated, regulation of pht gene expression by real-time reverse transcriptase-polymerase chain reaction, Western blotting, and electrophoretic mobility-shift assays. We also present the first direct evidence for the biological function of this protein family by demonstrating that Pht proteins are required for inhibition of complement deposition on the pneumococcal surface through the recruitment of complement factor H.
21st century climate change in the Middle East
Publisher: Springer Science and Business Media LLC
Date: 29-07-2009
Evaluating global reanalysis datasets for provision of boundary conditions in regional climate modelling
Publisher: Springer Science and Business Media LLC
Date: 23-01-2016
Evaluating the performance of a WRF physics ensemble over South-East Australia
Publisher: Springer Science and Business Media LLC
Date: 19-11-2011
Multi-site evaluation of terrestrial evaporation models using FLUXNET data
Publisher: Elsevier BV
Date: 04-2014
Simulation of Flash-Flood-Producing Storm Events in Saudi Arabia Using the Weather Research and Forecasting Model*
Publisher: American Meteorological Society
Date: 04-2015
Abstract: The challenges of monitoring and forecasting flash-flood-producing storm events in data-sparse and arid regions are explored using the Weather Research and Forecasting (WRF) Model (version 3.5) in conjunction with a range of available satellite, in situ, and reanalysis data. Here, we focus on characterizing the initial synoptic features and examining the impact of model parameterization and resolution on the reproduction of a number of flood-producing rainfall events that occurred over the western Saudi Arabian city of Jeddah. Analysis from the European Centre for Medium-Range Weather Forecasts (ECMWF) interim reanalysis (ERA-Interim) data suggests that mesoscale convective systems associated with strong moisture convergence ahead of a trough were the major initial features for the occurrence of these intense rain events. The WRF Model was able to simulate the heavy rainfall, with driving convective processes well characterized by a high-resolution cloud-resolving model. The use of higher (1 km vs 5 km) resolution along the Jeddah coastline favors the simulation of local convective systems and adds value to the simulation of heavy rainfall, especially for deep-convection-related extreme values. At the 5-km resolution, corresponding to an intermediate study domain, simulation without a cumulus scheme led to the formation of deeper convective systems and enhanced rainfall around Jeddah, illustrating the need for careful model scheme selection in this transition resolution. In analysis of multiple nested WRF simulations (25, 5, and 1 km), localized volume and intensity of heavy rainfall together with the duration of rainstorms within the Jeddah catchment area were captured reasonably well, although there was evidence of some displacements of rainstorm events.
Evaluation of the regional climate response in Australia to large-scale climate modes in the historical NARCliM simulations
Publisher: Springer Science and Business Media LLC
Date: 22-12-2017
Evaluation of the CABLEv2.3.4 Land Surface Model Coupled to NU‐WRFv3.9.1.1 in Simulating Temperature and Precipitation Means and Extremes Over CORDEX AustralAsia Within a WRF Physics Ensemble
Publisher: American Geophysical Union (AGU)
Date: 12-2019
DOI: 10.1029/2019MS001845
Selecting CMIP6 GCMs for CORDEX Dynamical Downscaling: Model Performance, Independence, and Climate Change Signals
Publisher: American Geophysical Union (AGU)
Date: 04-2022
DOI: 10.1029/2021EF002625
Abstract: Global climate models (GCMs) are essential for investigating climate change, but their coarse scale limits their efficacy for climate adaptation planning at the regional scales where climate impacts manifest. Dynamical downscaling of GCM outputs better resolves regional climate and thus provides improved guidance for climate policy at regional scales. Being expensive to run, downscaling uses a subset of GCMs, necessitating careful GCM selection. This evaluation identifies a suitable subset of CMIP6 GCMs for downscaling over Australia by assessing in idual GCMs against three criteria: (a) performance simulating daily climate variable distributions, climate means, extremes, and modes (b) model independence and (c) climate change signal ersity. Over Australia, GCMs are generally biased cold (warm) for maximum (minimum) temperature, with larger biases for minimum temperature. GCMs are generally wet biased, especially over the monsoonal north, but dry biased over eastern regions. Most GCMs show larger biases for temperature and precipitation over geographically complex, heavily populated eastern regions, relative to other regions. Evaluations identify a distinct group of 11 GCMs that perform consistently poorly across climate variables, statistics, and timescales with widespread, statistically significant biases, versus 13 GCMs that show consistent adequate‐to‐good performance with substantially reduced errors. Assessment of model independence highlights the lack of independence between several high‐performing GCMs, particularly from allied modeling groups, demonstrating the importance of careful ensemble selection when making selective s les of climate space. Once GCM climate signal ersity is considered, 6–8 mid‐to‐high‐performing, independent GCMs occupy the full range of the future climate space and, thus, are suitable for dynamical downscaling over CORDEX‐Australasia.
Natural hazards in Australia: storms, wind and hail
Publisher: Springer Science and Business Media LLC
Date: 22-07-2016
Global long-term passive microwave satellite-based retrievals of vegetation optical depth
Publisher: American Geophysical Union (AGU)
Date: 22-09-2011
DOI: 10.1029/2011GL048684
Optimally choosing small ensemble members to produce robust climate simulations
Publisher: IOP Publishing
Date: 12-2013
Bias-corrected regional climate projections of extreme rainfall in south-east Australia
Publisher: Springer Science and Business Media LLC
Date: 28-09-2017
Estimation of future changes in photovoltaic potential in Australia due to climate change
Publisher: Wiley
Date: 27-05-2021
Hydroclimatic variability and predictability: a survey of recent research
Publisher: Copernicus GmbH
Date: 25-07-2017
DOI: 10.5194/HESS-21-3777-2017
Abstract: Abstract. Recent research in large-scale hydroclimatic variability is surveyed, focusing on five topics: (i) variability in general, (ii) droughts, (iii) floods, (iv) land–atmosphere coupling, and (v) hydroclimatic prediction. Each surveyed topic is supplemented by illustrative ex les of recent research, as presented at a 2016 symposium honoring the career of Professor Eric Wood. Taken together, the recent literature and the illustrative ex les clearly show that current research into hydroclimatic variability is strong, vibrant, and multifaceted.
How well do general circulation models represent low-frequency rainfall variability?
