Articles | Volume 33, issue 3
https://doi.org/10.5194/npg-33-455-2026
© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/npg-33-455-2026
© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Covariations between persistent synoptic features and record low Antarctic sea ice events via unsupervised regression learning
Andrew R. Axelsen
CORRESPONDING AUTHOR
School of Natural Sciences, University of Tasmania, Hobart, 7001, Tasmania, Australia
CSIRO Environment, Battery Point, 7004, Tasmania, Australia
Terence J. O'Kane
CSIRO Environment, Battery Point, 7004, Tasmania, Australia
School of Natural Sciences, University of Tasmania, Hobart, 7001, Tasmania, Australia
Courtney R. Quinn
School of Natural Sciences, University of Tasmania, Hobart, 7001, Tasmania, Australia
Andrew P. Bassom
School of Natural Sciences, University of Tasmania, Hobart, 7001, Tasmania, Australia
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Geosci. Model Dev., 19, 3853–3873, https://doi.org/10.5194/gmd-19-3853-2026, https://doi.org/10.5194/gmd-19-3853-2026, 2026
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Recent advancements in regional ocean modelling allow higher resolution simulations providing improved estimates of the large-scale ocean state, while also revealing new insights into the fine-scale processes connecting the open ocean to the continental shelf seas. Our study highlights the importance of increased model resolution in regions of the ocean that are particularly turbulent while in quasi-stable circulation regions (e.g., jets), the current state-of-the-art global models do suffice.
Mark A. Collier, Dylan Harries, and Terence J. O'Kane
Nonlin. Processes Geophys., 33, 103–122, https://doi.org/10.5194/npg-33-103-2026, https://doi.org/10.5194/npg-33-103-2026, 2026
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Here we apply Bayesian methods to reconstructed and simulated climate model data over past decades to determine the role of long timescale phase dependencies, and extratropical teleconnections, on the major drivers of tropical climate variability.
Terence J. O'Kane and Courtney R. Quinn
Nonlin. Processes Geophys., 33, 51–72, https://doi.org/10.5194/npg-33-51-2026, https://doi.org/10.5194/npg-33-51-2026, 2026
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Mathematical concepts and measures from dynamical systems theory are applied to identify commonalities across a diverse set of chaotic attractors to better understand the relationship between predictability, directions and rates of expansion and contraction of instabilities over finite time forecast horizons, and dimensionality. The patterns that emerge have broad implications for understanding many dynamical features of geophysical flows.
Samuel Watson and Courtney Quinn
Nonlin. Processes Geophys., 31, 381–394, https://doi.org/10.5194/npg-31-381-2024, https://doi.org/10.5194/npg-31-381-2024, 2024
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The intensification of tropical cyclones (TCs) is explored through a conceptual model derived from geophysical principals. Focus is put on the behaviour of the model with parameters which change in time. The rates of change cause the model to either tip to an alternative stable state or recover the original state. This represents intensification, dissipation, or eyewall replacement cycles (ERCs). A case study which emulates the rapid intensification events of Hurricane Irma (2017) is explored.
Serena Schroeter, Terence J. O'Kane, and Paul A. Sandery
The Cryosphere, 17, 701–717, https://doi.org/10.5194/tc-17-701-2023, https://doi.org/10.5194/tc-17-701-2023, 2023
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Antarctic sea ice has increased over much of the satellite record, but we show that the early, strongly opposing regional trends diminish and reverse over time, leading to overall negative trends in recent decades. The dominant pattern of atmospheric flow has changed from strongly east–west to more wave-like with enhanced north–south winds. Sea surface temperatures have also changed from circumpolar cooling to regional warming, suggesting recent record low sea ice will not rapidly recover.
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Short summary
Recent increases in the variability of Antarctic sea ice have elicited much interest and research on these changes. Here, we examine observations taken from three specific years (2016, 2021, and 2023) which either contain or precede a period of anomalously low sea ice extent. To understand the combined influence of weather systems, surface temperatures, and atmospheric pressure on sea ice formation and decay, we apply novel methods from machine learning and dynamical systems.
Recent increases in the variability of Antarctic sea ice have elicited much interest and...