[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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[457] | 7 | !! History : |
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| 8 | !! 6.0 ! 90-10 (B. Blanke) Original code |
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| 9 | !! 7.0 ! 91-11 (G. Madec) |
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| 10 | !! ! 92-06 (M. Imbard) correction on tracer trend loops |
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| 11 | !! ! 96-01 (G. Madec) statement function for e3 |
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| 12 | !! ! 97-05 (G. Madec) vertical component of isopycnal |
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| 13 | !! ! 97-07 (G. Madec) geopotential diffusion in s-coord |
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| 14 | !! ! 00-08 (G. Madec) double diffusive mixing |
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| 15 | !! 8.5 ! 02-08 (G. Madec) F90: Free form and module |
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| 16 | !! 9.0 ! 04-08 (C. Talandier) New trends organisation |
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| 17 | !! ! 05-11 (G. Madec) New organisation |
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[3] | 18 | !!---------------------------------------------------------------------- |
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| 19 | !! tra_zdf_exp : update the tracer trend with the vertical diffusion |
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| 20 | !! using an explicit time stepping |
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| 21 | !!---------------------------------------------------------------------- |
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| 22 | !! * Modules used |
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| 23 | USE oce ! ocean dynamics and active tracers |
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| 24 | USE dom_oce ! ocean space and time domain |
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[216] | 25 | USE trdmod ! ocean active tracers trends |
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| 26 | USE trdmod_oce ! ocean variables trends |
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[3] | 27 | USE zdf_oce ! ocean vertical physics |
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| 28 | USE zdfddm ! ocean vertical physics: double diffusion |
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| 29 | USE in_out_manager ! I/O manager |
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[258] | 30 | USE prtctl ! Print control |
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[3] | 31 | |
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| 32 | IMPLICIT NONE |
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| 33 | PRIVATE |
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| 34 | |
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| 35 | !! * Routine accessibility |
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| 36 | PUBLIC tra_zdf_exp ! routine called by step.F90 |
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| 37 | |
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| 38 | !! * Substitutions |
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| 39 | # include "domzgr_substitute.h90" |
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| 40 | # include "zdfddm_substitute.h90" |
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| 41 | !!---------------------------------------------------------------------- |
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[247] | 42 | !! OPA 9.0 , LOCEAN-IPSL (2005) |
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[699] | 43 | !! $Id$ |
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[247] | 44 | !! This software is governed by the CeCILL licence see modipsl/doc/NEMO_CeCILL.txt |
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[3] | 45 | !!---------------------------------------------------------------------- |
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| 46 | |
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| 47 | CONTAINS |
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| 48 | |
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[457] | 49 | SUBROUTINE tra_zdf_exp( kt, p2dt ) |
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[3] | 50 | !!---------------------------------------------------------------------- |
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| 51 | !! *** ROUTINE tra_zdf_exp *** |
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| 52 | !! |
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| 53 | !! ** Purpose : Compute the trend due to the vertical tracer mixing |
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| 54 | !! using an explicit time stepping and add it to the general trend |
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| 55 | !! of the tracer equations. |
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| 56 | !! |
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| 57 | !! ** Method : The vertical diffusion of tracers (t & s) is given by: |
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| 58 | !! difft = dz( avt dz(tb) ) = 1/e3t dk+1( avt/e3w dk(tb) ) |
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| 59 | !! It is evaluated with an Euler scheme, using a time splitting |
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| 60 | !! technique. |
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| 61 | !! Surface and bottom boundary conditions: no diffusive flux on |
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| 62 | !! both tracers (bottom, applied through the masked field avt). |
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| 63 | !! Add this trend to the general trend ta,sa : |
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| 64 | !! ta = ta + dz( avt dz(t) ) |
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| 65 | !! (sa = sa + dz( avs dz(t) ) if lk_zdfddm= T) |
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| 66 | !! |
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| 67 | !! ** Action : - Update (ta,sa) with the before vertical diffusion trend |
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| 68 | !! |
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| 69 | !!--------------------------------------------------------------------- |
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| 70 | !! * Arguments |
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| 71 | INTEGER, INTENT( in ) :: kt ! ocean time-step index |
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[457] | 72 | REAL(wp), DIMENSION(jpk), INTENT( in ) :: & |
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| 73 | p2dt ! vertical profile of tracer time-step |
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[3] | 74 | |
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| 75 | !! * Local declarations |
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| 76 | INTEGER :: ji, jj, jk, jl ! dummy loop indices |
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| 77 | REAL(wp) :: & |
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[216] | 78 | zlavmr, & ! temporary scalars |
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| 79 | zave3r, ze3tr, & ! " " |
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| 80 | zta, zsa ! " " |
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[3] | 81 | REAL(wp), DIMENSION(jpi,jpk) :: & |
