The Adjustment Factors (.ADJ) File is a ASCII text file required for any 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 BEHAVE 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. Using the tuning feature found in the Custom Fuel Model Editor actually changes the fuel model so all fire behavior parameters, heat per unit area, fire intensity, etc. are changed.
Each Adjustment Factors (.ADJ) File must contain data in the space delimited ASCII format specified below. FARSITE has a Burn Period Custom Editor (see below) 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 FARSITE 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 (1-50). As always, model numbers 1-13 are restricted to the 13 standard Fire Behavior fuel models (Anderson 1982). Models 14-50 are for custom models specified in the 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.
NOTE: an adjustment factor must be specified for each custom model used.
1 .5
2 .75
3 .5
4 .5
5 .5
6 .5
7 .5
8 1.0
9 .5
10 .75
11 .5
12 .5
13 .5
The Adjustments Factors (.ADJ) File Custom Editor is accessed through the "FARSITE Project" dialog box. The button to the right of the Adjustments Factors (.ADJ) File text box brings up the custom editor for generating or editing a Adjustments Factors (.ADJ) File.
If you currently have a Adjustments (.ADJ) File loaded, this dialog box will allow you to edit the contents of that file.
The Custom Editor allows direct editing in the text box by selecting text with the cursor, using the backspace key, and typing text similar to a text editor.
You can also use the editing tools in the Custom Editor. First select the range of lines you wish to edit with the cursor. You can use the Add and Set buttons to modify the block of lines selected in the text box.
The Add button adds the value displayed in the spin box to all the values in the currently selected lines.
The Set button replaces the values in the currently selected lines with the value displayed in the spin box.
To generate a new Adjustments (.ADJ) File click the New .ADJ File button. A new file with fuel models 1-50 and adjustment factors of 1.00 is displayed in the text box. You can edit this data as shown above.
Before clicking the OK button make sure the modified file has been saved with the Save .ADJ File button. If you don't save the changes, they will still be in effect for the current simulation, but they will be lost when the simulation is terminated. However if the Project (.FPJ) File is saved with an unsaved edited Adjustments (.ADJ) File, the Adjustments (.ADJ) File will then be automatically saved also.