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asminc.F90 in NEMO/branches/2019/dev_r10721_KERNEL-02_Storkey_Coward_IMMERSE_first_steps/src/OCE/ASM – NEMO

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source: NEMO/branches/2019/dev_r10721_KERNEL-02_Storkey_Coward_IMMERSE_first_steps/src/OCE/ASM/asminc.F90 @ 10954

Last change on this file since 10954 was 10954, checked in by acc, 5 years ago
2019/dev_r10721_KERNEL-02_Storkey_Coward_IMMERSE_first_steps : Convert TRA modules and all knock on effects of these conversions. SETTE tested
Property svn:keywords set to `Id`
File size: 47.9 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	!! ! 2014-09 (D. Lea) Local calc_date removed use routine from OBS
14	!! ! 2015-11 (D. Lea) Handle non-zero initial time of day
15	!!----------------------------------------------------------------------
16
17	!!----------------------------------------------------------------------
18	!! asm_inc_init : Initialize the increment arrays and IAU weights
19	!! tra_asm_inc : Apply the tracer (T and S) increments
20	!! dyn_asm_inc : Apply the dynamic (u and v) increments
21	!! ssh_asm_inc : Apply the SSH increment
22	!! ssh_asm_div : Apply divergence associated with SSH increment
23	!! seaice_asm_inc : Apply the seaice increment
24	!!----------------------------------------------------------------------
25	USE oce ! Dynamics and active tracers defined in memory
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 ldfdyn ! lateral diffusion: eddy viscosity coefficients
30	USE eosbn2 ! Equation of state - in situ and potential density
31	USE zpshde ! Partial step : Horizontal Derivative
32	USE asmpar ! Parameters for the assmilation interface
33	USE asmbkg !
34	USE c1d ! 1D initialization
35	USE sbc_oce ! Surface boundary condition variables.
36	USE diaobs , ONLY : calc_date ! Compute the calendar date on a given step
37	#if defined key_si3
38	USE ice , ONLY : hm_i, at_i, at_i_b
39	#endif
40	!
41	USE in_out_manager ! I/O manager
42	USE iom ! Library to read input files
43	USE lib_mpp ! MPP library
44
45	IMPLICIT NONE
46	PRIVATE
47
48	PUBLIC asm_inc_init !: Initialize the increment arrays and IAU weights
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 ssh_asm_div !: Apply the SSH divergence
53	PUBLIC seaice_asm_inc !: Apply the seaice increment
54
55	#if defined key_asminc
56	LOGICAL, PUBLIC, PARAMETER :: lk_asminc = .TRUE. !: Logical switch for assimilation increment interface
57	#else
58	LOGICAL, PUBLIC, PARAMETER :: lk_asminc = .FALSE. !: No assimilation increments
59	#endif
60	LOGICAL, PUBLIC :: ln_bkgwri !: No output of the background state fields
61	LOGICAL, PUBLIC :: ln_asmiau !: No applying forcing with an assimilation increment
62	LOGICAL, PUBLIC :: ln_asmdin !: No direct initialization
63	LOGICAL, PUBLIC :: ln_trainc !: No tracer (T and S) assimilation increments
64	LOGICAL, PUBLIC :: ln_dyninc !: No dynamics (u and v) assimilation increments
65	LOGICAL, PUBLIC :: ln_sshinc !: No sea surface height assimilation increment
66	LOGICAL, PUBLIC :: ln_seaiceinc !: No sea ice concentration increment
67	LOGICAL, PUBLIC :: ln_salfix !: Apply minimum salinity check
68	LOGICAL, PUBLIC :: ln_temnofreeze = .FALSE. !: Don't allow the temperature to drop below freezing
69	INTEGER, PUBLIC :: nn_divdmp !: Apply divergence damping filter nn_divdmp times
70
71	REAL(wp), PUBLIC, DIMENSION(:,:,:), ALLOCATABLE :: t_bkg , s_bkg !: Background temperature and salinity
72	REAL(wp), PUBLIC, DIMENSION(:,:,:), ALLOCATABLE :: u_bkg , v_bkg !: Background u- & v- velocity components
73	REAL(wp), PUBLIC, DIMENSION(:,:,:), ALLOCATABLE :: t_bkginc, s_bkginc !: Increment to the background T & S
74	REAL(wp), PUBLIC, DIMENSION(:,:,:), ALLOCATABLE :: u_bkginc, v_bkginc !: Increment to the u- & v-components
75	REAL(wp), PUBLIC, DIMENSION(:) , ALLOCATABLE :: wgtiau !: IAU weights for each time step
76	#if defined key_asminc
77	REAL(wp), PUBLIC, DIMENSION(:,:) , ALLOCATABLE :: ssh_iau !: IAU-weighted sea surface height increment
78	#endif
79	! !!! time steps relative to the cycle interval [0,nitend-nit000-1]
80	INTEGER , PUBLIC :: nitbkg !: Time step of the background state used in the Jb term
81	INTEGER , PUBLIC :: nitdin !: Time step of the background state for direct initialization
82	INTEGER , PUBLIC :: nitiaustr !: Time step of the start of the IAU interval
83	INTEGER , PUBLIC :: nitiaufin !: Time step of the end of the IAU interval
84	!
85	INTEGER , PUBLIC :: niaufn !: Type of IAU weighing function: = 0 Constant weighting
86	! !: = 1 Linear hat-like, centred in middle of IAU interval
87	REAL(wp), PUBLIC :: salfixmin !: Ensure that the salinity is larger than this value if (ln_salfix)
88
89	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: ssh_bkg, ssh_bkginc ! Background sea surface height and its increment
90	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: seaice_bkginc ! Increment to the background sea ice conc
91	#if defined key_cice && defined key_asminc
92	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: ndaice_da ! ice increment tendency into CICE
93	#endif
94
95	!! * Substitutions
96	# include "vectopt_loop_substitute.h90"
97	!!----------------------------------------------------------------------
98	!! NEMO/OCE 4.0 , NEMO Consortium (2018)
99	!! $Id$
100	!! Software governed by the CeCILL license (see ./LICENSE)
101	!!----------------------------------------------------------------------
102	CONTAINS
103
104	SUBROUTINE asm_inc_init( Kmm )
105	!!----------------------------------------------------------------------
106	!! * ROUTINE asm_inc_init *
107	!!
108	!! ** Purpose : Initialize the assimilation increment and IAU weights.
109	!!
110	!! ** Method : Initialize the assimilation increment and IAU weights.
111	!!
