Transcript Document
WRF Tutorial For Version 3.0.1.1 / Synoptic Lab January, 2009
Robert Fovell [email protected]
http://www.atmos.ucla.edu/~fovell/WRF/wrf_tutorial_2009.ppt.htm
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 3.0.1.1
• Platforms include Linux and Mac OS X
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 and C (MM5 was F77) • NetCDF, GRIB1 and GRIB2
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: http://nco.sourceforge.net/ • GRIB2 output now possible as well
WRF disadvantages
• Bleeding edge • Smaller range of physics choices (changing quickly…) • 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
WRF and related software
• WRF Preprocessing System (WPS) – Replaces/supercedes WRF SI • WRF-ARW model – Single node, OpenMP and MPI • WRF postprocessing software – RIP (read/interpolate/plot) – GrADS – NCL • Specific to “hurricane” Synoptic Lab environment • Neglecting for now: ARWpost, WRF Chem, WRF Var, MET (Verification software), VAPOR, Vis5D
Web resources
• WRF model users site http://www.mmm.ucar.edu/wrf/users • ARW users’ guide http://www.mmm.ucar.edu/wrf/users/docs/user_guide/contents.
html • WRF-ARW/WPS online tutorial • http://www.mmm.ucar.edu/wrf/users/docs/user_guide_V3/conte nts.html
• WRF namelist description http://www.mmm.ucar.edu/wrf/users/docs/user_guide_V3/users _guide_chap5.htm#_Description_of_Namelist Tutorial presentations http://www.mmm.ucar.edu/wrf/users/supports/tutorial.html
My resources • This presentation (PPT format)
http://www.atmos.ucla.edu/~fovell/WRF/wrf_tutori al_2009.ppt
• WRF on Mac OS X
http://macwrf.blogspot.com
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
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 would need to do this every time, in every window]
# 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 4096000 setenv P4_SOCKBUFSIZE 65536 unlimit limit coredumpsize 0 This environment uses my versions of netcdf, mpich, grads, RIP
Set up a run directory
> cd > mkdir SQUALL > cd SQUALL > cp /home/fovell/WRFtutorial/make_all_links.csh .
> make_all_links.csh
> cp /home/fovell/WRFtutorial/namelist.* .
[copies namelist.input, namelist.wps]
WRF for real-data run A 2006 squall-line
[This example uses data that may not remain online]
Surface map 00Z April 3, 2006
Radar 00Z April 3, 2006
WPS overview
• Tasks – (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
• Input data source: FNL analysis
namelist.wps
&share wrf_core = 'ARW', max_dom = 3, start_date = '2006-04-02_18:00:00', '2006-04-02_18:00:00','2006-04-02_18:00:00', end_date = '2006-04-04_00:00:00', '2006-04-04_00:00:00','2006-04-04_00:00:00', interval_seconds = 21600 io_form_geogrid = 2, / • • Setup for 3 telescoping domains • For start_date , end_date need one column for each domain interval_seconds is parent model data frequency (here, 6 h f or FNL data)
namelist.wps (cont.)
&geogrid parent_id = 1, 1, 2, parent_grid_ratio = 1, 3, 3, i_parent_start = 1, 15, 30, j_parent_start = 1, 15, 37, e_we = 70, 133, 190, e_sn = 70, 133, 190, geog_data_res = '10m','2m','30s', dx = 36000, dy = 36000, map_proj = 'lambert', ref_lat = 39., ref_lon = -88.00, truelat1 = 30.0, truelat2 = 60.0, stand_lon = -88.00, geog_data_path = '/home/fovell/WPS_GEOG/geog' /
there is more…
geogrid - create domain
> geogrid.exe
* creates geo_em.d0*.nc (a NetCDF file) * look for “ Successful completion of geogrid .” > plotgrids.exe
* creates gmeta > idt gmeta * uses NCAR graphics tool to view domain
> ncdump geo_em.d01.nc | more
netcdf geo_em.d01 { dimensions: Time = UNLIMITED ; // (1 currently) DateStrLen = 19 ; west_east = 69 ; south_north = 69 ; south_north_stag west_east_stag = 70 ; = 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" ;
Parent model data issues • Sources include GFS, FNL, NAM, RUC, NARR and NNRP reanalysis data, etc.
