1.2.25. card21

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C21 PERIODIC FORCING (TIDAL) SURF ELEV OR PRESSURE ON NORTH OPEN BOUNDARIES
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*  IPBN: SEE CARD 18
*  JPBN:
*  ISPBN:
*  NPFORN:
*  NPSERN:
*  TPCOORDN: 
*  GRPID: ID NUMBER OF BOUNDARY GROUP
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C21    IPBN    JPBN   ISPBN  NPFORN  NPSERN      GRPID ! ID