SNLIST lists upper air data from a sounding file for specified
vertical levels and stations.

INPUT PARAMETERS
 
    SNFILE    Sounding data file
    AREA      Data area
    DATTIM    Date/time
    SNPARM    Sounding parameter list
    STNDEX    Stability indices
    LEVELS    Vertical levels
    VCOORD    Vertical coordinate type
    OUTPUT    Output device/filename
    MRGDAT    Merge data file flag/part type
 
 

PROGRAM DESCRIPTION
 
    SNLIST lists parameters derived from an upper air data set for
    the requested stations and times.

    Parameters which can be computed at various levels in the
    data set should be specified in SNPARM.  Parameters which have
    a single value at the station, such as stability indices,
    should be specified in STNDEX.

    Any parameters which can be computed from the data set
    parameters may be listed.  If the vertical levels requested
    are not present in the data set, the data will be interpolated
    between existing levels.  Data will also be interpolated to a
    new vertical coordinate system, if requested.

    Data from an unmerged data set can be listed without
    being merged if MRGDAT is set to NO.  If unmerged data
    are listed, SNPARM, VCOORD and LEVELS will be ignored, except
    that parameter 'TEXT' is allowed for SNPARM.

    If the sounding file contains both decoded data and undecoded
    text data, both types can be listed by specifying parameter
    'TEXT' in the parameter list for either SNPARM or STNDEX.
    TEXT may appear anywhere in the list of parameters.  Only
    text data for parts TTAA, TTBB, PPBB and TTCC will be listed.

 
EXAMPLES
 
    1.	List the parameters in the data set for the stations IAD
	and ACY at the mandatory levels.  Also list the Showalter,
	lifted and K indices.

	SNFILE	 =  $GEMDATA/HRCBOB.SND
	AREA	 =  @iad;acy
	DATTIM	 =  last
	SNPARM	 =  dset
	STNDEX	 =  show;lift;kinx
	LEVELS	 =  man
	VCOORD	 =  pres
	OUTPUT	 =  t
	MRGDAT	 =  YES

    2.	List the unmerged data from IAD.

	SNFILE	 =  $GEMDATA/HRCBOB.SND
	AREA	 =  @iad
	DATTIM	 =  last
	SNPARM	 =  dset
	STNDEX	 =  show;lift;kinx
	LEVELS	 =  man
	VCOORD	 =  pres
	OUTPUT	 =  t
	MRGDAT	 =  no

    3.  List the pressure, mixing ratio, u- and v-wind components
        and the Montgomery stream function on the isentropic
        surfaces from 300 to 400 degrees in 10-degree increments.
        Change the station to ACY.

	SNFILE	 =  $GEMDATA/HRCBOB.SND
	AREA	 =  @acy
	DATTIM	 =  last
	SNPARM	 =  pres;mixr;uwnd;vwnd;psym
	STNDEX	 =
	LEVELS	 =  300-400-10
	VCOORD	 =  thta
	OUTPUT	 =  t
	MRGDAT	 =  yes

    4.	List the unmerged data and the undecoded text for station
	BOI.  Use a locally created sounding file containing both
	types of data called DATA.SND.

	SNFILE	 =  DATA.SND
	AREA	 =  @boi
	DATTIM	 =  last
	SNPARM	 =  text
	STNDEX	 =
	LEVELS	 =
	VCOORD	 =
	OUTPUT	 =  t
	MRGDAT	 =  no

ERROR MESSAGES
 
    [SNLIST  -1]    Fatal error initializing TAE.
    [SNLIST  -2]    Fatal error reading TAE parameters.
    [SNLIST  -3]    There are no parameters to be listed.
    [SNLIST  -4]    Level parameter ... cannot be computed.
    [SNLIST  -5]    Parm ... is character; cannot be listed.
    [SNLIST  -6]    Vertical coordinate ... cannot be computed.
    [SNLIST  -7]    Station parameter ... cannot be computed.
    [SNLIST  -8]    Parm ... is character; cannot be listed.
    [SNLIST  -9]    No stations reported at these times.
    [SNLIST -10]    Too many parameters; ... cannot be added.
    [SNLIST -11]    The data set is merged.
    [SNLIST -12]    No inputs for levels.
