[gradsusr] GFS plotting data from different files (different points of time) in one 2D (height – time) plot

[André Petersen]

Hi Jeff,

thank you very much vor your answer! I removed the commands "set t 1 2". 
Now I get a plot with the wind speed on the x-axis and the height on the 
y axis, see attachement.

What I want is, that it looks like this: 
http://www.atmos.albany.edu/facstaff/tang/forecast/fig/NAMM_WIND1.png

I really appreciate any further help!

Best regards, André

On 19.10.2014 11:55, Jeff Duda wrote:
> Andre,
> It looks like you have the right idea, but I don't see a reason for 
> the commands
>
> 'set t 1 2'
>
> That will cause grads to plot two different time steps worth of data.  
> Based on my knowledge of those GFS files, there is only one time slice 
> of data in each file, so depending on what the TDEF line of your 
> control file says, you should get an error on the second time slice.  
> Also, Grads does not overlay plots that vary in time, only plots that 
> are fixed in any two dimensions (X-Y for instance).
>
> Basically, remove the "set t 1 2' commands and see if the result is 
> what you are looking for.
>
> Jeff Duda
>
> On Sat, Oct 18, 2014 at 2:50 PM, André Petersen <mail at andrepetersen.de 
> <mailto:mail at andrepetersen.de>> wrote:
>
>     Dear subscriber,
>
>     I downloaded data from the american gfs weather modell (from
>     ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/gfs/prod/gfs.2014101812/master,
>     edit date if you read more than 1 month later).
>
>     I am using grads to plot data and it works fine if I plot data
>     from 1 timestep (=1 file) on a map. So my first try was to open
>     the first 2 files and to make a shaded plot showing areas with the
>     same wind speed in the same color. What I get is an empty plot
>     with correct axes.
>
>     |'open gfs.t12z.mastergrb2f00.ctl'
>
>     'open gfs.t12z.mastergrb2f03.ctl'
>
>     'set dfile 1'
>
>     'set time 12Z17OCT2014'
>     'set gxout shaded'
>     'set lat 50'
>     'set lon 0'
>     'set lev 1000 200'
>     'set t 1 2'
>     'd sqrt(ugrdprs*ugrdprs+vgrdprs*vgrdprs)*1.9438'
>
>     'set dfile 2'
>     'set time 15Z17OCT2014'
>     'set t 1 2'
>     'd sqrt(ugrdprs*ugrdprs+vgrdprs*vgrdprs)*1.9438'
>     |
>
>     I am using opengrads – Grid Analysis and Display System (GrADS)
>     Version 2.0.2.oga.2.
>
>     Anyone who can help me plotting data from different timesteps (=
>     different files) into one plot?
>
>     Best regards,
>     André Petersen
>
>
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>
>
>
> -- 
> Jeff Duda
> Graduate research assistant
> University of Oklahoma School of Meteorology
> Center for Analysis and Prediction of Storms
>
>
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