GEMPAK Manual | Programs


DCHRCN

    DCHRCN decodes forecast/advisory reports for tropical depressions,
    tropical storms and hurricanes for the Atlantic and Pacific Oceans
    from a real-time data feed, or from a file fed to the program 
    through standard input, and writes the data to an ASCII file.  The 
    program is controlled by inputs to the command line.

    The inputs are program options and the output file name or template.
    For example, for real-time data feeds:
    
	dchrcn [options] output_file

    If running the program interactively with standard input, the -c
    option must be used.  The input file must also be specified.
    For example:

	dchrcn -c YYMMDD/HHNN [other_options] output_file < input_file
    
    A template may be used to specify the output file name.  The file
    name template uses the date and time of the bulletin or report
    to replace the following characters.

	YYYY or YY	Year with or without the century
	MM		Month number
	DD		Day
	HH		Hour
	NN		Minute


     The format of the output ASCII file (with the 2 '|' lines given 
     below appearing as one line in the file) is as follows: 

     |Type|Valid_time|Name|Advisory_Number|Position_accuracy 
        |Direction|Speed|Minimum_Central_Press|Corr_flag
	     Lat    Lon    Type
	     Quadrant data

     Where: Type is TD (tropical depression), TS (tropical storm),
 	 	HU (hurricane) or HUT (typhoon).  If type is not 'HUT',
		an 'E' or 'S' is appended for an extratropical or 
		subtropical storm, respectively
	    Valid_time is the full GEMPAK date/time string
	    Name is the storm name
	    Advisory_number is the number assigned to the storm	
	    Position_accuracy is how close the center of the eye
		is to the given latitude and longitude
	    Direction is the direction that the storm is moving toward	
	    Speed is the speed of the storm in knots	
	    Minimum_Central_Press is the pressure value in mb in the eye
		at the valid time
	    Corr_flag is a flag indicating a correction (0 or 1)

     Extra spaces may appear anywhere in this line of information,
     except in the first character position.  The first character must
     be a bar (|).

     The current and forecast latitude and longitude values and storm
     type are read using the FORTRAN format (2F9.2,4X,A).

     Quadrant data (current 100 kt or 64 kt, 50 kt, and 34 kt winds and 
     12 ft seas, and forecast 100 kt or 64 kt, 50 kt and 34 kt winds) 
     are read using the FORTRAN format (4X,A).
 
     Prior to June 1, 2004, reports from the Joint Typhoon Warning
     Center (JTWC) included 100 kt winds instead of 64 kt winds.  As of
     June 1, 2004, the JTWC reports 64 kt winds, as do the TPC and CPHC.
     In the decoded quadrant sections, the first wind position,
     originally labelled as '64', is now labelled as 'MW', the maximum
     wind, where 'MW' represents either the 64 kt winds from any report
     or the 100 kt winds from Western Pacific (JTWC) reports issued
     before June 1, 2004.  If the storm type is 'HUT' and the date is
     prior to June 1, 2004, the first quadrant data is assumed to be the
     100 kt wind information.