source: LMDZ5/branches/IPSLCM5A2.1_ISO/libf/phyiso/ocean_slab_mod.F90 @ 3331

Last change on this file since 3331 was 3331, checked in by acozic, 6 years ago

Add modification for isotopes

  • Property svn:executable set to *
File size: 28.7 KB
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1!
2MODULE ocean_slab_mod
3!
4! This module is used for both surface ocean and sea-ice when using the slab ocean,
5! "ocean=slab".
6!
7
8  USE dimphy
9  USE indice_sol_mod
10  USE surface_data
11
12  IMPLICIT NONE
13  PRIVATE
14  PUBLIC :: ocean_slab_init, ocean_slab_frac, ocean_slab_noice, ocean_slab_ice
15
16!****************************************************************************************
17! Global saved variables
18!****************************************************************************************
19
20  INTEGER, PRIVATE, SAVE                           :: cpl_pas
21  !$OMP THREADPRIVATE(cpl_pas)
22  REAL, PRIVATE, SAVE                              :: cyang
23  !$OMP THREADPRIVATE(cyang)
24  REAL, ALLOCATABLE, DIMENSION(:), PRIVATE, SAVE   :: slabh
25  !$OMP THREADPRIVATE(slabh)
26  REAL, ALLOCATABLE, DIMENSION(:,:), PUBLIC, SAVE   :: tslab
27  !$OMP THREADPRIVATE(tslab)
28  REAL, ALLOCATABLE, DIMENSION(:), PUBLIC, SAVE  :: fsic
29  !$OMP THREADPRIVATE(fsic)
30  REAL, ALLOCATABLE, DIMENSION(:), PUBLIC, SAVE  :: tice
31  !$OMP THREADPRIVATE(tice)
32  REAL, ALLOCATABLE, DIMENSION(:), PUBLIC, SAVE  :: seaice
33  !$OMP THREADPRIVATE(seaice)
34  REAL, ALLOCATABLE, DIMENSION(:), PUBLIC, SAVE  :: slab_bils
35  !$OMP THREADPRIVATE(slab_bils)
36  REAL, ALLOCATABLE, DIMENSION(:), PRIVATE, SAVE  :: bils_cum
37  !$OMP THREADPRIVATE(bils_cum)
38  REAL, ALLOCATABLE, DIMENSION(:), PUBLIC, SAVE  :: slab_bilg
39  !$OMP THREADPRIVATE(slab_bilg)
40  REAL, ALLOCATABLE, DIMENSION(:), PRIVATE, SAVE  :: bilg_cum
41  !$OMP THREADPRIVATE(bilg_cum)
42
43!****************************************************************************************
44! Parameters (could be read in def file: move to slab_init)
45!****************************************************************************************
46! snow and ice physical characteristics:
47    REAL, PARAMETER :: t_freeze=271.35 ! freezing sea water temp
48    REAL, PARAMETER :: t_melt=273.15   ! melting ice temp
49    REAL, PARAMETER :: sno_den=300. !mean snow density, kg/m3
50    REAL, PARAMETER :: ice_den=917.
51    REAL, PARAMETER :: sea_den=1025.
52    REAL, PARAMETER :: ice_cond=2.17*ice_den !conductivity
53    REAL, PARAMETER :: sno_cond=0.31*sno_den
54    REAL, PARAMETER :: ice_cap=2067.   ! specific heat capacity, snow and ice
55    REAL, PARAMETER :: ice_lat=334000. ! freeze /melt latent heat snow and ice
56
57! control of snow and ice cover & freeze / melt (heights converted to kg/m2)
58    REAL, PARAMETER :: snow_min=0.05*sno_den !critical snow height 5 cm
59    REAL, PARAMETER :: snow_wfact=0.4 ! max fraction of falling snow blown into ocean
60    REAL, PARAMETER :: ice_frac_min=0.001
61    REAL, PARAMETER :: ice_frac_max=1. ! less than 1. if min leads fraction
62    REAL, PARAMETER :: h_ice_min=0.01*ice_den ! min ice thickness
63    REAL, PARAMETER :: h_ice_thin=0.15*ice_den ! thin ice thickness
64    ! below ice_thin, priority is melt lateral / grow height
65    ! ice_thin is also height of new ice
66    REAL, PARAMETER :: h_ice_thick=2.5*ice_den ! thin ice thickness
67    ! above ice_thick, priority is melt height / grow lateral
68    REAL, PARAMETER :: h_ice_new=1.*ice_den ! max height of new open ocean ice
69    REAL, PARAMETER :: h_ice_max=10.*ice_den ! max ice height
70
71! albedo  and radiation parameters
72    REAL, PARAMETER :: alb_sno_min=0.55 !min snow albedo
73    REAL, PARAMETER :: alb_sno_del=0.3  !max snow albedo = min + del
74    REAL, PARAMETER :: alb_ice_dry=0.75 !dry thick ice
75    REAL, PARAMETER :: alb_ice_wet=0.66 !melting thick ice
76    REAL, PARAMETER :: pen_frac=0.3 !fraction of penetrating shortwave (no snow)
77    REAL, PARAMETER :: pen_ext=1.5 !extinction of penetrating shortwave (m-1)
78
79!****************************************************************************************
80
81CONTAINS
82!
