MODULE zdfbfr !!====================================================================== !! *** MODULE zdfbfr *** !! Ocean physics: Bottom friction !!====================================================================== !! History : OPA ! 1997-06 (G. Madec, A.-M. Treguier) Original code !! NEMO 1.0 ! 2002-06 (G. Madec) F90: Free form and module !! 3.2 ! 2009-09 (A.C.Coward) Correction to include barotropic contribution !! 3.3 ! 2010-10 (C. Ethe, G. Madec) reorganisation of initialisation phase !! 3.4 ! 2011-11 (H. Liu) implementation of semi-implicit bottom friction option !! ! 2012-06 (H. Liu) implementation of Log Layer bottom friction option !!---------------------------------------------------------------------- !!---------------------------------------------------------------------- !! zdf_bfr : update momentum Kz at the ocean bottom due to the type of bottom friction chosen !! zdf_bfr_init : read in namelist and control the bottom friction parameters. !! zdf_bfr_2d : read in namelist and control the bottom friction parameters. !!---------------------------------------------------------------------- USE oce ! ocean dynamics and tracers variables USE dom_oce ! ocean space and time domain variables USE zdf_oce ! ocean vertical physics variables USE in_out_manager ! I/O manager USE lbclnk ! ocean lateral boundary conditions (or mpp link) USE lib_mpp ! distributed memory computing USE prtctl ! Print control USE timing ! Timing USE phycst, ONLY: vkarmn IMPLICIT NONE PRIVATE PUBLIC zdf_bfr ! called by step.F90 PUBLIC zdf_bfr_init ! called by opa.F90 ! !!* Namelist nambfr: bottom friction namelist * INTEGER , PUBLIC :: nn_bfr = 0 ! = 0/1/2/3 type of bottom friction (PUBLIC for TAM) REAL(wp), PUBLIC :: rn_bfri1 = 4.0e-4_wp ! bottom drag coefficient (linear case) (PUBLIC for TAM) REAL(wp), PUBLIC :: rn_bfri2 = 1.0e-3_wp ! bottom drag coefficient (non linear case) (PUBLIC for TAM) REAL(wp), PUBLIC :: rn_bfeb2 = 2.5e-3_wp ! background bottom turbulent kinetic energy [m2/s2] (PUBLIC for TAM) REAL(wp), PUBLIC :: rn_bfrien = 30._wp ! local factor to enhance coefficient bfri (PUBLIC for TAM) LOGICAL , PUBLIC :: ln_bfr2d = .false. ! logical switch for 2D enhancement (PUBLIC for TAM) LOGICAL , PUBLIC :: ln_loglayer = .false. ! switch for log layer bfr coeff. (PUBLIC for TAM) REAL(wp), PUBLIC :: rn_bfrz0 = 0.003_wp ! bottom roughness for loglayer bfr coeff (PUBLIC for TAM) LOGICAL , PUBLIC :: ln_bfrimp = .false. ! logical switch for implicit bottom friction REAL(wp), ALLOCATABLE, SAVE, DIMENSION(:,:), PUBLIC :: bfrcoef2d ! 2D bottom drag coefficient (PUBLIC for TAM) !! * Substitutions # include "vectopt_loop_substitute.h90" # include "domzgr_substitute.h90" !!---------------------------------------------------------------------- !! NEMO/OPA 4.0 , NEMO Consortium (2011) !! $Id$ !! Software governed by the CeCILL licence (NEMOGCM/NEMO_CeCILL.txt) !!---------------------------------------------------------------------- CONTAINS INTEGER FUNCTION zdf_bfr_alloc() !!---------------------------------------------------------------------- !! *** FUNCTION zdf_bfr_alloc *** !!