Study On Modle Of The Medium-term And Long-term Hydrology Runoff Forcasting Upwards Hongze Lake

Huaihe River is one of the seven greatest Rivers in China. Hongze Lake is located in the middle reaches terminal of Huaihe main stream, Accepting water come from the upper and middle reaches with 158,000 km~2 drainage area. It is a key project for regulating middle and lower reaches water volume. Hongze Lake not only takes on flood-control duty in the lower reach of Huaihe River, but also becomes the largest storage reservoir of north region in Jiangshu province. The storage volume directly affects the water supply for north region in Anhui province. As one of the important non-project means, the medium-term and long-term runoff forecasting need developed necessarily and urgently. The paper makes some research on this issue, and gains some cheering results.The medium-term and long-term runoff forecasting is the technical way to forecast the future daily or ten-days runoff process according to the preceding condition of research basin, the input runoff process of forecasting cross section and relevant hydrometeorology factors, through statistic and analytic methods and physical genetic analyzing.At present, the practicable medium-term and long-term hydrology forecasting method is a multi-statistic forecasting technique based on preceding circumfluence analysis, sea temperature character analysis and hydrology elements analysis about forecasting basin.The paper adopts the multi-statistic forecasting method to forecast input runoff of ten-days and month which depends on the hydrometeorology character of the basin upwards the Hongze Lake. The statistic forecasting method involves many methods and models including the gradually optimizing method, stable ARMA (p, q) model, linear dynamic system model, meteorology factors method and so on. After forecasting through statistic forecasting method, we can decide the forecasting results' weight of each method through simulating precision, and weighted average every method's forecasting result, then, we can get a synthetical and relatively reasonable forecasting result. The paper selects three factors the sea temperature of northern Pacific Ocean, the 500hpa and 100hpa air pressure on northern hemisphere as the meteorology factors, and uses statistic forecasting method to forecast the input runoff volume on the basin upwards the Hongze lake. Good effect are gained on forecasting the input runoff volume of 2002 and 2003 through introducing into the forecasting functions build in this paper and the forecasting results can be referenced in actual work.