| 1 | MODULE icethd_do |
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| 2 | !!====================================================================== |
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| 3 | !! *** MODULE icethd_do *** |
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| 4 | !! sea-ice: sea ice growth in the leads (open water) |
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| 5 | !!====================================================================== |
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| 6 | !! History : ! 2005-12 (M. Vancoppenolle) Original code |
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| 7 | !! 4.0 ! 2018 (many people) SI3 [aka Sea Ice cube] |
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| 8 | !!---------------------------------------------------------------------- |
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| 9 | #if defined key_si3 |
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| 10 | !!---------------------------------------------------------------------- |
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| 11 | !! 'key_si3' SI3 sea-ice model |
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| 12 | !!---------------------------------------------------------------------- |
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| 13 | !! ice_thd_do : ice growth in open water (=lateral accretion of ice) |
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| 14 | !! ice_thd_do_init : initialization |
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| 15 | !!---------------------------------------------------------------------- |
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| 16 | USE dom_oce ! ocean space and time domain |
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| 17 | USE phycst ! physical constants |
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| 18 | USE sbc_oce , ONLY : sss_m |
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| 19 | USE sbc_ice , ONLY : utau_ice, vtau_ice |
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| 20 | USE ice1D ! sea-ice: thermodynamics variables |
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| 21 | USE ice ! sea-ice: variables |
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| 22 | USE icetab ! sea-ice: 2D <==> 1D |
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| 23 | USE icectl ! sea-ice: conservation |
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| 24 | USE icethd_ent ! sea-ice: thermodynamics, enthalpy |
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| 25 | USE icevar ! sea-ice: operations |
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| 26 | USE icethd_sal ! sea-ice: salinity profiles |
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| 27 | ! |
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| 28 | USE in_out_manager ! I/O manager |
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| 29 | USE lib_mpp ! MPP library |
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| 30 | USE lib_fortran ! fortran utilities (glob_sum + no signed zero) |
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| 31 | USE lbclnk ! lateral boundary conditions (or mpp links) |
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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 ice_thd_do ! called by ice_thd |
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| 37 | PUBLIC ice_thd_frazil ! called by ice_thd |
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| 38 | PUBLIC ice_thd_do_init ! called by ice_stp |
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| 39 | |
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| 40 | !! * Substitutions |
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| 41 | # include "do_loop_substitute.h90" |
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| 42 | !!---------------------------------------------------------------------- |
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| 43 | !! NEMO/ICE 4.0 , NEMO Consortium (2018) |
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| 44 | !! $Id$ |
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| 45 | !! Software governed by the CeCILL license (see ./LICENSE) |
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| 46 | !!---------------------------------------------------------------------- |
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| 47 | CONTAINS |
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| 48 | |
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| 49 | SUBROUTINE ice_thd_do |
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| 50 | !!------------------------------------------------------------------- |
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| 51 | !! *** ROUTINE ice_thd_do *** |
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| 52 | !! |
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| 53 | !! ** Purpose : Computation of the evolution of the ice thickness and |
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| 54 | !! concentration as a function of the heat balance in the leads |
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| 55 | !! |
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| 56 | !! ** Method : Ice is formed in the open water when ocean looses heat |
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| 57 | !! (heat budget of open water is negative) following |
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| 58 | !! |
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| 59 | !! (dA/dt)acc = F[ (1-A)/(1-a) ] * [ Bl / (Li*h0) ] |
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| 60 | !! where - h0 is the thickness of ice created in the lead |
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| 61 | !! - a is a minimum fraction for leads |
