[3] | 1 | MODULE trasbc |
---|
| 2 | !!============================================================================== |
---|
| 3 | !! *** MODULE trasbc *** |
---|
| 4 | !! Ocean active tracers: surface boundary condition |
---|
| 5 | !!============================================================================== |
---|
[503] | 6 | !! History : 8.2 ! 98-10 (G. Madec, G. Roullet, M. Imbard) Original code |
---|
| 7 | !! 8.2 ! 01-02 (D. Ludicone) sea ice and free surface |
---|
| 8 | !! 8.5 ! 02-06 (G. Madec) F90: Free form and module |
---|
[3] | 9 | !!---------------------------------------------------------------------- |
---|
[503] | 10 | |
---|
| 11 | !!---------------------------------------------------------------------- |
---|
[3] | 12 | !! tra_sbc : update the tracer trend at ocean surface |
---|
| 13 | !!---------------------------------------------------------------------- |
---|
| 14 | USE oce ! ocean dynamics and active tracers |
---|
[888] | 15 | USE sbc_oce ! surface boundary condition: ocean |
---|
[3] | 16 | USE dom_oce ! ocean space domain variables |
---|
| 17 | USE phycst ! physical constant |
---|
[216] | 18 | USE traqsr ! solar radiation penetration |
---|
| 19 | USE trdmod ! ocean trends |
---|
| 20 | USE trdmod_oce ! ocean variables trends |
---|
[3] | 21 | USE in_out_manager ! I/O manager |
---|
[258] | 22 | USE prtctl ! Print control |
---|
[3] | 23 | |
---|
| 24 | IMPLICIT NONE |
---|
| 25 | PRIVATE |
---|
| 26 | |
---|
[503] | 27 | PUBLIC tra_sbc ! routine called by step.F90 |
---|
[3] | 28 | |
---|
| 29 | !! * Substitutions |
---|
| 30 | # include "domzgr_substitute.h90" |
---|
| 31 | # include "vectopt_loop_substitute.h90" |
---|
| 32 | !!---------------------------------------------------------------------- |
---|
[247] | 33 | !! OPA 9.0 , LOCEAN-IPSL (2005) |
---|
[888] | 34 | !! $Id$ |
---|
[503] | 35 | !! Software governed by the CeCILL licence (modipsl/doc/NEMO_CeCILL.txt) |
---|
[3] | 36 | !!---------------------------------------------------------------------- |
---|
| 37 | |
---|
| 38 | CONTAINS |
---|
| 39 | |
---|
| 40 | SUBROUTINE tra_sbc ( kt ) |
---|
| 41 | !!---------------------------------------------------------------------- |
---|
| 42 | !! *** ROUTINE tra_sbc *** |
---|
| 43 | !! |
---|
| 44 | !! ** Purpose : Compute the tracer surface boundary condition trend of |
---|
| 45 | !! (flux through the interface, concentration/dilution effect) |
---|
| 46 | !! and add it to the general trend of tracer equations. |
---|
| 47 | !! |
---|
| 48 | !! ** Method : |
---|
[664] | 49 | !! Following Roullet and Madec (2000), the air-sea flux can be divided |
---|
| 50 | !! into three effects: (1) Fext, external forcing; |
---|
| 51 | !! (2) Fwi, concentration/dilution effect due to water exchanged |
---|
| 52 | !! at the surface by evaporation, precipitations and runoff (E-P-R); |
---|
| 53 | !! (3) Fwe, tracer carried with the water that is exchanged. |
---|
| 54 | !! |
---|
| 55 | !! Fext, flux through the air-sea interface for temperature and salt: |
---|
[3] | 56 | !! - temperature : heat flux q (w/m2). If penetrative solar |
---|
| 57 | !! radiation q is only the non solar part of the heat flux, the |
---|
| 58 | !! solar part is added in traqsr.F routine. |
---|
| 59 | !! ta = ta + q /(rau0 rcp e3t) for k=1 |
---|
| 60 | !! - salinity : no salt flux |
---|
[664] | 61 | !! |
---|
| 62 | !! The formulation for Fwb and Fwi vary according to the free |
---|
| 63 | !! surface formulation (linear or variable volume). |
---|
| 64 | !! * Linear free surface |
---|
| 65 | !! The surface freshwater flux modifies the ocean volume |
---|
[3] | 66 | !! and thus the concentration of a tracer and the temperature. |
---|
| 67 | !! First order of the effect of surface freshwater exchange |
---|
| 68 | !! for salinity, it can be neglected on temperature (especially |
---|
[664] | 69 | !! as the temperature of precipitations and runoffs is usually |
---|
| 70 | !! unknown). |
---|
[3] | 71 | !! - temperature : we assume that the temperature of both |
---|
| 72 | !! precipitations and runoffs is equal to the SST, thus there |
---|
| 73 | !! is no additional flux since in this case, the concentration |
---|
| 74 | !! dilution effect is balanced by the net heat flux associated |
---|
[664] | 75 | !! to the freshwater exchange (Fwe+Fwi=0): |
---|
| 76 | !! (Tp P - Te E) + SST (P-E) = 0 when Tp=Te=SST |
---|
