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asminc.F90 in branches/2017/dev_merge_2017/NEMOGCM/NEMO/OPA_SRC/ASM – NEMO

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source: branches/2017/dev_merge_2017/NEMOGCM/NEMO/OPA_SRC/ASM/asminc.F90 @ 9254

Last change on this file since 9254 was 9254, checked in by smasson, 6 years ago
dev_merge_2017: missing use in asminc
Property svn:keywords set to `Id`
File size: 47.7 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
[6140]	13	!! ! 2014-09 (D. Lea) Local calc_date removed use routine from OBS
	14	!! ! 2015-11 (D. Lea) Handle non-zero initial time of day
[2392]	15	!!----------------------------------------------------------------------
[2128]	16
	17	!!----------------------------------------------------------------------
[3785]	18	!! asm_inc_init : Initialize the increment arrays and IAU weights
	19	!! tra_asm_inc : Apply the tracer (T and S) increments
	20	!! dyn_asm_inc : Apply the dynamic (u and v) increments
	21	!! ssh_asm_inc : Apply the SSH increment
[9023]	22	!! ssh_asm_div : Apply divergence associated with SSH increment
[3785]	23	!! seaice_asm_inc : Apply the seaice increment
[2128]	24	!!----------------------------------------------------------------------
[9019]	25	USE oce ! Dynamics and active tracers defined in memory
	26	USE par_oce ! Ocean space and time domain variables
	27	USE dom_oce ! Ocean space and time domain
	28	USE domvvl ! domain: variable volume level
	29	USE ldfdyn ! lateral diffusion: eddy viscosity coefficients
	30	USE eosbn2 ! Equation of state - in situ and potential density
	31	USE zpshde ! Partial step : Horizontal Derivative
	32	USE asmpar ! Parameters for the assmilation interface
[9254]	33	USE asmbkg !
[9019]	34	USE c1d ! 1D initialization
	35	USE sbc_oce ! Surface boundary condition variables.
	36	USE diaobs , ONLY : calc_date ! Compute the calendar date on a given step
	37	#if defined key_lim3
	38	USE ice , ONLY : hm_i, at_i, at_i_b
[3764]	39	#endif
[9019]	40	!
	41	USE in_out_manager ! I/O manager
	42	USE iom ! Library to read input files
	43	USE lib_mpp ! MPP library
[2128]	44
	45	IMPLICIT NONE
	46	PRIVATE
[2392]	47
	48	PUBLIC asm_inc_init !: Initialize the increment arrays and IAU weights
	49	PUBLIC tra_asm_inc !: Apply the tracer (T and S) increments
	50	PUBLIC dyn_asm_inc !: Apply the dynamic (u and v) increments
	51	PUBLIC ssh_asm_inc !: Apply the SSH increment
[9023]	52	PUBLIC ssh_asm_div !: Apply the SSH divergence
[3764]	53	PUBLIC seaice_asm_inc !: Apply the seaice increment
[2128]	54
	55	#if defined key_asminc
[2392]	56	LOGICAL, PUBLIC, PARAMETER :: lk_asminc = .TRUE. !: Logical switch for assimilation increment interface
[2128]	57	#else
[2392]	58	LOGICAL, PUBLIC, PARAMETER :: lk_asminc = .FALSE. !: No assimilation increments
[2128]	59	#endif
[5836]	60	LOGICAL, PUBLIC :: ln_bkgwri !: No output of the background state fields
	61	LOGICAL, PUBLIC :: ln_asmiau !: No applying forcing with an assimilation increment
	62	LOGICAL, PUBLIC :: ln_asmdin !: No direct initialization
	63	LOGICAL, PUBLIC :: ln_trainc !: No tracer (T and S) assimilation increments
	64	LOGICAL, PUBLIC :: ln_dyninc !: No dynamics (u and v) assimilation increments
	65	LOGICAL, PUBLIC :: ln_sshinc !: No sea surface height assimilation increment
	66	LOGICAL, PUBLIC :: ln_seaiceinc !: No sea ice concentration increment
	67	LOGICAL, PUBLIC :: ln_salfix !: Apply minimum salinity check
[3764]	68	LOGICAL, PUBLIC :: ln_temnofreeze = .FALSE. !: Don't allow the temperature to drop below freezing
[5836]	69	INTEGER, PUBLIC :: nn_divdmp !: Apply divergence damping filter nn_divdmp times
[2128]	70
[2392]	71	REAL(wp), PUBLIC, DIMENSION(:,:,:), ALLOCATABLE :: t_bkg , s_bkg !: Background temperature and salinity
	72	REAL(wp), PUBLIC, DIMENSION(:,:,:), ALLOCATABLE :: u_bkg , v_bkg !: Background u- & v- velocity components
	73	REAL(wp), PUBLIC, DIMENSION(:,:,:), ALLOCATABLE :: t_bkginc, s_bkginc !: Increment to the background T & S
	74	REAL(wp), PUBLIC, DIMENSION(:,:,:), ALLOCATABLE :: u_bkginc, v_bkginc !: Increment to the u- & v-components
	75	REAL(wp), PUBLIC, DIMENSION(:) , ALLOCATABLE :: wgtiau !: IAU weights for each time step
[2128]	76	#if defined key_asminc
[9213]	77	REAL(wp), PUBLIC, DIMENSION(:,:) , ALLOCATABLE :: ssh_iau !: IAU-weighted sea surface height increment
[2128]	78	#endif
[2392]	79	! !!! time steps relative to the cycle interval [0,nitend-nit000-1]
	80	INTEGER , PUBLIC :: nitbkg !: Time step of the background state used in the Jb term
	81	INTEGER , PUBLIC :: nitdin !: Time step of the background state for direct initialization
	82	INTEGER , PUBLIC :: nitiaustr !: Time step of the start of the IAU interval
	83	INTEGER , PUBLIC :: nitiaufin !: Time step of the end of the IAU interval
	84	!
	85	INTEGER , PUBLIC :: niaufn !: Type of IAU weighing function: = 0 Constant weighting
	86	! !: = 1 Linear hat-like, centred in middle of IAU interval
	87	REAL(wp), PUBLIC :: salfixmin !: Ensure that the salinity is larger than this value if (ln_salfix)
[2128]	88
[2392]	89	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: ssh_bkg, ssh_bkginc ! Background sea surface height and its increment
[3764]	90	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: seaice_bkginc ! Increment to the background sea ice conc
[8030]	91	#if defined key_cice && defined key_asminc
	92	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: ndaice_da ! ice increment tendency into CICE
	93	#endif
[2128]	94
[3294]	95	!! * Substitutions
	96	# include "vectopt_loop_substitute.h90"
[2287]	97	!!----------------------------------------------------------------------
[6140]	98	!! NEMO/OPA 3.7 , NEMO Consortium (2015)
[2287]	99	!! $Id$
[2392]	100	!! Software governed by the CeCILL licence (NEMOGCM/NEMO_CeCILL.txt)
[2287]	101	!!----------------------------------------------------------------------
[2128]	102	CONTAINS
	103
	104	SUBROUTINE asm_inc_init
	105	!!----------------------------------------------------------------------
	106	!! * ROUTINE asm_inc_init *
	107	!!
	108	!! ** Purpose : Initialize the assimilation increment and IAU weights.
	109	!!
	110	!! ** Method : Initialize the assimilation increment and IAU weights.
	111	!!
