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source: branches/2012/dev_MERGE_2012/NEMOGCM/NEMO/OPA_SRC/ASM/asminc.F90 @ 3764

Last change on this file since 3764 was 3764, checked in by smasson, 11 years ago
dev_MERGE_2012: report bugfixes done in the trunk from r3555 to r3763 into dev_MERGE_2012
Property svn:keywords set to `Id`
File size: 48.5 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 seaice increment
24	!!----------------------------------------------------------------------
25	USE wrk_nemo ! Memory Allocation
26	USE par_oce ! Ocean space and time domain variables
27	USE dom_oce ! Ocean space and time domain
28	USE oce ! Dynamics and active tracers defined in memory
29	USE ldfdyn_oce ! ocean dynamics: lateral physics
30	USE eosbn2 ! Equation of state - in situ and potential density
31	USE zpshde ! Partial step : Horizontal Derivative
32	USE iom ! Library to read input files
33	USE asmpar ! Parameters for the assmilation interface
34	USE c1d ! 1D initialization
35	USE in_out_manager ! I/O manager
36	USE lib_mpp ! MPP library
37	#if defined key_lim3
38	USE ice ! LIM3
39	#endif
40	#if defined key_lim2
41	USE ice_2 ! LIM2
42	#endif
43	USE sbc_oce ! Surface boundary condition variables.
44	USE domvvl
45
46	IMPLICIT NONE
47	PRIVATE
48
49	PUBLIC asm_inc_init !: Initialize the increment arrays and IAU weights
50	PUBLIC calc_date !: Compute the calendar date YYYYMMDD on a given step
51	PUBLIC tra_asm_inc !: Apply the tracer (T and S) increments
52	PUBLIC dyn_asm_inc !: Apply the dynamic (u and v) increments
53	PUBLIC ssh_asm_inc !: Apply the SSH increment
54	PUBLIC seaice_asm_inc !: Apply the seaice increment
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_asmiau = .FALSE. !: No applying forcing with an assimilation increment
63	LOGICAL, PUBLIC :: ln_asmdin = .FALSE. !: No direct initialization
64	LOGICAL, PUBLIC :: ln_trainc = .FALSE. !: No tracer (T and S) assimilation increments
65	LOGICAL, PUBLIC :: ln_dyninc = .FALSE. !: No dynamics (u and v) assimilation increments
66	LOGICAL, PUBLIC :: ln_sshinc = .FALSE. !: No sea surface height assimilation increment
67	LOGICAL, PUBLIC :: ln_seaiceinc = .FALSE. !: No sea ice concentration increment
68	LOGICAL, PUBLIC :: ln_salfix = .FALSE. !: Apply minimum salinity check
69	LOGICAL, PUBLIC :: ln_temnofreeze = .FALSE. !: Don't allow the temperature to drop below freezing
70	INTEGER, PUBLIC :: nn_divdmp = 0 !: Apply divergence damping filter nn_divdmp times
71
72	REAL(wp), PUBLIC, DIMENSION(:,:,:), ALLOCATABLE :: t_bkg , s_bkg !: Background temperature and salinity
73	REAL(wp), PUBLIC, DIMENSION(:,:,:), ALLOCATABLE :: u_bkg , v_bkg !: Background u- & v- velocity components
74	REAL(wp), PUBLIC, DIMENSION(:,:,:), ALLOCATABLE :: t_bkginc, s_bkginc !: Increment to the background T & S
75	REAL(wp), PUBLIC, DIMENSION(:,:,:), ALLOCATABLE :: u_bkginc, v_bkginc !: Increment to the u- & v-components
76	REAL(wp), PUBLIC, DIMENSION(:) , ALLOCATABLE :: wgtiau !: IAU weights for each time step
77	#if defined key_asminc
78	REAL(wp), PUBLIC, DIMENSION(:,:), ALLOCATABLE :: ssh_iau !: IAU-weighted sea surface height increment
79	#endif
80	! !!! time steps relative to the cycle interval [0,nitend-nit000-1]
81	INTEGER , PUBLIC :: nitbkg !: Time step of the background state used in the Jb term
82	INTEGER , PUBLIC :: nitdin !: Time step of the background state for direct initialization
83	INTEGER , PUBLIC :: nitiaustr !: Time step of the start of the IAU interval
84	INTEGER , PUBLIC :: nitiaufin !: Time step of the end of the IAU interval
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)
89
90	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: ssh_bkg, ssh_bkginc ! Background sea surface height and its increment
91	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: seaice_bkginc ! Increment to the background sea ice conc
92
93	!! * Substitutions
94	# include "domzgr_substitute.h90"
95	# include "ldfdyn_substitute.h90"
96	# include "vectopt_loop_substitute.h90"
97
98	!!----------------------------------------------------------------------
99	!! NEMO/OPA 3.3 , NEMO Consortium (2010)
100	!! $Id$
101	!! Software governed by the CeCILL licence (NEMOGCM/NEMO_CeCILL.txt)
102	!!----------------------------------------------------------------------
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	!!----------------------------------------------------------------------
115	!!
116	!!
117	INTEGER :: ji,jj,jk
118	INTEGER :: jt
119	INTEGER :: imid
120	INTEGER :: inum
121	INTEGER :: iiauper ! Number of time steps in the IAU period
122	INTEGER :: icycper ! Number of time steps in the cycle
123	INTEGER :: iitend_date ! Date YYYYMMDD of final time step
124	INTEGER :: iitbkg_date ! Date YYYYMMDD of background time step for Jb term
125	INTEGER :: iitdin_date ! Date YYYYMMDD of background time step for DI
126	INTEGER :: iitiaustr_date ! Date YYYYMMDD of IAU interval start time step
127	INTEGER :: iitiaufin_date ! Date YYYYMMDD of IAU interval final time step
128
129	REAL(wp) :: znorm ! Normalization factor for IAU weights
130	REAL(wp) :: ztotwgt ! Value of time-integrated IAU weights
131	! (should be equal to one)
132	REAL(wp) :: z_inc_dateb ! Start date of interval on which increment is valid
133	REAL(wp) :: z_inc_datef ! End date of interval on which increment is valid
134	REAL(wp) :: zdate_bkg ! Date in background state file for DI
135	REAL(wp) :: zdate_inc ! Time axis in increments file
136
137	REAL(wp), POINTER, DIMENSION(:,:) :: hdiv
138	!!
139	NAMELIST/nam_asminc/ ln_bkgwri, &
140	& ln_trainc, ln_dyninc, ln_sshinc, &
141	& ln_asmdin, ln_asmiau, &
142	& nitbkg, nitdin, nitiaustr, nitiaufin, niaufn, &
143	& ln_salfix, salfixmin, &
144	& nn_divdmp
145	!!----------------------------------------------------------------------
146
147	!-----------------------------------------------------------------------
148	! Read Namelist nam_asminc : assimilation increment interface
149	!-----------------------------------------------------------------------
150
151	! Set default values
152	ln_bkgwri = .FALSE.
