1 | MODULE trcoxy_medusa |
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2 | !!====================================================================== |
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3 | !! *** MODULE trcoxy_medusa *** |
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4 | !! TOP : MEDUSA |
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5 | !!====================================================================== |
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6 | !! History : |
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7 | !! - ! 2011-07 (A. Yool) added for ROAM project |
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8 | !!---------------------------------------------------------------------- |
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9 | #if defined key_medusa && defined key_roam |
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10 | !!---------------------------------------------------------------------- |
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11 | !! MEDUSA oxygen cycle |
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12 | !!---------------------------------------------------------------------- |
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13 | !! trc_oxy_medusa : |
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14 | !!---------------------------------------------------------------------- |
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15 | USE oce_trc |
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16 | USE trc |
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17 | USE sms_medusa |
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18 | USE lbclnk |
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19 | USE prtctl_trc ! Print control for debugging |
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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 | PUBLIC trc_oxy_medusa ! called in trc_bio_medusa |
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25 | |
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26 | !!* Substitution |
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27 | # include "domzgr_substitute.h90" |
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28 | !!---------------------------------------------------------------------- |
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29 | !! NEMO/TOP 2.0 , LOCEAN-IPSL (2007) |
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30 | !! $Id: trcbio.F90 1146 2008-06-25 11:42:56Z rblod $ |
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31 | !! Software governed by the CeCILL licence (modipsl/doc/NEMO_CeCILL.txt) |
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32 | !!---------------------------------------------------------------------- |
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33 | |
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34 | ! The following is a map of the subroutines contained within this module |
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35 | ! - trc_oxy_medusa |
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36 | ! - CALLS gas_transfer |
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37 | ! - CALLS oxy_schmidt |
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38 | ! - CALLS oxy_sato |
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39 | |
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40 | CONTAINS |
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41 | |
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42 | !======================================================================= |
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43 | ! |
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44 | SUBROUTINE trc_oxy_medusa( pt, ps, uwind, vwind, pp0, o2, dz, & !! inputs |
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45 | kw660, o2flux, o2sat ) !! outputs |
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46 | ! |
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47 | !======================================================================= |
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48 | !! |
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49 | !! Title : Calculates O2 change due to air-sea gas exchange |
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50 | !! Author : Andrew Yool |
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51 | !! Date : 15/10/04 (revised 08/07/11) |
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52 | !! |
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53 | !! This subroutine calculates oxygen air-sea gas exchange in the |
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54 | !! surface layer of the ocean. The formulation is taken from one |
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55 | !! written by Ray Najjar for the OCMIP-2 project. The routine |
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56 | !! calls two other subroutines, oxy_schmidt.f (calculates Schmidt |
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57 | !! number of oxygen) and oxy_sato.f (calculates oxygen saturation |
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58 | !! concentration at 1 atm). |
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59 | !! |
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60 | !! Function inputs are (in order) : |
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61 | !! pt temperature (degrees C) |
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62 | !! ps salinity (PSU) |
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63 | !! uwind u-wind velocity (m/s) |
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64 | !! vwind v-wind velocity (m/s) |
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65 | !! pp0 surface pressure (divided by 1 atm) |
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66 | !! o2 surface O2 concentration (mol/m3) |
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67 | !! dz surface layer thickness (m) |
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68 | !! (*) kw660 gas transfer velocity (m/s) |
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69 | !! (*) o2flux exchange rate of oxygen (mol/m3/s) |
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70 | !! (+) o2sat oxygen saturation concentration (mol/m3) |
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71 | !! |
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72 | !! Where (*) is the function output (note its units). |
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73 | !! |
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74 | !======================================================================= |
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75 | |
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76 | implicit none |
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77 | ! |
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78 | REAL(wp), INTENT( in ) :: pt |
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79 | REAL(wp), INTENT( in ) :: ps |
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80 | REAL(wp), INTENT( in ) :: uwind |
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81 | REAL(wp), INTENT( in ) :: vwind |
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82 | REAL(wp), INTENT( in ) :: pp0 |
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83 | REAL(wp), INTENT( in ) :: o2 |
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84 | REAL(wp), INTENT( in ) :: dz |
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85 | REAL(wp), INTENT( inout ) :: kw660, o2flux, o2sat |