	112	!! ** Action :
	113	!!----------------------------------------------------------------------
[4990]	114	INTEGER :: ji, jj, jk, jt ! dummy loop indices
	115	INTEGER :: imid, inum ! local integers
	116	INTEGER :: ios ! Local integer output status for namelist read
[2128]	117	INTEGER :: iiauper ! Number of time steps in the IAU period
	118	INTEGER :: icycper ! Number of time steps in the cycle
[6140]	119	REAL(KIND=dp) :: ditend_date ! Date YYYYMMDD.HHMMSS of final time step
	120	REAL(KIND=dp) :: ditbkg_date ! Date YYYYMMDD.HHMMSS of background time step for Jb term
	121	REAL(KIND=dp) :: ditdin_date ! Date YYYYMMDD.HHMMSS of background time step for DI
	122	REAL(KIND=dp) :: ditiaustr_date ! Date YYYYMMDD.HHMMSS of IAU interval start time step
	123	REAL(KIND=dp) :: ditiaufin_date ! Date YYYYMMDD.HHMMSS of IAU interval final time step
	124
[2128]	125	REAL(wp) :: znorm ! Normalization factor for IAU weights
[4990]	126	REAL(wp) :: ztotwgt ! Value of time-integrated IAU weights (should be equal to one)
[2128]	127	REAL(wp) :: z_inc_dateb ! Start date of interval on which increment is valid
	128	REAL(wp) :: z_inc_datef ! End date of interval on which increment is valid
	129	REAL(wp) :: zdate_bkg ! Date in background state file for DI
	130	REAL(wp) :: zdate_inc ! Time axis in increments file
[4990]	131	!
[9019]	132	REAL(wp), ALLOCATABLE, DIMENSION(:,:) :: zhdiv ! 2D workspace
[2392]	133	!!
[3764]	134	NAMELIST/nam_asminc/ ln_bkgwri, &
[2392]	135	& ln_trainc, ln_dyninc, ln_sshinc, &
	136	& ln_asmdin, ln_asmiau, &
	137	& nitbkg, nitdin, nitiaustr, nitiaufin, niaufn, &
[4990]	138	& ln_salfix, salfixmin, nn_divdmp
[2392]	139	!!----------------------------------------------------------------------
[2128]	140
	141	!-----------------------------------------------------------------------
	142	! Read Namelist nam_asminc : assimilation increment interface
	143	!-----------------------------------------------------------------------
[5836]	144	ln_seaiceinc = .FALSE.
[3764]	145	ln_temnofreeze = .FALSE.
[2128]	146
[4147]	147	REWIND( numnam_ref ) ! Namelist nam_asminc in reference namelist : Assimilation increment
	148	READ ( numnam_ref, nam_asminc, IOSTAT = ios, ERR = 901)
[9168]	149	901 IF( ios /= 0 ) CALL ctl_nam ( ios , 'nam_asminc in reference namelist', lwp )
[4147]	150	REWIND( numnam_cfg ) ! Namelist nam_asminc in configuration namelist : Assimilation increment
	151	READ ( numnam_cfg, nam_asminc, IOSTAT = ios, ERR = 902 )
[9168]	152	902 IF( ios > 0 ) CALL ctl_nam ( ios , 'nam_asminc in configuration namelist', lwp )
[4624]	153	IF(lwm) WRITE ( numond, nam_asminc )
[4147]	154
[2128]	155	! Control print
	156	IF(lwp) THEN
	157	WRITE(numout,*)
	158	WRITE(numout,*) 'asm_inc_init : Assimilation increment initialization :'
	159	WRITE(numout,*) '~~~~~~~~~~~~'
[2392]	160	WRITE(numout,*) ' Namelist namasm : set assimilation increment parameters'
	161	WRITE(numout,*) ' Logical switch for writing out background state ln_bkgwri = ', ln_bkgwri
	162	WRITE(numout,*) ' Logical switch for applying tracer increments ln_trainc = ', ln_trainc
	163	WRITE(numout,*) ' Logical switch for applying velocity increments ln_dyninc = ', ln_dyninc
	164	WRITE(numout,*) ' Logical switch for applying SSH increments ln_sshinc = ', ln_sshinc
	165	WRITE(numout,*) ' Logical switch for Direct Initialization (DI) ln_asmdin = ', ln_asmdin
[3764]	166	WRITE(numout,*) ' Logical switch for applying sea ice increments ln_seaiceinc = ', ln_seaiceinc
[2392]	167	WRITE(numout,*) ' Logical switch for Incremental Analysis Updating (IAU) ln_asmiau = ', ln_asmiau
	168	WRITE(numout,*) ' Timestep of background in [0,nitend-nit000-1] nitbkg = ', nitbkg
	169	WRITE(numout,*) ' Timestep of background for DI in [0,nitend-nit000-1] nitdin = ', nitdin
	170	WRITE(numout,*) ' Timestep of start of IAU interval in [0,nitend-nit000-1] nitiaustr = ', nitiaustr
	171	WRITE(numout,*) ' Timestep of end of IAU interval in [0,nitend-nit000-1] nitiaufin = ', nitiaufin
	172	WRITE(numout,*) ' Type of IAU weighting function niaufn = ', niaufn
	173	WRITE(numout,*) ' Logical switch for ensuring that the sa > salfixmin ln_salfix = ', ln_salfix
	174	WRITE(numout,*) ' Minimum salinity after applying the increments salfixmin = ', salfixmin
[2128]	175	ENDIF
	176
[9019]	177	nitbkg_r = nitbkg + nit000 - 1 ! Background time referenced to nit000
	178	nitdin_r = nitdin + nit000 - 1 ! Background time for DI referenced to nit000
	179	nitiaustr_r = nitiaustr + nit000 - 1 ! Start of IAU interval referenced to nit000
	180	nitiaufin_r = nitiaufin + nit000 - 1 ! End of IAU interval referenced to nit000
[2128]	181
[9019]	182	iiauper = nitiaufin_r - nitiaustr_r + 1 ! IAU interval length
	183	icycper = nitend - nit000 + 1 ! Cycle interval length
[2128]	184
[9019]	185	CALL calc_date( nitend , ditend_date ) ! Date of final time step
	186	CALL calc_date( nitbkg_r , ditbkg_date ) ! Background time for Jb referenced to ndate0
	187	CALL calc_date( nitdin_r , ditdin_date ) ! Background time for DI referenced to ndate0
	188	CALL calc_date( nitiaustr_r, ditiaustr_date ) ! IAU start time referenced to ndate0
	189	CALL calc_date( nitiaufin_r, ditiaufin_date ) ! IAU end time referenced to ndate0
[6140]	190
[2128]	191	IF(lwp) THEN
	192	WRITE(numout,*)
	193	WRITE(numout,*) ' Time steps referenced to current cycle:'
	194	WRITE(numout,*) ' iitrst = ', nit000 - 1
	195	WRITE(numout,*) ' nit000 = ', nit000
	196	WRITE(numout,*) ' nitend = ', nitend
	197	WRITE(numout,*) ' nitbkg_r = ', nitbkg_r
	198	WRITE(numout,*) ' nitdin_r = ', nitdin_r
	199	WRITE(numout,*) ' nitiaustr_r = ', nitiaustr_r
	200	WRITE(numout,*) ' nitiaufin_r = ', nitiaufin_r
	201	WRITE(numout,*)
	202	WRITE(numout,*) ' Dates referenced to current cycle:'
	203	WRITE(numout,*) ' ndastp = ', ndastp
