Operational calibration of a fully polarimetric radiometer for stratospheric temperature retrievals

Abstract. The oxygen emission band at 60 GHz is a commonly used frequency band for atmospheric temperature sounding. The oxygen fine structure emission lines used for retrievals of the temperature in the stratosphere and mesosphere are affected by the Zeeman effect which has a characteristic influence on the spectral shape of different polarization states. As a consequence of this effect, a V-Stokes component is generated, indicating symmetry breaking between right and left circular polarized radiation. In this study, we present the full-rank Stokes vector of the fine structure emission lines at 53.067 GHz and 53.596 GHz, measured with a fully polarimetric radiometer. We discuss the advantages of the fully polarimetric approach compared to single-polarization observations for temperature sounding by comparing both simulations and observations. Finally, we present an operational calibration method and show calibrated spectra of the four components of the Stokes polarization vector and a continuous series of the retrieved temperature profiles.