Apr 23, 2009

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

Turner, John, Comiso, Josefino C., Marshall, Gareth J., Lachlan‐Cope, Tom A., Bracegirdle, Tom, Maksym, Ted, Meredith, Michael P., Wang, Zhaomin, Orr, Andrew
Geophysical Research Letters
  • Demonstrates 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, based on a new analysis of passive microwave satellite data
  • Finds that 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
  • Finds that 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
  • Finds, however, that 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