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asminc.F90 in branches/UKMO/dev_r5518_obs_oper_update/NEMOGCM/NEMO/OPA_SRC/ASM – NEMO

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source: branches/UKMO/dev_r5518_obs_oper_update/NEMOGCM/NEMO/OPA_SRC/ASM/asminc.F90 @ 12610

Last change on this file since 12610 was 12610, checked in by dcarneir, 4 years ago
Inclusion of sea ice thickness in OBS branch
File size: 54.0 KB

Line
1	MODULE asminc
2	!!======================================================================
3	!! * MODULE asminc *
4	!! Assimilation increment : Apply an increment generated by data
5	!! assimilation
6	!!======================================================================
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
12	!! 3.4 ! 2012-10 (A. Weaver and K. Mogensen) Fix for direct initialization
13	!!----------------------------------------------------------------------
14
15	!!----------------------------------------------------------------------
16	!! 'key_asminc' : Switch on the assimilation increment interface
17	!!----------------------------------------------------------------------
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 sea ice concentration increment
24	!! sit_asm_inc : Apply the sea ice thickness increment
25	!!----------------------------------------------------------------------
26	USE wrk_nemo ! Memory Allocation
27	USE par_oce ! Ocean space and time domain variables
28	USE dom_oce ! Ocean space and time domain
29	USE domvvl ! domain: variable volume level
30	USE oce ! Dynamics and active tracers defined in memory
31	USE ldfdyn_oce ! ocean dynamics: lateral physics
32	USE eosbn2 ! Equation of state - in situ and potential density
33	USE zpshde ! Partial step : Horizontal Derivative
34	USE iom ! Library to read input files
35	USE asmpar ! Parameters for the assmilation interface
36	USE c1d ! 1D initialization
37	USE in_out_manager ! I/O manager
38	USE lib_mpp ! MPP library
39	#if defined key_lim2
40	USE ice_2 ! LIM2
41	#endif
42	USE sbc_oce ! Surface boundary condition variables.
43
44	IMPLICIT NONE
45	PRIVATE
46
47	PUBLIC asm_inc_init !: Initialize the increment arrays and IAU weights
48	PUBLIC calc_date !: Compute the calendar date YYYYMMDD on a given step
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
52	PUBLIC seaice_asm_inc !: Apply the seaice concentration increment
53	PUBLIC sit_asm_inc !: Apply the seaice thickness increment
54	PUBLIC bgc_asm_inc !: Apply the biogeochemistry increments
55
56	#if defined key_asminc
57	LOGICAL, PUBLIC, PARAMETER :: lk_asminc = .TRUE. !: Logical switch for assimilation increment interface
58	#else
59	LOGICAL, PUBLIC, PARAMETER :: lk_asminc = .FALSE. !: No assimilation increments
60	#endif
61	LOGICAL, PUBLIC :: ln_bkgwri = .FALSE. !: No output of the background state fields
62	LOGICAL, PUBLIC :: ln_avgbkg = .FALSE. !: No output of the mean background state fields
63	LOGICAL, PUBLIC :: ln_asmiau = .FALSE. !: No applying forcing with an assimilation increment
64	LOGICAL, PUBLIC :: ln_asmdin = .FALSE. !: No direct initialization
65	LOGICAL, PUBLIC :: ln_trainc = .FALSE. !: No tracer (T and S) assimilation increments
66	LOGICAL, PUBLIC :: ln_dyninc = .FALSE. !: No dynamics (u and v) assimilation increments
67	LOGICAL, PUBLIC :: ln_sshinc = .FALSE. !: No sea surface height assimilation increment
68	LOGICAL, PUBLIC :: ln_seaiceinc = .FALSE. !: No sea ice concentration increment
69	LOGICAL, PUBLIC :: ln_sitinc = .FALSE. !: No sea ice thickness increment
70	LOGICAL, PUBLIC :: lk_bgcinc = .FALSE. !: No biogeochemistry increments
71	LOGICAL, PUBLIC :: ln_salfix = .FALSE. !: Apply minimum salinity check
72	LOGICAL, PUBLIC :: ln_temnofreeze = .FALSE. !: Don't allow the temperature to drop below freezing
73	INTEGER, PUBLIC :: nn_divdmp !: Apply divergence damping filter nn_divdmp times
74
75	REAL(wp), PUBLIC, DIMENSION(:,:,:), ALLOCATABLE :: t_bkg , s_bkg !: Background temperature and salinity
76	REAL(wp), PUBLIC, DIMENSION(:,:,:), ALLOCATABLE :: u_bkg , v_bkg !: Background u- & v- velocity components
77	REAL(wp), PUBLIC, DIMENSION(:,:,:), ALLOCATABLE :: t_bkginc, s_bkginc !: Increment to the background T & S
78	REAL(wp), PUBLIC, DIMENSION(:,:,:), ALLOCATABLE :: u_bkginc, v_bkginc !: Increment to the u- & v-components
79	REAL(wp), PUBLIC, DIMENSION(:) , ALLOCATABLE :: wgtiau !: IAU weights for each time step
80	REAL(wp), PUBLIC, DIMENSION(:,:), ALLOCATABLE :: ssh_iau !: IAU-weighted sea surface height increment
81	! !!! time steps relative to the cycle interval [0,nitend-nit000-1]
82	INTEGER , PUBLIC :: nitbkg !: Time step of the background state used in the Jb term
83	INTEGER , PUBLIC :: nitdin !: Time step of the background state for direct initialization
84	INTEGER , PUBLIC :: nitiaustr !: Time step of the start of the IAU interval
85	INTEGER , PUBLIC :: nitiaufin !: Time step of the end of the IAU interval
86	!
87	INTEGER , PUBLIC :: niaufn !: Type of IAU weighing function: = 0 Constant weighting
88	! !: = 1 Linear hat-like, centred in middle of IAU interval
89	REAL(wp), PUBLIC :: salfixmin !: Ensure that the salinity is larger than this value if (ln_salfix)
90
91	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: ssh_bkg, ssh_bkginc ! Background sea surface height and its increment
92	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: seaice_bkginc ! Increment to the background sea ice conc
93	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: sit_bkginc ! Increment to the background sea ice thickness
94
95	!! * Substitutions
96	# include "domzgr_substitute.h90"
97	# include "ldfdyn_substitute.h90"
98	# include "vectopt_loop_substitute.h90"
99	!!----------------------------------------------------------------------
100	!! NEMO/OPA 3.3 , NEMO Consortium (2010)
101	!! $Id$
102	!! Software governed by the CeCILL licence (NEMOGCM/NEMO_CeCILL.txt)
103	!!----------------------------------------------------------------------
104	CONTAINS
105
106	SUBROUTINE asm_inc_init
107	!!----------------------------------------------------------------------
108	!! * ROUTINE asm_inc_init *
109	!!
110	!! ** Purpose : Initialize the assimilation increment and IAU weights.
111	!!
112	!! ** Method : Initialize the assimilation increment and IAU weights.
113	!!
114	!! ** Action :
115	!!----------------------------------------------------------------------
116	INTEGER :: ji, jj, jk, jt ! dummy loop indices
117	INTEGER :: imid, inum ! local integers
118	INTEGER :: ios ! Local integer output status for namelist read
119	INTEGER :: iiauper ! Number of time steps in the IAU period
120	INTEGER :: icycper ! Number of time steps in the cycle
121	INTEGER :: iitend_date ! Date YYYYMMDD of final time step
122	INTEGER :: iitbkg_date ! Date YYYYMMDD of background time step for Jb term
123	INTEGER :: iitdin_date ! Date YYYYMMDD of background time step for DI
124	INTEGER :: iitiaustr_date ! Date YYYYMMDD of IAU interval start time step
125	INTEGER :: iitiaufin_date ! Date YYYYMMDD of IAU interval final time step
126	!
