User’s Guide for Advanced Research WRF (ARW) Modeling System Version 2

 

Chapter 8: Post-Processing Utilities

Table of Contents

·        Introduction

·        NCL

·        RIP4

·        ARWpost

·        WPP

·        read_wrf_nc utility

·        iowrf utility

·        Tools

Introduction

 

There are a number of visualization tools available to display WRF-ARW (http://wrf-model.org/) model data.  Model data in netCDF format, can essentially be displayed using any tool capable of displaying this data format.

 

Currently the following post-processing utilities are supported, NCL, RIP4, ARWpost (converter to GrADS and Vis5D), and WPP.

 

NCL and RIP4 can currently only read data in netCDF format, while ARWpost can read data in netCDF and GRIB1 format, and WPP can read data in netCDF and binary format.

 

Required software:

The only library that is always required is the netCDF package from Unidata (http://www.unidata.ucar.edu/ :  login > Downloads > NetCDF - registration login required).

 

netCDF stands for Network Common Data Form. This format is platform independent, i.e., data files can be read on both big_endian and little_endian computers, regardless of where the file was created. To use the netCDF libraries, ensure that the paths to these libraries are set correct in your login scripts as well as all Makefiles.

 

Additional libraries required by each of the supported post-processing packages:

-         NCL (http://www.ncl.ucar.edu/)

-         GrADS (http://grads.iges.org/home.html)

-         Vis5D (http://www.ssec.wisc.edu/~billh/vis5d.html)

-         GEMPAK (http://my.unidata.ucar.edu/content/software/gempak/index.html)


NCL

 

With the use of NCL Libraries (http://www.ncl.ucar.edu), WRF-ARW data can easily be displayed.

 

The information on these pages has been put together to help users generate NCL scripts to display their WRF-ARW model data.

 

Some example scripts are provided, but in order to fully utilize the functionality of the NCL Libraries, users should adapt these for their own needs, or write their own scripts.

 

NCL can process WRF ARW static/input and output files, as well as WRF-Var output data. Both single and double precision data can be processed.

 

What is NEW?

 

Up to July 2007, one needed to install the NCL Libraries (http://www.ncl.ucar.edu), AND the WRF_NCL package. (details’ regarding the old WRF_NCL package is available in Appendix B of this User’s Guide).

 

In July 2007, the WRF_NCL package has been incorporated into the NCL Libraries, thus only the NCL Libraries, are now needed. NCL version 4.3.1 or higher is required. (NOTE: some of the built-in functions have been available since NCL version 4.3.0, but the complete WRF-ARW  package is only available since version 4.3.1).

 

What has changed?

 

-         The basic functions / procedures used in WRF_NCL has been moved in under the NCL libraries and are now located in "$NCARG_ROOT/lib/ncarg/nclscripts/wrf/".

 

-         All the FORTRAN subroutines used for diagnostics and interpolation (previously located in wrf_user_fortran_util_0.f) has been re-coded into NCL in-line functions. This means a user no longer need to compile these.

 

What is NCL

 

The NCAR Command Language (NCL) is a free interpreted language designed specifically for scientific data processing and visualization. NCL has robust file input and output. It can read in netCDF, HDF4, HDF4-EOS, GRIB, binary and ASCII data. The graphics are world class and highly customizable.

 

It runs on many different operating systems including Solaris, AIX, IRIX, Linux, MacOSX, Dec Alpha, and Cygwin/X running on Windows. The NCL binaries are freely available at: http://www.ncl.ucar.edu/Download/

 

To read more about NCL, please visit: http://www.ncl.ucar.edu/overview.shtml

 

Necessary software

NCL libraries (version 4.3.1 or higher). 

 

.hlureasfile

Create a file called .hluresfile in your $HOME directory. This file controls the color / background / fonts and basic size of your plot. For more information regarding this file, see: http://www.ncl.ucar.edu/Document/Graphics/hlures.shtml.

  

NOTE: This file must reside in your $HOME directory and not where you plan on running NCL.

 

Below is the .hluresfile used in the example scripts posted on the web (scripts are available at, http://www2.mmm.ucar.edu/wrf/users/graphics/NCL/NCL.htm).  If a different color table is used, the plots will appear different. Copy the following to your ~/.hluresfile. (A copy of this file is available at, http://www2.mmm.ucar.edu/wrf/users/graphics/NCL/.hluresfile)

 

*wkColorMap : WhViBlGrYeOrReWh

*wkBackgroundColor : white

*wkForegroundColor : black

*FuncCode : ~

*TextFuncCode : ~

*Font : helvetica

*wkWidth : 900

*wkHeight : 900

 

NOTE: If your image has a black background with white lettering, your .hluresfile has not been created correctly, or it is in the wrong location.

 

 

Create NCL scripts

The basic outline of any NCL script will look as follows:

load external functions and procedures

 

begin

 

; Open input file(s)

; Open graphical output

 

; Read variables

 

; Set up plot resources & Create plots

; Output graphics

 

end

 

 

For example, let’s create a script to plot Temperature and Wind as shown in the picture below.

 

 

 

 

 

; load functions and procedures

load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"

load "$NCARG_ROOT/lib/ncarg/nclscripts/wrf/WRFUserARW.ncl"

 

begin

 

; WRF ARW input file

a = addfile("../wrfout_d01_2000-01-24_12:00:00.nc","r")

 

; Output on screen. Output will be called "plt_Surface1"

type = "x11"

wks = gsn_open_wks(type,"plt_Surface1")

 

; Set basic options

; Give our plot a main title ; Set Footers off

ARWres = True

ARWres@MainTitle = "REAL-TIME WRF"

ARWres@Footer = False

 

;---------------------------------------------------------------

; Lets find out how many times are in the datasets.

times = wrf_user_list_times(a) ; get times in the file

ntimes = dimsizes(times) ; number of times in the file

it = ntimes-1 ; we are only interested in the last time

ARWres@TimeLabel = times(it) ; keep some time information

 

; Create a MAP background

mpres = True

map = wrf_map(wks,a,mpres)

 

;---------------------------------------------------------------

; Get variables

 

tc2 = wrf_user_getvar(a,"T2",it) ; Get T2 (deg K)

   tc2 = tc2-273.16 ; Convert to deg C

   tf2 = 1.8*tc2+32. ; Turn temperature into Fahrenheit

   tf2@description = "Surface Temperature"

   tf2@units = "F" td_f = 1.8*td2+32.

 

u10 = wrf_user_getvar(a,"U10",it) ; Get U10

v10 = wrf_user_getvar(a,"V10",it) ; get V10

   u10 = u10*1.94386 ; Turn wind into knots

   v10 = v10*1.94386

   u10@units = "kts"

   v10@units = "kts"

 

;---------------------------------------------------------------




; Plotting options for T

opts = ARWres

opts@cnFillOn = True ; Shaded plot

opts@ContourParameters = (/ -20., 90., 5./) ; Contour intervals

opts@gsnSpreadColorEnd = -3 ; End 3rd from last color

contour_tc = wrf_contour(a,wks,tf2,opts) ; Create plot

delete(opts)

 

 

; Plotting options for Wind Vectors

opts = ARWres

opts@FieldTitle = "Winds" ; Overwrite the field title

opts@NumVectors = 47 ; Density of wind barbs - high is denser

vector = wrf_vector(a,wks,u10,v10,opts); Create plot

delete(opts)

 

 

; MAKE PLOTS 

wrf_map_overlay(wks,map,(/contour_tc,contour_psl,vector/),True)

 

;---------------------------------------------------------------

 

 

end

 

 

Extra sample scripts are available at, http://www2.mmm.ucar.edu/wrf/users/graphics/NCL/NCL.htm

 

Run NCL scripts

    

ncl    NCL_script

 

The output created with this command is controlled by the line:
wks = gsn_open_wk (type,"Output")     inside the NCL script
where type can be x11, pdf, ncgm, ps, eps

 

Miscellaneous

 

For high quality images, create pdf / ps or eps images directly via the ncl scripts (type = pdf / ps / eps)

 

 

See the Tools section at the end of this chapter for more information concerning other types of graphical formats and conversions between graphical formats.

Functions / Procedures under "$NCARG_ROOT/lib/ncarg/nclscripts/wrf/"

 

WRFUserARW.ncl

 

These functions and procedures are described fully on the NCL web site (http://www.ncl.ucar.edu/Document/Functions/WRF_arw).

-         Controls plotting options. If you want to change the defaults, change them in your script.
e.g., if you do not want footers at the bottom of your plots, set "res@Footer=False".

 

MainTitlePos

Options are top "Left", "Center", "Right"

InitTime

Add Initial Time to plot

ValidTime

Add Valid Time to Plot

TimePos

Placement of Time Information. Options are top "Left" or "Right". If MainTitlePos and TimePos are on same side, Time Information will be plotted under the Main Title

Footer

Add some model information as a Footer to the plots

 

-         Controls map plotting, creation of plots and overlays, via the following functions:

 

wrf_contour

wrf_vector    
wrf_map
wrf_map_zoom
wrf_map_overlay
wrf_overlay

-         Get variables from wrf files (wrf_user_getvar)

 

-         Calculate diagnostics


All diagnostics are in-line functions within NCL (http://www.ncl.ucar.edu/Document/Functions/wrf.shtml) .
 These functions can be used directly inside any NCL script without the use of the WRFUserARW.ncl script, but it is recommended to use the interface script, as this will make the use of these functions much easier.

