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| Titel |
Evaluation of a regional air-quality model with bidirectional NH3 exchange coupled to an agroecosystem model |
| VerfasserIn |
J. O. Bash, E. J. Cooter, R. L. Dennis, J. T. Walker, J. E. Pleim |
| 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 ; 10, no. 3 ; Nr. 10, no. 3 (2013-03-11), S.1635-1645 |
| Datensatznummer |
250018145
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| Publikation (Nr.) |
 copernicus.org/bg-10-1635-2013.pdf |
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| Zusammenfassung |
| Atmospheric ammonia (NH3) is the primary atmospheric base and an
important precursor for inorganic particulate matter and when deposited
NH3 contributes to surface water eutrophication, soil acidification and
decline in species biodiversity. Flux measurements indicate that the
air–surface exchange of NH3 is bidirectional. However, the effects of
bidirectional exchange, soil biogeochemistry and human activity are not
parameterized in air quality models. The US Environmental Protection
Agency's (EPA) Community Multiscale Air-Quality (CMAQ) model with
bidirectional NH3 exchange has been coupled with the United States
Department of Agriculture's (USDA) Environmental Policy Integrated Climate
(EPIC) agroecosystem model. The coupled CMAQ-EPIC model relies on EPIC
fertilization timing, rate and composition while CMAQ models the soil
ammonium (NH4+) pool by conserving the ammonium mass due to
fertilization, evasion, deposition, and nitrification processes. This
mechanistically coupled modeling system reduced the biases and error in
NHx (NH3 + NH4+) wet deposition and in ambient aerosol
concentrations in an annual 2002 Continental US (CONUS) domain simulation
when compared to a 2002 annual simulation of CMAQ without bidirectional
exchange. Fertilizer emissions estimated in CMAQ 5.0 with bidirectional
exchange exhibits markedly different seasonal dynamics than the US EPA's
National Emissions Inventory (NEI), with lower emissions in the spring and
fall and higher emissions in July. |
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