83!****************************************************************************************
84!
85  SUBROUTINE ocean_slab_init(dtime, pctsrf_rst)
86  !, seaice_rst etc
87
88    use IOIPSL
89
90    ! For ok_xxx vars (Ekman...)
91    INCLUDE "clesphys.h"
92
93    ! Input variables
94!****************************************************************************************
95    REAL, INTENT(IN)                         :: dtime
96! Variables read from restart file
97    REAL, DIMENSION(klon, nbsrf), INTENT(IN) :: pctsrf_rst
98
99! Local variables
100!****************************************************************************************
101    INTEGER                :: error
102    CHARACTER (len = 80)   :: abort_message
103    CHARACTER (len = 20)   :: modname = 'ocean_slab_intit'
104
105!****************************************************************************************
106! Allocate surface fraction read from restart file
107!****************************************************************************************
108    ALLOCATE(fsic(klon), stat = error)
109    IF (error /= 0) THEN
110       abort_message='Pb allocation tmp_pctsrf_slab'
111       CALL abort_physic(modname,abort_message,1)
112    ENDIF
113    fsic(:)=0.
114    WHERE (1.-zmasq(:)>EPSFRA)
115        fsic(:) = pctsrf_rst(:,is_sic)/(1.-zmasq(:))
116    END WHERE
117
118!****************************************************************************************
119! Allocate saved variables
120!****************************************************************************************
121    ALLOCATE(tslab(klon,nslay), stat=error)
122       IF (error /= 0) CALL abort_physic &
123         (modname,'pb allocation tslab', 1)
124
125    ALLOCATE(slab_bils(klon), stat = error)
126    IF (error /= 0) THEN
127       abort_message='Pb allocation slab_bils'
128       CALL abort_physic(modname,abort_message,1)
129    ENDIF
130    slab_bils(:) = 0.0   
131    ALLOCATE(bils_cum(klon), stat = error)
132    IF (error /= 0) THEN
133       abort_message='Pb allocation slab_bils_cum'
134       CALL abort_physic(modname,abort_message,1)
135    ENDIF
136    bils_cum(:) = 0.0   
137
138    IF (version_ocean=='sicINT') THEN
139        ALLOCATE(slab_bilg(klon), stat = error)
140        IF (error /= 0) THEN
141           abort_message='Pb allocation slab_bilg'
142           CALL abort_physic(modname,abort_message,1)
143        ENDIF
144        slab_bilg(:) = 0.0   
145        ALLOCATE(bilg_cum(klon), stat = error)
146        IF (error /= 0) THEN
147           abort_message='Pb allocation slab_bilg_cum'
148           CALL abort_physic(modname,abort_message,1)
149        ENDIF
150        bilg_cum(:) = 0.0   
151        ALLOCATE(tice(klon), stat = error)
152        IF (error /= 0) THEN
153           abort_message='Pb allocation slab_tice'
154           CALL abort_physic(modname,abort_message,1)
155        ENDIF
156        ALLOCATE(seaice(klon), stat = error)
157        IF (error /= 0) THEN
158           abort_message='Pb allocation slab_seaice'
159           CALL abort_physic(modname,abort_message,1)
160        ENDIF
161    END IF
162
163!****************************************************************************************
164! Define some parameters
165!****************************************************************************************
166! Layer thickness
167    ALLOCATE(slabh(nslay), stat = error)
168    IF (error /= 0) THEN
169       abort_message='Pb allocation slabh'
170       CALL abort_physic(modname,abort_message,1)
171    ENDIF
172    slabh(1)=50.
173! cyang = 1/heat capacity of top layer (rho.c.H)
174    cyang=1/(slabh(1)*4.228e+06)
175
176! cpl_pas periode de couplage avec slab (update tslab, pctsrf)
177! pour un calcul à chaque pas de temps, cpl_pas=1
178    cpl_pas = NINT(86400./dtime * 1.0) ! une fois par jour
179    CALL getin('cpl_pas',cpl_pas)
180    print *,'cpl_pas',cpl_pas
181
182 END SUBROUTINE ocean_slab_init
183!
