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asminc.F90 in trunk/NEMOGCM/NEMO/OPA_SRC/ASM – NEMO

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source: trunk/NEMOGCM/NEMO/OPA_SRC/ASM/asminc.F90 @ 4070

Last change on this file since 4070 was 4070, checked in by djlea, 11 years ago
#1087: Bug fix to freezing temperature used in ASM code.
Property svn:keywords set to `Id`
File size: 48.4 KB

Rev	Line
[2128]	1	MODULE asminc
	2	!!======================================================================
	3	!! * MODULE asminc *
	4	!! Assimilation increment : Apply an increment generated by data
	5	!! assimilation
	6	!!======================================================================
[2392]	7	!! History : ! 2007-03 (M. Martin) Met Office version
	8	!! ! 2007-04 (A. Weaver) calc_date original code
	9	!! ! 2007-04 (A. Weaver) Merge with OPAVAR/NEMOVAR
	10	!! NEMO 3.3 ! 2010-05 (D. Lea) Update to work with NEMO v3.2
	11	!! - ! 2010-05 (D. Lea) add calc_month_len routine based on day_init
[3764]	12	!! 3.4 ! 2012-10 (A. Weaver and K. Mogensen) Fix for direct initialization
[2392]	13	!!----------------------------------------------------------------------
[2128]	14
	15	!!----------------------------------------------------------------------
[3785]	16	!! 'key_asminc' : Switch on the assimilation increment interface
[2128]	17	!!----------------------------------------------------------------------
[3785]	18	!! asm_inc_init : Initialize the increment arrays and IAU weights
	19	!! calc_date : Compute the calendar date YYYYMMDD on a given step
	20	!! tra_asm_inc : Apply the tracer (T and S) increments
	21	!! dyn_asm_inc : Apply the dynamic (u and v) increments
	22	!! ssh_asm_inc : Apply the SSH increment
	23	!! seaice_asm_inc : Apply the seaice increment
[2128]	24	!!----------------------------------------------------------------------
[3294]	25	USE wrk_nemo ! Memory Allocation
[2392]	26	USE par_oce ! Ocean space and time domain variables
	27	USE dom_oce ! Ocean space and time domain
[3785]	28	USE domvvl ! domain: variable volume level
[2392]	29	USE oce ! Dynamics and active tracers defined in memory
[3294]	30	USE ldfdyn_oce ! ocean dynamics: lateral physics
[2392]	31	USE eosbn2 ! Equation of state - in situ and potential density
	32	USE zpshde ! Partial step : Horizontal Derivative
	33	USE iom ! Library to read input files
	34	USE asmpar ! Parameters for the assmilation interface
[2435]	35	USE c1d ! 1D initialization
[2715]	36	USE in_out_manager ! I/O manager
[3764]	37	USE lib_mpp ! MPP library
	38	#if defined key_lim2
	39	USE ice_2 ! LIM2
	40	#endif
	41	USE sbc_oce ! Surface boundary condition variables.
[2128]	42
	43	IMPLICIT NONE
	44	PRIVATE
[2392]	45
	46	PUBLIC asm_inc_init !: Initialize the increment arrays and IAU weights
	47	PUBLIC calc_date !: Compute the calendar date YYYYMMDD on a given step
	48	PUBLIC tra_asm_inc !: Apply the tracer (T and S) increments
	49	PUBLIC dyn_asm_inc !: Apply the dynamic (u and v) increments
	50	PUBLIC ssh_asm_inc !: Apply the SSH increment
[3764]	51	PUBLIC seaice_asm_inc !: Apply the seaice increment
[2128]	52
	53	#if defined key_asminc
[2392]	54	LOGICAL, PUBLIC, PARAMETER :: lk_asminc = .TRUE. !: Logical switch for assimilation increment interface
[2128]	55	#else
[2392]	56	LOGICAL, PUBLIC, PARAMETER :: lk_asminc = .FALSE. !: No assimilation increments
[2128]	57	#endif
	58	LOGICAL, PUBLIC :: ln_bkgwri = .FALSE. !: No output of the background state fields
	59	LOGICAL, PUBLIC :: ln_asmiau = .FALSE. !: No applying forcing with an assimilation increment
	60	LOGICAL, PUBLIC :: ln_asmdin = .FALSE. !: No direct initialization
	61	LOGICAL, PUBLIC :: ln_trainc = .FALSE. !: No tracer (T and S) assimilation increments
	62	LOGICAL, PUBLIC :: ln_dyninc = .FALSE. !: No dynamics (u and v) assimilation increments
	63	LOGICAL, PUBLIC :: ln_sshinc = .FALSE. !: No sea surface height assimilation increment
[3764]	64	LOGICAL, PUBLIC :: ln_seaiceinc = .FALSE. !: No sea ice concentration increment
[2128]	65	LOGICAL, PUBLIC :: ln_salfix = .FALSE. !: Apply minimum salinity check
[3764]	66	LOGICAL, PUBLIC :: ln_temnofreeze = .FALSE. !: Don't allow the temperature to drop below freezing
[3294]	67	INTEGER, PUBLIC :: nn_divdmp = 0 !: Apply divergence damping filter nn_divdmp times
[2128]	68
[2392]	69	REAL(wp), PUBLIC, DIMENSION(:,:,:), ALLOCATABLE :: t_bkg , s_bkg !: Background temperature and salinity
	70	REAL(wp), PUBLIC, DIMENSION(:,:,:), ALLOCATABLE :: u_bkg , v_bkg !: Background u- & v- velocity components
	71	REAL(wp), PUBLIC, DIMENSION(:,:,:), ALLOCATABLE :: t_bkginc, s_bkginc !: Increment to the background T & S
	72	REAL(wp), PUBLIC, DIMENSION(:,:,:), ALLOCATABLE :: u_bkginc, v_bkginc !: Increment to the u- & v-components
	73	REAL(wp), PUBLIC, DIMENSION(:) , ALLOCATABLE :: wgtiau !: IAU weights for each time step
[2128]	74	#if defined key_asminc
[2392]	75	REAL(wp), PUBLIC, DIMENSION(:,:), ALLOCATABLE :: ssh_iau !: IAU-weighted sea surface height increment
[2128]	76	#endif
[2392]	77	! !!! time steps relative to the cycle interval [0,nitend-nit000-1]
	78	INTEGER , PUBLIC :: nitbkg !: Time step of the background state used in the Jb term
	79	INTEGER , PUBLIC :: nitdin !: Time step of the background state for direct initialization
	80	INTEGER , PUBLIC :: nitiaustr !: Time step of the start of the IAU interval
	81	INTEGER , PUBLIC :: nitiaufin !: Time step of the end of the IAU interval
	82	!
	83	INTEGER , PUBLIC :: niaufn !: Type of IAU weighing function: = 0 Constant weighting
	84	! !: = 1 Linear hat-like, centred in middle of IAU interval
	85	REAL(wp), PUBLIC :: salfixmin !: Ensure that the salinity is larger than this value if (ln_salfix)
[2128]	86
[2392]	87	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: ssh_bkg, ssh_bkginc ! Background sea surface height and its increment
[3764]	88	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: seaice_bkginc ! Increment to the background sea ice conc
[2128]	89
[3294]	90	!! * Substitutions
	91	# include "domzgr_substitute.h90"
	92	# include "ldfdyn_substitute.h90"
	93	# include "vectopt_loop_substitute.h90"
[2287]	94	!!----------------------------------------------------------------------
	95	!! NEMO/OPA 3.3 , NEMO Consortium (2010)
	96	!! $Id$
[2392]	97	!! Software governed by the CeCILL licence (NEMOGCM/NEMO_CeCILL.txt)
[2287]	98	!!----------------------------------------------------------------------
[2128]	99	CONTAINS
	100
	101	SUBROUTINE asm_inc_init
	102	!!----------------------------------------------------------------------
	103	!! * ROUTINE asm_inc_init *
	104	!!
