[5841] | 1 | MODULE mocsy_gasflux |
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| 2 | |
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| 3 | CONTAINS |
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| 4 | |
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| 5 | ! -------------------------------------------------------------------- |
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| 6 | ! Schmidt CO2 number |
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| 7 | ! -------------------------------------------------------------------- |
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| 8 | ! |
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| 9 | ! Title : Calculates Schmidt number for ocean uptake of CO2 |
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| 10 | ! Author : Andrew Yool |
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| 11 | ! Date : 14/10/04 |
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| 12 | ! |
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| 13 | ! This function calculates the Schmidt number for CO2 using sea surface |
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| 14 | ! temperature. The code is based upon that developed as part of the |
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| 15 | ! OCMIP-2 project (1998-2000). The coefficients used are taken from |
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| 16 | ! Wanninkhof (1992, JGR, 97, 7373-7382). |
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| 17 | ! |
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| 18 | ! AXY (12/06/2015) |
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| 19 | ! UPDATED: coefficients used below are now those from Wanninkhof (2014) |
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| 20 | ! update to original 1992 paper. Full reference is: |
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| 21 | ! |
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| 22 | ! Winninkhof, R. (2014). Relationship between wind speed and gas |
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| 23 | ! exchange over the ocean revisited. LIMNOLOGY AND OCEANOGRAPHY-METHODS |
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| 24 | ! 12, 351-362, doi:10.4319/lom.2014.12.351 |
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| 25 | ! |
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| 26 | ! Check answer for the function at 20 degrees C is 668. |
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| 27 | ! |
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| 28 | ! Function inputs are (in order) : |
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| 29 | ! t temperature (degrees C) |
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| 30 | ! (*) co2_schmidt carbon dioxide Schmidt number |
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| 31 | ! |
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| 32 | ! Where (*) is the function output. |
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| 33 | ! |
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| 34 | subroutine schmidt_co2(pt, N, co2_schmidt) |
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| 35 | |
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| 36 | USE mocsy_singledouble |
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| 37 | |
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| 38 | implicit none |
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| 39 | ! |
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| 40 | INTEGER, INTENT(in) :: N |
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| 41 | real(kind=wp), INTENT(in), DIMENSION(N) :: pt |
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| 42 | real(kind=wp), INTENT(out), DIMENSION(N) :: co2_schmidt |
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| 43 | ! |
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| 44 | real(kind=wp) :: a0, a1, a2, a3, a4 |
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| 45 | ! |
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| 46 | ! data a0 / 2073.1 / |
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| 47 | ! data a1 / -125.62 / |
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| 48 | ! data a2 / 3.6276 / |
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| 49 | ! data a3 / -0.043219 / |
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| 50 | ! |
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| 51 | data a0 / 2116.8 / |
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| 52 | data a1 / -136.25 / |
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| 53 | data a2 / 4.7353 / |
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| 54 | data a3 / -0.092307 / |
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| 55 | data a4 / 0.0007555 / |
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| 56 | ! |
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| 57 | ! Wanninkhof (1992) |
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| 58 | ! co2_schmidt = a0 + pt*(a1 + pt*(a2 + pt*a3)) |
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| 59 | ! |
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| 60 | ! Wanninkhof (2014) adds in an extra term |
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| 61 | co2_schmidt = a0 + pt*(a1 + pt*(a2 + pt*(a3 + pt*a4))) |
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| 62 | ! |
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| 63 | return |
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| 64 | |
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| 65 | end subroutine schmidt_co2 |
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| 66 | |
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| 67 | ! -------------------------------------------------------------------- |
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| 68 | ! Surface K0 |
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| 69 | ! -------------------------------------------------------------------- |
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| 70 | ! |
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| 71 | ! Title : Calculates surface K0 from surface T & S |
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| 72 | ! Author : Andrew Yool |
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| 73 | ! Date : 18/06/15 |
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| 74 | ! |
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| 75 | ! This function is derived from code included in the MOCSY package |
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| 76 | ! produced by Jim Orr. |
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| 77 | ! |
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| 78 | subroutine surface_K0(ptmp, saln, N, K0) |
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| 79 | |
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| 80 | USE mocsy_singledouble |
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| 81 | |
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| 82 | implicit none |
