北极海冰加速融化的年代际突变东西半球非同步特征

The Non-Simultaneous Characteristic in the Decadal Shift of Arctic Sea Ice Melting between the Western and Eastern Hemispheres

摘要: 随着全球变暖北极放大效应，北极海冰加速融化。本文利用美国国家冰雪数据中心提供的1979~2019年逐月海冰密集度数据，通过构建表征海冰加速融化的平均海冰密集度和海冰面积指数，系统分析了北极海冰加速融化的年代际变化特征。研究发现，1979~2019年北极海冰密集度和海冰面积均呈现出年代际振荡减小的特征，但年代际转折时间表现为空间不一致性特征，特别是东西半球海冰年代际转折呈现出非同步的变化特征，西半球普遍早于东半球。西半球的格陵兰扇区最早出现海冰的加速融化，四个季节的年代际突变均发生在1997~1998年；东西半球过渡区域的太平洋扇区在2002年前后出现年代际转折，且只显著发生在夏季和秋季；东半球的欧亚扇区海冰面积的年代际突变时间最晚，四个季节均在2004年前后出现年代际转折现象。

Abstract: According to the global warming and the Arctic amplification, the loss of Arctic sea ice accelerates. Based on the monthly sea ice concentration data from the US National Snow and Ice Data Center from 1979 to 2019, this paper systematically analyzed the interdecadal characteristics of the accelerated melting of Arctic sea ice by constructing the mean sea ice concentration (SIC) and sea ice area (SIA) index, which represents the accelerated melting of sea ice. The results show that the decadal oscillation decreases in both Arctic SIC and SIA from 1979 to 2019, but the time of decadal shift is spatially inconsistent. In particular, the decadal shift time of the Arctic eastern and western hemispheres is asynchronous, and the western hemisphere is generally earlier than the eastern hemisphere. The Greenland sector of the Western Hemisphere was the first to show accelerated sea ice melting, and the decadal shifts of the four seasons all occurred in 1997~1998. The decadal shift in the Pacific sector of the eastwest hemisphere transition region occurred around 2002, and only occurred in summer and autumn. In the Eurasian sector of the Eastern Hemisphere, the time of decadal shift of SIA was the last, and the decadal transition occurred in all four seasons around 2004.