Validation of Millimeter‐wave Atmospheric Sounder (MAS) ozone measurements

Abstract

This paper discusses the validation of measurements of O3 distribution in the Earth's atmosphere made by the Millimeter‐wave Atmospheric Sounder (MAS), a component of NASA's ATLAS spacelab shuttle package. Measurements of 184 GHz O3 emission from the Earth's limb at tangent altitudes between 20 and 80 km were made with a 50 channel radiometer having a spectral resolution of 200 KHz. In three missions the emissions of O3, H2O, ClO, and O2 were measured between 70°S and 70°N latitudes. O3 mixing ratio calculations and error analysis were performed with the Rodgers optimal estimation method. Data binned in 128 s batches yield mixing ratio profiles with an altitude resolution of 7 km at the O3 peak and an estimated accuracy of 5%. Additional retrievals made with all data from each mission binned in 5° latitude zones yield mixing ratios with about 5 km altitude resolution and somewhat improved accuracy. Comparisons with coincident measurements from other space platforms indicate a general agreement within approximately 5%. The data are publicly available through the German Remote Sensing Data Center.