---------------------------------------------------------------------- ALLOCATE( bfrcoef2d(jpi,jpj), STAT=zdf_bfr_alloc ) ! IF( lk_mpp ) CALL mpp_sum ( zdf_bfr_alloc ) IF( zdf_bfr_alloc /= 0 ) CALL ctl_warn('zdf_bfr_alloc: failed to allocate arrays.') END FUNCTION zdf_bfr_alloc SUBROUTINE zdf_bfr( kt ) !!---------------------------------------------------------------------- !! *** ROUTINE zdf_bfr *** !! !! ** Purpose : compute the bottom friction coefficient. !! !! ** Method : Calculate and store part of the momentum trend due !! to bottom friction following the chosen friction type !! (free-slip, linear, or quadratic). The component !! calculated here is multiplied by the bottom velocity in !! dyn_bfr to provide the trend term. !! The coefficients are updated at each time step only !! in the quadratic case. !! !! ** Action : bfrua , bfrva bottom friction coefficients !!---------------------------------------------------------------------- INTEGER, INTENT( in ) :: kt ! ocean time-step index !! INTEGER :: ji, jj ! dummy loop indices INTEGER :: ikbu, ikbv ! local integers REAL(wp) :: zvu, zuv, zecu, zecv ! temporary scalars REAL(wp) :: ztmp, ztmp1 ! temporary scalars !!---------------------------------------------------------------------- ! IF( nn_timing == 1 ) CALL timing_start('zdf_bfr') ! IF( nn_bfr == 2 ) THEN ! quadratic botton friction ! Calculate and store the quadratic bottom friction coefficient bfrua and bfrva ! where bfrUa = C_d*SQRT(u_bot^2 + v_bot^2 + e_b) {U=[u,v]} ! from these the trend due to bottom friction: -F_h/e3U can be calculated ! where -F_h/e3U_bot = bfrUa*Ub/e3U_bot {U=[u,v]} ! IF(ln_loglayer) THEN ! "log layer" bottom friction coefficient ! add 2D-enhancement bottom friction ztmp1 = 1._wp IF(ABS(rn_bfri2) >= 1.e-10 ) THEN ztmp1 = 1._wp / rn_bfri2 ELSE CALL ctl_stop( 'rn_bfri2 must not be less than 1.e-10') END IF # if defined key_vectopt_loop DO jj = 1, 1 DO ji = 1, jpij ! vector opt. (forced unrolling) # else DO jj = 1, jpj DO ji = 1, jpi # endif ztmp = 0.5_wp * fse3t(ji,jj,mbkt(ji,jj)) ztmp = max(ztmp, rn_bfrz0 + 1.e-10) bfrcoef2d(ji,jj) = bfrcoef2d(ji,jj) * ztmp1 * & & ( log( ztmp / rn_bfrz0 ) / vkarmn ) ** (-2) END DO END DO ENDIF # if defined key_vectopt_loop DO jj = 1, 1 !CDIR NOVERRCHK DO ji = jpi+2, jpij-jpi-1 ! vector opt. (forced unrolling) # else !CDIR NOVERRCHK DO jj = 2, jpjm1 !CDIR NOVERRCHK DO ji = 2, jpim1 # endif ikbu = mbku(ji,jj) ! ocean bottom level at u- and v-points ikbv = mbkv(ji,jj) ! (deepest ocean u- and v-points) ! zvu = 0.25 * ( vn(ji,jj ,ikbu) + vn(ji+1,jj ,ikbu) & & + vn(ji,jj-1,ikbu) + vn(ji+1,jj-1,ikbu) ) zuv = 0.25 * ( un(ji,jj ,ikbv) + un(ji-1,jj ,ikbv) & & + un(ji,jj+1,ikbv) + un(ji-1,jj+1,ikbv) ) ! zecu = SQRT( un(ji,jj,ikbu) * un(ji,jj,ikbu) + zvu*zvu + rn_bfeb2 ) zecv = SQRT( vn(ji,jj,ikbv) * vn(ji,jj,ikbv) + zuv*zuv + rn_bfeb2 ) ! bfrua(ji,jj) = - 0.5_wp * ( bfrcoef2d(ji,jj) + bfrcoef2d(ji+1,jj ) ) * zecu bfrva(ji,jj) = - 0.5_wp * ( bfrcoef2d(ji,jj) + bfrcoef2d(ji ,jj+1) ) * zecv END DO END DO ! CALL lbc_lnk( bfrua, 'U', 1. ) ; CALL lbc_lnk( bfrva, 'V', 1. ) ! Lateral boundary condition ! IF(ln_ctl) CALL prt_ctl( tab2d_1=bfrua, clinfo1=' bfr - u: ', mask1=umask, & & tab2d_2=bfrva, clinfo2= ' v: ', mask2=vmask,ovlap=1 ) ENDIF ! IF( nn_timing == 1 ) CALL timing_stop('zdf_bfr') ! END SUBROUTINE zdf_bfr SUBROUTINE zdf_bfr_init !!