184!****************************************************************************************
185!
186  SUBROUTINE ocean_slab_frac(itime, dtime, jour, pctsrf_chg, is_modified)
187
188    USE limit_read_mod
189
190!    INCLUDE "clesphys.h"
191
192! Arguments
193!****************************************************************************************
194    INTEGER, INTENT(IN)                        :: itime   ! numero du pas de temps courant
195    INTEGER, INTENT(IN)                        :: jour    ! jour a lire dans l'annee
196    REAL   , INTENT(IN)                        :: dtime   ! pas de temps de la physique (en s)
197    REAL, DIMENSION(klon,nbsrf), INTENT(INOUT) :: pctsrf_chg  ! sub-surface fraction
198    LOGICAL, INTENT(OUT)                       :: is_modified ! true if pctsrf is modified at this time step
199
200! Local variables
201!****************************************************************************************
202
203    IF (version_ocean == 'sicOBS'.OR. version_ocean == 'sicNO') THEN   
204       CALL limit_read_frac(itime, dtime, jour, pctsrf_chg, is_modified)
205    ELSE
206       pctsrf_chg(:,is_oce)=(1.-fsic(:))*(1.-zmasq(:))
207       pctsrf_chg(:,is_sic)=fsic(:)*(1.-zmasq(:))
208       is_modified=.TRUE.
209    END IF
210
211  END SUBROUTINE ocean_slab_frac
212!
213!****************************************************************************************
214!
215  SUBROUTINE ocean_slab_noice( &
216       itime, dtime, jour, knon, knindex, &
217       p1lay, cdragh, cdragq, cdragm, precip_rain, precip_snow, temp_air, spechum, &
218       AcoefH, AcoefQ, BcoefH, BcoefQ, &
219       AcoefU, AcoefV, BcoefU, BcoefV, &
220       ps, u1, v1, gustiness, tsurf_in, &
221       radsol, snow, &
222       qsurf, evap, fluxsens, fluxlat, flux_u1, flux_v1, &
223       tsurf_new, dflux_s, dflux_l, qflux)
224   
225    USE calcul_fluxs_mod
226
227    INCLUDE "clesphys.h"
228
229! Input arguments
230!****************************************************************************************
231    INTEGER, INTENT(IN)                  :: itime
232    INTEGER, INTENT(IN)                  :: jour
233    INTEGER, INTENT(IN)                  :: knon
234    INTEGER, DIMENSION(klon), INTENT(IN) :: knindex
235    REAL, INTENT(IN)                     :: dtime
236    REAL, DIMENSION(klon), INTENT(IN)    :: p1lay
237    REAL, DIMENSION(klon), INTENT(IN)    :: cdragh, cdragq, cdragm
238    REAL, DIMENSION(klon), INTENT(IN)    :: precip_rain, precip_snow
239    REAL, DIMENSION(klon), INTENT(IN)    :: temp_air, spechum
240    REAL, DIMENSION(klon), INTENT(IN)    :: AcoefH, AcoefQ, BcoefH, BcoefQ
241    REAL, DIMENSION(klon), INTENT(IN)    :: AcoefU, AcoefV, BcoefU, BcoefV
242    REAL, DIMENSION(klon), INTENT(IN)    :: ps
243    REAL, DIMENSION(klon), INTENT(IN)    :: u1, v1, gustiness
244    REAL, DIMENSION(klon), INTENT(IN)    :: tsurf_in
245    REAL, DIMENSION(klon), INTENT(INOUT) :: radsol
246
247! In/Output arguments
248!****************************************************************************************
249    REAL, DIMENSION(klon), INTENT(INOUT) :: snow
250   
251! Output arguments
252!****************************************************************************************
253    REAL, DIMENSION(klon), INTENT(OUT)   :: qsurf
254    REAL, DIMENSION(klon), INTENT(OUT)   :: evap, fluxsens, fluxlat
255    REAL, DIMENSION(klon), INTENT(OUT)   :: flux_u1, flux_v1
256    REAL, DIMENSION(klon), INTENT(OUT)   :: tsurf_new
257    REAL, DIMENSION(klon), INTENT(OUT)   :: dflux_s, dflux_l     
258    REAL, DIMENSION(klon), INTENT(OUT)   :: qflux
259
260! Local variables
261!****************************************************************************************
262    INTEGER               :: i,ki
263    ! surface fluxes
264    REAL, DIMENSION(klon) :: cal, beta, dif_grnd
265    ! flux correction
266    REAL, DIMENSION(klon) :: diff_sst, diff_siv, lmt_bils
267    ! surface wind stress
268    REAL, DIMENSION(klon) :: u0, v0
269    REAL, DIMENSION(klon) :: u1_lay, v1_lay
270    ! ice creation
271    REAL                  :: e_freeze, h_new, dfsic
272
273!****************************************************************************************
274! 1) Flux calculation
275!
