[825] | 1 | MODULE limthd_dh |
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[1572] | 2 | !!====================================================================== |
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| 3 | !! *** MODULE limthd_dh *** |
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| 4 | !! LIM-3 : thermodynamic growth and decay of the ice |
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| 5 | !!====================================================================== |
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| 6 | !! History : LIM ! 2003-05 (M. Vancoppenolle) Original code in 1D |
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| 7 | !! ! 2005-06 (M. Vancoppenolle) 3D version |
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[4688] | 8 | !! 3.2 ! 2009-07 (M. Vancoppenolle, Y. Aksenov, G. Madec) bug correction in wfx_snw & wfx_ice |
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[3625] | 9 | !! 3.4 ! 2011-02 (G. Madec) dynamical allocation |
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| 10 | !! 3.5 ! 2012-10 (G. Madec & co) salt flux + bug fixes |
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[1572] | 11 | !!---------------------------------------------------------------------- |
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[825] | 12 | #if defined key_lim3 |
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[834] | 13 | !!---------------------------------------------------------------------- |
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| 14 | !! 'key_lim3' LIM3 sea-ice model |
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| 15 | !!---------------------------------------------------------------------- |
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[3625] | 16 | !! lim_thd_dh : vertical accr./abl. and lateral ablation of sea ice |
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[825] | 17 | !!---------------------------------------------------------------------- |
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[3625] | 18 | USE par_oce ! ocean parameters |
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| 19 | USE phycst ! physical constants (OCE directory) |
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| 20 | USE sbc_oce ! Surface boundary condition: ocean fields |
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| 21 | USE ice ! LIM variables |
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| 22 | USE thd_ice ! LIM thermodynamics |
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| 23 | USE in_out_manager ! I/O manager |
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| 24 | USE lib_mpp ! MPP library |
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| 25 | USE wrk_nemo ! work arrays |
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| 26 | USE lib_fortran ! Fortran utilities (allows no signed zero when 'key_nosignedzero' defined) |
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[4688] | 27 | |
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[825] | 28 | IMPLICIT NONE |
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| 29 | PRIVATE |
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| 30 | |
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[1572] | 31 | PUBLIC lim_thd_dh ! called by lim_thd |
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[825] | 32 | |
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| 33 | !!---------------------------------------------------------------------- |
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[4161] | 34 | !! NEMO/LIM3 4.0 , UCL - NEMO Consortium (2010) |
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[1156] | 35 | !! $Id$ |
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[2715] | 36 | !! Software governed by the CeCILL licence (NEMOGCM/NEMO_CeCILL.txt) |
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[825] | 37 | !!---------------------------------------------------------------------- |
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| 38 | CONTAINS |
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| 39 | |
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[4688] | 40 | SUBROUTINE lim_thd_dh( kideb, kiut ) |
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[921] | 41 | !!------------------------------------------------------------------ |
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| 42 | !! *** ROUTINE lim_thd_dh *** |
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| 43 | !! |
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[1572] | 44 | !! ** Purpose : determines variations of ice and snow thicknesses. |
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[921] | 45 | !! |
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[1572] | 46 | !! ** Method : Ice/Snow surface melting arises from imbalance in surface fluxes |
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| 47 | !! Bottom accretion/ablation arises from flux budget |
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| 48 | !! Snow thickness can increase by precipitation and decrease by sublimation |
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| 49 | !! If snow load excesses Archmiede limit, snow-ice is formed by |
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| 50 | !! the flooding of sea-water in the snow |
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[921] | 51 | !! |
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[1572] | 52 | !! 1) Compute available flux of heat for surface ablation |
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| 53 | !! 2) Compute snow and sea ice enthalpies |
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| 54 | !! 3) Surface ablation and sublimation |
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| 55 | !! 4) Bottom accretion/ablation |
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| 56 | !! 5) Case of Total ablation |
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| 57 | !! 6) Snow ice formation |
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[921] | 58 | !! |
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[1572] | 59 | !! References : Bitz and Lipscomb, 1999, J. Geophys. Res. |
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| 60 | !! Fichefet T. and M. Maqueda 1997, J. Geophys. Res., 102(C6), 12609-12646 |
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| 61 | !! Vancoppenolle, Fichefet and Bitz, 2005, Geophys. Res. Let. |
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| 62 | !! Vancoppenolle et al.,2009, Ocean Modelling |
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[921] | 63 | !!------------------------------------------------------------------ |
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[1572] | 64 | INTEGER , INTENT(in) :: kideb, kiut ! Start/End point on which the the computation is applied |
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| 65 | !! |
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| 66 | INTEGER :: ji , jk ! dummy loop indices |
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[4161] | 67 | INTEGER :: ii, ij ! 2D corresponding indices to ji |
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[1572] | 68 | INTEGER :: iter |
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[825] | 69 | |
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[4688] | 70 | REAL(wp) :: ztmelts ! local scalar |
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[5123] | 71 | REAL(wp) :: zfdum |
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[1572] | 72 | REAL(wp) :: zfracs ! fractionation coefficient for bottom salt entrapment |