Publisher: American Geophysical Union (AGU)
Date: 03-2014
DOI: 10.1002/2012WR013085
Developing an improved soil moisture dataset by blending passive and active microwave satellite-based retrievals
Publisher: Copernicus GmbH
Date: 02-2011
Abstract: Abstract. Combining information derived from satellite-based passive and active microwave sensors has the potential to offer improved estimates of surface soil moisture at global scale. We develop and evaluate a methodology that takes advantage of the retrieval characteristics of passive (AMSR-E) and active (ASCAT) microwave satellite estimates to produce an improved soil moisture product. First, volumetric soil water content (m3 m−3) from AMSR-E and degree of saturation (%) from ASCAT are rescaled against a reference land surface model data set using a cumulative distribution function matching approach. While this imposes any bias of the reference on the rescaled satellite products, it adjusts them to the same range and preserves the dynamics of original satellite-based products. Comparison with in situ measurements demonstrates that where the correlation coefficient between rescaled AMSR-E and ASCAT is greater than 0.65 ("transitional regions"), merging the different satellite products increases the number of observations while minimally changing the accuracy of soil moisture retrievals. These transitional regions also delineate the boundary between sparsely and moderately vegetated regions where rescaled AMSR-E and ASCAT, respectively, are used for the merged product. Therefore the merged product carries the advantages of better spatial coverage overall and increased number of observations, particularly for the transitional regions. The combination method developed has the potential to be applied to existing microwave satellites as well as to new missions. Accordingly, a long-term global soil moisture dataset can be developed and extended, enhancing basic understanding of the role of soil moisture in the water, energy and carbon cycles.
Evaluation of long-term precipitation and temperature WRF simulations for southeast Australia
Publisher: Inter-Research Science Center
Date: 24-02-2016
DOI: 10.3354/CR01366
Potential impacts of a future persistent El Nino or La Nina on three subspecies of Australian butterflies
Publisher: Wiley
Date: 22-07-2017
DOI: 10.1111/BTP.12356
Trend-preserving blending of passive and active microwave soil moisture retrievals
Publisher: Elsevier BV
Date: 08-2012
Natural hazards in Australia: heatwaves
Publisher: Springer Science and Business Media LLC
Date: 11-04-2016
Impact of bias-corrected reanalysis-derived lateral boundary conditions on WRF simulations
Publisher: American Geophysical Union (AGU)
Date: 08-2017
DOI: 10.1002/2017MS001003
Constraining snowmelt in a temperature-index model using simulated snow densities
Publisher: Elsevier BV
Date: 09-2014
Natural hazards in Australia: extreme bushfire
Publisher: Springer Science and Business Media LLC
Date: 06-10-2016
Independently assessing the representation of midlatitude cyclones in high‐resolution reanalyses using satellite observed winds
Publisher: Wiley
Date: 18-08-2018
DOI: 10.1002/JOC.5245
A space and time scale-dependent nonlinear geostatistical approach for downscaling daily precipitation and temperature
Publisher: American Geophysical Union (AGU)
Date: 08-2015
DOI: 10.1002/2014WR016729
A comparison of methods to estimate future sub-daily design rainfall
Publisher: Elsevier BV
Date: 12-2017
To what degree does land-atmosphere feedback exacerbate drought in South East Australia?
Publisher: Copernicus GmbH
Date: 23-03-2020
DOI: 10.5194/EGUSPHERE-EGU2020-4313
Abstract: & & South East Australia is characterised by a erse climate ranging from lush, temperate mountain ranges to hot and arid grasslands. The region is home to Australia's largest river system, the Murray-Darling. The Murray-Darling Basin is an important agricultural region, generating almost 50% of Australia's total irrigated agricultural production in 2018. Rainfall in this region is typically highly variable and subject to severe drought. The Millennium Drought (2001-2009), widely known as the worst drought on record and one of the most severe in the world, has now been superseded by a worse drought (2017-present), setting a new extreme in the drought record. During the current drought, rainfall, root zone soil moisture and water storages have reached record-breaking low levels. High temperatures have also broken historical records on multiple occasions since the drought began. Drought conditions and exceptionally high temperatures have dried the landscape, which has led to intense bushfires that have so far ravaged over 5 million hectares.& & & & Yet the degree to which the land surface exacerbates drought in the Murray-Darling Basin remains unknown. In other words, the relative importance of local versus remote processes affecting rainfall, particularly during drought, is uncertain. Where does the moisture come from, and how strongly do local land surface processes attenuate or lify this atmospheric moisture to affect local rainfall? Establishing the evaporative source regions that supply moisture for rainfall can help reveal the mechanisms driving anomalously low rainfall. In the case of drought, it can help reveal whether anomalous rainfall was due to a reduction in source evaporation, anomalous atmospheric circulation (i.e., the moisture was generated but transported somewhere else), land surface control on the atmosphere through feedbacks, or a combination of factors.& & & & We used a Lagrangian back-trajectory approach to determine the long-term average evaporative source regions that supply Australia's rainfall, and the level of recycling that rainfall undergoes. The back-trajectory model tracked water vapour from the location of rainfall events backward in time and space and identified the evaporative origin. From this, we calculated the proportion of rainfall falling across the Murray-Darling Basin that originated as evapotranspiration from the Basin itself that is, the rainfall recycling ratio.& & & & By combining this long-term baseline of source region and rainfall recycling with anomalies of source region evaporation and local atmospheric boundary layer properties, we found that the drivers of low rainfall changed through time during the Millennium Drought. At the peak of the Drought the anomalously low rainfall was driven by a lack of atmospheric moisture advected from the identified typical source region at other times the low rainfall was due to local conditions unfavorable for the precipitation of available moisture. Overall we found that land surface control on the atmosphere exacerbated the Millennium Drought by approximately 10%.& &
The impact of an urban canopy and anthropogenic heat fluxes on Sydney's climate
Publisher: Wiley
Date: 02-02-2017
DOI: 10.1002/JOC.5001
The CORDEX-Australasia ensemble: evaluation and future projections
Publisher: Springer Science and Business Media LLC
Date: 24-09-2020
Regional climate simulation over Australia's Murray-Darling basin: A multitemporal assessment
Publisher: American Geophysical Union (AGU)
Date: 28-07-2010
DOI: 10.1029/2010JD013816
Fire weather simulation skill by the Weather Research and Forecasting (WRF) model over south-east Australia from 1985 to 2009
Publisher: CSIRO Publishing
Date: 2013
DOI: 10.1071/WF12048
Abstract: The fire weather of south-east Australia from 1985 to 2009 has been simulated using the Weather Research and Forecasting (WRF) model. The US National Oceanic and Atmospheric Administration Centers for Environmental Prediction and National Center for Atmospheric Research reanalysis supplied the lateral boundary conditions and initial conditions. The model simulated climate and the reanalysis were evaluated against station-based observations of the McArthur Forest Fire Danger Index (FFDI) using probability density function skill scores, annual cumulative FFDI and days per year with FFDI above 50. WRF simulated the main features of the FFDI distribution and its spatial variation, with an overall positive bias. Errors in average FFDI were caused mostly by errors in the ability of WRF to simulate relative humidity. In contrast, errors in extreme FFDI values were driven mainly by WRF errors in wind speed simulation. However, in both cases the quality of the observed data is difficult to ascertain. WRF run with 50-km grid spacing did not consistently improve upon the reanalysis statistics. Decreasing the grid spacing to 10km led to fire weather that was generally closer to observations than the reanalysis across the full range of evaluation metrics used here. This suggests it is a very useful tool for modelling fire weather over the entire landscape of south-east Australia.
