南亚高压分布特征与长江流域降水关系的数值模拟

Simulation Analysis to the Relationship between the Distribution Characteristic of SAH and the Precipitation of Yangtze River Valley

本文选用1979～2008年NCEP/NCAR第二套再分析资料,结合国家气候中心提供的160站逐月降水资料,首先分析了南亚高压各特征参数的年代际变化及各特征参数间的相关性。南亚高压面积、强度、东脊点、中心位置指数均呈现显著的年代际变化:1991年之前,面积指数偏大、强度指数偏强、东脊点位置偏东,中心位置偏东;而1991年之后(1998年除外),各特征参数的情况呈现基本相反的变化。南亚高压的面积指数与强度指数和东脊点指数的相关系数均达到了α=0.01的显著性,三者之间存在显著线性相关性。之后,采用RegCM3模式对南亚高压东脊点典型异常年份(1996、1998年)进行了模拟分析,初步分析模式模拟降水的效果:降水中心基本能模拟得到,但是降水强度模拟偏小。

Based on the NCEP/NCAR monthly mean reanalysis- 2 dataset from 1979 to 2008 and the observational monthly mean data at stations given by National Climate Center, it studies the inter - decadal variations and the relation of South Asia high（SAH）. It is found that all of the parameters of SAH exist the remarkably inter - decadal variations in summer. Before the 1991, the area index is larger, the intensity index is stronger, the east ridge point and center position of SAH is more east. After 1991, the parameters of SAH present reverse variety. The correlation analysis indicates that the area index, the intensity and east ridge point of SAH exist significant relation. This paper uses RegCM3 to simulate the situation of 1996 and 1998, which are the east ridge point of SAH representative abnormity year. Through simulation, this paper analyzes the ability of simulating precipitation of this model. The results indicate that the center of precipitation can be simulated, but the intensity of the precipitation is smaller by simulating.