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asminc.F90 in branches/2012/dev_v3_4_STABLE_2012/NEMOGCM/NEMO/OPA_SRC/ASM – NEMO

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source: branches/2012/dev_v3_4_STABLE_2012/NEMOGCM/NEMO/OPA_SRC/ASM/asminc.F90 @ 5168

Last change on this file since 5168 was 5168, checked in by pabouttier, 9 years ago
Fixed several bugs described in Ticket #1360
Property svn:keywords set to `Id`
File size: 48.0 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 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_lim2
38	USE ice_2 ! LIM2
39	#endif
40	USE sbc_oce ! Surface boundary condition variables.
41	USE domvvl
42
43	IMPLICIT NONE
44	PRIVATE
45
46	PUBLIC asm_inc_rea_nam !: Read namelist for ASM
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 increment
53
54	#if defined key_asminc
55	LOGICAL, PUBLIC, PARAMETER :: lk_asminc = .TRUE. !: Logical switch for assimilation increment interface
56	#else
57	LOGICAL, PUBLIC, PARAMETER :: lk_asminc = .FALSE. !: No assimilation increments
58	#endif
59	LOGICAL, PUBLIC :: ln_bkgwri = .FALSE. !: No output of the background state fields
60	LOGICAL, PUBLIC :: ln_asmiau = .FALSE. !: No applying forcing with an assimilation increment
61	LOGICAL, PUBLIC :: ln_asmdin = .FALSE. !: No direct initialization
62	LOGICAL, PUBLIC :: ln_trainc = .FALSE. !: No tracer (T and S) assimilation increments
63	LOGICAL, PUBLIC :: ln_dyninc = .FALSE. !: No dynamics (u and v) assimilation increments
64	LOGICAL, PUBLIC :: ln_sshinc = .FALSE. !: No sea surface height assimilation increment
65	LOGICAL, PUBLIC :: ln_seaiceinc = .FALSE. !: No sea ice concentration increment
66	LOGICAL, PUBLIC :: ln_salfix = .FALSE. !: Apply minimum salinity check
67	LOGICAL, PUBLIC :: ln_temnofreeze = .FALSE. !: Don't allow the temperature to drop below freezing
68	INTEGER, PUBLIC :: nn_divdmp = 0 !: Apply divergence damping filter nn_divdmp times
69
70	REAL(wp), PUBLIC, DIMENSION(:,:,:), ALLOCATABLE :: t_bkg , s_bkg !: Background temperature and salinity
71	REAL(wp), PUBLIC, DIMENSION(:,:,:), ALLOCATABLE :: u_bkg , v_bkg !: Background u- & v- velocity components
72	REAL(wp), PUBLIC, DIMENSION(:,:,:), ALLOCATABLE :: t_bkginc, s_bkginc !: Increment to the background T & S
73	REAL(wp), PUBLIC, DIMENSION(:,:,:), ALLOCATABLE :: u_bkginc, v_bkginc !: Increment to the u- & v-components
74	REAL(wp), PUBLIC, DIMENSION(:) , ALLOCATABLE :: wgtiau !: IAU weights for each time step
75	#if defined key_asminc
76	REAL(wp), PUBLIC, DIMENSION(:,:), ALLOCATABLE :: ssh_iau !: IAU-weighted sea surface height increment
77	#endif
78	! !!! time steps relative to the cycle interval [0,nitend-nit000-1]
79	INTEGER , PUBLIC :: nitbkg !: Time step of the background state used in the Jb term
80	INTEGER , PUBLIC :: nitdin !: Time step of the background state for direct initialization
81	INTEGER , PUBLIC :: nitiaustr !: Time step of the start of the IAU interval
82	INTEGER , PUBLIC :: nitiaufin !: Time step of the end of the IAU interval
83	!
84	INTEGER , PUBLIC :: niaufn !: Type of IAU weighing function: = 0 Constant weighting
85	! !: = 1 Linear hat-like, centred in middle of IAU interval
86	REAL(wp), PUBLIC :: salfixmin !: Ensure that the salinity is larger than this value if (ln_salfix)
87
88	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: ssh_bkg, ssh_bkginc ! Background sea surface height and its increment
89	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: seaice_bkginc ! Increment to the background sea ice conc
90
91	!! * Substitutions
92	# include "domzgr_substitute.h90"
93	# include "ldfdyn_substitute.h90"
94	# include "vectopt_loop_substitute.h90"
95
96	!!----------------------------------------------------------------------
97	!! NEMO/OPA 3.3 , NEMO Consortium (2010)
98	!! $Id$
99	!! Software governed by the CeCILL licence (NEMOGCM/NEMO_CeCILL.txt)
100	!!----------------------------------------------------------------------
101	CONTAINS
102
103	SUBROUTINE asm_inc_rea_nam
104	NAMELIST/nam_asminc/ ln_bkgwri, &
105	& ln_trainc, ln_dyninc, ln_sshinc, &
106	& ln_asmdin, ln_asmiau, &
107	& nitbkg, nitdin, nitiaustr, nitiaufin, niaufn, &
108	& ln_salfix, salfixmin, &
109	& nn_divdmp
110	!!----------------------------------------------------------------------
111
112	!-----------------------------------------------------------------------
113	! Read Namelist nam_asminc : assimilation increment interface
114	!-----------------------------------------------------------------------
115
116	! Set default values
117	ln_bkgwri = .FALSE.
118	ln_trainc = .FALSE.
119	ln_dyninc = .FALSE.
120	ln_sshinc = .FALSE.
121	ln_seaiceinc = .FALSE.
