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| Titel |
Validation of aerosol and cloud layer structures from the space-borne lidar CALIOP using a ground-based lidar in Seoul, Korea |
| VerfasserIn |
S.-W. Kim, S. Berthier, J.-C. Raut, P. Chazette, F. Dulac, S.-C. Yoon |
| 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 (2008-07-11), S.3705-3720 |
| Datensatznummer |
250006279
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| Publikation (Nr.) |
 copernicus.org/acp-8-3705-2008.pdf |
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| Zusammenfassung |
| We present initial validation results of the space-borne lidar CALIOP
onboard CALIPSO satellite using coincidental observations from a
ground-based lidar in Seoul National University (SNU), Seoul, Korea
(37.46° N, 126.95° E). We analyze six selected cases between September
2006 and February 2007, including 3 daytime and 3 night-time observations
and covering different types of clear and cloudy atmospheric conditions.
Apparent scattering ratios calculated from the two lidar measurements of
total attenuated backscatter at 532 nm show similar aerosol and cloud layer
structures both under cloud-free conditions and in cases of multiple aerosol
layers underlying semi-transparent cirrus clouds. Agreement on top and base
heights of cloud and aerosol layers is generally within 0.10 km,
particularly during night-time. This result confirms that the CALIPSO
science team algorithms for the discrimination of cloud and aerosol as well
as for the detection of layer top and base altitude provide reliable
information in such atmospheric conditions. This accuracy of the planetary
boundary layer top height under cirrus cloud appears, however, limited
during daytime. Under thick cloud conditions, however, information on the
cloud top (bottom) height only is reliable from CALIOP (ground-based lidar)
due to strong signal attenuations. However, simultaneous space-borne CALIOP
and ground-based SNU lidar (SNU-L) measurements complement each other and
can be combined to provide full information on the vertical distribution of
aerosols and clouds. An aerosol backscatter-to-extinction ratio (BER) estimated
from lidar and sunphotometer synergy at the SNU site during the CALIOP
overpass is assessed to be 0.023±0.004 sr−1 (i.e. a lidar ratio of
43.2±6.2 sr) from CALIOP and 0.027±0.006 sr−1 (37.4±7.2 sr)
from SNU-L. For aerosols within the planetary boundary layer under
cloud-free conditions, the aerosol extinction profiles from both lidars are
in agreement within about 0.02 km−1. Under semi-transparent cirrus
clouds, such profiles also show good agreement for the night-time CALIOP
flight, but large discrepancies are found for the daytime flights due to a
small signal-to-noise ratio of the CALIOP data. |
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