ORCID Profile
0000-0002-4455-801X
Current Organisations
NASA Marshall Space Flight Center
,
Commonwealth Scientific and Industrial Research Organisation
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
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.
Palaeoclimatology | Geomorphology and Regolith and Landscape Evolution | Physical Oceanography | Oceanography
Antarctic and Sub-Antarctic Oceanography | Climate Change Models | Global Effects of Climate Change and Variability (excl. Australia, New Zealand, Antarctica and the South Pacific) (excl. Social Impacts) |
Publisher: American Geophysical Union (AGU)
Date: 08-2016
DOI: 10.1002/2016JC011687
Publisher: American Geophysical Union (AGU)
Date: 04-2015
DOI: 10.1002/2015JC010697
Abstract: Antarctic ice sheet mass loss has been linked to an increase in oceanic heat supply, which enhances basal melt and thinning of ice shelves. Here we detail the interaction of modified Circumpolar Deep Water (mCDW) with the Amery Ice Shelf, the largest ice shelf in East Antarctica, and provide the first estimates of basal melting due to mCDW. We use subice shelf ocean observations from a borehole site (AM02) situated ∼70 km inshore of the ice shelf front, together with open ocean observations in Prydz Bay. We find that mCDW transport into the cavity is about 0.22 ± 0.06 Sv (1 Sv = 10 6 m 3 s −1 ). The inflow of mCDW drives a net basal melt rate of up to 2 ± 0.5 m yr −1 during 2001 (23.9 ± 6.52 Gt yr −1 from under about 12,800 km 2 of the north‐eastern flank of the ice shelf). The heat content flux by mCDW at AM02 shows high intra‐annual variability (up to 40%). Our results suggest two main modes of subice shelf circulation and basal melt regimes: (1) the “ice pump”/high salinity shelf water circulation, on the western flank and (2) the mCDW meltwater‐driven circulation in conjunction with the “ice pump,” on the eastern flank. These results highlight the sensitivity of the Amery's basal melting to changes in mCDW inflow. Improved understanding of such ice shelf‐ocean interaction is crucial to refining projections of mass loss and associated sea level rise.
Publisher: American Geophysical Union (AGU)
Date: 12-2021
DOI: 10.1029/2021JC017748
Abstract: We provide a detailed description of the spatial distribution, seasonality and transformation of the main water masses within MacKenzie Polynya (MP) in Prydz Bay, East Antarctica, using data from instrumented southern elephant seals. Dense Shelf Water (DSW) formation in MP shows large spatial variability that is related to the (a) local bathymetry, (b) water column preconditioning from the presence/absence of different water masses, and (c) proximity to the Amery Ice Shelf meltwater outflow. MP exhibits sustained sea ice production and brine rejection (thus, salinity increase) from April to October. However, new DSW is only formed from June onward, when the mixed layer deepens and convection is strong enough to break the stratification set by Antarctic Surface Water above and Ice Shelf Water below. We found no evidence of DSW export from MP to Darnley polynya, as previously suggested. Rather, our observations suggest some DSW formed in Darnley Polynya may drain toward the western Prydz Bay. Then, DSW is exported offshore from Prydz Bay through the Prydz Channel. The interplay between sea ice formation, meltwater input, and sea floor topography is likely to explain why some coastal polynyas form more DSW than others, as well as the temporal variability in DSW formation within a particular polynya.
Publisher: Wiley
Date: 05-2016
DOI: 10.1002/ECS2.1213
Publisher: American Geophysical Union (AGU)
Date: 30-07-2021
DOI: 10.1029/2020JC016998
Abstract: Antarctic Bottom Water (AABW) production supplies the deep limb of the global overturning circulation and ventilates the deep ocean. While the Weddell and Ross Seas are recognized as key sites for AABW production, additional sources have been discovered in coastal polynya regions around East Antarctica, most recently at Vincennes Bay. Vincennes Bay, despite encompassing two distinct polynya regions, is considered the weakest source, producing Dense Shelf Water (DSW) only just dense enough to contribute to the lighter density classes of AABW found offshore. Here we provide the first detailed oceanographic observations of the continental shelf in Vincennes Bay (104‐111°E), using CTD data from instrumented elephant seals spanning from February to November of 2012. We find that Vincennes Bay has East Antarctica’s warmest recorded intrusions of modified Circumpolar Deep Water (mCDW) and that warm mCDW drives basal melt under Vanderford and Underwood ice shelves. Our study also provides the first direct observational evidence for the inflow of meltwater to this region, which increases stratification and hinders DSW formation, and thus AABW production. The Vincennes Bay glaciers, together with the Totten Glacier, drain part of the Aurora Basin, which holds up to 7 m of sea level rise equivalent. Our results highlight the vulnerability of the East Antarctic Ice Sheet to intrusions of mCDW.