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| 82 | zwx, zwy, zwz, zww |
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| 83 | !!--------------------------------------------------------------------- |
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| 84 | |
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[457] | 85 | IF( kt == nit000 ) THEN |
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| 86 | IF(lwp) WRITE(numout,*) |
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[811] | 87 | IF(lwp) WRITE(numout,*) 'tra_zdf_exp : explicit vertical mixing' |
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[457] | 88 | IF(lwp) WRITE(numout,*) '~~~~~~~~~~~' |
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| 89 | ENDIF |
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[3] | 90 | |
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[457] | 91 | |
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[3] | 92 | ! 0. Local constant initialization |
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| 93 | ! -------------------------------- |
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| 94 | zlavmr = 1. / float( n_zdfexp ) |
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| 95 | |
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| 96 | ! ! =============== |
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| 97 | DO jj = 2, jpjm1 ! Vertical slab |
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| 98 | ! ! =============== |
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| 99 | ! 1. Initializations |
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| 100 | ! ------------------ |
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| 101 | |
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| 102 | ! Surface & bottom boundary conditions: no flux |
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| 103 | DO ji = 2, jpim1 |
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| 104 | zwy(ji, 1 ) = 0.e0 |
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| 105 | zwy(ji,jpk) = 0.e0 |
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| 106 | zww(ji, 1 ) = 0.e0 |
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| 107 | zww(ji,jpk) = 0.e0 |
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| 108 | END DO |
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| 109 | |
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| 110 | ! zwx and zwz arrays set to before tracer values |
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| 111 | DO jk = 1, jpk |
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| 112 | DO ji = 2, jpim1 |
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| 113 | zwx(ji,jk) = tb(ji,jj,jk) |
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| 114 | zwz(ji,jk) = sb(ji,jj,jk) |
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| 115 | END DO |
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| 116 | END DO |
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| 117 | |
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| 118 | |
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| 119 | ! 2. Time splitting loop |
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| 120 | ! ---------------------- |
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| 121 | |
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| 122 | DO jl = 1, n_zdfexp |
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| 123 | |
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| 124 | ! first vertical derivative |
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| 125 | IF( lk_zdfddm ) THEN ! double diffusion: avs /= avt |
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| 126 | DO jk = 2, jpk |
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| 127 | DO ji = 2, jpim1 |
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| 128 | zave3r = 1.e0 / fse3w(ji,jj,jk) |
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| 129 | zwy(ji,jk) = avt(ji,jj,jk) * ( zwx(ji,jk-1) - zwx(ji,jk) ) * zave3r |
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| 130 | zww(ji,jk) = fsavs(ji,jj,jk) * ( zwz(ji,jk-1) - zwz(ji,jk) ) * zave3r |
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| 131 | END DO |
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| 132 | END DO |
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| 133 | ELSE ! default : avs = avt |
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| 134 | DO jk = 2, jpk |
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| 135 | DO ji = 2, jpim1 |
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| 136 | zave3r = avt(ji,jj,jk) / fse3w(ji,jj,jk) |
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| 137 | zwy(ji,jk) = zave3r *(zwx(ji,jk-1) - zwx(ji,jk) ) |
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| 138 | zww(ji,jk) = zave3r *(zwz(ji,jk-1) - zwz(ji,jk) ) |
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| 139 | END DO |
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| 140 | END DO |
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| 141 | ENDIF |
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| 142 | |
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| 143 | ! trend estimation at kt+l*2*rdt/n_zdfexp |
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| 144 | DO jk = 1, jpkm1 |
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| 145 | DO ji = 2, jpim1 |
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| 146 | ze3tr = zlavmr / fse3t(ji,jj,jk) |
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| 147 | ! 2nd vertical derivative |
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| 148 | zta = ( zwy(ji,jk) - zwy(ji,jk+1) ) * ze3tr |
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| 149 | zsa = ( zww(ji,jk) - zww(ji,jk+1) ) * ze3tr |
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| 150 | ! update the tracer trends |
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| 151 | ta(ji,jj,jk) = ta(ji,jj,jk) + zta |
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| 152 | sa(ji,jj,jk) = sa(ji,jj,jk) + zsa |
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| 153 | ! update tracer fields at kt+l*2*rdt/n_zdfexp |
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[457] | 154 | zwx(ji,jk) = zwx(ji,jk) + p2dt(jk) * zta * tmask(ji,jj,jk) |
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| 155 | zwz(ji,jk) = zwz(ji,jk) + p2dt(jk) * zsa * tmask(ji,jj,jk) |
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[3] | 156 | END DO |
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| 157 | END DO |
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| 158 | END DO |
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| 159 | ! ! =============== |
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| 160 | END DO ! End of slab |
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| 161 | ! ! =============== |
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[216] | 162 | |
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[3] | 163 | END SUBROUTINE tra_zdf_exp |
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| 164 | |
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| 165 | !!============================================================================== |
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| 166 | END MODULE trazdf_exp |
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