153	ln_trainc = .FALSE.
154	ln_dyninc = .FALSE.
155	ln_sshinc = .FALSE.
156	ln_seaiceinc = .FALSE.
157	ln_asmdin = .FALSE.
158	ln_asmiau = .TRUE.
159	ln_salfix = .FALSE.
160	ln_temnofreeze = .FALSE.
161	salfixmin = -9999
162	nitbkg = 0
163	nitdin = 0
164	nitiaustr = 1
165	nitiaufin = 150 ! = 10 days with ORCA2
166	niaufn = 0
167
168	REWIND ( numnam )
169	READ ( numnam, nam_asminc )
170
171	! Control print
172	IF(lwp) THEN
173	WRITE(numout,*)
174	WRITE(numout,*) 'asm_inc_init : Assimilation increment initialization :'
175	WRITE(numout,*) '~~~~~~~~~~~~'
176	WRITE(numout,*) ' Namelist namasm : set assimilation increment parameters'
177	WRITE(numout,*) ' Logical switch for writing out background state ln_bkgwri = ', ln_bkgwri
178	WRITE(numout,*) ' Logical switch for applying tracer increments ln_trainc = ', ln_trainc
179	WRITE(numout,*) ' Logical switch for applying velocity increments ln_dyninc = ', ln_dyninc
180	WRITE(numout,*) ' Logical switch for applying SSH increments ln_sshinc = ', ln_sshinc
181	WRITE(numout,*) ' Logical switch for Direct Initialization (DI) ln_asmdin = ', ln_asmdin
182	WRITE(numout,*) ' Logical switch for applying sea ice increments ln_seaiceinc = ', ln_seaiceinc
183	WRITE(numout,*) ' Logical switch for Incremental Analysis Updating (IAU) ln_asmiau = ', ln_asmiau
184	WRITE(numout,*) ' Timestep of background in [0,nitend-nit000-1] nitbkg = ', nitbkg
185	WRITE(numout,*) ' Timestep of background for DI in [0,nitend-nit000-1] nitdin = ', nitdin
186	WRITE(numout,*) ' Timestep of start of IAU interval in [0,nitend-nit000-1] nitiaustr = ', nitiaustr
187	WRITE(numout,*) ' Timestep of end of IAU interval in [0,nitend-nit000-1] nitiaufin = ', nitiaufin
188	WRITE(numout,*) ' Type of IAU weighting function niaufn = ', niaufn
189	WRITE(numout,*) ' Logical switch for ensuring that the sa > salfixmin ln_salfix = ', ln_salfix
190	WRITE(numout,*) ' Minimum salinity after applying the increments salfixmin = ', salfixmin
191	ENDIF
192
193	nitbkg_r = nitbkg + nit000 - 1 ! Background time referenced to nit000
194	nitdin_r = nitdin + nit000 - 1 ! Background time for DI referenced to nit000
195	nitiaustr_r = nitiaustr + nit000 - 1 ! Start of IAU interval referenced to nit000
196	nitiaufin_r = nitiaufin + nit000 - 1 ! End of IAU interval referenced to nit000
197
198	iiauper = nitiaufin_r - nitiaustr_r + 1 ! IAU interval length
199	icycper = nitend - nit000 + 1 ! Cycle interval length
200
201	! Date of final time step
202	CALL calc_date( nit000, nitend, ndate0, iitend_date )
203
204	! Background time for Jb referenced to ndate0
205	CALL calc_date( nit000, nitbkg_r, ndate0, iitbkg_date )
206
207	! Background time for DI referenced to ndate0
208	CALL calc_date( nit000, nitdin_r, ndate0, iitdin_date )
209
210	! IAU start time referenced to ndate0
211	CALL calc_date( nit000, nitiaustr_r, ndate0, iitiaustr_date )
212
213	! IAU end time referenced to ndate0
214	CALL calc_date( nit000, nitiaufin_r, ndate0, iitiaufin_date )
215
216	IF(lwp) THEN
217	WRITE(numout,*)
218	WRITE(numout,*) ' Time steps referenced to current cycle:'
219	WRITE(numout,*) ' iitrst = ', nit000 - 1
220	WRITE(numout,*) ' nit000 = ', nit000
221	WRITE(numout,*) ' nitend = ', nitend
222	WRITE(numout,*) ' nitbkg_r = ', nitbkg_r
223	WRITE(numout,*) ' nitdin_r = ', nitdin_r
224	WRITE(numout,*) ' nitiaustr_r = ', nitiaustr_r
225	WRITE(numout,*) ' nitiaufin_r = ', nitiaufin_r
226	WRITE(numout,*)
227	WRITE(numout,*) ' Dates referenced to current cycle:'
228	WRITE(numout,*) ' ndastp = ', ndastp
229	WRITE(numout,*) ' ndate0 = ', ndate0
230	WRITE(numout,*) ' iitend_date = ', iitend_date
231	WRITE(numout,*) ' iitbkg_date = ', iitbkg_date
232	WRITE(numout,*) ' iitdin_date = ', iitdin_date
233	WRITE(numout,*) ' iitiaustr_date = ', iitiaustr_date
234	WRITE(numout,*) ' iitiaufin_date = ', iitiaufin_date
235	ENDIF
236
237	IF ( nacc /= 0 ) &
238	& CALL ctl_stop( ' nacc /= 0 and key_asminc :', &
239	& ' Assimilation increments have only been implemented', &
240	& ' for synchronous time stepping' )
241
242	IF ( ( ln_asmdin ).AND.( ln_asmiau ) ) &
243	& CALL ctl_stop( ' ln_asmdin and ln_asmiau :', &
244	& ' Choose Direct Initialization OR Incremental Analysis Updating')
245
246	IF ( ( ( .NOT. ln_asmdin ).AND.( .NOT. ln_asmiau ) ) &
247	.AND.( ( ln_trainc ).OR.( ln_dyninc ).OR.( ln_sshinc ) .OR. ( ln_seaiceinc) )) &
248	& CALL ctl_stop( ' One or more of ln_trainc, ln_dyninc, ln_sshinc and ln_seaiceinc is set to .true.', &
249	& ' but ln_asmdin and ln_asmiau are both set to .false. :', &
250	& ' Inconsistent options')
251
252	IF ( ( ln_bkgwri ).AND.( ( ln_asmdin ).OR.( ln_asmiau ) ) ) &
253	& CALL ctl_stop( ' ln_bkgwri and either ln_asmdin or ln_asmiau are set to .true.:', &
254	& ' The background state must be written before applying the increments')
255
256	IF ( ( niaufn /= 0 ).AND.( niaufn /= 1 ) ) &
257	& CALL ctl_stop( ' niaufn /= 0 or niaufn /=1 :', &
258	& ' Type IAU weighting function is invalid')
259
260	IF ( ( .NOT. ln_trainc ).AND.( .NOT. ln_dyninc ).AND.( .NOT. ln_sshinc ).AND.( .NOT. ln_seaiceinc ) &
