MODULE limsbc !!====================================================================== !! *** MODULE limsbc *** !! computation of the flux at the sea ice/ocean interface !!====================================================================== !! History : - ! 2006-07 (M. Vancoppelle) LIM3 original code !! 3.0 ! 2008-03 (C. Tallandier) surface module !! - ! 2008-04 (C. Tallandier) split in 2 + new ice-ocean coupling !! 3.3 ! 2010-05 (G. Madec) decrease ocean & ice reference salinities in the Baltic sea !! ! + simplification of the ice-ocean stress calculation !! 4.0 ! 2011-02 (G. Madec) dynamical allocation !!---------------------------------------------------------------------- #if defined key_lim3 !!---------------------------------------------------------------------- !! 'key_lim3' LIM 3.0 sea-ice model !!---------------------------------------------------------------------- !! lim_sbc_alloc : allocate the limsbc arrays !! lim_sbc_init : initialisation !! lim_sbc_flx : updates mass, heat and salt fluxes at the ocean surface !! lim_sbc_tau : update i- and j-stresses, and its modulus at the ocean surface !!---------------------------------------------------------------------- USE par_oce ! ocean parameters USE par_ice ! ice parameters USE dom_oce ! ocean domain USE sbc_ice ! Surface boundary condition: sea-ice fields USE sbc_oce ! Surface boundary condition: ocean fields USE phycst ! physical constants USE albedo ! albedo parameters USE ice ! LIM sea-ice variables USE lbclnk ! ocean lateral boundary condition USE in_out_manager ! I/O manager USE lib_mpp ! MPP library USE wrk_nemo ! work arrays USE prtctl ! Print control USE cpl_oasis3, ONLY : lk_cpl IMPLICIT NONE PRIVATE PUBLIC lim_sbc_init ! called by ice_init PUBLIC lim_sbc_flx ! called by sbc_ice_lim PUBLIC lim_sbc_tau ! called by sbc_ice_lim REAL(wp) :: r1_rdtice ! = 1. / rdt_ice REAL(wp) :: epsi16 = 1.e-16_wp ! constant values REAL(wp) :: rzero = 0._wp REAL(wp) :: rone = 1._wp REAL(wp), ALLOCATABLE, SAVE, DIMENSION(:,:) :: utau_oce, vtau_oce ! air-ocean surface i- & j-stress [N/m2] REAL(wp), ALLOCATABLE, SAVE, DIMENSION(:,:) :: tmod_io ! modulus of the ice-ocean velocity [m/s] REAL(wp), ALLOCATABLE, SAVE, DIMENSION(:,:) :: soce_0 , sice_0 ! cst SSS and ice salinity (levitating sea-ice) !! * Substitutions # include "vectopt_loop_substitute.h90" !!---------------------------------------------------------------------- !! NEMO/LIM3 4.0 , UCL - NEMO Consortium (2011) !! $Id$ !! Software governed by the CeCILL licence (NEMOGCM/NEMO_CeCILL.txt) !!---------------------------------------------------------------------- CONTAINS INTEGER FUNCTION lim_sbc_alloc() !!------------------------------------------------------------------- !! *** ROUTINE lim_sbc_alloc *** !!