1 | MODULE trabbl |
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2 | !!============================================================================== |
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3 | !! *** MODULE trabbl *** |
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4 | !! Ocean physics : advective and/or diffusive bottom boundary layer scheme |
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5 | !!============================================================================== |
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6 | #if defined key_trabbl_dif || defined key_trabbl_adv || defined key_esopa |
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7 | !!---------------------------------------------------------------------- |
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8 | !! 'key_trabbl_dif' or diffusive bottom boundary layer |
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9 | !!---------------------------------------------------------------------- |
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10 | !! tra_bbl_dif : update the active tracer trends due to the bottom |
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11 | !! boundary layer (diffusive only) |
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12 | !! tra_bbl_init : initialization, namlist read, parameters control |
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13 | !!---------------------------------------------------------------------- |
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14 | !! OPA 9.0 , LOCEAN-IPSL (2005) |
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15 | !! $Header$ |
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16 | !! This software is governed by the CeCILL licence see modipsl/doc/NEMO_CeCILL.txt |
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17 | !!---------------------------------------------------------------------- |
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18 | !! * Modules used |
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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_bbl_dif ! routine called by step.F90 |
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26 | |
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27 | !! * Shared module variables |
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28 | REAL(wp), PUBLIC :: & !!: * bbl namelist * |
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29 | atrbbl = 1.e+3 !: lateral coeff. for bottom boundary |
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30 | ! ! layer scheme (m2/s) |
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31 | REAL(wp) , PUBLIC , DIMENSION(jpi,jpj) :: & |
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32 | bblx, bbly ! Bottom boundary layer coefficients |
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33 | |
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34 | !! * Substitutions |
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35 | # include "domzgr_substitute.h90" |
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36 | # include "vectopt_loop_substitute.h90" |
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37 | |
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38 | CONTAINS |
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39 | |
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40 | SUBROUTINE tra_bbl_dif( kt ) |
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41 | !!---------------------------------------------------------------------- |
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42 | !! *** ROUTINE tra_bbl_dif *** |
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43 | !! |
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44 | !! ** Purpose : Compute the before tracer (t & s) trend associated |
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45 | !! with the bottom boundary layer and add it to the general trend |
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46 | !! of tracer equations. The bottom boundary layer is supposed to be |
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47 | !! a purely diffusive bottom boundary layer. |
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48 | !! |
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49 | !! ** Method : When the product grad( rho) * grad(h) < 0 (where grad |
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50 | !! is an along bottom slope gradient) an additional lateral diffu- |
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51 | !! sive trend along the bottom slope is added to the general tracer |
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52 | !! trend, otherwise nothing is done. |
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53 | !! Second order operator (laplacian type) with variable coefficient |
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54 | !! computed as follow for temperature (idem on s): |
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55 | !! difft = 1/(e1t*e2t*e3t) { di-1[ ahbt e2u*e3u/e1u di[ztb] ] |
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56 | !! + dj-1[ ahbt e1v*e3v/e2v dj[ztb] ] } |
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57 | !! where ztb is a 2D array: the bottom ocean temperature and ahtb |
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58 | !! is a time and space varying diffusive coefficient defined by: |
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59 | !! ahbt = zahbp if grad(rho).grad(h) < 0 |
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60 | !! = 0. otherwise. |
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61 | !! Note that grad(.) is the along bottom slope gradient. grad(rho) |
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62 | !! is evaluated using the local density (i.e. referenced at the |
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63 | !! local depth). Typical value of ahbt is 2000 m2/s (equivalent to |
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64 | !! a downslope velocity of 20 cm/s if the condition for slope |
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65 | !! convection is satified) |
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66 | !! Add this before trend to the general trend (ta,sa) of the |
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67 | !! botton ocean tracer point: |
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68 | !! ta = ta + difft |
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69 | !! |
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70 | !! ** Action : - update (ta,sa) at the bottom level with the bottom |
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71 | !! boundary layer trend |
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72 | !! - save the trends in bbltrd ('key_diatrends') |
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73 | !! |
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74 | !! References : |
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75 | !! Beckmann, A., and R. Doscher, 1997, J. Phys.Oceanogr., 581-591. |
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76 | !! |
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77 | !! History : |
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78 | !! 8.0 ! 96-06 (L. Mortier) Original code |
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79 | !! 8.0 ! 97-11 (G. Madec) Optimization |
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80 | !! 8.5 ! 02-08 (G. Madec) free form + modules |
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81 | !!---------------------------------------------------------------------- |
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82 | !! * Arguments |
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83 | INTEGER, INTENT( in ) :: kt ! ocean time-step |
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84 | |
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85 | !!---------------------------------------------------------------------- |
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86 | |
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87 | IF( kt == nit000 ) CALL tra_bbl_init |
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88 | |
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89 | END SUBROUTINE tra_bbl_dif |
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90 | |
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91 | SUBROUTINE tra_bbl_init |
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92 | !!---------------------------------------------------------------------- |
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93 | !! *** ROUTINE tra_bbl_init *** |
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94 | !! |
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95 | !! ** Purpose : Initialization for the bottom boundary layer scheme. |
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96 | !! |
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97 | !! ** Method : Read the nam_bbl namelist and check the parameters |
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98 | !! called by tra_bbl at the first timestep (nit000) |
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99 | !! |
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100 | !! History : |
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101 | !! 8.5 ! 02-08 (G. Madec) Original code |
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102 | !!---------------------------------------------------------------------- |
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103 | !! * Local declarations |
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104 | NAMELIST/nam_bbl/ atrbbl |
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105 | !!---------------------------------------------------------------------- |
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106 | |
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107 | ! Read Namelist nam_bbl : bottom boundary layer scheme |
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108 | ! -------------------- |
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109 | REWIND ( numnam ) |
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110 | READ ( numnam, nam_bbl ) |
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111 | |
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112 | ! Parameter control and print |
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113 | ! --------------------------- |
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114 | IF(lwp) THEN |
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115 | WRITE(numout,*) |
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116 | WRITE(numout,*) |
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117 | WRITE(numout,*) 'tra_bbl_init : * Diffusive Bottom Boundary Layer' |
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118 | WRITE(numout,*) '~~~~~~~~~~~~' |
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119 | WRITE(numout,*) ' Namelist nam_bbl : set bbl parameters' |
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120 | WRITE(numout,*) |
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121 | WRITE(numout,*) ' bottom boundary layer coef. atrbbl = ', atrbbl |
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122 | WRITE(numout,*) |
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123 | ENDIF |
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124 | |
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125 | END SUBROUTINE tra_bbl_init |
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126 | |
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127 | #else |
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128 | !!---------------------------------------------------------------------- |
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129 | !! Dummy module : No bottom boundary layer scheme |
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130 | !!---------------------------------------------------------------------- |
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131 | CONTAINS |
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132 | SUBROUTINE tra_bbl_dif (kt ) ! Empty routine |
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133 | INTEGER, INTENT(in) :: kt |
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134 | WRITE(*,*) 'tra_bbl_dif: You should not have seen this print! error?', kt |
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135 | END SUBROUTINE tra_bbl_dif |
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136 | #endif |
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137 | |
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138 | !!====================================================================== |
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139 | END MODULE trabbl |
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