CHANGES IN ARCTIC SEA ICE EXTENT IN THE 20TH CENTURY

V. F. Zakharov

Observations of Arctic sea ice throughout the 20th century reveal substantial interannual and long-term changes in ice extent. The character of these changes allows us to single out four intrasecular stages in the development of sea ice: two stages of ice growth (1900—1918 and 1938—1968) and two stages of ice decrease (1918—1938 and 1968—1996) manifested against the background of the secular sea ice reduction. The linear trend for growth stages was 169,000 and 122,000 km2 per 10 years, respectively, while for the ice decrease periods it was —200,000 and —122,000 km2 per 10 years. As a whole for the 1900—1996 period this parameter is —56,000 km2 per 10 years.