------------------------------------------------------------------- ALLOCATE( soce_0(jpi,jpj) , utau_oce(jpi,jpj) , & & sice_0(jpi,jpj) , vtau_oce(jpi,jpj) , tmod_io(jpi,jpj), STAT=lim_sbc_alloc) ! IF( lk_mpp ) CALL mpp_sum( lim_sbc_alloc ) IF( lim_sbc_alloc /= 0 ) CALL ctl_warn('lim_sbc_alloc: failed to allocate arrays') END FUNCTION lim_sbc_alloc SUBROUTINE lim_sbc_flx( kt ) !!------------------------------------------------------------------- !! *** ROUTINE lim_sbc_flx *** !! !! ** Purpose : Update the surface ocean boundary condition for heat !! salt and mass over areas where sea-ice is non-zero !! !! ** Action : - computes the heat and freshwater/salt fluxes !! at the ice-ocean interface. !! - Update the ocean sbc !! !! ** Outputs : - qsr : sea heat flux: solar !! - qns : sea heat flux: non solar !! - emp : freshwater budget: volume flux !! - emps : freshwater budget: concentration/dillution !! - fr_i : ice fraction !! - tn_ice : sea-ice surface temperature !! - alb_ice : sea-ice alberdo (lk_cpl=T) !! !! References : Goosse, H. et al. 1996, Bul. Soc. Roy. Sc. Liege, 65, 87-90. !! Tartinville et al. 2001 Ocean Modelling, 3, 95-108. !!--------------------------------------------------------------------- INTEGER, INTENT(in) :: kt ! number of iteration ! INTEGER :: ji, jj ! dummy loop indices INTEGER :: ierr ! local integer INTEGER :: ifvt, i1mfr, idfr ! some switches INTEGER :: iflt, ial, iadv, ifral, ifrdv REAL(wp) :: zinda, zfons, zpme ! local scalars REAL(wp), POINTER, DIMENSION(:,:) :: zfcm1 , zfcm2 ! solar/non solar heat fluxes REAL(wp), POINTER, DIMENSION(:,:,:) :: zalb, zalbp ! 2D/3D workspace !!--------------------------------------------------------------------- CALL wrk_alloc( jpi, jpj, zfcm1 , zfcm2 ) IF( lk_cpl ) CALL wrk_alloc( jpi, jpj, jpl, zalb, zalbp ) !------------------------------------------! ! heat flux at the ocean surface ! !------------------------------------------! ! pfrld is the lead fraction at the previous time step (actually between TRP and THD) ! changed to old_frld and old ht_i DO jj = 1, jpj DO ji = 1, jpi zinda = 1.0 - MAX( rzero , SIGN( rone , - ( 1.0 - pfrld(ji,jj) ) ) ) ifvt = zinda * MAX( rzero , SIGN( rone, -phicif (ji,jj) ) ) !subscripts are bad here i1mfr = 1.0 - MAX( rzero , SIGN( rone , - ( at_i(ji,jj) ) ) ) idfr = 1.0 - MAX( rzero , SIGN( rone , ( 1.0 - at_i(ji,jj) ) - pfrld(ji,jj) ) ) iflt = zinda * (1 - i1mfr) * (1 - ifvt ) ial = ifvt * i1mfr + ( 1 - ifvt ) * idfr iadv = ( 1 - i1mfr ) * zinda ifral = ( 1 - i1mfr * ( 1 - ial ) ) ifrdv = ( 1 - ifral * ( 1 - ial ) ) * iadv ! switch --- 1.0 ---------------- 0.0 -------------------- ! ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ! zinda | if pfrld = 1 | if pfrld < 1 | ! -> ifvt| if pfrld old_ht_i ! i1mfr | if frld = 1 | if frld < 1 | ! idfr | if frld <= pfrld | if frld > pfrld | ! iflt | ! ial | ! iadv | ! ifral ! ifrdv ! computation the solar flux at ocean surface zfcm1(ji,jj) = pfrld(ji,jj) * qsr(ji,jj) + ( 1. - pfrld(ji,jj) ) * fstric(ji,jj) ! fstric Solar flux transmitted trough the ice ! qsr Net short wave heat flux on free ocean ! new line fscmbq(ji,jj) = ( 1.0 - pfrld(ji,jj) ) * fstric(ji,jj) ! computation the non solar heat flux at ocean surface zfcm2(ji,jj) = - zfcm1(ji,jj) & & + iflt * ( fscmbq(ji,jj) ) & ! total abl -> fscmbq is given to the ocean ! fscmbq and ffltbif are obsolete ! & + iflt * ffltbif(ji,jj) !!! only if one category is used & + ifral * ( ial * qcmif(ji,jj) + (1 - ial) * qldif(ji,jj) ) * r1_rdtice & & + ifrdv * ( qfvbq(ji,jj) + qdtcn(ji,jj) ) * r1_rdtice & & + fhmec(ji,jj) & ! new contribution due to snow melt in ridging!! & + fheat_rpo(ji,jj) & ! contribution from ridge formation & + fheat_res(ji,jj) ! fscmbq Part of the solar radiation transmitted through the ice and going to the ocean ! computed in limthd_zdf.F90 ! ffltbif Total heat content of the ice (brine pockets+ice) / delta_t ! qcmif Energy needed to bring the ocean surface layer until its freezing (ok) ! qldif heat balance of the lead (or of the open ocean) ! qfvbq i think this is wrong! ! ---> Array used to store energy in case of total lateral ablation ! qfvbq latent heat uptake/release after accretion/ablation ! qdtcn Energy from the turbulent oceanic heat flux heat flux coming in the lead IF ( num_sal == 2 ) zfcm2(ji,jj) = zfcm2(ji,jj) + & fhbri(ji,jj) ! new contribution due to brine drainage ! bottom radiative component is sent to the computation of the ! oceanic heat flux fsbbq(ji,jj) = ( 1.0 - ( ifvt + iflt ) ) * fscmbq(ji,jj) ! used to compute the oceanic heat flux at the next time step qsr(ji,jj) = zfcm1(ji,jj) ! solar heat flux qns(ji,jj) = zfcm2(ji,jj) - fdtcn(ji,jj) ! non solar heat flux ! ! fdtcn : turbulent oceanic heat flux !!gm this IF prevents the vertorisation of the whole loop IF ( ( ji == jiindx ) .AND. ( jj == jjindx) ) THEN WRITE(numout,*) ' lim_sbc : heat fluxes ' WRITE(numout,*) ' qsr : ', qsr(jiindx,jjindx) WRITE(numout,*) ' zfcm1 : ', zfcm1(jiindx,jjindx) WRITE(numout,*) ' pfrld : ', pfrld(jiindx,jjindx) WRITE(numout,*) ' fstric : ', fstric (jiindx,jjindx) WRITE(numout,*) WRITE(numout,*) ' qns : ', qns(jiindx,jjindx) WRITE(numout,*) ' zfcm2 : ', zfcm2(jiindx,jjindx) WRITE(numout,*) ' zfcm1 : ', zfcm1(jiindx,jjindx) WRITE(numout,*) ' ifral : ', ifral WRITE(numout,*) ' ial : ', ial WRITE(numout,*) ' qcmif : ', qcmif(jiindx,jjindx) WRITE(numout,*) ' qldif : ', qldif(jiindx,jjindx) WRITE(numout,*) ' qcmif / dt: ', qcmif(jiindx,jjindx) * r1_rdtice WRITE(numout,*) ' qldif / dt: ', qldif(jiindx,jjindx) * r1_rdtice WRITE(numout,*) ' ifrdv : ', ifrdv WRITE(numout,*) ' qfvbq : ', qfvbq(jiindx,jjindx) WRITE(numout,*) ' qdtcn : ', qdtcn(jiindx,jjindx) WRITE(numout,*) ' qfvbq / dt: ', qfvbq(jiindx,jjindx) * r1_rdtice WRITE(numout,*) ' qdtcn / dt: ', qdtcn(jiindx,jjindx) * r1_rdtice WRITE(numout,*) ' ' WRITE(numout,*) ' fdtcn : ', fdtcn(jiindx,jjindx) WRITE(numout,*) ' fhmec : ', fhmec(jiindx,jjindx) WRITE(numout,*) ' fheat_rpo : ', fheat_rpo(jiindx,jjindx) WRITE(numout,*) ' fhbri : ', fhbri(jiindx,jjindx) WRITE(numout,*) ' fheat_res : ', fheat_res(jiindx,jjindx) ENDIF !!gm end END DO END DO !