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source: branches/nemo_v3_3_beta/NEMOGCM/NEMO/OPA_SRC/ASM/asminc.F90 @ 2287

Last change on this file since 2287 was 2287, checked in by smasson, 14 years ago
update licence of all NEMO files...
Property svn:keywords set to `Id`
File size: 37.5 KB

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1	MODULE asminc
2	!!======================================================================
3	!! * MODULE asminc *
4	!! Assimilation increment : Apply an increment generated by data
5	!! assimilation
6	!!======================================================================
7
8	!!----------------------------------------------------------------------
9	!! 'key_asminc' : Switch on the assimilation increment interface
10	!!----------------------------------------------------------------------
11	!! asm_inc_init : Initialize the increment arrays and IAU weights
12	!! calc_date : Compute the calendar date YYYYMMDD on a given step
13	!! tra_asm_inc : Apply the tracer (T and S) increments
14	!! dyn_asm_inc : Apply the dynamic (u and v) increments
15	!! ssh_asm_inc : Apply the SSH increment
16	!!----------------------------------------------------------------------
17	!! * Modules used
18	USE par_kind, ONLY : & ! Precision variables
19	& wp
20	USE in_out_manager, ONLY : & ! I/O manager
21	& lwp, &
22	& numnam, &
23	& numout, &
24	& ctl_warn, &
25	& ctl_stop, &
26	& nit000, &
27	& nstop, &
28	& ln_rstart
29	USE par_oce, ONLY : & ! Ocean space and time domain variables
30	& jpi, &
31	& jpj, &
32	& jpk, &
33	& jpkm1
34	USE dom_oce, ONLY : & ! Ocean space and time domain
35	& rdt, &
36	& n_cla, &
37	& neuler, &
38	& ln_zps, &
39	& tmask, &
40	& umask, &
41	& vmask
42	#if defined key_c1d
43	USE c1d, ONLY : & ! 1D initialization
44	& lk_c1d
45	#endif
46	USE oce, ONLY : & ! Dynamics and active tracers defined in memory
47	& ub, un, ua, &
48	& vb, vn, va, &
49	& tsb, tsn, tsa, &
50	& sshb, sshn, &
51	& rhd, rhop, &
52	& rotb, rotn, &
53	& hdivb, hdivn, &
54	& gtsu, gru, &
55	& gtsv, grv
56	USE divcur, ONLY : & ! Horizontal divergence and relative vorticity
57	& div_cur
58	USE cla_div, ONLY : & ! Specific update of the horizontal divergence
59	& div_cla ! (specific to ORCA_R2)
60	USE eosbn2, ONLY : & ! Equation of state - in situ and potential density
61	& eos
62	USE zpshde, ONLY : & ! Partial step : Horizontal Derivative
63	& zps_hde
64	! USE phycst, ONLY : & ! Calendar parameters
65	! & rjjss
66	USE iom ! Library to read input files
67	USE asmpar ! Parameters for the assmilation interface
68	USE dom_oce, ONLY : &
69	& ndastp
70	! USE daymod, ONLY : &
71	! & nmonth_len ! length of month in days
72	! & nbiss, &
73	! & nobis, &
74
75
76	IMPLICIT NONE
77
78	!! * Routine accessibility
79	PRIVATE
80	PUBLIC asm_inc_init, & !: Initialize the increment arrays and IAU weights
81	& calc_date, & !: Compute the calendar date YYYYMMDD on a given step
82	& tra_asm_inc, & !: Apply the tracer (T and S) increments
83	& dyn_asm_inc, & !: Apply the dynamic (u and v) increments
84	& ssh_asm_inc !: Apply the SSH increment
85
86	!! * Private Module variables
87	REAL(wp), PUBLIC, DIMENSION(:,:,:), ALLOCATABLE :: &
88	& t_bkg, & !: Background temperature
89	& s_bkg, & !: Background salinity
90	& u_bkg, & !: Background u-component velocity
91	& v_bkg, & !: Background v-component velocity
92	& t_bkginc, & !: Increment to the background temperature
93	& s_bkginc, & !: Increment to the background salinity
94	& u_bkginc, & !: Increment to the u-component velocity
95	& v_bkginc !: Increment to the v-component velocity
96
97	REAL(wp), PRIVATE, DIMENSION(:,:), ALLOCATABLE :: &
98	& ssh_bkg, & !: Background sea surface height
99	& ssh_bkginc !: Increment to the background sea surface height
100
101	REAL(wp), PUBLIC, DIMENSION(:), ALLOCATABLE :: &
102	& wgtiau !: IAU weights for each time step
103
104	!! * Shared Module variables
105	LOGICAL, PUBLIC, PARAMETER :: &
106	#if defined key_asminc
107	& lk_asminc = .TRUE. !: Logical switch for assimilation increment interface
108	#else
109	& lk_asminc = .FALSE. !: No assimilation increments
110	#endif
111
112	LOGICAL, PUBLIC :: ln_bkgwri = .FALSE. !: No output of the background state fields
