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C18 PERIODIC FORCING (TIDAL) SURF ELEV OR PRESSURE ON SOUTH OPEN BOUNDARIES
* IPBS: I CELL INDEX OF BOUNDARY CELL
* JPBS: J CELL INDEX OF BOUNDARY CELL
* ISPBS: 0 FOR ELEVATION SPECIFIED
* 1 FOR RADIATION-SEPARATION CONDITION, ZERO TANGENTIAL VELOCITY
* 2 FOR RADIATION-SEPARATION CONDITION, FREE TANGENTIAL VELOCITY
* 3 FOR ELEVATION SPECIFIED, FREE TANGENTIAL VELOCITY
* NPFORS: APPLY HARMONIC FORCING NUMBER NPFORS
* NPSERS: APPLY TIME SERIES FORCING NUMBER NPSERS
* NPSERS1: APPLY TIME SERIES FORCING NUMBER NPSERS1 FOR 2ND SERIES (NPFORT.GE.1)
* TPCOORDS: TANGENTIAL COORDINATE ALONG BOUNDARY (NPFORT.GE.1)
* GRPID: ID NUMBER OF BOUNDARY GROUP
*
C18 IPBS JPBS ISPBS NPFORS NPSERS GRPID ! ID