The Decrease of the Arctic Sea Ice and the Abrupt Changes of Sea Ice in 1990s

Based on the Hadlley Centre Arctic sea-ice data for the period 1968~2000,it is found that the decrease tendency of the Arctic sea-ice in the North Hemisphere is very obvious.Since 1968,the sea-ice extent decrease was appeared in the Barents Sea,Greenland Sea and Bering Sea during winter,and the kola Sea and East Siberia Sea during summer.During 1990s the decrease was suddenly appeared in all areas of the Arctic Ocean,i.e.abrupt change,especially in the Barents Sea and Greenland Sea.The sea ice change over the Arctic Ocean is larger than the normal nature variation.The sea-ice seasonal patterns have the seasonal persistence and high relationship with the pattern before 1~4 seasons.Therefore the Sea-ice decrease tendency should maintain long time during the recent period.