An integrated approach to fire emission forecasting

In this study, we describe how WRF-SFIRE is coupled with WRF-Chem to construct an integrated forecast system for wildfire and smoke prediction. The integrated forecast system has the advantage of not requiring a separate plume-rise model and assumptions about the size and heat release from the fire in order to determine fire emissions into the atmosphere. With WRF-SFIRE, wildfire spread, plume and plume-top heights are predicted directly, at every WRF time-step, providing comprehensive meteorology and fire emissions to the chemical transport model WRF-Chem. Evaluation of the system was based on comparisons between available observations to the simulations of the 2007 Santa Ana fires. The study found overall good agreement between forecasted and observed fire spread and smoke transport for the Witch-Guejito fire. Also the simulated PM2.5 (fine particulate matter) peak concentrations matched the observations. However, the NO and ozone levels were underestimated in the simulations and the peak concentrations were mistimed. Determining the terminal or plume-top height is one of the most important aspects of simulating wildfire plume transport, and the study found overall good agreement between simulated and observed plume-top heights.