276!****************************************************************************************
277    cal(:)      = 0.
278    beta(:)     = 1.
279    dif_grnd(:) = 0.
280   
281! Suppose zero surface speed
282    u0(:)=0.0
283    v0(:)=0.0
284    u1_lay(:) = u1(:) - u0(:)
285    v1_lay(:) = v1(:) - v0(:)
286
287    CALL calcul_fluxs(knon, is_oce, dtime, &
288         tsurf_in, p1lay, cal, beta, cdragh, cdragq, ps, &
289         precip_rain, precip_snow, snow, qsurf,  &
290         radsol, dif_grnd, temp_air, spechum, u1_lay, v1_lay, gustiness, &
291         f_qsat_oce,AcoefH, AcoefQ, BcoefH, BcoefQ, &
292         tsurf_new, evap, fluxlat, fluxsens, dflux_s, dflux_l)
293
294! - Flux calculation at first modele level for U and V
295    CALL calcul_flux_wind(knon, dtime, &
296         u0, v0, u1, v1, gustiness, cdragm, &
297         AcoefU, AcoefV, BcoefU, BcoefV, &
298         p1lay, temp_air, &
299         flux_u1, flux_v1) 
300
301! Accumulate total fluxes locally
302    slab_bils(:)=0.
303    DO i=1,knon
304        ki=knindex(i)
305        slab_bils(ki)=(1.-fsic(ki))*(fluxlat(i)+fluxsens(i)+radsol(i) &
306                      -precip_snow(i)*ice_lat*(1.+snow_wfact*fsic(ki)))
307        bils_cum(ki)=bils_cum(ki)+slab_bils(ki)
308! Also taux, tauy, saved vars...
309    END DO
310
311!****************************************************************************************
312! 2) Get global variables lmt_bils and diff_sst from file limit_slab.nc
313!
314!****************************************************************************************
315    lmt_bils(:)=0.
316    CALL limit_slab(itime, dtime, jour, lmt_bils, diff_sst, diff_siv) ! global pour un processus
317    ! lmt_bils and diff_sst,siv saved by limit_slab
318    qflux(:)=lmt_bils(:)+diff_sst(:)/cyang/86400.-diff_siv(:)*ice_den*ice_lat/86400.
319    ! qflux = total QFlux correction (in W/m2)
320
321!****************************************************************************************
322! 3) Recalculate new temperature
323!
324!***********************************************o*****************************************
325    tsurf_new=tsurf_in
326    IF (MOD(itime,cpl_pas).EQ.0) THEN ! time to update tslab & fraction
327        ! Compute transport
328        ! Add read QFlux and SST tendency
329        tslab(:,1)=tslab(:,1)+qflux(:)*cyang*dtime*cpl_pas
330        ! Add cumulated surface fluxes
331        tslab(:,1)=tslab(:,1)+bils_cum(:)*cyang*dtime
332        ! Update surface temperature
333        SELECT CASE(version_ocean)
334        CASE('sicNO')
335            DO i=1,knon
336                ki=knindex(i)
337                tsurf_new(i)=tslab(ki,1)
338            END DO
339        CASE('sicOBS') ! check for sea ice or tslab below freezing
340            DO i=1,knon
341                ki=knindex(i)
342                IF ((tslab(ki,1).LT.t_freeze).OR.(fsic(ki).GT.epsfra)) THEN
343                    tslab(ki,1)=t_freeze
344                END IF
345                tsurf_new(i)=tslab(ki,1)
346            END DO
347        CASE('sicINT')
348            DO i=1,knon
349                ki=knindex(i)
350                IF (fsic(ki).LT.epsfra) THEN ! Free of ice
351                    IF (tslab(ki,1).LT.t_freeze) THEN ! create new ice
352                        ! quantity of new ice formed
353                        e_freeze=(t_freeze-tslab(ki,1))/cyang/ice_lat
354                        ! new ice
355                        tice(ki)=t_freeze
356                        fsic(ki)=MIN(ice_frac_max,e_freeze/h_ice_thin)
357                        IF (fsic(ki).GT.ice_frac_min) THEN
358                            seaice(ki)=MIN(e_freeze/fsic(ki),h_ice_max)
359                            tslab(ki,1)=t_freeze
360                        ELSE
361                            fsic(ki)=0.
