Newer
Older
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
MODULE zdfdrg
!!======================================================================
!! *** MODULE zdfdrg ***
!! Ocean physics: top and/or Bottom friction
!!======================================================================
!! History : OPA ! 1997-06 (G. Madec, A.-M. Treguier) Original code
!! NEMO 1.0 ! 2002-06 (G. Madec) F90: Free form and module
!! 3.2 ! 2009-09 (A.C.Coward) Correction to include barotropic contribution
!! 3.3 ! 2010-10 (C. Ethe, G. Madec) reorganisation of initialisation phase
!! 3.4 ! 2011-11 (H. Liu) implementation of semi-implicit bottom friction option
!! ! 2012-06 (H. Liu) implementation of Log Layer bottom friction option
!! 4.0 ! 2017-05 (G. Madec) zdfbfr becomes zdfdrg + variable names change
!! + drag defined at t-point + new user interface + top drag (ocean cavities)
!!----------------------------------------------------------------------
!!----------------------------------------------------------------------
!! zdf_drg : update bottom friction coefficient (non-linear bottom friction only)
!! zdf_drg_exp : compute the top & bottom friction in explicit case
!! zdf_drg_init : read in namdrg namelist and control the bottom friction parameters.
!! drg_init :
!!----------------------------------------------------------------------
USE oce ! ocean dynamics and tracers variables
USE phycst , ONLY : vkarmn
USE dom_oce ! ocean space and time domain variables
USE zdf_oce ! ocean vertical physics variables
USE trd_oce ! trends: ocean variables
USE trddyn ! trend manager: dynamics
!
USE in_out_manager ! I/O manager
USE iom ! I/O module
USE lbclnk ! ocean lateral boundary conditions (or mpp link)
USE lib_mpp ! distributed memory computing
USE prtctl ! Print control
USE sbc_oce , ONLY : nn_ice
IMPLICIT NONE
PRIVATE
PUBLIC zdf_drg ! called by zdf_phy
PUBLIC zdf_drg_exp ! called by dyn_zdf
PUBLIC zdf_drg_init ! called by zdf_phy_init
! !!* Namelist namdrg: nature of drag coefficient namelist *
LOGICAL , PUBLIC :: ln_drg_OFF ! free-slip : Cd = 0
LOGICAL :: ln_lin ! linear drag: Cd = Cd0_lin
LOGICAL :: ln_non_lin ! non-linear drag: Cd = Cd0_nl |U|
LOGICAL :: ln_loglayer ! logarithmic drag: Cd = vkarmn/log(z/z0)
LOGICAL , PUBLIC :: ln_drgimp ! implicit top/bottom friction flag
LOGICAL , PUBLIC :: ln_drgice_imp ! implicit ice-ocean drag
! !!* Namelist namdrg_top & _bot: TOP or BOTTOM coefficient namelist *
REAL(wp) :: rn_Cd0 !: drag coefficient [ - ]
REAL(wp) :: rn_Uc0 !: characteristic velocity (linear case: tau=rho*Cd0*Uc0*u) [m/s]
REAL(wp) :: rn_Cdmax !: drag value maximum (ln_loglayer=T) [ - ]
REAL(wp) :: rn_z0 !: roughness (ln_loglayer=T) [ m ]
REAL(wp) :: rn_ke0 !: background kinetic energy (non-linear case) [m2/s2]
LOGICAL :: ln_boost !: =T regional boost of Cd0 ; =F Cd0 horizontally uniform
REAL(wp) :: rn_boost !: local boost factor [ - ]
REAL(wp), PUBLIC :: r_Cdmin_top, r_Cdmax_top, r_z0_top, r_ke0_top ! set from namdrg_top namelist values
REAL(wp), PUBLIC :: r_Cdmin_bot, r_Cdmax_bot, r_z0_bot, r_ke0_bot ! - - namdrg_bot - -
INTEGER :: ndrg ! choice of the type of drag coefficient
! ! associated indices:
INTEGER, PARAMETER :: np_OFF = 0 ! free-slip: drag set to zero
INTEGER, PARAMETER :: np_lin = 1 ! linear drag: Cd = Cd0_lin
INTEGER, PARAMETER :: np_non_lin = 2 ! non-linear drag: Cd = Cd0_nl |U|
INTEGER, PARAMETER :: np_loglayer = 3 ! non linear drag (logarithmic formulation): Cd = vkarmn/log(z/z0)
LOGICAL , PUBLIC :: l_zdfdrg !: flag to update at each time step the top/bottom Cd
LOGICAL :: l_log_not_linssh !: flag to update at each time step the position ot the velocity point
!
