Research On The Drought Features Of Taihu Basin Using The Nonparameter Statisticial Method

The frequency where happen flood and drought is very high in China. along with economic development, population increment and precipitation distribution imbalance, the frequency is more and more high. Regional or basin drought strongly depends on precipitation, temperature, physiographic characteristics, composition of plants and other factors. Due to the limitation of data, the factors mentioned above can't be considered in analysis and evaluation models, so we must catch the most important factor which can result in drought. A method in terms of splitting response unit in the study basin, nonparametric estimation method incorporated with wandering analysis theory were presented to study on the regional drought index, by means of point drought index to evaluate are al drought was presented, and was used to evaluate the historical drought situation in the paper.In terms of the features of rainfall station, selected the data series of 12 rainfall staions by cluster analysis system, then calculated the drought index of these stations, which can be transformed to areal drought index basised on the weight of the stations, obtained the rate zones of drought index trought comparing to practical drought. Splited the basin to four zones, calculated the drought index of the typical stations from 1951—1990, anaylsised the drought peculiarity of the four zones. The degree which is affected by drought is most serious in Zhexi zone, Huxi zone is subsequent, Huangpu zone is the least. The paper anaylsed the probability of areal drought encounter of the four zones, the probability of taking place drought at the same time is the largest between Zhexi zone and Huxi zone. The mass of the drought events in Taihu basin take place in summer and autumn, the probability which there happen drought persisting more than two seasons is very low.The nonparametric estimation drought index is receivability for Taihu basin.The evaluation method of the nonparametric estimation can be widely used to assessdrought situation during face stage in Taihu Basin.