【摘要】 白令海和楚科奇海位于北极太平洋一侧的海冰外缘线附近,具有较强烈的气冰海相互作用.采用滑动t检验和小波分析方法对白令海和楚科奇海1953—2004年海冰范围的年际变化、年代际变化和总体趋势变化进行分析.结果表明:20世纪70年代后期,海冰范围在白令海存在显著的均值突变现象,而楚科奇海在对应阶段则表现为更明显的变频现象;在突变点前后两个时段里,阿留申低压中心低压加强、核心位置偏移以及对应风场分布的变化是导致白令海海冰范围明显缩小的主要动力原因.楚科奇海海冰范围的年际变化中存在由低频向高频变化的现象,该现象除了在局地气温变化中存在之外,在北冰洋区域风涡度、波弗特海纬向风、东西伯利亚海经向风等动力因素中也有所体现.因此,除热力因素外,动力因素引起的海冰的平流与该变频现象也存在一定的联系.更多还原

【Abstract】 Bering Sea and Chukchi Sea are located in an ice margin zone where the air-sea-ice interactions are particularly intense.With the methods of moving-t abrupt test and wavelet analysis,abrupt changes of the ice extent(1953-2004) in Bering Sea and Chukchi Sea are found separately in the late of 1970s-an abrupt change of the mean value in Bering Sea and a frequency shift in Chukchi Sea.The different distributions of surface level pressure,wind(10 meter) and surface air temperature before and after the regime shift indicate that the increase of Aleutian Low,position change of its core,and the change of wind field in accordance,especially during the winter months,are the major dynamic reasons for the significant reduction of ice extent in Bering Sea.In addition to the thermal reasons,the advection of arctic sea ice(Pacific section),which is the result of dynamic factors,is closely related to the frequency shift that occurred in Chukchi Sea.This is because that frequency shift can also be found in the wind vortex over the Arctic Ocean,U-wind in Beaufort Sea,V-wind in East Siberian Sea and the PDO index.更多还原