---------------------------------------------------------------------- !! *** ROUTINE zdf_bfr_init *** !! !! ** Purpose : Initialization of the bottom friction !! !! ** Method : Read the nammbf namelist and check their consistency !! called at the first timestep (nit000) !!---------------------------------------------------------------------- USE iom ! I/O module for ehanced bottom friction file !! INTEGER :: inum ! logical unit for enhanced bottom friction file INTEGER :: ji, jj ! dummy loop indexes INTEGER :: ikbu, ikbv ! temporary integers INTEGER :: ictu, ictv ! - - REAL(wp) :: zminbfr, zmaxbfr ! temporary scalars REAL(wp) :: zfru, zfrv ! - - !! NAMELIST/nambfr/ nn_bfr, rn_bfri1, rn_bfri2, rn_bfeb2, rn_bfrz0, ln_bfr2d, & & rn_bfrien, ln_bfrimp, ln_loglayer !!---------------------------------------------------------------------- ! IF( nn_timing == 1 ) CALL timing_start('zdf_bfr_init') ! REWIND ( numnam ) !* Read Namelist nam_bfr : bottom momentum boundary condition READ ( numnam, nambfr ) ! !* Parameter control and print IF(lwp) WRITE(numout,*) IF(lwp) WRITE(numout,*) 'zdf_bfr : momentum bottom friction' IF(lwp) WRITE(numout,*) '~~~~~~~' IF(lwp) WRITE(numout,*) ' Namelist nam_bfr : set bottom friction parameters' ! ! allocate zdfbfr arrays IF( zdf_bfr_alloc() /= 0 ) CALL ctl_stop( 'STOP', 'zdf_bfr_init : unable to allocate arrays' ) ! ! Make sure ln_zdfexp=.false. when use implicit bfr IF( ln_bfrimp .AND. ln_zdfexp ) THEN IF(lwp) THEN WRITE(numout,*) WRITE(numout,*) 'Implicit bottom friction can only be used when ln_zdfexp=.false.' WRITE(numout,*) ' but you set: ln_bfrimp=.true. and ln_zdfexp=.true.!!!!' WRITE(ctmp1,*) ' set either ln_zdfexp = .false or ln_bfrimp = .false.' CALL ctl_stop( ctmp1 ) END IF END IF SELECT CASE (nn_bfr) ! CASE( 0 ) IF(lwp) WRITE(numout,*) ' free-slip ' bfrua(:,:) = 0.e0 bfrva(:,:) = 0.e0 ! CASE( 1 ) IF(lwp) WRITE(numout,*) ' linear botton friction' IF(lwp) WRITE(numout,*) ' friction coef. rn_bfri1 = ', rn_bfri1 IF( ln_bfr2d ) THEN IF(lwp) WRITE(numout,*) ' read coef. enhancement distribution from file ln_bfr2d = ', ln_bfr2d IF(lwp) WRITE(numout,*) ' coef rn_bfri2 enhancement factor rn_bfrien = ',rn_bfrien ENDIF ! bfrcoef2d(:,:) = rn_bfri1 ! initialize bfrcoef2d to the namelist variable ! IF(ln_bfr2d) THEN ! bfr_coef is a coefficient in [0,1] giving the mask where to apply the bfr enhancement CALL iom_open('bfr_coef.nc',inum) CALL iom_get (inum, jpdom_data, 'bfr_coef',bfrcoef2d,1) ! bfrcoef2d is used as tmp array CALL iom_close(inum) bfrcoef2d(:,:) = rn_bfri1 * ( 1 + rn_bfrien * bfrcoef2d(:,:) ) ENDIF bfrua(:,:) = - bfrcoef2d(:,:) bfrva(:,:) = - bfrcoef2d(:,:) ! CASE( 2 ) IF(lwp) WRITE(numout,*) ' quadratic botton friction' IF(lwp) WRITE(numout,*) ' friction coef. rn_bfri2 = ', rn_bfri2 IF(lwp) WRITE(numout,*) ' background