Modeling the Impacts of Antarctic Sea Ice Decline: Responses of Atmospheric Dynamics

Abstract

Rapidly changing climate in polar regions not only impacts their local environments but also influences weather patterns in tropical and mid-latitude regions. A key indicator of these changes is the accelerated decline of sea ice in polar areas. In this study, we investigated the atmospheric impacts of Antarctic sea ice reduction in response to intensified ocean surface winds. We employed the Polar-WRF model, driven by ERA5 initial and boundary conditions between 2005 and 2011. The sea ice concentration (SIC) and sea surface temperature (SST) conditions were derived from two realistic regional Southern Ocean MITgcm simulations, consisting of a control and a wind sensitivity experiment. In the latter, the zonal wind stress over the Southern Ocean is increased by a factor of 1.5, leading to a significant decrease in SIC and an increase in SST. Our Polar-WRF simulations indicate that the winter and spring seasons are marked by significant meteorological changes, including a notable increase in surface air temperature (over 2.4°C) and sea level pressure (over 2 hPa). These atmospheric changes are particularly large in the Bellingshausen Sea, adjacent to the Antarctic Peninsula and the Western Pacific Ocean. The intensified advection of warm-moist air may further contribute to sea ice decline, with potential implications for increased melting of ice shelves in the Weddell and Ross Seas. The simulations illustrate that variations in wind stress could provide insights into the atmospheric-sea ice dynamics driving recent record lows in Antarctic sea ice, underscoring the importance of such modeling for understanding and predicting changes.