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zdfbfr.F90 in trunk/NEMOGCM/NEMO/OPA_SRC/ZDF – NEMO

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source: trunk/NEMOGCM/NEMO/OPA_SRC/ZDF/zdfbfr.F90 @ 3294

Last change on this file since 3294 was 3294, checked in by rblod, 12 years ago
Merge of 3.4beta into the trunk
Property svn:keywords set to `Id`
File size: 13.6 KB

Rev	Line
[3]	1	MODULE zdfbfr
	2	!!======================================================================
	3	!! * MODULE zdfbfr *
	4	!! Ocean physics: Bottom friction
	5	!!======================================================================
[1662]	6	!! History : OPA ! 1997-06 (G. Madec, A.-M. Treguier) Original code
[1601]	7	!! NEMO 1.0 ! 2002-06 (G. Madec) F90: Free form and module
[1708]	8	!! 3.2 ! 2009-09 (A.C.Coward) Correction to include barotropic contribution
[2528]	9	!! 3.3 ! 2010-10 (C. Ethe, G. Madec) reorganisation of initialisation phase
[1601]	10	!!----------------------------------------------------------------------
[3]	11
	12	!!----------------------------------------------------------------------
[1601]	13	!! zdf_bfr : update momentum Kz at the ocean bottom due to the type of bottom friction chosen
	14	!! zdf_bfr_init : read in namelist and control the bottom friction parameters.
[2528]	15	!! zdf_bfr_2d : read in namelist and control the bottom friction parameters.
[3]	16	!!----------------------------------------------------------------------
	17	USE oce ! ocean dynamics and tracers variables
	18	USE dom_oce ! ocean space and time domain variables
	19	USE zdf_oce ! ocean vertical physics variables
	20	USE in_out_manager ! I/O manager
	21	USE lbclnk ! ocean lateral boundary conditions (or mpp link)
[1671]	22	USE lib_mpp ! distributed memory computing
[258]	23	USE prtctl ! Print control
[3294]	24	USE timing ! Timing
[3]	25
	26	IMPLICIT NONE
	27	PRIVATE
	28
[2528]	29	PUBLIC zdf_bfr ! called by step.F90
	30	PUBLIC zdf_bfr_init ! called by opa.F90
[2715]	31
[1708]	32	! !!* Namelist nambfr: bottom friction namelist *
	33	INTEGER :: nn_bfr = 0 ! = 0/1/2/3 type of bottom friction
	34	REAL(wp) :: rn_bfri1 = 4.0e-4_wp ! bottom drag coefficient (linear case)
	35	REAL(wp) :: rn_bfri2 = 1.0e-3_wp ! bottom drag coefficient (non linear case)
	36	REAL(wp) :: rn_bfeb2 = 2.5e-3_wp ! background bottom turbulent kinetic energy [m2/s2]
[2528]	37	REAL(wp) :: rn_bfrien = 30._wp ! local factor to enhance coefficient bfri
[1708]	38	LOGICAL :: ln_bfr2d = .false. ! logical switch for 2D enhancement
[3294]	39	LOGICAL , PUBLIC :: ln_bfrimp = .false. ! logical switch for implicit bottom friction
	40	REAL(wp), ALLOCATABLE, SAVE, DIMENSION(:,:) :: bfrcoef2d ! 2D bottom drag coefficient
[3]	41
	42	!! * Substitutions
[2528]	43	# include "vectopt_loop_substitute.h90"
[3]	44	# include "domzgr_substitute.h90"
	45	!!----------------------------------------------------------------------
[2715]	46	!! NEMO/OPA 4.0 , NEMO Consortium (2011)
[2528]	47	!! $Id$
	48	!! Software governed by the CeCILL licence (NEMOGCM/NEMO_CeCILL.txt)
[3]	49	!!----------------------------------------------------------------------
	50	CONTAINS
	51
[2715]	52	INTEGER FUNCTION zdf_bfr_alloc()
	53	!!----------------------------------------------------------------------
	54	!! * FUNCTION zdf_bfr_alloc *
	55	!!----------------------------------------------------------------------
	56	ALLOCATE( bfrcoef2d(jpi,jpj), STAT=zdf_bfr_alloc )
	57	!
	58	IF( lk_mpp ) CALL mpp_sum ( zdf_bfr_alloc )
	59	IF( zdf_bfr_alloc /= 0 ) CALL ctl_warn('zdf_bfr_alloc: failed to allocate arrays.')
	60	END FUNCTION zdf_bfr_alloc
	61
	62
[3]	63	SUBROUTINE zdf_bfr( kt )
	64	!!----------------------------------------------------------------------
	65	!! * ROUTINE zdf_bfr *
	66	!!
[1708]	67	!! ** Purpose : compute the bottom friction coefficient.
[3]	68	!!
