长江源区年最大洪峰流量与极端气候的关系分析

Analysis of the Relationship between Annual Maximum Peak Discharge and Extreme Climate in the Source Region of the Yangtze River

基于长江源区1960~2016年最大洪峰流量序列和气象资料,运用线性最小二乘法、Mann-Kendall显著性检验、Khronostat突变检验软件,分析了长江源区年最大洪峰流量的变化趋势和突变特征,并采用Spearman相关分析法探讨了洪水极值与极端气候指数之间的关系。结果表明:近57年直门达和沱沱河水文站的年最大洪峰流量均呈不显著增加趋势,变化速率分别为41.20 m3/(s•10a)和0.39 m3/(s•10a);直门达站年最大洪峰流量序列不存在突变现象,沱沱河站在1972和1995年分别发生显著减小和增大突变。长江源区7~9月1日最大降水量和连续5日最大降水量均呈不显著增加趋势,7~9月极端最高气温和极端最低气温均呈显著上升趋势,变暖速率分别为0.36℃/10a和0.32℃/10a。直门达站和沱沱河站的年最大洪峰流量均与其7~9月连续5日最大降水量显著相关,在直门达站还与7~9月极端最高气温显著负相关,沱沱河站则与7~9月极端最低气温存在显著正相关关系。研究成果可为长江源区水资源管理和防灾减灾提供科学参考。

Based on the annual maximum peak discharge (AMPD) series and meteorological observation data from 1960 to 2016 in the source region of the Yangtze River (SRYR), the trend and mutation characteristics of the AMPD were analyzed by using linear least squares method, Mann-Kendall significance test and Khronostat software. In addition, the correlations between the AMPD and extreme climate indices were explored by Spearman correlation analysis method. The results show that the AMPD at the Chumda and Tuotuohe hydrological station exhibit non-significant increasing trend in the past 57 years, with an increase rate of 41.20 and 0.39 m3/(s•10a), respectively. There is no abrupt change in the AMPD series at Chumda hydrological station, however, an abrupt decrease and increase occurred in 1972 and 1995 at the Tuotuohe hydrological station, respectively. The Max 1-day precipitation and the Max 5-day precipitation in July-September for the SRYR exhibit non-significant increasing trend. However, the maximum value of daily maximum temperature and the minimum value of daily minimum temperature in July-September for the SRYR exhibit significant increasing trend, with an increase rate of 0.32˚C and 0.36˚C/10a, respectively. The AMPD at both stations is significantly correlated with the Max 5-day precipitation in July-September. In addition, the AMPD at the Chumda hydrological station is significantly negatively correlated with the maximum value of daily maximum temperature in July-September, while there is a significantly positive correlation between the AMPD and the minimum value of daily minimum temperature in July-September at Tuotuohe hydrological station. The research results can provide a scientific basis for water resource management and disaster prevention/mitigation policies in the SRYR.