A GIS-based fire spread simulator integrating a simplified physical wildland fire model and a wind field model

Abstract

This article discusses the integration of two models, namely, the Physical Forest Fire Spread (PhFFS) and the High Definition Wind Model (HDWM), into a GIS-based interface. The resulting tool automates data acquisition, pre-processes spatial data, launches the aforementioned models, and displays the corresponding results in a unique environment. Our implementation uses the Python language and Esri's ArcPy library to extend the functionality of ArcMap 10.4. The PhFFS is a simplified 2D physical wildland fire spread model based on conservation equations, with convection and radiation as heat transfer mechanisms. It also includes some 3D effects. The HDWM arises from an asymptotic approximation of the Navier-Stokes equations, and provides a 3D wind velocity field in an air layer above the terrain surface. Both models can be run in standalone or coupled mode. Finally, the simulation of a real fire in Galicia (Spain) confirms that the tool developed is efficient and fully operational.

Exploring a Convection–Diffusion–Reaction Model of the Propagation of Forest Fires: Computation of Risk Maps for Heterogeneous Environments

“…We may then approximate (1), (5)- (8) in semi-discrete form (that is, in discrete in space but continuous in time form) by the system of ordinary differential equations (ODEs)…”

“…As for the coefficient functions in (1), the wind velocity w(x, t) is specified by (4) (specific choices of the topography function T (x) will be introduced in Section 4.3), the diffusion function K(u) by (5) (alternative formulas will be discussed in Section 4.2), and the reaction term f (u, v, x) by (6) and (7). The fuel consumption function g(u, v) is given by (8). Values of the constants involved in K(u), f (u, v, x) and g(u, v) are provided in Section 4.1.…”

“…Further references to this model and its variants include [5][6][7]. Applications of this model to real-world wildfire scenarios in several specific geographic regions are documented in [4,8,9]. It is also the basis of the spectral algorithm advanced by San Martin and Torres [10,11], but the particular nature of that numerical method is applicable to a constant diffusion coefficient only.…”

“…Thus, although the combustion process is fully turbulent and three-dimensional, most models used for the simulation of wildfire propagation are formulated and eventually solved in two horizontal space dimensions, although some three-dimensional effects, for instance due to variation of topography, are considered. These include, in particular, [1,2,[4][5][6][7][8][9][10][11][12][13]. This simplifaction, especially for large terrains, also reflects limitations in computational resources available.…”

Discretization of the Region of Interest

“…The generated tetrahedral mesh is appropriated for finite element simulations of environmental processes, such as weather forecasting, wind field (see Chapter ?? ), fire propagation or atmospheric pollution [20,21].…”