[gradsusr] rainfall rate script

[Charles Seman - NOAA Federal]

Ben,

Think for the fwrite loop below, set i=1 to start... I should have 
looked at it more carefully...

Chuck

On 01/19/2016 06:58 PM, Charles Seman - NOAA Federal wrote:
> Ben,
>
> We have calculated WRF precip rates from variable RAINNC.
>
> You can try using code like (caution, has not been tested):
>
> *  Calculate the WRF precipitation rates from accumulated precip...
> *  convert WRF model accumulated precipitation from [mm] to [mm/day]
> *
> *  note, we can only go to "nt-1" because we do forward-in-time finite
> *  differences for the WRF model precipitation rate...
>
> nt = 6578    ;* or the # of time levels in your time series
> dt = 0.5    ;* 12 hours or 0.5 day
> 'set x 1'
> 'set y 1'
> 'set z 1'
> 'set t 1 'nt-1
> 'define pratec = (RAINC(t+1)-RAINC(t+0))/'dt
> 'define pratenc = (RAINNC(t+1)-RAINNC(t+0))/'dt
>
> then you can use pratec and pratenc (or whatever you call them)...
>
> you can plot the variables directly; try something like:
>
> legends = 'RAINC  RAINNC'
> colors  = ' 2     3'
> marks   = ' 0     0'
>
> while ( nv <= 2 )
>   c.nv = subwrd(colors,nv)
>   m.nv = subwrd(marks,nv)
>   l.nv = subwrd(legends,nv)
>   nv = nv + 1
> endwhile
>
> pmin = 1e6 ; pmax = -1e6
>
> 'set t 1 'nt-1
> 'set gxout stat'
> 'd pratec'
> min_max = sublin(result,8)
> minv = subwrd(min_max,4)
> maxv = subwrd(min_max,5)
> if( minv < pmin )
>    pmin = minv
> endif
> if( maxv > pmax )
>    pmax = maxv
> endif
> 'd pratenc'
> min_max = sublin(result,8)
> minv = subwrd(min_max,4)
> maxv = subwrd(min_max,5)
> if( minv < pmin )
>    pmin = minv
> endif
> if( maxv > pmax )
>    pmax = maxv
> endif
>
> 'set gxout line'
> 'set grads off'
>
> 'set vrange 'pmin' 'pmax
>
> 'set ccolor 'c.1
> 'set cmark  'm.1
> 'd pratec'
>
> 'set ccolor 'c.2
> 'set cmark  'm.2
> 'd pratenc'
>
> 'cbar_line -x 3 -y 6 -c 'c.1' 'c.2' -l 1 1 -m "'m.1'" "'m.2'" -t "'l.1'"
> "'l.2'" -p'
>
> note, the above code hasn't been tested, but it should give you some
> ideas of how to plot the variables... cbar_line can be found at
> http://cola.gmu.edu/grads/gadoc/library.html
>
> if you still want to write out a binary file, try adapting your code:
>
> 'set fwrite scm9yr12hr.daily.grads'
> 'set gxout fwrite'
> i=2
> while(i<nt)
>       'set t 'i
>       'd pratec'
>       'd pratenc'
>       i=i+1
> endwhile
> 'disable fwrite’
>
> see also http://cola.gmu.edu/grads/gadoc/aboutgriddeddata.html
>
> Hope this helps,
> Chuck
>
>
> On 01/16/2016 12:15 AM, Ben Stephens wrote:
>> Hi, I am writing a script that will take existing total accumulated
>> rainfall data (units of mm) and output daily rainfall rates (mm/day) for
>> both rainc and rainnc.  This is the single-column WRF model output so
>> there is only one grid point with 20 levels and 12-hour time increment.
>>   Here is the script I have so far:
>>
>> 'open scm9yr12hr.ctl'
>> 'set fwrite scm9yr12hr.daily.grads'
>> 'set gxout fwrite'
>> i=2
>> while(i<6578)
>>     'set t 'i
>>     'd rainc(t+2)-rainc'
>>     'd rainnc(t+2)-rainc'
>>     i=i+2
>> endwhile
>> 'disable fwrite’
>>
>> I am basically wondering what to do after running the script.  I open
>> GrADS and execute the script with a run command, and it generates the
>> given output file, but I have not been able to display the data,
>> assuming it is working correctly.  I tried to create a new control file
>> for the output, and it opens, and the data seem to be there but they are
>> clearly wrong.  I am getting numbers with huge exponents and so on.  Any
>> input on whether my script is written correctly or how to display my
>> output?
>>
>> Thanks!
>> Ben
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> _______________________________________________
>> gradsusr mailing list
>> gradsusr at gradsusr.org
>> http://gradsusr.org/mailman/listinfo/gradsusr
>>
>

-- 

Please note that Charles.Seman at noaa.gov should be considered my NOAA
email address, not cjs at gfdl.noaa.gov.

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