[1662]	69	!! ** Method : Calculate and store part of the momentum trend due
	70	!! to bottom friction following the chosen friction type
	71	!! (free-slip, linear, or quadratic). The component
	72	!! calculated here is multiplied by the bottom velocity in
	73	!! dyn_bfr to provide the trend term.
[1708]	74	!! The coefficients are updated at each time step only
	75	!! in the quadratic case.
[1662]	76	!!
	77	!! ** Action : bfrua , bfrva bottom friction coefficients
[3]	78	!!----------------------------------------------------------------------
	79	INTEGER, INTENT( in ) :: kt ! ocean time-step index
[1601]	80	!!
[2528]	81	INTEGER :: ji, jj ! dummy loop indices
	82	INTEGER :: ikbu, ikbv ! local integers
[1662]	83	REAL(wp) :: zvu, zuv, zecu, zecv ! temporary scalars
[3]	84	!!----------------------------------------------------------------------
[3294]	85	!
	86	IF( nn_timing == 1 ) CALL timing_start('zdf_bfr')
	87	!
[1662]	88	IF( nn_bfr == 2 ) THEN ! quadratic botton friction
[1708]	89	! Calculate and store the quadratic bottom friction coefficient bfrua and bfrva
[1662]	90	! where bfrUa = C_d*SQRT(u_bot^2 + v_bot^2 + e_b) {U=[u,v]}
	91	! from these the trend due to bottom friction: -F_h/e3U can be calculated
	92	! where -F_h/e3U_bot = bfrUa*Ub/e3U_bot {U=[u,v]}
	93	!
[789]	94	# if defined key_vectopt_loop
[1601]	95	DO jj = 1, 1
[3]	96	!CDIR NOVERRCHK
[1601]	97	DO ji = jpi+2, jpij-jpi-1 ! vector opt. (forced unrolling)
[3]	98	# else
	99	!CDIR NOVERRCHK
	100	DO jj = 2, jpjm1
	101	!CDIR NOVERRCHK
	102	DO ji = 2, jpim1
	103	# endif
[2528]	104	ikbu = mbku(ji,jj) ! ocean bottom level at u- and v-points
	105	ikbv = mbkv(ji,jj) ! (deepest ocean u- and v-points)
[1662]	106	!
[2528]	107	zvu = 0.25 * ( vn(ji,jj ,ikbu) + vn(ji+1,jj ,ikbu) &
	108	& + vn(ji,jj-1,ikbu) + vn(ji+1,jj-1,ikbu) )
	109	zuv = 0.25 * ( un(ji,jj ,ikbv) + un(ji-1,jj ,ikbv) &
	110	& + un(ji,jj+1,ikbv) + un(ji-1,jj+1,ikbv) )
[1662]	111	!
[2528]	112	zecu = SQRT( un(ji,jj,ikbu) * un(ji,jj,ikbu) + zvu*zvu + rn_bfeb2 )
	113	zecv = SQRT( vn(ji,jj,ikbv) * vn(ji,jj,ikbv) + zuv*zuv + rn_bfeb2 )
[1662]	114	!
[2528]	115	bfrua(ji,jj) = - 0.5_wp * ( bfrcoef2d(ji,jj) + bfrcoef2d(ji+1,jj ) ) * zecu
	116	bfrva(ji,jj) = - 0.5_wp * ( bfrcoef2d(ji,jj) + bfrcoef2d(ji ,jj+1) ) * zecv
[3]	117	END DO
	118	END DO
[1601]	119	!
[1708]	120	CALL lbc_lnk( bfrua, 'U', 1. ) ; CALL lbc_lnk( bfrva, 'V', 1. ) ! Lateral boundary condition
	121	!
	122	IF(ln_ctl) CALL prt_ctl( tab2d_1=bfrua, clinfo1=' bfr - u: ', mask1=umask, &
	123	& tab2d_2=bfrva, clinfo2= ' v: ', mask2=vmask,ovlap=1 )
[1662]	124	ENDIF
[3294]	125
[1662]	126	!
[3294]	127	IF( nn_timing == 1 ) CALL timing_stop('zdf_bfr')
	128	!
[3]	129	END SUBROUTINE zdf_bfr
	130
	131
	132	SUBROUTINE zdf_bfr_init
	133	!!----------------------------------------------------------------------
	134	!! * ROUTINE zdf_bfr_init *
	135	!!
	136	!! ** Purpose : Initialization of the bottom friction
	137	!!
	138	!! ** Method : Read the nammbf namelist and check their consistency
[1662]	139	!! called at the first timestep (nit000)
[3]	140	!!----------------------------------------------------------------------
[1662]	141	USE iom ! I/O module for ehanced bottom friction file
	142	!!
