Atmospheric correction of Landsat TM imagery for evapotranspiration estimation in the lower Colorado River basin

摘要

Atmospheric correction for remotely sensed data is an essential process for accurate estimation of evapotranspiration (ET), which assists in understanding the evapotranspiration rate of riparian vegetation and the management of water resources in the Lower Colorado River basin. A comparative study of atmospheric correction was conducted for Landsat Thematic Mapper (TM) imagery using Second Simulation of a Satellite Signal in the Solar Spectrum (6S) and ENVI's Fast Line-of-sight Atmospheric Analysis of Spectral Hypercubes (FLAASH) algorithms. 6S, a vector version of the radiative transfer code, takes into consideration the radiation polarization to compensate atmospheric absorption and scattering effects, while FLAASH is a M0DTRAN4+ radiation transfer code solution. After the atmospheric correction, the surface reflectance values will be correlated with ground and helicopter spectroradiometer measurement to assess the atmospheric correction and thereby to provide useful information for the subsequent evapotranspiration calculation.