MODULE sbcdcy !!====================================================================== !! *** MODULE sbcdcy *** !! Ocean forcing: compute the diurnal cycle !!====================================================================== !! History : OPA ! 2005-02 (D. Bernie) Original code !! NEMO 2.0 ! 2006-02 (S. Masson, G. Madec) adaptation to NEMO !! 3.1 ! 2009-07 (J.M. Molines) adaptation to v3.1 !!---------------------------------------------------------------------- !!---------------------------------------------------------------------- !! sbc_dcy : solar flux at kt from daily mean, taking diurnal cycle into account !!---------------------------------------------------------------------- USE oce ! ocean dynamics and tracers USE phycst ! ocean physics USE dom_oce ! ocean space and time domain USE sbc_oce ! Surface boundary condition: ocean fields USE in_out_manager ! I/O manager USE lib_mpp ! MPP library USE timing ! Timing IMPLICIT NONE PRIVATE INTEGER, PUBLIC :: nday_qsr !: day when parameters were computed REAL(wp), ALLOCATABLE, SAVE, DIMENSION(:,:) :: raa , rbb , rcc , rab ! diurnal cycle parameters REAL(wp), ALLOCATABLE, SAVE, DIMENSION(:,:) :: rtmd, rdawn, rdusk, rscal ! - - - PUBLIC sbc_dcy ! routine called by sbc !!---------------------------------------------------------------------- !! NEMO/OPA 3.3 , NEMO-consortium (2010) !! $Id$ !! Software governed by the CeCILL licence (NEMOGCM/NEMO_CeCILL.txt) !!---------------------------------------------------------------------- CONTAINS INTEGER FUNCTION sbc_dcy_alloc() !!---------------------------------------------------------------------- !! *** FUNCTION sbc_dcy_alloc *** !!---------------------------------------------------------------------- ALLOCATE( raa (jpi,jpj) , rbb (jpi,jpj) , rcc (jpi,jpj) , rab (jpi,jpj) , & & rtmd(jpi,jpj) , rdawn(jpi,jpj) , rdusk(jpi,jpj) , rscal(jpi,jpj) , STAT=sbc_dcy_alloc ) ! IF( lk_mpp ) CALL mpp_sum ( sbc_dcy_alloc ) IF( sbc_dcy_alloc /= 0 ) CALL ctl_warn('sbc_dcy_alloc: failed to allocate arrays') END FUNCTION sbc_dcy_alloc FUNCTION sbc_dcy( pqsrin ) RESULT( zqsrout ) !!---------------------------------------------------------------------- !! *** ROUTINE sbc_dcy *** !! !! ** Purpose : introduce a diurnal cycle of qsr from daily values !! !! ** Method : see Appendix A of Bernie et al. 2007. !! !! ** Action : redistribute daily QSR on each time step following the diurnal cycle !! !! reference : Bernie, DJ, E Guilyardi, G Madec, JM Slingo, and SJ Woolnough, 2007 !! Impact of resolving the diurnal cycle in an ocean--atmosphere GCM. !! Part 1: a diurnally forced OGCM. Climate Dynamics 29:6, 575-590. !!---------------------------------------------------------------------- REAL(wp), DIMENSION(jpi,jpj), INTENT(in) :: pqsrin ! input daily QSR flux !! INTEGER :: ji, jj ! dummy loop indices REAL(wp) :: ztwopi, zinvtwopi, zconvrad REAL(wp) :: zlo, zup, zlousd, zupusd REAL(wp) :: zdsws, zdecrad, ztx, zsin, zcos REAL(wp) :: ztmp, ztmp1, ztmp2, ztest REAL(wp), DIMENSION(jpi,jpj) :: zqsrout ! output QSR flux with diurnal cycle !---------------------------statement functions------------------------ REAL(wp) :: fintegral, pt1, pt2, paaa, pbbb, pccc ! dummy statement function arguments fintegral( pt1, pt2, paaa, pbbb, pccc ) = & & paaa * pt2 + zinvtwopi * pbbb * SIN(pccc + ztwopi * pt2) & & - paaa * pt1 - zinvtwopi * pbbb * SIN(pccc + ztwopi * pt1) !!--------------------------------------------------------------------- ! IF( nn_timing == 1 ) CALL timing_start('sbc_dcy') ! ! Initialization ! -------------- ztwopi = 2._wp * rpi zinvtwopi = 1._wp / ztwopi zconvrad = ztwopi / 360._wp ! When are we during the day (from 0 to 1) zlo = ( REAL(nsec_day, wp) - 0.5_wp * rdttra(1) ) / rday zup = zlo + ( REAL(nn_fsbc, wp) * rdttra(1) ) / rday ! IF( nday_qsr == -1 ) THEN ! first time step only IF(lwp) THEN WRITE(numout,*) WRITE(numout,*) 'sbc_dcy : introduce diurnal cycle from daily mean qsr' WRITE(numout,*) '~~~~~~~' WRITE(numout,*) ENDIF ! allocate sbcdcy arrays IF( sbc_dcy_alloc() /= 0 ) CALL ctl_stop( 'STOP', 'sbc_dcy_alloc : unable to allocate arrays' ) ! Compute rcc needed to compute the time integral of the diurnal cycle rcc(:,:) = zconvrad * glamt(:,:) - rpi ! time of midday rtmd(:,:) = 0.5 - glamt(:,:) / 360. rtmd(:,:) = MOD( (rtmd(:,:) + 1.), 1. ) ENDIF ! If this is a new day, we have to update the dawn, dusk and scaling function !