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asminc.F90

Last change on this file was 15183, checked in by kingr, 3 years ago
Adding changes required to write out time-averaged assimilation background. Required moving call to asm_bkg_wri from asminc.F90 to nemogcm.F90 to avoid circular USE statements.
File size: 49.1 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
	33	USE c1d ! 1D initialization
	34	USE sbc_oce ! Surface boundary condition variables.
	35	USE diaobs , ONLY : calc_date ! Compute the calendar date on a given step
[9570]	36	#if defined key_si3
[9019]	37	USE ice , ONLY : hm_i, at_i, at_i_b
[3764]	38	#endif
[9019]	39	!
	40	USE in_out_manager ! I/O manager
	41	USE iom ! Library to read input files
	42	USE lib_mpp ! MPP library
[2128]	43
	44	IMPLICIT NONE
	45	PRIVATE
[2392]	46
	47	PUBLIC asm_inc_init !: Initialize the increment arrays and IAU weights
	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
[9023]	51	PUBLIC ssh_asm_div !: Apply the SSH divergence
[3764]	52	PUBLIC seaice_asm_inc !: Apply the seaice increment
[2128]	53
	54	#if defined key_asminc
[2392]	55	LOGICAL, PUBLIC, PARAMETER :: lk_asminc = .TRUE. !: Logical switch for assimilation increment interface
[2128]	56	#else
[2392]	57	LOGICAL, PUBLIC, PARAMETER :: lk_asminc = .FALSE. !: No assimilation increments
[2128]	58	#endif
[5836]	59	LOGICAL, PUBLIC :: ln_bkgwri !: No output of the background state fields
[15183]	60	LOGICAL, PUBLIC :: ln_avgbkg !: No output of the mean background state fields
[5836]	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
[15183]	84	INTEGER , PUBLIC :: nitavgbkg !: Number of timesteps to average assim bkg [0,nitavgbkg]
[2392]	85	!
	86	INTEGER , PUBLIC :: niaufn !: Type of IAU weighing function: = 0 Constant weighting
	87	! !: = 1 Linear hat-like, centred in middle of IAU interval
	88	REAL(wp), PUBLIC :: salfixmin !: Ensure that the salinity is larger than this value if (ln_salfix)
[2128]	89
[2392]	90	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: ssh_bkg, ssh_bkginc ! Background sea surface height and its increment
[3764]	91	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: seaice_bkginc ! Increment to the background sea ice conc
[8030]	92	#if defined key_cice && defined key_asminc
	93	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: ndaice_da ! ice increment tendency into CICE
	94	#endif
[2128]	95
[3294]	96	!! * Substitutions
	97	# include "vectopt_loop_substitute.h90"
[2287]	98	!!----------------------------------------------------------------------
[9598]	99	!! NEMO/OCE 4.0 , NEMO Consortium (2018)
[2287]	100	!! $Id$
[10068]	101	!! Software governed by the CeCILL license (see ./LICENSE)
[2287]	102	!!----------------------------------------------------------------------
[2128]	103	CONTAINS
	104
	105	SUBROUTINE asm_inc_init
	106	!!----------------------------------------------------------------------
	107	!! * ROUTINE asm_inc_init *
	108	!!
	109	!! ** Purpose : Initialize the assimilation increment and IAU weights.
	110	!!
	111	!! ** Method : Initialize the assimilation increment and IAU weights.
	112	!!
	113	!! ** Action :
	114	!!----------------------------------------------------------------------
[4990]	115	INTEGER :: ji, jj, jk, jt ! dummy loop indices
	116	INTEGER :: imid, inum ! local integers
	117	INTEGER :: ios ! Local integer output status for namelist read
[2128]	118	INTEGER :: iiauper ! Number of time steps in the IAU period
	119	INTEGER :: icycper ! Number of time steps in the cycle
[6140]	120	REAL(KIND=dp) :: ditend_date ! Date YYYYMMDD.HHMMSS of final time step
	121	REAL(KIND=dp) :: ditbkg_date ! Date YYYYMMDD.HHMMSS of background time step for Jb term
	122	REAL(KIND=dp) :: ditdin_date ! Date YYYYMMDD.HHMMSS of background time step for DI
	123	REAL(KIND=dp) :: ditiaustr_date ! Date YYYYMMDD.HHMMSS of IAU interval start time step
	124	REAL(KIND=dp) :: ditiaufin_date ! Date YYYYMMDD.HHMMSS of IAU interval final time step
[15183]	125	REAL(KIND=dp) :: ditavgbkg_date ! Date YYYYMMDD.HHMMSS of end of assim bkg averaging period
[6140]	126
[2128]	127	REAL(wp) :: znorm ! Normalization factor for IAU weights
[4990]	128	REAL(wp) :: ztotwgt ! Value of time-integrated IAU weights (should be equal to one)
[2128]	129	REAL(wp) :: z_inc_dateb ! Start date of interval on which increment is valid
	130	REAL(wp) :: z_inc_datef ! End date of interval on which increment is valid
	131	REAL(wp) :: zdate_bkg ! Date in background state file for DI
	132	REAL(wp) :: zdate_inc ! Time axis in increments file
[4990]	133	!
[9019]	134	REAL(wp), ALLOCATABLE, DIMENSION(:,:) :: zhdiv ! 2D workspace
[2392]	135	!!
[15183]	136	NAMELIST/nam_asminc/ ln_bkgwri, ln_avgbkg, &
[2392]	137	& ln_trainc, ln_dyninc, ln_sshinc, &
	138	& ln_asmdin, ln_asmiau, &
	139	& nitbkg, nitdin, nitiaustr, nitiaufin, niaufn, &
[15183]	140	& ln_salfix, salfixmin, nn_divdmp, nitavgbkg
[2392]	141	!!----------------------------------------------------------------------
[2128]	142
	143	!-----------------------------------------------------------------------
	144	! Read Namelist nam_asminc : assimilation increment interface
	145	!-----------------------------------------------------------------------
[15183]	146	! Set default values
	147	ln_bkgwri = .FALSE.
	148	ln_avgbkg = .FALSE.
	149	ln_trainc = .FALSE.
	150	ln_dyninc = .FALSE.
	151	ln_sshinc = .FALSE.
	152	ln_asmdin = .FALSE.
	153	ln_asmiau = .TRUE.
	154	ln_salfix = .FALSE.
	155	ln_seaiceinc = .FALSE.
[3764]	156	ln_temnofreeze = .FALSE.
