我国华南3月份降水年代际变化的特征  

Interdecadal Variability of Precipitation in March over South China

作　　者：李宏毅[1,2,3] 林朝晖[1] 陈红[1] 

机构地区：[1]中国科学院大气物理研究所国际气候与环境科学中心,北京100029 [2]中国科学院研究生院,北京100049 [3]中国气象局培训中心,北京100081

出　　处：《气候与环境研究》2010年第3期311-321,共11页Climatic and Environmental Research

基　　金：国家科技支撑计划2007BAC29B03;国家重点基础研究发展计划2009CB421406;国家自然科学基金资助项目40821092

摘　　要：利用1951～2005年华南3月份降水资料、太平洋年代际振荡(PDO)指数以及NCEP再分析资料,对华南3月份降水年代际变化特征、及其对应的大尺度环流以及与PDO的关系进行了分析。结果表明,华南3月份降水存在显著的年代际变化特征,并且Mann-Kendal突变检验表明华南3月份降水在1978年左右发生年代际突变,从之前的降水偏少转变为降水偏多。我国华南3月份降水与PDO有着显著的相关。进一步研究表明,在年代际降水偏少时期,PDO处于负位相(北太平洋海温偏高,中东太平洋海温偏低),北太平洋海平面气压场和高度场偏高,亚洲大陆海平面气压场和高度场偏低,赤道西太平洋到赤道东印度洋附近的海平面气压场偏低,赤道辐合带附近地区的高度场偏低,东亚对流层大气偏暖,西太平洋副热带高压偏东,东亚高空急流偏北,东亚Hadley环流偏弱。在年代际降水偏多时期,PDO处于正位相,情况则与降水偏少时期相反。The decadal variation of precipitation in March over South China and its relationship with PDO （Pacific Decadal Oscillation） are analyzed by using the observational rainfall data, PDO index, and NCEP reanalysis data. The Mann-Kendall test performed on precipitation in March over South China shows that the turning year for deeadal change in about 1978, precipitation experienced a notable low to high transition. In the decadal period of low rainfall, PDO is in negative phase （high sea surface temperature in the North Pacific, low sea surface temperature in the middle-East Pacific）, sea level pressure and height at 500 hPa in North Pacific are high, sea level pressure and height at 500 hPa on the Asian continent are low, the troposphere atmosphere in East Asia is warm, the western Pacific subtropical high is easterly, East Asian upper-tropospheric jet stream is northerly, Hadley circulation in East Asian is weak. In the deeadal period of high rainfall, PDO is in positive phase, the situation is completely the opposite The variability of the precipitation in March has a very significant correlation with PDO index in February and March, the correlation coefficients between them were positive at 99% confidence level. It can be summed up the changes of precipitation in March over South China is closely related to the changes of sea surface temperature in the North Pacific Ocean on decadal time scales, and a possible mechanism is proposed about how the PDO influences the precipitation anomaly over South China in March.

关 键 词：华南春季降水 年代际变化 太平洋年代际振荡 

分 类 号：P461[天文地球—大气科学及气象学]