ORCID Profile
0000-0003-1258-5002
Current Organisation
CSIRO Oceans and Atmosphere
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Publisher: The Open Journal
Date: 21-01-2019
DOI: 10.21105/JOSE.00037
Publisher: Springer Science and Business Media LLC
Date: 23-02-2022
DOI: 10.1038/S41586-021-04370-W
Abstract: Warming-induced global water cycle changes pose a significant challenge to global ecosystems and human society. However, quantifying historical water cycle change is difficult owing to a dearth of direct observations, particularly over the ocean, where 77% and 85% of global precipitation and evaporation occur, respectively
Publisher: American Meteorological Society
Date: 16-08-2016
Abstract: The Pacific–South American (PSA) pattern is an important mode of climate variability in the mid-to-high southern latitudes. It is widely recognized as the primary mechanism by which El Niño–Southern Oscillation (ENSO) influences the southeast Pacific and southwest Atlantic and in recent years has also been suggested as a mechanism by which longer-term tropical sea surface temperature trends can influence the Antarctic climate. This study presents a novel methodology for objectively identifying the PSA pattern. By rotating the global coordinate system such that the equator (a great circle) traces the approximate path of the pattern, the identification algorithm utilizes Fourier analysis as opposed to a traditional empirical orthogonal function approach. The climatology arising from the application of this method to ERA-Interim reanalysis data reveals that the PSA pattern has a strong influence on temperature and precipitation variability over West Antarctica and the Antarctic Peninsula and on sea ice variability in the adjacent Amundsen, Bellingshausen, and Weddell Seas. Identified seasonal trends toward the negative phase of the PSA pattern are consistent with warming observed over the Antarctic Peninsula during autumn, but are inconsistent with observed winter warming over West Antarctica. Only a weak relationship is identified between the PSA pattern and ENSO, which suggests that the pattern might be better conceptualized as a preferred regional atmospheric response to various external (and internal) forcings.
Publisher: American Geophysical Union (AGU)
Date: 15-05-2019
DOI: 10.1029/2019GL082015
Publisher: IOP Publishing
Date: 02-06-2023
Abstract: The record-shattering hot day in the Pacific Northwest in June 2021 is used to motivate a study of record-shattering temperature extremes in a very large hindcast ensemble. The hottest days in the Pacific Northwest in the large ensemble have similar large scale and synoptic patterns to those associated with the observed event. From the perspective of a fixed location, the hottest ensemble days are acutely sensitive to the chance sequencing of a dry period with a precisely positioned weather pattern. These days are thus rare and require very large s les (tens of thousands of years) to capture. The enduring nature of record-shattering heat records can be understood through this lens of weather ‘noise’ and s ling. When a record-shattering event occurs due to chance alignment of weather systems in the optimal configuration, any small s le of years subsequent to the (very unlikely) record event has an extremely low chance of finding yet another chance extreme. While warming of the baseline climate can narrow the gap between more regular extremes and record-shattering extremes, this can take many decades depending on the pace of climate change. Climate models are unlikely to capture record-shattering extremes at fixed locations given by observations unless the model s les are large enough to provide enough weather outcomes to include the optimal weather alignments. This underscores the need to account for s ling in assessing models and changes in weather-sensitive extremes. In particular, climate models are not necessarily deficient in representing extremes if that assessment is based on their absence in undersize s les.
Publisher: Authorea, Inc.
Date: 20-07-2023
DOI: 10.22541/ESSOAR.168987142.28631718/V1
Abstract: Greenhouse gases and aerosols play a major role in controlling global climate change. Greenhouse gases drive a radiative imbalance which warms the ocean, while aerosols cool the ocean. Since 1980, the effective radiation felt by the planet due to anthropogenic aerosols has levelled off, global ocean cooling due to aerosols has decelerated, and greenhouse gas-driven ocean warming has accelerated. We explore the deceleration of aerosol-driven ocean cooling by quantifying a time- and spatially-varying ocean heat uptake efficiency, defined as the change in the rate of global ocean heat storage per degree of cooling surface temperature. In aerosol-only simulations, ocean heat uptake efficiency has decreased by 69% since the 1900s. The tropics and sub-tropics have driven this decrease, while the coldest fraction of the ocean continues to sustain cooling and high ocean heat uptake efficiency. Our results identify a growing trend towards less efficient ocean cooling due to aerosols.