Air quality impacts on rooftop photovoltaic energy production during the 2019–2020 Australian bushfires season
Publisher: Elsevier BV
Date: 06-2023
Erratum to: An investigation of future fuel load and fire weather in Australia
Publisher: Springer Science and Business Media LLC
Date: 03-10-2016
A Bayesian posterior predictive framework for weighting ensemble regional climate models
Publisher: Copernicus GmbH
Date: 23-06-2017
Abstract: Abstract. We present a novel Bayesian statistical approach to computing model weights in climate change projection ensembles in order to create probabilistic projections. The weight of each climate model is obtained by weighting the current day observed data under the posterior distribution admitted under competing climate models. We use a linear model to describe the model output and observations. The approach accounts for uncertainty in model bias, trend and internal variability, including error in the observations used. Our framework is general, requires very little problem-specific input, and works well with default priors. We carry out cross-validation checks that confirm that the method produces the correct coverage.
Supplementary material to "On the non-stationarity of hydrological response in anthropogenically unaffected catchments: An Australian perspective"
Publisher: Copernicus GmbH
Date: 29-07-2016
Central role of manganese in regulation of stress responses, physiology, and metabolism in Streptococcus pneumoniae
Publisher: American Society for Microbiology
Date: 09-2010
DOI: 10.1128/JB.00064-10
Abstract: The importance of Mn 2+ for pneumococcal physiology and virulence has been studied extensively. However, the specific cellular role(s) for which Mn 2+ is required are yet to be fully elucidated. Here, we analyzed the effect of Mn 2+ limitation on the transcriptome and proteome of Streptococcus pneumoniae D39. This was carried out by comparing a deletion mutant lacking the solute binding protein of the high-affinity Mn 2+ transporter, pneumococcal surface antigen A (PsaA), with its isogenic wild-type counterpart. We provide clear evidence for the Mn 2+ -dependent regulation of the expression of oxidative-stress-response enzymes SpxB and Mn 2+ -SodA and virulence-associated genes pcpA and prtA . We also demonstrate the upregulation of at least one oxidative- and nitrosative-stress-response gene cluster, comprising adhC , nmlR , and czcD , in response to Mn 2+ stress. A significant increase in 6-phosphogluconate dehydrogenase activity in the psaA mutant grown under Mn 2+ -replete conditions and upregulation of an oligopeptide ABC permease (AppDCBA) were also observed. Together, the results of transcriptomic and proteomic analyses provided evidence for Mn 2+ having a central role in activating or stimulating enzymes involved in central carbon and general metabolism. Our results also highlight the importance of high-affinity Mn 2+ transport by PsaA in pneumococcal competence, physiology, and metabolism and elucidate mechanisms underlying the response to Mn 2+ stress.
Precipitation bias correction of very high resolution regional climate models
Publisher: Copernicus GmbH
Date: 06-11-2013
DOI: 10.5194/HESS-17-4379-2013
Abstract: Abstract. Regional climate models are prone to biases in precipitation that are problematic for use in impact models such as hydrology models. A large number of methods have already been proposed aimed at correcting various moments of the rainfall distribution. They all require that the model produce the same or a higher number of rain days than the observational data sets, which are usually gridded data sets. Models have traditionally met this condition because their spatial resolution was coarser than the observational grids. But recent climate simulations use higher resolution and the models are likely to systematically produce fewer rain days than the gridded observations. In this study, model outputs from a simulation at 2 km resolution are compared with gridded and in situ observational data sets to determine whether the new scenario calls for revised methodologies. The gridded observations are found to be inadequate to correct the high-resolution model at daily timescales, because they are subjected to too frequent low intensity precipitation due to spatial averaging. A histogram equalisation bias correction method was adapted to the use of station, alleviating the problems associated with relative low-resolution observational grids. The wet-day frequency condition might not be satisfied for extremely dry biases, but the proposed approach substantially increases the applicability of bias correction to high-resolution models. The method is efficient at bias correcting both seasonal and daily characteristic of precipitation, providing more accurate information that is crucial for impact assessment studies.
Validation of Australian atmospheric aerosols from reanalysis data and CMIP6 simulations
Publisher: Elsevier BV
Date: 12-2021
Introducing First-Year Undergraduate Students the Fundamentals of Antibiotic Sensitivity Testing through a Combined Computer Simulation and Face-to-Face Laboratory Session
Publisher: American Society for Microbiology
Date: 31-08-2022
Abstract: Determining the antibiotic sensitivity of disease-causing microorganisms is a fundamental process in a clinical microbiology laboratory. With the continued use of antibiotics, the emergence of antibiotic resistance has become a significant health issue.
An investigation of future fuel load and fire weather in Australia
Publisher: Springer Science and Business Media LLC
Date: 14-09-2016
Demonstration of a geostatistical approach to physically consistent downscaling of climate modeling simulations
Publisher: American Geophysical Union (AGU)
Date: 2013
DOI: 10.1029/2012WR012602
On the non-stationarity of hydrological response in anthropogenically unaffected catchments: an Australian perspective
Publisher: Copernicus GmbH
Date: 12-01-2017
Abstract: Abstract. Increases in greenhouse gas concentrations are expected to impact the terrestrial hydrologic cycle through changes in radiative forcings and plant physiological and structural responses. Here, we investigate the nature and frequency of non-stationary hydrological response as evidenced through water balance studies over 166 anthropogenically unaffected catchments in Australia. Non-stationarity of hydrologic response is investigated through analysis of long-term trend in annual runoff ratio (1984–2005). Results indicate that a significant trend (p 0.01) in runoff ratio is evident in 20 catchments located in three main ecoregions of the continent. Runoff ratio decreased across the catchments with non-stationary hydrologic response with the exception of one catchment in northern Australia. Annual runoff ratio sensitivity to annual fractional vegetation cover was similar to or greater than sensitivity to annual precipitation in most of the catchments with non-stationary hydrologic response indicating vegetation impacts on streamflow. We use precipitation–productivity relationships as the first-order control for ecohydrologic catchment classification. A total of 12 out of 20 catchments present a positive precipitation–productivity relationship possibly enhanced by CO2 fertilization effect. In the remaining catchments, biogeochemical and edaphic factors may be impacting productivity. Results suggest vegetation dynamics should be considered in exploring causes of non-stationary hydrologic response.
