_RL swfluxstartdate
& swfluxperiod, swfluxstartdate,
& swfluxfile, swfluxstartdate, swfluxperiod,
CALL CAL_TOSECONDS ( difftime, swfluxstartdate ,myThid)
swfluxstartdate = modelstart + swfluxstartdate
swfluxstartdate = 0.
& swfluxstartdate