3月北半球海冰趋势变化的区域特征及影响因子分析

利用海冰密集度资料和海冰范围指数,分析了3月北半球海冰在1979-1995年和1996-2014年2个时间段内的变化趋势以及趋势差异的区域特征.结果表明:北半球3月总海冰范围以稳定速率减少,速率无明显加速.而各个分海域的海冰变化表现出一定的区域差异.其中,巴伦支海海冰在2个时期内以稳定的速率减少;白令海海冰不减反增;鄂霍次克海海冰缩减速度在后期减小;圣劳伦斯湾的海冰范围在90年代中期以前显著增大,后期缓慢缩减. 3月海冰趋势变化的空间特征与同期表面气温和表面风场的趋势变化相一致.

Regional Features and Factors of the Northern Hemisphere Sea Ice Trends in March

Based on the data of sea ice concentration and using the sea ice extent (SIE) index, the present study investigates the changes in the Northern Hemisphere sea ice trends in March during 1979-1995 and 1996-2014 and their regional features. The results show that although the negative slope of March SIE over the whole Northern Hemisphere did not experience obvious changes with time, pronounced regional differences were present in the sea ice trend and its change in the mid-1990s. The Barents Sea SIE exhibited a significant downward trend in both periods with a relatively steady rate. The SIE in the Bering Sea showed a positive trend and the slope became steeper after the late 1990s. The Sea of Okhotsk was subjected to ice loss during both periods with a notable increase in between. The SIE in the Gulf of St. Lawrence showed an upward trend during the earlier period and was dominated by inter-annual fluctuations during the later period. The trends and their changes in the mid-1990s of the March sea ice were consistent with those in surface air temperature and atmospheric wind.