The Variation Characteristics Research of The Area Where PrecipitationReduced Significantly in China Last Five Decades

摘要

Based on precipitation trend map of 597 stations in China,this paper selected 96 stations where precipitation reduced significantly through 90% significance test during 1960-2009 ,and studied its variation characteristics mainly using Mann-Kendall test.The results show that annual precipitation in 96 stations show a apparent downward tendency which is in the magnitude order of 10~3.The mutation time of precipitation Is determined as 1979.The aunnal precipition amount of spring and autumn are smaller than summer,and winter is- the least.Except winter,another three seasons have decrease trend,especially summer.During fifty years, whatever total precipitation amounts or precipitation days, moderate rain and under (0.1mm-lOmm)show a upward trend, while moderate rain and over(>10mm)show a decline trend.