The ROS Adjustment (.ADJ) File is a optional ASCII text file for a FARSITE simulation.
Rate of spread adjustment factors allow the user to use experienced judgment or local data to tune the simulation to observed or actual fire spread patterns (see spread patterns Limitations and Assumptions). These factors have the same purpose as adjustments for BehavePlus predictions (Rothermel and Rinehart 1983). Factors are fuel model specific and are multiplied by the rate of spread to achieve the specified adjustment. For example, spread rate for a given fuel type would be reduced by half with an adjustment factor of 0.5, and a quarter with a factor of 0.25. Similarly, spread rate would be doubled using a factor of 2.0. Keeping the adjustment factors at 1.0 maintains the original spread rate.
As described in Limitations and Assumptions, simulating fire spread over long spaces and times may tend to over predict fire spread because of the coarse spatial and temporal scale of data used for the calculations. This coarse scale does not reflect the finer-scale heterogeneities that;
prevent fire from reaching an equilibrium spread rate, or
change fire shape (e.g fluctuating wind direction).
Spread rate may also be under predicted because of errors in fuel typing, inaccurate fuel moistures, or improperly represented local winds, etc.
Adjustment factors only modify the Rates of Spread for a simulation. To affect other fire behavior characteristics such as flame length, heat per unit area, fire intensity, etc. you will need to change fuel models or even develop Custom Fuel Models.
Each Adjustment Factors (.ADJ) File must contain data in the space delimited ASCII format specified below. Clicking the to help you create or edit Adjustment Factors (.ADJ) Files. Or, a generic text editing application such as Notepad or WordPad, a spreadsheet, or the FlamMap Text Editor can be used to create or edit ASCII text files. The following ASCII space delimited format is used for the Adjustment Factors (.ADJ) File.
FuelMod AdjustmentFactor
FuelMod is an integer value (1-255). As always, model numbers 1-13 are restricted to the 13 standard Fire Behavior fuel models (Anderson 1982) and some numbers between 90-219 are reserved for the expanded set of standard fuel models (Scott and Burgan, in prep.). Models 14-89 are for optional custom fuel models specified in the Custom Fuel Model (.FMD) File.
The AdjustmentFactor can be a floating point number (decimal) specifying the multiplier for rate of spread adjustment (see above). It must be greater than zero.