| 1 | MODULE limdyn |
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| 2 | !!====================================================================== |
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| 3 | !! *** MODULE limdyn *** |
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| 4 | !! Sea-Ice dynamics : |
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| 5 | !!====================================================================== |
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| 6 | !! History : 1.0 ! 01-04 (LIM) Original code |
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| 7 | !! 2.0 ! 02-08 (C. Ethe, G. Madec) F90, mpp |
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| 8 | !! 2.0 ! 03-08 (C. Ethe) add lim_dyn_init |
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| 9 | !! 2.0 ! 06-07 (G. Madec) Surface module |
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| 10 | !!--------------------------------------------------------------------- |
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| 11 | #if defined key_ice_lim |
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| 12 | !!---------------------------------------------------------------------- |
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| 13 | !! 'key_ice_lim' : LIM sea-ice model |
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| 14 | !!---------------------------------------------------------------------- |
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| 15 | !! lim_dyn : computes ice velocities |
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| 16 | !! lim_dyn_init : initialization and namelist read |
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| 17 | !!---------------------------------------------------------------------- |
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| 18 | USE dom_oce ! ocean space and time domain |
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| 19 | USE sbc_oce ! |
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| 20 | USE phycst ! |
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| 21 | USE ice ! |
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| 22 | USE ice_oce ! |
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| 23 | USE dom_ice ! |
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| 24 | USE iceini ! |
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| 25 | USE limistate ! |
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| 26 | USE limrhg ! ice rheology |
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| 27 | |
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| 28 | USE lbclnk ! |
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| 29 | USE lib_mpp ! |
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| 30 | USE in_out_manager ! I/O manager |
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| 31 | USE prtctl ! Print control |
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| 32 | |
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| 33 | IMPLICIT NONE |
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| 34 | PRIVATE |
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| 35 | |
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| 36 | PUBLIC lim_dyn ! routine called by ice_step |
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| 37 | |
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| 38 | REAL(wp) :: rone = 1.e0 ! constant value |
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| 39 | |
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| 40 | # include "vectopt_loop_substitute.h90" |
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| 41 | !!---------------------------------------------------------------------- |
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| 42 | !! LIM 2.0, UCL-LOCEAN-IPSL (2006) |
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| 43 | !! $Id$ |
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| 44 | !! Software governed by the CeCILL licence (modipsl/doc/NEMO_CeCILL.txt) |
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| 45 | !!---------------------------------------------------------------------- |
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| 46 | |
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| 47 | CONTAINS |
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| 48 | |
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| 49 | SUBROUTINE lim_dyn( kt ) |
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| 50 | !!------------------------------------------------------------------- |
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| 51 | !! *** ROUTINE lim_dyn *** |
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| 52 | !! |
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| 53 | !! ** Purpose : compute ice velocity and ocean-ice stress |
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| 54 | !! |
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| 55 | !! ** Method : |
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| 56 | !! |
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| 57 | !! ** Action : - Initialisation |
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| 58 | !! - Call of the dynamic routine for each hemisphere |
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| 59 | !! - computation of the stress at the ocean surface |
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| 60 | !! - treatment of the case if no ice dynamic |
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| 61 | !!--------------------------------------------------------------------- |
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| 62 | INTEGER, INTENT(in) :: kt ! number of iteration |
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| 63 | !! |
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| 64 | INTEGER :: ji, jj ! dummy loop indices |
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| 65 | INTEGER :: i_j1, i_jpj ! Starting/ending j-indices for rheology |
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| 66 | REAL(wp) :: zcoef ! temporary scalar |
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| 67 | REAL(wp), DIMENSION(jpj) :: zind ! i-averaged indicator of sea-ice |
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| 68 | REAL(wp), DIMENSION(jpj) :: zmsk ! i-averaged of tmask |
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| 69 | REAL(wp), DIMENSION(jpi,jpj) :: zu_io, zv_io ! ice-ocean velocity |
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| 70 | !!$ INTEGER :: ji, jj ! dummy loop indices |
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| 71 | !!$ INTEGER :: i_j1, i_jpj ! Starting/ending j-indices for rheology |
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| 72 | !!$ REAL(wp) :: & |