[15183]	157	nitbkg = 0
	158	nitdin = 0
	159	nitiaustr = 1
	160	nitiaufin = 150
	161	niaufn = 0
	162	salfixmin = -9999
	163	nitavgbkg = 1
[2128]	164
[4147]	165	REWIND( numnam_ref ) ! Namelist nam_asminc in reference namelist : Assimilation increment
	166	READ ( numnam_ref, nam_asminc, IOSTAT = ios, ERR = 901)
[11536]	167	901 IF( ios /= 0 ) CALL ctl_nam ( ios , 'nam_asminc in reference namelist' )
[4147]	168	REWIND( numnam_cfg ) ! Namelist nam_asminc in configuration namelist : Assimilation increment
	169	READ ( numnam_cfg, nam_asminc, IOSTAT = ios, ERR = 902 )
[11536]	170	902 IF( ios > 0 ) CALL ctl_nam ( ios , 'nam_asminc in configuration namelist' )
[4624]	171	IF(lwm) WRITE ( numond, nam_asminc )
[4147]	172
[2128]	173	! Control print
	174	IF(lwp) THEN
	175	WRITE(numout,*)
	176	WRITE(numout,*) 'asm_inc_init : Assimilation increment initialization :'
	177	WRITE(numout,*) '~~~~~~~~~~~~'
[2392]	178	WRITE(numout,*) ' Namelist namasm : set assimilation increment parameters'
	179	WRITE(numout,*) ' Logical switch for writing out background state ln_bkgwri = ', ln_bkgwri
[15183]	180	WRITE(numout,*) ' Logical switch for writing mean background state ln_avgbkg = ', ln_avgbkg
[2392]	181	WRITE(numout,*) ' Logical switch for applying tracer increments ln_trainc = ', ln_trainc
	182	WRITE(numout,*) ' Logical switch for applying velocity increments ln_dyninc = ', ln_dyninc
	183	WRITE(numout,*) ' Logical switch for applying SSH increments ln_sshinc = ', ln_sshinc
	184	WRITE(numout,*) ' Logical switch for Direct Initialization (DI) ln_asmdin = ', ln_asmdin
[3764]	185	WRITE(numout,*) ' Logical switch for applying sea ice increments ln_seaiceinc = ', ln_seaiceinc
[2392]	186	WRITE(numout,*) ' Logical switch for Incremental Analysis Updating (IAU) ln_asmiau = ', ln_asmiau
	187	WRITE(numout,*) ' Timestep of background in [0,nitend-nit000-1] nitbkg = ', nitbkg
	188	WRITE(numout,*) ' Timestep of background for DI in [0,nitend-nit000-1] nitdin = ', nitdin
	189	WRITE(numout,*) ' Timestep of start of IAU interval in [0,nitend-nit000-1] nitiaustr = ', nitiaustr
	190	WRITE(numout,*) ' Timestep of end of IAU interval in [0,nitend-nit000-1] nitiaufin = ', nitiaufin
[15183]	191	WRITE(numout,*) ' Number of timesteps to average assim bkg [0,nitavgbkg] nitavgbkg = ', nitavgbkg
[2392]	192	WRITE(numout,*) ' Type of IAU weighting function niaufn = ', niaufn
	193	WRITE(numout,*) ' Logical switch for ensuring that the sa > salfixmin ln_salfix = ', ln_salfix
	194	WRITE(numout,*) ' Minimum salinity after applying the increments salfixmin = ', salfixmin
[2128]	195	ENDIF
	196
[9019]	197	nitbkg_r = nitbkg + nit000 - 1 ! Background time referenced to nit000
	198	nitdin_r = nitdin + nit000 - 1 ! Background time for DI referenced to nit000
	199	nitiaustr_r = nitiaustr + nit000 - 1 ! Start of IAU interval referenced to nit000
	200	nitiaufin_r = nitiaufin + nit000 - 1 ! End of IAU interval referenced to nit000
[15183]	201	nitavgbkg_r = nitavgbkg + nit000 - 1 ! Averaging period referenced to nit000
[2128]	202
[9019]	203	iiauper = nitiaufin_r - nitiaustr_r + 1 ! IAU interval length
	204	icycper = nitend - nit000 + 1 ! Cycle interval length
[2128]	205
[9019]	206	CALL calc_date( nitend , ditend_date ) ! Date of final time step
	207	CALL calc_date( nitbkg_r , ditbkg_date ) ! Background time for Jb referenced to ndate0
	208	CALL calc_date( nitdin_r , ditdin_date ) ! Background time for DI referenced to ndate0
	209	CALL calc_date( nitiaustr_r, ditiaustr_date ) ! IAU start time referenced to ndate0
	210	CALL calc_date( nitiaufin_r, ditiaufin_date ) ! IAU end time referenced to ndate0
[15183]	211	CALL calc_date( nitavgbkg_r, ditavgbkg_date ) ! End of assim bkg averaging period referenced to ndate0
[6140]	212
[2128]	213	IF(lwp) THEN
	214	WRITE(numout,*)
	215	WRITE(numout,*) ' Time steps referenced to current cycle:'
	216	WRITE(numout,*) ' iitrst = ', nit000 - 1
	217	WRITE(numout,*) ' nit000 = ', nit000
	218	WRITE(numout,*) ' nitend = ', nitend
	219	WRITE(numout,*) ' nitbkg_r = ', nitbkg_r
	220	WRITE(numout,*) ' nitdin_r = ', nitdin_r
	221	WRITE(numout,*) ' nitiaustr_r = ', nitiaustr_r
	222	WRITE(numout,*) ' nitiaufin_r = ', nitiaufin_r
[15183]	223	WRITE(numout,*) ' nitavgbkg_r = ', nitavgbkg_r
[2128]	224	WRITE(numout,*)
	225	WRITE(numout,*) ' Dates referenced to current cycle:'
	226	WRITE(numout,*) ' ndastp = ', ndastp
	227	WRITE(numout,*) ' ndate0 = ', ndate0
[6140]	228	WRITE(numout,*) ' nn_time0 = ', nn_time0
	229	WRITE(numout,*) ' ditend_date = ', ditend_date
	230	WRITE(numout,*) ' ditbkg_date = ', ditbkg_date
	231	WRITE(numout,*) ' ditdin_date = ', ditdin_date
	232	WRITE(numout,*) ' ditiaustr_date = ', ditiaustr_date
	233	WRITE(numout,*) ' ditiaufin_date = ', ditiaufin_date
[15183]	234	WRITE(numout,*) ' ditavgbkg_date = ', ditavgbkg_date
[2128]	235	ENDIF
	236
	237
	238	IF ( ( ln_asmdin ).AND.( ln_asmiau ) ) &
	239	& CALL ctl_stop( ' ln_asmdin and ln_asmiau :', &
	240	& ' Choose Direct Initialization OR Incremental Analysis Updating')
	241
	242	IF ( ( ( .NOT. ln_asmdin ).AND.( .NOT. ln_asmiau ) ) &
[3764]	243	.AND.( ( ln_trainc ).OR.( ln_dyninc ).OR.( ln_sshinc ) .OR. ( ln_seaiceinc) )) &
	244	& CALL ctl_stop( ' One or more of ln_trainc, ln_dyninc, ln_sshinc and ln_seaiceinc is set to .true.', &
[2128]	245	& ' but ln_asmdin and ln_asmiau are both set to .false. :', &
	246	& ' Inconsistent options')
	247
	248	IF ( ( niaufn /= 0 ).AND.( niaufn /= 1 ) ) &
	249	& CALL ctl_stop( ' niaufn /= 0 or niaufn /=1 :', &
	250	& ' Type IAU weighting function is invalid')
	251
[3764]	252	IF ( ( .NOT. ln_trainc ).AND.( .NOT. ln_dyninc ).AND.( .NOT. ln_sshinc ).AND.( .NOT. ln_seaiceinc ) &
[2128]	253	& ) &
[3764]	254	& CALL ctl_warn( ' ln_trainc, ln_dyninc, ln_sshinc and ln_seaiceinc are set to .false. :', &
[2128]	255	& ' The assimilation increments are not applied')
	256
	257	IF ( ( ln_asmiau ).AND.( nitiaustr == nitiaufin ) ) &
	258	& CALL ctl_stop( ' nitiaustr = nitiaufin :', &
	259	& ' IAU interval is of zero length')
	260
	261	IF ( ( ln_asmiau ).AND.( ( nitiaustr_r < nit000 ).OR.( nitiaufin_r > nitend ) ) ) &
	262	& CALL ctl_stop( ' nitiaustr or nitiaufin :', &
	263	& ' IAU starting or final time step is outside the cycle interval', &
	264	& ' Valid range nit000 to nitend')
	265
	266	IF ( ( nitbkg_r < nit000 - 1 ).OR.( nitbkg_r > nitend ) ) &
	267	& CALL ctl_stop( ' nitbkg :', &
	268	& ' Background time step is outside the cycle interval')
	269
	270	IF ( ( nitdin_r < nit000 - 1 ).OR.( nitdin_r > nitend ) ) &
	271	& CALL ctl_stop( ' nitdin :', &
	272	& ' Background time step for Direct Initialization is outside', &
	273	& ' the cycle interval')
	274
[15183]	275	IF ( nitavgbkg_r > nitend ) &
	276	& CALL ctl_stop( ' nitavgbkg_r :', &
	277	& ' Assim bkg averaging period is outside', &
	278	& ' the cycle interval')
	279
[2128]	280	IF ( nstop > 0 ) RETURN ! if there are any errors then go no further
	281
	282	!--------------------------------------------------------------------
	283	! Initialize the Incremental Analysis Updating weighting function
	284	!--------------------------------------------------------------------
	285
[9213]	286	IF( ln_asmiau ) THEN
	287	!
