区域蒸散发分布式模拟及其遥感验证

Distributed simulation for regional evapotranspiration and verification by using remote sensing

随着遥感技术和水文模型集成技术的进步,在区域上进行蒸散发(ET)模拟和验证成为可能。为了探讨如何基于遥感监测ET进行正确的蒸散发模拟,使用1km分辨率遥感监测ET对SWAT2000模型所模拟的漳卫南运河流域主要农业耕作区实际ET进行了率定分析,并探讨了SWAT模型农业耕作措施设置以及土壤和作物生长参数的合理取值问题。结果表明,SWAT模型模拟ET与遥感监测ET的确定性系数R2和Nash-Sutcliffe效率系数ENS分别达到了0.93和0.92;土壤蒸发与作物蒸腾的比例受土壤蒸发补偿系数(ESCO)影响较大,对于冬小麦-夏玉米轮作区,ESCO取值建议在0.8～1.0之间。利用遥感监测ET数据有助于蒸散发的正确模拟,从而有效地提高水文过程的模拟精度。

Regional evapotranspiration （ET） in river basins, one of the most important hydrological processes, was usually unable to be estimated efficiently due to the lack of reliable observed data. Recently, with the development of remote sensing （RS） technology and hydrological model integration, it becomes possible to estimate ET at regional scale. Remote sensing derived ET （1 km-resolution）, which was derived from MODIS satellite data by the institute of remote sensing and application （IRSA） of CAS, was applied to validate the monthly ET simulated by using soil and water assessment tool （SWAT） in the Zhangweinan River basin. Agricultural management practices and parameters for crop growth were then calibrated and analyzed. The calibrated and validated results showed that ET was sensitive to both crop parameters and the soil evaporation compensation coefficient （ESCO, its value was suggested to range from 0.8 to 1.0 for the crop land of winter wheat-summer corn）. Simulation had been improved greatly by using remote sensing derived ET. The coefficient of determination R2 reached 0.93, and Nash-Sutcliffe efficiency coefficient reached 0.92. Regional ET simulation and then the hydrological modeling were greatly improved by using remote sensing derived ET.