112	!! ** Action :
113	!!----------------------------------------------------------------------
114	INTEGER, INTENT(in) :: Kmm ! time level index
115	INTEGER :: ji, jj, jk, jt ! dummy loop indices
116	INTEGER :: imid, inum ! local integers
117	INTEGER :: ios ! Local integer output status for namelist read
118	INTEGER :: iiauper ! Number of time steps in the IAU period
119	INTEGER :: icycper ! Number of time steps in the cycle
120	REAL(KIND=dp) :: ditend_date ! Date YYYYMMDD.HHMMSS of final time step
121	REAL(KIND=dp) :: ditbkg_date ! Date YYYYMMDD.HHMMSS of background time step for Jb term
122	REAL(KIND=dp) :: ditdin_date ! Date YYYYMMDD.HHMMSS of background time step for DI
123	REAL(KIND=dp) :: ditiaustr_date ! Date YYYYMMDD.HHMMSS of IAU interval start time step
124	REAL(KIND=dp) :: ditiaufin_date ! Date YYYYMMDD.HHMMSS of IAU interval final time step
125
126	REAL(wp) :: znorm ! Normalization factor for IAU weights
127	REAL(wp) :: ztotwgt ! Value of time-integrated IAU weights (should be equal to one)
128	REAL(wp) :: z_inc_dateb ! Start date of interval on which increment is valid
129	REAL(wp) :: z_inc_datef ! End date of interval on which increment is valid
130	REAL(wp) :: zdate_bkg ! Date in background state file for DI
131	REAL(wp) :: zdate_inc ! Time axis in increments file
132	!
133	REAL(wp), ALLOCATABLE, DIMENSION(:,:) :: zhdiv ! 2D workspace
134	!!
135	NAMELIST/nam_asminc/ ln_bkgwri, &
136	& ln_trainc, ln_dyninc, ln_sshinc, &
137	& ln_asmdin, ln_asmiau, &
138	& nitbkg, nitdin, nitiaustr, nitiaufin, niaufn, &
139	& ln_salfix, salfixmin, nn_divdmp
140	!!----------------------------------------------------------------------
141
142	!-----------------------------------------------------------------------
143	! Read Namelist nam_asminc : assimilation increment interface
144	!-----------------------------------------------------------------------
145	ln_seaiceinc = .FALSE.
146	ln_temnofreeze = .FALSE.
147
148	REWIND( numnam_ref ) ! Namelist nam_asminc in reference namelist : Assimilation increment
149	READ ( numnam_ref, nam_asminc, IOSTAT = ios, ERR = 901)
150	901 IF( ios /= 0 ) CALL ctl_nam ( ios , 'nam_asminc in reference namelist', lwp )
151	REWIND( numnam_cfg ) ! Namelist nam_asminc in configuration namelist : Assimilation increment
152	READ ( numnam_cfg, nam_asminc, IOSTAT = ios, ERR = 902 )
153	902 IF( ios > 0 ) CALL ctl_nam ( ios , 'nam_asminc in configuration namelist', lwp )
154	IF(lwm) WRITE ( numond, nam_asminc )
155
156	! Control print
157	IF(lwp) THEN
158	WRITE(numout,*)
159	WRITE(numout,*) 'asm_inc_init : Assimilation increment initialization :'
160	WRITE(numout,*) '~~~~~~~~~~~~'
161	WRITE(numout,*) ' Namelist namasm : set assimilation increment parameters'
162	WRITE(numout,*) ' Logical switch for writing out background state ln_bkgwri = ', ln_bkgwri
163	WRITE(numout,*) ' Logical switch for applying tracer increments ln_trainc = ', ln_trainc
164	WRITE(numout,*) ' Logical switch for applying velocity increments ln_dyninc = ', ln_dyninc
165	WRITE(numout,*) ' Logical switch for applying SSH increments ln_sshinc = ', ln_sshinc
166	WRITE(numout,*) ' Logical switch for Direct Initialization (DI) ln_asmdin = ', ln_asmdin
167	WRITE(numout,*) ' Logical switch for applying sea ice increments ln_seaiceinc = ', ln_seaiceinc
168	WRITE(numout,*) ' Logical switch for Incremental Analysis Updating (IAU) ln_asmiau = ', ln_asmiau
169	WRITE(numout,*) ' Timestep of background in [0,nitend-nit000-1] nitbkg = ', nitbkg
170	WRITE(numout,*) ' Timestep of background for DI in [0,nitend-nit000-1] nitdin = ', nitdin
171	WRITE(numout,*) ' Timestep of start of IAU interval in [0,nitend-nit000-1] nitiaustr = ', nitiaustr
172	WRITE(numout,*) ' Timestep of end of IAU interval in [0,nitend-nit000-1] nitiaufin = ', nitiaufin
173	WRITE(numout,*) ' Type of IAU weighting function niaufn = ', niaufn
174	WRITE(numout,*) ' Logical switch for ensuring that the sa > salfixmin ln_salfix = ', ln_salfix
175	WRITE(numout,*) ' Minimum salinity after applying the increments salfixmin = ', salfixmin
176	ENDIF
177
178	nitbkg_r = nitbkg + nit000 - 1 ! Background time referenced to nit000
179	nitdin_r = nitdin + nit000 - 1 ! Background time for DI referenced to nit000
180	nitiaustr_r = nitiaustr + nit000 - 1 ! Start of IAU interval referenced to nit000
181	nitiaufin_r = nitiaufin + nit000 - 1 ! End of IAU interval referenced to nit000
182
183	iiauper = nitiaufin_r - nitiaustr_r + 1 ! IAU interval length
184	icycper = nitend - nit000 + 1 ! Cycle interval length
185
186	CALL calc_date( nitend , ditend_date ) ! Date of final time step
187	CALL calc_date( nitbkg_r , ditbkg_date ) ! Background time for Jb referenced to ndate0
188	CALL calc_date( nitdin_r , ditdin_date ) ! Background time for DI referenced to ndate0
189	CALL calc_date( nitiaustr_r, ditiaustr_date ) ! IAU start time referenced to ndate0
190	CALL calc_date( nitiaufin_r, ditiaufin_date ) ! IAU end time referenced to ndate0
191
192	IF(lwp) THEN
193	WRITE(numout,*)
194	WRITE(numout,*) ' Time steps referenced to current cycle:'
195	WRITE(numout,*) ' iitrst = ', nit000 - 1
196	WRITE(numout,*) ' nit000 = ', nit000
197	WRITE(numout,*) ' nitend = ', nitend
198	WRITE(numout,*) ' nitbkg_r = ', nitbkg_r
199	WRITE(numout,*) ' nitdin_r = ', nitdin_r
200	WRITE(numout,*) ' nitiaustr_r = ', nitiaustr_r
