Parameter Reference

This page lists commonly used configurable parameters that control ForeFire’s behavior, focusing on those documented in previous versions and still present in ForeFire V2. Parameters are case-sensitive.

How to Set Parameters

You can set parameters using the setParameter or setParameters commands in the ForeFire interpreter or a script file (.ff).

  • Single Parameter:

    setParameter[parameterName=value]
setParameter[perimeterResolution=30]
setParameter[propagationModel=Rothermel]

  • Multiple Parameters:

    setParameters[param1=value1;param2=value2;...]
setParameters[perimeterResolution=30;spatialIncrement=1.5;dumpMode=geojson]

List of Parameters

Parameters are grouped below by category for easier navigation.

File and Directory Paths

caseDirectory

  • Description: Base directory for the simulation case. Affects relative path resolution for other files.

  • Default: Current working directory (. determined by getenv(“PWD”))

ForeFireDataDirectory

  • Description: Directory containing auxiliary ForeFire data, often relative to caseDirectory.

  • Default: ForeFire

experiment

  • Description: Name identifier for the simulation experiment. May affect output filenames.

  • Default: ForeFire

NetCDFfile

  • Description: Specifies the primary NetCDF landscape file to be loaded via the loadData command if not provided directly in the command itself. If empty, loadData requires the filename argument.

  • Default: “” (Empty string)

fuelsTableFile

  • Description: Default filename for the fuel parameter table. While the default is .ff (legacy), ForeFire V2 typically expects a .csv file in practice. This file defines fuel properties (e.g., for Rothermel model).

  • Default: fuels.ff (Note: Use a `.csv` file in practice)

paramsFile

  • Description: Default filename for a file containing simulation parameters, which can be loaded via include.

  • Default: Params.ff

InitFile

  • Description: Default filename for a script file containing initial fire front state (nodes, locations) used for non-parallel starts (e.g., loaded via include).

  • Default: Init.ff

InitFiles

  • Description: Pattern for filenames containing fire front state for parallel restarts. Typically includes processor rank and time information. Example: output.0.1200 (processor 0 at time 1200).

  • Default: output

BMapsFiles

  • Description: Pattern for filenames containing pre-computed burning map data for restarts or one-way coupling.

  • Default: 1234567890 (Placeholder suggests it needs to be explicitly set)

fireOutputDirectory

  • Description: Directory where fire-related output files (e.g., front state from print, arrival maps from save) are written.

  • Default: . (Current directory)

atmoOutputDirectories

  • Description: Directory (or comma-separated list of directories for nested models) where atmospheric coupling-related outputs are written.

  • Default: . (Current directory)

outputFiles

  • Description: Base pattern for output filenames generated by ForeFire (e.g., during print or save if no filename is specified). Processor rank, variable name, and time are often appended automatically.

  • Default: output

Simulation Control & Time

parallelInit

  • Description: Boolean (0 or 1) enabling parallel initialization (restart from a previous parallel simulation state).

  • Default: 0 (Disabled)

InitTime

  • Description: Specifies the simulation time (in seconds) to use for parallel restart initialization, matching the time encoded in InitFiles. A very large default suggests it needs to be set explicitly for restarts.

  • Default: 99999999999999

Domain & Discretization

perimeterResolution

  • Description: Target maximum distance (in meters) between adjacent FireNodes discretizing the fire front. The simulation dynamically adds nodes to maintain this resolution.

  • Default: 40

spatialIncrement

  • Description: Distance (in meters) each FireNode is advanced computationally during its update step. Related to perimeterResolution via spatialCFLmax.

  • Default: 2

spatialCFLmax

  • Description: Maximum allowed ratio of spatialIncrement / perimeterResolution. Controls numerical stability and computational step size relative to front resolution.

  • Default: 0.3

normalScheme

  • Description: Algorithm used to calculate the normal vector at each FireNode (determines local spread direction). Available schemes likely include medians, weightedMedians, splines.

  • Default: medians

smoothing

  • Description: Parameter controlling the degree of smoothing applied during the calculation of the normal vector or front curvature. Affects front shape stability.

  • Default: 1

relax

  • Description: Relaxation factor used in iterative calculations, potentially for normal vector or front depth computation, to improve convergence or stability.

  • Default: 0.5

curvatureComputation

  • Description: Boolean (0 or 1) enabling/disabling the computation of local front curvature. Required by some advanced propagation models.

  • Default: 1 (Enabled)

curvatureScheme

  • Description: Algorithm used to calculate front curvature if curvatureComputation is enabled. Available schemes likely include angles, circumradius, splines.

  • Default: circumradius

frontDepthComputation

  • Description: Boolean (0 or 1) enabling/disabling the computation of fire front depth. Required by some propagation or flux models.

  • Default: 0 (Disabled)

frontDepthScheme

  • Description: Algorithm used to calculate front depth if frontDepthComputation is enabled.

