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Luderer et al 2007, Small-scale mixing processes enhancing.pdf | 3,98 MB | Adobe PDF | View/Open |
Title: | Small-scale mixing processes enhancing troposphere-to-stratosphere transport by pyro-cumulonimbus storms |
Authors: | Luderer, G.; Trentmann, J.; Hungershöfer, K.; Herzog, M.; Fromm, M.; Andreae, M.O. |
Publishers Version: | https://doi.org/10.5194/acp-7-5945-2007 |
Issue Date: | 2007 |
Published in: | Atmospheric Chemistry and Physics Vol. 7 (2007), No. 23 |
Publisher: | Göttingen : Copernicus GmbH |
Abstract: | 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. |
Keywords: | aerosol; atmospheric convection; forest fire; parameterization; stratosphere-troposphere interaction |
DDC: | 550 |
License: | CC BY-NC-SA 2.5 Unported |
Link to License: | https://creativecommons.org/licenses/by-nc-sa/2.5/ |
Appears in Collections: | Umweltwissenschaften |
This item is licensed under a Creative Commons License