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Titel |
WRF-Chem simulations of a typical pre-monsoon dust storm in northern India: influences on aerosol optical properties and radiation budget |
VerfasserIn |
R. Kumar, M. C. Barth, G. G. Pfister, M. Naja, G. P. Brasseur |
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 ; 14, no. 5 ; Nr. 14, no. 5 (2014-03-10), S.2431-2446 |
Datensatznummer |
250118469
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Publikation (Nr.) |
copernicus.org/acp-14-2431-2014.pdf |
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Zusammenfassung |
The impact of a typical pre-monsoon season (April–June) dust storm event on
the regional aerosol optical properties and radiation budget in northern
India is analyzed. The dust storm event lasted from 17 to 22 April 2010 and
the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem)
estimated total dust emissions of 7.5 Tg over the model domain. Both in situ
(AERONET – Aerosol Robotic Network) and satellite observations show
significant increase (> 50%) in local to regional scale
aerosol optical depth (AOD) and decrease (> 70%) in the
Ångström exponent (α) during this period. Amongst the AERONET
sites in this region, Kanpur was influenced the most, where the AOD reached
up to 2.1 and the α decreased to −0.09 during the dust storm
period. The WRF-Chem model reproduced the spatial and temporal distributions
of dust plumes and aerosol optical properties but generally underestimated
the AOD. The average MODIS and WRF-Chem AOD (550 nm) values in a subregion
(70–80° E, 25–30° N) affected the most by the dust storm
are estimated as 0.80 ± 0.30 and 0.68 ± 0.28, respectively. Model
results show that dust particles cool the surface and the top of the
atmosphere, but warm the atmosphere itself. The radiative perturbation due to
dust aerosols averaged over the subregion is estimated as
−2.9 ± 3.1 W m−2 at the top of the atmosphere,
5.1 ± 3.3 W m−2 in the atmosphere and
−8.0 ± 3.3 W m−2 at the surface. The simulated instantaneous
cooling under the dust plume was much higher and reached −227 and
−70 W m−2 at the surface and the top of the atmosphere,
respectively. The impact of these radiative perturbations on the surface
energy budget is estimated to be small on a regional scale but significant
locally. |
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