REAL(wp), ALLOCATABLE, SAVE, DIMENSION(:,:), PUBLIC :: rCd0_top, rCd0_bot !: precomputed top/bottom drag coeff. at t-point (>0)
REAL(wp), ALLOCATABLE, SAVE, DIMENSION(:,:), PUBLIC :: rCdU_top, rCdU_bot !: top/bottom drag coeff. at t-point (<0) [m/s]
!! * Substitutions
# include "do_loop_substitute.h90"
sparonuz
committed
# include "single_precision_substitute.h90"
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
# include "domzgr_substitute.h90"
!!----------------------------------------------------------------------
!! NEMO/OCE 4.0 , NEMO Consortium (2018)
!! $Id: zdfdrg.F90 14834 2021-05-11 09:24:44Z hadcv $
!! Software governed by the CeCILL license (see ./LICENSE)
!!----------------------------------------------------------------------
CONTAINS
SUBROUTINE zdf_drg( kt, Kmm, k_mk, pCdmin, pCdmax, pz0, pke0, pCd0, & ! <<== in
& pCdU ) ! ==>> out : bottom drag [m/s]
!!----------------------------------------------------------------------
!! *** ROUTINE zdf_drg ***
!!
!! ** Purpose : update the top/bottom drag coefficient (non-linear case only)
!!
!! ** Method : In non linear friction case, the drag coeficient is
!! a function of the velocity:
!! Cd = cd0 * |U+Ut|
!! where U is the top or bottom velocity and
!! Ut a tidal velocity (Ut^2 = Tidal kinetic energy
!! assumed here here to be constant)
!! Depending on the input variable, the top- or bottom drag is compted
!!
!! ** Action : p_Cd drag coefficient at t-point
!!----------------------------------------------------------------------
INTEGER , INTENT(in ) :: kt ! ocean time-step index
INTEGER , INTENT(in ) :: Kmm ! ocean time level index
! ! !! !== top or bottom variables ==!
INTEGER , DIMENSION(:,:), INTENT(in ) :: k_mk ! wet level (1st or last)
REAL(wp) , INTENT(in ) :: pCdmin ! min drag value
REAL(wp) , INTENT(in ) :: pCdmax ! max drag value
REAL(wp) , INTENT(in ) :: pz0 ! roughness
REAL(wp) , INTENT(in ) :: pke0 ! background tidal KE
REAL(wp), DIMENSION(:,:), INTENT(in ) :: pCd0 ! masked precomputed part of Cd0
REAL(wp), DIMENSION(:,:), INTENT( out) :: pCdU ! = - Cd*|U| (t-points) [m/s]
!!
INTEGER :: ji, jj ! dummy loop indices
INTEGER :: imk ! local integers
REAL(wp):: zzz, zut, zvt, zcd ! local scalars
!!----------------------------------------------------------------------
!
IF( l_log_not_linssh ) THEN !== "log layer" ==! compute Cd and -Cd*|U|
DO_2D_OVR( nn_hls-1, nn_hls-1, nn_hls-1, nn_hls-1 )
imk = k_mk(ji,jj) ! ocean bottom level at t-points
zut = uu(ji,jj,imk,Kmm) + uu(ji-1,jj,imk,Kmm) ! 2 x velocity at t-point
zvt = vv(ji,jj,imk,Kmm) + vv(ji,jj-1,imk,Kmm)
zzz = 0.5_wp * e3t(ji,jj,imk,Kmm) ! altitude below/above (top/bottom) the boundary
!
!!JC: possible WAD implementation should modify line below if layers vanish
zcd = ( vkarmn / LOG( zzz / pz0 ) )**2
zcd = pCd0(ji,jj) * MIN( MAX( pCdmin , zcd ) , pCdmax ) ! here pCd0 = mask*boost
pCdU(ji,jj) = - zcd * SQRT( 0.25 * ( zut*zut + zvt*zvt ) + pke0 )
END_2D
ELSE !== standard Cd ==!
