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
77
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
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
MODULE isfcav
!!======================================================================
!! *** MODULE isfcav ***
!! Ice shelf cavity module : update ice shelf melting under ice
!! shelf
!!======================================================================
!! History : 3.2 ! 2011-02 (C.Harris ) Original code isf cav
!! 3.4 ! 2013-03 (P. Mathiot) Merging + parametrization
!! 4.1 ! 2019-09 (P. Mathiot) Split ice shelf cavity and ice shelf parametrisation
!!----------------------------------------------------------------------
!!----------------------------------------------------------------------
!! isf_cav : update ice shelf melting under ice shelf
!!----------------------------------------------------------------------
USE isf_oce ! ice shelf public variables
!
USE isfrst , ONLY: isfrst_write, isfrst_read ! ice shelf restart read/write subroutine
USE isfutils , ONLY: debug ! ice shelf debug subroutine
USE isftbl , ONLY: isf_tbl ! ice shelf top boundary layer properties subroutine
USE isfcavmlt, ONLY: isfcav_mlt ! ice shelf melt formulation subroutine
USE isfcavgam, ONLY: isfcav_gammats ! ice shelf melt exchange coeficient subroutine
USE isfdiags , ONLY: isf_diags_flx ! ice shelf diags subroutine
!
USE oce , ONLY: ts, uu, vv, rn2 ! ocean dynamics and tracers
USE dom_oce ! ocean space and time domain
USE par_oce , ONLY: jpi,jpj ! ocean space and time domain
USE phycst , ONLY: grav,rho0,rho0_rcp,r1_rho0_rcp ! physical constants
USE eosbn2 , ONLY: ln_teos10 ! use ln_teos10 or not
!
USE in_out_manager ! I/O manager
USE iom ! I/O library
USE fldread ! read input field at current time step
USE lbclnk ! lbclnk
USE lib_mpp ! MPP library
IMPLICIT NONE
PRIVATE
PUBLIC isf_cav, isf_cav_init ! routine called in isfmlt
!! * Substitutions
# include "do_loop_substitute.h90"
# include "domzgr_substitute.h90"
!!----------------------------------------------------------------------
!! NEMO/OCE 4.0 , NEMO Consortium (2018)
!! $Id: sbcisf.F90 10536 2019-01-16 19:21:09Z mathiot $
!! Software governed by the CeCILL license (see ./LICENSE)
!!----------------------------------------------------------------------
CONTAINS
SUBROUTINE isf_cav( kt, Kmm, ptsc, pqfwf )
!!---------------------------------------------------------------------
!! *** ROUTINE isf_cav ***
!!
!! ** Purpose : handle surface boundary condition under ice shelf
!!
!! ** Method : based on Mathiot et al. (2017)
!!
!! ** Action : - compute geometry of the Losch top bournary layer (see Losch et al. 2008)
!! - depending on the chooses option
!! - compute temperature/salt in the tbl
!! - compute exchange coeficient
!! - compute heat and fwf fluxes
!! - output
!!
!! ** Convention : all fluxes are from isf to oce
!!
!!---------------------------------------------------------------------
!!-------------------------- OUT --------------------------------------
REAL(wp), DIMENSION(jpi,jpj) , INTENT(inout) :: pqfwf ! ice shelf fwf
REAL(wp), DIMENSION(jpi,jpj,jpts), INTENT(inout) :: ptsc ! T & S ice shelf cavity contents
!!-------------------------- IN --------------------------------------
INTEGER, INTENT(in) :: Kmm ! ocean time level index
INTEGER, INTENT(in) :: kt ! ocean time step
!!---------------------------------------------------------------------
LOGICAL :: lit
INTEGER :: nit, ji, jj, ikt
REAL(wp) :: zerr
REAL(wp) :: zcoef, zdku, zdkv
REAL(wp), DIMENSION(jpi,jpj) :: zqlat, zqoce, zqhc, zqh ! heat fluxes
REAL(wp), DIMENSION(jpi,jpj) :: zqh_b, zRc !
REAL(wp), DIMENSION(jpi,jpj) :: zgammat, zgammas ! exchange coeficient
REAL(wp), DIMENSION(jpi,jpj) :: zttbl, zstbl ! temp. and sal. in top boundary layer
!!---------------------------------------------------------------------
!