-         Interpolate data horizontally and vertically  (wrf_user_intrp3d)

-         Obtain x/y locations for given lat/long locations  (wrf_user_latlon_to_ij)

-         Extract times from wrf files  (wrf_user_list_times)

Adding diagnostics using FORTRAN code

 

It is possible to link your favorite FORTRAN diagnostics routines to NCL. The only requirement is that the code must be written in FORTRAN 77. NCL does not recognize FORTRAN 90 code.

 

Let’s use a routine that calculated temperature (K) from theta and pressure. Add the markers NCLFORTSTART and NCLEND to the subroutine as indicated below. Note, that local variables are outside these block markers.

 

      

C NCLFORTSTART

       subroutine compute_tk (tk,pressure,theta, nx, ny, nz)
       implicit none

 

C  Variables

       integer nx,ny,nz
       real    pi,

       real    tk(nx,ny,nz)
       real    pressure(nx,ny,nz), theta(nx,ny,nz)

C NCLEND

 

C  Local Variables

       integer i,j,k

       DO k=1,nz
          DO j=1,ny        
          DO i=1,nx                     
              pi=(pressure(i,j,k) 100000.)**(287./1004.)
              tk(i,j,k) = pi*theta(i,j,k)
          ENDDO
          ENDDO

       ENDDO

  end

 

 

Now compile this code using the NCL script WRAPIT.

 

WRAPIT myTK.f

 

If WRAPIT cannot be found, make sure the environment variable NCARG_ROOT has been set correctly.

 

If the subroutine compiles successfully, a new library will be created, called myTK.so. This library can be linked to an NCL script to calculate TK. See how this is done in the example below:

 

load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"

load "$NCARG_ROOT/lib/ncarg/nclscripts/wrf/WRFUserARW.ncl”
external myTK "./myTK.so"           

 

begin

 

            t = wrf_user_getvar(a,”T”,5)
            t = t + 300

            p = wrf_user_getvar(a,”pressure”,5)

 

            dim = dimsizes(t)

            tk = new( (/ dim(0), dim(1), dim(2) /), float)

 

            myTK :: compute_tk (tk,p,t,dim(2),dim(1),dim(0))

 

end

 
RIP4

RIP4 was adapted from the RIP code, originally developed to display MM5 model data. (Developed primarily by Mark Stoelinga, from both NCAR and the University of Washington)

 

The RIP users' guide (http://www2.mmm.ucar.edu/wrf/users/docs/ripug.htm) is essential reading.

 

 Code history

 

Version 4.0: reads WRF-ARW real output files

Version 4.1: reads idealized WRF-ARW datasets
Version 4.2: reads all the files produced by WPS
Version 4.3: reads files produced by WRF-NMM model (This document will only concentrate on running RIP4 for WRF-ARW. For details on running RIP4 for WRF-NMM, see the WRF-NMM User’s Guide: http://www.dtcenter.org/wrf-nmm/users/docs/user_guide/WPS/index.php)

 

 Necessary software

Obtain the RIP4 TAR file from the WRF Download page (http://www2.mmm.ucar.edu/wrf/users/download/get_source.html)

 

RIP4 only requires low level NCAR Graphics libraries. These libraries has been merged with the NCL libraries since the release of NCL version 5 (http://www.ncl.ucar.edu/), so if you don’t already have NCAR Graphics installed on your computer, install NCL.

 

Hardware

 

The code has been ported to: DEC Alpha, Linux (pgi and intel compilers). MAC (xlf and absoft compilers), SUN, SGI, IBM, CRAY and  Fujitsu computers.

 

Steps to compile and run

 

Unzip and untar RIP4.TAR.gz file

Inside the TAR file you will see the following files:

CHANGES
Doc/

Makefile

README

color.tbl

psadilookup.dat

sample_infiles/            | sample scripts moved under this directory in version 4.3

src/

stationlist

 

Compile the code

Typing "make" will produce the following list of compile options

 

make dec

make linux 

make intel
make mac_xlf        
make mac  

make sun

make sun2

make sun90

make sgi

make sgi64

make ibm

make cray

make vpp300

make vpp5000

make clean

make clobber

To Run on DEC_ALPHA

To Run on LINUX with PGI compiler 

To Run on LINUX with INTEL compiler

To Run on MAC_OS_X with Xlf Compiler                        To Run on MAC_OS_X with Absoft Compiler

To Run on SUN

To Run on SUN if make sun didn't work

To Run on SUN usingF90

To Run on SGI

To Run on 64-bit SGI

To Run on IBM SP2

To Run on NCAR's Cray

To Run on Fujitsu VPP 300

To Run on Fujitsu VPP 5000

to remove object files

to remove object files and executables

             

Pick the compiler option for the machine you are working on and type:
"make machine"

 

e.g.    make linux  
will compile the code for a Linux computer running PGI compiler

 

 After a successful compilation, the following new files should be created.

rip

RIP post-processing program.
Before using this program, first convert the input data to the correct format expected by this program, using the program ripdp

ripcomp

This program reads in two rip data files and compares their contents.

ripdp_mm5

RIP Data Preparation program for MM5 data 

ripdp_wrfarw
ripdp_wrfnmm

RIP Data Preparation program for WRF data

ripinterp

This program reads in model output (in rip-format files) from a coarse domain and from a fine domain, and creates a new file which has the data from the coarse domain file interpolated (bi-linearly) to the fine domain.  The header and data dimensions of the new file will be that of the fine domain, and the case name used in the file name will be the same as that of the fine domain file that was read in.

ripshow

This program reads in a rip data file and prints out the contents of the header record. 

showtraj

Sometimes, you may want to examine the contents of a trajectory position file. Since it is a binary file, the trajectory position file cannot simply be printed out. showtraj, reads the trajectory position file and prints out its contents in a readable form.  When you run showtraj, it prompts you for the name of the trajectory position file to be printed out. 

tabdiag

If fields are specified in the plot specification table for a trajectory calculation run, then RIP produces a .diag file that contains values of those fields along the trajectories. This file is an unformatted Fortran file; so another program is required to view the diagnostics. tabdiag serves this purpose. 

upscale

This program reads in model output (in rip-format files) from a coarse domain and from a fine domain, and replaces the coarse data with fine data at overlapping points. Any refinement ratio is allowed, and the fine domain borders do not have to coincide with coarse domain grid points.

 

 

Prepare the data

To prepare the data for the RIP program, one much first run RIPDP (RIP Data Preparation), for WRF (i.e., either ripdp_wrfarw or ripdp_wrfnmm depending on the core used when running the WRF model).

As this step will create a large number of extra files, creating a new directory to place these files in, will enable you to manage the files easier

 

            mkdir RIPDP

Edit the namelist    sample_infiles /ripdp_wrfarw_sample.in  (the use of this namelist is optional). The most important information needed in the namelist, is the times you want to process.

 

 

 

 

Run ripdp for WRF-ARW

 

ripdp_wrfarw   [-n namelist_file]   casename   [basic|all]   input1 input2 …

e.g.    ripdp_wrfarw   RIPDP/arw   all  
                ../wrfout_d01_2000-01-24_12:00:00 >& ripdp_log

 

            Check the ripdp_log for run time errors.

Edit the User Input File

The first step in creating the graphics you are interested in, is to edit the User Input File (UIP)  sample_infiles /rip_sample.in  (or create your own UIP)

The UIP file consists of:

-         2 namelists: userin (which control the general input specifications) and trajcalc (which control the creation of trajectories); and

-         the Plot Specification Table (PST), used to control the generation of the graphics

namelist: userin

Variable

Type

Description

idotitle

Integer

Control first part of title line.

titlecolor

Character

Control color of the title lines

ptimes

Integer

Times to process.
This can be a string of times or a series in the form of A,-B,C, which means "times from hour A, to hour B, every C hours"

ptimeunits

Character

Time units.
This can be either `h' (hours), `m' (minutes), or `s' (seconds)

tacc

Real

Time tolerance in seconds.
 Any time in the model output that is within tacc seconds of the time specified in ptimes will be processed.

timezone

Integer

Specifies the offset from Greenwich time.

iusdaylightrule

Integer

Flag to determine if US daylight saving is applied.

iinittime

Integer

Controls the plotting of the initial time on the plots.

ivalidtime

Integer

Controls the plotting of the plot valid time.

inearesth

Integer

Plot time as two digits rather than 4 digits.

flmin

Real

Left frame limit

flmax

Real

Right frame limit

fbmin

Real

Bottom frame limit

ftmax

Real

Top frame limit

ntextq

Integer

Quality of the text

ntextcd

Integer

Text font

fcoffset

Integer

Change initial time to something other than output initial time.

idotser

Integer

Generate time series output files (no plots) only ASCII file that can be used as input to a plotting program).

idescriptive

Integer

Use more descriptive plot titles.

icgmsplit

Integer

Split metacode into several files.

maxfld

Integer

Reserve memory for RIP.

ittrajcalc

Integer

Generate trajectory output files (use namelist trajcalc when this is set).

imakev5d

Integer

Generate output for Vis5D

 


Plot Specification Table

The second part of the RIP UIF consists of the Plot Specification Table. The PST provides all of the user control over particular aspects of individual frames and overlays.

 

The basic structure of the PST is as follows:

-         The first line of the PST is a line of consecutive equal signs. This line as well as the next two lines is ignored by RIP, it is simply a banner that says this is the start of the PST section.