Publisher: MDPI AG
Date: 15-06-2022
DOI: 10.3390/CLI10060083
Abstract: With increased interest in climate forecasts and projections, it is important to understand more about their sources and levels of skill. A starting point here is to describe the nature of the skill associated with forecasts and projections. Climate forecasts and projections typically both include time varying forcing of the climate, but only forecasts have initial conditions set close to the observed climate state. Climate forecasts therefore derive skill from both initial conditions and from forcing. The character of the initial condition skill and forcing skill is different. Skill from initial conditions results in a narrowing of expectations relative to a climatological distribution and points toward a more favoured part of the distribution. Forcing skill could result from a shift in the preferred parts of the climatological distribution in response to forcing, or it could result from a shift in the entire distribution, or both. Assessments of forcing skill require time averages of the target variable that are long enough so that the contributions from internal variations are small compared to the forced response. The assessment of skill of climate forecasts and projections is inherently partial because of the small number of repeated trials possible on typical climate time scales but is nonetheless the only direct measure of their performance.
Publisher: American Meteorological Society
Date: 12-2015
Abstract: Southern Hemisphere mid- to upper-tropospheric planetary wave activity is characterized by the superposition of two zonally oriented, quasi-stationary waveforms: zonal wavenumber 1 (ZW1) and zonal wavenumber 3 (ZW3). Previous studies have tended to consider these waveforms in isolation and with the exception of those studies relating to sea ice, little is known about their impact on regional climate variability. A novel approach is taken to quantifying the combined influence of ZW1 and ZW3, using the strength of the hemispheric meridional flow as a proxy for zonal wave activity. The methodology adapts the wave envelope construct routinely used in the identification of synoptic-scale Rossby wave packets and improves on existing approaches by allowing for variations in both wave phase and litude. While ZW1 and ZW3 are both prominent features of the climatological circulation, the defining feature of highly meridional hemispheric states is an enhancement of the ZW3 component. Composites of the mean surface conditions during these highly meridional, ZW3-like anomalous states (i.e., months of strong planetary wave activity) reveal large sea ice anomalies over the Amundsen and Bellingshausen Seas during autumn and along much of the East Antarctic coastline throughout the year. Large precipitation anomalies in regions of significant topography (e.g., New Zealand, Patagonia, and coastal Antarctica) and anomalously warm temperatures over much of the Antarctic continent were also associated with strong planetary wave activity. The latter has potentially important implications for the interpretation of recent warming over West Antarctica and the Antarctic Peninsula.
Publisher: American Meteorological Society
Date: 26-08-2020
Abstract: Coupled climate models are prone to ‘drift’ (long-term unforced trends in state variables) due to incomplete spin-up and non-closure of the global mass and energy budgets. Here we assess model drift and the associated conservation of energy, mass and salt in CMIP6 and CMIP5 models. For most models, drift in globally-integrated ocean mass and heat content represents a small but non-negligible fraction of recent historical trends, while drift in atmospheric water vapor is negligible. Model drift tends to be much larger in time-integrated ocean heat and freshwater flux, net top-of-the-atmosphere radiation (netTOA) and moisture flux into the atmosphere (evaporation minus precipitation), indicating a substantial leakage of mass and energy in the simulated climate system. Most models are able to achieve approximate energy budget closure after drift is removed, but ocean mass budget closure eludes a number of models even after de-drifting and none achieve closure of the atmospheric moisture budget. The magnitude of the drift in the CMIP6 ensemble represents an improvement over CMIP5 in some cases (salinity and time-integrated netTOA) but is worse (time-integrated ocean freshwater and atmospheric moisture fluxes) or little changed (ocean heat content, ocean mass and time-integrated ocean heat flux) for others, while closure of the ocean mass and energy budgets after drift removal has improved.
Publisher: Elsevier BV
Date: 05-2006
DOI: 10.1016/J.JSAMS.2006.02.004
Abstract: Chronic plantar heel pain (CPHP) is one of the most common soft tissue disorders of the foot, yet its aetiology is poorly understood. The purpose of this systematic review was to examine the association between CPHP and the various aetiological factors reported in the literature. Seven electronic databases and the reference lists of key articles were searched in August 2005. The resulting list of articles was assessed by two independent reviewers according to pre-determined selection criteria and a final list of articles for review was created. The methodological quality of the included articles was assessed and the evidence presented in each of the articles was descriptively analysed. From the 16 included articles, body mass index in a non-athletic population and the presence of calcaneal spur were the two factors found to have an association with CPHP. Increased weight in a non athletic population, increased age, decreased ankle dorsiflexion, decreased first metatarsophalangeal joint extension and prolonged standing all demonstrated some evidence of an association with CPHP. Evidence for static foot posture and dynamic foot motion was inconclusive and height, weight and BMI in an athletic population were not associated with CPHP. The findings of this review should be used to guide the focus of prospective cohort studies, the results of which would ultimately provide a list of risk factors for CPHP. Such a list is essential in the development of new and improved preventative and treatment strategies for CPHP.