201	WRITE(numout,*) ' nitiaufin_r = ', nitiaufin_r
202	WRITE(numout,*)
203	WRITE(numout,*) ' Dates referenced to current cycle:'
204	WRITE(numout,*) ' ndastp = ', ndastp
205	WRITE(numout,*) ' ndate0 = ', ndate0
206	WRITE(numout,*) ' nn_time0 = ', nn_time0
207	WRITE(numout,*) ' ditend_date = ', ditend_date
208	WRITE(numout,*) ' ditbkg_date = ', ditbkg_date
209	WRITE(numout,*) ' ditdin_date = ', ditdin_date
210	WRITE(numout,*) ' ditiaustr_date = ', ditiaustr_date
211	WRITE(numout,*) ' ditiaufin_date = ', ditiaufin_date
212	ENDIF
213
214
215	IF ( ( ln_asmdin ).AND.( ln_asmiau ) ) &
216	& CALL ctl_stop( ' ln_asmdin and ln_asmiau :', &
217	& ' Choose Direct Initialization OR Incremental Analysis Updating')
218
219	IF ( ( ( .NOT. ln_asmdin ).AND.( .NOT. ln_asmiau ) ) &
220	.AND.( ( ln_trainc ).OR.( ln_dyninc ).OR.( ln_sshinc ) .OR. ( ln_seaiceinc) )) &
221	& CALL ctl_stop( ' One or more of ln_trainc, ln_dyninc, ln_sshinc and ln_seaiceinc is set to .true.', &
222	& ' but ln_asmdin and ln_asmiau are both set to .false. :', &
223	& ' Inconsistent options')
224
225	IF ( ( niaufn /= 0 ).AND.( niaufn /= 1 ) ) &
226	& CALL ctl_stop( ' niaufn /= 0 or niaufn /=1 :', &
227	& ' Type IAU weighting function is invalid')
228
229	IF ( ( .NOT. ln_trainc ).AND.( .NOT. ln_dyninc ).AND.( .NOT. ln_sshinc ).AND.( .NOT. ln_seaiceinc ) &
230	& ) &
231	& CALL ctl_warn( ' ln_trainc, ln_dyninc, ln_sshinc and ln_seaiceinc are set to .false. :', &
232	& ' The assimilation increments are not applied')
233
234	IF ( ( ln_asmiau ).AND.( nitiaustr == nitiaufin ) ) &
235	& CALL ctl_stop( ' nitiaustr = nitiaufin :', &
236	& ' IAU interval is of zero length')
237
238	IF ( ( ln_asmiau ).AND.( ( nitiaustr_r < nit000 ).OR.( nitiaufin_r > nitend ) ) ) &
239	& CALL ctl_stop( ' nitiaustr or nitiaufin :', &
240	& ' IAU starting or final time step is outside the cycle interval', &
241	& ' Valid range nit000 to nitend')
242
243	IF ( ( nitbkg_r < nit000 - 1 ).OR.( nitbkg_r > nitend ) ) &
244	& CALL ctl_stop( ' nitbkg :', &
245	& ' Background time step is outside the cycle interval')
246
247	IF ( ( nitdin_r < nit000 - 1 ).OR.( nitdin_r > nitend ) ) &
248	& CALL ctl_stop( ' nitdin :', &
249	& ' Background time step for Direct Initialization is outside', &
250	& ' the cycle interval')
251
252	IF ( nstop > 0 ) RETURN ! if there are any errors then go no further
253
254	!--------------------------------------------------------------------
255	! Initialize the Incremental Analysis Updating weighting function
256	!--------------------------------------------------------------------
257
258	IF( ln_asmiau ) THEN
259	!
260	ALLOCATE( wgtiau( icycper ) )
261	!
262	wgtiau(:) = 0._wp
263	!
264	! !---------------------------------------------------------
265	IF( niaufn == 0 ) THEN ! Constant IAU forcing
266	! !---------------------------------------------------------
267	DO jt = 1, iiauper
268	wgtiau(jt+nitiaustr-1) = 1.0 / REAL( iiauper )
269	END DO
270	! !---------------------------------------------------------
271	ELSEIF ( niaufn == 1 ) THEN ! Linear hat-like, centred in middle of IAU interval
272	! !---------------------------------------------------------
273	! Compute the normalization factor
274	znorm = 0._wp
275	IF( MOD( iiauper, 2 ) == 0 ) THEN ! Even number of time steps in IAU interval
276	imid = iiauper / 2
277	DO jt = 1, imid
278	znorm = znorm + REAL( jt )
279	END DO
280	znorm = 2.0 * znorm
281	ELSE ! Odd number of time steps in IAU interval
282	imid = ( iiauper + 1 ) / 2
283	DO jt = 1, imid - 1
284	znorm = znorm + REAL( jt )
285	END DO
286	znorm = 2.0 * znorm + REAL( imid )
287	ENDIF
288	znorm = 1.0 / znorm
289	!
290	DO jt = 1, imid - 1
291	wgtiau(jt+nitiaustr-1) = REAL( jt ) * znorm
292	END DO
293	DO jt = imid, iiauper
294	wgtiau(jt+nitiaustr-1) = REAL( iiauper - jt + 1 ) * znorm
295	END DO
296	!
297	ENDIF
298
299	! Test that the integral of the weights over the weighting interval equals 1
300	IF(lwp) THEN
301	WRITE(numout,*)
302	WRITE(numout,*) 'asm_inc_init : IAU weights'
303	WRITE(numout,*) '~~~~~~~~~~~~'
304	WRITE(numout,*) ' time step IAU weight'
305	WRITE(numout,*) ' ========= ====================='
306	ztotwgt = 0.0
307	DO jt = 1, icycper
308	ztotwgt = ztotwgt + wgtiau(jt)
309	WRITE(numout,*) ' ', jt, ' ', wgtiau(jt)
310	END DO
311	WRITE(numout,*) ' ==================================='
312	WRITE(numout,*) ' Time-integrated weight = ', ztotwgt
313	WRITE(numout,*) ' ==================================='
314	ENDIF
315
316	ENDIF
317
318	!--------------------------------------------------------------------
319	! Allocate and initialize the increment arrays
320	!--------------------------------------------------------------------
321
322	ALLOCATE( t_bkginc (jpi,jpj,jpk) ) ; t_bkginc (:,:,:) = 0._wp
323	ALLOCATE( s_bkginc (jpi,jpj,jpk) ) ; s_bkginc (:,:,:) = 0._wp
324	ALLOCATE( u_bkginc (jpi,jpj,jpk) ) ; u_bkginc (:,:,:) = 0._wp
325	ALLOCATE( v_bkginc (jpi,jpj,jpk) ) ; v_bkginc (:,:,:) = 0._wp
326	ALLOCATE( ssh_bkginc (jpi,jpj) ) ; ssh_bkginc (:,:) = 0._wp
327	ALLOCATE( seaice_bkginc(jpi,jpj) ) ; seaice_bkginc(:,:) = 0._wp
328	#if defined key_asminc
329	ALLOCATE( ssh_iau (jpi,jpj) ) ; ssh_iau (:,:) = 0._wp
330	#endif
331	#if defined key_cice && defined key_asminc
332	ALLOCATE( ndaice_da (jpi,jpj) ) ; ndaice_da (:,:) = 0._wp
333	#endif
334	!