DO_2D_OVR( nn_hls-1, nn_hls-1, nn_hls-1, nn_hls-1 )
imk = k_mk(ji,jj) ! ocean bottom level at t-points
zut = uu(ji,jj,imk,Kmm) + uu(ji-1,jj,imk,Kmm) ! 2 x velocity at t-point
zvt = vv(ji,jj,imk,Kmm) + vv(ji,jj-1,imk,Kmm)
! ! here pCd0 = mask*boost * drag
pCdU(ji,jj) = - pCd0(ji,jj) * SQRT( 0.25 * ( zut*zut + zvt*zvt ) + pke0 )
END_2D
ENDIF
!
sparonuz
committed
IF(sn_cfctl%l_prtctl) CALL prt_ctl( tab2d_1=CASTDP(pCdU), clinfo1=' Cd*U ')
!
END SUBROUTINE zdf_drg
SUBROUTINE zdf_drg_exp( kt, Kmm, pub, pvb, pua, pva )
!!----------------------------------------------------------------------
!! *** ROUTINE zdf_drg_exp ***
!!
!! ** Purpose : compute and add the explicit top and bottom frictions.
!!
!! ** Method : in explicit case,
!!
!! NB: in implicit case the calculation is performed in dynzdf.F90
!!
!! ** Action : (pua,pva) momentum trend increased by top & bottom friction trend
!!---------------------------------------------------------------------
INTEGER , INTENT(in ) :: kt ! ocean time-step index
INTEGER , INTENT(in ) :: Kmm ! time level indices
sparonuz
committed
REAL(dp), DIMENSION(jpi,jpj,jpk), INTENT(inout) :: pub, pvb ! the two components of the before velocity
REAL(dp), DIMENSION(jpi,jpj,jpk), INTENT(inout) :: pua, pva ! the two components of the velocity tendency
!!
INTEGER :: ji, jj ! dummy loop indexes
INTEGER :: ikbu, ikbv ! local integers
REAL(wp) :: zm1_2dt ! local scalar
REAL(wp) :: zCdu, zCdv ! - -
sparonuz
committed
REAL(dp), DIMENSION(:,:,:), ALLOCATABLE :: ztrdu, ztrdv
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
!!---------------------------------------------------------------------
!
!!gm bug : time step is only rn_Dt (not 2 rn_Dt if euler start !)
zm1_2dt = - 1._wp / ( 2._wp * rn_Dt )
IF( l_trddyn ) THEN ! trends: store the input trends
ALLOCATE( ztrdu(jpi,jpj,jpk) , ztrdv(jpi,jpj,jpk) )
ztrdu(:,:,:) = pua(:,:,:)
ztrdv(:,:,:) = pva(:,:,:)
ENDIF
DO_2D( 0, 0, 0, 0 )
ikbu = mbku(ji,jj) ! deepest wet ocean u- & v-levels
ikbv = mbkv(ji,jj)
!
! Apply stability criteria on absolute value : abs(bfr/e3) < 1/(2dt) => bfr/e3 > -1/(2dt)
zCdu = 0.5*( rCdU_bot(ji+1,jj)+rCdU_bot(ji,jj) ) / e3u(ji,jj,ikbu,Kmm)
zCdv = 0.5*( rCdU_bot(ji,jj+1)+rCdU_bot(ji,jj) ) / e3v(ji,jj,ikbv,Kmm)
!
pua(ji,jj,ikbu) = pua(ji,jj,ikbu) + MAX( zCdu , zm1_2dt ) * pub(ji,jj,ikbu)
pva(ji,jj,ikbv) = pva(ji,jj,ikbv) + MAX( zCdv , zm1_2dt ) * pvb(ji,jj,ikbv)
END_2D
!
IF( ln_isfcav ) THEN ! ocean cavities
DO_2D( 0, 0, 0, 0 )
ikbu = miku(ji,jj) ! first wet ocean u- & v-levels
ikbv = mikv(ji,jj)
!