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| 62 | !! - F is a monotonic non-increasing function defined as: |
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| 63 | !! F(X)=( 1 - X**exld )**(1.0/exld) |
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| 64 | !! - exld is the exponent closure rate (=2 default val.) |
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| 65 | !! |
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| 66 | !! ** Action : - Adjustment of snow and ice thicknesses and heat |
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| 67 | !! content in brine pockets |
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| 68 | !! - Updating ice internal temperature |
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| 69 | !! - Computation of variation of ice volume and mass |
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| 70 | !! - Computation of a_i after lateral accretion and |
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| 71 | !! update h_s_1d, h_i_1d |
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| 72 | !!------------------------------------------------------------------------ |
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| 73 | INTEGER :: ji, jj, jk, jl ! dummy loop indices |
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| 74 | ! |
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| 75 | REAL(wp) :: ztmelts |
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| 76 | REAL(wp) :: zdE |
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| 77 | REAL(wp) :: zQm ! enthalpy exchanged with the ocean (J/m2, >0 towards ocean) |
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| 78 | REAL(wp) :: zEi ! sea ice specific enthalpy (J/kg) |
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| 79 | REAL(wp) :: zEw ! seawater specific enthalpy (J/kg) |
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| 80 | REAL(wp) :: zfmdt ! mass flux x time step (kg/m2, >0 towards ocean) |
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| 81 | ! |
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| 82 | REAL(wp) :: zv_newfra |
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| 83 | ! |
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| 84 | INTEGER , DIMENSION(jpij) :: jcat ! indexes of categories where new ice grows |
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| 85 | REAL(wp), DIMENSION(jpij) :: zswinew ! switch for new ice or not |
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| 86 | ! |
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| 87 | REAL(wp), DIMENSION(jpij) :: zv_newice ! volume of accreted ice |
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| 88 | REAL(wp), DIMENSION(jpij) :: za_newice ! fractional area of accreted ice |
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| 89 | REAL(wp), DIMENSION(jpij) :: zh_newice ! thickness of accreted ice |
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| 90 | REAL(wp), DIMENSION(jpij) :: ze_newice ! heat content of accreted ice |
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| 91 | REAL(wp), DIMENSION(jpij) :: zs_newice ! salinity of accreted ice |
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| 92 | REAL(wp), DIMENSION(jpij) :: zo_newice ! age of accreted ice |
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| 93 | REAL(wp), DIMENSION(jpij) :: zdv_res ! residual volume in case of excessive heat budget |
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| 94 | REAL(wp), DIMENSION(jpij) :: zda_res ! residual area in case of excessive heat budget |
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| 95 | REAL(wp), DIMENSION(jpij) :: zv_frazb ! accretion of frazil ice at the ice bottom |
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| 96 | REAL(wp), DIMENSION(jpij) :: zfraz_frac_1d ! relative ice / frazil velocity (1D vector) |
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| 97 | ! |
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| 98 | REAL(wp), DIMENSION(jpij,jpl) :: zv_b ! old volume of ice in category jl |
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| 99 | REAL(wp), DIMENSION(jpij,jpl) :: za_b ! old area of ice in category jl |
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| 100 | ! |
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| 101 | REAL(wp), DIMENSION(jpij,nlay_i,jpl) :: ze_i_2d !: 1-D version of e_i |
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| 102 | ! |
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| 103 | !!-----------------------------------------------------------------------! |
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| 104 | |
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| 105 | IF( ln_icediachk ) CALL ice_cons_hsm( 0, 'icethd_do', rdiag_v, rdiag_s, rdiag_t, rdiag_fv, rdiag_fs, rdiag_ft ) |
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| 106 | IF( ln_icediachk ) CALL ice_cons2D ( 0, 'icethd_do', diag_v, diag_s, diag_t, diag_fv, diag_fs, diag_ft ) |
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| 107 | |
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| 108 | at_i(:,:) = SUM( a_i, dim=3 ) |
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| 109 | !------------------------------------------------------------------------------! |
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| 110 | ! 1) Compute thickness, salinity, enthalpy, age, area and volume of new ice |
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| 111 | !------------------------------------------------------------------------------! |
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| 112 | ! it occurs if cooling |
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| 113 | |
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| 114 | ! Identify grid points where new ice forms |
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| 115 | npti = 0 ; nptidx(:) = 0 |