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| 73 | !!$ ztairx, ztairy, & ! tempory scalars |
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| 74 | !!$ zsang , zrhomod, & |
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| 75 | !!$ ztglx , ztgly , & |
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| 76 | !!$ zt11, zt12, zt21, zt22 , & |
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| 77 | !!$ zustm, zsfrld, zsfrldm4, & |
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| 78 | !!$ zu_ice, zv_ice, ztair2 |
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| 79 | !!$ REAL(wp),DIMENSION(jpi,jpj) :: zmod |
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| 80 | !!$ REAL(wp),DIMENSION(jpj) :: & |
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| 81 | !!$ zind, & ! i-averaged indicator of sea-ice |
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| 82 | !!$ zmsk ! i-averaged of tmask |
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| 83 | !!--------------------------------------------------------------------- |
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| 84 | |
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| 85 | IF( kt == nit000 ) CALL lim_dyn_init ! Initialization (first time-step only) |
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| 86 | |
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| 87 | IF( ln_limdyn ) THEN |
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| 88 | |
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| 89 | ! Mean ice and snow thicknesses. |
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| 90 | hsnm(:,:) = ( 1.0 - frld(:,:) ) * hsnif(:,:) |
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| 91 | hicm(:,:) = ( 1.0 - frld(:,:) ) * hicif(:,:) |
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| 92 | |
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| 93 | ! ! Rheology (ice dynamics) |
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| 94 | ! ! ======== |
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| 95 | |
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| 96 | ! Define the j-limits where ice rheology is computed |
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| 97 | ! --------------------------------------------------- |
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| 98 | |
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| 99 | IF( lk_mpp .OR. nbit_cmp == 1 ) THEN ! mpp: compute over the whole domain |
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| 100 | i_j1 = 1 |
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| 101 | i_jpj = jpj |
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| 102 | IF(ln_ctl) CALL prt_ctl_info( 'lim_dyn : i_j1 = ', ivar1=i_j1, clinfo2=' ij_jpj = ', ivar2=i_jpj ) |
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| 103 | CALL lim_rhg( i_j1, i_jpj ) |
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| 104 | |
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| 105 | ELSE ! optimization of the computational area |
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| 106 | |
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| 107 | DO jj = 1, jpj |
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| 108 | zind(jj) = SUM( frld (:,jj ) ) ! = FLOAT(jpj) if ocean everywhere on a j-line |
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| 109 | zmsk(jj) = SUM( tmask(:,jj,1) ) ! = 0 if land everywhere on a j-line |
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| 110 | END DO |
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| 111 | |
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| 112 | IF( l_jeq ) THEN ! local domain include both hemisphere |
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| 113 | ! ! Rheology is computed in each hemisphere |
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| 114 | ! ! only over the ice cover latitude strip |
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| 115 | ! Northern hemisphere |
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| 116 | i_j1 = njeq |
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| 117 | i_jpj = jpj |
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| 118 | DO WHILE ( i_j1 <= jpj .AND. zind(i_j1) == FLOAT(jpi) .AND. zmsk(i_j1) /=0 ) |
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| 119 | i_j1 = i_j1 + 1 |
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| 120 | END DO |
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| 121 | i_j1 = MAX( 1, i_j1-1 ) |
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| 122 | IF(ln_ctl) WRITE(numout,*) 'lim_dyn : NH i_j1 = ', i_j1, ' ij_jpj = ', i_jpj |
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| 123 | |
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| 124 | CALL lim_rhg( i_j1, i_jpj ) |
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| 125 | |
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| 126 | ! Southern hemisphere |
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| 127 | i_j1 = 1 |
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| 128 | i_jpj = njeq |
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| 129 | DO WHILE ( i_jpj >= 1 .AND. zind(i_jpj) == FLOAT(jpi) .AND. zmsk(i_jpj) /=0 ) |
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| 130 | i_jpj = i_jpj - 1 |
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| 131 | END DO |
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| 132 | i_jpj = MIN( jpj, i_jpj+2 ) |
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| 133 | IF(ln_ctl) WRITE(numout,*) 'lim_dyn : SH i_j1 = ', i_j1, ' ij_jpj = ', i_jpj |
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| 134 | |
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| 135 | CALL lim_rhg( i_j1, i_jpj ) |
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| 136 | |
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| 137 | ELSE ! local domain extends over one hemisphere only |
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| 138 | ! ! Rheology is computed only over the ice cover |
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| 139 | ! ! latitude strip |
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| 140 | i_j1 = 1 |
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| 141 | DO WHILE ( i_j1 <= jpj .AND. zind(i_j1) == FLOAT(jpi) .AND. zmsk(i_j1) /=0 ) |
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| 142 | i_j1 = i_j1 + 1 |
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| 143 | END DO |
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| 144 | i_j1 = MAX( 1, i_j1-1 ) |
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| 145 | |
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| 146 | i_jpj = jpj |
