长江流域年降水集中程度分析

Investigation on Annual Precipitation Concentration in Yangtze River Basin

针对降水量的时空分布影响旱涝灾害的防治和水资源的合理利用问题,基于长江流域80个气象站1956~2005年的逐日降水资料,以15 d为时段长度,运用年降水集中度和集中期并结合变差系数和趋势系数,分析了长江流域降水集中程度及其不同时期内的变化趋势。结果表明,50 a来降水量分布呈逐渐均匀的趋势,但1990年以来,降水较为集中,各区段降水叠加的可能性增大,为旱涝灾害的防治提供了参考依据。

The spatial and temporal distribution of precipitation amount affects the drought and flood disaster prevention,and is also closely related with the rational use of water resources.Based on daily precipitation datasets at 80 stations in the Yangtze River Valley from 1956 to 2005 years,annual precipitation concentration and variation tendency in different periods are analyzed by using precipitation concentration degree（PCD） and precipitation concentration period（PCP） with 15-days duration and combining variation coefficient with tendency coefficient.The results show that the distribution of precipitation became more homogeneous in 50 years;however,it has been relatively concentrated since 1990s and leads to increment of the possibility of precipitation overlay for each section.Thus,it provides basis for drought and flood disaster prevention.