• Need a different Vtable (variable table) for each source
– e.g., Vtable.GFS
, Vtable.NAM
, Vtable.NARR
, etc. – Look in /home/fovell/WRFtutorial
Accessing parent model data
> link_grib.csh /home/fovell/FNL2006/fnl * links to where parent model for case resides ** data files start with ‘fnl*’ > ln -sf /home/fovell/WRFtutorial/Vtable.GFS Vtable * specifies appropriate Vtable > ungrib.exe
* extracts parent model data * look for “ Successful completion of ungrib .”
Next step: metgrid
> metgrid.exe
...hopefully you see ...
“ Successful completion of metgrid .” ...Output looks like...
met_em.d01.2006-04-02_18:00:00.nc met_em.d02.2006-04-03_12:00:00.nc
met_em.d01.2006-04-03_00:00:00.nc met_em.d02.2006-04-03_18:00:00.nc
met_em.d01.2006-04-03_06:00:00.nc met_em.d02.2006-04-04_00:00:00.nc
met_em.d01.2006-04-03_12:00:00.nc met_em.d03.2006-04-02_18:00:00.nc
met_em.d01.2006-04-03_18:00:00.nc met_em.d03.2006-04-03_00:00:00.nc
met_em.d01.2006-04-04_00:00:00.nc met_em.d03.2006-04-03_06:00:00.nc
met_em.d02.2006-04-02_18:00:00.nc met_em.d03.2006-04-03_12:00:00.nc
met_em.d02.2006-04-03_00:00:00.nc met_em.d03.2006-04-03_18:00:00.nc
met_em.d02.2006-04-03_06:00:00.nc met_em.d03.2006-04-04_00:00:00.nc
ncdump on a metgrid file
netcdf met_em.d01.2006-04-02_18:00:00 { dimensions: Time = UNLIMITED ; // (1 currently) DateStrLen = 19 ; west_east = 69 ; south_north = 69 ; num_metgrid_levels = 27 ; This data source has 27 vertical levels.
This will vary with source - so check an met_em * file.
WRF model steps
• Tasks – 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 • Examples set up to use OpenMP on a single node (i.e., WRF will use 1 or more cores)
namelist.input
&time_control run_days = 0, run_hours = 12, run_minutes = 0, run_seconds = 0, start_year = 2006, 2006, 2006, start_month = 04, 04, 04, start_day = 02, 02, 02, start_hour = 18, 18, 18, start_minute = 00, 00, 00, start_second = 00, 00, 00, end_year = 2006, 2006, 2006, end_month = 04, 04, 04, end_day = 03, 03, 03, end_hour = 06, 06, 06, end_minute = 00, 00, 00, end_second = 00, 00, 00, For start_*, end_*, one column per domain
namelist.input
(cont.)
interval_seconds = 21600 input_from_file = .true.,.true.,.true., history_interval = 60, 60, 60, frames_per_outfile = 1, 1, 1, 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
namelist.input
(cont.)
&domains time_step = 60, time_step_fract_num = 0, time_step_fract_den = 1, max_dom = 1, s_we = 1, 1, 1, e_we = 70, 133, 190, s_sn = 1, 1, 1, e_sn = 70, 133, 190, s_vert = 1, 1, 1, e_vert = 51, 51, 51, num_metgrid_levels = 27 dx = 36000, 12000, 4000, dy = 36000, 12000, 4000, grid_id = 1, 2, 3, parent_id = 0, 1, 2, i_parent_start = 0, 15, 30, j_parent_start = 0, 15, 37, parent_grid_ratio = 1, 3, 3, parent_time_step_ratio = 1, 3, 3,
namelist.input
(cont.)
&physics mp_physics = 3, 3, 3, ra_lw_physics = 1, 1, 1, ra_sw_physics = 1, 1, 1, radt = 10, 10, 10, cam_abs_freq_s = 21600, cam_abs_dim1 = 4, cam_abs_dim2 = 51, levsiz = 59, paerlev = 29, sf_sfclay_physics = 1, 1, 1, sf_surface_physics = 2, 2, 2, bl_pbl_physics = 1, 1, 1, bldt = 0, 0, 0, cu_physics cudt = 1, 1, 0, = 5, 5, 5,
there is more…
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 ( bl ) scheme is called every time step • Standard practice: call bl every 5 min, ra every time step, (radiation) every 10 min cu
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., 5000., 5000., dampcoef = 0.01, 0.01, 0.01
khdif = 0, 0, 0, kvdif = 0, 0, 0, Only some diff_opt/km_opt combinations make sense, and choices are resolution-dependent.
