MODULE sbcfwb !!====================================================================== !! *** MODULE sbcfwb *** !! Ocean fluxes : domain averaged freshwater budget !!====================================================================== !! History : OPA ! 2001-02 (E. Durand) Original code !! NEMO 1.0 ! 2002-06 (G. Madec) F90: Free form and module !! 3.0 ! 2006-08 (G. Madec) Surface module !! 3.2 ! 2009-07 (C. Talandier) emp mean s spread over erp area !! 3.6 ! 2014-11 (P. Mathiot ) add ice shelf melting !!---------------------------------------------------------------------- !!---------------------------------------------------------------------- !! sbc_fwb : freshwater budget for global ocean configurations (free surface & forced mode) !!---------------------------------------------------------------------- USE oce ! ocean dynamics and tracers USE dom_oce ! ocean space and time domain USE sbc_oce ! surface ocean boundary condition USE isf_oce , ONLY : fwfisf_cav, fwfisf_par ! ice shelf melting contribution USE sbc_ice , ONLY : snwice_mass, snwice_mass_b, snwice_fmass USE phycst ! physical constants USE sbcrnf ! ocean runoffs USE sbcssr ! Sea-Surface damping terms ! USE in_out_manager ! I/O manager USE iom ! IOM USE lib_mpp ! distribued memory computing library USE timing ! Timing USE lbclnk ! ocean lateral boundary conditions USE lib_fortran ! IMPLICIT NONE PRIVATE PUBLIC sbc_fwb ! routine called by step REAL(wp) :: rn_fwb0 ! initial freshwater adjustment flux [kg/m2/s] (nn_fwb = 2 only) REAL(wp) :: a_fwb ! annual domain averaged freshwater budget from the previous year REAL(wp) :: a_fwb_b ! annual domain averaged freshwater budget from the year before or at initial state REAL(wp) :: a_fwb_ini ! initial domain averaged freshwater budget REAL(wp) :: area ! global mean ocean surface (interior domain) !!---------------------------------------------------------------------- !! NEMO/OCE 4.0 , NEMO Consortium (2018) !! $Id$ !! Software governed by the CeCILL license (see ./LICENSE) !!---------------------------------------------------------------------- CONTAINS SUBROUTINE sbc_fwb( kt, kn_fwb, kn_fsbc, Kmm ) !!--------------------------------------------------------------------- !! *** ROUTINE sbc_fwb *** !! !! ** Purpose : Control the mean sea surface drift !! !! ** Method : several ways depending on kn_fwb !! =0 no control !! =1 global mean of emp set to zero at each nn_fsbc time step !! =2 annual global mean corrected from previous year !! =3 global mean of emp set to zero at each nn_fsbc time step !! & spread out over erp area depending its sign !! Note: if sea ice is embedded it is taken into account when computing the budget !!