杭州城市环境对降水影响的统计分析

Effect of Urban Environment on Precipitation at Hangzhou by Statistical Analysis

本文使用杭州地区1962—1981年的降水资料,进行统计分析后,发现杭州城市环境使降水量增加了约13—15％,多雨区位置有随风向改变的现象。

In the article, the author has made a statistical analysis upon the rainfall data from 34 hydrologic station within a radius of 50 km during 1962-1981 (with Hangzhou city as the center). By analysing the background of annual rainfall and comparing rural precipitation with urban precipitation in the network of station, abnormal phenomena for rainfall have been identified at Hangzhou area. The result shows that the city has increased approximately 13-15% value of precipitation. A distributive pattern of precipitation in the space indicates that high value area of rainfall is situated in the west-south-west part of the city in spring and summer, and south or southwest part of the city in autumn and winter. As the author associates distributive pattern of seasonal rainfall in space with wind direction, the results illustrate that high value area for rainfall is always situated in a downwind region of the prevailing wind in every season, and that the high value area is almost ''turned' regularly with seasonal prevailing wind direction.