1962-2012年西南地区极端降水事件的时空变化特征  

Spatial and Temporal Variation in Extreme Precipitation Events in Southwestern China during 1962-2012

作　　者：袁文德 郑江坤[1] 董奎[1] 

机构地区：[1]四川农业大学长江上游林业生态工程四川省重点实验室,雅安625014

出　　处：《资源科学》2014年第4期766-772,共7页Resources Science

基　　金：中国博士后科学基金面上项目(编号:2012M511938);四川省高等学校建设项目:"水土保持与荒漠化防治重点实验室";国家"十二五"科技支撑计划项目(编号:2011BAC09B05)

摘　　要：基于西南地区90站1962-2012年逐日降水数据,采用百分位阈值法定义极端降水事件,用MannKendall秩次相关法,反距离加权插值法对西南地区的极端降水事件进行了时空变化分析。结果表明：1日最大降水量从东部的103~118mm减少到西部的25.4~46.7mm,极端降水比率从东部的39%~43%减少到西部的23%~25%。极端降水量、极端降水强度和5日最大降水量则分别从东南的508~610mm、55~64mm/d和158~190mm递减到西北的118~220mm、17~28mm/d和53~85mm。该区1日最大降水量的变异系数最大,达39%,其次为极端降水量、极端降水强度、5日最大降水量、极端降水比率,极端降水日数最小为18%;各极端降水事件因子的值均属较强变异,说明西南地区内部极端降水事件差异性较大。近50年呈上升趋势极端降水事件中,1日最大降水量、极端降水强度和极端降水比率所占比例分别达60%、64%和61%,其中呈显著上升趋势站点所占比例分别达12%、10%和13%;极端降水日数下降趋势和显著性下降趋势站点所占比例分别为52%和4%。西南地区近50年极端降水事件总体呈上升趋势,但显著性不高;这和海温异常变化和复杂的地理环境有较大关系。Based on daily precipitation data for 90 stations from 1962-2012,extreme precipitation events were defined using the percentile threshold method and analyzed in time and space using the Mann-Kendall rank correlation method and inverse distance weighted interpolation method. The results showed that annual daily maximum precipitation and the extreme precipitation ratio decreased from 103~118mm and 39% ~43% in eastern areas to 25.4~46.7mm and 23% ~25% in western areas. Extreme precipitation,extreme precipitation intensity and annual 5-days maximum precipitation decreased from 508~610mm,55~64mm/d and 158~190mm in southeast areas to 118~ 220mm,17~28mm/d and 53~85mm in northwest areas,respectively. The variation coefficient of annual daily maximum precipitation amount is the largest and up to 39%,followed by that of the extreme precipitation amount, extreme precipitation intensity, annual 5-days maximum precipitation and extreme precipitation ratio;extreme precipitation days is the smallest and only 18%. The variation coefficient of extreme precipitation events was stronger and indicates larger differences in extreme precipitation events in the southwestern region. Among extreme precipitation events from 1962-2012,sites with an upward trend for annual daily maximum precipitation amount,extreme precipitation intensity and ratio accounted for 60%,64% and 61% and the significant upward trend reached 12%,10% and 13%,respectively. Sites with an extreme downward trend and significant downward trend for extreme precipitation days accounted for 52% and 4% respectively. On the whole,extreme precipitation events followed an upward trend overall, but not significantly,on account of ocean temperature anomalies and the complex geographical environment.

关 键 词：极端降水 Mann-Kendall秩次相关法 空间分布 西南地区 

分 类 号：P468.0[天文地球—大气科学及气象学]