362                        END IF
363                        tsurf_new(i)=t_freeze
364                    ELSE
365                        tsurf_new(i)=tslab(ki,1)
366                    END IF
367                ELSE ! ice present
368                    tsurf_new(i)=t_freeze
369                    IF (tslab(ki,1).LT.t_freeze) THEN ! create new ice
370                        ! quantity of new ice formed over open ocean
371                        e_freeze=(t_freeze-tslab(ki,1))/cyang*(1.-fsic(ki)) &
372                                 /(ice_lat+ice_cap/2.*(t_freeze-tice(ki)))
373                        ! new ice height and fraction
374                        h_new=MIN(h_ice_new,seaice(ki)) ! max new height ice_new
375                        dfsic=MIN(ice_frac_max-fsic(ki),e_freeze/h_new)
376                        h_new=MIN(e_freeze/dfsic,h_ice_max)
377                        ! update tslab to freezing over open ocean only
378                        tslab(ki,1)=tslab(ki,1)*fsic(ki)+t_freeze*(1.-fsic(ki))
379                        ! update sea ice
380                        seaice(ki)=(h_new*dfsic+seaice(ki)*fsic(ki)) &
381                                   /(dfsic+fsic(ki))
382                        fsic(ki)=fsic(ki)+dfsic
383                        ! update snow?
384                    END IF !freezing
385                END IF ! sea ice present
386            END DO
387        END SELECT
388        bils_cum(:)=0.0! clear cumulated fluxes
389    END IF ! coupling time
390  END SUBROUTINE ocean_slab_noice
391!
392!****************************************************************************************
393
394  SUBROUTINE ocean_slab_ice(   &
395       itime, dtime, jour, knon, knindex, &
396       tsurf_in, p1lay, cdragh, cdragm, precip_rain, precip_snow, temp_air, spechum, &
397       AcoefH, AcoefQ, BcoefH, BcoefQ, &
398       AcoefU, AcoefV, BcoefU, BcoefV, &
399       ps, u1, v1, gustiness, &
400       radsol, snow, qsurf, qsol, agesno, &
401       alb1_new, alb2_new, evap, fluxsens, fluxlat, flux_u1, flux_v1, &
402       tsurf_new, dflux_s, dflux_l, swnet)
403
404   USE calcul_fluxs_mod
405
406   INCLUDE "YOMCST.h"
407   INCLUDE "clesphys.h"
408
409! Input arguments
410!****************************************************************************************
411    INTEGER, INTENT(IN)                  :: itime, jour, knon
412    INTEGER, DIMENSION(klon), INTENT(IN) :: knindex
413    REAL, INTENT(IN)                     :: dtime
414    REAL, DIMENSION(klon), INTENT(IN)    :: tsurf_in
415    REAL, DIMENSION(klon), INTENT(IN)    :: p1lay
416    REAL, DIMENSION(klon), INTENT(IN)    :: cdragh, cdragm
417    REAL, DIMENSION(klon), INTENT(IN)    :: precip_rain, precip_snow
418    REAL, DIMENSION(klon), INTENT(IN)    :: temp_air, spechum
419    REAL, DIMENSION(klon), INTENT(IN)    :: AcoefH, AcoefQ, BcoefH, BcoefQ
420    REAL, DIMENSION(klon), INTENT(IN)    :: AcoefU, AcoefV, BcoefU, BcoefV
421    REAL, DIMENSION(klon), INTENT(IN)    :: ps
422    REAL, DIMENSION(klon), INTENT(IN)    :: u1, v1, gustiness
423    REAL, DIMENSION(klon), INTENT(IN)    :: swnet
424
425! In/Output arguments
426!****************************************************************************************
427    REAL, DIMENSION(klon), INTENT(INOUT)          :: snow, qsol
428    REAL, DIMENSION(klon), INTENT(INOUT)          :: agesno
429    REAL, DIMENSION(klon), INTENT(INOUT)          :: radsol
430
431! Output arguments
432!****************************************************************************************
433    REAL, DIMENSION(klon), INTENT(OUT)            :: qsurf
434    REAL, DIMENSION(klon), INTENT(OUT)            :: alb1_new  ! new albedo in visible SW interval
435    REAL, DIMENSION(klon), INTENT(OUT)            :: alb2_new  ! new albedo in near IR interval
436    REAL, DIMENSION(klon), INTENT(OUT)            :: evap, fluxsens, fluxlat
437    REAL, DIMENSION(klon), INTENT(OUT)            :: flux_u1, flux_v1
438    REAL, DIMENSION(klon), INTENT(OUT)            :: tsurf_new
439    REAL, DIMENSION(klon), INTENT(OUT)            :: dflux_s, dflux_l
440
441! Local variables
442!****************************************************************************************
443    INTEGER               :: i,ki
444    REAL, DIMENSION(klon) :: cal, beta, dif_grnd
445    REAL, DIMENSION(klon) :: u0, v0
446    REAL, DIMENSION(klon) :: u1_lay, v1_lay
447    ! intermediate heat fluxes:
448    REAL                  :: f_cond, f_swpen
449    ! for snow/ice albedo:
450    REAL                  :: alb_snow, alb_ice, alb_pond
451    REAL                  :: frac_snow, frac_ice, frac_pond
452    ! for ice melt / freeze
453    REAL                  :: e_melt, snow_evap, h_test
454    ! dhsic, dfsic change in ice mass, fraction.
