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Envisat MIPAS measurements of CFC-11 : Retrieval, validation, and climatology

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journal contribution
posted on 10.02.2016, 11:12 by L. Hoffmann, M. Kaufmann, R. Spang, R. Müller, John J. Remedios, D. P. Moore, C. M. Volk, T. J. Von Clarmann, M. Riese
From July 2002 to March 2004 the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) aboard the European Space Agency's Environmental Satellite (Envisat) measured nearly continuously mid infrared limb radiance spectra. These measurements are utilised to retrieve the global distribution of the chlorofluorocarbon CFC-11 by applying a new fast forward model for Envisat MIPAS and an accompanying optimal estimation retrieval processor. A detailed analysis shows that the total retrieval errors of the individual CFC-11 volume mixing ratios are typically below 10% in the altitude range 10 to 25 km and that the systematic components dominate. Contribution of a priori information to the retrieval results are less than 5 to 10% and the vertical resolution of the observations is about 3 to 4 km in the same vertical range. The data are successfully validated by comparison with several other space experiments, an air-borne in-situ instrument, measurements from ground-based networks, and independent Envisat MIPAS analyses. The retrieval results from 425 000 Envisat MIPAS limb scans are compiled to provide a new climatological data set of CFC-11. The climatology shows significantly lower CFC-11 abundances in the lower stratosphere compared with the Reference Atmospheres for MIPAS (RAMstan V3.1) climatology. Depending on the atmospheric conditions the differences between the climatologies are up to 30 to 110 ppt (45 to 150%) at 19 to 27 km altitude. Additionally, time series of CFC-11 mean abundance and variability for five latitudinal bands are presented. The observed CFC-11 distributions can be explained by the residual mean circulation and large-scale eddy-transports in the upper troposphere and lower stratosphere. The new CFC-11 data set is well suited for further scientific studies.

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Citation

Atmospheric Chemistry and Physics Discussions, 2008, 8 (2), pp. 4561-4602

Author affiliation

/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy

Version

VoR (Version of Record)

Published in

Atmospheric Chemistry and Physics Discussions

Publisher

Copernicus Publications on behalf of the European Geosciences Union

issn

1680-7367

eissn

1680-7375

Acceptance date

12/06/2008

Copyright date

2008

Available date

10/02/2016

Publisher version

http://www.atmos-chem-phys.net/8/3671/2008/

Language

en

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