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

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

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

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

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