/[MITgcm]/MITgcm/model/src/calc_gs.F
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Contents of /MITgcm/model/src/calc_gs.F

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Revision 1.9 - (show annotations) (download)
Wed Jun 17 21:07:01 1998 UTC (25 years, 11 months ago) by adcroft
Branch: MAIN
Changes since 1.8: +4 -2 lines
Introduced time-dependant forcing, loaded and interpolated in
load_external_fields.F in a subroutine load_interpolate_forcing().
Control is by one logical and two real variables in PARAMS.h:
periodicExternalForcing, externForcingCycle and externForcingPeriod.
The code in load_external_fields.F is "customized" so needs to
be edited for non-global type runs. We'll tidy it up later.

1 C $Header: /u/gcmpack/models/MITgcmUV/model/src/calc_gs.F,v 1.8 1998/06/15 05:13:55 cnh Exp $
2
3 #include "CPP_EEOPTIONS.h"
4
5 CStartOfInterFace
6 SUBROUTINE CALC_GS(
7 I bi,bj,iMin,iMax,jMin,jMax,k,kM1,kUp,kDown,
8 I xA,yA,uTrans,vTrans,wTrans,maskup,
9 I K13,K23,KappaZS,KapGM,
10 U af,df,fZon,fMer,fVerS,
11 I myThid )
12 C /==========================================================\
13 C | SUBROUTINE CALC_GS |
14 C | o Calculate the salt tendency terms. |
15 C |==========================================================|
16 C | A procedure called EXTERNAL_FORCING_S is called from |
17 C | here. These procedures can be used to add per problem |
18 C | E-P flux source terms. |
19 C | Note: Although it is slightly counter-intuitive the |
20 C | EXTERNAL_FORCING routine is not the place to put |
21 C | file I/O. Instead files that are required to |
22 C | calculate the external source terms are generally |
23 C | read during the model main loop. This makes the |
24 C | logisitics of multi-processing simpler and also |
25 C | makes the adjoint generation simpler. It also |
26 C | allows for I/O to overlap computation where that |
27 C | is supported by hardware. |
28 C | Aside from the problem specific term the code here |
29 C | forms the tendency terms due to advection and mixing |
30 C | The baseline implementation here uses a centered |
31 C | difference form for the advection term and a tensorial |
32 C | divergence of a flux form for the diffusive term. The |
33 C | diffusive term is formulated so that isopycnal mixing and|
34 C | GM-style subgrid-scale terms can be incorporated b simply|
35 C | setting the diffusion tensor terms appropriately. |
36 C \==========================================================/
37 IMPLICIT NONE
38
39 C == GLobal variables ==
40 #include "SIZE.h"
41 #include "DYNVARS.h"
42 #include "EEPARAMS.h"
43 #include "PARAMS.h"
44 #include "GRID.h"
45 #include "FFIELDS.h"
46
47 C == Routine arguments ==
48 C fZon - Work array for flux of temperature in the east-west
49 C direction at the west face of a cell.
50 C fMer - Work array for flux of temperature in the north-south
51 C direction at the south face of a cell.
52 C fVerS - Flux of salt (S) in the vertical
53 C direction at the upper(U) and lower(D) faces of a cell.
54 C maskUp - Land mask used to denote base of the domain.
55 C xA - Tracer cell face area normal to X
56 C yA - Tracer cell face area normal to X
57 C uTrans - Zonal volume transport through cell face
58 C vTrans - Meridional volume transport through cell face
59 C wTrans - Vertical volume transport through cell face
60 C af - Advective flux component work array
61 C df - Diffusive flux component work array
62 C bi, bj, iMin, iMax, jMin, jMax - Range of points for which calculation
63 C results will be set.
64 C myThid - Instance number for this innvocation of CALC_GT
65 _RL fZon (1-OLx:sNx+OLx,1-OLy:sNy+OLy)
66 _RL fMer (1-OLx:sNx+OLx,1-OLy:sNy+OLy)
67 _RL fVerS (1-OLx:sNx+OLx,1-OLy:sNy+OLy,2)
68 _RS xA (1-OLx:sNx+OLx,1-OLy:sNy+OLy)
69 _RS yA (1-OLx:sNx+OLx,1-OLy:sNy+OLy)
70 _RL uTrans(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
71 _RL vTrans(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
72 _RL wTrans(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
73 _RS maskUp(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
74 _RL K13 (1-OLx:sNx+OLx,1-OLy:sNy+OLy,Nz)
75 _RL K23 (1-OLx:sNx+OLx,1-OLy:sNy+OLy,Nz)
76 _RL KappaZS(1-OLx:sNx+OLx,1-OLy:sNy+OLy,Nz)
77 _RL KapGM (1-OLx:sNx+OLx,1-OLy:sNy+OLy)
78 _RL af (1-OLx:sNx+OLx,1-OLy:sNy+OLy)
79 _RL df (1-OLx:sNx+OLx,1-OLy:sNy+OLy)
