山西春季降水与500hPa环流场及太平洋海温场异常的关系

Relations between Spring Precipitation in Shanxi and Anomalies of 500 hPa Circulation Field and SST in Pacific Ocean

利用1961—2008年春季山西省62个气象站的逐月降水资料、NCEP/NCAR再分析资料、NOAA太平洋海温资料等,应用SVD、Monte Carlo统计检验和合成分析等方法,探讨了山西春季降水与500hPa环流场及太平洋海温场的异常关系。结果表明,当春季500hPa平均高度场上,欧洲北部、日本海和北太平洋东部出现正异常,而极地、西西伯利亚出现负异常时,山西春季降水易偏多;反之,则易偏少。当春季赤道中东太平洋海温异常偏高,北太平洋东南部海温异常偏低,且前期冬季也有相似的海温距平分布时,山西春季降水易偏多;反之,则易偏少。春季,850hPa我国东部地区110°～120°E范围偏南风减弱是导致山西春季降水偏少的重要因素。

Based on the monthly precipitation data at 62 meteorological stations in Shanxi Province in spring from 1961 to 2008,NCEP/NCAR reanalysis data and NOAA sea surface temperature（SST） data in the Pacific Ocean,the relations between the spring precipitation in Shanxi and anomalies of the 500 hPa circulation and Pacific Ocean SST are studied using the SVD method,Monte Carlo statistical test and composite analysis methods.The results show that when 500 hPa mean geopotential height field in spring appears positive anomalies over the North Europe,the Japan Sea and eastern North Pacific Ocean,and the negative anomalies over west Siberia and the North Pole,it always has contemporaneous more precipitation in spring in Shanxi,otherwise spring precipitation less;when the mean SST in middle and eastern equatorial Pacific is abnormally high and the mean SST in the southeast of North Pacific is abnormally low in spring,and the areas have the similar distributions of SST anomaly in previous winter,it always appears more precipitation in Shanxi in spring,otherwise spring precipitation less.The weakened 850 hPa south wind in spring in the eastern China of 110°~120°E may cause contemporaneous less precipitation in Shanxi Province.