ORCID Profile
0000-0002-8590-8645
Current Organisations
CSIRO
,
University of Tasmania
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Publisher: Elsevier BV
Date: 11-2019
Publisher: American Geophysical Union (AGU)
Date: 17-03-2022
DOI: 10.1029/2021GL097002
Abstract: Marine cold‐spell (MCS) metrics—such as frequency and intensity—are decreasing globally, while marine heatwave (MHW) metrics are increasing due to sea surface temperature (SST) warming. However, the concomitant changes in MHW and MCS metrics, and whether SST warming can similarly explain the decreasing MCS metrics remain unclear. Here, we provide a comparative global assessment of these changes based on satellite SST observations over 1982–2020. Across the globe, we find distinct differences in mean MHW and MCS metrics. Furthermore, decreasing trends in MCS metrics are not necessarily aligned with increasing trends in MHW metrics. While differences in intensity trends are mainly explained by SST variance trends, differences in trends of annual days are less clear. Overall, decreasing MCS days and intensities are found to be largely driven by warming SST, rather than SST variance changes. Therefore, it is expected that MCS days and intensity will continue diminishing under global warming.
Publisher: Elsevier BV
Date: 11-2018
Publisher: American Geophysical Union (AGU)
Date: 12-2015
DOI: 10.1002/2015JC011026
Publisher: Copernicus GmbH
Date: 12-08-2015
Abstract: Abstract. Oceanic eddies exist throughout the world oceans, but are more energetic when associated with western boundary currents (WBC) systems. In these regions, eddies play an important role in mixing and energy exchange. Therefore, it is important to quantify and qualify eddies associated with these systems. This is particularly true for the Southern Hemisphere WBC system where only few eddy censuses have been performed to date. In these systems, important aspects of the local eddy population are still unknown, like their spatial distribution and propagation patterns. Moreover, the understanding of these patterns helps to establish monitoring programs and to gain insight in how eddies would affect local mixing. Here, we use a global eddy data set to qualify eddies based on their surface characteristics in the Agulhas Current (AC), the Brazil Current (BC) and the East Australian Current (EAC) systems. The analyses reveal that eddy propagation within each system is highly forced by the local mean flow and bathymetry. Large values of eddy litude and temporal variability are associated with the BC and EAC retroflections, while small values occur in the centre of the Argentine Basin and in the Tasman Sea. In the AC system, eddy polarity dictates the propagation distance. BC system eddies do not propagate beyond the Argentine Basin, and are advected by the local ocean circulation. EAC system eddies from both polarities cross south of Tasmania but only the anticyclonic ones reach the Great Australian Bight. For all three WBC systems, both cyclonic and anticyclonic eddies present a geographical segregation according to radius size and litude. Regions of high eddy kinetic energy are associated with the eddies' mean litudes, and not with their densities.
Publisher: Copernicus GmbH
Date: 05-02-2020
Abstract: Abstract. We introduce ACCESS-OM2, a new version of the ocean–sea ice model of the Australian Community Climate and Earth System Simulator. ACCESS-OM2 is driven by a prescribed atmosphere (JRA55-do) but has been designed to form the ocean–sea ice component of the fully coupled (atmosphere–land–ocean–sea ice) ACCESS-CM2 model. Importantly, the model is available at three different horizontal resolutions: a coarse resolution (nominally 1∘ horizontal grid spacing), an eddy-permitting resolution (nominally 0.25∘), and an eddy-rich resolution (0.1∘ with 75 vertical levels) the eddy-rich model is designed to be incorporated into the Bluelink operational ocean prediction and reanalysis system. The different resolutions have been developed simultaneously, both to allow for testing at lower resolutions and to permit comparison across resolutions. In this paper, the model is introduced and the in idual components are documented. The model performance is evaluated across the three different resolutions, highlighting the relative advantages and disadvantages of running ocean–sea ice models at higher resolution. We find that higher resolution is an advantage in resolving flow through small straits, the structure of western boundary currents, and the abyssal overturning cell but that there is scope for improvements in sub-grid-scale parameterizations at the highest resolution.
