Modelling Regional Actual Evapotranspiration Using Satellite Data

Knowledge of evapotranspiration defined as the ratio between actual evaporation to available energy, is a key component in studies related to water and energy balances on the Earth's surface. In the last two decades many models have been developed to estimate evapotranspiration for a wide range of patial and temporal scales, and surface conditions. Availability of land surface variables at large spatial scales from remote sensing has led to development of approaches that permit mapping of potential and actual ET at river basin scales. In particular, data products from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensors onboard the EOS-Terra and EOS-Aqua satellites, are extremely popular in regional evapotranspiration mapping studies.The present study was taken up to map the daily actual evapotranspiration over the Netravathi river basin using MODIS data. This river basin extending over an area of 3314.43 km2 is located in the humid tropical region of coastal Karnataka State, India.