127	REAL(wp) :: znorm ! Normalization factor for IAU weights
128	REAL(wp) :: ztotwgt ! Value of time-integrated IAU weights (should be equal to one)
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
133	!
134	REAL(wp), POINTER, DIMENSION(:,:) :: hdiv ! 2D workspace
135	!!
136	NAMELIST/nam_asminc/ ln_bkgwri, ln_avgbkg, ln_balwri, &
137	& ln_trainc, ln_dyninc, ln_sshinc, &
138	& ln_asmdin, ln_asmiau, &
139	& nitbkg, nitdin, nitiaustr, nitiaufin, niaufn, &
140	& ln_salfix, salfixmin, nn_divdmp
141	!!----------------------------------------------------------------------
142
143	!-----------------------------------------------------------------------
144	! Read Namelist nam_asminc : assimilation increment interface
145	!-----------------------------------------------------------------------
146	ln_seaiceinc = .FALSE.
147	ln_sitinc = .FALSE.
148	ln_temnofreeze = .FALSE.
149
150	REWIND( numnam_ref ) ! Namelist nam_asminc in reference namelist : Assimilation increment
151	READ ( numnam_ref, nam_asminc, IOSTAT = ios, ERR = 901)
152	901 IF( ios /= 0 ) CALL ctl_nam ( ios , 'nam_asminc in reference namelist', lwp )
153
154	REWIND( numnam_cfg ) ! Namelist nam_asminc in configuration namelist : Assimilation increment
155	READ ( numnam_cfg, nam_asminc, IOSTAT = ios, ERR = 902 )
156	902 IF( ios /= 0 ) CALL ctl_nam ( ios , 'nam_asminc in configuration namelist', lwp )
157	IF(lwm) WRITE ( numond, nam_asminc )
158
159	! Control print
160	IF(lwp) THEN
161	WRITE(numout,*)
162	WRITE(numout,*) 'asm_inc_init : Assimilation increment initialization :'
163	WRITE(numout,*) '~~~~~~~~~~~~'
164	WRITE(numout,*) ' Namelist nam_asminc : set assimilation increment parameters'
165	WRITE(numout,*) ' Logical switch for writing out background state ln_bkgwri = ', ln_bkgwri
166	WRITE(numout,*) ' Logical switch for writing mean background state ln_avgbkg = ', ln_avgbkg
167	WRITE(numout,*) ' Logical switch for writing out balancing increments ln_balwri = ', ln_balwri
168	WRITE(numout,*) ' Logical switch for applying tracer increments ln_trainc = ', ln_trainc
169	WRITE(numout,*) ' Logical switch for applying velocity increments ln_dyninc = ', ln_dyninc
170	WRITE(numout,*) ' Logical switch for applying SSH increments ln_sshinc = ', ln_sshinc
171	WRITE(numout,*) ' Logical switch for applying SIC increments ln_seaiceinc = ', ln_seaiceinc
172	WRITE(numout,*) ' Logical switch for applying SIT increments ln_sitinc = ', ln_sitinc
173	WRITE(numout,*) ' Logical switch for Direct Initialization (DI) ln_asmdin = ', ln_asmdin
174	WRITE(numout,*) ' Logical switch for Incremental Analysis Updating (IAU) ln_asmiau = ', ln_asmiau
175	WRITE(numout,*) ' Timestep of background in [0,nitend-nit000-1] nitbkg = ', nitbkg
176	WRITE(numout,*) ' Timestep of background for DI in [0,nitend-nit000-1] nitdin = ', nitdin
177	WRITE(numout,*) ' Timestep of start of IAU interval in [0,nitend-nit000-1] nitiaustr = ', nitiaustr
178	WRITE(numout,*) ' Timestep of end of IAU interval in [0,nitend-nit000-1] nitiaufin = ', nitiaufin
179	WRITE(numout,*) ' Type of IAU weighting function niaufn = ', niaufn
180	WRITE(numout,*) ' Logical switch for ensuring that the sa > salfixmin ln_salfix = ', ln_salfix
181	WRITE(numout,*) ' Minimum salinity after applying the increments salfixmin = ', salfixmin
182	ENDIF
183
184	nitbkg_r = nitbkg + nit000 - 1 ! Background time referenced to nit000
185	nitdin_r = nitdin + nit000 - 1 ! Background time for DI referenced to nit000
186	nitiaustr_r = nitiaustr + nit000 - 1 ! Start of IAU interval referenced to nit000
187	nitiaufin_r = nitiaufin + nit000 - 1 ! End of IAU interval referenced to nit000
188
189	iiauper = nitiaufin_r - nitiaustr_r + 1 ! IAU interval length
190	icycper = nitend - nit000 + 1 ! Cycle interval length
191
192	CALL calc_date( nit000, nitend , ndate0, iitend_date ) ! Date of final time step
193	CALL calc_date( nit000, nitbkg_r , ndate0, iitbkg_date ) ! Background time for Jb referenced to ndate0
194	CALL calc_date( nit000, nitdin_r , ndate0, iitdin_date ) ! Background time for DI referenced to ndate0
195	CALL calc_date( nit000, nitiaustr_r, ndate0, iitiaustr_date ) ! IAU start time referenced to ndate0
196	CALL calc_date( nit000, nitiaufin_r, ndate0, iitiaufin_date ) ! IAU end time referenced to ndate0
197	!
198	IF(lwp) THEN
199	WRITE(numout,*)
200	WRITE(numout,*) ' Time steps referenced to current cycle:'
201	WRITE(numout,*) ' iitrst = ', nit000 - 1
202	WRITE(numout,*) ' nit000 = ', nit000
203	WRITE(numout,*) ' nitend = ', nitend
204	WRITE(numout,*) ' nitbkg_r = ', nitbkg_r
205	WRITE(numout,*) ' nitdin_r = ', nitdin_r
206	WRITE(numout,*) ' nitiaustr_r = ', nitiaustr_r
207	WRITE(numout,*) ' nitiaufin_r = ', nitiaufin_r
208	WRITE(numout,*)
209	WRITE(numout,*) ' Dates referenced to current cycle:'
210	WRITE(numout,*) ' ndastp = ', ndastp
211	WRITE(numout,*) ' ndate0 = ', ndate0
212	WRITE(numout,*) ' iitend_date = ', iitend_date
213	WRITE(numout,*) ' iitbkg_date = ', iitbkg_date
214	WRITE(numout,*) ' iitdin_date = ', iitdin_date
215	WRITE(numout,*) ' iitiaustr_date = ', iitiaustr_date
216	WRITE(numout,*) ' iitiaufin_date = ', iitiaufin_date
217	ENDIF
218
219	IF ( nacc /= 0 ) &
220	& CALL ctl_stop( ' nacc /= 0 and key_asminc :', &
221	& ' Assimilation increments have only been implemented', &
222	& ' for synchronous time stepping' )
223
224	IF ( ( ln_asmdin ).AND.( ln_asmiau ) ) &
225	& CALL ctl_stop( ' ln_asmdin and ln_asmiau :', &
226	& ' Choose Direct Initialization OR Incremental Analysis Updating')
227
228	IF ( ( ( .NOT. ln_asmdin ).AND.( .NOT. ln_asmiau ) ) &
229	& .AND.( ( ln_trainc ).OR.( ln_dyninc ).OR.( ln_sshinc ).OR.( ln_seaiceinc ).OR. &
230	& ( ln_sitinc ).OR.( lk_bgcinc ) )) &