335	IF ( ln_trainc .OR. ln_dyninc .OR. & !--------------------------------------
336	& ln_sshinc .OR. ln_seaiceinc ) THEN ! Read the increments from file
337	! !--------------------------------------
338	CALL iom_open( c_asminc, inum )
339	!
340	CALL iom_get( inum, 'time' , zdate_inc )
341	CALL iom_get( inum, 'z_inc_dateb', z_inc_dateb )
342	CALL iom_get( inum, 'z_inc_datef', z_inc_datef )
343	z_inc_dateb = zdate_inc
344	z_inc_datef = zdate_inc
345	!
346	IF(lwp) THEN
347	WRITE(numout,*)
348	WRITE(numout,*) 'asm_inc_init : Assimilation increments valid between dates ', z_inc_dateb,' and ', z_inc_datef
349	WRITE(numout,*) '~~~~~~~~~~~~'
350	ENDIF
351	!
352	IF ( ( z_inc_dateb < ndastp + nn_time0*0.0001_wp ) .OR. &
353	& ( z_inc_datef > ditend_date ) ) &
354	& CALL ctl_warn( ' Validity time of assimilation increments is ', &
355	& ' outside the assimilation interval' )
356
357	IF ( ( ln_asmdin ).AND.( zdate_inc /= ditdin_date ) ) &
358	& CALL ctl_warn( ' Validity time of assimilation increments does ', &
359	& ' not agree with Direct Initialization time' )
360
361	IF ( ln_trainc ) THEN
362	CALL iom_get( inum, jpdom_autoglo, 'bckint', t_bkginc, 1 )
363	CALL iom_get( inum, jpdom_autoglo, 'bckins', s_bkginc, 1 )
364	! Apply the masks
365	t_bkginc(:,:,:) = t_bkginc(:,:,:) * tmask(:,:,:)
366	s_bkginc(:,:,:) = s_bkginc(:,:,:) * tmask(:,:,:)
367	! Set missing increments to 0.0 rather than 1e+20
368	! to allow for differences in masks
369	WHERE( ABS( t_bkginc(:,:,:) ) > 1.0e+10 ) t_bkginc(:,:,:) = 0.0
370	WHERE( ABS( s_bkginc(:,:,:) ) > 1.0e+10 ) s_bkginc(:,:,:) = 0.0
371	ENDIF
372
373	IF ( ln_dyninc ) THEN
374	CALL iom_get( inum, jpdom_autoglo, 'bckinu', u_bkginc, 1 )
375	CALL iom_get( inum, jpdom_autoglo, 'bckinv', v_bkginc, 1 )
376	! Apply the masks
377	u_bkginc(:,:,:) = u_bkginc(:,:,:) * umask(:,:,:)
378	v_bkginc(:,:,:) = v_bkginc(:,:,:) * vmask(:,:,:)
379	! Set missing increments to 0.0 rather than 1e+20
380	! to allow for differences in masks
381	WHERE( ABS( u_bkginc(:,:,:) ) > 1.0e+10 ) u_bkginc(:,:,:) = 0.0
382	WHERE( ABS( v_bkginc(:,:,:) ) > 1.0e+10 ) v_bkginc(:,:,:) = 0.0
383	ENDIF
384
385	IF ( ln_sshinc ) THEN
386	CALL iom_get( inum, jpdom_autoglo, 'bckineta', ssh_bkginc, 1 )
387	! Apply the masks
388	ssh_bkginc(:,:) = ssh_bkginc(:,:) * tmask(:,:,1)
389	! Set missing increments to 0.0 rather than 1e+20
390	! to allow for differences in masks
391	WHERE( ABS( ssh_bkginc(:,:) ) > 1.0e+10 ) ssh_bkginc(:,:) = 0.0
392	ENDIF
393
394	IF ( ln_seaiceinc ) THEN
395	CALL iom_get( inum, jpdom_autoglo, 'bckinseaice', seaice_bkginc, 1 )
396	! Apply the masks
397	seaice_bkginc(:,:) = seaice_bkginc(:,:) * tmask(:,:,1)
398	! Set missing increments to 0.0 rather than 1e+20
399	! to allow for differences in masks
400	WHERE( ABS( seaice_bkginc(:,:) ) > 1.0e+10 ) seaice_bkginc(:,:) = 0.0
401	ENDIF
402	!
403	CALL iom_close( inum )
404	!
405	ENDIF
406	!
407	! !--------------------------------------
408	IF ( ln_dyninc .AND. nn_divdmp > 0 ) THEN ! Apply divergence damping filter
409	! !--------------------------------------
410	ALLOCATE( zhdiv(jpi,jpj) )
411	!
412	DO jt = 1, nn_divdmp
413	!
414	DO jk = 1, jpkm1 ! zhdiv = e1e1 * div
415	zhdiv(:,:) = 0._wp
416	DO jj = 2, jpjm1
417	DO ji = fs_2, fs_jpim1 ! vector opt.
418	zhdiv(ji,jj) = ( e2u(ji ,jj) * e3u_n(ji ,jj,jk) * u_bkginc(ji ,jj,jk) &
419	& - e2u(ji-1,jj) * e3u_n(ji-1,jj,jk) * u_bkginc(ji-1,jj,jk) &
420	& + e1v(ji,jj ) * e3v_n(ji,jj ,jk) * v_bkginc(ji,jj ,jk) &
421	& - e1v(ji,jj-1) * e3v_n(ji,jj-1,jk) * v_bkginc(ji,jj-1,jk) ) / e3t_n(ji,jj,jk)
422	END DO
423	END DO
424	CALL lbc_lnk( 'asminc', zhdiv, 'T', 1. ) ! lateral boundary cond. (no sign change)
425	!
426	DO jj = 2, jpjm1
427	DO ji = fs_2, fs_jpim1 ! vector opt.
428	u_bkginc(ji,jj,jk) = u_bkginc(ji,jj,jk) &
429	& + 0.2_wp * ( zhdiv(ji+1,jj) - zhdiv(ji ,jj) ) * r1_e1u(ji,jj) * umask(ji,jj,jk)
430	v_bkginc(ji,jj,jk) = v_bkginc(ji,jj,jk) &
431	& + 0.2_wp * ( zhdiv(ji,jj+1) - zhdiv(ji,jj ) ) * r1_e2v(ji,jj) * vmask(ji,jj,jk)
432	END DO
433	END DO
434	END DO
435	!
436	END DO
437	!
438	DEALLOCATE( zhdiv )
439	!
440	ENDIF
441	!
442	! !-----------------------------------------------------
443	IF ( ln_asmdin ) THEN ! Allocate and initialize the background state arrays
444	! !-----------------------------------------------------
445	!