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| 73 | REAL(wp) :: zcoeff ! dummy argument for snowfall partitioning over ice and leads |
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[4688] | 74 | REAL(wp) :: zs_snic ! snow-ice salinity |
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[1572] | 75 | REAL(wp) :: zswi1 ! switch for computation of bottom salinity |
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| 76 | REAL(wp) :: zswi12 ! switch for computation of bottom salinity |
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| 77 | REAL(wp) :: zswi2 ! switch for computation of bottom salinity |
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| 78 | REAL(wp) :: zgrr ! bottom growth rate |
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[4688] | 79 | REAL(wp) :: zt_i_new ! bottom formation temperature |
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| 80 | |
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| 81 | REAL(wp) :: zQm ! enthalpy exchanged with the ocean (J/m2), >0 towards the ocean |
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| 82 | REAL(wp) :: zEi ! specific enthalpy of sea ice (J/kg) |
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| 83 | REAL(wp) :: zEw ! specific enthalpy of exchanged water (J/kg) |
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| 84 | REAL(wp) :: zdE ! specific enthalpy difference (J/kg) |
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| 85 | REAL(wp) :: zfmdt ! exchange mass flux x time step (J/m2), >0 towards the ocean |
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| 86 | REAL(wp) :: zsstK ! SST in Kelvin |
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| 87 | |
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| 88 | REAL(wp), POINTER, DIMENSION(:) :: zqprec ! energy of fallen snow (J.m-3) |
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| 89 | REAL(wp), POINTER, DIMENSION(:) :: zq_su ! heat for surface ablation (J.m-2) |
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| 90 | REAL(wp), POINTER, DIMENSION(:) :: zq_bo ! heat for bottom ablation (J.m-2) |
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| 91 | REAL(wp), POINTER, DIMENSION(:) :: zq_rema ! remaining heat at the end of the routine (J.m-2) |
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[5123] | 92 | REAL(wp), POINTER, DIMENSION(:) :: zf_tt ! Heat budget to determine melting or freezing(W.m-2) |
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[3294] | 93 | |
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[3625] | 94 | REAL(wp), POINTER, DIMENSION(:) :: zdh_s_mel ! snow melt |
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| 95 | REAL(wp), POINTER, DIMENSION(:) :: zdh_s_pre ! snow precipitation |
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| 96 | REAL(wp), POINTER, DIMENSION(:) :: zdh_s_sub ! snow sublimation |
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[3294] | 97 | |
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| 98 | REAL(wp), POINTER, DIMENSION(:,:) :: zdeltah |
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[4688] | 99 | REAL(wp), POINTER, DIMENSION(:,:) :: zh_i ! ice layer thickness |
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[5350] | 100 | INTEGER , POINTER, DIMENSION(:,:) :: icount ! number of layers vanished by melting |
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[3294] | 101 | |
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[4688] | 102 | REAL(wp), POINTER, DIMENSION(:) :: zqh_i ! total ice heat content (J.m-2) |
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| 103 | REAL(wp), POINTER, DIMENSION(:) :: zqh_s ! total snow heat content (J.m-2) |
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| 104 | REAL(wp), POINTER, DIMENSION(:) :: zq_s ! total snow enthalpy (J.m-3) |
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[3294] | 105 | |
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[5123] | 106 | REAL(wp) :: zswitch_sal |
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[4161] | 107 | |
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[3294] | 108 | ! Heat conservation |
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[4688] | 109 | INTEGER :: num_iter_max |
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| 110 | |
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[1572] | 111 | !!------------------------------------------------------------------ |
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[825] | 112 | |
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[5123] | 113 | ! Discriminate between varying salinity (nn_icesal=2) and prescribed cases (other values) |
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| 114 | SELECT CASE( nn_icesal ) ! varying salinity or not |
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[4688] | 115 | CASE( 1, 3, 4 ) ; zswitch_sal = 0 ! prescribed salinity profile |
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| 116 | CASE( 2 ) ; zswitch_sal = 1 ! varying salinity profile |
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| 117 | END SELECT |
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[825] | 118 | |
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[5350] | 119 | CALL wrk_alloc( jpij, zqprec, zq_su, zq_bo, zf_tt, zq_rema ) |
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[4688] | 120 | CALL wrk_alloc( jpij, zdh_s_mel, zdh_s_pre, zdh_s_sub, zqh_i, zqh_s, zq_s ) |
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[5350] | 121 | CALL wrk_alloc( jpij, nlay_i, zdeltah, zh_i ) |
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| 122 | CALL wrk_alloc( jpij, nlay_i, icount ) |
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[4161] | 123 | |
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[4688] | 124 | dh_i_surf (:) = 0._wp ; dh_i_bott (:) = 0._wp ; dh_snowice(:) = 0._wp |
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| 125 | dsm_i_se_1d(:) = 0._wp ; dsm_i_si_1d(:) = 0._wp |
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| 126 | |
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| 127 | zqprec (:) = 0._wp ; zq_su (:) = 0._wp ; zq_bo (:) = 0._wp ; zf_tt (:) = 0._wp |
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[5123] | 128 | zq_rema(:) = 0._wp |
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[2715] | 129 | |
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[4688] | 130 | zdh_s_pre(:) = 0._wp |
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| 131 | zdh_s_mel(:) = 0._wp |
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| 132 | zdh_s_sub(:) = 0._wp |
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| 133 | zqh_s (:) = 0._wp |
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| 134 | zqh_i (:) = 0._wp |
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[4161] | 135 | |
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[4688] | 136 | zh_i (:,:) = 0._wp |
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| 137 | zdeltah (:,:) = 0._wp |
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[5350] | 138 | icount (:,:) = 0 |
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[4688] | 139 | |
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[5350] | 140 | ! Initialize enthalpy at nlay_i+1 |
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| 141 | DO ji = kideb, kiut |
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| 142 | q_i_1d(ji,nlay_i+1) = 0._wp |
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| 143 | END DO |
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| 144 | |
