ORCID Profile
0000-0002-8320-4951
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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.
Physical oceanography | Biological oceanography | Chemical oceanography | Ecological Impacts of Climate Change | Oceanography | Oceanography | Biological Oceanography | Physical Oceanography
Ecosystem Assessment and Management of Coastal and Estuarine Environments | Coastal and Marine Management Policy | Marine Oceanic Processes (excl. climate related) |
Publisher: Elsevier
Date: 2019
Publisher: Copernicus GmbH
Date: 31-03-2016
Abstract: Abstract. In contrast to physical processes, biogeochemical processes are inherently patchy in the ocean, which affects both the observational s ling strategy and the representativeness of sparse measurements in data assimilating models. In situ observations from multiple glider deployments are analysed to characterize spatial scales of variability in both physical and biogeochemical properties, using an empirical statistical model. We find that decorrelation ranges are strongly dependent on the balance between local dynamics and mesoscale forcing. The shortest horizontal (5–10 km) and vertical (45 m) decorrelation ranges are for chlorophyll a fluorescence, whereas those variables that are a function of regional ocean and atmosphere dynamics (temperature and dissolved oxygen) result in anisotropic patterns with longer ranges along (28–37 km) than across the shelf (8–19 km). Variables affected by coastal processes (salinity and coloured dissolved organic matter) have an isotropic range similar to the baroclinic Rossby radius (10–15 km).
Publisher: Public Library of Science (PLoS)
Date: 17-03-2022
DOI: 10.1371/JOURNAL.PONE.0265593
Abstract: Physalia physalis , the bluebottle in Australia, are colonial siphonophores that live at the surface of the ocean, mainly in tropical and subtropical waters. P. physalis are sometimes present in large swarms, and with tentacles capable of intense stings, they can negatively impact public health and commercial fisheries. P. physalis , which does not swim, is advected by ocean currents and winds acting on its gas-filled sail. While previous studies have attempted to model the drift of P. physalis , little is known about its sources, distribution, and the timing of its arrival to shore. In this study, we present a dataset with four years of daily P. physalis beachings and stings reports at three locations off Sydney’s coast in Australia. We investigate the spatial and temporal variability of P. physalis presence (beachings and stings) in relation to different environmental parameters. This dataset shows a clear seasonal pattern where more P. physalis beachings occur in the Austral summer and less in winter. Cold ocean temperatures do not hinder the presence of P. physalis and the temperature seasonal cycle and that observed in P. physalis presence/absence time-series are out of phase by 3-4 months. We identify wind direction as the major driver of the temporal variability of P. physalis arrival to the shore, both at daily and seasonal time-scales. The differences observed between sites of the occurrence of beaching events is consistent with the geomorphology of the coastline which influences the frequency and direction of favorable wind conditions. We also show that rip currents, a physical mechanism occurring at the scale of the beach, can be a predictor of beaching events. This study is a first step towards understanding the dynamics of P. physalis transport and ultimately being able to predict its arrival to the coast and mitigating the number of people who experience painful stings and require medical help.
Publisher: American Geophysical Union (AGU)
Date: 2014
DOI: 10.1002/2013JC009284
Publisher: American Geophysical Union (AGU)
Date: 06-2017
DOI: 10.1002/2016JC011968
Publisher: Elsevier BV
Date: 2016
Publisher: American Geophysical Union (AGU)
Date: 02-2023
DOI: 10.1029/2022JC018689
Abstract: Continental shelves are key to societal interactions with the oceans, supporting % of the world's fisheries through highly productive ecosystems. Previous research has shown that phytoplankton biomass is generally higher on the inner continental shelves, often due to increased nutrient inputs from upwelling or coastal run‐off. However, consistency in observed vertical and horizontal gradients (in abundance, biomass or size) of larger particulates, including zooplankton, on continental shelves has not been established. Using an optical plankton counter and CTD mounted on an undulating towed body, we present high‐resolution vertically resolved profiles of pelagic particle size structure across a continental shelf. Biomass was highest inshore, declining with distance from shore and with depth in the top 100 m of the water column, although the presence of frontal zones can alter this pattern. In the region adjacent to the East Australian Current (EAC), uplift generated by either the EAC interacting with the continental slope or upwelling‐favorable winds, correlated with smaller geometric mean sizes and steeper size spectrum slopes, particularly in the presence of frontal features. South of the EAC separation, the continental shelf water mass was more homogenous but still displayed the same horizontal and vertical patterns in particulate biomass and mean size. By combining our observations in a global comparison, we demonstrate consistent particulate distributions on continental shelves where the inner shelf has higher biomass with a steeper size spectrum slope compared to offshore. The highly productive inner shelf supports zooplankton communities vital to temperate ecosystems and coastal fisheries, through their consistently high biomass.