	105	!! ** Purpose : Initialize the assimilation increment and IAU weights.
	106	!!
	107	!! ** Method : Initialize the assimilation increment and IAU weights.
	108	!!
	109	!! ** Action :
	110	!!----------------------------------------------------------------------
[3785]	111	INTEGER :: ji, jj, jk
[2128]	112	INTEGER :: jt
	113	INTEGER :: imid
	114	INTEGER :: inum
	115	INTEGER :: iiauper ! Number of time steps in the IAU period
	116	INTEGER :: icycper ! Number of time steps in the cycle
	117	INTEGER :: iitend_date ! Date YYYYMMDD of final time step
	118	INTEGER :: iitbkg_date ! Date YYYYMMDD of background time step for Jb term
	119	INTEGER :: iitdin_date ! Date YYYYMMDD of background time step for DI
	120	INTEGER :: iitiaustr_date ! Date YYYYMMDD of IAU interval start time step
	121	INTEGER :: iitiaufin_date ! Date YYYYMMDD of IAU interval final time step
	122
	123	REAL(wp) :: znorm ! Normalization factor for IAU weights
	124	REAL(wp) :: ztotwgt ! Value of time-integrated IAU weights
	125	! (should be equal to one)
	126	REAL(wp) :: z_inc_dateb ! Start date of interval on which increment is valid
	127	REAL(wp) :: z_inc_datef ! End date of interval on which increment is valid
	128	REAL(wp) :: zdate_bkg ! Date in background state file for DI
	129	REAL(wp) :: zdate_inc ! Time axis in increments file
[3294]	130
	131	REAL(wp), POINTER, DIMENSION(:,:) :: hdiv
[2392]	132	!!
[3764]	133	NAMELIST/nam_asminc/ ln_bkgwri, &
[2392]	134	& ln_trainc, ln_dyninc, ln_sshinc, &
	135	& ln_asmdin, ln_asmiau, &
	136	& nitbkg, nitdin, nitiaustr, nitiaufin, niaufn, &
[3764]	137	& ln_salfix, salfixmin, &
[3294]	138	& nn_divdmp
[2392]	139	!!----------------------------------------------------------------------
[2128]	140
	141	!-----------------------------------------------------------------------
	142	! Read Namelist nam_asminc : assimilation increment interface
	143	!-----------------------------------------------------------------------
	144
	145	! Set default values
	146	ln_bkgwri = .FALSE.
	147	ln_trainc = .FALSE.
	148	ln_dyninc = .FALSE.
	149	ln_sshinc = .FALSE.
[3764]	150	ln_seaiceinc = .FALSE.
[2128]	151	ln_asmdin = .FALSE.
	152	ln_asmiau = .TRUE.
	153	ln_salfix = .FALSE.
[3764]	154	ln_temnofreeze = .FALSE.
[2128]	155	salfixmin = -9999
	156	nitbkg = 0
	157	nitdin = 0
	158	nitiaustr = 1
	159	nitiaufin = 150 ! = 10 days with ORCA2
	160	niaufn = 0
	161
	162	REWIND ( numnam )
	163	READ ( numnam, nam_asminc )
	164
	165	! Control print
	166	IF(lwp) THEN
	167	WRITE(numout,*)
	168	WRITE(numout,*) 'asm_inc_init : Assimilation increment initialization :'
	169	WRITE(numout,*) '~~~~~~~~~~~~'
[2392]	170	WRITE(numout,*) ' Namelist namasm : set assimilation increment parameters'
	171	WRITE(numout,*) ' Logical switch for writing out background state ln_bkgwri = ', ln_bkgwri
	172	WRITE(numout,*) ' Logical switch for applying tracer increments ln_trainc = ', ln_trainc
	173	WRITE(numout,*) ' Logical switch for applying velocity increments ln_dyninc = ', ln_dyninc
	174	WRITE(numout,*) ' Logical switch for applying SSH increments ln_sshinc = ', ln_sshinc
	175	WRITE(numout,*) ' Logical switch for Direct Initialization (DI) ln_asmdin = ', ln_asmdin
[3764]	176	WRITE(numout,*) ' Logical switch for applying sea ice increments ln_seaiceinc = ', ln_seaiceinc
[2392]	177	WRITE(numout,*) ' Logical switch for Incremental Analysis Updating (IAU) ln_asmiau = ', ln_asmiau
	178	WRITE(numout,*) ' Timestep of background in [0,nitend-nit000-1] nitbkg = ', nitbkg
	179	WRITE(numout,*) ' Timestep of background for DI in [0,nitend-nit000-1] nitdin = ', nitdin
	180	WRITE(numout,*) ' Timestep of start of IAU interval in [0,nitend-nit000-1] nitiaustr = ', nitiaustr
	181	WRITE(numout,*) ' Timestep of end of IAU interval in [0,nitend-nit000-1] nitiaufin = ', nitiaufin
	182	WRITE(numout,*) ' Type of IAU weighting function niaufn = ', niaufn
	183	WRITE(numout,*) ' Logical switch for ensuring that the sa > salfixmin ln_salfix = ', ln_salfix
	184	WRITE(numout,*) ' Minimum salinity after applying the increments salfixmin = ', salfixmin
[2128]	185	ENDIF
	186
	187	nitbkg_r = nitbkg + nit000 - 1 ! Background time referenced to nit000
	188	nitdin_r = nitdin + nit000 - 1 ! Background time for DI referenced to nit000
	189	nitiaustr_r = nitiaustr + nit000 - 1 ! Start of IAU interval referenced to nit000
	190	nitiaufin_r = nitiaufin + nit000 - 1 ! End of IAU interval referenced to nit000
	191
	192	iiauper = nitiaufin_r - nitiaustr_r + 1 ! IAU interval length
	193	icycper = nitend - nit000 + 1 ! Cycle interval length
	194
	195	! Date of final time step
	196	CALL calc_date( nit000, nitend, ndate0, iitend_date )
	197
	198	! Background time for Jb referenced to ndate0
	199	CALL calc_date( nit000, nitbkg_r, ndate0, iitbkg_date )
	200
	201	! Background time for DI referenced to ndate0
	202	CALL calc_date( nit000, nitdin_r, ndate0, iitdin_date )
	203
	204	! IAU start time referenced to ndate0
	205	CALL calc_date( nit000, nitiaustr_r, ndate0, iitiaustr_date )
	206
	207	! IAU end time referenced to ndate0
	208	CALL calc_date( nit000, nitiaufin_r, ndate0, iitiaufin_date )
	209
	210	IF(lwp) THEN
