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BrO Profiling from Ground-based DOAS Observations: New Tool for the ENVISAT/SCIAMACHY Validation

Francois Hendrick(1), Michel Van Roozendael(2), Martine De Maziere(1), Andreas Richter(3), Alexei Rozanov(3), Christopher Sioris(4), Sven Kuehl(5), Janis Pukite(5) and Thomas Wagner(5)

(1) Belgian Institute for Space Aeronomy (IASB-BIRA), 3, Avenue Circulaire, 1180 Brussels, Belgium
(2) Belgian Institute for Space Aeronomy (IASB-BIRA), 3, Avenue Circulaire, 1180, Belgium
(3) IUP/IFE Bremen, University of Bremen, Bremen, Germany
(4) Harvard-Smithsonian Center for Astrophysics, ?, Cambridge, United States
(5) IUP/IFE Heidelberg, University of Heidelberg, Heidelberg, Germany

Abstract

A profiling algorithm has been developed at IASB-BIRA in order to provide low vertical resolution BrO profile in the 0-37 km altitude range from ground-based zenith-sky DOAS observations. This algorithm is based on the Rodgers Optimal Estimation Method (OEM) and includes a validated forward model accounting for the transfer of the multiply scattered radiation in a pseudo-spherical atmosphere and the diurnal variation of the stratospheric BrO. It has been applied to the ground-based zenith-sky UV-visible observations continuously performed at the NDSC station of Harestua (60°N, Southern Norway) since 1998. The reliability of our BrO retrievals has been also verified through correlative comparisons with SAOZ and LPMA/DOAS balloon measurements.

Here, the time-series of stratospheric and tropospheric BrO profiles and columns retrieved at the Harestua station are used to validate limb and nadir ENVISAT/SCIAMACHY scientific products for the 2002-2004 period. Retrieval algorithms from the following groups are involved in the validation exercise: IUP/IFE Bremen, IUP/IFE Heidelberg, and Harvard Smithsonian for limb BrO profiles and, IASB-BIRA, IUP/IFE Bremen, and IUP/IFE Heidelberg for nadir BrO total columns. Comparisons between ground-based UV-visible and SCIAMACHY data are also performed in the same photochemical conditions since the profiling algorithm includes a stacked box photochemical model, enabling the retrieval of BrO profiles at any solar zenith angle.

 

Full paper

Keywords: ESA European Space Agency - Agence spatiale europeenne, observation de la terre, earth observation, satellite remote sensing, teledetection, geophysique, altimetrie, radar, chimique atmospherique, geophysics, altimetry, radar, atmospheric chemistry