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[4688] | 145 | ! initialize layer thicknesses and enthalpies |
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| 146 | h_i_old (:,0:nlay_i+1) = 0._wp |
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| 147 | qh_i_old(:,0:nlay_i+1) = 0._wp |
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| 148 | DO jk = 1, nlay_i |
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| 149 | DO ji = kideb, kiut |
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[5123] | 150 | h_i_old (ji,jk) = ht_i_1d(ji) * r1_nlay_i |
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[4872] | 151 | qh_i_old(ji,jk) = q_i_1d(ji,jk) * h_i_old(ji,jk) |
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[4688] | 152 | ENDDO |
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| 153 | ENDDO |
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[921] | 154 | ! |
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| 155 | !------------------------------------------------------------------------------! |
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[4688] | 156 | ! 1) Calculate available heat for surface and bottom ablation ! |
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[921] | 157 | !------------------------------------------------------------------------------! |
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| 158 | ! |
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[2715] | 159 | DO ji = kideb, kiut |
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[4990] | 160 | zfdum = qns_ice_1d(ji) + ( 1._wp - i0(ji) ) * qsr_ice_1d(ji) - fc_su(ji) |
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| 161 | zf_tt(ji) = fc_bo_i(ji) + fhtur_1d(ji) + fhld_1d(ji) |
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[4688] | 162 | |
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[5350] | 163 | zq_su (ji) = MAX( 0._wp, zfdum * rdt_ice ) * MAX( 0._wp , SIGN( 1._wp, t_su_1d(ji) - rt0 ) ) |
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[4688] | 164 | zq_bo (ji) = MAX( 0._wp, zf_tt(ji) * rdt_ice ) |
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| 165 | END DO |
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| 166 | |
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[921] | 167 | ! |
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| 168 | !------------------------------------------------------------------------------! |
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[4688] | 169 | ! If snow temperature is above freezing point, then snow melts |
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| 170 | ! (should not happen but sometimes it does) |
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[921] | 171 | !------------------------------------------------------------------------------! |
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[4688] | 172 | DO ji = kideb, kiut |
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[5123] | 173 | IF( t_s_1d(ji,1) > rt0 ) THEN !!! Internal melting |
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[4688] | 174 | ! Contribution to heat flux to the ocean [W.m-2], < 0 |
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[4872] | 175 | hfx_res_1d(ji) = hfx_res_1d(ji) + q_s_1d(ji,1) * ht_s_1d(ji) * a_i_1d(ji) * r1_rdtice |
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[4688] | 176 | ! Contribution to mass flux |
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[4872] | 177 | wfx_snw_1d(ji) = wfx_snw_1d(ji) + rhosn * ht_s_1d(ji) * a_i_1d(ji) * r1_rdtice |
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[4688] | 178 | ! updates |
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[4872] | 179 | ht_s_1d(ji) = 0._wp |
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| 180 | q_s_1d (ji,1) = 0._wp |
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[5123] | 181 | t_s_1d (ji,1) = rt0 |
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[4688] | 182 | END IF |
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| 183 | END DO |
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| 184 | |
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| 185 | !------------------------------------------------------------! |
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| 186 | ! 2) Computing layer thicknesses and enthalpies. ! |
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| 187 | !------------------------------------------------------------! |
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[921] | 188 | ! |
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[825] | 189 | DO jk = 1, nlay_s |
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[2715] | 190 | DO ji = kideb, kiut |
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[5350] | 191 | zqh_s(ji) = zqh_s(ji) + q_s_1d(ji,jk) * ht_s_1d(ji) * r1_nlay_s |
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[825] | 192 | END DO |
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| 193 | END DO |
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[2715] | 194 | ! |
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[825] | 195 | DO jk = 1, nlay_i |
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[2715] | 196 | DO ji = kideb, kiut |
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[5123] | 197 | zh_i(ji,jk) = ht_i_1d(ji) * r1_nlay_i |
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[4872] | 198 | zqh_i(ji) = zqh_i(ji) + q_i_1d(ji,jk) * zh_i(ji,jk) |
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[825] | 199 | END DO |
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| 200 | END DO |
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[921] | 201 | ! |
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| 202 | !------------------------------------------------------------------------------| |
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| 203 | ! 3) Surface ablation and sublimation | |
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| 204 | !------------------------------------------------------------------------------| |
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| 205 | ! |
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[834] | 206 | !------------------------- |
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| 207 | ! 3.1 Snow precips / melt |
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| 208 | !------------------------- |
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[825] | 209 | ! Snow accumulation in one thermodynamic time step |
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| 210 | ! snowfall is partitionned between leads and ice |
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| 211 | ! if snow fall was uniform, a fraction (1-at_i) would fall into leads |
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| 212 | ! but because of the winds, more snow falls on leads than on sea ice |
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| 213 | ! and a greater fraction (1-at_i)^beta of the total mass of snow |
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[834] | 214 | ! (beta < 1) falls in leads. |
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[825] | 215 | ! In reality, beta depends on wind speed, |
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| 216 | ! and should decrease with increasing wind speed but here, it is |
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[834] | 217 | ! considered as a constant. an average value is 0.66 |
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[825] | 218 | ! Martin Vancoppenolle, December 2006 |