------------------------------------------! ! mass flux at the ocean surface ! !------------------------------------------! !!gm optimisation: this loop have to be merged with the previous one DO jj = 1, jpj DO ji = 1, jpi ! case of realistic freshwater flux (Tartinville et al., 2001) (presently ACTIVATED) ! ------------------------------------------------------------------------------------- ! The idea of this approach is that the system that we consider is the ICE-OCEAN system ! Thus FW flux = External ( E-P+snow melt) ! Salt flux = Exchanges in the ice-ocean system then converted into FW ! Associated to Ice formation AND Ice melting ! Even if i see Ice melting as a FW and SALT flux ! ! computing freshwater exchanges at the ice/ocean interface zpme = - emp(ji,jj) * ( 1.0 - at_i(ji,jj) ) & ! evaporation over oceanic fraction & + tprecip(ji,jj) * at_i(ji,jj) & ! all precipitation reach the ocean & - sprecip(ji,jj) * ( 1. - (pfrld(ji,jj)**betas) ) & ! except solid precip intercepted by sea-ice & - rdmsnif(ji,jj) * r1_rdtice & ! freshwaterflux due to snow melting & + fmmec(ji,jj) ! snow falling when ridging ! computing salt exchanges at the ice/ocean interface ! sice should be the same as computed with the ice model zfons = ( soce_0(ji,jj) - sice_0(ji,jj) ) * rdmicif(ji,jj) * r1_rdtice ! SOCE zfons = ( sss_m (ji,jj) - sice_0(ji,jj) ) * rdmicif(ji,jj) * r1_rdtice !CT useless ! salt flux for constant salinity !CT useless fsalt(ji,jj) = zfons / ( sss_m(ji,jj) + epsi16 ) + fsalt_res(ji,jj) ! salt flux for variable salinity zinda = 1.0 - MAX( rzero , SIGN( rone , - ( 1.0 - pfrld(ji,jj) ) ) ) ! correcting brine and salt fluxes fsbri(ji,jj) = zinda*fsbri(ji,jj) ! converting the salt fluxes from ice to a freshwater flux from ocean fsalt_res(ji,jj) = fsalt_res(ji,jj) / ( sss_m(ji,jj) + epsi16 ) fseqv(ji,jj) = fseqv(ji,jj) / ( sss_m(ji,jj) + epsi16 ) fsbri(ji,jj) = fsbri(ji,jj) / ( sss_m(ji,jj) + epsi16 ) fsalt_rpo(ji,jj) = fsalt_rpo(ji,jj) / ( sss_m(ji,jj) + epsi16 ) ! freshwater mass exchange (positive to the ice, negative for the ocean ?) ! actually it's a salt flux (so it's minus freshwater flux) ! if sea ice grows, zfons is positive, fsalt also ! POSITIVE SALT FLUX FROM THE ICE TO THE OCEAN ! POSITIVE FRESHWATER FLUX FROM THE OCEAN TO THE ICE [kg.m-2.s-1] emp(ji,jj) = - zpme END DO END DO IF( num_sal == 2 ) THEN ! variable ice salinity: brine drainage included in the salt flux emps(:,:) = fsbri(:,:) + fseqv(:,:) + fsalt_res(:,:) + fsalt_rpo(:,:) + emp(:,:) ELSE ! constant ice salinity: emps(:,:) = fseqv(:,:) + fsalt_res(:,:) + fsalt_rpo(:,:) + emp(:,:) ENDIF !-----------------------------------------------! ! Storing the transmitted variables ! !