-         After that there are several groups of one or more lines separated by a full line of equal signs. Each group of lines is a frame specification group (FSG), and it describes what will be plotted in a single frame of metacode. Each FSG must end with a full line of equal signs, so that RIP can determine where individual frames starts and ends.

-         Each line within a FGS is referred to as a plot specification line (PSL). A FSG that consists of three PSL lines will result in a single metacode frame with three overlaid plots.

Example of a frame specification groups (FSG's):

   ==============================================

   feld=tmc; ptyp=hc; vcor=p; levs=850; >

         cint=2; cmth=fill; cosq=-32,light.violet,-24,
         violet,-16,blue,-8,green,0,yellow,8,red,>   

         16,orange,24,brown,32,light.gray

   feld=ght; ptyp=hc; cint=30; linw=2

   feld=uuu,vvv; ptyp=hv; vcmx=-1; colr=white; intv=5

   feld=map; ptyp=hb

   feld=tic; ptyp=hb

 ===============================================

 

This FSG will generate 5 frames to create a single plot (as shown below):

-         Temperature in degrees C (feld=tmc). This will be plotted as a horizontal contour plot (ptyp=hc), on pressure levels (vcor=p). The data will be interpolated to 850 hPa. The contour intervals are set to 2 (cint=2), and shaded plots (cmth=fill) will be generated with a color range from light violet to light gray.

-         Geopotential heights (feld=ght) will also be plotted as a horizontal contour plot. This time the contour intervals will be 30 (cint=30), and contour lines, with a line width of 2 (linw=2) will be used.

-         Wind vectors (feld=uuu,vvv), plotted as barbs (vcmax=-1).

-         A map background will be displayed (feld=map), and

-         Tic marks will be placed on the plot (feld=tic).

 

 

 

 

 

Create graphics

First set the environment variables:
            setenv   NCARG_ROOT   your_ncarg_location   [typically /usr/local/ncarg]
            setenv   RIP_ROOT   your_rip4_directory

 

 

 

Run rip

      rip   [-f] model_case_name   rip_case_name
      e.g.    rip   -f    RIPDP/arw     rip_sample

 

If this is successful, the following files will be created
            rip_sample.cgm            gmeta file         
            rip_sample.out              log file - view this file if a problem occurred

 

View the meta file

To view the meta file, use the command "idt", e.g.


              idt rip_sample.cgm

 

Examples of plots created for both idealized and real cases are available from:
http://www2.mmm.ucar.edu/wrf/users/graphics/RIP4/RIP4.htm 

 

Miscellaneous

See the Tools section at the end of this chapter for more information concerning other types of graphical formats and conversions between graphical formats.

ARWpost

 

The ARWpost package reads in WRF-ARW model data and creates output in either GrADS or Vis5D format. 

 

The converter can read in WPS geogrid and metgrid data, and WRF-ARW input and output files.

 

The package makes use of the WRF IO API. The netCDF format has been tested extensively. GRIB1 format has been tested, but not as extensively. BINARY data cannot be read at the moment.

 

Necessary software

Obtain the ARWpost TAR file from the WRF Download page (http://www2.mmm.ucar.edu/wrf/users/download/get_source.html)

WRFV2 must be installed and available somewhere, as ARWpost makes use of the common IO API libraries from WRFV2.

GrADS software - You can download and install GrADS from   http://grads/iges.org/grads. The GrADS software is not needed to compile and run ARWpost.

Vis5D software (http://www.ssec.wisc.edu/~billh/vis5d.html)

Vis5D libraries must be installed to compile and run the ARWpost code, when creating Vis5D input data. If Vis5D files are not being created, these libraries are NOT needed to compile and run ARWpost.

 

Hardware

The code has been ported to the following machines

DEC Alpha , Linux (PGI and INTEL compilers) , MAC (with xlf compilers), SUN, SGI, IBM

 

Steps to compile and run

 

Untar ARWpost TAR file

Inside the TAR file you will have the following files:

README

 

arch/

clean*

compile*

configure*

Configure and compilation control

namelist.ARWpost

namelist

fields.plt

myLIST

Samples to illustrate how to add fields to plot via a file

src/

Source code

scripts/

Sample scripts

gribinfo.txt

gribmap.txt

Files needed to process GRIB1 data. Do not edit these files

util/

Utility program

 

Configure

WRFV2 must be compiled and available on your system.

 

           Type:    ./configure

 

You will see a list of options for your computer (below is an example for a Linux machine)

Will use NETCDF in dir: /usr/local/netcdf-pgi
-----------------------------------------------------------
Please select from among the following supported platforms.
1. PC Linux i486 i586 i686, PGI compiler (no vis5d)
2. PC Linux i486 i586 i686, PGI compiler (vis5d)
3. PC Linux i486 i586 i686, Intel compiler (no vis5d)
4. PC Linux i486 i586 i686, Intel compiler (vis5d)

Enter selection [1-4]

Make sure the netCDF path is correct.

Pick compile options for your machine (if you do not have Vis5D, or if you do not plan on using it, pick an option without Vis5D libraries)

 

Compile

If your WRFV2 code is NOT compiled under ../WRFV2, edit configure.arwp, and set "WRF_DIR" to the correct location of your WRFV2 code.

 

          Type:   ./compile

 

This will create the ARWpost.exe executable.

 

Edit the namelist.ARWpost file

 

Set times to process (&datetime)

 

Set input and output file names and fields to process (&io)


io_form_input

 

2=netCDF, 5=GRIB1

input_root_name

Path and root name of files to use as input. All files starting with the root name will be processed. Do not use wild characters in the input_root_name.

 

output_root_name

Output root name. When converting data to GrADS, output_root_name.ctl and output_root_name.dat will be created. For Vis5D, output_root_name.v5d will be created.

 

plot

Which fields to process.

Options are: all, basic, list, file, basic_file, basic_list, list_file, all_file, all_list, basic_list_file, all_list_file

Order has no effect, i.e., “all_list” and “list_all” are similar.
 
If "list" is used, a list of variables must be supplied under "fields"

If "file" is used, a list of variables must be added to a file, and the filename supplied under "fields_file”

 

fields

Fields to plot. Only used is list was used in the “plot” variable.

 

fields_file

File name that contains list of fields to plot.  Only used is file was used in the “plot” variable.

 

output_type

Options are 'grads' (default) or 'v5d'

 

mercator_defs

Set to true if mercator plots are distorted

 

 

Available diagnostics: height (model height in km), theta (potential temperature), tc (temperature in degrees C), tk (temperature in degrees K), td (dew point temperature in degrees C), rh (relative humidity), pressure (full model pressure in hPa), dbz (3d reflectivity), max_dbz (maximum reflectivity), slp (sea level pressure), mcape (maximum CAPE), mcin (maximum CIN), lcl (lifting condensation level), lfc (level of free convection), cape (3d CAPE), cin (3d CIN), umet and vmet (winds rotated to earth coordinates), u10m and v10m (10m winds rotated to earth coordinates), wdir (wind direction), wspd (wind speed)

 

Set levels to interpolate too (&interp)

interp_method: 0=sigma levels, -1=code defined "nice" height levels, 1=user defined height or pressure levels
interp_levels: Only used if interp_method=1
       Supply levels to interpolate to, in hPa (pressure) or km (height)
       Supply levels bottom to top

 

For  extra information regarding the namelist.ARWpost file, refer to the README file.


Run 

         Type:   ./ARWpost.exe

 

This will create output_root_name.dat and output_root_name.ctl files if creating GrADS input, and output_root_name.v5d, if creating Vis5D input.

 

NOW YOU ARE READY TO VIEW THE OUTPUT


GrADS

 

For general information about working with GrADS, view the GrADS home page:  http://grads.iges.org/grads/

 

To help users get started a number of GrADS scripts have been provided:

-         The scripts are all available in the scripts/ directory.

-         The scripts provided are only examples of the type of plots one can generate with GrADS data.

-         The user will need to modify these script to suit their data (e.g., if you  did not specify 0.25 km and 2 km as levels to interpolate to when you run the "bwave" data through the converter, the "bwave.gs" script will not display any plots, since it will specifically look for these to levels).

-         Scripts must be copied to the location of the input data.

  

GENERAL SCRIPTS

 

cbar.gs

Plot color bar on shaded plots (from GrADS home page)

rgbset.gs

Some extra colors (Users can add/change colors from color number 20 to 99)

skew.gs

Program to plot a skewT
TO RUN TYPE: run skew.gs (needs pressure level TC,TD,U,V as input)
User will be prompted if a hardcopy of the plot must be create - 1 for yes and 0 for no.
If 1 is entered, a GIF image will be created.
Need to enter lon/lat of point you are interested in
Need to enter time you are interested in
Can overlay 2 different times

plotALL.gs

Once you have opened a GrADS window, all one needs to do is run this script.

It will automatically find all .ctl files in the current directory and list them so one can pick which file to open.

Then the script will loop through all available fields and plot the ones a user requests.

