| 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 | !! History : OPA ! 1998-10 (G. Madec, G. Roullet, M. Imbard) Original code |
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| 7 | !! 8.2 ! 2001-02 (D. Ludicone) sea ice and free surface |
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| 8 | !! NEMO 1.0 ! 2002-06 (G. Madec) F90: Free form and module |
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| 9 | !! 3.3 ! 2010-04 (M. Leclair, G. Madec) Forcing averaged over 2 time steps |
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| 10 | !! - ! 2010-09 (C. Ethe, G. Madec) Merge TRA-TRC |
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| 11 | !!---------------------------------------------------------------------- |
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| 12 | |
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| 13 | !!---------------------------------------------------------------------- |
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| 14 | !! tra_sbc : update the tracer trend at ocean surface |
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| 15 | !!---------------------------------------------------------------------- |
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| 16 | USE oce ! ocean dynamics and active tracers |
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| 17 | USE sbc_oce ! surface boundary condition: ocean |
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| 18 | USE dom_oce ! ocean space domain variables |
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| 19 | USE phycst ! physical constant |
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| 20 | USE traqsr ! solar radiation penetration |
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| 21 | USE trdmod_oce ! ocean trends |
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| 22 | USE trdtra ! ocean trends |
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| 23 | USE in_out_manager ! I/O manager |
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| 24 | USE prtctl ! Print control |
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| 25 | USE restart ! ocean restart |
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| 26 | USE sbcrnf ! River runoff |
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| 27 | USE sbcmod ! ln_rnf |
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| 28 | USE iom |
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| 29 | USE lbclnk ! ocean lateral boundary conditions (or mpp link) |
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| 30 | |
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| 31 | IMPLICIT NONE |
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| 32 | PRIVATE |
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| 33 | |
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| 34 | PUBLIC tra_sbc ! routine called by step.F90 |
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| 35 | |
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| 36 | !! * Substitutions |
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| 37 | # include "domzgr_substitute.h90" |
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| 38 | # include "vectopt_loop_substitute.h90" |
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| 39 | !!---------------------------------------------------------------------- |
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| 40 | !! NEMO/OPA 3.3 , NEMO Consortium (2010) |
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| 41 | !! $Id$ |
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| 42 | !! Software governed by the CeCILL licence (NEMOGCM/NEMO_CeCILL.txt) |
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| 43 | !!---------------------------------------------------------------------- |
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| 44 | CONTAINS |
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| 45 | |
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| 46 | SUBROUTINE tra_sbc ( kt ) |
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| 47 | !!---------------------------------------------------------------------- |
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| 48 | !! *** ROUTINE tra_sbc *** |
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| 49 | !! |
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| 50 | !! ** Purpose : Compute the tracer surface boundary condition trend of |
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| 51 | !! (flux through the interface, concentration/dilution effect) |
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| 52 | !! and add it to the general trend of tracer equations. |
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| 53 | !! |
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| 54 | !! ** Method : |
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| 55 | !! Following Roullet and Madec (2000), the air-sea flux can be divided |
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| 56 | !! into three effects: (1) Fext, external forcing; |
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| 57 | !! (2) Fwi, concentration/dilution effect due to water exchanged |
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| 58 | !! at the surface by evaporation, precipitations and runoff (E-P-R); |
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| 59 | !! (3) Fwe, tracer carried with the water that is exchanged. |
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| 60 | !! |
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| 61 | !! Fext, flux through the air-sea interface for temperature and salt: |
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| 62 | !! - temperature : heat flux q (w/m2). If penetrative solar |
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| 63 | !! radiation q is only the non solar part of the heat flux, the |
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| 64 | !! solar part is added in traqsr.F routine. |
