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Titel |
Global 2-D intercomparison of sectional and modal aerosol modules |
VerfasserIn |
D. K. Weisenstein, J. E. Penner, M. Herzog, X. Liu |
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 ; 7, no. 9 ; Nr. 7, no. 9 (2007-05-08), S.2339-2355 |
Datensatznummer |
250004953
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Publikation (Nr.) |
copernicus.org/acp-7-2339-2007.pdf |
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Zusammenfassung |
We present an intercomparison of several aerosol modules, sectional
and modal, in a global 2-D model in order to differentiate their
behavior for tropospheric and stratospheric applications. We model
only binary sulfuric acid-water aerosols in this study. Three
versions of the sectional model and three versions of the modal model
are used to test the sensitivity of background aerosol mass and size
distribution to the number of bins or modes and to the prescribed
width of the largest mode. We find modest sensitivity to the number
of bins (40 vs. 150) used in the sectional model. Aerosol mass is
found to be reduced in a modal model if care is not taken in selecting
the width of the largest lognormal mode, reflecting differences in
sedimentation in the middle stratosphere. The size distributions
calculated by the sectional model can be better matched by a modal
model with four modes rather than three modes in most but not all
situations. A simulation of aerosol decay following the 1991 eruption
of Mt. Pinatubo shows that the representation of the size distribution
can have a signficant impact on model-calculated aerosol decay rates
in the stratosphere. Between 1991 and 1995, aerosol extinction and
surface area density calculated by two versions of the modal model
adequately match results from the sectional model. Calculated
effective radius for the same time period shows more intermodel
variability, with a 20-bin sectional model performing much better than
any of the modal models. |
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