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| Titel |
Predicting the mineral composition of dust aerosols – Part 2: Model evaluation and identification of key processes with observations |
| VerfasserIn |
J. P. Perlwitz, C. Pérez García-Pando, R. L. Miller |
| 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 ; 15, no. 20 ; Nr. 15, no. 20 (2015-10-21), S.11629-11652 |
| Datensatznummer |
250120108
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| Publikation (Nr.) |
 copernicus.org/acp-15-11629-2015.pdf |
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| Zusammenfassung |
| A global compilation of nearly sixty measurement studies is used to
evaluate two methods of simulating the mineral composition of dust
aerosols in an Earth system model. Both methods are based upon
a Mean Mineralogical Table (MMT) that relates the soil mineral
fractions to a global atlas of arid soil type. The Soil Mineral
Fraction (SMF) method assumes that the aerosol mineral fractions
match the fractions of the soil. The MMT is based upon soil
measurements after wet sieving, a process that destroys aggregates
of soil particles that would have been emitted from the original,
undisturbed soil. The second method approximately reconstructs the
emitted aggregates. This model is referred to as the Aerosol Mineral
Fraction (AMF) method because the mineral fractions of the aerosols
differ from those of the wet-sieved parent soil, partly due to
reaggregation. The AMF method remedies some of the deficiencies of
the SMF method in comparison to observations. Only the AMF method
exhibits phyllosilicate mass at silt sizes, where they are abundant
according to observations. In addition, the AMF quartz fraction of
silt particles is in better agreement with measured values, in
contrast to the overestimated SMF fraction. Measurements at
distinct clay and silt particle sizes are shown to be more useful
for evaluation of the models, in contrast to the sum over all
particles sizes that is susceptible to compensating errors, as
illustrated by the SMF experiment. Model errors suggest that
allocation of the emitted silt fraction of each mineral into the
corresponding transported size categories is an important remaining
source of uncertainty. Evaluation of both models and the MMT is
hindered by the limited number of size-resolved measurements of
mineral content that sparsely sample aerosols from the major dust
sources. The importance of climate processes dependent upon aerosol
mineral composition shows the need for global and routine mineral
measurements. |
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