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| 65 | !! ta = ta + q /(rau0 rcp e3t) for k=1 |
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| 66 | !! - salinity : no salt flux |
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| 67 | !! |
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| 68 | !! The formulation for Fwb and Fwi vary according to the free |
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| 69 | !! surface formulation (linear or variable volume). |
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| 70 | !! * Linear free surface |
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| 71 | !! The surface freshwater flux modifies the ocean volume |
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| 72 | !! and thus the concentration of a tracer and the temperature. |
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| 73 | !! First order of the effect of surface freshwater exchange |
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| 74 | !! for salinity, it can be neglected on temperature (especially |
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| 75 | !! as the temperature of precipitations and runoffs is usually |
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| 76 | !! unknown). |
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| 77 | !! - temperature : we assume that the temperature of both |
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| 78 | !! precipitations and runoffs is equal to the SST, thus there |
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| 79 | !! is no additional flux since in this case, the concentration |
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| 80 | !! dilution effect is balanced by the net heat flux associated |
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| 81 | !! to the freshwater exchange (Fwe+Fwi=0): |
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| 82 | !! (Tp P - Te E) + SST (P-E) = 0 when Tp=Te=SST |
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| 83 | !! - salinity : evaporation, precipitation and runoff |
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| 84 | !! water has a zero salinity (Fwe=0), thus only Fwi remains: |
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| 85 | !! sa = sa + emp * sn / e3t for k=1 |
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| 86 | !! where emp, the surface freshwater budget (evaporation minus |
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| 87 | !! precipitation minus runoff) given in kg/m2/s is divided |
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| 88 | !! by 1035 kg/m3 (density of ocena water) to obtain m/s. |
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| 89 | !! Note: even though Fwe does not appear explicitly for |
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| 90 | !! temperature in this routine, the heat carried by the water |
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| 91 | !! exchanged through the surface is part of the total heat flux |
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| 92 | !! forcing and must be taken into account in the global heat |
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| 93 | !! balance). |
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| 94 | !! * nonlinear free surface (variable volume, lk_vvl) |
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| 95 | !! contrary to the linear free surface case, Fwi is properly |
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| 96 | !! taken into account by using the true layer thicknesses to |
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| 97 | !! calculate tracer content and advection. There is no need to |
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| 98 | !! deal with it in this routine. |
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| 99 | !! - temperature: Fwe=SST (P-E+R) is added to Fext. |
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| 100 | !! - salinity: Fwe = 0, there is no surface flux of salt. |
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| 101 | !! |
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| 102 | !! ** Action : - Update the 1st level of (ta,sa) with the trend associated |
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| 103 | !! with the tracer surface boundary condition |
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| 104 | !! - save the trend it in ttrd ('key_trdtra') |
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| 105 | !!---------------------------------------------------------------------- |
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| 106 | INTEGER, INTENT(in) :: kt ! ocean time-step index |
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| 107 | !! |
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| 108 | INTEGER :: ji, jj, jk, jn ! dummy loop indices |
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| 109 | REAL(wp) :: zfact, z1_e3t, zsrau, zdep |
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| 110 | REAL(wp), DIMENSION(:,:,:), ALLOCATABLE :: ztrdt, ztrds |
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| 111 | !!---------------------------------------------------------------------- |
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| 112 | |
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| 113 | IF( kt == nit000 ) THEN |
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| 114 | IF(lwp) WRITE(numout,*) |
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| 115 | IF(lwp) WRITE(numout,*) 'tra_sbc : TRAcer Surface Boundary Condition' |
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| 116 | IF(lwp) WRITE(numout,*) '~~~~~~~ ' |
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| 117 | ENDIF |
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| 118 | |
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| 119 | zsrau = 1. / rau0 ! initialization |
