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| Titel |
The Mineral Dust Cycle in EMAC 2.40: sensitivity to the spectral resolution and the dust emission scheme |
| VerfasserIn |
G. Gläser, A. Kerkweg, H. Wernli |
| 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 ; 12, no. 3 ; Nr. 12, no. 3 (2012-02-14), S.1611-1627 |
| Datensatznummer |
250010650
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| Publikation (Nr.) |
 copernicus.org/acp-12-1611-2012.pdf |
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| Zusammenfassung |
| This first detailed analysis of the mineral dust cycle in the ECHAM5/MESSy
Atmospheric Chemistry (EMAC) model system investigates the performance of two
dust emission schemes, following the approach of Balkanski
et al. (2004) and Tegen et al. (2002), respectively, and the influence of the horizontal model
resolution. Here the spectral resolutions T42, T63, T85, and T106 are
investigated. A basic sulphur chemistry, enabling the coating of insoluble
dust particles to make them soluble, is employed in order to realistically
describe the ageing and wet deposition of mineral dust. Independent of the
dust emission scheme the five-year simulations with the horizontal
resolutions T42 and T63 produce unrealistically high emissions at some grid
points in the Tarim Basin in Central Asia, leading to very high dust loads in
polar regions. With these coarse resolutions, dust source grid points in the
basin and elevated grid points of the Himalayas with high wind speeds cannot
be distinguished, causing this overestimation. In T85 and T106 these regions
are well separated and considerably less dust is emitted there. With the
chosen model setup, the dust emission scheme by Balkanski et al. (2004) places
the global maximum of emissions in the Thar Desert in India. This is
unrealistic as the Sahara Desert is known to be the largest dust source in
the world. This is the main deficiency of this scheme compared to the one by
Tegen et al. (2002), which, based on a qualitative comparison to AEROCOM data,
produces a very reasonable distribution of emissions and dust loads in
simulations with resolutions T85 and T106. For future climate simulations
with EMAC focusing on mineral dust, we recommend to use the dust emission
scheme by Tegen et al. (2002) and a model resolution of at least T85.
Simulations of two selected episodes and comparison to observational data
sets show that in this model configuration EMAC is able to realistically
simulate also intense, episodic events of dust emission and long-range
transport. |
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