122	ln_asmdin = .FALSE.
123	ln_asmiau = .TRUE.
124	ln_salfix = .FALSE.
125	ln_temnofreeze = .FALSE.
126	salfixmin = -9999
127	nitbkg = 0
128	nitdin = 0
129	nitiaustr = 1
130	nitiaufin = 150 ! = 10 days with ORCA2
131	niaufn = 0
132
133	REWIND ( numnam )
134	READ ( numnam, nam_asminc )
135
136	! Control print
137	IF(lwp) THEN
138	WRITE(numout,*)
139	WRITE(numout,*) 'asm_inc_init : Assimilation increment initialization :'
140	WRITE(numout,*) '~~~~~~~~~~~~'
141	WRITE(numout,*) ' Namelist namasm : set assimilation increment parameters'
142	WRITE(numout,*) ' Logical switch for writing out background state ln_bkgwri = ', ln_bkgwri
143	WRITE(numout,*) ' Logical switch for applying tracer increments ln_trainc = ', ln_trainc
144	WRITE(numout,*) ' Logical switch for applying velocity increments ln_dyninc = ', ln_dyninc
145	WRITE(numout,*) ' Logical switch for applying SSH increments ln_sshinc = ', ln_sshinc
146	WRITE(numout,*) ' Logical switch for Direct Initialization (DI) ln_asmdin = ', ln_asmdin
147	WRITE(numout,*) ' Logical switch for applying sea ice increments ln_seaiceinc = ', ln_seaiceinc
148	WRITE(numout,*) ' Logical switch for Incremental Analysis Updating (IAU) ln_asmiau = ', ln_asmiau
149	WRITE(numout,*) ' Timestep of background in [0,nitend-nit000-1] nitbkg = ', nitbkg
150	WRITE(numout,*) ' Timestep of background for DI in [0,nitend-nit000-1] nitdin = ', nitdin
151	WRITE(numout,*) ' Timestep of start of IAU interval in [0,nitend-nit000-1] nitiaustr = ', nitiaustr
152	WRITE(numout,*) ' Timestep of end of IAU interval in [0,nitend-nit000-1] nitiaufin = ', nitiaufin
153	WRITE(numout,*) ' Type of IAU weighting function niaufn = ', niaufn
154	WRITE(numout,*) ' Logical switch for ensuring that the sa > salfixmin ln_salfix = ', ln_salfix
155	WRITE(numout,*) ' Minimum salinity after applying the increments salfixmin = ', salfixmin
156	ENDIF
157	END SUBROUTINE
158
159	SUBROUTINE asm_inc_init
160	!!----------------------------------------------------------------------
161	!! * ROUTINE asm_inc_init *
162	!!
163	!! ** Purpose : Initialize the assimilation increment and IAU weights.
164	!!
165	!! ** Method : Initialize the assimilation increment and IAU weights.
166	!!
167	!! ** Action :
168	!!----------------------------------------------------------------------
169	!!
170	!!
171	INTEGER :: ji,jj,jk
172	INTEGER :: jt
173	INTEGER :: imid
174	INTEGER :: inum
175	INTEGER :: iiauper ! Number of time steps in the IAU period
176	INTEGER :: icycper ! Number of time steps in the cycle
177	INTEGER :: iitend_date ! Date YYYYMMDD of final time step
178	INTEGER :: iitbkg_date ! Date YYYYMMDD of background time step for Jb term
179	INTEGER :: iitdin_date ! Date YYYYMMDD of background time step for DI
180	INTEGER :: iitiaustr_date ! Date YYYYMMDD of IAU interval start time step
181	INTEGER :: iitiaufin_date ! Date YYYYMMDD of IAU interval final time step
182
183	REAL(wp) :: znorm ! Normalization factor for IAU weights
184	REAL(wp) :: ztotwgt ! Value of time-integrated IAU weights
185	! (should be equal to one)
186	REAL(wp) :: z_inc_dateb ! Start date of interval on which increment is valid
187	REAL(wp) :: z_inc_datef ! End date of interval on which increment is valid
188	REAL(wp) :: zdate_bkg ! Date in background state file for DI
189	REAL(wp) :: zdate_inc ! Time axis in increments file
190
191	REAL(wp), POINTER, DIMENSION(:,:) :: hdiv
192	!!
