Retrieval of Latent Heat Flux from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Images in South-Western Amazonia

Currently there is a great concern about tropical deforestation and its influence on climate, particularly in the Amazon region. Micrometeorological experiments have been conducted involving the collection of continuous data in Amazonia. However, field measurements are usually localized and given the extent of this region it is necessary to represent spatially the surface energy fluxes under a broader scale. The present study aimed to estimate the latent heat flux under different land use and land cover types (old-growth forest, secondary succession forest, pasture, rough pasture, bare soil and water bodies), using data from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) through the Surface Energy Balance Algorithms for Land (SEBAL) model, for an area located in the municipality of Ouro Preto do Oeste, Rondônia state, Brazilian Amazon. To run the SEBAL model, air temperature and wind speed data, acquired by a micrometeorological tower of Large-Scale Biosphere-Atmosphere Experiment in Amazonia (LBA) project located within the study area, and ASTER reflectance and surface temperature products were used. The latent heat flux estimates were in agreement with values from other studies using orbital data in similar land use and land cover types. In addition, latent heat flux values obtained for homogeneous areas of old-growth forest and pasture were consistent with micrometeorological studies carried out under these conditions in the Amazon region. The proposed methodology may work as an alternative approach for researches related to the land surface-atmosphere interaction in this region.