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| 116 | DO_2D( nn_hls, nn_hls, nn_hls, nn_hls ) |
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| 117 | IF ( qlead(ji,jj) < 0._wp ) THEN |
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| 118 | npti = npti + 1 |
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| 119 | nptidx( npti ) = (jj - 1) * jpi + ji |
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| 120 | ENDIF |
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| 121 | END_2D |
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| 122 | |
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| 123 | ! Move from 2-D to 1-D vectors |
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| 124 | IF ( npti > 0 ) THEN |
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| 125 | |
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| 126 | CALL tab_2d_1d( npti, nptidx(1:npti), at_i_1d(1:npti) , at_i ) |
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| 127 | CALL tab_3d_2d( npti, nptidx(1:npti), a_i_2d (1:npti,1:jpl), a_i (:,:,:) ) |
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| 128 | CALL tab_3d_2d( npti, nptidx(1:npti), v_i_2d (1:npti,1:jpl), v_i (:,:,:) ) |
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| 129 | CALL tab_3d_2d( npti, nptidx(1:npti), sv_i_2d(1:npti,1:jpl), sv_i(:,:,:) ) |
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| 130 | DO jl = 1, jpl |
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| 131 | DO jk = 1, nlay_i |
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| 132 | CALL tab_2d_1d( npti, nptidx(1:npti), ze_i_2d(1:npti,jk,jl), e_i(:,:,jk,jl) ) |
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| 133 | END DO |
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| 134 | END DO |
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| 135 | CALL tab_2d_1d( npti, nptidx(1:npti), qlead_1d (1:npti) , qlead ) |
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| 136 | CALL tab_2d_1d( npti, nptidx(1:npti), t_bo_1d (1:npti) , t_bo ) |
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| 137 | CALL tab_2d_1d( npti, nptidx(1:npti), sfx_opw_1d (1:npti) , sfx_opw ) |
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| 138 | CALL tab_2d_1d( npti, nptidx(1:npti), wfx_opw_1d (1:npti) , wfx_opw ) |
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| 139 | CALL tab_2d_1d( npti, nptidx(1:npti), zh_newice (1:npti) , ht_i_new ) |
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| 140 | CALL tab_2d_1d( npti, nptidx(1:npti), zfraz_frac_1d(1:npti) , fraz_frac ) |
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| 141 | |
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| 142 | CALL tab_2d_1d( npti, nptidx(1:npti), hfx_thd_1d(1:npti) , hfx_thd ) |
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| 143 | CALL tab_2d_1d( npti, nptidx(1:npti), hfx_opw_1d(1:npti) , hfx_opw ) |
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| 144 | CALL tab_2d_1d( npti, nptidx(1:npti), rn_amax_1d(1:npti) , rn_amax_2d ) |
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| 145 | CALL tab_2d_1d( npti, nptidx(1:npti), sss_1d (1:npti) , sss_m ) |
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| 146 | |
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| 147 | ! Convert units for ice internal energy |
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| 148 | DO jl = 1, jpl |
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| 149 | DO jk = 1, nlay_i |
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| 150 | WHERE( v_i_2d(1:npti,jl) > 0._wp ) |
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| 151 | ze_i_2d(1:npti,jk,jl) = ze_i_2d(1:npti,jk,jl) / v_i_2d(1:npti,jl) * REAL( nlay_i ) |
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| 152 | ELSEWHERE |
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| 153 | ze_i_2d(1:npti,jk,jl) = 0._wp |
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| 154 | END WHERE |
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| 155 | END DO |
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| 156 | END DO |
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| 157 | |
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| 158 | ! Keep old ice areas and volume in memory |
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| 159 | zv_b(1:npti,:) = v_i_2d(1:npti,:) |
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| 160 | za_b(1:npti,:) = a_i_2d(1:npti,:) |
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| 161 | |
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| 162 | ! --- Salinity of new ice --- ! |
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| 163 | SELECT CASE ( nn_icesal ) |
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| 164 | CASE ( 1 ) ! Sice = constant |
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| 165 | zs_newice(1:npti) = rn_icesal |
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| 166 | CASE ( 2 ) ! Sice = F(z,t) [Vancoppenolle et al (2005)] |
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| 167 | DO ji = 1, npti |
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| 168 | zs_newice(ji) = MIN( 4.606 + 0.91 / zh_newice(ji) , rn_simax , 0.5 * sss_1d(ji) ) |
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| 169 | END DO |
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| 170 | CASE ( 3 ) ! Sice = F(z) [multiyear ice] |
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| 171 | zs_newice(1:npti) = 2.3 |
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| 172 | END SELECT |
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| 173 | |
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| 174 | ! --- Heat content of new ice --- ! |
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| 175 | ! We assume that new ice is formed at the seawater freezing point |
