南北半球高低层环流切变与长江流域夏季降水异常的关系  

RELATIONSHIP BETWEEN SUMMER RAINFALL IN THE YANGTZE RIVER AND SHEAR OF CIRCULATION ON 850HPA AND 200HPA OVER SOUTH AND NORTH HEMISPHERES

作　　者：艾秀 何敏[1] 

机构地区：[1]国家气候中心中国气象局气候研究开放实验室,北京100081

出　　处：《应用气象学报》2005年第B03期48-55,共8页Journal of Applied Meteorological Science

基　　金：国家"九五"重中之重项目"短期气候预测系统的总装与业务化试验研究"课题 (96 90 8 0 6)之子专题96 90 8 0 6 1 1;国家气象中心自筹资金"我国汛期旱涝主导因子研究"的共同资助。

摘　　要：利用奇异值分解 (SVD)方法分析和讨论了夏季 85 0hPa和 2 0 0hPa高低层纬向风距平差与我国夏季降水异常的关系 ,发现澳大利亚东北部高低层纬向风切变与长江中下游地区降水有较好的反相关 ,并定义了澳大利亚季风指数。 9个澳大利亚冬季风 (南半球 )指数低值年与 7个高值年我国夏季降水的平均差值图表明 ,显著的降水差异出现在长江中下游 ,低值年有利于长江中下游地区降水偏多 ;澳大利亚冬季风指数与夏季北半球 5 0 0hPa高度场的相关图在东亚至西太平洋的相关分布呈现出“ - + -”结构 ,在我国长江以南的中低纬和贝加尔湖的高纬地区是负相关区 ,正相关在我国北方至日本的中纬地区。The relationship between summer rainfall over China and the shear of zonal wind at 850 hPa and 200 hPa was analyzed by the method of SVD. Result shows a good relation between summer rainfall in the reaches of the Yangtze River and the shear of zonal wind at 850 hPa and 200 hPa over the northeast of Australian. The Australian monsoon index was defined as I_ AM. The distribution of rainfall difference between the 9 high I_ AM years and 7 low I_ AM years shows that the most significant difference occurs over the reaches of the Yangtze River. In the low (high) I_ AM years, summer precipitation is more (less), I_ AM also shows a notable relationship with 500 hPa geopotential height over the north hemisphere.

关 键 词：奇异值分解法 SVD 夏季 降水 长江流域 环流切变 

分 类 号：P461[天文地球—大气科学及气象学]