MODULE limhdf !!====================================================================== !! *** MODULE limhdf *** !! LIM ice model : horizontal diffusion of sea-ice quantities !!====================================================================== !! History : LIM ! 2000-01 (LIM) Original code !! - ! 2001-05 (G. Madec, R. Hordoir) opa norm !! 1.0 ! 2002-08 (C. Ethe) F90, free form !!---------------------------------------------------------------------- #if defined key_lim3 !!---------------------------------------------------------------------- !! 'key_lim3' LIM3 sea-ice model !!---------------------------------------------------------------------- !! lim_hdf : diffusion trend on sea-ice variable !!---------------------------------------------------------------------- USE dom_oce ! ocean domain USE ice ! LIM-3: ice variables USE lbclnk ! lateral boundary condition - MPP exchanges USE lib_mpp ! MPP library USE wrk_nemo ! work arrays USE prtctl ! Print control USE in_out_manager ! I/O manager USE lib_fortran ! Fortran utilities (allows no signed zero when 'key_nosignedzero' defined) IMPLICIT NONE PRIVATE PUBLIC lim_hdf ! called by lim_tra LOGICAL :: linit = .TRUE. ! initialization flag (set to flase after the 1st call) REAL(wp) :: epsi04 = 1.e-04 ! constant REAL(wp), ALLOCATABLE, SAVE, DIMENSION(:,:) :: efact ! metric coefficient !! * Substitution # include "vectopt_loop_substitute.h90" !!---------------------------------------------------------------------- !! NEMO/LIM3 4.0 , UCL - NEMO Consortium (2010) !! $Id$ !! Software governed by the CeCILL licence (NEMOGCM/NEMO_CeCILL.txt) !!---------------------------------------------------------------------- CONTAINS SUBROUTINE lim_hdf( ptab ) !!------------------------------------------------------------------- !! *** ROUTINE lim_hdf *** !! !! ** purpose : Compute and add the diffusive trend on sea-ice variables !! !! ** method : Second order diffusive operator evaluated using a !! Cranck-Nicholson time Scheme. !! !! ** Action : update ptab with the diffusive contribution !!------------------------------------------------------------------- REAL(wp), DIMENSION(jpi,jpj), INTENT( inout ) :: ptab ! Field on which the diffusion is applied ! INTEGER :: ji, jj ! dummy loop indices INTEGER :: its, iter, ierr ! local integers REAL(wp) :: zalfa, zrlxint, zconv ! local scalars REAL(wp), POINTER, DIMENSION(:,:) :: zrlx, zflu, zflv, zdiv0, zdiv, ztab0 CHARACTER(lc) :: charout ! local character !!------------------------------------------------------------------- CALL wrk_alloc( jpi, jpj, zrlx, zflu, zflv, zdiv0, zdiv, ztab0 ) ! !== Initialisation ==! ! IF( linit ) THEN ! Metric coefficient (compute at the first call and saved in efact) ALLOCATE( efact(jpi,jpj) , STAT=ierr ) IF( lk_mpp ) CALL mpp_sum( ierr ) IF( ierr /= 0 ) CALL ctl_stop( 'STOP', 'lim_hdf : unable to allocate arrays' ) DO jj = 2, jpjm1 DO ji = fs_2 , fs_jpim1 ! vector opt. efact(ji,jj) = ( e2u(ji,jj) + e2u(ji-1,jj) + e1v(ji,jj) + e1v(ji,jj-1) ) / ( e1t(ji,jj) * e2t(ji,jj) ) END DO END DO linit = .FALSE. ENDIF ! ! Time integration parameters zalfa = 0.5_wp ! =1.0/0.5/0.0 = implicit/Cranck-Nicholson/explicit its = 100 ! Maximum number of iteration ! ztab0(:, : ) = ptab(:,:) ! Arrays initialization zdiv0(:, 1 ) = 0._wp zdiv0(:,jpj) = 0._wp IF( .NOT.lk_vopt_loop ) THEN zflu (jpi,:) = 0._wp zflv (jpi,:) = 0._wp zdiv0(1, :) = 0._wp zdiv0(jpi,:) = 0._wp ENDIF zconv = 1._wp !