A comprehensive wind-fire-smoke simulation tool based on physical models and geospatial information.

We present a comprehensive simulation toolset for the analysis and prediction of wind fields, wildfire spread, and the propagation of their resulting smoke. It is composed of three physical simulation models that work together: HDWind, PhyFire and PhyNX.

The wind field simulation model, HDWind, is a mass consistent vertical diffusion wind field model based on an asymptotic approximation of the Navier-Stokes equations, providing a 3D wind field (which satisfies the incompressibility condition in the air layer) governed by a 2D equation that id adjusted to meteorological data obtained in a small number of points by solving an optimal control problem. PhyFire is a simplified 2D one-phase fire spread simulation model based on the principles of mass and energy conservation and that considers the radiation and convection (i.e., driven by wind and terrain slope) means of propagation, featuring the most relevant 3D effects, the influence of humidity, ambient temperature, wind, and the fuel types as well as their moisture content. The atmospheric dispersion model PhyNX is an urban scale Eulerian non-reactive multilayer air pollution model, able to describe convection, turbulent diffusion, and emission, considering the 3D wind field provided by the HDWind, and the smoke emission provided by PhyFire. The three models are solved using mainly the finite element method and some numerical and computational procedures to reduce the computational cost.

The required data to feed the simulation models such as cartographic and meteorological information are obtained from online geospatial information systems (GIS) in an automated way with little user intervention, thanks to the integration of the models with the geospatial library GDAL/OGR, which enables easy interpolation with most used standard GIS formats and services. An integration of this toolset into an easy-to-use webgis platform for their exploitation for professionals in the field of wildfire prevention will be demonstrated.