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| Titel |
Investigation of radiative effects of the optically thick dust layer over the Indian tropical region |
| VerfasserIn |
S. K. Das, J.-P. Chen, M. Venkat Ratnam, A. Jayaraman |
| 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 ; 31, no. 4 ; Nr. 31, no. 4 (2013-04-11), S.647-663 |
| Datensatznummer |
250019022
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| Publikation (Nr.) |
 copernicus.org/angeo-31-647-2013.pdf |
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| Zusammenfassung |
| Optical and physical properties of aerosols derived from multi-satellite
observations (MODIS-Aqua, OMI-Aura, MISR-Terra, CALIOP-CALIPSO) have been
used to estimate radiative effects of the dust layer over southern India. The
vertical distribution of aerosol radiative forcing and heating rates are
calculated with 100 m resolution in the lower atmosphere, using
temperature and relative humidity data from balloon-borne radiosonde
observations. The present study investigates the optically thick dust layer
of optical thickness 0.18 ± 0.06 at an altitude of 2.5 ± 0.7 km over
Gadanki, transported from the Thar Desert, producing radiative forcing and
heating rate of 11.5 ± 3.3 W m−2 and 0.6 ± 0.26 K day−1,
respectively, with a forcing efficiency of 43 W m−2 and an effective
heating rate of 4 K day−1 per unit dust optical depth. Presence of the dust
layer increases radiative forcing by 60% and heating rate by 60 times at
that altitude compared to non-dusty cloud-free days. Calculation shows that
the radiative effects of the dust layer strongly depend on the boundary layer
aerosol type and mass loading. An increase of 25% of heating by the dust layer
is found over relatively cleaner regions than urban regions in southern India
and further 15% of heating increases over the marine region. Such heating
differences in free troposphere may have significant consequences in the
atmospheric circulation and hydrological cycle over the tropical Indian region. |
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