Variability of Antarctic Sea Ice 1979-1998
The principal characteristics of the variability of Antarctic sea ice cover as previously described from satellite passive-microwave observations are also evident in a systematically-calibrated and analyzed data set for 20.2 years (1979-1998). The total Antarctic sea ice extent (concentration > 1...
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ftnasantrs:oai:casi.ntrs.nasa.gov:20010100393 2023-05-15T14:03:46+02:00 Variability of Antarctic Sea Ice 1979-1998 Comiso, Josefino C. Cavalieri, Donald J. Gloersen, Per Koblinsky, Chester J. Parkinson, Claire L. Zwally, H. Jay Unclassified, Unlimited, Publicly available [2001] application/pdf http://hdl.handle.net/2060/20010100393 unknown Document ID: 20010100393 http://hdl.handle.net/2060/20010100393 No Copyright CASI Oceanography 2001 ftnasantrs 2015-03-15T02:28:12Z The principal characteristics of the variability of Antarctic sea ice cover as previously described from satellite passive-microwave observations are also evident in a systematically-calibrated and analyzed data set for 20.2 years (1979-1998). The total Antarctic sea ice extent (concentration > 15 %) increased by 13,440 +/- 4180 sq km/year (+1.18 +/- 0.37%/decade). The area of sea ice within the extent boundary increased by 16,960 +/- 3,840 sq km/year (+1.96 +/- 0.44%/decade). Regionally, the trends in extent are positive in the Weddell Sea (1.5 +/- 0.9%/decade), Pacific Ocean (2.4 +/- 1.4%/decade), and Ross (6.9 +/- 1.1 %/decade) sectors, slightly negative in the Indian Ocean (-1.5 +/- 1.8%/decade, and strongly negative in the Bellingshausen-Amundsen Seas sector (-9.5 +/- 1.5%/decade). For the entire ice pack, small ice increases occur in all seasons with the largest increase during autumn. On a regional basis, the trends differ season to season. During summer and fall, the trends are positive or near zero in all sectors except the Bellingshausen-Amundsen Seas sector. During winter and spring, the trends are negative or near zero in all sectors except the Ross Sea, which has positive trends in all seasons. Components of interannual variability with periods of about 3 to 5 years are regionally large, but tend to counterbalance each other in the total ice pack. The interannual variability of the annual mean sea-ice extent is only 1.6% overall, compared to 5% to 9% in each of five regional sectors. Analysis of the relation between regional sea ice extents and spatially-averaged surface temperatures over the ice pack gives an overall sensitivity between winter ice cover and temperature of -0.7% change in sea ice extent per K. For summer, some regional ice extents vary positively with temperature and others negatively. The observed increase in Antarctic sea ice cover is counter to the observed decreases in the Arctic. It is also qualitatively consistent with the counterintuitive prediction of a global atmospheric-ocean model of increasing sea ice around Antarctica with climate warming due to the stabilizing effects of increased snowfall on the Southern Ocean. Other/Unknown Material Antarc* Antarctic Antarctica Arctic ice pack Ross Sea Sea ice Southern Ocean Weddell Sea NASA Technical Reports Server (NTRS) Antarctic Arctic Indian Pacific Ross Sea Southern Ocean Weddell Weddell Sea |
institution |
Open Polar |
collection |
NASA Technical Reports Server (NTRS) |
op_collection_id |
ftnasantrs |
language |
unknown |
topic |
Oceanography |
spellingShingle |
Oceanography Comiso, Josefino C. Cavalieri, Donald J. Gloersen, Per Koblinsky, Chester J. Parkinson, Claire L. Zwally, H. Jay Variability of Antarctic Sea Ice 1979-1998 |
topic_facet |
Oceanography |
description |
The principal characteristics of the variability of Antarctic sea ice cover as previously described from satellite passive-microwave observations are also evident in a systematically-calibrated and analyzed data set for 20.2 years (1979-1998). The total Antarctic sea ice extent (concentration > 15 %) increased by 13,440 +/- 4180 sq km/year (+1.18 +/- 0.37%/decade). The area of sea ice within the extent boundary increased by 16,960 +/- 3,840 sq km/year (+1.96 +/- 0.44%/decade). Regionally, the trends in extent are positive in the Weddell Sea (1.5 +/- 0.9%/decade), Pacific Ocean (2.4 +/- 1.4%/decade), and Ross (6.9 +/- 1.1 %/decade) sectors, slightly negative in the Indian Ocean (-1.5 +/- 1.8%/decade, and strongly negative in the Bellingshausen-Amundsen Seas sector (-9.5 +/- 1.5%/decade). For the entire ice pack, small ice increases occur in all seasons with the largest increase during autumn. On a regional basis, the trends differ season to season. During summer and fall, the trends are positive or near zero in all sectors except the Bellingshausen-Amundsen Seas sector. During winter and spring, the trends are negative or near zero in all sectors except the Ross Sea, which has positive trends in all seasons. Components of interannual variability with periods of about 3 to 5 years are regionally large, but tend to counterbalance each other in the total ice pack. The interannual variability of the annual mean sea-ice extent is only 1.6% overall, compared to 5% to 9% in each of five regional sectors. Analysis of the relation between regional sea ice extents and spatially-averaged surface temperatures over the ice pack gives an overall sensitivity between winter ice cover and temperature of -0.7% change in sea ice extent per K. For summer, some regional ice extents vary positively with temperature and others negatively. The observed increase in Antarctic sea ice cover is counter to the observed decreases in the Arctic. It is also qualitatively consistent with the counterintuitive prediction of a global atmospheric-ocean model of increasing sea ice around Antarctica with climate warming due to the stabilizing effects of increased snowfall on the Southern Ocean. |
author |
Comiso, Josefino C. Cavalieri, Donald J. Gloersen, Per Koblinsky, Chester J. Parkinson, Claire L. Zwally, H. Jay |
author_facet |
Comiso, Josefino C. Cavalieri, Donald J. Gloersen, Per Koblinsky, Chester J. Parkinson, Claire L. Zwally, H. Jay |
author_sort |
Comiso, Josefino C. |
title |
Variability of Antarctic Sea Ice 1979-1998 |
title_short |
Variability of Antarctic Sea Ice 1979-1998 |
title_full |
Variability of Antarctic Sea Ice 1979-1998 |
title_fullStr |
Variability of Antarctic Sea Ice 1979-1998 |
title_full_unstemmed |
Variability of Antarctic Sea Ice 1979-1998 |
title_sort |
variability of antarctic sea ice 1979-1998 |
publishDate |
2001 |
url |
http://hdl.handle.net/2060/20010100393 |
op_coverage |
Unclassified, Unlimited, Publicly available |
geographic |
Antarctic Arctic Indian Pacific Ross Sea Southern Ocean Weddell Weddell Sea |
geographic_facet |
Antarctic Arctic Indian Pacific Ross Sea Southern Ocean Weddell Weddell Sea |
genre |
Antarc* Antarctic Antarctica Arctic ice pack Ross Sea Sea ice Southern Ocean Weddell Sea |
genre_facet |
Antarc* Antarctic Antarctica Arctic ice pack Ross Sea Sea ice Southern Ocean Weddell Sea |
op_source |
CASI |
op_relation |
Document ID: 20010100393 http://hdl.handle.net/2060/20010100393 |
op_rights |
No Copyright |
_version_ |
1766274617033359360 |