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| Titel |
On the relationship of polar mesospheric cloud ice water content, particle radius and mesospheric temperature and its use in multi-dimensional models |
| VerfasserIn |
A. W. Merkel, D. R. Marsh, A. Gettelman, E. J. Jensen |
| 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 ; 9, no. 22 ; Nr. 9, no. 22 (2009-11-24), S.8889-8901 |
| Datensatznummer |
250007766
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| Publikation (Nr.) |
 copernicus.org/acp-9-8889-2009.pdf |
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| Zusammenfassung |
| The distribution of ice layers in the polar summer mesosphere (called polar
mesospheric clouds or PMCs) is sensitive to background atmospheric
conditions and therefore affected by global-scale dynamics. To investigate
this coupling it is necessary to simulate the global distribution of PMCs
within a 3-dimensional (3-D) model that couples large-scale dynamics with
cloud microphysics. However, modeling PMC microphysics within 3-D global
chemistry climate models (GCCM) is a challenge due to the high computational
cost associated with particle following (Lagrangian) or sectional
microphysical calculations. By characterizing the relationship between the
PMC effective radius, ice water content (iwc), and local temperature (T) from an
ensemble of simulations from the sectional microphysical model, the
Community Aerosol and Radiation Model for Atmospheres (CARMA), we determined
that these variables can be described by a robust empirical formula. The
characterized relationship allows an estimate of an altitude distribution of
PMC effective radius in terms of local temperature and iwc. For our purposes we
use this formula to predict an effective radius as part of a bulk
parameterization of PMC microphysics in a 3-D GCCM to simulate growth,
sublimation and sedimentation of ice particles without keeping track of the
time history of each ice particle size or particle size bin. This allows
cost effective decadal scale PMC simulations in a 3-D GCCM to be performed.
This approach produces realistic PMC simulations including estimates of the
optical properties of PMCs. We validate the relationship with PMC data from
the Solar Occultation for Ice Experiment (SOFIE). |
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