	211	WRITE(numout,*)
	212	WRITE(numout,*) ' Time steps referenced to current cycle:'
	213	WRITE(numout,*) ' iitrst = ', nit000 - 1
	214	WRITE(numout,*) ' nit000 = ', nit000
	215	WRITE(numout,*) ' nitend = ', nitend
	216	WRITE(numout,*) ' nitbkg_r = ', nitbkg_r
	217	WRITE(numout,*) ' nitdin_r = ', nitdin_r
	218	WRITE(numout,*) ' nitiaustr_r = ', nitiaustr_r
	219	WRITE(numout,*) ' nitiaufin_r = ', nitiaufin_r
	220	WRITE(numout,*)
	221	WRITE(numout,*) ' Dates referenced to current cycle:'
	222	WRITE(numout,*) ' ndastp = ', ndastp
	223	WRITE(numout,*) ' ndate0 = ', ndate0
	224	WRITE(numout,*) ' iitend_date = ', iitend_date
	225	WRITE(numout,*) ' iitbkg_date = ', iitbkg_date
	226	WRITE(numout,*) ' iitdin_date = ', iitdin_date
	227	WRITE(numout,*) ' iitiaustr_date = ', iitiaustr_date
	228	WRITE(numout,*) ' iitiaufin_date = ', iitiaufin_date
	229	ENDIF
	230
	231	IF ( nacc /= 0 ) &
	232	& CALL ctl_stop( ' nacc /= 0 and key_asminc :', &
	233	& ' Assimilation increments have only been implemented', &
	234	& ' for synchronous time stepping' )
	235
	236	IF ( ( ln_asmdin ).AND.( ln_asmiau ) ) &
	237	& CALL ctl_stop( ' ln_asmdin and ln_asmiau :', &
	238	& ' Choose Direct Initialization OR Incremental Analysis Updating')
	239
	240	IF ( ( ( .NOT. ln_asmdin ).AND.( .NOT. ln_asmiau ) ) &
[3764]	241	.AND.( ( ln_trainc ).OR.( ln_dyninc ).OR.( ln_sshinc ) .OR. ( ln_seaiceinc) )) &
	242	& CALL ctl_stop( ' One or more of ln_trainc, ln_dyninc, ln_sshinc and ln_seaiceinc is set to .true.', &
[2128]	243	& ' but ln_asmdin and ln_asmiau are both set to .false. :', &
	244	& ' Inconsistent options')
	245
	246	IF ( ( ln_bkgwri ).AND.( ( ln_asmdin ).OR.( ln_asmiau ) ) ) &
	247	& CALL ctl_stop( ' ln_bkgwri and either ln_asmdin or ln_asmiau are set to .true.:', &
	248	& ' The background state must be written before applying the increments')
	249
	250	IF ( ( niaufn /= 0 ).AND.( niaufn /= 1 ) ) &
	251	& CALL ctl_stop( ' niaufn /= 0 or niaufn /=1 :', &
	252	& ' Type IAU weighting function is invalid')
	253
[3764]	254	IF ( ( .NOT. ln_trainc ).AND.( .NOT. ln_dyninc ).AND.( .NOT. ln_sshinc ).AND.( .NOT. ln_seaiceinc ) &
[2128]	255	& ) &
[3764]	256	& CALL ctl_warn( ' ln_trainc, ln_dyninc, ln_sshinc and ln_seaiceinc are set to .false. :', &
[2128]	257	& ' The assimilation increments are not applied')
	258
	259	IF ( ( ln_asmiau ).AND.( nitiaustr == nitiaufin ) ) &
	260	& CALL ctl_stop( ' nitiaustr = nitiaufin :', &
	261	& ' IAU interval is of zero length')
	262
	263	IF ( ( ln_asmiau ).AND.( ( nitiaustr_r < nit000 ).OR.( nitiaufin_r > nitend ) ) ) &
	264	& CALL ctl_stop( ' nitiaustr or nitiaufin :', &
	265	& ' IAU starting or final time step is outside the cycle interval', &
	266	& ' Valid range nit000 to nitend')
	267
	268	IF ( ( nitbkg_r < nit000 - 1 ).OR.( nitbkg_r > nitend ) ) &
	269	& CALL ctl_stop( ' nitbkg :', &
	270	& ' Background time step is outside the cycle interval')
	271
	272	IF ( ( nitdin_r < nit000 - 1 ).OR.( nitdin_r > nitend ) ) &
	273	& CALL ctl_stop( ' nitdin :', &
	274	& ' Background time step for Direct Initialization is outside', &
	275	& ' the cycle interval')
	276
	277	IF ( nstop > 0 ) RETURN ! if there are any errors then go no further
	278
	279	!--------------------------------------------------------------------
	280	! Initialize the Incremental Analysis Updating weighting function
	281	!--------------------------------------------------------------------
	282
	283	IF ( ln_asmiau ) THEN
	284
	285	ALLOCATE( wgtiau( icycper ) )
	286
	287	wgtiau(:) = 0.0
	288
	289	IF ( niaufn == 0 ) THEN
	290
	291	!---------------------------------------------------------
	292	! Constant IAU forcing
	293	!---------------------------------------------------------
	294
	295	DO jt = 1, iiauper
	296	wgtiau(jt+nitiaustr-1) = 1.0 / REAL( iiauper )
	297	END DO
	298
	299	ELSEIF ( niaufn == 1 ) THEN
	300
	301	!---------------------------------------------------------
	302	! Linear hat-like, centred in middle of IAU interval
	303	!---------------------------------------------------------
	304
	305	! Compute the normalization factor
	306	znorm = 0.0
	307	IF ( MOD( iiauper, 2 ) == 0 ) THEN ! Even number of time steps in IAU interval
	308	imid = iiauper / 2
	309	DO jt = 1, imid
	310	znorm = znorm + REAL( jt )
	311	END DO
	312	znorm = 2.0 * znorm
	313	ELSE ! Odd number of time steps in IAU interval
	314	imid = ( iiauper + 1 ) / 2
	315	DO jt = 1, imid - 1
	316	znorm = znorm + REAL( jt )
	317	END DO
	318	znorm = 2.0 * znorm + REAL( imid )
	319	ENDIF
	320	znorm = 1.0 / znorm
	321
	322	DO jt = 1, imid - 1
	323	wgtiau(jt+nitiaustr-1) = REAL( jt ) * znorm
	324	END DO
	325	DO jt = imid, iiauper
	326	wgtiau(jt+nitiaustr-1) = REAL( iiauper - jt + 1 ) * znorm
	327	END DO
	328
	329	ENDIF
	330
	331	! Test that the integral of the weights over the weighting interval equals 1
	332	IF(lwp) THEN
	333	WRITE(numout,*)
	334	WRITE(numout,*) 'asm_inc_init : IAU weights'
	335	WRITE(numout,*) '~~~~~~~~~~~~'
	336	WRITE(numout,*) ' time step IAU weight'
	337	WRITE(numout,*) ' ========= ====================='
	338	ztotwgt = 0.0
	339	DO jt = 1, icycper
	340	ztotwgt = ztotwgt + wgtiau(jt)