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86 | ! |
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87 | REAL(wp) :: scl_wind, kwo2, o2schmidt, o2sato |
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88 | ! |
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89 | ! Calculate gas transfer |
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90 | ! |
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91 | call gas_transfer(uwind, vwind, scl_wind, kw660) |
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92 | ! |
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93 | ! Calculate oxygen Schmidt number |
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94 | ! |
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95 | call oxy_schmidt(pt, o2schmidt) |
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96 | ! |
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97 | ! Calculate the transfer velocity for O2 (m/s) |
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98 | ! |
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99 | kwo2 = kw660 * (660 / o2schmidt)**0.5 |
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100 | ! |
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101 | ! Calculate the saturation concentration for oxygen (mol/m3) |
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102 | ! |
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103 | call oxy_sato(pt, ps, o2sato) |
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104 | o2sat = o2sato * pp0 |
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105 | ! |
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106 | ! Calculate time rate of change of O2 due to gas exchange (mol/m3/s) |
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107 | ! |
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108 | o2flux = kwo2 * (o2sat - o2) / dz |
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109 | ! |
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110 | END SUBROUTINE trc_oxy_medusa |
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111 | |
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112 | !======================================================================= |
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113 | !======================================================================= |
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114 | !======================================================================= |
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115 | |
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116 | !======================================================================= |
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117 | ! |
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118 | SUBROUTINE oxy_schmidt( pt, & !! input |
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119 | o2_schmidt ) !! output |
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120 | ! |
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121 | !======================================================================= |
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122 | !! |
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123 | !! Title : Calculates Schmidt number for ocean uptake of O2 |
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124 | !! Author : Andrew Yool |
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125 | !! Date : 14/10/04 (revised 08/07/11) |
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126 | !! |
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127 | !! This subroutine calculates the Schmidt number for O2 using sea |
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128 | !! surface temperature. The code is based upon that developed as |
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129 | !! part of the OCMIP-2 project (1998-2000). The coefficients used |
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130 | !! are taken from Keeling et al. (1998, GBC, 12, 141-163). |
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131 | !! |
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132 | !! Function inputs are (in order) : |
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133 | !! t temperature (degrees C) |
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134 | !! (*) o2_schmidt oxygen Schmidt number |
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135 | !! |
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136 | !! Where (*) is the function output. |
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137 | !! |
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138 | !======================================================================= |
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139 | |
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140 | implicit none |
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141 | ! |
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142 | REAL(wp) :: pt, o2_schmidt |
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143 | REAL(wp) :: a0, a1, a2, a3 |
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144 | ! |
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145 | data a0 / 1638.0 / |
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146 | data a1 / -81.83 / |
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147 | data a2 / 1.483 / |
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148 | data a3 / -0.008004 / |
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149 | ! |
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150 | o2_schmidt = a0 + pt*(a1 + pt*(a2 + pt*a3)) |
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151 | ! |
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152 | END SUBROUTINE oxy_schmidt |
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153 | |
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154 | !======================================================================= |
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155 | !======================================================================= |
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156 | !======================================================================= |
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157 | |
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158 | !======================================================================= |
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159 | ! |
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160 | SUBROUTINE oxy_sato( pt, ps, & !! inputs |
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161 | o2_sato ) !! output |
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162 | ! |
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163 | !======================================================================= |
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164 | !! |
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165 | !! Title : Calculates O2 saturation at 1 atm pressure |
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166 | !! Author : Andrew Yool |
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167 | !! Date : 14/10/04 (revised 08/07/11) |
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168 | !! |
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169 | !! This subroutine calculates the oxygen saturation concentration |
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170 | !! at 1 atmosphere pressure in mol/m3 given ambient temperature |