	204	WRITE(numout,*) ' ndate0 = ', ndate0
[6140]	205	WRITE(numout,*) ' nn_time0 = ', nn_time0
	206	WRITE(numout,*) ' ditend_date = ', ditend_date
	207	WRITE(numout,*) ' ditbkg_date = ', ditbkg_date
	208	WRITE(numout,*) ' ditdin_date = ', ditdin_date
	209	WRITE(numout,*) ' ditiaustr_date = ', ditiaustr_date
	210	WRITE(numout,*) ' ditiaufin_date = ', ditiaufin_date
[2128]	211	ENDIF
	212
	213
	214	IF ( ( ln_asmdin ).AND.( ln_asmiau ) ) &
	215	& CALL ctl_stop( ' ln_asmdin and ln_asmiau :', &
	216	& ' Choose Direct Initialization OR Incremental Analysis Updating')
	217
	218	IF ( ( ( .NOT. ln_asmdin ).AND.( .NOT. ln_asmiau ) ) &
[3764]	219	.AND.( ( ln_trainc ).OR.( ln_dyninc ).OR.( ln_sshinc ) .OR. ( ln_seaiceinc) )) &
	220	& CALL ctl_stop( ' One or more of ln_trainc, ln_dyninc, ln_sshinc and ln_seaiceinc is set to .true.', &
[2128]	221	& ' but ln_asmdin and ln_asmiau are both set to .false. :', &
	222	& ' Inconsistent options')
	223
	224	IF ( ( niaufn /= 0 ).AND.( niaufn /= 1 ) ) &
	225	& CALL ctl_stop( ' niaufn /= 0 or niaufn /=1 :', &
	226	& ' Type IAU weighting function is invalid')
	227
[3764]	228	IF ( ( .NOT. ln_trainc ).AND.( .NOT. ln_dyninc ).AND.( .NOT. ln_sshinc ).AND.( .NOT. ln_seaiceinc ) &
[2128]	229	& ) &
[3764]	230	& CALL ctl_warn( ' ln_trainc, ln_dyninc, ln_sshinc and ln_seaiceinc are set to .false. :', &
[2128]	231	& ' The assimilation increments are not applied')
	232
	233	IF ( ( ln_asmiau ).AND.( nitiaustr == nitiaufin ) ) &
	234	& CALL ctl_stop( ' nitiaustr = nitiaufin :', &
	235	& ' IAU interval is of zero length')
	236
	237	IF ( ( ln_asmiau ).AND.( ( nitiaustr_r < nit000 ).OR.( nitiaufin_r > nitend ) ) ) &
	238	& CALL ctl_stop( ' nitiaustr or nitiaufin :', &
	239	& ' IAU starting or final time step is outside the cycle interval', &
	240	& ' Valid range nit000 to nitend')
	241
	242	IF ( ( nitbkg_r < nit000 - 1 ).OR.( nitbkg_r > nitend ) ) &
	243	& CALL ctl_stop( ' nitbkg :', &
	244	& ' Background time step is outside the cycle interval')
	245
	246	IF ( ( nitdin_r < nit000 - 1 ).OR.( nitdin_r > nitend ) ) &
	247	& CALL ctl_stop( ' nitdin :', &
	248	& ' Background time step for Direct Initialization is outside', &
	249	& ' the cycle interval')
	250
	251	IF ( nstop > 0 ) RETURN ! if there are any errors then go no further
	252
	253	!--------------------------------------------------------------------
	254	! Initialize the Incremental Analysis Updating weighting function
	255	!--------------------------------------------------------------------
	256
[9213]	257	IF( ln_asmiau ) THEN
	258	!
[2128]	259	ALLOCATE( wgtiau( icycper ) )
[9213]	260	!
[9019]	261	wgtiau(:) = 0._wp
[9213]	262	!
	263	! !---------------------------------------------------------
	264	IF( niaufn == 0 ) THEN ! Constant IAU forcing
	265	! !---------------------------------------------------------
[2128]	266	DO jt = 1, iiauper
	267	wgtiau(jt+nitiaustr-1) = 1.0 / REAL( iiauper )
	268	END DO
[9213]	269	! !---------------------------------------------------------
	270	ELSEIF ( niaufn == 1 ) THEN ! Linear hat-like, centred in middle of IAU interval
	271	! !---------------------------------------------------------
[2128]	272	! Compute the normalization factor
[9213]	273	znorm = 0._wp
	274	IF( MOD( iiauper, 2 ) == 0 ) THEN ! Even number of time steps in IAU interval
[2128]	275	imid = iiauper / 2
	276	DO jt = 1, imid
	277	znorm = znorm + REAL( jt )
	278	END DO
	279	znorm = 2.0 * znorm
[9213]	280	ELSE ! Odd number of time steps in IAU interval
[2128]	281	imid = ( iiauper + 1 ) / 2
	282	DO jt = 1, imid - 1
	283	znorm = znorm + REAL( jt )
	284	END DO
	285	znorm = 2.0 * znorm + REAL( imid )
	286	ENDIF
	287	znorm = 1.0 / znorm
[9213]	288	!
[2128]	289	DO jt = 1, imid - 1
	290	wgtiau(jt+nitiaustr-1) = REAL( jt ) * znorm
	291	END DO
	292	DO jt = imid, iiauper
	293	wgtiau(jt+nitiaustr-1) = REAL( iiauper - jt + 1 ) * znorm
	294	END DO
[9213]	295	!
[2128]	296	ENDIF
	297
	298	! Test that the integral of the weights over the weighting interval equals 1
	299	IF(lwp) THEN
	300	WRITE(numout,*)
	301	WRITE(numout,*) 'asm_inc_init : IAU weights'
	302	WRITE(numout,*) '~~~~~~~~~~~~'
	303	WRITE(numout,*) ' time step IAU weight'
	304	WRITE(numout,*) ' ========= ====================='
	305	ztotwgt = 0.0
	306	DO jt = 1, icycper
	307	ztotwgt = ztotwgt + wgtiau(jt)
	308	WRITE(numout,*) ' ', jt, ' ', wgtiau(jt)
	309	END DO
	310	WRITE(numout,*) ' ==================================='
	311	WRITE(numout,*) ' Time-integrated weight = ', ztotwgt
	312	WRITE(numout,*) ' ==================================='
	313	ENDIF
	314
	315	ENDIF
	316
	317	!--------------------------------------------------------------------
	318	! Allocate and initialize the increment arrays
	319	!--------------------------------------------------------------------
	320
[9213]	321	ALLOCATE( t_bkginc (jpi,jpj,jpk) ) ; t_bkginc (:,:,:) = 0._wp
	322	ALLOCATE( s_bkginc (jpi,jpj,jpk) ) ; s_bkginc (:,:,:) = 0._wp
	323	ALLOCATE( u_bkginc (jpi,jpj,jpk) ) ; u_bkginc (:,:,:) = 0._wp
	324	ALLOCATE( v_bkginc (jpi,jpj,jpk) ) ; v_bkginc (:,:,:) = 0._wp
	325	ALLOCATE( ssh_bkginc (jpi,jpj) ) ; ssh_bkginc (:,:) = 0._wp
	326	ALLOCATE( seaice_bkginc(jpi,jpj) ) ; seaice_bkginc(:,:) = 0._wp
[2128]	327	#if defined key_asminc
[9213]	328	ALLOCATE( ssh_iau (jpi,jpj) ) ; ssh_iau (:,:) = 0._wp
[2128]	329	#endif
[8030]	330	#if defined key_cice && defined key_asminc
[9213]	331	ALLOCATE( ndaice_da (jpi,jpj) ) ; ndaice_da (:,:) = 0._wp
[8030]	332	#endif
[9213]	333	!
	334	IF ( ln_trainc .OR. ln_dyninc .OR. & !--------------------------------------
	335	& ln_sshinc .OR. ln_seaiceinc ) THEN ! Read the increments from file
	336	! !--------------------------------------
[2128]	337	CALL iom_open( c_asminc, inum )
[9213]	338	!