261	& ) &
262	& CALL ctl_warn( ' ln_trainc, ln_dyninc, ln_sshinc and ln_seaiceinc are set to .false. :', &
263	& ' The assimilation increments are not applied')
264
265	IF ( ( ln_asmiau ).AND.( nitiaustr == nitiaufin ) ) &
266	& CALL ctl_stop( ' nitiaustr = nitiaufin :', &
267	& ' IAU interval is of zero length')
268
269	IF ( ( ln_asmiau ).AND.( ( nitiaustr_r < nit000 ).OR.( nitiaufin_r > nitend ) ) ) &
270	& CALL ctl_stop( ' nitiaustr or nitiaufin :', &
271	& ' IAU starting or final time step is outside the cycle interval', &
272	& ' Valid range nit000 to nitend')
273
274	IF ( ( nitbkg_r < nit000 - 1 ).OR.( nitbkg_r > nitend ) ) &
275	& CALL ctl_stop( ' nitbkg :', &
276	& ' Background time step is outside the cycle interval')
277
278	IF ( ( nitdin_r < nit000 - 1 ).OR.( nitdin_r > nitend ) ) &
279	& CALL ctl_stop( ' nitdin :', &
280	& ' Background time step for Direct Initialization is outside', &
281	& ' the cycle interval')
282
283	IF ( nstop > 0 ) RETURN ! if there are any errors then go no further
284
285	!--------------------------------------------------------------------
286	! Initialize the Incremental Analysis Updating weighting function
287	!--------------------------------------------------------------------
288
289	IF ( ln_asmiau ) THEN
290
291	ALLOCATE( wgtiau( icycper ) )
292
293	wgtiau(:) = 0.0
294
295	IF ( niaufn == 0 ) THEN
296
297	!---------------------------------------------------------
298	! Constant IAU forcing
299	!---------------------------------------------------------
300
301	DO jt = 1, iiauper
302	wgtiau(jt+nitiaustr-1) = 1.0 / REAL( iiauper )
303	END DO
304
305	ELSEIF ( niaufn == 1 ) THEN
306
307	!---------------------------------------------------------
308	! Linear hat-like, centred in middle of IAU interval
309	!---------------------------------------------------------
310
311	! Compute the normalization factor
312	znorm = 0.0
313	IF ( MOD( iiauper, 2 ) == 0 ) THEN ! Even number of time steps in IAU interval
314	imid = iiauper / 2
315	DO jt = 1, imid
316	znorm = znorm + REAL( jt )
317	END DO
318	znorm = 2.0 * znorm
319	ELSE ! Odd number of time steps in IAU interval
320	imid = ( iiauper + 1 ) / 2
321	DO jt = 1, imid - 1
322	znorm = znorm + REAL( jt )
323	END DO
324	znorm = 2.0 * znorm + REAL( imid )
325	ENDIF
326	znorm = 1.0 / znorm
327
328	DO jt = 1, imid - 1
329	wgtiau(jt+nitiaustr-1) = REAL( jt ) * znorm
330	END DO
331	DO jt = imid, iiauper
332	wgtiau(jt+nitiaustr-1) = REAL( iiauper - jt + 1 ) * znorm
333	END DO
334
335	ENDIF
336
337	! Test that the integral of the weights over the weighting interval equals 1
338	IF(lwp) THEN
339	WRITE(numout,*)
340	WRITE(numout,*) 'asm_inc_init : IAU weights'
341	WRITE(numout,*) '~~~~~~~~~~~~'
342	WRITE(numout,*) ' time step IAU weight'
343	WRITE(numout,*) ' ========= ====================='
344	ztotwgt = 0.0
345	DO jt = 1, icycper
346	ztotwgt = ztotwgt + wgtiau(jt)
347	WRITE(numout,*) ' ', jt, ' ', wgtiau(jt)
348	END DO
349	WRITE(numout,*) ' ==================================='
350	WRITE(numout,*) ' Time-integrated weight = ', ztotwgt
351	WRITE(numout,*) ' ==================================='
352	ENDIF
353
354	ENDIF
355
356	!--------------------------------------------------------------------
357	! Allocate and initialize the increment arrays
358	!--------------------------------------------------------------------
359
360	ALLOCATE( t_bkginc(jpi,jpj,jpk) )
361	ALLOCATE( s_bkginc(jpi,jpj,jpk) )
362	ALLOCATE( u_bkginc(jpi,jpj,jpk) )
363	ALLOCATE( v_bkginc(jpi,jpj,jpk) )
364	ALLOCATE( ssh_bkginc(jpi,jpj) )
365	ALLOCATE( seaice_bkginc(jpi,jpj))
366	#if defined key_asminc
367	ALLOCATE( ssh_iau(jpi,jpj) )
368	#endif
369	t_bkginc(:,:,:) = 0.0
370	s_bkginc(:,:,:) = 0.0
371	u_bkginc(:,:,:) = 0.0
372	v_bkginc(:,:,:) = 0.0
373	ssh_bkginc(:,:) = 0.0
374	seaice_bkginc(:,:) = 0.0
375	#if defined key_asminc
376	ssh_iau(:,:) = 0.0
377	#endif
378	IF ( ( ln_trainc ).OR.( ln_dyninc ).OR.( ln_sshinc ).OR.( ln_seaiceinc ) ) THEN
379
380	!--------------------------------------------------------------------
381	! Read the increments from file
382	!--------------------------------------------------------------------
383
384	CALL iom_open( c_asminc, inum )
385
386	CALL iom_get( inum, 'time', zdate_inc )
387
388	CALL iom_get( inum, 'z_inc_dateb', z_inc_dateb )
389	CALL iom_get( inum, 'z_inc_datef', z_inc_datef )
390	z_inc_dateb = zdate_inc
391	z_inc_datef = zdate_inc
392
393	IF(lwp) THEN
394	WRITE(numout,*)
395	WRITE(numout,*) 'asm_inc_init : Assimilation increments valid ', &
396	& ' between dates ', NINT( z_inc_dateb ),' and ', &
397	& NINT( z_inc_datef )
398	WRITE(numout,*) '~~~~~~~~~~~~'
399	ENDIF
400
401	IF ( ( NINT( z_inc_dateb ) < ndastp ) &
402	& .OR.( NINT( z_inc_datef ) > iitend_date ) ) &
403	& CALL ctl_warn( ' Validity time of assimilation increments is ', &
404	& ' outside the assimilation interval' )
405
406	IF ( ( ln_asmdin ).AND.( NINT( zdate_inc ) /= iitdin_date ) ) &
407	& CALL ctl_warn( ' Validity time of assimilation increments does ', &
408	& ' not agree with Direct Initialization time' )
