重庆市沙坪坝区1951—2020年降水分析

Analysis of Precipitation in Shapingba District of Chongqing from 1951 to 2020

基于重庆沙坪坝区1951—2020年的降水数据,利用Mann-Kendall突变检验、集合经验模态分解和重标极差分析等方法研究了该区域降水特征和未来降水趋势。结果表明,除了秋季,沙坪坝区在1951—2020年的年降水量和春季、夏季、冬季降水量均呈现增多的趋势。此外,沙坪坝区在研究时段的年降水日数呈现出减少的趋势,而年大雨日数和暴雨日数呈现出增多的趋势。其中,年降水日数在1982年出现突变,年大雨日数在2017年出现突变。对年降水量进行周期分解发现,2~7年的周期方差贡献率最大,这与ENSO事件发生的周期类似,表明沙坪坝区的年降水量周期变化可能与ENSO事件有关。基于重标极差分析计算的Hurst指数结果显示,沙坪坝区年降水量和四季降水量在未来可能呈现出减少的趋势。

Based on the precipitation data from 1951 to 2020 in Shapingba District, Chongqing, the precipitation characteristics and future precipitation trend in this area are studied by using Mann Kendall mutation test, ensemble empirical mode decomposition and rescaled range analysis. The results show that except for autumn, the annual precipitation and the precipitation in spring, summer and winter in Shapingba District during the period 1951-2020 all showed an increasing trend. In addition, the number of annual precipitation days in Shapingba during the study period showed a decreasing trend, while the number of annual heavy rain days and torrential rain days showed an increasing trend. The number of annual precipitation days suddenly changed in 1982 and the number of annual heavy rain days suddenly changed in 2017. The periodic decomposition of annual precipitation shows that the variance contribution rate of the period of 2-7 years is the largest, which is similar to the period of ENSO events, indicating that the periodic changes of annual precipitation in Shapingba may be related to ENSO events. The Hurst index calculated based on the rescaled range analysis method shows that the annual precipitation and seasonal precipitation in Shapingba may show a decreasing trend in the future.