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| Titel |
Evaluation of SCIAMACHY Oxygen A band cloud heights using Cloudnet measurements |
| VerfasserIn |
P. Wang, P. Stammes |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1867-1381
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 7, no. 5 ; Nr. 7, no. 5 (2014-05-19), S.1331-1350 |
| Datensatznummer |
250115760
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| Publikation (Nr.) |
 copernicus.org/amt-7-1331-2014.pdf |
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| Zusammenfassung |
| Two SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY) O2 A band cloud height products are evaluated using
ground-based radar/lidar measurements between January 2003 and December 2011.
The products are the ESA (European Space Agency) Level 2 (L2) version 5.02 cloud top height and the
FRESCO (Fast Retrieval Scheme for Clouds from the Oxygen A band) version 6
cloud height. The radar/lidar profiles are obtained at the Cloudnet sites of
Cabauw and Lindenberg, and are averaged for 1 h centered at the
SCIAMACHY overpass time. In total we have 217 cases of single-layer clouds
and 204 cases of multilayer clouds. We find that the ESA L2 cloud top height
has a better agreement with the Cloudnet cloud top height than the Cloudnet
cloud middle height. The ESA L2 cloud top height is on average 0.4 km higher
than the Cloudnet cloud top height, with a standard deviation of 3.1 km. The
FRESCO cloud height is closer to the Cloudnet cloud middle height than the
Cloudnet cloud top height. The mean difference between the FRESCO cloud
height and the Cloudnet cloud middle height is −0.1 km with a standard
deviation of 1.9 km. The ESA L2 cloud top height is higher than the FRESCO
cloud height. The differences between the SCIAMACHY cloud (top) height and
the Cloudnet cloud top height are linked to cloud optical thickness. The
SCIAMACHY cloud height products are further compared to the Cloudnet cloud
top height and the Cloudnet cloud middle height in 1 km bins. For single-layer clouds, the difference between the ESA L2 cloud top height and the
Cloudnet cloud top height is less than 1 km for each cloud bin at 3–7 km.
The difference between the FRESCO cloud height and the Cloudnet cloud middle
height is less than 1 km for each cloud bin at 0–6 km. The results are
similar for multilayer clouds, but the percentage of cases having a bias
within 1 km is smaller than for single-layer clouds. We may conclude that
the FRESCO cloud height is accurate for low and middle level clouds, whereas
the ESA L2 cloud top height is more accurate for middle level clouds. Both
products are less accurate for high clouds. |
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