全国二级流域实际蒸散分布式模型

Distributed Model of Actual Evapotranspiration in Nationwide Secondary River Basins

[目的]研究全国二级流域实际蒸散分布式模型,为估算流域实际蒸散提供可靠的依据。[方法]基于研究区1956—1979年的水文、气象数据,运用水量平衡方程和蒸散互补相关理论,提出了改进的流域实际蒸散的通用模型。[结果](1)全国二级流域多年平均实际蒸散发量的空间总体分布具有明显的地带性特征;(2)湿润区和半湿润区的流域实际蒸散与可能蒸散的趋势线有明显的闭合趋势,干旱区和半干旱区流域的实际蒸散与可能蒸散的趋势线之间距离较大,但仍呈现闭合趋势;(3)全国77个二级流域实际蒸散通用模型的模拟误差均在10%以内。[结论]不同二级流域实际蒸散与可能蒸散的互补关系明显存在,改进的通用模型提高了估算流域实际蒸散的精度。

[Objective]Studying the distributed model of actual evapotranspiration in nationwide secondary river basins in order to provide the reliable basis for estimating basin actual evapotranspiration.[Methods]Based on the climatic and hydrological data during 1956 and 1979,the water balance method and the evapotranspiration complementary theory were used to propose the general model for improving the actual evapotranspiration of the river basin.[Results]（1）According to the actual evapotranspiration of many years,the spatial distribution had obvious zonal characteristics.（2）The trend line between the actual evapotranspiration and potential evapotranspiration had nearly overlapped over the humid areas and sub-humid areas basin.The distance between the trend lines of arid and semi-arid basins was relative large,but it still show a tendency to be closed.（3）The error simulated by hydrological and meteorological data of 77 secondary river basins was small than 10%.[Conclusion]Under different climatic conditions,the complementary link between actual and potential evapotranspiration clearly exists.The improved general model could be used to improve the estimating accuracy of actual evapotranspiration in the basin.