1. WRF Tutorial For Version 2.2 / Synoptic Lab 10/3/2007 Robert Fovell or

2. Background on WRF model
“Weather Research and Forecasting”
Co-developed by research and operational communities
ARW core “Advanced Research WRF”
NMM core “Nonhydrostatic Mesoscale Model”
Supercedes MM5 and Eta models
Current version 2.2
Platforms include Linux and Mac OS X

3. WRF advantages Better numerics than MM5
Arakawa C grid, R-K scheme, odd order advection w/ implicit diffusion
Much less diffusive, larger effective resolution, permits longer time steps
Better handling of topography than Eta (original NAM)
NAM model is now WRF-NMM
Fortran 95 (MM5 was F77)
NetCDF, GRIB1 and GRIB2

4. Further advantages MPI from the ground up
Allows real data and idealized simulations in same framework
Plug-in architecture (different groups will supply WRF “cores”)
Recently added: moving nests and nudging
NetCDF output - many great tools such as NetCDF operators:
Examples here ??

5. WRF disadvantages Bleeding edge
Smaller range of physics choices (tho more modern)
Software design is unintuitive for physical scientists
Can take hours to compile
But does not need frequent recompiling
Comparatively slower than MM5
NetCDF files can be huge

6. WRF and related software
WRF Preprocessing System (WPS)
Replaces/supercedes WRF SI
WRF-ARW model
Single node and MPI
WRF postprocessing software
RIP (read/interpolate/plot)
GrADS
Specific to “hurricane” Synoptic Lab environment
Neglecting for now: GRIB2, ARWpost

7. Web resources WRF model users site ARW users’ guide
ARW users’ guide
WRF-ARW/WPS online tutorial
WRF namelist description
Tutorial presentations

8. My resources
This presentation (PPT format)
WRF on Mac OS X

9. Setup on “hurricane” machines
Presumed:
• tcsh environment
• Intel Fortran compiler (64-bit)
• my environment setup employed
• precompiled versions of WRF, WPS, RIP and wrf_to_grads

10. Environment setup > …is the command line prompt
If you don’t have a .cshrc file (worth saving) - recommended
> cp /home/fovell/.cshrc .
> source .cshrc
If you want to keep your present .cshrc
> cp /home/fovell/cshrc_fovell.csh .
> ./cshrc_fovell.csh
[you need to have the compiler environment set up already]

11. This environment uses my versions of
# RGF additions [abridged]
setenv RIP_ROOT /home/fovell/RIP4
setenv GADDIR /home/fovell/lib/grads
setenv GASCRP /home/fovell/gradslib #
alias lsm 'ls -alt | more'
alias rm 'rm -i'
alias cp 'cp -i'
alias mv 'mv -i'
alias trsl ' tail -f rsl.out.0000'
alias mpirun 'nohup time /home/fovell/mpich-1.2.7p1/bin/mpirun'
alias w2g '/home/fovell/WRF2GrADS/wrf_to_grads'
setenv P4_GLOBMEMSIZE
setenv P4_SOCKBUFSIZE 65536
unlimit
limit coredumpsize 0
This environment uses my versions of
netcdf, mpich, grads, RIP

12. Set up a run directory > cd > mkdir FELIX > cd FELIX
> cp /home/fovell/WRFtutorial/make_all_links.csh .
> make_all_links.csh
> cp /home/fovell/WRFtutorial/namelist.* .
[copies namelist.input, namelist.wps]

13. WRF for real-data run Hurricane Felix (2007)
[This example uses data that
will not remain online]

14. WPS overview Tasks Controlled by namelist.wps
(1) set up a domain (can be reused)
geogrid.exe
(2) unpack parent model data (e.g., from GFS, NAM, etc.)
ungrib.exe
(3) prepare unpacked data for WRF
metgrid.exe
Controlled by namelist.wps

15. namelist.wps
&share
wrf_core = 'ARW',
max_dom = 1,
start_date = ' _00:00:00',' _00:00:00',
end_date = ' _12:00:00',' _12:00:00',
interval_seconds = 10800,
io_form_geogrid = 2, /
For start_date, end_date need one column for each domain
interval_seconds is parent model data frequency (here, 3 h)

16. namelist.wps (cont.) &geogrid there is more… parent_id = 1, 1,
parent_grid_ratio = 1, 3,
i_parent_start = 1, 53,
j_parent_start = 1, 65,
e_we = 70, 259,
e_sn = 40, 199
geog_data_res = '2m','2m',
dx = 36000,
dy = 36000,
map_proj = 'lambert',
ref_lat = 15.0
ref_lon = -75.0,
truelat1 = 29.6,
truelat2 = 29.6,
stand_lon = -75.0,
geog_data_path = '/home/fovell/WPS_GEOG/geog' /
there is more…

