AN IMPROVED METHOD FOR CALCULATING TROPOSPHERIC TEMPERATURE AND MOISTURE FROM SATELLITE RADIOMETER MEASUREMENTS

Abstract

An improved method for calculating tropospheric temperature and moisture from satellite radiometer measurements is developed. The troposphere is modeled by two temperature lapse rates and a single moisture lapse rate. These lapse rates as well as an optimum pressure level for dividing the two layers of constant lapse rate and surface temperature are calculated from three observations in the 15µ CO2 band, an observation in the rotational water vapor band, and an observation in the 11µ window region. Radiances observed by a balloon-borne interferometer were used to approximate filtered radiometer measurements. Solutions for tropospheric temperature and moisture from the approximated radiometer observations are shown to agree favorably with radiosonde observations for both clear and partly cloudy conditions. The computations required are only 10 percent of those required by a previously developed method. Abstract An improved method for calculating tropospheric temperature and moisture from satellite radiometer measurements is developed. The troposphere is modeled by two temperature lapse rates and a single moisture lapse rate. These lapse rates as well as an optimum pressure level for dividing the two layers of constant lapse rate and surface temperature are calculated from three observations in the 15µ CO2 band, an observation in the rotational water vapor band, and an observation in the 11µ window region. Radiances observed by a balloon-borne interferometer were used to approximate filtered radiometer measurements. Solutions for tropospheric temperature and moisture from the approximated radiometer observations are shown to agree favorably with radiosonde observations for both clear and partly cloudy conditions. The computations required are only 10 percent of those required by a previously developed method.