[2128]	288	ALLOCATE( wgtiau( icycper ) )
[9213]	289	!
[9019]	290	wgtiau(:) = 0._wp
[9213]	291	!
	292	! !---------------------------------------------------------
	293	IF( niaufn == 0 ) THEN ! Constant IAU forcing
	294	! !---------------------------------------------------------
[2128]	295	DO jt = 1, iiauper
	296	wgtiau(jt+nitiaustr-1) = 1.0 / REAL( iiauper )
	297	END DO
[9213]	298	! !---------------------------------------------------------
	299	ELSEIF ( niaufn == 1 ) THEN ! Linear hat-like, centred in middle of IAU interval
	300	! !---------------------------------------------------------
[2128]	301	! Compute the normalization factor
[9213]	302	znorm = 0._wp
	303	IF( MOD( iiauper, 2 ) == 0 ) THEN ! Even number of time steps in IAU interval
[2128]	304	imid = iiauper / 2
	305	DO jt = 1, imid
	306	znorm = znorm + REAL( jt )
	307	END DO
	308	znorm = 2.0 * znorm
[9213]	309	ELSE ! Odd number of time steps in IAU interval
[2128]	310	imid = ( iiauper + 1 ) / 2
	311	DO jt = 1, imid - 1
	312	znorm = znorm + REAL( jt )
	313	END DO
	314	znorm = 2.0 * znorm + REAL( imid )
	315	ENDIF
	316	znorm = 1.0 / znorm
[9213]	317	!
[2128]	318	DO jt = 1, imid - 1
	319	wgtiau(jt+nitiaustr-1) = REAL( jt ) * znorm
	320	END DO
	321	DO jt = imid, iiauper
	322	wgtiau(jt+nitiaustr-1) = REAL( iiauper - jt + 1 ) * znorm
	323	END DO
[9213]	324	!
[2128]	325	ENDIF
	326
	327	! Test that the integral of the weights over the weighting interval equals 1
	328	IF(lwp) THEN
	329	WRITE(numout,*)
	330	WRITE(numout,*) 'asm_inc_init : IAU weights'
	331	WRITE(numout,*) '~~~~~~~~~~~~'
	332	WRITE(numout,*) ' time step IAU weight'
	333	WRITE(numout,*) ' ========= ====================='
	334	ztotwgt = 0.0
	335	DO jt = 1, icycper
	336	ztotwgt = ztotwgt + wgtiau(jt)
	337	WRITE(numout,*) ' ', jt, ' ', wgtiau(jt)
	338	END DO
	339	WRITE(numout,*) ' ==================================='
	340	WRITE(numout,*) ' Time-integrated weight = ', ztotwgt
	341	WRITE(numout,*) ' ==================================='
	342	ENDIF
	343
	344	ENDIF
	345
	346	!--------------------------------------------------------------------
	347	! Allocate and initialize the increment arrays
	348	!--------------------------------------------------------------------
	349
[9213]	350	ALLOCATE( t_bkginc (jpi,jpj,jpk) ) ; t_bkginc (:,:,:) = 0._wp
	351	ALLOCATE( s_bkginc (jpi,jpj,jpk) ) ; s_bkginc (:,:,:) = 0._wp
	352	ALLOCATE( u_bkginc (jpi,jpj,jpk) ) ; u_bkginc (:,:,:) = 0._wp
	353	ALLOCATE( v_bkginc (jpi,jpj,jpk) ) ; v_bkginc (:,:,:) = 0._wp
	354	ALLOCATE( ssh_bkginc (jpi,jpj) ) ; ssh_bkginc (:,:) = 0._wp
	355	ALLOCATE( seaice_bkginc(jpi,jpj) ) ; seaice_bkginc(:,:) = 0._wp
[2128]	356	#if defined key_asminc
[9213]	357	ALLOCATE( ssh_iau (jpi,jpj) ) ; ssh_iau (:,:) = 0._wp
[2128]	358	#endif
[8030]	359	#if defined key_cice && defined key_asminc
[9213]	360	ALLOCATE( ndaice_da (jpi,jpj) ) ; ndaice_da (:,:) = 0._wp
[8030]	361	#endif
[9213]	362	!
	363	IF ( ln_trainc .OR. ln_dyninc .OR. & !--------------------------------------
	364	& ln_sshinc .OR. ln_seaiceinc ) THEN ! Read the increments from file
	365	! !--------------------------------------
[2128]	366	CALL iom_open( c_asminc, inum )
[9213]	367	!
	368	CALL iom_get( inum, 'time' , zdate_inc )
[2128]	369	CALL iom_get( inum, 'z_inc_dateb', z_inc_dateb )
	370	CALL iom_get( inum, 'z_inc_datef', z_inc_datef )
	371	z_inc_dateb = zdate_inc
	372	z_inc_datef = zdate_inc
[9213]	373	!
[2128]	374	IF(lwp) THEN
	375	WRITE(numout,*)
[9213]	376	WRITE(numout,*) 'asm_inc_init : Assimilation increments valid between dates ', z_inc_dateb,' and ', z_inc_datef
[2128]	377	WRITE(numout,*) '~~~~~~~~~~~~'
	378	ENDIF
[9213]	379	!