446	ALLOCATE( t_bkg (jpi,jpj,jpk) ) ; t_bkg (:,:,:) = 0._wp
447	ALLOCATE( s_bkg (jpi,jpj,jpk) ) ; s_bkg (:,:,:) = 0._wp
448	ALLOCATE( u_bkg (jpi,jpj,jpk) ) ; u_bkg (:,:,:) = 0._wp
449	ALLOCATE( v_bkg (jpi,jpj,jpk) ) ; v_bkg (:,:,:) = 0._wp
450	ALLOCATE( ssh_bkg(jpi,jpj) ) ; ssh_bkg(:,:) = 0._wp
451	!
452	!
453	!--------------------------------------------------------------------
454	! Read from file the background state at analysis time
455	!--------------------------------------------------------------------
456	!
457	CALL iom_open( c_asmdin, inum )
458	!
459	CALL iom_get( inum, 'rdastp', zdate_bkg )
460	!
461	IF(lwp) THEN
462	WRITE(numout,*)
463	WRITE(numout,*) ' ==>>> Assimilation background state valid at : ', zdate_bkg
464	WRITE(numout,*)
465	ENDIF
466	!
467	IF ( zdate_bkg /= ditdin_date ) &
468	& CALL ctl_warn( ' Validity time of assimilation background state does', &
469	& ' not agree with Direct Initialization time' )
470	!
471	IF ( ln_trainc ) THEN
472	CALL iom_get( inum, jpdom_autoglo, 'tn', t_bkg )
473	CALL iom_get( inum, jpdom_autoglo, 'sn', s_bkg )
474	t_bkg(:,:,:) = t_bkg(:,:,:) * tmask(:,:,:)
475	s_bkg(:,:,:) = s_bkg(:,:,:) * tmask(:,:,:)
476	ENDIF
477	!
478	IF ( ln_dyninc ) THEN
479	CALL iom_get( inum, jpdom_autoglo, 'un', u_bkg )
480	CALL iom_get( inum, jpdom_autoglo, 'vn', v_bkg )
481	u_bkg(:,:,:) = u_bkg(:,:,:) * umask(:,:,:)
482	v_bkg(:,:,:) = v_bkg(:,:,:) * vmask(:,:,:)
483	ENDIF
484	!
485	IF ( ln_sshinc ) THEN
486	CALL iom_get( inum, jpdom_autoglo, 'sshn', ssh_bkg )
487	ssh_bkg(:,:) = ssh_bkg(:,:) * tmask(:,:,1)
488	ENDIF
489	!
490	CALL iom_close( inum )
491	!
492	ENDIF
493	!
494	IF(lwp) WRITE(numout,*) ' ==>>> Euler time step switch is ', neuler
495	!
496	IF( lk_asminc ) THEN !== data assimilation ==!
497	IF( ln_bkgwri ) CALL asm_bkg_wri( nit000 - 1 ) ! Output background fields
498	IF( ln_asmdin ) THEN ! Direct initialization
499	IF( ln_trainc ) CALL tra_asm_inc( nit000 - 1, Kmm ) ! Tracers
500	IF( ln_dyninc ) CALL dyn_asm_inc( nit000 - 1 ) ! Dynamics
501	IF( ln_sshinc ) CALL ssh_asm_inc( nit000 - 1 ) ! SSH
502	ENDIF
503	ENDIF
504	!
505	END SUBROUTINE asm_inc_init
506
507
508	SUBROUTINE tra_asm_inc( kt, Kmm )
509	!!----------------------------------------------------------------------
510	!! * ROUTINE tra_asm_inc *
511	!!
512	!! ** Purpose : Apply the tracer (T and S) assimilation increments
513	!!
514	!! ** Method : Direct initialization or Incremental Analysis Updating
515	!!
516	!! ** Action :
517	!!----------------------------------------------------------------------
518	INTEGER, INTENT(IN) :: kt ! Current time step
519	INTEGER, INTENT(IN) :: Kmm ! Current time level index
520	!
521	INTEGER :: ji, jj, jk
522	INTEGER :: it
523	REAL(wp) :: zincwgt ! IAU weight for current time step
524	REAL (wp), DIMENSION(jpi,jpj,jpk) :: fzptnz ! 3d freezing point values
525	!!----------------------------------------------------------------------
526	!
527	! freezing point calculation taken from oc_fz_pt (but calculated for all depths)
528	! used to prevent the applied increments taking the temperature below the local freezing point
529	DO jk = 1, jpkm1
530	CALL eos_fzp( tsn(:,:,jk,jp_sal), fzptnz(:,:,jk), gdept_n(:,:,jk) )
531	END DO
532	!
533	! !--------------------------------------
534	IF ( ln_asmiau ) THEN ! Incremental Analysis Updating
535	! !--------------------------------------
536	!
537	IF ( ( kt >= nitiaustr_r ).AND.( kt <= nitiaufin_r ) ) THEN
538	!
539	it = kt - nit000 + 1
540	zincwgt = wgtiau(it) / rdt ! IAU weight for the current time step
541	!
542	IF(lwp) THEN
543	WRITE(numout,*)
544	WRITE(numout,*) 'tra_asm_inc : Tracer IAU at time step = ', kt,' with IAU weight = ', wgtiau(it)
545	WRITE(numout,*) '~~~~~~~~~~~~'
546	ENDIF
547	!
548	! Update the tracer tendencies
549	DO jk = 1, jpkm1
550	IF (ln_temnofreeze) THEN
551	! Do not apply negative increments if the temperature will fall below freezing
552	WHERE(t_bkginc(:,:,jk) > 0.0_wp .OR. &
553	& tsn(:,:,jk,jp_tem) + tsa(:,:,jk,jp_tem) + t_bkginc(:,:,jk) * wgtiau(it) > fzptnz(:,:,jk) )
554	tsa(:,:,jk,jp_tem) = tsa(:,:,jk,jp_tem) + t_bkginc(:,:,jk) * zincwgt
555	END WHERE
556	ELSE
557	tsa(:,:,jk,jp_tem) = tsa(:,:,jk,jp_tem) + t_bkginc(:,:,jk) * zincwgt
558	ENDIF
559	IF (ln_salfix) THEN
560	! Do not apply negative increments if the salinity will fall below a specified
561	! minimum value salfixmin
562	WHERE(s_bkginc(:,:,jk) > 0.0_wp .OR. &
563	& tsn(:,:,jk,jp_sal) + tsa(:,:,jk,jp_sal) + s_bkginc(:,:,jk) * wgtiau(it) > salfixmin )
564	tsa(:,:,jk,jp_sal) = tsa(:,:,jk,jp_sal) + s_bkginc(:,:,jk) * zincwgt
565	END WHERE
566	ELSE
567	tsa(:,:,jk,jp_sal) = tsa(:,:,jk,jp_sal) + s_bkginc(:,:,jk) * zincwgt
568	ENDIF
569	END DO
570	!
