Variation Characteristics Analysis of Extreme Precipitation Indexes in Dongtinghu Lake Basin

Based on the daily precipitation data of 17 hydrological stations during 1961-2009,four extreme precipitation indices in the Dongtinghu Lake basin are used to investigate the variability and tendency of extreme rainfall with Mann-Kendall test technique and moving t-test.The results show that the trends of extreme precipitation indices are largely different;the trends are not significant and it do not pass the confidence level test;extraordinary wet weather and extreme wet weather in northwest and southeast stations appear the ascending trend;the numbers of rainy day in north stations appear the ascending trend;the daily maximum precipitation in most stations appear the ascending trend;the sudden change of index year mainly concentrate on the late of the 20th century and it obviously decreases after 2001;the number of stations of sudden decreased year is obviously more than that of sudden increased year.