DSET   ^mask_gra
*
UNDEF  -999.0
*
OPTIONS   big_endian
*
TITLE  land portion at 0.5 deg resolution
*
XDEF 720 LINEAR 0.25 0.5
*
YDEF 360 LINEAR -89.75 0.5
*
ZDEF  02 LEVELS 1 2
*
TDEF   1 LINEAR JAN1948 1mo
*
VARS 1
mask  1  99  elevation in m
ENDVARS