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ENVISAT / SCIAMACHY Validation with the LPMA / DOAS Balloon Gondola: Comparison of O3, NO2 and BrO Profiles

Sebastian Kreycy(1), Marcel Dorf(1), Alexei Rozanov(2), André Butz(3), Christian von Savigny(2), Claude Camy-Peyret(4), Martyn P. Chipperfield(5), Katja Grunow(6), Lena Kritten(1), Cristina Prados-Ramón(1), John P. Burrows(2) and Klaus Pfeilsticker(1)

(1) University Heidelberg, INF 229, 69120 Heidelberg, Germany
(2) University Bremen, Otto-Hahn-Allee1, 28359 Bremen, Germany
(3) SRON, Sorbonnelaan 2, 3584 CA Utrecht, Netherlands
(4) Université Pierre et Marie Curie, 4 place Jussieu, F-75252 Paris, France
(5) University of Leeds, LS2 9JT, LS2 9JT Leeds, United Kingdom
(6) University Berlin, Carl-Heinrich-Becker-Weg 6-10, 12165 Berlin, Germany

Abstract

In the past years 5 stratospheric balloon flights were performed with the LPMA / DOAS (Limb Profile Monitor of the Atmosphere / Differential Optical Absorption Spectroscopy) balloon gondola at low, mid and high-latitudes with the aim to validate EnviSat / SCIAMACHY Level 1 and 2 products. The instruments of the LPMA / DOAS gondola allow to perform solar occultation measurements in the UV/vis/near IR spectral range from which vertical profiles of O3, NO, NO2, HNO3, BrO, ClONO2, OClO, HCl, IO, OIO and of some other (source) gases (N2O and CH4) can be inferred simultaneously. Although balloon flights and EnviSat overpasses are tightly coordinated, the remaining temporal and spatial mismatches of both sets of measurements require corrections by detailed investigation of the probed air masses and their photochemical evolution. Therefore, photochemical changes are calculated along air mass trajectories which match the balloon with the satellite observations. DOAS profiles are then used to validate O3, NO2 and BrO SCIAMACHY limb profiles from scientific and operational retrievals. Additionally a UV/vis mini-DOAS spectrometer was deployed during all validation flights measuring skylight radiances, trace gases in fixed limb and scanning limb geometry, which allow the construction of time dependent fields of the studied radical species. It thus provides a stringent test for the involved RT modelling of our optical measurements, and a direct cross validation of the trace gas profiles measured by the balloon gondola and the satellite. The present paper reports on a) the involved methods b) validation results and c) scientific implications of our observations.