	339	CALL iom_get( inum, 'time' , zdate_inc )
[2128]	340	CALL iom_get( inum, 'z_inc_dateb', z_inc_dateb )
	341	CALL iom_get( inum, 'z_inc_datef', z_inc_datef )
	342	z_inc_dateb = zdate_inc
	343	z_inc_datef = zdate_inc
[9213]	344	!
[2128]	345	IF(lwp) THEN
	346	WRITE(numout,*)
[9213]	347	WRITE(numout,*) 'asm_inc_init : Assimilation increments valid between dates ', z_inc_dateb,' and ', z_inc_datef
[2128]	348	WRITE(numout,*) '~~~~~~~~~~~~'
	349	ENDIF
[9213]	350	!
	351	IF ( ( z_inc_dateb < ndastp + nn_time0*0.0001_wp ) .OR. &
	352	& ( z_inc_datef > ditend_date ) ) &
	353	& CALL ctl_warn( ' Validity time of assimilation increments is ', &
	354	& ' outside the assimilation interval' )
[2128]	355
[6140]	356	IF ( ( ln_asmdin ).AND.( zdate_inc /= ditdin_date ) ) &
[2128]	357	& CALL ctl_warn( ' Validity time of assimilation increments does ', &
	358	& ' not agree with Direct Initialization time' )
	359
	360	IF ( ln_trainc ) THEN
	361	CALL iom_get( inum, jpdom_autoglo, 'bckint', t_bkginc, 1 )
	362	CALL iom_get( inum, jpdom_autoglo, 'bckins', s_bkginc, 1 )
	363	! Apply the masks
	364	t_bkginc(:,:,:) = t_bkginc(:,:,:) * tmask(:,:,:)
	365	s_bkginc(:,:,:) = s_bkginc(:,:,:) * tmask(:,:,:)
	366	! Set missing increments to 0.0 rather than 1e+20
	367	! to allow for differences in masks
	368	WHERE( ABS( t_bkginc(:,:,:) ) > 1.0e+10 ) t_bkginc(:,:,:) = 0.0
	369	WHERE( ABS( s_bkginc(:,:,:) ) > 1.0e+10 ) s_bkginc(:,:,:) = 0.0
	370	ENDIF
	371
	372	IF ( ln_dyninc ) THEN
	373	CALL iom_get( inum, jpdom_autoglo, 'bckinu', u_bkginc, 1 )
	374	CALL iom_get( inum, jpdom_autoglo, 'bckinv', v_bkginc, 1 )
	375	! Apply the masks
	376	u_bkginc(:,:,:) = u_bkginc(:,:,:) * umask(:,:,:)
	377	v_bkginc(:,:,:) = v_bkginc(:,:,:) * vmask(:,:,:)
	378	! Set missing increments to 0.0 rather than 1e+20
	379	! to allow for differences in masks
	380	WHERE( ABS( u_bkginc(:,:,:) ) > 1.0e+10 ) u_bkginc(:,:,:) = 0.0
	381	WHERE( ABS( v_bkginc(:,:,:) ) > 1.0e+10 ) v_bkginc(:,:,:) = 0.0
	382	ENDIF
	383
	384	IF ( ln_sshinc ) THEN
	385	CALL iom_get( inum, jpdom_autoglo, 'bckineta', ssh_bkginc, 1 )
	386	! Apply the masks
	387	ssh_bkginc(:,:) = ssh_bkginc(:,:) * tmask(:,:,1)
	388	! Set missing increments to 0.0 rather than 1e+20
	389	! to allow for differences in masks
	390	WHERE( ABS( ssh_bkginc(:,:) ) > 1.0e+10 ) ssh_bkginc(:,:) = 0.0
	391	ENDIF
	392
[3764]	393	IF ( ln_seaiceinc ) THEN
	394	CALL iom_get( inum, jpdom_autoglo, 'bckinseaice', seaice_bkginc, 1 )
	395	! Apply the masks
	396	seaice_bkginc(:,:) = seaice_bkginc(:,:) * tmask(:,:,1)
	397	! Set missing increments to 0.0 rather than 1e+20
	398	! to allow for differences in masks
	399	WHERE( ABS( seaice_bkginc(:,:) ) > 1.0e+10 ) seaice_bkginc(:,:) = 0.0
	400	ENDIF
[9213]	401	!
[2128]	402	CALL iom_close( inum )
[9213]	403	!
[2128]	404	ENDIF
[9213]	405	!
	406	! !--------------------------------------
	407	IF ( ln_dyninc .AND. nn_divdmp > 0 ) THEN ! Apply divergence damping filter
	408	! !--------------------------------------
[9019]	409	ALLOCATE( zhdiv(jpi,jpj) )
[5836]	410	!
	411	DO jt = 1, nn_divdmp
	412	!
[9019]	413	DO jk = 1, jpkm1 ! zhdiv = e1e1 * div
	414	zhdiv(:,:) = 0._wp
[3764]	415	DO jj = 2, jpjm1
	416	DO ji = fs_2, fs_jpim1 ! vector opt.
[9019]	417	zhdiv(ji,jj) = ( e2u(ji ,jj) * e3u_n(ji ,jj,jk) * u_bkginc(ji ,jj,jk) &
	418	& - e2u(ji-1,jj) * e3u_n(ji-1,jj,jk) * u_bkginc(ji-1,jj,jk) &
	419	& + e1v(ji,jj ) * e3v_n(ji,jj ,jk) * v_bkginc(ji,jj ,jk) &
	420	& - e1v(ji,jj-1) * e3v_n(ji,jj-1,jk) * v_bkginc(ji,jj-1,jk) ) / e3t_n(ji,jj,jk)
[3764]	421	END DO
[3294]	422	END DO
[9019]	423	CALL lbc_lnk( zhdiv, 'T', 1. ) ! lateral boundary cond. (no sign change)
[5836]	424	!
[3764]	425	DO jj = 2, jpjm1
	426	DO ji = fs_2, fs_jpim1 ! vector opt.
[6140]	427	u_bkginc(ji,jj,jk) = u_bkginc(ji,jj,jk) &
[9019]	428	& + 0.2_wp * ( zhdiv(ji+1,jj) - zhdiv(ji ,jj) ) * r1_e1u(ji,jj) * umask(ji,jj,jk)
[6140]	429	v_bkginc(ji,jj,jk) = v_bkginc(ji,jj,jk) &
[9019]	430	& + 0.2_wp * ( zhdiv(ji,jj+1) - zhdiv(ji,jj ) ) * r1_e2v(ji,jj) * vmask(ji,jj,jk)
[3764]	431	END DO
[3294]	432	END DO
	433	END DO
[5836]	434	!
[3764]	435	END DO
[5836]	436	!
[9019]	437	DEALLOCATE( zhdiv )
[5836]	438	!
[3294]	439	ENDIF
[9213]	440	!
	441	! !-----------------------------------------------------
	442	IF ( ln_asmdin ) THEN ! Allocate and initialize the background state arrays
	443	! !-----------------------------------------------------
[5836]	444	!
[9213]	445	ALLOCATE( t_bkg (jpi,jpj,jpk) ) ; t_bkg (:,:,:) = 0._wp
	446	ALLOCATE( s_bkg (jpi,jpj,jpk) ) ; s_bkg (:,:,:) = 0._wp
	447	ALLOCATE( u_bkg (jpi,jpj,jpk) ) ; u_bkg (:,:,:) = 0._wp
	448	ALLOCATE( v_bkg (jpi,jpj,jpk) ) ; v_bkg (:,:,:) = 0._wp
	449	ALLOCATE( ssh_bkg(jpi,jpj) ) ; ssh_bkg(:,:) = 0._wp
[5836]	450	!
