Modelo físico-matemático de correção atmosférica para imagens TM-Landsat 5 e Modis Terra/Aqua.

Abstract

In this work a model named ME is presented for atmospheric correction of TMLandsat 5 and MODIS-Terra/Aqua images. This model improves the estimation of temperature and reflectance of Lambertian surfaces evaluated by METRIC algorithm under clear sky conditions. ME is based on the radiation propagation in the atmosphere using the two-stream method in the solar spectrum and a simplified solution of the Schwarzchild equation in the wavelength of 10,4 to 12,5 μm. The scattering process is described in an atmosphere subdivided into 16 layers using a stochastic structure. The proposed model estimates precisely the transmittance and the irradiance global at the surface with an error less than SBDART, and allows establishing the necessary functions for a good correction of atmospheric effects contained in the surface parameters stored by satellites. The transmittance and the thermal radiation of the atmosphere are obtained by means of parameterizations avoiding the use of radiosonde data. In order to estimate the surface temperature (Ts) with TM-Landsat 5 images a mono-window used and a split-window for the MODIS images. In the estimation of the surface reflectance (Rs) with TM-Landsat 5 images the proposed model presents an error between 1,5 and 5% in relation to the measured values, while METRIC presents an error between -10% and 11%. The ME efficiency is the same with MODIS and TM-Landsat 5 images. In places with high aerosol load, METRIC presents errors above 50%, while ME presents error under 15%. The estimation error for Ts is less than 1,8 K (with TM-Landsat 5 and MODIS images). The results show that ME is efficient in the process of atmospheric correction in the atmospheric window and in the solar spectrum in places with high and low aerosol loads.