193
194	nitbkg_r = nitbkg + nit000 - 1 ! Background time referenced to nit000
195	nitdin_r = nitdin + nit000 - 1 ! Background time for DI referenced to nit000
196	nitiaustr_r = nitiaustr + nit000 - 1 ! Start of IAU interval referenced to nit000
197	nitiaufin_r = nitiaufin + nit000 - 1 ! End of IAU interval referenced to nit000
198
199	iiauper = nitiaufin_r - nitiaustr_r + 1 ! IAU interval length
200	icycper = nitend - nit000 + 1 ! Cycle interval length
201
202	! Date of final time step
203	CALL calc_date( nit000, nitend, ndate0, iitend_date )
204
205	! Background time for Jb referenced to ndate0
206	CALL calc_date( nit000, nitbkg_r, ndate0, iitbkg_date )
207
208	! Background time for DI referenced to ndate0
209	CALL calc_date( nit000, nitdin_r, ndate0, iitdin_date )
210
211	! IAU start time referenced to ndate0
212	CALL calc_date( nit000, nitiaustr_r, ndate0, iitiaustr_date )
213
214	! IAU end time referenced to ndate0
215	CALL calc_date( nit000, nitiaufin_r, ndate0, iitiaufin_date )
216
217	IF(lwp) THEN
218	WRITE(numout,*)
219	WRITE(numout,*) ' Time steps referenced to current cycle:'
220	WRITE(numout,*) ' iitrst = ', nit000 - 1
221	WRITE(numout,*) ' nit000 = ', nit000
222	WRITE(numout,*) ' nitend = ', nitend
223	WRITE(numout,*) ' nitbkg_r = ', nitbkg_r
224	WRITE(numout,*) ' nitdin_r = ', nitdin_r
225	WRITE(numout,*) ' nitiaustr_r = ', nitiaustr_r
226	WRITE(numout,*) ' nitiaufin_r = ', nitiaufin_r
227	WRITE(numout,*)
228	WRITE(numout,*) ' Dates referenced to current cycle:'
229	WRITE(numout,*) ' ndastp = ', ndastp
230	WRITE(numout,*) ' ndate0 = ', ndate0
231	WRITE(numout,*) ' iitend_date = ', iitend_date
232	WRITE(numout,*) ' iitbkg_date = ', iitbkg_date
233	WRITE(numout,*) ' iitdin_date = ', iitdin_date
234	WRITE(numout,*) ' iitiaustr_date = ', iitiaustr_date
235	WRITE(numout,*) ' iitiaufin_date = ', iitiaufin_date
236	ENDIF
237
238	IF ( nacc /= 0 ) &
239	& CALL ctl_stop( ' nacc /= 0 and key_asminc :', &
240	& ' Assimilation increments have only been implemented', &
241	& ' for synchronous time stepping' )
242
243	IF ( ( ln_asmdin ).AND.( ln_asmiau ) ) &
244	& CALL ctl_stop( ' ln_asmdin and ln_asmiau :', &
245	& ' Choose Direct Initialization OR Incremental Analysis Updating')
246
247	IF ( ( ( .NOT. ln_asmdin ).AND.( .NOT. ln_asmiau ) ) &
248	.AND.( ( ln_trainc ).OR.( ln_dyninc ).OR.( ln_sshinc ) .OR. ( ln_seaiceinc) )) &
249	& CALL ctl_stop( ' One or more of ln_trainc, ln_dyninc, ln_sshinc and ln_seaiceinc is set to .true.', &
250	& ' but ln_asmdin and ln_asmiau are both set to .false. :', &
251	& ' Inconsistent options')
252
253	IF ( ( ln_bkgwri ).AND.( ( ln_asmdin ).OR.( ln_asmiau ) ) ) &
254	& CALL ctl_stop( ' ln_bkgwri and either ln_asmdin or ln_asmiau are set to .true.:', &
255	& ' The background state must be written before applying the increments')
256
257	IF ( ( niaufn /= 0 ).AND.( niaufn /= 1 ) ) &
258	& CALL ctl_stop( ' niaufn /= 0 or niaufn /=1 :', &
259	& ' Type IAU weighting function is invalid')
260
261	IF ( ( .NOT. ln_trainc ).AND.( .NOT. ln_dyninc ).AND.( .NOT. ln_sshinc ).AND.( .NOT. ln_seaiceinc ) &
262	& ) &
263	& CALL ctl_warn( ' ln_trainc, ln_dyninc, ln_sshinc and ln_seaiceinc are set to .false. :', &
264	& ' The assimilation increments are not applied')
265
266	IF ( ( ln_asmiau ).AND.( nitiaustr == nitiaufin ) ) &
267	& CALL ctl_stop( ' nitiaustr = nitiaufin :', &
268	& ' IAU interval is of zero length')
269
270	IF ( ( ln_asmiau ).AND.( ( nitiaustr_r < nit000 ).OR.( nitiaufin_r > nitend ) ) ) &
271	& CALL ctl_stop( ' nitiaustr or nitiaufin :', &
272	& ' IAU starting or final time step is outside the cycle interval', &
273	& ' Valid range nit000 to nitend')
274
275	IF ( ( nitbkg_r < nit000 - 1 ).OR.( nitbkg_r > nitend ) ) &
276	& CALL ctl_stop( ' nitbkg :', &
277	& ' Background time step is outside the cycle interval')
278
279	IF ( ( nitdin_r < nit000 - 1 ).OR.( nitdin_r > nitend ) ) &
280	& CALL ctl_stop( ' nitdin :', &
281	& ' Background time step for Direct Initialization is outside', &
282	& ' the cycle interval')
283
284	IF ( nstop > 0 ) RETURN ! if there are any errors then go no further
285
286	!--------------------------------------------------------------------
287	! Initialize the Incremental Analysis Updating weighting function
288	!--------------------------------------------------------------------
289
290	IF ( ln_asmiau ) THEN
291
292	ALLOCATE( wgtiau( icycper ) )
293
294	wgtiau(:) = 0.0
295
