鄱阳湖流域1955-2002年径流系数变化趋势及其与气候因子的关系

Runoff coefficients change and the analysis of the relationship between climate factors and runoff coefficients in Poyang Lake Basin (China):1955-2002

研究了鄱阳湖流域在1955-2002年间的径流系数的变化,重点分析了它与水循环的两个基本要素:降水量和蒸发量的关系,同时对其原因进行了初步的探讨,经分析,在鄱阳湖流域中,径流系数较大的是饶河流域和信江流域,较小的是抚河流域;在年内变化上,4-6月为五河流域径流系数比较大的月份,这与鄱阳湖流域降水集中期相对应．在空间上,4 -6月仍然以饶河流域和信江流域相对较大,而抚河流域较小,特别是8月份的径流系数远小于其他四河;年代际变化上, 1990s径流系数增加较为显著．尽管鄱阳湖流域的径流系数除了受气候因子的影响外,还受到水土流失和地形等因素的影响,但是降水量的增加,特别是暴雨频率的增加仍然是其主要影响因素,蒸发量的减小对径流系数的增加也有一定程度的影响．径流系数与气温并无明显的线性相关关系．

From the view of water cycling, runoff coefficients are important index of water resources in a particular catchment. Changes of runoff coefficents in the five rivers of Lake Poyang basin 1955 - 2002 were analysed. Result shows that runoff coefficients of Raohe River basin and Xinjiang River basin are the highest, while of Fuhe River basin is the lowest. As for monthly change, that of the five river basins all have reached the higher value from April to June, which corresponds to the rainfall period of Poyang Lake basin. Moreover, In August, runoff coefficient of Fuhe River basin is far lower than the four others. In the 1990s, runoff coefficients of the five river basins increased significantly. Although the runoff coefficients would be impacted by soil erosion and topographic condition, change of precipitation is a main factor to runoff coefficients. Downward trend of evapotranspiration also impacts on increasing runoff coefficients. Especially in the 1990s, the increase of runoff coefficients is closely related to the increase in rainstorm frequency and decrease in evapotranspiration. The relationship between temperature and runoff coefficients is not much significant.