MRGDAT

     MRGDAT is a logical variable indicating whether sounding data is to be 
     merged or unmerged.  The type of unmerged data follows a slash:

		merge flag / unmerged data type

     The valid unmerged data types are:

	1	=	mandatory data below 100 mb  ( TTAA, PPAA, TRPA, 
			MXWA )
	2	=	mandatory and significant level data below 100 mb
			( TTAA, PPAA, TRPA, MXWA, TTBB, PPBB )
	3	=	mandatory and significant level data below and
			above 100 mb  ( TTAA, PPAA, TRPA, MXWA, TTBB, PPBB,
			TTCC, PPCC, TRPC, MXWC, TTDD, PPDD )

     The default is 3.  If the data is merged, the data type is ignored.

     When MRGDAT is used to create a sounding file, it indicates whether 
     the file is to contain merged or unmerged data.  Unmerged datasets 
     will store the data as separate parts.  Merged data sets contain 
     values for each parameter at each level.
 
     If MRGDAT is used in a program to list data, the data will be merged 
     if MRGDAT = YES.  If MRGDAT = NO, the separate parts requested by the 
     type will be listed.