Difference between revisions of "SFIRE variables"

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Line 51: Line 51:
 
| J/m<sup>2</sup>
 
| J/m<sup>2</sup>
 
| heat flux from the ground fire
 
| heat flux from the ground fire
 +
|}
 +
 +
 +
{| border="1"
 +
|+ Fire variables on fire grid
 +
! scope="col" | Variable name
 +
! scope="col" | Dimensions
 +
! scope="col" | Stagger
 +
! scope="col" | IO
 +
! scope="col" | Description
 +
! scope="col" | Unit
 +
|-
 +
! scope="row" | NFUEL_CAT
 +
|*i*j
 +
|z
 +
|i012hr
 +
|fuel data
 +
|
 +
|-
 +
! scope="row" | ZSF
 +
|*i*j
 +
|z
 +
|i012hr
 +
|height of surface above sea level
 +
|m
 +
|-
 +
! scope="row" | DZDXF
 +
|*i*
 +
|z
 +
| i012hr
 +
|surface gradient x
 +
|1
 +
|-
 +
! scope="row" | DZDYF
 +
|*i*j
 +
|z
 +
| i012hr
 +
|surface gradient y
 +
|1
 +
|}
 +
 +
 +
{| border="1"
 +
|+Fire variables on atm grid (outputs to atm model)
 +
! scope="col" | Variable name
 +
! scope="col" | Dimensions
 +
! scope="col" | Stagger
 +
! scope="col" | IO
 +
! scope="col" | Description
 +
! scope="col" | Unit
 +
|-
 +
! scope="row" | RTHFRTEN
 +
|ikj
 +
|z
 +
|hr 
 +
|temperature tendency
 +
|K/s
 +
|-
 +
! scope="row" | RQVFRTEN
 +
|ikj
 +
|z
 +
|hr
 +
|humidity tendency
 +
|
 +
|}
 +
 +
 +
{| border="1"
 +
|+Diagnostics
 +
! scope="col" | Variable name
 +
! scope="col" | Dimensions
 +
! scope="col" | Stagger
 +
! scope="col" | IO
 +
! scope="col" | Description
 +
! scope="col" | Unit
 +
|-
 +
! scope="row" | AVG_FUEL_FRAC
 +
|ij
 +
|z
 +
|hr
 +
|fuel remaining averaged to atmospheric grid
 +
|1
 +
|-
 +
! scope="row" | GRNHFX
 +
|ij
 +
|z
 +
|hr
 +
|heat flux from ground fire
 +
|W/m^2
 +
|-
 +
! scope="row" | GRNQFX
 +
|ij
 +
|z
 +
|hr
 +
|moisture flux from ground fire
 +
|W/m^2
 +
|-
 +
! scope="row" | CANHFX
 +
|ij
 +
|z
 +
|hr
 +
|heat flux from crown fire
 +
|W/m^2
 +
|-
 +
! scope="row" | CANQFX
 +
|ij
 +
|z
 +
|hr
 +
|moisture flux from crown fire
 +
|W/m^2
 +
|-
 +
! scope="row" | UAH
 +
|ij
 +
|X
 +
|hr
 +
|wind at fire_wind_heigh
 +
|m/s
 +
|-
 +
! scope="row" | VAH
 +
|ij
 +
|Y
 +
|hr
 +
|wind at fire_wind_heigh
 +
|m/s
 +
|}
 +
 +
 +
{| border="1"
 +
|+Sfire variables on fire grid(also using inputs: zs,z_at_w,dz8w,nfuel_cat,zsf)
 +
! scope="col" | Variable name
 +
! scope="col" | Dimensions
 +
! scope="col" | Stagger
 +
! scope="col" | IO
 +
! scope="col" | Description
 +
! scope="col" | Unit
 +
|-
 +
! scope="row" | TIGN_G
 +
|*i*j
 +
|z
 +
|i102hr
 +
|ignition time on ground
 +
|s
 +
|-
 +
! scope="row" | LFN
 +
|*i*j
 +
|z
 +
|i102hr
 +
|level function
 +
|1
 +
|-
 +
! scope="row" | FUEL_FRAC
 +
|*i*j
 +
|z
 +
|i102hr
 +
|fuel remaining
 +
|1
 +
|-
 +
! scope="row" | FMC_G
 +
|*i*j
 +
|z
 +
|i102hr
 +
|fuel moisture contents
 +
|1
 +
|-
 +
! scope="row" | FIRE_AREA
 +
|*i*j
 +
|z
 +
|hr
 +
|fraction of cell area on fire
 +
|1
 +
|-
 +
! scope="row" | UF
 +
|*i*j
 +
|z
 +
|hr
 +
|fire wind
 +
|m/s
 +
|-
 +
! scope="row" | VF
 +
|*i*j
 +
|z
 +
|hr
 +
|fire wind
 +
|m/s
 +
|-
 +
! scope="row" | FGRNHFX
 +
|*i*j
 +
|z
 +
|hr
 +
|heat flux from ground fire
 +
|W/m^2
 +
|-
 +
