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| Titel |
Multi-variate probability density functions with dynamics for cloud droplet activation in large-scale models: single column tests |
| VerfasserIn |
H. Guo, J.-C. Golaz, L. J. Donner, V. E. Larson, D. P. Schanen, B. M. Griffin |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1991-959X
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| Digitales Dokument |
URL |
| Erschienen |
In: Geoscientific Model Development ; 3, no. 2 ; Nr. 3, no. 2 (2010-10-08), S.475-486 |
| Datensatznummer |
250000951
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| Publikation (Nr.) |
 copernicus.org/gmd-3-475-2010.pdf |
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| Zusammenfassung |
Successful simulation of cloud-aerosol interactions (indirect aerosol effects) in climate models
requires relating grid-scale aerosol, dynamic, and thermodynamic fields to small-scale processes like
aerosol activation. A turbulence and cloud parameterization, based on multi-variate
probability density functions of sub-grid vertical velocity, temperature,
and moisture, has been
extended to treat aerosol activation. Multi-variate probability density functions
with dynamics (MVD PDFs) offer
a solution to the problem of
the gap between the resolution of climate models and the scales relevant for aerosol activation
and a means to overcome the limitations of diagnostic estimates of cloud droplet number concentration
based only on aerosol concentration.
Incorporated into the single-column version of GFDL AM3, the MVD
PDFs successfully simulate cloud properties including precipitation for
cumulus, stratocumulus, and cumulus-under-stratocumulus. The extension to
treat aerosol activation predicts droplet number concentrations in good
agreement with large eddy simulations (LES). The droplet number
concentrations
from the MVD PDFs
match LES results more closely than diagnostic relationships between aerosol concentration
and droplet concentration.
In the single-column model simulations, as
aerosol concentration increases, droplet concentration increases, precipitation decreases, but liquid water path can increase or decrease. |
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