[3] | 1 | MODULE trazdf_exp |
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| 2 | !!============================================================================== |
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| 3 | !! *** MODULE trazdf_exp *** |
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| 4 | !! Ocean active tracers: vertical component of the tracer mixing trend using |
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| 5 | !! an explicit time-stepping (time spllitting scheme) |
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| 6 | !!============================================================================== |
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| 7 | |
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| 8 | !!---------------------------------------------------------------------- |
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| 9 | !! tra_zdf_exp : update the tracer trend with the vertical diffusion |
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| 10 | !! using an explicit time stepping |
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| 11 | !!---------------------------------------------------------------------- |
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| 12 | !! * Modules used |
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| 13 | USE oce ! ocean dynamics and active tracers |
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| 14 | USE dom_oce ! ocean space and time domain |
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[216] | 15 | USE trdmod ! ocean active tracers trends |
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| 16 | USE trdmod_oce ! ocean variables trends |
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[3] | 17 | USE zdf_oce ! ocean vertical physics |
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| 18 | USE zdfddm ! ocean vertical physics: double diffusion |
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| 19 | USE in_out_manager ! I/O manager |
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| 20 | |
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| 21 | IMPLICIT NONE |
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| 22 | PRIVATE |
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| 23 | |
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| 24 | !! * Routine accessibility |
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| 25 | PUBLIC tra_zdf_exp ! routine called by step.F90 |
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| 26 | |
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| 27 | !! * Module variable |
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| 28 | REAL(wp), DIMENSION(jpk) :: & |
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| 29 | r2dt ! vertical profile of 2 x tracer time-step |
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| 30 | |
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| 31 | !! * Substitutions |
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| 32 | # include "domzgr_substitute.h90" |
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| 33 | # include "zdfddm_substitute.h90" |
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| 34 | !!---------------------------------------------------------------------- |
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[247] | 35 | !! OPA 9.0 , LOCEAN-IPSL (2005) |
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| 36 | !! $Header$ |
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| 37 | !! This software is governed by the CeCILL licence see modipsl/doc/NEMO_CeCILL.txt |
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[3] | 38 | !!---------------------------------------------------------------------- |
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| 39 | |
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| 40 | CONTAINS |
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| 41 | |
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| 42 | SUBROUTINE tra_zdf_exp( kt ) |
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| 43 | !!---------------------------------------------------------------------- |
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| 44 | !! *** ROUTINE tra_zdf_exp *** |
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| 45 | !! |
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| 46 | !! ** Purpose : Compute the trend due to the vertical tracer mixing |
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| 47 | !! using an explicit time stepping and add it to the general trend |
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| 48 | !! of the tracer equations. |
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| 49 | !! |
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| 50 | !! ** Method : The vertical diffusion of tracers (t & s) is given by: |
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| 51 | !! difft = dz( avt dz(tb) ) = 1/e3t dk+1( avt/e3w dk(tb) ) |
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| 52 | !! It is evaluated with an Euler scheme, using a time splitting |
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| 53 | !! technique. |
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| 54 | !! Surface and bottom boundary conditions: no diffusive flux on |
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| 55 | !! both tracers (bottom, applied through the masked field avt). |
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| 56 | !! Add this trend to the general trend ta,sa : |
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| 57 | !! ta = ta + dz( avt dz(t) ) |
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| 58 | !! (sa = sa + dz( avs dz(t) ) if lk_zdfddm= T) |
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| 59 | !! |
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| 60 | !! ** Action : - Update (ta,sa) with the before vertical diffusion trend |