Publisher: Inter-Research Science Center
Date: 24-01-2012
DOI: 10.3354/CR01046
Publisher: Springer Science and Business Media LLC
Date: 25-03-2022
DOI: 10.1038/S41612-022-00248-4
Abstract: Wildfire can cause significant adverse impacts to society and the environment. Weather and climate play an important role in modulating wildfire activity. We explore the joint occurrence of global fire weather and meteorological drought using a compound events framework. We show that, for much of the globe, burned area increases when periods of heightened fire weather compound with dry antecedent conditions. Regions associated with wildfire disasters, such as southern Australia and the western USA, are prone to experiencing years of compound drought and fire weather. Such compound events have increased in frequency for much of the globe, driven primarily by increases in fire weather rather than changes in precipitation. El Ni $$\\tilde{{{{\\rm{n}}}}}$$ n ̃ o Southern Oscillation is associated with widespread, spatially compounding drought and fire weather. In the Northern Hemisphere, a La Ni $$\\tilde{{{{\\rm{n}}}}}$$ n ̃ a signature is evident, whereas El Ni $$\\tilde{{{{\\rm{n}}}}}$$ n ̃ o is associated with such events in the tropics and, to a lesser degree, the Southern Hemisphere. Other climate modes and regional patterns of atmospheric circulation are also important, depending on the region. We show that the lengths of the fire weather seasons in eastern Australia and western North America have increased substantially since 2000, raising the likelihood of overlapping fire weather events in these regions. These cross-hemispheric events may be linked to the occurrence of El Ni $$\\tilde{{{{\\rm{n}}}}}$$ n ̃ o, although the sea-surface temperature magnitudes are small. Instead, it is likely that anthropogenic climate change is the primary driver of these changes.
Publisher: American Meteorological Society
Date: 07-2016
DOI: 10.1175/BAMS-D-15-00010.1
Abstract: Weather and climate science has undergone a computational revolution in recent decades, to the point where all modern research relies heavily on software and code. Despite this profound change in the research methods employed by weather and climate scientists, the reporting of computational results has changed very little in relevant academic journals. This lag has led to something of a reproducibility crisis, whereby it is impossible to replicate and verify most of today’s published computational results. While it is tempting to simply decry the slow response of journals and funding agencies in the face of this crisis, there are very few ex les of reproducible weather and climate research upon which to base new communication standards. In an attempt to address this deficiency, this essay describes a procedure for reporting computational results that was employed in a recent Journal of Climate paper. The procedure was developed to be consistent with recommended computational best practices and seeks to minimize the time burden on authors, which has been identified as the most important barrier to publishing code. It should provide a starting point for weather and climate scientists looking to publish reproducible research, and it is proposed that journals could adopt the procedure as a minimum standard.
Publisher: Springer Science and Business Media LLC
Date: 17-05-2007
Abstract: Chronic plantar heel pain (CPHP) is one of the most common musculoskeletal disorders of the foot, yet its aetiology is poorly understood. The purpose of this study was to examine the association between CPHP and a number of commonly hypothesised causative factors. Eighty participants with CPHP (33 males, 47 females, mean age 52.3 years, S.D. 11.7) were matched by age (± 2 years) and sex to 80 control participants (33 males, 47 females, mean age 51.9 years, S.D. 11.8). The two groups were then compared on body mass index (BMI), foot posture as measured by the Foot Posture Index (FPI), ankle dorsiflexion range of motion (ROM) as measured by the Dorsiflexion Lunge Test, occupational lower limb stress using the Occupational Rating Scale and calf endurance using the Standing Heel Rise Test. Univariate analysis demonstrated that the CPHP group had significantly greater BMI (29.8 ± 5.4 kg/m 2 vs. 27.5 ± 4.9 kg/m 2 P 0.01), a more pronated foot posture (FPI score 2.4 ± 3.3 vs. 1.1 ± 2.3 P 0.01) and greater ankle dorsiflexion ROM (45.1 ± 7.1° vs. 40.5 ± 6.6° P 0.01) than the control group. No difference was identified between the groups for calf endurance or time spent sitting, standing, walking on uneven ground, squatting, climbing or lifting. Multivariate logistic regression revealed that those with CPHP were more likely to be obese (BMI ≥ 30 kg/m 2 ) (OR 2.9, 95% CI 1.4 – 6.1, P 0.01) and to have a pronated foot posture (FPI ≥ 4) (OR 3.7, 95% CI 1.6 – 8.7, P 0.01). Obesity and pronated foot posture are associated with CPHP and may be risk factors for the development of the condition. Decreased ankle dorsiflexion, calf endurance and occupational lower limb stress may not play a role in CPHP.