---------------------------------------------------------------------- INTEGER, INTENT( in ) :: kt ! ocean time-step index INTEGER, INTENT( in ) :: kn_fsbc ! INTEGER, INTENT( in ) :: kn_fwb ! ocean time-step index INTEGER, INTENT( in ) :: Kmm ! ocean time level index ! INTEGER :: ios, inum, ikty ! local integers REAL(wp) :: z_fwf, z_fwf_nsrf, zsum_fwf, zsum_erp ! local scalars REAL(wp) :: zsurf_neg, zsurf_pos, zsurf_tospread, zcoef ! - - REAL(wp), ALLOCATABLE, DIMENSION(:,:) :: ztmsk_neg, ztmsk_pos, z_wgt ! 2D workspaces REAL(wp), ALLOCATABLE, DIMENSION(:,:) :: ztmsk_tospread, zerp_cor ! - - REAL(wp) ,DIMENSION(1) :: z_fwfprv COMPLEX(dp),DIMENSION(1) :: y_fwfnow ! NAMELIST/namsbc_fwb/rn_fwb0 !!---------------------------------------------------------------------- ! IF( kt == nit000 ) THEN READ( numnam_ref, namsbc_fwb, IOSTAT = ios, ERR = 901 ) 901 IF( ios /= 0 ) CALL ctl_nam( ios, 'namsbc_fwb in reference namelist' ) READ( numnam_cfg, namsbc_fwb, IOSTAT = ios, ERR = 902 ) 902 IF( ios > 0 ) CALL ctl_nam( ios, 'namsbc_fwb in configuration namelist' ) IF(lwm) WRITE( numond, namsbc_fwb ) IF(lwp) THEN WRITE(numout,*) WRITE(numout,*) 'sbc_fwb : FreshWater Budget correction' WRITE(numout,*) '~~~~~~~' IF( kn_fwb == 1 ) WRITE(numout,*) ' instantaneously set to zero' IF( kn_fwb == 3 ) WRITE(numout,*) ' fwf set to zero and spread out over erp area' IF( kn_fwb == 2 ) THEN WRITE(numout,*) ' adjusted from previous year budget' WRITE(numout,*) WRITE(numout,*) ' Namelist namsbc_fwb' WRITE(numout,*) ' Initial freshwater adjustment flux [kg/m2/s] = ', rn_fwb0 END IF ENDIF ! IF( kn_fwb == 3 .AND. nn_sssr /= 2 ) CALL ctl_stop( 'sbc_fwb: nn_fwb = 3 requires nn_sssr = 2, we stop ' ) IF( kn_fwb == 3 .AND. ln_isfcav ) CALL ctl_stop( 'sbc_fwb: nn_fwb = 3 with ln_isfcav = .TRUE. not working, we stop ' ) ! area = glob_sum( 'sbcfwb', e1e2t(:,:) * tmask(:,:,1)) ! interior global domain surface ! isf cavities are excluded because it can feedback to the melting with generation of inhibition of plumes ! and in case of no melt, it can generate HSSW. ! #if ! defined key_si3 && ! defined key_cice snwice_mass_b(:,:) = 0.e0 ! no sea-ice model is being used : no snow+ice mass snwice_mass (:,:) = 0.e0 snwice_fmass (:,:) = 0.e0 #endif ! ENDIF SELECT CASE ( kn_fwb ) ! CASE ( 1 ) !== global mean fwf set to zero ==! ! IF( MOD( kt-1, kn_fsbc ) == 0 ) THEN y_fwfnow(1) = local_sum( e1e2t(:,:) * ( emp(:,:) - rnf(:,:) - fwfisf_cav(:,:) - fwfisf_par(:,:) - snwice_fmass(:,:) ) ) CALL mpp_delay_sum( 'sbcfwb', 'fwb', y_fwfnow(:), z_fwfprv(:), kt == nitend - nn_fsbc + 1 ) z_fwfprv(1) = z_fwfprv(1) / area zcoef = z_fwfprv(1) * rcp emp(:,:) = emp(:,:) - z_fwfprv(1) * tmask(:,:,1) qns(:,:) = qns(:,:) + zcoef * sst_m(:,:) * tmask(:,:,1) ! account for change to the heat budget due to fw correction ! outputs IF( iom_use('hflx_fwb_cea') ) CALL iom_put( 'hflx_fwb_cea', zcoef * sst_m(:,:) * tmask(:,:,1) ) IF( iom_use('vflx_fwb_cea') ) CALL iom_put( 'vflx_fwb_cea', z_fwfprv(1) * tmask(:,:,1) ) ENDIF ! CASE ( 2 ) !