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| Titel |
Modeling the distribution of ammonia across Europe including bi-directional surface–atmosphere exchange |
| VerfasserIn |
R. J. Wichink Kruit, M. Schaap, F. J. Sauter, M. C. Zanten, W. A. J. Pul |
| 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 ; 9, no. 12 ; Nr. 9, no. 12 (2012-12-18), S.5261-5277 |
| Datensatznummer |
250007469
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| Publikation (Nr.) |
 copernicus.org/bg-9-5261-2012.pdf |
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| Zusammenfassung |
| A large shortcoming of current chemistry transport models (CTM) for
simulating the fate of ammonia in the atmosphere is the lack of a
description of the bi-directional surface–atmosphere exchange. In this
paper, results of an update of the surface–atmosphere exchange module DEPAC,
i.e. DEPosition of Acidifying Compounds, in the chemistry transport model
LOTOS-EUROS are discussed. It is shown that with the new description, which
includes bi-directional surface–atmosphere exchange, the modeled ammonia
concentrations increase almost everywhere, in particular in agricultural
source areas. The reason is that by using a compensation point the ammonia
lifetime and transport distance is increased. As a consequence, deposition
of ammonia and ammonium decreases in agricultural source areas, while it
increases in large nature areas and remote regions especially in southern
Scandinavia. The inclusion of a compensation point for water reduces the dry
deposition over sea and allows reproducing the observed marine background
concentrations at coastal locations to a better extent. A comparison with
measurements shows that the model results better represent the measured
ammonia concentrations. The concentrations in nature areas are slightly
overestimated, while the concentrations in agricultural source areas are
still underestimated. Although the introduction of the compensation point
improves the model performance, the modeling of ammonia remains challenging.
Important aspects are emission patterns in space and time as well as a
proper approach to deal with the high concentration gradients in relation to
model resolution. In short, the inclusion of a bi-directional surface–atmosphere
exchange is a significant step forward for modeling ammonia. |
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