	341	WRITE(numout,*) ' ', jt, ' ', wgtiau(jt)
	342	END DO
	343	WRITE(numout,*) ' ==================================='
	344	WRITE(numout,*) ' Time-integrated weight = ', ztotwgt
	345	WRITE(numout,*) ' ==================================='
	346	ENDIF
	347
	348	ENDIF
	349
	350	!--------------------------------------------------------------------
	351	! Allocate and initialize the increment arrays
	352	!--------------------------------------------------------------------
	353
	354	ALLOCATE( t_bkginc(jpi,jpj,jpk) )
	355	ALLOCATE( s_bkginc(jpi,jpj,jpk) )
	356	ALLOCATE( u_bkginc(jpi,jpj,jpk) )
	357	ALLOCATE( v_bkginc(jpi,jpj,jpk) )
	358	ALLOCATE( ssh_bkginc(jpi,jpj) )
[3764]	359	ALLOCATE( seaice_bkginc(jpi,jpj))
[2128]	360	#if defined key_asminc
	361	ALLOCATE( ssh_iau(jpi,jpj) )
	362	#endif
	363	t_bkginc(:,:,:) = 0.0
	364	s_bkginc(:,:,:) = 0.0
	365	u_bkginc(:,:,:) = 0.0
	366	v_bkginc(:,:,:) = 0.0
	367	ssh_bkginc(:,:) = 0.0
[3764]	368	seaice_bkginc(:,:) = 0.0
[2128]	369	#if defined key_asminc
	370	ssh_iau(:,:) = 0.0
	371	#endif
[3764]	372	IF ( ( ln_trainc ).OR.( ln_dyninc ).OR.( ln_sshinc ).OR.( ln_seaiceinc ) ) THEN
[2128]	373
	374	!--------------------------------------------------------------------
	375	! Read the increments from file
	376	!--------------------------------------------------------------------
	377
	378	CALL iom_open( c_asminc, inum )
	379
	380	CALL iom_get( inum, 'time', zdate_inc )
	381
	382	CALL iom_get( inum, 'z_inc_dateb', z_inc_dateb )
	383	CALL iom_get( inum, 'z_inc_datef', z_inc_datef )
	384	z_inc_dateb = zdate_inc
	385	z_inc_datef = zdate_inc
	386
	387	IF(lwp) THEN
	388	WRITE(numout,*)
	389	WRITE(numout,*) 'asm_inc_init : Assimilation increments valid ', &
	390	& ' between dates ', NINT( z_inc_dateb ),' and ', &
	391	& NINT( z_inc_datef )
	392	WRITE(numout,*) '~~~~~~~~~~~~'
	393	ENDIF
	394
	395	IF ( ( NINT( z_inc_dateb ) < ndastp ) &
	396	& .OR.( NINT( z_inc_datef ) > iitend_date ) ) &
	397	& CALL ctl_warn( ' Validity time of assimilation increments is ', &
	398	& ' outside the assimilation interval' )
	399
	400	IF ( ( ln_asmdin ).AND.( NINT( zdate_inc ) /= iitdin_date ) ) &
	401	& CALL ctl_warn( ' Validity time of assimilation increments does ', &
	402	& ' not agree with Direct Initialization time' )
	403
	404	IF ( ln_trainc ) THEN
	405	CALL iom_get( inum, jpdom_autoglo, 'bckint', t_bkginc, 1 )
	406	CALL iom_get( inum, jpdom_autoglo, 'bckins', s_bkginc, 1 )
	407	! Apply the masks
	408	t_bkginc(:,:,:) = t_bkginc(:,:,:) * tmask(:,:,:)
	409	s_bkginc(:,:,:) = s_bkginc(:,:,:) * tmask(:,:,:)
	410	! Set missing increments to 0.0 rather than 1e+20
	411	! to allow for differences in masks
	412	WHERE( ABS( t_bkginc(:,:,:) ) > 1.0e+10 ) t_bkginc(:,:,:) = 0.0
	413	WHERE( ABS( s_bkginc(:,:,:) ) > 1.0e+10 ) s_bkginc(:,:,:) = 0.0
	414	ENDIF
	415
	416	IF ( ln_dyninc ) THEN
	417	CALL iom_get( inum, jpdom_autoglo, 'bckinu', u_bkginc, 1 )
	418	CALL iom_get( inum, jpdom_autoglo, 'bckinv', v_bkginc, 1 )
	419	! Apply the masks
	420	u_bkginc(:,:,:) = u_bkginc(:,:,:) * umask(:,:,:)
	421	v_bkginc(:,:,:) = v_bkginc(:,:,:) * vmask(:,:,:)
	422	! Set missing increments to 0.0 rather than 1e+20
	423	! to allow for differences in masks
	424	WHERE( ABS( u_bkginc(:,:,:) ) > 1.0e+10 ) u_bkginc(:,:,:) = 0.0
	425	WHERE( ABS( v_bkginc(:,:,:) ) > 1.0e+10 ) v_bkginc(:,:,:) = 0.0
	426	ENDIF
	427
	428	IF ( ln_sshinc ) THEN
	429	CALL iom_get( inum, jpdom_autoglo, 'bckineta', ssh_bkginc, 1 )
	430	! Apply the masks
	431	ssh_bkginc(:,:) = ssh_bkginc(:,:) * tmask(:,:,1)
	432	! Set missing increments to 0.0 rather than 1e+20
	433	! to allow for differences in masks
	434	WHERE( ABS( ssh_bkginc(:,:) ) > 1.0e+10 ) ssh_bkginc(:,:) = 0.0
	435	ENDIF
	436
[3764]	437	IF ( ln_seaiceinc ) THEN
	438	CALL iom_get( inum, jpdom_autoglo, 'bckinseaice', seaice_bkginc, 1 )
	439	! Apply the masks
	440	seaice_bkginc(:,:) = seaice_bkginc(:,:) * tmask(:,:,1)
	441	! Set missing increments to 0.0 rather than 1e+20
	442	! to allow for differences in masks
	443	WHERE( ABS( seaice_bkginc(:,:) ) > 1.0e+10 ) seaice_bkginc(:,:) = 0.0
	444	ENDIF
	445
[2128]	446	CALL iom_close( inum )
	447
	448	ENDIF
	449
	450	!-----------------------------------------------------------------------
[3294]	451	! Apply divergence damping filter
	452	!-----------------------------------------------------------------------
	453
	454	IF ( ln_dyninc .AND. nn_divdmp > 0 ) THEN
	455
[3764]	456	CALL wrk_alloc(jpi,jpj,hdiv)
[3294]	457
[3764]	458	DO jt = 1, nn_divdmp
[3294]	459
[3764]	460	DO jk = 1, jpkm1
[3294]	461
[3764]	462	hdiv(:,:) = 0._wp
[3294]	463
[3764]	464	DO jj = 2, jpjm1
	465	DO ji = fs_2, fs_jpim1 ! vector opt.
	466	hdiv(ji,jj) = &
	467	( e2u(ji ,jj ) * fse3u(ji ,jj ,jk) * u_bkginc(ji ,jj ,jk) &
	468	- e2u(ji-1,jj ) * fse3u(ji-1,jj ,jk) * u_bkginc(ji-1,jj ,jk) &
	469	+ e1v(ji ,jj ) * fse3v(ji ,jj ,jk) * v_bkginc(ji ,jj ,jk) &
	470	- e1v(ji ,jj-1) * fse3v(ji ,jj-1,jk) * v_bkginc(ji ,jj-1,jk) ) &
	471	/ ( e1t(ji,jj) * e2t(ji,jj) * fse3t(ji,jj,jk) )
	472	END DO
[3294]	473	END DO
	474
[3764]	475	CALL lbc_lnk( hdiv, 'T', 1. ) ! lateral boundary cond. (no sign change)