	380	IF ( ( z_inc_dateb < ndastp + nn_time0*0.0001_wp ) .OR. &
	381	& ( z_inc_datef > ditend_date ) ) &
	382	& CALL ctl_warn( ' Validity time of assimilation increments is ', &
	383	& ' outside the assimilation interval' )
[2128]	384
[6140]	385	IF ( ( ln_asmdin ).AND.( zdate_inc /= ditdin_date ) ) &
[2128]	386	& CALL ctl_warn( ' Validity time of assimilation increments does ', &
	387	& ' not agree with Direct Initialization time' )
	388
	389	IF ( ln_trainc ) THEN
	390	CALL iom_get( inum, jpdom_autoglo, 'bckint', t_bkginc, 1 )
	391	CALL iom_get( inum, jpdom_autoglo, 'bckins', s_bkginc, 1 )
	392	! Apply the masks
	393	t_bkginc(:,:,:) = t_bkginc(:,:,:) * tmask(:,:,:)
	394	s_bkginc(:,:,:) = s_bkginc(:,:,:) * tmask(:,:,:)
	395	! Set missing increments to 0.0 rather than 1e+20
	396	! to allow for differences in masks
	397	WHERE( ABS( t_bkginc(:,:,:) ) > 1.0e+10 ) t_bkginc(:,:,:) = 0.0
	398	WHERE( ABS( s_bkginc(:,:,:) ) > 1.0e+10 ) s_bkginc(:,:,:) = 0.0
	399	ENDIF
	400
	401	IF ( ln_dyninc ) THEN
	402	CALL iom_get( inum, jpdom_autoglo, 'bckinu', u_bkginc, 1 )
	403	CALL iom_get( inum, jpdom_autoglo, 'bckinv', v_bkginc, 1 )
	404	! Apply the masks
	405	u_bkginc(:,:,:) = u_bkginc(:,:,:) * umask(:,:,:)
	406	v_bkginc(:,:,:) = v_bkginc(:,:,:) * vmask(:,:,:)
	407	! Set missing increments to 0.0 rather than 1e+20
	408	! to allow for differences in masks
	409	WHERE( ABS( u_bkginc(:,:,:) ) > 1.0e+10 ) u_bkginc(:,:,:) = 0.0
	410	WHERE( ABS( v_bkginc(:,:,:) ) > 1.0e+10 ) v_bkginc(:,:,:) = 0.0
	411	ENDIF
	412
	413	IF ( ln_sshinc ) THEN
	414	CALL iom_get( inum, jpdom_autoglo, 'bckineta', ssh_bkginc, 1 )
	415	! Apply the masks
	416	ssh_bkginc(:,:) = ssh_bkginc(:,:) * tmask(:,:,1)
	417	! Set missing increments to 0.0 rather than 1e+20
	418	! to allow for differences in masks
	419	WHERE( ABS( ssh_bkginc(:,:) ) > 1.0e+10 ) ssh_bkginc(:,:) = 0.0
	420	ENDIF
	421
[3764]	422	IF ( ln_seaiceinc ) THEN
	423	CALL iom_get( inum, jpdom_autoglo, 'bckinseaice', seaice_bkginc, 1 )
	424	! Apply the masks
	425	seaice_bkginc(:,:) = seaice_bkginc(:,:) * tmask(:,:,1)
	426	! Set missing increments to 0.0 rather than 1e+20
	427	! to allow for differences in masks
	428	WHERE( ABS( seaice_bkginc(:,:) ) > 1.0e+10 ) seaice_bkginc(:,:) = 0.0
	429	ENDIF
[9213]	430	!
[2128]	431	CALL iom_close( inum )
[9213]	432	!
[2128]	433	ENDIF
[9213]	434	!
	435	! !--------------------------------------
	436	IF ( ln_dyninc .AND. nn_divdmp > 0 ) THEN ! Apply divergence damping filter
	437	! !--------------------------------------
[9019]	438	ALLOCATE( zhdiv(jpi,jpj) )
[5836]	439	!
	440	DO jt = 1, nn_divdmp
	441	!
[9019]	442	DO jk = 1, jpkm1 ! zhdiv = e1e1 * div
	443	zhdiv(:,:) = 0._wp
[3764]	444	DO jj = 2, jpjm1
	445	DO ji = fs_2, fs_jpim1 ! vector opt.
[9019]	446	zhdiv(ji,jj) = ( e2u(ji ,jj) * e3u_n(ji ,jj,jk) * u_bkginc(ji ,jj,jk) &
	447	& - e2u(ji-1,jj) * e3u_n(ji-1,jj,jk) * u_bkginc(ji-1,jj,jk) &
	448	& + e1v(ji,jj ) * e3v_n(ji,jj ,jk) * v_bkginc(ji,jj ,jk) &
	449	& - e1v(ji,jj-1) * e3v_n(ji,jj-1,jk) * v_bkginc(ji,jj-1,jk) ) / e3t_n(ji,jj,jk)
[3764]	450	END DO
[3294]	451	END DO
[10425]	452	CALL lbc_lnk( 'asminc', zhdiv, 'T', 1. ) ! lateral boundary cond. (no sign change)
[5836]	453	!
[3764]	454	DO jj = 2, jpjm1
	455	DO ji = fs_2, fs_jpim1 ! vector opt.
[6140]	456	u_bkginc(ji,jj,jk) = u_bkginc(ji,jj,jk) &
[9019]	457	& + 0.2_wp * ( zhdiv(ji+1,jj) - zhdiv(ji ,jj) ) * r1_e1u(ji,jj) * umask(ji,jj,jk)
[6140]	458	v_bkginc(ji,jj,jk) = v_bkginc(ji,jj,jk) &
[9019]	459	& + 0.2_wp * ( zhdiv(ji,jj+1) - zhdiv(ji,jj ) ) * r1_e2v(ji,jj) * vmask(ji,jj,jk)
[3764]	460	END DO
[3294]	461	END DO
	462	END DO
[5836]	463	!
[3764]	464	END DO
[5836]	465	!
[9019]	466	DEALLOCATE( zhdiv )
[5836]	467	!
[3294]	468	ENDIF
[9213]	469	!
	470	! !-----------------------------------------------------
	471	IF ( ln_asmdin ) THEN ! Allocate and initialize the background state arrays
	472	! !-----------------------------------------------------
[5836]	473	!
[9213]	474	ALLOCATE( t_bkg (jpi,jpj,jpk) ) ; t_bkg (:,:,:) = 0._wp
	475	ALLOCATE( s_bkg (jpi,jpj,jpk) ) ; s_bkg (:,:,:) = 0._wp
	476	ALLOCATE( u_bkg (jpi,jpj,jpk) ) ; u_bkg (:,:,:) = 0._wp
	477	ALLOCATE( v_bkg (jpi,jpj,jpk) ) ; v_bkg (:,:,:) = 0._wp
	478	ALLOCATE( ssh_bkg(jpi,jpj) ) ; ssh_bkg(:,:) = 0._wp
[5836]	479	!
	480	!
[2128]	481	!--------------------------------------------------------------------
	482	! Read from file the background state at analysis time
	483	!--------------------------------------------------------------------
[5836]	484	!
[2128]	485	CALL iom_open( c_asmdin, inum )
[5836]	486	!
[3764]	487	CALL iom_get( inum, 'rdastp', zdate_bkg )
[5836]	488	!
[2128]	489	IF(lwp) THEN
	490	WRITE(numout,*)
[9213]	491	WRITE(numout,*) ' ==>>> Assimilation background state valid at : ', zdate_bkg
	492	WRITE(numout,*)
[2128]	493	ENDIF
[5836]	494	!
[9213]	495	IF ( zdate_bkg /= ditdin_date ) &
[2128]	496	& CALL ctl_warn( ' Validity time of assimilation background state does', &
	497	& ' not agree with Direct Initialization time' )
[5836]	498	!