! Apply stability criteria on absolute value : abs(bfr/e3) < 1/(2dt) => bfr/e3 > -1/(2dt)
zCdu = 0.5*( rCdU_top(ji+1,jj)+rCdU_top(ji,jj) ) / e3u(ji,jj,ikbu,Kmm) ! NB: Cdtop masked
zCdv = 0.5*( rCdU_top(ji,jj+1)+rCdU_top(ji,jj) ) / e3v(ji,jj,ikbv,Kmm)
!
pua(ji,jj,ikbu) = pua(ji,jj,ikbu) + MAX( zCdu , zm1_2dt ) * pub(ji,jj,ikbu)
pva(ji,jj,ikbv) = pva(ji,jj,ikbv) + MAX( zCdv , zm1_2dt ) * pvb(ji,jj,ikbv)
END_2D
ENDIF
!
IF( l_trddyn ) THEN ! trends: send trends to trddyn for further diagnostics
ztrdu(:,:,:) = pua(:,:,:) - ztrdu(:,:,:)
ztrdv(:,:,:) = pva(:,:,:) - ztrdv(:,:,:)
CALL trd_dyn( ztrdu(:,:,:), ztrdv(:,:,:), jpdyn_bfr, kt, Kmm )
DEALLOCATE( ztrdu, ztrdv )
ENDIF
! ! print mean trends (used for debugging)
IF(sn_cfctl%l_prtctl) CALL prt_ctl( tab3d_1=pua, clinfo1=' bfr - Ua: ', mask1=umask, &
& tab3d_2=pva, clinfo2= ' Va: ', mask2=vmask, clinfo3='dyn' )
!
END SUBROUTINE zdf_drg_exp
SUBROUTINE zdf_drg_init
!!----------------------------------------------------------------------
!! *** ROUTINE zdf_brg_init ***
!!
!! ** Purpose : Initialization of the bottom friction
!!
!! ** Method : Read the namdrg namelist and check their consistency
!! called at the first timestep (nit000)
!!----------------------------------------------------------------------
INTEGER :: ji, jj ! dummy loop indexes
INTEGER :: ios, ioptio ! local integers
!!
NAMELIST/namdrg/ ln_drg_OFF, ln_lin, ln_non_lin, ln_loglayer, ln_drgimp, ln_drgice_imp
!!----------------------------------------------------------------------
!
! !== drag nature ==!
!
READ ( numnam_ref, namdrg, IOSTAT = ios, ERR = 901)
901 IF( ios /= 0 ) CALL ctl_nam( ios , 'namdrg in reference namelist' )
READ ( numnam_cfg, namdrg, IOSTAT = ios, ERR = 902 )
902 IF( ios > 0 ) CALL ctl_nam( ios , 'namdrg in configuration namelist' )
IF(lwm) WRITE ( numond, namdrg )
!
IF ( ln_drgice_imp .AND. nn_ice /= 2 ) ln_drgice_imp = .FALSE.
!
IF(lwp) THEN
WRITE(numout,*)
WRITE(numout,*) 'zdf_drg_init : top and/or bottom drag setting'
WRITE(numout,*) '~~~~~~~~~~~~'
WRITE(numout,*) ' Namelist namdrg : top/bottom friction choices'
WRITE(numout,*) ' free-slip : Cd = 0 ln_drg_OFF = ', ln_drg_OFF
WRITE(numout,*) ' linear drag : Cd = Cd0 ln_lin = ', ln_lin
WRITE(numout,*) ' non-linear drag: Cd = Cd0_nl |U| ln_non_lin = ', ln_non_lin
WRITE(numout,*) ' logarithmic drag: Cd = vkarmn/log(z/z0) ln_loglayer = ', ln_loglayer
WRITE(numout,*) ' implicit friction ln_drgimp = ', ln_drgimp
WRITE(numout,*) ' implicit ice-ocean drag ln_drgice_imp =', ln_drgice_imp
ENDIF
!
ioptio = 0 ! set ndrg and control check
IF( ln_drg_OFF ) THEN ; ndrg = np_OFF ; ioptio = ioptio + 1 ; ENDIF
IF( ln_lin ) THEN ; ndrg = np_lin ; ioptio = ioptio + 1 ; ENDIF
IF( ln_non_lin ) THEN ; ndrg = np_non_lin ; ioptio = ioptio + 1 ; ENDIF
IF( ln_loglayer ) THEN ; ndrg = np_loglayer ; ioptio = ioptio + 1 ; ENDIF
!