Publisher: Springer Science and Business Media LLC
Date: 30-08-2016
Abstract: Since 2008, 26 glider missions have been undertaken along the continental shelf of southeastern Australia. Typically these missions have spanned the continental shelf on the inshore edge of the East Australian Current from 29.5–33.5 ° S. This comprehensive dataset of over 33,600 CTD profiles from the surface to within 10 m of the bottom in water depths ranging 25–200 m provides new and unprecedented high resolution observations of the properties of the continental shelf waters adjacent to a western boundary current, straddling the region where it separates from the coast. The region is both physically and biologically significant, and is also in a hotspot of ocean warming. We present gridded mean fields for temperature, salinity and density, but also dissolved oxygen and chlorophyll-a fluorescence indicative of phytoplankton biomass. This data will be invaluable for understanding shelf stratification, circulation, biophysical and bio-geochemical interactions, as well as for the validation of high-resolution ocean models or serving as teaching material.
Publisher: American Geophysical Union (AGU)
Date: 27-05-2017
DOI: 10.1002/2017GL073714
Publisher: Elsevier BV
Date: 04-2015
Publisher: American Geophysical Union (AGU)
Date: 03-2017
DOI: 10.1002/2016JC012241
Publisher: Elsevier BV
Date: 04-2020
Publisher: Frontiers Media SA
Date: 02-10-2019
Abstract: The OceanGliders program started in 2016 to support active coordination and enhancement of global glider activity. OceanGliders contributes to the international efforts of the Global Ocean Observation System (GOOS) for Climate, Ocean Health, and Operational Services. It brings together marine scientists and engineers operating gliders around the world: (1) to observe the long-term physical, biogeochemical, and biological ocean processes and phenomena that are relevant for societal applications and, (2) to contribute to the GOOS through real-time and delayed mode data dissemination. The OceanGliders program is distributed across national and regional observing systems and significantly contributes to integrated, multi-scale and multi-platform s ling strategies. OceanGliders shares best practices, requirements, and scientific knowledge needed for glider operations, data collection and analysis. It also monitors global glider activity and supports the dissemination of glider data through regional and global databases, in real-time and delayed modes, facilitating data access to the wider community. OceanGliders currently supports national, regional and global initiatives to maintain and expand the capabilities and application of gliders to meet key global challenges such as improved measurement of ocean boundary currents, water transformation and storm forecast.
Publisher: American Meteorological Society
Date: 05-2020
Abstract: Submesoscale lenses of water with anomalous hydrographic properties have previously been observed in the East Australian Current (EAC) system, embedded within the thermocline of mesoscale anticyclonic eddies. The waters within these lenses have high oxygen content and temperature–salinity properties that signify a surface origin. However, it is not known how these lenses form. This study presents field observations that provide insight into a possible generation mechanism via subduction at upper-ocean fronts. High-resolution hydrographic and velocity measurements of submesoscale activity were taken across a front between a mesoscale eddy dipole downstream of the EAC separation point. The front had O (1) Rossby number, strong vertical shear, and flow conducive to symmetric instability. Frontogenesis was measured in conjunction with subduction of an anticyclonic water parcel, indicative of intrathermocline eddy formation. Twenty-five years of satellite imagery reveals the existence of strong mesoscale strain coupled with strong temperature fronts in this region and indicates the conditions that led to frontal subduction observed here are a persistent feature. These processes impact the vertical export of tracers from the surface and dissipation of mesoscale kinetic energy, implicating their importance for understanding regional ocean circulation and biological productivity.
Publisher: American Meteorological Society
Date: 05-2013
Abstract: The cross-shelf dynamics up- and downstream of the separation of the South Pacific Ocean’s Western Boundary Current (WBC) are studied using two years of high-resolution velocity and temperature measurements from mooring arrays. The shelf circulation is dominated by the East Australian Current (EAC) and its eddy field, with mean poleward depth-integrated magnitudes on the shelf break of 0.35 and 0.15 m s−1 up- and downstream of the separation point, respectively. The high cross-shelf variability is analyzed though a momentum budget, showing a dominant geostrophic balance at both locations. Among the secondary midshelf terms, the bottom stress influence is higher upstream of the separation point while the wind stress is dominant downstream. This study investigates the response of the velocity and temperature cross-shelf structure to both wind and EAC intrusions. Despite the deep water (up to 140 m), the response to a dominant along-shelf wind stress forcing is a classic two-layer Ekman structure. During weak winds, the shelf encroachment of the southward current drives an onshore Ekman flow in the bottom boundary layer. Both the bottom velocity and the resultant bottom cross-shelf temperature gradient are proportional to the magnitude of the encroaching current, with similar linear regressions up- and downstream of the WBC separation. The upwelled water is then subducted below the EAC upstream of the separation point. Such current-driven upwelling is shown to be the dominant driver of cold water uplift in the EAC-dominated region, with significant impacts expected on nutrient enrichment and thus on biological productivity.