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| 219 | |
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[5350] | 220 | zdeltah(:,:) = 0._wp |
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[825] | 221 | DO ji = kideb, kiut |
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[4688] | 222 | !----------- |
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| 223 | ! Snow fall |
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| 224 | !----------- |
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| 225 | ! thickness change |
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[5123] | 226 | zcoeff = ( 1._wp - ( 1._wp - at_i_1d(ji) )**rn_betas ) / at_i_1d(ji) |
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| 227 | zdh_s_pre(ji) = zcoeff * sprecip_1d(ji) * rdt_ice * r1_rhosn |
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[4688] | 228 | ! enthalpy of the precip (>0, J.m-3) (tatm_ice is now in K) |
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[5123] | 229 | zqprec (ji) = rhosn * ( cpic * ( rt0 - MIN( tatm_ice_1d(ji), rt0_snow) ) + lfus ) |
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[4688] | 230 | IF( sprecip_1d(ji) == 0._wp ) zqprec(ji) = 0._wp |
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| 231 | ! heat flux from snow precip (>0, W.m-2) |
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[4872] | 232 | hfx_spr_1d(ji) = hfx_spr_1d(ji) + zdh_s_pre(ji) * a_i_1d(ji) * zqprec(ji) * r1_rdtice |
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[4688] | 233 | ! mass flux, <0 |
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[4872] | 234 | wfx_spr_1d(ji) = wfx_spr_1d(ji) - rhosn * a_i_1d(ji) * zdh_s_pre(ji) * r1_rdtice |
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[825] | 235 | |
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[4688] | 236 | !--------------------- |
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| 237 | ! Melt of falling snow |
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| 238 | !--------------------- |
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| 239 | ! thickness change |
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[5134] | 240 | rswitch = MAX( 0._wp , SIGN( 1._wp , zqprec(ji) - epsi20 ) ) |
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[5350] | 241 | zdeltah (ji,1) = - rswitch * zq_su(ji) / MAX( zqprec(ji) , epsi20 ) |
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| 242 | zdeltah (ji,1) = MAX( - zdh_s_pre(ji), zdeltah(ji,1) ) ! bound melting |
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[4688] | 243 | ! heat used to melt snow (W.m-2, >0) |
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[5350] | 244 | hfx_snw_1d(ji) = hfx_snw_1d(ji) - zdeltah(ji,1) * a_i_1d(ji) * zqprec(ji) * r1_rdtice |
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[4688] | 245 | ! snow melting only = water into the ocean (then without snow precip), >0 |
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[5350] | 246 | wfx_snw_1d(ji) = wfx_snw_1d(ji) - rhosn * a_i_1d(ji) * zdeltah(ji,1) * r1_rdtice |
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| 247 | ! updates available heat + precipitations after melting |
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| 248 | zq_su (ji) = MAX( 0._wp , zq_su (ji) + zdeltah(ji,1) * zqprec(ji) ) |
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| 249 | zdh_s_pre (ji) = zdh_s_pre(ji) + zdeltah(ji,1) |
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[4688] | 250 | |
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[5350] | 251 | ! update thickness |
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| 252 | ht_s_1d(ji) = MAX( 0._wp , ht_s_1d(ji) + zdh_s_pre(ji) ) |
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[825] | 253 | END DO |
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| 254 | |
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[5350] | 255 | ! If heat still available (zq_su > 0), then melt more snow |
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| 256 | zdeltah(:,:) = 0._wp |
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[825] | 257 | DO jk = 1, nlay_s |
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| 258 | DO ji = kideb, kiut |
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[4688] | 259 | ! thickness change |
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[4990] | 260 | rswitch = 1._wp - MAX( 0._wp, SIGN( 1._wp, - ht_s_1d(ji) ) ) |
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[5134] | 261 | rswitch = rswitch * ( MAX( 0._wp, SIGN( 1._wp, q_s_1d(ji,jk) - epsi20 ) ) ) |
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[4990] | 262 | zdeltah (ji,jk) = - rswitch * zq_su(ji) / MAX( q_s_1d(ji,jk), epsi20 ) |
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[5350] | 263 | zdeltah (ji,jk) = MAX( zdeltah(ji,jk) , - ht_s_1d(ji) ) ! bound melting |
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[4688] | 264 | zdh_s_mel(ji) = zdh_s_mel(ji) + zdeltah(ji,jk) |
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| 265 | ! heat used to melt snow(W.m-2, >0) |
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[4872] | 266 | hfx_snw_1d(ji) = hfx_snw_1d(ji) - zdeltah(ji,jk) * a_i_1d(ji) * q_s_1d(ji,jk) * r1_rdtice |
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[4688] | 267 | ! snow melting only = water into the ocean (then without snow precip) |
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[4872] | 268 | wfx_snw_1d(ji) = wfx_snw_1d(ji) - rhosn * a_i_1d(ji) * zdeltah(ji,jk) * r1_rdtice |
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[4688] | 269 | ! updates available heat + thickness |
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[5123] | 270 | zq_su (ji) = MAX( 0._wp , zq_su (ji) + zdeltah(ji,jk) * q_s_1d(ji,jk) ) |
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[4872] | 271 | ht_s_1d(ji) = MAX( 0._wp , ht_s_1d(ji) + zdeltah(ji,jk) ) |
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[1572] | 272 | END DO |
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| 273 | END DO |
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[825] | 274 | |
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[4688] | 275 | !---------------------- |
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| 276 | ! 3.2 Snow sublimation |
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| 277 | !---------------------- |
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| 278 | ! qla_ice is always >=0 (upwards), heat goes to the atmosphere, therefore snow sublimates |
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[5350] | 279 | ! clem comment: not counted in mass/heat exchange in limsbc since this is an exchange with atm. (not ocean) |
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[4688] | 280 | ! clem comment: ice should also sublimate |
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[5350] | 281 | zdeltah(:,:) = 0._wp |
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[4688] | 282 | IF( lk_cpl ) THEN |
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| 283 | ! coupled mode: sublimation already included in emp_ice (to do in limsbc_ice) |
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| 284 | zdh_s_sub(:) = 0._wp |
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| 285 | ELSE |
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| 286 | ! forced mode: snow thickness change due to sublimation |
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[921] | 287 | DO ji = kideb, kiut |
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[5350] | 288 | zdh_s_sub(ji) = MAX( - ht_s_1d(ji) , - qla_ice_1d(ji) / ( rhosn * lsub ) * rdt_ice ) |
