Sensitivity Simulations of the 3.30 Xichang Wildfire in 2020 Based on the WRF-Fire Model

This paper describes a fire forecast system WRF-Fire which is employed to simulate a real wildfire case in Xichang on March 30 in 2020 at 100-m resolution over the fire area to provide a fine representation of the terrain and fuel heterogeneities and explicitly resolve 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 fields simulations in the near surface layer. Especially, it can better characterize local wind field characteristics and capture microscale wind speed fluctuations, and gain more significant effect from fire-atmosphere interaction. The mass and energy released by fire model and feedback to the atmospheric model exhibit more heterogeneous characteristics. The simulated fire area aligns well with the observation, with KHAT coefficient (KC) ranging from 0.56 to 0.59 and Spatial Correlation Coefficient (SC) ranging from 0.52 to 0.59. For this real case, the influence of heterogeneous land surface factors on 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.