[3] | 77 | !! - salinity : evaporation, precipitation and runoff |
---|
[664] | 78 | !! water has a zero salinity (Fwe=0), thus only Fwi remains: |
---|
[3] | 79 | !! sa = sa + emp * sn / e3t for k=1 |
---|
| 80 | !! where emp, the surface freshwater budget (evaporation minus |
---|
| 81 | !! precipitation minus runoff) given in kg/m2/s is divided |
---|
[664] | 82 | !! by 1000 kg/m3 (density of plain water) to obtain m/s. |
---|
| 83 | !! Note: even though Fwe does not appear explicitly for |
---|
| 84 | !! temperature in this routine, the heat carried by the water |
---|
| 85 | !! exchanged through the surface is part of the total heat flux |
---|
| 86 | !! forcing and must be taken into account in the global heat |
---|
| 87 | !! balance). |
---|
| 88 | !! * nonlinear free surface (variable volume, lk_vvl) |
---|
| 89 | !! contrary to the linear free surface case, Fwi is properly |
---|
| 90 | !! taken into account by using the true layer thicknesses to |
---|
| 91 | !! calculate tracer content and advection. There is no need to |
---|
| 92 | !! deal with it in this routine. |
---|
| 93 | !! - temperature: Fwe=SST (P-E+R) is added to Fext. |
---|
| 94 | !! - salinity: Fwe = 0, there is no surface flux of salt. |
---|
[3] | 95 | !! |
---|
| 96 | !! ** Action : - Update the 1st level of (ta,sa) with the trend associated |
---|
| 97 | !! with the tracer surface boundary condition |
---|
| 98 | !! - save the trend it in ttrd ('key_trdtra') |
---|
[503] | 99 | !!---------------------------------------------------------------------- |
---|
| 100 | USE oce, ONLY : ztrdt => ua ! use ua as 3D workspace |
---|
| 101 | USE oce, ONLY : ztrds => va ! use va as 3D workspace |
---|
[3] | 102 | !! |
---|
[503] | 103 | INTEGER, INTENT(in) :: kt ! ocean time-step index |
---|
| 104 | !! |
---|
[3] | 105 | INTEGER :: ji, jj ! dummy loop indices |
---|
| 106 | REAL(wp) :: zta, zsa, zsrau, zse3t ! temporary scalars |
---|
| 107 | !!---------------------------------------------------------------------- |
---|
| 108 | |
---|
| 109 | IF( kt == nit000 ) THEN |
---|
| 110 | IF(lwp) WRITE(numout,*) |
---|
| 111 | IF(lwp) WRITE(numout,*) 'tra_sbc : TRAcer Surface Boundary Condition' |
---|
| 112 | IF(lwp) WRITE(numout,*) '~~~~~~~ ' |
---|
| 113 | ENDIF |
---|
| 114 | |
---|
[503] | 115 | zsrau = 1. / rauw ! initialization |
---|
[457] | 116 | #if defined key_zco |
---|
| 117 | zse3t = 1. / e3t_0(1) |
---|
[3] | 118 | #endif |
---|
| 119 | |
---|
[503] | 120 | IF( l_trdtra ) THEN ! Save ta and sa trends |
---|
| 121 | ztrdt(:,:,:) = ta(:,:,:) |
---|
| 122 | ztrds(:,:,:) = sa(:,:,:) |
---|
[216] | 123 | ENDIF |
---|
| 124 | |
---|
[3] | 125 | IF( .NOT.ln_traqsr ) qsr(:,:) = 0.e0 ! no solar radiation penetration |
---|
| 126 | |
---|
[503] | 127 | ! Concentration dillution effect on (t,s) |
---|
[3] | 128 | DO jj = 2, jpj |
---|
| 129 | DO ji = fs_2, fs_jpim1 ! vector opt. |
---|
[457] | 130 | #if ! defined key_zco |
---|
[3] | 131 | zse3t = 1. / fse3t(ji,jj,1) |
---|
| 132 | #endif |
---|
[592] | 133 | IF( lk_vvl) THEN |
---|
[888] | 134 | zta = ro0cpr * qns(ji,jj) * zse3t & ! temperature : heat flux |
---|
[592] | 135 | & - emp(ji,jj) * zsrau * tn(ji,jj,1) * zse3t ! & cooling/heating effet of EMP flux |
---|
| 136 | zsa = 0.e0 ! No salinity concent./dilut. effect |
---|
| 137 | ELSE |
---|
[888] | 138 | zta = ro0cpr * qns(ji,jj) * zse3t ! temperature : heat flux |
---|
[592] | 139 | zsa = emps(ji,jj) * zsrau * sn(ji,jj,1) * zse3t ! salinity : concent./dilut. effect |
---|
| 140 | ENDIF |
---|
| 141 | ta(ji,jj,1) = ta(ji,jj,1) + zta ! add the trend to the general tracer trend |
---|
[3] | 142 | sa(ji,jj,1) = sa(ji,jj,1) + zsa |
---|
| 143 | END DO |
---|
| 144 | END DO |
---|
[216] | 145 | |
---|
[503] | 146 | IF( l_trdtra ) THEN ! save the sbc trends for diagnostic |
---|
| 147 | ztrdt(:,:,:) = ta(:,:,:) - ztrdt(:,:,:) |
---|
| 148 | ztrds(:,:,:) = sa(:,:,:) - ztrds(:,:,:) |
---|
| 149 | CALL trd_mod(ztrdt, ztrds, jptra_trd_nsr, 'TRA', kt) |
---|
[216] | 150 | ENDIF |
---|
[503] | 151 | ! |
---|
| 152 | IF(ln_ctl) CALL prt_ctl( tab3d_1=ta, clinfo1=' sbc - Ta: ', mask1=tmask, & |
---|
| 153 | & tab3d_2=sa, clinfo2= ' Sa: ', mask2=tmask, clinfo3='tra' ) |
---|
| 154 | ! |
---|
[3] | 155 | END SUBROUTINE tra_sbc |
---|
| 156 | |
---|
| 157 | !!====================================================================== |
---|
| 158 | END MODULE trasbc |
---|