113	LOGICAL, PUBLIC :: ln_trjwri = .FALSE. !: No output of the state trajectory fields
114	LOGICAL, PUBLIC :: ln_asmiau = .FALSE. !: No applying forcing with an assimilation increment
115	LOGICAL, PUBLIC :: ln_asmdin = .FALSE. !: No direct initialization
116	LOGICAL, PUBLIC :: ln_trainc = .FALSE. !: No tracer (T and S) assimilation increments
117	LOGICAL, PUBLIC :: ln_dyninc = .FALSE. !: No dynamics (u and v) assimilation increments
118	LOGICAL, PUBLIC :: ln_sshinc = .FALSE. !: No sea surface height assimilation increment
119	LOGICAL, PUBLIC :: ln_salfix = .FALSE. !: Apply minimum salinity check
120
121	REAL, PUBLIC :: salfixmin !: Ensure that the salinity is larger than
122	! !: this value if (ln_salfix)
123	#if defined key_asminc
124	REAL(wp), PUBLIC, DIMENSION(:,:), ALLOCATABLE :: &
125	& ssh_iau !: IAU-weighted sea surface height increment
126	#endif
127
128	INTEGER, PUBLIC :: nitbkg !: Time step of the background state used in the Jb term
129	!: (relative to the cycle interval [0,nitend-nit000-1])
130	INTEGER, PUBLIC :: nitdin !: Time step of the background state for direct initialization
131	!: (relative to the cycle interval [0,nitend-nit000-1])
132	INTEGER, PUBLIC :: nitiaustr !: Time step of the start of the IAU interval
133	!: (relative to the cycle interval [0,nitend-nit000-1])
134	INTEGER, PUBLIC :: nitiaufin !: Time step of the end of the IAU interval
135	!: (relative to the cycle interval [0,nitend-nit000-1])
136	INTEGER, PUBLIC :: niaufn !: Type of IAU weighing function
137	!: 0 = Constant weighting
138	!: 1 = Linear hat-like, centred in middle of IAU interval
139
140	!!----------------------------------------------------------------------
141	!! NEMO/OPA 3.3 , NEMO Consortium (2010)
142	!! $Id$
143	!! Software governed by the CeCILL licence (NEMOGCM/NEMO_CeCILL.txt)
144	!!----------------------------------------------------------------------
145
146	CONTAINS
147
148	SUBROUTINE asm_inc_init
149	!!----------------------------------------------------------------------
150	!! * ROUTINE asm_inc_init *
151	!!
152	!! ** Purpose : Initialize the assimilation increment and IAU weights.
153	!!
154	!! ** Method : Initialize the assimilation increment and IAU weights.
155	!!
156	!! ** Action :
157	!!
158	!! History :
159	!! ! 07-03 (M. Martin) Met Office version
160	!! ! 07-04 (A. Weaver) Merge with OPAVAR/NEMOVAR
161	!!----------------------------------------------------------------------
162
163	IMPLICIT NONE
164
165	!! * Modules used
166	NAMELIST/nam_asminc/ ln_bkgwri, ln_trjwri, &
167	& ln_trainc, ln_dyninc, ln_sshinc, &
168	& ln_asmdin, ln_asmiau, &
169	& nitbkg, nitdin, nitiaustr, nitiaufin, niaufn, &
170	& nittrjfrq, ln_salfix, salfixmin
171
172	!! * Local declarations
173	INTEGER :: jt
174
175	INTEGER :: imid
176	INTEGER :: inum
177	INTEGER :: iiauper ! Number of time steps in the IAU period
178	INTEGER :: icycper ! Number of time steps in the cycle
179	INTEGER :: iitend_date ! Date YYYYMMDD of final time step
180	INTEGER :: iitbkg_date ! Date YYYYMMDD of background time step for Jb term
181	INTEGER :: iitdin_date ! Date YYYYMMDD of background time step for DI
182	INTEGER :: iitiaustr_date ! Date YYYYMMDD of IAU interval start time step
183	INTEGER :: iitiaufin_date ! Date YYYYMMDD of IAU interval final time step
184
185	REAL(wp) :: znorm ! Normalization factor for IAU weights
186	REAL(wp) :: ztotwgt ! Value of time-integrated IAU weights
187	! (should be equal to one)
188	REAL(wp) :: z_inc_dateb ! Start date of interval on which increment is valid
189	REAL(wp) :: z_inc_datef ! End date of interval on which increment is valid
190	REAL(wp) :: zdate_bkg ! Date in background state file for DI
191	REAL(wp) :: zdate_inc ! Time axis in increments file
192
193	!-----------------------------------------------------------------------
194	! Read Namelist nam_asminc : assimilation increment interface
195	!-----------------------------------------------------------------------
196
197	! Set default values
198	ln_bkgwri = .FALSE.
199	ln_trjwri = .FALSE.
200	ln_trainc = .FALSE.
201	ln_dyninc = .FALSE.
202	ln_sshinc = .FALSE.
203	ln_asmdin = .FALSE.
204	ln_asmiau = .TRUE.
205	ln_salfix = .FALSE.
