[325] | 1 | MODULE zdfddm |
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| 2 | !!====================================================================== |
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| 3 | !! *** MODULE zdfddm *** |
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| 4 | !! Ocean physics : double diffusion mixing parameterization |
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| 5 | !!====================================================================== |
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| 6 | #if defined key_zdfddm || defined key_esopa |
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| 7 | !!---------------------------------------------------------------------- |
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| 8 | !! 'key_zdfddm' : double diffusion |
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| 9 | !!---------------------------------------------------------------------- |
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| 10 | !! zdf_ddm : compute the Ks for salinity |
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| 11 | !! zdf_ddm_init : read namelist and control the parameters |
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| 12 | !!---------------------------------------------------------------------- |
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[343] | 13 | !! OPA 9.0 , LOCEAN-IPSL (2005) |
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[1152] | 14 | !! $Id$ |
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[343] | 15 | !! This software is governed by the CeCILL licence see modipsl/doc/NEMO_CeCILL.txt |
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| 16 | !!---------------------------------------------------------------------- |
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[325] | 17 | !! * Modules used |
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| 18 | USE oce ! ocean dynamics and tracers variables |
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| 19 | USE dom_oce ! ocean space and time domain variables |
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| 20 | USE zdf_oce ! ocean vertical physics variables |
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| 21 | USE in_out_manager ! I/O manager |
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| 22 | USE lbclnk ! ocean lateral boundary conditions (or mpp link) |
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| 23 | |
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| 24 | IMPLICIT NONE |
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| 25 | PRIVATE |
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| 26 | |
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| 27 | !! * Routine accessibility |
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| 28 | PUBLIC zdf_ddm ! called by step.F90 |
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| 29 | |
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| 30 | !! * Shared module variables |
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| 31 | LOGICAL, PUBLIC, PARAMETER :: lk_zdfddm = .TRUE. !: double diffusive mixing flag |
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| 32 | REAL(wp), PUBLIC, DIMENSION(jpi,jpj,jpk) :: & !: |
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| 33 | avs , & !: salinity vertical diffusivity coeff. at w-point |
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| 34 | rrau !: heat/salt buoyancy flux ratio |
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| 35 | |
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| 36 | !! * Module variables |
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| 37 | REAL(wp) :: & !!! * double diffusive mixing namelist * |
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| 38 | avts = 1.e-4_wp ! maximum value of avs for salt fingering |
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| 39 | |
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| 40 | !! * Substitutions |
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| 41 | # include "vectopt_loop_substitute.h90" |
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| 42 | |
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| 43 | CONTAINS |
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| 44 | |
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| 45 | SUBROUTINE zdf_ddm( kt ) |
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| 46 | !!---------------------------------------------------------------------- |
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| 47 | !! *** ROUTINE zdf_ddm *** |
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| 48 | !! |
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| 49 | !! ** Purpose : Add to the vertical eddy diffusivity coefficient the |
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| 50 | !! effect of salt fingering and diffusive convection. |
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| 51 | !! |
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| 52 | !! ** Method : Diapycnal mixing is increased in case of double |
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| 53 | !! diffusive mixing (i.e. salt fingering and diffusive layering) |
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| 54 | !! following Merryfield et al. (1999). The rate of double diffusive |
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| 55 | !! mixing depend on the buoyancy ratio: Rrau=alpha/beta dk[T]/dk[S] |
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| 56 | !! which is computed in rn2.F |
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| 57 | !! * salt fingering (Schmitt 1981): |
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| 58 | !! for Rrau > 1 and rn2 > 0 : zavfs = avts / ( 1 + (Rrau/hsbfr)^6 ) |
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| 59 | !! for Rrau > 1 and rn2 > 0 : zavfs = O |
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| 60 | !! otherwise : zavft = 0.7 zavs / Rrau |
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| 61 | !! * diffusive layering (Federov 1988): |
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| 62 | !! for 0< Rrau < 1 and rn2 > 0 : zavdt = 1.3635e-6 |
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| 63 | !! * exp( 4.6 exp(-0.54 (1/Rrau-1) ) ) |
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| 64 | !! otherwise : zavdt = 0 |
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| 65 | !! for .5 < Rrau < 1 and rn2 > 0 : zavds = zavdt (1.885 Rrau -0.85) |
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| 66 | !! for 0 < Rrau <.5 and rn2 > 0 : zavds = zavdt 0.15 Rrau |
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| 67 | !! otherwise : zavds = 0 |
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| 68 | !! * update the eddy diffusivity: |