! compute T/S/U/V for the top boundary layer
CALL isf_tbl(Kmm, ts(:,:,:,jp_tem,Kmm), zttbl(:,:),'T', misfkt_cav, rhisf_tbl_cav, misfkb_cav, rfrac_tbl_cav )
CALL isf_tbl(Kmm, ts(:,:,:,jp_sal,Kmm), zstbl(:,:),'T', misfkt_cav, rhisf_tbl_cav, misfkb_cav, rfrac_tbl_cav )
!
! output T/S/U/V for the top boundary layer
CALL iom_put('ttbl_cav',zttbl(:,:) * mskisf_cav(:,:))
CALL iom_put('stbl' ,zstbl(:,:) * mskisf_cav(:,:))
!
! initialisation
IF ( TRIM(cn_gammablk) == 'vel_stab' ) THEN
zqoce(:,:) = -pqfwf(:,:) * rLfusisf !
zqh_b(:,:) = ptsc(:,:,jp_tem) * rho0_rcp ! last time step total heat fluxes (to speed up convergence)
DO_2D( 0, 0, 0, 0 )
ikt = mikt(ji,jj)
! compute Rc number (as done in zdfric.F90)
!!gm better to do it like in the new zdfric.F90 i.e. avm weighted Ri computation
zcoef = 0.5_wp / e3w(ji,jj,ikt+1,Kmm)
! ! shear of horizontal velocity
zdku = zcoef * ( uu(ji-1,jj ,ikt ,Kmm) + uu(ji,jj,ikt ,Kmm) &
& -uu(ji-1,jj ,ikt+1,Kmm) - uu(ji,jj,ikt+1,Kmm) )
zdkv = zcoef * ( vv(ji ,jj-1,ikt ,Kmm) + vv(ji,jj,ikt ,Kmm) &
& -vv(ji ,jj-1,ikt+1,Kmm) - vv(ji,jj,ikt+1,Kmm) )
! ! richardson number (minimum value set to zero)
zRc(ji,jj) = MAX(rn2(ji,jj,ikt+1), 1.e-20_wp) / MAX( zdku*zdku + zdkv*zdkv, 1.e-20_wp )
END_2D
CALL lbc_lnk( 'isfmlt', zRc, 'T', 1._wp )
ENDIF
!
! compute ice shelf melting
nit = 1 ; lit = .TRUE.
DO WHILE ( lit ) ! maybe just a constant number of iteration as in blk_core is fine
!
! compute gammat everywhere (2d)
! useless if melt specified
IF ( TRIM(cn_isfcav_mlt) .NE. 'spe' ) THEN
CALL isfcav_gammats( Kmm, zttbl, zstbl, zqoce , pqfwf, zRc, &
& zgammat, zgammas )
END IF
!
! compute tfrz, latent heat and melt (2d)
CALL isfcav_mlt(kt, zgammat, zgammas, zttbl, zstbl, &
& zqhc , zqoce, pqfwf )
!
! define if we need to iterate
SELECT CASE ( cn_gammablk )
CASE ( 'spe','vel' )
! no convergence needed
lit = .FALSE.
CASE ( 'vel_stab' )
! compute error between 2 iterations
zerr = 0._wp
DO_2D( 0, 0, 0, 0 )
zerr = MAX( zerr, ABS(zqhc(ji,jj)+zqoce(ji,jj) - zqh_b(ji,jj)) )
END_2D
CALL mpp_max( 'isfcav', zerr ) ! max over the global domain
!
! define if iteration needed
IF (nit >= 100) THEN ! too much iteration
CALL ctl_stop( 'STOP', 'isf_cav: vel_stab gamma formulation had too many iterations ...' )
ELSE IF ( zerr <= 0.01_wp ) THEN ! convergence is achieve
lit = .FALSE.
ELSE ! converge is not yet achieve
nit = nit + 1
zqh_b(:,:) = zqhc(:,:)+zqoce(:,:)
END IF
END SELECT
!
END DO
!
DO_2D( nn_hls, nn_hls, nn_hls, nn_hls )
! compute heat and water flux ( > 0 from isf to oce)
pqfwf(ji,jj) = pqfwf(ji,jj) * mskisf_cav(ji,jj)
zqoce(ji,jj) = zqoce(ji,jj) * mskisf_cav(ji,jj)
zqhc (ji,jj) = zqhc(ji,jj) * mskisf_cav(ji,jj)
!
! compute heat content flux ( > 0 from isf to oce)
zqlat(ji,jj) = - pqfwf(ji,jj) * rLfusisf ! 2d latent heat flux (W/m2)
!
! total heat flux ( > 0 from isf to oce)
zqh(ji,jj) = ( zqhc (ji,jj) + zqoce(ji,jj) )
!
