SUBROUTINE VISBECK_CALC( 1,5OVISCALC.20
& athkdft OVISCALC.21
*CALL ARGOC2DG 
OVISCALC.22
&,CST,DXT,DYT OVISCALC.23
&,IMT,JMT,IMT_VIS,JMT_VIS,IMT_IPD,IMTM2,JMT_GLOBAL OVISCALC.24
&,JST,JFIN,J_1,J_JMT,O_MYPE,L_OVISHADCM4 OVISCALC.25
&) OVISCALC.26
! Description: This subroutine handles the main length scale OVISCALC.27
! calculations for the VISBECK scheme. Use of this OVISCALC.28
! subroutine allows memory reuse which is important OVISCALC.29
! because several large arrays are only needed OVISCALC.30
! temporarily. OVISCALC.31
! Calculate length scale for Visbeck scheme if this OVISCALC.32
! is a mixing timestep. lscale is the min number of OVISCALC.33
! grid points needed to find a value of tmin1 le OVISCALC.34
! tmin1_max (set to min 1 max 7). OVISCALC.35
! OVISCALC.36
! Author: R. Hill OVISCALC.37
! OVISCALC.38
! Date: June 1998 OVISCALC.39
! OVISCALC.40
! Modification History OVISCALC.41
! OVISCALC.42
! Date Name Description OVISCALC.43
! ------ ---------- ------------------------------------------ OVISCALC.44
! OVISCALC.45
!################################################################### OVISCALC.46
IMPLICIT NONE OVISCALC.47
OVISCALC.48
*CALL PARVARS OVISCALC.49
OVISCALC.51
!----------------------------------------------------------------- OVISCALC.52
! Input dimensions etc OVISCALC.53
!----------------------------------------------------------------- OVISCALC.54
INTEGER OVISCALC.55
& IMT,JMT,IMT_VIS,JMT_VIS,IMT_IPD,IMTM2,JMT_GLOBAL OVISCALC.56
&,JST,JFIN,J_1,J_JMT,O_MYPE OVISCALC.57
OVISCALC.58
REAL OVISCALC.59
& athkdft(imt_vis,jmt_vis) ! IN/OUT diffsn coeff on T grid OVISCALC.60
&,CST(JMT) ! IN OVISCALC.61
&,DXT(IMT) ! IN OVISCALC.62
&,DYT(JMT) ! IN OVISCALC.63
OVISCALC.64
LOGICAL OVISCALC.65
& L_OVISHADCM4 ! hadcm4 version of visbeck scheme OVISCALC.66
OVISCALC.67
*CALL TYPOC2DG PXORDER.40
PXORDER.41
!====================================================================== OVISCALC.68
! Local variables to this routine. OVISCALC.69
!====================================================================== OVISCALC.70
INTEGER I OVISCALC.71
&, J OVISCALC.72
&,ngap ! \ gaps to N,S,E and W resp. used for OVISCALC.73
&,sgap ! | calculating length scale for Visbeck OVISCALC.74
&,egap ! | scheme OVISCALC.75
&,wgap ! / OVISCALC.76
&,ipos,jpos ! \ used for calculating length scale OVISCALC.77
&,nstot,ewtot ! / for Visbeck scheme OVISCALC.78
&,info ! return code from scatter_field,gather_field OVISCALC.79
OVISCALC.80
REAL tmin1_max ! lscale=min no. grdpts to find tmin1 < tmin1_max OVISCALC.81
&,CST_GLOBAL(jmt_global) ! global version of CST OVISCALC.82
&,DYT_GLOBAL(jmt_global) ! global version of DYT OVISCALC.83
&,tmin1_global(imt,jmt_global) ! global field of tmin1 OVISCALC.84
&,fract ! used for calculating length scale OVISCALC.85
&,athkdft_max OVISCALC.86
&,athkdft_min ! Max and min values allowed for athkdft OVISCALC.87
&,lscale(imt_vis,jmt_vis) ! length scale OVISCALC.88