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[216] | 61 | !! - Save the trends in (ztdta,ztdsa) ('key_trdtra') |
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[3] | 62 | !! |
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| 63 | !! History : |
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| 64 | !! 6.0 ! 90-10 (B. Blanke) Original code |
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| 65 | !! 7.0 ! 91-11 (G. Madec) |
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| 66 | !! ! 92-06 (M. Imbard) correction on tracer trend loops |
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| 67 | !! ! 96-01 (G. Madec) statement function for e3 |
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| 68 | !! ! 97-05 (G. Madec) vertical component of isopycnal |
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| 69 | !! ! 97-07 (G. Madec) geopotential diffusion in s-coord |
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| 70 | !! ! 00-08 (G. Madec) double diffusive mixing |
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| 71 | !! 8.5 ! 02-08 (G. Madec) F90: Free form and module |
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[216] | 72 | !! 9.0 ! 04-08 (C. Talandier) New trends organization |
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[3] | 73 | !!--------------------------------------------------------------------- |
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[216] | 74 | !! * Modules used |
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| 75 | USE oce, ONLY : ztdta => ua, & ! use ua as 3D workspace |
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| 76 | ztdsa => va ! use va as 3D workspace |
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| 77 | |
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[3] | 78 | !! * Arguments |
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| 79 | INTEGER, INTENT( in ) :: kt ! ocean time-step index |
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| 80 | |
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| 81 | !! * Local declarations |
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| 82 | INTEGER :: ji, jj, jk, jl ! dummy loop indices |
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| 83 | REAL(wp) :: & |
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[216] | 84 | zlavmr, & ! temporary scalars |
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| 85 | zave3r, ze3tr, & ! " " |
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| 86 | zta, zsa ! " " |
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[3] | 87 | REAL(wp), DIMENSION(jpi,jpk) :: & |
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| 88 | zwx, zwy, zwz, zww |
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| 89 | !!--------------------------------------------------------------------- |
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| 90 | |
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| 91 | |
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| 92 | ! 0. Local constant initialization |
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| 93 | ! -------------------------------- |
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| 94 | ! time step = 2 rdttra |
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| 95 | IF( neuler == 0 .AND. kt == nit000 ) THEN |
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| 96 | r2dt(:) = rdttra(:) ! restarting with Euler time stepping |
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| 97 | ELSEIF( kt <= nit000 + 1) THEN |
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| 98 | r2dt(:) = 2. * rdttra(:) ! leapfrog |
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| 99 | ENDIF |
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| 100 | zlavmr = 1. / float( n_zdfexp ) |
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| 101 | |
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[216] | 102 | ! Save ta and sa trends |
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| 103 | IF( l_trdtra ) THEN |
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| 104 | ztdta(:,:,:) = ta(:,:,:) |
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| 105 | ztdsa(:,:,:) = sa(:,:,:) |
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| 106 | ENDIF |
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| 107 | |
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[3] | 108 | ! ! =============== |
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| 109 | DO jj = 2, jpjm1 ! Vertical slab |
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| 110 | ! ! =============== |
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| 111 | ! 1. Initializations |
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| 112 | ! ------------------ |
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| 113 | |
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| 114 | ! Surface & bottom boundary conditions: no flux |
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| 115 | DO ji = 2, jpim1 |
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| 116 | zwy(ji, 1 ) = 0.e0 |
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| 117 | zwy(ji,jpk) = 0.e0 |
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| 118 | zww(ji, 1 ) = 0.e0 |
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| 119 | zww(ji,jpk) = 0.e0 |
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| 120 | END DO |
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| 121 | |
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| 122 | ! zwx and zwz arrays set to before tracer values |
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| 123 | DO jk = 1, jpk |
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| 124 | DO ji = 2, jpim1 |
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| 125 | zwx(ji,jk) = tb(ji,jj,jk) |
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| 126 | zwz(ji,jk) = sb(ji,jj,jk) |