[2528]	143	INTEGER :: inum ! logical unit for enhanced bottom friction file
	144	INTEGER :: ji, jj ! dummy loop indexes
	145	INTEGER :: ikbu, ikbv ! temporary integers
	146	INTEGER :: ictu, ictv ! - -
	147	REAL(wp) :: zminbfr, zmaxbfr ! temporary scalars
	148	REAL(wp) :: zfru, zfrv ! - -
[1708]	149	!!
[3294]	150	NAMELIST/nambfr/ nn_bfr, rn_bfri1, rn_bfri2, rn_bfeb2, ln_bfr2d, rn_bfrien, ln_bfrimp
[3]	151	!!----------------------------------------------------------------------
[3294]	152	!
	153	IF( nn_timing == 1 ) CALL timing_start('zdf_bfr_init')
	154	!
[1662]	155	REWIND ( numnam ) !* Read Namelist nam_bfr : bottom momentum boundary condition
	156	READ ( numnam, nambfr )
[3]	157
[1662]	158	! !* Parameter control and print
	159	IF(lwp) WRITE(numout,*)
[3]	160	IF(lwp) WRITE(numout,*) 'zdf_bfr : momentum bottom friction'
	161	IF(lwp) WRITE(numout,*) '~~~~~~~'
[1708]	162	IF(lwp) WRITE(numout,*) ' Namelist nam_bfr : set bottom friction parameters'
[3]	163
[2715]	164	! ! allocate zdfbfr arrays
	165	IF( zdf_bfr_alloc() /= 0 ) CALL ctl_stop( 'STOP', 'zdf_bfr_init : unable to allocate arrays' )
	166
[3294]	167	! ! Make sure ln_zdfexp=.false. when use implicit bfr
	168	IF( ln_bfrimp .AND. ln_zdfexp ) THEN
	169	IF(lwp) THEN
	170	WRITE(numout,*)
	171	WRITE(numout,*) 'Implicit bottom friction can only be used when ln_zdfexp=.false.'
	172	WRITE(numout,*) ' but you set: ln_bfrimp=.true. and ln_zdfexp=.true.!!!!'
	173	WRITE(ctmp1,*) ' set either ln_zdfexp = .false or ln_bfrimp = .false.'
	174	CALL ctl_stop( ctmp1 )
	175	END IF
	176	END IF
	177
[1662]	178	SELECT CASE (nn_bfr)
[2715]	179	!
[3]	180	CASE( 0 )
[1708]	181	IF(lwp) WRITE(numout,*) ' free-slip '
[1662]	182	bfrua(:,:) = 0.e0
	183	bfrva(:,:) = 0.e0
	184	!
[3]	185	CASE( 1 )
[1708]	186	IF(lwp) WRITE(numout,*) ' linear botton friction'
	187	IF(lwp) WRITE(numout,*) ' friction coef. rn_bfri1 = ', rn_bfri1
	188	IF( ln_bfr2d ) THEN
	189	IF(lwp) WRITE(numout,*) ' read coef. enhancement distribution from file ln_bfr2d = ', ln_bfr2d
	190	IF(lwp) WRITE(numout,*) ' coef rn_bfri2 enhancement factor rn_bfrien = ',rn_bfrien
[1662]	191	ENDIF
[1601]	192	!
[1662]	193	bfrcoef2d(:,:) = rn_bfri1 ! initialize bfrcoef2d to the namelist variable
[1708]	194	!
	195	IF(ln_bfr2d) THEN
[1662]	196	! bfr_coef is a coefficient in [0,1] giving the mask where to apply the bfr enhancement
	197	CALL iom_open('bfr_coef.nc',inum)
	198	CALL iom_get (inum, jpdom_data, 'bfr_coef',bfrcoef2d,1) ! bfrcoef2d is used as tmp array
	199	CALL iom_close(inum)
[2715]	200	bfrcoef2d(:,:) = rn_bfri1 * ( 1 + rn_bfrien * bfrcoef2d(:,:) )
[1662]	201	ENDIF
	202	bfrua(:,:) = - bfrcoef2d(:,:)
	203	bfrva(:,:) = - bfrcoef2d(:,:)
	204	!
[3]	205	CASE( 2 )
[1708]	206	IF(lwp) WRITE(numout,*) ' quadratic botton friction'
	207	IF(lwp) WRITE(numout,*) ' friction coef. rn_bfri2 = ', rn_bfri2
	208	IF(lwp) WRITE(numout,*) ' background tke rn_bfeb2 = ', rn_bfeb2
	209	IF( ln_bfr2d ) THEN
	210	IF(lwp) WRITE(numout,*) ' read coef. enhancement distribution from file ln_bfr2d = ', ln_bfr2d
	211	IF(lwp) WRITE(numout,*) ' coef rn_bfri2 enhancement factor rn_bfrien = ',rn_bfrien
[1662]	212	ENDIF
	213	bfrcoef2d(:,:) = rn_bfri2 ! initialize bfrcoef2d to the namelist variable
[1708]	214	!
