May 27, 2024: Ocean Circulation and Climate Dynamics Colloquium

Dr. Hannah Dawson, University of New South Wales, Sydney, Australia: "End-of-21st century changes to Antarctic margin circulation and hydrography under different emissions scenarios"

When?  Monday, 27 May 2024 at 11 am
Where?    Lecture Hall, Building 8A, Wischofstr. 1-3 and 

The Antarctic margins play a crucial role in our global climate system, yet possible end-of-21st century changes to ocean circulation and hydrography under different climate scenarios remain poorly constrained. This is because many climate models fail to adequately resolve key features of the Antarctic margin including the narrow westward flowing currents, and the formation of both dense and  abyssal water masses. Studies conducted with models that do resolve many of these features often focus on high emissions scenarios at the middle of this century. In this study we force a 0.1°  global ocean-sea ice model with spatially variable climate anomalies derived from CMIP6 models to investigate the impact of mid- (SSP2-4.5) and high-range (SSP5-8.5) emissions on Antarctic margin circulation at the end of this century. We run these simulations with and without future freshwater contributions from the Antarctic Ice Sheet to assess changes in the presence and absence of meltwater, which still represents a large source of uncertainty in climate projections. We focus on changes under the mid-range emissions scenario and show that, even without additional meltwater forcing, substantial changes in Antarctic continental shelf circulation and hydrography are anticipated by the end of this century. Our results also suggest that the temperature response around the Antarctic margins is sensitive to the magnitude of future freshwater forcing, highlighting a need for better constraints on projections of meltwater contributions from the Antarctic Ice Sheet under different climate scenarios.

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