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| Titel |
Technical Note: Sensitivity of 1-D smoke plume rise models to the inclusion of environmental wind drag |
| VerfasserIn |
S. R. Freitas, K. M. Longo, J. Trentmann, D. Latham |
| 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 ; 10, no. 2 ; Nr. 10, no. 2 (2010-01-21), S.585-594 |
| Datensatznummer |
250007963
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| Publikation (Nr.) |
 copernicus.org/acp-10-585-2010.pdf |
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| Zusammenfassung |
| Vegetation fires emit hot gases and particles which are rapidly transported
upward by the positive buoyancy generated by the combustion process. In
general, the final vertical height that the smoke plumes reach is controlled
by the thermodynamic stability of the atmospheric environment and the surface
heat flux released by the fire. However, the presence of a strong horizontal
wind can enhance the lateral entrainment and induce additional drag,
particularly for small fires, impacting the smoke injection height. In this
paper, we revisit the parameterization of the vertical transport of hot gases
and particles emitted from vegetation fires, described in Freitas et al. (2007), to
include the effects of environmental wind on transport and dilution of the
smoke plume at its scale. This process is quantitatively represented by
introducing an additional entrainment term to account for organized inflow of
a mass of cooler and drier ambient air into the plume and its drag by
momentum transfer. An extended set of equations including the horizontal
motion of the plume and the additional increase of the plume radius is solved
to simulate the time evolution of the plume rise and the smoke injection
height. One-dimensional (1-D) model results are presented for two
deforestation fires in the Amazon basin with sizes of 10 and 50 ha under
calm and windy atmospheric environments. The results are compared to
corresponding simulations generated by the complex non-hydrostatic
three-dimensional (3-D) Active Tracer High resolution Atmospheric Model
(ATHAM). We show that the 1-D model results compare well with the full 3-D
simulations. The 1-D model may thus be used in field situations where
extensive computing facilities are not available, especially under conditions
for which several optional cases must be studied. |
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