	215	IF(ln_bfr2d) THEN
[1662]	216	! bfr_coef is a coefficient in [0,1] giving the mask where to apply the bfr enhancement
	217	CALL iom_open('bfr_coef.nc',inum)
	218	CALL iom_get (inum, jpdom_data, 'bfr_coef',bfrcoef2d,1) ! bfrcoef2d is used as tmp array
	219	CALL iom_close(inum)
[1708]	220	bfrcoef2d(:,:)= rn_bfri2 * ( 1 + rn_bfrien * bfrcoef2d(:,:) )
[1662]	221	ENDIF
[1601]	222	!
[3]	223	CASE DEFAULT
[1708]	224	IF(lwp) WRITE(ctmp1,*) ' bad flag value for nn_bfr = ', nn_bfr
[474]	225	CALL ctl_stop( ctmp1 )
[1601]	226	!
[3]	227	END SELECT
[3294]	228	IF(lwp) WRITE(numout,*) ' implicit bottom friction switch ln_bfrimp = ', ln_bfrimp
[1601]	229	!
[1662]	230	! Basic stability check on bottom friction coefficient
	231	!
	232	ictu = 0 ! counter for stability criterion breaches at U-pts
	233	ictv = 0 ! counter for stability criterion breaches at V-pts
[1708]	234	zminbfr = 1.e10_wp ! initialise tracker for minimum of bottom friction coefficient
	235	zmaxbfr = -1.e10_wp ! initialise tracker for maximum of bottom friction coefficient
[1662]	236	!
	237	# if defined key_vectopt_loop
	238	DO jj = 1, 1
	239	!CDIR NOVERRCHK
	240	DO ji = jpi+2, jpij-jpi-1 ! vector opt. (forced unrolling)
	241	# else
	242	!CDIR NOVERRCHK
	243	DO jj = 2, jpjm1
	244	!CDIR NOVERRCHK
	245	DO ji = 2, jpim1
	246	# endif
[2528]	247	ikbu = mbku(ji,jj) ! deepest ocean level at u- and v-points
	248	ikbv = mbkv(ji,jj)
	249	zfru = 0.5 * fse3u(ji,jj,ikbu) / rdt
	250	zfrv = 0.5 * fse3v(ji,jj,ikbv) / rdt
[1708]	251	IF( ABS( bfrcoef2d(ji,jj) ) > zfru ) THEN
	252	IF( ln_ctl ) THEN
[2528]	253	WRITE(numout,*) 'BFR ', narea, nimpp+ji, njmpp+jj, ikbu
	254	WRITE(numout,*) 'BFR ', ABS( bfrcoef2d(ji,jj) ), zfru
[1662]	255	ENDIF
	256	ictu = ictu + 1
	257	ENDIF
[1708]	258	IF( ABS( bfrcoef2d(ji,jj) ) > zfrv ) THEN
	259	IF( ln_ctl ) THEN
	260	WRITE(numout,*) 'BFR ', narea, nimpp+ji, njmpp+jj, ikbv
	261	WRITE(numout,*) 'BFR ', bfrcoef2d(ji,jj), zfrv
[1662]	262	ENDIF
	263	ictv = ictv + 1
	264	ENDIF
[1708]	265	zminbfr = MIN( zminbfr, MIN( zfru, ABS( bfrcoef2d(ji,jj) ) ) )
	266	zmaxbfr = MAX( zmaxbfr, MIN( zfrv, ABS( bfrcoef2d(ji,jj) ) ) )
[1662]	267	END DO
	268	END DO
[1708]	269	IF( lk_mpp ) THEN
[1662]	270	CALL mpp_sum( ictu )
	271	CALL mpp_sum( ictv )
[1708]	272	CALL mpp_min( zminbfr )
	273	CALL mpp_max( zmaxbfr )
[1662]	274	ENDIF
[3294]	275	IF( .NOT.ln_bfrimp) THEN
[2528]	276	IF( lwp .AND. ictu + ictv > 0 ) THEN
[1662]	277	WRITE(numout,*) ' Bottom friction stability check failed at ', ictu, ' U-points '
	278	WRITE(numout,*) ' Bottom friction stability check failed at ', ictv, ' V-points '
[1708]	279	WRITE(numout,*) ' Bottom friction coefficient now ranges from: ', zminbfr, ' to ', zmaxbfr
	280	WRITE(numout,*) ' Bottom friction coefficient will be reduced where necessary'
[1662]	281	ENDIF
[3294]	282	ENDIF
[1662]	283	!
[3294]	284	IF( nn_timing == 1 ) CALL timing_stop('zdf_bfr_init')
	285	!
[3]	286	END SUBROUTINE zdf_bfr_init
	287
	288	!!======================================================================
	289	END MODULE zdfbfr

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