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Titel |
Vertical distribution of aerosols over the east coast of India inferred from airborne LIDAR measurements |
VerfasserIn |
S. K. Satheesh, V. Vinoj, S. Suresh Babu, K. Krishna Moorthy, Vijayakumar S. Nair |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
0992-7689
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Digitales Dokument |
URL |
Erschienen |
In: Annales Geophysicae ; 27, no. 11 ; Nr. 27, no. 11 (2009-11-04), S.4157-4169 |
Datensatznummer |
250016700
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Publikation (Nr.) |
copernicus.org/angeo-27-4157-2009.pdf |
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Zusammenfassung |
The information on altitude distribution of
aerosols in the atmosphere is essential in assessing the impact of aerosol
warming on thermal structure and stability of the atmosphere. In addition,
aerosol altitude distribution is needed to address complex problems such as
the radiative interaction of aerosols in the presence of clouds. With this
objective, an extensive, multi-institutional and multi-platform field
experiment (ICARB-Integrated Campaign for Aerosols, gases and Radiation
Budget) was carried out under the Geosphere Biosphere Programme of the
Indian Space Research Organization (ISRO-GBP) over continental India and
adjoining oceans during March to May 2006. Here, we present airborne LIDAR
measurements carried out over the east Coast of the India during the ICARB
field campaign. An increase in aerosol extinction (scattering + absorption)
was observed from the surface upwards with a maximum around 2 to 4 km.
Aerosol extinction at higher atmospheric layers (>2 km) was two to three
times larger compared to that of the surface. A large fraction (75–85%)
of aerosol column optical depth was contributed by aerosols located above 1 km.
The aerosol layer heights (defined in this paper as the height at which
the gradient in extinction coefficient changes sign) showed a gradual
decrease with an increase in the offshore distance. A large fraction
(60–75%) of aerosol was found located above clouds indicating enhanced
aerosol absorption above clouds. Our study implies that a detailed
statistical evaluation of the temporal frequency and spatial extent of
elevated aerosol layers is necessary to assess their significance to the
climate. This is feasible using data from space-borne lidars such as
CALIPSO, which fly in formation with other satellites like MODIS AQUA and
MISR, as part of the A-Train constellation. |
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