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| 176 | DO ji = 1, npti |
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| 177 | ztmelts = - rTmlt * zs_newice(ji) ! Melting point (C) |
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| 178 | ze_newice(ji) = rhoi * ( rcpi * ( ztmelts - ( t_bo_1d(ji) - rt0 ) ) & |
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| 179 | & + rLfus * ( 1.0 - ztmelts / MIN( t_bo_1d(ji) - rt0, -epsi10 ) ) & |
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| 180 | & - rcp * ztmelts ) |
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| 181 | END DO |
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| 182 | |
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| 183 | ! --- Age of new ice --- ! |
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| 184 | zo_newice(1:npti) = 0._wp |
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| 185 | |
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| 186 | ! --- Volume of new ice --- ! |
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| 187 | DO ji = 1, npti |
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| 188 | |
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| 189 | zEi = - ze_newice(ji) * r1_rhoi ! specific enthalpy of forming ice [J/kg] |
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| 190 | |
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| 191 | zEw = rcp * ( t_bo_1d(ji) - rt0 ) ! specific enthalpy of seawater at t_bo_1d [J/kg] |
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| 192 | ! clem: we suppose we are already at the freezing point (condition qlead<0 is satisfyied) |
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| 193 | |
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| 194 | zdE = zEi - zEw ! specific enthalpy difference [J/kg] |
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| 195 | |
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| 196 | zfmdt = - qlead_1d(ji) / zdE ! Fm.dt [kg/m2] (<0) |
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| 197 | ! clem: we use qlead instead of zqld (icethd) because we suppose we are at the freezing point |
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| 198 | zv_newice(ji) = - zfmdt * r1_rhoi |
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| 199 | |
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| 200 | zQm = zfmdt * zEw ! heat to the ocean >0 associated with mass flux |
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| 201 | |
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| 202 | ! Contribution to heat flux to the ocean [W.m-2], >0 |
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| 203 | hfx_thd_1d(ji) = hfx_thd_1d(ji) + zfmdt * zEw * r1_Dt_ice |
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| 204 | ! Total heat flux used in this process [W.m-2] |
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| 205 | hfx_opw_1d(ji) = hfx_opw_1d(ji) - zfmdt * zdE * r1_Dt_ice |
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| 206 | ! mass flux |
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| 207 | wfx_opw_1d(ji) = wfx_opw_1d(ji) - zv_newice(ji) * rhoi * r1_Dt_ice |
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| 208 | ! salt flux |
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| 209 | sfx_opw_1d(ji) = sfx_opw_1d(ji) - zv_newice(ji) * rhoi * zs_newice(ji) * r1_Dt_ice |
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| 210 | END DO |
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| 211 | |
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| 212 | ! A fraction fraz_frac of frazil ice is accreted at the ice bottom |
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| 213 | DO ji = 1, npti |
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| 214 | rswitch = 1._wp - MAX( 0._wp, SIGN( 1._wp , - at_i_1d(ji) ) ) |
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| 215 | zv_frazb(ji) = zfraz_frac_1d(ji) * rswitch * zv_newice(ji) |
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| 216 | zv_newice(ji) = ( 1._wp - zfraz_frac_1d(ji) * rswitch ) * zv_newice(ji) |
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| 217 | END DO |
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| 218 | |
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| 219 | ! --- Area of new ice --- ! |
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| 220 | DO ji = 1, npti |
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| 221 | za_newice(ji) = zv_newice(ji) / zh_newice(ji) |
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| 222 | END DO |
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| 223 | |
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| 224 | !------------------------------------------------------------------------------! |
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| 225 | ! 2) Redistribute new ice area and volume into ice categories ! |
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| 226 | !------------------------------------------------------------------------------! |
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| 227 | |
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| 228 | ! --- lateral ice growth --- ! |
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| 229 | ! If lateral ice growth gives an ice concentration > amax, then |
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| 230 | ! we keep the excessive volume in memory and attribute it later to bottom accretion |
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| 231 | DO ji = 1, npti |
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| 232 | IF ( za_newice(ji) > MAX( 0._wp, rn_amax_1d(ji) - at_i_1d(ji) ) ) THEN ! max is for roundoff error |
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| 233 | zda_res(ji) = za_newice(ji) - MAX( 0._wp, rn_amax_1d(ji) - at_i_1d(ji) ) |