296	IF ( niaufn == 0 ) THEN
297
298	!---------------------------------------------------------
299	! Constant IAU forcing
300	!---------------------------------------------------------
301
302	DO jt = 1, iiauper
303	wgtiau(jt+nitiaustr-1) = 1.0 / REAL( iiauper )
304	END DO
305
306	ELSEIF ( niaufn == 1 ) THEN
307
308	!---------------------------------------------------------
309	! Linear hat-like, centred in middle of IAU interval
310	!---------------------------------------------------------
311
312	! Compute the normalization factor
313	znorm = 0.0
314	IF ( MOD( iiauper, 2 ) == 0 ) THEN ! Even number of time steps in IAU interval
315	imid = iiauper / 2
316	DO jt = 1, imid
317	znorm = znorm + REAL( jt )
318	END DO
319	znorm = 2.0 * znorm
320	ELSE ! Odd number of time steps in IAU interval
321	imid = ( iiauper + 1 ) / 2
322	DO jt = 1, imid - 1
323	znorm = znorm + REAL( jt )
324	END DO
325	znorm = 2.0 * znorm + REAL( imid )
326	ENDIF
327	znorm = 1.0 / znorm
328
329	DO jt = 1, imid - 1
330	wgtiau(jt+nitiaustr-1) = REAL( jt ) * znorm
331	END DO
332	DO jt = imid, iiauper
333	wgtiau(jt+nitiaustr-1) = REAL( iiauper - jt + 1 ) * znorm
334	END DO
335
336	ENDIF
337
338	! Test that the integral of the weights over the weighting interval equals 1
339	IF(lwp) THEN
340	WRITE(numout,*)
341	WRITE(numout,*) 'asm_inc_init : IAU weights'
342	WRITE(numout,*) '~~~~~~~~~~~~'
343	WRITE(numout,*) ' time step IAU weight'
344	WRITE(numout,*) ' ========= ====================='
345	ztotwgt = 0.0
346	DO jt = 1, icycper
347	ztotwgt = ztotwgt + wgtiau(jt)
348	WRITE(numout,*) ' ', jt, ' ', wgtiau(jt)
349	END DO
350	WRITE(numout,*) ' ==================================='
351	WRITE(numout,*) ' Time-integrated weight = ', ztotwgt
352	WRITE(numout,*) ' ==================================='
353	ENDIF
354
355	ENDIF
356
357	!--------------------------------------------------------------------
358	! Allocate and initialize the increment arrays
359	!--------------------------------------------------------------------
360
361	ALLOCATE( t_bkginc(jpi,jpj,jpk) )
362	ALLOCATE( s_bkginc(jpi,jpj,jpk) )
363	ALLOCATE( u_bkginc(jpi,jpj,jpk) )
364	ALLOCATE( v_bkginc(jpi,jpj,jpk) )
365	ALLOCATE( ssh_bkginc(jpi,jpj) )
366	ALLOCATE( seaice_bkginc(jpi,jpj))
367	#if defined key_asminc
368	ALLOCATE( ssh_iau(jpi,jpj) )
369	#endif
370	t_bkginc(:,:,:) = 0.0
371	s_bkginc(:,:,:) = 0.0
372	u_bkginc(:,:,:) = 0.0
373	v_bkginc(:,:,:) = 0.0
374	ssh_bkginc(:,:) = 0.0
375	seaice_bkginc(:,:) = 0.0
376	#if defined key_asminc
377	ssh_iau(:,:) = 0.0
378	#endif
379	IF ( ( ln_trainc ).OR.( ln_dyninc ).OR.( ln_sshinc ).OR.( ln_seaiceinc ) ) THEN
380
381	!--------------------------------------------------------------------
382	! Read the increments from file
383	!--------------------------------------------------------------------
384
385	CALL iom_open( c_asminc, inum )
386
387	CALL iom_get( inum, 'time', zdate_inc )
388
389	CALL iom_get( inum, 'z_inc_dateb', z_inc_dateb )
390	CALL iom_get( inum, 'z_inc_datef', z_inc_datef )
391	z_inc_dateb = zdate_inc
392	z_inc_datef = zdate_inc
393
394	IF(lwp) THEN
395	WRITE(numout,*)
396	WRITE(numout,*) 'asm_inc_init : Assimilation increments valid ', &
397	& ' between dates ', NINT( z_inc_dateb ),' and ', &
398	& NINT( z_inc_datef )
399	WRITE(numout,*) '~~~~~~~~~~~~'
400	ENDIF
401
402	IF ( ( NINT( z_inc_dateb ) < ndastp ) &
403	& .OR.( NINT( z_inc_datef ) > iitend_date ) ) &
404	& CALL ctl_warn( ' Validity time of assimilation increments is ', &
405	& ' outside the assimilation interval' )
406
407	IF ( ( ln_asmdin ).AND.( NINT( zdate_inc ) /= iitdin_date ) ) &
408	& CALL ctl_warn( ' Validity time of assimilation increments does ', &
409	& ' not agree with Direct Initialization time' )
410
411	IF ( ln_trainc ) THEN
412	CALL iom_get( inum, jpdom_autoglo, 'bckint', t_bkginc, 1 )
413	CALL iom_get( inum, jpdom_autoglo, 'bckins', s_bkginc, 1 )
414	! Apply the masks
415	t_bkginc(:,:,:) = t_bkginc(:,:,:) * tmask(:,:,:)
416	s_bkginc(:,:,:) = s_bkginc(:,:,:) * tmask(:,:,:)
417	! Set missing increments to 0.0 rather than 1e+20
418	! to allow for differences in masks
419	WHERE( ABS( t_bkginc(:,:,:) ) > 1.0e+10 ) t_bkginc(:,:,:) = 0.0
420	WHERE( ABS( s_bkginc(:,:,:) ) > 1.0e+10 ) s_bkginc(:,:,:) = 0.0
421	ENDIF
422
423	IF ( ln_dyninc ) THEN
424	CALL iom_get( inum, jpdom_autoglo, 'bckinu', u_bkginc, 1 )
425	CALL iom_get( inum, jpdom_autoglo, 'bckinv', v_bkginc, 1 )
426	! Apply the masks
