1983年梅雨期及其前后云量的比较分析

A COMPARATIVE ANALYSTS OF CLOUDAGE BEFORE,IN AND AFTEN MEIYU SEASON IN 1983

本文利用GMS—1红外云图资料,计算、分析了1983年入梅前、梅雨期和出梅后的平均云量场,并计算了代表不同地区的云量时间序列功率谱以及它们与梅雨区的交叉谱,得到:1)江淮地区在入梅前云谱有两个显著峰,一个是周期为2—3日的短波,其主要影响系统是北支西风;另一个是周期长于两周的低频波,其主要影响系统是南支西风。2)梅雨期中显著周期波段在8—16天,西南季风的影响是主要的,但西风带系统对其5—8日波也有影响。3)出梅后周期长于两周的低频波非常显著,是受西南季风和东南季风共同制约的。

In this paper, the average eloudages before, in and after Meiyu season in 1983 ane calculated and analysed by using GMS-1 infrared cloud pictures. Furthermore, the power spectrum and cross spectrum of the eloudages of time series are calculated. The results obtained are as follows:1. Before the Meiyu season, the cloud spectrum in the Jiang-Huai region exists two significant peaks, one is the short wave whose period is 2-3 days and which is affected mainly by the northern branch of westerlies, another is low-frenquency fluctuation whose period is longer than two weeks, affected mainly by the southern branch of westerlies.2. In the Meiyu season, the significant peak of the cloud spectrum is in the waveband of 8-16 days, which is affected mainly by SW monsoon as well as the westerlies.3. After the Meiyu season, the low-f renquency fluctuation whose period is longer than two weeks, is extremely significant, which is controlled by the SW monsoon and the SE monsoon.