川渝地区春季降水的年际和年代际变化特征

Characteristics of Interannual and Interdecadal Changes of Spring Precipitation in Sichuan-Chongqing Region

摘要: 本文利用1961~2017年川渝地区春季各月(3~5月)的逐年月降水格点数据，基于线性倾向估计法和EOF经验正交分解法，对该区春季降水量时空分布特征进行了研究。结果表明：川渝地区近60年来春季降水量整体略呈增加趋势，其中4月降水量呈下降趋势，但均没有达到显著性水平。在年代际时间尺度上，川渝地区春季降水也没有明显变化特征。川渝地区春季降水主要包括三种模态，即降水异常一致型(全局型)是最主要的模态，其次为东北–西南型，强度最弱的是东西型。

Abstract: Based on the monthly precipitation grid data of spring months (March to May) in Si-chuan-Chongqing region from 1961 to 2017, the temporal-spatial distribution characteristics of spring precipitation are studied in terms of linear tendency estimation and empirical orthogonal function (EOF). The results show that the spring precipitation presents a slight increase trend on the whole in the Sichuan-Chongqing region with a decrease trend in April, while all of trends do not reach the significant level. In addition, the spring precipitation also does not show significant interdecadal variability. The spring precipitation in Sichuan-Chongqing region is divided into three common distributive modes with the analysis of EOF method. The first distributive mode is the homogenous of precipitation anomalies, which is the most important mode. The second distributive mode is the pattern of Northeast-Southwest. The third distributive mode is the pattern of East-West, which is the most weak, is the pattern of East-West.