 

-          

SCRIPTS FOR REAL DATA

 

 

real_surf.gs

Plot some surface data
Need input data on model levels

plevels.gs

Plot some pressure level fields
Need model output on pressure levels

rain.gs

Plot total rainfall
Need a model output data set (any vertical coordinate), that contain fields "RAINC" and "RAINNC"

cross_z.gs

Need z level data as input
Will plot a NS and EW cross section of RH and T (C)
Plots will run through middle of the domain

zlevels.gs

Plot some height level fields
Need input data on height levels
Will plot data on 2, 5, 10 and 16km levels

input.gs

Need WRF INPUT data on height levels

 

-          

SCRIPTS FOR IDEALIZED DATA

 

 

bwave.gs

Need height level data as input
Will look for 0.25 and 2 km data to plot

grav2d.gs

Need normal model level data

hill2d.gs

Need normal model level data

qss.gs

Need height level data as input.
Will look for heights 0.75, 1.5, 4 and 8 km to plot

sqx.gs

Need normal model level data a input

sqy.gs

Need normal model level data a input

 

Examples of plots created for both idealized and real cases are available from:
http://www2.mmm.ucar.edu/wrf/users/graphics/ARWpost/ARWpost.htm 

 

Trouble Shooting

The code executes correctly, but you get "NaN" or "Undefined Grid" for all fields
when displaying the data.

 

Look in the .ctl file.

a) If the second line is:

options byteswapped

Remove this line from your .ctl file and try to display the data again.
If this SOLVES the problem, you need to remove the -Dbytesw option from configure.arwp

b) If the line below does NOT appear in your .ctl file:

options byteswapped

ADD this line as the second line in the .ctl file.
Try to display the data again.
If this SOLVES the problem, you need to ADD the -Dbytesw option for configure.arwp

The line "options byteswapped" is often needed on some computers (DEC alpha as an example). It is also often needed if you run the converter on one computer and use another to display the data.  

 

Vis5D

 

For general information about working with Vis5D, view the Vis5D home page:  http://www.ssec.wisc.edu/~billh/vis5d.html

 

 

 

WPP

 

The NCEP WRF Postprocessor was designed to interpolate both WRF-ARW and WRF-NMM output from their native grids to National Weather Service (NWS) standard levels (pressure, height, etc.) and standard output grids (AWIPS, Lambert Conformal, polar-stereographic, etc.) in NWS and World Meteorological Organization (WMO) GRIB1 format. This package also provides an option to output fields on the model’s native vertical levels.

 

The adaptation of the original WRF Postprocessor package and User’s Guide (by Mike Baldwin of NSSL/CIMMS and Hui-Ya Chuang of NCEP/EMC) was done by Lígia Bernardet (NOAA/FSL/DTC) in collaboration with Dusan Jovic (NCEP/EMC), Robert Rozumalski (COMET), Wesley Ebisuzaki (NWS/HQTR), and Louisa Nance (NCAR/DTC). The upgrade to WRF Postprocessor Version 2.2 was performed by Hui-Ya Chuang and Dusan Jovic (NCEP/EMC).

 

This document will mainly deal with running the WPP package for the WRF-ARW modeling system. For details on running the package for the WRF-NMM system, please refer to the WRF-NMM User’s Guide (http://www.dtcenter.org/wrf-nmm/users/docs/user_guide/WPS/index.php).

 

Functionalities

 

The WRF Postprocessor v2.2,

-         is compatible with WRF version 2.2 and higher.

-         can be used to post-process both WRF-ARW and WRF-NMM forecasts. 

-         can ingest WRF history files (wrfout*) in two formats: netCDF and binary.

 

The WRF Postprocessor is divided into two parts, wrfpost and copygb:

 

wrfpost 

-         Interpolates the forecasts from the model’s native vertical coordinate to NWS standard output levels (pressure, height, etc.) and computes mean sea level pressure. If the requested field is on a model’s native level, then no vertical interpolation is performed.

-         Computes diagnostic output quantities.  A list of available fields is shown in Table 1.

-         Outputs the results in NWS and WMO standard GRIB1 format (for GRIB documentation, see http://www.nco.ncep.noaa.gov/pmb/docs/).

-         De-staggers the WRF-ARW forecasts from a C-grid to an A-grid.

-         Outputs two navigation files, copygb_nav.txt and copygb_hwrf.txt (these are ONLY used for WRF-NMM). 

 

 

copygb

-         Since wrfpost de-staggers WRF-ARW from a C-grid to an A-grid, WRF-ARW data can be displayed directly without going through copygb.

-         No de-staggering is applied when posting WRF-NMM forecasts. Therefore, the posted WRF-NMM output is still on the staggered native E-grid and must go through copygb to be interpolated to a regular non-staggered grid. 

-         copygb is only used by WRF-NMM - see the WRF-NMM User’s Guide (http://www.dtcenter.org/wrf-nmm/users/docs/user_guide/WPS/index.php).

 

 

An additional utility called ndate is distributed with the WRF Postprocessor tar-file.  This utility is used to format the dates of the forecasts to be posted for ingestion by the codes.

 

Computational Aspects and Supported Platforms

 

The WRF Postprocessor v2.2 has been tested on IBM and LINUX platforms. For LINUX, the Portland Group (PG) compiler has been used.

 

Only wrfpost has been parallelized, because it requires several 3-dimensional arrays for the computations.  When running wrfpost on more than one processor, the last processor will be designated as an I/O node, while the rest of the processors are designated as computational nodes. 

 

One limitation of the current version of the WRF Postprocessor is that only one forecast time can be processed per execution.

 

Directory Structure

 

Expanding “wrfpost_v2.2.tar” creates a main directory wrfpostprocV2 and five subdirectories:

sorc: contains source codes for wrfpost, ndate, and copygb.

scripts: contains sample running scripts

run_wrfpost: run wrfpost and copygb.

run_wrfpostandgempak: run wrfpost, copygb, and GEMPAK to plot various fields.

run_wrfpostandgrads: run wrfpost, copygb, and GrADS to plot various fields.

lib: contains source code subdirectories for the WRF Postprocessor libraries and is the directory where the WRF Postprocessor compiled libraries will reside.

w3lib: Library for coding and decoding data in GRIB format

Note: The version of this library included in this package is Endian- independent and can be used on LINUX and IBM systems.

iplib: General interpolation library (see lib/iplib/iplib.doc)

splib: Spectral transform library (see lib/splib/splib.doc)

wrfmpi_stubs: Contains some C and FORTRAN codes to generate the  libmpi.a library. It supports MPI implementation for LINUX applications.

parm: Contains the parameter files, which can be modified by the user to control how the post processing is performed.  

exec: Location of executables after compilation.

 

Setting up the WRF model to interface with the WRF Postprocessor

 

The wrfpost program is currently set up to read a large number of fields from the WRF model history (wrfout) files.  This configuration stems from NCEP's need to generate all of its required operational products. The program is configured such that is will run successfully if an expected input field is missing from the WRF history file as long as this field is not required to produce a requested output field.  If the pre-requisites for a requested output field are missing from the WRF history file, wrfpost will abort at run time. 

 

Take care not to remove fields from the wrfout files, which may be needed for diagnostical purposes by the WPP package. For example, if fields on isobaric surfaces are requested, but the pressure fields on model surfaces (PB and P) are not available in the history file, wrfpost will abort at run time.  In general the default fields available in the wrfout files are sufficient to run WPP.

 

Note that the wrfout files must contain only one frame per file.

 

Note: For WRF-ARW, the accumulated precipitation fields (RAINC and RAINNC) are run total accumulations, whereas the WRF-NMM accumulated precipitation fields (CUPREC and ACPREC) are zeroed every 6 hours.

 

Control File Overview

 

The user interacts with wrfpost through the control file, parm/wrf_cntrl.parm.  The control file is composed of a header and a body.  The header specifies the output file information. The body allows the user to select which fields and levels to process.

 

The header of the wrf_cntrl.parm file contains the following variables:

-         KGTYPE: defines output grid type, which should always be 255.

-         IMDLTY: identifies the process ID for AWIPS.

-         DATSET: defines the prefix used for the output file name. Currently set to “WRFPRS”.

 

The body of the wrf_cntrl.parm file is composed of a series of line pairs, for example:

 

(PRESS ON MDL SFCS   ) SCAL=( 3.0)

L=(11000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000)

 

where,

-         The first line specifies the field (e.g. PRESS) to process, the level type a user is interested in (e.g. ON MDL SFCS), and the degree of accuracy to be retained in the GRIB output (SCAL=3.0). 
A list of all possible output fields for wrfpost is provided in Table 1.  This table provides the full name of the variable in the first column and an abbreviated name in the second column.  The abbreviated names are used in the control file.  Note that the variable names also contain the type of level on which they are output.  For instance, temperature is available on “model surface” and “pressure surface”.

-         The second line specifies the levels on which the variable is to be processed.

 

Controlling which fields wrfpost outputs

 

To output a field, the body of the control file needs to contain an entry for the appropriate field and output for this field must be turned on for at least one level (see “Controlling which levels wrfpost outputs”).  If an entry for a particular field is not yet available in the control file, two lines may be added to the control file with the appropriate entries for that field. 

 

Controlling which levels wrfpost outputs

 

The second line of each pair determines which levels wrfpost will output. Output on a given level is turned off by a “0” or turned on by a “1”.

 

-         For isobaric output, 47 levels are possible, from 2 to 1013 hPa. The list of levels is specified in sorc/wrfpost/POSTDATA.f.

-         For model-level output, all model levels are possible, from the highest to the lowest.

-         For soil layers, the levels are 0-10 cm, 10-40 cm, 40-100 cm, and 100-200 cm. Note that these soil levels correspond to the levels used by the Noah LSM. When using another LSM, the soil quantities will be processed correctly but only the first four levels will be output and they will have depths of 0-10 cm, 10-40 cm, 40-100 cm, and 100-200 cm, regardless of which depths are actually used in the LSM.