Global exposure of population and land‐use to meteorological droughts under different warming levels and SSPs : A CORDEX ‐based study
Publisher: Wiley
Date: 04-08-2021
DOI: 10.1002/JOC.7302
Abstract: Global warming is likely to cause a progressive drought increase in some regions, but how population and natural resources will be affected is still underexplored. This study focuses on global population, forests, croplands and pastures exposure to meteorological drought hazard in the 21st century, expressed as frequency and severity of drought events. As input, we use a large ensemble of climate simulations from the Coordinated Regional Climate Downscaling Experiment (CORDEX), population projections from the NASA‐SEDAC dataset and land‐use projections from the Land‐Use Harmonization 2 project for 1981–2100. The exposure to drought hazard is presented for five Shared Socioeconomic Pathways (SSP1‐SSP5) at four Global Warming Levels (GWLs: 1.5°C to 4°C). Results show that considering only Standardized Precipitation Index (SPI based on precipitation), the SSP3 at GWL4 projects the largest fraction of the global population (14%) to experience an increase in drought frequency and severity (versus 1981–2010), with this value increasing to 60% if temperature is considered (indirectly included in the Standardized Precipitation‐Evapotranspiration Index, SPEI). With SPEI, considering the highest GWL for each SSP, 8 (for SSP2, SSP4, SSP5) and 11 (SSP3) billion people, that is, more than 90%, will be affected by at least one unprecedented drought. For SSP5 at GWL4, approximately 2 × 10 6 km 2 of forests and croplands (respectively, 6% and 11%) and 1.5 × 10 6 km 2 of pastures (19%) will be exposed to increased drought frequency and severity according to SPI, but for SPEI this extent will rise to 17 × 10 6 km 2 of forests (49%), 6 × 10 6 km 2 of pastures (78%) and 12 × 10 6 km 2 of croplands (67%), being mid‐latitudes the most affected. The projected likely increase of drought frequency and severity significantly increases population and land‐use exposure to drought, even at low GWLs, thus extensive mitigation and adaptation efforts are needed to avoid the most severe impacts of climate change.
Reconstructing hydro-climatological data using dynamical downscaling of reanalysis products in data-sparse regions – Application to the Limpopo catchment in southern Africa
Publisher: Elsevier BV
Date: 08-2017
Evaluating Precipitation Datasets Using Surface Water and Energy Budget Closure
Publisher: American Meteorological Society
Date: 05-2020
Abstract: Evaluation of global gridded precipitation datasets typically entails using the in situ or satellite-based data used to derive them, so that out-of-s le testing is usually not possible. Here we detail a methodology that incorporates the physical balance constraints of the surface water and energy budgets to evaluate gridded precipitation estimates, providing the capacity for out-of-s le testing. Performance conclusions are determined by the ability of precipitation products to achieve closure of the linked budgets using adjustments that are within their prescribed uncertainty bounds. We evaluate and compare five global gridded precipitation datasets: IMERG, GPCP, GPCC, REGEN, and MERRA-2. At the spatial level, we show that precipitation is best estimated by GPCC over the high latitudes, by GPCP over the tropics, and by REGEN over North Africa and the Middle East. IMERG and REGEN appear best over Australia and South Asia. Furthermore, our results give insight into the adequacy of prescribed uncertainties of these products and shows that MERRA-2, while being less competent than the other four products in estimating precipitation, has the best representation of uncertainties in its precipitation estimates. The spatial extent of our results is not only limited to grid cells with in situ observations. Therefore, the approach enables a robust evaluation of precipitation estimates and goes some way to addressing the challenge of validation over observation scarce regions.
Large eddy simulation of atypical wildland fire spread on leeward slopes
Publisher: CSIRO Publishing
Date: 2013
DOI: 10.1071/WF12072
Abstract: The WRF-Fire coupled atmosphere–fire modelling system was used to investigate atypical wildland fire spread on steep leeward slopes through a series of idealised numerical simulations. The simulations are used to investigate both the leeward flow characteristics, such as flow separation, and the fire spread from an ignition region at the base of the leeward slope. The fire spread was considered under varying fuel type and with atmosphere-fire coupling both enabled and disabled. When atmosphere–fire coupling is enabled and there is a high fuel mass density, the fire spread closely resembles that expected during fire channelling. Specifically, the fire spread is initially dominated by upslope spread to the mountain ridge line at an average rate of 2.0kmh–1, followed by predominantly lateral spread close to the ridge line at a maximum rate of 3.6kmh–1. The intermittent rapid lateral spread occurs when updraft–downdraft interfaces, which are associated with strongly circulating horizontal winds at the mid-flame height, move across the fire perimeter close to the ridge line. The updraft–downdraft interfaces are formed due to an interaction between the strong pyro-convection and the terrain-modified winds. Through these results, a new physical explanation of fire channelling is proposed.
Analysis of extreme wind gusts using a high-resolution Australian Regional Reanalysis
Publisher: Elsevier BV
Date: 03-2023
Are storm characteristics the same when viewed using merged surface radars or a merged satellite product?
Publisher: American Meteorological Society
Date: 2020
Abstract: High-resolution datasets offer the potential to improve our understanding of spatial and temporal precipitation patterns and storm structures. The goal of this study is to evaluate the similarities and differences of object-based storm characteristics as observed using space- or land-based sensors. The Method of Object-based Diagnostic Evaluation (MODE) Time Domain (MTD) is used to identify and track storm objects in two high-resolution merged datasets: the Integrated Multisatellite Retrievals for Global Precipitation Measurement (IMERG) final product V06B and gauge-corrected ground-radar-based Multi-Radar Multi-Sensor (MRMS) quantitative precipitation estimations. Characteristics associated with landfalling hurricanes were also examined as a separate category of storm. The results reveal that IMERG and MRMS agree reasonably well across many object-based storm characteristics. However, there are some discrepancies that are statistically significant. MRMS storms are more concentrated, with smaller areas and higher peak intensities, which implies higher flash flood risks associated with the storms. On the other hand, IMERG storms can travel longer distances with a higher volume of precipitation, which implies higher risk of riverine flooding. Agreement between the datasets is higher for faster-moving hurricanes in terms of the averaged intensity. Finally, MRMS indicates a higher average precipitation intensity during the hurricane’s lifetime. However, in non-hurricanes, the opposite result was observed. This is likely related to MRMS having higher resolution monitoring the hurricanes from many viewing angles, leading to different signal saturation properties compared to IMERG and/or the dominance of droplet aggregation effects over evaporation effects at lower altitudes.
