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| Titel |
GOMOS ozone profile validation using ground-based and balloon sonde measurements |
| VerfasserIn |
J. A. E. Gijsel, D. P. J. Swart, J.-L. Baray, H. Bencherif, H. Claude, T. Fehr, S. Godin-Beekmann, G. H. Hansen, P. Keckhut, T. Leblanc, I. S. McDermid, Y. J. Meijer, H. Nakane, E. J. Quel, K. Stebel, W. Steinbrecht, K. B. Strawbridge, B. I. Tatarov, E. A. Wolfram |
| 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 ; 10, no. 21 ; Nr. 10, no. 21 (2010-11-08), S.10473-10488 |
| Datensatznummer |
250008878
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| Publikation (Nr.) |
 copernicus.org/acp-10-10473-2010.pdf |
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| Zusammenfassung |
The validation of ozone profiles retrieved by satellite instruments through
comparison with data from ground-based instruments is important to monitor
the evolution of the satellite instrument, to assist algorithm development
and to allow multi-mission trend analyses.
In this study we compare ozone profiles derived from GOMOS night-time
observations with measurements from lidar, microwave radiometer and balloon
sonde. Collocated pairs are analysed for dependence on several geophysical
and instrument observational parameters. Validation results are presented
for the operational ESA level 2 data (GOMOS version 5.00) obtained during
nearly seven years of observations and a comparison using a smaller dataset
from the previous processor (version 4.02) is also included.
The profiles obtained from dark limb measurements (solar zenith angle
>107°) when the provided processing flag is properly considered match
the ground-based measurements within ±2 percent over the altitude range
20 to 40 km. Outside this range, the pairs start to deviate more and there
is a latitudinal dependence: in the polar region where there is a higher
amount of straylight contamination, differences start to occur lower in the
mesosphere than in the tropics, whereas for the lower part of the
stratosphere the opposite happens: the profiles in the tropics reach less
far down as the signal reduces faster because of the higher altitude at
which the maximum ozone concentration is found compared to the mid and polar
latitudes. Also the bias is shifting from mostly negative in the polar
region to more positive in the tropics
Profiles measured under "twilight" conditions are often matching the
ground-based measurements very well, but care has to be taken in all cases
when dealing with "straylight" contaminated profiles.
For the selection criteria applied here (data within 800 km, 3 degrees in
equivalent latitude, 20 h (5 h above 50 km) and a relative ozone
error in the GOMOS data of 20% or less), no dependence was found on
stellar magnitude, star temperature, nor the azimuth angle of the line of
sight. No evidence of a temporal trend was seen either in the bias or
frequency of outliers, but a comparison applying less strict data selection
criteria might show differently. |
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