206	salfixmin = -9999
207	nitbkg = 0
208	nitdin = 0
209	nitiaustr = 1
210	nitiaufin = 150 ! = 10 days with ORCA2
211	niaufn = 0
212	nittrjfrq = 1
213
214	REWIND ( numnam )
215	READ ( numnam, nam_asminc )
216
217	! Control print
218	IF(lwp) THEN
219	WRITE(numout,*)
220	WRITE(numout,*) 'asm_inc_init : Assimilation increment initialization :'
221	WRITE(numout,*) '~~~~~~~~~~~~'
222	WRITE(numout,*) ' Namelist namasm : set assimilation increment parameters'
223	WRITE(numout,*) ' Logical switch for writing out background state ', &
224	& ' ln_bkgwri = ', ln_bkgwri
225	WRITE(numout,*) ' Logical switch for writing out state trajectory ', &
226	& ' ln_trjwri = ', ln_trjwri
227	WRITE(numout,*) ' Logical switch for applying tracer increments ', &
228	& ' ln_trainc = ', ln_trainc
229	WRITE(numout,*) ' Logical switch for applying velocity increments ', &
230	& ' ln_dyninc = ', ln_dyninc
231	WRITE(numout,*) ' Logical switch for applying SSH increments ', &
232	& ' ln_sshinc = ', ln_sshinc
233	WRITE(numout,*) ' Logical switch for Direct Initialization (DI) ', &
234	& ' ln_asmdin = ', ln_asmdin
235	WRITE(numout,*) ' Logical switch for Incremental Analysis Updating (IAU) ', &
236	& ' ln_asmiau = ', ln_asmiau
237	WRITE(numout,*) ' Timestep of background in [0,nitend-nit000-1] ', &
238	& ' nitbkg = ', nitbkg
239	WRITE(numout,*) ' Timestep of background for DI in [0,nitend-nit000-1] ', &
240	& ' nitdin = ', nitdin
241	WRITE(numout,*) ' Timestep of start of IAU interval in [0,nitend-nit000-1]', &
242	& ' nitiaustr = ', nitiaustr
243	WRITE(numout,*) ' Timestep of end of IAU interval in [0,nitend-nit000-1] ', &
244	& ' nitiaufin = ', nitiaufin
245	WRITE(numout,*) ' Type of IAU weighting function ', &
246	& ' niaufn = ', niaufn
247	WRITE(numout,*) ' Frequency of trajectory output for 4D-VAR ', &
248	& ' nittrjfrq = ', nittrjfrq
249	WRITE(numout,*) ' Logical switch for ensuring that the sa > salfixmin ', &
250	& ' ln_salfix = ', ln_salfix
251	WRITE(numout,*) ' Minimum salinity after applying the increments ', &
252	& ' salfixmin = ', salfixmin
253	ENDIF
254
255	nitbkg_r = nitbkg + nit000 - 1 ! Background time referenced to nit000
256	nitdin_r = nitdin + nit000 - 1 ! Background time for DI referenced to nit000
257	nitiaustr_r = nitiaustr + nit000 - 1 ! Start of IAU interval referenced to nit000
258	nitiaufin_r = nitiaufin + nit000 - 1 ! End of IAU interval referenced to nit000
259
260	iiauper = nitiaufin_r - nitiaustr_r + 1 ! IAU interval length
261	icycper = nitend - nit000 + 1 ! Cycle interval length
262
263	! Date of final time step
264	CALL calc_date( nit000, nitend, ndate0, iitend_date )
265
266	! Background time for Jb referenced to ndate0
267	CALL calc_date( nit000, nitbkg_r, ndate0, iitbkg_date )
268
269	! Background time for DI referenced to ndate0
270	CALL calc_date( nit000, nitdin_r, ndate0, iitdin_date )
271
272	! IAU start time referenced to ndate0
273	CALL calc_date( nit000, nitiaustr_r, ndate0, iitiaustr_date )
274
275	! IAU end time referenced to ndate0
276	CALL calc_date( nit000, nitiaufin_r, ndate0, iitiaufin_date )
277
278	IF(lwp) THEN
279	WRITE(numout,*)
280	WRITE(numout,*) ' Time steps referenced to current cycle:'
281	WRITE(numout,*) ' iitrst = ', nit000 - 1
282	WRITE(numout,*) ' nit000 = ', nit000
283	WRITE(numout,*) ' nitend = ', nitend
284	WRITE(numout,*) ' nitbkg_r = ', nitbkg_r
285	WRITE(numout,*) ' nitdin_r = ', nitdin_r
286	WRITE(numout,*) ' nitiaustr_r = ', nitiaustr_r
287	WRITE(numout,*) ' nitiaufin_r = ', nitiaufin_r
288	WRITE(numout,*) ' nittrjfrq = ', nittrjfrq
289	WRITE(numout,*)
290	WRITE(numout,*) ' Dates referenced to current cycle:'
291	WRITE(numout,*) ' ndastp = ', ndastp
292	WRITE(numout,*) ' ndate0 = ', ndate0
293	WRITE(numout,*) ' iitend_date = ', iitend_date
294	WRITE(numout,*) ' iitbkg_date = ', iitbkg_date
295	WRITE(numout,*) ' iitdin_date = ', iitdin_date
296	WRITE(numout,*) ' iitiaustr_date = ', iitiaustr_date
297	WRITE(numout,*) ' iitiaufin_date = ', iitiaufin_date
298	ENDIF
299
300	IF ( nacc /= 0 ) &
301	& CALL ctl_stop( ' nacc /= 0 and key_asminc :', &