427	u_bkginc(:,:,:) = u_bkginc(:,:,:) * umask(:,:,:)
428	v_bkginc(:,:,:) = v_bkginc(:,:,:) * vmask(:,:,:)
429	! Set missing increments to 0.0 rather than 1e+20
430	! to allow for differences in masks
431	WHERE( ABS( u_bkginc(:,:,:) ) > 1.0e+10 ) u_bkginc(:,:,:) = 0.0
432	WHERE( ABS( v_bkginc(:,:,:) ) > 1.0e+10 ) v_bkginc(:,:,:) = 0.0
433	ENDIF
434
435	IF ( ln_sshinc ) THEN
436	CALL iom_get( inum, jpdom_autoglo, 'bckineta', ssh_bkginc, 1 )
437	! Apply the masks
438	ssh_bkginc(:,:) = ssh_bkginc(:,:) * tmask(:,:,1)
439	! Set missing increments to 0.0 rather than 1e+20
440	! to allow for differences in masks
441	WHERE( ABS( ssh_bkginc(:,:) ) > 1.0e+10 ) ssh_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	#if defined key_cice
692	fzptnz(:,:,:) = -1.8_wp
693	#else
694	DO jk = 1, jpk
695	DO jj = 1, jpj
696	DO ji = 1, jpk
697	fzptnz (ji,jj,jk) = ( -0.0575_wp + 1.710523e-3_wp * SQRT( tsn(ji,jj,jk,jp_sal) ) &
698	- 2.154996e-4_wp * tsn(ji,jj,jk,jp_sal) ) * tsn(ji,jj,jk,jp_sal) &
699	- 7.53e-4_wp * fsdepw(ji,jj,jk) ! (pressure in dbar)
700	END DO
701	END DO
702	END DO
703	#endif
704
705	IF ( ln_asmiau ) THEN
706
707	!--------------------------------------------------------------------
708	! Incremental Analysis Updating
709	!--------------------------------------------------------------------
710
711	IF ( ( kt >= nitiaustr_r ).AND.( kt <= nitiaufin_r ) ) THEN
712
713	it = kt - nit000 + 1
714	zincwgt = wgtiau(it) / rdt ! IAU weight for the current time step
715
716	IF(lwp) THEN
717	WRITE(numout,*)
718	WRITE(numout,*) 'tra_asm_inc : Tracer IAU at time step = ', &
719	& kt,' with IAU weight = ', wgtiau(it)
720	WRITE(numout,*) '~~~~~~~~~~~~'
721	ENDIF
722
723	! Update the tracer tendencies
724	DO jk = 1, jpkm1
725	IF (ln_temnofreeze) THEN
726	! Do not apply negative increments if the temperature will fall below freezing
727	WHERE(t_bkginc(:,:,jk) > 0.0_wp .OR. &
728	& t_bkg(:,:,jk) + tsa(:,:,jk,jp_tem) + t_bkginc(:,:,jk) * wgtiau(it) > fzptnz(:,:,jk) )
729	tsa(:,:,jk,jp_tem) = tsa(:,:,jk,jp_tem) + t_bkginc(:,:,jk) * zincwgt
730	END WHERE
731	ELSE
732	tsa(:,:,jk,jp_tem) = tsa(:,:,jk,jp_tem) + t_bkginc(:,:,jk) * zincwgt
733	ENDIF
734	IF (ln_salfix) THEN
735	! Do not apply negative increments if the salinity will fall below a specified
736	! minimum value salfixmin
737	WHERE(s_bkginc(:,:,jk) > 0.0_wp .OR. &
738	& s_bkg(:,:,jk) + tsa(:,:,jk,jp_sal) + s_bkginc(:,:,jk) * wgtiau(it) > salfixmin )
739	tsa(:,:,jk,jp_sal) = tsa(:,:,jk,jp_sal) + s_bkginc(:,:,jk) * zincwgt
740	END WHERE
741	ELSE
742	tsa(:,:,jk,jp_sal) = tsa(:,:,jk,jp_sal) + s_bkginc(:,:,jk) * zincwgt
743	ENDIF
744	END DO
745
746	ENDIF
747
748	IF ( kt == nitiaufin_r + 1 ) THEN ! For bias crcn to work
749	DEALLOCATE( t_bkginc )
750	DEALLOCATE( s_bkginc )
751	ENDIF
752
753
754	ELSEIF ( ln_asmdin ) THEN
755
756	!--------------------------------------------------------------------
757	! Direct Initialization
758	!--------------------------------------------------------------------
759
760	IF ( kt == nitdin_r ) THEN
761
762	neuler = 0 ! Force Euler forward step
763
764	! Initialize the now fields with the background + increment
765	IF (ln_temnofreeze) THEN
766	! Do not apply negative increments if the temperature will fall below freezing
767	WHERE(t_bkginc(:,:,:) > 0.0_wp .OR. &
768	& tsn(:,:,:,jp_tem) + t_bkginc(:,:,:) > fzptnz(:,:,:) )
769	tsn(:,:,:,jp_tem) = t_bkg(:,:,:) + t_bkginc(:,:,:)
770	END WHERE
771	ELSE
772	tsn(:,:,:,jp_tem) = t_bkg(:,:,:) + t_bkginc(:,:,:)
773	ENDIF
774	IF (ln_salfix) THEN
775	! Do not apply negative increments if the salinity will fall below a specified
776	! minimum value salfixmin
777	WHERE(s_bkginc(:,:,:) > 0.0_wp .OR. &
778	& tsn(:,:,:,jp_sal) + s_bkginc(:,:,:) > salfixmin )
779	tsn(:,:,:,jp_sal) = s_bkg(:,:,:) + s_bkginc(:,:,:)
780	END WHERE
781	ELSE
782	tsn(:,:,:,jp_sal) = s_bkg(:,:,:) + s_bkginc(:,:,:)
783	ENDIF
784
785	tsb(:,:,:,:) = tsn(:,:,:,:) ! Update before fields
786
787	CALL eos( tsb, rhd, rhop ) ! Before potential and in situ densities
788
789	IF( ln_zps .AND. .NOT. lk_c1d ) &
790	& CALL zps_hde( nit000, jpts, tsb, & ! Partial steps: before horizontal derivative
791	& gtsu, gtsv, rhd, & ! of T, S, rd at the bottom ocean level
792	& gru , grv )
793
794	#if defined key_zdfkpp
795	CALL eos( tsn, rhd ) ! Compute rhd
796	#endif
797
798	DEALLOCATE( t_bkginc )
799	DEALLOCATE( s_bkginc )
800	DEALLOCATE( t_bkg )
801	DEALLOCATE( s_bkg )
802	ENDIF
803	!