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[4688] | 289 | ! Heat flux by sublimation [W.m-2], < 0 |
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| 290 | ! sublimate first snow that had fallen, then pre-existing snow |
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[5350] | 291 | zdeltah(ji,1) = MAX( zdh_s_sub(ji), - zdh_s_pre(ji) ) |
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| 292 | hfx_sub_1d(ji) = hfx_sub_1d(ji) + ( zdeltah(ji,1) * zqprec(ji) + ( zdh_s_sub(ji) - zdeltah(ji,1) ) * q_s_1d(ji,1) & |
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| 293 | & ) * a_i_1d(ji) * r1_rdtice |
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[4688] | 294 | ! Mass flux by sublimation |
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[4872] | 295 | wfx_sub_1d(ji) = wfx_sub_1d(ji) - rhosn * a_i_1d(ji) * zdh_s_sub(ji) * r1_rdtice |
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[4688] | 296 | ! new snow thickness |
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[5350] | 297 | ht_s_1d(ji) = MAX( 0._wp , ht_s_1d(ji) + zdh_s_sub(ji) ) |
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| 298 | ! update precipitations after sublimation and correct sublimation |
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| 299 | zdh_s_pre(ji) = zdh_s_pre(ji) + zdeltah(ji,1) |
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| 300 | zdh_s_sub(ji) = zdh_s_sub(ji) - zdeltah(ji,1) |
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[1572] | 301 | END DO |
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| 302 | ENDIF |
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[825] | 303 | |
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[4688] | 304 | ! --- Update snow diags --- ! |
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[825] | 305 | DO ji = kideb, kiut |
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[5350] | 306 | dh_s_tot(ji) = zdh_s_mel(ji) + zdh_s_pre(ji) + zdh_s_sub(ji) |
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| 307 | END DO |
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[825] | 308 | |
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[4688] | 309 | !------------------------------------------- |
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| 310 | ! 3.3 Update temperature, energy |
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| 311 | !------------------------------------------- |
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| 312 | ! new temp and enthalpy of the snow (remaining snow precip + remaining pre-existing snow) |
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| 313 | zq_s(:) = 0._wp |
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[825] | 314 | DO jk = 1, nlay_s |
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| 315 | DO ji = kideb,kiut |
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[5134] | 316 | rswitch = MAX( 0._wp , SIGN( 1._wp, ht_s_1d(ji) - epsi20 ) ) |
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| 317 | q_s_1d(ji,jk) = rswitch / MAX( ht_s_1d(ji), epsi20 ) * & |
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[5350] | 318 | & ( ( zdh_s_pre(ji) ) * zqprec(ji) + & |
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| 319 | & ( ht_s_1d(ji) - zdh_s_pre(ji) ) * rhosn * ( cpic * ( rt0 - t_s_1d(ji,jk) ) + lfus ) ) |
---|
[4872] | 320 | zq_s(ji) = zq_s(ji) + q_s_1d(ji,jk) |
---|
[825] | 321 | END DO |
---|
| 322 | END DO |
---|
| 323 | |
---|
[4688] | 324 | !-------------------------- |
---|
| 325 | ! 3.4 Surface ice ablation |
---|
| 326 | !-------------------------- |
---|
| 327 | zdeltah(:,:) = 0._wp ! important |
---|
| 328 | DO jk = 1, nlay_i |
---|
[5350] | 329 | DO ji = kideb, kiut |
---|
| 330 | ztmelts = - tmut * s_i_1d(ji,jk) + rt0 ! Melting point of layer k [K] |
---|
| 331 | |
---|
| 332 | IF( t_i_1d(ji,jk) >= ztmelts ) THEN !!! Internal melting |
---|
[4688] | 333 | |
---|
[5350] | 334 | zEi = - q_i_1d(ji,jk) * r1_rhoic ! Specific enthalpy of layer k [J/kg, <0] |
---|
| 335 | zdE = 0._wp ! Specific enthalpy difference (J/kg, <0) |
---|
| 336 | ! set up at 0 since no energy is needed to melt water...(it is already melted) |
---|
| 337 | zdeltah(ji,jk) = MIN( 0._wp , - zh_i(ji,jk) ) ! internal melting occurs when the internal temperature is above freezing |
---|
| 338 | ! this should normally not happen, but sometimes, heat diffusion leads to this |
---|
| 339 | zfmdt = - zdeltah(ji,jk) * rhoic ! Mass flux x time step > 0 |
---|
| 340 | |
---|
| 341 | dh_i_surf(ji) = dh_i_surf(ji) + zdeltah(ji,jk) ! Cumulate surface melt |
---|
| 342 | |
---|
| 343 | zfmdt = - rhoic * zdeltah(ji,jk) ! Recompute mass flux [kg/m2, >0] |
---|
[4688] | 344 | |
---|
[5350] | 345 | ! Contribution to heat flux to the ocean [W.m-2], <0 (ice enthalpy zEi is "sent" to the ocean) |
---|
| 346 | hfx_res_1d(ji) = hfx_res_1d(ji) + zfmdt * a_i_1d(ji) * zEi * r1_rdtice |
---|
| 347 | |
---|
| 348 | ! Contribution to salt flux (clem: using sm_i_1d and not s_i_1d(jk) is ok) |
---|
| 349 | sfx_res_1d(ji) = sfx_res_1d(ji) - rhoic * a_i_1d(ji) * zdeltah(ji,jk) * sm_i_1d(ji) * r1_rdtice |
---|
| 350 | |
---|
| 351 | ! Contribution to mass flux |
---|
| 352 | wfx_res_1d(ji) = wfx_res_1d(ji) - rhoic * a_i_1d(ji) * zdeltah(ji,jk) * r1_rdtice |
---|
[4688] | 353 | |
---|
[5350] | 354 | ELSE !!! Surface melting |
---|
| 355 | |
---|
| 356 | zEi = - q_i_1d(ji,jk) * r1_rhoic ! Specific enthalpy of layer k [J/kg, <0] |
---|
| 357 | zEw = rcp * ( ztmelts - rt0 ) ! Specific enthalpy of resulting meltwater [J/kg, <0] |
---|
| 358 | zdE = zEi - zEw ! Specific enthalpy difference < 0 |
---|
| 359 | |
---|
| 360 | zfmdt = - zq_su(ji) / zdE ! Mass flux to the ocean [kg/m2, >0] |
---|
| 361 | |
---|
| 362 | zdeltah(ji,jk) = - zfmdt * r1_rhoic ! Melt of layer jk [m, <0] |
---|
| 363 | |
---|
| 364 | zdeltah(ji,jk) = MIN( 0._wp , MAX( zdeltah(ji,jk) , - zh_i(ji,jk) ) ) ! Melt of layer jk cannot exceed the layer thickness [m, <0] |
---|
| 365 | |
---|
| 366 | zq_su(ji) = MAX( 0._wp , zq_su(ji) - zdeltah(ji,jk) * rhoic * zdE ) ! update available heat |
---|
| 367 | |
---|
| 368 | dh_i_surf(ji) = dh_i_surf(ji) + zdeltah(ji,jk) ! Cumulate surface melt |
---|
| 369 | |
---|
| 370 | zfmdt = - rhoic * zdeltah(ji,jk) ! Recompute mass flux [kg/m2, >0] |
---|
| 371 | |
---|
| 372 | zQm = zfmdt * zEw ! Energy of the melt water sent to the ocean [J/m2, <0] |
---|
| 373 | |
---|
| 374 | ! Contribution to salt flux (clem: using sm_i_1d and not s_i_1d(jk) is ok) |
---|
| 375 | sfx_sum_1d(ji) = sfx_sum_1d(ji) - rhoic * a_i_1d(ji) * zdeltah(ji,jk) * sm_i_1d(ji) * r1_rdtice |
---|
| 376 | |
---|
| 377 | ! Contribution to heat flux [W.m-2], < 0 |
---|
| 378 | hfx_thd_1d(ji) = hfx_thd_1d(ji) + zfmdt * a_i_1d(ji) * zEw * r1_rdtice |
---|
| 379 | |
---|
| 380 | ! Total heat flux used in this process [W.m-2], > 0 |
---|
| 381 | hfx_sum_1d(ji) = hfx_sum_1d(ji) - zfmdt * a_i_1d(ji) * zdE * r1_rdtice |
---|
| 382 | |
---|
| 383 | ! Contribution to mass flux |
---|
| 384 | wfx_sum_1d(ji) = wfx_sum_1d(ji) - rhoic * a_i_1d(ji) * zdeltah(ji,jk) * r1_rdtice |
---|
| 385 | |
---|
| 386 | END IF |
---|
[4688] | 387 | ! record which layers have disappeared (for bottom melting) |
---|
| 388 | ! => icount=0 : no layer has vanished |
---|
| 389 | ! => icount=5 : 5 layers have vanished |
---|
[5350] | 390 | rswitch = MAX( 0._wp , SIGN( 1._wp , - ( zh_i(ji,jk) + zdeltah(ji,jk) ) ) ) |
---|
| 391 | icount(ji,jk) = NINT( rswitch ) |
---|
| 392 | zh_i(ji,jk) = MAX( 0._wp , zh_i(ji,jk) + zdeltah(ji,jk) ) |
---|
[4688] | 393 | |
---|
| 394 | ! update heat content (J.m-2) and layer thickness |