Publisher: Springer Science and Business Media LLC
Date: 26-02-2020
Publisher: American Geophysical Union (AGU)
Date: 04-2010
DOI: 10.1029/2008JC005146
Publisher: American Astronomical Society
Date: 31-07-2023
Publisher: Elsevier BV
Date: 02-2014
Publisher: American Geophysical Union (AGU)
Date: 29-11-2022
DOI: 10.1029/2022JC018804
Abstract: Coastal polynyas are key formation regions for dense shelf water (DSW) that ultimately contributes to the ventilation of the ocean abyss. However, not all polynyas form DSW. We examine how the physiographic setting, water‐mass distribution and transformation, water column stratification, and sea‐ice production regulate DSW formation in four East Antarctic coastal polynyas. We use a salt budget to estimate the relative contribution of sea‐ice production and lateral advection to the monthly change in salinity in each polynya. DSW forms in Mackenzie polynya due to a combination of physical features (shallow water depth and a broad continental shelf) and high sea‐ice production. Sea‐ice formation begins early (March) in Mackenzie polynya, counteracting fresh advection and establishing a salty mixed layer in autumn that preconditions the water column for deep convection in winter. Sea‐ice production is moderate in the other three polynyas, but saline DSW is not formed (a fresh variety is formed in the Barrier polynya). In the Shackleton polynya, brine rejection during winter is insufficient to overcome the very fresh autumn mixed layer. In Vincennes Bay, a strong inflow of modified Circumpolar Deep Water stratifies the water column, hindering deep convection and DSW formation. Our study highlights that DSW formation in a given polynya depends on a complex combination of factors, some of which may be strongly altered under a changing climate, with potentially important consequences for the ventilation of the deep ocean, the global meridional overturning circulation, and the transport of ocean heat to Antarctic ice shelves.
Publisher: American Geophysical Union (AGU)
Date: 08-2020
DOI: 10.1029/2020JC016113
Publisher: American Astronomical Society
Date: 31-07-2023
Publisher: American Geophysical Union (AGU)
Date: 13-06-2019
DOI: 10.1029/2019GL082850
Publisher: Springer Science and Business Media LLC
Date: 06-2023
DOI: 10.1007/S11207-023-02170-1
Abstract: The middle corona, the region roughly spanning heliocentric distances from 1.5 to 6 solar radii, encompasses almost all of the influential physical transitions and processes that govern the behavior of coronal outflow into the heliosphere. The solar wind, eruptions, and flows pass through the region, and they are shaped by it. Importantly, the region also modulates inflow from above that can drive dynamic changes at lower heights in the inner corona. Consequently, the middle corona is essential for comprehensively connecting the corona to the heliosphere and for developing corresponding global models. Nonetheless, because it is challenging to observe, the region has been poorly studied by both major solar remote-sensing and in-situ missions and instruments, extending back to the Solar and Heliospheric Observatory (SOHO) era. Thanks to recent advances in instrumentation, observational processing techniques, and a realization of the importance of the region, interest in the middle corona has increased. Although the region cannot be intrinsically separated from other regions of the solar atmosphere, there has emerged a need to define the region in terms of its location and extension in the solar atmosphere, its composition, the physical transitions that it covers, and the underlying physics believed to shape the region. This article aims to define the middle corona, its physical characteristics, and give an overview of the processes that occur there.
Publisher: American Astronomical Society
Date: 31-07-2023
Publisher: American Astronomical Society
Date: 10-02-2020
Abstract: The goal of the SunPy project is to facilitate and promote the use and development of community-led, free, and open source data analysis software for solar physics based on the scientific Python environment. The project achieves this goal by developing and maintaining the sunpy core package and supporting an ecosystem of affiliated packages. This paper describes the first official stable release (version 1.0) of the core package, as well as the project organization and infrastructure. This paper concludes with a discussion of the future of the SunPy project.
Publisher: American Geophysical Union (AGU)
Date: 07-2016
DOI: 10.1002/2016JC011858
Publisher: Elsevier BV
Date: 11-2011
Publisher: Springer Science and Business Media LLC
Date: 24-02-2013
DOI: 10.1038/NGEO1738
Publisher: Springer Science and Business Media LLC
Date: 04-2020
DOI: 10.1007/S11207-020-01622-2
Abstract: The SunPy Project developed a 13-question survey to understand the software and hardware usage of the solar-physics community. Of the solar-physics community, 364 members across 35 countries responded to our survey. We found that $99\\pm 0.5$ 99 ± 0.5 % of respondents use software in their research and 66% use the Python scientific-software stack. Students are twice as likely as faculty, staff scientists, and researchers to use Python rather than Interactive Data Language (IDL). In this respect, the astrophysics and solar-physics communities differ widely: 78% of solar-physics faculty, staff scientists, and researchers in our s le uses IDL, compared with 44% of astrophysics faculty and scientists s led by Momcheva and Tollerud (2015). $63\\pm 4$ 63 ± 4 % of respondents have not taken any computer-science courses at an undergraduate or graduate level. We also found that most respondents use consumer hardware to run software for solar-physics research. Although 82% of respondents work with data from space-based or ground-based missions, some of which ( e.g. the Solar Dynamics Observatory and Daniel K. Inouye Solar Telescope ) produce terabytes of data a day, 14% use a regional or national cluster, 5% use a commercial cloud provider, and 29% use exclusively a laptop or desktop. Finally, we found that $73\\pm 4$ 73 ± 4 % of respondents cite scientific software in their research, although only $42\\pm 3$ 42 ± 3 % do so routinely.