  • Default: normalDir

Physics & Models

propagationModel

  • Description: Name of the Rate of Spread (ROS) model to use. ForeFire is a general solver, and this choice dictates how spread speed is calculated and what fuel parameterization is required.

  • Default: Iso

  • Available Models: The string provided must match the name of a registered C++ model class. Common supported models include: * Iso: A simple isotropic model. Does not use a fuels file. Speed is set via the Iso.speed parameter. * Rothermel: The Rothermel 1972 surface fire spread model. Requires a detailed fuel parameterization file. * BalbiNov2011, Balbi2015: Physical models from Balbi et al. Also use the fuel parameterization file.

  • More Info: See the Fuel & Model Parameterization guide for detailed explanations of each model and their data requirements.

burningTresholdFlux

  • Description: Threshold flux value (likely W/m²) used to determine if a location is considered actively burning, potentially used for front depth or flux calculations.

  • Default: 10

minimalPropagativeFrontDepth

  • Description: Minimum front depth (in meters) required for a segment of the fire front to be considered active and propagating. Below this, propagation may cease.

  • Default: 10.

maxFrontDepth

  • Description: Maximum effective front depth (in meters). If computed depth exceeds this value, its effect on propagation/flux models may be capped.

  • Default: 200.

initialFrontDepth

  • Description: Front depth (in meters) assigned to the fire front upon initialization (e.g., via startFire or FireFront/FireNode).

  • Default: 20

initialBurningDuration

  • Description: Duration (in seconds) for which the area inside the initial fire front is considered burning, relevant for flux calculations immediately after ignition. (Formerly initialBurningTime in V1).

  • Default: 30

Output, Logging & Debugging

outputsUpdate

  • Description: Frequency (in seconds) for automatically saving simulation outputs (e.g., front state via print using outputFiles pattern). Set to 0 to disable periodic automatic saving.

  • Default: 0 (Disabled)

bmapOutputUpdate

  • Description: Frequency (in seconds) for automatically saving the burning map (arrival times). Set to 0 to disable. Note: Can be computationally expensive.

  • Default: 0 (Disabled)

surfaceOutputs

  • Description: Boolean (0 or 1) enabling/disabling the output of surface properties, typically related to fluxes calculated for atmospheric coupling.

  • Default: 0 (Disabled)

debugFronts

  • Description: Boolean (0 or 1) enabling/disabling saving of detailed front state information frequently (e.g., every atmospheric step in coupled mode), mainly for debugging. Files might be overwritten.

  • Default: 0 (Disabled)

watchedProc

  • Description: Controls MPI process rank for debug outputs: * -2: No debug output from any process. * -1: Debug output from all processes. * n (>= 0): Debug output only from the process with MPI rank n.

  • Default: -2

CommandOutputs

  • Description: Boolean (0 or 1) enabling/disabling verbose debug messages related to command processing.

  • Default: 0 (Disabled)

FireDomainOutputs

  • Description: Boolean (0 or 1) enabling/disabling verbose debug messages related to the FireDomain (events, parallel operations).

  • Default: 0 (Disabled)

FireFrontOutputs

  • Description: Boolean (0 or 1) enabling/disabling verbose debug messages related to FireFront operations (topology changes, merging, splitting).

  • Default: 1 (Enabled)

FireNodeOutputs

  • Description: Boolean (0 or 1) enabling/disabling verbose debug messages related to FireNode operations (movement, speed/normal calculation).

  • Default: 1 (Enabled)

FDCellsOutputs

  • Description: Boolean (0 or 1) enabling/disabling verbose debug messages related to FDCells (flux calculations within grid cells). (Note: FDCell might be legacy or internal naming).

  • Default: 1 (Enabled)

HaloOutputs

  • Description: Boolean (0 or 1) enabling/disabling verbose debug messages related to halo regions used in parallel communication.

  • Default: 1 (Enabled)

Coupling & Grid Parameters (Often used in Coupled Mode)

atmoNX

  • Description: Number of grid cells in the X (longitude/East-West) direction for the atmospheric model grid or the grid used for flux aggregation. Often imposed by the coupled model.

  • Default: 100

atmoNY

  • Description: Number of grid cells in the Y (latitude/North-South) direction for the atmospheric model grid or flux aggregation grid. Often imposed by the coupled model.

  • Default: 100

atmoNZ

  • Description: Number of grid cells in the Z (vertical) direction for the atmospheric model grid. Often imposed by the coupled model.

  • Default: 20

refLongitude

  • Description: Reference longitude for the simulation domain origin, often imposed by a coupled atmospheric model.

  • Default: 0

refLatitude

  • Description: Reference latitude for the simulation domain origin, often imposed by a coupled atmospheric model.

  • Default: 0

year, month, day

  • Description: Reference date components for the simulation start, often imposed by a coupled atmospheric model. Combines with ISOdate.

  • Default: year=2012, month=1, day=1