Abstract:

Preferably estimating runoff of the Three Gorges Reservoir (TGR) area in September is important to safely and effectively achieve the pondage mission of TGR. Using correlation analysis, it found that there was a significant positive correlation between runoff of TGR area in September and precipitation in most meteorological stations which located in upstream of the Yangtze River Valley (YRV) in August. According this, we define the key region of anterior precipitation in upstream of the YRV for influencing runoff of TGR area. Calculating the arithmetic mean value of precipitation in the meteorological stations which located in the key region in August and comparing the interannual changes of the mean precipitation and runoff of TGR area in September, it found that they changed in accordance and had a significant positive correlation. So the precipitation of the key region in August can act as an important factor to estimate runoff of TGR area in September. This result can provide some references to make the pondage plan of TGR. We also analyze the relevant background of atmospheric circulation, and found that the amount of runoff of TGR area tightly correlated with the variation of atmospheric circulation, i.e., in the low value years of runoff of TGR area, the synoptic situation and water vapor transportation are disadvantaged to occurring of precipitation process, and then it can cause the low runoff of TGR area in posterior, and vice versa.