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| 234 | zdv_res(ji) = zda_res (ji) * zh_newice(ji) |
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| 235 | za_newice(ji) = MAX( 0._wp, za_newice(ji) - zda_res (ji) ) |
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| 236 | zv_newice(ji) = MAX( 0._wp, zv_newice(ji) - zdv_res (ji) ) |
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| 237 | ELSE |
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| 238 | zda_res(ji) = 0._wp |
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| 239 | zdv_res(ji) = 0._wp |
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| 240 | ENDIF |
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| 241 | END DO |
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| 242 | |
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| 243 | ! find which category to fill |
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| 244 | DO jl = 1, jpl |
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| 245 | DO ji = 1, npti |
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| 246 | IF( zh_newice(ji) > hi_max(jl-1) .AND. zh_newice(ji) <= hi_max(jl) ) THEN |
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| 247 | a_i_2d(ji,jl) = a_i_2d(ji,jl) + za_newice(ji) |
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| 248 | v_i_2d(ji,jl) = v_i_2d(ji,jl) + zv_newice(ji) |
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| 249 | jcat(ji) = jl |
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| 250 | ENDIF |
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| 251 | END DO |
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| 252 | END DO |
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| 253 | at_i_1d(1:npti) = SUM( a_i_2d(1:npti,:), dim=2 ) |
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| 254 | |
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| 255 | ! Heat content |
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| 256 | DO ji = 1, npti |
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| 257 | jl = jcat(ji) ! categroy in which new ice is put |
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| 258 | zswinew (ji) = MAX( 0._wp , SIGN( 1._wp , - za_b(ji,jl) ) ) ! 0 if old ice |
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| 259 | END DO |
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| 260 | |
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| 261 | DO jk = 1, nlay_i |
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| 262 | DO ji = 1, npti |
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| 263 | jl = jcat(ji) |
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| 264 | rswitch = MAX( 0._wp, SIGN( 1._wp , v_i_2d(ji,jl) - epsi20 ) ) |
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| 265 | ze_i_2d(ji,jk,jl) = zswinew(ji) * ze_newice(ji) + & |
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| 266 | & ( 1.0 - zswinew(ji) ) * ( ze_newice(ji) * zv_newice(ji) + ze_i_2d(ji,jk,jl) * zv_b(ji,jl) ) & |
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| 267 | & * rswitch / MAX( v_i_2d(ji,jl), epsi20 ) |
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| 268 | END DO |
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| 269 | END DO |
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| 270 | |
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| 271 | ! --- bottom ice growth + ice enthalpy remapping --- ! |
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| 272 | DO jl = 1, jpl |
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| 273 | |
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| 274 | ! for remapping |
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| 275 | h_i_old (1:npti,0:nlay_i+1) = 0._wp |
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| 276 | eh_i_old(1:npti,0:nlay_i+1) = 0._wp |
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| 277 | DO jk = 1, nlay_i |
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| 278 | DO ji = 1, npti |
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| 279 | h_i_old (ji,jk) = v_i_2d(ji,jl) * r1_nlay_i |
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| 280 | eh_i_old(ji,jk) = ze_i_2d(ji,jk,jl) * h_i_old(ji,jk) |
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| 281 | END DO |
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| 282 | END DO |
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| 283 | |
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| 284 | ! new volumes including lateral/bottom accretion + residual |
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| 285 | DO ji = 1, npti |
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| 286 | rswitch = MAX( 0._wp, SIGN( 1._wp , at_i_1d(ji) - epsi20 ) ) |
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| 287 | zv_newfra = rswitch * ( zdv_res(ji) + zv_frazb(ji) ) * a_i_2d(ji,jl) / MAX( at_i_1d(ji) , epsi20 ) |
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| 288 | a_i_2d(ji,jl) = rswitch * a_i_2d(ji,jl) |
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| 289 | v_i_2d(ji,jl) = v_i_2d(ji,jl) + zv_newfra |
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| 290 | ! for remapping |
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| 291 | h_i_old (ji,nlay_i+1) = zv_newfra |
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| 292 | eh_i_old(ji,nlay_i+1) = ze_newice(ji) * zv_newfra |
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| 293 | END DO |
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| 294 | ! --- Ice enthalpy remapping --- ! |
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| 295 | CALL ice_thd_ent( ze_i_2d(1:npti,:,jl) ) |
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| 296 | END DO |
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| 297 | |
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| 298 | ! --- Update salinity --- ! |
