[3] | 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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[1601] | 6 | !! History : OPA ! 2000-08 (G. Madec) double diffusive mixing |
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| 7 | !! NEMO 1.0 ! 2002-06 (G. Madec) F90: Free form and module |
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[4990] | 8 | !! 3.3 ! 2010-10 (C. Ethe, G. Madec) reorganisation of initialisation phase |
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| 9 | !! 3.6 ! 2013-04 (G. Madec, F. Roquet) zrau compute locally using interpolation of alpha & beta |
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[9019] | 10 | !! 4.0 ! 2017-04 (G. Madec) remove CPP ddm key & avm at t-point only |
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[1601] | 11 | !!---------------------------------------------------------------------- |
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[9019] | 12 | |
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[3] | 13 | !!---------------------------------------------------------------------- |
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[9019] | 14 | !! zdf_ddm : compute the Kz for salinity |
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[3] | 15 | !!---------------------------------------------------------------------- |
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[9019] | 16 | USE oce ! ocean dynamics and tracers variables |
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| 17 | USE dom_oce ! ocean space and time domain variables |
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| 18 | USE zdf_oce ! ocean vertical physics variables |
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[4990] | 19 | USE eosbn2 ! equation of state |
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| 20 | ! |
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[9019] | 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 | USE prtctl ! Print control |
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| 24 | USE lib_mpp ! MPP library |
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| 25 | USE timing ! Timing |
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[3] | 26 | |
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| 27 | IMPLICIT NONE |
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| 28 | PRIVATE |
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| 29 | |
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[2528] | 30 | PUBLIC zdf_ddm ! called by step.F90 |
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[3] | 31 | |
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| 32 | !! * Substitutions |
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| 33 | # include "vectopt_loop_substitute.h90" |
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| 34 | !!---------------------------------------------------------------------- |
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[4990] | 35 | !! NEMO/OPA 3.7 , NEMO Consortium (2014) |
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[2528] | 36 | !! $Id$ |
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[2715] | 37 | !! Software governed by the CeCILL licence (NEMOGCM/NEMO_CeCILL.txt) |
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[3] | 38 | !!---------------------------------------------------------------------- |
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| 39 | CONTAINS |
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| 40 | |
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[9019] | 41 | SUBROUTINE zdf_ddm( kt, p_avm, p_avt, p_avs ) |
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[2715] | 42 | !!---------------------------------------------------------------------- |
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[3] | 43 | !! *** ROUTINE zdf_ddm *** |
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| 44 | !! |
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| 45 | !! ** Purpose : Add to the vertical eddy diffusivity coefficient the |
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[1601] | 46 | !! effect of salt fingering and diffusive convection. |
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[3] | 47 | !! |
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| 48 | !! ** Method : Diapycnal mixing is increased in case of double |
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| 49 | !! diffusive mixing (i.e. salt fingering and diffusive layering) |
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| 50 | !! following Merryfield et al. (1999). The rate of double diffusive |
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[4990] | 51 | !! mixing depend on the buoyancy ratio (R=alpha/beta dk[T]/dk[S]): |
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[3] | 52 | !! * salt fingering (Schmitt 1981): |
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[4990] | 53 | !! for R > 1 and rn2 > 0 : zavfs = rn_avts / ( 1 + (R/rn_hsbfr)^6 ) |
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| 54 | !! for R > 1 and rn2 > 0 : zavfs = O |
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| 55 | !! otherwise : zavft = 0.7 zavs / R |
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[3] | 56 | !! * diffusive layering (Federov 1988): |
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[4990] | 57 | !! for 0< R < 1 and N^2 > 0 : zavdt = 1.3635e-6 * exp( 4.6 exp(-0.54 (1/R-1) ) ) |
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[3] | 58 | !! otherwise : zavdt = 0 |
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[4990] | 59 | !! for .5 < R < 1 and N^2 > 0 : zavds = zavdt (1.885 R -0.85) |
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| 60 | !! for 0 < R <.5 and N^2 > 0 : zavds = zavdt 0.15 R |
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[3] | 61 | !! otherwise : zavds = 0 |
