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| Titel |
Modeling sea-salt aerosol in a coupled climate and sectional microphysical model: mass, optical depth and number concentration |
| VerfasserIn |
T. Fan, O. B. Toon |
| 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. 9 ; Nr. 11, no. 9 (2011-05-16), S.4587-4610 |
| Datensatznummer |
250009722
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| Publikation (Nr.) |
 copernicus.org/acp-11-4587-2011.pdf |
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| Zusammenfassung |
| Sea-salt aerosol mass, optical depth, and number concentration over the global oceans have significant
implications for aerosol direct and indirect climate effects. We model
sea-salt aerosol in a coupled climate and sectional microphysical model,
CAM/CARMA, with aerosol dynamics including sea-salt emission, gravitational
sedimentation, dry deposition, wet scavenging, and hygroscopic growth. We aim
to find an integrated sea-salt source function parameterization in the global
climate model to simultaneously represent mass, optical depth, and number
concentration. Each of these quantities is sensitive to a different part of
the aerosol size distribution, which requires a size resolved microphysical
model to treat properly. The CMS source function introduced in this research,
based upon several earlier source functions, reproduces measurements of mass,
optical depth and number concentration as well as the size distribution
better than other source function choices we tried. However, as we note, it
is also important to properly set the removal rate of the particles. The
source function and removal rate are coupled in producing observed
abundances. We find that sea salt mass and optical depth peak in the winter,
when winds are highest. However, surprisingly, particle numbers and CCN
concentrations peak in summer when rainfall is lowest. The quadratic
dependence of sea-salt optical depth on wind speed, observed by some, is well
represented in the model. We also find good agreement with the wind speed
dependency of the number concentration at the measurement location and the
regional scale. The work is the basis for further investigation of the
effects of sea-salt aerosol on climate and atmospheric chemistry. |
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