A rapid radiative transfer model for SSMIS UAS channels that takes the earth-rotation doppler shift and Zeeman effects into account

Special Sensor Microwave Imager/Sounder (SSMIS) on board the US Defense Meteorology Satellite Program (DMSP) satellites includes six upper atmosphere sounding (UAS) channels. Radiances in three of the UAS channels, channels 19 - 21, are influenced by a combination of Doppler shift caused by Earth's rotation and the effect of the Zeeman-splitting of the O2 magnetic transition. In order to operationally assimilate the radiance data or retrieve temperature profile from the data, a fast radiative transfer (RT) model for the SSMIS UAS channels has been developed and recently implemented in the Community Ratiative Transfer Model (CRTM). This paper provides a summary of the model algorithms and validations. Also included in the paper are the preliminary results of temperature profile retrieval from a one-dimensional variational system in which the fast model is applied.