Publisher: American Geophysical Union (AGU)
Date: 11-2017
DOI: 10.1002/2017JC013097
Publisher: American Geophysical Union (AGU)
Date: 07-09-2021
DOI: 10.1029/2021GL094785
Abstract: Although the impacts of marine heatwaves (MHWs) can extend well below the ocean surface, little is known about how oceanic and atmospheric forcings control their vertical structure. Here, we relate the MHW drivers to their sub‐surface characteristics in different dynamical regimes including the East Australia Current. We detect MHWs in the depth‐dependent surface mixed layer over 30‐years and use a heat budget to identify the dominant mechanisms driving them. We show that MHWs in the Western Boundary Current (WBC) jet are predominantly driven by air‐sea heatflux whilst in the WBC extension, MHWs are advection‐driven. The deepest and longest MHWs are advection‐driven and are more prevalent in autumn and winter. Surface (latent) flux‐driven MHWs are shallower and occur predominantly in summer. Demonstrating how MHW characteristics are linked to their drivers facilitates their prediction through driver diagnosis, especially below the surface where observations are sparse and ecological impact is high.
Publisher: American Meteorological Society
Date: 10-2014
Publisher: American Geophysical Union (AGU)
Date: 04-2023
DOI: 10.1029/2022JC019361
Abstract: Understanding the distribution of chlorophyll on the continental shelves adjacent to western boundary currents is important, both from an ecosystem perspective, as well as for their role as a net sink of atmospheric CO 2 . However, in‐situ observations of chlorophyll in these dynamic regions are rare. Here, using more than a decade of underwater glider observations from 29 deployments in the East Australian Current (EAC) system, we examine the effect of the mesoscale western boundary current (WBC) circulation on chlorophyll distribution across the shelf. The extensive hydrographic dataset reveals that the mode of boundary current separation has a strong persistent spatial influence on both the stratification and chlorophyll distribution on the shelf between 31.5° and 34°S, a productive area adjacent to the EAC separation zone. We identify that subsurface chlorophyll maxima are common, and their depth and strength is dictated by the offshore mesoscale circulation associated with the WBC separation. The vertical chlorophyll distribution is modulated by the combination of the seasonal cycle and the sporadic influence of mesoscale eddies associated with WBC jet separation. Of the three dominant WBC separation scenarios, eddy dipoles result in shelf waters that are on average more stratified, have higher chlorophyll values, and a deeper chlorophyll maximum compared to other circulation modes. These results suggest that it is necessary to consider the influence of WBC dynamics on chlorophyll concentrations for accurate estimates of atmospheric CO 2 uptake.
Publisher: American Geophysical Union (AGU)
Date: 02-2020
DOI: 10.1029/2019JC015613
Abstract: In western boundary current systems, sharp velocity gradients between the poleward flowing jet and coastal waters generally act to inhibit cross‐shelf exchange. Downstream of jet separation, dynamic mesoscale eddies dominate the flow. In the East Australian Current System, counter‐rotating eddy dipoles are often present which, in the appropriate configuration, have potential to drive cross‐shelf transport. However, this eddy dipole mode is poorly understood in the framework of cross‐shelf exchange and the effect of these structures on shelf waters is uncertain. Using 25 years of satellite altimetry, as well as in situ s ling of a typical dipole event, we investigate the characteristics of eddy‐driven cross‐shelf exchange. We show that the maximum onshore velocity is driven by an eddy dipole structure and occurs in a defined latitudinal band between 33°S and 34°S more than 50% of the time. We s le a typical eddy dipole and find a strong onshore jet, 37 km wide, with velocities up to 1.78 m s and a transport of at least 16 Sv. Hydrographic data from an autonomous underwater glider show that this jet manifests on the shelf as a subsurface intrusion of warm salty water extending from offshore up onto the midshelf. In the light of climatic changes in western boundary current transport and the increase in their eddy kinetic energy, understanding eddy‐driven cross‐shelf exchange is important to predict future changes to the shelf water mass.