231	& CALL ctl_stop( ' One or more of ln_trainc, ln_dyninc, ln_sshinc, ln_seaiceinc,', &
232	& ' ln_sitinc and ln_(bgc-variable)inc is set to .true.', &
233	& ' but ln_asmdin and ln_asmiau are both set to .false. :', &
234	& ' Inconsistent options')
235
236	IF ( ( niaufn /= 0 ).AND.( niaufn /= 1 ) ) &
237	& CALL ctl_stop( ' niaufn /= 0 or niaufn /=1 :', &
238	& ' Type IAU weighting function is invalid')
239
240	IF ( ( .NOT. ln_trainc ).AND.( .NOT. ln_dyninc ).AND.( .NOT. ln_sshinc ).AND.( .NOT. ln_seaiceinc ) &
241	& .AND.( .NOT. ln_sitinc ).AND.( .NOT. lk_bgcinc ) ) &
242	& CALL ctl_warn( ' ln_trainc, ln_dyninc, ln_sshinc, ln_seaiceinc,', &
243	& ' ln_sitinc and ln_(bgc-variable)inc are set to .false. :', &
244	& ' The assimilation increments are not applied')
245
246	IF ( ( ln_asmiau ).AND.( nitiaustr == nitiaufin ) ) &
247	& CALL ctl_stop( ' nitiaustr = nitiaufin :', &
248	& ' IAU interval is of zero length')
249
250	IF ( ( ln_asmiau ).AND.( ( nitiaustr_r < nit000 ).OR.( nitiaufin_r > nitend ) ) ) &
251	& CALL ctl_stop( ' nitiaustr or nitiaufin :', &
252	& ' IAU starting or final time step is outside the cycle interval', &
253	& ' Valid range nit000 to nitend')
254
255	IF ( ( nitbkg_r < nit000 - 1 ).OR.( nitbkg_r > nitend ) ) &
256	& CALL ctl_stop( ' nitbkg :', &
257	& ' Background time step is outside the cycle interval')
258
259	IF ( ( nitdin_r < nit000 - 1 ).OR.( nitdin_r > nitend ) ) &
260	& CALL ctl_stop( ' nitdin :', &
261	& ' Background time step for Direct Initialization is outside', &
262	& ' the cycle interval')
263
264	IF ( nstop > 0 ) RETURN ! if there are any errors then go no further
265
266	!--------------------------------------------------------------------
267	! Initialize the Incremental Analysis Updating weighting function
268	!--------------------------------------------------------------------
269
270	IF ( ln_asmiau ) THEN
271
272	ALLOCATE( wgtiau( icycper ) )
273
274	wgtiau(:) = 0.0
275
276	IF ( niaufn == 0 ) THEN
277
278	!---------------------------------------------------------
279	! Constant IAU forcing
280	!---------------------------------------------------------
281
282	DO jt = 1, iiauper
283	wgtiau(jt+nitiaustr-1) = 1.0 / REAL( iiauper )
284	END DO
285
286	ELSEIF ( niaufn == 1 ) THEN
287
288	!---------------------------------------------------------
289	! Linear hat-like, centred in middle of IAU interval
290	!---------------------------------------------------------
291
292	! Compute the normalization factor
293	znorm = 0.0
294	IF ( MOD( iiauper, 2 ) == 0 ) THEN ! Even number of time steps in IAU interval
295	imid = iiauper / 2
296	DO jt = 1, imid
297	znorm = znorm + REAL( jt )
298	END DO
299	znorm = 2.0 * znorm
300	ELSE ! Odd number of time steps in IAU interval
301	imid = ( iiauper + 1 ) / 2
302	DO jt = 1, imid - 1
303	znorm = znorm + REAL( jt )
304	END DO
305	znorm = 2.0 * znorm + REAL( imid )
306	ENDIF
307	znorm = 1.0 / znorm
308
309	DO jt = 1, imid - 1
310	wgtiau(jt+nitiaustr-1) = REAL( jt ) * znorm
311	END DO
312	DO jt = imid, iiauper
313	wgtiau(jt+nitiaustr-1) = REAL( iiauper - jt + 1 ) * znorm
314	END DO
315
316	ENDIF
317
318	! Test that the integral of the weights over the weighting interval equals 1
319	IF(lwp) THEN
320	WRITE(numout,*)
321	WRITE(numout,*) 'asm_inc_init : IAU weights'
322	WRITE(numout,*) '~~~~~~~~~~~~'
323	WRITE(numout,*) ' time step IAU weight'
324	WRITE(numout,*) ' ========= ====================='
325	ztotwgt = 0.0
326	DO jt = 1, icycper
327	ztotwgt = ztotwgt + wgtiau(jt)
328	WRITE(numout,*) ' ', jt, ' ', wgtiau(jt)
329	END DO
330	WRITE(numout,*) ' ==================================='
331	WRITE(numout,*) ' Time-integrated weight = ', ztotwgt
332	WRITE(numout,*) ' ==================================='
333	ENDIF
334
335	ENDIF
336
337	!--------------------------------------------------------------------
338	! Allocate and initialize the increment arrays
339	!--------------------------------------------------------------------
340
341	IF ( ln_trainc ) THEN
342	ALLOCATE( t_bkginc(jpi,jpj,jpk) )
343	ALLOCATE( s_bkginc(jpi,jpj,jpk) )
344	t_bkginc(:,:,:) = 0.0
345	s_bkginc(:,:,:) = 0.0
346	ENDIF
347	IF ( ln_dyninc ) THEN
348	ALLOCATE( u_bkginc(jpi,jpj,jpk) )
349	ALLOCATE( v_bkginc(jpi,jpj,jpk) )
350	u_bkginc(:,:,:) = 0.0
351	v_bkginc(:,:,:) = 0.0
352	ENDIF
353	IF ( ln_sshinc ) THEN
354	ALLOCATE( ssh_bkginc(jpi,jpj) )
355	ssh_bkginc(:,:) = 0.0
356	ENDIF
357	IF ( ln_seaiceinc ) THEN
358	ALLOCATE( seaice_bkginc(jpi,jpj))
359	seaice_bkginc(:,:) = 0.0
360	ENDIF
361	IF ( ln_sitinc ) THEN
362	ALLOCATE( sit_bkginc(jpi,jpj))
363	sit_bkginc(:,:) = 0.0
364	ENDIF
365	#if defined key_asminc
366	ALLOCATE( ssh_iau(jpi,jpj) )
367	ssh_iau(:,:) = 0.0
368	#endif
369	IF ( ( ln_trainc ).OR.( ln_dyninc ).OR.( ln_sshinc ).OR.( ln_seaiceinc ) &
370	& .OR.( ln_sitinc ).OR.( lk_bgcinc ) ) THEN
371
372	!--------------------------------------------------------------------
373	! Read the increments from file
374	!--------------------------------------------------------------------
375
376	CALL iom_open( c_asminc, inum )
377
378	CALL iom_get( inum, 'time', zdate_inc )
379
380	CALL iom_get( inum, 'z_inc_dateb', z_inc_dateb )
381	CALL iom_get( inum, 'z_inc_datef', z_inc_datef )
382	z_inc_dateb = zdate_inc
383	z_inc_datef = zdate_inc
384
385	IF(lwp) THEN
386	WRITE(numout,*)
387	WRITE(numout,*) 'asm_inc_init : Assimilation increments valid ', &
388	& ' between dates ', NINT( z_inc_dateb ),' and ', &
389	& NINT( z_inc_datef )
390	WRITE(numout,*) '~~~~~~~~~~~~'
391	ENDIF
392
393	IF ( ( NINT( z_inc_dateb ) < ndastp ) &
394	& .OR.( NINT( z_inc_datef ) > iitend_date ) ) &
395	& CALL ctl_warn( ' Validity time of assimilation increments is ', &