== horizontal diffusion using a Crant-Nicholson scheme ==! iter = 0 ! DO WHILE( zconv > ( 2._wp * epsi04 ) .AND. iter <= its ) ! Sub-time step loop ! iter = iter + 1 ! incrementation of the sub-time step number ! DO jj = 1, jpjm1 ! diffusive fluxes in U- and V- direction DO ji = 1 , fs_jpim1 ! vector opt. zflu(ji,jj) = pahu(ji,jj) * e2u(ji,jj) / e1u(ji,jj) * ( ptab(ji+1,jj) - ptab(ji,jj) ) zflv(ji,jj) = pahv(ji,jj) * e1v(ji,jj) / e2v(ji,jj) * ( ptab(ji,jj+1) - ptab(ji,jj) ) END DO END DO ! DO jj= 2, jpjm1 ! diffusive trend : divergence of the fluxes DO ji = fs_2 , fs_jpim1 ! vector opt. zdiv (ji,jj) = ( zflu(ji,jj) - zflu(ji-1,jj ) & & + zflv(ji,jj) - zflv(ji ,jj-1) ) / ( e1t (ji,jj) * e2t (ji,jj) ) END DO END DO ! IF( iter == 1 ) zdiv0(:,:) = zdiv(:,:) ! save the 1st evaluation of the diffusive trend in zdiv0 ! DO jj = 2, jpjm1 ! iterative evaluation DO ji = fs_2 , fs_jpim1 ! vector opt. zrlxint = ( ztab0(ji,jj) & & + rdt_ice * ( zalfa * ( zdiv(ji,jj) + efact(ji,jj) * ptab(ji,jj) ) & & + ( 1.0 - zalfa ) * zdiv0(ji,jj) ) ) & & / ( 1.0 + zalfa * rdt_ice * efact(ji,jj) ) zrlx(ji,jj) = ptab(ji,jj) + om * ( zrlxint - ptab(ji,jj) ) END DO END DO CALL lbc_lnk( zrlx, 'T', 1. ) ! lateral boundary condition ! zconv = 0._wp ! convergence test DO jj = 2, jpjm1 DO ji = fs_2, fs_jpim1 zconv = MAX( zconv, ABS( zrlx(ji,jj) - ptab(ji,jj) ) ) END DO END DO IF( lk_mpp ) CALL mpp_max( zconv ) ! max over the global domain ! ptab(:,:) = zrlx(:,:) ! END DO ! end of sub-time step loop ! ----------------------- !!! final step (clem) !!! DO jj = 1, jpjm1 ! diffusive fluxes in U- and V- direction DO ji = 1 , fs_jpim1 ! vector opt. zflu(ji,jj) = pahu(ji,jj) * e2u(ji,jj) / e1u(ji,jj) * ( ptab(ji+1,jj) - ptab(ji,jj) ) zflv(ji,jj) = pahv(ji,jj) * e1v(ji,jj) / e2v(ji,jj) * ( ptab(ji,jj+1) - ptab(ji,jj) ) END DO END DO ! DO jj= 2, jpjm1 ! diffusive trend : divergence of the fluxes DO ji = fs_2 , fs_jpim1 ! vector opt. zdiv (ji,jj) = ( zflu(ji,jj) - zflu(ji-1,jj ) & & + zflv(ji,jj) - zflv(ji ,jj-1) ) / ( e1t (ji,jj) * e2t (ji,jj) ) ptab(ji,jj) = ztab0(ji,jj) + 0.5 * ( zdiv(ji,jj) + zdiv0(ji,jj) ) END DO END DO CALL lbc_lnk( ptab, 'T', 1. ) ! lateral boundary condition !!! final step (clem) !!! ! ----------------------- IF(ln_ctl) THEN zrlx(:,:) = ptab(:,:) - ztab0(:,:) WRITE(charout,FMT="(' lim_hdf : zconv =',D23.16, ' iter =',I4,2X)") zconv, iter CALL prt_ctl( tab2d_1=zrlx, clinfo1=charout ) ENDIF ! CALL wrk_dealloc( jpi, jpj, zrlx, zflu, zflv, zdiv0, zdiv, ztab0 ) ! END SUBROUTINE lim_hdf #else !!---------------------------------------------------------------------- !! Default option Dummy module NO LIM sea-ice model !!---------------------------------------------------------------------- CONTAINS SUBROUTINE lim_hdf ! Empty routine END SUBROUTINE lim_hdf #endif !!====================================================================== END MODULE limhdf