571	ENDIF
572	!
573	IF ( kt == nitiaufin_r + 1 ) THEN ! For bias crcn to work
574	DEALLOCATE( t_bkginc )
575	DEALLOCATE( s_bkginc )
576	ENDIF
577	! !--------------------------------------
578	ELSEIF ( ln_asmdin ) THEN ! Direct Initialization
579	! !--------------------------------------
580	!
581	IF ( kt == nitdin_r ) THEN
582	!
583	neuler = 0 ! Force Euler forward step
584	!
585	! Initialize the now fields with the background + increment
586	IF (ln_temnofreeze) THEN
587	! Do not apply negative increments if the temperature will fall below freezing
588	WHERE( t_bkginc(:,:,:) > 0.0_wp .OR. tsn(:,:,:,jp_tem) + t_bkginc(:,:,:) > fzptnz(:,:,:) )
589	tsn(:,:,:,jp_tem) = t_bkg(:,:,:) + t_bkginc(:,:,:)
590	END WHERE
591	ELSE
592	tsn(:,:,:,jp_tem) = t_bkg(:,:,:) + t_bkginc(:,:,:)
593	ENDIF
594	IF (ln_salfix) THEN
595	! Do not apply negative increments if the salinity will fall below a specified
596	! minimum value salfixmin
597	WHERE( s_bkginc(:,:,:) > 0.0_wp .OR. tsn(:,:,:,jp_sal) + s_bkginc(:,:,:) > salfixmin )
598	tsn(:,:,:,jp_sal) = s_bkg(:,:,:) + s_bkginc(:,:,:)
599	END WHERE
600	ELSE
601	tsn(:,:,:,jp_sal) = s_bkg(:,:,:) + s_bkginc(:,:,:)
602	ENDIF
603
604	tsb(:,:,:,:) = tsn(:,:,:,:) ! Update before fields
605
606	CALL eos( tsb, rhd, rhop, gdept_0(:,:,:) ) ! Before potential and in situ densities
607	!!gm fabien
608	! CALL eos( tsb, rhd, rhop ) ! Before potential and in situ densities
609	!!gm
610
611	IF( ln_zps .AND. .NOT. lk_c1d .AND. .NOT. ln_isfcav) &
612	& CALL zps_hde ( kt, Kmm, jpts, tsb, gtsu, gtsv, & ! Partial steps: before horizontal gradient
613	& rhd, gru , grv ) ! of t, s, rd at the last ocean level
614	IF( ln_zps .AND. .NOT. lk_c1d .AND. ln_isfcav) &
615	& CALL zps_hde_isf( nit000, Kmm, jpts, tsb, gtsu, gtsv, gtui, gtvi, & ! Partial steps for top cell (ISF)
616	& rhd, gru , grv , grui, grvi ) ! of t, s, rd at the last ocean level
617
618	DEALLOCATE( t_bkginc )
619	DEALLOCATE( s_bkginc )
620	DEALLOCATE( t_bkg )
621	DEALLOCATE( s_bkg )
622	ENDIF
623	!
624	ENDIF
625	! Perhaps the following call should be in step
626	IF ( ln_seaiceinc ) CALL seaice_asm_inc ( kt ) ! apply sea ice concentration increment
627	!
628	END SUBROUTINE tra_asm_inc
629
630
631	SUBROUTINE dyn_asm_inc( kt )
632	!!----------------------------------------------------------------------
633	!! * ROUTINE dyn_asm_inc *
634	!!
635	!! ** Purpose : Apply the dynamics (u and v) assimilation increments.
636	!!
637	!! ** Method : Direct initialization or Incremental Analysis Updating.
638	!!
639	!! ** Action :
640	!!----------------------------------------------------------------------
641	INTEGER, INTENT(IN) :: kt ! Current time step
642	!
643	INTEGER :: jk
644	INTEGER :: it
645	REAL(wp) :: zincwgt ! IAU weight for current time step
646	!!----------------------------------------------------------------------
647	!
648	! !--------------------------------------------
649	IF ( ln_asmiau ) THEN ! Incremental Analysis Updating
650	! !--------------------------------------------
651	!
652	IF ( ( kt >= nitiaustr_r ).AND.( kt <= nitiaufin_r ) ) THEN
653	!
654	it = kt - nit000 + 1
655	zincwgt = wgtiau(it) / rdt ! IAU weight for the current time step
656	!
657	IF(lwp) THEN
658	WRITE(numout,*)
659	WRITE(numout,*) 'dyn_asm_inc : Dynamics IAU at time step = ', kt,' with IAU weight = ', wgtiau(it)
660	WRITE(numout,*) '~~~~~~~~~~~~'
661	ENDIF
662	!
663	! Update the dynamic tendencies
664	DO jk = 1, jpkm1
665	ua(:,:,jk) = ua(:,:,jk) + u_bkginc(:,:,jk) * zincwgt
666	va(:,:,jk) = va(:,:,jk) + v_bkginc(:,:,jk) * zincwgt
667	END DO
668	!
669	IF ( kt == nitiaufin_r ) THEN
670	DEALLOCATE( u_bkginc )
671	DEALLOCATE( v_bkginc )
672	ENDIF
673	!
674	ENDIF
675	! !-----------------------------------------
676	ELSEIF ( ln_asmdin ) THEN ! Direct Initialization
677	! !-----------------------------------------
678	!
679	IF ( kt == nitdin_r ) THEN
680	!
681	neuler = 0 ! Force Euler forward step
682	!
683	! Initialize the now fields with the background + increment
684	un(:,:,:) = u_bkg(:,:,:) + u_bkginc(:,:,:)
685	vn(:,:,:) = v_bkg(:,:,:) + v_bkginc(:,:,:)
686	!
687	ub(:,:,:) = un(:,:,:) ! Update before fields
688	vb(:,:,:) = vn(:,:,:)
689	!
690	DEALLOCATE( u_bkg )
691	DEALLOCATE( v_bkg )
692	DEALLOCATE( u_bkginc )
693	DEALLOCATE( v_bkginc )
694	ENDIF
695	!
696	ENDIF
697	!
698	END SUBROUTINE dyn_asm_inc
699
700
701	SUBROUTINE ssh_asm_inc( kt )
702	!!----------------------------------------------------------------------
703	!! * ROUTINE ssh_asm_inc *
704	!!
705	!! ** Purpose : Apply the sea surface height assimilation increment.
706	!!
707	!! ** Method : Direct initialization or Incremental Analysis Updating.
708	!!
709	!! ** Action :
710	!!----------------------------------------------------------------------
711	INTEGER, INTENT(IN) :: kt ! Current time step
712	!
713	INTEGER :: it
714	INTEGER :: jk
715	REAL(wp) :: zincwgt ! IAU weight for current time step
716	!!----------------------------------------------------------------------
717	!