Zonal winds and southeast Australian rainfall in global and regional climate models
Publisher: Springer Science and Business Media LLC
Date: 28-03-2016
Evaluating reanalysis-driven CORDEX regional climate models over Australia: model performance and errors
Publisher: Springer Science and Business Media LLC
Date: 26-02-2019
The CORDEX-CORE EXP-I Initiative: Description and Highlight Results from the Initial Analysis
Publisher: American Meteorological Society
Date: 02-2022
Abstract: We describe the first effort within the Coordinated Regional Climate Downscaling Experiment–Coordinated Output for Regional Evaluation, or CORDEX-CORE EXP-I. It consists of a set of twenty-first-century projections with two regional climate models (RCMs) downscaling three global climate model (GCM) simulations from the CMIP5 program, for two greenhouse gas concentration pathways (RCP8.5 and RCP2.6), over nine CORDEX domains at ∼25-km grid spacing. Illustrative ex les from the initial analysis of this ensemble are presented, covering a wide range of topics, such as added value of RCM nesting, extreme indices, tropical and extratropical storms, monsoons, ENSO, severe storm environments, emergence of change signals, and energy production. They show that the CORDEX-CORE EXP-I ensemble can provide downscaled information of unprecedented comprehensiveness to increase understanding of processes relevant for regional climate change and impacts, and to assess the added value of RCMs. The CORDEX-CORE EXP-I dataset, which will be incrementally augmented with new simulations, is intended to be a public resource available to the scientific and end-user communities for application to process studies, impacts on different socioeconomic sectors, and climate service activities. The future of the CORDEX-CORE initiative is also discussed.
Implementation of a soil albedo scheme in the CABLEv1.4b land surface model and evaluation against MODIS estimates over Australia
Publisher: Copernicus GmbH
Date: 13-03-2014
Abstract: Abstract. Land surface albedo, the fraction of incoming solar radiation reflected by the land surface, is a key component of the earth system. This study evaluates snow-free surface albedo simulations by the Community Atmosphere Biosphere Land Exchange (CABLEv1.4b) model with the Moderate Resolution Imaging Spectroradiometer (MODIS) albedo. We compare results from two offline simulations over the Australian continent, one with prescribed background snow-free and vegetation-free soil albedo derived from MODIS (the control), and the other with a simple parameterisation based on soil moisture and colour. The control simulation shows that CABLE simulates albedo over Australia reasonably well, with differences with MODIS within an acceptable range. Inclusion of the parameterisation for soil albedo however introduced large errors for the near infra red albedo, especially for desert regions of central Australia. These large errors were not fully explained by errors in soil moisture or parameter uncertainties, but are similar to errors in albedo in other land surface models which use the same soil albedo scheme. Although this new parameterisation has introduced larger errors as compared to prescribing soil albedo, dynamic soil moisture-albedo feedbacks are now enabled in CABLE. Future directions for albedo parameterisations development in CABLE are discussed.
A simple method for Bayesian model averaging of regional climate model projections: Application to southeast Australian temperatures
Publisher: American Geophysical Union (AGU)
Date: 16-07-2016
DOI: 10.1002/2016GL069704
Projected changes in east Australian midlatitude cyclones during the 21st century
Publisher: American Geophysical Union (AGU)
Date: 06-01-2016
DOI: 10.1002/2015GL067267
Temperature response to future urbanization and climate change
Publisher: Springer Science and Business Media LLC
Date: 05-05-2014
Climate change impacts on phenology and yield of hazelnut in Australia
Publisher: Elsevier BV
Date: 2021
The INTENSE project: using observations and models to understand the past, present and future of sub-daily rainfall extremes
Publisher: Copernicus GmbH
Date: 19-06-2018
Abstract: Abstract. Historical in situ sub-daily rainfall observations are essential for the understanding of short-duration rainfall extremes but records are typically not readily accessible and data are often subject to errors and inhomogeneities. Furthermore, these events are poorly quantified in projections of future climate change making adaptation to the risk of flash flooding problematic. Consequently, knowledge of the processes contributing to intense, short-duration rainfall is less complete compared with those on daily timescales. The INTENSE project is addressing this global challenge by undertaking a data collection initiative that is coupled with advances in high-resolution climate modelling to better understand key processes and likely future change. The project has so far acquired data from over 23 000 rain gauges for its global sub-daily rainfall dataset (GSDR) and has provided evidence of an intensification of hourly extremes over the US. Studies of these observations, combined with model simulations, will continue to advance our understanding of the role of local-scale thermodynamics and large-scale atmospheric circulation in the generation of these events and how these might change in the future.
Biases in Estimating Long‐Term Recurrence Intervals of Extreme Events Due To Regionalized Sampling
Publisher: American Geophysical Union (AGU)
Date: 07-08-2023
DOI: 10.1029/2023GL105286
Abstract: Preparing for environmental risks requires estimating the frequencies of extreme events, often from data records that are too short to confirm them directly. This requires fitting a statistical distribution to the data. To improve precision, investigators often pool data from neighboring sites into single s les, referred to as “superstations,” before fitting. We demonstrate that this technique can introduce unexpected biases in typical situations, using wind and rainfall extremes as case studies. When the combined locations have even small differences in the underlying statistics, the regionalization approach gives a fit that may tend toward the highest levels suggested by any of the in idual sites. This bias may be large or small compared to the s ling error, for realistic record lengths, depending on the distribution of the quantity analyzed. The results of this analysis indicate that previous analyses could potentially have overestimated the likelihood of extreme events arising from natural weather variability.