&,lscale_global(imt_ipd,jmt_global) ! global field of lscale OVISCALC.89
!====================================================================== OVISCALC.90
OVISCALC.91
c The value for tmin1_max is hardwired at the moment and was OVISCALC.92
c chosen as a result of experimentation. This needs further work OVISCALC.93
c and may be altered in the future. OVISCALC.94
IF (L_OVISHADCM4) THEN OVISCALC.95
tmin1_max=1.7e-6 OVISCALC.96
ELSE OVISCALC.97
tmin1_max=1.4e-6 OVISCALC.98
ENDIF OVISCALC.99
OVISCALC.100
*IF DEF,MPP OVISCALC.101
c The following calculation needs to be on 1PE for MPP machine OVISCALC.102
c since requires several rows to N or S OVISCALC.103
c Create a global copy of CST and DYT OVISCALC.104
CALL O_SMARTPASS(1,1,CST(J_1),CST_GLOBAL OVISCALC.105
& ,JFIN-JST+1,JMT_GLOBAL,JST,2) OVISCALC.106
CALL O_SMARTPASS(1,1,DYT(J_1),DYT_GLOBAL OVISCALC.107
& ,JFIN-JST+1,JMT_GLOBAL,JST,2) OVISCALC.108
c Gather field tmin1 onto processor 0 OVISCALC.109
CALL GATHER_FIELD(tmin1,tmin1_global,imt,jmt,imt, OVISCALC.110
& jmt_global,0,GC_ALL_PROC_GROUP,info) OVISCALC.111
*ELSE OVISCALC.112
C Set up for non mpp code. OVISCALC.113
DO J = J_1, J_JMT OVISCALC.114
CST_GLOBAL(J)=CST(J) OVISCALC.115
DYT_GLOBAL(J)=DYT(J) OVISCALC.116
do i=1,imt OVISCALC.117
tmin1_global(i,j)=tmin1(i,j) OVISCALC.118
enddo OVISCALC.119
ENDDO OVISCALC.120
*ENDIF OVISCALC.121
c Calculate length scale OVISCALC.122
*IF DEF,MPP OVISCALC.123
IF (O_MYPE.EQ.0) THEN OVISCALC.124
*ENDIF OVISCALC.125
do j=1,jmt_global OVISCALC.126
do i=1,imt OVISCALC.127
if (tmin1_global(i,j) .le. tmin1_max) then OVISCALC.128
if (L_OVISHADCM4) THEN OVISCALC.129
lscale_global(i,j)=DYT_GLOBAL(j) OVISCALC.130
else OVISCALC.131
lscale_global(i,j)=1. OVISCALC.132
endif OVISCALC.133
else OVISCALC.134
c scan north OVISCALC.135
ngap=0 OVISCALC.136
100 continue OVISCALC.137
ngap=ngap+1 OVISCALC.138
jpos=j+ngap OVISCALC.139
if (jpos .gt. jmt_global .or. ngap .gt. 10) then OVISCALC.140
goto 200 OVISCALC.141
else OVISCALC.142
if (tmin1_global(i,jpos) .le. tmin1_max OVISCALC.143
& ) goto 200 OVISCALC.144
endif OVISCALC.145
goto 100 OVISCALC.146
200 continue OVISCALC.147
c scan south OVISCALC.148
sgap=0 OVISCALC.149
300 continue OVISCALC.150
sgap=sgap+1 OVISCALC.151
jpos=j-sgap OVISCALC.152
if (jpos .lt. 1 .or. sgap .gt. 10) then OVISCALC.153
goto 400 OVISCALC.154
else OVISCALC.155
if (tmin1_global(i,jpos) .le. tmin1_max OVISCALC.156
& ) goto 400 OVISCALC.157
endif OVISCALC.158
goto 300 OVISCALC.159
400 continue OVISCALC.160
c scan west OVISCALC.161
wgap=0 OVISCALC.162
500 continue OVISCALC.163
wgap=wgap+1 OVISCALC.164
ipos=i-wgap OVISCALC.165
if (wgap .gt. 10) goto 600 OVISCALC.166
if (ipos .lt. 1 ) ipos=ipos+imtm2 OVISCALC.167
if (tmin1_global(ipos,j) .le. tmin1_max OVISCALC.168
& ) goto 600 OVISCALC.169
goto 500 OVISCALC.170
600 continue OVISCALC.171
c scan east OVISCALC.172
egap=0 OVISCALC.173