[3294]	476
[3764]	477	DO jj = 2, jpjm1
	478	DO ji = fs_2, fs_jpim1 ! vector opt.
	479	u_bkginc(ji,jj,jk) = u_bkginc(ji,jj,jk) + 0.2_wp * ( e1t(ji+1,jj)e2t(ji+1,jj) hdiv(ji+1,jj) &
	480	- e1t(ji ,jj)e2t(ji ,jj) hdiv(ji ,jj) ) &
	481	/ e1u(ji,jj) * umask(ji,jj,jk)
	482	v_bkginc(ji,jj,jk) = v_bkginc(ji,jj,jk) + 0.2_wp * ( e1t(ji,jj+1)e2t(ji,jj+1) hdiv(ji,jj+1) &
	483	- e1t(ji,jj )e2t(ji,jj ) hdiv(ji,jj ) ) &
	484	/ e2v(ji,jj) * vmask(ji,jj,jk)
	485	END DO
[3294]	486	END DO
[3764]	487
[3294]	488	END DO
	489
[3764]	490	END DO
[3294]	491
[3764]	492	CALL wrk_dealloc(jpi,jpj,hdiv)
[3294]	493
	494	ENDIF
	495
	496
	497
	498	!-----------------------------------------------------------------------
[2128]	499	! Allocate and initialize the background state arrays
	500	!-----------------------------------------------------------------------
	501
	502	IF ( ln_asmdin ) THEN
	503
	504	ALLOCATE( t_bkg(jpi,jpj,jpk) )
	505	ALLOCATE( s_bkg(jpi,jpj,jpk) )
	506	ALLOCATE( u_bkg(jpi,jpj,jpk) )
	507	ALLOCATE( v_bkg(jpi,jpj,jpk) )
	508	ALLOCATE( ssh_bkg(jpi,jpj) )
	509
	510	t_bkg(:,:,:) = 0.0
	511	s_bkg(:,:,:) = 0.0
	512	u_bkg(:,:,:) = 0.0
	513	v_bkg(:,:,:) = 0.0
	514	ssh_bkg(:,:) = 0.0
	515
	516	!--------------------------------------------------------------------
	517	! Read from file the background state at analysis time
	518	!--------------------------------------------------------------------
	519
	520	CALL iom_open( c_asmdin, inum )
	521
[3764]	522	CALL iom_get( inum, 'rdastp', zdate_bkg )
[2128]	523
	524	IF(lwp) THEN
	525	WRITE(numout,*)
	526	WRITE(numout,*) 'asm_inc_init : Assimilation background state valid at : ', &
	527	& NINT( zdate_bkg )
	528	WRITE(numout,*) '~~~~~~~~~~~~'
	529	ENDIF
	530
	531	IF ( NINT( zdate_bkg ) /= iitdin_date ) &
	532	& CALL ctl_warn( ' Validity time of assimilation background state does', &
	533	& ' not agree with Direct Initialization time' )
	534
	535	IF ( ln_trainc ) THEN
	536	CALL iom_get( inum, jpdom_autoglo, 'tn', t_bkg )
	537	CALL iom_get( inum, jpdom_autoglo, 'sn', s_bkg )
	538	t_bkg(:,:,:) = t_bkg(:,:,:) * tmask(:,:,:)
	539	s_bkg(:,:,:) = s_bkg(:,:,:) * tmask(:,:,:)
	540	ENDIF
	541
	542	IF ( ln_dyninc ) THEN
	543	CALL iom_get( inum, jpdom_autoglo, 'un', u_bkg )
	544	CALL iom_get( inum, jpdom_autoglo, 'vn', v_bkg )
	545	u_bkg(:,:,:) = u_bkg(:,:,:) * umask(:,:,:)
	546	v_bkg(:,:,:) = v_bkg(:,:,:) * vmask(:,:,:)
	547	ENDIF
	548
	549	IF ( ln_sshinc ) THEN
	550	CALL iom_get( inum, jpdom_autoglo, 'sshn', ssh_bkg )
	551	ssh_bkg(:,:) = ssh_bkg(:,:) * tmask(:,:,1)
	552	ENDIF
	553
	554	CALL iom_close( inum )
	555
	556	ENDIF
[2392]	557	!
[2128]	558	END SUBROUTINE asm_inc_init
	559
[2392]	560
[2128]	561	SUBROUTINE calc_date( kit000, kt, kdate0, kdate )
	562	!!----------------------------------------------------------------------
	563	!! * ROUTINE calc_date *
	564	!!
	565	!! ** Purpose : Compute the calendar date YYYYMMDD at a given time step.
	566	!!
	567	!! ** Method : Compute the calendar date YYYYMMDD at a given time step.
	568	!!
	569	!! ** Action :
	570	!!----------------------------------------------------------------------
	571	INTEGER, INTENT(IN) :: kit000 ! Initial time step
	572	INTEGER, INTENT(IN) :: kt ! Current time step referenced to kit000
	573	INTEGER, INTENT(IN) :: kdate0 ! Initial date
	574	INTEGER, INTENT(OUT) :: kdate ! Current date reference to kdate0
[2392]	575	!
[2128]	576	INTEGER :: iyea0 ! Initial year
	577	INTEGER :: imon0 ! Initial month
	578	INTEGER :: iday0 ! Initial day
	579	INTEGER :: iyea ! Current year
	580	INTEGER :: imon ! Current month
	581	INTEGER :: iday ! Current day
	582	INTEGER :: idaystp ! Number of days between initial and current date
	583	INTEGER :: idaycnt ! Day counter
	584
	585	INTEGER, DIMENSION(12) :: imonth_len !: length in days of the months of the current year
	586
	587	!-----------------------------------------------------------------------
	588	! Compute the calendar date YYYYMMDD
	589	!-----------------------------------------------------------------------
	590
	591	! Initial date
	592	iyea0 = kdate0 / 10000
	593	imon0 = ( kdate0 - ( iyea0 * 10000 ) ) / 100
	594	iday0 = kdate0 - ( iyea0 * 10000 ) - ( imon0 * 100 )
	595
	596	! Check that kt >= kit000 - 1
	597	IF ( kt < kit000 - 1 ) CALL ctl_stop( ' kt must be >= kit000 - 1')
	598
	599	! If kt = kit000 - 1 then set the date to the restart date
	600	IF ( kt == kit000 - 1 ) THEN
	601
	602	kdate = ndastp
	603	RETURN
	604
	605	ENDIF
	606
	607	! Compute the number of days from the initial date
	608	idaystp = INT( REAL( kt - kit000 ) * rdt / 86400. )
	609
	610	iday = iday0
	611	imon = imon0
	612	iyea = iyea0
	613	idaycnt = 0
	614
	615	CALL calc_month_len( iyea, imonth_len )
	616
	617	DO WHILE ( idaycnt < idaystp )
	618	iday = iday + 1
	619	IF ( iday > imonth_len(imon) ) THEN
	620	iday = 1
	621	imon = imon + 1
	622	ENDIF
	623	IF ( imon > 12 ) THEN
	624	imon = 1
	625	iyea = iyea + 1
	626	CALL calc_month_len( iyea, imonth_len ) ! update month lengths
	627	ENDIF
	628	idaycnt = idaycnt + 1
	629	END DO
[2392]	630	!
[2128]	631	kdate = iyea * 10000 + imon * 100 + iday
[2392]	632	!
[2128]	633	END SUBROUTINE
	634
[2392]	635
[2128]	636	SUBROUTINE calc_month_len( iyear, imonth_len )
	637	!!----------------------------------------------------------------------
	638	!! * ROUTINE calc_month_len *
	639	!!
	640	!! ** Purpose : Compute the number of days in a months given a year.
	641	!!
	642	!! ** Method :
	643	!!----------------------------------------------------------------------
	644	INTEGER, DIMENSION(12) :: imonth_len !: length in days of the months of the current year
	645	INTEGER :: iyear !: year
[2392]	646	!!----------------------------------------------------------------------
	647	!
[2128]	648	! length of the month of the current year (from nleapy, read in namelist)
	649	IF ( nleapy < 2 ) THEN
	650	imonth_len(:) = (/ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 /)
	651	IF ( nleapy == 1 ) THEN ! we are using calendar with leap years
	652	IF ( MOD(iyear, 4) == 0 .AND. ( MOD(iyear, 400) == 0 .OR. MOD(iyear, 100) /= 0 ) ) THEN
	653	imonth_len(2) = 29
	654	ENDIF
	655	ENDIF
	656	ELSE
	657	imonth_len(:) = nleapy ! all months with nleapy days per year
	658	ENDIF
[2392]	659	!
[2128]	660	END SUBROUTINE
	661
[2392]	662
[2128]	663	SUBROUTINE tra_asm_inc( kt )
	664	!!----------------------------------------------------------------------
	665	!! * ROUTINE tra_asm_inc *
	666	!!
	667	!! ** Purpose : Apply the tracer (T and S) assimilation increments
	668	!!
	669	!! ** Method : Direct initialization or Incremental Analysis Updating
	670	!!
	671	!! ** Action :
	672	!!----------------------------------------------------------------------
	673	INTEGER, INTENT(IN) :: kt ! Current time step
[2392]	674	!
