Surface matters: limitations of CALIPSO V3 aerosol typing in coastal regions
In the CALIPSO data analysis, surface type (land/ocean) is used to augment the aerosol characterization. However, this surface-dependent aerosol typing prohibits a correct classification of marine aerosol over land that is advected from ocean to land. This might result in a systematic overestimation...
| Main Authors: | , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2014-07-01
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| Series: | Atmospheric Measurement Techniques |
| Online Access: | http://www.atmos-meas-tech.net/7/2061/2014/amt-7-2061-2014.pdf |
| Summary: | In the CALIPSO data analysis, surface type (land/ocean) is used to augment
the aerosol characterization. However, this surface-dependent aerosol typing
prohibits a correct classification of marine aerosol over land that is
advected from ocean to land. This might result in a systematic overestimation
of the particle extinction coefficient and of the aerosol optical thickness
(AOT) of up to a factor of 3.5 over land in coastal areas. We present a
long-term comparison of CALIPSO and ground-based lidar observations of the
aerosol conditions in the coastal environment of
southern South America
(Punta Arenas, Chile, 53° S), performed in
December 2009–April 2010. Punta Arenas is almost entirely influenced by
marine particles throughout the year, indicated by a rather low AOT of
0.02–0.04. However, we found an unexpectedly high fraction of continental
aerosol in the aerosol types inferred by means of CALIOP observations and,
correspondingly, too high values of particle extinction. Similar features of
the CALIOP data analysis are presented for four other coastal areas around
the world. Since CALIOP data serve as important input for global climate
models, the influence of this systematic error was estimated by means of
simplified radiative-transfer calculations. |
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| ISSN: | 1867-1381 1867-8548 |