摘要
利用1960 2004年NCEP/NCAR全球再分析资料和中国160个测站逐月降水观测资料,考虑赤道海温强迫和中高纬地区气候变化中大气环流的桥梁作用,首先对冬季印度洋海温距平场与同期北半球500 hPa位势高度距平场进行奇异值分解(SVD),然后分析印度洋海温异常对中国冬季及后期春季降水的影响。结果表明,印度洋冬季海温距平场第一奇异向量是全区一致的单极型分布形势,而且对中国春季降水的影响显著,特别是与长江中下游以北至华北地区、新疆等大片地区的春季降水呈显著正相关关系。当印度洋冬季海温距平场第一奇异向量处于正位相的时候,海温异常偏暖,此时对应的东亚地区上空西风急流减弱,日本海附近500 hPa位势高度出现正异常中心,使得东亚大槽偏东、偏弱,有助于低层偏南气流带来的水汽在长江中下游以北至华北地区形成水汽辐合,从而造成该地区春季降水偏多。因此,印度洋冬季海温距平场的第一奇异向量可以作为次年长江中下游以北至华北地区春季降水季节预报的一个前期预报因子。
The influence of sea surface temperature anomalies( SSTA) of Indian Ocean in wintertime on the interannual variability of the precipitation over China in spring were investigated by using NCEP /NCAR reanalysis and the monthly mean precipitation at 160 meteorological stations in China from 1960 to 2004. The leading patterns are obtained by applying a singular value decomposition( SVD) analysis between 500 hPa geopotential height anomalies( Z500) in the Northern Hemisphere and SSTA in the Indian Ocean. The oceanic components of the leading SVD modes are uniformly signed Indian Ocean Basin-wide( IOB) mode and the corresponding atmospheric components are PNA-like pattern. Temporal correlation coefficients between the spring precipitation over China and principal components of the leading SVD mode show that the precipitation over the middle and lower reaches of the Yangtze River of the North China region in spring can be significantly influenced by the first pair of SVD mode( SVD1). When the Indian Ocean SST is the positive phase of SVD1,the East Asian jet stream and the East Asian trough become weaker than normal leading to more transportation of water vapor to central eastern China from southeastern coast of East Asia and therefore are favorable for more-than-normal precipitation in spring over there.
出处
《高原气象》
CSCD
北大核心
2014年第3期733-742,共10页
Plateau Meteorology
基金
国家自然科学基金项目(41105073)
中央高校基本科研业务费专项(2012XZZX012)
关键词
春季降水
印度洋海温异常
奇异值分解(SVD)
Spring precipitation
Indian Ocean sea surface temperature anomalies
Singular value decomposition