---|
[4872] | 395 | qh_i_old(ji,jk) = qh_i_old(ji,jk) + zdeltah(ji,jk) * q_i_1d(ji,jk) |
---|
[4688] | 396 | h_i_old (ji,jk) = h_i_old (ji,jk) + zdeltah(ji,jk) |
---|
[825] | 397 | END DO |
---|
[921] | 398 | END DO |
---|
[4688] | 399 | ! update ice thickness |
---|
| 400 | DO ji = kideb, kiut |
---|
[4872] | 401 | ht_i_1d(ji) = MAX( 0._wp , ht_i_1d(ji) + dh_i_surf(ji) ) |
---|
[4688] | 402 | END DO |
---|
[825] | 403 | |
---|
[921] | 404 | ! |
---|
| 405 | !------------------------------------------------------------------------------! |
---|
| 406 | ! 4) Basal growth / melt ! |
---|
| 407 | !------------------------------------------------------------------------------! |
---|
| 408 | ! |
---|
[4688] | 409 | !------------------ |
---|
| 410 | ! 4.1 Basal growth |
---|
| 411 | !------------------ |
---|
| 412 | ! Basal growth is driven by heat imbalance at the ice-ocean interface, |
---|
| 413 | ! between the inner conductive flux (fc_bo_i), from the open water heat flux |
---|
| 414 | ! (fhld) and the turbulent ocean flux (fhtur). |
---|
| 415 | ! fc_bo_i is positive downwards. fhtur and fhld are positive to the ice |
---|
[825] | 416 | |
---|
[4688] | 417 | ! If salinity varies in time, an iterative procedure is required, because |
---|
| 418 | ! the involved quantities are inter-dependent. |
---|
| 419 | ! Basal growth (dh_i_bott) depends upon new ice specific enthalpy (zEi), |
---|
| 420 | ! which depends on forming ice salinity (s_i_new), which depends on dh/dt (dh_i_bott) |
---|
| 421 | ! -> need for an iterative procedure, which converges quickly |
---|
| 422 | |
---|
[5350] | 423 | num_iter_max = 1 |
---|
| 424 | IF( nn_icesal == 2 ) num_iter_max = 5 |
---|
[825] | 425 | |
---|
[4688] | 426 | ! Iterative procedure |
---|
| 427 | DO iter = 1, num_iter_max |
---|
| 428 | DO ji = kideb, kiut |
---|
| 429 | IF( zf_tt(ji) < 0._wp ) THEN |
---|
[825] | 430 | |
---|
[4688] | 431 | ! New bottom ice salinity (Cox & Weeks, JGR88 ) |
---|
| 432 | !--- zswi1 if dh/dt < 2.0e-8 |
---|
| 433 | !--- zswi12 if 2.0e-8 < dh/dt < 3.6e-7 |
---|
| 434 | !--- zswi2 if dh/dt > 3.6e-7 |
---|
| 435 | zgrr = MIN( 1.0e-3, MAX ( dh_i_bott(ji) * r1_rdtice , epsi10 ) ) |
---|
| 436 | zswi2 = MAX( 0._wp , SIGN( 1._wp , zgrr - 3.6e-7 ) ) |
---|
| 437 | zswi12 = MAX( 0._wp , SIGN( 1._wp , zgrr - 2.0e-8 ) ) * ( 1.0 - zswi2 ) |
---|
| 438 | zswi1 = 1. - zswi2 * zswi12 |
---|
| 439 | zfracs = MIN ( zswi1 * 0.12 + zswi12 * ( 0.8925 + 0.0568 * LOG( 100.0 * zgrr ) ) & |
---|
| 440 | & + zswi2 * 0.26 / ( 0.26 + 0.74 * EXP ( - 724300.0 * zgrr ) ) , 0.5 ) |
---|
[825] | 441 | |
---|
[4688] | 442 | ii = MOD( npb(ji) - 1, jpi ) + 1 ; ij = ( npb(ji) - 1 ) / jpi + 1 |
---|
[825] | 443 | |
---|
[4688] | 444 | s_i_new(ji) = zswitch_sal * zfracs * sss_m(ii,ij) & ! New ice salinity |
---|
[4872] | 445 | + ( 1. - zswitch_sal ) * sm_i_1d(ji) |
---|
[4688] | 446 | ! New ice growth |
---|
[5123] | 447 | ztmelts = - tmut * s_i_new(ji) + rt0 ! New ice melting point (K) |
---|
[825] | 448 | |
---|
[4872] | 449 | zt_i_new = zswitch_sal * t_bo_1d(ji) + ( 1. - zswitch_sal) * t_i_1d(ji, nlay_i) |
---|
[4688] | 450 | |
---|
| 451 | zEi = cpic * ( zt_i_new - ztmelts ) & ! Specific enthalpy of forming ice (J/kg, <0) |
---|
[5123] | 452 | & - lfus * ( 1.0 - ( ztmelts - rt0 ) / ( zt_i_new - rt0 ) ) & |
---|
| 453 | & + rcp * ( ztmelts-rt0 ) |
---|
[4688] | 454 | |
---|
[4872] | 455 | zEw = rcp * ( t_bo_1d(ji) - rt0 ) ! Specific enthalpy of seawater (J/kg, < 0) |
---|
[4688] | 456 | |
---|
| 457 | zdE = zEi - zEw ! Specific enthalpy difference (J/kg, <0) |
---|
| 458 | |
---|
| 459 | dh_i_bott(ji) = rdt_ice * MAX( 0._wp , zf_tt(ji) / ( zdE * rhoic ) ) |
---|
| 460 | |
---|
[4872] | 461 | q_i_1d(ji,nlay_i+1) = -zEi * rhoic ! New ice energy of melting (J/m3, >0) |
---|
[4688] | 462 | |
---|
[5134] | 463 | ENDIF |
---|
| 464 | END DO |
---|
| 465 | END DO |
---|
[4688] | 466 | |
---|
| 467 | ! Contribution to Energy and Salt Fluxes |
---|
[825] | 468 | DO ji = kideb, kiut |
---|
[4688] | 469 | IF( zf_tt(ji) < 0._wp ) THEN |
---|
| 470 | ! New ice growth |
---|
| 471 | |
---|
| 472 | zfmdt = - rhoic * dh_i_bott(ji) ! Mass flux x time step (kg/m2, < 0) |
---|
| 473 | |
---|
[5123] | 474 | ztmelts = - tmut * s_i_new(ji) + rt0 ! New ice melting point (K) |
---|
[4688] | 475 | |
---|
[4872] | 476 | zt_i_new = zswitch_sal * t_bo_1d(ji) + ( 1. - zswitch_sal) * t_i_1d(ji, nlay_i) |
---|
[4688] | 477 | |
---|
| 478 | zEi = cpic * ( zt_i_new - ztmelts ) & ! Specific enthalpy of forming ice (J/kg, <0) |
---|
[5123] | 479 | & - lfus * ( 1.0 - ( ztmelts - rt0 ) / ( zt_i_new - rt0 ) ) & |
---|
| 480 | & + rcp * ( ztmelts-rt0 ) |
---|
[4688] | 481 | |
---|
[4872] | 482 | zEw = rcp * ( t_bo_1d(ji) - rt0 ) ! Specific enthalpy of seawater (J/kg, < 0) |
---|
[4688] | 483 | |
---|
| 484 | zdE = zEi - zEw ! Specific enthalpy difference (J/kg, <0) |
---|
| 485 | |
---|
| 486 | ! Contribution to heat flux to the ocean [W.m-2], >0 |
---|
[4872] | 487 | hfx_thd_1d(ji) = hfx_thd_1d(ji) + zfmdt * a_i_1d(ji) * zEw * r1_rdtice |
---|
[4688] | 488 | |
---|
| 489 | ! Total heat flux used in this process [W.m-2], <0 |
---|
[4872] | 490 | hfx_bog_1d(ji) = hfx_bog_1d(ji) - zfmdt * a_i_1d(ji) * zdE * r1_rdtice |
---|
[4688] | 491 | |
---|
| 492 | ! Contribution to salt flux, <0 |
---|
[5350] | 493 | sfx_bog_1d(ji) = sfx_bog_1d(ji) - rhoic * a_i_1d(ji) * dh_i_bott(ji) * s_i_new(ji) * r1_rdtice |
---|
[4688] | 494 | |
---|
| 495 | ! Contribution to mass flux, <0 |
---|
[4872] | 496 | wfx_bog_1d(ji) = wfx_bog_1d(ji) - rhoic * a_i_1d(ji) * dh_i_bott(ji) * r1_rdtice |
---|
[4688] | 497 | |
---|
| 498 | ! update heat content (J.m-2) and layer thickness |
---|
[4872] | 499 | qh_i_old(ji,nlay_i+1) = qh_i_old(ji,nlay_i+1) + dh_i_bott(ji) * q_i_1d(ji,nlay_i+1) |
---|
[4688] | 500 | h_i_old (ji,nlay_i+1) = h_i_old (ji,nlay_i+1) + dh_i_bott(ji) |
---|
[825] | 501 | ENDIF |
---|
| 502 | END DO |
---|
| 503 | |
---|
[4688] | 504 | !---------------- |
---|
| 505 | ! 4.2 Basal melt |
---|
| 506 | !---------------- |
---|
| 507 | zdeltah(:,:) = 0._wp ! important |
---|
[825] | 508 | DO jk = nlay_i, 1, -1 |
---|
| 509 | DO ji = kideb, kiut |
---|
[5350] | 510 | IF( zf_tt(ji) > 0._wp .AND. jk > icount(ji,jk) ) THEN ! do not calculate where layer has already disappeared by surface melting |
---|
[825] | 511 | |
---|
[5123] | 512 | ztmelts = - tmut * s_i_1d(ji,jk) + rt0 ! Melting point of layer jk (K) |
---|
[825] | 513 | |
---|
[4872] | 514 | IF( t_i_1d(ji,jk) >= ztmelts ) THEN !!! Internal melting |
---|
[825] | 515 | |
---|
[5123] | 516 | zEi = - q_i_1d(ji,jk) * r1_rhoic ! Specific enthalpy of melting ice (J/kg, <0) |
---|
[4688] | 517 | zdE = 0._wp ! Specific enthalpy difference (J/kg, <0) |
---|
| 518 | ! set up at 0 since no energy is needed to melt water...(it is already melted) |
---|
[5350] | 519 | zdeltah (ji,jk) = MIN( 0._wp , - zh_i(ji,jk) ) ! internal melting occurs when the internal temperature is above freezing |
---|
| 520 | ! this should normally not happen, but sometimes, heat diffusion leads to this |
---|
[4161] | 521 | |
---|
[4688] | 522 | dh_i_bott (ji) = dh_i_bott(ji) + zdeltah(ji,jk) |
---|
[825] | 523 | |
---|
[5350] | 524 | zfmdt = - zdeltah(ji,jk) * rhoic ! Mass flux x time step > 0 |
---|
[825] | 525 | |
---|
[4688] | 526 | ! Contribution to heat flux to the ocean [W.m-2], <0 (ice enthalpy zEi is "sent" to the ocean) |
---|
[4872] | 527 | hfx_res_1d(ji) = hfx_res_1d(ji) + zfmdt * a_i_1d(ji) * zEi * r1_rdtice |
---|
[825] | 528 | |
---|
[4872] | 529 | ! Contribution to salt flux (clem: using sm_i_1d and not s_i_1d(jk) is ok) |
---|
