Effect of Urbanization on Regional Precipitation in the Qinhuai River Area, East China

Abstract

The Qinhuai River, one of the most economically developed areas in China, is also one of the largest urban agglomerations in the world. Recently, rapid urbanization has caused great changes in the regional natural environment and processes of precipitation. Taking 6 precipitation stations for daily rainfall data from 1961-2006 and using statistical analysis, linear regression, R/S method, concentration ratio and concentration period, focusing on the effects of urbanization on the long term precipitation, comparing the annual precipitation, flood season precipitation, winter precipitation, storm rainfall days and precipitation days, rainfall concentration ratio and concentration period in urban and suburban gauges, this paper probes into the effect of urbanization on local precipitation. The results show that with the development of urbanization, the increasing trend of annual precipitation, flood season precipitation and storm rainfall days in urban areas is more than the suburban areas; the increasing speed of annual precipitation and flood season precipitation in urban area are 25.16 mm/10 a and 12.0 mm/10 a, while the suburb’s are 20.28 mm/10 a and 7.3 mm/10 a respectively. The difference of urban and suburban areas is increasing and the urban rain island effect is evident. The annual precipitation is usually concentrated in June and July, the precipitation concentration ratio is on the decline in urban and suburban areas, and the rate of decrease in suburban areas is slightly more than urban areas, the difference of urban and suburban areas is little.