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| 147 | DO WHILE ( i_jpj >= 1 .AND. zind(i_jpj) == FLOAT(jpi) .AND. zmsk(i_jpj) /=0 ) |
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| 148 | i_jpj = i_jpj - 1 |
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| 149 | END DO |
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| 150 | i_jpj = MIN( jpj, i_jpj+2) |
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| 151 | |
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| 152 | IF(ln_ctl) WRITE(numout,*) 'lim_dyn : one hemisphere: i_j1 = ', i_j1, ' ij_jpj = ', i_jpj |
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| 153 | |
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| 154 | CALL lim_rhg( i_j1, i_jpj ) |
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| 155 | |
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| 156 | ENDIF |
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| 157 | |
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| 158 | ENDIF |
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| 159 | |
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| 160 | IF(ln_ctl) CALL prt_ctl(tab2d_1=ui_ice , clinfo1=' lim_dyn : ui_ice :', tab2d_2=vi_ice , clinfo2=' vi_ice :') |
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| 161 | |
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| 162 | !!$ ! ! Ice-Ocean stress |
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| 163 | !!$ ! ! ================ |
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| 164 | !!$ DO jj = 1, jpj |
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| 165 | !!$ DO ji = 1, jpi |
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| 166 | !!$!! zsang = SIGN(1.e0, gphif(ji-1,jj-1) ) * sangvg ! do the full loop and avoid lbc_lnk |
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| 167 | !!$ zsang = SIGN(1.e0, gphif(ji,jj) ) * sangvg |
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| 168 | !!$ zu_ice = u_ice(ji,jj) - u_io(ji,jj) |
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| 169 | !!$ zv_ice = v_ice(ji,jj) - v_io(ji,jj) |
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| 170 | !!$ zrhomod = zu_ice * zu_ice + zv_ice * zv_ice |
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| 171 | !!$ zmod (ji,jj) = zrhomod |
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| 172 | !!$ zrhomod = rhoco * SQRT( zrhomod ) |
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| 173 | !!$ ftaux(ji,jj) = zrhomod * ( cangvg * zu_ice - zsang * zv_ice ) |
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| 174 | !!$ ftauy(ji,jj) = zrhomod * ( cangvg * zv_ice + zsang * zu_ice ) |
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| 175 | !!$ END DO |
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| 176 | !!$ END DO |
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| 177 | |
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| 178 | ! computation of friction velocity |
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| 179 | ! -------------------------------- |
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| 180 | ! ice-ocean velocity at U & V-points (ui_ice vi_ice at I-point ; ssu_m, ssv_m at U- & V-points) |
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| 181 | |
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| 182 | DO jj = 1, jpjm1 |
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| 183 | DO ji = 1, fs_jpim1 ! vector opt. |
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| 184 | zu_io(ji,jj) = 0.5 * ( ui_ice(ji+1,jj+1) + ui_ice(ji+1,jj ) ) - ssu_m(ji,jj) |
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| 185 | zv_io(ji,jj) = 0.5 * ( vi_ice(ji+1,jj+1) + vi_ice(ji ,jj+1) ) - ssv_m(ji,jj) |
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| 186 | END DO |
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| 187 | END DO |
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| 188 | ! frictional velocity at T-point |
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| 189 | DO jj = 2, jpjm1 |
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| 190 | DO ji = fs_2, fs_jpim1 ! vector opt. |
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| 191 | ust2s(ji,jj) = 0.5 * cw & |
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| 192 | & * ( zu_io(ji,jj) * zu_io(ji,jj) + zu_io(ji-1,jj) * zu_io(ji-1,jj) & |
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| 193 | & + zv_io(ji,jj) * zv_io(ji,jj) + zv_io(ji,jj-1) * zv_io(ji,jj-1) ) * tms(ji,jj) |
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| 194 | END DO |
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| 195 | END DO |
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| 196 | !!$ DO jj = 2, jpjm1 |
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| 197 | !!$ DO ji = fs_2, fs_jpim1 ! vector opt. |
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| 198 | !!$ ust2s(ji,jj) = 0.25 * cw * ( zmod(ji,jj+1) + zmod(ji+1,jj+1) + & |
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| 199 | !!$ & zmod(ji,jj ) + zmod(ji+1,jj ) ) * tms(ji,jj) |
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| 200 | !!$ END DO |
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| 201 | !!$ END DO |
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| 202 | ! |
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| 203 | ELSE ! no ice dynamics : transmit directly the atmospheric stress to the ocean |
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| 204 | ! |
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| 205 | zcoef = SQRT( 0.5 ) / rau0 |
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| 206 | DO jj = 2, jpjm1 |
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| 207 | DO ji = fs_2, fs_jpim1 ! vector opt. |
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| 208 | ust2s(ji,jj) = zcoef * tms(ji,jj) * SQRT( utau(ji,jj) * utau(ji,jj) + utau(ji-1,jj) * utau(ji-1,jj) & |
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| 209 | & + vtau(ji,jj) * vtau(ji,jj) + vtau(ji,jj-1) * vtau(ji,jj-1) ) |
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| 210 | END DO |
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| 211 | END DO |
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| 212 | ! |
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| 213 | ENDIF |
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| 214 | |
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| 215 | CALL lbc_lnk( ust2s, 'T', 1. ) ! T-point |
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| 216 | |
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| 217 | IF(ln_ctl) CALL prt_ctl(tab2d_1=ust2s , clinfo1=' lim_dyn : ust2s :') |
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| 218 | |
