WRF NAMELIST.INPUT FILE DESCRIPTION
WRF NAMELIST.INPUT FILE DESCRIPTION
The namelist.input file is used for both the real.exe and wrf.exe executables. Within the file, multiple columns are used for multiple domains (nests) and the “max_dom” parameter determines the number of domains (and nests) to use. So, for example, if you define 3 columns for parameter in the namelist but set max_dom = 2, the last column will be ignored. Note that not all parameters have multiple columns.
<WRF INSTALL DIR>/run/README.namelist contains descriptions of all the namelist variables as well as variables that can be added to the namelist for special model setups.
<WRF INSTALL DIR>/test/em_real directory contains several sample namelist.input files.
Name  Value  Description 
Time control 

run_days 
1 
run time in days 
run_hours 
0 
run time in hours 
run_minutes 
0 
run time in minutes 
0 
run time in seconds 

2001 
Four digit year of starting time 

06 
Two digit month of starting time 

11 
Two digit day of starting time 

12 
Two digit hour of starting time 

00 
Two digit minute of starting time 

00 
Two digit second of starting time. Note: the start time is used to name the first wrfout file. It also controls the start time for nest domains, and the time to restart 

2001 
Four digit year of ending time 

06 
Two digit month of ending time 

12 
Two digit day of ending time 

12 
Two digit hour of ending time 

00 
Two digit minute of ending time 

00 
Two digit second of ending time. Note all end times also control when the nest domain integrations end. All start and end times are used by real.exe. One may use either run_days/run_hours etc. or end_year/month/day/hour etc. to control the length of model integration. But run_days/run_hours takes precedence over the end times. Program real.exe uses start and end times only. 

10800 
time interval between incoming real data, which will be the interval between the lateral boundary condition file (for real only) 

.true. 
logical; whether nested run will have input files for domains other than 1 

selected fields from nest input 

0 
all fields from nest input are used 

2 
only nest input specified from input stream 2 (defined in the Registry) are used 

60 
history output file interval in minutes (integer only) 

1 
history output file interval in months (integer); used as alternative to history_interval 

1 
history output file interval in days (integer); used as alternative to history_interval 

1 
history output file interval in hours (integer); used as alternative to history_interval 

1 
history output file interval in minutes (integer); used as alternative to history_interval and is equivalent to history_interval 

1 
history output file interval in seconds (integer); used as alternative to history_interval 

1 
output times per history output file, used to split output files into smaller pieces 

whether this run is a restart run 

1440 
restart output file interval in minutes 

input from WPS (this is the default): 

2 
1 = binary format (no supported postprocessing software available) 

2 
2 = netCDF; 102 = split netCDF files one per processor (must restart with the same number of processors) 

2 
2 = NetCDF 

2 
1 = binary format (no supported postprocessing software) 

0 
0,50,100,200,300 values give increasing prints 

“rainfall_d<domain>”–file name for extra output; if not specified, auxhist2_d<domain>_<date> will be used. Also note that to write variables in output other than the history file requires Registry.EM file change 

10 
interval in minutes 

2 
output in netCDF 

nocolons 
.false. 
replace : with _ in output file names 
t 
write inputformatted data as output for 3DVAR application 

180 
interval in minutes when writing inputformatted data 

Output file name from 3DVAR 

0 
beginning year to write 3DVAR data 

0 
beginning month to write 3DVAR data 

0 
beginning day to write 3DVAR data 

3 
beginning hour to write 3DVAR data 

0 
beginning minute to write 3DVAR data 

0 
beginning second to write 3DVAR data 

0 
ending year to write 3DVAR data 

0 
ending month to write 3DVAR data 

0 
ending day to write 3DVAR data 

12 
ending hour to write 3DVAR data 

0 
ending minute to write 3DVAR data 

0 
ending second to write 3DVAR data. 