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| 299 | DO jl = 1, jpl |
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| 300 | DO ji = 1, npti |
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| 301 | sv_i_2d(ji,jl) = sv_i_2d(ji,jl) + zs_newice(ji) * ( v_i_2d(ji,jl) - zv_b(ji,jl) ) |
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| 302 | END DO |
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| 303 | END DO |
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| 304 | |
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| 305 | ! Change units for e_i |
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| 306 | DO jl = 1, jpl |
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| 307 | DO jk = 1, nlay_i |
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| 308 | ze_i_2d(1:npti,jk,jl) = ze_i_2d(1:npti,jk,jl) * v_i_2d(1:npti,jl) * r1_nlay_i |
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| 309 | END DO |
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| 310 | END DO |
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| 311 | |
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| 312 | ! Move 2D vectors to 1D vectors |
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| 313 | CALL tab_2d_3d( npti, nptidx(1:npti), a_i_2d (1:npti,1:jpl), a_i (:,:,:) ) |
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| 314 | CALL tab_2d_3d( npti, nptidx(1:npti), v_i_2d (1:npti,1:jpl), v_i (:,:,:) ) |
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| 315 | CALL tab_2d_3d( npti, nptidx(1:npti), sv_i_2d(1:npti,1:jpl), sv_i(:,:,:) ) |
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| 316 | DO jl = 1, jpl |
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| 317 | DO jk = 1, nlay_i |
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| 318 | CALL tab_1d_2d( npti, nptidx(1:npti), ze_i_2d(1:npti,jk,jl), e_i(:,:,jk,jl) ) |
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| 319 | END DO |
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| 320 | END DO |
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| 321 | CALL tab_1d_2d( npti, nptidx(1:npti), sfx_opw_1d(1:npti), sfx_opw ) |
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| 322 | CALL tab_1d_2d( npti, nptidx(1:npti), wfx_opw_1d(1:npti), wfx_opw ) |
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| 323 | CALL tab_1d_2d( npti, nptidx(1:npti), hfx_thd_1d(1:npti), hfx_thd ) |
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| 324 | CALL tab_1d_2d( npti, nptidx(1:npti), hfx_opw_1d(1:npti), hfx_opw ) |
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| 325 | ! |
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| 326 | ENDIF ! npti > 0 |
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| 327 | ! |
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| 328 | IF( ln_icediachk ) CALL ice_cons_hsm(1, 'icethd_do', rdiag_v, rdiag_s, rdiag_t, rdiag_fv, rdiag_fs, rdiag_ft) |
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| 329 | IF( ln_icediachk ) CALL ice_cons2D (1, 'icethd_do', diag_v, diag_s, diag_t, diag_fv, diag_fs, diag_ft) |
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| 330 | ! |
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| 331 | END SUBROUTINE ice_thd_do |
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| 332 | |
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| 333 | |
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| 334 | SUBROUTINE ice_thd_frazil |
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| 335 | !!----------------------------------------------------------------------- |
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| 336 | !! *** ROUTINE ice_thd_frazil *** |
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| 337 | !! |
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| 338 | !! ** Purpose : frazil ice collection thickness and fraction |
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| 339 | !! |
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| 340 | !! ** Inputs : u_ice, v_ice, utau_ice, vtau_ice |
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| 341 | !! ** Ouputs : ht_i_new, fraz_frac |
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| 342 | !!----------------------------------------------------------------------- |
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| 343 | INTEGER :: ji, jj ! dummy loop indices |
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| 344 | INTEGER :: iter |
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| 345 | REAL(wp) :: zvfrx, zvgx, ztaux, zf, ztenagm, zvfry, zvgy, ztauy, zvrel2, zfp, ztwogp |
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| 346 | REAL(wp), PARAMETER :: zcai = 1.4e-3_wp ! ice-air drag (clem: should be dependent on coupling/forcing used) |
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| 347 | REAL(wp), PARAMETER :: zhicrit = 0.04_wp ! frazil ice thickness |
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| 348 | REAL(wp), PARAMETER :: zsqcd = 1.0_wp / SQRT( 1.3_wp * zcai ) ! 1/SQRT(airdensity*drag) |
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| 349 | REAL(wp), PARAMETER :: zgamafr = 0.03_wp |
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| 350 | !!----------------------------------------------------------------------- |
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| 351 | ! |
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| 352 | !---------------------------------------------------------! |
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| 353 | ! Collection thickness of ice formed in leads and polynyas |
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| 354 | !---------------------------------------------------------! |
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| 355 | ! ht_i_new is the thickness of new ice formed in open water |