804	ENDIF
805	! Perhaps the following call should be in step
806	IF ( ln_seaiceinc ) CALL seaice_asm_inc ( kt ) ! apply sea ice concentration increment
807	!
808	END SUBROUTINE tra_asm_inc
809
810
811	SUBROUTINE dyn_asm_inc( kt )
812	!!----------------------------------------------------------------------
813	!! * ROUTINE dyn_asm_inc *
814	!!
815	!! ** Purpose : Apply the dynamics (u and v) assimilation increments.
816	!!
817	!! ** Method : Direct initialization or Incremental Analysis Updating.
818	!!
819	!! ** Action :
820	!!----------------------------------------------------------------------
821	INTEGER, INTENT(IN) :: kt ! Current time step
822	!
823	INTEGER :: jk
824	INTEGER :: it
825	REAL(wp) :: zincwgt ! IAU weight for current time step
826	!!----------------------------------------------------------------------
827
828	IF ( ln_asmiau ) THEN
829
830	!--------------------------------------------------------------------
831	! Incremental Analysis Updating
832	!--------------------------------------------------------------------
833
834	IF ( ( kt >= nitiaustr_r ).AND.( kt <= nitiaufin_r ) ) THEN
835
836	it = kt - nit000 + 1
837	zincwgt = wgtiau(it) / rdt ! IAU weight for the current time step
838
839	IF(lwp) THEN
840	WRITE(numout,*)
841	WRITE(numout,*) 'dyn_asm_inc : Dynamics IAU at time step = ', &
842	& kt,' with IAU weight = ', wgtiau(it)
843	WRITE(numout,*) '~~~~~~~~~~~~'
844	ENDIF
845
846	! Update the dynamic tendencies
847	DO jk = 1, jpkm1
848	ua(:,:,jk) = ua(:,:,jk) + u_bkginc(:,:,jk) * zincwgt
849	va(:,:,jk) = va(:,:,jk) + v_bkginc(:,:,jk) * zincwgt
850	END DO
851
852	IF ( kt == nitiaufin_r ) THEN
853	DEALLOCATE( u_bkginc )
854	DEALLOCATE( v_bkginc )
855	ENDIF
856
857	ENDIF
858
859	ELSEIF ( ln_asmdin ) THEN
860
861	!--------------------------------------------------------------------
862	! Direct Initialization
863	!--------------------------------------------------------------------
864
865	IF ( kt == nitdin_r ) THEN
866
867	neuler = 0 ! Force Euler forward step
868
869	! Initialize the now fields with the background + increment
870	un(:,:,:) = u_bkg(:,:,:) + u_bkginc(:,:,:)
871	vn(:,:,:) = v_bkg(:,:,:) + v_bkginc(:,:,:)
872
873	ub(:,:,:) = un(:,:,:) ! Update before fields
874	vb(:,:,:) = vn(:,:,:)
875
876	DEALLOCATE( u_bkg )
877	DEALLOCATE( v_bkg )
878	DEALLOCATE( u_bkginc )
879	DEALLOCATE( v_bkginc )
880	ENDIF
881	!
882	ENDIF
883	!
884	END SUBROUTINE dyn_asm_inc
885
886
887	SUBROUTINE ssh_asm_inc( kt )
888	!!----------------------------------------------------------------------
889	!! * ROUTINE ssh_asm_inc *
890	!!
891	!! ** Purpose : Apply the sea surface height assimilation increment.
892	!!
893	!! ** Method : Direct initialization or Incremental Analysis Updating.
894	!!
895	!! ** Action :
896	!!----------------------------------------------------------------------
897	INTEGER, INTENT(IN) :: kt ! Current time step
898	!
899	INTEGER :: it
900	INTEGER :: jk
901	REAL(wp) :: zincwgt ! IAU weight for current time step
902	!!----------------------------------------------------------------------
903
904	IF ( ln_asmiau ) THEN
905
906	!--------------------------------------------------------------------
907	! Incremental Analysis Updating
908	!--------------------------------------------------------------------
909
910	IF ( ( kt >= nitiaustr_r ).AND.( kt <= nitiaufin_r ) ) THEN
911
912	it = kt - nit000 + 1
913	zincwgt = wgtiau(it) / rdt ! IAU weight for the current time step
914
915	IF(lwp) THEN
916	WRITE(numout,*)
917	WRITE(numout,*) 'ssh_asm_inc : SSH IAU at time step = ', &
918	& kt,' with IAU weight = ', wgtiau(it)
919	WRITE(numout,*) '~~~~~~~~~~~~'
920	ENDIF
921
922	! Save the tendency associated with the IAU weighted SSH increment
923	! (applied in dynspg.*)
924	#if defined key_asminc
925	ssh_iau(:,:) = ssh_bkginc(:,:) * zincwgt
926	#endif
927	IF ( kt == nitiaufin_r ) THEN
928	DEALLOCATE( ssh_bkginc )
929	ENDIF
930
931	ENDIF
932
933	ELSEIF ( ln_asmdin ) THEN
934
935	!--------------------------------------------------------------------
936	! Direct Initialization
937	!--------------------------------------------------------------------
938
939	IF ( kt == nitdin_r ) THEN
940
941	neuler = 0 ! Force Euler forward step
942
943	! Initialize the now fields the background + increment
944	sshn(:,:) = ssh_bkg(:,:) + ssh_bkginc(:,:)
945
946	! Update before fields
947	sshb(:,:) = sshn(:,:)
948
949	IF( lk_vvl ) THEN
950	DO jk = 1, jpk
951	fse3t_b(:,:,jk) = fse3t_n(:,:,jk)
952	END DO
953	ENDIF
954
955	DEALLOCATE( ssh_bkg )
956	DEALLOCATE( ssh_bkginc )
957
958	ENDIF
959	!
