This command displays the "Fuel Moisture Options" dialog box which controls three options in the dead fuel moisture model contained in FARSITE:
Allows a Fuel Moisture Map (.FMM) File to be saved and reloaded,
controls when a Fuel Moisture Map is calculated,
sets the resolution of the calculated Fuel Moisture Map.
A Fuel Moisture Map (.FMM) File is automatically saved with a bookmark, but you can also save one separately for use in a different simulation. There are several important points to remember when reusing a Fuel Moisture Map (.FMM) File;
Reusing a Fuel Moisture Map (.FMM) File with a different Landscape (.LCP) File will cause FARSITE to calculate a new Fuel Moisture Map,
different or changes to the Fuel Moisture (.FMS), Fuel Model (.FMD), Weather (.WTR), or Wind (.WND) Files will cause FARSITE to calculate a new Fuel Moisture Map,
moving the duration start time or conditioning period forward will cause FARSITE to calculate a new Fuel Moisture Map,
moving the duration end time back will cause FARSITE to just calculate the additional time steps for the Fuel Moisture Map.
Given the above restrictions you should plan to calculate the Fuel Moisture Map for the most encompassing set of landscape and environmental parameters you plan on running simulations for.
Once a Fuel Moisture Map is calculated, usually with the first time step of a simulation, it can be saved as a .FMM file. After opening the "Fuel Moisture Options" dialog box, click the Insert Simulation Data for FMM Description button. This writes the following information into the FMM Description text box;
Duration settings,
Landscape (.LCP) File name,
Weather (.WTR) File name.
You can also enter any other information to help describe the Fuel Moisture Map. This FMM Description is saved in the .FMM File and displays when a Fuel Moisture Map (.FMM) File is loaded with the Load File (.FMM) button to help identify the Fuel Moisture Map.
Click the Save File (.FMM) button to open the "Select Fuel Moisture Map" dialog box, navigate to the desired directory and enter a file name. The .FMM extension is automatically added. The file is saved when you click the Save button.
Remember; Fuel Moisture Maps are also saved when a bookmark is created or updated in a Bookmark Fuel Moisture (.BFM) File. This file is identical to the Fuel Moisture Map (.FMM) File except for the different 3-letter extension which identifies it as part of a bookmark.
To load a previously saved Fuel Moisture Map (.FMM) File first make sure a project is open, then open the "Fuel Moisture Options" dialog box with the Model > Dead Fuel Moisture command. Click the Load File (.FMM) button, navigate to the previously saved Fuel Moisture Map (.FMM) File, and click the Open button in the "Select Fuel Moisture Map" dialog box. Finally click the OK button to close the "Fuel Moisture Options" dialog box.
There are two options of when in a simulation to calculate the Fuel Moisture Map;
Pre-Calculate Fuel Moisture Map,
Calculate Moisture Map As Needed.
Pre-Calculate Fuel Moisture Map is the default option and is used for most simulations. Use this option for when you have a relatively short simulation and a definite duration ending time. Pre-Calculating involves a long computational period before the first time step, but the calculation of the simulation is relatively fast.
The Calculate Moisture Map As Needed option can be useful when testing or calibrating long simulations by evaluating the first time steps and you are unsure how long you will let the simulation run. It is also useful when you want a simulation to end when it reaches a pre identified point on the landscape and don't have a good idea of how long the simulation needs to run.
In either case, the moistures do not need to be recalculated for repeated simulations unless modifications are made to the Weather (.WTR) or Initial Fuel Moisture (.FMS) Files, the duration settings (Simulate > Duration), or the options for dead fuel moisture (Model > Dead Fuel Moisture).
To limit the amount of time it takes to calculate a Fuel Moisture Map not all the combinations and permutations of variables found on a landscape are used. Instead specific points along the range of each of the five variables (time, slope, aspect, elevation, and canopy cover) are used in calculating a multidimensional array of fuel moistures. This catalogue of fuel moistures is then interpolated when requested by the simulation to obtain a fuel moisture for a particular fuel size class, elevation, slope, aspect, and canopy cover, and time.
The user can control the "resolutions" of each of the five variables used in calculating the multidimensional array of fuel moistures. Therefore the user can control the tradeoffs between accuracy and computational time.
You can create a raster Fuel Moisture Map for a particular fuel size-class and environmental variables with the Output > Environmental Maps command.