== fw adjustment based on fw budget at the end of the previous year ==! ! simulation is supposed to start 1st of January IF( kt == nit000 ) THEN ! initialisation ! ! set the fw adjustment (a_fwb) IF ( ln_rstart .AND. iom_varid( numror, 'a_fwb_b', ldstop = .FALSE. ) > 0 & ! as read from restart file & .AND. iom_varid( numror, 'a_fwb', ldstop = .FALSE. ) > 0 ) THEN IF(lwp) WRITE(numout,*) 'sbc_fwb : reading freshwater-budget from restart file' CALL iom_get( numror, 'a_fwb_b', a_fwb_b ) CALL iom_get( numror, 'a_fwb' , a_fwb ) ! a_fwb_ini = a_fwb_b ELSE ! as specified in namelist IF(lwp) WRITE(numout,*) 'sbc_fwb : setting freshwater-budget from namelist rn_fwb0' a_fwb = rn_fwb0 a_fwb_b = 0._wp ! used only the first year then it is replaced by a_fwb_ini ! a_fwb_ini = glob_sum( 'sbcfwb', e1e2t(:,:) * ( ssh(:,:,Kmm) + snwice_mass(:,:) * r1_rho0 ) ) & & * rho0 / ( area * rday * REAL(nyear_len(1), wp) ) END IF ! IF(lwp) WRITE(numout,*) IF(lwp) WRITE(numout,*)'sbc_fwb : freshwater-budget at the end of previous year = ', a_fwb , 'kg/m2/s' IF(lwp) WRITE(numout,*)' freshwater-budget at initial state = ', a_fwb_ini, 'kg/m2/s' ! ELSE ! at the end of year n: ikty = nyear_len(1) * 86400 / NINT(rn_Dt) IF( MOD( kt, ikty ) == 0 ) THEN ! Update a_fwb at the last time step of a year ! It should be the first time step of a year MOD(kt-1,ikty) but then the restart would be wrong ! Hence, we make a small error here but the code is restartable a_fwb_b = a_fwb_ini ! mean sea level taking into account ice+snow a_fwb = glob_sum( 'sbcfwb', e1e2t(:,:) * ( ssh(:,:,Kmm) + snwice_mass(:,:) * r1_rho0 ) ) a_fwb = a_fwb * rho0 / ( area * rday * REAL(nyear_len(1), wp) ) ! convert in kg/m2/s ENDIF ! ENDIF ! IF( MOD( kt-1, kn_fsbc ) == 0 ) THEN ! correct the freshwater fluxes using previous year budget minus initial state zcoef = ( a_fwb - a_fwb_b ) emp(:,:) = emp(:,:) + zcoef * tmask(:,:,1) qns(:,:) = qns(:,:) - zcoef * rcp * sst_m(:,:) * tmask(:,:,1) ! account for change to the heat budget due to fw correction ! outputs IF( iom_use('hflx_fwb_cea') ) CALL iom_put( 'hflx_fwb_cea', -zcoef * rcp * sst_m(:,:) * tmask(:,:,1) ) IF( iom_use('vflx_fwb_cea') ) CALL iom_put( 'vflx_fwb_cea', -zcoef * tmask(:,:,1) ) ENDIF ! Output restart information IF( lrst_oce ) THEN IF(lwp) WRITE(numout,*) IF(lwp) WRITE(numout,*) 'sbc_fwb : writing FW-budget adjustment to ocean restart file at it = ', kt IF(lwp) WRITE(numout,*) '~~~~' CALL iom_rstput( kt, nitrst, numrow, 'a_fwb_b', a_fwb_b ) CALL iom_rstput( kt, nitrst, numrow, 'a_fwb', a_fwb ) END IF ! IF( kt == nitend .AND. lwp ) THEN WRITE(numout,*) 'sbc_fwb : freshwater-budget at the end of simulation (year now) = ', a_fwb , 'kg/m2/s' WRITE(numout,*) ' freshwater-budget at initial state = ', a_fwb_b, 'kg/m2/s' ENDIF ! CASE ( 3 ) !