Gustiness and its influence on wildfire

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Since 1999 I have, with the support of the US Forest Service, and colleagues at the University of Utah and the National Institute for Standards and Technology, developed two different numerical tools for studying wildfire behavior. The first is a coupling of simple operational wildfire behavior and wildfire spread rate models with a 3-dimensional, non-hydrostatic, cloud-resolving numerical prediction model, that resolves the interactions between convection from the fire and the surrounding atmosphere, fuel, and topography. The second is a coupling of a hydrodynamical numerically efficient model to predict local air flow and smoke production with an atmospheric transport/wildfire behavior model based on the principals of conservation of mass, momentum, and energy, that treats fire combusion in a more physical fashion, and not based on the empirical and prescribed formulations that characterize current operational wildfire models. We plan to use both these tools to to establish what processes determine surface wind gusts and how surface wind gustiness influences wildland fire behavior.  Determination of wind gusts is important to fire weather forecasting, especially for severe wildland fire events, and gustiness has implications for many aspects of wildland fire management. Wind gustiness, for instance, influences the performing and design of perscribed burns.  When gusts exceed a given threshold, very dangerous and uncontrollable fire behavior can be expected due to wind-induced severe and erratic fire behavior.  An accurate estimate is invaluable to prevent or limit the danger due to sudden severe fire behavior, and an aid to help organize the safety of wildland fire fighters. We emphasize that by using these numerical tools we can study for the first time the evolution of many different aspects of wildfire behavior, combustion, and smoke, at multiple scales, and under controlled conditions.