Change in Sea Ice Cover is Responsible for Non-Uniform Variation in Winter Temperature over East Asia  

作　　者：LI Fei WANG Hui-Jun GAO Yong-Qi 

机构地区：[1]Nansen-Zhu International Research Centre, Institute of Atmospheric Physics, Chinese Academy of Sciences [2]Climate Change Research Center, Chinese Academy of Sciences [3]Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Nanjing University for Information Science and Technology [4]Nansen Environmental and Remote Sensing Center and Bjerknes Centre for Climate Research

出　　处：《Atmospheric and Oceanic Science Letters》2015年第6期376-382,共7页大气和海洋科学快报（英文版）

基　　金：supported by the Public Science and Technology Research Funds Projects of Ocean(No.201205007);the National Natural Science Foundation of China(Grant Nos.41421004 and 41130103);the Special Fund for Public Welfare Industry(Meteorology)(Grant No.GYHY2013-06026);the Nord Forsk-funded project GREENICE(No.61841):Impacts of Sea-Ice and Snow-Cover Changes on Climate,Green Growth,and Society

摘　　要：Observed winter(December–February)surface air temperature over East Asia(0°–60°N,100–140°E)(TEA)shows non-uniform variation during 1979–2013,with cooling and weak warming north and south of40°N.To understand this,the authors perform statistical analysis(linear regression and composite)on the observed data.The results suggest that reduced(increased)autumn sea ice cover in the Barents-Kara Sea(BK-ASIC)lowers(warms)TEA over northern East Asia,which is consistent with previous studies.In comparison,increased(decreased)winter sea ice cover in the Sea of Okhotsk(O-WSIC),warms(cools)the air over southern East Asia.The mechanism can be described as follows:When the BK-ASIC decreases,the East Asian winter monsoon tends to be stronger with an intensified Siberian high,leading to cooling over northern East Asia.An O-WSIC increase is associated with cold anomalies north of 50°N,altering the meridional temperature gradient between the midlatitudes and tropics,and leading to a northward shift of the East Asian jet steam in the upper troposphere.In the low atmosphere,anomalous northeasterly winds prevail north of50°N and anomalous southerly winds control the southern coast of East Asia,contributing to the weak warming over southern East Asia.Version 3 of the Community Atmosphere Model also provides evidence for the impact of increased O-WSIC on the warm southern mode of TEA.Observed winter(December–February)surface air temperature over East Asia(0°–60°N,100–140°E)(TEA)shows non-uniform variation during 1979–2013,with cooling and weak warming north and south of40°N.To understand this,the authors perform statistical analysis(linear regression and composite)on the observed data.The results suggest that reduced(increased)autumn sea ice cover in the Barents-Kara Sea(BK-ASIC)lowers(warms)TEA over northern East Asia,which is consistent with previous studies.In comparison,increased(decreased)winter sea ice cover in the Sea of Okhotsk(O-WSIC),warms(cools)the air over southern East Asia.The mechanism can be described as follows:When the BK-ASIC decreases,the East Asian winter monsoon tends to be stronger with an intensified Siberian high,leading to cooling over northern East Asia.An O-WSIC increase is associated with cold anomalies north of 50°N,altering the meridional temperature gradient between the midlatitudes and tropics,and leading to a northward shift of the East Asian jet steam in the upper troposphere.In the low atmosphere,anomalous northeasterly winds prevail north of50°N and anomalous southerly winds control the southern coast of East Asia,contributing to the weak warming over southern East Asia.Version 3 of the Community Atmosphere Model also provides evidence for the impact of increased O-WSIC on the warm southern mode of TEA.

关 键 词：East Asia WINTER temperature ARCTIC sea ice COVER 

分 类 号：P731.15[天文地球—海洋科学] P461.2