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| 120 | |
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| 121 | IF( l_trdtra ) THEN !* Save ta and sa trends |
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| 122 | ALLOCATE( ztrdt(jpi,jpj,jpk) ) ; ztrdt(:,:,:) = tsa(:,:,:,jp_tem) |
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| 123 | ALLOCATE( ztrds(jpi,jpj,jpk) ) ; ztrds(:,:,:) = tsa(:,:,:,jp_sal) |
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| 124 | ENDIF |
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| 125 | |
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| 126 | !!gm IF( .NOT.ln_traqsr ) qsr(:,:) = 0.e0 ! no solar radiation penetration |
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| 127 | IF( .NOT.ln_traqsr ) THEN ! no solar radiation penetration |
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| 128 | qns(:,:) = qns(:,:) + qsr(:,:) ! total heat flux in qns |
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| 129 | qsr(:,:) = 0.e0 ! qsr set to zero |
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| 130 | ENDIF |
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| 131 | |
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| 132 | !---------------------------------------- |
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| 133 | ! EMP, EMPS and QNS effects |
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| 134 | !---------------------------------------- |
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| 135 | ! Set before sbc tracer content fields |
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| 136 | ! ************************************ |
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| 137 | IF( kt == nit000 ) THEN ! Set the forcing field at nit000 - 1 |
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| 138 | ! ! ----------------------------------- |
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| 139 | IF( ln_rstart .AND. & ! Restart: read in restart file |
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| 140 | & iom_varid( numror, 'sbc_hc_b', ldstop = .FALSE. ) > 0 ) THEN |
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| 141 | IF(lwp) WRITE(numout,*) ' nit000-1 surface tracer content forcing fields red in the restart file' |
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| 142 | zfact = 0.5e0 |
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| 143 | CALL iom_get( numror, jpdom_autoglo, 'sbc_hc_b', sbc_tsc_b(:,:,jp_tem) ) ! before heat content sbc trend |
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| 144 | CALL iom_get( numror, jpdom_autoglo, 'sbc_sc_b', sbc_tsc_b(:,:,jp_sal) ) ! before salt content sbc trend |
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| 145 | ELSE ! No restart or restart not found: Euler forward time stepping |
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| 146 | zfact = 1.e0 |
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| 147 | sbc_tsc_b(:,:,:) = 0.e0 |
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| 148 | ENDIF |
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| 149 | ELSE ! Swap of forcing fields |
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| 150 | ! ! ---------------------- |
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| 151 | zfact = 0.5e0 |
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| 152 | sbc_tsc_b(:,:,:) = sbc_tsc(:,:,:) |
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| 153 | ENDIF |
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| 154 | ! Compute now sbc tracer content fields |
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| 155 | ! ************************************* |
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| 156 | |
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| 157 | ! Concentration dilution effect on (t,s) due to |
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| 158 | ! evaporation, precipitation and qns, but not river runoff |
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| 159 | |
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| 160 | IF( lk_vvl ) THEN ! Variable Volume case |
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| 161 | DO jj = 2, jpj |
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| 162 | DO ji = fs_2, fs_jpim1 ! vector opt. |
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| 163 | ! temperature : heat flux + cooling/heating effet of EMP flux |
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| 164 | sbc_tsc(ji,jj,jp_tem) = ro0cpr * qns(ji,jj) - zsrau * emp(ji,jj) * tsn(ji,jj,1,jp_tem) |
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| 165 | ! concent./dilut. effect due to sea-ice melt/formation and (possibly) SSS restoration |
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| 166 | sbc_tsc(ji,jj,jp_sal) = ( emps(ji,jj) - emp(ji,jj) ) * zsrau * tsn(ji,jj,1,jp_sal) |
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| 167 | END DO |
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| 168 | END DO |
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| 169 | ELSE ! Constant Volume case |
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| 170 | DO jj = 2, jpj |
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| 171 | DO ji = fs_2, fs_jpim1 ! vector opt. |
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| 172 | ! temperature : heat flux |
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| 173 | sbc_tsc(ji,jj,jp_tem) = ro0cpr * qns(ji,jj) |
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| 174 | ! salinity : salt flux + concent./dilut. effect (both in emps) |
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| 175 | sbc_tsc(ji,jj,jp_sal) = zsrau * emps(ji,jj) * tsn(ji,jj,1,jp_sal) |
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| 176 | END DO |
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| 177 | END DO |
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| 178 | ENDIF |
