A Fuzzy Clustering Iterative Model on Temporal Distribution of Precipitation and its Application

In this paper, a fuzzy clustering iterative model is introduced for studying temporal character distribution of precipitation through analysis on the rainfall sequence from 1942 to 2005. According to the clustering results of rainfall temporal distribution features, variation trend of watershed runoff under different temporal distribution pattern has been studied. Furthermore, the impact of human activities on watershed runoff has been analyzed quantitatively. Taking annual precipitation and the proportion of flood season rainfall into account for annual precipitation as characteristic criterion, the fuzzy clustering results show that the temporal distribution of annual rainfall in upstream of Fengman watershed could be divided into two categories. The watershed runoff under different precipitation categories decreased year by year due to the impact of human activities. The less and more dispersive the rainfall, dramatically stronger the influence of human activities is.