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

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Revision 1.11 - (show annotations) (download)
Wed Jul 15 22:22:24 1998 UTC (25 years, 9 months ago) by adcroft
Branch: MAIN
CVS Tags: checkpoint13, branch-point-rdot
Branch point for: branch-rdot
Changes since 1.10: +2 -2 lines
After great excitement and confusion we discovered that we didn't have
a bug or sign error in the E-P flux. However, we did think it prudent
to use a better name for it. EmPpR is now EmPmR and it really is E-P-R!

1 C $Header: /u/gcmpack/models/MITgcmUV/model/src/calc_gs.F,v 1.10 1998/06/22 15:26:25 adcroft 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,maskC,
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 maskC - Land mask for salt cells (used in TOP_LAYER only)
56 C xA - Tracer cell face area normal to X
57 C yA - Tracer cell face area normal to X
58 C uTrans - Zonal volume transport through cell face
59 C vTrans - Meridional volume transport through cell face
60 C wTrans - Vertical volume transport through cell face
61 C af - Advective flux component work array
62 C df - Diffusive flux component work array
63 C bi, bj, iMin, iMax, jMin, jMax - Range of points for which calculation
64 C results will be set.
65 C myThid - Instance number for this innvocation of CALC_GT
66 _RL fZon (1-OLx:sNx+OLx,1-OLy:sNy+OLy)
67 _RL fMer (1-OLx:sNx+OLx,1-OLy:sNy+OLy)
68 _RL fVerS (1-OLx:sNx+OLx,1-OLy:sNy+OLy,2)
69 _RS xA (1-OLx:sNx+OLx,1-OLy:sNy+OLy)
70 _RS yA (1-OLx:sNx+OLx,1-OLy:sNy+OLy)
71 _RL uTrans(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
72 _RL vTrans(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
73 _RL wTrans(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
74 _RS maskUp(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
75 _RS maskC (1-OLx:sNx+OLx,1-OLy:sNy+OLy)
76 _RL K13 (1-OLx:sNx+OLx,1-OLy:sNy+OLy,Nz)
77 _RL K23 (1-OLx:sNx+OLx,1-OLy:sNy+OLy,Nz)
78 _RL KappaZS(1-OLx:sNx+OLx,1-OLy:sNy+OLy,Nz)
79 _RL KapGM (1-OLx:sNx+OLx,1-OLy:sNy+OLy)
80 _RL af (1-OLx:sNx+OLx,1-OLy:sNy+OLy)
81 _RL df (1-OLx:sNx+OLx,1-OLy:sNy+OLy)