[5350] | 530 | sfx_res_1d(ji) = sfx_res_1d(ji) - rhoic * a_i_1d(ji) * zdeltah(ji,jk) * sm_i_1d(ji) * r1_rdtice |
---|
[4688] | 531 | |
---|
| 532 | ! Contribution to mass flux |
---|
[4872] | 533 | wfx_res_1d(ji) = wfx_res_1d(ji) - rhoic * a_i_1d(ji) * zdeltah(ji,jk) * r1_rdtice |
---|
[825] | 534 | |
---|
[4688] | 535 | ! update heat content (J.m-2) and layer thickness |
---|
[4872] | 536 | qh_i_old(ji,jk) = qh_i_old(ji,jk) + zdeltah(ji,jk) * q_i_1d(ji,jk) |
---|
[4688] | 537 | h_i_old (ji,jk) = h_i_old (ji,jk) + zdeltah(ji,jk) |
---|
[825] | 538 | |
---|
[4688] | 539 | ELSE !!! Basal melting |
---|
[825] | 540 | |
---|
[5350] | 541 | zEi = - q_i_1d(ji,jk) * r1_rhoic ! Specific enthalpy of melting ice (J/kg, <0) |
---|
| 542 | zEw = rcp * ( ztmelts - rt0 ) ! Specific enthalpy of meltwater (J/kg, <0) |
---|
| 543 | zdE = zEi - zEw ! Specific enthalpy difference (J/kg, <0) |
---|
[825] | 544 | |
---|
[5350] | 545 | zfmdt = - zq_bo(ji) / zdE ! Mass flux x time step (kg/m2, >0) |
---|
[825] | 546 | |
---|
[5350] | 547 | zdeltah(ji,jk) = - zfmdt * r1_rhoic ! Gross thickness change |
---|
[4688] | 548 | |
---|
[5350] | 549 | zdeltah(ji,jk) = MIN( 0._wp , MAX( zdeltah(ji,jk), - zh_i(ji,jk) ) ) ! bound thickness change |
---|
[4688] | 550 | |
---|
[5350] | 551 | zq_bo(ji) = MAX( 0._wp , zq_bo(ji) - zdeltah(ji,jk) * rhoic * zdE ) ! update available heat. MAX is necessary for roundup errors |
---|
[4688] | 552 | |
---|
[5350] | 553 | dh_i_bott(ji) = dh_i_bott(ji) + zdeltah(ji,jk) ! Update basal melt |
---|
[4688] | 554 | |
---|
[5350] | 555 | zfmdt = - zdeltah(ji,jk) * rhoic ! Mass flux x time step > 0 |
---|
[4688] | 556 | |
---|
[5350] | 557 | zQm = zfmdt * zEw ! Heat exchanged with ocean |
---|
[4688] | 558 | |
---|
| 559 | ! Contribution to heat flux to the ocean [W.m-2], <0 |
---|
[5350] | 560 | hfx_thd_1d(ji) = hfx_thd_1d(ji) + zfmdt * a_i_1d(ji) * zEw * r1_rdtice |
---|
[4688] | 561 | |
---|
[4872] | 562 | ! Contribution to salt flux (clem: using sm_i_1d and not s_i_1d(jk) is ok) |
---|
[5350] | 563 | sfx_bom_1d(ji) = sfx_bom_1d(ji) - rhoic * a_i_1d(ji) * zdeltah(ji,jk) * sm_i_1d(ji) * r1_rdtice |
---|
[4688] | 564 | |
---|
| 565 | ! Total heat flux used in this process [W.m-2], >0 |
---|
[5350] | 566 | hfx_bom_1d(ji) = hfx_bom_1d(ji) - zfmdt * a_i_1d(ji) * zdE * r1_rdtice |
---|
[4688] | 567 | |
---|
| 568 | ! Contribution to mass flux |
---|
[5350] | 569 | wfx_bom_1d(ji) = wfx_bom_1d(ji) - rhoic * a_i_1d(ji) * zdeltah(ji,jk) * r1_rdtice |
---|
[4688] | 570 | |
---|
| 571 | ! update heat content (J.m-2) and layer thickness |
---|
[4872] | 572 | qh_i_old(ji,jk) = qh_i_old(ji,jk) + zdeltah(ji,jk) * q_i_1d(ji,jk) |
---|
[4688] | 573 | h_i_old (ji,jk) = h_i_old (ji,jk) + zdeltah(ji,jk) |
---|
| 574 | ENDIF |
---|
| 575 | |
---|
| 576 | ENDIF |
---|
[5123] | 577 | END DO |
---|
| 578 | END DO |
---|
[4688] | 579 | |
---|
[825] | 580 | !------------------------------------------- |
---|
[4688] | 581 | ! Update temperature, energy |
---|
[825] | 582 | !------------------------------------------- |
---|
| 583 | DO ji = kideb, kiut |
---|
[4872] | 584 | ht_i_1d(ji) = MAX( 0._wp , ht_i_1d(ji) + dh_i_bott(ji) ) |
---|
[4688] | 585 | END DO |
---|
[825] | 586 | |
---|
[4688] | 587 | !------------------------------------------- |
---|
| 588 | ! 5. What to do with remaining energy |
---|
| 589 | !------------------------------------------- |
---|
| 590 | ! If heat still available for melting and snow remains, then melt more snow |
---|
| 591 | !------------------------------------------- |
---|
| 592 | zdeltah(:,:) = 0._wp ! important |
---|
| 593 | DO ji = kideb, kiut |
---|
| 594 | zq_rema(ji) = zq_su(ji) + zq_bo(ji) |
---|
[5128] | 595 | rswitch = 1._wp - MAX( 0._wp, SIGN( 1._wp, - ht_s_1d(ji) ) ) ! =1 if snow |
---|
[5134] | 596 | rswitch = rswitch * MAX( 0._wp, SIGN( 1._wp, q_s_1d(ji,1) - epsi20 ) ) |
---|
| 597 | zdeltah (ji,1) = - rswitch * zq_rema(ji) / MAX( q_s_1d(ji,1), epsi20 ) |
---|
[5128] | 598 | zdeltah (ji,1) = MIN( 0._wp , MAX( zdeltah(ji,1) , - ht_s_1d(ji) ) ) ! bound melting |
---|
| 599 | dh_s_tot (ji) = dh_s_tot(ji) + zdeltah(ji,1) |
---|
| 600 | ht_s_1d (ji) = ht_s_1d(ji) + zdeltah(ji,1) |
---|
| 601 | |
---|
[5134] | 602 | zq_rema(ji) = zq_rema(ji) + zdeltah(ji,1) * q_s_1d(ji,1) ! update available heat (J.m-2) |
---|
[5128] | 603 | ! heat used to melt snow |
---|
[5134] | 604 | hfx_snw_1d(ji) = hfx_snw_1d(ji) - zdeltah(ji,1) * a_i_1d(ji) * q_s_1d(ji,1) * r1_rdtice ! W.m-2 (>0) |
---|
[5128] | 605 | ! Contribution to mass flux |
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| 606 | wfx_snw_1d(ji) = wfx_snw_1d(ji) - rhosn * a_i_1d(ji) * zdeltah(ji,1) * r1_rdtice |
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| 607 | ! |
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[4688] | 608 | ii = MOD( npb(ji) - 1, jpi ) + 1 ; ij = ( npb(ji) - 1 ) / jpi + 1 |
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| 609 | ! Remaining heat flux (W.m-2) is sent to the ocean heat budget |
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[5123] | 610 | hfx_out(ii,ij) = hfx_out(ii,ij) + ( zq_rema(ji) * a_i_1d(ji) ) * r1_rdtice |
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[825] | 611 | |
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[5128] | 612 | IF( ln_icectl .AND. zq_rema(ji) < 0. .AND. lwp ) WRITE(numout,*) 'ALERTE zq_rema <0 = ', zq_rema(ji) |
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[4688] | 613 | END DO |
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| 614 | |
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[921] | 615 | ! |
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| 616 | !------------------------------------------------------------------------------| |
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| 617 | ! 6) Snow-Ice formation | |
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| 618 | !------------------------------------------------------------------------------| |
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[1572] | 619 | ! When snow load excesses Archimede's limit, snow-ice interface goes down under sea-level, |
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| 620 | ! flooding of seawater transforms snow into ice dh_snowice is positive for the ice |
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[825] | 621 | DO ji = kideb, kiut |
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[1572] | 622 | ! |
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[4872] | 623 | dh_snowice(ji) = MAX( 0._wp , ( rhosn * ht_s_1d(ji) + (rhoic-rau0) * ht_i_1d(ji) ) / ( rhosn+rau0-rhoic ) ) |
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[825] | 624 | |
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[5350] | 625 | ht_i_1d(ji) = ht_i_1d(ji) + dh_snowice(ji) |
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| 626 | ht_s_1d(ji) = ht_s_1d(ji) - dh_snowice(ji) |
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[825] | 627 | |
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[4688] | 628 | ! Salinity of snow ice |
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| 629 | ii = MOD( npb(ji) - 1, jpi ) + 1 ; ij = ( npb(ji) - 1 ) / jpi + 1 |
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[5123] | 630 | zs_snic = zswitch_sal * sss_m(ii,ij) * ( rhoic - rhosn ) * r1_rhoic + ( 1. - zswitch_sal ) * sm_i_1d(ji) |
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[825] | 631 | |
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| 632 | ! entrapment during snow ice formation |
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[5134] | 633 | ! new salinity difference stored (to be used in limthd_sal.F90) |