302	& ' Assimilation increments have only been implemented', &
303	& ' for synchronous time stepping' )
304
305	IF ( ( ln_asmdin ).AND.( ln_asmiau ) ) &
306	& CALL ctl_stop( ' ln_asmdin and ln_asmiau :', &
307	& ' Choose Direct Initialization OR Incremental Analysis Updating')
308
309	IF ( ( ( .NOT. ln_asmdin ).AND.( .NOT. ln_asmiau ) ) &
310	.AND.( ( ln_trainc ).OR.( ln_dyninc ).OR.( ln_sshinc ) ) ) &
311	& CALL ctl_stop( ' One or more of ln_trainc, ln_dyninc and ln_sshinc is set to .true.', &
312	& ' but ln_asmdin and ln_asmiau are both set to .false. :', &
313	& ' Inconsistent options')
314
315	IF ( ( ln_bkgwri ).AND.( ( ln_asmdin ).OR.( ln_asmiau ) ) ) &
316	& CALL ctl_stop( ' ln_bkgwri and either ln_asmdin or ln_asmiau are set to .true.:', &
317	& ' The background state must be written before applying the increments')
318
319	IF ( ( niaufn /= 0 ).AND.( niaufn /= 1 ) ) &
320	& CALL ctl_stop( ' niaufn /= 0 or niaufn /=1 :', &
321	& ' Type IAU weighting function is invalid')
322
323	IF ( ( .NOT. ln_trainc ).AND.( .NOT. ln_dyninc ).AND.( .NOT. ln_sshinc ) &
324	& ) &
325	& CALL ctl_warn( ' ln_trainc, ln_dyninc and ln_sshinc are set to .false. :', &
326	& ' The assimilation increments are not applied')
327
328	IF ( ( ln_asmiau ).AND.( nitiaustr == nitiaufin ) ) &
329	& CALL ctl_stop( ' nitiaustr = nitiaufin :', &
330	& ' IAU interval is of zero length')
331
332	IF ( ( ln_asmiau ).AND.( ( nitiaustr_r < nit000 ).OR.( nitiaufin_r > nitend ) ) ) &
333	& CALL ctl_stop( ' nitiaustr or nitiaufin :', &
334	& ' IAU starting or final time step is outside the cycle interval', &
335	& ' Valid range nit000 to nitend')
336
337	IF ( ( nitbkg_r < nit000 - 1 ).OR.( nitbkg_r > nitend ) ) &
338	& CALL ctl_stop( ' nitbkg :', &
339	& ' Background time step is outside the cycle interval')
340
341	IF ( ( nitdin_r < nit000 - 1 ).OR.( nitdin_r > nitend ) ) &
342	& CALL ctl_stop( ' nitdin :', &
343	& ' Background time step for Direct Initialization is outside', &
344	& ' the cycle interval')
345
346	IF ( nstop > 0 ) RETURN ! if there are any errors then go no further
347
348	!--------------------------------------------------------------------
349	! Initialize the Incremental Analysis Updating weighting function
350	!--------------------------------------------------------------------
351
352	IF ( ln_asmiau ) THEN
353
354	ALLOCATE( wgtiau( icycper ) )
355
356	wgtiau(:) = 0.0
357
358	IF ( niaufn == 0 ) THEN
359
360	!---------------------------------------------------------
361	! Constant IAU forcing
362	!---------------------------------------------------------
363
364	DO jt = 1, iiauper
365	wgtiau(jt+nitiaustr-1) = 1.0 / REAL( iiauper )
366	END DO
367
368	ELSEIF ( niaufn == 1 ) THEN
369
370	!---------------------------------------------------------
371	! Linear hat-like, centred in middle of IAU interval
372	!---------------------------------------------------------
373
374	! Compute the normalization factor
375	znorm = 0.0
376	IF ( MOD( iiauper, 2 ) == 0 ) THEN ! Even number of time steps in IAU interval
377	imid = iiauper / 2
378	DO jt = 1, imid
379	znorm = znorm + REAL( jt )
380	END DO
381	znorm = 2.0 * znorm
382	ELSE ! Odd number of time steps in IAU interval
383	imid = ( iiauper + 1 ) / 2
384	DO jt = 1, imid - 1
385	znorm = znorm + REAL( jt )
386	END DO
387	znorm = 2.0 * znorm + REAL( imid )
388	ENDIF
389	znorm = 1.0 / znorm
390
391	DO jt = 1, imid - 1
392	wgtiau(jt+nitiaustr-1) = REAL( jt ) * znorm
393	END DO
394	DO jt = imid, iiauper
395	wgtiau(jt+nitiaustr-1) = REAL( iiauper - jt + 1 ) * znorm
396	END DO
397
398	ENDIF
399
400	! Test that the integral of the weights over the weighting interval equals 1
401	IF(lwp) THEN
402	WRITE(numout,*)
403	WRITE(numout,*) 'asm_inc_init : IAU weights'
404	WRITE(numout,*) '~~~~~~~~~~~~'
405	WRITE(numout,*) ' time step IAU weight'
406	WRITE(numout,*) ' ========= ====================='
407	ztotwgt = 0.0
408	DO jt = 1, icycper
409	ztotwgt = ztotwgt + wgtiau(jt)
410	WRITE(numout,*) ' ', jt, ' ', wgtiau(jt)
411	END DO
412	WRITE(numout,*) ' ==================================='
