基于HASM方法的黑河流域潜在蒸发量的模拟

Simulation of Potential Evapotranspiration in Heihe River Basin Based on HASM

潜在蒸发作为研究蒸发及区域水循环的重要因素之一,其模拟结果对相关领域的研究应用具有重要影响。利用2000-2009年"黑河流域每日四次常规气象观测数据集"所提供的12个气象站点的潜在蒸发数据,对黑河流域潜在蒸发量进行模拟。首先针对潜在蒸发的特点,分析影响研究区域潜在蒸发的气象因素、地理及地形因素,使用多项式回归和逐步回归的方法对研究区域潜在蒸发进行了背景趋势模拟,选出影响潜在蒸发的最优影响因素组合,在此基础上采用高精度曲面建模(HASM)方法,结合站点实测数据,对去掉趋势后的残差进行精度修正。本文使用kriging法、IDW法和Spline法插值所得潜在蒸发数据,以及"黑河流域1980-2010年3 km 6 h模拟气象强迫数据"作为对照,比较验证模拟精度。模拟结果表明:HASM方法模拟精度最高,模拟结果分布合理,表明该方法在潜在蒸发模拟中具有应用前景。该方法所得到的潜在蒸发数据可作为基础地理数据供相关研究应用。

Potential Evapotranspiration （PET） is one of the important factors in the study of evapotranspiration （ET） and local water resources. Accurate PET dataset is crucial for improving our understanding of basin-scale hydrology, agriculture and earth sciences. In this study, ET data measured at 12 stations during the period of 2000-2009 were used to simulate the PET in Heihe River Basin by using a new surface modeling method, so called High Accuracy and high Speed Method （HASM）, which has been successfully used in the construction of Digital Elevation Model （DEM） and the studies of ecosystem changes. The relationship between PET and climatically/topographical variables was explored, and a polynomial regression model for PET was developed. The stepwise regression method was used to find an optimal subset of influence factors for PET. Finally, polynomial regression and residual interpolation using HASM were employed to develop a gridded ET dataset for Heihe River Basin. The simulation results of our method were compared with other potential evapotranspiration datasets including the ＂Simulated forcing dataset of 3km/6 hour in 1980-2010 in Heihe River Basin＂ and the interpolation results by using Kriging, IDW and Spline. Results showed that HASM exhibited good performance in ET simulation. Accuracy tests revealed that HASM was superior to other datasets. Therefore, HASM can be considered as an alternative and accurate method for PET interpolation in Heihe River Basin. As the basic geographical data, PET produced by HASM can be used for other applications.