Publisher: Inter-Research Science Center
Date: 20-10-2011
DOI: 10.3354/CR01028
Publisher: Wiley
Date: 07-02-2014
DOI: 10.1002/JOC.3916
Publisher: American Geophysical Union (AGU)
Date: 24-04-2021
DOI: 10.1029/2020GL091439
Abstract: The ocean has absorbed approximately 90% of the accumulated heat in the climate system since 1970. As global warming accelerates, understanding ocean heat content changes and tracing these to surface heat input is increasingly important. We introduce a novel framework by organizing the ocean into temperature‐percentiles from warmest to coldest, allowing us to trace ocean temperature changes to changes in surface fluxes and mixing. Applying this framework to observations and historical CMIP6 simulations, we find that 50 ± 6% of surface heat uptake between 1970 and 2014 is confined to isotherms in the coldest 90% of the ocean volume. These isotherms outcrop over only 23% of the ocean's surface area in the sub‐polar regions, implying a disproportionately large heat input per unit area. Additionally, a cooling bias in the CMIP6 models is traced to inaccurate sea surface temperatures and surface heat fluxes into the warmest 5%–20% of the ocean volume.
Publisher: Public Library of Science (PLoS)
Date: 03-2018
Publisher: CSIRO Publishing
Date: 22-03-2023
DOI: 10.1071/ES22034
Abstract: In eastern Australia we expect to experience wet conditions during La Niña and dry during El Niño events. We explore how well these expectations match historical outcomes by assessing, for spring, how much rain fell during past La Niña and El Niño events. We use a tercile framing and find that for rainfall averaged across eastern Australia, La Niña approximately doubles the chance of spring rainfall being in the wet tercile whereas El Niño approximately doubles the chance of a dry spring. Also of note is that during La Niña, the dry tercile is mostly vacant and during El Niño, the wet tercile is mostly vacant, indicating that one should not expect dry conditions in La Niña or wet in El Niño for eastern Australia as a whole. At in idual locations across Australia, the results vary, and in some cases, including the eastern seaboard, La Niña or El Niño events do not change the odds of wet and dry springs significantly beyond chance expectations. For ex le, in the Sydney region, the normal chance of experiencing a wet tercile spring is 33% and this increases only slightly in a La Niña to 38%, suggesting that La Niña is not a strong indicator for wet conditions in this region. These outcomes may help to manage our expectations for the likely rainfall outcomes during future El Niño–Southern Oscillation (ENSO) events.
Publisher: American Meteorological Society
Date: 15-10-2010
Abstract: Mesoscale cyclones play an important role in the weather and climate of the Southern Hemisphere (SH) mid-to-high latitudes. However, the relatively small size and short lifetime of these systems, combined with the lack of available conventional data in this region, means that there is a poor understanding of their climatological characteristics. In this study, the University of Melbourne cyclone-finding algorithm was applied to relatively high-resolution scatterometer-derived surface pressure fields, obtained from the Department of Atmospheric Sciences at the University of Washington, to produce a decade-long (1999–2008) seasonal climatology of mesoscale cyclone activity over the ice-free regions of the Southern Ocean. The frequency of mesoscale cyclone activity was found to be highest just to the north of the sea ice zone, reaching a maximum over the Amundsen and Bellingshausen Seas (ABS), while the southern Indian Ocean was associated with systems of the largest depth, intensity, and momentum flux at the ocean surface. These spatial patterns in mean mesoscale cyclone characteristics showed a broad resemblance to those reported in existing synoptic-scale cyclone climatologies. Maximum wind speed data indicated that SH polar lows may be more frequent than the current literature suggests, while strong positive trends identified in mesoscale cyclone frequency over the ABS may represent a contributing factor to the rapid warming observed in that region over recent years. Partial correlation analyses indicated a link between mesoscale cyclone frequency and the southern annular mode.
No related grants have been discovered for Damien Irving.