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| Titel |
Envisat MIPAS measurements of CFC-11: retrieval, validation, and climatology |
| VerfasserIn |
L. Hoffmann, M. Kaufmann, R. Spang, R. Müller, J. J. Remedios, D. P. Moore, C. M. Volk, T. Clarmann, M. Riese |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 8, no. 13 ; Nr. 8, no. 13 (2008-07-10), S.3671-3688 |
| Datensatznummer |
250006277
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| Publikation (Nr.) |
 copernicus.org/acp-8-3671-2008.pdf |
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| Zusammenfassung |
| 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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