岷江流域降水特征与旱涝灾害趋势分析

基于岷江流域14个气象站点1961—2012年逐月降水资料，采用数理统计方法结合GIS空间分析技术，对流域降水量时空演变特征进行了分析，利用不同尺度的标准化降水指数（SPI）对流域旱涝特征进行了研究。结果表明:（1）近52 a来，岷江流域年平均降水量呈显著减少趋势，减少倾向率为20.18 mm/10 a；流域年均降水量在1993年发生突变，降水量显著减少。（2）该流域降水量由东南向西北呈递减趋势，以松潘—小金—康定为界，该线以西地区年降水量为616～1 000 mm；该界线以东地区年降水量为1 000～1 732 mm。（3）以松潘—小金—康定为界，该界线以西降水量呈增加趋势，增加倾向率为0～27.11 mm/10 a的范围内；该界线以东降水量呈减少趋势，减少倾向率在0～80 mm/10 a的范围内。（4）岷江流域旱涝灾害阶段性变化趋势明显，1961—1967年涝灾频繁，1968—1972年干旱频率高，旱灾严重；1973—1993年涝灾频繁；1994—2012年旱灾程度与频次均呈增加趋势，旱灾严峻。（5）岷江流域旱涝灾害总体以1990年为转折点，1990年以前该区多涝灾，1990年后多旱灾，岷江流域由涝灾向旱灾转化的趋势明显，在未来一段时间应做好防旱抗旱工作。

The Analysis on Characteristics of Precipitation and Trends in Drought and Flood Disasters in Minjiang River Basin

Based on the monthly precipitation data of the 14 meteorological stations in Minjiang River Basin from 1961 to 2012, the spatiotemperal evolution characteristics of precipitation were analyzed by using the method of mathematical statistics combined with GIS spatial analysis technology, and the different scales of drought-flood were analyzed by using the standardized precipitation index (SPI). The results show that: (1) the mean annual precipitation significantly decreased in the past 52 years in Minjiang River Basin, the precipitation tendency rate was 20.18 mm/10 a; the annual average precipitation mutation occurred in 1993; (2) the precipitation in this basin showed a decreasing trend from southeast to northwest area, Songpan-Xiaojin-Kangding was recognized as the boundary, the annual precipitation was 616~1 000 mm in western area of the line; and 1 000~1 732 mm in east of the line; (3) the precipitation showed an increasing trend in western area of the Songpan-Xiaojin-Kangding, the precipitation tendency rate was 0~27.11 mm/10 a; the precipitation showed a decreasing trend in east of the boundary, decreasing trend rate was 0~80 mm/10 a; (4) there was an obvious flood to drought trend in Minjiang River Basin, it was waterlogging from 1961 to 1967, the frequency of droughts was high from 1968 to 1972, the floods were frequent from 1973 to 1993; the frequency and degree of droughts increased from 1994 to 2012; (5) It was waterlogging before 1990, and dry after 1990 in Minjiang River Basin, the trend in conversion of waterlogging to drought was obvious, so preventing and controlling drought work should be done in the next period.