SPATIOTEMPORAL VARIABILITY OF EVAPOTRANSPIRATION IN PANTANAL, BRAZIL, USING SATELLITE IMAGES

Resumo

Despite the importance of evapotranspiration (ET) for the Pantanal, there are few studies about it. In this study we aim to estimate evapotranspiration in Pantanal by applying a spectral-agrometeorological model SAFER (Simple Algorithm for Retrieving Evapotranspiration) using satellite images and data from meteorological stations to analyze spatiotemporal variability of ET biome´s. We used 46 images taken by MODIS (Moderate Resolution Imaging Spectroradiometer) satellite, with a 250 m spatial resolution and a 16-day resolution time, covering rainy (October 2011 to March 2012) and dry (April to September 2012) periods. The SAFER model was effective to estimate ET large scale for rainy and dry season and was sensitive to variations observed in the land use class as well as the relation with the air temperature, solar radiation and rainfall. The highest values of ET were observed in the rainy season, due to the higher availability of water because of rainfall and higher incidence of solar radiation, and the smaller ET values were observed in the dry season