IF( ioptio /= 1 ) CALL ctl_stop( 'zdf_drg_init: Choose ONE type of drag coef in namdrg' )
!
IF ( ln_drgice_imp.AND.(.NOT.ln_drgimp) ) &
& CALL ctl_stop( 'zdf_drg_init: ln_drgice_imp=T requires ln_drgimp=T' )
!
! !== BOTTOM drag setting ==! (applied at seafloor)
!
ALLOCATE( rCd0_bot(jpi,jpj), rCdU_bot(jpi,jpj) )
CALL drg_init( 'BOTTOM' , mbkt , & ! <== in
& r_Cdmin_bot, r_Cdmax_bot, r_z0_bot, r_ke0_bot, rCd0_bot, rCdU_bot ) ! ==> out
!
! !== TOP drag setting ==! (applied at the top of ocean cavities)
!
IF( ln_isfcav.OR.ln_drgice_imp ) THEN ! Ocean cavities: top friction setting
ALLOCATE( rCdU_top(jpi,jpj) )
ENDIF
!
IF( ln_isfcav ) THEN
ALLOCATE( rCd0_top(jpi,jpj))
CALL drg_init( 'TOP ' , mikt , & ! <== in
& r_Cdmin_top, r_Cdmax_top, r_z0_top, r_ke0_top, rCd0_top, rCdU_top ) ! ==> out
ENDIF
!
END SUBROUTINE zdf_drg_init
SUBROUTINE drg_init( cd_topbot, k_mk, &
& pCdmin, pCdmax, pz0, pke0, pCd0, pCdU )
!!----------------------------------------------------------------------
!! *** ROUTINE drg_init ***
!!
!! ** Purpose : Initialization of the top/bottom friction CdO and Cd
!! from namelist parameters
!!----------------------------------------------------------------------
CHARACTER(len=6) , INTENT(in ) :: cd_topbot ! top/ bot indicator
INTEGER , DIMENSION(:,:), INTENT(in ) :: k_mk ! 1st/last wet level
REAL(wp) , INTENT( out) :: pCdmin, pCdmax ! min and max drag coef. [-]
REAL(wp) , INTENT( out) :: pz0 ! roughness [m]
REAL(wp) , INTENT( out) :: pke0 ! background KE [m2/s2]
REAL(wp), DIMENSION(:,:), INTENT( out) :: pCd0 ! masked precomputed part of the non-linear drag coefficient
REAL(wp), DIMENSION(:,:), INTENT( out) :: pCdU ! minus linear drag*|U| at t-points [m/s]
!!
CHARACTER(len=40) :: cl_namdrg, cl_file, cl_varname, cl_namref, cl_namcfg ! local names
INTEGER :: ji, jj ! dummy loop indexes
LOGICAL :: ll_top, ll_bot ! local logical
INTEGER :: ios, inum, imk ! local integers
REAL(wp):: zmsk, zzz, zcd ! local scalars
REAL(wp), DIMENSION(jpi,jpj) :: zmsk_boost ! 2D workspace
!!
NAMELIST/namdrg_top/ rn_Cd0, rn_Uc0, rn_Cdmax, rn_ke0, rn_z0, ln_boost, rn_boost
NAMELIST/namdrg_bot/ rn_Cd0, rn_Uc0, rn_Cdmax, rn_ke0, rn_z0, ln_boost, rn_boost
!!----------------------------------------------------------------------
!
! !== set TOP / BOTTOM specificities ==!
ll_top = .FALSE.
ll_bot = .FALSE.
!
SELECT CASE (cd_topbot)
CASE( 'TOP ' )
ll_top = .TRUE.
cl_namdrg = 'namdrg_top'
cl_namref = 'namdrg_top in reference namelist'
cl_namcfg = 'namdrg_top in configuration namelist'
cl_file = 'tfr_coef.nc'
cl_varname = 'tfr_coef'
CASE( 'BOTTOM' )
ll_bot = .TRUE.
cl_namdrg = 'namdrg_bot'
cl_namref = 'namdrg_bot in reference namelist'
cl_namcfg = 'namdrg_bot in configuration namelist'
cl_file = 'bfr_coef.nc'
cl_varname = 'bfr_coef'
CASE DEFAULT
CALL ctl_stop( 'drg_init: bad value for cd_topbot ' )
END SELECT
!
