1 | MODULE trasbc |
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2 | !!============================================================================== |
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3 | !! *** MODULE trasbc *** |
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4 | !! Ocean active tracers: surface boundary condition |
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5 | !!============================================================================== |
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6 | |
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7 | !!---------------------------------------------------------------------- |
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8 | !! tra_sbc : update the tracer trend at ocean surface |
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9 | !!---------------------------------------------------------------------- |
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10 | !! * Modules used |
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11 | USE oce ! ocean dynamics and active tracers |
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12 | USE dom_oce ! ocean space domain variables |
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13 | USE ocesbc ! surface thermohaline fluxes |
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14 | USE phycst ! physical constant |
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15 | USE traqsr ! ??? |
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16 | USE trdtra_oce ! ocean active tracer trends |
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17 | USE in_out_manager ! I/O manager |
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18 | |
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19 | IMPLICIT NONE |
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20 | PRIVATE |
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21 | |
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22 | !! * Routine accessibility |
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23 | PUBLIC tra_sbc ! routine called by step.F90 |
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24 | |
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25 | !! * Substitutions |
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26 | # include "domzgr_substitute.h90" |
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27 | # include "vectopt_loop_substitute.h90" |
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28 | !!---------------------------------------------------------------------- |
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29 | !! OPA 9.0 , LODYC-IPSL (2003) |
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30 | !!---------------------------------------------------------------------- |
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31 | |
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32 | CONTAINS |
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33 | |
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34 | SUBROUTINE tra_sbc ( kt ) |
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35 | !!---------------------------------------------------------------------- |
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36 | !! *** ROUTINE tra_sbc *** |
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37 | !! |
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38 | !! ** Purpose : Compute the tracer surface boundary condition trend of |
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39 | !! (flux through the interface, concentration/dilution effect) |
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40 | !! and add it to the general trend of tracer equations. |
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41 | !! |
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42 | !! ** Method : |
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43 | !! * flux through the air-sea interface: |
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44 | !! - temperature : heat flux q (w/m2). If penetrative solar |
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45 | !! radiation q is only the non solar part of the heat flux, the |
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46 | !! solar part is added in traqsr.F routine. |
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47 | !! ta = ta + q /(rau0 rcp e3t) for k=1 |
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48 | !! - salinity : no salt flux |
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49 | !! * concentration/dilution effect: |
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50 | !! The surface freshwater flux modify the ocean volume |
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51 | !! and thus the concentration of a tracer and the temperature. |
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52 | !! First order of the effect of surface freshwater exchange |
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53 | !! for salinity, it can be neglected on temperature (especially |
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54 | !! as the temparature of precipitations and runoffs is usually |
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55 | !! unknown. |
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56 | !! - temperature : we assume that the temperature of both |
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57 | !! precipitations and runoffs is equal to the SST, thus there |
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58 | !! is no additional flux since in this case, the concentration |
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59 | !! dilution effect is balanced by the net heat flux associated |
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60 | !! to the freshwater exchange: |
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61 | !! (Tp P - Te E) + STT (P-E) = 0 when Tp=Te=SST |
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62 | !! - salinity : evaporation, precipitation and runoff |
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63 | !! water has a zero salinity, thus |
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64 | !! sa = sa + emp * sn / e3t for k=1 |
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65 | !! where emp, the surface freshwater budget (evaporation minus |
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66 | !! precipitation minus runoff) given in kg/m2/s is divided |
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67 | !! by 1000 kg/m3 (density of plain water) to obtain m/s. |
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68 | !! |
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69 | !! ** Action : - Update the 1st level of (ta,sa) with the trend associated |
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70 | !! with the tracer surface boundary condition |
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71 | !! - save the trend it in ttrd ('key_trdtra') |
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72 | !! |
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73 | !! History : |
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74 | !! 8.2 ! 98-10 (G. Madec, G. Roullet, M. Imbard) Original code |
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75 | !! 8.2 ! 01-02 (D. Ludicone) sea ice and free surface |
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76 | !! 8.5 ! 02-06 (G. Madec) F90: Free form and module |
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77 | !!---------------------------------------------------------------------- |
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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 ! dummy loop indices |
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83 | REAL(wp) :: zta, zsa, zsrau, zse3t ! temporary scalars |
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84 | !!---------------------------------------------------------------------- |
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85 | |
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86 | IF( kt == nit000 ) THEN |
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87 | IF(lwp) WRITE(numout,*) |
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88 | IF(lwp) WRITE(numout,*) 'tra_sbc : TRAcer Surface Boundary Condition' |
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89 | IF(lwp) WRITE(numout,*) '~~~~~~~ ' |
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90 | ENDIF |
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91 | |
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92 | ! 0. initialization |
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93 | zsrau = 1. / rauw |
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94 | #if ! defined key_s_coord |
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95 | zse3t = 1. / fse3t(1,1,1) |
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96 | #endif |
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97 | |
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98 | IF( .NOT.ln_traqsr ) qsr(:,:) = 0.e0 ! no solar radiation penetration |
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99 | |
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100 | ! 1. Concentration dillution effect on (t,s) |
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101 | DO jj = 2, jpj |
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102 | DO ji = fs_2, fs_jpim1 ! vector opt. |
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103 | #if defined key_s_coord |
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104 | zse3t = 1. / fse3t(ji,jj,1) |
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105 | #endif |
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106 | ! temperature : heat flux |
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107 | zta = ro0cpr * ( qt(ji,jj) - qsr(ji,jj) ) * zse3t |
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108 | |
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109 | ! salinity : concent./dilut. effect |
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110 | zsa = emps(ji,jj) * zsrau * sn(ji,jj,1) * zse3t |
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111 | |
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112 | ! add the trend to the general tracer trend |
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113 | ta(ji,jj,1) = ta(ji,jj,1) + zta |
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114 | sa(ji,jj,1) = sa(ji,jj,1) + zsa |
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115 | #if defined key_trdtra || defined key_trdmld |
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116 | ! save the trend associated to (t,s) sea surface boundary condition |
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117 | flxtrd(ji,jj,1) = zta |
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118 | flxtrd(ji,jj,2) = zsa |
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119 | #endif |
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120 | END DO |
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121 | END DO |
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122 | |
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123 | IF(l_ctl) THEN ! print mean trends (used for debugging) |
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124 | zta = SUM( ta(2:jpim1,2:jpjm1,1:jpkm1) * tmask(2:jpim1,2:jpjm1,1:jpkm1) ) |
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125 | zsa = SUM( sa(2:jpim1,2:jpjm1,1:jpkm1) * tmask(2:jpim1,2:jpjm1,1:jpkm1) ) |
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126 | WRITE(numout,*) ' sbc - Ta: ', zta, ' Sa: ', zsa |
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127 | t_ctl = zta ; s_ctl = zsa |
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128 | ENDIF |
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129 | |
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130 | END SUBROUTINE tra_sbc |
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131 | |
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132 | !!====================================================================== |
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133 | END MODULE trasbc |
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