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| 356 | ! ht_i_new can be either prescribed (ln_frazil=F) or computed (ln_frazil=T) |
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| 357 | ! Frazil ice forms in open water, is transported by wind, accumulates at the edge of the consolidated ice edge |
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| 358 | ! where it forms aggregates of a specific thickness called collection thickness. |
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| 359 | ! |
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| 360 | fraz_frac(:,:) = 0._wp |
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| 361 | ! |
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| 362 | ! Default new ice thickness |
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| 363 | WHERE( qlead(:,:) < 0._wp ) ! cooling |
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| 364 | ht_i_new(:,:) = rn_hinew |
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| 365 | ELSEWHERE |
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| 366 | ht_i_new(:,:) = 0._wp |
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| 367 | END WHERE |
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| 368 | |
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| 369 | IF( ln_frazil ) THEN |
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| 370 | ztwogp = 2._wp * rho0 / ( grav * 0.3_wp * ( rho0 - rhoi ) ) ! reduced grav |
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| 371 | ! |
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| 372 | DO_2D( 0, 0, 0, 0 ) |
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| 373 | IF ( qlead(ji,jj) < 0._wp ) THEN ! cooling |
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| 374 | ! -- Wind stress -- ! |
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| 375 | ztaux = ( utau_ice(ji-1,jj ) * umask(ji-1,jj ,1) + utau_ice(ji,jj) * umask(ji,jj,1) ) * 0.5_wp |
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| 376 | ztauy = ( vtau_ice(ji ,jj-1) * vmask(ji ,jj-1,1) + vtau_ice(ji,jj) * vmask(ji,jj,1) ) * 0.5_wp |
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| 377 | ! Square root of wind stress |
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| 378 | ztenagm = SQRT( SQRT( ztaux * ztaux + ztauy * ztauy ) ) |
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| 379 | |
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| 380 | ! -- Frazil ice velocity -- ! |
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| 381 | rswitch = MAX( 0._wp, SIGN( 1._wp , ztenagm - epsi10 ) ) |
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| 382 | zvfrx = rswitch * zgamafr * zsqcd * ztaux / MAX( ztenagm, epsi10 ) |
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| 383 | zvfry = rswitch * zgamafr * zsqcd * ztauy / MAX( ztenagm, epsi10 ) |
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| 384 | |
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| 385 | ! -- Pack ice velocity -- ! |
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| 386 | zvgx = ( u_ice(ji-1,jj ) * umask(ji-1,jj ,1) + u_ice(ji,jj) * umask(ji,jj,1) ) * 0.5_wp |
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| 387 | zvgy = ( v_ice(ji ,jj-1) * vmask(ji ,jj-1,1) + v_ice(ji,jj) * vmask(ji,jj,1) ) * 0.5_wp |
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| 388 | |
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| 389 | ! -- Relative frazil/pack ice velocity -- ! |
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| 390 | rswitch = MAX( 0._wp, SIGN( 1._wp , at_i(ji,jj) - epsi10 ) ) |
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| 391 | zvrel2 = MAX( (zvfrx - zvgx)*(zvfrx - zvgx) + (zvfry - zvgy)*(zvfry - zvgy), 0.15_wp*0.15_wp ) * rswitch |
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| 392 | |
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| 393 | ! -- fraction of frazil ice -- ! |
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| 394 | fraz_frac(ji,jj) = rswitch * ( TANH( rn_Cfraz * ( SQRT(zvrel2) - rn_vfraz ) ) + 1._wp ) * 0.5_wp * rn_maxfraz |
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| 395 | |
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| 396 | ! -- new ice thickness (iterative loop) -- ! |
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| 397 | ht_i_new(ji,jj) = zhicrit + ( zhicrit + 0.1_wp ) & |
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| 398 | & / ( ( zhicrit + 0.1_wp ) * ( zhicrit + 0.1_wp ) - zhicrit * zhicrit ) * ztwogp * zvrel2 |
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| 399 | iter = 1 |
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| 400 | DO WHILE ( iter < 20 ) |
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| 401 | zf = ( ht_i_new(ji,jj) - zhicrit ) * ( ht_i_new(ji,jj) * ht_i_new(ji,jj) - zhicrit * zhicrit ) - & |
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| 402 | & ht_i_new(ji,jj) * zhicrit * ztwogp * zvrel2 |
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| 403 | zfp = ( ht_i_new(ji,jj) - zhicrit ) * ( 3.0_wp * ht_i_new(ji,jj) + zhicrit ) - zhicrit * ztwogp * zvrel2 |
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| 404 | |
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| 405 | ht_i_new(ji,jj) = ht_i_new(ji,jj) - zf / MAX( zfp, epsi20 ) |
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| 406 | iter = iter + 1 |
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| 407 | END DO |
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| 408 | ! |
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| 409 | ! bound ht_i_new (though I don't see why it should be necessary) |
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| 410 | ht_i_new(ji,jj) = MAX( 0.01_wp, MIN( ht_i_new(ji,jj), hi_max(jpl) ) ) |
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| 411 | ! |