! !== read namlist ==!
!
IF(ll_top) READ ( numnam_ref, namdrg_top, IOSTAT = ios, ERR = 901)
IF(ll_bot) READ ( numnam_ref, namdrg_bot, IOSTAT = ios, ERR = 901)
901 IF( ios /= 0 ) CALL ctl_nam( ios , TRIM(cl_namref) )
IF(ll_top) READ ( numnam_cfg, namdrg_top, IOSTAT = ios, ERR = 902 )
IF(ll_bot) READ ( numnam_cfg, namdrg_bot, IOSTAT = ios, ERR = 902 )
902 IF( ios > 0 ) CALL ctl_nam( ios , TRIM(cl_namcfg) )
IF(lwm .AND. ll_top) WRITE ( numond, namdrg_top )
IF(lwm .AND. ll_bot) WRITE ( numond, namdrg_bot )
!
IF(lwp) THEN
WRITE(numout,*)
WRITE(numout,*) ' Namelist ',TRIM(cl_namdrg),' : set ',TRIM(cd_topbot),' friction parameters'
WRITE(numout,*) ' drag coefficient rn_Cd0 = ', rn_Cd0
WRITE(numout,*) ' characteristic velocity (linear case) rn_Uc0 = ', rn_Uc0, ' m/s'
WRITE(numout,*) ' non-linear drag maximum rn_Cdmax = ', rn_Cdmax
WRITE(numout,*) ' background kinetic energy (n-l case) rn_ke0 = ', rn_ke0
WRITE(numout,*) ' bottom roughness (n-l case) rn_z0 = ', rn_z0
WRITE(numout,*) ' set a regional boost of Cd0 ln_boost = ', ln_boost
WRITE(numout,*) ' associated boost factor rn_boost = ', rn_boost
ENDIF
!
! !== return some namelist parametres ==! (used in non_lin and loglayer cases)
pCdmin = rn_Cd0
pCdmax = rn_Cdmax
pz0 = rn_z0
pke0 = rn_ke0
!
! !== mask * boost factor ==!
!
IF( ln_boost ) THEN !* regional boost: boost factor = 1 + regional boost
IF(lwp) WRITE(numout,*)
IF(lwp) WRITE(numout,*) ' ==>>> use a regional boost read in ', TRIM(cl_file), ' file'
IF(lwp) WRITE(numout,*) ' using enhancement factor of ', rn_boost
! cl_varname is a coefficient in [0,1] giving where to apply the regional boost
CALL iom_open ( TRIM(cl_file), inum )
CALL iom_get ( inum, jpdom_global, TRIM(cl_varname), zmsk_boost, 1 )
CALL iom_close( inum)
zmsk_boost(:,:) = 1._wp + rn_boost * zmsk_boost(:,:)
!
ELSE !* no boost: boost factor = 1
zmsk_boost(:,:) = 1._wp
ENDIF
! !* mask outside ocean cavities area (top) or land area (bot)
IF(ll_top) zmsk_boost(:,:) = zmsk_boost(:,:) * ssmask(:,:) * (1. - tmask(:,:,1) ) ! none zero in ocean cavities only
IF(ll_bot) zmsk_boost(:,:) = zmsk_boost(:,:) * ssmask(:,:) ! x seafloor mask
!
l_log_not_linssh = .FALSE. ! default definition
!
SELECT CASE( ndrg )
!
CASE( np_OFF ) !== No top/bottom friction ==! (pCdU = 0)
IF(lwp) WRITE(numout,*)
IF(lwp) WRITE(numout,*) ' ==>>> ',TRIM(cd_topbot),' free-slip, friction set to zero'
!
l_zdfdrg = .FALSE. ! no time variation of the drag: set it one for all
!
pCdU(:,:) = 0._wp
pCd0(:,:) = 0._wp
!