	451	!
[2128]	452	!--------------------------------------------------------------------
	453	! Read from file the background state at analysis time
	454	!--------------------------------------------------------------------
[5836]	455	!
[2128]	456	CALL iom_open( c_asmdin, inum )
[5836]	457	!
[3764]	458	CALL iom_get( inum, 'rdastp', zdate_bkg )
[5836]	459	!
[2128]	460	IF(lwp) THEN
	461	WRITE(numout,*)
[9213]	462	WRITE(numout,*) ' ==>>> Assimilation background state valid at : ', zdate_bkg
	463	WRITE(numout,*)
[2128]	464	ENDIF
[5836]	465	!
[9213]	466	IF ( zdate_bkg /= ditdin_date ) &
[2128]	467	& CALL ctl_warn( ' Validity time of assimilation background state does', &
	468	& ' not agree with Direct Initialization time' )
[5836]	469	!
[2128]	470	IF ( ln_trainc ) THEN
	471	CALL iom_get( inum, jpdom_autoglo, 'tn', t_bkg )
	472	CALL iom_get( inum, jpdom_autoglo, 'sn', s_bkg )
	473	t_bkg(:,:,:) = t_bkg(:,:,:) * tmask(:,:,:)
	474	s_bkg(:,:,:) = s_bkg(:,:,:) * tmask(:,:,:)
	475	ENDIF
[5836]	476	!
[2128]	477	IF ( ln_dyninc ) THEN
	478	CALL iom_get( inum, jpdom_autoglo, 'un', u_bkg )
	479	CALL iom_get( inum, jpdom_autoglo, 'vn', v_bkg )
	480	u_bkg(:,:,:) = u_bkg(:,:,:) * umask(:,:,:)
	481	v_bkg(:,:,:) = v_bkg(:,:,:) * vmask(:,:,:)
	482	ENDIF
[5836]	483	!
[2128]	484	IF ( ln_sshinc ) THEN
	485	CALL iom_get( inum, jpdom_autoglo, 'sshn', ssh_bkg )
	486	ssh_bkg(:,:) = ssh_bkg(:,:) * tmask(:,:,1)
	487	ENDIF
[5836]	488	!
[2128]	489	CALL iom_close( inum )
[5836]	490	!
[2128]	491	ENDIF
[2392]	492	!
[9213]	493	IF(lwp) WRITE(numout,*) ' ==>>> Euler time step switch is ', neuler
	494	!
	495	IF( lk_asminc ) THEN !== data assimilation ==!
	496	IF( ln_bkgwri ) CALL asm_bkg_wri( nit000 - 1 ) ! Output background fields
	497	IF( ln_asmdin ) THEN ! Direct initialization
	498	IF( ln_trainc ) CALL tra_asm_inc( nit000 - 1 ) ! Tracers
	499	IF( ln_dyninc ) CALL dyn_asm_inc( nit000 - 1 ) ! Dynamics
	500	IF( ln_sshinc ) CALL ssh_asm_inc( nit000 - 1 ) ! SSH
	501	ENDIF
	502	ENDIF
	503	!
[2128]	504	END SUBROUTINE asm_inc_init
[9213]	505
	506
[2128]	507	SUBROUTINE tra_asm_inc( kt )
	508	!!----------------------------------------------------------------------
	509	!! * ROUTINE tra_asm_inc *
	510	!!
	511	!! ** Purpose : Apply the tracer (T and S) assimilation increments
	512	!!
	513	!! ** Method : Direct initialization or Incremental Analysis Updating
	514	!!
	515	!! ** Action :
	516	!!----------------------------------------------------------------------
[5836]	517	INTEGER, INTENT(IN) :: kt ! Current time step
[2392]	518	!
[5836]	519	INTEGER :: ji, jj, jk
	520	INTEGER :: it
[2128]	521	REAL(wp) :: zincwgt ! IAU weight for current time step
[3764]	522	REAL (wp), DIMENSION(jpi,jpj,jpk) :: fzptnz ! 3d freezing point values
[2392]	523	!!----------------------------------------------------------------------
[5836]	524	!
[3764]	525	! freezing point calculation taken from oc_fz_pt (but calculated for all depths)
	526	! used to prevent the applied increments taking the temperature below the local freezing point
[4990]	527	DO jk = 1, jpkm1
[6140]	528	CALL eos_fzp( tsn(:,:,jk,jp_sal), fzptnz(:,:,jk), gdept_n(:,:,jk) )
[4990]	529	END DO
[5836]	530	!
	531	! !--------------------------------------
	532	IF ( ln_asmiau ) THEN ! Incremental Analysis Updating
	533	! !--------------------------------------
	534	!
[2128]	535	IF ( ( kt >= nitiaustr_r ).AND.( kt <= nitiaufin_r ) ) THEN
[5836]	536	!
[2128]	537	it = kt - nit000 + 1
	538	zincwgt = wgtiau(it) / rdt ! IAU weight for the current time step
[5836]	539	!
[2128]	540	IF(lwp) THEN
	541	WRITE(numout,*)
[4990]	542	WRITE(numout,*) 'tra_asm_inc : Tracer IAU at time step = ', kt,' with IAU weight = ', wgtiau(it)
[2128]	543	WRITE(numout,*) '~~~~~~~~~~~~'
	544	ENDIF
[5836]	545	!
[2128]	546	! Update the tracer tendencies
	547	DO jk = 1, jpkm1
[3764]	548	IF (ln_temnofreeze) THEN
	549	! Do not apply negative increments if the temperature will fall below freezing
	550	WHERE(t_bkginc(:,:,jk) > 0.0_wp .OR. &
	551	& tsn(:,:,jk,jp_tem) + tsa(:,:,jk,jp_tem) + t_bkginc(:,:,jk) * wgtiau(it) > fzptnz(:,:,jk) )
	552	tsa(:,:,jk,jp_tem) = tsa(:,:,jk,jp_tem) + t_bkginc(:,:,jk) * zincwgt
	553	END WHERE
	554	ELSE
	555	tsa(:,:,jk,jp_tem) = tsa(:,:,jk,jp_tem) + t_bkginc(:,:,jk) * zincwgt
	556	ENDIF
	557	IF (ln_salfix) THEN
	558	! Do not apply negative increments if the salinity will fall below a specified
	559	! minimum value salfixmin
	560	WHERE(s_bkginc(:,:,jk) > 0.0_wp .OR. &
	561	& tsn(:,:,jk,jp_sal) + tsa(:,:,jk,jp_sal) + s_bkginc(:,:,jk) * wgtiau(it) > salfixmin )
	562	tsa(:,:,jk,jp_sal) = tsa(:,:,jk,jp_sal) + s_bkginc(:,:,jk) * zincwgt
	563	END WHERE
	564	ELSE
	565	tsa(:,:,jk,jp_sal) = tsa(:,:,jk,jp_sal) + s_bkginc(:,:,jk) * zincwgt
	566	ENDIF
[2128]	567	END DO
[5836]	568	!
[2128]	569	ENDIF
[5836]	570	!
[2128]	571	IF ( kt == nitiaufin_r + 1 ) THEN ! For bias crcn to work
	572	DEALLOCATE( t_bkginc )
	573	DEALLOCATE( s_bkginc )
	574	ENDIF
[5836]	575	! !--------------------------------------
	576	ELSEIF ( ln_asmdin ) THEN ! Direct Initialization
	577	! !--------------------------------------
	578	!
[2128]	579	IF ( kt == nitdin_r ) THEN
[5836]	580	!