-         For PBL layer averages, the levels correspond to 6 layers with a thickness of 30 hPa each.

-         For flight level, the levels are 914 m, 1524 m, 1829 m, 2134 m, 2743 m, 3658 m, and 6000 m.

-         For AGL RADAR Reflectivity, the levels are 4000 and 1000 m.

-         For surface or shelter-level output, only the first position of the line can be turned on.

 

For example, the sample control file parm/wrf_cntrl.parm has the following entry for surface dew point temperature:

 

(SURFACE DEWPOINT    ) SCAL=(-4.0)

L=(00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000)

 

Based on this entry, surface dew point temperature will not be output by wrfpost.  To add this field to the output, modify the entry to read:

 

(SURFACE DEWPOINT    ) SCAL=(-4.0)

L=(10000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000)

 

Running the WRF Postprocessor

 

The WRF Postprocessor package can be downloaded from:  http://www.dtcenter.org/wrf-nmm/users/downloads/

 

Unzip and untar the wrfpost tar file. This will create a directory called wrfpostprocV2.

 

cd wrfpostprocV2

 

Type configure, and provide the required info. For example:

 

./configure

 

Please select from the following supported platforms.

1. LINUX (PC)

2. AIX (IBM)

 

Enter selection [1-2]:          1


Enter your NETCDF path:

/usr/local/netcdf-pgi

Enter your WRF model source code path:

/home/user/WRFV2

"YOU HAVE SELECTED YOUR PLATFORM TO BE:" LINUX

 

 

To modify the default compiler options, edit the appropriate platform specific makefile (i.e. makefile_linux or makefile_ibm) and repeat the configure process.

 

From the wrfpostprocV2 directory, type make.  This command should create four WRF Postprocessor libraries (libmpi.a, libsp.a, libip.a, and libw3.a in lib/) and three WRF Postprocessor executables (wrfpost.exe, ndate.exe, and copygb.exe in exec/).

 

Note: The makefile included in the tar file currently only contains the setup for single processor compilation of wrfpost for LINUX.  Those users wanting to implement the parallel capability of this portion of the package will need to modify the compile options for wrfpost in the makefile.

 

 

Three scripts for running the WRF Postprocessor package are included in the tar file:

run_wrfpost (runs wrfpost and copygb)

run_wrfpostandgrads (runs wrfpost, copygb and GrADS)

run_wrfpostandgempak (runs wrfpost and copygb and GEMPAK)

 

The WRF Postprocessor should be run with one of these scripts. After selecting one of the scripts, it is necessary to edit the script to customize the following variables:

 

-         TOP_DIR: top level directory for source codes (WRF-POSTPROC and WRFV2).

-         DOMAINPATH: top level directory of WRF model run.

-         NOTE: The scripts are configured such that wrfpost expects the WRF history files (wrfout* files) to be in subdirectory wrfprd, the wrf_cntrl.parm file to be in the subdirectory parm and the Postprocessor working directory to be a subdirectory postprd under DOMAINPATH.

-         startdate: YYYYMMDDHH of forecast cycle to be post-processed.

-         fhr: first forecast hour to be post-processed.

-         lastfhr: last forecast hour to be post-processed.

-         incrementhr: increment (in hours) between forecast files.

-         gridno: grid to interpolate WRF model output to (this variable is only used if the forecast will be interpolated onto a standard AWIPS grid).

-         GEMEXEC: Defines a path name for GEMPAK related executables, if run_wrfpostandgempak is used.

 

 

Before running any of the above listed scripts, perform the following instructions:

 

cd to your DOMAINPATH directory.

 

Make a directory to put the WRF Postprocessor results.

mkdir postprd

 

Make a directory to put a copy of wrf_cntrl.parm file.

mkdir  parm

cd parm

 

Copy over default wrfpostproc_v2/parm/wrf_cntrl.parm  to customize wrfpost.. Edit wrf_cntrl.parm file to reflect the fields and levels the user wants wrfpost to output.

 

Once these directories are set up and the edits outlined above are completed, the scripts can be run interactively from the scripts directory by simply typing the script name on the command line.

 

Overview of the steps in script run_wrfpost to run the WRF Postprocessor

 

Note: It is recommended that the user refer to the script while reading this overview.

 

1.      Set up environmental variables TOP_DIR and DOMAINPATH.

2.      Define location of the post-processor executables.

3.      cd to working directory for post-processor (sample script assumes the working directory is the subdirectory “postprd” of DOMAINPATH).

4.      Link control file ../parm/wrf_control.parm and microphysical table ${WRFPATH}/test/run/ETAMP_DATA to working directory.

5.      Set up how many domains will be postprocessed.

                  For runs with a single domain, use “for domain d01”.

                  For runs with multiple domains, use “for domain d01 d02 .. dnn”.

6.      Set up grid to be posted to (see description under run copygb).

7.      Set up loop for forecast hours to be post-processed.

8.      Create namelist itag that will be read in by wrfpost.exe from stdin (unit 5). This namelist contains 4 lines:

                                   i.            Name of the WRF output file to be posted.

                                 ii.            Format of WRF model output (netcdf or binary).

                                iii.            Forecast valid time (not model start time) in WRF format.

                               iv.            Model name (NMM or NCAR, where NCAR refers to the WRF-ARW core).

9.      Run wrfpost and check for errors. The execution command in the distributed scripts is for a single processor wrfpost.exe < itag > outpost. To run wrfpost on multiple processors, the command line should be:

-     LINUX-MPI systems: mpirun -np N wrfpost.exe < itag > outpost

-     IBM: poe wrfpost.exe < itag > outpost

 

 

If scripts run_wrfpostandgrads or run_wrfpostandgempak are used, additional steps are taken to create image files (see Visualization section below).

 

Upon a successful run, wrfpost will generate the output file WRFPRS_dnn.hh (linked to wrfpr_dnn.hh), in the post-processor working directory, where “nn” is the domain ID and “hh” the forecast hour.  In addition, the script run_wrfpostandgrads will produce a suite of gif images named variablehh_dnn_GrADS.gif, and the script run_wrfpostandgempak will produce a suite of gif images named variable_dnn_hh.gif. 

 

If the run did not complete successfully, a log file in the post-processor working directory called wrfpost_dnn.hh.out, where “nn” is the domain ID and “hh” is the forecast hour, may be consulted for further information.

 

Visualization

 

GEMPAK

 

The GEMPAK utility nagrib is able to decode GRIB files whose navigation is on any non-staggered grid.  Hence, GEMPAK is able to decode GRIB files generated by the WRF Postprocessing package and plot horizontal fields or vertical cross sections. 

A sample script named run_wrfpostandgempak, which is included in the scripts directory of the tar file, can be used to run wrfpost and plot the following fields using GEMPAK:

 

·        Sfcmap.gif: mean SLP and 6 hourly precipitation

·        PrecipType.gif: precipitation type (just snow and rain)

·        850mbRH.gif: 850 mb relative humidity

·        850mbTempandWind.gif: 850 mb temperature and wind vectors

·        500mbHandVort.gif: 500 mb geopotential height and vorticity

·        250mbWindandH.gif: 250 mb wind speed isotacs and geopotential height

 

This script can be modified to customize fields for output. GEMPAK has an online users guide at http://my.unidata.ucar.edu/content/software/gempak/index.html

 

In order to use the script run_wrfpostandgempak, it is necessary to set the environment variable GEMEXEC to the path of the GEMPAK executables. For example,

setenv GEMEXEC /usr/local/gempak/bin

 

GrADS

 

The GrADS utilities grib2ctl.pl and gribmap are able to decode GRIB files whose navigation is on any non-staggered grid.  These utilities and instructions on how to use them to generate GrADS control files are available from: http://www.cpc.ncep.noaa.gov/products/wesley/grib2ctl.html.

The GrADS package is available from: http://grads.iges.org/grads/grads.html. 

GrADS has an online Users’ Guide at: http://grads.iges.org/grads/gadoc/.

A list of basic commands for GrADS can be found at: http://grads.iges.org/grads/gadoc/reference_card.pdf.

 

A sample script named run_wrfpostandgrads, which is included in the scripts directory of the WRF Postprocessing package, can be used to run wrfpost and plot the following fields using GrADS: 

 

·        Sfcmaphh.gif: mean SLP and 6-hour accumulated precipitation.

·        850mbRH.gif: 850 mb relative humidity

·        850mbTempandWind.gif: 850 mb temperature and wind vectors

·        500mbHandVort.gif: 500 mb geopotential heights and absolute vorticity

·        250mbWindandH.gif: 250 mb wind speed isotacs and geopotential heights

 

In order to use the script run_wrfpostandgrads, it is necessary to:

 

1.      Set environmental variable GADDIR to the path of the GrADS fonts and auxiliary files. For example,

setenv GADDIR /usr/local/grads/data

 

2.      Add the location of the GrADS executables to the PATH. For example

setenv PATH /usr/local/grads/bin:$PATH

 

3.      Link script cbar.gs to the post-processor working directory. (This script is provided in WRF-POSTPROC package, and run_wrfpostandgrads script makes a link from “scripts” directory to the run directory.) To generate the plots above, GrADS script cbar.gs is invoked. This script can also be obtained from the GrADS library of scripts at http://grads.iges.org/grads/gadoc/library.html.

