[gradsusr] WRF data in grads: Problem with the levels
Nick Heath
nkh09 at fsu.edu
Thu Sep 15 08:37:45 EDT 2011
Hey Catherine,
Unfortunately, to extract the height/pressure levels at the model sigma levels, and display WRF data in GrADS, there is an intermediate step. If you go here: http://www.mmm.ucar.edu/wrf/users/ and go to the Download tab, there is a Post-Processing program called ARWPost that converts WRF output into a GrADS friendly binary and even produces the control file for you. As you will see, the control file will look almost identical to the one you created, but will have the extracted pressure/height levels that you specify in the namelist. I have had problems with ARWPost creating really weird output, but I do not think there is any alternative right now if you want to use GrADS.
-Nick
----- Original Message -----
From: Catherine Meissner <catherine at windsim.com>
Date: Thursday, September 15, 2011 8:39 am
Subject: [gradsusr] WRF data in grads: Problem with the levels
To: gradsusr at gradsusr.org
> Hello,
>
>
>
> I am using WRF data files in GrADS version 2.0.a9oga, in windows.
>
> Having been unable to open the WRF files using xdfopen or sdfopen I
> havewritten my own CTL file in order to open the data. Everything
> is working for
> me except that the z levels which the file contains do not seem to
> correspond to the pressure. The nc dump suggests there are 29
> levels (which
> is correct as there were 29 eta levels in the WRF file).
>
> However the range of
>
> these levels is from 2986950,2887400,2787850 ... up to 199550,
> 100000. How
> can these numbers be related to pressure?
>
>
>
> All I need to know is what these Z levels mean and how I can wither
> convertthem to pressure or to height. Thanks for any help offered.
>
>
>
> The Corresponding CTL file is:
>
>
>
> dset ^wrfout_d02_%y4-%m2-%d2_%h2_%n2_00
>
> dtype netcdf
>
> title "Iberdrola data for Jan2008"
>
> undef -1e+30
>
> options template
>
> pdef 140 140 lcc 33.87970 -11.30862777011 1 1 43.427 43.427 -
> 3.839993 10000
> 10000 xdef 140 linear -4.5000000 0.004 ydef 140 linear 41.950000
> 0.0032 zdef
> 30 linear 2986950 2887400,
> 2787850,2688300,2588750,2489200,2389650,2290100,2190550,2091000,1991450,1891
> 800,1792300,1692800,1593250,1493700,1394150,1294600,1195050,1095500,995950,8
> 96400,
>
> 796850,697300,597750,498200,398650,299100,199550,100000
>
> tdef 480 linear 00:00Z01jan2008 1hr
>
>
>
> vars 4
>
> U=>u 29 t,z,y,x westerly wind
>
> V=>v 29 t,z,y,x southerly wind
>
> P=>p 29 t,z,y,x Pressure
>
> T=>t 29 t,z,y,x perturbation potential temperature
> (theta-t0)
>
> Endvars
>
>
>
> the ncdump is:
>
>
>
> netcdf wrfout_d02_2007-12-31_18_00_00 {
>
> dimensions:
>
> Time = UNLIMITED ; // (1 currently)
>
> DateStrLen = 19 ;
>
> west_east = 140 ;
>
> south_north = 140 ;
>
> bottom_top = 29 ;
>
> bottom_top_stag = 30 ;
>
> soil_layers_stag = 4 ;
>
> west_east_stag = 141 ;
>
> force_layers = 8 ;
>
> south_north_stag = 141 ;
>
> variables:
>
> char Times(Time, DateStrLen) ;
>
> float LU_INDEX(Time, south_north, west_east) ;
>
> LU_INDEX:FieldType = 104 ;
>
> LU_INDEX:MemoryOrder = "XY " ;
>
> LU_INDEX:description = "LAND USE CATEGORY" ;
>
> LU_INDEX:units = "" ;
>
> LU_INDEX:stagger = "" ;
>
> LU_INDEX:coordinates = "XLONG XLAT" ;
>
> float ZNU(Time, bottom_top) ;
>
> ZNU:FieldType = 104 ;
>
> ZNU:MemoryOrder = "Z " ;
>
> ZNU:description = "eta values on half (mass)
> levels" ;
>
> ZNU:units = "" ;
>
> ZNU:stagger = "" ;
>
> float ZNW(Time, bottom_top_stag) ;
>
> ZNW:FieldType = 104 ;
>
> ZNW:MemoryOrder = "Z " ;
>
> ZNW:description = "eta values on full (w) levels" ;
>
> ZNW:units = "" ;
>
> ZNW:stagger = "Z" ; (... and many more variables
