An empirical approach to retrieve Evapotranspiration over Amazonia

The estimation of regional evapotranspiration (ET) over Amazonia remains uncertain since there are very few in situ observational with a limited footprint (~1km). The present work uses an empirical method to estimate ET over the Brazilian Legal Amazon (BLA) based on satellite measurements. Satellite data include the Enhanced Vegetation Index (EVI) from the Moderate Resolution Imagining Spectroradiometer (MODIS) and the surface radiation budget from the International Satellite Cloud Climatology Project (ISCCP) for the period (2000-2004). The empirical model was calibrated (2 sites) and validated (6 sites) using observational measurements in the BLA. Results from F-test and t-student test have shown that observed and calculated ET have the same variance and mean values, respectively.