100hPa南亚高压特征向量及其与我国夏季降水关系

EIGENVECTORS OF 100 hPa SOUTHERN ASIA HIGH AND ITS RELATIONSHIP WITH SUMMER RAINFALL IN CHINA

摘要:

本文对10°-40°N,60-130°E的区域内的1956-1984年4到8月的月平均100hPa位势高度进行了经验正交函数(EOF)分析,分离出了主要四个特征向量场,它们分别表示了南亚高压的平均强度,南北摆动、东西振荡和脊线走向的主要特征,为进一步分析南亚高压及其活动特征提供了新参数。本文还分析了南亚高压的主要活动特征与我国夏季降水的关系,分析结果表明南亚高压及其活动特征对我国夏季降水具有重要影响,这与天气经验是一致的。它们与降水的相关关系也为长期预报提供了参考依据。

Abstract:

Monthly mean 100hPa geopotential heights for five months(APR. - AUG. ) from 1956 through 1984 in the area 10-40°N, 60- 130 °E)are analized by EOF method. Four eigenvectors selected acording to their contributions to total covariance repre sent respectively the major characters of Southern Asia High(SAH), i. e. mean strength, south-north oscilatiori, east-west oscilation and ridge-line tilt. Similar analysis is used to the rainfall anormalies for summer season in 11 subareas. Analysis on time coefficients of SAH and the rainfall show significant effects of SAH behaviour on summer rainfall in China, which is consistent with synoptic experiences. The self correlation of time coefficient and relationship between two time coefficients may offer a way to long range rainfall forecasting.