两类ENSO对我国华南地区冬季降水的不同影响  

Different Impacts of Two Types of ENSO on Winter Rainfall over South China

作　　者：袁良[1] 何金海[1] 

机构地区：[1]南京信息工程大学大气科学学院,江苏南京210044

出　　处：《干旱气象》2013年第1期24-31,共8页Journal of Arid Meteorology

基　　金：国家重点基础研究发展计划(973计划)"热带太平洋海洋环流与暖池的结构特征;变异机理和气候效应"(2012CB417403);国家重点基础研究发展计划(973计划)"气候变暖背景下我国南方旱涝灾害的变化规律和机理及其影响和对策"(2013CB430202);江苏高校优势学科建设工程资助项目(PAPD)共同资助

摘　　要：El Nino Modoki是近年发现的赤道太平洋海温异常分布的新特征,主要表现为热带太平洋海温异常为纬向"三极型"分布,与传统的El Nino的"偶极型"分布显著不同。本文利用1979～2010年冬季降水观测资料以及NCEP/NCAR再分析月平均资料,分析了El Nino和El Nino Modoki对我国华南地区冬季降水的不同影响。结果表明,El Nino年冬季,西太平洋副热带高压偏强偏南,我国华南地区受其西侧异常西南风影响,获得充足的水汽供应。另外,高层抽吸作用增强,上升运动加强,对流发展,降水偏多;而El Nino Modoki年冬季,西太平洋副热带高压位置偏北,我国华南地区受高压脊控制。华南地区高层抽吸作用减弱,上升运动减弱,对流减弱,并且水汽供应不足,导致降水偏少。El Nino Modoki observed in recent years displays new features of sea surface temperature anomalies（SSTA） in equatorial Pacific Ocean,which mainly shows a zonal tripolar distribution pattern of SSTA and is distinct from the traditional El Nino.Based on the precipitation data and the monthly reanalysis data provided by National Centers for Environmental Prediction/National Center for Atmospheric Research（NCEP/NCAR） from 1979 to 2010,the different impacts of El Nino and El Nino Modoki on winter rainfall over South China were analyzed.The results show that in the winter of El Nino,the western Pacific subtropical high moved southward and strengthened,and abnormal southwestly wind on its west side influenced South China and brought plenty of water vapour supply.In addition,increase of the pumping effect of upper-layer and the ascending motion,and development of convective activity resulted in more rainfall in South China.While in the winter of El Nino Modoki,the position of the western Pacific subtropical high was more northward and South China was controlled by ridge of high pressure,the upper-layer pumping effect,ascending motion and convective activity became weaker,and insufficient water vapour supply,which all resulted in less rainfall in South China.

关 键 词：ELNINO ElNinoModoki 西太平洋副高 水汽输送 

分 类 号：P458.121[天文地球—大气科学及气象学]