-----------------------------------------------! fr_i (:,:) = at_i(:,:) ! Sea-ice fraction tn_ice(:,:,:) = t_su(:,:,:) ! Ice surface temperature !------------------------------------------------! ! Computation of snow/ice and ocean albedo ! !------------------------------------------------! IF( lk_cpl ) THEN ! coupled case CALL albedo_ice( t_su, ht_i, ht_s, zalbp, zalb ) ! snow/ice albedo ! alb_ice(:,:,:) = 0.5_wp * zalbp(:,:,:) + 0.5_wp * zalb (:,:,:) ! Ice albedo (mean clear and overcast skys) ENDIF IF(ln_ctl) THEN CALL prt_ctl( tab2d_1=qsr , clinfo1=' lim_sbc: qsr : ', tab2d_2=qns , clinfo2=' qns : ' ) CALL prt_ctl( tab2d_1=emp , clinfo1=' lim_sbc: emp : ', tab2d_2=emps, clinfo2=' emps : ' ) CALL prt_ctl( tab2d_1=fr_i , clinfo1=' lim_sbc: fr_i : ' ) CALL prt_ctl( tab3d_1=tn_ice, clinfo1=' lim_sbc: tn_ice : ', kdim=jpl ) ENDIF ! CALL wrk_dealloc( jpi, jpj, zfcm1 , zfcm2 ) IF( lk_cpl ) CALL wrk_dealloc( jpi, jpj, jpl, zalb, zalbp ) ! END SUBROUTINE lim_sbc_flx SUBROUTINE lim_sbc_tau( kt , pu_oce, pv_oce ) !!------------------------------------------------------------------- !! *** ROUTINE lim_sbc_tau *** !! !! ** Purpose : Update the ocean surface stresses due to the ice !! !! ** Action : * at each ice time step (every nn_fsbc time step): !! - compute the modulus of ice-ocean relative velocity !! (*rho*Cd) at T-point (C-grid) or I-point (B-grid) !! tmod_io = rhoco * | U_ice-U_oce | !! - update the modulus of stress at ocean surface !! taum = frld * taum + (1-frld) * tmod_io * | U_ice-U_oce | !! * at each ocean time step (every kt): !! compute linearized ice-ocean stresses as !! Utau = tmod_io * | U_ice - pU_oce | !! using instantaneous current ocean velocity (usually before) !! !! NB: - ice-ocean rotation angle no more allowed !! - here we make an approximation: taum is only computed every ice time step !! This avoids mutiple average to pass from T -> U,V grids and next from U,V grids !! to T grid. taum is used in TKE and GLS, which should not be too sensitive to this approximaton... !! !! ** Outputs : - utau, vtau : surface ocean i- and j-stress (u- & v-pts) updated with ice-ocean fluxes !! - taum : modulus of the surface ocean stress (T-point) updated with ice-ocean fluxes !!--------------------------------------------------------------------- INTEGER , INTENT(in) :: kt ! ocean time-step index REAL(wp), DIMENSION(jpi,jpj), INTENT(in) :: pu_oce, pv_oce ! surface ocean currents !! INTEGER :: ji, jj ! dummy loop indices REAL(wp) :: zat_u, zutau_ice, zu_t, zmodt ! local scalar REAL(wp) :: zat_v, zvtau_ice, zv_t ! - - !!--------------------------------------------------------------------- ! IF( MOD( kt-1, nn_fsbc ) == 0 ) THEN !== Ice time-step only ==! (i.e. surface module time-step) !CDIR NOVERRCHK DO jj = 2, jpjm1 !* update the modulus of stress at ocean surface (T-point) !CDIR NOVERRCHK DO ji = fs_2, fs_jpim1 ! ! 