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171 | !! and salinity. This formulation is (ostensibly) taken from |
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172 | !! Garcia & Gordon (1992, L&O, 1307-1312). The function works |
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173 | !! in the range -1.9 <= T <= 40, 0 <= S <= 42. |
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174 | !! |
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175 | !! Function inputs are (in order) : |
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176 | !! pt temperature (degrees C) |
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177 | !! ps salinity (PSU) |
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178 | !! (*) o2_sato oxygen saturation (mol/m3) |
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179 | !! |
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180 | !! Where (*) is the function output (note its units). |
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181 | !! |
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182 | !! Check value : T = 10, S = 35, oxy_sato = 0.282015 mol/m3 |
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183 | !! |
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184 | !======================================================================= |
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185 | |
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186 | implicit none |
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187 | ! |
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188 | REAL(wp) :: pt, ps, o2_sato |
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189 | ! |
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190 | REAL(wp) :: a0, a1, a2, a3, a4, a5 |
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191 | REAL(wp) :: b0, b1, b2, b3 |
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192 | REAL(wp) :: c0 |
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193 | ! |
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194 | REAL(wp) :: tt, tk, ts, ts2, ts3, ts4, ts5 |
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195 | REAL(wp) :: ans1, ans2 |
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196 | ! |
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197 | data a0 / 2.00907 / |
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198 | data a1 / 3.22014 / |
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199 | data a2 / 4.05010 / |
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200 | data a3 / 4.94457 / |
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201 | data a4 / -2.56847E-1 / |
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202 | data a5 / 3.88767 / |
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203 | ! |
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204 | data b0 / -6.24523E-3 / |
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205 | data b1 / -7.37614E-3 / |
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206 | data b2 / -1.03410E-2 / |
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207 | data b3 / -8.17083E-3 / |
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208 | ! |
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209 | data c0 / -4.88682E-7 / |
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210 | ! |
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211 | tt = 298.15 - pt |
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212 | tk = 273.15 + pt |
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213 | ts = log(tt / tk) |
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214 | ts2 = ts**2 |
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215 | ts3 = ts**3 |
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216 | ts4 = ts**4 |
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217 | ts5 = ts**5 |
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218 | ans1 = a0 + a1*ts + a2*ts2 + a3*ts3 + a4*ts4 + a5*ts5 & |
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219 | + ps*(b0 + b1*ts + b2*ts2 + b3*ts3) & |
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220 | + c0*(ps*ps) |
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221 | ans2 = exp(ans1) |
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222 | ! |
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223 | ! Convert from ml/l to mol/m3 |
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224 | ! |
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225 | o2_sato = (ans2 / 22391.6) * 1000.0 |
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226 | ! |
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227 | END SUBROUTINE oxy_sato |
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228 | |
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229 | !======================================================================= |
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230 | !======================================================================= |
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231 | !======================================================================= |
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232 | |
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233 | !======================================================================= |
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234 | ! |
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235 | SUBROUTINE gas_transfer( uwind, vwind, & !! input |
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236 | scl_wind, k ) !! output |
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237 | ! |
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238 | !======================================================================= |
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239 | !! |
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240 | !! Title : Calculates gas transfer velocity |
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241 | !! Author : Andrew Yool |
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242 | !! Date : 15/10/04 (revised 04/08/2011) |
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243 | !! |
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244 | !! This subroutine uses near-surface wind speed to calculate gas |
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245 | !! transfer velocity for use in CO2 and O2 exchange calculations. |
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246 | !! |
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247 | !! Note that the parameterisation of Wanninkhof quoted here is a |
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248 | !! truncation of the original equation. It excludes a chemical |
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249 | !! enhancement function (based on temperature), although such |
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250 | !! temperature dependence is reported negligible by Etcheto & |
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251 | !! Merlivat (1988). |
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252 | !! |
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253 | !! Note also that in calculating scalar wind, the variance of the |
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254 | !! wind over the period of a timestep is ignored. Some authors, |
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255 | !! for instance OCMIP-2, favour including some reference to the |
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256 | !! variability of wind. However, their wind fields are averaged |