409
410	IF ( ln_trainc ) THEN
411	CALL iom_get( inum, jpdom_autoglo, 'bckint', t_bkginc, 1 )
412	CALL iom_get( inum, jpdom_autoglo, 'bckins', s_bkginc, 1 )
413	! Apply the masks
414	t_bkginc(:,:,:) = t_bkginc(:,:,:) * tmask(:,:,:)
415	s_bkginc(:,:,:) = s_bkginc(:,:,:) * tmask(:,:,:)
416	! Set missing increments to 0.0 rather than 1e+20
417	! to allow for differences in masks
418	WHERE( ABS( t_bkginc(:,:,:) ) > 1.0e+10 ) t_bkginc(:,:,:) = 0.0
419	WHERE( ABS( s_bkginc(:,:,:) ) > 1.0e+10 ) s_bkginc(:,:,:) = 0.0
420	ENDIF
421
422	IF ( ln_dyninc ) THEN
423	CALL iom_get( inum, jpdom_autoglo, 'bckinu', u_bkginc, 1 )
424	CALL iom_get( inum, jpdom_autoglo, 'bckinv', v_bkginc, 1 )
425	! Apply the masks
426	u_bkginc(:,:,:) = u_bkginc(:,:,:) * umask(:,:,:)
427	v_bkginc(:,:,:) = v_bkginc(:,:,:) * vmask(:,:,:)
428	! Set missing increments to 0.0 rather than 1e+20
429	! to allow for differences in masks
430	WHERE( ABS( u_bkginc(:,:,:) ) > 1.0e+10 ) u_bkginc(:,:,:) = 0.0
431	WHERE( ABS( v_bkginc(:,:,:) ) > 1.0e+10 ) v_bkginc(:,:,:) = 0.0
432	ENDIF
433
434	IF ( ln_sshinc ) THEN
435	CALL iom_get( inum, jpdom_autoglo, 'bckineta', ssh_bkginc, 1 )
436	! Apply the masks
437	ssh_bkginc(:,:) = ssh_bkginc(:,:) * tmask(:,:,1)
438	! Set missing increments to 0.0 rather than 1e+20
439	! to allow for differences in masks
440	WHERE( ABS( ssh_bkginc(:,:) ) > 1.0e+10 ) ssh_bkginc(:,:) = 0.0
441	ENDIF
442
443	IF ( ln_seaiceinc ) THEN
444	CALL iom_get( inum, jpdom_autoglo, 'bckinseaice', seaice_bkginc, 1 )
445	! Apply the masks
446	seaice_bkginc(:,:) = seaice_bkginc(:,:) * tmask(:,:,1)
447	! Set missing increments to 0.0 rather than 1e+20
448	! to allow for differences in masks
449	WHERE( ABS( seaice_bkginc(:,:) ) > 1.0e+10 ) seaice_bkginc(:,:) = 0.0
450	ENDIF
451
452	CALL iom_close( inum )
453
454	ENDIF
455
456	!-----------------------------------------------------------------------
457	! Apply divergence damping filter
458	!-----------------------------------------------------------------------
459
460	IF ( ln_dyninc .AND. nn_divdmp > 0 ) THEN
461
462	CALL wrk_alloc(jpi,jpj,hdiv)
463
464	DO jt = 1, nn_divdmp
465
466	DO jk = 1, jpkm1
467
468	hdiv(:,:) = 0._wp
469
470	DO jj = 2, jpjm1
471	DO ji = fs_2, fs_jpim1 ! vector opt.
472	hdiv(ji,jj) = &
473	( e2u(ji ,jj ) * fse3u(ji ,jj ,jk) * u_bkginc(ji ,jj ,jk) &
474	- e2u(ji-1,jj ) * fse3u(ji-1,jj ,jk) * u_bkginc(ji-1,jj ,jk) &
475	+ e1v(ji ,jj ) * fse3v(ji ,jj ,jk) * v_bkginc(ji ,jj ,jk) &
476	- e1v(ji ,jj-1) * fse3v(ji ,jj-1,jk) * v_bkginc(ji ,jj-1,jk) ) &
477	/ ( e1t(ji,jj) * e2t(ji,jj) * fse3t(ji,jj,jk) )
478	END DO
479	END DO
480
481	CALL lbc_lnk( hdiv, 'T', 1. ) ! lateral boundary cond. (no sign change)
482
483	DO jj = 2, jpjm1
484	DO ji = fs_2, fs_jpim1 ! vector opt.
485	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) &
486	- e1t(ji ,jj)e2t(ji ,jj) hdiv(ji ,jj) ) &
487	/ e1u(ji,jj) * umask(ji,jj,jk)
488	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) &
489	- e1t(ji,jj )e2t(ji,jj ) hdiv(ji,jj ) ) &
490	/ e2v(ji,jj) * vmask(ji,jj,jk)
491	END DO
492	END DO
493
494	END DO
495
496	END DO
497
498	CALL wrk_dealloc(jpi,jpj,hdiv)
499
500	ENDIF
501
502
503
504	!-----------------------------------------------------------------------
505	! Allocate and initialize the background state arrays
506	!-----------------------------------------------------------------------
507
508	IF ( ln_asmdin ) THEN
509
510	ALLOCATE( t_bkg(jpi,jpj,jpk) )
511	ALLOCATE( s_bkg(jpi,jpj,jpk) )
512	ALLOCATE( u_bkg(jpi,jpj,jpk) )
513	ALLOCATE( v_bkg(jpi,jpj,jpk) )
514	ALLOCATE( ssh_bkg(jpi,jpj) )
515
516	t_bkg(:,:,:) = 0.0
517	s_bkg(:,:,:) = 0.0
518	u_bkg(:,:,:) = 0.0
519	v_bkg(:,:,:) = 0.0
520	ssh_bkg(:,:) = 0.0
521
522	!--------------------------------------------------------------------
523	! Read from file the background state at analysis time
524	!--------------------------------------------------------------------
525
526	CALL iom_open( c_asmdin, inum )
527
528	CALL iom_get( inum, 'rdastp', zdate_bkg )
529
530	IF(lwp) THEN
531	WRITE(numout,*)
532	WRITE(numout,*) 'asm_inc_init : Assimilation background state valid at : ', &
533	& NINT( zdate_bkg )
534	WRITE(numout,*) '~~~~~~~~~~~~'
535	ENDIF
536
537	IF ( NINT( zdate_bkg ) /= iitdin_date ) &
538	& CALL ctl_warn( ' Validity time of assimilation background state does', &
539	& ' not agree with Direct Initialization time' )
540
541	IF ( ln_trainc ) THEN
542	CALL iom_get( inum, jpdom_autoglo, 'tn', t_bkg )
543	CALL iom_get( inum, jpdom_autoglo, 'sn', s_bkg )
544	t_bkg(:,:,:) = t_bkg(:,:,:) * tmask(:,:,:)
545	s_bkg(:,:,:) = s_bkg(:,:,:) * tmask(:,:,:)
546	ENDIF
547
548	IF ( ln_dyninc ) THEN
549	CALL iom_get( inum, jpdom_autoglo, 'un', u_bkg )
550	CALL iom_get( inum, jpdom_autoglo, 'vn', v_bkg )
551	u_bkg(:,:,:) = u_bkg(:,:,:) * umask(:,:,:)
552	v_bkg(:,:,:) = v_bkg(:,:,:) * vmask(:,:,:)
553	ENDIF
554
555	IF ( ln_sshinc ) THEN
556	CALL iom_get( inum, jpdom_autoglo, 'sshn', ssh_bkg )
557	ssh_bkg(:,:) = ssh_bkg(:,:) * tmask(:,:,1)
558	ENDIF
559
560	CALL iom_close( inum )
561
562	ENDIF
563	!
