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| Titel |
Evaluation of dust and trace metal estimates from the Community Multiscale Air Quality (CMAQ) model version 5.0 |
| VerfasserIn |
K. W. Appel, G. A. Pouliot, H. Simon, G. Sarwar, H. O. T. Pye, S. L. Napelenok, F. Akhtar, S. J. Roselle |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1991-959X
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| Digitales Dokument |
URL |
| Erschienen |
In: Geoscientific Model Development ; 6, no. 4 ; Nr. 6, no. 4 (2013-07-04), S.883-899 |
| Datensatznummer |
250017854
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| Publikation (Nr.) |
 copernicus.org/gmd-6-883-2013.pdf |
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| Zusammenfassung |
| The Community Multiscale Air Quality (CMAQ) model is a state-of-the-science
air quality model that simulates the emission, transformation, transport, and
fate of the many different air pollutant species that comprise particulate
matter (PM), including dust (or soil). The CMAQ model version 5.0 (CMAQv5.0)
has several enhancements over the previous version of the model for
estimating the emission and transport of dust, including the ability to
track the specific elemental constituents of dust and have the model-derived
concentrations of those elements participate in chemistry. The latest
version of the model also includes a parameterization to estimate emissions
of dust due to wind action. The CMAQv5.0 modeling system was used to
simulate the entire year 2006 for the continental United States, and the
model estimates were evaluated against daily surface-based measurements from
several air quality networks. The CMAQ modeling system overall did well
replicating the observed soil concentrations in the western United States
(mean bias generally around ±0.5 μg m−3); however, the
model consistently overestimated the observed soil concentrations in the
eastern United States (mean bias generally between 0.5–1.5 μg m−3), regardless of season. The performance of the individual trace
metals was highly dependent on the network, species, and season, with
relatively small biases for Fe, Al, Si, and Ti throughout the year at the Interagency
Monitoring of Protected Visual Environments (IMPROVE) sites, while Ca, K, and Mn were overestimated and Mg underestimated.
For the urban Chemical Speciation Network (CSN) sites, Fe, Mg, and Mn, while overestimated, had
comparatively better performance throughout the year than the other trace
metals, which were consistently overestimated, including very large
overestimations of Al (380%), Ti (370%) and Si (470%) in the fall.
An underestimation of nighttime mixing in the urban areas appears to
contribute to the overestimation of trace metals. Removing the anthropogenic
fugitive dust (AFD) emissions and the effects of wind-blown dust (WBD)
lowered the model soil concentrations. However, even with both AFD emissions
and WBD effects removed, soil concentrations were still often overestimated,
suggesting that there are other sources of errors in the modeling system
that contribute to the overestimation of soil components. Efforts are
underway to improve both the nighttime mixing in urban areas and the spatial
and temporal distribution of dust-related emission sources in the emissions
inventory. |
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