82 INTEGER k,kUp,kDown,kM1
83 INTEGER bi,bj,iMin,iMax,jMin,jMax
84 INTEGER myThid
85 CEndOfInterface
86
87 C == Local variables ==
88 C I, J, K - Loop counters
89 INTEGER i,j
90 LOGICAL TOP_LAYER
91 _RL afFacS, dfFacS
92 _RL dSdx(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
93 _RL dSdy(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
94
95 afFacS = 1. _d 0
96 dfFacS = 1. _d 0
97 TOP_LAYER = K .EQ. 1
98
99 C--- Calculate advective and diffusive fluxes between cells.
100
101 C-- Zonal flux (fZon is at west face of "salt" cell)
102 C Advective component of zonal flux
103 DO j=jMin,jMax
104 DO i=iMin,iMax
105 af(i,j) =
106 & uTrans(i,j)*(salt(i,j,k,bi,bj)+salt(i-1,j,k,bi,bj))*0.5 _d 0
107 ENDDO
108 ENDDO
109 C Zonal tracer gradient
110 DO j=jMin,jMax
111 DO i=iMin,iMax
112 dSdx(i,j) = _rdxC(i,j,bi,bj)*
113 & (salt(i,j,k,bi,bj)-salt(i-1,j,k,bi,bj))
114 ENDDO
115 ENDDO
116 C Diffusive component of zonal flux
117 DO j=jMin,jMax
118 DO i=iMin,iMax
119 df(i,j) = -(diffKhS+0.5*(KapGM(i,j)+KapGM(i-1,j)))*
120 & xA(i,j)*dSdx(i,j)
121 ENDDO
122 ENDDO
123 C Net zonal flux
124 DO j=jMin,jMax
125 DO i=iMin,iMax
126 fZon(i,j) = afFacS*af(i,j) + dfFacS*df(i,j)
127 ENDDO
128 ENDDO
129
130 C-- Meridional flux (fMer is at south face of "salt" cell)
131 C Advective component of meridional flux
132 DO j=jMin,jMax
133 DO i=iMin,iMax
134 C Advective component of meridional flux
135 af(i,j) =
136 & vTrans(i,j)*(salt(i,j,k,bi,bj)+salt(i,j-1,k,bi,bj))*0.5 _d 0
137 ENDDO
138 ENDDO
139 C Zonal tracer gradient
140 DO j=jMin,jMax
141 DO i=iMin,iMax
142 dSdy(i,j) = _rdyC(i,j,bi,bj)*
143 & (salt(i,j,k,bi,bj)-salt(i,j-1,k,bi,bj))
144 ENDDO
145 ENDDO
146 C Diffusive component of meridional flux
147 DO j=jMin,jMax
148 DO i=iMin,iMax
149 df(i,j) = -(diffKhS+0.5*(KapGM(i,j)+KapGM(i,j-1)))*
150 & yA(i,j)*dSdy(i,j)
151 ENDDO
152 ENDDO
153 C Net meridional flux
154 DO j=jMin,jMax
155 DO i=iMin,iMax
156 fMer(i,j) = afFacS*af(i,j) + dfFacS*df(i,j)
157 ENDDO
158 ENDDO
159
160 C-- Interpolate terms for Redi/GM scheme
161 DO j=jMin,jMax
162 DO i=iMin,iMax
163 dSdx(i,j) = 0.5*(
164 & +0.5*(_maskW(i+1,j,k,bi,bj)*_rdxC(i+1,j,bi,bj)*
165 & (salt(i+1,j,k,bi,bj)-salt(i,j,k,bi,bj))
166 & +_maskW(i,j,k,bi,bj)*_rdxC(i,j,bi,bj)*
167 & (salt(i,j,k,bi,bj)-salt(i-1,j,k,bi,bj)))
168 & +0.5*(_maskW(i+1,j,km1,bi,bj)*_rdxC(i+1,j,bi,bj)*
169 & (salt(i+1,j,km1,bi,bj)-salt(i,j,km1,bi,bj))
170 & +_maskW(i,j,km1,bi,bj)*_rdxC(i,j,bi,bj)*
171 & (salt(i,j,km1,bi,bj)-salt(i-1,j,km1,bi,bj)))
172 & )
173 ENDDO
174 ENDDO
175 DO j=jMin,jMax
176 DO i=iMin,iMax
177 dSdy(i,j) = 0.5*(
178 & +0.5*(_maskS(i,j,k,bi,bj)*_rdyC(i,j,bi,bj)*
179 & (salt(i,j,k,bi,bj)-salt(i,j-1,k,bi,bj))
180 & +_maskS(i,j+1,k,bi,bj)*_rdyC(i,j+1,bi,bj)*
181 & (salt(i,j+1,k,bi,bj)-salt(i,j,k,bi,bj)))
182 & +0.5*(_maskS(i,j,km1,bi,bj)*_rdyC(i,j,bi,bj)*
183 & (salt(i,j,km1,bi,bj)-salt(i,j-1,km1,bi,bj))
184 & +_maskS(i,j+1,km1,bi,bj)*_rdyC(i,j+1,bi,bj)*
185 & (salt(i,j+1,km1,bi,bj)-salt(i,j,km1,bi,bj)))
186 & )
