MODULE limdyn !!====================================================================== !! *** MODULE limdyn *** !! Sea-Ice dynamics : !!====================================================================== #if defined key_ice_lim !!---------------------------------------------------------------------- !! 'key_ice_lim' : LIM sea-ice model !!---------------------------------------------------------------------- !! lim_dyn : computes ice velocities !! lim_dyn_init : initialization and namelist read !!---------------------------------------------------------------------- !! * Modules used USE phycst USE in_out_manager ! I/O manager USE dom_ice USE dom_oce ! ocean space and time domain USE ice USE ice_oce USE iceini USE limistate USE limrhg ! ice rheology USE lbclnk USE lib_mpp USE prtctl ! Print control IMPLICIT NONE PRIVATE !! * Accessibility PUBLIC lim_dyn ! routine called by ice_step !! * Module variables REAL(wp) :: rone = 1.e0 ! constant value !!---------------------------------------------------------------------- !! LIM 2.0, UCL-LOCEAN-IPSL (2005) !! $Header$ !! This software is governed by the CeCILL licence see modipsl/doc/NEMO_CeCILL.txt !!---------------------------------------------------------------------- CONTAINS SUBROUTINE lim_dyn !!------------------------------------------------------------------- !! *** ROUTINE lim_dyn *** !! !! ** Purpose : compute ice velocity and ocean-ice stress !! !! ** Method : !! !! ** Action : - Initialisation !! - Call of the dynamic routine for each hemisphere !! - computation of the stress at the ocean surface !! - treatment of the case if no ice dynamic !! History : !! 1.0 ! 01-04 (LIM) Original code !! 2.0 ! 02-08 (C. Ethe, G. Madec) F90, mpp !!--------------------------------------------------------------------- !! * Loal variables INTEGER :: ji, jj ! dummy loop indices INTEGER :: i_j1, i_jpj ! Starting/ending j-indices for rheology REAL(wp) :: & ztairx, ztairy, & ! tempory scalars zsang , zmod, & ztglx , ztgly , & zt11, zt12, zt21, zt22 , & zustm, zsfrld, zsfrldm4, & zu_ice, zv_ice, ztair2 REAL(wp),DIMENSION(jpj) :: & zind, & ! i-averaged indicator of sea-ice zmsk ! i-averaged of tmask !!--------------------------------------------------------------------- IF( numit == nstart ) CALL lim_dyn_init ! Initialization (first time-step only) IF ( ln_limdyn ) THEN ! Mean ice and snow thicknesses. hsnm(:,:) = ( 1.0 - frld(:,:) ) * hsnif(:,:) hicm(:,:) = ( 1.0 - frld(:,:) ) * hicif(:,:) u_oce(:,:) = u_io(:,:) * tmu(:,:) v_oce(:,:) = v_io(:,:) * tmu(:,:) ! ! Rheology (ice dynamics) ! ! ======== ! Define the j-limits where ice rheology is computed ! --------------------------------------------------- IF( lk_mpp ) THEN ! mpp: compute over the whole domain i_j1 = 1 i_jpj = jpj IF(ln_ctl) THEN CALL prt_ctl_info('lim_dyn : i_j1 = ', ivar1=i_j1, clinfo2=' ij_jpj = ', ivar2=i_jpj) ENDIF CALL lim_rhg( i_j1, i_jpj ) ELSE ! optimization of the computational area DO jj = 1, jpj zind(jj) = SUM( frld (:,jj ) ) ! = FLOAT(jpj) if ocean everywhere on a j-line zmsk(jj) = SUM( tmask(:,jj,1) ) ! = 0 if land everywhere on a j-line !!i write(numout,*) narea, 'limdyn' , jj, zind(jj), zmsk(jj) END DO IF( l_jeq ) THEN ! local domain include both hemisphere ! ! Rheology is computed in each hemisphere ! ! only over the ice cover latitude strip ! Northern hemisphere i_j1 = njeq i_jpj = jpj DO WHILE ( i_j1 <= jpj .AND. zind(i_j1) == FLOAT(jpi) .AND. zmsk(i_j1) /=0 ) i_j1 = i_j1 + 1 END DO i_j1 = MAX( 1, i_j1-1 ) IF(ln_ctl) WRITE(numout,*) 'lim_dyn : NH i_j1 = ', i_j1, ' ij_jpj = ', i_jpj CALL lim_rhg( i_j1, i_jpj ) ! Southern hemisphere i_j1 = 1 i_jpj = njeq DO WHILE ( i_jpj >= 1 .AND. zind(i_jpj) == FLOAT(jpi) .AND. zmsk(i_jpj) /=0 ) i_jpj = i_jpj - 1 END DO i_jpj = MIN( jpj, i_jpj+2 ) IF(ln_ctl) WRITE(numout,*) 'lim_dyn : SH i_j1 = ', i_j1, ' ij_jpj = ', i_jpj CALL lim_rhg( i_j1, i_jpj ) ELSE ! local domain extends over one hemisphere only ! ! Rheology is computed only over the ice cover ! ! latitude strip i_j1 = 1 DO WHILE ( i_j1 <= jpj .AND. zind(i_j1) == FLOAT(jpi) .AND. zmsk(i_j1) /=0 ) i_j1 = i_j1 + 1 END DO i_j1 = MAX( 1, i_j1-1 ) i_jpj = jpj DO WHILE ( i_jpj >= 1 .AND. zind(i_jpj) == FLOAT(jpi) .AND. zmsk(i_jpj) /=0 ) i_jpj = i_jpj - 1 END DO i_jpj = MIN( jpj, i_jpj+2) IF(ln_ctl) WRITE(numout,*) 'lim_dyn : one hemisphere: i_j1 = ', i_j1, ' ij_jpj = ', i_jpj CALL lim_rhg( i_j1, i_jpj ) ENDIF ENDIF IF(ln_ctl) THEN CALL prt_ctl(tab2d_1=u_oce , clinfo1=' lim_dyn : u_oce :', tab2d_2=v_oce , clinfo2=' v_oce :') CALL prt_ctl(tab2d_1=u_ice , clinfo1=' lim_dyn : u_ice :', tab2d_2=v_ice , clinfo2=' v_ice :') ENDIF ! ! Ice-Ocean stress ! ! ================ DO jj = 2, jpjm1 zsang = SIGN(1.e0, gphif(1,jj-1) ) * sangvg DO ji = 2, jpim1 ! computation of wind stress over ocean in X and Y direction #if defined key_coupled && defined key_lim_cp1 ztairx = frld(ji-1,jj ) * gtaux(ji-1,jj ) + frld(ji,jj ) * gtaux(ji,jj ) & & + frld(ji-1,jj-1) * gtaux(ji-1,jj-1) + frld(ji,jj-1) * gtaux(ji,jj-1) ztairy = frld(ji-1,jj ) * gtauy(ji-1,jj ) + frld(ji,jj ) * gtauy(ji,jj ) & & + frld(ji-1,jj-1) * gtauy(ji-1,jj-1) + frld(ji,jj-1) * gtauy(ji,jj-1) #else zsfrld = frld(ji,jj) + frld(ji-1,jj) + frld(ji-1,jj-1) + frld(ji,jj-1) ztairx = zsfrld * gtaux(ji,jj) ztairy = zsfrld * gtauy(ji,jj) #endif zsfrldm4 = 4 - frld(ji,jj) - frld(ji-1,jj) - frld(ji-1,jj-1) - frld(ji,jj-1) zu_ice = u_ice(ji,jj) - u_oce(ji,jj) zv_ice = v_ice(ji,jj) - v_oce(ji,jj) zmod = SQRT( zu_ice * zu_ice + zv_ice * zv_ice ) ztglx = zsfrldm4 * rhoco * zmod * ( cangvg * zu_ice - zsang * zv_ice ) ztgly = zsfrldm4 * rhoco * zmod * ( cangvg * zv_ice + zsang * zu_ice ) tio_u(ji,jj) = - ( ztairx + 1.0 * ztglx ) / ( 4 * rau0 ) tio_v(ji,jj) = - ( ztairy + 1.0 * ztgly ) / ( 4 * rau0 ) END DO END DO ! computation of friction velocity DO jj = 2, jpjm1 DO ji = 2, jpim1 zu_ice = u_ice(ji-1,jj-1) - u_oce(ji-1,jj-1) zv_ice = v_ice(ji-1,jj-1) - v_oce(ji-1,jj-1) zt11 = rhoco * ( zu_ice * zu_ice + zv_ice * zv_ice ) zu_ice = u_ice(ji-1,jj) - u_oce(ji-1,jj) zv_ice = v_ice(ji-1,jj) - v_oce(ji-1,jj) zt12 = rhoco * ( zu_ice * zu_ice + zv_ice * zv_ice ) zu_ice = u_ice(ji,jj-1) - u_oce(ji,jj-1) zv_ice = v_ice(ji,jj-1) - v_oce(ji,jj-1) zt21 = rhoco * ( zu_ice * zu_ice + zv_ice * zv_ice ) zu_ice = u_ice(ji,jj) - u_oce(ji,jj) zv_ice = v_ice(ji,jj) - v_oce(ji,jj) zt22 = rhoco * ( zu_ice * zu_ice + zv_ice * zv_ice ) ztair2 = gtaux(ji,jj) * gtaux(ji,jj) + gtauy(ji,jj) * gtauy(ji,jj) zustm = ( 1 - frld(ji,jj) ) * 0.25 * ( zt11 + zt12 + zt21 + zt22 ) & & + frld(ji,jj) * SQRT( ztair2 ) ust2s(ji,jj) = ( zustm / rau0 ) * ( rone + sdvt(ji,jj) ) * tms(ji,jj) END DO END DO ELSE ! no ice dynamics : transmit directly the atmospheric stress to the ocean DO jj = 2, jpjm1 DO ji = 2, jpim1 #if defined key_coupled && defined key_lim_cp1 tio_u(ji,jj) = - ( gtaux(ji ,jj ) + gtaux(ji-1,jj ) & & + gtaux(ji-1,jj-1) + gtaux(ji ,jj-1) ) / ( 4 * rau0 ) tio_v(ji,jj) = - ( gtauy(ji ,jj ) + gtauy(ji-1,jj ) & & + gtauy(ji-1,jj-1) + gtauy(ji ,jj-1) ) / ( 4 * rau0 ) #else tio_u(ji,jj) = - gtaux(ji,jj) / rau0 tio_v(ji,jj) = - gtauy(ji,jj) / rau0 #endif ztair2 = gtaux(ji,jj) * gtaux(ji,jj) + gtauy(ji,jj) * gtauy(ji,jj) zustm = SQRT( ztair2 ) ust2s(ji,jj) = ( zustm / rau0 ) * ( rone + sdvt(ji,jj) ) * tms(ji,jj) END DO END DO ENDIF CALL lbc_lnk( ust2s, 'T', 1. ) ! T-point CALL lbc_lnk( tio_u, 'I', -1. ) ! I-point (i.e. ice U-V point) CALL lbc_lnk( tio_v, 'I', -1. ) ! I-point (i.e. ice U-V point) IF(ln_ctl) THEN CALL prt_ctl(tab2d_1=tio_u , clinfo1=' lim_dyn : tio_u :', tab2d_2=tio_v , clinfo2=' tio_v :') CALL prt_ctl(tab2d_1=ust2s , clinfo1=' lim_dyn : ust2s :') ENDIF END SUBROUTINE lim_dyn SUBROUTINE lim_dyn_init !!------------------------------------------------------------------- !! *** ROUTINE lim_dyn_init *** !! !! ** Purpose : Physical constants and parameters linked to the ice !! dynamics !! !! ** Method : Read the namicedyn namelist and check the ice-dynamic !! parameter values called at the first timestep (nit000) !! !! ** input : Namelist namicedyn !! !! history : !! 8.5 ! 03-08 (C. Ethe) original code !!------------------------------------------------------------------- NAMELIST/namicedyn/ epsd, alpha, & & dm, nbiter, nbitdr, om, resl, cw, angvg, pstar, & & c_rhg, etamn, creepl, ecc, ahi0 !!------------------------------------------------------------------- ! Define the initial parameters ! ------------------------- ! Read Namelist namicedyn REWIND ( numnam_ice ) READ ( numnam_ice , namicedyn ) IF(lwp) THEN WRITE(numout,*) WRITE(numout,*) 'lim_dyn_init : ice parameters for ice dynamics ' WRITE(numout,*) '~~~~~~~~~~~~' WRITE(numout,*) ' tolerance parameter epsd = ', epsd WRITE(numout,*) ' coefficient for semi-implicit coriolis alpha = ', alpha WRITE(numout,*) ' diffusion constant for dynamics dm = ', dm WRITE(numout,*) ' number of sub-time steps for relaxation nbiter = ', nbiter WRITE(numout,*) ' maximum number of iterations for relaxation nbitdr = ', nbitdr WRITE(numout,*) ' relaxation constant om = ', om WRITE(numout,*) ' maximum value for the residual of relaxation resl = ', resl WRITE(numout,*) ' drag coefficient for oceanic stress cw = ', cw WRITE(numout,*) ' turning angle for oceanic stress angvg = ', angvg WRITE(numout,*) ' first bulk-rheology parameter pstar = ', pstar WRITE(numout,*) ' second bulk-rhelogy parameter c_rhg = ', c_rhg WRITE(numout,*) ' minimun value for viscosity etamn = ', etamn WRITE(numout,*) ' creep limit creepl = ', creepl WRITE(numout,*) ' eccentricity of the elliptical yield curve ecc = ', ecc WRITE(numout,*) ' horizontal diffusivity coeff. for sea-ice ahi0 = ', ahi0 ENDIF usecc2 = 1.0 / ( ecc * ecc ) rhoco = rau0 * cw angvg = angvg * rad sangvg = SIN( angvg ) cangvg = COS( angvg ) pstarh = pstar / 2.0 ! Diffusion coefficients. ahiu(:,:) = ahi0 * umask(:,:,1) ahiv(:,:) = ahi0 * vmask(:,:,1) END SUBROUTINE lim_dyn_init #else !!---------------------------------------------------------------------- !! Default option Empty module NO LIM sea-ice model !!---------------------------------------------------------------------- CONTAINS SUBROUTINE lim_dyn ! Empty routine END SUBROUTINE lim_dyn #endif !!====================================================================== END MODULE limdyn