[2128]	581	neuler = 0 ! Force Euler forward step
[5836]	582	!
[2128]	583	! Initialize the now fields with the background + increment
[3764]	584	IF (ln_temnofreeze) THEN
	585	! Do not apply negative increments if the temperature will fall below freezing
[4990]	586	WHERE( t_bkginc(:,:,:) > 0.0_wp .OR. tsn(:,:,:,jp_tem) + t_bkginc(:,:,:) > fzptnz(:,:,:) )
[3764]	587	tsn(:,:,:,jp_tem) = t_bkg(:,:,:) + t_bkginc(:,:,:)
	588	END WHERE
	589	ELSE
	590	tsn(:,:,:,jp_tem) = t_bkg(:,:,:) + t_bkginc(:,:,:)
	591	ENDIF
[2128]	592	IF (ln_salfix) THEN
[3764]	593	! Do not apply negative increments if the salinity will fall below a specified
	594	! minimum value salfixmin
[4990]	595	WHERE( s_bkginc(:,:,:) > 0.0_wp .OR. tsn(:,:,:,jp_sal) + s_bkginc(:,:,:) > salfixmin )
[3764]	596	tsn(:,:,:,jp_sal) = s_bkg(:,:,:) + s_bkginc(:,:,:)
	597	END WHERE
	598	ELSE
	599	tsn(:,:,:,jp_sal) = s_bkg(:,:,:) + s_bkginc(:,:,:)
[2128]	600	ENDIF
	601
[4990]	602	tsb(:,:,:,:) = tsn(:,:,:,:) ! Update before fields
[2128]	603
[4990]	604	CALL eos( tsb, rhd, rhop, gdept_0(:,:,:) ) ! Before potential and in situ densities
	605	!!gm fabien
	606	! CALL eos( tsb, rhd, rhop ) ! Before potential and in situ densities
	607	!!gm
	608
[6140]	609	IF( ln_zps .AND. .NOT. lk_c1d .AND. .NOT. ln_isfcav) &
	610	& CALL zps_hde ( kt, jpts, tsb, gtsu, gtsv, & ! Partial steps: before horizontal gradient
	611	& rhd, gru , grv ) ! of t, s, rd at the last ocean level
	612	IF( ln_zps .AND. .NOT. lk_c1d .AND. ln_isfcav) &
	613	& CALL zps_hde_isf( nit000, jpts, tsb, gtsu, gtsv, gtui, gtvi, & ! Partial steps for top cell (ISF)
	614	& rhd, gru , grv , grui, grvi ) ! of t, s, rd at the last ocean level
	615
[2128]	616	DEALLOCATE( t_bkginc )
	617	DEALLOCATE( s_bkginc )
	618	DEALLOCATE( t_bkg )
	619	DEALLOCATE( s_bkg )
	620	ENDIF
[2392]	621	!
[2128]	622	ENDIF
[3764]	623	! Perhaps the following call should be in step
[5836]	624	IF ( ln_seaiceinc ) CALL seaice_asm_inc ( kt ) ! apply sea ice concentration increment
[2392]	625	!
[2128]	626	END SUBROUTINE tra_asm_inc
	627
[2392]	628
[2128]	629	SUBROUTINE dyn_asm_inc( kt )
	630	!!----------------------------------------------------------------------
	631	!! * ROUTINE dyn_asm_inc *
	632	!!
	633	!! ** Purpose : Apply the dynamics (u and v) assimilation increments.
	634	!!
	635	!! ** Method : Direct initialization or Incremental Analysis Updating.
	636	!!
	637	!! ** Action :
	638	!!----------------------------------------------------------------------
	639	INTEGER, INTENT(IN) :: kt ! Current time step
[2392]	640	!
[2128]	641	INTEGER :: jk
	642	INTEGER :: it
	643	REAL(wp) :: zincwgt ! IAU weight for current time step
[2392]	644	!!----------------------------------------------------------------------
[5836]	645	!
	646	! !--------------------------------------------
	647	IF ( ln_asmiau ) THEN ! Incremental Analysis Updating
	648	! !--------------------------------------------
	649	!
[2128]	650	IF ( ( kt >= nitiaustr_r ).AND.( kt <= nitiaufin_r ) ) THEN
[5836]	651	!
[2128]	652	it = kt - nit000 + 1
	653	zincwgt = wgtiau(it) / rdt ! IAU weight for the current time step
[5836]	654	!
[2128]	655	IF(lwp) THEN
	656	WRITE(numout,*)
[5836]	657	WRITE(numout,*) 'dyn_asm_inc : Dynamics IAU at time step = ', kt,' with IAU weight = ', wgtiau(it)
[2128]	658	WRITE(numout,*) '~~~~~~~~~~~~'
	659	ENDIF
[5836]	660	!
[2128]	661	! Update the dynamic tendencies
	662	DO jk = 1, jpkm1
	663	ua(:,:,jk) = ua(:,:,jk) + u_bkginc(:,:,jk) * zincwgt
	664	va(:,:,jk) = va(:,:,jk) + v_bkginc(:,:,jk) * zincwgt
	665	END DO
[5836]	666	!
[2128]	667	IF ( kt == nitiaufin_r ) THEN
	668	DEALLOCATE( u_bkginc )
	669	DEALLOCATE( v_bkginc )
	670	ENDIF
[5836]	671	!
[2128]	672	ENDIF
[5836]	673	! !-----------------------------------------
	674	ELSEIF ( ln_asmdin ) THEN ! Direct Initialization
	675	! !-----------------------------------------
	676	!
[2128]	677	IF ( kt == nitdin_r ) THEN
[5836]	678	!
[2128]	679	neuler = 0 ! Force Euler forward step
[5836]	680	!
[2128]	681	! Initialize the now fields with the background + increment
	682	un(:,:,:) = u_bkg(:,:,:) + u_bkginc(:,:,:)
	683	vn(:,:,:) = v_bkg(:,:,:) + v_bkginc(:,:,:)
[5836]	684	!
[2128]	685	ub(:,:,:) = un(:,:,:) ! Update before fields
	686	vb(:,:,:) = vn(:,:,:)
[5836]	687	!
[2128]	688	DEALLOCATE( u_bkg )
	689	DEALLOCATE( v_bkg )
	690	DEALLOCATE( u_bkginc )
	691	DEALLOCATE( v_bkginc )
	692	ENDIF
[2392]	693	!
[2128]	694	ENDIF
[2392]	695	!
[2128]	696	END SUBROUTINE dyn_asm_inc
	697
[2392]	698
[2128]	699	SUBROUTINE ssh_asm_inc( kt )
	700	!!----------------------------------------------------------------------
	701	!! * ROUTINE ssh_asm_inc *
	702	!!
	703	!! ** Purpose : Apply the sea surface height assimilation increment.
	704	!!
	705	!! ** Method : Direct initialization or Incremental Analysis Updating.
	706	!!
	707	!! ** Action :
	708	!!----------------------------------------------------------------------
	709	INTEGER, INTENT(IN) :: kt ! Current time step
[2392]	710	!
[2128]	711	INTEGER :: it
[3764]	712	INTEGER :: jk
[2128]	713	REAL(wp) :: zincwgt ! IAU weight for current time step
[2392]	714	!!----------------------------------------------------------------------
[5836]	715	!
	716	! !-----------------------------------------
	717	IF ( ln_asmiau ) THEN ! Incremental Analysis Updating
	718	! !-----------------------------------------
	719	!
[2128]	720	IF ( ( kt >= nitiaustr_r ).AND.( kt <= nitiaufin_r ) ) THEN
[5836]	721	!
