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| Titel |
Modelling of sea salt concentrations over Europe: key uncertainties and comparison with observations |
| VerfasserIn |
S. Tsyro, W. Aas, J. Soares, M. Sofiev, H. Berge, G. Spindler |
| 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 ; 11, no. 20 ; Nr. 11, no. 20 (2011-10-18), S.10367-10388 |
| Datensatznummer |
250010132
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| Publikation (Nr.) |
 copernicus.org/acp-11-10367-2011.pdf |
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| Zusammenfassung |
| Sea salt aerosol can significantly affect the air quality. Sea salt can
cause enhanced concentrations of particulate matter and change particle
chemical composition, in particular in coastal areas, and therefore should
be accounted for in air quality modelling. We have used an EMEP Unified
model to calculate sea salt concentrations and depositions over Europe,
focusing on studying the effects of uncertainties in sea salt production and
lifetime on calculation results. Model calculations of sea salt have been
compared with EMEP observations of sodium concentrations in air and
precipitation for a four year period, from 2004 to 2007, including size
(fine/coarse) resolved EMEP intensive measurements in 2006 and 2007. In the
presented calculations, sodium air concentrations are between 8% and 46% overestimated, whereas concentrations in precipitation are
systematically underestimated by 65–70% for years 2004–2007. A series of
model tests have been performed to investigate the reasons for this
underestimation, but further studies are needed. The model is found to
reproduce the spatial distribution of Na+ in air and precipitation over
Europe fairly well, and to capture most of sea salt episodes. The paper
presents the main findings from a series of tests in which we compare
several different sea spray source functions and also look at the effects of
meteorological input and the efficiency of removal processes on calculated
sea salt concentrations. Finally, sea salt calculations with the EMEP model
have been compared with results from the SILAM model and observations for
2007. While the models produce quite close results for Na+ at the
majority of 26 measurement sites, discrepancies in terms of bias and
temporal correlation are also found. Those differences are believed to occur
due to differences in the representation of source function and size
distribution of sea salt aerosol, different meteorology used for model runs
and the different models' resolution. This study contributes to getting a
better insight on uncertainties associated with sea salt calculations and
thus facilitates further improvement of aerosol modelling on both regional
and global scales. |
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