2016~2017年秋冬季北极海冰异常与大气环流的关系

The Relationship between Arctic Sea Ice Anomalies and Atmospheric Circulation in the Autumn and Winter of 2016-2017

2016~2017冬季,年北极海冰范围创下自1979年以来最低记录。本文利用美国冰雪数据中心(NSIDC)的北极海冰范围指数和NCEP/NCAR大气再分析数据,分析了2016~2017年秋冬季北极海冰的变化特点及其与大气环流的关系。2016~2017年秋冬季北极海冰远低于多年平均值,并且出现了若干次海冰减少或海冰发展停滞的现象。两个主要海冰异常区为巴伦支–喀拉海和东西伯利亚–楚科奇–波弗特海,其中巴伦支–喀拉海海冰异常最为明显。对北半球中高纬度大气环流的分析发现,2016年10月~11月,持续的、异常的大气环流是影响大气温湿度进而影响海冰的原因。异常高压对西风急流的引导作用使得大气从北大西洋和北太平洋向北冰洋运动,引起北极上空大气增温、水汽增加则导致长波辐射。2016年11月~2017年3月,没有明显的持续性的环流异常,但是在较短的时间尺度上,依然有强烈的平流作用使得大气升温,从而影响了海冰。

Arctic sea ice extent hit a record low in the winter of 2016-2017.In this paper,Arctic sea ice extent index data and NCEP/NCAR atmospheric data were used to analyze the variation characteristics of Arctic sea ice during the 2016-2017 autumn and winter,and its relationship with atmospheric circulation.In the autumn and winter of 2016-2017,the Arctic sea ice was far lower than the multi-year average,and there were several times of sea ice reduction or stagnation of sea ice development.The two main sea ice anomaly areas are the Barents-Kara Sea and the East Siberia-Chukchi-Beaufort Sea.Analysis of the atmospheric circulation in the middle and high latitudes of the northern hemisphere found that from October to November 2016,the continuous and abnormal atmospheric circulation was the reason for affecting the atmospheric temperature and humidity,and thus the sea ice.The guidance of the westerly jet by the anomalous high pressure makes the atmosphere move from the north Atlantic and north Pacific to the Arctic Ocean,which results in the increase of atmospheric temperature and water vapor over the Arctic and the long-wave radiation.From November 2016 to March 2017,advection is the main effect on local atmosphere.