2*(U_ice-U_oce) at T-point zu_t = u_ice(ji,jj) + u_ice(ji-1,jj) - u_oce(ji,jj) - u_oce(ji-1,jj) zv_t = v_ice(ji,jj) + v_ice(ji,jj-1) - v_oce(ji,jj) - v_oce(ji,jj-1) ! ! |U_ice-U_oce|^2 zmodt = 0.25_wp * ( zu_t * zu_t + zv_t * zv_t ) ! ! update the ocean stress modulus taum(ji,jj) = ( 1._wp - at_i(ji,jj) ) * taum(ji,jj) + at_i(ji,jj) * rhoco * zmodt tmod_io(ji,jj) = rhoco * SQRT( zmodt ) ! rhoco * |U_ice-U_oce| at T-point END DO END DO CALL lbc_lnk( taum, 'T', 1. ) ; CALL lbc_lnk( tmod_io, 'T', 1. ) ! utau_oce(:,:) = utau(:,:) !* save the air-ocean stresses at ice time-step vtau_oce(:,:) = vtau(:,:) ! ENDIF ! ! !== every ocean time-step ==! ! DO jj = 2, jpjm1 !* update the stress WITHOUT a ice-ocean rotation angle DO ji = fs_2, fs_jpim1 ! Vect. Opt. zat_u = ( at_i(ji,jj) + at_i(ji+1,jj) ) * 0.5_wp ! ice area at u and V-points zat_v = ( at_i(ji,jj) + at_i(ji,jj+1) ) * 0.5_wp ! ! linearized quadratic drag formulation zutau_ice = 0.5_wp * ( tmod_io(ji,jj) + tmod_io(ji+1,jj) ) * ( u_ice(ji,jj) - pu_oce(ji,jj) ) zvtau_ice = 0.5_wp * ( tmod_io(ji,jj) + tmod_io(ji,jj+1) ) * ( v_ice(ji,jj) - pv_oce(ji,jj) ) ! ! stresses at the ocean surface utau(ji,jj) = ( 1._wp - zat_u ) * utau_oce(ji,jj) + zat_u * zutau_ice vtau(ji,jj) = ( 1._wp - zat_v ) * vtau_oce(ji,jj) + zat_v * zvtau_ice END DO END DO CALL lbc_lnk( utau, 'U', -1. ) ; CALL lbc_lnk( vtau, 'V', -1. ) ! lateral boundary condition ! IF(ln_ctl) CALL prt_ctl( tab2d_1=utau, clinfo1=' lim_sbc: utau : ', mask1=umask, & & tab2d_2=vtau, clinfo2=' vtau : ' , mask2=vmask ) ! END SUBROUTINE lim_sbc_tau SUBROUTINE lim_sbc_init !!------------------------------------------------------------------- !! *** ROUTINE lim_sbc_init *** !! !! ** Purpose : Preparation of the file ice_evolu for the output of !! the temporal evolution of key variables !! !! ** input : Namelist namicedia !!------------------------------------------------------------------- ! IF(lwp) WRITE(numout,*) IF(lwp) WRITE(numout,*) 'lim_sbc_init : LIM-3 sea-ice - surface boundary condition' IF(lwp) WRITE(numout,*) '~~~~~~~~~~~~~ ' ! ! allocate lim_sbc array IF( lim_sbc_alloc() /= 0 ) CALL ctl_stop( 'STOP', 'lim_sbc_init : unable to allocate standard arrays' ) ! r1_rdtice = 1. / rdt_ice ! soce_0(:,:) = soce ! constant SSS and ice salinity used in levitating sea-ice case sice_0(:,:) = sice ! IF( cp_cfg == "orca" ) THEN ! decrease ocean & ice reference salinities in the Baltic sea WHERE( 14._wp <= glamt(:,:) .AND. glamt(:,:) <= 32._wp .AND. & & 54._wp <= gphit(:,:) .AND. gphit(:,:) <= 66._wp ) soce_0(:,:) = 4._wp sice_0(:,:) = 2._wp END WHERE ENDIF ! END SUBROUTINE lim_sbc_init #else !!---------------------------------------------------------------------- !! Default option : Dummy module NO LIM 3.0 sea-ice model !!---------------------------------------------------------------------- CONTAINS SUBROUTINE lim_sbc ! Dummy routine END SUBROUTINE lim_sbc #endif !!====================================================================== END MODULE limsbc