A method for estimating the land surface temperature from satellite data using emissivity derived from vegetation index

摘要

In the studies related to land surface processes, Stefan-Boltzmann type relation provides tool for estimating surface temperature from the knowledge of surface brightness temperature and surface emissivity, The parameters used in such relation are temperature dependent and should be treated with care. In the study undertaken over the East Godavari District Andhra Pradesh (Tropical), the temperature dependence of these parameters has been taken in the range of 298-310 K, The present methodology utilizes satellite data in determining the surface emissivity over partially vegetated heterogeneous areas by taking NDVI as a modulating parameter at satellite pixel resolution. The methodology is based on the calculation of fraction of vegetation cover per pixel from NDVI and reflectances of pure pixels derived from satellite data as input for determining surface emissivity, In the study, emissivity values derived from satellite have been used in Stefan-Boltzmann relation for estimating surface temperature. The derived surface temperature values have been compared with the meteorological data over the region and are found to be in conformation. Further, the results obtained have been compared with the modified Stefan's equation suggested in literature and are found to be in good agreement with the difference of values less than 1 It. The study suggests that Stefan-Boltzmann relation can be used for deriving surface temperature over tropical areas. [References: 26]