Publisher: American Society for Pharmacology & Experimental Therapeutics (ASPET)
Date: 08-11-2019
Abstract: Dynamin-related protein-1 (DRP-1)-dependent mitochondrial fission may influence cardiac tolerance to ischemic or oxidative stress, presenting a potential "cardioprotective" target. Effects of dynamin inhibitors [mitochondrial ision inhibitor 1 (MDIVI-1) and dynasore] on injury, mitochondrial function, and signaling proteins were assessed in distinct models: ischemia-reperfusion (I-R) in mouse hearts and oxidative stress in rat H9c2 cardiomyoblasts. Hearts exhibited substantial cell death [approx. 40 IU lactate dehydrogenase (LDH) efflux] and dysfunction (approx. 40 mmHg diastolic pressure, approx. 40% contractile recovery) following 25 minutes' ischemia. Pretreatment with 1
Publisher: American Astronomical Society
Date: 07-2022
Abstract: The outer atmosphere of the Sun is composed of plasma heated to temperatures well in excess of the visible surface. We investigate short cool and warm ( MK) loops seen in the core of an active region to address the role of field-line braiding in energizing these structures. We report observations from the High-resolution Coronal imager (Hi-C) that have been acquired in a coordinated c aign with the Interface Region Imaging Spectrograph (IRIS). In the core of the active region, the 172 Å band of Hi-C and the 1400 Å channel of IRIS show plasma loops at different temperatures that run in parallel. There is a small but detectable spatial offset of less than 1″ between the loops seen in the two bands. Most importantly, we do not see observational signatures that these loops might be twisted around each other. Considering the scenario of magnetic braiding, our observations of parallel loops imply that the stresses put into the magnetic field have to relax while the braiding is applied: the magnetic field never reaches a highly braided state on these length scales comparable to the separation of the loops. This supports recent numerical 3D models of loop braiding in which the effective dissipation is sufficiently large that it keeps the magnetic field from getting highly twisted within a loop.
Publisher: Springer Science and Business Media LLC
Date: 08-2022
Publisher: Springer Science and Business Media LLC
Date: 23-08-2016
DOI: 10.1038/NCOMMS12577
Abstract: A fourth production region for the globally important Antarctic bottom water has been attributed to dense shelf water formation in the Cape Darnley Polynya, adjoining Prydz Bay in East Antarctica. Here we show new observations from CTD-instrumented elephant seals in 2011–2013 that provide the first complete assessment of dense shelf water formation in Prydz Bay. After a complex evolution involving opposing contributions from three polynyas (positive) and two ice shelves (negative), dense shelf water (salinity 34.65–34.7) is exported through Prydz Channel. This provides a distinct, relatively fresh contribution to Cape Darnley bottom water. Elsewhere, dense water formation is hindered by the freshwater input from the Amery and West Ice Shelves into the Prydz Bay Gyre. This study highlights the susceptibility of Antarctic bottom water to increased freshwater input from the enhanced melting of ice shelves, and ultimately the potential collapse of Antarctic bottom water formation in a warming climate.
Publisher: International Glaciological Society
Date: 2014
Abstract: Oceanographic instruments suspended beneath the Amery Ice Shelf, East Antarctica, have recorded sporadic pressure decreases of 10–20 dbar over a few days at three sites where basal marine ice growth is expected. We attribute these events to flotation due to platelet ice accretion on the instrument moorings. Some events were transient, rapidly returning to pre-event pressures, probably through dislodgement of loosely attached crystals. Driven by these pressure changes, temperatures recorded by the shallowest instruments (within 20 m of the shelf base) tracked in situ freezing temperatures during the events. These observations provide indirect evidence for the presence of frazil ice in the sub-ice-shelf mixed layer and for active marine ice accretion. At one site we infer that a dense layer of platelet ice ˜1.5 m thick was accreted to the ice shelf over a 50 day period. Following some permanent abrupt pressure decreases (which we interpret as due to the lodgement of the uppermost instrument at the ice-shelf base), altered background trends in pressure suggest compaction rates of 3–4 m a –1 for the accreted basal platelet layer. Attachment of platelet ice and resulting displacement of moorings has ramifications for project design and instrument deployment, and implications for interpretation of oceanographic data from sub-ice-shelf environments.
Publisher: American Geophysical Union (AGU)
Date: 2010
DOI: 10.1029/2010EO450006
Publisher: Springer Science and Business Media LLC
Date: 11-11-2011
Publisher: The Oceanography Society
Date: 12-2016
Publisher: American Astronomical Society
Date: 31-07-2023
Publisher: Frontiers Media SA
Date: 08-08-2019
Publisher: American Geophysical Union (AGU)
Date: 12-2013
DOI: 10.1002/2013JC009158
Location: Australia
Start Date: 12-2022
End Date: 12-2025
Amount: $672,000.00
Funder: Australian Research Council
View Funded Activity