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| Titel |
Modeling the global emission, transport and deposition of trace elements associated with mineral dust |
| VerfasserIn |
Y. Zhang, N. Mahowald, R. A. Scanza, E. Journet, K. Desboeufs, S. Albani, J. F. Kok, G. Zhuang, Y. Chen, D. D. Cohen, A. Paytan, M. D. Patey, E. P. Achterberg, J. P. Engelbrecht, K. W. Fomba |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 12, no. 19 ; Nr. 12, no. 19 (2015-10-12), S.5771-5792 |
| Datensatznummer |
250118120
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| Publikation (Nr.) |
 copernicus.org/bg-12-5771-2015.pdf |
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| Zusammenfassung |
| Trace element deposition from desert dust has important
impacts on ocean primary productivity, the quantification of which could be
useful in determining the magnitude and sign of the biogeochemical feedback
on radiative forcing. However, the impact of elemental deposition to remote
ocean regions is not well understood and is not currently included in global
climate models. In this study, emission inventories for eight elements
primarily of soil origin, Mg, P, Ca, Mn, Fe, K, Al, and Si are determined
based on a global mineral data set and a soil data set. The resulting
elemental fractions are used to drive the desert dust model in the Community
Earth System Model (CESM) in order to simulate the elemental concentrations
of atmospheric dust. Spatial variability of mineral dust elemental fractions
is evident on a global scale, particularly for Ca. Simulations of global
variations in the Ca / Al ratio, which typically range from around 0.1 to 5.0
in soils, are consistent with observations, suggesting that this ratio is a
good signature for dust source regions. The simulated variable fractions of
chemical elements are sufficiently different; estimates of deposition should
include elemental variations, especially for Ca, Al and Fe. The model
results have been evaluated with observations of elemental aerosol
concentrations from desert regions and dust events in non-dust regions,
providing insights into uncertainties in the modeling approach. The ratios
between modeled and observed elemental fractions range from 0.7 to 1.6,
except for Mg and Mn (3.4 and 3.5, respectively). Using the soil database
improves the correspondence of the spatial heterogeneity in the modeling of
several elements (Ca, Al and Fe) compared to observations. Total and soluble
dust element fluxes to different ocean basins and ice sheet regions have
been estimated, based on the model results. The annual inputs of soluble Mg, P,
Ca, Mn, Fe and K associated with dust using the mineral data set are 0.30 Tg,
16.89 Gg, 1.32 Tg, 22.84 Gg, 0.068 Tg, and 0.15 Tg to global oceans and ice
sheets. |
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