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| 412 | ELSE |
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| 413 | ht_i_new(ji,jj) = 0._wp |
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| 414 | ENDIF |
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| 415 | ! |
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| 416 | END_2D |
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| 417 | ! |
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| 418 | CALL lbc_lnk( 'icethd_frazil', fraz_frac, 'T', 1.0_wp, ht_i_new, 'T', 1.0_wp ) |
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| 419 | |
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| 420 | ENDIF |
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| 421 | END SUBROUTINE ice_thd_frazil |
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| 422 | |
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| 423 | |
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| 424 | SUBROUTINE ice_thd_do_init |
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| 425 | !!----------------------------------------------------------------------- |
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| 426 | !! *** ROUTINE ice_thd_do_init *** |
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| 427 | !! |
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| 428 | !! ** Purpose : Physical constants and parameters associated with |
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| 429 | !! ice growth in the leads |
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| 430 | !! |
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| 431 | !! ** Method : Read the namthd_do namelist and check the parameters |
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| 432 | !! called at the first timestep (nit000) |
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| 433 | !! |
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| 434 | !! ** input : Namelist namthd_do |
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| 435 | !!------------------------------------------------------------------- |
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| 436 | INTEGER :: ios ! Local integer |
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| 437 | !! |
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| 438 | NAMELIST/namthd_do/ rn_hinew, ln_frazil, rn_maxfraz, rn_vfraz, rn_Cfraz |
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| 439 | !!------------------------------------------------------------------- |
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| 440 | ! |
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| 441 | READ ( numnam_ice_ref, namthd_do, IOSTAT = ios, ERR = 901) |
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| 442 | 901 IF( ios /= 0 ) CALL ctl_nam ( ios , 'namthd_do in reference namelist' ) |
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| 443 | READ ( numnam_ice_cfg, namthd_do, IOSTAT = ios, ERR = 902 ) |
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| 444 | 902 IF( ios > 0 ) CALL ctl_nam ( ios , 'namthd_do in configuration namelist' ) |
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| 445 | IF(lwm) WRITE( numoni, namthd_do ) |
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| 446 | ! |
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| 447 | IF(lwp) THEN ! control print |
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| 448 | WRITE(numout,*) |
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| 449 | WRITE(numout,*) 'ice_thd_do_init: Ice growth in open water' |
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| 450 | WRITE(numout,*) '~~~~~~~~~~~~~~~' |
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| 451 | WRITE(numout,*) ' Namelist namthd_do:' |
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| 452 | WRITE(numout,*) ' ice thickness for lateral accretion rn_hinew = ', rn_hinew |
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| 453 | WRITE(numout,*) ' Frazil ice thickness as a function of wind or not ln_frazil = ', ln_frazil |
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| 454 | WRITE(numout,*) ' Maximum proportion of frazil ice collecting at bottom rn_maxfraz = ', rn_maxfraz |
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| 455 | WRITE(numout,*) ' Threshold relative drift speed for collection of frazil rn_vfraz = ', rn_vfraz |
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| 456 | WRITE(numout,*) ' Squeezing coefficient for collection of frazil rn_Cfraz = ', rn_Cfraz |
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| 457 | ENDIF |
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| 458 | ! |
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| 459 | IF ( rn_hinew < rn_himin ) CALL ctl_stop( 'ice_thd_do_init : rn_hinew should be >= rn_himin' ) |
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| 460 | ! |
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| 461 | END SUBROUTINE ice_thd_do_init |
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| 462 | |
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| 463 | #else |
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| 464 | !!---------------------------------------------------------------------- |
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| 465 | !! Default option NO SI3 sea-ice model |
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| 466 | !!---------------------------------------------------------------------- |
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| 467 | #endif |
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| 468 | |
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| 469 | !!====================================================================== |
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| 470 | END MODULE icethd_do |
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