基于MODIS数据的沙漠化地区地表宽波段反照率的反演方法研究--以新疆地区为例

Land surface albedo, w hich is a fundamental component needed for determining the radiation balance of the Earth atmosphere system , is the surface hemispherical reflectivity integrated over the solar spectrum.Briefly said, it is the ratio of the total upwelling irradiance to the total down ward irradiance. Given the limit of experiment field and instrument equipment, it is very difficult to obtain a great deal of surface measured data.Thereof, in our research, from the point of view that surface albedos are the ratio of flux, surface albedos can be reversed w ith less calibrated field synch ronous observed data. the third is to calculate surface broadband albedos, w hich is focused on determ ining the converting coefficients from narrow bands to broadbands under the the linear relation ship between narrow band albedos and broadband albedos. The spectral distribution of solar irradiance at the surface is set as the weigh ting function for comverting the narrow band albedos to broadband albedos in the research. The conversion of broadband albedos is fulfilled finally. The simplified surface broadband albedo reverse model is tested for the regions of Xinjiang province usingMODIS image data and synchronous observed surface spectral data based on the above conversion algorithm. The results show that themethod is convenient and feasible under a specific surface/atmospheric condition.