== global fwf set to zero and spread out over erp area ==! ! ALLOCATE( ztmsk_neg(jpi,jpj) , ztmsk_pos(jpi,jpj) , ztmsk_tospread(jpi,jpj) , z_wgt(jpi,jpj) , zerp_cor(jpi,jpj) ) ! IF( MOD( kt-1, kn_fsbc ) == 0 ) THEN ztmsk_pos(:,:) = tmask_i(:,:) ! Select <0 and >0 area of erp WHERE( erp < 0._wp ) ztmsk_pos = 0._wp ztmsk_neg(:,:) = tmask_i(:,:) - ztmsk_pos(:,:) ! ! fwf global mean (excluding ocean to ice/snow exchanges) z_fwf = glob_sum( 'sbcfwb', e1e2t(:,:) * ( emp(:,:) - rnf(:,:) - fwfisf_cav(:,:) - fwfisf_par(:,:) - snwice_fmass(:,:) ) ) / area ! IF( z_fwf < 0._wp ) THEN ! spread out over >0 erp area to increase evaporation zsurf_pos = glob_sum( 'sbcfwb', e1e2t(:,:)*ztmsk_pos(:,:) ) zsurf_tospread = zsurf_pos ztmsk_tospread(:,:) = ztmsk_pos(:,:) ELSE ! spread out over <0 erp area to increase precipitation zsurf_neg = glob_sum( 'sbcfwb', e1e2t(:,:)*ztmsk_neg(:,:) ) ! Area filled by <0 and >0 erp zsurf_tospread = zsurf_neg ztmsk_tospread(:,:) = ztmsk_neg(:,:) ENDIF ! zsum_fwf = glob_sum( 'sbcfwb', e1e2t(:,:) * z_fwf ) ! fwf global mean over <0 or >0 erp area !!gm : zsum_fwf = z_fwf * area ??? it is right? I think so.... z_fwf_nsrf = zsum_fwf / ( zsurf_tospread + rsmall ) ! ! weight to respect erp field 2D structure zsum_erp = glob_sum( 'sbcfwb', ztmsk_tospread(:,:) * erp(:,:) * e1e2t(:,:) ) z_wgt(:,:) = ztmsk_tospread(:,:) * erp(:,:) / ( zsum_erp + rsmall ) ! ! final correction term to apply zerp_cor(:,:) = -1. * z_fwf_nsrf * zsurf_tospread * z_wgt(:,:) ! !!gm ===>>>> lbc_lnk should be useless as all the computation is done over the whole domain ! CALL lbc_lnk( 'sbcfwb', zerp_cor, 'T', 1.0_wp ) ! emp(:,:) = emp(:,:) + zerp_cor(:,:) qns(:,:) = qns(:,:) - zerp_cor(:,:) * rcp * sst_m(:,:) ! account for change to the heat budget due to fw correction erp(:,:) = erp(:,:) + zerp_cor(:,:) ! outputs IF( iom_use('hflx_fwb_cea') ) CALL iom_put( 'hflx_fwb_cea', -zerp_cor(:,:) * rcp * sst_m(:,:) ) IF( iom_use('vflx_fwb_cea') ) CALL iom_put( 'vflx_fwb_cea', -zerp_cor(:,:) ) ! IF( lwp ) THEN ! control print IF( z_fwf < 0._wp ) THEN WRITE(numout,*)' z_fwf < 0' WRITE(numout,*)' SUM(erp+) = ', SUM( ztmsk_tospread(:,:)*erp(:,:)*e1e2t(:,:) )*1.e-9,' Sv' ELSE WRITE(numout,*)' z_fwf >= 0' WRITE(numout,*)' SUM(erp-) = ', SUM( ztmsk_tospread(:,:)*erp(:,:)*e1e2t(:,:) )*1.e-9,' Sv' ENDIF WRITE(numout,*)' SUM(empG) = ', SUM( z_fwf*e1e2t(:,:) )*1.e-9,' Sv' WRITE(numout,*)' z_fwf = ', z_fwf ,' Kg/m2/s' WRITE(numout,*)' z_fwf_nsrf = ', z_fwf_nsrf ,' Kg/m2/s' WRITE(numout,*)' MIN(zerp_cor) = ', MINVAL(zerp_cor) WRITE(numout,*)' MAX(zerp_cor) = ', MAXVAL(zerp_cor) ENDIF ENDIF DEALLOCATE( ztmsk_neg , ztmsk_pos , ztmsk_tospread , z_wgt , zerp_cor ) ! CASE DEFAULT !== you should never be there ==! CALL ctl_stop( 'sbc_fwb : wrong nn_fwb value for the FreshWater Budget correction, choose either 1, 2 or 3' ) ! END SELECT ! END SUBROUTINE sbc_fwb !!====================================================================== END MODULE sbcfwb