Math Modeling Seminar: Computational Fluid Dynamics Model of Wildfire Behavior

Capturing the Sensitivity of Wildfire Spread to Small Perturbations in Atmospheric Conditions Using a Computational Fluid Dynamics Model of Wildfire Behavior

Dr. Alexandra Jonko
Staff Scientist
ATEAM Team Leader
Computational Earth Science Group
Los Alamos National Laboratory

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Atmospheric forcing and interactions between fire and atmosphere are primary drivers of wildland fire behavior. The atmosphere is known to be a chaotic system which, although deterministic, is very sensitive to small perturbations to initial conditions. We assume that as a result of the tight coupling between fire and atmosphere, wildland fire behavior, in turn, should also be sensitive to small perturbations in atmospheric initial conditions. Observations from experimental burns suggest that low-intensity fire in particular is susceptible to small perturbations in the wind field, which can significantly alter fire spread. Here we employ a computational fluid dynamics model of coupled fire-atmosphere interactions to answer the question: How sensitive is fire behavior to small variations in atmospheric turbulence? We perform ensemble simulations of fires in homogenous grass fuels. The only difference between ensemble members is the state of the turbulent atmosphere provided to the model throughout the simulation. We find a wide range of outcomes, with area burned ranging from 2212 m2 to 11236 m2 (400% change), driven by sensitivity to variability in both initial and boundary atmospheric conditions during the initial 30 seconds of simulation. Our results highlight the need for ensemble simulations, especially when considering fire behavior in marginal burning conditions, such as during prescribed fire application.

Speaker Bio:
Dr. Alex Jonko is an atmospheric scientist interested in modeling wildland fire behavior and fire-climate interactions. Alex is a staff member in the Computational Earth Science Group at Los Alamos National Laboratory. She has a B.S/M.S. equivalent degree in Meteorology from the University of Bonn, Germany, and a Ph.D. in Atmospheric Science from Oregon State University. In her free time, she enjoys exploring the outdoors around Los Alamos on foot, bike, and skis, fermenting vegetables and baking sourdough bread.

Intended Audience:
Undergraduates, graduates, and experts. Those with interest in the topic.
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The Math Modeling Seminar will recur each week throughout the semester on the same day and time. Find out more about upcoming speakers on the Mathematical Modeling Seminar Series webpage.

Nathan Cahill
Event Snapshot
When and Where
March 02, 2021
2:00 pm - 2:50 pm
Room/Location: See Zoom Registration Link

Open to the Public

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