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ETWatch是用于流域蒸散遥感监测、针对遥感应用而设计的集成框架。方法集成了具有不同应用优势的遥感蒸散模型,并以Penman-Monteith方法为基础建立时间扩展方法,利用气象数据与晴好日的通量遥感估算结果,获得逐日连续的蒸散分布图。所生成的从流域级到地块级的数据产品能动态反映区域蒸散发的时空变化规律。为深入了解遥感蒸散量估算中的不确定因素,本文将其通量计算过程分为地表温度、地气温差、短波与长波辐射、水体热通量、显热通量等环节与地面数据进行对比和逐项的标定。利用站点地面观测资料对模型输入的蒸发比的比较表明参数标定可有效提高遥感与地面蒸散观测的吻合程度。
ETWatch is an integrated framework designed for remote sensing of watershed evapotranspiration for remote sensing applications. The method integrates the remote sensing evapotranspiration model with different application advantages and establishes the time extension method based on the Penman-Monteith method. The daily evapotranspiration distribution map is obtained by using the meteorological data and the flux estimation data of the good day. The generated data products from watershed level to land-based level can dynamically reflect the spatial and temporal variation of regional evapotranspiration. In order to deeply understand the uncertainties in the estimation of evapotranspiration, this paper divides the calculation of fluxes into surface temperature, ground temperature difference, short-wave and long-wave radiation, water body heat flux and sensible heat flux, etc. And itemized calibration. The comparison of the evaporation ratio of the model inputs using the site ground observation data shows that parameter calibration can effectively improve the agreement between remote sensing and ground-based evapotranspiration observations.