The Responses of Antarctic Sea Ice and Overturning Cells to Meridional Wind Forcing
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clim-JCLI-D-24-0070.1 (1).pdf
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Author(s)
Song, Hajoon
Choi, Yeonju
Doddridge, Edward W
Marshall, John
Date Issued
January 10, 2025
Journal
Journal of Climate
Publisher
American Meteorological Society
Citation
Song, H., Y. Choi, E. W. Doddridge, and J. Marshall, 2025: The Responses of Antarctic Sea Ice and Overturning Cells to Meridional Wind Forcing. J. Climate, 38, 701–716.
Version
Final published version
Abstract
Meridional winds over the seasonal ice zone of the Antarctic have undergone changes and likely contributed to sea ice extent variability in recent decades. In this study, using observations and an eddy-resolving channel model of the Antarctic seasonal ice zone, we investigate the influence of meridional wind changes on the sea ice distribution and document how the underlying ocean might change. We find that southerly wind anomalies in austral winter lead to an increase in sea ice extent by encouraging equatorward sea ice drift. This results in more leads and polynyas, ice production, and buoyancy loss near the coastal region and freshening out in the open ocean near the Antarctic Circumpolar Current. In contrast, summertime southerly wind anomalies reduce sea ice extent due to warming anomalies near the sea ice edge. This is a consequence of enhanced meridional overturning circulation (MOC) triggered by enhanced buoyancy loss through surface heat flux and brine rejection, which brings relatively warm water toward the summertime sea ice edge. A water-mass transformation analysis reveals the increased bottom water formation caused by brine rejection and heat loss in leads and polynyas. Changes in sea ice extent and MOC behave in the opposite way when the sign of the wind anomaly is switched from southerly to northerly. Our study shows that meridional wind anomalies can modify not only the sea ice distribution, extent of polynyas, and air–sea buoyancy fluxes but also the ocean’s MOC and bottom water properties.
Subjects
Sea ice
Southern Ocean
Meridional overturning circulation
Idealized models
Ocean models
Terms of Use
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
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DOI of Published Version
https://doi.org/10.1175/JCLI-D-24-0070.1
