中文摘要：

以汉江流域13个站点1960～2003年的逐日降水资料为基础,分析了该流域年及各季雨日数和雨日平均雨量分布的时空特征,研究表明汉江流域春季平均雨日数占全年的25%～31%,雨量占全年雨量的21%～31%。夏季平均雨日数占全年雨日数的13%～18%,雨量占全年雨量的50%。秋季平均雨日数占全年雨日数的22%～31%,雨量占全年雨量的21%～29%。冬季平均雨日数占全年雨日数13%～22%,雨量占全年雨量的6%,雨日平均雨量仅为2.8mm。建立了流域内不同站点、不同季节的持续性雨日概率分布模式,用Polya概率分布对汉江流域各种持续性雨日发生概率进行拟合,结果表明夏季、冬季、秋季拟合效果较好,卡方检验通过率达到95%,而春季有4个站点无法通过检验。利用Polya概率分布模式可以科学地估算流域各地、各季不同持续时段雨日出现的气候概率,为防洪减灾提供依据,也为南水北调中线工程的顺利实施提供科学依据。

英文摘要：

The study of temporal trend of precipitation in river basins has been paid more and more attention.In this paper,based on the precipitation data from 13 weather stations during 1960~2003 in Hanjiang River basin,the annual and seasonal precipitation and continued rainy days were analyzed.Results showed that average rainy days in spring accounted for 25%~31% of annual rainy days,precipitation accounted for 21%~31% of annual rainfall.In summer,average rainy days accounted for 13%~18% and precipitation accounted for 50%.There were 22%~31% rainy days and 21%~29% precipitation amounts in autumn.In winter,rainfall only accounted for 6% of annual rainfall,average precipitation in rain days was 2.8 mm.Besides,continued rainy days distribution model in different station and seasons were studied.Chi-square goodness of fit tests was performed on precipitation data to compare the fit of the models.The results indicated that Polya probability distribution was statistically feasible.At the α=0.1 significance level,95% of stations in Hanjiang River basin passed the verification.But 4 stations in spring could not pass the verification.Polya probability distribution model could be used to estimate probability of continued rainy days in watershed science.It will provide guidelines for flood prevention and disaster alleviation,also will provide scientific references for the middle route of South to North Water Transfer Project in China.