[2128]	499	IF ( ln_trainc ) THEN
	500	CALL iom_get( inum, jpdom_autoglo, 'tn', t_bkg )
	501	CALL iom_get( inum, jpdom_autoglo, 'sn', s_bkg )
	502	t_bkg(:,:,:) = t_bkg(:,:,:) * tmask(:,:,:)
	503	s_bkg(:,:,:) = s_bkg(:,:,:) * tmask(:,:,:)
	504	ENDIF
[5836]	505	!
[2128]	506	IF ( ln_dyninc ) THEN
	507	CALL iom_get( inum, jpdom_autoglo, 'un', u_bkg )
	508	CALL iom_get( inum, jpdom_autoglo, 'vn', v_bkg )
	509	u_bkg(:,:,:) = u_bkg(:,:,:) * umask(:,:,:)
	510	v_bkg(:,:,:) = v_bkg(:,:,:) * vmask(:,:,:)
	511	ENDIF
[5836]	512	!
[2128]	513	IF ( ln_sshinc ) THEN
	514	CALL iom_get( inum, jpdom_autoglo, 'sshn', ssh_bkg )
	515	ssh_bkg(:,:) = ssh_bkg(:,:) * tmask(:,:,1)
	516	ENDIF
[5836]	517	!
[2128]	518	CALL iom_close( inum )
[5836]	519	!
[2128]	520	ENDIF
[2392]	521	!
[9213]	522	IF(lwp) WRITE(numout,*) ' ==>>> Euler time step switch is ', neuler
	523	!
	524	IF( lk_asminc ) THEN !== data assimilation ==!
[15183]	525	! IF( ln_bkgwri ) CALL asm_bkg_wri( nit000 - 1 ) ! Output background fields
[9213]	526	IF( ln_asmdin ) THEN ! Direct initialization
	527	IF( ln_trainc ) CALL tra_asm_inc( nit000 - 1 ) ! Tracers
	528	IF( ln_dyninc ) CALL dyn_asm_inc( nit000 - 1 ) ! Dynamics
	529	IF( ln_sshinc ) CALL ssh_asm_inc( nit000 - 1 ) ! SSH
	530	ENDIF
	531	ENDIF
	532	!
[2128]	533	END SUBROUTINE asm_inc_init
[9213]	534
	535
[2128]	536	SUBROUTINE tra_asm_inc( kt )
	537	!!----------------------------------------------------------------------
	538	!! * ROUTINE tra_asm_inc *
	539	!!
	540	!! ** Purpose : Apply the tracer (T and S) assimilation increments
	541	!!
	542	!! ** Method : Direct initialization or Incremental Analysis Updating
	543	!!
	544	!! ** Action :
	545	!!----------------------------------------------------------------------
[5836]	546	INTEGER, INTENT(IN) :: kt ! Current time step
[2392]	547	!
[5836]	548	INTEGER :: ji, jj, jk
	549	INTEGER :: it
[2128]	550	REAL(wp) :: zincwgt ! IAU weight for current time step
[3764]	551	REAL (wp), DIMENSION(jpi,jpj,jpk) :: fzptnz ! 3d freezing point values
[2392]	552	!!----------------------------------------------------------------------
[5836]	553	!
[3764]	554	! freezing point calculation taken from oc_fz_pt (but calculated for all depths)
	555	! used to prevent the applied increments taking the temperature below the local freezing point
[4990]	556	DO jk = 1, jpkm1
[6140]	557	CALL eos_fzp( tsn(:,:,jk,jp_sal), fzptnz(:,:,jk), gdept_n(:,:,jk) )
[4990]	558	END DO
[5836]	559	!
	560	! !--------------------------------------
	561	IF ( ln_asmiau ) THEN ! Incremental Analysis Updating
	562	! !--------------------------------------
	563	!
[2128]	564	IF ( ( kt >= nitiaustr_r ).AND.( kt <= nitiaufin_r ) ) THEN
[5836]	565	!
[2128]	566	it = kt - nit000 + 1
	567	zincwgt = wgtiau(it) / rdt ! IAU weight for the current time step
[5836]	568	!
[2128]	569	IF(lwp) THEN
	570	WRITE(numout,*)
[4990]	571	WRITE(numout,*) 'tra_asm_inc : Tracer IAU at time step = ', kt,' with IAU weight = ', wgtiau(it)
[2128]	572	WRITE(numout,*) '~~~~~~~~~~~~'
	573	ENDIF
[5836]	574	!
[2128]	575	! Update the tracer tendencies
	576	DO jk = 1, jpkm1
[3764]	577	IF (ln_temnofreeze) THEN
	578	! Do not apply negative increments if the temperature will fall below freezing
	579	WHERE(t_bkginc(:,:,jk) > 0.0_wp .OR. &
	580	& tsn(:,:,jk,jp_tem) + tsa(:,:,jk,jp_tem) + t_bkginc(:,:,jk) * wgtiau(it) > fzptnz(:,:,jk) )
	581	tsa(:,:,jk,jp_tem) = tsa(:,:,jk,jp_tem) + t_bkginc(:,:,jk) * zincwgt
	582	END WHERE
	583	ELSE
	584	tsa(:,:,jk,jp_tem) = tsa(:,:,jk,jp_tem) + t_bkginc(:,:,jk) * zincwgt
	585	ENDIF
	586	IF (ln_salfix) THEN
	587	! Do not apply negative increments if the salinity will fall below a specified
	588	! minimum value salfixmin
	589	WHERE(s_bkginc(:,:,jk) > 0.0_wp .OR. &
	590	& tsn(:,:,jk,jp_sal) + tsa(:,:,jk,jp_sal) + s_bkginc(:,:,jk) * wgtiau(it) > salfixmin )
	591	tsa(:,:,jk,jp_sal) = tsa(:,:,jk,jp_sal) + s_bkginc(:,:,jk) * zincwgt
	592	END WHERE
	593	ELSE
	594	tsa(:,:,jk,jp_sal) = tsa(:,:,jk,jp_sal) + s_bkginc(:,:,jk) * zincwgt
	595	ENDIF
[2128]	596	END DO
[5836]	597	!
[2128]	598	ENDIF
[5836]	599	!
[2128]	600	IF ( kt == nitiaufin_r + 1 ) THEN ! For bias crcn to work
	601	DEALLOCATE( t_bkginc )
	602	DEALLOCATE( s_bkginc )
	603	ENDIF
[5836]	604	! !--------------------------------------
	605	ELSEIF ( ln_asmdin ) THEN ! Direct Initialization
	606	! !--------------------------------------
	607	!
[2128]	608	IF ( kt == nitdin_r ) THEN
[5836]	609	!
[2128]	610	neuler = 0 ! Force Euler forward step
[5836]	611	!