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| 83 | ! |
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| 84 | INTEGER, INTENT(in) :: N |
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| 85 | real(kind=wp), INTENT(in), DIMENSION(N) :: ptmp, saln |
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| 86 | real(kind=wp), INTENT(out), DIMENSION(N) :: K0 |
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| 87 | ! |
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| 88 | real(kind=wp), DIMENSION(N) :: tk, invtk, tmp |
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| 89 | real(kind=wp) :: a0, a1, a2, a3, a4 |
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| 90 | ! |
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| 91 | tk = ptmp + 273.15d0 |
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| 92 | invtk = 1.0d0 / tk |
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| 93 | tmp = (9345.17d0*invtk) - 60.2409d0 + (23.3585d0 * LOG(tk/100.0d0)) |
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| 94 | K0 = EXP( tmp + saln*(0.023517d0 - (0.00023656d0*tk) + (0.0047036e-4_wp*tk*tk)) ) |
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| 95 | ! |
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| 96 | return |
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| 97 | |
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| 98 | end subroutine surface_K0 |
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| 99 | |
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| 100 | ! -------------------------------------------------------------------- |
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| 101 | ! Calculate xCO2 |
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| 102 | ! -------------------------------------------------------------------- |
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| 103 | ! |
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| 104 | !> Compute xCO2 from arrays of pCO2atm, in situ T, S, & atm pressure |
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| 105 | SUBROUTINE pCO2atm2xCO2(pCO2atm, temp, salt, Patm, N, xCO2) |
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| 106 | ! Purpose: |
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| 107 | ! Compute xCO2 from arrays of pCO2atm, in situ T, S, & atm pressure |
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| 108 | |
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| 109 | USE mocsy_singledouble |
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| 110 | |
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| 111 | IMPLICIT NONE |
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| 112 | |
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| 113 | !> number of records |
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| 114 | INTEGER, intent(in) :: N |
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| 115 | |
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| 116 | ! INPUT variables |
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| 117 | !> atmospheric partial pressure of CO2 [uatm] |
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| 118 | ! AXY (22/06/15): amended this next line to "in" as that's what it should be! |
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| 119 | REAL(kind=wp), INTENT(in), DIMENSION(N) :: pCO2atm |
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| 120 | !> in situ temperature [C] |
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| 121 | REAL(kind=wp), INTENT(in), DIMENSION(N) :: temp |
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| 122 | !> salinity [psu] |
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| 123 | REAL(kind=wp), INTENT(in), DIMENSION(N) :: salt |
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| 124 | !> atmospheric pressure [atm] |
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| 125 | REAL(kind=wp), INTENT(in), DIMENSION(N) :: Patm |
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| 126 | !f2py optional , depend(temp) :: n=len(temp) |
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| 127 | |
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| 128 | ! OUTPUT variables: |
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| 129 | !> mole fraction of CO2 [ppm] |
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| 130 | REAL(kind=wp), INTENT(out), DIMENSION(N) :: xCO2 |
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| 131 | |
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| 132 | ! LOCAL variables: |
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| 133 | REAL(kind=wp) :: dpCO2atm, dPatm |
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| 134 | REAL(kind=wp), DIMENSION(N) :: pH20 |
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| 135 | REAL(kind=wp) :: dxCO2 |
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| 136 | |
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| 137 | INTEGER :: i |
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| 138 | |
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| 139 | call vapress(temp, salt, N, pH20) |
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| 140 | |
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| 141 | DO i = 1,N |
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| 142 | dpCO2atm = DBLE(pCO2atm(i)) |
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| 143 | dPatm = DBLE(Patm(i)) |
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| 144 | dxCO2 = dpCO2atm / (dPatm - pH20(i)) |
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| 145 | xCO2(i) = REAL(dxCO2) |
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| 146 | END DO |
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| 147 | |
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| 148 | RETURN |
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| 149 | END SUBROUTINE pCO2atm2xCO2 |
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| 150 | |
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| 151 | ! -------------------------------------------------------------------- |
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| 152 | ! Calculate pCO2atm |
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| 153 | ! -------------------------------------------------------------------- |
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| 154 | ! |
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| 155 | !> Compute pCO2atm from arrays of xCO2, in situ T, S, & atm pressure |
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| 156 | SUBROUTINE x2pCO2atm(xCO2, temp, salt, Patm, N, pCO2atm) |
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| 157 | ! Purpose: |
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| 158 | ! Compute pCO2atm from arrays of xCO2, in situ T, S, & atm pressure |
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| 159 | |
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| 160 | USE mocsy_singledouble |
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| 161 | |
