1 | MODULE dynzdf_exp |
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2 | !!============================================================================== |
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3 | !! *** MODULE dynzdf_exp *** |
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4 | !! Ocean dynamics: vertical component(s) of the momentum mixing trend |
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5 | !!============================================================================== |
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6 | |
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7 | !!---------------------------------------------------------------------- |
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8 | !! dyn_zdf_exp : update the momentum trend with the vertical diffu- |
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9 | !! sion using an explicit time-stepping scheme. |
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10 | !!---------------------------------------------------------------------- |
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11 | !! * Modules used |
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12 | USE oce ! ocean dynamics and tracers |
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13 | USE dom_oce ! ocean space and time domain |
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14 | USE phycst ! physical constants |
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15 | USE zdf_oce ! ocean vertical physics |
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16 | USE in_out_manager ! I/O manager |
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17 | USE taumod ! surface ocean stress |
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18 | USE trddyn_oce ! dynamics trends diagnostics variables |
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19 | |
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20 | IMPLICIT NONE |
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21 | PRIVATE |
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22 | |
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23 | !! * Routine accessibility |
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24 | PUBLIC dyn_zdf_exp ! called by step.F90 |
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25 | |
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26 | !! * Substitutions |
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27 | # include "domzgr_substitute.h90" |
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28 | # include "vectopt_loop_substitute.h90" |
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29 | !!---------------------------------------------------------------------- |
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30 | !! OPA 9.0 , LODYC-IPSL (2003) |
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31 | !!---------------------------------------------------------------------- |
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32 | |
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33 | CONTAINS |
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34 | |
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35 | SUBROUTINE dyn_zdf_exp( kt ) |
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36 | !!---------------------------------------------------------------------- |
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37 | !! *** ROUTINE dyn_zdf_exp *** |
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38 | !! |
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39 | !! ** Purpose : Compute the trend due to the vert. momentum diffusion |
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40 | !! |
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41 | !! ** Method : Explicit forward time stepping with a time splitting |
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42 | !! technique. The vertical diffusion of momentum is given by: |
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43 | !! diffu = dz( avmu dz(u) ) = 1/e3u dk+1( avmu/e3uw dk(ub) ) |
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44 | !! Surface boundary conditions: wind stress input |
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45 | !! Bottom boundary conditions : bottom stress (cf zdfbfr.F90) |
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46 | !! Add this trend to the general trend ua : |
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47 | !! ua = ua + dz( avmu dz(u) ) |
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48 | !! |
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49 | !! ** Action : - Update (ua,va) with the vertical diffusive trend |
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50 | !! - Save the trends in (utrd,vtrd) ('key_diatrends') |
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51 | !! |
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52 | !! History : |
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53 | !! ! 90-10 (B. Blanke) Original code |
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54 | !! ! 97-05 (G. Madec) vertical component of isopycnal |
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55 | !! 8.5 ! 02-08 (G. Madec) F90: Free form and module |
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56 | !!--------------------------------------------------------------------- |
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57 | !! * Arguments |
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58 | INTEGER, INTENT( in ) :: kt ! ocean time-step index |
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59 | |
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60 | !! * Local declarations |
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61 | INTEGER :: ji, jj, jk, jl ! dummy loop indices |
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62 | REAL(wp) :: & |
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63 | zrau0r, zlavmr, z2dt, zua, zva ! temporary scalars |
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64 | REAL(wp), DIMENSION(jpi,jpk) :: & |
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65 | zwx, zwy, zwz, zww ! temporary workspace arrays |
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66 | #if defined key_trddyn |
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67 | INTEGER :: & |
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68 | ikbu, ikbum1 , ikbv, ikbvm1 ! temporary integers |
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69 | #endif |
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70 | !!---------------------------------------------------------------------- |
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71 | |
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72 | IF( kt == nit000 ) THEN |
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73 | IF(lwp) WRITE(numout,*) |
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74 | IF(lwp) WRITE(numout,*) 'dyn_zdf_exp : vertical momentum diffusion explicit operator' |
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75 | IF(lwp) WRITE(numout,*) '~~~~~~~~~~~ ' |
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76 | ENDIF |
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77 | |
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78 | ! Local constant initialization |
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79 | ! ----------------------------- |
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80 | zrau0r = 1. / rau0 ! inverse of the reference density |
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81 | zlavmr = 1. / float( n_zdfexp ) ! inverse of the number of sub time step |
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82 | z2dt = 2. * rdt ! Leap-frog environnement |