[2128]	722	it = kt - nit000 + 1
	723	zincwgt = wgtiau(it) / rdt ! IAU weight for the current time step
[5836]	724	!
[2128]	725	IF(lwp) THEN
	726	WRITE(numout,*)
	727	WRITE(numout,*) 'ssh_asm_inc : SSH IAU at time step = ', &
	728	& kt,' with IAU weight = ', wgtiau(it)
	729	WRITE(numout,*) '~~~~~~~~~~~~'
	730	ENDIF
[5836]	731	!
[2128]	732	! Save the tendency associated with the IAU weighted SSH increment
	733	! (applied in dynspg.*)
	734	#if defined key_asminc
	735	ssh_iau(:,:) = ssh_bkginc(:,:) * zincwgt
	736	#endif
	737	IF ( kt == nitiaufin_r ) THEN
	738	DEALLOCATE( ssh_bkginc )
	739	ENDIF
[5836]	740	!
[8552]	741	#if defined key_asminc
[8547]	742	ELSE IF( kt == nitiaufin_r+1 ) THEN
[8546]	743	!
	744	ssh_iau(:,:) = 0._wp
	745	!
[8552]	746	#endif
[2128]	747	ENDIF
[5836]	748	! !-----------------------------------------
	749	ELSEIF ( ln_asmdin ) THEN ! Direct Initialization
	750	! !-----------------------------------------
	751	!
[2128]	752	IF ( kt == nitdin_r ) THEN
[5836]	753	!
	754	neuler = 0 ! Force Euler forward step
	755	!
	756	sshn(:,:) = ssh_bkg(:,:) + ssh_bkginc(:,:) ! Initialize the now fields the background + increment
	757	!
	758	sshb(:,:) = sshn(:,:) ! Update before fields
[6140]	759	e3t_b(:,:,:) = e3t_n(:,:,:)
	760	!!gm why not e3u_b, e3v_b, gdept_b ????
[5836]	761	!
[2128]	762	DEALLOCATE( ssh_bkg )
	763	DEALLOCATE( ssh_bkginc )
[5836]	764	!
[2128]	765	ENDIF
[2392]	766	!
[2128]	767	ENDIF
[2392]	768	!
[2128]	769	END SUBROUTINE ssh_asm_inc
	770
[9213]	771
[9023]	772	SUBROUTINE ssh_asm_div( kt, phdivn )
	773	!!----------------------------------------------------------------------
	774	!! * ROUTINE ssh_asm_div *
	775	!!
	776	!! ** Purpose : ssh increment with z* is incorporated via a correction of the local divergence
	777	!! across all the water column
	778	!!
	779	!! ** Method :
	780	!! CAUTION : sshiau is positive (inflow) decreasing the
	781	!! divergence and expressed in m/s
	782	!!
	783	!! ** Action : phdivn decreased by the ssh increment
	784	!!----------------------------------------------------------------------
	785	INTEGER, INTENT(IN) :: kt ! ocean time-step index
	786	REAL(wp), DIMENSION(:,:,:), INTENT(inout) :: phdivn ! horizontal divergence
	787	!!
	788	INTEGER :: jk ! dummy loop index
	789	REAL(wp), DIMENSION(:,:) , POINTER :: ztim ! local array
	790	!!----------------------------------------------------------------------
	791	!
	792	#if defined key_asminc
	793	CALL ssh_asm_inc( kt ) !== (calculate increments)
	794	!
	795	IF( ln_linssh ) THEN
	796	phdivn(:,:,1) = phdivn(:,:,1) - ssh_iau(:,:) / e3t_n(:,:,1) * tmask(:,:,1)
	797	ELSE
[9044]	798	ALLOCATE( ztim(jpi,jpj) )
[9023]	799	ztim(:,:) = ssh_iau(:,:) / ( ht_n(:,:) + 1.0 - ssmask(:,:) )
	800	DO jk = 1, jpkm1
	801	phdivn(:,:,jk) = phdivn(:,:,jk) - ztim(:,:) * tmask(:,:,jk)
	802	END DO
	803	!
[9044]	804	DEALLOCATE(ztim)
[9023]	805	ENDIF
	806	#endif
	807	!
	808	END SUBROUTINE ssh_asm_div
[3785]	809
[9213]	810
[3764]	811	SUBROUTINE seaice_asm_inc( kt, kindic )
	812	!!----------------------------------------------------------------------
	813	!! * ROUTINE seaice_asm_inc *
	814	!!
	815	!! ** Purpose : Apply the sea ice assimilation increment.
	816	!!
	817	!! ** Method : Direct initialization or Incremental Analysis Updating.
	818	!!
	819	!! ** Action :
	820	!!
	821	!!----------------------------------------------------------------------
[5836]	822	INTEGER, INTENT(in) :: kt ! Current time step
[3785]	823	INTEGER, INTENT(in), OPTIONAL :: kindic ! flag for disabling the deallocation
	824	!
	825	INTEGER :: it
	826	REAL(wp) :: zincwgt ! IAU weight for current time step
[9019]	827	#if defined key_lim3
[3785]	828	REAL(wp), DIMENSION(jpi,jpj) :: zofrld, zohicif, zseaicendg, zhicifinc ! LIM
	829	REAL(wp) :: zhicifmin = 0.5_wp ! ice minimum depth in metres
[3764]	830	#endif
[3785]	831	!!----------------------------------------------------------------------
[5836]	832	!
	833	! !-----------------------------------------
	834	IF ( ln_asmiau ) THEN ! Incremental Analysis Updating
	835	! !-----------------------------------------
	836	!
[3764]	837	IF ( ( kt >= nitiaustr_r ).AND.( kt <= nitiaufin_r ) ) THEN
[5836]	838	!
[3764]	839	it = kt - nit000 + 1
	840	zincwgt = wgtiau(it) ! IAU weight for the current time step
	841	! note this is not a tendency so should not be divided by rdt (as with the tracer and other increments)
[5836]	842	!
[3764]	843	IF(lwp) THEN
	844	WRITE(numout,*)
[5836]	845	WRITE(numout,*) 'seaice_asm_inc : sea ice conc IAU at time step = ', kt,' with IAU weight = ', wgtiau(it)
[3764]	846	WRITE(numout,*) '~~~~~~~~~~~~'
	847	ENDIF
[5836]	848	!
[9019]	849	! Sea-ice : LIM-3 case
[5836]	850	!
[9019]	851	#if defined key_lim3
	852	zofrld (:,:) = 1._wp - at_i(:,:)
	853	zohicif(:,:) = hm_i(:,:)
[3785]	854	!
[9019]	855	at_i (:,:) = 1. - MIN( MAX( 1.-at_i (:,:) - seaice_bkginc(:,:) * zincwgt, 0.0_wp), 1.0_wp)
	856	at_i_b(:,:) = 1. - MIN( MAX( 1.-at_i_b(:,:) - seaice_bkginc(:,:) * zincwgt, 0.0_wp), 1.0_wp)
	857	fr_i(:,:) = at_i(:,:) ! adjust ice fraction
[3785]	858	!
[9019]	859	zseaicendg(:,:) = zofrld(:,:) - (1. - at_i(:,:)) ! find out actual sea ice nudge applied
[3785]	860	!
[3764]	861	! Nudge sea ice depth to bring it up to a required minimum depth
[9019]	862	WHERE( zseaicendg(:,:) > 0.0_wp .AND. hm_i(:,:) < zhicifmin )
	863	zhicifinc(:,:) = (zhicifmin - hm_i(:,:)) * zincwgt
[3764]	864	ELSEWHERE
	865	zhicifinc(:,:) = 0.0_wp
	866	END WHERE
[3785]	867	!
