VALIDATION OF UARS MICROWAVE LIMB SOUNDER CLO MEASUREMENTS

Validation of stratospheric ClO measurements by the Microwave Limb Sou nder (MLS) on the Upper Atmosphere Research Satellite (UARS) is descri bed. Credibility of the measurements is established by (1) the consist ency of the measured ClO spectral emission line with the retrieved ClO profiles and (2) comparisons of ClO from MLS with that from correlati ve measurements by balloon-based, ground-based, and aircraft-based ins truments. Values of ''noise'' (random), ''scaling'' (multiplicative), and ''bias'' (additive) uncertainties are determined for the Version 3 data, the first version publicly released, and known artifacts in the se data are identified. Comparisons with correlative measurements indi cate agreement to within the combined uncertainties expected for MLS a nd the other measurements being compared. It is concluded that MLS Ver sion 3 ClO data, with proper consideration of the uncertainties and '' quality'' parameters produced with these data, can be used for scienti fic analyses at retrieval surfaces between 46 and 1 hPa (approximately 20-50 km in height). Future work is planned to correct known problems in the data and improve their quality.