 

Fields produced by the WRF Postprocessor

 

Table 1 lists basic and derived fields that are currently produced by wrfpost. The abbreviated names listed in the second column describe how the fields should be entered in the control file (wrf_cntrl.parm).

 

Table 1: Fields produced by wrfpost (column 1), abbreviated names used in wrfpost control file (column 2), corresponding GRIB identification number for the field (column 3), and corresponding GRIB identification number for the vertical coordinate (column 4).

 

Field name

Name in control file

Grib ID

Vertical level

Radar reflectivity on model surface

RADAR REFL MDL SFCS

211

109

Pressure on model surface

PRESS ON MDL SFCS

1

109

Height on model surface

HEIGHT ON MDL SFCS

7

109

Temperature on model surface

TEMP ON MDL SFCS

11

109

Potential temperature on model surface

POT TEMP ON MDL SFCS

13

109

Dew point temperature on model surface

DWPT TEMP ON MDL SFC

17

109

Specific humidity on model surface

SPEC HUM ON MDL SFCS

51

109

Relative humidity on model surface

REL HUM ON MDL SFCS

52

109

Moisture convergence on model surface

MST CNVG ON MDL SFCS

135

109

U component wind on model surface

U WIND ON MDL SFCS

33

109

V component wind on model surface

V WIND ON MDL SFCS

34

109

Cloud water on model surface

CLD WTR ON MDL SFCS

153

109

Cloud ice on model surface

CLD ICE ON MDL SFCS

58

109

Rain on model surface

RAIN ON MDL SFCS

170

109

Snow on model surface

SNOW ON MDL SFCS

171

109

Cloud fraction on model surface

CLD FRAC ON MDL SFCS

71

109

Omega on model surface

OMEGA ON MDL SFCS

39

109

Absolute vorticity on model surface

ABS VORT ON MDL SFCS

41

109

Geostrophic streamfunction on model surface

STRMFUNC ON MDL SFCS

35

109

Turbulent kinetic energy on model surface

TRBLNT KE ON MDL SFC

158

109

Richardson number on model surface

RCHDSN NO ON MDL SFC

254

109

Master length scale on model surface

MASTER LENGTH SCALE

226

109

Asymptotic length scale on model surface

ASYMPT MSTR LEN SCL

227

109

Radar reflectivity on pressure surface

RADAR REFL ON P SFCS

211

100

Height on pressure surface

HEIGHT OF PRESS SFCS

7

100

Temperature on pressure surface

TEMP ON PRESS SFCS

11

100

Potential temperature on pressure surface

POT TEMP ON P SFCS

13

100

Dew point temperature on pressure surface

DWPT TEMP ON P SFCS

17

100

Specific humidity on pressure surface

SPEC HUM ON P SFCS

51

100

Relative humidity on pressure surface

REL HUMID ON P SFCS

52

100

Moisture convergence on pressure surface

MST CNVG ON P SFCS

135

100

U component wind on pressure surface

U WIND ON PRESS SFCS

33

100

V component wind on pressure surface

V WIND ON PRESS SFCS

34

100

Omega on pressure surface

OMEGA ON PRESS SFCS

39

100

Absolute vorticity on pressure surface

ABS VORT ON P SFCS

41

100

Geostrophic streamfunction on pressure surface

STRMFUNC ON P SFCS

35

100

Turbulent kinetic energy on pressure surface

TRBLNT KE ON P SFCS

158

100

Cloud water on pressure surface

CLOUD WATR ON P SFCS

153

100

Cloud ice on pressure surface

CLOUD ICE ON P SFCS

58

100

Rain on pressure surface

RAIN ON P SFCS

170

100

Snow water on pressure surface

SNOW ON P SFCS

171

100

Total condensate on pressure surface

CONDENSATE ON P SFCS

135

100

Mesinger (Membrane) sea level pressure

MESINGER MEAN SLP

130

102

Shuell sea level pressure

SHUELL MEAN SLP

2

102

2 M pressure

SHELTER PRESSURE

1

105

2 M temperature

SHELTER TEMPERATURE

11

105

2 M specific humidity

SHELTER SPEC HUMID

51

105

2 M dew point temperature

SHELTER DEWPOINT

17

105

2 M RH

SHELTER REL HUMID

52

105

10 M u component wind

U WIND AT ANEMOM HT

33

105

10 M v component wind

V WIND AT ANEMOM HT

34

105

10 M potential temperature

POT TEMP AT 10 M

13

105

10 M specific humidity

SPEC HUM AT 10 M

51

105

Surface pressure

SURFACE PRESSURE

1

1

Terrain height

SURFACE HEIGHT

7

1

Skin potential temperature

SURFACE POT TEMP

13

1

Skin specific humidity

SURFACE SPEC HUMID

51

1

Skin dew point temperature

SURFACE DEWPOINT

17

1

Skin Relative humidity

SURFACE REL HUMID

52

1

Skin temperature

SFC (SKIN) TEMPRATUR

11

1

Soil temperature at the bottom of soil layers

BOTTOM SOIL TEMP

85

111

Soil temperature in between each of soil layers

SOIL TEMPERATURE

85

112

Soil moisture in between each of soil layers

SOIL MOISTURE

144

112

Snow water equivalent

SNOW WATER EQUIVALNT

65

1

Snow cover in percentage

PERCENT SNOW COVER

238

1

Heat exchange coeff at surface

SFC EXCHANGE COEF

208

1

Vegetation cover

GREEN VEG COVER

87

1

Soil moisture availability

SOIL MOISTURE AVAIL

207

112

Ground heat flux - instantaneous

INST GROUND HEAT FLX

155

1

Lifted index—surface based

LIFTED INDEX—SURFCE

131

101

Lifted index—best

LIFTED INDEX—BEST

132

116

Lifted index—from boundary layer

LIFTED INDEX—BNDLYR

24

116

CAPE

CNVCT AVBL POT ENRGY

157

1

CIN

CNVCT INHIBITION

156

1

Column integrated precipitable water

PRECIPITABLE WATER

54

200

Column integrated cloud water

TOTAL COLUMN CLD WTR

136

200

Column integrated cloud ice

TOTAL COLUMN CLD ICE

137

200

Column integrated rain

TOTAL COLUMN RAIN

138

200

Column integrated snow

TOTAL COLUMN SNOW

139

200

Column integrated total condensate

TOTAL COL CONDENSATE

140

200

Helicity

STORM REL HELICITY

190

106

U component storm motion

U COMP STORM MOTION

196

106

V component storm motion

V COMP STORM MOTION

197

106

Accumulated total precipitation

ACM TOTAL PRECIP

61

1

Accumulated convective precipitation

ACM CONVCTIVE PRECIP

63

1

Accumulated grid-scale precipitation

ACM GRD SCALE PRECIP

62

1

Accumulated snowfall

ACM SNOWFALL

65

1

Accumulated total snow melt

ACM SNOW TOTAL MELT

99

1

Precipitation type (4 types) - instantaneous

INSTANT PRECIP TYPE

140

1

Precipitation rate - instantaneous

INSTANT PRECIP RATE

59

1

Composite radar reflectivity

COMPOSITE RADAR REFL

212

200

Low level cloud fraction

LOW CLOUD FRACTION

73

214

Mid level cloud fraction

MID CLOUD FRACTION

74

224

High level cloud fraction

HIGH CLOUD FRACTION

75

234

Total cloud fraction

TOTAL CLD FRACTION

71

200

Time-averaged total cloud fraction

AVG TOTAL CLD FRAC

71

200

Time-averaged stratospheric cloud fraction

AVG STRAT CLD FRAC

213

200

Time-averaged convective cloud fraction

AVG CNVCT CLD FRAC

72

200

Cloud bottom pressure

CLOUD BOT PRESSURE

1

2

Cloud top pressure

CLOUD TOP PRESSURE

1

3

Cloud bottom height (above MSL)

CLOUD BOTTOM HEIGHT

7

2

Cloud top height (above MSL)