564	END SUBROUTINE asm_inc_init
565
566
567	SUBROUTINE calc_date( kit000, kt, kdate0, kdate )
568	!!----------------------------------------------------------------------
569	!! * ROUTINE calc_date *
570	!!
571	!! ** Purpose : Compute the calendar date YYYYMMDD at a given time step.
572	!!
573	!! ** Method : Compute the calendar date YYYYMMDD at a given time step.
574	!!
575	!! ** Action :
576	!!----------------------------------------------------------------------
577	INTEGER, INTENT(IN) :: kit000 ! Initial time step
578	INTEGER, INTENT(IN) :: kt ! Current time step referenced to kit000
579	INTEGER, INTENT(IN) :: kdate0 ! Initial date
580	INTEGER, INTENT(OUT) :: kdate ! Current date reference to kdate0
581	!
582	INTEGER :: iyea0 ! Initial year
583	INTEGER :: imon0 ! Initial month
584	INTEGER :: iday0 ! Initial day
585	INTEGER :: iyea ! Current year
586	INTEGER :: imon ! Current month
587	INTEGER :: iday ! Current day
588	INTEGER :: idaystp ! Number of days between initial and current date
589	INTEGER :: idaycnt ! Day counter
590
591	INTEGER, DIMENSION(12) :: imonth_len !: length in days of the months of the current year
592
593	!-----------------------------------------------------------------------
594	! Compute the calendar date YYYYMMDD
595	!-----------------------------------------------------------------------
596
597	! Initial date
598	iyea0 = kdate0 / 10000
599	imon0 = ( kdate0 - ( iyea0 * 10000 ) ) / 100
600	iday0 = kdate0 - ( iyea0 * 10000 ) - ( imon0 * 100 )
601
602	! Check that kt >= kit000 - 1
603	IF ( kt < kit000 - 1 ) CALL ctl_stop( ' kt must be >= kit000 - 1')
604
605	! If kt = kit000 - 1 then set the date to the restart date
606	IF ( kt == kit000 - 1 ) THEN
607
608	kdate = ndastp
609	RETURN
610
611	ENDIF
612
613	! Compute the number of days from the initial date
614	idaystp = INT( REAL( kt - kit000 ) * rdt / 86400. )
615
616	iday = iday0
617	imon = imon0
618	iyea = iyea0
619	idaycnt = 0
620
621	CALL calc_month_len( iyea, imonth_len )
622
623	DO WHILE ( idaycnt < idaystp )
624	iday = iday + 1
625	IF ( iday > imonth_len(imon) ) THEN
626	iday = 1
627	imon = imon + 1
628	ENDIF
629	IF ( imon > 12 ) THEN
630	imon = 1
631	iyea = iyea + 1
632	CALL calc_month_len( iyea, imonth_len ) ! update month lengths
633	ENDIF
634	idaycnt = idaycnt + 1
635	END DO
636	!
637	kdate = iyea * 10000 + imon * 100 + iday
638	!
639	END SUBROUTINE
640
641
642	SUBROUTINE calc_month_len( iyear, imonth_len )
643	!!----------------------------------------------------------------------
644	!! * ROUTINE calc_month_len *
645	!!
646	!! ** Purpose : Compute the number of days in a months given a year.
647	!!
648	!! ** Method :
649	!!----------------------------------------------------------------------
650	INTEGER, DIMENSION(12) :: imonth_len !: length in days of the months of the current year
651	INTEGER :: iyear !: year
652	!!----------------------------------------------------------------------
653	!
654	! length of the month of the current year (from nleapy, read in namelist)
655	IF ( nleapy < 2 ) THEN
656	imonth_len(:) = (/ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 /)
657	IF ( nleapy == 1 ) THEN ! we are using calendar with leap years
658	IF ( MOD(iyear, 4) == 0 .AND. ( MOD(iyear, 400) == 0 .OR. MOD(iyear, 100) /= 0 ) ) THEN
659	imonth_len(2) = 29
660	ENDIF
661	ENDIF
662	ELSE
663	imonth_len(:) = nleapy ! all months with nleapy days per year
664	ENDIF
665	!
666	END SUBROUTINE
667
668
669	SUBROUTINE tra_asm_inc( kt )
670	!!----------------------------------------------------------------------
671	!! * ROUTINE tra_asm_inc *
672	!!
673	!! ** Purpose : Apply the tracer (T and S) assimilation increments
674	!!
675	!! ** Method : Direct initialization or Incremental Analysis Updating
676	!!
677	!! ** Action :
678	!!----------------------------------------------------------------------
679	INTEGER, INTENT(IN) :: kt ! Current time step
680	!