! set temperature content
ptsc(ji,jj,jp_tem) = zqh(ji,jj) * r1_rho0_rcp
END_2D
CALL lbc_lnk( 'isfmlt', pqfwf, 'T', 1.0_wp)
!
! output fluxes
CALL isf_diags_flx( Kmm, misfkt_cav, misfkb_cav, rhisf_tbl_cav, rfrac_tbl_cav, 'cav', pqfwf, zqoce, zqlat, zqhc)
!
#if ! defined key_RK3
! MLF: write restart variables (qoceisf, qhcisf, fwfisf for now and before)
IF (lrst_oce) CALL isfrst_write(kt, 'cav', ptsc, pqfwf)
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
!
IF ( ln_isfdebug ) THEN
IF(lwp) WRITE(numout,*) ''
CALL debug('isf_cav: ptsc T',ptsc(:,:,1))
CALL debug('isf_cav: ptsc S',ptsc(:,:,2))
CALL debug('isf_cav: pqfwf fwf',pqfwf(:,:))
IF(lwp) WRITE(numout,*) ''
END IF
!
END SUBROUTINE isf_cav
SUBROUTINE isf_cav_init
!!---------------------------------------------------------------------
!! *** ROUTINE isf_cav_init ***
!!
!! ** Purpose : initialisation of variable needed to compute melt under an ice shelf
!!
!!----------------------------------------------------------------------
INTEGER :: ierr
!!---------------------------------------------------------------------
!
!==============
! 0: allocation
!==============
!
CALL isf_alloc_cav()
!
!==================
! 1: initialisation
!==================
!
! top and bottom level of the 'top boundary layer'
misfkt_cav(:,:) = mikt(:,:) ; misfkb_cav(:,:) = 1
!
! thickness of 'tbl' and fraction of bottom cell affected by 'tbl'
rhisf_tbl_cav(:,:) = 0.0_wp ; rfrac_tbl_cav(:,:) = 0.0_wp
!
! cavity mask
mskisf_cav(:,:) = (1._wp - tmask(:,:,1)) * ssmask(:,:)
!
#if ! defined key_RK3
!================
! 2: activate restart
!================
!
!================
! 3: read restart
!================
!
! MLF: read cav variable from restart
IF ( ln_rstart ) CALL isfrst_read('cav', risf_cav_tsc, fwfisf_cav, risf_cav_tsc_b, fwfisf_cav_b)
!
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
!==========================================
! 3: specific allocation and initialisation (depending of scheme choice)
!==========================================
!
SELECT CASE ( TRIM(cn_isfcav_mlt) )
CASE( 'spe' )
ALLOCATE( sf_isfcav_fwf(1), STAT=ierr )
ALLOCATE( sf_isfcav_fwf(1)%fnow(jpi,jpj,1), sf_isfcav_fwf(1)%fdta(jpi,jpj,1,2) )
CALL fld_fill( sf_isfcav_fwf, (/ sn_isfcav_fwf /), cn_isfdir, 'isf_cav_init', 'read fresh water flux isf data', 'namisf' )
IF(lwp) WRITE(numout,*)
IF(lwp) WRITE(numout,*) ' ==>> The ice shelf melt inside the cavity is read from forcing files'
CASE( '2eq' )
IF(lwp) WRITE(numout,*)
IF(lwp) WRITE(numout,*) ' ==>> The original ISOMIP melt formulation is used to compute melt under the ice shelves'
CASE( '3eq' )
! coeficient for linearisation of potential tfreez
! Crude approximation for pressure (but commonly used)
IF ( ln_teos10 ) THEN ! linearisation from Jourdain et al. (2017)
risf_lamb1 =-0.0564_wp
risf_lamb2 = 0.0773_wp
risf_lamb3 =-7.8633e-8 * grav * rho0
ELSE ! linearisation from table 4 (Asay-Davis et al., 2015)
risf_lamb1 =-0.0573_wp
risf_lamb2 = 0.0832_wp
risf_lamb3 =-7.5300e-8 * grav * rho0
ENDIF
IF(lwp) WRITE(numout,*)
IF(lwp) WRITE(numout,*) ' ==>> The 3 equations melt formulation is used to compute melt under the ice shelves'
CASE DEFAULT
CALL ctl_stop(' cn_isfcav_mlt method unknown (spe, 2eq, 3eq), check namelist')
END SELECT
!
END SUBROUTINE isf_cav_init
END MODULE isfcav