澄碧河流域极端降水变化分析

Analysis of Extreme Precipitation Change in Chengbihe Basin

根据广西岩溶区澄碧河流域1963~2014年逐日降水资料,结合百分位计算法定义极端降水阈值,在此基础上,采用线性趋势、Mann-Kendall、Morlet小波分析及Pearson相关系数等方法分析了极端降水指数演变规律及其与年径流的关系。结果表明,极端降水量、极端降水日数和极端降水比率呈上升趋势,10年上升率分别为2.3 mm、0.034 d、0.7%,极端降水强度呈下降趋势,下降率为-0.02 mm/(d·10a),经Mann-Kendall趋势检验,上升和下降趋势均不显著;经过多种突变检验法综合诊断,极端降水量和极端降水强度的突变年份为2009年,极端降水日数和极端降水比率的突变年份为1976年;各极端降水指数周期演变特征基本一致,第一、二主周期分别为28、15年,且丰枯交替明显;极端降水量与年径流的相关性最强,极端降水强度与年径流的相关性最弱。

Based on the daily precipitation data from 1963 to 2014 in the Chengbihe Basin, a karst region of Guangxi, combined with the percentile-based threshold method, the extreme precipitation indices and its correlation with annual runoff were analyzed by using linear regression, moving average, Mann-Kendall, Morlet wavelet and Pearson correlation coefficient analysis. The results indicate that the extreme precipitation, the number of extreme precipitation days and extreme precipitation ratio showed upward trend at the 10-year ascending rate of 2.3 mm, 0.034 d and 0.7%, respectively, while extreme precipitation intensity showed downward trend at the rate of -0.02 mm/(d·10a);Through Mann-Kendall test, the trend were not significant. Through the comprehensive diagnosis of multiple mutation test methods, the abrupt year of extreme precipitation and extreme precipitation intensity was 2009, and the abrupt year of extreme precipitation days and extreme precipitation ratio was 1976. The periodic characteristics of each extreme precipitation index are basically consistent, and the first and second main period are 28 a and 15 a respectively, together with clear alternation between dry and wet years. The correlation between extreme precipitation and annual runoff is the strongest, and the correlation between extreme precipitation intensity and annual runoff is the weakest.