[gradsusr] wrf output data in lambert projection plot problem

Fu Kai sdfukai at gmail.com
Tue Feb 8 13:10:41 EST 2011


Hi, Jeff,

It is great to get your reply. I have tried the ARWpost program, but the
shape of the figure is almost the same, so I think the problem maybe
something else.

The header of ctl file created by ARWpost and the figure plotted by GrADS is
below, the wps namelist file is also attached.

The ctl file header:

dset ^test.dat
options  byteswapped
undef 1.e30
title  OUTPUT FROM WRF V3.0.1.1 MODEL
pdef   73  60 lcc  34.830  -81.030   37.000   30.500  60.00000  30.00000
-98.00000  30000.000  30000.000
xdef  224 linear  -94.99892   0.13513513
ydef  166 linear   23.26906   0.13513513
zdef   27 linear 1 1
tdef    5 linear 12Z24JAN2000     180MN

Test figure [image: case1ARWpost.png]

namelist.wps:

&share
 wrf_core = 'ARW',
 max_dom = 1,
 start_date = '2000-01-24_12:00:00',
 end_date   = '2000-01-25_12:00:00',
 interval_seconds = 21600
 io_form_geogrid = 2,
/
&geogrid
 parent_id         =   1,
 parent_grid_ratio =   1,
 i_parent_start    =   1,
 j_parent_start    =   1,
 e_we              =  74,
 e_sn              =  61,
 geog_data_res     = '10m',
 dx = 30000,
 dy = 30000,
 map_proj = 'lambert',
 ref_lat   =  34.83,
 ref_lon   = -81.03,
 truelat1  = 30.0,
 truelat2  =  60.0,
 stand_lon = -98.0,
 geog_data_path = '/home/kfu/WRF/WPS_GEOG/geog'
/


Thanks in advance.

Kai Fu


On Tue, Feb 8, 2011 at 12:20 PM, Jeffrey Duda <jdduda at iastate.edu> wrote:

> You're seeing that because the model grid itself has certain projection.
> It has nothing to do with how Grads is interpreting the data.  This is a WRF
> thing.  It doesn't look like a Lambert Conformal Conic projection, however,
> because I think if you do "set mproj lambert", your data should appear to be
> a rectangle with parallel edges and the map behind it should be altered.
> Your second figure does not show that, so perhaps you have some other
> projection.  I am also a WRF user, but I use the ARWpost program to convert
> WRF netCDF files to something Grads can read.  Since I don't use the
> wrf2grads program, there could be something with that program that caused
> the PDEF line in your control file to be something other than it is in the
> model.
>
> Jeff Duda
>
>   On Tue, Feb 8, 2011 at 10:41 AM, Fu Kai <sdfukai at gmail.com> wrote:
>
>>   Dear GrADS Users,
>>
>> I am beginner to wrf and GrADS, and want to display the output data of wrf
>> using GrADS, I used the wrf2grads program to get the ctl and dat file which
>> are needed by GrADS. When I tried to plot the data, there seems to be a
>> problem, the figure does not coincide with the lat and lon lines (Fig 1). I
>> thought it was because the case uses a lambert projection, while the default
>> projection used by GrADS seems to be Mercator, so I tried to use "set mproj
>> lambert" in GrADS, but only get a small figure (Fig 2) which also seems not
>> properly. Which command should I use to get a right figure.
>>
>> Any suggestion would be greatly appreciated.  The CTL file and the figure
>> plotted are below.  I'm a new GrADS user, so if this is a newbie problem, I
>> apologize in advance.
>>
>> CTL file created by wrf2grads program:
>>
>> dset ^wrfout_d01_2000-01-24_12:00:00.dat
>> undef 1.e35
>> pdef  73  60 lcc  28.171  -93.649    1.000    1.000  60.  30.  -98.000
>> 30000.  30000.
>> xdef  219 linear  -94.6   0.13513513
>> ydef  160 linear   23.6   0.13513513
>> zdef   27 levels
>>     0.02849
>>     0.09096
>>     0.17899
>>     0.29167
>>     0.43435
>>     0.61657
>>     0.83989
>>     1.17945
>>     1.62939
>>     2.10596
>>     2.60960
>>     3.34814
>>     4.30997
>>     5.27340
>>     6.23490
>>     7.19647
>>     8.16307
>>     9.13477
>>    10.11029
>>    11.10285
>>    12.13382
>>    13.21484
>>    14.34895
>>    15.53801
>>    16.78960
>>    18.11523
>>    19.52641
>> tdef         5 linear 12z24jan2000  1mn
>> vars    8
>> U               27 0 U Compoment of wind
>> V               27 0 V Component of wind
>> W               27 0 W Component of wind
>> THETA           27 0 Theta
>> TC              27 0 Temperature in C
>> P               27 0 Pressure (HPa)
>> Z               27 0 Height (m)
>> HGT             0  0 Terrain Height
>> endvars
>>
>> Fig. 1.
>> [image: wrfout_d01_2000-01-24_12_00_00.png]
>>
>> Fig. 2.
>> [image: wrfout_d01_2000-01-24_12_00_00lambert.png]
>>
>> Thanks in advance.
>>
>> Kai Fu
>>
>>
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>>
>>
>
>
> --
> Jeff Duda
> Iowa State University
> Meteorology Graduate Student
> 3134 Agronomy Hall
> www.meteor.iastate.edu/~jdduda
>
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>
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