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EOS, TRANSACTIONS AMERICAN GEOPHYSICAL UNION, VOL. 86, NO. 36, doi:10.1029/2005EO360003, 2005

Reductions in Arctic Sea Ice Cover No Longer Limited to Summer

Walter Meier

National Snow and Ice Data Center, Cooperative Institute for Research in the Environmenal Sciences, University of Colorado, Boulder, Colorado, USA


Julienne Stroeve

National Snow and Ice Data Center, Cooperative Institute for Research in the Environmenal Sciences, University of Colorado, Boulder, Colorado, USA


Florence Fetterer

National Snow and Ice Data Center, Cooperative Institute for Research in the Environmenal Sciences, University of Colorado, Boulder, Colorado, USA


Ken Knowles

National Snow and Ice Data Center, Cooperative Institute for Research in the Environmenal Sciences, University of Colorado, Boulder, Colorado, USA


Abstract

Summer sea ice in the Arctic has shown a significant downward trend of 8% per decade since the late 1970s, leading to a reduction of approximately 20% in sea ice extent in September (when the annual minimum occurs) [Stroeve et al., 2005]. The past three summers (2002―2004( have been among the lowest on record, and 2002 was the extreme minimum. Despite decreasing summer extents, the sea ice extent has typically rebounded to near-normal levels during the winter season, yielding an annual average trend of only -3%percnt;. This is not surprising since as temperatures drop below freezing, sea ice quickly forms. However, this may be changing. All months of the winter and spring of 2004―2005 (December―May( were well below normal, and every month except May 2005 had record low extents (Figure 1). Now the wintertime trend alone is approaching -3% per decade. Also unusual is the fact that the reduction occurred in all regions of the Arctic, on both the Atlantic and Pacific sides (Figure 2). In the past, while one area of the Arctic may be anomalously low, another region will be higher than normal. This may be an indication that the reduced summer sea ice extents are allowing more heat to be absorbed by the ocean and delaying the onset of freeze-up throughout the Arctic.

Published 6 September 2005.

Index Terms: 0750 Cryosphere: Sea ice (4540); 1621 Global Change: Cryospheric change (0776); 0758 Cryosphere: Remote sensing.

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Citation: Meier, W., J. Stroeve, F. Fetterer, and K. Knowles (2005), Reductions in Arctic Sea Ice Cover No Longer Limited to Summer, Eos Trans. AGU, 86(36), doi:10.1029/2005EO360003.