17. geogrid - create domain
> geogrid.exe
* creates geo_em.d01.nc (a NetCDF file)
* look for “Successful completion of geogrid.”
> plotgrids.exe
* creates gmeta
> idt gmeta
* uses NCAR graphics tool to view domain

18. ‘gmeta’ file

19. > ncdump geo_em.d01.nc | more
netcdf geo_em.d01 {
dimensions:
Time = UNLIMITED ; // (1 currently)
DateStrLen = 19 ;
west_east = 69 ;
south_north = 39 ;
south_north_stag = 40 ;
west_east_stag = 70 ;
land_cat = 24 ;
soil_cat = 16 ;
month = 12 ;
variables:
char Times(Time, DateStrLen) ;
float XLAT_M(Time, south_north, west_east) ;
XLAT_M:FieldType = 104 ;
XLAT_M:MemoryOrder = "XY " ;
XLAT_M:units = "degrees latitude" ;
XLAT_M:description = "Latitude on mass grid" ;
XLAT_M:stagger = "M" ;

20. Parent model data issues
Sources include GFS, NAM, NARR reanalysis data, etc.
Need a different Vtable (variable table) for each source
e.g., Vtable.GFS, Vtable.AWIP (NAM), Vtable.NARR, etc.
Look in /home/fovell/WRFtutorial

21. Accessing parent model data
> link_grib.csh /home/fovell/ /gfs
* links to where parent model for case resides
** data files start with ‘gfs*’
> ln -sf /home/fovell/WRFtutorial/Vtable.GFS Vtable
* specifies appropriate Vtable
> ungrib.exe
* extracts parent model data
* look for “Successful completion of ungrib.”

22. Next step: metgrid > metgrid.exe ...hopefully you see ...
“Successful completion of metgrid.”
...Output looks like...
met_em.d _00:00:00.nc met_em.d _21:00:00.nc
met_em.d _03:00:00.nc met_em.d _00:00:00.nc
met_em.d _06:00:00.nc met_em.d _03:00:00.nc
met_em.d _09:00:00.nc met_em.d _06:00:00.nc
met_em.d _12:00:00.nc met_em.d _09:00:00.nc
met_em.d _15:00:00.nc met_em.d _12:00:00.nc
met_em.d _18:00:00.nc

23. ncdump on a metgrid file
netcdf met_em.d _00:00:00 {
dimensions:
Time = UNLIMITED ; // (1 currently)
DateStrLen = 19 ;
west_east = 69 ;
south_north = 39 ;
num_metgrid_levels = 27 ;
num_sm_levels = 4 ;
num_st_levels = 4 ;
south_north_stag = 40 ;
west_east_stag = 70 ;
z-dimension0012 = 12 ;
z-dimension0016 = 16 ;
z-dimension0024 = 24 ;
This data source has 27 vertical levels.
This will vary with source.

24. WRF model steps Tasks Both use namelist.input
Run real.exe (to finish creation of WRF model input data)
Run wrf.exe
Both use namelist.input
Configured separately from namelist.wps but includes overlapping information

25. For start_*, end_*, one column per domain
namelist.input
&time_control
run_days = 0,
run_hours = 36,
run_minutes = 0,
run_seconds = 0,
start_year = , 2007 ,
start_month = 09 , 09 ,
start_day = 02 , 02 ,
start_hour = 00 , 00 ,
start_minute = 00, 00,
start_second = 00, 00,
end_year = , 2007 ,
end_month = 09 , 09 ,
end_day = 03 , 03 ,
end_hour = 12 , 12 ,
end_minute = 00, 00,
end_second = 00, 00,
For start_*, end_*, one column per domain

26. namelist.input (cont.) interval_seconds matches namelist.wps
input_from_file = .true., .true.,
history_interval = 60, 60,
frames_per_outfile = 6, 6,
restart = .false.,
restart_interval = 5000,
interval_seconds matches namelist.wps
input_from_file should normally be ‘true’ for each domain
history_interval - how frequently (in min) output created
frames_per_outfile - number of writes in each history file
If wish to restart mode, restart = .true.
(and set model start_* data to restart time)
restart_interval = frequency (min) for writing restart files

