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| Titel |
Radiation closure and diurnal cycle of the clear-sky dust instantaneous direct radiative forcing over Arabian Peninsula |
| VerfasserIn |
Sergey Osipov, Georgiy Stenchikov, Helen Brindley, Jamie Banks |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250104717
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| Publikation (Nr.) |
 EGU/EGU2015-4149.pdf |
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| Zusammenfassung |
| To better quantify radiative effects of dust over the Arabian Peninsula we have
developed a standalone column radiation transport model coupled with the Mie
calculations and driven by reanalysis meteorological fields and atmospheric composition.
Numerical experiments are carried out for a wide range of aerosol optical depths,
including extreme values developed during the dust storm on 18-20 March 2012.
Comprehensive ground-based observations and satellite retrievals are used to estimate
aerosol optical properties, validate calculations and carry out radiation closure. The
broadband surface albedo, fluxes at the bottom and top of the atmosphere as well as
instantaneous dust radiative forcing are estimated both from the model and from
observations. Diurnal cycle of the the shortwave instantaneous dust direct radiative
forcing is studied for a range of aerosol and surface characteristics representative
for the Arabian Peninsula. Mechanisms and parameters responsible for diurnal
variability of the radiative forcing are evaluated. We found that intrinsic variability
of the surface albedo and its dependence on atmospheric conditions along with
anisotropic aerosol scattering are mostly responsible for diurnal effects. We also
discuss estimates of the climatological dust instantaneous direct radiative forcing over
land and the Red Sea using two approaches. The first approach is based on the
probability density function of the aerosol optical depth, and the second is based on the
climatologically average Spinning Enhanced Visible and Infrared Imager (SEVIRI) aerosol
optical depth. Results are compared with Geostationary Earth Radiation Budget
(GERB) derived top of the atmosphere climatological forcing over the Red Sea. |
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