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| 62 | !! * update the eddy diffusivity: |
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| 63 | !! avt = avt + zavft + zavdt |
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| 64 | !! avs = avs + zavfs + zavds |
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[9019] | 65 | !! avm is required to remain at least above avt and avs. |
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[3] | 66 | !! |
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[1601] | 67 | !! ** Action : avt, avs : updated vertical eddy diffusivity coef. for T & S |
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[3] | 68 | !! |
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[1601] | 69 | !! References : Merryfield et al., JPO, 29, 1124-1142, 1999. |
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[3] | 70 | !!---------------------------------------------------------------------- |
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[9019] | 71 | INTEGER, INTENT(in ) :: kt ! ocean time-step indexocean time step |
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| 72 | REAL(wp), DIMENSION(:,:,:), INTENT(inout) :: p_avm ! Kz on momentum (w-points) |
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| 73 | REAL(wp), DIMENSION(:,:,:), INTENT(inout) :: p_avt ! Kz on temperature (w-points) |
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| 74 | REAL(wp), DIMENSION(:,:,:), INTENT( out) :: p_avs ! Kz on salinity (w-points) |
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[2715] | 75 | ! |
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[1601] | 76 | INTEGER :: ji, jj , jk ! dummy loop indices |
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[4990] | 77 | REAL(wp) :: zaw, zbw, zrw ! local scalars |
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| 78 | REAL(wp) :: zdt, zds |
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| 79 | REAL(wp) :: zinr, zrr ! - - |
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| 80 | REAL(wp) :: zavft, zavfs ! - - |
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| 81 | REAL(wp) :: zavdt, zavds ! - - |
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[9019] | 82 | REAL(wp), DIMENSION(jpi,jpj) :: zrau, zmsks, zmskf, zmskd1, zmskd2, zmskd3 |
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[3] | 83 | !!---------------------------------------------------------------------- |
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[3294] | 84 | ! |
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[9019] | 85 | IF( ln_timing ) CALL timing_start('zdf_ddm') |
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[3294] | 86 | ! |
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[3] | 87 | ! ! =============== |
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| 88 | DO jk = 2, jpkm1 ! Horizontal slab |
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| 89 | ! ! =============== |
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| 90 | ! Define the mask |
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| 91 | ! --------------- |
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[9019] | 92 | !!gm WORK to be done: change the code from vector optimisation to scalar one. |
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| 93 | !!gm ==>>> test in the loop instead of use of mask arrays |
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| 94 | !!gm and many acces in memory |
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| 95 | |
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| 96 | DO jj = 1, jpj !== R=zrau = (alpha / beta) (dk[t] / dk[s]) ==! |
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[4990] | 97 | DO ji = 1, jpi |
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[6140] | 98 | zrw = ( gdepw_n(ji,jj,jk ) - gdept_n(ji,jj,jk) ) & |
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[9019] | 99 | !!gm please, use e3w_n below |
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[6140] | 100 | & / ( gdept_n(ji,jj,jk-1) - gdept_n(ji,jj,jk) ) |
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[4990] | 101 | ! |
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| 102 | zaw = ( rab_n(ji,jj,jk,jp_tem) * (1. - zrw) + rab_n(ji,jj,jk-1,jp_tem) * zrw ) & |
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| 103 | & * tmask(ji,jj,jk) * tmask(ji,jj,jk-1) |
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| 104 | zbw = ( rab_n(ji,jj,jk,jp_sal) * (1. - zrw) + rab_n(ji,jj,jk-1,jp_sal) * zrw ) & |
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| 105 | & * tmask(ji,jj,jk) * tmask(ji,jj,jk-1) |
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| 106 | ! |
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| 107 | zdt = zaw * ( tsn(ji,jj,jk-1,jp_tem) - tsn(ji,jj,jk,jp_tem) ) |
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| 108 | zds = zbw * ( tsn(ji,jj,jk-1,jp_sal) - tsn(ji,jj,jk,jp_sal) ) |
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| 109 | IF( ABS( zds) <= 1.e-20_wp ) zds = 1.e-20_wp |
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| 110 | zrau(ji,jj) = MAX( 1.e-20, zdt / zds ) ! only retains positive value of zrau |
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| 111 | END DO |
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| 112 | END DO |
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[3] | 113 | |
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[9019] | 114 | DO jj = 1, jpj !== indicators ==! |
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[3] | 115 | DO ji = 1, jpi |
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| 116 | ! stability indicator: msks=1 if rn2>0; 0 elsewhere |
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[2715] | 117 | IF( rn2(ji,jj,jk) + 1.e-12 <= 0. ) THEN ; zmsks(ji,jj) = 0._wp |