! scope="row" | FGRNQFX
 +
|*i*j
 +
|z
 +
|hr
 +
|moisture flux from ground fire
 +
|W/m^2
 +
|-
 +
! scope="row" | FCANHFX
 +
|*i*j
 +
|z
 +
|hr
 +
|heat flux from crown fire
 +
|W/m^2
 +
|-
 +
! scope="row" | FCANQFX
 +
|*i*j
 +
|z
 +
|hr
 +
|moisture flux from crown fire
 +
|W/m^2
 +
|}
 +
 +
 +
{| border="1"
 +
|+Diagnostics for the actual modeled fire
 +
! scope="col" | Variable name
 +
! scope="col" | Dimensions
 +
! scope="col" | Stagger
 +
! scope="col" | IO
 +
! scope="col" | Description
 +
! scope="col" | Unit
 +
|-
 +
! scope="row" | ROS
 +
|*i*j
 +
|z
 +
|hr
 +
|rate of spread in the normal direction to the fireline
 +
|m/s
 +
|-
 +
! scope="row" | FLINEINT
 +
|*i*j
 +
|z
 +
|hr
 +
|fireline intensity
 +
|W/m
 +
|-
 +
! scope="row" | FLINEINT2
 +
|*i*j
 +
|z
 +
|hr
 +
|alternative fireline intensity
 +
|J/m/s^2
 +
|}
 +
 +
{| border="1"
 +
|+Diagnostics for fire risk rating - independent on any actual fire going on
 +
! scope="col" | Variable name
 +
! scope="col" | Dimensions
 +
! scope="col" | Stagger
 +
! scope="col" | IO
 +
! scope="col" | Description
 +
! scope="col" | Unit
 +
|-
 +
! scope="row" | F_ROS0
 +
|*i*j
 +
|z
 +
|hr
 +
|base rate of spread in all directions
 +
|m/s
 +
|-
 +
! scope="row" | F_ROSX
 +
|*i*j
 +
|z
 +
|hr
 +
|X component of the spread vector driven by wind and slope
 +
|m/s
 +
|-
 +
! scope="row" | F_ROSY
 +
|*i*j
 +
|z
 +
|hr
 +
|Y component of the spread vector driven by wind and slope
 +
|m/s
 +
|-
 +
! scope="row" | F_ROS
 +
|*i*j
 +
|z
 +
|hr
 +
|max spread rate in any direction
 +
|m/s
 +
|-
 +
! scope="row" | F_INT
 +
|*i*j
 +
|z
 +
|hr
 +
|fire reaction intensity for risk rating, without fire
 +
|J/m^2/s
 +
|-
 +
! scope="row" | F_LINEINT
 +
|*i*j
 +
|z
 +
|hr
 +
|Byram fireline intensity for risk rating, without fire
 +
|J/m/s
 +
|-
 +
! scope="row" | F_LINEINT2
 +
|*i*j
 +
|z
 +
|hr
 +
|alternative fireline intensity for risk rating, without fire"
 +
|J/m/s^2
 +
|}
 +
 +
 +
{| border="1"
 +
|+Constant data arrays
 +
! scope="col" | Variable name
 +
! scope="col" | Dimensions
 +
! scope="col" | Stagger
 +
! scope="col" | IO
 +
! scope="col" | Description
 +
! scope="col" | Unit
 +
|-
 +
! scope="row" | FXLONG
 +
|*i*j
 +
|z
 +
|ihr
 +
|longitude of midpoints of fire cells
 +
|degrees
 +
|-
 +
! scope="row" |FXLAT
 +
|*i*j
 +
|z
 +
|ihr
 +
|latitude of midpoints of fire cells
 +
|degrees
 +
|-
 +
! scope="row" |FUEL_TIME
 +
|*i*j
 +
|z
 +
|hr
 +
|fuel
 +
|
 +
|-
 +
! scope="row" |BBB
 +
|*i*j
 +
|z
 +
|hr
 +
|fuel
 +
|
 +
|-
 +
! scope="row" |PHISC
 +
|*i*j
 +
|z
 +
|hr
 +
|fuel
 +
|
 +
|-
 +
! scope="row" |PHIWC
 +
|*i*j
 +
|z
 +
|hr
 +
|fuel
 +
|
 +
|-
 +
! scope="row" |R_0
 +
|*i*j
 +
|z
 +
|hr
 +
|fuel
 +
|
 +
|-
 +
! scope="row" |FGIP
 +
|*i*j
 +
|z
 +
|hr
 +
|fuel
 +
|
 +
|-
 +
! scope="row" |FZ0
 +
|*i*j
 +
|z
 +
|hr
 +
|fuel roughness height
 +
|
 +
|-
 +
! scope="row" |FWH
 +
|*i*j
 +
|z
 +
|hr
 +
|fuel fire wind height
 +
|
 +
|-
 +
! scope="row" |ISCHAP
 +
|*i*j
 +
|z
 +
|hr
 +
|fuel
 +
|
 
|}
 
|}

Revision as of 21:48, 26 September 2011

Back to the WRF-SFIRE user guide.

