C $Header: /u/gcmpack/MITgcm/pkg/exf/exf_getffieldrec.F,v 1.26 2014/06/07 17:50:34 jmc Exp $
C $Name: $
#include "EXF_OPTIONS.h"
SUBROUTINE EXF_GETFFIELDREC(
I fldstartdate, fldperiod,
I usefldyearlyfields,
O fac,
O first, changed,
O count0, count1, year0, year1,
I myTime, myIter, myThid )
c ==================================================================
c o Get flags, counters, and the linear interpolation factor for a
c given field.
c ==================================================================
IMPLICIT NONE
c == global variables ==
c cal: modelstart, modelstep
#include "EEPARAMS.h"
#include "cal.h"
#include "EXF_PARAM.h"
c == input arguments ==
c fldstartdate :: time in seconds of first fld record from the
c beginning of the model integration or, if
c usefldyearlyfields, from the beginning of year
c fldperiod :: period between forcing field records
c usefldyearlyfields :: when set, use yearly forcing files
c myTime :: current time in simulation
c myIter :: current iteration number in simulation
c myThid :: my thread identification number
_RL fldstartdate, fldperiod
logical usefldyearlyfields
_RL myTime
INTEGER myIter, myThid
c == output arguments ==
c fac :: weight of record count0 for linear interpolation purposes
c first :: model initialization flag: read two forcing records
c changed :: flag indicating that a new forcing record must be read
c count0 :: record number for forcing field preceding myTime
c count1 :: record number for forcing field following myTime
c year0 :: year of forcing file for record preceding myTime
c year1 :: year of forcing file for record following myTime
_RL fac
LOGICAL first, changed
INTEGER count0, count1, year0, year1
c == local variables ==
c mydate :: model date of current time step
c yearStartDate :: start of year date for flux record just before mydate
c difftime :: time difference between yearStartDate and mydate
c fldsectot :: time in seconds from fldstartdate to mydate
c fldsecs :: time from start of current forcing period to mydate
c fldsecs0 :: time from start of repeat period to mydate
c fldsecs1 :: time from end of current forcing period to mydate
c secondsInYear :: seconds in the flux year just before mydate
c myDateSeconds :: seconds from beginning of year to mydate
INTEGER mydate(4)
INTEGER yearStartDate(4)
INTEGER difftime(4)
_RL fldsectot, fldsecs, fldsecs0, fldsecs1
_RL secondsInYear, myDateSeconds
CHARACTER*(max_len_mbuf) msgBuf
c == external ==
INTEGER cal_IsLeap
EXTERNAL
c == end of interface ==
c Set some default values.
first = ((myTime - modelstart) .lt. 0.5*modelstep)
changed = .FALSE.
if ( fldperiod .eq. 0. _d 0 ) then
c Read field only once in the beginning. Hack: count1=count0 causes
c the model to read the first record twice, but since this this is
c done only the first time around it is not too much of an overhead.
first = ((myTime - modelstart) .lt. 0.5*modelstep)
changed = .FALSE.
fac = 1. _d 0
count0 = 1
count1 = count0
c Give these variables some unproblematic values although they are
c never used in this context.
year0 = 0
year1 = year0
else
c fldperiod .ne. 0
if (.not.usefldyearlyfields) then
c Determine offset in seconds from beginning of input data
c to current date.
fldsectot = myTime - fldstartdate
c Determine the flux records just before and after mycurrentdate.
if ( repeatPeriod .eq. 0. _d 0 ) then
if ( fldsectot .lt. 0. _d 0 ) then
WRITE(msgBuf,'(2A)') 'EXF_GetFFieldRec: ',
& 'myTime earlier than 1rst reccord (field-startdate)'
CALL PRINT_ERROR( msgBuf, myThid )
STOP 'ABNORMAL END: S/R EXF_GetFFieldRec'
endif
count0 = int((fldsectot+0.5)/fldperiod) + 1
count1 = count0 + 1
fldsecs = mod(fldsectot,fldperiod)
else
c if ( repeatPeriod .gt. 0. )
c If using repeating data then make fldsectot cycle around.
if(fldsectot.lt.0. _d 0) fldsectot = fldsectot + repeatPeriod
fldsecs0 = mod(fldsectot,repeatPeriod)
count0 = int((fldsecs0+0.5)/fldperiod) + 1
fldsecs1 = mod(fldsectot+fldperiod,repeatPeriod)
count1 = int((fldsecs1+0.5)/fldperiod) + 1
fldsecs = mod(fldsecs0,fldperiod)
endif
c Weight belonging to count0 for linear interpolation purposes.
fac = 1. - fldsecs/fldperiod
else
c if (usefldyearlyfields)
c Determine seconds from beginning of year to model current time.
call CAL_GETDATE( myIter, myTime, mydate, myThid )
year0 = int(mydate(1)/10000.)
yearStartDate(1) = year0 * 10000 + 101
yearStartDate(2) = 0
yearStartDate(3) = mydate(3)
yearStartDate(4) = mydate(4)
CALL CAL_TIMEPASSED(yearStartDate,mydate,difftime,myThid)
CALL CAL_TOSECONDS (difftime,myDateSeconds,myThid)
c Determine the flux year just before mycurrentdate.
if ( myDateSeconds .lt. fldstartdate ) year0 = year0 - 1
c Determine seconds in the flux year just before mycurrentdate.
secondsInYear = ndaysnoleap * secondsperday
if ( cal_IsLeap(year0,myThid) .eq. 2)
& secondsInYear = ndaysleap * secondsperday
c Determine the record just before mycurrentdate.
if ( myDateSeconds .lt. fldstartdate )
& myDateSeconds = myDateSeconds + secondsInYear
fldsectot = myDateSeconds - fldstartdate
count0 = int((fldsectot+0.5)/fldperiod) + 1
c Determine the flux year and record just after mycurrentdate.
year1 = year0
count1 = count0 + 1
if ( (fldstartdate+count0*fldperiod) .ge. secondsInYear ) then
year1 = year0 + 1
count1 = 1
endif
c Weight belonging to count0 for linear interpolation purposes.
fldsecs = mod(fldsectot,fldperiod)
fac = 1. - fldsecs/fldperiod
if ( year0 .ne. year1 )
& fac = 1. - fldsecs/(secondsInYear-(count0-1)*fldperiod)
endif
c if (usefldyearlyfields)
c Set switch for reading new record.
if ( fldsecs - modelstep .lt. 0. _d 0 ) changed = .TRUE.
endif
c if (fldperiod .eq. 0.)
RETURN
END