基于遥感技术的地表蒸散业务化反演

Operational retrieving of land surface evapotranspiration based on remote sensing technology

分析地表蒸散业务化反演的现状需求及所面临的困难,从业务化运行的目标出发,根据地表蒸散业务化反演的几点原则:独立性、简洁性、普适性、尺度扩展性,对现今较为常用的几种地表蒸散模型进行对比分析,最终选取Priestley-Taylor(PT)模型作为核心方法,建立地表蒸散业务化反演的运作技术流程。在MODIS数据和气象数据支持下,以黑河流域为试验区,对该方法和流程进行验证,反演得到该流域地表日蒸散量。最后以FAO56 Penman–Monteith模型反演结果作为检验标准进行精度评价分析,两种反演结果相关性达0.880。较高的反演精度表明,PT模型的选用和该技术流程的建立是合理的,足以满足业务化反演的需求,具有进一步的可操作性和实用性。

The current situation of urgent requirement and obstacles in retrieving land surface evapotranspiration（ET） operationally were analyzed.By the comparison of the most commonly and widely used models for ET estimation,taking into account for the principles of independence,simplicity,versatility,scalability for operational retrieving,and selecting the Priestley-Taylor（PT）model as the key algorithm,,an operational technical flow-scheme was established to obtain the daily ET.With the support of MODIS data and meteorological data,taking Heihe river basin as experiment area,the model and flow-scheme were verified,and daily ET were retrieved.Evaluation of the relative accuracy of operational ET estimation flow-scheme was made by using FAO56 Penman–Monteith model supposed to be the standard model.High correlation coefficients of 0.880 were observed by these two models.Results with relatively high accuracy proved that the PT model and the flow-scheme were workable,and sufficient to satisfy the requirement of operational processing,and it was worthwhile to utilize them for the future operational ET retrieving.