5th Symposium on Fire and Forest Meteorology and the 2nd International Wildland Fire Ecology and Fire Management Congress

Monday, 17 November 2003: 11:30 AM
Numerical Study of Effects of Atmosphere Temperature Profile on Wildfire Behavior
Chunmei Xia, Florida State University, Tallahassee, FL; and M. Y. Hussaini, P. Cunningham, R. R. Linn, and S. L. Goodrick
Poster PDF (265.6 kB)
A coupled atmosphere-fire model is employed to simulate fire behavior in wildland fuels characteristic of the Southeast United States. Specifically, we use the HIGRAD/FIRETEC model, developed at the Los Alamos National Laboratory, which solves the fully compressible transport equations for mass, momentum, species, and energy, coupled with simplified representations of combustion and radiation.

In this paper, we explore fire behavior in fuels resembling those commonly found in Florida and the Southeast United States, namely: (i) tall grass (i.e., fuels resembling those of fire behavior model 3); (ii) southern rough (i.e., fuels resembling those of fire behavior model 7); and (iii) chaparral (i.e., fuels resembling those of fire behavior model 4). The domain of computation is a rectangular box with 360m in the windward direction, 240m in the horizontal direction normal to the wind, and 615m in the vertical direction. The computational grid has a resolution of 2 m in the horizontal directions, and it is stretched in the vertical direction with appropriate clustering near the ground. The fuel distribution is assumed to be spatially homogeneous. Typical fuel loads, surface area to volume ratios, heat contents, and fuel bed depths corresponding to each fuel type will be considered. Rate of fire spread, shape of the fire front, and temperature distribution in the domain will be shown for these three fuel types for different atmospheric wind and temperature profiles and fuel moisture conditions. The purpose of this study is to examine the dependence of fire behavior on the different properties of the fuels common to the Southeast United States and on various atmospheric conditions, including typical daytime and nighttime profiles.

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