Sea‐surface emissivity parametrization from microwaves to millimetre waves

Abstract

In preparation for new observations on board the next generation of the European operational meteorological satellite (EUMETSAT Polar System—Second Generation (EPS‐SG)), a parametrization of the sea‐surface emissivity is proposed from 10–700 GHz: Tool to Estimate Sea‐Surface Emissivity from Microwaves to sub‐Millimeter waves (TESSEM2). It is based on the community model FAST microwave Emissivity Model (FASTEM) at frequencies up to 200 GHz, where FASTEM has been calibrated and validated operationally. It follows a physical emissivity model at higher frequencies. A preliminary evaluation of TESSEM2 has been conducted with success, by comparison with airborne International Sub‐Millimetre Airborne Radiometer (ISMAR) observations from 118–325 GHz, under low wind speed (3–5 m s−1) off the coast of Scotland. TESSEM2 is a fast parametrization that can easily be implemented in a community radiative transfer model. The code is available to the community and will be distributed with the next version of Radiative Transfer for the TIROS Operational Vertical Sounder (RTTOV).