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| 127 | END DO |
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| 128 | END DO |
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| 129 | |
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| 130 | |
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| 131 | ! 2. Time splitting loop |
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| 132 | ! ---------------------- |
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| 133 | |
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| 134 | DO jl = 1, n_zdfexp |
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| 135 | |
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| 136 | ! first vertical derivative |
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| 137 | IF( lk_zdfddm ) THEN ! double diffusion: avs /= avt |
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| 138 | DO jk = 2, jpk |
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| 139 | DO ji = 2, jpim1 |
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| 140 | zave3r = 1.e0 / fse3w(ji,jj,jk) |
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| 141 | zwy(ji,jk) = avt(ji,jj,jk) * ( zwx(ji,jk-1) - zwx(ji,jk) ) * zave3r |
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| 142 | zww(ji,jk) = fsavs(ji,jj,jk) * ( zwz(ji,jk-1) - zwz(ji,jk) ) * zave3r |
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| 143 | END DO |
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| 144 | END DO |
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| 145 | ELSE ! default : avs = avt |
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| 146 | DO jk = 2, jpk |
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| 147 | DO ji = 2, jpim1 |
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| 148 | zave3r = avt(ji,jj,jk) / fse3w(ji,jj,jk) |
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| 149 | zwy(ji,jk) = zave3r *(zwx(ji,jk-1) - zwx(ji,jk) ) |
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| 150 | zww(ji,jk) = zave3r *(zwz(ji,jk-1) - zwz(ji,jk) ) |
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| 151 | END DO |
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| 152 | END DO |
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| 153 | ENDIF |
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| 154 | |
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| 155 | ! trend estimation at kt+l*2*rdt/n_zdfexp |
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| 156 | DO jk = 1, jpkm1 |
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| 157 | DO ji = 2, jpim1 |
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| 158 | ze3tr = zlavmr / fse3t(ji,jj,jk) |
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| 159 | ! 2nd vertical derivative |
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| 160 | zta = ( zwy(ji,jk) - zwy(ji,jk+1) ) * ze3tr |
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| 161 | zsa = ( zww(ji,jk) - zww(ji,jk+1) ) * ze3tr |
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| 162 | ! update the tracer trends |
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| 163 | ta(ji,jj,jk) = ta(ji,jj,jk) + zta |
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| 164 | sa(ji,jj,jk) = sa(ji,jj,jk) + zsa |
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| 165 | ! update tracer fields at kt+l*2*rdt/n_zdfexp |
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| 166 | zwx(ji,jk) = zwx(ji,jk) + r2dt(jk) * zta * tmask(ji,jj,jk) |
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| 167 | zwz(ji,jk) = zwz(ji,jk) + r2dt(jk) * zsa * tmask(ji,jj,jk) |
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| 168 | END DO |
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| 169 | END DO |
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| 170 | END DO |
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| 171 | ! ! =============== |
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| 172 | END DO ! End of slab |
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| 173 | ! ! =============== |
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[216] | 174 | ! save the trends for diagnostic |
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| 175 | ! vertical diffusive tracers trends |
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| 176 | IF( l_trdtra ) THEN |
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| 177 | ztdta(:,:,:) = ta(:,:,:) - ztdta(:,:,:) |
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| 178 | ztdsa(:,:,:) = sa(:,:,:) - ztdsa(:,:,:) |
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| 179 | CALL trd_mod(ztdta, ztdsa, jpttdzdf, 'TRA', kt) |
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| 180 | ENDIF |
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| 181 | |
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| 182 | IF(l_ctl) THEN ! print mean trends (used for debugging) |
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| 183 | zta = SUM( ta(2:nictl,2:njctl,1:jpkm1) * tmask(2:nictl,2:njctl,1:jpkm1) ) |
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| 184 | zsa = SUM( sa(2:nictl,2:njctl,1:jpkm1) * tmask(2:nictl,2:njctl,1:jpkm1) ) |
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| 185 | WRITE(numout,*) ' zdf - Ta: ', zta-t_ctl, ' Sa: ', zsa-s_ctl |
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| 186 | t_ctl = zta ; s_ctl = zsa |
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| 187 | ENDIF |
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| 188 | |
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[3] | 189 | END SUBROUTINE tra_zdf_exp |
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| 190 | |
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| 191 | !!============================================================================== |
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| 192 | END MODULE trazdf_exp |
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