Towards advancing scientific knowledge of climate change impacts on short-duration rainfall extremes
Publisher: The Royal Society
Date: 03-2021
Abstract: A large number of recent studies have aimed at understanding short-duration rainfall extremes, due to their impacts on flash floods, landslides and debris flows and potential for these to worsen with global warming. This has been led in a concerted international effort by the INTENSE Crosscutting Project of the GEWEX (Global Energy and Water Exchanges) Hydroclimatology Panel. Here, we summarize the main findings so far and suggest future directions for research, including: the benefits of convection-permitting climate modelling towards understanding mechanisms of change the usefulness of temperature-scaling relations towards detecting and attributing extreme rainfall change and the need for international coordination and collaboration. Evidence suggests that the intensity of long-duration (1 day+) heavy precipitation increases with climate warming close to the Clausius–Clapeyron (CC) rate (6–7% K −1 ), although large-scale circulation changes affect this response regionally. However, rare events can scale at higher rates, and localized heavy short-duration (hourly and sub-hourly) intensities can respond more strongly (e.g. 2 × CC instead of CC). Day-to-day scaling of short-duration intensities supports a higher scaling, with mechanisms proposed for this related to local-scale dynamics of convective storms, but its relevance to climate change is not clear. Uncertainty in changes to precipitation extremes remains and is influenced by many factors, including large-scale circulation, convective storm dynamics andstratification. Despite this, recent research has increased confidence in both the detectability and understanding of changes in various aspects of intense short-duration rainfall. To make further progress, the international coordination of datasets, model experiments and evaluations will be required, with consistent and standardized comparison methods and metrics, and recommendations are made for these frameworks. This article is part of a discussion meeting issue ‘Intensification of short-duration rainfall extremes and implications for flash flood risks’.
Australian snowpack in the NARCliM ensemble: evaluation, bias correction and future projections
Publisher: Springer Science and Business Media LLC
Date: 19-10-2017
Coupled atmospheric and land surface dynamics over southeast Australia: a review, analysis and identification of future research priorities
Publisher: Wiley
Date: 20-07-2010
DOI: 10.1002/JOC.2206
Performance evaluation of 20CRv3 downscaling using WRF over southern Alaska with focus on temperature and precipitation in glaciated areas
Publisher: Copernicus GmbH
Date: 15-05-2023
DOI: 10.5194/EGUSPHERE-EGU23-10585
Abstract: Global warming has raised mean surface temperatures by 0.99 & #177 0.15 & #176 C from 1850-1900 to 2011-2020. The temperature rise has been greatest in the high latitudes. Alaska has one of the largest temperate and subarctic glaciated areas in the world, which is highly sensitive to climate change. Currently, the mass loss from these glaciers contributes to about a third of the global sea-level rise. For ex le, the tidewater glacier Columbia Glacier located within Prince William Sound is the largest single contributor to sea level rise through its rapid retreat, which started in the early 1980s. Although internal controls strongly influence the tidewater glacier cycle, the ubiquitous retreat of Alaskan tidewater glaciers indicates climatic forcing is involved. However, it is unlikely climate controls the rate of retreat. There are insufficient meteorological observations from this region to assess the role of climate across a whole tidewater cycle. This project reconstructs the regional climate of southern Alaska from 1836& #8211 using dynamical downscaling of the NOAA-CIRES-DOE 20th Century Reanalysis (20CRv3). To do this, the Weather Research and Forecasting model (WRF) has been used to spatially downscale the reanalysis data to produce high-resolution 4 km (convection permitting) output for southcentral/southeastern Alaska. Five different physics parametrisations have been tested for the year 2010. The model output of these five configurations were evaluated using observational records from the Global Surface Summary of the Day (GSOD). The physics scheme that performed most realistically was identified using root mean square error, R squared and normalized mean error for temperature and precipitation. The study shows that 20CRv3 can successfully be downscaled for the study region. As a result, the leading parametrisation was used for a long-term simulation (179 years) to reconstruct local climate and weather over southern Alaska over a significant part of a tidewater glacier cycle. The results will be used to evaluate the influence of climate on these glaciers for the downscaling period from 1836 to 2015.
How does bias correction of regional climate model precipitation affect modelled runoff?
Publisher: Copernicus GmbH
Date: 04-02-2015
Abstract: Abstract. Many studies bias correct daily precipitation from climate models to match the observed precipitation statistics, and the bias corrected data are then used for various modelling applications. This paper presents a review of recent methods used to bias correct precipitation from regional climate models (RCMs). The paper then assesses four bias correction methods applied to the weather research and forecasting (WRF) model simulated precipitation, and the follow-on impact on modelled runoff for eight catchments in southeast Australia. Overall, the best results are produced by either quantile mapping or a newly proposed two-state gamma distribution mapping method. However, the differences between the methods are small in the modelling experiments here (and as reported in the literature), mainly due to the substantial corrections required and inconsistent errors over time (non-stationarity). The errors in bias corrected precipitation are typically lified in modelled runoff. The tested methods cannot overcome limitations of the RCM in simulating precipitation sequence, which affects runoff generation. Results further show that whereas bias correction does not seem to alter change signals in precipitation means, it can introduce additional uncertainty to change signals in high precipitation amounts and, consequently, in runoff. Future climate change impact studies need to take this into account when deciding whether to use raw or bias corrected RCM results. Nevertheless, RCMs will continue to improve and will become increasingly useful for hydrological applications as the bias in RCM simulations reduces.
Analysis and characterisation of extreme wind gust hazards in New South Wales, Australia
Publisher: Springer Science and Business Media LLC
Date: 11-03-2023
DOI: 10.1007/S11069-023-05887-1
Abstract: Extreme wind gusts cause major socioeconomic damage, and the rarity and localised nature of those events make their analysis challenging by either modelling or empirical approaches. A 23-year long data record from 29 automatic weather stations located in New South Wales (eastern Australia) is used to study the distribution, frequency and average recurrence intervals (ARIs) of extreme gusts via a peaks-over-threshold approach. We distinguish between gust events generated by synoptic phenomena (e.g. cyclones and frontal systems), hereafter called “synoptic events”, and convective phenomena (i.e. thunderstorms), hereafter called “convective events”, using the wind time series. For synoptic events the frequency of gusts $$ $$ 25 m/s decreases systematically inland from the coast, in contrast to convective gusts which are more uniformly distributed geographically and occur more often than synoptic gusts at nearly all inland locations. At inland locations the most extreme wind gusts are likewise dominated by convective events, whereas at coastal stations both gust types have similar intensities at low ARIs but convective events again dominate at the highest ARIs. Extreme gust directions were found to be predominantly westerly at inland locations and southerly at coastal ones, with more variable direction for convective than synoptic events. This study confirms the dominant role of thunderstorms in producing the most extreme gusts in the region, and shows that wind risk varies strongly with distance from the coast.
