Antarctic sea ice variability and trends, 1979–2010 Cryospheric Sciences Laboratory/Code 615, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
15 Aug 2012
Received: 14 Feb 2012 – Published in The Cryosphere Discuss.: 09 Mar 2012 Abstract. In sharp contrast to the decreasing sea ice coverage of the Arctic, in the
Antarctic the sea ice cover has, on average, expanded since the late 1970s.
More specifically, satellite passive-microwave data for the period November
1978–December 2010 reveal an overall positive trend in ice extents of
17 100 ± 2300 km2 yr−1. Much of the increase, at
13 700 ± 1500 km2 yr−1, has occurred in the region of
the Ross Sea, with lesser contributions from the Weddell Sea and Indian
Ocean. One region, that of the Bellingshausen/Amundsen Seas, has (like
the Arctic) instead experienced significant sea ice decreases, with an
overall ice extent trend of −8200 ± 1200 km2 yr−1. When
examined through the annual cycle over the 32-yr period 1979–2010, the
Southern Hemisphere sea ice cover as a whole experienced positive ice extent
trends in every month, ranging in magnitude from a low of
9100 ± 6300 km2 yr−1 in February to a high of
24 700 ± 10 000 km2 yr−1 in May. The Ross Sea and
Indian Ocean also had positive trends in each month, while the
Bellingshausen/Amundsen Seas had negative trends in each month, and
the Weddell Sea and western Pacific Ocean had a mixture of positive and
negative trends. Comparing ice-area results to ice-extent results, in each
case the ice-area trend has the same sign as the ice-extent trend, but the
magnitudes of the two trends differ, and in some cases these differences
allow inferences about the corresponding changes in sea ice concentrations.
The strong pattern of decreasing ice coverage in the
Bellingshausen/Amundsen Seas region and increasing ice coverage in the
Ross Sea region is suggestive of changes in atmospheric circulation. This is
a key topic for future research.
Revised: 16 May 2012 – Accepted: 01 Jun 2012 – Published: 15 Aug 2012
Citation: Parkinson, C. L. and Cavalieri, D. J.: Antarctic sea ice variability and trends, 1979–2010, The Cryosphere, 6, 871-880, doi:10.5194/tc-6-871-2012, 2012.