[2128]	612	! Initialize the now fields with the background + increment
[3764]	613	IF (ln_temnofreeze) THEN
	614	! Do not apply negative increments if the temperature will fall below freezing
[4990]	615	WHERE( t_bkginc(:,:,:) > 0.0_wp .OR. tsn(:,:,:,jp_tem) + t_bkginc(:,:,:) > fzptnz(:,:,:) )
[3764]	616	tsn(:,:,:,jp_tem) = t_bkg(:,:,:) + t_bkginc(:,:,:)
	617	END WHERE
	618	ELSE
	619	tsn(:,:,:,jp_tem) = t_bkg(:,:,:) + t_bkginc(:,:,:)
	620	ENDIF
[2128]	621	IF (ln_salfix) THEN
[3764]	622	! Do not apply negative increments if the salinity will fall below a specified
	623	! minimum value salfixmin
[4990]	624	WHERE( s_bkginc(:,:,:) > 0.0_wp .OR. tsn(:,:,:,jp_sal) + s_bkginc(:,:,:) > salfixmin )
[3764]	625	tsn(:,:,:,jp_sal) = s_bkg(:,:,:) + s_bkginc(:,:,:)
	626	END WHERE
	627	ELSE
	628	tsn(:,:,:,jp_sal) = s_bkg(:,:,:) + s_bkginc(:,:,:)
[2128]	629	ENDIF
	630
[4990]	631	tsb(:,:,:,:) = tsn(:,:,:,:) ! Update before fields
[2128]	632
[4990]	633	CALL eos( tsb, rhd, rhop, gdept_0(:,:,:) ) ! Before potential and in situ densities
	634	!!gm fabien
	635	! CALL eos( tsb, rhd, rhop ) ! Before potential and in situ densities
	636	!!gm
	637
[6140]	638	IF( ln_zps .AND. .NOT. lk_c1d .AND. .NOT. ln_isfcav) &
	639	& CALL zps_hde ( kt, jpts, tsb, gtsu, gtsv, & ! Partial steps: before horizontal gradient
	640	& rhd, gru , grv ) ! of t, s, rd at the last ocean level
	641	IF( ln_zps .AND. .NOT. lk_c1d .AND. ln_isfcav) &
	642	& CALL zps_hde_isf( nit000, jpts, tsb, gtsu, gtsv, gtui, gtvi, & ! Partial steps for top cell (ISF)
	643	& rhd, gru , grv , grui, grvi ) ! of t, s, rd at the last ocean level
	644
[2128]	645	DEALLOCATE( t_bkginc )
	646	DEALLOCATE( s_bkginc )
	647	DEALLOCATE( t_bkg )
	648	DEALLOCATE( s_bkg )
	649	ENDIF
[2392]	650	!
[2128]	651	ENDIF
[3764]	652	! Perhaps the following call should be in step
[5836]	653	IF ( ln_seaiceinc ) CALL seaice_asm_inc ( kt ) ! apply sea ice concentration increment
[2392]	654	!
[2128]	655	END SUBROUTINE tra_asm_inc
	656
[2392]	657
[2128]	658	SUBROUTINE dyn_asm_inc( kt )
	659	!!----------------------------------------------------------------------
	660	!! * ROUTINE dyn_asm_inc *
	661	!!
	662	!! ** Purpose : Apply the dynamics (u and v) assimilation increments.
	663	!!
	664	!! ** Method : Direct initialization or Incremental Analysis Updating.
	665	!!
	666	!! ** Action :
	667	!!----------------------------------------------------------------------
	668	INTEGER, INTENT(IN) :: kt ! Current time step
[2392]	669	!
[2128]	670	INTEGER :: jk
	671	INTEGER :: it
	672	REAL(wp) :: zincwgt ! IAU weight for current time step
[2392]	673	!!----------------------------------------------------------------------
[5836]	674	!
	675	! !--------------------------------------------
	676	IF ( ln_asmiau ) THEN ! Incremental Analysis Updating
	677	! !--------------------------------------------
	678	!
[2128]	679	IF ( ( kt >= nitiaustr_r ).AND.( kt <= nitiaufin_r ) ) THEN
[5836]	680	!
[2128]	681	it = kt - nit000 + 1
	682	zincwgt = wgtiau(it) / rdt ! IAU weight for the current time step
[5836]	683	!
[2128]	684	IF(lwp) THEN
	685	WRITE(numout,*)
[5836]	686	WRITE(numout,*) 'dyn_asm_inc : Dynamics IAU at time step = ', kt,' with IAU weight = ', wgtiau(it)
[2128]	687	WRITE(numout,*) '~~~~~~~~~~~~'
	688	ENDIF
[5836]	689	!
[2128]	690	! Update the dynamic tendencies
	691	DO jk = 1, jpkm1
	692	ua(:,:,jk) = ua(:,:,jk) + u_bkginc(:,:,jk) * zincwgt
	693	va(:,:,jk) = va(:,:,jk) + v_bkginc(:,:,jk) * zincwgt
	694	END DO
[5836]	695	!
[2128]	696	IF ( kt == nitiaufin_r ) THEN
	697	DEALLOCATE( u_bkginc )
	698	DEALLOCATE( v_bkginc )
	699	ENDIF
[5836]	700	!
[2128]	701	ENDIF
[5836]	702	! !-----------------------------------------
	703	ELSEIF ( ln_asmdin ) THEN ! Direct Initialization
	704	! !-----------------------------------------
	705	!
[2128]	706	IF ( kt == nitdin_r ) THEN
[5836]	707	!
[2128]	708	neuler = 0 ! Force Euler forward step
[5836]	709	!
[2128]	710	! Initialize the now fields with the background + increment
	711	un(:,:,:) = u_bkg(:,:,:) + u_bkginc(:,:,:)
	712	vn(:,:,:) = v_bkg(:,:,:) + v_bkginc(:,:,:)
[5836]	713	!
[2128]	714	ub(:,:,:) = un(:,:,:) ! Update before fields
	715	vb(:,:,:) = vn(:,:,:)
[5836]	716	!
[2128]	717	DEALLOCATE( u_bkg )
	718	DEALLOCATE( v_bkg )
	719	DEALLOCATE( u_bkginc )
	720	DEALLOCATE( v_bkginc )
	721	ENDIF
[2392]	722	!
[2128]	723	ENDIF
[2392]	724	!
[2128]	725	END SUBROUTINE dyn_asm_inc
	726
[2392]	727
[2128]	728	SUBROUTINE ssh_asm_inc( kt )
	729	!!----------------------------------------------------------------------
	730	!! * ROUTINE ssh_asm_inc *
	731	!!
	732	!! ** Purpose : Apply the sea surface height assimilation increment.
	733	!!
	734	!! ** Method : Direct initialization or Incremental Analysis Updating.
	735	!!
	736	!! ** Action :
	737	!!----------------------------------------------------------------------
	738	INTEGER, INTENT(IN) :: kt ! Current time step
[2392]	739	!
[2128]	740	INTEGER :: it
[3764]	741	INTEGER :: jk
[2128]	742	REAL(wp) :: zincwgt ! IAU weight for current time step
[2392]	743	!!----------------------------------------------------------------------
[5836]	744	!
	745	! !-----------------------------------------
	746	IF ( ln_asmiau ) THEN ! Incremental Analysis Updating
	747	! !-----------------------------------------
	748	!
[2128]	749	IF ( ( kt >= nitiaustr_r ).AND.( kt <= nitiaufin_r ) ) THEN
[5836]	750	!
[2128]	751	it = kt - nit000 + 1
	752	zincwgt = wgtiau(it) / rdt ! IAU weight for the current time step
[5836]	753	!
[2128]	754	IF(lwp) THEN
	755	WRITE(numout,*)
	756	WRITE(numout,*) 'ssh_asm_inc : SSH IAU at time step = ', &
	757	& kt,' with IAU weight = ', wgtiau(it)
	758	WRITE(numout,*) '~~~~~~~~~~~~'
	759	ENDIF
[5836]	760	!
[2128]	761	! Save the tendency associated with the IAU weighted SSH increment
	762	! (applied in dynspg.*)
	763	#if defined key_asminc
	764	ssh_iau(:,:) = ssh_bkginc(:,:) * zincwgt
	765	#endif
[5836]	766	!