tke rn_bfeb2 = ', rn_bfeb2 IF( ln_bfr2d ) THEN IF(lwp) WRITE(numout,*) ' read coef. enhancement distribution from file ln_bfr2d = ', ln_bfr2d IF(lwp) WRITE(numout,*) ' coef rn_bfri2 enhancement factor rn_bfrien = ',rn_bfrien ENDIF bfrcoef2d(:,:) = rn_bfri2 ! initialize bfrcoef2d to the namelist variable ! IF(ln_bfr2d) THEN ! bfr_coef is a coefficient in [0,1] giving the mask where to apply the bfr enhancement CALL iom_open('bfr_coef.nc',inum) CALL iom_get (inum, jpdom_data, 'bfr_coef',bfrcoef2d,1) ! bfrcoef2d is used as tmp array CALL iom_close(inum) bfrcoef2d(:,:)= rn_bfri2 * ( 1 + rn_bfrien * bfrcoef2d(:,:) ) ENDIF ! CASE DEFAULT IF(lwp) WRITE(ctmp1,*) ' bad flag value for nn_bfr = ', nn_bfr CALL ctl_stop( ctmp1 ) ! END SELECT IF( nn_bfr /= 2 .AND. ln_loglayer ) THEN IF(lwp) THEN WRITE(numout,*) WRITE(numout,*) 'Loglayer can only be by applied for quadratic bottom friction' WRITE(numout,*) 'but you have set: nn_bfr /= 2 and ln_loglayer=.true.!!!!' WRITE(ctmp1,*) 'check nn_bfr and ln_loglayer (should be 2 and true)' CALL ctl_stop( ctmp1 ) END IF END IF IF(lwp) WRITE(numout,*) ' implicit bottom friction switch ln_bfrimp = ', ln_bfrimp ! ! Basic stability check on bottom friction coefficient ! ictu = 0 ! counter for stability criterion breaches at U-pts ictv = 0 ! counter for stability criterion breaches at V-pts zminbfr = 1.e10_wp ! initialise tracker for minimum of bottom friction coefficient zmaxbfr = -1.e10_wp ! initialise tracker for maximum of bottom friction coefficient ! # if defined key_vectopt_loop DO jj = 1, 1 !CDIR NOVERRCHK DO ji = jpi+2, jpij-jpi-1 ! vector opt. (forced unrolling) # else !CDIR NOVERRCHK DO jj = 2, jpjm1 !CDIR NOVERRCHK DO ji = 2, jpim1 # endif ikbu = mbku(ji,jj) ! deepest ocean level at u- and v-points ikbv = mbkv(ji,jj) zfru = 0.5 * fse3u(ji,jj,ikbu) / rdt zfrv = 0.5 * fse3v(ji,jj,ikbv) / rdt IF( ABS( bfrcoef2d(ji,jj) ) > zfru ) THEN IF( ln_ctl ) THEN WRITE(numout,*) 'BFR ', narea, nimpp+ji, njmpp+jj, ikbu WRITE(numout,*) 'BFR ', ABS( bfrcoef2d(ji,jj) ), zfru ENDIF ictu = ictu + 1 ENDIF IF( ABS( bfrcoef2d(ji,jj) ) > zfrv ) THEN IF( ln_ctl ) THEN WRITE(numout,*) 'BFR ', narea, nimpp+ji, njmpp+jj, ikbv WRITE(numout,*) 'BFR ', bfrcoef2d(ji,jj), zfrv ENDIF ictv = ictv + 1 ENDIF zminbfr = MIN( zminbfr, MIN( zfru, ABS( bfrcoef2d(ji,jj) ) ) ) zmaxbfr = MAX( zmaxbfr, MIN( zfrv, ABS( bfrcoef2d(ji,jj) ) ) ) END DO END DO IF( lk_mpp ) THEN CALL mpp_sum( ictu ) CALL mpp_sum( ictv ) CALL mpp_min( zminbfr ) CALL mpp_max( zmaxbfr ) ENDIF IF( .NOT.ln_bfrimp) THEN IF( lwp .AND. ictu + ictv > 0 ) THEN WRITE(numout,*) ' Bottom friction stability check failed at ', ictu, ' U-points ' WRITE(numout,*) ' Bottom friction stability check failed at ', ictv, ' V-points ' WRITE(numout,*) ' Bottom friction coefficient now ranges from: ', zminbfr, ' to ', zmaxbfr WRITE(numout,*) ' Bottom friction coefficient will be reduced where necessary' ENDIF ENDIF ! IF( nn_timing == 1 ) CALL timing_stop('zdf_bfr_init') ! END SUBROUTINE zdf_bfr_init !!====================================================================== END MODULE zdfbfr