Publisher: Elsevier BV
Date: 08-2015
Publisher: Springer Science and Business Media LLC
Date: 07-04-2022
DOI: 10.1038/S41597-022-01224-6
Abstract: Multi-decadal ocean time-series are fundamental baselines for assessing the impacts of environmental change, however, compiling and quality controlling historic data from multiple sources remains challenging. Here we aggregate, document, and release a number of long time-series temperature products and climatologies compiled from data obtained at 4 monitoring sites around Australia where sub-surface ocean temperature has been recorded nominally weekly to monthly since the 1940s/50s. In recent years, the s ling was augmented with data obtained from moored sensors, vertical profiles and satellite-derived data. The temperature data have been quality controlled, and combined using a rigorously tested methodology. We have packaged the multi-decadal, multi-depth, multi-platform temperature time-series at each site and produced a range of daily temperature climatologies from different data combinations and time periods. The 17 data products are provided as CF-compliant NetCDF files and will be updated periodically. The long-term temperature time-series will be useful for studies of ocean temperature variability, trends, anomalies and change. The data collection is supported by Australia’s Integrated Marine Observing System and data are open-access.
Publisher: Elsevier
Date: 2015
Publisher: Copernicus GmbH
Date: 19-09-2016
Abstract: Abstract. The technical steps involved in configuring a regional ocean model are analogous for all community models. All require the generation of a model grid, preparation and interpolation of topography, initial conditions, and forcing fields. Each task in configuring a regional ocean model is straightforward – but the process of downloading and reformatting data can be time-consuming. For an experienced modeller, the configuration of a new model domain can take as little as a few hours – but for an inexperienced modeller, it can take much longer. In pursuit of technical efficiency, the Australian ocean modelling community has developed the Web-based MARine Virtual Laboratory (WebMARVL). WebMARVL allows a user to quickly and easily configure an ocean general circulation or wave model through a simple interface, reducing the time to configure a regional model to a few minutes. Through WebMARVL, a user is prompted to define the basic options needed for a model configuration, including the model, run duration, spatial extent, and input data. Once all aspects of the configuration are selected, a series of data extraction, reprocessing, and repackaging services are run, and a “take-away bundle” is prepared for download. Building on the capabilities developed under Australia's Integrated Marine Observing System, WebMARVL also extracts all of the available observations for the chosen time–space domain. The user is able to download the take-away bundle and use it to run the model of his or her choice. Models supported by WebMARVL include three community ocean general circulation models and two community wave models. The model configuration from the take-away bundle is intended to be a starting point for scientific research. The user may subsequently refine the details of the model set-up to improve the model performance for the given application. In this study, WebMARVL is described along with a series of results from test cases comparing WebMARVL-configured models to observations and manually configured models. It is shown that the automatically configured model configurations produce a good starting point for scientific research.
Publisher: Elsevier BV
Date: 09-2019
Publisher: American Geophysical Union (AGU)
Date: 05-2017
DOI: 10.1002/2016JC012171
Abstract: The East Australian Current (EAC) dominates the ocean circulation along south‐eastern Australia, however, little is known about the submesoscale frontal instabilities associated with this western boundary current. One year of surface current measurements from HF radars, in conjunction with mooring and satellite observations, highlight the occurrence and propagation of meanders and frontal eddies along the inshore edge of the EAC. Eddies were systematically identified using the geometry of the high spatial resolution (∼1.5 km) surface currents, and tracked every hour. Cyclonic eddies were observed irregularly, on average every 7 days, with inshore radius ∼10 km. Among various forms of structures, frontal eddies associated with EAC meanders were characterized by poleward advection speeds of ∼0.3–0.4 m/s, migrating as far as 500 km south, based on satellite imagery. Flow field kinematics show that cyclonic eddies have high Rossby numbers (0.6–1.9) and enhance particle dispersion. Patches of intensified surface ergence at the leading edge of the structures are expected to generate vertical uplift. This is confirmed by subsurface measurements showing temperature uplift of up to 55 m over 24 h and rough estimates of vertical velocities of 10s of meters per day. While frontal eddies propagate through the radar domain independently of local wind stress, upfront wind can influence their stalling and growth, and can also generate large cold core eddies through intense shear. Such coherent structures are a major mechanism for the transport and entrainment of nutrient rich coastal or deep waters, influencing physical and biological dynamics, and connectivity over large distances.
Publisher: American Geophysical Union (AGU)
Date: 13-01-2015
DOI: 10.1002/2014GL062260
Publisher: Elsevier BV
Date: 03-2014
Publisher: Springer Science and Business Media LLC
Date: 09-2023
Publisher: Frontiers Media SA
Date: 30-07-2020
No related organisations have been discovered for amandine schaeffer.
Start Date: 07-2023
End Date: 06-2026
Amount: $693,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 10-2022
End Date: 10-2025
Amount: $441,371.00
Funder: Australian Research Council
View Funded Activity