396	& ' outside the assimilation interval' )
397
398	IF ( ( ln_asmdin ).AND.( NINT( zdate_inc ) /= iitdin_date ) ) &
399	& CALL ctl_warn( ' Validity time of assimilation increments does ', &
400	& ' not agree with Direct Initialization time' )
401
402	IF ( ln_trainc ) THEN
403	CALL iom_get( inum, jpdom_autoglo, 'bckint', t_bkginc, 1 )
404	CALL iom_get( inum, jpdom_autoglo, 'bckins', s_bkginc, 1 )
405	! Apply the masks
406	t_bkginc(:,:,:) = t_bkginc(:,:,:) * tmask(:,:,:)
407	s_bkginc(:,:,:) = s_bkginc(:,:,:) * tmask(:,:,:)
408	! Set missing increments to 0.0 rather than 1e+20
409	! to allow for differences in masks
410	WHERE( ABS( t_bkginc(:,:,:) ) > 1.0e+10 ) t_bkginc(:,:,:) = 0.0
411	WHERE( ABS( s_bkginc(:,:,:) ) > 1.0e+10 ) s_bkginc(:,:,:) = 0.0
412	ENDIF
413
414	IF ( ln_dyninc ) THEN
415	CALL iom_get( inum, jpdom_autoglo, 'bckinu', u_bkginc, 1 )
416	CALL iom_get( inum, jpdom_autoglo, 'bckinv', v_bkginc, 1 )
417	! Apply the masks
418	u_bkginc(:,:,:) = u_bkginc(:,:,:) * umask(:,:,:)
419	v_bkginc(:,:,:) = v_bkginc(:,:,:) * vmask(:,:,:)
420	! Set missing increments to 0.0 rather than 1e+20
421	! to allow for differences in masks
422	WHERE( ABS( u_bkginc(:,:,:) ) > 1.0e+10 ) u_bkginc(:,:,:) = 0.0
423	WHERE( ABS( v_bkginc(:,:,:) ) > 1.0e+10 ) v_bkginc(:,:,:) = 0.0
424	ENDIF
425
426	IF ( ln_sshinc ) THEN
427	CALL iom_get( inum, jpdom_autoglo, 'bckineta', ssh_bkginc, 1 )
428	! Apply the masks
429	ssh_bkginc(:,:) = ssh_bkginc(:,:) * tmask(:,:,1)
430	! Set missing increments to 0.0 rather than 1e+20
431	! to allow for differences in masks
432	WHERE( ABS( ssh_bkginc(:,:) ) > 1.0e+10 ) ssh_bkginc(:,:) = 0.0
433	ENDIF
434
435	IF ( ln_sitinc ) THEN
436	CALL iom_get( inum, jpdom_autoglo, 'bckinsit', sit_bkginc, 1 )
437	! Apply the masks
438	sit_bkginc(:,:) = sit_bkginc(:,:) * tmask(:,:,1)
439	! Set missing increments to 0.0 rather than 1e+20
440	! to allow for differences in masks
441	WHERE( ABS( sit_bkginc(:,:) ) > 1.0e+10 ) sit_bkginc(:,:) = 0.0
442	ENDIF
443
444	IF ( ln_seaiceinc ) THEN
445	CALL iom_get( inum, jpdom_autoglo, 'bckinseaice', seaice_bkginc, 1 )
446	! Apply the masks
447	seaice_bkginc(:,:) = seaice_bkginc(:,:) * tmask(:,:,1)
448	! Set missing increments to 0.0 rather than 1e+20
449	! to allow for differences in masks
450	WHERE( ABS( seaice_bkginc(:,:) ) > 1.0e+10 ) seaice_bkginc(:,:) = 0.0
451	ENDIF
452
453	CALL iom_close( inum )
454
455	ENDIF
456
457	!-----------------------------------------------------------------------
458	! Apply divergence damping filter
459	!-----------------------------------------------------------------------
460
461	IF ( ln_dyninc .AND. nn_divdmp > 0 ) THEN
462
463	CALL wrk_alloc(jpi,jpj,hdiv)
464
465	DO jt = 1, nn_divdmp
466
467	DO jk = 1, jpkm1
468
469	hdiv(:,:) = 0._wp
470
471	DO jj = 2, jpjm1
472	DO ji = fs_2, fs_jpim1 ! vector opt.
473	hdiv(ji,jj) = &
474	( e2u(ji ,jj ) * fse3u(ji ,jj ,jk) * u_bkginc(ji ,jj ,jk) &
475	- e2u(ji-1,jj ) * fse3u(ji-1,jj ,jk) * u_bkginc(ji-1,jj ,jk) &
476	+ e1v(ji ,jj ) * fse3v(ji ,jj ,jk) * v_bkginc(ji ,jj ,jk) &
477	- e1v(ji ,jj-1) * fse3v(ji ,jj-1,jk) * v_bkginc(ji ,jj-1,jk) ) &
478	/ ( e1t(ji,jj) * e2t(ji,jj) * fse3t(ji,jj,jk) )
479	END DO
480	END DO
481
482	CALL lbc_lnk( hdiv, 'T', 1. ) ! lateral boundary cond. (no sign change)
483
484	DO jj = 2, jpjm1
485	DO ji = fs_2, fs_jpim1 ! vector opt.
486	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) &
487	- e1t(ji ,jj)e2t(ji ,jj) hdiv(ji ,jj) ) &
488	/ e1u(ji,jj) * umask(ji,jj,jk)
489	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) &
490	- e1t(ji,jj )e2t(ji,jj ) hdiv(ji,jj ) ) &
491	/ e2v(ji,jj) * vmask(ji,jj,jk)
492	END DO
493	END DO
494
495	END DO
496
497	END DO
498
499	CALL wrk_dealloc(jpi,jpj,hdiv)
500
501	ENDIF
502
503
504
505	!-----------------------------------------------------------------------
506	! Allocate and initialize the background state arrays
507	!-----------------------------------------------------------------------
508
509	IF ( ln_asmdin ) THEN
510
511	ALLOCATE( t_bkg(jpi,jpj,jpk) )
512	ALLOCATE( s_bkg(jpi,jpj,jpk) )
513	ALLOCATE( u_bkg(jpi,jpj,jpk) )
514	ALLOCATE( v_bkg(jpi,jpj,jpk) )
515	ALLOCATE( ssh_bkg(jpi,jpj) )
516
517	t_bkg(:,:,:) = 0.0
518	s_bkg(:,:,:) = 0.0
519	u_bkg(:,:,:) = 0.0
520	v_bkg(:,:,:) = 0.0
521	ssh_bkg(:,:) = 0.0
522
523	!--------------------------------------------------------------------
524	! Read from file the background state at analysis time
525	!--------------------------------------------------------------------
526
527	CALL iom_open( c_asmdin, inum )
528
529	CALL iom_get( inum, 'rdastp', zdate_bkg )
530
531	IF(lwp) THEN
532	WRITE(numout,*)
533	WRITE(numout,*) 'asm_inc_init : Assimilation background state valid at : ', &
534	& NINT( zdate_bkg )
535	WRITE(numout,*) '~~~~~~~~~~~~'
536	ENDIF
537
538	IF ( NINT( zdate_bkg ) /= iitdin_date ) &
539	& CALL ctl_warn( ' Validity time of assimilation background state does', &
540	& ' not agree with Direct Initialization time' )
541
542	IF ( ln_trainc ) THEN
543	CALL iom_get( inum, jpdom_autoglo, 'tn', t_bkg )
544	CALL iom_get( inum, jpdom_autoglo, 'sn', s_bkg )
545	t_bkg(:,:,:) = t_bkg(:,:,:) * tmask(:,:,:)
546	s_bkg(:,:,:) = s_bkg(:,:,:) * tmask(:,:,:)
547	ENDIF
548
549	IF ( ln_dyninc ) THEN
550	CALL iom_get( inum, jpdom_autoglo, 'un', u_bkg )
551	CALL iom_get( inum, jpdom_autoglo, 'vn', v_bkg )
552	u_bkg(:,:,:) = u_bkg(:,:,:) * umask(:,:,:)
553	v_bkg(:,:,:) = v_bkg(:,:,:) * vmask(:,:,:)
554	ENDIF
555
556	IF ( ln_sshinc ) THEN
557	CALL iom_get( inum, jpdom_autoglo, 'sshn', ssh_bkg )
558	ssh_bkg(:,:) = ssh_bkg(:,:) * tmask(:,:,1)
559	ENDIF
560
561	CALL iom_close( inum )
562
563	ENDIF
564	!
