How to diagnose fuel properties in WRF-SFIRE

The fuel properties in WRF-Fire are given in file namelist.fire. These serve to create coefficients in the Rothermel's formula. To aid diagnostics it is useful to graph the resulting fire spread rate as a function of wind and slope. The graphs are available in metric units, as well as in English units for direct comparison with the published spread rate graphs for the Scott-Burgan fuel categories.

Prerequisites

• Compile and run WRF-Fire
• Matlab

Step-by-step instructions

• Run WRF-Fire, you can kill it right after the the first time step. There will be file fuels.m in the current directory.
• Start Matlab in the directory test/em_fire to set up the search path properly.
• In Matlab, navigate to the directory with the fuels.m file
• Type fuels. This will create variable fuel. Say you want to check fuel 3. Type fuel(3) to see what is there.
• Type plot_fuel(fuel(3)) to create the graph below in metric units, and plot_fuel(fuel(3),'sb') for the same units as in Scott and Burgan (2005). The graph data are created in WRF-Fire and stored in the fuel variable.
• Type edit fire_ros to see the fire spread rate calculation in Matlab.
• Type big(check_ros(fuel)) to make sure the calculation is the same as in WRF-Fire, it should return rounding error only (less than 1e-4)

Works with

• WRF-Fire 12 Sep 2010 and hopefully later
• Matlab R2010a

References

• Rothermel, R.C. 1972. A mathematical model for predicting fire spread in wildland fuels. Res. Pap. INT-115. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Forest and Range Experiment Station. 40 pp. pdf
• Scott, J. H. and Burgan, R. E., 2005. Standard fire behavior fuel models: a comprehensive set for use with Rothermel's surface fire spread model. Gen. Tech. Rep. RMRS-GTR-153. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, 72 pp. pdf