近46年来东江流域降水变化趋势分析

Analysis of Precipitation Change Trend over Last 46 Years in Dongjiang River Basin

运用非参数检验Mann-Kendall方法对东江流域近46年来降水变化趋势的时空特征进行分析,结果表明:近46年来东江流域年降水量呈现出增加趋势,但未达到显著性水平,增加速率为16.02mm/10a;流域年降水日数表现为不显著的减少趋势,递减率为0.51d/10a,6月份降水日数的显著减少对全年降水日数的减少趋势贡献率最大;流域年平均降水强度总体变化趋势不明显,变化率为0.16mm/d.10a,其中7月份增强幅度最大(0.9mm/d.10a),对全年降水强度的变化趋势贡献率最大;近46年来东江流域年降水量、降水日数及平均降水强度的变化趋势在空间分布上都存在一定的区域差异性。

This paper analyzed temporal and spatial characteristics of precipitation change trend over the last 46 years in the Dongjiang River basin.The results showed that the annual precipitation in the Dongjiang River basin had an increase trend,which increased at a rate of 16.02mm/10a,but it did not arrive at a =0.05 statistically significant level;Annual rain days in the Dongjiang River basin showed an unobvious decrease trend,successive decrease rate was 0.51d/10a and it was mainly due to higher rate of rain days increase in June;Mean annual rain intensity in the Dongjiang River basin did not appear to an obvious trend,and its gradients was 0.16 mm/d.10a,which was mainly to the highest rate（0.9 mm/d.10a） in July;The spatial distribution of chage trend of annual precipitation,rain days and mean rain intensity exhibited an extent regional variation.