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A 21 year record of Arctic sea-ice extents and their regional, seasonal and monthly variability and trends

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Satellite passive-microwave data have been used to calculate sea-ice extents over the period 1979-99 for the north polar sea-ice cover as a whole and for each of nine regions. Over this 21 year time period, the trend in yearly-average ice extents for the ice cover as a whole is -32 900 ± 6100 km2 a-1 (-2.7 ± 0.5% per decade), indicating a statistically significant reduction in sea-ice coverage. Regionally, the reductions are greatest in the Arctic Ocean, the Kara and Barents Seas and the Seas of Okhotsk and Japan; and seasonally, the reductions are greatest in summer, for which season the 1979-99 trend in ice extents is -41 600 ± 12 900 km2 a-1 (-4.9 ± 1.5% per decade). On a monthly basis, the reductions are greatest in July and September for the north polar ice cover as a whole, in September for the Arctic Ocean, in June andJuly for the Kara and Barents Seas, and in April for the Seas of Okhotsk and Japan. Of the nine regions, only the Bering Sea and the Gulf of St Lawrence show positive ice-extent trends on a yearly-average basis. However, the increases in these two regions are not statistically significant. For the north polar region as a whole, and for the Arctic Ocean, the Seas of Okhotsk and Japan, and Hudson Bay, the negative trends in the yearly averages are statistically significant at a 99% confidence level.

Document Type: Research Article


Publication date: 2002-01-01

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  • The Annals of Glaciology is a peer-reviewed, thematic journal published 2 to 4 times a year by the International Glaciological Society (IGS). Publication frequency is determined and volume/issue numbers assigned by the IGS Council on a year-to-year basis and with a lead time of 3 to 4 years. The Annals of Glaciology is included in the ISI Science Citation Index from volume 50, number 50 onwards.

    Themes can be on any aspect of the study of snow and ice. Individual members can make a suggestion for a theme for an Annals issue to the Secretary General, who will forward it to the IGS Publications Committee. The IGS Publication Committee will make a recommendation for an individual themed Annals issue, together with a potential Annals Chief Editor for that issue, to IGS Council. The IGS Council will make the decision whether to proceed, taking into account the spread of topics and the overall capacity for publication of pages in Annals.

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