[gradsusr] ZDEF query

[Jennifer Adams]

On Aug 28, 2013, at 12:07 PM, M.Mahakur wrote:

> Respected All,
> 
> I have some sample ctl as below. The varibale 'mid' is at 6 levels. As I know GrADS consider the levels for 'mid' starting from z=1 i.e. 1000 hPa. In case mid variable actually available at 700 upto 200 hPa (total six), how can I modify this ctl for my case? In case I would like to avoid filling first two levels with undef with z=8 for 'mid' while creating the 'my_data.dat' file.
Sorry, but you cannot avoid padding your data file with missing values for the first two Z levels for the 'mid' variable and changing its Z size to 8 instead of 6. If not all Z levels are present, GrADS assumes the valid levels start at Z=1.
> 
>      DSET  my_data.dat 
>      TITLE Gridded Data Sample
>      UNDEF -9.99E33
>      XDEF 180 LINEAR 0.0  2.0 
>      YDEF  90 LINEAR -90  2.0 
>      ZDEF  10 LEVELS 1000 850 700 500 400 300 250 200 150 100 
>      TDEF   4 LINEAR 0Z10apr1991 12hr 
>      VARS      3
>      slp     0  99  sea level pressure 
>      hgt    10  99  heights 
>      mid     6  99  mid-level data
>      ENDVARS


> 
> 
> I have similar problem in GRIB file. When I display such variable it display "all undefine". I tried with 'd mid(z=1)', ' d mid(z=3' or 'd mid(lev=700)' but I could not. I can display when I create a different ctl file with -no_profile option.
For grib, the Z size of a variable creates a slot in the index file that may or may not be filled when you run gribmap. Use the verbose option when running gribmap and make sure that all the levels for that variable that are in your file match. Those levels that don't match (e.g. for 1000, 850, 150, and 100 mb) will just be set to missing. 
Jennifer

> 
> Kindly suggest.
> 
> Thank you.
> 
> With Regards,
> 
> Mahakur
> 
> _______________________________________________
> gradsusr mailing list
> gradsusr at gradsusr.org
> http://gradsusr.org/mailman/listinfo/gradsusr

--
Jennifer M. Adams
Center for Ocean-Land-Atmosphere Studies (COLA)
111 Research Hall, Mail Stop 2B3
George Mason University
4400 University Drive
Fairfax, VA 22030 





-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://gradsusr.org/pipermail/gradsusr/attachments/20130902/e438eca9/attachment-0003.html