---------------------- ! 2.1 dawn and dusk ! nday is the number of days since the beginning of the current month IF( nday_qsr /= nday ) THEN ! save the day of the year and the daily mean of qsr nday_qsr = nday ! number of days since the previous winter solstice (supposed to be always 21 December) zdsws = REAL(11 + nday_year, wp) ! declination of the earths orbit zdecrad = (-23.5 * zconvrad) * COS( zdsws * ztwopi / REAL(nyear_len(1),wp) ) ! Compute A and B needed to compute the time integral of the diurnal cycle zsin = SIN( zdecrad ) ; zcos = COS( zdecrad ) DO jj = 1, jpj DO ji = 1, jpi ztmp = zconvrad * gphit(ji,jj) raa(ji,jj) = SIN( ztmp ) * zsin rbb(ji,jj) = COS( ztmp ) * zcos END DO END DO ! Compute the time of dawn and dusk ! rab to test if the day time is equal to 0, less than 24h of full day rab(:,:) = -raa(:,:) / rbb(:,:) DO jj = 1, jpj DO ji = 1, jpi IF ( ABS(rab(ji,jj)) < 1 ) THEN ! day duration is less than 24h ! When is it night? ztx = zinvtwopi * (ACOS(rab(ji,jj)) - rcc(ji,jj)) ztest = -rbb(ji,jj) * SIN( rcc(ji,jj) + ztwopi * ztx ) ! is it dawn or dusk? IF ( ztest > 0 ) THEN rdawn(ji,jj) = ztx rdusk(ji,jj) = rtmd(ji,jj) + ( rtmd(ji,jj) - rdawn(ji,jj) ) ELSE rdusk(ji,jj) = ztx rdawn(ji,jj) = rtmd(ji,jj) - ( rdusk(ji,jj) - rtmd(ji,jj) ) ENDIF ELSE rdawn(ji,jj) = rtmd(ji,jj) + 0.5 rdusk(ji,jj) = rdawn(ji,jj) ENDIF END DO END DO rdawn(:,:) = MOD( (rdawn(:,:) + 1._wp), 1._wp ) rdusk(:,:) = MOD( (rdusk(:,:) + 1._wp), 1._wp ) ! 2.2 Compute the scalling function: ! S* = the inverse of the time integral of the diurnal cycle from dawm to dusk DO jj = 1, jpj DO ji = 1, jpi IF ( ABS(rab(ji,jj)) < 1 ) THEN ! day duration is less than 24h IF ( rdawn(ji,jj) < rdusk(ji,jj) ) THEN ! day time in one part rscal(ji,jj) = fintegral(rdawn(ji,jj), rdusk(ji,jj), raa(ji,jj), rbb(ji,jj), rcc(ji,jj)) rscal(ji,jj) = 1. / rscal(ji,jj) ELSE ! day time in two parts rscal(ji,jj) = fintegral(0., rdusk(ji,jj), raa(ji,jj), rbb(ji,jj), rcc(ji,jj)) & & + fintegral(rdawn(ji,jj), 1., raa(ji,jj), rbb(ji,jj), rcc(ji,jj)) rscal(ji,jj) = 1. / rscal(ji,jj) ENDIF ELSE IF ( raa(ji,jj) > rbb(ji,jj) ) THEN ! 24h day rscal(ji,jj) = fintegral(0., 1., raa(ji,jj), rbb(ji,jj), rcc(ji,jj)) rscal(ji,jj) = 1. / rscal(ji,jj) ELSE ! No day rscal(ji,jj) = 0.e0 ENDIF ENDIF END DO END DO ! ztmp = rday / ( rdttra(1) * REAL(nn_fsbc, wp) ) rscal(:,:) = rscal(:,:) * ztmp ! ENDIF ! 3. update qsr with the diurnal cycle ! ------------------------------------ DO jj = 1, jpj DO ji = 1, jpi IF( ABS(rab(ji,jj)) < 1 ) THEN ! day duration is less than 24h ! IF( rdawn(ji,jj) < rdusk(ji,jj) ) THEN ! day time in one part zlousd = MAX(zlo, rdawn(ji,jj)) zlousd = MIN(zlousd, zup) zupusd = MIN(zup, rdusk(ji,jj)) zupusd = MAX(zupusd, zlo) ztmp = fintegral(zlousd, zupusd, raa(ji,jj), rbb(ji,jj), rcc(ji,jj)) zqsrout(ji,jj) = pqsrin(ji,jj) * ztmp * rscal(ji,jj) ! ELSE ! day time in two parts zlousd = MIN(zlo, rdusk(ji,jj)) zupusd = MIN(zup, rdusk(ji,jj)) ztmp1 = fintegral(zlousd, zupusd, raa(ji,jj), rbb(ji,jj), rcc(ji,jj)) zlousd = MAX(zlo, rdawn(ji,jj)) zupusd = MAX(zup, rdawn(ji,jj)) ztmp2 = fintegral(zlousd, zupusd, raa(ji,jj), rbb(ji,jj), rcc(ji,jj)) ztmp = ztmp1 + ztmp2 zqsrout(ji,jj) = pqsrin(ji,jj) * ztmp * rscal(ji,jj) ENDIF ELSE ! 24h light or 24h night ! IF( raa(ji,jj) > rbb(ji,jj) ) THEN ! 24h day ztmp = fintegral(zlo, zup, raa(ji,jj), rbb(ji,jj), rcc(ji,jj)) zqsrout(ji,jj) = pqsrin(ji,jj) * ztmp * rscal(ji,jj) ! ELSE ! No day zqsrout(ji,jj) = 0.e0 ENDIF ENDIF END DO END DO ! IF( nn_timing == 1 ) CALL timing_stop('sbc_dcy') ! END FUNCTION sbc_dcy !!====================================================================== END MODULE sbcdcy