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| 179 | ! Concentration dilution effect on (t,s) due to evapouration, precipitation and qns, but not river runoff |
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| 180 | DO jn = 1, jpts |
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| 181 | DO jj = 2, jpj |
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| 182 | DO ji = fs_2, fs_jpim1 ! vector opt. |
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| 183 | z1_e3t = zfact / fse3t(ji,jj,1) |
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| 184 | tsa(ji,jj,1,jn) = tsa(ji,jj,1,jn) + ( sbc_tsc_b(ji,jj,jn) + sbc_tsc(ji,jj,jn) ) * z1_e3t |
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| 185 | END DO |
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| 186 | END DO |
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| 187 | END DO |
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| 188 | ! Write in the ocean restart file |
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| 189 | ! ******************************* |
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| 190 | IF( lrst_oce ) THEN |
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| 191 | IF(lwp) WRITE(numout,*) |
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| 192 | IF(lwp) WRITE(numout,*) 'sbc : ocean surface tracer content forcing fields written in ocean restart file ', & |
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| 193 | & 'at it= ', kt,' date= ', ndastp |
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| 194 | IF(lwp) WRITE(numout,*) '~~~~' |
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| 195 | CALL iom_rstput( kt, nitrst, numrow, 'sbc_hc_b', sbc_tsc(:,:,jp_tem) ) |
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| 196 | CALL iom_rstput( kt, nitrst, numrow, 'sbc_sc_b', sbc_tsc(:,:,jp_sal) ) |
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| 197 | ENDIF |
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| 198 | ! |
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| 199 | !---------------------------------------- |
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| 200 | ! River Runoff effects |
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| 201 | !---------------------------------------- |
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| 202 | ! |
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| 203 | zfact = 0.5e0 |
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| 204 | |
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| 205 | ! Effect on (t,s) due to river runoff (dilution effect automatically applied via vertical tracer advection) |
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| 206 | IF( ln_rnf ) THEN |
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| 207 | DO jj = 2, jpj |
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| 208 | DO ji = fs_2, fs_jpim1 |
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| 209 | zdep = 1. / h_rnf(ji,jj) |
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| 210 | zdep = zfact * zdep |
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| 211 | IF ( rnf(ji,jj) /= 0._wp ) THEN |
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| 212 | DO jk = 1, nk_rnf(ji,jj) |
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| 213 | tsa(ji,jj,jk,jp_tem) = tsa(ji,jj,jk,jp_tem) & |
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| 214 | & + ( rnf_tsc_b(ji,jj,jp_tem) + rnf_tsc(ji,jj,jp_tem) ) * zdep |
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| 215 | IF( ln_rnf_sal ) tsa(ji,jj,jk,jp_sal) = tsa(ji,jj,jk,jp_sal) & |
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| 216 | & + ( rnf_tsc_b(ji,jj,jp_sal) + rnf_tsc(ji,jj,jp_sal) ) * zdep |
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| 217 | END DO |
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| 218 | ENDIF |
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| 219 | END DO |
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| 220 | END DO |
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| 221 | ENDIF |
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| 222 | !!gm It should be useless |
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| 223 | CALL lbc_lnk( tsa(:,:,:,jp_tem), 'T', 1. ) ; CALL lbc_lnk( tsa(:,:,:,jp_sal), 'T', 1. ) |
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| 224 | |
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| 225 | IF( l_trdtra ) THEN ! save the horizontal diffusive trends for further diagnostics |
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| 226 | ztrdt(:,:,:) = tsa(:,:,:,jp_tem) - ztrdt(:,:,:) |
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| 227 | ztrds(:,:,:) = tsa(:,:,:,jp_sal) - ztrds(:,:,:) |
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| 228 | CALL trd_tra( kt, 'TRA', jp_tem, jptra_trd_nsr, ztrdt ) |
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| 229 | CALL trd_tra( kt, 'TRA', jp_sal, jptra_trd_nsr, ztrds ) |
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| 230 | DEALLOCATE( ztrdt ) ; DEALLOCATE( ztrds ) |
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| 231 | ENDIF |
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| 232 | ! |
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| 233 | IF(ln_ctl) CALL prt_ctl( tab3d_1=tsa(:,:,:,jp_tem), clinfo1=' sbc - Ta: ', mask1=tmask, & |
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| 234 | & tab3d_2=tsa(:,:,:,jp_sal), clinfo2= ' Sa: ', mask2=tmask, clinfo3='tra' ) |
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| 235 | ! |
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| 236 | END SUBROUTINE tra_sbc |
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| 237 | |
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| 238 | !!====================================================================== |
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| 239 | END MODULE trasbc |
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