681	INTEGER :: ji,jj,jk
682	INTEGER :: it
683	REAL(wp) :: zincwgt ! IAU weight for current time step
684	REAL (wp), DIMENSION(jpi,jpj,jpk) :: fzptnz ! 3d freezing point values
685	!!----------------------------------------------------------------------
686
687	! freezing point calculation taken from oc_fz_pt (but calculated for all depths)
688	! used to prevent the applied increments taking the temperature below the local freezing point
689
690	#if defined key_cice
691	fzptnz(:,:,:) = -1.8_wp
692	#else
693	DO jk = 1, jpk
694	DO jj = 1, jpj
695	DO ji = 1, jpk
696	fzptnz (ji,jj,jk) = ( -0.0575_wp + 1.710523e-3_wp * SQRT( tsn(ji,jj,jk,jp_sal) ) &
697	- 2.154996e-4_wp * tsn(ji,jj,jk,jp_sal) ) * tsn(ji,jj,jk,jp_sal) &
698	- 7.53e-4_wp * fsdepw(ji,jj,jk) ! (pressure in dbar)
699	END DO
700	END DO
701	END DO
702	#endif
703
704	IF ( ln_asmiau ) THEN
705
706	!--------------------------------------------------------------------
707	! Incremental Analysis Updating
708	!--------------------------------------------------------------------
709
710	IF ( ( kt >= nitiaustr_r ).AND.( kt <= nitiaufin_r ) ) THEN
711
712	it = kt - nit000 + 1
713	zincwgt = wgtiau(it) / rdt ! IAU weight for the current time step
714
715	IF(lwp) THEN
716	WRITE(numout,*)
717	WRITE(numout,*) 'tra_asm_inc : Tracer IAU at time step = ', &
718	& kt,' with IAU weight = ', wgtiau(it)
719	WRITE(numout,*) '~~~~~~~~~~~~'
720	ENDIF
721
722	! Update the tracer tendencies
723	DO jk = 1, jpkm1
724	IF (ln_temnofreeze) THEN
725	! Do not apply negative increments if the temperature will fall below freezing
726	WHERE(t_bkginc(:,:,jk) > 0.0_wp .OR. &
727	& tsn(:,:,jk,jp_tem) + tsa(:,:,jk,jp_tem) + t_bkginc(:,:,jk) * wgtiau(it) > fzptnz(:,:,jk) )
728	tsa(:,:,jk,jp_tem) = tsa(:,:,jk,jp_tem) + t_bkginc(:,:,jk) * zincwgt
729	END WHERE
730	ELSE
731	tsa(:,:,jk,jp_tem) = tsa(:,:,jk,jp_tem) + t_bkginc(:,:,jk) * zincwgt
732	ENDIF
733	IF (ln_salfix) THEN
734	! Do not apply negative increments if the salinity will fall below a specified
735	! minimum value salfixmin
736	WHERE(s_bkginc(:,:,jk) > 0.0_wp .OR. &
737	& tsn(:,:,jk,jp_sal) + tsa(:,:,jk,jp_sal) + s_bkginc(:,:,jk) * wgtiau(it) > salfixmin )
738	tsa(:,:,jk,jp_sal) = tsa(:,:,jk,jp_sal) + s_bkginc(:,:,jk) * zincwgt
739	END WHERE
740	ELSE
741	tsa(:,:,jk,jp_sal) = tsa(:,:,jk,jp_sal) + s_bkginc(:,:,jk) * zincwgt
742	ENDIF
743	END DO
744
745	ENDIF
746
747	IF ( kt == nitiaufin_r + 1 ) THEN ! For bias crcn to work
748	DEALLOCATE( t_bkginc )
749	DEALLOCATE( s_bkginc )
750	ENDIF
751
752
753	ELSEIF ( ln_asmdin ) THEN
754
755	!--------------------------------------------------------------------
756	! Direct Initialization
757	!--------------------------------------------------------------------
758
759	IF ( kt == nitdin_r ) THEN
760
761	neuler = 0 ! Force Euler forward step
762
763	! Initialize the now fields with the background + increment
764	IF (ln_temnofreeze) THEN
765	! Do not apply negative increments if the temperature will fall below freezing
766	WHERE(t_bkginc(:,:,:) > 0.0_wp .OR. &
767	& tsn(:,:,:,jp_tem) + t_bkginc(:,:,:) > fzptnz(:,:,:) )
768	tsn(:,:,:,jp_tem) = t_bkg(:,:,:) + t_bkginc(:,:,:)
769	END WHERE
770	ELSE
771	tsn(:,:,:,jp_tem) = t_bkg(:,:,:) + t_bkginc(:,:,:)
772	ENDIF
773	IF (ln_salfix) THEN
774	! Do not apply negative increments if the salinity will fall below a specified
775	! minimum value salfixmin
776	WHERE(s_bkginc(:,:,:) > 0.0_wp .OR. &
777	& tsn(:,:,:,jp_sal) + s_bkginc(:,:,:) > salfixmin )
778	tsn(:,:,:,jp_sal) = s_bkg(:,:,:) + s_bkginc(:,:,:)
779	END WHERE
780	ELSE
781	tsn(:,:,:,jp_sal) = s_bkg(:,:,:) + s_bkginc(:,:,:)
782	ENDIF
783
784	tsb(:,:,:,:) = tsn(:,:,:,:) ! Update before fields
785
786	CALL eos( tsb, rhd, rhop ) ! Before potential and in situ densities
787
788	IF( ln_zps .AND. .NOT. lk_c1d ) &
789	& CALL zps_hde( nit000, jpts, tsb, & ! Partial steps: before horizontal derivative
790	& gtsu, gtsv, rhd, & ! of T, S, rd at the bottom ocean level
791	& gru , grv )
792
793	#if defined key_zdfkpp
794	CALL eos( tsn, rhd ) ! Compute rhd
795	#endif
796
797	DEALLOCATE( t_bkginc )
798	DEALLOCATE( s_bkginc )
799	DEALLOCATE( t_bkg )
800	DEALLOCATE( s_bkg )
801	ENDIF
802	!
803	ENDIF
804	! Perhaps the following call should be in step
805	IF ( ln_seaiceinc ) CALL seaice_asm_inc ( kt ) ! apply sea ice concentration increment
806	!
807	END SUBROUTINE tra_asm_inc
808
809
810	SUBROUTINE dyn_asm_inc( kt )
811	!!----------------------------------------------------------------------
812	!! * ROUTINE dyn_asm_inc *
813	!!
814	!! ** Purpose : Apply the dynamics (u and v) assimilation increments.
815	!!
816	!! ** Method : Direct initialization or Incremental Analysis Updating.
817	!!
818	!! ** Action :
819	!!----------------------------------------------------------------------
820	INTEGER, INTENT(IN) :: kt ! Current time step
821	!
822	INTEGER :: jk
823	INTEGER :: it
824	REAL(wp) :: zincwgt ! IAU weight for current time step
825	!!----------------------------------------------------------------------
826
827	IF ( ln_asmiau ) THEN
828
829	!--------------------------------------------------------------------
830	! Incremental Analysis Updating
831	!--------------------------------------------------------------------
832
833	IF ( ( kt >= nitiaustr_r ).AND.( kt <= nitiaufin_r ) ) THEN
834
835	it = kt - nit000 + 1
836	zincwgt = wgtiau(it) / rdt ! IAU weight for the current time step
837
838	IF(lwp) THEN
839	WRITE(numout,*)
840	WRITE(numout,*) 'dyn_asm_inc : Dynamics IAU at time step = ', &
841	& kt,' with IAU weight = ', wgtiau(it)
842	WRITE(numout,*) '~~~~~~~~~~~~'
843	ENDIF
844
845	! Update the dynamic tendencies
846	DO jk = 1, jpkm1
847	ua(:,:,jk) = ua(:,:,jk) + u_bkginc(:,:,jk) * zincwgt
848	va(:,:,jk) = va(:,:,jk) + v_bkginc(:,:,jk) * zincwgt
849	END DO
850
851	IF ( kt == nitiaufin_r ) THEN
852	DEALLOCATE( u_bkginc )
853	DEALLOCATE( v_bkginc )
854	ENDIF
855
856	ENDIF
857
858	ELSEIF ( ln_asmdin ) THEN
859
860	!--------------------------------------------------------------------
861	! Direct Initialization
862	!--------------------------------------------------------------------
863
864	IF ( kt == nitdin_r ) THEN
865
866	neuler = 0 ! Force Euler forward step
867
868	! Initialize the now fields with the background + increment
869	un(:,:,:) = u_bkg(:,:,:) + u_bkginc(:,:,:)
870	vn(:,:,:) = v_bkg(:,:,:) + v_bkginc(:,:,:)
871
872	ub(:,:,:) = un(:,:,:) ! Update before fields
873	vb(:,:,:) = vn(:,:,:)
874
875	DEALLOCATE( u_bkg )
876	DEALLOCATE( v_bkg )
877	DEALLOCATE( u_bkginc )
878	DEALLOCATE( v_bkginc )
879	ENDIF
880	!