[8547]	767	ELSE IF( kt == nitiaufin_r+1 ) THEN
[8546]	768	!
[9465]	769	! test on ssh_bkginc needed as ssh_asm_inc is called twice by time step
	770	IF (ALLOCATED(ssh_bkginc)) DEALLOCATE( ssh_bkginc )
	771	!
	772	#if defined key_asminc
[8546]	773	ssh_iau(:,:) = 0._wp
[9465]	774	#endif
[8546]	775	!
[2128]	776	ENDIF
[5836]	777	! !-----------------------------------------
	778	ELSEIF ( ln_asmdin ) THEN ! Direct Initialization
	779	! !-----------------------------------------
	780	!
[2128]	781	IF ( kt == nitdin_r ) THEN
[5836]	782	!
	783	neuler = 0 ! Force Euler forward step
	784	!
	785	sshn(:,:) = ssh_bkg(:,:) + ssh_bkginc(:,:) ! Initialize the now fields the background + increment
	786	!
	787	sshb(:,:) = sshn(:,:) ! Update before fields
[6140]	788	e3t_b(:,:,:) = e3t_n(:,:,:)
	789	!!gm why not e3u_b, e3v_b, gdept_b ????
[5836]	790	!
[2128]	791	DEALLOCATE( ssh_bkg )
	792	DEALLOCATE( ssh_bkginc )
[5836]	793	!
[2128]	794	ENDIF
[2392]	795	!
[2128]	796	ENDIF
[2392]	797	!
[2128]	798	END SUBROUTINE ssh_asm_inc
	799
[9213]	800
[9023]	801	SUBROUTINE ssh_asm_div( kt, phdivn )
	802	!!----------------------------------------------------------------------
	803	!! * ROUTINE ssh_asm_div *
	804	!!
	805	!! ** Purpose : ssh increment with z* is incorporated via a correction of the local divergence
	806	!! across all the water column
	807	!!
	808	!! ** Method :
	809	!! CAUTION : sshiau is positive (inflow) decreasing the
	810	!! divergence and expressed in m/s
	811	!!
	812	!! ** Action : phdivn decreased by the ssh increment
	813	!!----------------------------------------------------------------------
	814	INTEGER, INTENT(IN) :: kt ! ocean time-step index
	815	REAL(wp), DIMENSION(:,:,:), INTENT(inout) :: phdivn ! horizontal divergence
	816	!!
	817	INTEGER :: jk ! dummy loop index
	818	REAL(wp), DIMENSION(:,:) , POINTER :: ztim ! local array
	819	!!----------------------------------------------------------------------
	820	!
	821	#if defined key_asminc
	822	CALL ssh_asm_inc( kt ) !== (calculate increments)
	823	!
	824	IF( ln_linssh ) THEN
	825	phdivn(:,:,1) = phdivn(:,:,1) - ssh_iau(:,:) / e3t_n(:,:,1) * tmask(:,:,1)
	826	ELSE
[9044]	827	ALLOCATE( ztim(jpi,jpj) )
[9023]	828	ztim(:,:) = ssh_iau(:,:) / ( ht_n(:,:) + 1.0 - ssmask(:,:) )
	829	DO jk = 1, jpkm1
	830	phdivn(:,:,jk) = phdivn(:,:,jk) - ztim(:,:) * tmask(:,:,jk)
	831	END DO
	832	!
[9044]	833	DEALLOCATE(ztim)
[9023]	834	ENDIF
	835	#endif
	836	!
	837	END SUBROUTINE ssh_asm_div
[3785]	838
[9213]	839
[3764]	840	SUBROUTINE seaice_asm_inc( kt, kindic )
	841	!!----------------------------------------------------------------------
	842	!! * ROUTINE seaice_asm_inc *
	843	!!
	844	!! ** Purpose : Apply the sea ice assimilation increment.
	845	!!
	846	!! ** Method : Direct initialization or Incremental Analysis Updating.
	847	!!
	848	!! ** Action :
	849	!!
	850	!!----------------------------------------------------------------------
[5836]	851	INTEGER, INTENT(in) :: kt ! Current time step
[3785]	852	INTEGER, INTENT(in), OPTIONAL :: kindic ! flag for disabling the deallocation
	853	!
	854	INTEGER :: it
	855	REAL(wp) :: zincwgt ! IAU weight for current time step
[9570]	856	#if defined key_si3
[9656]	857	REAL(wp), DIMENSION(jpi,jpj) :: zofrld, zohicif, zseaicendg, zhicifinc
[3785]	858	REAL(wp) :: zhicifmin = 0.5_wp ! ice minimum depth in metres
[3764]	859	#endif
[3785]	860	!!----------------------------------------------------------------------
[5836]	861	!
	862	! !-----------------------------------------
	863	IF ( ln_asmiau ) THEN ! Incremental Analysis Updating
	864	! !-----------------------------------------
	865	!
[3764]	866	IF ( ( kt >= nitiaustr_r ).AND.( kt <= nitiaufin_r ) ) THEN
[5836]	867	!
[3764]	868	it = kt - nit000 + 1
	869	zincwgt = wgtiau(it) ! IAU weight for the current time step
	870	! note this is not a tendency so should not be divided by rdt (as with the tracer and other increments)
[5836]	871	!
[3764]	872	IF(lwp) THEN
	873	WRITE(numout,*)
[5836]	874	WRITE(numout,*) 'seaice_asm_inc : sea ice conc IAU at time step = ', kt,' with IAU weight = ', wgtiau(it)
[3764]	875	WRITE(numout,*) '~~~~~~~~~~~~'
	876	ENDIF
[5836]	877	!
[9656]	878	! Sea-ice : SI3 case
[5836]	879	!
[9570]	880	#if defined key_si3
[9019]	881	zofrld (:,:) = 1._wp - at_i(:,:)
	882	zohicif(:,:) = hm_i(:,:)
[3785]	883	!
[9019]	884	at_i (:,:) = 1. - MIN( MAX( 1.-at_i (:,:) - seaice_bkginc(:,:) * zincwgt, 0.0_wp), 1.0_wp)
	885	at_i_b(:,:) = 1. - MIN( MAX( 1.-at_i_b(:,:) - seaice_bkginc(:,:) * zincwgt, 0.0_wp), 1.0_wp)
	886	fr_i(:,:) = at_i(:,:) ! adjust ice fraction
[3785]	887	!
[9019]	888	zseaicendg(:,:) = zofrld(:,:) - (1. - at_i(:,:)) ! find out actual sea ice nudge applied
[3785]	889	!
[3764]	890	! Nudge sea ice depth to bring it up to a required minimum depth
[9019]	891	WHERE( zseaicendg(:,:) > 0.0_wp .AND. hm_i(:,:) < zhicifmin )
	892	zhicifinc(:,:) = (zhicifmin - hm_i(:,:)) * zincwgt
[3764]	893	ELSEWHERE
	894	zhicifinc(:,:) = 0.0_wp
	895	END WHERE
[3785]	896	!
	897	! nudge ice depth
[9019]	898	hm_i (:,:) = hm_i (:,:) + zhicifinc(:,:)
[3785]	899	!
	900	! seaice salinity balancing (to add)
[3764]	901	#endif
[9213]	902	!