Introducing NARCliM1.5: Evaluation and projection of climate extremes for southeast Australia
Publisher: Elsevier BV
Date: 12-2022
The impact of dataset selection on land degradation assessment
Publisher: Elsevier BV
Date: 12-2018
Influence of cracking clays on satellite estimated and model simulated soil moisture
Publisher: Copernicus GmbH
Date: 18-06-2010
Abstract: Abstract. Vertisols are clay soils that are common in the monsoonal and dry warm regions of the world. One of the characteristics of these soil types is to form deep cracks during periods of extended dry, resulting in significant variation of the soil and hydrologic properties. Understanding the influence of these varying soil properties on the hydrological behavior of the system is of considerable interest, particularly in the retrieval or simulation of soil moisture. In this study we compare surface soil moisture (θ in m3 m−3) retrievals from AMSR-E using the VUA-NASA (Vrije Universiteit Amsterdam in collaboration with NASA) algorithm with simulations from the Community Land Model (CLM) over vertisol regions of mainland Australia. For the three-year period examined here (2003–2005), both products display reasonable agreement during wet periods. During dry periods however, AMSR-E retrieved near surface soil moisture falls below values for surrounding non-clay soils, while CLM simulations are higher. CLM θ are also higher than AMSR-E and their difference keeps increasing throughout these dry periods. To identify the possible causes for these discrepancies, the impacts of land use, topography, soil properties and surface temperature used in the AMSR-E algorithm, together with vegetation density and rainfall patterns, were investigated. However these do not explain the observed θ responses. Qualitative analysis of the retrieval model suggests that the most likely reason for the low AMSR-E θ is the increase in soil porosity and surface roughness resulting from cracking of the soil. To quantitatively identify the role of each factor, more in situ measurements of soil properties that can represent different stages of cracking need to be collected. CLM does not simulate the behavior of cracking soils, including the additional loss of moisture from the soil continuum during drying and the infiltration into cracks during rainfall events, which results in overestimated θ when cracks are present. The hydrological influence of soil physical changes are expected to propagate through the modeled system, such that modeled infiltration, evaporation, surface temperature, surface runoff and groundwater recharge should be interpreted with caution over these soil types when cracks might be present. Introducing temporally dynamic roughness and soil porosity into retrieval algorithms and adding a "cracking clay" module into models are expected to improve the representation of vertisol hydrology.
Robust historical evapotranspiration trends across climate regimes
Publisher: Copernicus GmbH
Date: 09-12-2020
Abstract: Abstract. Evapotranspiration (ET) links the hydrological, energy, and carbon cycle on the land surface. Quantifying ET and its spatiotemporal changes is also key to understanding climate extremes such as droughts, heatwaves and flooding. Regional ET estimates require reliable observationally-based gridded ET datasets, and while many have been developed using physically-based, empirically-based and hybrid techniques, their efficacy, and particularly the efficacy of their uncertainty estimates, is difficult to verify. In this work, we extend the methodology used in Hobeichi et al. (2018) to derive a new version of the Derived Optimal Linear Combination Evapotranspiration (DOLCE) product, with observationally constrained spatiotemporally varying uncertainty estimates, higher spatial resolution, more constituent products and extended temporal reach (1980–2018). After successful evaluation of the efficacy of these uncertainty estimates out-of-s le, we derive novel ET climatology clusters for the land surface, based on the magnitude and variability of ET at each location. The verified uncertainty estimates and extended time period then allow us to examine the robustness of historical trends spatially and in each of these six ET climatology clusters. We find that despite robust decreasing ET trends in some regions, these do not correlate with behavioural ET clusters. Each cluster, and the vast majority of the Earth's surface, show clear robust increases in ET over the recent historical period.
Pumice rafting and faunal dispersion during 2001–2002 in the Southwest Pacific: record of a dacitic submarine explosive eruption from Tonga
Publisher: Elsevier BV
Date: 10-2004
Multivariate bias correction of regional climate model boundary conditions
Publisher: Springer Science and Business Media LLC
Date: 10-03-2023
DOI: 10.1007/S00382-023-06718-6
Abstract: Improving modeling capacities requires a better understanding of both the physical relationship between the variables and climate models with a higher degree of skill than is currently achieved by Global Climate Models (GCMs). Although Regional Climate Models (RCMs) are commonly used to resolve finer scales, their application is restricted by the inherent systematic biases within the GCM datasets that can be propagated into the RCM simulation through the model input boundaries. Hence, it is advisable to remove the systematic biases in the GCM simulations prior to downscaling, forming improved input boundary conditions for the RCMs. Various mathematical approaches have been formulated to correct such biases. Most of the techniques, however, correct each variable independently leading to physical inconsistencies across the variables in dynamically linked fields. Here, we investigate bias corrections ranging from simple to more complex techniques to correct biases of RCM input boundary conditions. The results show that substantial improvements in model performance are achieved after applying bias correction to the boundaries of RCM. This work identifies that the effectiveness of increasingly sophisticated techniques is able to improve the simulated rainfall characteristics. An RCM with multivariate bias correction, which corrects temporal persistence and inter-variable relationships, better represents extreme events relative to univariate bias correction techniques, which do not account for the physical relationship between the variables.
Can Regional Climate Modeling Capture the Observed Changes in Spatial Organization of Extreme Storms at Higher Temperatures?
Publisher: American Geophysical Union (AGU)
Date: 12-05-2018
DOI: 10.1029/2018GL077716
A Markov chain method for weighting climate model ensembles
Publisher: Copernicus GmbH
Date: 11-06-2021
Abstract: Abstract. Climate change is typically modeled using sophisticated mathematical models (climate models) of physical processes that range in temporal and spatial scales. Multi-model ensemble means of climate models show better correlation with the observations than any of the models separately. Currently, an open research question is how climate models can be combined to create an ensemble mean in an optimal way. We present a novel stochastic approach based on Markov chains to estimate model weights in order to obtain ensemble means. The method was compared to existing alternatives by measuring its performance on training and validation data, as well as model-as-truth experiments. The Markov chain method showed improved performance over those methods when measured by the root mean squared error in validation and comparable performance in model-as-truth experiments. The results of this comparative analysis should serve to motivate further studies in applications of Markov chain and other nonlinear methods that address the issues of finding optimal model weight for constructing ensemble means.