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| 69 | !! avt = avt + zavft + zavdt |
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| 70 | !! avs = avs + zavfs + zavds |
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| 71 | !! avmu, avmv are required to remain at least above avt and avs. |
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| 72 | !! |
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| 73 | !! ** Action : avt, avs : update vertical eddy diffusivity coef. |
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| 74 | !! for temperature and salinity |
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| 75 | !! |
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| 76 | !! References : |
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| 77 | !! Merryfield et al., JPO, 29, 1124-1142, 1999. |
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| 78 | !! History : |
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| 79 | !! ! 00-08 (G. Madec) double diffusive mixing |
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| 80 | !! 8.5 ! 02-06 (G. Madec) F90: Free form and module |
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| 81 | !!---------------------------------------------------------------------- |
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| 82 | !! * Arguments |
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| 83 | INTEGER, INTENT( in ) :: kt ! ocean time-step indexocean time step |
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| 84 | |
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| 85 | !!---------------------------------------------------------------------- |
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| 86 | |
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| 87 | |
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| 88 | IF ( kt == nit000 ) CALL zdf_ddm_init ! Initialization (first time-step only) |
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| 89 | |
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| 90 | |
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| 91 | END SUBROUTINE zdf_ddm |
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| 92 | |
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| 93 | |
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| 94 | SUBROUTINE zdf_ddm_init |
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| 95 | !!---------------------------------------------------------------------- |
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| 96 | !! *** ROUTINE zdf_ddm_init *** |
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| 97 | !! |
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| 98 | !! ** Purpose : Initialization of double diffusion mixing scheme |
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| 99 | !! |
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[498] | 100 | !! ** Method : Read the nam_ddm namelist and check the parameter values |
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[325] | 101 | !! called by zdf_ddm at the first timestep (nit000) |
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| 102 | !! |
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| 103 | !! History : |
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| 104 | !! 8.5 ! 02-08 (G. Madec) Original code |
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| 105 | !!---------------------------------------------------------------------- |
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[498] | 106 | NAMELIST/nam_ddm/ avts |
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[325] | 107 | !!---------------------------------------------------------------------- |
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| 108 | |
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[498] | 109 | ! Read Namelist nam_ddm : double diffusion mixing scheme |
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[325] | 110 | ! -------------------- |
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| 111 | REWIND ( numnam ) |
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[498] | 112 | READ ( numnam, nam_ddm ) |
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[325] | 113 | |
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| 114 | |
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| 115 | ! Parameter control and print |
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| 116 | ! --------------------------- |
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| 117 | IF(lwp) THEN |
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| 118 | WRITE(numout,*) |
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| 119 | WRITE(numout,*) 'zdf_ddm : double diffusive mixing' |
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| 120 | WRITE(numout,*) '~~~~~~~' |
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[498] | 121 | WRITE(numout,*) ' Namelist nam_ddm : set dd mixing parameter' |
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[325] | 122 | WRITE(numout,*) ' maximum avs for dd mixing avts = ', avts |
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| 123 | WRITE(numout,*) |
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| 124 | ENDIF |
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| 125 | |
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| 126 | END SUBROUTINE zdf_ddm_init |
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| 127 | |
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| 128 | #else |
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| 129 | !!---------------------------------------------------------------------- |
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| 130 | !! Default option : Dummy module No double diffusion |
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| 131 | !!---------------------------------------------------------------------- |
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| 132 | LOGICAL, PUBLIC, PARAMETER :: lk_zdfddm = .FALSE. !: double diffusion flag |
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| 133 | CONTAINS |
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| 134 | SUBROUTINE zdf_ddm( kt ) ! Dummy routine |
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| 135 | WRITE(*,*) 'zdf_ddm: You should not have seen this print! error?', kt |
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| 136 | END SUBROUTINE zdf_ddm |
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| 137 | #endif |
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| 138 | |
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| 139 | !!====================================================================== |
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| 140 | END MODULE zdfddm |
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