[2128]	675	INTEGER :: ji,jj,jk
	676	INTEGER :: it
	677	REAL(wp) :: zincwgt ! IAU weight for current time step
[3764]	678	REAL (wp), DIMENSION(jpi,jpj,jpk) :: fzptnz ! 3d freezing point values
[2392]	679	!!----------------------------------------------------------------------
[2128]	680
[3764]	681	! freezing point calculation taken from oc_fz_pt (but calculated for all depths)
	682	! used to prevent the applied increments taking the temperature below the local freezing point
	683
[4070]	684	DO jk=1, jpkm1
	685	fzptnz (:,:,jk) = tfreez( tsn(:,:,jk,jp_sal), fsdept(:,:,jk) )
	686	ENDDO
[3764]	687
[2128]	688	IF ( ln_asmiau ) THEN
	689
	690	!--------------------------------------------------------------------
	691	! Incremental Analysis Updating
	692	!--------------------------------------------------------------------
	693
	694	IF ( ( kt >= nitiaustr_r ).AND.( kt <= nitiaufin_r ) ) THEN
	695
	696	it = kt - nit000 + 1
	697	zincwgt = wgtiau(it) / rdt ! IAU weight for the current time step
	698
	699	IF(lwp) THEN
	700	WRITE(numout,*)
	701	WRITE(numout,*) 'tra_asm_inc : Tracer IAU at time step = ', &
	702	& kt,' with IAU weight = ', wgtiau(it)
	703	WRITE(numout,*) '~~~~~~~~~~~~'
	704	ENDIF
	705
	706	! Update the tracer tendencies
	707	DO jk = 1, jpkm1
[3764]	708	IF (ln_temnofreeze) THEN
	709	! Do not apply negative increments if the temperature will fall below freezing
	710	WHERE(t_bkginc(:,:,jk) > 0.0_wp .OR. &
	711	& tsn(:,:,jk,jp_tem) + tsa(:,:,jk,jp_tem) + t_bkginc(:,:,jk) * wgtiau(it) > fzptnz(:,:,jk) )
	712	tsa(:,:,jk,jp_tem) = tsa(:,:,jk,jp_tem) + t_bkginc(:,:,jk) * zincwgt
	713	END WHERE
	714	ELSE
	715	tsa(:,:,jk,jp_tem) = tsa(:,:,jk,jp_tem) + t_bkginc(:,:,jk) * zincwgt
	716	ENDIF
	717	IF (ln_salfix) THEN
	718	! Do not apply negative increments if the salinity will fall below a specified
	719	! minimum value salfixmin
	720	WHERE(s_bkginc(:,:,jk) > 0.0_wp .OR. &
	721	& tsn(:,:,jk,jp_sal) + tsa(:,:,jk,jp_sal) + s_bkginc(:,:,jk) * wgtiau(it) > salfixmin )
	722	tsa(:,:,jk,jp_sal) = tsa(:,:,jk,jp_sal) + s_bkginc(:,:,jk) * zincwgt
	723	END WHERE
	724	ELSE
	725	tsa(:,:,jk,jp_sal) = tsa(:,:,jk,jp_sal) + s_bkginc(:,:,jk) * zincwgt
	726	ENDIF
[2128]	727	END DO
	728
	729	ENDIF
	730
	731	IF ( kt == nitiaufin_r + 1 ) THEN ! For bias crcn to work
	732	DEALLOCATE( t_bkginc )
	733	DEALLOCATE( s_bkginc )
	734	ENDIF
	735
	736
	737	ELSEIF ( ln_asmdin ) THEN
	738
	739	!--------------------------------------------------------------------
	740	! Direct Initialization
	741	!--------------------------------------------------------------------
	742
	743	IF ( kt == nitdin_r ) THEN
	744
	745	neuler = 0 ! Force Euler forward step
	746
	747	! Initialize the now fields with the background + increment
[3764]	748	IF (ln_temnofreeze) THEN
	749	! Do not apply negative increments if the temperature will fall below freezing
	750	WHERE(t_bkginc(:,:,:) > 0.0_wp .OR. &
	751	& tsn(:,:,:,jp_tem) + t_bkginc(:,:,:) > fzptnz(:,:,:) )
	752	tsn(:,:,:,jp_tem) = t_bkg(:,:,:) + t_bkginc(:,:,:)
	753	END WHERE
	754	ELSE
	755	tsn(:,:,:,jp_tem) = t_bkg(:,:,:) + t_bkginc(:,:,:)
	756	ENDIF
[2128]	757	IF (ln_salfix) THEN
[3764]	758	! Do not apply negative increments if the salinity will fall below a specified
	759	! minimum value salfixmin
	760	WHERE(s_bkginc(:,:,:) > 0.0_wp .OR. &
	761	& tsn(:,:,:,jp_sal) + s_bkginc(:,:,:) > salfixmin )
	762	tsn(:,:,:,jp_sal) = s_bkg(:,:,:) + s_bkginc(:,:,:)
	763	END WHERE
	764	ELSE
	765	tsn(:,:,:,jp_sal) = s_bkg(:,:,:) + s_bkginc(:,:,:)
[2128]	766	ENDIF
	767
[3764]	768	tsb(:,:,:,:) = tsn(:,:,:,:) ! Update before fields
[2128]	769
[2239]	770	CALL eos( tsb, rhd, rhop ) ! Before potential and in situ densities
[2128]	771
[2435]	772	IF( ln_zps .AND. .NOT. lk_c1d ) &
[3764]	773	& CALL zps_hde( nit000, jpts, tsb, & ! Partial steps: before horizontal derivative
	774	& gtsu, gtsv, rhd, & ! of T, S, rd at the bottom ocean level
[2239]	775	& gru , grv )
[2128]	776
[3764]	777	#if defined key_zdfkpp
	778	CALL eos( tsn, rhd ) ! Compute rhd
	779	#endif
	780
[2128]	781	DEALLOCATE( t_bkginc )
	782	DEALLOCATE( s_bkginc )
	783	DEALLOCATE( t_bkg )
	784	DEALLOCATE( s_bkg )
	785	ENDIF
[2392]	786	!
[2128]	787	ENDIF
[3764]	788	! Perhaps the following call should be in step
	789	IF ( ln_seaiceinc ) CALL seaice_asm_inc ( kt ) ! apply sea ice concentration increment
[2392]	790	!
[2128]	791	END SUBROUTINE tra_asm_inc
	792
[2392]	793
[2128]	794	SUBROUTINE dyn_asm_inc( kt )
	795	!!----------------------------------------------------------------------
	796	!! * ROUTINE dyn_asm_inc *
	797	!!
	798	!! ** Purpose : Apply the dynamics (u and v) assimilation increments.
	799	!!
	800	!! ** Method : Direct initialization or Incremental Analysis Updating.
	801	!!
	802	!! ** Action :
	803	!!----------------------------------------------------------------------
	804	INTEGER, INTENT(IN) :: kt ! Current time step
[2392]	805	!