881	ENDIF
882	!
883	END SUBROUTINE dyn_asm_inc
884
885
886	SUBROUTINE ssh_asm_inc( kt )
887	!!----------------------------------------------------------------------
888	!! * ROUTINE ssh_asm_inc *
889	!!
890	!! ** Purpose : Apply the sea surface height assimilation increment.
891	!!
892	!! ** Method : Direct initialization or Incremental Analysis Updating.
893	!!
894	!! ** Action :
895	!!----------------------------------------------------------------------
896	INTEGER, INTENT(IN) :: kt ! Current time step
897	!
898	INTEGER :: it
899	INTEGER :: jk
900	REAL(wp) :: zincwgt ! IAU weight for current time step
901	!!----------------------------------------------------------------------
902
903	IF ( ln_asmiau ) THEN
904
905	!--------------------------------------------------------------------
906	! Incremental Analysis Updating
907	!--------------------------------------------------------------------
908
909	IF ( ( kt >= nitiaustr_r ).AND.( kt <= nitiaufin_r ) ) THEN
910
911	it = kt - nit000 + 1
912	zincwgt = wgtiau(it) / rdt ! IAU weight for the current time step
913
914	IF(lwp) THEN
915	WRITE(numout,*)
916	WRITE(numout,*) 'ssh_asm_inc : SSH IAU at time step = ', &
917	& kt,' with IAU weight = ', wgtiau(it)
918	WRITE(numout,*) '~~~~~~~~~~~~'
919	ENDIF
920
921	! Save the tendency associated with the IAU weighted SSH increment
922	! (applied in dynspg.*)
923	#if defined key_asminc
924	ssh_iau(:,:) = ssh_bkginc(:,:) * zincwgt
925	#endif
926	IF ( kt == nitiaufin_r ) THEN
927	DEALLOCATE( ssh_bkginc )
928	ENDIF
929
930	ENDIF
931
932	ELSEIF ( ln_asmdin ) THEN
933
934	!--------------------------------------------------------------------
935	! Direct Initialization
936	!--------------------------------------------------------------------
937
938	IF ( kt == nitdin_r ) THEN
939
940	neuler = 0 ! Force Euler forward step
941
942	! Initialize the now fields the background + increment
943	sshn(:,:) = ssh_bkg(:,:) + ssh_bkginc(:,:)
944
945	! Update before fields
946	sshb(:,:) = sshn(:,:)
947
948	IF( lk_vvl ) THEN
949	DO jk = 1, jpk
950	fse3t_b(:,:,jk) = fse3t_n(:,:,jk)
951	END DO
952	ENDIF
953
954	DEALLOCATE( ssh_bkg )
955	DEALLOCATE( ssh_bkginc )
956
957	ENDIF
958	!
959	ENDIF
960	!
961	END SUBROUTINE ssh_asm_inc
962
963	SUBROUTINE seaice_asm_inc( kt, kindic )
964	!!----------------------------------------------------------------------
965	!! * ROUTINE seaice_asm_inc *
966	!!
967	!! ** Purpose : Apply the sea ice assimilation increment.
968	!!
969	!! ** Method : Direct initialization or Incremental Analysis Updating.
970	!!
971	!! ** Action :
972	!!
973	!! History :
974	!! ! 07-2011 (D. Lea) Initial version based on ssh_asm_inc
975	!!----------------------------------------------------------------------
976
977	IMPLICIT NONE
978
979	!! * Arguments
980	INTEGER, INTENT(IN) :: kt ! Current time step
981	INTEGER, OPTIONAL, INTENT(IN) :: kindic ! flag for disabling the deallocation
982
983	!! * Local declarations
984	INTEGER :: it
985	REAL(wp) :: zincwgt ! IAU weight for current time step
986
987	#if defined key_lim3 \|\| defined key_lim2
988	REAL(wp), DIMENSION(jpi,jpj) :: zofrld, zohicif, zseaicendg, zhicifinc ! LIM
989	REAL(wp) :: zhicifmin=0.5_wp ! ice minimum depth in metres
990
991	#endif
992
993
994	IF ( ln_asmiau ) THEN
995
996	!--------------------------------------------------------------------
997	! Incremental Analysis Updating
998	!--------------------------------------------------------------------
999
1000	IF ( ( kt >= nitiaustr_r ).AND.( kt <= nitiaufin_r ) ) THEN
1001
1002	it = kt - nit000 + 1
1003	zincwgt = wgtiau(it) ! IAU weight for the current time step
1004	! note this is not a tendency so should not be divided by rdt (as with the tracer and other increments)
1005
1006	IF(lwp) THEN
1007	WRITE(numout,*)
1008	WRITE(numout,*) 'seaice_asm_inc : sea ice conc IAU at time step = ', &
1009	& kt,' with IAU weight = ', wgtiau(it)
1010	WRITE(numout,*) '~~~~~~~~~~~~'
1011	ENDIF
1012
1013	#if defined key_lim3 \|\| defined key_lim2
1014
1015	zofrld(:,:)=frld(:,:)
1016	zohicif(:,:)=hicif(:,:)
1017
1018	frld = MIN( MAX( frld(:,:) - seaice_bkginc(:,:) * zincwgt, 0.0_wp), 1.0_wp)
1019	pfrld = MIN( MAX( pfrld(:,:) - seaice_bkginc(:,:) * zincwgt, 0.0_wp), 1.0_wp)
1020	fr_i(:,:) = 1.0_wp - frld(:,:) ! adjust ice fraction
1021
1022	zseaicendg(:,:)=zofrld(:,:) - frld(:,:) ! find out actual sea ice nudge applied
1023
1024	! Nudge sea ice depth to bring it up to a required minimum depth
1025
1026	WHERE( zseaicendg(:,:) > 0.0_wp .AND. hicif(:,:) < zhicifmin )
1027	zhicifinc(:,:) = (zhicifmin - hicif(:,:)) * zincwgt
1028	ELSEWHERE
1029	zhicifinc(:,:) = 0.0_wp
1030	END WHERE
1031
1032	! nudge ice depth
1033	hicif(:,:)=hicif(:,:) + zhicifinc(:,:)
1034	phicif(:,:)=phicif(:,:) + zhicifinc(:,:)
1035
1036	! seaice salinity balancing (to add)
