2011年夏季西南极端干旱事件及其成因  

Extreme drought event and its causes in Southwest China in summer 2011

作　　者：蓝天 霍利微 王冀[3] 邓汗青[4] 王易[5] 柳春[6] 张茜 LAN Tian;HUO Liwei;WANG Ji;DENG Hanqing;WANG Yi;LIU Chun;ZHANG Qian(Key Laboratory of Meteorological Disaster,Ministry of Education (KLME)/Joint International Research Laboratory of Climate and Environment Change (ILCEC)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters (CIC-FEMD),Nanjing University of Information Science and Technology,Nanjing 210044,China;Guizhou Branch of Southwest Air Traffic Management Bureau of Civil Aviation of China,Guiyang 550025,China;Beijing Regional Climate Center,Beijing 100089,China;Anhui Climate Center,Hefei 230031,China;Jiangsu Meteorological Observatory,Nanjing 210008,China;Anhui Meteorological Observatory,Hefei 230031,China;Wuxi university,College of Atmosphere and Remote Sensing,Wuxi 214105,China)

机构地区：[1]南京信息工程大学气象灾害教育部重点实验室/气候与环境变化国际合作联合实验室/气象灾害预报预警与评估协同创新中心,江苏南京210044 [2]中国民航贵州空中交通管理分局,贵州贵阳550025 [3]北京市气候中心,北京100089 [4]安徽省气候中心,安徽合肥230031 [5]江苏省气象台,江苏南京210008 [6]安徽省气象台,安徽合肥230031 [7]无锡学院大气与遥感学院,江苏无锡214105

出　　处：《大气科学学报》2021年第6期927-937,共11页Transactions of Atmospheric Sciences

基　　金：国家重点研发计划重点专项(2019YFC1510201);国家自然科学基金青年科学基金项目(42088101,42005016);安徽省自然科学基金青年项目(2008085QD190);江苏省高等学校自然科学研究面上项目(19KJB170024)。

摘　　要：利用近30 a中国地面气象台站1767站的逐月降水资料、同期NOAA的扩展重建(Extended Reconstructed SST V3b)海表温度资料和NCEP/NCAR大气再分析资料,分析了2011年夏季(6—8月)东北太平洋海温异常对西南地区极端干旱事件的影响机理。结果表明:2011年夏季西南地区降水呈现极端偏少的特征,区域平均降水距平为-270 mm,小于负两倍标准差,降水负异常极小值区域主要位于滇黔桂三地交界处。2011年夏季西南地区降水极端负异常与东北太平洋海表温度异常偶极型(NorthEast Pacific SSTA Dipole,NEPD)分布存在联系。将热带东北太平洋[90°~120°W,5°~20°N]海温负/正异常、中纬度北太平洋[150°~170°W,37°~45°N]海温正/负异常定义为NEPD负/正位相。NEPD负位相事件引起了热带中东太平洋对流层低层东风异常,并通过中纬度纬向东传波列引起远东地区位势高度正异常,减弱了西太平洋副热带高压,不利于西南暖湿气流向中国西南地区输送;同时,西南地区对流层低层辐散、高层辐合,受异常下沉气流控制。上述条件共同作用造成了2011年西南地区夏季降水极端负异常。Based on the monthly precipitation data of 1767 stations in China,NOAA sea surface temperature data of Extended Reconstructed SST V3b and NCEP/NCAR atmospheric reanalysis data in recent 30 years,this paper studies the influence mechanism of Northeast Pacific sea surface temperature anomaly on the extreme drought event in Southwest China in summer(from June to August)2011.Results show that the precipitation in Southwest China is extremely below normal in summer 2011.The regional average precipitation anomaly is-270 mm,less than negative twice standard deviations.The minimum area of negative precipitation anomaly is mainly located at the junction of Yunnan,Guizhou and Guangxi Provinces.In summer 2011,the extreme negative precipitation anomaly in Southwest China is closely related to the negative phase of Northeast Pacific SSTA dipole(NEPD),which presents the negative SSTA in the tropical Northeast Pacific[5°—20°N,90°—120°W]and the positive SSTA in the mid-latitude North Pacific[37°—45°N,150°—170°W].The negative phase of NEPD event causes anomalous easterlies in the lower troposphere over the tropical central and eastern Pacific,causes the positive geopotential height anomaly in the Far East by triggering the propagation of the quasi-stationary Rossby wave train from west to east,and weakens the western Pacific subtropical high,which is not conducive to the transportation of warm and humid air from the southwest to Southwest China.Meanwhile,Southwest China is controlled by abnormal downdraft with the lower tropospheric divergence and upper tropospheric convergence.The above conditions together cause the extreme negative anomaly of summer precipitation in Southwest China in 2011.

关 键 词：西南地区 夏季降水 东北太平洋 海温异常 偶极型 

分 类 号：P45[天文地球—大气科学及气象学]