More info: http://www.mmm.ucar.edu/wrf/users/supports/tutorial.html
http://www.mmm.ucar.edu/wrf/users/tutorial/200901/WRF_Physics_Dudhia.pdf
real.exe
• Has changed a lot since version 2.1.2
• Number of vertical model levels is specified in this step e_vert = 51, 51, 51, num_metgrid_levels = 27 • The num_metgrid_levels model; you set here e_vert comes from parent (number of WRF levels) – Can reset WRF levels by rerunning real.exe
– Can also specify which levels you want
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
,
Run real.exe and
> setenv | grep OMP
wrf.exe
OMP_NUM_THREADS=4 > real.exe
[look for…] d01 2006-04-03_06:00:00 real_em: SUCCESS COMPLETE REAL_EM INIT • max_dom in namelist.input
is set to 1… although we created three domains, only one will be used in the run
Run wrf.exe
• Output of real.exe is wrfbdy_d01 wrfinput_d01 (NetCDF files) and - Input files created for each domain, up to max_dom • Run the model > nohup time wrf.exe > wrf.out & • Creates wrfout_d0* files keyed by simulation date for each domain > tail -f wrf.out
[to watch the model run]
WRF model output
• Namelist set up to do 12 h run • Look for at end of wrf.out
file: d01 2006-04-03_06:00:00 wrf: SUCCESS COMPLETE WRF • Output files created: wrfout_d01_2006-04-02_18:00:00 wrfout_d01_2006-04-03_01:00:00 wrfout_d01_2006-04-02_19:00:00 wrfout_d01_2006-04-03_02:00:00 wrfout_d01_2006-04-02_20:00:00 wrfout_d01_2006-04-03_03:00:00 wrfout_d01_2006-04-02_21:00:00 wrfout_d01_2006-04-03_04:00:00 wrfout_d01_2006-04-02_22:00:00 wrfout_d01_2006-04-03_05:00:00 wrfout_d01_2006-04-02_23:00:00 wrfout_d01_2006-04-03_06:00:00 wrfout_d01_2006-04-03_00:00:00 • This is because history_interval min and frames_per_outfile was 1 was 60
Postprocessing WRF output: RIP and GrADS (Vis5D, ARWpost and VAPOR also exist)
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
RIP procedure
> cp /home/fovell/WRFtutorial/rip.T2.in .
> 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
Domain 1 terrain
12 h forecast
(2m T - color; 1h precip totals; 10 m vector winds)
12 h forecast
(2m T - color; 1h precip totals; 10 m vector winds)
RIP script
=========================================================================== feld=T2; ptyp=hc; vcor=s; levs=1fb; cint=1; cmth=fill;> arng; cbeg=273; cend=303; 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 =========================================================================== http://www.mmm.ucar.edu/wrf/users/docs/ripug.htm
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 difficult to construct
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
http://grads.iges.org/grads/head.html
control_file
-3 ! times to put in GrADS file, negative ignores this 0001-01-01_00:00:00 0001-01-01_00:05:00 0001-01-01_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
control_file (cont.)
! All list of files to read here [more…] ! Indent not to read ! Full path OK wrfout_d01_2006-04-02_18:00:00 wrfout_d01_2006-04-02_19:00:00 wrfout_d01_2006-04-02_20:00:00 end_of_file_list ! Now we check to see what to do with the data real ! real (input/output) / ideal / static 1 ! 0=no map background in grads, 1=map background in grads -1 ! 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
[more…]
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]
12 h forecast
(2 m T, 1 h precip totals, 10 m winds)
GrADS ctl file
dset ^run1g.dat
undef 1.e35
pdef 69 69 lcc 27.026 -100.234 1.000 1.000 60. 30. -88.000 36000. 36000.
xdef 228 linear -106.5 0.16216215
ydef 148 linear 26.0 0.16216215
zdef 50 levels 0.02976
0.09550
0.18799
[more…] tdef 13 linear 18:00z02apr2006 1hr vars 24 U 50 0 U Compoment of wind V 50 0 V Component of wind W 50 0 W Component of wind THETA 50 0 Theta TC 50 0 Temperature in C [more…]
Sometimes, wrf_to_grads fails to detect proper time increment. In this case, I manually changed “19hr” to “1hr”. A bug.
WRF for idealized cases
Idealized cases
• WRF comes with “pre-packaged” idealized case examples (2D squall line, 2D sea breeze, 3D supercell, mountain wave, etc.) • Type compile to see list of cases • 2D examples cannot use MPI or OpenMP • Can be modified – Next example: modified 3D supercell to do 3D squall line initialized with a line thermal w/ random perturbations
6 h forecast surface T’ and column max W
= end =