滨江流域降水时空演变规律分析

Analysis of Precipitation Change Trend in Binjiang River Basin

降水是水循环的关键环节,直接影响着径流过程和可利用水资源量的时空分布,关系到区域水资源安全和可持续发展.为了探讨气候变化下华南湿润区典型小流域降水时空演变规律,利用珠江流域北江一级支流滨江流域内及其邻近共10个站点近47年日降水量观测资料,采用非参数统计方法Mann-Kendall（M-K）趋势检验和Mann-Whitney-Pettiu （MWP）检定方法,对年、汛期/非汛期、年日最大和年月最大降水量进行分析.结果表明：滨江流域多年平均降水量呈北少南多分布,主要与区域气流走向及流域地形有关;年降水量总体呈现减少趋势,其中流域南部呈显著减少趋势,北部呈不显著减少趋势,其主要是汛期（4～9月）降水量减少,非汛期（10～翌年3月）降水量变化不大;年日最大和年月最大降水量均呈减少趋势.流域南部年降水量和汛期降水量在1983年发生了显著性变异;流域北部年最大日降水量和年月最大降水量分别在1987年和1985年左右发生显著性变异.

The precipitation is the key process in water cycle. It directly affects temporal and spatial distribution of runoff process and amount of available water resources. To investigate space-time evolution of precipitation in typical small watersheds of southern China under climate change, this paper analyzed the annual precipitation, flood season and non-flood season precipitation, annual maximum daily precipitation and annual maximum monthly precipitation by using the nonparametrie statistics including Mann Kendall trend test method and Mann-Whitney- Pettitt verification method based on the 47-year observed daily precipitation from 10 stations in the Binjiang River Basin, a tributary of the Beijiang River in the Pearl River Basin. The result shows that the multi-year average precipitation of the northern part in the basin is less than that in the south, which has close relation to regional airflow direction and valley terrain. At the same time, general decline of annual precipita- tion, including southern basin has a significant decline and the northern part shows no significant decline, which is mainly the precipitation in the flood season （April-September） reduced, while the precipitation in non-flood season （October-March in the next year） changed little. Both annual maximum daily precipitation and annual maximum monthly precipitation have a trend of decrease. The annual precipitation and flood season precipitation in the southern part of the basin had a significant variation in 1983, while in the north, the annual maximum daily precipi- tation and annual maximum monthly precipitation have respectively significant variation in 1987 and 1985.