80 INTEGER k,kUp,kDown,kM1
81 INTEGER bi,bj,iMin,iMax,jMin,jMax
82 INTEGER myThid
83 CEndOfInterface
84
85 C == Local variables ==
86 C I, J, K - Loop counters
87 INTEGER i,j
88 LOGICAL TOP_LAYER
89 _RL afFacS, dfFacS
90 _RL dSdx(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
91 _RL dSdy(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
92
93 afFacS = 1. _d 0
94 dfFacS = 1. _d 0
95 TOP_LAYER = K .EQ. 1
96
97 C--- Calculate advective and diffusive fluxes between cells.
98
99 C-- Zonal flux (fZon is at west face of "salt" cell)
100 C Advective component of zonal flux
101 DO j=jMin,jMax
102 DO i=iMin,iMax
103 af(i,j) =
104 & uTrans(i,j)*(salt(i,j,k,bi,bj)+salt(i-1,j,k,bi,bj))*0.5 _d 0
105 ENDDO
106 ENDDO
107 C Zonal tracer gradient
108 DO j=jMin,jMax
109 DO i=iMin,iMax
110 dSdx(i,j) = _rdxC(i,j,bi,bj)*
111 & (salt(i,j,k,bi,bj)-salt(i-1,j,k,bi,bj))
112 ENDDO
113 ENDDO
114 C Diffusive component of zonal flux
115 DO j=jMin,jMax
116 DO i=iMin,iMax
117 df(i,j) = -(diffKhS+0.5*(KapGM(i,j)+KapGM(i-1,j)))*
118 & xA(i,j)*dSdx(i,j)
119 ENDDO
120 ENDDO
121 C Net zonal flux
122 DO j=jMin,jMax
123 DO i=iMin,iMax
124 fZon(i,j) = afFacS*af(i,j) + dfFacS*df(i,j)
125 ENDDO
126 ENDDO
127
128 C-- Meridional flux (fMer is at south face of "salt" cell)
129 C Advective component of meridional flux
130 DO j=jMin,jMax
131 DO i=iMin,iMax
132 C Advective component of meridional flux
133 af(i,j) =
134 & vTrans(i,j)*(salt(i,j,k,bi,bj)+salt(i,j-1,k,bi,bj))*0.5 _d 0
135 ENDDO
136 ENDDO
137 C Zonal tracer gradient
138 DO j=jMin,jMax
139 DO i=iMin,iMax
140 dSdy(i,j) = _rdyC(i,j,bi,bj)*
141 & (salt(i,j,k,bi,bj)-salt(i,j-1,k,bi,bj))
142 ENDDO
143 ENDDO
144 C Diffusive component of meridional flux
145 DO j=jMin,jMax
146 DO i=iMin,iMax
147 df(i,j) = -(diffKhS+0.5*(KapGM(i,j)+KapGM(i,j-1)))*
148 & yA(i,j)*dSdy(i,j)
149 ENDDO
150 ENDDO
151 C Net meridional flux
152 DO j=jMin,jMax
153 DO i=iMin,iMax
154 fMer(i,j) = afFacS*af(i,j) + dfFacS*df(i,j)
155 ENDDO
156 ENDDO
157
158 C-- Interpolate terms for Redi/GM scheme
159 DO j=jMin,jMax
160 DO i=iMin,iMax
161 dSdx(i,j) = 0.5*(
162 & +0.5*(_maskW(i+1,j,k,bi,bj)*_rdxC(i+1,j,bi,bj)*
163 & (salt(i+1,j,k,bi,bj)-salt(i,j,k,bi,bj))
164 & +_maskW(i,j,k,bi,bj)*_rdxC(i,j,bi,bj)*
165 & (salt(i,j,k,bi,bj)-salt(i-1,j,k,bi,bj)))
166 & +0.5*(_maskW(i+1,j,km1,bi,bj)*_rdxC(i+1,j,bi,bj)*
167 & (salt(i+1,j,km1,bi,bj)-salt(i,j,km1,bi,bj))
168 & +_maskW(i,j,km1,bi,bj)*_rdxC(i,j,bi,bj)*
169 & (salt(i,j,km1,bi,bj)-salt(i-1,j,km1,bi,bj)))
170 & )
171 ENDDO
172 ENDDO
173 DO j=jMin,jMax
174 DO i=iMin,iMax
175 dSdy(i,j) = 0.5*(
176 & +0.5*(_maskS(i,j,k,bi,bj)*_rdyC(i,j,bi,bj)*
177 & (salt(i,j,k,bi,bj)-salt(i,j-1,k,bi,bj))
178 & +_maskS(i,j+1,k,bi,bj)*_rdyC(i,j+1,bi,bj)*
179 & (salt(i,j+1,k,bi,bj)-salt(i,j,k,bi,bj)))
180 & +0.5*(_maskS(i,j,km1,bi,bj)*_rdyC(i,j,bi,bj)*
181 & (salt(i,j,km1,bi,bj)-salt(i,j-1,km1,bi,bj))
182 & +_maskS(i,j+1,km1,bi,bj)*_rdyC(i,j+1,bi,bj)*
183 & (salt(i,j+1,km1,bi,bj)-salt(i,j,km1,bi,bj)))
184 & )
