1980~2019年中亚夏季地表气温的异常增暖  

Abnormal Warming of the Summer Surface Air Temperature in Central Asia from 1980 to 2019

作　　者：贾晓静[1] 刘栩可 钱奇峰 Xiaojing JIA;Xuke LIU;Qifeng QIAN(Department of Earth Sciences,Zhejiang University,Hangzhou 310027;Zhejiang Institute of Meteorological Science,Hangzhou 310017)

机构地区：[1]浙江大学地球科学学院,杭州310027 [2]浙江省气象科学研究所,杭州310017

出　　处：《大气科学》2023年第3期825-836,共12页Chinese Journal of Atmospheric Sciences

基　　金：国家自然科学基金项目42075050、42205020;浙江省自然科学基金项目LQ23D050003。

摘　　要：本文利用1980~2019年NCEP/NCAR全球再分析资料、CRU地表气温资料、积雪覆盖率资料和全球海温资料,分析了中亚夏季地表气温的气候突变及其和北大西洋海温、青藏高原积雪之间的关系。结果表明:中亚夏季地表气温在2005年发生明显的气候突变。标准化的中亚区域平均的气温指数从之前的负位相为主变为之后的正位相为主,表示中亚地区夏季地表气温显著增温。和中亚夏季地表气温异常增温相联系的大气环流场的分析表明,2005年之后,中亚地区西侧的反气旋性环流系统异常增强,该反气旋异常对应的大气下沉增暖以及反气旋异常增强引起的云量减少进而导致向下的短波辐射增加均有利于中亚夏季气温异常升高。进一步的合成分析表明,中亚夏季地表气温在2005年的气候突变和北大西洋中高纬度地区的海表温度的增暖和青藏高原西部积雪的减少有着密切关系。北大西洋中高纬度海表温度增温能激发一个向下游传播的罗斯贝波,青藏高原西部积雪减少能够通过积雪的反照率效应对上空的大气有增温作用,两者均能增强中亚地区上空的反气旋系统,从而有利于中亚夏季地表气温异常偏高。This work analyzes the abrupt change in summer surface air temperature(SAT)in Central Asia(CA)and its relationship with sea surface temperature(SST)in the North Atlantic and snow cover in the Qinghai Tibet Plateau between 1980 and 2019 based on NCEP/NCAR reanalysis data,CRU SAT,and snow cover and global SST data.The results reveal a significant summer SAT change in CA in 2005.The standardized regional average temperature index in CA shifts from the previous negative phase to the subsequent positive phase,indicating a significant summer SAT increase in CA.Analysis of the anomalous atmospheric circulations related to interdecadal changes in summer SAT in CA shows the abnormally enhanced anticyclonic circulation system in the west of CA after 2005.The atmospheric subsidence associated with the anomalous anticyclone can cause warming.On the other hand,the reduction in the amount of cloud caused by this anticyclone anomaly enhancement results in the increase in downward short-wave radiation and thus is favorable for the increased summer temperature in CA.Furthermore,the interdecadal summer SAT changes in CA in 2005 are closely related to SST warming in the middle and high latitudes of the North Atlantic and the reduction in snow cover in the west of the Tibet Plateau(TP).The SST increase in the middle and high latitudes of the North Atlantic can stimulate a Rossby wave propagating downstream.The reduction in snow cover in the west of the TP can cause warming to the above atmosphere through the snow albedo effect.The changes in both the North Atlantic SST and the TP snow can strengthen the anticyclone over CA,leading to an abnormally high summer SAT over there.

关 键 词：中亚地区 地表气温 气候突变 北大西洋海温 青藏高原积雪 

分 类 号：P476[天文地球—大气科学及气象学]