分布式模型在流域蒸散模拟中的应用与验证

Application and verification of distributed model in simulating watershed evapotranspiration.

根据四川杂谷脑河流域上游地区1989-2000年气象站常规观测数据，应用分布式模型方法，考虑流域的空间异质性及时空变异性，选择离散单元格尺度为500m，时间步长为1d．采用Penman-Monteith公式的改进形式，估算流域多年平均潜在蒸散量的时空分布；结合流域下垫面特点，估算逐日实际蒸散量的时空分布；并将模型模拟的多年平均值与研究区同期水量平衡法计算结果相比，相对误差为＋3．47％且时空分布合理．为流域分布式降雨．径流模型提供了可靠的实际蒸散量模拟方法。

Based on the conventional observed meteorological data during 1989-2000, a distributed model was employed to simulate the temporal and spatial distribution of the potential and actual evapotranspiration in the upper Zagunao watershed of Sichuan Province. Grids of 500 m and step of 1 d were used to describe the spatial and temporal heterogeneity and variability in the study area. The potential evapotranspiration was simulated by a deformation form of Penman-Monteith Equation, and a method for calculating actual evapotranspiration was proposed, with the underlying conditions considered. The results showed that the relative error of the normal annual evapotranspiration in the 12 years between the simulation and the calculation was 3.47 %, with a reasonable temporal and spatial distribution. The research results provided an effective method for the distributed rainfall-runoff model in simulating actual evapotranspiration.