27. namelist.input (cont.) time_step = 150, time_step_fract_num = 0,
&domains
time_step = 150,
time_step_fract_num = 0,
time_step_fract_den = 1,
max_dom = 1,
s_we = 1, 1, 1,
e_we = 70, , 94,
s_sn = 1, 1, 1,
e_sn = 40, , 91,
s_vert = 1, 1, 1,
e_vert = 31, 31, 31,
num_metgrid_levels = 27
dx = 36000, 12000, 333,
dy = 36000, 12000, 333,
grid_id = 1, 2, 3,
parent_id = 0, 1, 2,
i_parent_start = 0, , 30,
j_parent_start = 0, , 30,
parent_grid_ratio = 1, 3, 3,
parent_time_step_ratio = 1, 3, 3,

28. namelist.input (cont.) mp_physics [Microphysics] = 1 , 1 ,
ra_lw_physics [Longwave rad] = 1 , 1 ,
ra_sw_physics [Shortwave rad] = 1 , 1 ,
radt [Radiation time step; min] = 10 , 10 ,
sf_sfclay_physics [Surface layer] = 1 , 1 ,
sf_surface_physics [Surface] = 1 , 1 ,
bl_pbl_physics [Boundary layer] = 1 , 1 ,
bldt [Boundary layer time step; min]= 0, 0,
cu_physics [cumulus scheme] = 1 , 0 ,
cudt [cumulus time step; min] = 5 ,
isfflx = 1,
ifsnow = 0,
icloud = 1,
surface_input_source = 1,
num_soil_layers = 5 ,
mp_zero_out = 0 ,

29. Notes on physics
Need to use SAME microphysics (mp) scheme in each domain, but can use different cumulus (cu) schemes
Some physics combinations work better than others, some don’t work at all -- this is only lightly documented
bldt = 0 means boundary layer scheme is called every time step

30. namelist.input (cont.)
&dynamics
w_damping = 0,
diff_opt [subgrid turbulence] = 1,
km_opt [ “ ] = 4,
diff_6th_opt [numerical smoothing] = 0,
diff_6th_factor [ “ ] = 0.12,
base_temp = 290.
damp_opt = 0,
zdamp = 5000., , ,
dampcoef = 0.01, ,
khdif = 0, , ,
kvdif = 0, , ,
Only some diff_opt/km_opt combinations make sense,
and choices are resolution-dependent.
More info:

32. real.exe Has changed a lot since version 2.1.2
Number of vertical model levels now specified w/ real.exe
The num_metgrid_levels comes from parent model; you set e_vert (number of WRF levels) here
Can reset WRF levels by rerunning real.exe
Can also specify which levels you want
e_vert = 31, 31, 31,
num_metgrid_levels = 27

33. Setting levels in namelist.input (optional)
WRF uses “sigma” or “eta” coordinates (1.0 is model
bottom, 0.0 is top)
Added lines to &domains in namelist.input, presuming
e_vert = 51, requests a model top pressure of 50 mb
(5000 Pa) and concentrates vertical resolution in lower trop
p_top_requested = 5000
eta_levels = 1.00,0.9969,0.9935,0.9899,0.9861,0.9821,
0.9777,0.9731,0.9682,0.9629,0.9573,0.9513,
0.9450,0.9382,0.9312,0.9240,0.9165,0.9088,
0.9008,0.8925,0.8840,0.8752,0.8661,0.8567,
0.8471,0.8371,0.8261,0.8141,0.8008,0.7863,0.7704,
0.7531,0.7341,0.7135,0.6911,0.6668,0.6406,
0.6123,0.5806,0.5452,0.5060,0.4630,0.4161,
0.3656,0.3119,0.2558,0.1982,0.1339,0.0804,0.0362,0.0000,

34. Run real.exe > mpirun -np 2 real.exe
password:
starting wrf task of
starting wrf task of
2.624u 1.248s 0: % k 0+0io 0pf+0w
> tail rsl.out.0000
--> extrapolating TEMPERATURE near sfc: i,j,psfc, p target
d _12:00:00 forcing artificial silty clay loam
LAND CHANGE =
WATER CHANGE =
d _12:00:00 Timing for processing s.
LBC valid between these times _09:00: _12:00:00
d _12:00:00 Timing for output s.
d _12:00:00 Timing for loop # 13 = s.
d _12:00:00 real_em: SUCCESS COMPLETE REAL_EM INIT

35. Aside: password-less execution
Last slide’s mpirun command asked for 2 cpus (-np 2)
By default, 2 cpus on same workstation are accessed
To avoid being asked for password:
> cd ~/.ssh
> ssh-keygen -t dsa [then hit return 4 times]
Your public key has been saved in /home/wrf/.ssh/id_dsa.pub.
The key fingerprint is:
cc:78:50:1e:77:23:ca:8f:81:3d:f0:d2:a4:8a:2e:a7
> cp id_dsa.pub authorized_keys [if does not already exist]
> cd ../FELIX

