1960-2015年岷江上游松潘县降水变化与旱涝灾害

Research on the Precipitation Change and Drought-flood Disasters in Songpan Region in the Upper Reaches of Minjiang River during 1960-2015

利用岷江上游松潘县等站点的降水观测资料,分析1960—2015年间松潘县的降水变化特征,并基于SPI指数及其旱涝等级划分标准,采用M-K突变检验、功率谱及小波分析、R/S趋势分析等方法,探究岷江上游区降水规律、旱涝灾害及成因等问题.结果表明:1960—2015年松潘县降水序列的气候变化倾向率是1.09 mm/Da,年降水量总体上呈现不显著的增加趋势,存在约5.75、8.5和10~15 a的震荡变化周期.2013年松潘县降水发生突变,转为增多趋势.近55 a松潘地区旱涝频繁发生,1960—1969年、1984—2012年是少雨干旱期,但是1990年以后旱涝频率增大.1970—1983年是多雨洪灾多发期.2013年以来洪灾多发.夏季风活动强弱是引发旱涝灾害的主要成因,在年降水距平值变化显著的年份都有较大旱涝灾害发生,降水过度集中时也会出现洪灾.未来几年本区降水仍是增多趋势,加上极端气候事件多发等多重因素叠加影响,洪灾发生概率增加.

Using the observed annual precipitation data of Songpan region in the upper reaches of Minjiang River,this paper analyzes the characteristics of precipitation change during 1960—2015.Based on the SPI index and its classification standard of drought-flood disasters,M-K mutation test,power spectrum and wavelet analysis,and R/S trend analysis,etc,the precipitation law,drought and flood disasters and their causes in the upper reaches of Minjiang River are studied.The results show that:during 1960—2015,the tendency rate of climate change in Songpan county is 1.09mm/10a,On the whole,the annual precipitation shows a slight increase trend.There are about 5.75 years,8.5 years and 10-15 years of fluctuating periods of annual precipitation.In 2013,the annual precipitation changed to an increasing trend.In the past 55 years,there have been frequent droughts and floods in Songpan,1960—1969 and 1984—2012 are the dry periods with little rain,but since the 1990s,the frequency of drought and flood disasters has increased.1970—1983 is a rainy and flood prone period.Since 2013,there have been many flood disasters.Summer monsoon activity is the main cause of drought and flood disasters.In the years with significant change of annual precipitation from the average value,there are large droughts and floods,and there will also be flood disasters in precipitation concentration.In the next few years,the annual precipitation in this area is still increasing.In addition to the common influence of extreme climate events and other factors,the probability of flood disasters increases.