Impact of Greenland blocking on midlatitude extreme cold weather:Modulation of Arctic sea ice in western Greenland  

作　　者：Xiaodan CHEN Dehai LUO 

机构地区：[1]Department of Atmospheric and Oceanic Sciences&Institute of Atmospheric Sciences,Fudan University,Shanghai 200438,China [2]Key Laboratory of Regional Climate-Environment for Temperate East Asia,Institute of Atmospheric Physics,Chinese Academy of Science,Beijing 100029,China

出　　处：《Science China Earth Sciences》2021年第7期1065-1079,共15页中国科学（地球科学英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant No.41790473);the China Postdoctoral Science Foundation(Grant No.BX20200087)。

摘　　要：In this study,we analyzed 1979–2019 daily ERA-Interim reanalysis data in winter and performed atmospheric circulation experiments to examine the modulation of Arctic sea ice in western Greenland(Baffin Bay,Davis Strait,and the Labrador Sea,BDL)on winter Greenland blockings.It is found that low BDL sea ice and high BDL surface temperature favor frequent,long-lived,westward-moving Greenland blockings in winter,which cause frequent and strengthening cold surges over the mid-eastern United States.In contrast,high BDL sea ice and low BDL surface temperature favor short-lived,less frequent and quasi-stationary Greenland blockings,mainly leading to cold anomalies in North Europe.Low wintertime BDL sea ice reduces the background potential vorticity meridional gradient(PVy)and zonal wind over the mid-high latitudes of the North Atlantic,which enhances the nonlinearity of Greenland blocking,accelerates the phase speed of its westward movement,and weakens its energy dispersion,thus favoring the occurrence and persistence of Greenland blocking.High BDL sea ice strengthens the background PVyand zonal wind in the mid-high latitudes of the North Atlantic,which weakens the nonlinearity and movement of Greenland blocking,enhances its energy dispersion,and thus suppresses the occurrence and persistence of Greenland blocking and its retrogression.A set of atmospheric circulation experiments supports the above results based on the reanalysis dataset.

关 键 词：Arctic sea ice Greenland blocking Meridional gradient of potential vorticity Extreme cold weather 

分 类 号：P44[天文地球—大气科学及气象学] P732.6