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[5123] | 634 | IF ( nn_icesal == 2 ) THEN |
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[5134] | 635 | rswitch = MAX( 0._wp , SIGN( 1._wp , ht_i_1d(ji) - epsi20 ) ) |
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[4161] | 636 | ! salinity dif due to snow-ice formation |
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[5134] | 637 | dsm_i_si_1d(ji) = ( zs_snic - sm_i_1d(ji) ) * dh_snowice(ji) / MAX( ht_i_1d(ji), epsi20 ) * rswitch |
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[4161] | 638 | ! salinity dif due to bottom growth |
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[4688] | 639 | IF ( zf_tt(ji) < 0._wp ) THEN |
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[5134] | 640 | dsm_i_se_1d(ji) = ( s_i_new(ji) - sm_i_1d(ji) ) * dh_i_bott(ji) / MAX( ht_i_1d(ji), epsi20 ) * rswitch |
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[4161] | 641 | ENDIF |
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| 642 | ENDIF |
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[825] | 643 | |
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[4688] | 644 | ! Contribution to energy flux to the ocean [J/m2], >0 (if sst<0) |
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| 645 | ii = MOD( npb(ji) - 1, jpi ) + 1 ; ij = ( npb(ji) - 1 ) / jpi + 1 |
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| 646 | zfmdt = ( rhosn - rhoic ) * MAX( dh_snowice(ji), 0._wp ) ! <0 |
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| 647 | zsstK = sst_m(ii,ij) + rt0 |
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| 648 | zEw = rcp * ( zsstK - rt0 ) |
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| 649 | zQm = zfmdt * zEw |
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| 650 | |
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| 651 | ! Contribution to heat flux |
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[4872] | 652 | hfx_thd_1d(ji) = hfx_thd_1d(ji) + zfmdt * a_i_1d(ji) * zEw * r1_rdtice |
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[825] | 653 | |
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[4688] | 654 | ! Contribution to salt flux |
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[4872] | 655 | sfx_sni_1d(ji) = sfx_sni_1d(ji) + sss_m(ii,ij) * a_i_1d(ji) * zfmdt * r1_rdtice |
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[4688] | 656 | |
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| 657 | ! Contribution to mass flux |
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| 658 | ! All snow is thrown in the ocean, and seawater is taken to replace the volume |
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[4872] | 659 | wfx_sni_1d(ji) = wfx_sni_1d(ji) - a_i_1d(ji) * dh_snowice(ji) * rhoic * r1_rdtice |
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| 660 | wfx_snw_1d(ji) = wfx_snw_1d(ji) + a_i_1d(ji) * dh_snowice(ji) * rhosn * r1_rdtice |
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[4688] | 661 | |
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| 662 | ! update heat content (J.m-2) and layer thickness |
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[4872] | 663 | qh_i_old(ji,0) = qh_i_old(ji,0) + dh_snowice(ji) * q_s_1d(ji,1) + zfmdt * zEw |
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[4688] | 664 | h_i_old (ji,0) = h_i_old (ji,0) + dh_snowice(ji) |
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| 665 | |
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[5134] | 666 | END DO |
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[825] | 667 | |
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[2715] | 668 | ! |
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[4688] | 669 | !------------------------------------------- |
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| 670 | ! Update temperature, energy |
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| 671 | !------------------------------------------- |
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| 672 | DO ji = kideb, kiut |
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[4990] | 673 | rswitch = 1.0 - MAX( 0._wp , SIGN( 1._wp , - ht_i_1d(ji) ) ) |
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[5123] | 674 | t_su_1d(ji) = rswitch * t_su_1d(ji) + ( 1.0 - rswitch ) * rt0 |
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[5134] | 675 | END DO |
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[4688] | 676 | |
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| 677 | DO jk = 1, nlay_s |
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| 678 | DO ji = kideb,kiut |
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| 679 | ! mask enthalpy |
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[5134] | 680 | rswitch = 1._wp - MAX( 0._wp , SIGN( 1._wp, - ht_s_1d(ji) ) ) |
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| 681 | q_s_1d(ji,jk) = rswitch * q_s_1d(ji,jk) |
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[4872] | 682 | ! recalculate t_s_1d from q_s_1d |
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[5134] | 683 | t_s_1d(ji,jk) = rt0 + rswitch * ( - q_s_1d(ji,jk) / ( rhosn * cpic ) + lfus / cpic ) |
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[4688] | 684 | END DO |
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| 685 | END DO |
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[5134] | 686 | |
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| 687 | ! --- ensure that a_i = 0 where ht_i = 0 --- |
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| 688 | WHERE( ht_i_1d == 0._wp ) a_i_1d = 0._wp |
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[5123] | 689 | |
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[5350] | 690 | CALL wrk_dealloc( jpij, zqprec, zq_su, zq_bo, zf_tt, zq_rema ) |
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[4688] | 691 | CALL wrk_dealloc( jpij, zdh_s_mel, zdh_s_pre, zdh_s_sub, zqh_i, zqh_s, zq_s ) |
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[5350] | 692 | CALL wrk_dealloc( jpij, nlay_i, zdeltah, zh_i ) |
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| 693 | CALL wrk_dealloc( jpij, nlay_i, icount ) |
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[2715] | 694 | ! |
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[4161] | 695 | ! |
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[921] | 696 | END SUBROUTINE lim_thd_dh |
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[1572] | 697 | |
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[825] | 698 | #else |
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[1572] | 699 | !!---------------------------------------------------------------------- |
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| 700 | !! Default option NO LIM3 sea-ice model |
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| 701 | !!---------------------------------------------------------------------- |
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[825] | 702 | CONTAINS |
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| 703 | SUBROUTINE lim_thd_dh ! Empty routine |
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| 704 | END SUBROUTINE lim_thd_dh |
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| 705 | #endif |
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[1572] | 706 | |
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| 707 | !!====================================================================== |
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[921] | 708 | END MODULE limthd_dh |
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