Climatic Variations of Dryness and Wetness in Sichuan Basin during 1955-2009

According to the climate data(precipitation and temperature) of 18 meteorological stations in Sichuan Basin from 1955 to 2009,the relative moisture index is calculated,and the variations of dryness and wetness in the basin in the recent 55 years are analyzed with Climate Trend Coefficient and Mann-Kendall test.The results of the study show that,spatially,the variation of climate changes is characterized by a transition from dryness to wetness from west to east in Sichuan Basin,but the difference is not significant and,temporarily,the dryness or wetness in Sichuan Basin is steady,except for that in Leshan,Mianyang,Chengdu and Yibin the climate showed a significant tendency to dryness from 1960s,and there were sudden changes in 1966,1993,1997 and 2001.Oppositely,the climate in Dazhou and Shapingba became significantly wetter in this period.The climate change of dryness and wetness in Sichuan Basin is primarily influenced by the two meteorological factors of regional precipitation and sunshine hours.