CASE( np_lin ) !== linear friction ==! (pCdU = Cd0 * Uc0)
IF(lwp) WRITE(numout,*)
IF(lwp) WRITE(numout,*) ' ==>>> linear ',TRIM(cd_topbot),' friction (constant coef = Cd0*Uc0 = ', rn_Cd0*rn_Uc0, ')'
!
l_zdfdrg = .FALSE. ! no time variation of the Cd*|U| : set it one for all
!
pCd0(:,:) = rn_Cd0 * zmsk_boost(:,:) !* constant in time drag coefficient (= mask (and boost) Cd0)
pCdU(:,:) = - pCd0(:,:) * rn_Uc0 ! using a constant velocity
!
CASE( np_non_lin ) !== non-linear friction ==! (pCd0 = Cd0 )
IF(lwp) WRITE(numout,*)
IF(lwp) WRITE(numout,*) ' ==>>> quadratic ',TRIM(cd_topbot),' friction (propotional to module of the velocity)'
IF(lwp) WRITE(numout,*) ' with a drag coefficient Cd0 = ', rn_Cd0, ', and'
IF(lwp) WRITE(numout,*) ' a background velocity module of (rn_ke0)^1/2 = ', SQRT(rn_ke0), 'm/s)'
!
l_zdfdrg = .TRUE. !* Cd*|U| updated at each time-step (it depends on ocean velocity)
!
pCd0(:,:) = rn_Cd0 * zmsk_boost(:,:) !* constant in time proportionality coefficient (= mask (and boost) Cd0)
pCdU(:,:) = 0._wp !
!
CASE( np_loglayer ) !== logarithmic layer formulation of friction ==! (CdU = (vkarman log(z/z0))^2 |U| )
IF(lwp) WRITE(numout,*)
IF(lwp) WRITE(numout,*) ' ==>>> quadratic ',TRIM(cd_topbot),' drag (propotional to module of the velocity)'
IF(lwp) WRITE(numout,*) ' with a logarithmic Cd0 formulation Cd0 = ( vkarman log(z/z0) )^2 ,'
IF(lwp) WRITE(numout,*) ' a background velocity module of (rn_ke0)^1/2 = ', SQRT(pke0), 'm/s), '
IF(lwp) WRITE(numout,*) ' a logarithmic formulation: a roughness of ', pz0, ' meters, and '
IF(lwp) WRITE(numout,*) ' a proportionality factor bounded by min/max values of ', pCdmin, pCdmax
!
l_zdfdrg = .TRUE. !* Cd*|U| updated at each time-step (it depends on ocean velocity)
!
IF( ln_linssh ) THEN !* pCd0 = (v log(z/z0))^2 as velocity points have a fixed z position
IF(lwp) WRITE(numout,*)
IF(lwp) WRITE(numout,*) ' N.B. linear free surface case, Cd0 computed one for all'
!
l_log_not_linssh = .FALSE. !- don't update Cd at each time step
!
DO_2D( nn_hls, nn_hls, nn_hls, nn_hls ) ! pCd0 = mask (and boosted) logarithmic drag coef.
zzz = 0.5_wp * e3t_0(ji,jj,k_mk(ji,jj))
zcd = ( vkarmn / LOG( zzz / rn_z0 ) )**2
pCd0(ji,jj) = zmsk_boost(ji,jj) * MIN( MAX( rn_Cd0 , zcd ) , rn_Cdmax ) ! rn_Cd0 < Cd0 < rn_Cdmax
END_2D
ELSE !* Cd updated at each time-step ==> pCd0 = mask * boost
IF(lwp) WRITE(numout,*)
IF(lwp) WRITE(numout,*) ' N.B. non-linear free surface case, Cd0 updated at each time-step '
!
l_log_not_linssh = .TRUE. ! compute the drag coef. at each time-step
!
pCd0(:,:) = zmsk_boost(:,:)
ENDIF
pCdU(:,:) = 0._wp ! initialisation to zero (will be updated at each time step)
!
CASE DEFAULT
CALL ctl_stop( 'drg_init: bad flag value for ndrg ' )
END SELECT
!
END SUBROUTINE drg_init
!!======================================================================
END MODULE zdfdrg