Abstract: Based on meteorological and hydrological data, the temporal and spatial distribution of the rainfall during the flood period in the years of 1954,1991 and 2003 over Huaihe River basin was analyzed, flood-causing torrential rain process and meteorological cause were studied as well. The results show that the length of Meiyu (plum rain) period is closely related with the position of the ridge line of the subtropical high(along 120oE) and stability blocking high formed in the middle and supper latitude over Eurasia. The heavy rain during Meiyu period results from the combination of multi-weather systems. It was also found that the flood over the Huaihe River basin was mainly caused by the storm of the long period, high intensity and large area. The flood over Huaihe River basin in 2003, the largest one since 1954, resulted from the concentrated and frequent storms, the discharge through the Hongzehu outlets was the largest one for the past 50 years and the discharges through Wangjiaba, Runheji, Lutaizi, Bengbu and Sanhe Gate were larger than those in 1954 and 1991.
Keywords: Flood-causing torrential rain synoptic system feature of flood
1. Introduction
2. The precipitation of 1954,1991 and 2003
3. The reasons of flood-causing torrential rain
4. Analysis of the flood in 1954,1991 and 2003
5. Discussion and Summary