[4245]	903	#if defined key_cice && defined key_asminc
[3785]	904	! Sea-ice : CICE case. Pass ice increment tendency into CICE
[3764]	905	ndaice_da(:,:) = seaice_bkginc(:,:) * zincwgt / rdt
	906	#endif
[9213]	907	!
[3764]	908	IF ( kt == nitiaufin_r ) THEN
	909	DEALLOCATE( seaice_bkginc )
	910	ENDIF
[9213]	911	!
[3764]	912	ELSE
[9213]	913	!
[4245]	914	#if defined key_cice && defined key_asminc
[5836]	915	ndaice_da(:,:) = 0._wp ! Sea-ice : CICE case. Zero ice increment tendency into CICE
[3764]	916	#endif
[9213]	917	!
[3764]	918	ENDIF
[5836]	919	! !-----------------------------------------
	920	ELSEIF ( ln_asmdin ) THEN ! Direct Initialization
	921	! !-----------------------------------------
	922	!
[3764]	923	IF ( kt == nitdin_r ) THEN
[5836]	924	!
[3764]	925	neuler = 0 ! Force Euler forward step
[5836]	926	!
[9656]	927	! Sea-ice : SI3 case
[5836]	928	!
[9570]	929	#if defined key_si3
[9019]	930	zofrld (:,:) = 1._wp - at_i(:,:)
	931	zohicif(:,:) = hm_i(:,:)
[3785]	932	!
[3764]	933	! Initialize the now fields the background + increment
[9019]	934	at_i(:,:) = 1. - MIN( MAX( 1.-at_i(:,:) - seaice_bkginc(:,:), 0.0_wp), 1.0_wp)
	935	at_i_b(:,:) = at_i(:,:)
	936	fr_i(:,:) = at_i(:,:) ! adjust ice fraction
[3785]	937	!
[9019]	938	zseaicendg(:,:) = zofrld(:,:) - (1. - at_i(:,:)) ! find out actual sea ice nudge applied
	939	!
[3764]	940	! Nudge sea ice depth to bring it up to a required minimum depth
[9019]	941	WHERE( zseaicendg(:,:) > 0.0_wp .AND. hm_i(:,:) < zhicifmin )
[10355]	942	zhicifinc(:,:) = zhicifmin - hm_i(:,:)
[3764]	943	ELSEWHERE
[9019]	944	zhicifinc(:,:) = 0.0_wp
[3764]	945	END WHERE
[3785]	946	!
	947	! nudge ice depth
[9019]	948	hm_i (:,:) = hm_i (:,:) + zhicifinc(:,:)
[3785]	949	!
	950	! seaice salinity balancing (to add)
[3764]	951	#endif
[5836]	952	!
[4245]	953	#if defined key_cice && defined key_asminc
	954	! Sea-ice : CICE case. Pass ice increment tendency into CICE
[3764]	955	ndaice_da(:,:) = seaice_bkginc(:,:) / rdt
	956	#endif
[5836]	957	IF ( .NOT. PRESENT(kindic) ) THEN
	958	DEALLOCATE( seaice_bkginc )
	959	END IF
	960	!
[3764]	961	ELSE
[5836]	962	!
	963	#if defined key_cice && defined key_asminc
	964	ndaice_da(:,:) = 0._wp ! Sea-ice : CICE case. Zero ice increment tendency into CICE
[3764]	965	#endif
[5836]	966	!
[3764]	967	ENDIF
	968
[9570]	969	!#if defined defined key_si3 \|\| defined key_cice
[3764]	970	!
	971	! IF (ln_seaicebal ) THEN
	972	! !! balancing salinity increments
	973	! !! simple case from limflx.F90 (doesn't include a mass flux)
	974	! !! assumption is that as ice concentration is reduced or increased
	975	! !! the snow and ice depths remain constant
	976	! !! note that snow is being created where ice concentration is being increased
	977	! !! - could be more sophisticated and
	978	! !! not do this (but would need to alter h_snow)
	979	!
	980	! usave(:,:,:)=sb(:,:,:) ! use array as a temporary store
	981	!
	982	! DO jj = 1, jpj
	983	! DO ji = 1, jpi
	984	! ! calculate change in ice and snow mass per unit area
	985	! ! positive values imply adding salt to the ocean (results from ice formation)
	986	! ! fwf : ice formation and melting
	987	!
	988	! zfons = ( -nfresh_da(ji,jj)soce + nfsalt_da(ji,jj) )rdt
	989	!
	990	! ! change salinity down to mixed layer depth
	991	! mld=hmld_kara(ji,jj)
	992	!
	993	! ! prevent small mld
	994	! ! less than 10m can cause salinity instability
	995	! IF (mld < 10) mld=10
	996	!
	997	! ! set to bottom of a level
	998	! DO jk = jpk-1, 2, -1
	999	! IF ((mld > gdepw(ji,jj,jk)) .and. (mld < gdepw(ji,jj,jk+1))) THEN
	1000	! mld=gdepw(ji,jj,jk+1)
	1001	! jkmax=jk
	1002	! ENDIF
	1003	! ENDDO
	1004	!
	1005	! ! avoid applying salinity balancing in shallow water or on land
	1006	! !
	1007	!
	1008	! ! dsal_ocn (psu kg m^-2) / (kg m^-3 * m)
	1009	!
	1010	! dsal_ocn=0.0_wp
	1011	! sal_thresh=5.0_wp ! minimum salinity threshold for salinity balancing
	1012	!
	1013	! if (tmask(ji,jj,1) > 0 .AND. tmask(ji,jj,jkmax) > 0 ) &
	1014	! dsal_ocn = zfons / (rhop(ji,jj,1) * mld)
	1015	!
	1016	! ! put increments in for levels in the mixed layer
	1017	! ! but prevent salinity below a threshold value
	1018	!
	1019	! DO jk = 1, jkmax
	1020	!
	1021	! IF (dsal_ocn > 0.0_wp .or. sb(ji,jj,jk)+dsal_ocn > sal_thresh) THEN
	1022	! sb(ji,jj,jk) = sb(ji,jj,jk) + dsal_ocn
	1023	! sn(ji,jj,jk) = sn(ji,jj,jk) + dsal_ocn
	1024	! ENDIF
	1025	!
	1026	! ENDDO
	1027	!
	1028	! ! ! salt exchanges at the ice/ocean interface
	1029	! ! zpmess = zfons / rdt_ice ! rdt_ice is ice timestep
	1030	! !
	1031	! !! Adjust fsalt. A +ve fsalt means adding salt to ocean
	1032	! !! fsalt(ji,jj) = fsalt(ji,jj) + zpmess ! adjust fsalt
	1033	! !!
	1034	! !! emps(ji,jj) = emps(ji,jj) + zpmess ! or adjust emps (see icestp1d)
	1035	! !! ! E-P (kg m-2 s-2)
	1036	! ! emp(ji,jj) = emp(ji,jj) + zpmess ! E-P (kg m-2 s-2)
	1037	! ENDDO !ji
	1038	! ENDDO !jj!
	1039	!
	1040	! ENDIF !ln_seaicebal
	1041	!
	1042	!#endif
[5836]	1043	!
[3764]	1044	ENDIF
[5836]	1045	!
[3764]	1046	END SUBROUTINE seaice_asm_inc
[3785]	1047
[2392]	1048	!!======================================================================
[2128]	1049	END MODULE asminc

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source: NEMO/branches/UKMO/NEMO_4.0.4_CO9_OBS_ASM/src/OCE/ASM/asminc.F90

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