The above example shows that the inputformatted data are output starting from hour 3 to hour 12 in 180 min interval. 
domain def: dimensions, nesting params 

60 
time step for integration in integer seconds (recommended 6*dx in km for a typical case) 

0 
numerator for fractional time step 

1 
denominator for fractional time step Example, if you want to use 60.3 sec as your time step, set time_step = 60, time_step_fract_num = 3, and time_step_fract_den = 10 

1 
number of domains – set it to > 1 if it is a nested run 

1 
start index in x (westeast) direction (leave as is) 

91 
end index in x (westeast) direction (staggered dimension) 

1 
start index in y (southnorth) direction (leave as is) 

82 
end index in y (southnorth) direction (staggered dimension) 

1 
start index in z (vertical) direction (leave as is) 

28 
end index in z (vertical) direction (staggered dimension – this refers to full levels). Most variables are on unstaggered levels. Vertical dimensions need to be the same for all nests. 

40 
number of vertical levels in the incoming data: type ncdump –h to find out (WPS data only) 

1.0..0.0 
model eta levels (WPS data only). If a user does not specify this, real will provide a set of levels 

1 
use surface data as lower boundary when interpolating through this many eta levels 

5000 
p_top to use in the model 

1 
vertical interpolation; 1: linear in pressure; 2: linear in log(pressure) 

1 
vertical interpolation order; 1: linear; 2: quadratic 

.false. 
T = use surface values for the lowest eta (u,v,t,q); F = use traditional interpolation 

10000 
grid length in x direction, unit in meters 

10000 
grid length in y direction, unit in meters 

19000. 
used in mass model for idealized cases 

1 
domain identifier 

0 
id of the parent domain 

0 
starting LLC Iindices from the parent domain 

0 
starting LLC Jindices from the parent domain 

1 
parenttonest domain grid size ratio: for realdata cases the ratio has to be odd; for idealized cases, the ratio can be even if feedback is set to 0. 

1 
parenttonest time step ratio; it can be different from the parent_grid_ratio 

1 
feedback from nest to its parent domain; 0 = no feedback 

0 
smoothing option for parent domain, used only with feedback option on. 

Namelist variables for controlling the moving nest option: 

2, 
total number of moves for all domains 

2,2, 
a list of nest domain id’s, one per move 

60,120 
time in minutes since the start of this domain 

1,1, 
the number of parent domain grid cells to move in i direction 

1,1, 
the number of parent domain grid cells to move in j direction (positive in increasing i/j directions, and negative in decreasing i/j directions. The limitation now is to move only 1 grid cell at each move. 

15 
how often the new vortex position is computed 

40 
used to compute the search radius for the new vortex position 

8 
how many coarse grid cells the moving nest is allowed to get near the coarse grid boundary 

0 
number of points in tile x direction 

0 
number of points in tile y direction can be determined automatically 

1 
number of tiles per patch (alternative to above two items) 

1 
number of processors in x for decomposition 

1 
number of processors in y for decomposition 1: code will do automatic decomposition >1: for both: will be used for decomposition 
physics options 

microphysics option 

0 
no microphysics 

1 
Kessler scheme: : A warmrain (i.e. no ice) scheme used commonly in idealized cloud modeling studies. 

2 
Lin et al. scheme: a sophisticated scheme that has ice, snow and graupel processes, suitable for realdata highresolution simulations. 

3 
WRF SingleMoment (WSM) 3class simple ice scheme: A simple efficient scheme with ice and snow processes suitable for mesoscale grid sizes. 

4 
WRF SingleMoment (WSM) 5class scheme. A slightly more sophisticated version of option 3 that allows for mixedphase processes and supercooled water. This scheme has been preliminarily tested for WRFNMM. 

5 
Ferrier scheme: A scheme that includes prognostic mixedphase processes. This scheme was recently changed so that ice saturation is assumed at temperatures colder than 30C rather than 10C as in the original implementation. This scheme is well tested for WRFNMM, used operationally at NCEP. 

6 
WSM 6class graupel scheme: A new scheme with ice, snow and graupel processes suitable for highresolution simulations. This scheme has been preliminarily tested for WRFNMM. 

8 
Thompson graupel scheme: a scheme with six classes of moisture species plus number concentration for ice as prognostic variables. This scheme has been preliminarily tested for WRFNMM. 