[2128]	806	INTEGER :: jk
	807	INTEGER :: it
	808	REAL(wp) :: zincwgt ! IAU weight for current time step
[2392]	809	!!----------------------------------------------------------------------
[2128]	810
	811	IF ( ln_asmiau ) THEN
	812
	813	!--------------------------------------------------------------------
	814	! Incremental Analysis Updating
	815	!--------------------------------------------------------------------
	816
	817	IF ( ( kt >= nitiaustr_r ).AND.( kt <= nitiaufin_r ) ) THEN
	818
	819	it = kt - nit000 + 1
	820	zincwgt = wgtiau(it) / rdt ! IAU weight for the current time step
	821
	822	IF(lwp) THEN
	823	WRITE(numout,*)
	824	WRITE(numout,*) 'dyn_asm_inc : Dynamics IAU at time step = ', &
	825	& kt,' with IAU weight = ', wgtiau(it)
	826	WRITE(numout,*) '~~~~~~~~~~~~'
	827	ENDIF
	828
	829	! Update the dynamic tendencies
	830	DO jk = 1, jpkm1
	831	ua(:,:,jk) = ua(:,:,jk) + u_bkginc(:,:,jk) * zincwgt
	832	va(:,:,jk) = va(:,:,jk) + v_bkginc(:,:,jk) * zincwgt
	833	END DO
	834
	835	IF ( kt == nitiaufin_r ) THEN
	836	DEALLOCATE( u_bkginc )
	837	DEALLOCATE( v_bkginc )
	838	ENDIF
	839
	840	ENDIF
	841
	842	ELSEIF ( ln_asmdin ) THEN
	843
	844	!--------------------------------------------------------------------
	845	! Direct Initialization
	846	!--------------------------------------------------------------------
	847
	848	IF ( kt == nitdin_r ) THEN
	849
	850	neuler = 0 ! Force Euler forward step
	851
	852	! Initialize the now fields with the background + increment
	853	un(:,:,:) = u_bkg(:,:,:) + u_bkginc(:,:,:)
	854	vn(:,:,:) = v_bkg(:,:,:) + v_bkginc(:,:,:)
	855
	856	ub(:,:,:) = un(:,:,:) ! Update before fields
	857	vb(:,:,:) = vn(:,:,:)
	858
	859	DEALLOCATE( u_bkg )
	860	DEALLOCATE( v_bkg )
	861	DEALLOCATE( u_bkginc )
	862	DEALLOCATE( v_bkginc )
	863	ENDIF
[2392]	864	!
[2128]	865	ENDIF
[2392]	866	!
[2128]	867	END SUBROUTINE dyn_asm_inc
	868
[2392]	869
[2128]	870	SUBROUTINE ssh_asm_inc( kt )
	871	!!----------------------------------------------------------------------
	872	!! * ROUTINE ssh_asm_inc *
	873	!!
	874	!! ** Purpose : Apply the sea surface height assimilation increment.
	875	!!
	876	!! ** Method : Direct initialization or Incremental Analysis Updating.
	877	!!
	878	!! ** Action :
	879	!!----------------------------------------------------------------------
	880	INTEGER, INTENT(IN) :: kt ! Current time step
[2392]	881	!
[2128]	882	INTEGER :: it
[3764]	883	INTEGER :: jk
[2128]	884	REAL(wp) :: zincwgt ! IAU weight for current time step
[2392]	885	!!----------------------------------------------------------------------
[2128]	886
	887	IF ( ln_asmiau ) THEN
	888
	889	!--------------------------------------------------------------------
	890	! Incremental Analysis Updating
	891	!--------------------------------------------------------------------
	892
	893	IF ( ( kt >= nitiaustr_r ).AND.( kt <= nitiaufin_r ) ) THEN
	894
	895	it = kt - nit000 + 1
	896	zincwgt = wgtiau(it) / rdt ! IAU weight for the current time step
	897
	898	IF(lwp) THEN
	899	WRITE(numout,*)
	900	WRITE(numout,*) 'ssh_asm_inc : SSH IAU at time step = ', &
	901	& kt,' with IAU weight = ', wgtiau(it)
	902	WRITE(numout,*) '~~~~~~~~~~~~'
	903	ENDIF
	904
	905	! Save the tendency associated with the IAU weighted SSH increment
	906	! (applied in dynspg.*)
	907	#if defined key_asminc
	908	ssh_iau(:,:) = ssh_bkginc(:,:) * zincwgt
	909	#endif
	910	IF ( kt == nitiaufin_r ) THEN
	911	DEALLOCATE( ssh_bkginc )
	912	ENDIF
	913
	914	ENDIF
	915
	916	ELSEIF ( ln_asmdin ) THEN
	917
	918	!--------------------------------------------------------------------
	919	! Direct Initialization
	920	!--------------------------------------------------------------------
	921
	922	IF ( kt == nitdin_r ) THEN
	923
	924	neuler = 0 ! Force Euler forward step
	925
	926	! Initialize the now fields the background + increment
	927	sshn(:,:) = ssh_bkg(:,:) + ssh_bkginc(:,:)
	928
[3764]	929	! Update before fields
	930	sshb(:,:) = sshn(:,:)
[2128]	931
[3764]	932	IF( lk_vvl ) THEN
	933	DO jk = 1, jpk
	934	fse3t_b(:,:,jk) = fse3t_n(:,:,jk)
	935	END DO
	936	ENDIF
	937
[2128]	938	DEALLOCATE( ssh_bkg )
	939	DEALLOCATE( ssh_bkginc )
	940
	941	ENDIF
[2392]	942	!
[2128]	943	ENDIF
[2392]	944	!
[2128]	945	END SUBROUTINE ssh_asm_inc
	946
[3785]	947
[3764]	948	SUBROUTINE seaice_asm_inc( kt, kindic )
	949	!!----------------------------------------------------------------------
	950	!! * ROUTINE seaice_asm_inc *
	951	!!
	952	!! ** Purpose : Apply the sea ice assimilation increment.
	953	!!
	954	!! ** Method : Direct initialization or Incremental Analysis Updating.
	955	!!
	956	!! ** Action :
	957	!!
	958	!!----------------------------------------------------------------------
	959	IMPLICIT NONE
[3785]	960	!
	961	INTEGER, INTENT(in) :: kt ! Current time step
	962	INTEGER, INTENT(in), OPTIONAL :: kindic ! flag for disabling the deallocation
	963	!
	964	INTEGER :: it
	965	REAL(wp) :: zincwgt ! IAU weight for current time step
	966	#if defined key_lim2
	967	REAL(wp), DIMENSION(jpi,jpj) :: zofrld, zohicif, zseaicendg, zhicifinc ! LIM
	968	REAL(wp) :: zhicifmin = 0.5_wp ! ice minimum depth in metres
[3764]	969	#endif
[3785]	970	!!----------------------------------------------------------------------
[3764]	971
	972	IF ( ln_asmiau ) THEN
	973
	974	!--------------------------------------------------------------------
	975	! Incremental Analysis Updating
	976	!--------------------------------------------------------------------
	977
	978	IF ( ( kt >= nitiaustr_r ).AND.( kt <= nitiaufin_r ) ) THEN
	979
	980	it = kt - nit000 + 1
	981	zincwgt = wgtiau(it) ! IAU weight for the current time step
	982	! note this is not a tendency so should not be divided by rdt (as with the tracer and other increments)
	983
	984	IF(lwp) THEN
	985	WRITE(numout,*)
	986	WRITE(numout,*) 'seaice_asm_inc : sea ice conc IAU at time step = ', &
	987	& kt,' with IAU weight = ', wgtiau(it)
	988	WRITE(numout,*) '~~~~~~~~~~~~'
	989	ENDIF
	990
[3785]	991	! Sea-ice : LIM-3 case (to add)
[3764]	992
[3785]	993	#if defined key_lim2
	994	! Sea-ice : LIM-2 case
	995	zofrld (:,:) = frld(:,:)
	996	zohicif(:,:) = hicif(:,:)
	997	!
	998	frld = MIN( MAX( frld (:,:) - seaice_bkginc(:,:) * zincwgt, 0.0_wp), 1.0_wp)
[3764]	999	pfrld = MIN( MAX( pfrld(:,:) - seaice_bkginc(:,:) * zincwgt, 0.0_wp), 1.0_wp)
	1000	fr_i(:,:) = 1.0_wp - frld(:,:) ! adjust ice fraction
[3785]	1001	!
	1002	zseaicendg(:,:) = zofrld(:,:) - frld(:,:) ! find out actual sea ice nudge applied
	1003	!
[3764]	1004	! Nudge sea ice depth to bring it up to a required minimum depth
	1005	WHERE( zseaicendg(:,:) > 0.0_wp .AND. hicif(:,:) < zhicifmin )
	1006	zhicifinc(:,:) = (zhicifmin - hicif(:,:)) * zincwgt
	1007	ELSEWHERE
	1008	zhicifinc(:,:) = 0.0_wp
	1009	END WHERE
[3785]	1010	!