Introduction

Firemesh.png

The fire mesh is 2D. Every atmosphere cell is divided into sr_x by sr_y fire cells. The submesh ratios sr_x and sr_y are specified in the file namelist.input. These values are not stored in the NetCDF files, but can be computed from the dimension sizes. 

sr_x=west_east_subgrid/west_east_stag = west_east_subgrid/(west_east + 1)
sr_y=south_north_subgrid/south_north_stag = south_north_subgrid/(south_north + 1)

For historical reasons, the fire grid dimensions in the output files are larger than what is actually used by the code internally. The extra space is at the end of the variables of size sr_x in x and sr_y in y. The following is an example of python code for correctly reading FGRNHFX from the file wrfout. 

from netCDF4 import Dataset
f=Dataset('wrfout','r')
sr_x=len(f.dimensions['west_east_subgrid'])/(len(f.dimensions['west_east'])+1)
sr_y=len(f.dimensions['south_north_subgrid'])/(len(f.dimensions['south_north'])+1)
fgrnhfx=f.variables['FGRNHFX']
fgrnhfx=fgrnhfx[...,:-sr_y,:-sr_x]

Variables on the fire mesh are located at the centers of the fire mesh cells of a 2D fire mesh.

List of variables

The authoritative information can be always found in the Registry.

State

Variable name Unit Description
FXLONG, FXLAT degrees (real) longitude and latitude of the nodes (centers of the fire mesh)
1 (ideal) mesh coordinates of the nodes; lower left is (0.5,0.5)

Diagnostics

Variable name Unit Description
FGRNHFX J/m2 heat flux from the ground fire


Fire variables on fire grid
Variable name Dimensions Stagger IO Description Unit
NFUEL_CAT *i*j z i012hr fuel data
ZSF *i*j z i012hr height of surface above sea level m
DZDXF *i* z i012hr surface gradient x 1
DZDYF *i*j z i012hr surface gradient y 1


Fire variables on atm grid (outputs to atm model)
Variable name Dimensions Stagger IO Description Unit
RTHFRTEN ikj z hr temperature tendency K/s
RQVFRTEN ikj z hr humidity tendency


Diagnostics
Variable name Dimensions Stagger IO Description Unit
AVG_FUEL_FRAC ij z hr fuel remaining averaged to atmospheric grid 1
GRNHFX ij z hr heat flux from ground fire W/m^2
GRNQFX ij z hr moisture flux from ground fire W/m^2
CANHFX ij z hr heat flux from crown fire W/m^2
CANQFX ij z hr moisture flux from crown fire W/m^2
UAH ij X hr wind at fire_wind_heigh m/s
VAH ij Y hr wind at fire_wind_heigh m/s


Sfire variables on fire grid(also using inputs: zs,z_at_w,dz8w,nfuel_cat,zsf)
Variable name Dimensions Stagger IO Description Unit
TIGN_G *i*j z i102hr ignition time on ground s
LFN *i*j z i102hr level function 1
FUEL_FRAC *i*j z i102hr fuel remaining 1
FMC_G *i*j z i102hr fuel moisture contents 1
FIRE_AREA *i*j z hr fraction of cell area on fire 1
UF *i*j z hr fire wind m/s
VF *i*j z hr fire wind m/s
FGRNHFX *i*j z hr heat flux from ground fire W/m^2
FGRNQFX *i*j z hr moisture flux from ground fire W/m^2
FCANHFX *i*j z hr heat flux from crown fire W/m^2
FCANQFX *i*j z hr moisture flux from crown fire W/m^2


Diagnostics for the actual modeled fire
Variable name Dimensions Stagger IO Description Unit
ROS *i*j z hr rate of spread in the normal direction to the fireline m/s
FLINEINT *i*j z hr fireline intensity W/m
FLINEINT2 *i*j z hr alternative fireline intensity J/m/s^2
Diagnostics for fire risk rating - independent on any actual fire going on
Variable name Dimensions Stagger IO Description Unit
F_ROS0 *i*j z hr base rate of spread in all directions m/s
F_ROSX *i*j z hr X component of the spread vector driven by wind and slope m/s
F_ROSY *i*j z hr Y component of the spread vector driven by wind and slope m/s
F_ROS *i*j z hr max spread rate in any direction m/s
F_INT *i*j z hr fire reaction intensity for risk rating, without fire J/m^2/s
F_LINEINT *i*j z hr Byram fireline intensity for risk rating, without fire J/m/s
F_LINEINT2 *i*j z hr alternative fireline intensity for risk rating, without fire" J/m/s^2


Constant data arrays
Variable name Dimensions Stagger IO Description Unit
FXLONG *i*j z ihr longitude of midpoints of fire cells degrees
FXLAT *i*j z ihr latitude of midpoints of fire cells degrees
FUEL_TIME *i*j z hr fuel
BBB *i*j z hr fuel
PHISC *i*j z hr fuel
PHIWC *i*j z hr fuel
R_0 *i*j z hr fuel
FGIP *i*j z hr fuel
FZ0 *i*j z hr fuel roughness height
FWH *i*j z hr fuel fire wind height
ISCHAP *i*j z hr fuel
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