W. Lotz

Odin/OSIRIS observations of stratospheric BrO: Retrieval methodology, climatology, and inferred Bry

A 7+ year (2001–2008) data set of stratospheric BrO profiles measured by the Optical Spectrograph and Infra-Red Imager System (OSIRIS) instrument, a UV-visible spectrometer measuring limb-scattered sunlight from the Odin satellite, is presented. Zonal mean radiance spectra are computed for each day and inverted to yield effective daily zonal mean BrO profiles from 16 to 36 km. A detailed description of the retrieval methodology and error analysis is presented. Single-profile precision and effective resolution are found to be about 30% and 3–5 km, respectively, throughout much of the retrieval range. Individual profile and monthly mean comparisons with ground-based, balloon, and satellite instruments are found to agree to about 30%. A BrO climatology is presented, and its morphology and correlation with NO2 is consistent with our current understanding of bromine chemistry. Monthly mean Bry maps are derived. Two methods of calculating total Bry in the stratosphere are used and suggest (21.0 ± 5.0) pptv with a contribution from very short lived substances of (5.0 ± 5.0) pptv, consistent with other recent estimates.

Global cloud top height and thermodynamic phase distributions as obtained by SCIAMACHY on ENVISAT

Global cloud top height spatial distribution as obtained using highly spectrally resolved (≈0.42 nm) SCIAMACHY on ENVISAT measurements in the oxygen A‐band is presented. Also the global cloud phase index map is given. The results were derived using semi‐analytical cloud retrieval algorithms developed by the authors specifically for SCIAMACHY cloud retrievals. The algorithm is applicable for clouds having an optical thickness larger than 5. Therefore, only thick cloud fields were selected for this study. We found that the global average cloud top height is close to 6 km and the most frequent value of the phase index is close to 0.8.