CLOUD TOP HEIGHT

7

3

Convective cloud bottom pressure

CONV CLOUD BOT PRESS

1

242

Convective cloud top pressure

CONV CLOUD TOP PRESS

1

243

Shallow convective cloud bottom pressure

SHAL CU CLD BOT PRES

1

248

Shallow convective cloud top pressure

SHAL CU CLD TOP PRES

1

249

Deep convective cloud bottom pressure

DEEP CU CLD BOT PRES

1

251

Deep convective cloud top pressure

DEEP CU CLD TOP PRES

1

252

Grid scale cloud bottom pressure

GRID CLOUD BOT PRESS

1

206

Grid scale cloud top pressure

GRID CLOUD TOP PRESS

1

207

Convective cloud fraction

CONV CLOUD FRACTION

72

200

Convective cloud efficiency

CU CLOUD EFFICIENCY

134

200

Above-ground height of LCL

LCL AGL HEIGHT

7

5

Pressure of LCL

LCL PRESSURE

1

5

Cloud top temperature

CLOUD TOP TEMPS

11

3

Temperature tendency from radiative fluxes

RADFLX CNVG TMP TNDY

216

109

Temperature tendency from shortwave radiative flux

SW RAD TEMP TNDY

250

109

Temperature tendency from longwave radiative flux

LW RAD TEMP TNDY

251

109

Outgoing surface shortwave radiation - instantaneous

INSTN OUT SFC SW RAD

211

1

Outgoing surface longwave radiation - instantaneous

INSTN OUT SFC LW RAD

212

1

Incoming surface shortwave radiation - time-averaged

AVE INCMG SFC SW RAD

204

1

Incoming surface longwave radiation - time-averaged

AVE INCMG SFC LW RAD

205

1

Outgoing surface shortwave radiation - time-averaged

AVE OUTGO SFC SW RAD

211

1

Outgoing surface longwave radiation - time-averaged

AVE OUTGO SFC LW RAD

212

1

Outgoing model top shortwave radiation - time-averaged

AVE OUTGO TOA SW RAD

211

8

Outgoing model top longwave radiation - time-averaged

AVE OUTGO TOA LW RAD

212

8

Incoming surface shortwave radiation - instantaneous

INSTN INC SFC SW RAD

204

1

Incoming surface longwave radiation - instantaneous

INSTN INC SFC LW RAD

205

1

Roughness length

ROUGHNESS LENGTH

83

1

Friction velocity

FRICTION VELOCITY

253

1

Surface drag coefficient

SFC DRAG COEFFICIENT

252

1

Surface u wind stress

SFC U WIND STRESS

124

1

Surface v wind stress

SFC V WIND STRESS

125

1

Surface sensible heat flux - time-averaged

AVE SFC SENHEAT FX

122

1

Ground heat flux - time-averaged

AVE GROUND HEAT FX

155

1

Surface latent heat flux - time-averaged

AVE SFC LATHEAT FX

121

1

Surface momentum flux - time-averaged

AVE SFC MOMENTUM FX

172

1

Accumulated surface evaporation

ACC SFC EVAPORATION

57

1

Surface sensible heat flux - instantaneous

INST SFC SENHEAT FX

122

1

Surface latent heat flux -  instantaneous

INST SFC LATHEAT FX

121

1

Latitude

LATITUDE

176

1

Longitude

LONGITUDE

177

1

Land sea mask (land=1, sea=0)

LAND SEA MASK

81

1

Sea ice mask

SEA ICE MASK

91

1

Surface midday albedo

SFC MIDDAY ALBEDO

84

1

Sea surface temperature

SEA SFC TEMPERATURE

80

1

Press at tropopause

PRESS AT TROPOPAUSE

1

7

Temperature at tropopause

TEMP AT TROPOPAUSE

11

7

Potential temperature at tropopause

POTENTL TEMP AT TROP

13

7

U wind at tropopause

U WIND AT TROPOPAUSE

33

7

V wind at tropopause

V WIND AT TROPOPAUSE

34

7

Wind shear at tropopause

SHEAR AT TROPOPAUSE

136

7

Height at tropopause

HEIGHT AT TROPOPAUSE

7

7

Temperature at flight levels

TEMP AT FD HEIGHTS

11

103

U wind at flight levels

U WIND AT FD HEIGHTS

33

103

V wind at flight levels

V WIND AT FD HEIGHTS

34

103

Freezing level height (above mean sea level)

HEIGHT OF FRZ LVL

7

4

Freezing level RH

REL HUMID AT FRZ LVL

52

4

Highest freezing level height

HIGHEST FREEZE LVL

7

204

Pressure in boundary layer (30 mb mean)

PRESS IN BNDRY LYR

1

116

Temperature in boundary layer (30 mb mean)

TEMP IN BNDRY LYR

11

116

Potential temperature in boundary layers (30 mb mean)

POT TMP IN BNDRY LYR

13

116

Dew point temperature in boundary layer (30 mb mean)

DWPT IN BNDRY LYR

17

116

Specific humidity in boundary layer (30 mb mean)

SPC HUM IN BNDRY LYR

51

116

RH in boundary layer (30 mb mean)

REL HUM IN BNDRY LYR

52

116

Moisture convergence in boundary layer (30 mb mean)

MST CNV IN BNDRY LYR

135

116

Precipitable water in boundary layer (30 mb mean)

P WATER IN BNDRY LYR

54

116

U wind in boundary layer (30 mb mean)

U WIND IN BNDRY LYR

33

116

V wind in boundary layer (30 mb mean)                        

V WIND IN BNDRY LYR        

34

116

Omega in boundary layer (30 mb mean)

OMEGA IN BNDRY LYR

39

116

Visibility

VISIBILITY

20

1

Vegetation type

VEGETATION TYPE

225

1

Soil type

SOIL TYPE

224

1

Canopy conductance

CANOPY CONDUCTANCE

181

1

PBL height

PBL HEIGHT

221

1

Slope type

SLOPE TYPE

222

1

Snow depth

SNOW DEPTH

66

1

Liquid soil moisture

LIQUID SOIL MOISTURE

160

112

Snow free albedo

SNOW FREE ALBEDO

170

1

Maximum snow albedo

MAXIMUM SNOW ALBEDO

159

1

Canopy water evaporation

CANOPY WATER EVAP

200

1

Direct soil evaporation

DIRECT SOIL EVAP

199

1

Plant transpiration

PLANT TRANSPIRATION

210

1

Snow sublimation

SNOW SUBLIMATION

198

1

Air dry soil moisture

AIR DRY SOIL MOIST

231

1

Soil moist porosity

SOIL MOIST POROSITY

240

1

Minimum stomatal resistance

MIN STOMATAL RESIST

203

1

Number of root layers

NO OF ROOT LAYERS

171

1

Soil moist wilting point

SOIL MOIST WILT PT

219

1

Soil moist reference

SOIL MOIST REFERENCE

230

1

Canopy conductance - solar component

CANOPY COND SOLAR

246

1

Canopy conductance - temperature component

CANOPY COND TEMP

247

1

Canopy conductance - humidity component

CANOPY COND HUMID

248

1

Canopy conductance - soil component

CANOPY COND SOILM

249

1

Potential evaporation

POTENTIAL EVAP

145

1

Heat diffusivity on sigma surface

DIFFUSION H RATE S S

182

107

Surface wind gust

SFC WIND GUST

180

1

Convective precipitation rate

CONV PRECIP RATE

214

1

Radar reflectivity at certain above ground heights

RADAR REFL AGL

211

105

 

 

 

read_wrf_nc utility

This utility allows a user to look at a WRF netCDF file at a glance.

 

What is the difference between this utility and the netCDF utility ncdump?

-         This utility has a large number of options, to allow a user to look at the specific part of the netCDF file in question.

-         The utility is written in Fortran 90, which will allow users to add options.

 

    

Obtain the read_wrf_nc utility from the WRF Download page (http://www2.mmm.ucar.edu/wrf/users/download/get_source.html)

 

Compile

The code has been ported to Dec Alpha, Linux, Mac (running xlf compiler), Sun, SGI and IBM

 

The code should run on any machine with a netCDF library (If you port the code to a different machine, please forward the compile flags to wrfhelp@ucar.edu)

 

To compile the code, use the compile flags at the top of the utility.
               e.g., for a LINUX  machine you need to type:
                pgf90    read_wrf_nc.f    -L/usr/local/netcdf/lib    -lnetcdf    -lm  

                  -I/usr/local/netcdf/include    -Mfree    -o read_wrf_nc

 

This will create the executable: read_wrf_nc

 

Run

 

read_wrf_nc   wrf_data_file_name   [-options]

 

               options :   [-h / help] [-att] [-m] [-M z] [-s] [-S x y z]
                                              [-v VAR] [-V VAR] [-w VAR]
                                              [-t t1 [t2]] [-times]
                                              [-ts xy X  Y   VAR VAR …..]
                                              [-ts xy lat lon VAR VAR …..]
                                              [-lev z] [-rot] [-diag]
                                              [-EditData VAR]


Options:      (Note: options [-att] ; [-t] and [-diag] can be used with other options)

-h / help

Print help information.

-att

Print global attributes.

-m

Print list of fields available for each time, plus the min and max values for each field.

-M z

Print list of fields available for each time, plus the min and max values for each field.
The min and max values of 3d fields will be for the z level of the field.

-s

Print list of fields available for each time, plus a sample value for each field.
Sample value is taken from the middle of model domain.

-S x y z

Print list of fields available for each time, plus a sample value for each field.
Sample value is at point x y z in the model domain.

-t t1 [t2]

Apply options only to times t1 to t2.
t2 is optional. If not set, options will only apply to t1.

-times

Print only the times in the file.

-ts

Generate time series output. A full vertical profile for each variables will be created.

-ts xy X  Y   VAR VAR …..

     will generate time series output for all VAR’s at location X/Y
-ts ll lat lon VAR VAR …..

     will generate time series output for all VAR’s at x/y location nearest to lat/lon

-lev z

Work only with option –ts
Will only create a time series for level z

-rot

Work only with option –ts

Will rotate winds to earth coordinates

-diag

Add if you want to see output for the diagnostics temperature (K), full model pressure and model height (tk,pressure,height)

-v VAR

Print basic information about field VAR.

-V VAR

Print basic information about field VAR, and dump the full field out to the screen.

-w VAR

Write the full field out to a file VAR.out

 

 

 

Default Options are [-att –s]

SPECIAL option : -EditData VAR

This option allows a user to read a WRF netCDF file, change a specific field and write it BACK into the WRF netCDF file.

This option will CHANGE your CURRENT WRF netCDF file so TAKE CARE when using this option.

ONLY one field at a time can be changed. So if you need 3 fields changed, you will need to run this program 3 times, each with a different "VAR"

IF you have multiple times in your WRF netCDF file – by default ALL times for variable "VAR" WILL be changed. If you only want to change one time period, also use the “-t” option.

