RETRIEVAL OF STRATOSPHERIC TEMPERATURES FROM SPACEBORNE MICROWAVE LIMB SOUNDING MEASUREMENTS

Microwave limb sounding is a well-suited technique for the observation of the composition and temperature of the middle atmosphere. The Shut tle-borne millimeter-wave atmospheric sounder (MAS) measures three oxy gen lines in the 61-64 GHz region. Since oxygen is uniformly mixed in the lower and middle atmosphere, the amplitude and shape of the emissi on lines depend only on temperature and pressure. From these oxygen em ission lines, vertical temperature profiles are retrieved with a verti cal resolution of 5 km in the altitude region of 15-45 km (127-1.5 hPa ). The estimated total error is 1.5 K at altitudes of 25-35 km (24.5-5 .7 hPa) and up to 5 K above and below this region. Simultaneously with the temperature profile, certain instrument parameters are retrieved. We present the first MAS temperature retrieval results taken at three different locations from measurements of March 31, 1992, during the A TLAS 1 mission. The temperature retrieval results are basically in goo d agreement with National Center for Environmental Prediction (NCEP) a nalysis data, but the MAS retrievals have a tendency to low temperatur es in the lower stratosphere.