	868	! nudge ice depth
[9019]	869	hm_i (:,:) = hm_i (:,:) + zhicifinc(:,:)
[3785]	870	!
	871	! seaice salinity balancing (to add)
[3764]	872	#endif
[9213]	873	!
[4245]	874	#if defined key_cice && defined key_asminc
[3785]	875	! Sea-ice : CICE case. Pass ice increment tendency into CICE
[3764]	876	ndaice_da(:,:) = seaice_bkginc(:,:) * zincwgt / rdt
	877	#endif
[9213]	878	!
[3764]	879	IF ( kt == nitiaufin_r ) THEN
	880	DEALLOCATE( seaice_bkginc )
	881	ENDIF
[9213]	882	!
[3764]	883	ELSE
[9213]	884	!
[4245]	885	#if defined key_cice && defined key_asminc
[5836]	886	ndaice_da(:,:) = 0._wp ! Sea-ice : CICE case. Zero ice increment tendency into CICE
[3764]	887	#endif
[9213]	888	!
[3764]	889	ENDIF
[5836]	890	! !-----------------------------------------
	891	ELSEIF ( ln_asmdin ) THEN ! Direct Initialization
	892	! !-----------------------------------------
	893	!
[3764]	894	IF ( kt == nitdin_r ) THEN
[5836]	895	!
[3764]	896	neuler = 0 ! Force Euler forward step
[5836]	897	!
[9019]	898	! Sea-ice : LIM-3 case
[5836]	899	!
[9019]	900	#if defined key_lim3
	901	zofrld (:,:) = 1._wp - at_i(:,:)
	902	zohicif(:,:) = hm_i(:,:)
[3785]	903	!
[3764]	904	! Initialize the now fields the background + increment
[9019]	905	at_i(:,:) = 1. - MIN( MAX( 1.-at_i(:,:) - seaice_bkginc(:,:), 0.0_wp), 1.0_wp)
	906	at_i_b(:,:) = at_i(:,:)
	907	fr_i(:,:) = at_i(:,:) ! adjust ice fraction
[3785]	908	!
[9019]	909	zseaicendg(:,:) = zofrld(:,:) - (1. - at_i(:,:)) ! find out actual sea ice nudge applied
	910	!
[3764]	911	! Nudge sea ice depth to bring it up to a required minimum depth
[9019]	912	WHERE( zseaicendg(:,:) > 0.0_wp .AND. hm_i(:,:) < zhicifmin )
	913	zhicifinc(:,:) = (zhicifmin - hm_i(:,:)) * zincwgt
[3764]	914	ELSEWHERE
[9019]	915	zhicifinc(:,:) = 0.0_wp
[3764]	916	END WHERE
[3785]	917	!
	918	! nudge ice depth
[9019]	919	hm_i (:,:) = hm_i (:,:) + zhicifinc(:,:)
[3785]	920	!
	921	! seaice salinity balancing (to add)
[3764]	922	#endif
[5836]	923	!
[4245]	924	#if defined key_cice && defined key_asminc
	925	! Sea-ice : CICE case. Pass ice increment tendency into CICE
[3764]	926	ndaice_da(:,:) = seaice_bkginc(:,:) / rdt
	927	#endif
[5836]	928	IF ( .NOT. PRESENT(kindic) ) THEN
	929	DEALLOCATE( seaice_bkginc )
	930	END IF
	931	!
[3764]	932	ELSE
[5836]	933	!
	934	#if defined key_cice && defined key_asminc
	935	ndaice_da(:,:) = 0._wp ! Sea-ice : CICE case. Zero ice increment tendency into CICE
[3764]	936	#endif
[5836]	937	!
[3764]	938	ENDIF
	939
[9019]	940	!#if defined defined key_lim3 \|\| defined key_cice
[3764]	941	!
	942	! IF (ln_seaicebal ) THEN
	943	! !! balancing salinity increments
	944	! !! simple case from limflx.F90 (doesn't include a mass flux)
	945	! !! assumption is that as ice concentration is reduced or increased
	946	! !! the snow and ice depths remain constant
	947	! !! note that snow is being created where ice concentration is being increased
	948	! !! - could be more sophisticated and
	949	! !! not do this (but would need to alter h_snow)
	950	!
	951	! usave(:,:,:)=sb(:,:,:) ! use array as a temporary store
	952	!
	953	! DO jj = 1, jpj
	954	! DO ji = 1, jpi
	955	! ! calculate change in ice and snow mass per unit area
	956	! ! positive values imply adding salt to the ocean (results from ice formation)
	957	! ! fwf : ice formation and melting
	958	!
	959	! zfons = ( -nfresh_da(ji,jj)soce + nfsalt_da(ji,jj) )rdt
	960	!
	961	! ! change salinity down to mixed layer depth
	962	! mld=hmld_kara(ji,jj)
	963	!
	964	! ! prevent small mld
	965	! ! less than 10m can cause salinity instability
	966	! IF (mld < 10) mld=10
	967	!
	968	! ! set to bottom of a level
	969	! DO jk = jpk-1, 2, -1
	970	! IF ((mld > gdepw(ji,jj,jk)) .and. (mld < gdepw(ji,jj,jk+1))) THEN
	971	! mld=gdepw(ji,jj,jk+1)
	972	! jkmax=jk
	973	! ENDIF
	974	! ENDDO
	975	!
	976	! ! avoid applying salinity balancing in shallow water or on land
	977	! !
	978	!
	979	! ! dsal_ocn (psu kg m^-2) / (kg m^-3 * m)
	980	!
	981	! dsal_ocn=0.0_wp
	982	! sal_thresh=5.0_wp ! minimum salinity threshold for salinity balancing
	983	!
	984	! if (tmask(ji,jj,1) > 0 .AND. tmask(ji,jj,jkmax) > 0 ) &
	985	! dsal_ocn = zfons / (rhop(ji,jj,1) * mld)
	986	!
	987	! ! put increments in for levels in the mixed layer
	988	! ! but prevent salinity below a threshold value
	989	!
	990	! DO jk = 1, jkmax
	991	!
	992	! IF (dsal_ocn > 0.0_wp .or. sb(ji,jj,jk)+dsal_ocn > sal_thresh) THEN
	993	! sb(ji,jj,jk) = sb(ji,jj,jk) + dsal_ocn
	994	! sn(ji,jj,jk) = sn(ji,jj,jk) + dsal_ocn
	995	! ENDIF
	996	!
	997	! ENDDO
	998	!
	999	! ! ! salt exchanges at the ice/ocean interface
	1000	! ! zpmess = zfons / rdt_ice ! rdt_ice is ice timestep
	1001	! !
	1002	! !! Adjust fsalt. A +ve fsalt means adding salt to ocean
	1003	! !! fsalt(ji,jj) = fsalt(ji,jj) + zpmess ! adjust fsalt
	1004	! !!
	1005	! !! emps(ji,jj) = emps(ji,jj) + zpmess ! or adjust emps (see icestp1d)
	1006	! !! ! E-P (kg m-2 s-2)
	1007	! ! emp(ji,jj) = emp(ji,jj) + zpmess ! E-P (kg m-2 s-2)
	1008	! ENDDO !ji
	1009	! ENDDO !jj!
	1010	!
	1011	! ENDIF !ln_seaicebal
	1012	!
	1013	!#endif
[5836]	1014	!
[3764]	1015	ENDIF
[5836]	1016	!
[3764]	1017	END SUBROUTINE seaice_asm_inc
[3785]	1018
[2392]	1019	!!======================================================================
[2128]	1020	END MODULE asminc

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