RETRIEVAL OF STRATOSPHERIC O3, HNO3 AND CLONO2 PROFILES FROM 1992 MIPAS-B LIMB EMISSION-SPECTRA - METHOD, RESULTS, AND ERROR ANALYSIS

Within the framework of the European Arctic Stratospheric Ozone Experi ment, two flights of the balloon-borne MIPAS-B limb emission spectrome ter were performed in the Arctic stratosphere from Kiruna, northern Sw eden. During the early hours of January 13 and the night from March 14 to March 15, 1992, several limb sequences of infrared spectra were re corded which have permitted the retrieval of vertical profiles of many trace gases relevant for ozone chemistry. In the present work, the re trieval strategy, error estimation strategy, and resulting profiles Of O3, HNO3, and ClONO2 are reported. The data analysis procedure, consi sting of data preprocessing including calibration, analysis of auxilia ry data including temperature profiles and line of sight determination , and retrieval of trace gas profiles, is described in detail. The las t is carried out by means of multiparameter nonlinear least squares fi tting in combination with onion peeling. An astonishingly high ClONO2 amount of 2.6 ppb by volume at about 19-km altitude was inferred for t he March flight. A rigorous error analysis, which takes into account s ystematic and random errors and their often nonlinear impact on the re sults, proves the significance of the retrieved trace gas profiles.