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| 219 | END SUBROUTINE lim_dyn |
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| 220 | |
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| 221 | |
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| 222 | SUBROUTINE lim_dyn_init |
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| 223 | !!------------------------------------------------------------------- |
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| 224 | !! *** ROUTINE lim_dyn_init *** |
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| 225 | !! |
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| 226 | !! ** Purpose : Physical constants and parameters linked to the ice |
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| 227 | !! dynamics |
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| 228 | !! |
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| 229 | !! ** Method : Read the namicedyn namelist and check the ice-dynamic |
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| 230 | !! parameter values |
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| 231 | !! |
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| 232 | !! ** input : Namelist namicedyn |
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| 233 | !!------------------------------------------------------------------- |
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| 234 | NAMELIST/namicedyn/ epsd, alpha, & |
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| 235 | & dm, nbiter, nbitdr, om, resl, cw, angvg, pstar, & |
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| 236 | & c_rhg, etamn, creepl, ecc, ahi0 |
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| 237 | !!------------------------------------------------------------------- |
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| 238 | |
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| 239 | REWIND ( numnam_ice ) ! Read Namelist namicedyn |
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| 240 | READ ( numnam_ice , namicedyn ) |
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| 241 | |
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| 242 | IF(lwp) THEN ! Control print |
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| 243 | WRITE(numout,*) |
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| 244 | WRITE(numout,*) 'lim_dyn_init : ice parameters for ice dynamics ' |
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| 245 | WRITE(numout,*) '~~~~~~~~~~~~' |
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| 246 | WRITE(numout,*) ' tolerance parameter epsd = ', epsd |
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| 247 | WRITE(numout,*) ' coefficient for semi-implicit coriolis alpha = ', alpha |
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| 248 | WRITE(numout,*) ' diffusion constant for dynamics dm = ', dm |
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| 249 | WRITE(numout,*) ' number of sub-time steps for relaxation nbiter = ', nbiter |
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| 250 | WRITE(numout,*) ' maximum number of iterations for relaxation nbitdr = ', nbitdr |
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| 251 | WRITE(numout,*) ' relaxation constant om = ', om |
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| 252 | WRITE(numout,*) ' maximum value for the residual of relaxation resl = ', resl |
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| 253 | WRITE(numout,*) ' drag coefficient for oceanic stress cw = ', cw |
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| 254 | WRITE(numout,*) ' turning angle for oceanic stress angvg = ', angvg, ' degrees' |
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| 255 | WRITE(numout,*) ' first bulk-rheology parameter pstar = ', pstar |
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| 256 | WRITE(numout,*) ' second bulk-rhelogy parameter c_rhg = ', c_rhg |
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| 257 | WRITE(numout,*) ' minimun value for viscosity etamn = ', etamn |
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| 258 | WRITE(numout,*) ' creep limit creepl = ', creepl |
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| 259 | WRITE(numout,*) ' eccentricity of the elliptical yield curve ecc = ', ecc |
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| 260 | WRITE(numout,*) ' horizontal diffusivity coeff. for sea-ice ahi0 = ', ahi0 |
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| 261 | ENDIF |
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| 262 | |
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| 263 | usecc2 = 1.0 / ( ecc * ecc ) |
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| 264 | rhoco = rau0 * cw |
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| 265 | angvg = angvg * rad ! convert angvg from degree to radian |
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| 266 | sangvg = SIN( angvg ) |
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| 267 | cangvg = COS( angvg ) |
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| 268 | pstarh = pstar / 2.0 |
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| 269 | ! |
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| 270 | ahiu(:,:) = ahi0 * umask(:,:,1) ! Ice eddy Diffusivity coefficients. |
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| 271 | ahiv(:,:) = ahi0 * vmask(:,:,1) |
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| 272 | ! |
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| 273 | END SUBROUTINE lim_dyn_init |
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| 274 | |
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| 275 | #else |
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| 276 | !!---------------------------------------------------------------------- |
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| 277 | !! Default option Empty module NO LIM sea-ice model |
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| 278 | !!---------------------------------------------------------------------- |
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| 279 | CONTAINS |
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| 280 | SUBROUTINE lim_dyn ! Empty routine |
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| 281 | END SUBROUTINE lim_dyn |
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| 282 | #endif |
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| 283 | |
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| 284 | !!====================================================================== |
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| 285 | END MODULE limdyn |
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