Assessment and Adaptive Correction of Observations in Atmospheric Sounding Channels of the Satellite Microwave Radiometer MTVZA-GY

The microwave radiometer MTVZA-GY on board the Russian polar orbiting meteorological satellite Meteor-M N2 is briefly described. Errors and biases in antenna brightness temperatures are documented. Observation errors are found to be dependent on the solar angles. An adaptive bias correction technique for MTVZA-GY antenna temperatures is motivated and developed. The technique accounts for the solar angles and sequentially assimilates observed minus simulated radiances in a perpetual 24 h cycle in order to estimate up-to-date correction coefficients defined to be functions of the zenith and azimuth solar angles. The simulated radiances are computed by the RTTOV radiative transfer model from three-dimensional numerical weather prediction fields. The correction technique is implemented for atmospheric temperature and humidity sounding channels of MTVZA-GY. The corrected observations are shown to be significantly more accurate as compared with raw antenna temperatures and with observations that undergo simpler and more traditional corrections. The accuracy of corrected MTVZA-GY observations is compared with the accuracy of AMSU-A and MHS data.