藏东南尼洋河流域降水径流水量平衡问题

为了深入分析藏东南尼洋河流域水文特征及产汇流机理,对该流域降水径流水量平衡问题进行研究。基于尼洋河流域工布江达、巴河桥、更张等水文站日降水、流量等水文气象观测资料,对采用传统泰森多边形法计算的尼洋河流域面平均雨量小于径流量这一现象进行分析,提出降雨径流水量平衡问题;针对尼洋河流域地形地貌特征、降水空间分布规律和测站分布的实际情况,提出尼洋河流域面平均雨量分布式计算方法,并进行了实例计算。计算结果表明:目前对尼洋河流域降水空间分布特征缺乏正确认识;采用传统的泰森多边形法计算面平均雨量是导致出现水量不平衡问题的主要原因。指出尼洋河流域面平均雨量计算应考虑降水的垂直分布差异。

Precipitation-runoff water balance problem in Niyang River catchment in Southeast Tibet

In order to deeply analyze the hydrological characteristics and the mechanism of runoff generation and concentration in the Niyang River catchment in Southeast Tibet, the precipitation-runoff water balance problem is examined. Based on meteorological and hydrological observation data, such as daily precipitation and flow, at Gongbujiangda, Baheqiao, Gengzhang hydrological stations etc. in the Niyang River catchment, the phenomenon of watershed average precipitation calculated with the traditional Thiessen polygons method being less than the runoff is analyzed. The precipitation-runoff water imbalance problem is described. The method and steps for distributed computing of the watershed average precipitation for the Niyang River catchment considering the topographical features, spatial distribution regularity of precipitation, and distribution of hydrological stations are proposed, and an example calculation is given. The results show that misunderstanding of the spatial distribution of precipitation in the Niyang River catchment and the calculation of watershed average precipitation with the traditional Thiessen polygons method are the main causes of the water imbalance problem. The calculation of the watershed average precipitation should consider the vertical distribution differences of precipitation in the Niyang River catchment.