413	WRITE(numout,*) ' Time-integrated weight = ', ztotwgt
414	WRITE(numout,*) ' ==================================='
415	ENDIF
416
417	ENDIF
418
419	!--------------------------------------------------------------------
420	! Allocate and initialize the increment arrays
421	!--------------------------------------------------------------------
422
423	ALLOCATE( t_bkginc(jpi,jpj,jpk) )
424	ALLOCATE( s_bkginc(jpi,jpj,jpk) )
425	ALLOCATE( u_bkginc(jpi,jpj,jpk) )
426	ALLOCATE( v_bkginc(jpi,jpj,jpk) )
427	ALLOCATE( ssh_bkginc(jpi,jpj) )
428	#if defined key_asminc
429	ALLOCATE( ssh_iau(jpi,jpj) )
430	#endif
431	t_bkginc(:,:,:) = 0.0
432	s_bkginc(:,:,:) = 0.0
433	u_bkginc(:,:,:) = 0.0
434	v_bkginc(:,:,:) = 0.0
435	ssh_bkginc(:,:) = 0.0
436	#if defined key_asminc
437	ssh_iau(:,:) = 0.0
438	#endif
439	IF ( ( ln_trainc ).OR.( ln_dyninc ).OR.( ln_sshinc ) ) THEN
440
441	!--------------------------------------------------------------------
442	! Read the increments from file
443	!--------------------------------------------------------------------
444
445	CALL iom_open( c_asminc, inum )
446
447	CALL iom_get( inum, 'time', zdate_inc )
448
449	CALL iom_get( inum, 'z_inc_dateb', z_inc_dateb )
450	CALL iom_get( inum, 'z_inc_datef', z_inc_datef )
451	z_inc_dateb = zdate_inc
452	z_inc_datef = zdate_inc
453
454	IF(lwp) THEN
455	WRITE(numout,*)
456	WRITE(numout,*) 'asm_inc_init : Assimilation increments valid ', &
457	& ' between dates ', NINT( z_inc_dateb ),' and ', &
458	& NINT( z_inc_datef )
459	WRITE(numout,*) '~~~~~~~~~~~~'
460	ENDIF
461
462	IF ( ( NINT( z_inc_dateb ) < ndastp ) &
463	& .OR.( NINT( z_inc_datef ) > iitend_date ) ) &
464	& CALL ctl_warn( ' Validity time of assimilation increments is ', &
465	& ' outside the assimilation interval' )
466
467	IF ( ( ln_asmdin ).AND.( NINT( zdate_inc ) /= iitdin_date ) ) &
468	& CALL ctl_warn( ' Validity time of assimilation increments does ', &
469	& ' not agree with Direct Initialization time' )
470
471	IF ( ln_trainc ) THEN
472	CALL iom_get( inum, jpdom_autoglo, 'bckint', t_bkginc, 1 )
473	CALL iom_get( inum, jpdom_autoglo, 'bckins', s_bkginc, 1 )
474	! Apply the masks
475	t_bkginc(:,:,:) = t_bkginc(:,:,:) * tmask(:,:,:)
476	s_bkginc(:,:,:) = s_bkginc(:,:,:) * tmask(:,:,:)
477	! Set missing increments to 0.0 rather than 1e+20
478	! to allow for differences in masks
479	WHERE( ABS( t_bkginc(:,:,:) ) > 1.0e+10 ) t_bkginc(:,:,:) = 0.0
480	WHERE( ABS( s_bkginc(:,:,:) ) > 1.0e+10 ) s_bkginc(:,:,:) = 0.0
481	ENDIF
482
483	IF ( ln_dyninc ) THEN
484	CALL iom_get( inum, jpdom_autoglo, 'bckinu', u_bkginc, 1 )
485	CALL iom_get( inum, jpdom_autoglo, 'bckinv', v_bkginc, 1 )
486	! Apply the masks
487	u_bkginc(:,:,:) = u_bkginc(:,:,:) * umask(:,:,:)
488	v_bkginc(:,:,:) = v_bkginc(:,:,:) * vmask(:,:,:)
489	! Set missing increments to 0.0 rather than 1e+20
490	! to allow for differences in masks
491	WHERE( ABS( u_bkginc(:,:,:) ) > 1.0e+10 ) u_bkginc(:,:,:) = 0.0
492	WHERE( ABS( v_bkginc(:,:,:) ) > 1.0e+10 ) v_bkginc(:,:,:) = 0.0
493	ENDIF
494
495	IF ( ln_sshinc ) THEN
496	CALL iom_get( inum, jpdom_autoglo, 'bckineta', ssh_bkginc, 1 )
497	! Apply the masks
498	ssh_bkginc(:,:) = ssh_bkginc(:,:) * tmask(:,:,1)
499	! Set missing increments to 0.0 rather than 1e+20
500	! to allow for differences in masks
501	WHERE( ABS( ssh_bkginc(:,:) ) > 1.0e+10 ) ssh_bkginc(:,:) = 0.0
502	ENDIF
503
504	CALL iom_close( inum )
505
506	ENDIF
507
508	!-----------------------------------------------------------------------
509	! Allocate and initialize the background state arrays
510	!-----------------------------------------------------------------------
511
512	IF ( ln_asmdin ) THEN
513
514	ALLOCATE( t_bkg(jpi,jpj,jpk) )
515	ALLOCATE( s_bkg(jpi,jpj,jpk) )
516	ALLOCATE( u_bkg(jpi,jpj,jpk) )
517	ALLOCATE( v_bkg(jpi,jpj,jpk) )
518	ALLOCATE( ssh_bkg(jpi,jpj) )
519
520	t_bkg(:,:,:) = 0.0
521	s_bkg(:,:,:) = 0.0
522	u_bkg(:,:,:) = 0.0
523	v_bkg(:,:,:) = 0.0
524	ssh_bkg(:,:) = 0.0
525
526	!--------------------------------------------------------------------
527	! Read from file the background state at analysis time
