[gradsusr] ZDEF query

[M.Mahakur]

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.

      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.

Kindly suggest.

Thank you.

With Regards,

Mahakur