455    REAL                  :: dhsic, dfsic, frac_mf
456
457!****************************************************************************************
458! 1) Flux calculation
459!****************************************************************************************
460! Suppose zero surface speed
461    u0(:)=0.0
462    v0(:)=0.0
463    u1_lay(:) = u1(:) - u0(:)
464    v1_lay(:) = v1(:) - v0(:)
465
466! set beta, cal, compute conduction fluxes inside ice/snow
467    slab_bilg(:)=0.
468    dif_grnd(:)=0.
469    beta(:) = 1.
470    DO i=1,knon
471    ki=knindex(i)
472        IF (snow(i).GT.snow_min) THEN
473            ! snow-layer heat capacity
474            cal(i)=2.*RCPD/(snow(i)*ice_cap)
475            ! snow conductive flux
476            f_cond=sno_cond*(tice(ki)-tsurf_in(i))/snow(i)
477            ! all shortwave flux absorbed
478            f_swpen=0.
479            ! bottom flux (ice conduction)
480            slab_bilg(ki)=ice_cond*(tice(ki)-t_freeze)/seaice(ki)
481            ! update ice temperature
482            tice(ki)=tice(ki)-2./ice_cap/(snow(i)+seaice(ki)) &
483                     *(slab_bilg(ki)+f_cond)*dtime
484       ELSE ! bare ice
485            ! ice-layer heat capacity
486            cal(i)=2.*RCPD/(seaice(ki)*ice_cap)
487            ! conductive flux
488            f_cond=ice_cond*(t_freeze-tice(ki))/seaice(ki)
489            ! penetrative shortwave flux...
490            f_swpen=swnet(i)*pen_frac*exp(-pen_ext*seaice(ki)/ice_den)
491            slab_bilg(ki)=f_swpen-f_cond
492        END IF
493        radsol(i)=radsol(i)+f_cond-f_swpen
494    END DO
495    ! weight fluxes to ocean by sea ice fraction
496    slab_bilg(:)=slab_bilg(:)*fsic(:)
497
498! calcul_fluxs (sens, lat etc)
499    CALL calcul_fluxs(knon, is_sic, dtime, &
500        tsurf_in, p1lay, cal, beta, cdragh, cdragh, ps, &
501        precip_rain, precip_snow, snow, qsurf,  &
502        radsol, dif_grnd, temp_air, spechum, u1_lay, v1_lay, gustiness, &
503        f_qsat_oce,AcoefH, AcoefQ, BcoefH, BcoefQ, &
504        tsurf_new, evap, fluxlat, fluxsens, dflux_s, dflux_l)
505    DO i=1,knon
506        IF (snow(i).LT.snow_min) tice(knindex(i))=tsurf_new(i)
507    END DO
508
509! calcul_flux_wind
510    CALL calcul_flux_wind(knon, dtime, &
511         u0, v0, u1, v1, gustiness, cdragm, &
512         AcoefU, AcoefV, BcoefU, BcoefV, &
513         p1lay, temp_air, &
514         flux_u1, flux_v1)
515
516!****************************************************************************************
517! 2) Update snow and ice surface
518!****************************************************************************************
519! snow precip
520    DO i=1,knon
521        ki=knindex(i)
522        IF (precip_snow(i) > 0.) THEN
523            snow(i) = snow(i)+precip_snow(i)*dtime*(1.-snow_wfact*(1.-fsic(ki)))
524        END IF
525! snow and ice sublimation
526        IF (evap(i) > 0.) THEN
527           snow_evap = MIN (snow(i) / dtime, evap(i))
528           snow(i) = snow(i) - snow_evap * dtime