528	!--------------------------------------------------------------------
529
530	CALL iom_open( c_asmdin, inum )
531
532	CALL iom_get( inum, 'zdate', zdate_bkg )
533
534	IF(lwp) THEN
535	WRITE(numout,*)
536	WRITE(numout,*) 'asm_inc_init : Assimilation background state valid at : ', &
537	& NINT( zdate_bkg )
538	WRITE(numout,*) '~~~~~~~~~~~~'
539	ENDIF
540
541	IF ( NINT( zdate_bkg ) /= iitdin_date ) &
542	& CALL ctl_warn( ' Validity time of assimilation background state does', &
543	& ' not agree with Direct Initialization time' )
544
545	IF ( ln_trainc ) THEN
546	CALL iom_get( inum, jpdom_autoglo, 'tn', t_bkg )
547	CALL iom_get( inum, jpdom_autoglo, 'sn', s_bkg )
548	t_bkg(:,:,:) = t_bkg(:,:,:) * tmask(:,:,:)
549	s_bkg(:,:,:) = s_bkg(:,:,:) * tmask(:,:,:)
550	ENDIF
551
552	IF ( ln_dyninc ) THEN
553	CALL iom_get( inum, jpdom_autoglo, 'un', u_bkg )
554	CALL iom_get( inum, jpdom_autoglo, 'vn', v_bkg )
555	u_bkg(:,:,:) = u_bkg(:,:,:) * umask(:,:,:)
556	v_bkg(:,:,:) = v_bkg(:,:,:) * vmask(:,:,:)
557	ENDIF
558
559	IF ( ln_sshinc ) THEN
560	CALL iom_get( inum, jpdom_autoglo, 'sshn', ssh_bkg )
561	ssh_bkg(:,:) = ssh_bkg(:,:) * tmask(:,:,1)
562	ENDIF
563
564	CALL iom_close( inum )
565
566	ENDIF
567
568	END SUBROUTINE asm_inc_init
569
570	SUBROUTINE calc_date( kit000, kt, kdate0, kdate )
571	!!----------------------------------------------------------------------
572	!! * ROUTINE calc_date *
573	!!
574	!! ** Purpose : Compute the calendar date YYYYMMDD at a given time step.
575	!!
576	!! ** Method : Compute the calendar date YYYYMMDD at a given time step.
577	!!
578	!! ** Action :
579	!!
580	!! History :
581	!! ! 07-04 (A. Weaver)
582	!! ! 10-05 (D. Lea) Update to work with NEMO vn3.2
583	!!----------------------------------------------------------------------
584
585	IMPLICIT NONE
586
587	!! * Arguments
588
589	INTEGER, INTENT(IN) :: kit000 ! Initial time step
590	INTEGER, INTENT(IN) :: kt ! Current time step referenced to kit000
591	INTEGER, INTENT(IN) :: kdate0 ! Initial date
592	INTEGER, INTENT(OUT) :: kdate ! Current date reference to kdate0
593
594	!! * Local declarations
595
596	INTEGER :: iyea0 ! Initial year
597	INTEGER :: imon0 ! Initial month
598	INTEGER :: iday0 ! Initial day
599	INTEGER :: iyea ! Current year
600	INTEGER :: imon ! Current month
601	INTEGER :: iday ! Current day
602	INTEGER :: idaystp ! Number of days between initial and current date
603	INTEGER :: idaycnt ! Day counter
604
605	INTEGER, DIMENSION(12) :: imonth_len !: length in days of the months of the current year
606
607	!-----------------------------------------------------------------------
608	! Compute the calendar date YYYYMMDD
609	!-----------------------------------------------------------------------
610
611	! Initial date
612	iyea0 = kdate0 / 10000
613	imon0 = ( kdate0 - ( iyea0 * 10000 ) ) / 100
614	iday0 = kdate0 - ( iyea0 * 10000 ) - ( imon0 * 100 )
615
616	! Check that kt >= kit000 - 1
617	IF ( kt < kit000 - 1 ) CALL ctl_stop( ' kt must be >= kit000 - 1')
618
619	! If kt = kit000 - 1 then set the date to the restart date
620	IF ( kt == kit000 - 1 ) THEN
621
622	kdate = ndastp
623	RETURN
624
625	ENDIF
626
627	! Compute the number of days from the initial date
628	idaystp = INT( REAL( kt - kit000 ) * rdt / 86400. )
629
630	iday = iday0
631	imon = imon0
632	iyea = iyea0
633	idaycnt = 0
634
635	CALL calc_month_len( iyea, imonth_len )
636
637	DO WHILE ( idaycnt < idaystp )
638	iday = iday + 1
639	IF ( iday > imonth_len(imon) ) THEN
640	iday = 1
641	imon = imon + 1
642	ENDIF
643	IF ( imon > 12 ) THEN
644	imon = 1
645	iyea = iyea + 1
646	CALL calc_month_len( iyea, imonth_len ) ! update month lengths
647	ENDIF
648	idaycnt = idaycnt + 1
649	END DO
650
651	kdate = iyea * 10000 + imon * 100 + iday
652
653	END SUBROUTINE
654
655	SUBROUTINE calc_month_len( iyear, imonth_len )
656	!!----------------------------------------------------------------------
657	!! * ROUTINE calc_month_len *
658	!!
659	!! ** Purpose : Compute the number of days in a months given a year.
660	!!
661	!! ** Method :
662	!!
663	!! ** Action :
664	!!