10 
Morrison 2moment scheme 

For nonzero mp_physics options, to keep Qv >= 0, and to set the other moisture fields < a threshold value to zero 

0 
no action taken, no adjustment to any moist field 

1 
except for Qv, all other moist arrays are set to zero if they fall below a critical value 

2 
Qv is >= 0, all other moist arrays are set to zero if they fall below a critical value 

1.e8 
critical value for moisture variable threshold, below which moist arrays (except for Qv) are set to zero (unit: kg/kg) 

longwave radiation option 

0 
no longwave radiation 

1 
RRTM scheme: Rapid Radiative Transfer Model. An accurate scheme using lookup tables for efficiency. Accounts for multiple bands, trace gases, and microphysics species. This scheme has been preliminarily tested for WRFNMM. 

3 
CAM scheme 

99 
GFDL scheme: Geophysical Fluid Dynamics Laboratory (GFDL) longwave. An older version multiband, transmission table lookup scheme with carbon dioxide, ozone and water vapor absorptions. Cloud microphysics effects are included. This scheme is well tested for WRFNMM, used operationally at NCEP. 

shortwave radiation option 

0 
no shortwave radiation 

1 
Dudhia scheme: Simple downward integration allowing for efficient cloud and clearsky absorption and scattering. This scheme has been preliminarily tested for WRFNMM. 

2 
Goddard Shortwave scheme: Twostream multiband scheme with ozone from climatology and cloud effects. 

3 
CAM scheme 

99 
GFDL scheme: Geophysical Fluid Dynamics Laboratory (GFDL) shortwave. A two spectral bands, kdistribution scheme with ozone and water vapor as the main absorbing gases. Cloud microphysics effects are included. This scheme is welltested for WRFNMM, used operationally at NCEP. 

30 
minutes between radiation physics calls. Recommend 1 minute per km of dx (e.g. 10 for 10 km grid) 

1 
CO2 transmission function flag for GFDL radiation only. Set it to 1 for ARW, which allows generation of CO2 function internally 

21600 
CAM clearsky longwave absorption calculation frequency (recommended minimum value to speed scheme up) 

levsiz 
59 
for CAM radiation input ozone levels 
29 
for CAM radiation input aerosol levels 

cam_abs_dim1 
4 
for CAM absorption save array 
for CAM 2nd absorption save array 

surfacelayer option 

0 = no surfacelayer 

landsurface option (set before running real; also set correct num_soil_layers) 

0 
0 = no surface temp prediction 

1 
Thermal Diffusion scheme: soil temperature only scheme, using five layers. 

2 
Noah LandSurface Model: Unified NCEP/NCAR/AFWA scheme with soil temperature and moisture in four layers, fractional snow cover and frozen soil physics. This scheme has been preliminarily tested for WRFNMM. 

3 
RUC LandSurface Model: Rapid Update Cycle operational scheme with soil temperature and moisture in six layers, multilayer snow and frozen soil physics. This scheme has been preliminarily tested for WRFNMM. 

7  PleimXu scheme (ARW only)  
boundarylayer option 

0 = no boundarylayer 

0 
minutes between boundarylayer physics calls 

cumulus option 

0 
no cumulus 

1 
KainFritsch (new Eta) scheme: deep and shallow subgrid scheme using a mass flux approach with downdrafts and CAPE removal time scale 

2 
BettsMillerJanjic scheme: adjustment scheme for deep and shallow convection relaxing towards variable temperature and humidity profiles determined from thermodynamic considerations. 

3 
GrellDevenyi ensemble scheme: Multiclosure, multiparameter, ensemble method with typically 144 subgrid members 

4 
Simplied ArakawaSchubert (NMM only). Penetrative convection is simulated following Pan and Wu (1995), which is based on Arakawa and Schubert (1974) as simplified by Grell (1993) and with a saturated downdraft. 

5 
New Grell scheme (G3) 

99 
previous KainFritsch scheme 

0 
minutes between cumulus physics calls. For example, 10.0 minutes. 0 = call every time step 

1 
heat and moisture fluxes from the surface 

0 
snowcover effects (only works for sf_surface_physics = 1) 

1 
cloud effect to the optical depth in radiation (only works for ra_sw_physics = 1 and ra_lw_physics = 1) 

swrat_scat 
1. 
Scattering tuning parameter (default 1 is 1.e5 m2/kg) 
1,2 
where landuse and soil category data come from 

number of soil layers in land surface model (set in real) 

0 
activate urban canopy model (in Noah LSM only) (0=no, 1=yes) 

1 
GrellDevenyi only 

3 
GD only 

3 
GD only 

16 
GD only 

144 
GD only. These are recommended numbers. If you would like to use any other number, consult the code, know what you are doing. 

