DSET merged_h500.grads
undef 9.99e+20 
TITLE Selected daily cases
XDEF  144  LINEAR 0 2.5
YDEF  73  LINEAR -90 2.5
ZDEF 1 LEVELS 500
TDEF 731 LINEAR 00z01Jan1948 1dy
VARS 1
h    0  99  Geopotential Height (m)
ENDVARS