> listed)
>
> // global attributes:
>
> :TITLE = " OUTPUT FROM WRF V3.1.1 MODEL" ;
>
> :START_DATE = "2007-12-31_18:00:00" ;
>
> :SIMULATION_START_DATE = "2007-12-31_18:00:00" ;
>
> :WEST-EAST_GRID_DIMENSION = 141 ;
>
> :SOUTH-NORTH_GRID_DIMENSION = 141 ;
>
> :BOTTOM-TOP_GRID_DIMENSION = 30 ;
>
> :DX = 10000.f ;
>
> :DY = 10000.f ;
>
> :GRIDTYPE = "C" ;
>
> :DIFF_OPT = 1 ;
>
> :KM_OPT = 4 ;
>
> :DAMP_OPT = 0 ;
>
> :DAMPCOEF = 0.2f ;
>
> :KHDIF = 0.f ;
>
> :KVDIF = 0.f ;
>
> :MP_PHYSICS = 6 ;
>
> :RA_LW_PHYSICS = 1 ;
>
> :RA_SW_PHYSICS = 1 ;
>
> :SF_SFCLAY_PHYSICS = 2 ;
>
> :SF_SURFACE_PHYSICS = 2 ;
>
> :BL_PBL_PHYSICS = 2 ;
>
> :CU_PHYSICS = 0 ;
>
> :SURFACE_INPUT_SOURCE = 1 ;
>
> :SST_UPDATE = 0 ;
>
> :GRID_FDDA = 0 ;
>
> :GFDDA_INTERVAL_M = 0 ;
>
> :GFDDA_END_H = 0 ;
>
> :GRID_SFDDA = 0 ;
>
> :SGFDDA_INTERVAL_M = 0 ;
>
> :SGFDDA_END_H = 0 ;
>
> :SF_URBAN_PHYSICS = 0 ;
>
> :FEEDBACK = 1 ;
>
> :SMOOTH_OPTION = 0 ;
>
> :SWRAD_SCAT = 1.f ;
>
> :W_DAMPING = 0 ;
>
> :MOIST_ADV_OPT = 1 ;
>
> :SCALAR_ADV_OPT = 1 ;
>
> :TKE_ADV_OPT = 1 ;
>
> :DIFF_6TH_OPT = 0 ;
>
> :DIFF_6TH_FACTOR = 0.12f ;
>
> :OBS_NUDGE_OPT = 0 ;
>
> :WEST-EAST_PATCH_START_UNSTAG = 1 ;
>
> :WEST-EAST_PATCH_END_UNSTAG = 140 ;
>
> :WEST-EAST_PATCH_START_STAG = 1 ;
>
> :WEST-EAST_PATCH_END_STAG = 141 ;
>
> :SOUTH-NORTH_PATCH_START_UNSTAG = 1 ;
>
> :SOUTH-NORTH_PATCH_END_UNSTAG = 140 ;
>
> :SOUTH-NORTH_PATCH_START_STAG = 1 ;
>
> :SOUTH-NORTH_PATCH_END_STAG = 141 ;
>
> :BOTTOM-TOP_PATCH_START_UNSTAG = 1 ;
>
> :BOTTOM-TOP_PATCH_END_UNSTAG = 29 ;
>
> :BOTTOM-TOP_PATCH_START_STAG = 1 ;
>
> :BOTTOM-TOP_PATCH_END_STAG = 30 ;
>
> :GRID_ID = 2 ;
>
> :PARENT_ID = 1 ;
>
> :I_PARENT_START = 14 ;
>
> :J_PARENT_START = 10 ;
>
> :PARENT_GRID_RATIO = 5 ;
>
> :DT = 60.f ;
>
> :CEN_LAT = 40.5046f ;
>
> :CEN_LON = -3.839993f ;
>
> :TRUELAT1 = 43.427f ;
>
> :TRUELAT2 = 43.427f ;
>
> :MOAD_CEN_LAT = 43.427f ;
>
> :STAND_LON = -3.84f ;
>
> :POLE_LAT = 90.f ;
>
> :POLE_LON = 0.f ;
>
> :GMT = 18.f ;
>
> :JULYR = 2007 ;
>
> :JULDAY = 365 ;
>
> :MAP_PROJ = 1 ;
>
> :MMINLU = "" ;
>
> :NUM_LAND_CAT = 24 ;
>
> :ISWATER = 16 ;
>
> :ISLAKE = 0 ;
>
> :ISICE = 0 ;
>
> :ISURBAN = 0 ;
>
> :ISOILWATER = 0 ;
>
> }
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> Catherine Meissner
> Software Development Manager
>
>
> Fjordgaten 15
> N-3125 Tønsberg, Norway
>
> Switchboard +47 33 38 18 00
>
> <http://www.windsim.com/> www.windsim.com
>
> Email
>
> Direct
>
> Fax
>
>
>
> <mailto:kristine at windsim.com> catherine at windsim.com
>
> +47 33 38 18 06
> +47 33 38 18 08
>
> Upcoming WindSim events:
>
>
>
> Brazil WindPower 2011
>
> August 31 – 2, Rio de Janeiro, Brazil
> Booth 141
>
> VIND 2011
>
> September 14 – 15, Stockholm, Sweden
>
>
>
> EOLICA EXPO 2011
>
> September 14 – 16, Rome, Italy
> Booth B8/C7
>
>
>
> GREEN EXPO 2011
>
> September 27 – 29, Mexico City, Mexico
>
>
>
> WIND POWER EXPO+
>
> September 27 – 29, Zaragoza, Spain
>
> CanWEA
>
> October 3 – 6, Vancouver, Canada
>
>
>
> For upcoming WindSim training courses, please visit:
> <http://www.windsim.com/events/training-courses.aspx>
> http://www.windsim.com/events/training-courses.aspx
>
>
>
> This message contains information that may be privileged or
> confidential and is the property of WindSim AS. It is
> intendedonly for the person to whom it is addressed. If
> you are not the
> intended recipient, you are not authorized to print, retain,
> copy,
> disseminate, distribute, or use this message or any part
> thereof.If you receive this message in error, please notify
> the sender
> immediately and delete all copies of this message.
>
>
>
>
>
>
>
>
More information about the gradsusr
mailing list