Evaluation of WRF-Sfire Performance with Field Observations from the FireFlux experiment

TL;DR

This paper evaluates the WRF-Sfire coupled atmosphere-fire model using FireFlux field data, demonstrating its ability to realistically simulate fire spread, plume structure, and wind changes, while identifying areas for model improvement.

Contribution

It provides a comprehensive validation of WRF-Sfire with real-world measurements and offers insights for enhancing coupled atmosphere-fire modeling accuracy.

Findings

WRF-Sfire accurately simulates fire spread and plume structure.

The model captures wind and temperature changes during fire passage.

Vertical velocities are overestimated, and horizontal winds are underestimated above 10 m.

Abstract

This study uses in-situ measurements collected during the FireFlux field experiment to evaluate and improve the performance of coupled atmosphere-fire model WRF-Sfire. The simulation by WRF-Sfire of the experimental burn shows that WRF-Sfire is capable of providing realistic head fire rate-of-spread and the vertical temperature structure of the fire plume, and, up to 10 m above ground level, fire-induced surface flow and vertical velocities within the plume. The model captured the changes in wind speed and direction before, during, and after fire front passage, along with arrival times of wind speed, temperature, and updraft maximae, at the two instrumented flux towers used in FireFlux. The model overestimated vertical velocities and underestimated horizontal wind speeds measured at tower heights above the 10 m, and it is hypothesized that the limited model resolution over estimated the fire front depth, leading to too high a heat release and, subsequently, too strong an updraft. However, on the whole, WRF-Sfire fire plume behavior is consistent with the interpretation of FireFlux observations. The study suggests optimal experimental pre-planning, design, and execution of future field campaigns that are needed for further coupled atmosphere-fire model development and evaluation.