187 ENDDO
188 ENDDO
189
190 C-- Vertical flux (fVerS) above
191 C Advective component of vertical flux
192 C Note: For K=1 then KM1=1 this gives a barZ(T) = T
193 C (this plays the role of the free-surface correction)
194 DO j=jMin,jMax
195 DO i=iMin,iMax
196 af(i,j) =
197 & wTrans(i,j)*(salt(i,j,k,bi,bj)+salt(i,j,kM1,bi,bj))*0.5 _d 0
198 ENDDO
199 ENDDO
200 C Diffusive component of vertical flux
201 C Note: For K=1 then KM1=1 this gives a dS/dz = 0 upper
202 C boundary condition.
203 DO j=jMin,jMax
204 DO i=iMin,iMax
205 df(i,j) = _zA(i,j,bi,bj)*(
206 & -KapGM(i,j)*K13(i,j,k)*dSdx(i,j)
207 & -KapGM(i,j)*K23(i,j,k)*dSdy(i,j)
208 & )
209 ENDDO
210 ENDDO
211 IF (.NOT.implicitDiffusion) THEN
212 DO j=jMin,jMax
213 DO i=iMin,iMax
214 df(i,j) = df(i,j) + _zA(i,j,bi,bj)*(
215 & -KappaZS(i,j,k)*rdzC(k)
216 & *(salt(i,j,kM1,bi,bj)-salt(i,j,k,bi,bj))
217 & )
218 ENDDO
219 ENDDO
220 ENDIF
221 C Net vertical flux
222 DO j=jMin,jMax
223 DO i=iMin,iMax
224 fVerS(i,j,kUp) = ( afFacS*af(i,j)+ dfFacS*df(i,j) )*maskUp(i,j)
225 ENDDO
226 ENDDO
227 IF ( TOP_LAYER ) THEN
228 DO j=jMin,jMax
229 DO i=iMin,iMax
230 fVerS(i,j,kUp) = afFacS*af(i,j)*freeSurfFac
231 ENDDO
232 ENDDO
233 ENDIF
234
235 C-- Tendency is minus divergence of the fluxes.
236 C Note. Tendency terms will only be correct for range
237 C i=iMin+1:iMax-1, j=jMin+1:jMax-1. Edge points
238 C will contain valid floating point numbers but
239 C they are not algorithmically correct. These points
240 C are not used.
241 DO j=jMin,jMax
242 DO i=iMin,iMax
243 C & -_rhFacC(i,j,k,bi,bj)*rdzF(k)*_rdxF(i,j,bi,bj)*_rdyF(i,j,bi,bj)
244 C & -_rhFacC(i,j,k,bi,bj)*rdzF(k)/_zA(i,j,bi,bj)
245 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)
246 #define _rVolS(i,j,k,bi,bj) _rhFacC(i,j,k,bi,bj)*rdzF(k)/_zA(i,j,bi,bj)
247 gS(i,j,k,bi,bj)=
248 & -_rVolS(i,j,k,bi,bj)
249 & *(
250 & +( fZon(i+1,j)-fZon(i,j) )
251 & +( fMer(i,j+1)-fMer(i,j) )
252 & +( fVerS(i,j,kUp)-fVerS(i,j,kDown) )
253 & )
254 ENDDO
255 ENDDO
256
257 C-- External P-E forcing term(s)
258 C o Surface relaxation term
259 IF ( TOP_LAYER ) THEN
260 DO j=jMin,jMax
261 DO i=iMin,iMax
262 gS(i,j,k,bi,bj)=gS(i,j,k,bi,bj)
263 & +maskC(i,j)*(
264 & -lambdaSaltClimRelax*(salt(i,j,k,bi,bj)-SSS(i,j,bi,bj))
265 & +EmPmR(i,j,bi,bj) )
266 ENDDO
267 ENDDO
268 ENDIF
269
270
271 RETURN
272 END

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