718	! !-----------------------------------------
719	IF ( ln_asmiau ) THEN ! Incremental Analysis Updating
720	! !-----------------------------------------
721	!
722	IF ( ( kt >= nitiaustr_r ).AND.( kt <= nitiaufin_r ) ) THEN
723	!
724	it = kt - nit000 + 1
725	zincwgt = wgtiau(it) / rdt ! IAU weight for the current time step
726	!
727	IF(lwp) THEN
728	WRITE(numout,*)
729	WRITE(numout,*) 'ssh_asm_inc : SSH IAU at time step = ', &
730	& kt,' with IAU weight = ', wgtiau(it)
731	WRITE(numout,*) '~~~~~~~~~~~~'
732	ENDIF
733	!
734	! Save the tendency associated with the IAU weighted SSH increment
735	! (applied in dynspg.*)
736	#if defined key_asminc
737	ssh_iau(:,:) = ssh_bkginc(:,:) * zincwgt
738	#endif
739	!
740	ELSE IF( kt == nitiaufin_r+1 ) THEN
741	!
742	! test on ssh_bkginc needed as ssh_asm_inc is called twice by time step
743	IF (ALLOCATED(ssh_bkginc)) DEALLOCATE( ssh_bkginc )
744	!
745	#if defined key_asminc
746	ssh_iau(:,:) = 0._wp
747	#endif
748	!
749	ENDIF
750	! !-----------------------------------------
751	ELSEIF ( ln_asmdin ) THEN ! Direct Initialization
752	! !-----------------------------------------
753	!
754	IF ( kt == nitdin_r ) THEN
755	!
756	neuler = 0 ! Force Euler forward step
757	!
758	sshn(:,:) = ssh_bkg(:,:) + ssh_bkginc(:,:) ! Initialize the now fields the background + increment
759	!
760	sshb(:,:) = sshn(:,:) ! Update before fields
761	e3t_b(:,:,:) = e3t_n(:,:,:)
762	!!gm why not e3u_b, e3v_b, gdept_b ????
763	!
764	DEALLOCATE( ssh_bkg )
765	DEALLOCATE( ssh_bkginc )
766	!
767	ENDIF
768	!
769	ENDIF
770	!
771	END SUBROUTINE ssh_asm_inc
772
773
774	SUBROUTINE ssh_asm_div( kt, phdivn )
775	!!----------------------------------------------------------------------
776	!! * ROUTINE ssh_asm_div *
777	!!
778	!! ** Purpose : ssh increment with z* is incorporated via a correction of the local divergence
779	!! across all the water column
780	!!
781	!! ** Method :
782	!! CAUTION : sshiau is positive (inflow) decreasing the
783	!! divergence and expressed in m/s
784	!!
785	!! ** Action : phdivn decreased by the ssh increment
786	!!----------------------------------------------------------------------
787	INTEGER, INTENT(IN) :: kt ! ocean time-step index
788	REAL(wp), DIMENSION(:,:,:), INTENT(inout) :: phdivn ! horizontal divergence
789	!!
790	INTEGER :: jk ! dummy loop index
791	REAL(wp), DIMENSION(:,:) , POINTER :: ztim ! local array
792	!!----------------------------------------------------------------------
793	!
794	#if defined key_asminc
795	CALL ssh_asm_inc( kt ) !== (calculate increments)
796	!
797	IF( ln_linssh ) THEN
798	phdivn(:,:,1) = phdivn(:,:,1) - ssh_iau(:,:) / e3t_n(:,:,1) * tmask(:,:,1)
799	ELSE
800	ALLOCATE( ztim(jpi,jpj) )
801	ztim(:,:) = ssh_iau(:,:) / ( ht_n(:,:) + 1.0 - ssmask(:,:) )
802	DO jk = 1, jpkm1
803	phdivn(:,:,jk) = phdivn(:,:,jk) - ztim(:,:) * tmask(:,:,jk)
804	END DO
805	!
806	DEALLOCATE(ztim)
807	ENDIF
808	#endif
809	!
810	END SUBROUTINE ssh_asm_div
811
812
813	SUBROUTINE seaice_asm_inc( kt, kindic )
814	!!----------------------------------------------------------------------
815	!! * ROUTINE seaice_asm_inc *
816	!!
817	!! ** Purpose : Apply the sea ice assimilation increment.
818	!!
819	!! ** Method : Direct initialization or Incremental Analysis Updating.
820	!!
821	!! ** Action :
822	!!
823	!!----------------------------------------------------------------------
824	INTEGER, INTENT(in) :: kt ! Current time step
825	INTEGER, INTENT(in), OPTIONAL :: kindic ! flag for disabling the deallocation
826	!
827	INTEGER :: it
828	REAL(wp) :: zincwgt ! IAU weight for current time step
829	#if defined key_si3
830	REAL(wp), DIMENSION(jpi,jpj) :: zofrld, zohicif, zseaicendg, zhicifinc
831	REAL(wp) :: zhicifmin = 0.5_wp ! ice minimum depth in metres
832	#endif
833	!!----------------------------------------------------------------------
834	!
835	! !-----------------------------------------
836	IF ( ln_asmiau ) THEN ! Incremental Analysis Updating
837	! !-----------------------------------------
838	!
839	IF ( ( kt >= nitiaustr_r ).AND.( kt <= nitiaufin_r ) ) THEN
840	!
841	it = kt - nit000 + 1
842	zincwgt = wgtiau(it) ! IAU weight for the current time step
843	! note this is not a tendency so should not be divided by rdt (as with the tracer and other increments)
844	!
845	IF(lwp) THEN
846	WRITE(numout,*)
847	WRITE(numout,*) 'seaice_asm_inc : sea ice conc IAU at time step = ', kt,' with IAU weight = ', wgtiau(it)
848	WRITE(numout,*) '~~~~~~~~~~~~'
849	ENDIF
850	!
851	! Sea-ice : SI3 case
852	!
853	#if defined key_si3
854	zofrld (:,:) = 1._wp - at_i(:,:)
855	zohicif(:,:) = hm_i(:,:)
856	!
857	at_i (:,:) = 1. - MIN( MAX( 1.-at_i (:,:) - seaice_bkginc(:,:) * zincwgt, 0.0_wp), 1.0_wp)
858	at_i_b(:,:) = 1. - MIN( MAX( 1.-at_i_b(:,:) - seaice_bkginc(:,:) * zincwgt, 0.0_wp), 1.0_wp)
859	fr_i(:,:) = at_i(:,:) ! adjust ice fraction
860	!
861	zseaicendg(:,:) = zofrld(:,:) - (1. - at_i(:,:)) ! find out actual sea ice nudge applied
862	!