185 ENDDO
186 ENDDO
187
188 C-- Vertical flux (fVerS) above
189 C Advective component of vertical flux
190 C Note: For K=1 then KM1=1 this gives a barZ(T) = T
191 C (this plays the role of the free-surface correction)
192 DO j=jMin,jMax
193 DO i=iMin,iMax
194 af(i,j) =
195 & wTrans(i,j)*(salt(i,j,k,bi,bj)+salt(i,j,kM1,bi,bj))*0.5 _d 0
196 ENDDO
197 ENDDO
198 C Diffusive component of vertical flux
199 C Note: For K=1 then KM1=1 this gives a dS/dz = 0 upper
200 C boundary condition.
201 DO j=jMin,jMax
202 DO i=iMin,iMax
203 df(i,j) = _zA(i,j,bi,bj)*(
204 & -KapGM(i,j)*K13(i,j,k)*dSdx(i,j)
205 & -KapGM(i,j)*K23(i,j,k)*dSdy(i,j)
206 & )
207 ENDDO
208 ENDDO
209 IF (.NOT.implicitDiffusion) THEN
210 DO j=jMin,jMax
211 DO i=iMin,iMax
212 df(i,j) = df(i,j) + _zA(i,j,bi,bj)*(
213 & -KappaZS(i,j,k)*rdzC(k)
214 & *(salt(i,j,kM1,bi,bj)-salt(i,j,k,bi,bj))
215 & )
216 ENDDO
217 ENDDO
218 ENDIF
219 C Net vertical flux
220 DO j=jMin,jMax
221 DO i=iMin,iMax
222 fVerS(i,j,kUp) = ( afFacS*af(i,j)+ dfFacS*df(i,j) )*maskUp(i,j)
223 ENDDO
224 ENDDO
225 IF ( TOP_LAYER ) THEN
226 DO j=jMin,jMax
227 DO i=iMin,iMax
228 fVerS(i,j,kUp) = afFacS*af(i,j)*freeSurfFac
229 ENDDO
230 ENDDO
231 ENDIF
232
233 C-- Tendency is minus divergence of the fluxes.
234 C Note. Tendency terms will only be correct for range
235 C i=iMin+1:iMax-1, j=jMin+1:jMax-1. Edge points
236 C will contain valid floating point numbers but
237 C they are not algorithmically correct. These points
238 C are not used.
239 DO j=jMin,jMax
240 DO i=iMin,iMax
241 C & -_rhFacC(i,j,k,bi,bj)*rdzF(k)*_rdxF(i,j,bi,bj)*_rdyF(i,j,bi,bj)
242 C & -_rhFacC(i,j,k,bi,bj)*rdzF(k)/_zA(i,j,bi,bj)
243 C #define _rVolS(i,j,k,bi,bj) _rhFacC(i,j,k,bi,bj)*rdzF(k)*_rdxF(i,j,bi,bj)*_rdyF(i,j,bi,bj)
244 #define _rVolS(i,j,k,bi,bj) _rhFacC(i,j,k,bi,bj)*rdzF(k)/_zA(i,j,bi,bj)
245 gS(i,j,k,bi,bj)=
246 & -_rVolS(i,j,k,bi,bj)
247 & *(
248 & +( fZon(i+1,j)-fZon(i,j) )
249 & +( fMer(i,j+1)-fMer(i,j) )
250 & +( fVerS(i,j,kUp)-fVerS(i,j,kDown) )
251 & )
252 ENDDO
253 ENDDO
254
255 C-- External P-E forcing term(s)
256 C o Surface relaxation term
257 IF ( TOP_LAYER ) THEN
258 DO j=jMin,jMax
259 DO i=iMin,iMax
260 gS(i,j,k,bi,bj)=gS(i,j,k,bi,bj)
261 & +maskUp(i,j)*(
262 & -lambdaSaltClimRelax*(salt(i,j,k,bi,bj)-SSS(i,j,bi,bj))
263 & -EmPpR(i,j,bi,bj) )
264 ENDDO
265 ENDDO
266 ENDIF
267
268
269 RETURN
270 END

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