960	ENDIF
961	!
962	END SUBROUTINE ssh_asm_inc
963
964	SUBROUTINE seaice_asm_inc( kt, kindic )
965	!!----------------------------------------------------------------------
966	!! * ROUTINE seaice_asm_inc *
967	!!
968	!! ** Purpose : Apply the sea ice assimilation increment.
969	!!
970	!! ** Method : Direct initialization or Incremental Analysis Updating.
971	!!
972	!! ** Action :
973	!!
974	!! History :
975	!! ! 07-2011 (D. Lea) Initial version based on ssh_asm_inc
976	!!----------------------------------------------------------------------
977
978	IMPLICIT NONE
979
980	!! * Arguments
981	INTEGER, INTENT(IN) :: kt ! Current time step
982	INTEGER, OPTIONAL, INTENT(IN) :: kindic ! flag for disabling the deallocation
983
984	!! * Local declarations
985	INTEGER :: it
986	REAL(wp) :: zincwgt ! IAU weight for current time step
987
988	#if defined key_lim2
989	REAL(wp), DIMENSION(jpi,jpj) :: zofrld, zohicif, zseaicendg, zhicifinc ! LIM
990	REAL(wp) :: zhicifmin=0.5_wp ! ice minimum depth in metres
991
992	#endif
993
994
995	IF ( ln_asmiau ) THEN
996
997	!--------------------------------------------------------------------
998	! Incremental Analysis Updating
999	!--------------------------------------------------------------------
1000
1001	IF ( ( kt >= nitiaustr_r ).AND.( kt <= nitiaufin_r ) ) THEN
1002
1003	it = kt - nit000 + 1
1004	zincwgt = wgtiau(it) ! IAU weight for the current time step
1005	! note this is not a tendency so should not be divided by rdt (as with the tracer and other increments)
1006
1007	IF(lwp) THEN
1008	WRITE(numout,*)
1009	WRITE(numout,*) 'seaice_asm_inc : sea ice conc IAU at time step = ', &
1010	& kt,' with IAU weight = ', wgtiau(it)
1011	WRITE(numout,*) '~~~~~~~~~~~~'
1012	ENDIF
1013
1014	#if defined key_lim2
1015
1016	zofrld(:,:)=frld(:,:)
1017	zohicif(:,:)=hicif(:,:)
1018
1019	frld = MIN( MAX( frld(:,:) - seaice_bkginc(:,:) * zincwgt, 0.0_wp), 1.0_wp)
1020	pfrld = MIN( MAX( pfrld(:,:) - seaice_bkginc(:,:) * zincwgt, 0.0_wp), 1.0_wp)
1021	fr_i(:,:) = 1.0_wp - frld(:,:) ! adjust ice fraction
1022
1023	zseaicendg(:,:)=zofrld(:,:) - frld(:,:) ! find out actual sea ice nudge applied
1024
1025	! Nudge sea ice depth to bring it up to a required minimum depth
1026
1027	WHERE( zseaicendg(:,:) > 0.0_wp .AND. hicif(:,:) < zhicifmin )
1028	zhicifinc(:,:) = (zhicifmin - hicif(:,:)) * zincwgt
1029	ELSEWHERE
1030	zhicifinc(:,:) = 0.0_wp
1031	END WHERE
1032
1033	! nudge ice depth
1034	hicif(:,:)=hicif(:,:) + zhicifinc(:,:)
1035	phicif(:,:)=phicif(:,:) + zhicifinc(:,:)
1036
1037	! seaice salinity balancing (to add)
1038
1039	#endif
1040
1041	#if defined key_cice
1042
1043	! Pass ice increment tendency into CICE
1044	ndaice_da(:,:) = seaice_bkginc(:,:) * zincwgt / rdt
1045
1046	#endif
1047
1048	IF ( kt == nitiaufin_r ) THEN
1049	DEALLOCATE( seaice_bkginc )
1050	ENDIF
1051
1052	ELSE
1053
1054	#if defined key_cice
1055
1056	! Zero ice increment tendency into CICE
1057	ndaice_da(:,:) = 0.0_wp
1058
1059	#endif
1060
1061	ENDIF
1062
1063	ELSEIF ( ln_asmdin ) THEN
1064
1065	!--------------------------------------------------------------------
1066	! Direct Initialization
1067	!--------------------------------------------------------------------
1068
1069	IF ( kt == nitdin_r ) THEN
1070
1071	neuler = 0 ! Force Euler forward step
1072
1073	#if defined key_lim2
1074
1075	zofrld(:,:)=frld(:,:)
1076	zohicif(:,:)=hicif(:,:)
1077
1078	! Initialize the now fields the background + increment
1079
1080	frld(:,:) = MIN( MAX( frld(:,:) - seaice_bkginc(:,:), 0.0_wp), 1.0_wp)
1081	pfrld(:,:) = frld(:,:)
1082	fr_i(:,:) = 1.0_wp - frld(:,:) ! adjust ice fraction
1083
1084	zseaicendg(:,:)=zofrld(:,:) - frld(:,:) ! find out actual sea ice nudge applied
1085
1086	! Nudge sea ice depth to bring it up to a required minimum depth
1087
1088	WHERE( zseaicendg(:,:) > 0.0_wp .AND. hicif(:,:) < zhicifmin )
1089	zhicifinc(:,:) = (zhicifmin - hicif(:,:)) * zincwgt
1090	ELSEWHERE
1091	zhicifinc(:,:) = 0.0_wp
1092	END WHERE
1093
1094	! nudge ice depth
1095	hicif(:,:)=hicif(:,:) + zhicifinc(:,:)
1096	phicif(:,:)=phicif(:,:)
1097
1098	! seaice salinity balancing (to add)
1099
1100	#endif
1101
1102	#if defined key_cice
1103
1104	! Pass ice increment tendency into CICE - is this correct?
