& aqhfile, aqhstartdate, aqhperiod,
& aqhperiod, aqhstartdate,
_RL aqhstartdate
aqhstartdate = 0.
call CAL_TOSECONDS ( difftime, aqhstartdate ,mythid )
aqhstartdate = modelstart + aqhstartdate
& aqhstartdate