271. 
tsk < seaice_threshold, if water point and 5layer slab scheme, set to land point and permanent ice; if water point and Noah scheme, set to land point, permanent ice, set temps from 3 m to surface, and set smois and sh2o 

option to use timevarying SST during a model simulation (set in real) 

0 
no SST update 

1 
real.exe will create wrflowinp_d01 file at the same time interval as the available input data. To use it in wrf.exe, add auxinput5_inname = “wrflowinp_d01”, auxinput5_interval, and auxinput5_end_h in namelist section &time_control 
for grid and obs nudging 

1 
gridnudging on (=0 off) for each domain 

Defined name in real 

360 
Time interval (min) between analysis times 

6 
Time (h) to stop nudging after start of forecast 

2 
Analysis format (2 = netcdf) 

0 
Calculation frequency (in minutes) for analysis nudging. 

0 
0 = nudging in the pbl 

0 
0 = nudging in the pbl 

0 
0 = nudging in the pbl 

0 
0 = nudge u and v all layers 

10 
10 = model level below which nudging is switched off for u and v 

0 

10 
10 = model level below which nudging is switched off for temp 

0 

10 
10 = model level below which nudging is switched off for water qvapor 

0.0003 
nudging coefficient for u and v (sec1) 

0.0003 
nudging coefficient for temp (sec1) 

0.0003 
nudging coefficient for qvapor (sec1) 

0 
0= nudging ends as a step function, 1= ramping nudging down at end of period 

60. 
time (min) for ramping function, 60.0=ramping starts at last analysis time, 60.0=ramping ends at last analysis time 

(for obs nudging) 
Observation nudging 

1 
0 = obsnudging fdda off 

150000 
max number of observations used on a domain during any given time window 

0. 
obs nudging start time in minutes 

180. 
obs nudging end time in minutes 

1 
whether to nudge wind: (=0 off) 

6.e4 
nudging coefficient for wind, unit: s1 

1 
whether to nudge temperature: (=0 off) 

6.e4 
nudging coefficient for temp, unit: s1 

1 
whether to nudge water vapor mixing ratio: (=0 off) 

6.e4 
nudging coefficient for water vapor mixing ratio, unit: s1 

0 
whether to nudge surface pressure (not used) 

0. 
nudging coefficient for surface pressure, unit: s1 (not used) 

200. 
horizontal radius of influence in km 

0.1 
vertical radius of influence in eta 

0.6667 
halfperiod time window over which an observation will be used for nudging; the unit is in hours 

10 
freq in coarse grid timesteps for diag prints 

2 
freq in coarse grid timesteps for obs input and err calc 

0 
for dynamic initialization using a rampdown function to gradually turn off the FDDA before the pure forecast (=1 on) 

40. 
time period in minutes over which the nudging is ramped down from one to zero. 

.true. 
print obs input diagnostics (=.false. off) 

.true. 
.false. = don’t print obs error diagnostics 

.true. 
.false. = don’t print obs nudge diagnostics 
Diffusion, damping, advection options 

2 
dynamical core option: advanced research WRF core (Eulerian mass) 

timeintegration scheme option: 

turbulence and mixing option: 

0 
No turbulence or explicit spatial numerical filters (km_opt IS IGNORED). 

1 
Simple diffusion: evaluates 2nd order diffusion term on coordinate surfaces. uses kvdif for vertical diff unless PBL option is used. may be used with km_opt = 1 and 4. (= 1, recommended for realdata case) 

2 
Full diffusion: evaluates mixing terms in physical space (stress form) (x,y,z). turbulence parameterization is chosen by specifying km_opt. 

eddy coefficient option 

1 
Constant: K is specified by namelist values for horizontal and vertical diffusion.(use khdif and kvdif) 

2 
1.5 order TKE closure (3D) 