863	! Nudge sea ice depth to bring it up to a required minimum depth
864	WHERE( zseaicendg(:,:) > 0.0_wp .AND. hm_i(:,:) < zhicifmin )
865	zhicifinc(:,:) = (zhicifmin - hm_i(:,:)) * zincwgt
866	ELSEWHERE
867	zhicifinc(:,:) = 0.0_wp
868	END WHERE
869	!
870	! nudge ice depth
871	hm_i (:,:) = hm_i (:,:) + zhicifinc(:,:)
872	!
873	! seaice salinity balancing (to add)
874	#endif
875	!
876	#if defined key_cice && defined key_asminc
877	! Sea-ice : CICE case. Pass ice increment tendency into CICE
878	ndaice_da(:,:) = seaice_bkginc(:,:) * zincwgt / rdt
879	#endif
880	!
881	IF ( kt == nitiaufin_r ) THEN
882	DEALLOCATE( seaice_bkginc )
883	ENDIF
884	!
885	ELSE
886	!
887	#if defined key_cice && defined key_asminc
888	ndaice_da(:,:) = 0._wp ! Sea-ice : CICE case. Zero ice increment tendency into CICE
889	#endif
890	!
891	ENDIF
892	! !-----------------------------------------
893	ELSEIF ( ln_asmdin ) THEN ! Direct Initialization
894	! !-----------------------------------------
895	!
896	IF ( kt == nitdin_r ) THEN
897	!
898	neuler = 0 ! Force Euler forward step
899	!
900	! Sea-ice : SI3 case
901	!
902	#if defined key_si3
903	zofrld (:,:) = 1._wp - at_i(:,:)
904	zohicif(:,:) = hm_i(:,:)
905	!
906	! Initialize the now fields the background + increment
907	at_i(:,:) = 1. - MIN( MAX( 1.-at_i(:,:) - seaice_bkginc(:,:), 0.0_wp), 1.0_wp)
908	at_i_b(:,:) = at_i(:,:)
909	fr_i(:,:) = at_i(:,:) ! adjust ice fraction
910	!
911	zseaicendg(:,:) = zofrld(:,:) - (1. - at_i(:,:)) ! find out actual sea ice nudge applied
912	!
913	! Nudge sea ice depth to bring it up to a required minimum depth
914	WHERE( zseaicendg(:,:) > 0.0_wp .AND. hm_i(:,:) < zhicifmin )
915	zhicifinc(:,:) = zhicifmin - hm_i(:,:)
916	ELSEWHERE
917	zhicifinc(:,:) = 0.0_wp
918	END WHERE
919	!
920	! nudge ice depth
921	hm_i (:,:) = hm_i (:,:) + zhicifinc(:,:)
922	!
923	! seaice salinity balancing (to add)
924	#endif
925	!
926	#if defined key_cice && defined key_asminc
927	! Sea-ice : CICE case. Pass ice increment tendency into CICE
928	ndaice_da(:,:) = seaice_bkginc(:,:) / rdt
929	#endif
930	IF ( .NOT. PRESENT(kindic) ) THEN
931	DEALLOCATE( seaice_bkginc )
932	END IF
933	!
934	ELSE
935	!
936	#if defined key_cice && defined key_asminc
937	ndaice_da(:,:) = 0._wp ! Sea-ice : CICE case. Zero ice increment tendency into CICE
938	#endif
939	!
940	ENDIF
941
942	!#if defined defined key_si3 \|\| defined key_cice
943	!
944	! IF (ln_seaicebal ) THEN
945	! !! balancing salinity increments
946	! !! simple case from limflx.F90 (doesn't include a mass flux)
947	! !! assumption is that as ice concentration is reduced or increased
948	! !! the snow and ice depths remain constant
949	! !! note that snow is being created where ice concentration is being increased
950	! !! - could be more sophisticated and
951	! !! not do this (but would need to alter h_snow)
952	!
953	! usave(:,:,:)=sb(:,:,:) ! use array as a temporary store
954	!
955	! DO jj = 1, jpj
956	! DO ji = 1, jpi
957	! ! calculate change in ice and snow mass per unit area
958	! ! positive values imply adding salt to the ocean (results from ice formation)
959	! ! fwf : ice formation and melting
960	!
961	! zfons = ( -nfresh_da(ji,jj)soce + nfsalt_da(ji,jj) )rdt
962	!
963	! ! change salinity down to mixed layer depth
964	! mld=hmld_kara(ji,jj)
965	!
966	! ! prevent small mld
967	! ! less than 10m can cause salinity instability
968	! IF (mld < 10) mld=10
969	!
970	! ! set to bottom of a level
971	! DO jk = jpk-1, 2, -1
972	! IF ((mld > gdepw(ji,jj,jk)) .and. (mld < gdepw(ji,jj,jk+1))) THEN
973	! mld=gdepw(ji,jj,jk+1)
974	! jkmax=jk
975	! ENDIF
976	! ENDDO
977	!
978	! ! avoid applying salinity balancing in shallow water or on land
979	! !
980	!
981	! ! dsal_ocn (psu kg m^-2) / (kg m^-3 * m)
982	!
983	! dsal_ocn=0.0_wp
984	! sal_thresh=5.0_wp ! minimum salinity threshold for salinity balancing
985	!
986	! if (tmask(ji,jj,1) > 0 .AND. tmask(ji,jj,jkmax) > 0 ) &
987	! dsal_ocn = zfons / (rhop(ji,jj,1) * mld)
988	!
989	! ! put increments in for levels in the mixed layer
990	! ! but prevent salinity below a threshold value
991	!
992	! DO jk = 1, jkmax
993	!
994	! IF (dsal_ocn > 0.0_wp .or. sb(ji,jj,jk)+dsal_ocn > sal_thresh) THEN
995	! sb(ji,jj,jk) = sb(ji,jj,jk) + dsal_ocn
996	! sn(ji,jj,jk) = sn(ji,jj,jk) + dsal_ocn
997	! ENDIF
998	!
999	! ENDDO
1000	!
1001	! ! ! salt exchanges at the ice/ocean interface
1002	! ! zpmess = zfons / rdt_ice ! rdt_ice is ice timestep
1003	! !
1004	! !! Adjust fsalt. A +ve fsalt means adding salt to ocean
1005	! !! fsalt(ji,jj) = fsalt(ji,jj) + zpmess ! adjust fsalt
1006	! !!
1007	! !! emps(ji,jj) = emps(ji,jj) + zpmess ! or adjust emps (see icestp1d)
1008	! !! ! E-P (kg m-2 s-2)
1009	! ! emp(ji,jj) = emp(ji,jj) + zpmess ! E-P (kg m-2 s-2)
1010	! ENDDO !ji
1011	! ENDDO !jj!
1012	!
1013	! ENDIF !ln_seaicebal
1014	!
1015	!#endif
1016	!
1017	ENDIF
1018	!
1019	END SUBROUTINE seaice_asm_inc
1020
1021	!!======================================================================
1022	END MODULE asminc

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