565	END SUBROUTINE asm_inc_init
566
567
568	SUBROUTINE calc_date( kit000, kt, kdate0, kdate )
569	!!----------------------------------------------------------------------
570	!! * ROUTINE calc_date *
571	!!
572	!! ** Purpose : Compute the calendar date YYYYMMDD at a given time step.
573	!!
574	!! ** Method : Compute the calendar date YYYYMMDD at a given time step.
575	!!
576	!! ** Action :
577	!!----------------------------------------------------------------------
578	INTEGER, INTENT(IN) :: kit000 ! Initial time step
579	INTEGER, INTENT(IN) :: kt ! Current time step referenced to kit000
580	INTEGER, INTENT(IN) :: kdate0 ! Initial date
581	INTEGER, INTENT(OUT) :: kdate ! Current date reference to kdate0
582	!
583	INTEGER :: iyea0 ! Initial year
584	INTEGER :: imon0 ! Initial month
585	INTEGER :: iday0 ! Initial day
586	INTEGER :: iyea ! Current year
587	INTEGER :: imon ! Current month
588	INTEGER :: iday ! Current day
589	INTEGER :: idaystp ! Number of days between initial and current date
590	INTEGER :: idaycnt ! Day counter
591
592	INTEGER, DIMENSION(12) :: imonth_len !: length in days of the months of the current year
593
594	!-----------------------------------------------------------------------
595	! Compute the calendar date YYYYMMDD
596	!-----------------------------------------------------------------------
597
598	! Initial date
599	iyea0 = kdate0 / 10000
600	imon0 = ( kdate0 - ( iyea0 * 10000 ) ) / 100
601	iday0 = kdate0 - ( iyea0 * 10000 ) - ( imon0 * 100 )
602
603	! Check that kt >= kit000 - 1
604	IF ( kt < kit000 - 1 ) CALL ctl_stop( ' kt must be >= kit000 - 1')
605
606	! If kt = kit000 - 1 then set the date to the restart date
607	IF ( kt == kit000 - 1 ) THEN
608
609	kdate = ndastp
610	RETURN
611
612	ENDIF
613
614	! Compute the number of days from the initial date
615	idaystp = INT( REAL( kt - kit000 ) * rdt / 86400. )
616
617	iday = iday0
618	imon = imon0
619	iyea = iyea0
620	idaycnt = 0
621
622	CALL calc_month_len( iyea, imonth_len )
623
624	DO WHILE ( idaycnt < idaystp )
625	iday = iday + 1
626	IF ( iday > imonth_len(imon) ) THEN
627	iday = 1
628	imon = imon + 1
629	ENDIF
630	IF ( imon > 12 ) THEN
631	imon = 1
632	iyea = iyea + 1
633	CALL calc_month_len( iyea, imonth_len ) ! update month lengths
634	ENDIF
635	idaycnt = idaycnt + 1
636	END DO
637	!
638	kdate = iyea * 10000 + imon * 100 + iday
639	!
640	END SUBROUTINE
641
642
643	SUBROUTINE calc_month_len( iyear, imonth_len )
644	!!----------------------------------------------------------------------
645	!! * ROUTINE calc_month_len *
646	!!
647	!! ** Purpose : Compute the number of days in a months given a year.
648	!!
649	!! ** Method :
650	!!----------------------------------------------------------------------
651	INTEGER, DIMENSION(12) :: imonth_len !: length in days of the months of the current year
652	INTEGER :: iyear !: year
653	!!----------------------------------------------------------------------
654	!
655	! length of the month of the current year (from nleapy, read in namelist)
656	IF ( nleapy < 2 ) THEN
657	imonth_len(:) = (/ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 /)
658	IF ( nleapy == 1 ) THEN ! we are using calendar with leap years
659	IF ( MOD(iyear, 4) == 0 .AND. ( MOD(iyear, 400) == 0 .OR. MOD(iyear, 100) /= 0 ) ) THEN
660	imonth_len(2) = 29
661	ENDIF
662	ENDIF
663	ELSE
664	imonth_len(:) = nleapy ! all months with nleapy days per year
665	ENDIF
666	!
667	END SUBROUTINE
668
669
670	SUBROUTINE tra_asm_inc( kt )
671	!!----------------------------------------------------------------------
672	!! * ROUTINE tra_asm_inc *
673	!!
674	!! ** Purpose : Apply the tracer (T and S) assimilation increments
675	!!
676	!! ** Method : Direct initialization or Incremental Analysis Updating
677	!!
678	!! ** Action :
679	!!----------------------------------------------------------------------
680	INTEGER, INTENT(IN) :: kt ! Current time step
681	!
682	INTEGER :: ji,jj,jk
683	INTEGER :: it
684	REAL(wp) :: zincwgt ! IAU weight for current time step
685	REAL (wp), DIMENSION(jpi,jpj,jpk) :: fzptnz ! 3d freezing point values
686	!!----------------------------------------------------------------------
687
688	! freezing point calculation taken from oc_fz_pt (but calculated for all depths)
689	! used to prevent the applied increments taking the temperature below the local freezing point
690
691	DO jk = 1, jpkm1
692	fzptnz(:,:,jk) = eos_fzp( tsn(:,:,jk,jp_sal), fsdept(:,:,jk) )
693	END DO
694
695	IF ( ln_asmiau ) THEN
696
697	!--------------------------------------------------------------------
698	! Incremental Analysis Updating
699	!--------------------------------------------------------------------
700
701	IF ( ( kt >= nitiaustr_r ).AND.( kt <= nitiaufin_r ) ) THEN
702
703	it = kt - nit000 + 1
704	zincwgt = wgtiau(it) / rdt ! IAU weight for the current time step
705
706	IF(lwp) THEN
707	WRITE(numout,*)
708	WRITE(numout,*) 'tra_asm_inc : Tracer IAU at time step = ', kt,' with IAU weight = ', wgtiau(it)
709	WRITE(numout,*) '~~~~~~~~~~~~'
710	ENDIF
711
712	! Update the tracer tendencies
713	DO jk = 1, jpkm1
714	IF (ln_temnofreeze) THEN
715	! Do not apply negative increments if the temperature will fall below freezing
716	WHERE(t_bkginc(:,:,jk) > 0.0_wp .OR. &
717	& tsn(:,:,jk,jp_tem) + tsa(:,:,jk,jp_tem) + t_bkginc(:,:,jk) * wgtiau(it) > fzptnz(:,:,jk) )
718	tsa(:,:,jk,jp_tem) = tsa(:,:,jk,jp_tem) + t_bkginc(:,:,jk) * zincwgt
719	END WHERE
720	ELSE
721	tsa(:,:,jk,jp_tem) = tsa(:,:,jk,jp_tem) + t_bkginc(:,:,jk) * zincwgt
722	ENDIF
723	IF (ln_salfix) THEN
724	! Do not apply negative increments if the salinity will fall below a specified
