Resemblance of Quikscat radar backscatter and differential emissivity of land surface derived using TRMM TMI through radiative transfer model

摘要

Interpretation of microwave radiometric measurements over land for atmospheric studies requires representative information about surface emissivity. A simulation study has been performed to derive some of the meteorological parameters like atmospheric water vapour content over land using TRMM TMI data through assumed land surface emissivity satisfying the radiative transfer model. The process of minimization of simulated and observed radiation at TMI frequencies using a large number of simulated atmospheric and surface conditions simultaneously yields many atmospheric and surface parameters over land. Preliminary analysis of TRMM TMI data over India and adjoining land region for few days during different season has been carried out. The derived surface emissivity difference of vertical and horizontal polarization is found highly resembling with Quikscat radar backscatter of land surface over the same area corroborating the estimation of land surface emissivity parameters. The study has importance in synergic use of microwave radiometer and scatterometer for studying the surface features as well as retrieval of geophysical parameters over land in view of forthcoming Megha-Tropiques and Oceansat-2 satellites. Typical examples of TRMM-TMI and Quikscat scatterometer are presented here.