HOW TO USE THIS OPTION:

Make a COPY of your WRF netCDF file before using this option

 

EDIT the subroutine USER_CODE

ADD an IF-statement block for the variable you want to change. This is to prevent a variable getting overwritten by mistake.

For REAL data arrays, work with array "data_real" and for INTEGER data arrays, work with the array "data_int".


Example 1:
If you want to change all (all time periods too) values of U to a constant 10.0 m/s, you would add the following IF-statement:
   elseif ( var == 'U') then
     data_real = 10.0

Example 2:
If you want to change a section of the LANDMASK data to SEA points:
   elseif ( var == 'LANDMASK') then
     data_real(10:15,20:25,1) = 0

Example 3:
Change all ISLTYP category 3 values into category 7 values (NOTE this is an INTEGER field):
   elseif ( var == 'ISLTYP') then
     where (data_int == 3 )
       data_int = 7
     endwhere

 

Compile and run program
You will be prompted if this is really what you want to do.
ONLY the answer "yes" will allow the change to take effect

iowrf utility

This utility allows a user to do some basic manipulation on WRF ARW netCDf files.

 

-         The utility allow one to thin the data, or extract a box from a data file.

 

    

Obtain the iowrf utility from the WRF Download page (http://www2.mmm.ucar.edu/wrf/users/download/get_source.html)

 

Compile

The code has been ported to Dec Alpha, Linux, Mac (running xlf compiler), Sun, SGI and IBM

 

The code should run on any machine with a netCDF library (If you port the code to a different machine, please forward the compile flags to wrfhelp@ucar.edu)

 

To compile the code, use the compile flags at the top of the utility.
               e.g., for a LINUX  machine you need to type:
                pgf90    iowrf.f    -L/usr/local/netcdf/lib    -lnetcdf    -lm  

                  -I/usr/local/netcdf/include    -Mfree    -o iowrf

 

This will create the executable: iowrf

 

Run

 

iowrf   wrf_data_file_name   [-options]

 

               options :   [-h / help]
                                              [-thina X] [-thin X] [-box {}]
                                              [-64bit]

 

-thina X

Thin the data with a ratio of 1:X
Data will be averaged before being fed back

-thin X

Thin the data with a ratio of 1:X

No averaging will be done

-box {}

Extract a box from the data file. X/Y/Z can be controlled independently. e.g.,

   -box x 10 30 y 10 30 z 5 15

   -box x 10 30 z 5 15

   -box y 10 30

   -box z 5 15

-64bit

Allow large files (> 2GB) to be read / write

Tools

Below is a list of tools that are freely available that can be used very successfully to manipulate model data (both WRF model data as well as other GRIB and netCDF datasets).

 

Converting Graphics

 

ImageMagick®

 

ImageMagick® is a software suite to create, edit, and compose bitmap images. It can read, convert and write images in a variety of formats (over 100) including DPX, EXR, GIF, JPEG, JPEG-2000, PDF, PhotoCD, PNG, Postscript, SVG, and TIFF. Use ImageMagick to translate, flip, mirror, rotate, scale, shear and transform images, adjust image colors, apply various special effects, or draw text, lines, polygons, ellipses and Bézier curves.

 

The software package is freely available from, http://www.imagemagick.org. Download and installation instructions are also available from this site.

 

Examples of converting data with ImageMagick® software:

convert                       file.pdf    file.png
convert       file.png   file.bmp
convert       file.pdf    file.gif
convert       file.ras    file.png

 

ImageMagick® cannot convert ncgm (NCAR Graphics) file format to other file formats.

 

 

Converting ncgm (NCAR Graphics) file format

 

NCAR Graphics has tools to convert ncgm files to raster file formats. Once files are in raster file format, ImageMagick® can be used to translate the files into other formats.

 

For ncgm files containing a single frame, use ctrans.

ctrans   -d sun   file.ncgm   >   file.ras


For ncgm files containing multiple frames, first use med (metafile frame editor) and then ctrans. med will create multiple single frame files called medxxx.ncgm

med -e '1,$ split $' file.ncgm
ctrans  -d sun  med001.ncgm > med001.ras

 

 

Converting ncgm (NCAR Graphics) files to gif images using ncgm2gif

 

This tool use to be very popular, but is becoming less so as other free tools are becoming available. This is not recommended for production of high quality images.

 

This script is available from: http://ngwww.ucar.edu/info/ncgm2gif

 

ncgm2gif   [options]   metafile

e.g.     ncgm2gif -res 500x500 -nomerge test.cgm

This will convert all images in test.cgm to 500x500 pixel gif images, called testxxx.gif

 

A compete list of options are available inside the ncgm2gif script (http://ngwww.ucar.edu/info/ncgm2gif)

 

Design WRF model domains.

 

WPS/util/plotgrids.exe, can be used to display model domains before WPS/geogrid.exe is run.

 

This utility reads the domain setup from the namelist.wps and create an ncgm file that can be viewed with the NCAR Graphics command “idt”, e.g,

 

   idt gmeta

 

Read more about this utility in Chapter 3 of this Users Guide.

 

Display ungrib (intermediate) files.

 

WPS/util/plotfmt.exe, can be used to display intermediate files created by WPS/ungrib.exe.

 

If you have created intermediate files manually, it is a very good practice to use this utility to display the data in your files first before running WPS/metgrid/exe.
Note: If you plan on manually creating intermediate files, refer to http://www2.mmm.ucar.edu/wrf/OnLineTutorial/WPS/IM_files.htm for detailed information about the file formats and sample programs.

 

This utility reads intermediate files and create an ncgm file that can be viewed with the NCAR Graphics command “idt”, e.g,

 

   idt gmeta

 

Read more about this utility in Chapter 3 of this Users Guide.

 

netCDF data

 

netCDF stands for network Common Data Form.

Most of the information below can be used for WRF netCDF data as well as other netCDF datasets.

netCDF is one of the current supported data formats chosen for WRF I/O API.

 

 

Advantages of using netCDF?

Most graphical packages support netCDF file formats

netCDF files are platform-independent (big_endian /  little_endian)

A lot of software already exist which can be used to process/manipulate netCDF data

 

 

Documentation:

http://www.unidata.ucar.edu/ (General netCDF documentation)

http://www.unidata.ucar.edu/software/netcdf/fguide.pdf  (NETCDF User’s Guide for FORTRAN)

 

 

Utilities:

ncdump

Part of the netCDF libraries. Reads a netCDF file and prints information about the dataset. e.g.

ncdump –h file  (print header information)
ncdump –v VAR  file (print header information and the full field VAR)  

ncdump –v Times  file  (a handy way to see how many times are available in a WRF output file)

 

ncview

Display netCDF data graphically. No overlays, no maps and no manipulation of data possible.
http://meteora.ucsd.edu/~pierce/ncview_home_page.html

 

ncBrowse

Display netCDF data graphically. Some overlays, maps and manipulation of data possible.
http://www.epic.noaa.gov/java/ncBrowse/

 

read_wrf_nc

A utility to display basic information for WRF netCDF files.

 

iowrf

A utility to do soma basic file manipulation on WRF netCDF files.

 

netCDF operators

http://nco.sourceforge.net/

Stand alone programs to, which can be used to manipulate data (performing grid point averaging / file differencing / file ‘appending’). Examples of the available operators are ncdiff, ncrcat, ncra, and ncks.

 

ncdiff

Difference two file, e.g.
ncdiff  input1.nc input2.nc output.nc

 

ncrcat

Write specified variables / times to a new file, e.g.
ncrcat  -v RAINNC wrfout* RAINNC.nc
ncrcat -d Time,0,231 -v  RAINNC   wrfout*  RAINNC.nc

 

ncra

Average variables and write to a new file, e.g.
ncra  -v OLR  wrfout*  OLR.nc

ncks (nc kitchen sink)

Combination of NCO tools all in one (handy: one tool for multiple operations)

 

GRIB data

 

Documentation

http://dss.ucar.edu/docs/formats/grib/gribdoc/  (Guide to GRIB 1)

http://www.nco.ncep.noaa.gov/pmb/docs/grib2/grib2_doc.shtml (Guide to GRIB2)
http://www.nco.ncep.noaa.gov/pmb/docs/grib2/GRIB2_parmeter_conversion_table.html (GRIB2 - GRIB1 parameter conversion table)

 

 

 

 

GRIB codes

 

It is important to understand the GRIB codes to know which fields are available in your dataset. For instance, NCEP uses the GRIB1 code 33 for the U-component of the wind, and 34 for the V-component. Other centers may use different codes, so always obtain the GRIB codes from the center you get your data from.

 

GRIB2 uses 3 codes for each field - product, category and parameter.
We would most often be interested in product 0 (Meteorological products). Category refers to the type of field, e.g., category 0 is temperature, category 1 is moisture and category 2 is momentum. Parameter is the field number.

So whereas GRIB1 only uses code 33 for the U-component of the wind, GRIB2 will use 0,2,2, for the U-component, and 0,2,3 for the V-component.

 

 

Display GRIB header/field information

 

GRIB1 data

WPS/util/g1print.exe

wgrib  (http://www.cpc.ncep.noaa.gov/products/wesley/wgrib.html)

 

 

GRIB2 data

WPS/util/g2print.exe

wgrib2 (http://www.cpc.ncep.noaa.gov/products/wesley/wgrib2/)

 

 

Convert GRIB1 data to netCDF format

ncl_grib2nc  (http://www.ncl.ucar.edu/Document/Tools)