3 
Smagorinsky first order closure (3D) Note: option 2 and 3 are not recommended for DX > 2 km 

4 
Horizontal Smagorinsky first order closure (recommended for realdata case). K for horizontal diffusion is diagnosed from just horizontal deformation. The vertical diffusion is assumed to be done by the PBL scheme (2D) 

0 
6thorder numerical diffusion 

0.12 
6thorder numerical diffusion nondimensional rate (max value 1.0 corresponds to complete removal of 2dx wave in one timestep) 

upper level damping flag 

0 
without damping 

1 
with diffusive damping (dampcoef nondimensional ~ 0.01 – 0.1. May be used for realdata runs) 

2 
with Rayleigh damping (dampcoef inverse time scale [1/s], e.g. 0.003) 

3 
with wRayleigh damping (dampcoef inverse time scale [1/s] e.g. 0.2; for realdata cases) 

5000 
damping depth (m) from model top 

0. 
damping coefficient (see damp_opt) 

vertical velocity damping flag (for operational use) 

0 
without damping 

1 
with damping 

100000. 
Base state surface pressure (Pa), real only. Do not change. 

290. 
Base state sea level temperature (K), real only. 

50. 
realdata ONLY, lapse rate (K), DO NOT CHANGE. 

0 
horizontal diffusion constant (m^2/s) 

0 
vertical diffusion constant (m^2/s) 

0.1 
divergence damping (0.1 is typical) 

0.01 
externalmode filter coef for mass coordinate model (0.01 is typical for realdata cases) 

.1 
time offcentering for vertical sound waves 

.true. 
whether running the model in hydrostatic or nonhydro mode 

.false. 
Coriolis only acts on wind perturbation (idealized) 

.false. 
For diff_opt=2 only, vertical diffusion acts on full fields (not just on perturbation from 1D base_ profile) (idealized) 

5 
horizontal momentum advection order (5=5th, etc.) 

3 
vertical momentum advection order 

5 
horizontal scalar advection order 

3 
vertical scalar advection order 

4 
number of sound steps per timestep (if using a time_step much larger than 6*dx (in km), increase number of sound steps). = 0: the value computed automatically 

.false. 
positive define advection of moisture; set to .true. to turn it on 

.false. 
positive define advection of scalars 

.false. 
positive define advection of tke 

.false. 
positive define advection of chem vars 

0 
surface drag coefficient (Cd, dimensionless) for diff_opt=2 only 

0 
surface thermal flux (H/rho*cp), K m/s) for diff_opt = 2 only 
boundary condition control 

5 
total number of rows for specified boundary value nudging 

1 
number of points in specified zone (spec b.c. option) 

4 
number of points in relaxation zone (spec b.c. option) 

.false. 
specified boundary conditions (only can be used for to domain 1) 

The above 4 namelists are used for realdata runs only 

.false. 
periodic boundary conditions in x direction 

.false. 
symmetric boundary conditions at x start (west) 

.false. 
symmetric boundary conditions at x end (east) 

.false. 
open boundary conditions at x start (west) 

.false. 
open boundary conditions at x end (east) 

.false. 
periodic boundary conditions in y direction 

.false. 
symmetric boundary conditions at y start (south) 

.false. 
symmetric boundary conditions at y end (north) 

.false. 
open boundary conditions at y start (south) 

.false. 
open boundary conditions at y end (north) 

.false. 
nested boundary conditions (must be set to .true. for nests) 
Option for async I/O for MPI apps 

0 
default value is 0: no quilting; > 0 quilting I/O 

1 
default 1 
Grib2 

255 
Background generating process identifier, typically defined by the originating center to identify the background data that was used in creating the data. This is octet 13 of Section 4 in the grib2 message 

255 
Analysis or generating forecast process identifier, typically defined by the originating center to identify the forecast process that was used to generate the data. This is octet 14 of Section 4 in the grib2 message 

255 
Production status of processed data in the grib2 message. See Code Table 1.3 of the grib2 manual. This is octet 20 of Section 1 in the grib2 record 

40 
The compression method to encode the output grib2 message. Only 40 for jpeg2000 or 41 for PNG are supported 