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| 118 | ELSE ; zmsks(ji,jj) = 1._wp |
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[3] | 119 | ENDIF |
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[4990] | 120 | ! salt fingering indicator: msksf=1 if R>1; 0 elsewhere |
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| 121 | IF( zrau(ji,jj) <= 1. ) THEN ; zmskf(ji,jj) = 0._wp |
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[2715] | 122 | ELSE ; zmskf(ji,jj) = 1._wp |
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[3] | 123 | ENDIF |
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| 124 | ! diffusive layering indicators: |
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[4990] | 125 | ! ! mskdl1=1 if 0< R <1; 0 elsewhere |
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| 126 | IF( zrau(ji,jj) >= 1. ) THEN ; zmskd1(ji,jj) = 0._wp |
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[2715] | 127 | ELSE ; zmskd1(ji,jj) = 1._wp |
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[3] | 128 | ENDIF |
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[4990] | 129 | ! ! mskdl2=1 if 0< R <0.5; 0 elsewhere |
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| 130 | IF( zrau(ji,jj) >= 0.5 ) THEN ; zmskd2(ji,jj) = 0._wp |
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[2715] | 131 | ELSE ; zmskd2(ji,jj) = 1._wp |
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[3] | 132 | ENDIF |
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[4990] | 133 | ! mskdl3=1 if 0.5< R <1; 0 elsewhere |
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| 134 | IF( zrau(ji,jj) <= 0.5 .OR. zrau(ji,jj) >= 1. ) THEN ; zmskd3(ji,jj) = 0._wp |
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| 135 | ELSE ; zmskd3(ji,jj) = 1._wp |
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[3] | 136 | ENDIF |
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| 137 | END DO |
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| 138 | END DO |
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| 139 | ! mask zmsk in order to have avt and avs masked |
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[7753] | 140 | zmsks(:,:) = zmsks(:,:) * wmask(:,:,jk) |
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[3] | 141 | |
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| 142 | |
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| 143 | ! Update avt and avs |
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| 144 | ! ------------------ |
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| 145 | ! Constant eddy coefficient: reset to the background value |
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| 146 | DO jj = 1, jpj |
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| 147 | DO ji = 1, jpi |
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[4990] | 148 | zinr = 1._wp / zrau(ji,jj) |
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[3] | 149 | ! salt fingering |
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[4990] | 150 | zrr = zrau(ji,jj) / rn_hsbfr |
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[3] | 151 | zrr = zrr * zrr |
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[1601] | 152 | zavfs = rn_avts / ( 1 + zrr*zrr*zrr ) * zmsks(ji,jj) * zmskf(ji,jj) |
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[1163] | 153 | zavft = 0.7 * zavfs * zinr |
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[3] | 154 | ! diffusive layering |
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[1601] | 155 | zavdt = 1.3635e-6 * EXP( 4.6 * EXP( -0.54*(zinr-1.) ) ) * zmsks(ji,jj) * zmskd1(ji,jj) |
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[4990] | 156 | zavds = zavdt * zmsks(ji,jj) * ( ( 1.85 * zrau(ji,jj) - 0.85 ) * zmskd3(ji,jj) & |
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| 157 | & + 0.15 * zrau(ji,jj) * zmskd2(ji,jj) ) |
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[3] | 158 | ! add to the eddy viscosity coef. previously computed |
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[9019] | 159 | p_avs(ji,jj,jk) = p_avt(ji,jj,jk) + zavfs + zavds |
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| 160 | p_avt(ji,jj,jk) = p_avt(ji,jj,jk) + zavft + zavdt |
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| 161 | p_avm(ji,jj,jk) = p_avm(ji,jj,jk) + MAX( zavft + zavdt, zavfs + zavds ) |
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[3] | 162 | END DO |
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| 163 | END DO |
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| 164 | ! ! =============== |
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| 165 | END DO ! End of slab |
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| 166 | ! ! =============== |
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[1601] | 167 | ! |
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[258] | 168 | IF(ln_ctl) THEN |
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| 169 | CALL prt_ctl(tab3d_1=avt , clinfo1=' ddm - t: ', tab3d_2=avs , clinfo2=' s: ', ovlap=1, kdim=jpk) |
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[49] | 170 | ENDIF |
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[1601] | 171 | ! |
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[9019] | 172 | IF( ln_timing ) CALL timing_stop('zdf_ddm') |
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[2715] | 173 | ! |
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[3] | 174 | END SUBROUTINE zdf_ddm |
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| 175 | |
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| 176 | !!====================================================================== |
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| 177 | END MODULE zdfddm |
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