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| Titel |
Resolving vorticity-driven lateral fire spread using the WRF-Fire coupled atmosphere-fire numerical model |
| VerfasserIn |
C. C. Simpson, J. J. Sharples, J. P. Evans |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1561-8633
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| Digitales Dokument |
URL |
| Erschienen |
In: Natural Hazards and Earth System Sciences ; 14, no. 9 ; Nr. 14, no. 9 (2014-09-05), S.2359-2371 |
| Datensatznummer |
250118655
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| Publikation (Nr.) |
 copernicus.org/nhess-14-2359-2014.pdf |
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| Zusammenfassung |
| Vorticity-driven lateral fire spread (VLS) is a form of
dynamic fire behaviour, during which a wildland fire spreads rapidly across a
steep leeward slope in a direction approximately transverse to the background
winds. VLS is often accompanied by a downwind extension of the active flaming
region and intense pyro-convection. In this study, the WRF-Fire
(WRF stands for Weather Research and Forecasting) coupled
atmosphere–fire model is used to examine the sensitivity of resolving VLS to
both the horizontal and vertical grid spacing, and the fire-to-atmosphere
coupling from within the model framework. The atmospheric horizontal and
vertical grid spacing are varied between 25 and 90 m, and the
fire-to-atmosphere coupling is either enabled or disabled. At high spatial
resolutions, the inclusion of fire-to-atmosphere coupling increases the
upslope and lateral rate of spread by factors of up to 2.7 and 9.5,
respectively. This increase in the upslope and lateral rate of spread
diminishes at coarser spatial resolutions, and VLS is not modelled for a
horizontal and vertical grid spacing of 90 m. The lateral fire spread is
driven by fire whirls formed due to an interaction between the background
winds and the vertical circulation generated at the flank of the fire front
as part of the pyro-convective updraft. The laterally advancing fire fronts
become the dominant contributors to the extreme pyro-convection. The results
presented in this study demonstrate that both high spatial resolution and
two-way atmosphere–fire coupling are required to model VLS with WRF-Fire. |
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