665	!! History :
666	!! ! 10-05 (D. Lea) New routine based on day_init
667	!!----------------------------------------------------------------------
668
669	INTEGER, DIMENSION(12) :: imonth_len !: length in days of the months of the current year
670	INTEGER :: iyear !: year
671
672	! length of the month of the current year (from nleapy, read in namelist)
673	IF ( nleapy < 2 ) THEN
674	imonth_len(:) = (/ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 /)
675	IF ( nleapy == 1 ) THEN ! we are using calendar with leap years
676	IF ( MOD(iyear, 4) == 0 .AND. ( MOD(iyear, 400) == 0 .OR. MOD(iyear, 100) /= 0 ) ) THEN
677	imonth_len(2) = 29
678	ENDIF
679	ENDIF
680	ELSE
681	imonth_len(:) = nleapy ! all months with nleapy days per year
682	ENDIF
683
684	END SUBROUTINE
685
686	SUBROUTINE tra_asm_inc( kt )
687	!!----------------------------------------------------------------------
688	!! * ROUTINE tra_asm_inc *
689	!!
690	!! ** Purpose : Apply the tracer (T and S) assimilation increments
691	!!
692	!! ** Method : Direct initialization or Incremental Analysis Updating
693	!!
694	!! ** Action :
695	!!
696	!! History :
697	!! ! 07-03 (M. Martin) Met Office version
698	!! ! 07-04 (A. Weaver) Merge with OPAVAR/NEMOVAR
699	!!----------------------------------------------------------------------
700
701	IMPLICIT NONE
702
703	!! * Arguments
704	INTEGER, INTENT(IN) :: kt ! Current time step
705
706	!! * Local declarations
707	INTEGER :: ji,jj,jk
708	INTEGER :: it
709	REAL(wp) :: zincwgt ! IAU weight for current time step
710
711	IF ( ln_asmiau ) THEN
712
713	!--------------------------------------------------------------------
714	! Incremental Analysis Updating
715	!--------------------------------------------------------------------
716
717	IF ( ( kt >= nitiaustr_r ).AND.( kt <= nitiaufin_r ) ) THEN
718
719	it = kt - nit000 + 1
720	zincwgt = wgtiau(it) / rdt ! IAU weight for the current time step
721
722	IF(lwp) THEN
723	WRITE(numout,*)
724	WRITE(numout,*) 'tra_asm_inc : Tracer IAU at time step = ', &
725	& kt,' with IAU weight = ', wgtiau(it)
726	WRITE(numout,*) '~~~~~~~~~~~~'
727	ENDIF
728
729	! Update the tracer tendencies
730	DO jk = 1, jpkm1
731	tsa(:,:,jk,jp_tem) = tsa(:,:,jk,jp_tem) + t_bkginc(:,:,jk) * zincwgt
732	tsa(:,:,jk,jp_sal) = tsa(:,:,jk,jp_sal) + s_bkginc(:,:,jk) * zincwgt
733	END DO
734
735	! Salinity fix
736	IF (ln_salfix) THEN
737	DO jk = 1, jpkm1
738	DO jj = 1, jpj
739	DO ji= 1, jpi
740	tsa(ji,jj,jk,jp_sal) = MAX( tsa(ji,jj,jk,jp_sal), salfixmin )
741	END DO
742	END DO
743	END DO
744	ENDIF
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	tsn(:,:,:,jp_tem) = t_bkg(:,:,:) + t_bkginc(:,:,:)
766	tsn(:,:,:,jp_sal) = s_bkg(:,:,:) + s_bkginc(:,:,:)
767
768	! Optional salinity fix
769	IF (ln_salfix) THEN
770	DO jk = 1, jpkm1
771	DO jj = 1, jpj
772	DO ji= 1, jpi
773	tsn(ji,jj,jk,jp_sal) = MAX( tsn(ji,jj,jk,jp_sal), salfixmin )
774	END DO
775	END DO
776	END DO
777	ENDIF
778
779	tsb(:,:,:,:) = tsn(:,:,:,:) ! Update before fields
780
781	CALL eos( tsb, rhd, rhop ) ! Before potential and in situ densities
782
783	#if ! defined key_c1d
784	IF( ln_zps ) &
785	& CALL zps_hde( nit000, jpts, tsb, & ! Partial steps: before horizontal derivative
786	& gtsu, gtsv, rhd, & ! of T, S, rd at the bottom ocean level
787	& gru , grv )
788	#endif
789
790	DEALLOCATE( t_bkginc )
791	DEALLOCATE( s_bkginc )
792	DEALLOCATE( t_bkg )
793	DEALLOCATE( s_bkg )
794	ENDIF
795
796	ENDIF
797
798	END SUBROUTINE tra_asm_inc
799
800	SUBROUTINE dyn_asm_inc( kt )
801	!!----------------------------------------------------------------------
802	!! * ROUTINE dyn_asm_inc *
803	!!
804	!! ** Purpose : Apply the dynamics (u and v) assimilation increments.
805	!!
806	!! ** Method : Direct initialization or Incremental Analysis Updating.
807	!!
808	!! ** Action :
809	!!