1105	ndaice_da(:,:) = seaice_bkginc(:,:) / rdt
1106
1107	#endif
1108	IF ( .NOT. PRESENT(kindic) ) THEN
1109	DEALLOCATE( seaice_bkginc )
1110	END IF
1111
1112	ELSE
1113
1114	#if defined key_cice
1115
1116	! Zero ice increment tendency into CICE
1117	ndaice_da(:,:) = 0.0_wp
1118
1119	#endif
1120
1121	ENDIF
1122
1123	!#if defined key_lim2 \|\| defined key_cice
1124	!
1125	! IF (ln_seaicebal ) THEN
1126	! !! balancing salinity increments
1127	! !! simple case from limflx.F90 (doesn't include a mass flux)
1128	! !! assumption is that as ice concentration is reduced or increased
1129	! !! the snow and ice depths remain constant
1130	! !! note that snow is being created where ice concentration is being increased
1131	! !! - could be more sophisticated and
1132	! !! not do this (but would need to alter h_snow)
1133	!
1134	! usave(:,:,:)=sb(:,:,:) ! use array as a temporary store
1135	!
1136	! DO jj = 1, jpj
1137	! DO ji = 1, jpi
1138	! ! calculate change in ice and snow mass per unit area
1139	! ! positive values imply adding salt to the ocean (results from ice formation)
1140	! ! fwf : ice formation and melting
1141	!
1142	! zfons = ( -nfresh_da(ji,jj)soce + nfsalt_da(ji,jj) )rdt
1143	!
1144	! ! change salinity down to mixed layer depth
1145	! mld=hmld_kara(ji,jj)
1146	!
1147	! ! prevent small mld
1148	! ! less than 10m can cause salinity instability
1149	! IF (mld < 10) mld=10
1150	!
1151	! ! set to bottom of a level
1152	! DO jk = jpk-1, 2, -1
1153	! IF ((mld > gdepw(ji,jj,jk)) .and. (mld < gdepw(ji,jj,jk+1))) THEN
1154	! mld=gdepw(ji,jj,jk+1)
1155	! jkmax=jk
1156	! ENDIF
1157	! ENDDO
1158	!
1159	! ! avoid applying salinity balancing in shallow water or on land
1160	! !
1161	!
1162	! ! dsal_ocn (psu kg m^-2) / (kg m^-3 * m)
1163	!
1164	! dsal_ocn=0.0_wp
1165	! sal_thresh=5.0_wp ! minimum salinity threshold for salinity balancing
1166	!
1167	! if (tmask(ji,jj,1) > 0 .AND. tmask(ji,jj,jkmax) > 0 ) &
1168	! dsal_ocn = zfons / (rhop(ji,jj,1) * mld)
1169	!
1170	! ! put increments in for levels in the mixed layer
1171	! ! but prevent salinity below a threshold value
1172	!
1173	! DO jk = 1, jkmax
1174	!
1175	! IF (dsal_ocn > 0.0_wp .or. sb(ji,jj,jk)+dsal_ocn > sal_thresh) THEN
1176	! sb(ji,jj,jk) = sb(ji,jj,jk) + dsal_ocn
1177	! sn(ji,jj,jk) = sn(ji,jj,jk) + dsal_ocn
1178	! ENDIF
1179	!
1180	! ENDDO
1181	!
1182	! ! ! salt exchanges at the ice/ocean interface
1183	! ! zpmess = zfons / rdt_ice ! rdt_ice is ice timestep
1184	! !
1185	! !! Adjust fsalt. A +ve fsalt means adding salt to ocean
1186	! !! fsalt(ji,jj) = fsalt(ji,jj) + zpmess ! adjust fsalt
1187	! !!
1188	! !! emps(ji,jj) = emps(ji,jj) + zpmess ! or adjust emps (see icestp1d)
1189	! !! ! E-P (kg m-2 s-2)
1190	! ! emp(ji,jj) = emp(ji,jj) + zpmess ! E-P (kg m-2 s-2)
1191	! ENDDO !ji
1192	! ENDDO !jj!
1193	!
1194	! ENDIF !ln_seaicebal
1195	!
1196	!#endif
1197
1198
1199	ENDIF
1200
1201	END SUBROUTINE seaice_asm_inc
1202	!!======================================================================
1203	END MODULE asminc

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