Publisher: American Geophysical Union (AGU)
Date: 07-2022
DOI: 10.1029/2022EA002312
Abstract: Since the Argo program began, 568 floats returned almost 31,000 profiles, at high‐southern latitudes, with no measured position. These data are either disseminated with positions linearly interpolated between known positions, or with no geographic positions. Here, we present a simple method for estimating unknown Argo float trajectories. We try to identify trajectories that approximately follow contours along three different properties: potential vorticity ( f / H ), sea‐level, and density at 1,000 m. No single property‐constraint can be used to estimate trajectories for all position‐gaps. Each constraint fails for 9%–18% of gaps, where no continuous contour between the end‐points exists. But all constraints fail for the same position‐gap, for fewer than 1% of cases. For a given position‐gap, when a trajectory is identified using two or three different constraints, we select the shortest trajectory to be used to “fill the gap”. This selection process could be performed better by an Expert Operator, inspecting each estimated trajectory, and selecting the trajectory that is most consistent with a priori knowledge of the circulation in the vicinity of the position‐gap. Nonetheless, using the objective metric for selection, we find that 41.2% of position‐gaps use the f / H ‐constraint, 32.1% use density, and 25.8% use sea‐level. We assess the estimated trajectories for consistency, by comparing bottom depths beneath trajectories to the deepest measurements in each profile. We find inconsistencies for 11.6% of position‐gaps using our method, compared to 28.0% using linearly‐interpolated trajectories. Adoption of the estimated trajectories for measurements under ice may yield benefits to many applications.
Publisher: American Geophysical Union (AGU)
Date: 08-2022
DOI: 10.1029/2022JC018931
Abstract: During the austral summer of 2017/2018, the Tasman Sea experienced an intense marine heatwave over an extensive area. It persisted for approximately 3 months and caused substantial ecological impacts. The marine heatwave was understood to have been driven primarily by increased net downward heat flux associated with a high pressure system. However, it has been unclear why the marine heatwave persisted. Using an ultra‐high‐resolution (∼1 km) regional ocean model simulation, the drivers, dynamics, and persistence of the 2017/2018 marine heatwave are explored in detail. It is found that a burst of warm water advection helped to initiate the event, but a shallower than usual mixed layer, coupled with near continuous net downward air‐sea heat flux, caused the marine heatwave to persist. Submesoscale dynamics were found to be relatively unimportant to the marine heatwave's persistence.
Publisher: American Geophysical Union (AGU)
Date: 26-12-2019
DOI: 10.1029/2019GL084928
Publisher: Elsevier BV
Date: 09-2019
Publisher: Elsevier BV
Date: 10-2008
DOI: 10.1016/J.SCHRES.2008.06.021
Abstract: An increased prevalence of large cavum septum pellucidum (CSP), a marker of midline neurodevelopmental abnormality, has been reported in schizophrenia. However, not all studies have been able to replicate this finding and very few studies have been conducted in large s les. In the current study, magnetic resonance imaging was used to assess the presence of an abnormal CSP in 162 patients with first-episode psychosis (FEP), 89 patients with chronic schizophrenia, 135 ultra high-risk (UHR) in iduals, and 87 controls. The prevalence of a large CSP (>5.6 mm) did not differ between the groups (9.3% of the FEP patients, 11.2% of the chronic schizophrenia patients, 11.1% of the UHR in iduals, and 11.5% of the controls). The length of the CSP was not associated with sulcal morphology of the anterior cingulate cortex (ACC), suggesting different biological processes responsible for the CSP enlargement versus ACC folding. These findings suggest that the CSP is not a neurodevelopmental marker of psychosis and cast doubt over the notion that it plays a major role in the neurobiology of psychosis.
Publisher: Wiley
Date: 17-11-2021
Publisher: American Geophysical Union (AGU)
Date: 03-2018
DOI: 10.1002/2017JC013298
Location: Australia
No related grants have been discovered for Gabriela Pilo.