Evapotranspiration, a major component in terrestrial water balance and net primary productivity models, is difficult to
measure and predict. Remote sensing cannot provide a direct measurement of evapotranspiration (ET) but it can provide
a reasonably good estimate of Evaporative Fraction (EF), defined as the ratio of ET and available energy. Recent studies
have successfully estimated EF using a contextual interpretation of radiometric surface temperature (T0) and normalized
difference vegetation index (NDVI) such as from the Advanced Very High Resolution Radiometer (AVHRR) onboard
NOAA-14 satellite and Moderate Resolution Imaging Spectroradiometer (MODIS), onboard EOS Terra satellite,
sensors to estimate ET over large areas. This study compares AET from MODIS and AVHRR applied to a mountainous
river basin in Indian Himalayas. Surface Energy Balance (SEBAL) has been used for estimating Actual
Evapotranspiration (AET) in the region. In this paper, remote sensing data are used to evaluate the surface albedo, net
radiation, ground heat flux, sensible to estimate evapotranspiration and surface conditions using energy balance
approach. Being a mountainous basin, an attempt has been made to consider terrain effects in estimating net radiations.
Results showed that AVHRR gives an average value whereas MODIS data gives better results since resolution of
MODIS is better than that of AVHRR.