725	! minimum value salfixmin
726	WHERE(s_bkginc(:,:,jk) > 0.0_wp .OR. &
727	& tsn(:,:,jk,jp_sal) + tsa(:,:,jk,jp_sal) + s_bkginc(:,:,jk) * wgtiau(it) > salfixmin )
728	tsa(:,:,jk,jp_sal) = tsa(:,:,jk,jp_sal) + s_bkginc(:,:,jk) * zincwgt
729	END WHERE
730	ELSE
731	tsa(:,:,jk,jp_sal) = tsa(:,:,jk,jp_sal) + s_bkginc(:,:,jk) * zincwgt
732	ENDIF
733	END DO
734
735	ENDIF
736
737	IF ( kt == nitiaufin_r + 1 ) THEN ! For bias crcn to work
738	DEALLOCATE( t_bkginc )
739	DEALLOCATE( s_bkginc )
740	ENDIF
741
742
743	ELSEIF ( ln_asmdin ) THEN
744
745	!--------------------------------------------------------------------
746	! Direct Initialization
747	!--------------------------------------------------------------------
748
749	IF ( kt == nitdin_r ) THEN
750
751	neuler = 0 ! Force Euler forward step
752
753	! Initialize the now fields with the background + increment
754	IF (ln_temnofreeze) THEN
755	! Do not apply negative increments if the temperature will fall below freezing
756	WHERE( t_bkginc(:,:,:) > 0.0_wp .OR. tsn(:,:,:,jp_tem) + t_bkginc(:,:,:) > fzptnz(:,:,:) )
757	tsn(:,:,:,jp_tem) = t_bkg(:,:,:) + t_bkginc(:,:,:)
758	END WHERE
759	ELSE
760	tsn(:,:,:,jp_tem) = t_bkg(:,:,:) + t_bkginc(:,:,:)
761	ENDIF
762	IF (ln_salfix) THEN
763	! Do not apply negative increments if the salinity will fall below a specified
764	! minimum value salfixmin
765	WHERE( s_bkginc(:,:,:) > 0.0_wp .OR. tsn(:,:,:,jp_sal) + s_bkginc(:,:,:) > salfixmin )
766	tsn(:,:,:,jp_sal) = s_bkg(:,:,:) + s_bkginc(:,:,:)
767	END WHERE
768	ELSE
769	tsn(:,:,:,jp_sal) = s_bkg(:,:,:) + s_bkginc(:,:,:)
770	ENDIF
771
772	tsb(:,:,:,:) = tsn(:,:,:,:) ! Update before fields
773
774	CALL eos( tsb, rhd, rhop, gdept_0(:,:,:) ) ! Before potential and in situ densities
775	!!gm fabien
776	! CALL eos( tsb, rhd, rhop ) ! Before potential and in situ densities
777	!!gm
778
779
780	IF( ln_zps .AND. .NOT. lk_c1d .AND. .NOT. ln_isfcav) &
781	& CALL zps_hde ( kt, jpts, tsb, gtsu, gtsv, & ! Partial steps: before horizontal gradient
782	& rhd, gru , grv ) ! of t, s, rd at the last ocean level
783	IF( ln_zps .AND. .NOT. lk_c1d .AND. ln_isfcav) &
784	& CALL zps_hde_isf( nit000, jpts, tsb, gtsu, gtsv, & ! Partial steps for top cell (ISF)
785	& rhd, gru , grv , aru , arv , gzu , gzv , ge3ru , ge3rv , &
786	& gtui, gtvi, grui, grvi, arui, arvi, gzui, gzvi, ge3rui, ge3rvi ) ! of t, s, rd at the last ocean level
787
788	#if defined key_zdfkpp
789	CALL eos( tsn, rhd, fsdept_n(:,:,:) ) ! Compute rhd
790	!!gm fabien CALL eos( tsn, rhd ) ! Compute rhd
791	#endif
792
793	DEALLOCATE( t_bkginc )
794	DEALLOCATE( s_bkginc )
795	DEALLOCATE( t_bkg )
796	DEALLOCATE( s_bkg )
797	ENDIF
798	!
799	ENDIF
800	! Perhaps the following call should be in step
801	IF ( ln_seaiceinc ) CALL seaice_asm_inc ( kt ) ! apply sea ice concentration increment
802	IF ( ln_sitinc ) CALL sit_asm_inc ( kt ) ! apply sea ice thickness increment
803	!
804	END SUBROUTINE tra_asm_inc
805
806
807	SUBROUTINE dyn_asm_inc( kt )
808	!!----------------------------------------------------------------------
809	!! * ROUTINE dyn_asm_inc *
810	!!
811	!! ** Purpose : Apply the dynamics (u and v) assimilation increments.
812	!!
813	!! ** Method : Direct initialization or Incremental Analysis Updating.
814	!!
815	!! ** Action :
816	!!----------------------------------------------------------------------
817	INTEGER, INTENT(IN) :: kt ! Current time step
818	!
819	INTEGER :: jk
820	INTEGER :: it
821	REAL(wp) :: zincwgt ! IAU weight for current time step
822	!!----------------------------------------------------------------------
823
824	IF ( ln_asmiau ) THEN
825
826	!--------------------------------------------------------------------
827	! Incremental Analysis Updating
828	!--------------------------------------------------------------------
829
830	IF ( ( kt >= nitiaustr_r ).AND.( kt <= nitiaufin_r ) ) THEN
831
832	it = kt - nit000 + 1
833	zincwgt = wgtiau(it) / rdt ! IAU weight for the current time step
834
835	IF(lwp) THEN
836	WRITE(numout,*)
837	WRITE(numout,*) 'dyn_asm_inc : Dynamics IAU at time step = ', &
838	& kt,' with IAU weight = ', wgtiau(it)
839	WRITE(numout,*) '~~~~~~~~~~~~'
840	ENDIF
841
842	! Update the dynamic tendencies
843	DO jk = 1, jpkm1
844	ua(:,:,jk) = ua(:,:,jk) + u_bkginc(:,:,jk) * zincwgt
845	va(:,:,jk) = va(:,:,jk) + v_bkginc(:,:,jk) * zincwgt
846	END DO
847
848	IF ( kt == nitiaufin_r ) THEN
849	DEALLOCATE( u_bkginc )
850	DEALLOCATE( v_bkginc )
851	ENDIF
852
853	ENDIF
854
855	ELSEIF ( ln_asmdin ) THEN
856
857	!--------------------------------------------------------------------
858	! Direct Initialization
859	!--------------------------------------------------------------------
860
861	IF ( kt == nitdin_r ) THEN
862
863	neuler = 0 ! Force Euler forward step
864
865	! Initialize the now fields with the background + increment
866	un(:,:,:) = u_bkg(:,:,:) + u_bkginc(:,:,:)
867	vn(:,:,:) = v_bkg(:,:,:) + v_bkginc(:,:,:)
868
869	ub(:,:,:) = un(:,:,:) ! Update before fields
870	vb(:,:,:) = vn(:,:,:)
871
872	DEALLOCATE( u_bkg )
873	DEALLOCATE( v_bkg )
874	DEALLOCATE( u_bkginc )
875	DEALLOCATE( v_bkginc )
876	ENDIF
877	!
878	ENDIF
879	!
880	END SUBROUTINE dyn_asm_inc
881
882
883	SUBROUTINE ssh_asm_inc( kt )
884	!!----------------------------------------------------------------------
885	!! * ROUTINE ssh_asm_inc *
886	!!
887	!! ** Purpose : Apply the sea surface height assimilation increment.
888	!!
889	!! ** Method : Direct initialization or Incremental Analysis Updating.
890	!!
891	!! ** Action :
892	!!----------------------------------------------------------------------
893	INTEGER, INTENT(IN) :: kt ! Current time step
894	!
