Abstract:

Based on the daily precipitation data of the Huaihe River Basin ground stations during 1958~2007 for 50 years,the law of spatialtemporal distribution of the Huaihe River Basin rainfall and its fluctuations were studied by precipitation anomaly percentage and linear trend method and the Morlet wavelet analysis.The results indicated that rainstorm days of the Huaihe River Basin showed three stages.Two growth for the heavy rain days were during 1958~1964 and 1994~2007.The shortage of heavy rain days was during 1965~1993 with most of the year about the positive and negative anomalies 1 to 2 years alternately.Torrential rain days of the Huaihe River Basin in the 21st century significantly increased.There were 13 years in which the storm rainfall of June to August was on the high level in the Huaihe River Basin. From the 1980s,more frequent floods occurred,particularly after 2000,the rainfall increased significantly.Morlet wavelet timefrequency variation study indicated that the Huaihe River Basin showed some periodic time series,and 2,5,15,27 were the important cyclical timing.North part and south part of the Huaihe River showed different storm trends.South part of the Huaihe River was the center of the rainfall area,and the tendency of the south part being more rainfall and the north part being less rainfall was more and more intensified