810	!! History :
811	!! ! 07-03 (M. Martin) Met Office version
812	!! ! 07-04 (A. Weaver) Merge with OPAVAR/NEMOVAR
813	!!----------------------------------------------------------------------
814
815	IMPLICIT NONE
816
817	!! * Arguments
818	INTEGER, INTENT(IN) :: kt ! Current time step
819
820	!! * Local declarations
821	INTEGER :: jk
822	INTEGER :: it
823	REAL(wp) :: zincwgt ! IAU weight for current time step
824
825	IF ( ln_asmiau ) THEN
826
827	!--------------------------------------------------------------------
828	! Incremental Analysis Updating
829	!--------------------------------------------------------------------
830
831	IF ( ( kt >= nitiaustr_r ).AND.( kt <= nitiaufin_r ) ) THEN
832
833	it = kt - nit000 + 1
834	zincwgt = wgtiau(it) / rdt ! IAU weight for the current time step
835
836	IF(lwp) THEN
837	WRITE(numout,*)
838	WRITE(numout,*) 'dyn_asm_inc : Dynamics IAU at time step = ', &
839	& kt,' with IAU weight = ', wgtiau(it)
840	WRITE(numout,*) '~~~~~~~~~~~~'
841	ENDIF
842
843	! Update the dynamic tendencies
844	DO jk = 1, jpkm1
845	ua(:,:,jk) = ua(:,:,jk) + u_bkginc(:,:,jk) * zincwgt
846	va(:,:,jk) = va(:,:,jk) + v_bkginc(:,:,jk) * zincwgt
847	END DO
848
849	IF ( kt == nitiaufin_r ) THEN
850	DEALLOCATE( u_bkginc )
851	DEALLOCATE( v_bkginc )
852	ENDIF
853
854	ENDIF
855
856	ELSEIF ( ln_asmdin ) THEN
857
858	!--------------------------------------------------------------------
859	! Direct Initialization
860	!--------------------------------------------------------------------
861
862	IF ( kt == nitdin_r ) THEN
863
864	neuler = 0 ! Force Euler forward step
865
866	! Initialize the now fields with the background + increment
867	un(:,:,:) = u_bkg(:,:,:) + u_bkginc(:,:,:)
868	vn(:,:,:) = v_bkg(:,:,:) + v_bkginc(:,:,:)
869
870	ub(:,:,:) = un(:,:,:) ! Update before fields
871	vb(:,:,:) = vn(:,:,:)
872
873	CALL div_cur( kt ) ! Compute divergence and curl for now fields
874	IF( n_cla == 1 ) CALL div_cla( kt ) ! Cross Land Advection (Update Hor. divergence)
875
876	rotb (:,:,:) = rotn (:,:,:) ! Update before fields
877	hdivb(:,:,:) = hdivn(:,:,:)
878
879	DEALLOCATE( u_bkg )
880	DEALLOCATE( v_bkg )
881	DEALLOCATE( u_bkginc )
882	DEALLOCATE( v_bkginc )
883
884	ENDIF
885
886	ENDIF
887
888	END SUBROUTINE dyn_asm_inc
889
890	SUBROUTINE ssh_asm_inc( kt )
891	!!----------------------------------------------------------------------
892	!! * ROUTINE ssh_asm_inc *
893	!!
894	!! ** Purpose : Apply the sea surface height assimilation increment.
895	!!
896	!! ** Method : Direct initialization or Incremental Analysis Updating.
897	!!
898	!! ** Action :
899	!!
900	!! History :
901	!! ! 07-03 (M. Martin) Met Office version
902	!! ! 07-04 (A. Weaver) Merge with OPAVAR/NEMOVAR
903	!!----------------------------------------------------------------------
904
905	IMPLICIT NONE
906
907	!! * Arguments
908	INTEGER, INTENT(IN) :: kt ! Current time step
909
910	!! * Local declarations
911	INTEGER :: it
912	REAL(wp) :: zincwgt ! IAU weight for current time step
913
914	IF ( ln_asmiau ) THEN
915
916	!--------------------------------------------------------------------
917	! Incremental Analysis Updating
918	!--------------------------------------------------------------------
919
920	IF ( ( kt >= nitiaustr_r ).AND.( kt <= nitiaufin_r ) ) THEN
921
922	it = kt - nit000 + 1
923	zincwgt = wgtiau(it) / rdt ! IAU weight for the current time step
924
925	IF(lwp) THEN
926	WRITE(numout,*)
927	WRITE(numout,*) 'ssh_asm_inc : SSH IAU at time step = ', &
928	& kt,' with IAU weight = ', wgtiau(it)
929	WRITE(numout,*) '~~~~~~~~~~~~'
930	ENDIF
931
932	! Save the tendency associated with the IAU weighted SSH increment
933	! (applied in dynspg.*)
934	#if defined key_asminc
935	ssh_iau(:,:) = ssh_bkginc(:,:) * zincwgt
936	#endif
937	IF ( kt == nitiaufin_r ) THEN
938	DEALLOCATE( ssh_bkginc )
939	ENDIF
940
941	ENDIF
942
943	ELSEIF ( ln_asmdin ) THEN
944
945	!--------------------------------------------------------------------
946	! Direct Initialization
947	!--------------------------------------------------------------------
948
949	IF ( kt == nitdin_r ) THEN
950
951	neuler = 0 ! Force Euler forward step
952
953	! Initialize the now fields the background + increment
954	sshn(:,:) = ssh_bkg(:,:) + ssh_bkginc(:,:)
955
956	sshb(:,:) = sshn(:,:) ! Update before fields
957
958	DEALLOCATE( ssh_bkg )
959	DEALLOCATE( ssh_bkginc )
960
961	ENDIF
962
963	ENDIF
964
965	END SUBROUTINE ssh_asm_inc
966
967	END MODULE asminc

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