529           snow(i) = MAX(0.0, snow(i))
530           seaice(ki) = MAX(0.0,seaice(ki)-(evap(i)-snow_evap)*dtime)
531        ENDIF
532! Melt / Freeze from above if Tsurf>0
533        IF (tsurf_new(i).GT.t_melt) THEN
534            ! energy available for melting snow (in kg/m2 of snow)
535            e_melt = MIN(MAX(snow(i)*(tsurf_new(i)-t_melt)*ice_cap/2. &
536               /(ice_lat+ice_cap/2.*(t_melt-tice(ki))),0.0),snow(i))
537            ! remove snow
538            IF (snow(i).GT.e_melt) THEN
539                snow(i)=snow(i)-e_melt
540                tsurf_new(i)=t_melt
541            ELSE ! all snow is melted
542                ! add remaining heat flux to ice
543                e_melt=e_melt-snow(i)
544                tice(ki)=tice(ki)+e_melt*ice_lat*2./(ice_cap*seaice(ki))
545                tsurf_new(i)=tice(ki)
546            END IF
547        END IF
548! melt ice from above if Tice>0
549        IF (tice(ki).GT.t_melt) THEN
550            ! quantity of ice melted (kg/m2)
551            e_melt=MAX(seaice(ki)*(tice(ki)-t_melt)*ice_cap/2. &
552             /(ice_lat+ice_cap/2.*(t_melt-t_freeze)),0.0)
553            ! melt from above, height only
554            dhsic=MIN(seaice(ki)-h_ice_min,e_melt)
555            e_melt=e_melt-dhsic
556            IF (e_melt.GT.0) THEN
557            ! lateral melt if ice too thin
558            dfsic=MAX(fsic(ki)-ice_frac_min,e_melt/h_ice_min*fsic(ki))
559            ! if all melted add remaining heat to ocean
560            e_melt=MAX(0.,e_melt*fsic(ki)-dfsic*h_ice_min)
561            slab_bilg(ki)=slab_bilg(ki)+ e_melt*ice_lat/dtime
562            ! update height and fraction
563            fsic(ki)=fsic(ki)-dfsic
564            END IF
565            seaice(ki)=seaice(ki)-dhsic
566            ! surface temperature at melting point
567            tice(ki)=t_melt
568            tsurf_new(i)=t_melt
569        END IF
570        ! convert snow to ice if below floating line
571        h_test=(seaice(ki)+snow(i))*ice_den-seaice(ki)*sea_den
572        IF (h_test.GT.0.) THEN !snow under water
573            ! extra snow converted to ice (with added frozen sea water)
574            dhsic=h_test/(sea_den-ice_den+sno_den)
575            seaice(ki)=seaice(ki)+dhsic
576            snow(i)=snow(i)-dhsic*sno_den/ice_den
577            ! available energy (freeze sea water + bring to tice)
578            e_melt=dhsic*(1.-sno_den/ice_den)*(ice_lat+ &
579                   ice_cap/2.*(t_freeze-tice(ki)))
580            ! update ice temperature
581            tice(ki)=tice(ki)+2.*e_melt/ice_cap/(snow(i)+seaice(ki))
582        END IF
583    END DO
584
585! New albedo
586    DO i=1,knon
587        ki=knindex(i)
588       ! snow albedo: update snow age
589        IF (snow(i).GT.0.0001) THEN
590             agesno(i)=(agesno(i) + (1.-agesno(i)/50.)*dtime/86400.)&
591                         * EXP(-1.*MAX(0.0,precip_snow(i))*dtime/5.)
592        ELSE
593            agesno(i)=0.0
594        END IF
595        ! snow albedo
596        alb_snow=alb_sno_min+alb_sno_del*EXP(-agesno(i)/50.)
