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| Titel |
Small-scale mixing processes enhancing troposphere-to-stratosphere transport by pyro-cumulonimbus storms |
| VerfasserIn |
G. Luderer, J. Trentmann, K. Hungershöfer, M. Herzog, M. Fromm, M. O. Andreae |
| 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. 23 ; Nr. 7, no. 23 (2007-12-06), S.5945-5957 |
| Datensatznummer |
250005268
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| Publikation (Nr.) |
 copernicus.org/acp-7-5945-2007.pdf |
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| Zusammenfassung |
Deep convection induced by large forest fires is an efficient
mechanism for transport of aerosol particles and trace gases into the upper
troposphere and lower stratosphere (UT/LS). For many pyro-cumulonimbus clouds
(pyroCbs) as well as other cases of severe convection without
fire forcing, radiometric observations of cloud tops in the thermal infrared (IR) reveal
characteristic structures, featuring a region of relatively high brightness
temperatures (warm center) surrounded by a U-shaped
region of low brightness temperatures.
We performed a numerical simulation of a specific case study of
pyroCb using a
non-hydrostatic cloud resolving model with a two-moment cloud
microphysics parameterization and a prognostic turbulence scheme. The model is
able to reproduce the thermal IR
structure as observed from satellite radiometry. Our findings establish a
close link between the observed temperature
pattern and small-scale mixing processes atop and downwind
of the overshooting dome of the pyroCb. Such small-scale mixing processes are
strongly enhanced by the formation and breaking of a stationary gravity wave
induced by the overshoot. They are found to increase the stratospheric
penetration of the smoke by up to almost 30 K and thus are of major significance for
irreversible transport of forest fire smoke into the lower stratosphere. |
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