Non-annular atmospheric circulation change induced by stratospheric ozone depletion and its role in the recent increase of Antarctic sea ice extent

Based on a new analysis of passive microwave satellite data, we demonstrate that the annual mean extent of Antarctic sea ice has increased at a statistically significant rate of 0.97% dec−1 since the late 1970s. The largest increase has been in autumn when there has been a dipole of significant positive and negative trends in the Ross and Amundsen‐Bellingshausen Seas respectively. The autumn increase in the Ross Sea sector is primarily a result of stronger cyclonic atmospheric flow over the Amundsen Sea. Model experiments suggest that the trend towards stronger cyclonic circulation is mainly a result of stratospheric ozone depletion, which has strengthened autumn wind speeds around the continent, deepening the Amundsen Sea Low through flow separation around the high coastal orography. However, statistics derived from a climate model control run suggest that the observed sea ice increase might still be within the range of natural climate variability.


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Authors: Turner, John ORCIDORCID record for John Turner, Comiso, Josefino C., Marshall, Gareth J. ORCIDORCID record for Gareth J. Marshall, Lachlan-Cope, Tom A. ORCIDORCID record for Tom A. Lachlan-Cope, Bracegirdle, Tom ORCIDORCID record for Tom Bracegirdle, Maksym, Ted, Meredith, Michael P. ORCIDORCID record for Michael P. Meredith, Wang, Zhaomin ORCIDORCID record for Zhaomin Wang, Orr, Andrew ORCIDORCID record for Andrew Orr

On this site: Andrew Orr, Gareth Marshall, John Turner, Michael Meredith, Thomas Bracegirdle, Thomas Lachlan-Cope, Zhaomin Wang
23 April, 2009
Geophysical Research Letters / 36
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