A Markov chain method for weighting climate model ensembles
Publisher: Copernicus GmbH
Date: 10-2020
DOI: 10.5194/GMD-2020-253
Abstract: Abstract. Climate change is typically modelled using sophisticated mathematical models (Climate Models) of physical processes taking place over long periods of time. Multi-model ensembles of climate models show better correlation with the observations than any of the models separately. Currently, an open research question is how climate models can be combined to create an ensemble in an optimal way. We present a novel approach based on Markov chains to estimate model weights in order to obtain ensemble means. The method was compared to existing alternatives by measuring its performance on training and validation data. The Markov chain method showed improved performance over those methods when measured by the root mean squared error and the R-squared metrics. The results of this comparative analysis should serve to motivate further studies in Markov chain and other nonlinear methods application, that address the issues of finding optimal model weight for constructing ensemble means.
Dryland ecohydrology and climate change: critical issues and technical advances
Publisher: Copernicus GmbH
Date: 09-08-2012
DOI: 10.5194/HESS-16-2585-2012
Abstract: Abstract. Drylands cover about 40% of the terrestrial land surface and account for approximately 40% of global net primary productivity. Water is fundamental to the biophysical processes that sustain ecosystem function and food production, particularly in drylands where a tight coupling exists between ecosystem productivity, surface energy balance, biogeochemical cycles, and water resource availability. Currently, drylands support at least 2 billion people and comprise both natural and managed ecosystems. In this synthesis, we identify some current critical issues in the understanding of dryland systems and discuss how arid and semiarid environments are responding to the changes in climate and land use. The issues range from societal aspects such as rapid population growth, the resulting food and water security, and development issues, to natural aspects such as ecohydrological consequences of bush encroachment and the causes of desertification. To improve current understanding and inform upon the needed research efforts to address these critical issues, we identify some recent technical advances in terms of monitoring dryland water dynamics, water budget and vegetation water use, with a focus on the use of stable isotopes and remote sensing. These technological advances provide new tools that assist in addressing critical issues in dryland ecohydrology under climate change.
Comparison of prognostic and diagnostic surface flux modeling approaches over the Nile River basin
Publisher: American Geophysical Union (AGU)
Date: 2014
DOI: 10.1002/2013WR014194
Satellite based observations for seasonal snow cover detection and characterisation in Australia
Publisher: Elsevier BV
Date: 08-2012
Modeling the large-scale water balance impact of different irrigation systems
Publisher: American Geophysical Union (AGU)
Date: 08-2008
DOI: 10.1029/2007WR006671
Discrimination between climate and human-induced dryland degradation
Publisher: Elsevier BV
Date: 06-2004
Projected changes in vertical temperature profiles for Australasia
Publisher: Springer Science and Business Media LLC
Date: 30-07-2020
Estimating fire severity and carbon emissions over Australian tropical savannahs based on passive microwave satellite observations
Publisher: Informa UK Limited
Date: 17-04-2018
Diagnosing the seasonal land–atmosphere correspondence over northern Australia: dependence on soil moisture state and correspondence strength definition
Publisher: Copernicus GmbH
Date: 06-08-2015
DOI: 10.5194/HESS-19-3433-2015
Abstract: Abstract. The similarity of the temporal variations of land and atmospheric states during the onset (September) through to the peak (February) of the wet season over northern Australia is statistically diagnosed using ensembles of offline land surface model simulations that produce a range of different background soil moisture states. We derive the temporal correspondence between variations in the soil moisture and the planetary boundary layer via a statistical measure of rank correlation. The simulated evaporative fraction and the boundary layer are shown to be strongly correlated during both SON (September–October–November) and DJF (December–January–February) despite the differing background soil moisture states between the two seasons and among the ensemble members. The sign and magnitude of the boundary layer–surface layer soil moisture association during the onset of the wet season (SON) differs from the correlation between the evaporative fraction and boundary layer from the same season, and from the correlation between the surface soil moisture and boundary layer association during DJF. The patterns and magnitude of the surface flux–boundary layer correspondence are not captured when the relationship is diagnosed using the surface layer soil moisture alone. The conflicting results arise because the surface layer soil moisture lacks strong correlation with the atmosphere during the monsoon onset because the evapotranspiration is dominated by transpiration. Our results indicate that accurately diagnosing the correspondence and therefore coupling strength in seasonally dry regions, such as northern Australia, requires root zone soil moisture to be included.
The effect of different contributing sensors in IMERG-Final precipitation estimates
Publisher: Copernicus GmbH
Date: 03-03-2021
DOI: 10.5194/EGUSPHERE-EGU21-3575
Abstract: & & Ground observation absence in many parts of the world highlights the importance of merged satellite precipitation products. In this study, we aim to evaluate the effect of different sources of data in the uncertainties of a merged satellite product, by comparing the Integrated Multi-satellitE Retrievals for GPM (IMERG) final-product V06B with a ground-radar product, Multi-Radar Multi-Sensor (MRMS), over eastern United-States during the hurricane days that occurred in 2016-2018 using both pixel-based and object-based approaches. The results showed that IMERG had better agreement in terms of the average precipitation intensity and area when the passive microwave (PMW) sensor overpass is matched instantaneously with MRMS in comparison with the temporally averaged MRMS data (MRMS-Averaged) with a bias reduction of 75% and 65%, respectively. PMW observations tend to show storms with smaller areas in the IMERG final product in comparison with MRMS, possibly due to the effect of light precipitation not detected properly by PMW sensors. However, by removing the light precipitation (less than 1mm/hr) in the object-based approach, hurricane objects in the IMERG final product tend to be larger during the PMW observations, which might be related to different viewing angles of sensors contributing to MRMS and IMERG products. Precipitation estimates in the IMERG final product have smaller areas with higher average intensity during the PMW observations compared to data estimated by Morph or IR (morph/IR) observations. It is probably related to the effect of morphing technique, leading to homogenization of the varying rainstorm characteristics. The quality of IMERG data changes with the longer absence of the PMW observations. IMERG data estimated by morph/IR observations, with a 30-minute time-distance to the nearest PMW observation, showed the best agreement with MRMS-Averaged even in comparison with PMW estimates, possibly due to the time-lag in recording the precipitation between satellites and ground-radars. It is also possible to be related to the homogenizing nature of morphing technique in IMERG and averaging MRMS data in time in MRMS-Averaged, relaxing the differences between PMW observations and MRMS. However, the morph/IR data quality deteriorates with the longer absence of PMW sensors. The inter-comparison of PMW sensors showed the priority of imagers over sounders with GMI as the best among imagers and MHS as the best among sounders in terms of correlation and average intensity compared to MRMS however, SSMIS was the best in capturing the precipitation area.& &
Propagation of climate model biases to biophysical modelling can complicate assessments of climate change impact in agricultural systems
Publisher: Wiley
Date: 29-08-2019
DOI: 10.1002/JOC.5820
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