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| 162 | IMPLICIT NONE |
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| 163 | |
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| 164 | !> number of records |
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| 165 | INTEGER, intent(in) :: N |
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| 166 | |
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| 167 | ! INPUT variables |
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| 168 | !> mole fraction of CO2 [ppm] |
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| 169 | REAL(kind=wp), INTENT(in), DIMENSION(N) :: xCO2 |
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| 170 | !> in situ temperature [C] |
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| 171 | REAL(kind=wp), INTENT(in), DIMENSION(N) :: temp |
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| 172 | !> salinity [psu] |
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| 173 | REAL(kind=wp), INTENT(in), DIMENSION(N) :: salt |
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| 174 | !> atmospheric pressure [atm] |
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| 175 | REAL(kind=wp), INTENT(in), DIMENSION(N) :: Patm |
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| 176 | !f2py optional , depend(temp) :: n=len(temp) |
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| 177 | |
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| 178 | ! OUTPUT variables: |
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| 179 | !> oceanic partial pressure of CO2 [uatm] |
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| 180 | REAL(kind=wp), INTENT(out), DIMENSION(N) :: pCO2atm |
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| 181 | |
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| 182 | ! LOCAL variables: |
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| 183 | REAL(kind=wp) :: dxCO2, dPatm |
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| 184 | REAL(kind=wp), DIMENSION(N) :: pH20 |
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| 185 | REAL(kind=wp) :: dpCO2atm |
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| 186 | |
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| 187 | INTEGER :: i |
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| 188 | |
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| 189 | ! Compute vapor pressure of seawater [in atm] |
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| 190 | call vapress(temp, salt, N, pH20) |
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| 191 | |
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| 192 | DO i = 1,N |
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| 193 | dxCO2 = DBLE(xCO2(i)) |
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| 194 | dPatm = DBLE(Patm(i)) |
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| 195 | dpCO2atm = (dPatm - pH20(i)) * dxCO2 |
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| 196 | pCO2atm(i) = REAL(dpCO2atm) |
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| 197 | END DO |
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| 198 | |
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| 199 | RETURN |
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| 200 | END SUBROUTINE x2pCO2atm |
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| 201 | |
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| 202 | ! -------------------------------------------------------------------- |
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| 203 | ! Calculate seawater vapor pressure |
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| 204 | ! -------------------------------------------------------------------- |
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| 205 | ! |
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| 206 | !> Compute vapor pressure of seawater (atm) following preocedure from Weiss & Price (1980) |
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| 207 | SUBROUTINE vapress(temp, salt, N, vpsw) |
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| 208 | ! Purpose: |
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| 209 | ! Compute vapor pressure of seawater (atm) following preocedure from Weiss & Price (1980) |
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| 210 | |
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| 211 | USE mocsy_singledouble |
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| 212 | IMPLICIT NONE |
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| 213 | |
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| 214 | !> number of records |
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| 215 | INTEGER, intent(in) :: N |
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| 216 | |
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| 217 | ! INPUT variables |
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| 218 | !> in situ temperature [C] |
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| 219 | REAL(kind=wp), INTENT(in), DIMENSION(N) :: temp |
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| 220 | !> salinity [psu] |
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| 221 | REAL(kind=wp), INTENT(in), DIMENSION(N) :: salt |
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| 222 | !f2py optional , depend(temp) :: n=len(temp) |
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| 223 | |
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| 224 | ! OUTPUT variables: |
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| 225 | !> vapor pressure of seawater [atm] |
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| 226 | REAL(kind=wp), INTENT(out), DIMENSION(N) :: vpsw |
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| 227 | |
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| 228 | ! LOCAL variables: |
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| 229 | REAL(kind=wp) :: tk, dsalt |
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| 230 | |
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| 231 | INTEGER :: i |
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| 232 | |
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| 233 | DO i = 1,N |
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| 234 | dsalt = DBLE(salt(i)) |
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| 235 | tk = 273.15d0 + DBLE(temp(i)) !Absolute temperature (Kelvin) |
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| 236 | vpsw(i) = exp(24.4543d0 - 67.4509d0*(100.0d0/tk) - 4.8489d0*log(tk/100) - 0.000544d0*dsalt) |
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| 237 | END DO |
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| 238 | |
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| 239 | RETURN |
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| 240 | END SUBROUTINE vapress |
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| 241 | |
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| 242 | END MODULE mocsy_gasflux |
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