	1011	! nudge ice depth
	1012	hicif (:,:) = hicif (:,:) + zhicifinc(:,:)
	1013	phicif(:,:) = phicif(:,:) + zhicifinc(:,:)
	1014	!
	1015	! seaice salinity balancing (to add)
[3764]	1016	#endif
	1017
	1018	#if defined key_cice
[3785]	1019	! Sea-ice : CICE case. Pass ice increment tendency into CICE
[3764]	1020	ndaice_da(:,:) = seaice_bkginc(:,:) * zincwgt / rdt
	1021	#endif
	1022
	1023	IF ( kt == nitiaufin_r ) THEN
	1024	DEALLOCATE( seaice_bkginc )
	1025	ENDIF
	1026
	1027	ELSE
	1028
	1029	#if defined key_cice
[3785]	1030	! Sea-ice : CICE case. Zero ice increment tendency into CICE
[3764]	1031	ndaice_da(:,:) = 0.0_wp
	1032	#endif
	1033
	1034	ENDIF
	1035
	1036	ELSEIF ( ln_asmdin ) THEN
	1037
	1038	!--------------------------------------------------------------------
	1039	! Direct Initialization
	1040	!--------------------------------------------------------------------
	1041
	1042	IF ( kt == nitdin_r ) THEN
	1043
	1044	neuler = 0 ! Force Euler forward step
	1045
[3785]	1046	! Sea-ice : LIM-3 case (to add)
[3764]	1047
[3785]	1048	#if defined key_lim2
	1049	! Sea-ice : LIM-2 case.
[3764]	1050	zofrld(:,:)=frld(:,:)
	1051	zohicif(:,:)=hicif(:,:)
[3785]	1052	!
[3764]	1053	! Initialize the now fields the background + increment
[3785]	1054	frld (:,:) = MIN( MAX( frld(:,:) - seaice_bkginc(:,:), 0.0_wp), 1.0_wp)
[3764]	1055	pfrld(:,:) = frld(:,:)
[3785]	1056	fr_i (:,:) = 1.0_wp - frld(:,:) ! adjust ice fraction
	1057	zseaicendg(:,:) = zofrld(:,:) - frld(:,:) ! find out actual sea ice nudge applied
	1058	!
[3764]	1059	! Nudge sea ice depth to bring it up to a required minimum depth
	1060	WHERE( zseaicendg(:,:) > 0.0_wp .AND. hicif(:,:) < zhicifmin )
	1061	zhicifinc(:,:) = (zhicifmin - hicif(:,:)) * zincwgt
	1062	ELSEWHERE
	1063	zhicifinc(:,:) = 0.0_wp
	1064	END WHERE
[3785]	1065	!
	1066	! nudge ice depth
	1067	hicif (:,:) = hicif (:,:) + zhicifinc(:,:)
	1068	phicif(:,:) = phicif(:,:)
	1069	!
	1070	! seaice salinity balancing (to add)
[3764]	1071	#endif
	1072
	1073	#if defined key_cice
[3785]	1074	! Sea-ice : CICE case. Pass ice increment tendency into CICE - is this correct?
[3764]	1075	ndaice_da(:,:) = seaice_bkginc(:,:) / rdt
	1076	#endif
	1077	IF ( .NOT. PRESENT(kindic) ) THEN
	1078	DEALLOCATE( seaice_bkginc )
	1079	END IF
	1080
	1081	ELSE
	1082
	1083	#if defined key_cice
[3785]	1084	! Sea-ice : CICE case. Zero ice increment tendency into CICE
[3764]	1085	ndaice_da(:,:) = 0.0_wp
	1086	#endif
	1087
	1088	ENDIF
	1089
[3785]	1090	!#if defined defined key_lim2 \|\| defined key_cice
[3764]	1091	!
	1092	! IF (ln_seaicebal ) THEN
	1093	! !! balancing salinity increments
	1094	! !! simple case from limflx.F90 (doesn't include a mass flux)
	1095	! !! assumption is that as ice concentration is reduced or increased
	1096	! !! the snow and ice depths remain constant
	1097	! !! note that snow is being created where ice concentration is being increased
	1098	! !! - could be more sophisticated and
	1099	! !! not do this (but would need to alter h_snow)
	1100	!
	1101	! usave(:,:,:)=sb(:,:,:) ! use array as a temporary store
	1102	!
	1103	! DO jj = 1, jpj
	1104	! DO ji = 1, jpi
	1105	! ! calculate change in ice and snow mass per unit area
	1106	! ! positive values imply adding salt to the ocean (results from ice formation)
	1107	! ! fwf : ice formation and melting
	1108	!
	1109	! zfons = ( -nfresh_da(ji,jj)soce + nfsalt_da(ji,jj) )rdt
	1110	!
	1111	! ! change salinity down to mixed layer depth
	1112	! mld=hmld_kara(ji,jj)
	1113	!
	1114	! ! prevent small mld
	1115	! ! less than 10m can cause salinity instability
	1116	! IF (mld < 10) mld=10
	1117	!
	1118	! ! set to bottom of a level
	1119	! DO jk = jpk-1, 2, -1
	1120	! IF ((mld > gdepw(ji,jj,jk)) .and. (mld < gdepw(ji,jj,jk+1))) THEN
	1121	! mld=gdepw(ji,jj,jk+1)
	1122	! jkmax=jk
	1123	! ENDIF
	1124	! ENDDO
	1125	!
	1126	! ! avoid applying salinity balancing in shallow water or on land
	1127	! !
	1128	!
	1129	! ! dsal_ocn (psu kg m^-2) / (kg m^-3 * m)
	1130	!
	1131	! dsal_ocn=0.0_wp
	1132	! sal_thresh=5.0_wp ! minimum salinity threshold for salinity balancing
	1133	!
	1134	! if (tmask(ji,jj,1) > 0 .AND. tmask(ji,jj,jkmax) > 0 ) &
	1135	! dsal_ocn = zfons / (rhop(ji,jj,1) * mld)
	1136	!
	1137	! ! put increments in for levels in the mixed layer
	1138	! ! but prevent salinity below a threshold value
	1139	!
	1140	! DO jk = 1, jkmax
	1141	!
	1142	! IF (dsal_ocn > 0.0_wp .or. sb(ji,jj,jk)+dsal_ocn > sal_thresh) THEN
	1143	! sb(ji,jj,jk) = sb(ji,jj,jk) + dsal_ocn
	1144	! sn(ji,jj,jk) = sn(ji,jj,jk) + dsal_ocn
	1145	! ENDIF
	1146	!
	1147	! ENDDO
	1148	!
	1149	! ! ! salt exchanges at the ice/ocean interface
	1150	! ! zpmess = zfons / rdt_ice ! rdt_ice is ice timestep
	1151	! !
	1152	! !! Adjust fsalt. A +ve fsalt means adding salt to ocean
	1153	! !! fsalt(ji,jj) = fsalt(ji,jj) + zpmess ! adjust fsalt
	1154	! !!
	1155	! !! emps(ji,jj) = emps(ji,jj) + zpmess ! or adjust emps (see icestp1d)
	1156	! !! ! E-P (kg m-2 s-2)
	1157	! ! emp(ji,jj) = emp(ji,jj) + zpmess ! E-P (kg m-2 s-2)
	1158	! ENDDO !ji
	1159	! ENDDO !jj!
	1160	!
	1161	! ENDIF !ln_seaicebal
	1162	!
	1163	!#endif
	1164
	1165	ENDIF
	1166
	1167	END SUBROUTINE seaice_asm_inc
[3785]	1168
[2392]	1169	!!======================================================================
[2128]	1170	END MODULE asminc

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