597        ! ice albedo (varies with ice tkickness and temp)
598        alb_ice=MAX(0.0,0.13*LOG(100.*seaice(ki)/ice_den)+0.1)
599        IF (tice(ki).GT.t_freeze-0.01) THEN
600            alb_ice=MIN(alb_ice,alb_ice_wet)
601        ELSE
602            alb_ice=MIN(alb_ice,alb_ice_dry)
603        END IF
604        ! pond albedo
605        alb_pond=0.36-0.1*(2.0+MIN(0.0,MAX(tice(ki)-t_melt,-2.0)))
606        ! pond fraction
607        frac_pond=0.2*(2.0+MIN(0.0,MAX(tice(ki)-t_melt,-2.0)))
608        ! snow fraction
609        frac_snow=MAX(0.0,MIN(1.0-frac_pond,snow(i)/snow_min))
610        ! ice fraction
611        frac_ice=MAX(0.0,1.-frac_pond-frac_snow)
612        ! total albedo
613        alb1_new(i)=alb_snow*frac_snow+alb_ice*frac_ice+alb_pond*frac_pond
614    END DO
615    alb2_new(:) = alb1_new(:)
616
617!****************************************************************************************
618! 3) Recalculate new ocean temperature (add fluxes below ice)
619!    Melt / freeze from below
620!***********************************************o*****************************************
621    !cumul fluxes
622    bilg_cum(:)=bilg_cum(:)+slab_bilg(:)
623    IF (MOD(itime,cpl_pas).EQ.0) THEN ! time to update tslab & fraction
624        ! Add cumulated surface fluxes
625        tslab(:,1)=tslab(:,1)+bilg_cum(:)*cyang*dtime
626        DO i=1,knon
627            ki=knindex(i)
628            ! split lateral/top melt-freeze
629            frac_mf=MIN(1.,MAX(0.,(seaice(ki)-h_ice_thin)/(h_ice_thick-h_ice_thin)))
630            IF (tslab(ki,1).LE.t_freeze) THEN
631               ! ****** Form new ice from below *******
632               ! quantity of new ice
633                e_melt=(t_freeze-tslab(ki,1))/cyang &
634                       /(ice_lat+ice_cap/2.*(t_freeze-tice(ki)))
635               ! first increase height to h_thin
636               dhsic=MAX(0.,MIN(h_ice_thin-seaice(ki),e_melt/fsic(ki)))
637               seaice(ki)=dhsic+seaice(ki)
638               e_melt=e_melt-fsic(ki)*dhsic
639               IF (e_melt.GT.0.) THEN
640               ! frac_mf fraction used for lateral increase
641               dfsic=MIN(ice_frac_max-fsic(ki),e_melt*frac_mf/seaice(ki))
642               fsic(ki)=fsic(ki)+dfsic
643               e_melt=e_melt-dfsic*seaice(ki)
644               ! rest used to increase height
645               seaice(ki)=MIN(h_ice_max,seaice(ki)+e_melt/fsic(ki))
646               END IF
647               tslab(ki,1)=t_freeze
648           ELSE ! slab temperature above freezing
649               ! ****** melt ice from below *******
650               ! quantity of melted ice
651               e_melt=(tslab(ki,1)-t_freeze)/cyang &
652                       /(ice_lat+ice_cap/2.*(tice(ki)-t_freeze))
653               ! first decrease height to h_thick
654               dhsic=MAX(0.,MIN(seaice(ki)-h_ice_thick,e_melt/fsic(ki)))
655               seaice(ki)=seaice(ki)-dhsic
656               e_melt=e_melt-fsic(ki)*dhsic
657               IF (e_melt.GT.0) THEN
658               ! frac_mf fraction used for height decrease
659               dhsic=MAX(0.,MIN(seaice(ki)-h_ice_min,e_melt*frac_mf/fsic(ki)))
660               seaice(ki)=seaice(ki)-dhsic
661               e_melt=e_melt-fsic(ki)*dhsic
662               ! rest used to decrease fraction (up to 0!)
663               dfsic=MIN(fsic(ki),e_melt/seaice(ki))
664               ! keep remaining in ocean
665               e_melt=e_melt-dfsic*seaice(ki)
666               END IF
667               tslab(ki,1)=t_freeze+e_melt*ice_lat*cyang
668               fsic(ki)=fsic(ki)-dfsic
669           END IF
670        END DO
671        bilg_cum(:)=0.
672    END IF ! coupling time
673   
674    !tests fraction glace
675    WHERE (fsic.LT.ice_frac_min)
676        tslab(:,1)=tslab(:,1)-fsic*seaice*ice_lat*cyang
677        tice=t_melt
678        fsic=0.
679        seaice=0.
680    END WHERE
681
682  END SUBROUTINE ocean_slab_ice
683!
684!****************************************************************************************
685!
686  SUBROUTINE ocean_slab_final
687
688!****************************************************************************************
689! Deallocate module variables
690!****************************************************************************************
691    IF (ALLOCATED(tslab)) DEALLOCATE(tslab)
692    IF (ALLOCATED(fsic)) DEALLOCATE(fsic)
693    IF (ALLOCATED(slab_bils)) DEALLOCATE(slab_bils)
694    IF (ALLOCATED(slab_bilg)) DEALLOCATE(slab_bilg)
695    IF (ALLOCATED(bilg_cum)) DEALLOCATE(bilg_cum)
696    IF (ALLOCATED(bils_cum)) DEALLOCATE(bils_cum)
697    IF (ALLOCATED(tslab)) DEALLOCATE(tslab)
698
699  END SUBROUTINE ocean_slab_final
700
701END MODULE ocean_slab_mod
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