Sensitivity Simulations of the 30 March 2020 Xichang Wildfire in Southwest China Based on the WRF-Fire Model

This paper describes a fire forecast system WRF-Fire that is employed to simulate a real wildfire case in Xichang, Sichuan Province, Southwest China on 30 March 2020 at a 100-m resolution over the fire area, in order to provide a fine representation of the terrain and fuel heterogeneities and explicitly resolve the atmospheric turbulence. Four sensitivity experiments were conducted to analyze the impacts of atmospheric model grid spacing and fire–atmosphere interaction on simulated meteorological fields and fire behavior. The results indicate that finer horizontal grid spacing in the atmospheric model improves the accuracy of wind, temperature, and moisture simulations in the near surface layer. Especially, it can better characterize local wind field characteristics, capture microscale wind speed fluctuations, and produce more significant effect from fire–atmosphere interaction. The mass and energy released by the fire model and its feedback to the atmospheric model exhibit enhanced heterogeneous characteristics. The simulated fire area aligns well with the observation, with KHAT coefficient (KC) of 0.56–0.59 and spatial correlation coefficient (SC) of 0.52–0.59. For this real case, the influence of heterogeneous land surface on the fire behavior is much greater than the atmosphere–fire interaction. The study suggests that WRF-Fire holds high potential as a real wildfire simulation tool, offering a new and feasible approach for fire prediction.