895	INTEGER :: it
896	INTEGER :: jk
897	REAL(wp) :: zincwgt ! IAU weight for current time step
898	!!----------------------------------------------------------------------
899
900	IF ( ln_asmiau ) THEN
901
902	!--------------------------------------------------------------------
903	! Incremental Analysis Updating
904	!--------------------------------------------------------------------
905
906	IF ( ( kt >= nitiaustr_r ).AND.( kt <= nitiaufin_r ) ) THEN
907
908	it = kt - nit000 + 1
909	zincwgt = wgtiau(it) / rdt ! IAU weight for the current time step
910
911	IF(lwp) THEN
912	WRITE(numout,*)
913	WRITE(numout,*) 'ssh_asm_inc : SSH IAU at time step = ', &
914	& kt,' with IAU weight = ', wgtiau(it)
915	WRITE(numout,*) '~~~~~~~~~~~~'
916	ENDIF
917
918	! Save the tendency associated with the IAU weighted SSH increment
919	! (applied in dynspg.*)
920	#if defined key_asminc
921	ssh_iau(:,:) = ssh_bkginc(:,:) * zincwgt
922	#endif
923	IF ( kt == nitiaufin_r ) THEN
924	DEALLOCATE( ssh_bkginc )
925	ENDIF
926
927	ENDIF
928
929	ELSEIF ( ln_asmdin ) THEN
930
931	!--------------------------------------------------------------------
932	! Direct Initialization
933	!--------------------------------------------------------------------
934
935	IF ( kt == nitdin_r ) THEN
936
937	neuler = 0 ! Force Euler forward step
938
939	! Initialize the now fields the background + increment
940	sshn(:,:) = ssh_bkg(:,:) + ssh_bkginc(:,:)
941
942	! Update before fields
943	sshb(:,:) = sshn(:,:)
944
945	IF( lk_vvl ) THEN
946	DO jk = 1, jpk
947	fse3t_b(:,:,jk) = fse3t_n(:,:,jk)
948	END DO
949	ENDIF
950
951	DEALLOCATE( ssh_bkg )
952	DEALLOCATE( ssh_bkginc )
953
954	ENDIF
955	!
956	ENDIF
957	!
958	END SUBROUTINE ssh_asm_inc
959
960	SUBROUTINE sit_asm_inc( kt, kindic )
961	!!----------------------------------------------------------------------
962	!! * ROUTINE sit_asm_inc *
963	!!
964	!! ** Purpose : Apply the sea ice thickness assimilation increment.
965	!!
966	!! ** Method : Direct initialization or Incremental Analysis Updating.
967	!!
968	!! ** Action :
969	!!
970	!!----------------------------------------------------------------------
971	IMPLICIT NONE
972	!
973	INTEGER, INTENT(in) :: kt ! Current time step
974	INTEGER, INTENT(in), OPTIONAL :: kindic ! flag for disabling the deallocation
975	!
976	INTEGER :: it
977	REAL(wp) :: zincwgt ! IAU weight for current time step
978	!!----------------------------------------------------------------------
979
980	IF ( ln_asmiau ) THEN
981
982	!--------------------------------------------------------------------
983	! Incremental Analysis Updating
984	!--------------------------------------------------------------------
985
986	IF ( ( kt >= nitiaustr_r ).AND.( kt <= nitiaufin_r ) ) THEN
987
988	it = kt - nit000 + 1
989	zincwgt = wgtiau(it) ! IAU weight for the current time step
990	! note this is not a tendency so should not be divided by rdt (as with the tracer and other increments)
991	! EF: Actually CICE is expecting a tendency so is divided by rdt below
992
993	IF(lwp) THEN
994	WRITE(numout,*)
995	WRITE(numout,*) 'sit_asm_inc : sea ice thick IAU at time step = ', &
996	& kt,' with IAU weight = ', wgtiau(it)
997	WRITE(numout,*) '~~~~~~~~~~~~'
998	ENDIF
999
1000	#if defined key_cice && defined key_asminc
1001	! Sea-ice thickness : CICE case. Pass ice thickness increment tendency into CICE
1002	ndsit_da(:,:) = sit_bkginc(:,:) * zincwgt / rdt
1003	#endif
1004
1005	IF ( kt == nitiaufin_r ) THEN
1006	DEALLOCATE( sit_bkginc )
1007	ENDIF
1008
1009	ELSE
1010
1011	#if defined key_cice && defined key_asminc
1012	! Sea-ice thickness : CICE case. Zero ice increment tendency into CICE
1013	ndsit_da(:,:) = 0.0_wp
1014	#endif
1015
1016	ENDIF
1017
1018	ELSEIF ( ln_asmdin ) THEN
1019
1020	!--------------------------------------------------------------------
1021	! Direct Initialization
1022	!--------------------------------------------------------------------
1023
1024	IF ( kt == nitdin_r ) THEN
1025
1026	neuler = 0 ! Force Euler forward step
1027
1028	#if defined key_cice && defined key_asminc
1029	! Sea-ice thickness : CICE case. Pass ice thickness increment tendency into CICE
1030	ndsit_da(:,:) = sit_bkginc(:,:) / rdt
1031	#endif
1032	IF ( .NOT. PRESENT(kindic) ) THEN
1033	DEALLOCATE( sit_bkginc )
1034	END IF
1035
1036	ELSE
1037
1038	#if defined key_cice && defined key_asminc
1039	! Sea-ice thicnkness : CICE case. Zero ice thickness increment tendency into CICE
1040	ndsit_da(:,:) = 0.0_wp
1041	#endif
1042
1043	ENDIF
1044
1045	ENDIF
1046
1047	END SUBROUTINE sit_asm_inc
1048
1049	SUBROUTINE seaice_asm_inc( kt, kindic )
1050	!!----------------------------------------------------------------------
1051	!! * ROUTINE seaice_asm_inc *
1052	!!
1053	!! ** Purpose : Apply the sea ice concentration assimilation increment.
1054	!!
1055	!! ** Method : Direct initialization or Incremental Analysis Updating.
1056	!!
1057	!! ** Action :
1058	!!
1059	!!----------------------------------------------------------------------
1060	IMPLICIT NONE
1061	!
1062	INTEGER, INTENT(in) :: kt ! Current time step
1063	INTEGER, INTENT(in), OPTIONAL :: kindic ! flag for disabling the deallocation
1064	!
1065	INTEGER :: it
1066	REAL(wp) :: zincwgt ! IAU weight for current time step
1067	#if defined key_lim2
1068	REAL(wp), DIMENSION(jpi,jpj) :: zofrld, zohicif, zseaicendg, zhicifinc ! LIM
1069	REAL(wp) :: zhicifmin = 0.5_wp ! ice minimum depth in metres
1070	#endif
1071	!!----------------------------------------------------------------------
1072
1073	IF ( ln_asmiau ) THEN
1074
1075	!--------------------------------------------------------------------
1076	! Incremental Analysis Updating
1077	!--------------------------------------------------------------------
1078
1079	IF ( ( kt >= nitiaustr_r ).AND.( kt <= nitiaufin_r ) ) THEN
1080
1081	it = kt - nit000 + 1
1082	zincwgt = wgtiau(it) ! IAU weight for the current time step
1083	! note this is not a tendency so should not be divided by rdt (as with the tracer and other increments)
1084
1085	IF(lwp) THEN
1086	WRITE(numout,*)
1087	WRITE(numout,*) 'seaice_asm_inc : sea ice conc IAU at time step = ', &
1088	& kt,' with IAU weight = ', wgtiau(it)
1089	WRITE(numout,*) '~~~~~~~~~~~~'
1090	ENDIF
1091
1092	! Sea-ice : LIM-3 case (to add)
1093
1094	#if defined key_lim2
1095	! Sea-ice : LIM-2 case
1096	zofrld (:,:) = frld(:,:)
1097	zohicif(:,:) = hicif(:,:)
1098	!
1099	frld = MIN( MAX( frld (:,:) - seaice_bkginc(:,:) * zincwgt, 0.0_wp), 1.0_wp)
1100	pfrld = MIN( MAX( pfrld(:,:) - seaice_bkginc(:,:) * zincwgt, 0.0_wp), 1.0_wp)
1101	fr_i(:,:) = 1.0_wp - frld(:,:) ! adjust ice fraction
1102	!
