Change variation of the Antarctic sea ice and shelf ice

Sea ice data provided by Ice and Snow Center,USA and field observed sea ice data with assimilation processed are used to study the dynamic change and long-term change trend of the Antarctic sea ice.The study shows that,there was more ice period in the later stage of the 1970s,less ice period in the 1980s.While in the 1990s,the Antarctic sea ice was in raising trend,and more ice in later stage.Regional variation difference was very large with more ice in the eastern Antarctic,obviously less ice in the west Antarctic,both sides of the Antarctic Peninsula,especially in the Weddell Sea and the Bellingshausen Sea.The sea ice variation trend in the eastern and western Antarctic is always in opposite phase.In the later 1990s,sea ice in the Prydz Bay was obviously more.The outer periphery line of sea ice of the Antarctic Continent shelf,on the wholle,wasn't any evident retreat,it was in natural variation trend with collapse and also renascence.While in the western Antarctic,the Ronne ice shelf of the Weddell Sea and the eastern part of Ross Sea ice shelf,collapse and retreat trend was evident.The collapse and retreat of ice shelf in the eastern Antarctic also existed,but not as evident as in the western Antarctic.Iceberg transferred from shelf ice collapse to ocean gives a certain impact on global sea level raising.In a word,the Antarctic sea ice had not obviously decreased with global climate warming,but periodically changes,adjusts and restricts according to opposite phase variation rule in the eastern and western Antarctic.