36. Run wrf.exe
Output of real.exe is wrfbdy_d01 and wrfinput_d01 (NetCDF files)
Additional wrfinput files created for nests if max_dom > 1
Run the model
> mpirun -np 4 wrf.exe &
• Creates wrfout_d01* files keyed by simulation date, and rsl.out/rsl.error files for each CPU requested

37. FELIX output Namelist set up to do 36 h run
Look for at end of rsl.out.0000 file:
d _12:00:00 wrf: SUCCESS COMPLETE WRF
Output files created:
This is because history_interval was 60 min and frames_per_outfile was 6
wrfout_d01_ _00:00:00 wrfout_d01_ _00:00:00
wrfout_d01_ _06:00:00 wrfout_d01_ _06:00:00
wrfout_d01_ _12:00:00 wrfout_d01_ _12:00:00
wrfout_d01_ _18:00:00

38. Postprocessing WRF output: RIP and GrADS (Vis5D and ARWpost also exist)

39. RIP RIP operates in batch mode, using input scripts
RIP can overlay fields, do arbitrary cross-sections, calculate trajectories, and create Vis5D output files
RIP tasks include
Unpack model output data (ripdp_wrf)
Create RIP plotting scripts (rip.in files)
Execute scripts (rip)
RIP can create a LOT of output files

40. RIP procedure > ripdp_wrf run1 all wrfout_d01*
[this creates a new dataset called ‘run1’
and uses all wrfout_d01 files created]
> rip run1 rip.T2.in
[the rip.T2.in file is a script containing
RIP plotting commands]
[the output file, rip.T2.cgm, is a graphics
metafile]
> You can view the cgm file using idt or ictrans

41. 36 h forecast (2 m T - color; SLP - contour; 10 m winds - vector)

42. RIP script http://www.mmm.ucar.edu/mm5/documents/ripug_V4.html
===========================================================================
feld=T2; ptyp=hc; vcor=s; levs=1fb; cint=0.5; cmth=fill;>
arng; cbeg=283; cend=309; cosq=0,violet,12.5,blue,25,green,37.5,>
light.green,50,white,62.5,yellow,75,orange,87.5,red,100,brown
feld=U10,V10; ptyp=hv; vcmx=20.0; colr=black; linw=1; intv=2;
feld=slp; ptyp=hc; vcor=s; levs=1fb; cint=4; nohl;colr=blue;linw=2;nolb
feld=map; ptyp=hb; colr=dark.blue; linw=2;
feld=tic; ptyp=hb

43. GrADS and wrf_to_grads
GrADS produces beautiful graphics
Batch scriptable AND interactive
Interactive: good for overlaying different datasets, computing difference fields [can also be done in RIP]
Doesn’t create huge numbers of intermediate files like RIP
Arbitrary cross-sections are very difficult to construct

44. GrADS procedure
Copy control_file from /home/fovell/WRFtutorial and edit
Select variables desired and define wrfout files to be accessed (next slide)
w2g control_file run1g
Creates run1g.ctl, run1g.dat

45. List of available 2D fields follows
control_file
! times to put in GrADS file, negative ignores this
_00:00:00
_00:05:00
_00:10:00
end_of_time_list
! 3D variable list for GrADS file
! indent one space to skip
U ! U Compoment of wind
V ! V Component of wind
UMET ! U Compoment of wind - rotated (diagnostic)
VMET ! V Component of wind - rotated (diagnostic)
W ! W Component of wind
THETA ! Theta
TK ! Temperature in K
TC ! Temperature in C
List of available 2D fields follows

46. control_file (cont.) ! Now we check to see what to do with the data
! All list of files to read here
! Indent not to read
! Full path OK
wrfout_d01_ _00:00:00
wrfout_d01_ _06:00:00
wrfout_d01_ _12:00:00
wrfout_d01_ _18:00:00
wrfout_d01_ _00:00:00
wrfout_d01_ _06:00:00
wrfout_d01_ _12:00:00
end_of_file_list
! Now we check to see what to do with the data
real ! real (input/output) / ideal / static
! 0=no map background in grads, 1=map background in grads
! specify grads vertical grid
! 0=cartesian,
! -1=interp to z from lowest h
! 1 list levels (either height in km, or pressure in mb)
1000.0
950.0
900.0
850.0
800.0
750.0

47. Running GrADS > gradsnc -l [GrADS graphics output window opens]
ga-> open run1g
[ga-> is GrADS environment prompt]
ga-> /home/fovell/WRFtutorial/T2_movie.gs
[executes this GrADS script;
hit return to advance a frame]
ga-> quit
[to exit]

48. 36 h forecast (2 m T and 10 m winds)

49. = end =