netcdf clouds {
types:
  byte enum cloud_t {Clear = 0, Cumulonimbus = 1, Stratus = 2, 
      Stratocumulus = 3, Cumulus = 4, Altostratus = 5, Nimbostratus = 6, 
      Altocumulus = 7, Missing = 127} ;
dimensions:
	time = UNLIMITED ; // (5 currently)
variables:
	cloud_t primary_cloud(time) ;
		cloud_t primary_cloud:_FillValue = Missing ;
data:

 primary_cloud = Clear, Stratus, Cumulus, _, Cumulonimbus ;
}