An Efficient Method to Simulate Wildfire Propagation Using Irregular Grids

Abstract. Climate change and land-use changes are projected to make wildfires more frequent and intense, with a global increase of extreme fires of up to 14 % by 2030, 30 % by the end of 2050 and 50 % by the end of the century (Sullivan et al., 2022). This latest information has increased interest of how the large scale, often catastrophic, events can be reduced and more effectively managed. One critical area revolves around real-time fire line prediction and how resources can be better deployed to reduce the propagation of wildfires. This paper explores mathematical models for fire propagation on a fully configurable grid using the Irregular Grid Software (IGS) developed. The configurable grid allows cross comparison of both regular grids such as square, hexagonal, triangular, and irregular grids such as a randomly seeded Voronoi diagram and a flammable resolution grid (FRG). The FRG is adapted to focus attention on areas of higher importance which provides greater precision at the cost of extra computing time. The irregular grid approach and ForeFire, an existing industry standard program were compared. The comparison included simulations of wildfires located in the Wicklow Mountains, in Ireland, a region used by the fire services for exercises. The performance of the gridbased techniques was examined using a set of experiments to characterise the model’s response to key factors such as wind, elevation, and fuel type. The results show that the IGS runs on average 34 times quicker than ForeFire while retaining an average result similarity of 80 % with ForeFire. In this paper sections 1 and 2 will give an overview on existing research on wildfires and wildfire modelling. Section 3 will describe the resources that were necessary to model wildfire propagation. Section 4 explains how these resources were used to build the IGS. Section 5 compares different gird types produced using the IGS, while section 6 compares the IGS to ForeFire. Sections 7 and 8 discus these results. </jats:p>