1103	zseaicendg(:,:) = zofrld(:,:) - frld(:,:) ! find out actual sea ice nudge applied
1104	!
1105	! Nudge sea ice depth to bring it up to a required minimum depth
1106	WHERE( zseaicendg(:,:) > 0.0_wp .AND. hicif(:,:) < zhicifmin )
1107	zhicifinc(:,:) = (zhicifmin - hicif(:,:)) * zincwgt
1108	ELSEWHERE
1109	zhicifinc(:,:) = 0.0_wp
1110	END WHERE
1111	!
1112	! nudge ice depth
1113	hicif (:,:) = hicif (:,:) + zhicifinc(:,:)
1114	phicif(:,:) = phicif(:,:) + zhicifinc(:,:)
1115	!
1116	! seaice salinity balancing (to add)
1117	#endif
1118
1119	#if defined key_cice && defined key_asminc
1120	! Sea-ice : CICE case. Pass ice increment tendency into CICE
1121	ndaice_da(:,:) = seaice_bkginc(:,:) * zincwgt / rdt
1122	#endif
1123
1124	IF ( kt == nitiaufin_r ) THEN
1125	DEALLOCATE( seaice_bkginc )
1126	ENDIF
1127
1128	ELSE
1129
1130	#if defined key_cice && defined key_asminc
1131	! Sea-ice : CICE case. Zero ice increment tendency into CICE
1132	ndaice_da(:,:) = 0.0_wp
1133	#endif
1134
1135	ENDIF
1136
1137	ELSEIF ( ln_asmdin ) THEN
1138
1139	!--------------------------------------------------------------------
1140	! Direct Initialization
1141	!--------------------------------------------------------------------
1142
1143	IF ( kt == nitdin_r ) THEN
1144
1145	neuler = 0 ! Force Euler forward step
1146
1147	! Sea-ice : LIM-3 case (to add)
1148
1149	#if defined key_lim2
1150	! Sea-ice : LIM-2 case.
1151	zofrld(:,:)=frld(:,:)
1152	zohicif(:,:)=hicif(:,:)
1153	!
1154	! Initialize the now fields the background + increment
1155	frld (:,:) = MIN( MAX( frld(:,:) - seaice_bkginc(:,:), 0.0_wp), 1.0_wp)
1156	pfrld(:,:) = frld(:,:)
1157	fr_i (:,:) = 1.0_wp - frld(:,:) ! adjust ice fraction
1158	zseaicendg(:,:) = zofrld(:,:) - frld(:,:) ! find out actual sea ice nudge applied
1159	!
1160	! Nudge sea ice depth to bring it up to a required minimum depth
1161	WHERE( zseaicendg(:,:) > 0.0_wp .AND. hicif(:,:) < zhicifmin )
1162	zhicifinc(:,:) = (zhicifmin - hicif(:,:)) * zincwgt
1163	ELSEWHERE
1164	zhicifinc(:,:) = 0.0_wp
1165	END WHERE
1166	!
1167	! nudge ice depth
1168	hicif (:,:) = hicif (:,:) + zhicifinc(:,:)
1169	phicif(:,:) = phicif(:,:)
1170	!
1171	! seaice salinity balancing (to add)
1172	#endif
1173
1174	#if defined key_cice && defined key_asminc
1175	! Sea-ice : CICE case. Pass ice increment tendency into CICE
1176	ndaice_da(:,:) = seaice_bkginc(:,:) / rdt
1177	#endif
1178	IF ( .NOT. PRESENT(kindic) ) THEN
1179	DEALLOCATE( seaice_bkginc )
1180	END IF
1181
1182	ELSE
1183
1184	#if defined key_cice && defined key_asminc
1185	! Sea-ice : CICE case. Zero ice increment tendency into CICE
1186	ndaice_da(:,:) = 0.0_wp
1187	#endif
1188
1189	ENDIF
1190
1191	!#if defined defined key_lim2 \|\| defined key_cice
1192	!
1193	! IF (ln_seaicebal ) THEN
1194	! !! balancing salinity increments
1195	! !! simple case from limflx.F90 (doesn't include a mass flux)
1196	! !! assumption is that as ice concentration is reduced or increased
1197	! !! the snow and ice depths remain constant
1198	! !! note that snow is being created where ice concentration is being increased
1199	! !! - could be more sophisticated and
1200	! !! not do this (but would need to alter h_snow)
1201	!
1202	! usave(:,:,:)=sb(:,:,:) ! use array as a temporary store
1203	!
1204	! DO jj = 1, jpj
1205	! DO ji = 1, jpi
1206	! ! calculate change in ice and snow mass per unit area
1207	! ! positive values imply adding salt to the ocean (results from ice formation)
1208	! ! fwf : ice formation and melting
1209	!
1210	! zfons = ( -nfresh_da(ji,jj)soce + nfsalt_da(ji,jj) )rdt
1211	!
1212	! ! change salinity down to mixed layer depth
1213	! mld=hmld_kara(ji,jj)
1214	!
1215	! ! prevent small mld
1216	! ! less than 10m can cause salinity instability
1217	! IF (mld < 10) mld=10
1218	!
1219	! ! set to bottom of a level
1220	! DO jk = jpk-1, 2, -1
1221	! IF ((mld > gdepw(ji,jj,jk)) .and. (mld < gdepw(ji,jj,jk+1))) THEN
1222	! mld=gdepw(ji,jj,jk+1)
1223	! jkmax=jk
1224	! ENDIF
1225	! ENDDO
1226	!
1227	! ! avoid applying salinity balancing in shallow water or on land
1228	! !
1229	!
1230	! ! dsal_ocn (psu kg m^-2) / (kg m^-3 * m)
1231	!
1232	! dsal_ocn=0.0_wp
1233	! sal_thresh=5.0_wp ! minimum salinity threshold for salinity balancing
1234	!
1235	! if (tmask(ji,jj,1) > 0 .AND. tmask(ji,jj,jkmax) > 0 ) &
1236	! dsal_ocn = zfons / (rhop(ji,jj,1) * mld)
1237	!
1238	! ! put increments in for levels in the mixed layer
1239	! ! but prevent salinity below a threshold value
1240	!
1241	! DO jk = 1, jkmax
1242	!
1243	! IF (dsal_ocn > 0.0_wp .or. sb(ji,jj,jk)+dsal_ocn > sal_thresh) THEN
1244	! sb(ji,jj,jk) = sb(ji,jj,jk) + dsal_ocn
1245	! sn(ji,jj,jk) = sn(ji,jj,jk) + dsal_ocn
1246	! ENDIF
1247	!
1248	! ENDDO
1249	!
1250	! ! ! salt exchanges at the ice/ocean interface
1251	! ! zpmess = zfons / rdt_ice ! rdt_ice is ice timestep
1252	! !
1253	! !! Adjust fsalt. A +ve fsalt means adding salt to ocean
1254	! !! fsalt(ji,jj) = fsalt(ji,jj) + zpmess ! adjust fsalt
1255	! !!
1256	! !! emps(ji,jj) = emps(ji,jj) + zpmess ! or adjust emps (see icestp1d)
1257	! !! ! E-P (kg m-2 s-2)
1258	! ! emp(ji,jj) = emp(ji,jj) + zpmess ! E-P (kg m-2 s-2)
1259	! ENDDO !ji
1260	! ENDDO !jj!
1261	!
1262	! ENDIF !ln_seaicebal
1263	!
1264	!#endif
1265
1266	ENDIF
1267
1268	END SUBROUTINE seaice_asm_inc
1269
1270	!!======================================================================
1271	END MODULE asminc

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