1037
1038	#endif
1039
1040	#if defined key_cice
1041
1042	! Pass ice increment tendency into CICE
1043	ndaice_da(:,:) = seaice_bkginc(:,:) * zincwgt / rdt
1044
1045	#endif
1046
1047	IF ( kt == nitiaufin_r ) THEN
1048	DEALLOCATE( seaice_bkginc )
1049	ENDIF
1050
1051	ELSE
1052
1053	#if defined key_cice
1054
1055	! Zero ice increment tendency into CICE
1056	ndaice_da(:,:) = 0.0_wp
1057
1058	#endif
1059
1060	ENDIF
1061
1062	ELSEIF ( ln_asmdin ) THEN
1063
1064	!--------------------------------------------------------------------
1065	! Direct Initialization
1066	!--------------------------------------------------------------------
1067
1068	IF ( kt == nitdin_r ) THEN
1069
1070	neuler = 0 ! Force Euler forward step
1071
1072	#if defined key_lim3 \|\| defined key_lim2
1073
1074	zofrld(:,:)=frld(:,:)
1075	zohicif(:,:)=hicif(:,:)
1076
1077	! Initialize the now fields the background + increment
1078
1079	frld(:,:) = MIN( MAX( frld(:,:) - seaice_bkginc(:,:), 0.0_wp), 1.0_wp)
1080	pfrld(:,:) = frld(:,:)
1081	fr_i(:,:) = 1.0_wp - frld(:,:) ! adjust ice fraction
1082
1083	zseaicendg(:,:)=zofrld(:,:) - frld(:,:) ! find out actual sea ice nudge applied
1084
1085	! Nudge sea ice depth to bring it up to a required minimum depth
1086
1087	WHERE( zseaicendg(:,:) > 0.0_wp .AND. hicif(:,:) < zhicifmin )
1088	zhicifinc(:,:) = (zhicifmin - hicif(:,:)) * zincwgt
1089	ELSEWHERE
1090	zhicifinc(:,:) = 0.0_wp
1091	END WHERE
1092
1093	! nudge ice depth
1094	hicif(:,:)=hicif(:,:) + zhicifinc(:,:)
1095	phicif(:,:)=phicif(:,:)
1096
1097	! seaice salinity balancing (to add)
1098
1099	#endif
1100
1101	#if defined key_cice
1102
1103	! Pass ice increment tendency into CICE - is this correct?
1104	ndaice_da(:,:) = seaice_bkginc(:,:) / rdt
1105
1106	#endif
1107	IF ( .NOT. PRESENT(kindic) ) THEN
1108	DEALLOCATE( seaice_bkginc )
1109	END IF
1110
1111	ELSE
1112
1113	#if defined key_cice
1114
1115	! Zero ice increment tendency into CICE
1116	ndaice_da(:,:) = 0.0_wp
1117
1118	#endif
1119
1120	ENDIF
1121
1122	!#if defined key_lim3 \|\| defined key_lim2 \|\| defined key_cice
1123	!
1124	! IF (ln_seaicebal ) THEN
1125	! !! balancing salinity increments
1126	! !! simple case from limflx.F90 (doesn't include a mass flux)
1127	! !! assumption is that as ice concentration is reduced or increased
1128	! !! the snow and ice depths remain constant
1129	! !! note that snow is being created where ice concentration is being increased
1130	! !! - could be more sophisticated and
1131	! !! not do this (but would need to alter h_snow)
1132	!
1133	! usave(:,:,:)=sb(:,:,:) ! use array as a temporary store
1134	!
1135	! DO jj = 1, jpj
1136	! DO ji = 1, jpi
1137	! ! calculate change in ice and snow mass per unit area
1138	! ! positive values imply adding salt to the ocean (results from ice formation)
1139	! ! fwf : ice formation and melting
1140	!
1141	! zfons = ( -nfresh_da(ji,jj)soce + nfsalt_da(ji,jj) )rdt
1142	!
1143	! ! change salinity down to mixed layer depth
1144	! mld=hmld_kara(ji,jj)
1145	!
1146	! ! prevent small mld
1147	! ! less than 10m can cause salinity instability
1148	! IF (mld < 10) mld=10
1149	!
1150	! ! set to bottom of a level
1151	! DO jk = jpk-1, 2, -1
1152	! IF ((mld > gdepw(ji,jj,jk)) .and. (mld < gdepw(ji,jj,jk+1))) THEN
1153	! mld=gdepw(ji,jj,jk+1)
1154	! jkmax=jk
1155	! ENDIF
1156	! ENDDO
1157	!
1158	! ! avoid applying salinity balancing in shallow water or on land
1159	! !
1160	!
1161	! ! dsal_ocn (psu kg m^-2) / (kg m^-3 * m)
1162	!
1163	! dsal_ocn=0.0_wp
1164	! sal_thresh=5.0_wp ! minimum salinity threshold for salinity balancing
1165	!
1166	! if (tmask(ji,jj,1) > 0 .AND. tmask(ji,jj,jkmax) > 0 ) &
1167	! dsal_ocn = zfons / (rhop(ji,jj,1) * mld)
1168	!
1169	! ! put increments in for levels in the mixed layer
1170	! ! but prevent salinity below a threshold value
1171	!
1172	! DO jk = 1, jkmax
1173	!
1174	! IF (dsal_ocn > 0.0_wp .or. sb(ji,jj,jk)+dsal_ocn > sal_thresh) THEN
1175	! sb(ji,jj,jk) = sb(ji,jj,jk) + dsal_ocn
1176	! sn(ji,jj,jk) = sn(ji,jj,jk) + dsal_ocn
1177	! ENDIF
1178	!
1179	! ENDDO
1180	!
1181	! ! ! salt exchanges at the ice/ocean interface
1182	! ! zpmess = zfons / rdt_ice ! rdt_ice is ice timestep
1183	! !
1184	! !! Adjust fsalt. A +ve fsalt means adding salt to ocean
1185	! !! fsalt(ji,jj) = fsalt(ji,jj) + zpmess ! adjust fsalt
1186	! !!
1187	! !! emps(ji,jj) = emps(ji,jj) + zpmess ! or adjust emps (see icestp1d)
1188	! !! ! E-P (kg m-2 s-2)
1189	! ! emp(ji,jj) = emp(ji,jj) + zpmess ! E-P (kg m-2 s-2)
1190	! ENDDO !ji
1191	! ENDDO !jj!
1192	!
1193	! ENDIF !ln_seaicebal
1194	!
1195	!#endif
1196
1197
1198	ENDIF
1199
1200	END SUBROUTINE seaice_asm_inc
1201	!!======================================================================
1202	END MODULE asminc

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