近50年来四川盆地降水日数的时空变化特征

利用1960—2010年四川盆地16个气象站逐日降水资料,采用距平统计法、线性趋势法、Mann—Kendall检验法及Kriging插值法对该区近50a降水日数及不同等级降水日数的时空分布特征进行了定量分析。结果表明:(1)四川盆地降水发生日数总体呈减少趋势,且从20世纪90年代开始出现以来延续至今;不同等级降水日数均呈减少趋势,其中小雨日数减少最明显,对降水日数减少的贡献最多。(2)四川盆地降水日数的减少是一种突变现象,突变年份为1994年。(3)四川盆地年均降水日数总体表现为西部、南部较多,东部、北部较少。(4)四川盆地西部、北部降水日数减少趋势较快,这种减少趋势可能是对全球变暖的区域响应;不同等级降水日数的趋势随地域的变化存在很大差异,其中东北部暴雨日数的小幅增加趋势使得地质灾害发生的可能性增加。

Spatio-temporal Variation of Precipitation Days of Sichuan Basin in Nearly 50 Years

Based on the daily precipitation data of 16selected meteorological stations over 1960—2010in Sichuan Basin,this papaer analyzed the spatio-temporal distribution characteristics of annual mean precipitation days and different levels precipitation days by applying multiple analysis methods.The results indicated as follows.(1)The precipitation days occurring in Sichuan Basin showed a decreasing tendency,which started since the 1990sand continued to now.(2)The decreasing of precipitation days of Sichuan Basin was a mutation phenomenon,which began from 1994.(3)The distribution of the annual mean precipitation days mainly showed that the more in west and south,while the less in east and north.(4)The precipitation days in west and north area of Sichuan Basin decreased rapidly.This decreasing tendency might be a result from the global warming.The regional distribution of precipitation days changed a lot with different levels.The increasing tendency of rainstorm days in northeast made more possibilities of geological disasters compared than ever before.