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83 | IF( neuler == 0 .AND. kt == nit000 ) z2dt = rdt ! Euler time stepping when starting from rest |
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84 | |
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85 | ! ! =============== |
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86 | DO jj = 2, jpjm1 ! Vertical slab |
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87 | ! ! =============== |
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88 | |
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89 | ! Surface boundary condition |
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90 | DO ji = 2, jpim1 |
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91 | zwy(ji,1) = taux(ji,jj) * zrau0r |
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92 | zww(ji,1) = tauy(ji,jj) * zrau0r |
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93 | END DO |
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94 | |
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95 | ! Initialization of x, z and contingently trends array |
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96 | DO jk = 1, jpk |
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97 | DO ji = 2, jpim1 |
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98 | zwx(ji,jk) = ub(ji,jj,jk) |
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99 | zwz(ji,jk) = vb(ji,jj,jk) |
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100 | #if defined key_trddyn |
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101 | utrd(ji,jj,jk,7) = ua(ji,jj,jk) |
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102 | vtrd(ji,jj,jk,7) = va(ji,jj,jk) |
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103 | #endif |
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104 | END DO |
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105 | END DO |
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106 | |
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107 | ! Time splitting loop |
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108 | DO jl = 1, n_zdfexp |
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109 | |
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110 | ! First vertical derivative |
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111 | DO jk = 2, jpk |
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112 | DO ji = 2, jpim1 |
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113 | zwy(ji,jk) = avmu(ji,jj,jk) * ( zwx(ji,jk-1) - zwx(ji,jk) ) / fse3uw(ji,jj,jk) |
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114 | zww(ji,jk) = avmv(ji,jj,jk) * ( zwz(ji,jk-1) - zwz(ji,jk) ) / fse3vw(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 | ! Second vertical derivative and trend estimation at kt+l*rdt/n_zdfexp |
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119 | DO jk = 1, jpkm1 |
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120 | DO ji = 2, jpim1 |
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121 | zua = zlavmr*( zwy(ji,jk) - zwy(ji,jk+1) ) / fse3u(ji,jj,jk) |
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122 | zva = zlavmr*( zww(ji,jk) - zww(ji,jk+1) ) / fse3v(ji,jj,jk) |
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123 | ua(ji,jj,jk) = ua(ji,jj,jk) + zua |
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124 | va(ji,jj,jk) = va(ji,jj,jk) + zva |
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125 | |
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126 | zwx(ji,jk) = zwx(ji,jk) + z2dt*zua*umask(ji,jj,jk) |
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127 | zwz(ji,jk) = zwz(ji,jk) + z2dt*zva*vmask(ji,jj,jk) |
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128 | END DO |
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129 | END DO |
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130 | |
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131 | END DO |
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132 | |
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133 | #if defined key_trddyn |
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134 | ! diagnose the vertical diffusive momentum trends |
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135 | |
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136 | ! save the total vertical momentum diffusive trend |
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137 | DO jk = 1, jpkm1 |
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138 | DO ji = 2, jpim1 |
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139 | utrd(ji,jj,jk,7) = ua(ji,jj,jk) - utrd(ji,jj,jk,7) |
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140 | vtrd(ji,jj,jk,7) = va(ji,jj,jk) - vtrd(ji,jj,jk,7) |
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141 | END DO |
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142 | END DO |
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143 | |
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144 | ! subtract and save surface and momentum fluxes |
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145 | DO ji = 2, jpim1 |
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146 | ! save the surface momentum fluxes |
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147 | tautrd(ji,jj,1) = zwy(ji,1) / fse3u(ji,jj,1) |
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148 | tautrd(ji,jj,2) = zww(ji,1) / fse3v(ji,jj,1) |
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149 | ! save bottom friction momentum fluxes |
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150 | ikbu = MIN( mbathy(ji+1,jj), mbathy(ji,jj) ) |
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151 | ikbum1 = MAX( ikbu-1, 1 ) |
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152 | ikbv = MIN( mbathy(ji,jj+1), mbathy(ji,jj) ) |
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153 | ikbvm1 = MAX( ikbv-1, 1 ) |
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154 | tautrd(ji,jj,3) = avmu(ji,jj,ikbu) * zwx(ji,ikbum1) & |
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155 | / ( fse3u(ji,jj,ikbum1) * fse3uw(ji,jj,ikbu) ) |
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156 | tautrd(ji,jj,4) = avmv(ji,jj,ikbv) * zwz(ji,ikbvm1) & |
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157 | / ( fse3v(ji,jj,ikbvm1) * fse3vw(ji,jj,ikbv) ) |
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158 | ! subtract surface forcing and bottom friction trend from vertical |
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159 | ! diffusive momentum trend |
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160 | utrd(ji,jj,1 ,7) = utrd(ji,jj,1 ,7) - tautrd(ji,jj,1) |
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161 | utrd(ji,jj,ikbum1,7) = utrd(ji,jj,ikbum1,7) - tautrd(ji,jj,3) |
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162 | vtrd(ji,jj,1 ,7) = vtrd(ji,jj,1 ,7) - tautrd(ji,jj,2) |
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163 | vtrd(ji,jj,ikbvm1,7) = vtrd(ji,jj,ikbvm1,7) - tautrd(ji,jj,4) |
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164 | END DO |
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165 | #endif |
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166 | ! ! =============== |
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167 | END DO ! End of slab |
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168 | ! ! =============== |
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169 | |
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170 | END SUBROUTINE dyn_zdf_exp |
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171 | |
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172 | !!============================================================================== |
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173 | END MODULE dynzdf_exp |
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