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257 | !! over relatively long time periods, and so this issue may be |
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258 | !! safely (!) ignored here. |
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259 | !! |
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260 | !! Subroutine inputs are (in order) : |
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261 | !! uwind wind u velocity at 10 m (m/s) |
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262 | !! vwind wind v velocity at 10 m (m/s) |
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263 | !! (+) scl_wind scalar wind velocity at 10 m (m/s) |
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264 | !! (*) k gas transfer velocity (m/s) |
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265 | !! Where (*) is the function output and (+) is a diagnostic output. |
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266 | !! |
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267 | !======================================================================= |
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268 | |
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269 | implicit none |
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270 | ! |
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271 | ! Input variables |
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272 | REAL(wp) :: uwind, vwind |
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273 | ! |
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274 | ! Output variables |
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275 | REAL(wp) :: scl_wind, k, tmp_k |
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276 | ! |
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277 | ! Choice of parameterisation |
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278 | INTEGER :: eqn |
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279 | ! |
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280 | ! Coefficients for various parameterisations |
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281 | REAL(wp), DIMENSION(6) :: a |
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282 | REAL(wp), DIMENSION(6) :: b |
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283 | ! |
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284 | ! Values of coefficients |
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285 | data a(1) / 0.166 / ! Liss & Merlivat (1986) [approximated] |
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286 | data a(2) / 0.3 / ! Wanninkhof (1992) [sans enhancement] |
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287 | data a(3) / 0.23 / ! Nightingale et al. (2000) [good] |
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288 | data a(4) / 0.23 / ! Nightingale et al. (2000) [better] |
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289 | data a(5) / 0.222 / ! Nightingale et al. (2000) [best] |
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290 | data a(6) / 0.337 / ! OCMIP-2 [sans variability] |
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291 | ! |
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292 | data b(1) / 0.133 / |
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293 | data b(2) / 0.0 / |
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294 | data b(3) / 0.0 / |
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295 | data b(4) / 0.1 / |
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296 | data b(5) / 0.333 / |
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297 | data b(6) / 0.0 / |
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298 | ! |
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299 | ! Which parameterisation is to be used? |
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300 | eqn = 2 |
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301 | ! |
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302 | ! Calculate scalar wind (m/s) |
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303 | scl_wind = (uwind**2 + vwind**2)**0.5 |
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304 | ! |
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305 | ! Calculate gas transfer velocity (cm/h) |
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306 | tmp_k = (a(eqn) * scl_wind**2) + (b(eqn) * scl_wind) |
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307 | ! |
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308 | ! Convert tmp_k from cm/h to m/s |
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309 | k = tmp_k / (100. * 3600.) |
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310 | ! |
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311 | END SUBROUTINE gas_transfer |
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312 | |
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313 | !======================================================================= |
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314 | !======================================================================= |
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315 | !======================================================================= |
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316 | |
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317 | #else |
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318 | !!====================================================================== |
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319 | !! Dummy module : No MEDUSA bio-model |
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320 | !!====================================================================== |
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321 | |
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322 | CONTAINS |
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323 | |
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324 | SUBROUTINE trc_oxy_medusa( pt, ps, uwind, vwind, pp0, o2, dz, & !! inputs |
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325 | kw660, o2flux, o2sat ) !! outputs |
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326 | USE par_kind |
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327 | |
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328 | REAL(wp), INTENT( in ) :: pt |
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329 | REAL(wp), INTENT( in ) :: ps |
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330 | REAL(wp), INTENT( in ) :: pp0 |
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331 | REAL(wp), INTENT( in ) :: o2 |
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332 | REAL(wp), INTENT( in ) :: dz |
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333 | REAL(wp), INTENT( inout ) :: kw660, o2flux, o2sat |
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334 | |
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335 | WRITE(*,*) 'trc_oxy_medusa: You should not have seen this print! error?', kt |
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336 | |
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337 | END SUBROUTINE trc_oxy_medusa |
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338 | #endif |
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339 | |
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340 | !!====================================================================== |
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341 | END MODULE trcoxy_medusa |
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342 | |
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