700 continue OVISCALC.174
egap=egap+1 OVISCALC.175
ipos=i+egap OVISCALC.176
if (egap .gt. 10) goto 800 OVISCALC.177
if (ipos .gt. imt) ipos=ipos-imt OVISCALC.178
if (tmin1_global(ipos,j) .le. tmin1_max OVISCALC.179
& ) goto 800 OVISCALC.180
goto 700 OVISCALC.181
800 continue OVISCALC.182
OVISCALC.183
c Now find out which dirn is the least NS or EW OVISCALC.184
OVISCALC.185
nstot=DYT_GLOBAL(j)*float(ngap+sgap) OVISCALC.186
ewtot=CST_GLOBAL(j)*DXT(i)*float(egap+wgap) OVISCALC.187
OVISCALC.188
if (nstot .lt. ewtot) then OVISCALC.189
fract=min(float(ngap),float(sgap))/ OVISCALC.190
& max(float(ngap),float(sgap)) OVISCALC.191
lscale_global(i,j)=fract*nstot OVISCALC.192
else OVISCALC.193
fract=min(float(egap),float(wgap))/ OVISCALC.194
& max(float(egap),float(wgap)) OVISCALC.195
lscale_global(i,j)=fract*ewtot OVISCALC.196
endif OVISCALC.197
if (L_OVISHADCM4) THEN OVISCALC.198
lscale_global(i,j)=max(dyt_global(j),lscale_global(i,j)) OVISCALC.199
endif OVISCALC.200
endif OVISCALC.201
enddo OVISCALC.202
enddo OVISCALC.203
*IF DEF,MPP OVISCALC.204
ENDIF ! if O_MYPE=0 OVISCALC.205
*ENDIF OVISCALC.206
*IF DEF,MPP OVISCALC.207
c Scatter lscale and tmin1 back to individual processors OVISCALC.208
CALL SCATTER_FIELD(lscale,lscale_global,imt,jmt,imt, OVISCALC.209
& jmt_global,0,GC_ALL_PROC_GROUP,info) OVISCALC.210
CALL SCATTER_FIELD(tmin1,tmin1_global,imt,jmt,imt, OVISCALC.211
& jmt_global,0,GC_ALL_PROC_GROUP,info) OVISCALC.212
*ELSE OVISCALC.213
C Set up for non mpp code. OVISCALC.214
DO J = J_1, J_JMT OVISCALC.215
do i=1,imt OVISCALC.216
lscale(i,j)=lscale_global(i,j) OVISCALC.217
tmin1(i,j)=tmin1_global(i,j) OVISCALC.218
enddo OVISCALC.219
ENDDO OVISCALC.220
*ENDIF OVISCALC.221
c Set the thickness diffusion coefficent. OVISCALC.222
c The length scale just calculated is the number of grid points OVISCALC.223
c multiplied by the length of each grid point so the length scale OVISCALC.224
c is now in centimetres. OVISCALC.225
c The value 0.015 is given by Visbeck et. al. OVISCALC.226
c The minimum and maximum allowed thickness diffusion is also set. OVISCALC.227
c (hardwired here at the moment) OVISCALC.228
c Reference: Visbeck, M. et al, On the specification of eddy OVISCALC.229
c transfer coefficients in coarse resolution ocean OVISCALC.230
c circulation models. J. Phys. Oceanogr.,27, p 381-402. OVISCALC.231
c OVISCALC.232
if (L_OVISHADCM4) THEN OVISCALC.233
athkdft_min=100.e4 OVISCALC.234
else OVISCALC.235
athkdft_min=350.e4 OVISCALC.236
endif OVISCALC.237
OVISCALC.238
athkdft_max=2000.e4 OVISCALC.239
OVISCALC.240
do j=j_1,j_jmt OVISCALC.241
do i=1,imt OVISCALC.242
ATHKDFT(i,j)=0.015*tmin1(i,j)*lscale(i,j)*lscale(i,j) OVISCALC.243
if (ATHKDFT(i,j).lt.athkdft_min) ATHKDFT(i,j)=athkdft_min OVISCALC.244
if (ATHKDFT(i,j).gt.athkdft_max) ATHKDFT(i,j)=athkdft_max OVISCALC.245
enddo OVISCALC.246
enddo OVISCALC.247
OVISCALC.248
RETURN OVISCALC.249
END OVISCALC.250
*ENDIF OVISCALC.251