三峡库区来水流量与长江流域上游前期降水的关系研究

RELATIONSHIP BETWEEN RUNOFF OF THE THREE GORGES RESERVOIR AREA AND ANTERIOR PRECIPITATION IN UPSTREAM OF THE YANGTZE RIVER VALLEY

较为准确地预估三峡库区9月份来水流量,对于安全而有效地完成三峡水库蓄水任务具有重要的实用意义。通过相关分析,发现三峡库区9月的来水流量与长江流域(Yangtze River Valley,YRV)上游大多数气象站点的8月降水量有显著的正相关,据此定义了影响三峡库区来水流量的长江流域上游前期降水关键区。计算关键区内各气象站点8月降水量的算术平均值,并对比其与三峡库区9月三峡库区来水流量的年际变化,发现两者的变化较为一致,同样具有显著的正相关关系,因此长江流域上游前期降水关键区的8月降水量可以作为预估9月三峡库区来水流量的一个重要因子,这可以为三峡水库蓄水计划的制定提供一定的参考依据。还分析了相应的大气环流背景,发现三峡库区来水流量的多少与大气环流的变化具有密切的联系,即三峡库区来水流量偏少的年份,天气形势及水汽输送等因素都不利于降水过程的发生,进而可能导致三峡库区后期的来水流量偏少;相反地,在三峡库区来水流量高值年,天气形势和水汽输送都有利于降水过程的发生,使后期三峡库区来水流量偏多。

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.