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

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Revision 1.16 - (show annotations) (download)
Tue May 29 14:01:37 2001 UTC (23 years ago) by adcroft
Branch: MAIN
CVS Tags: checkpoint40pre3, checkpoint40pre1, checkpoint40pre7, checkpoint40pre6, checkpoint40pre9, checkpoint40pre8, checkpoint40pre2, checkpoint40pre4, checkpoint40pre5, checkpoint40
Changes since 1.15: +140 -110 lines
Merge from branch pre38:
 o essential mods for cubed sphere
 o debugged atmosphere, dynamcis + physics (aim)
 o new packages (mom_vecinv, mom_fluxform, ...)

1 C $Header: /u/gcmpack/models/MITgcmUV/model/src/ini_cartesian_grid.F,v 1.15.2.2 2001/03/16 17:19:13 adcroft Exp $
2 C $Name: $
3
4 #include "CPP_OPTIONS.h"
5
6 CStartOfInterface
7 SUBROUTINE INI_CARTESIAN_GRID( myThid )
8 C /==========================================================\
9 C | SUBROUTINE INI_CARTESIAN_GRID |
10 C | o Initialise model coordinate system |
11 C |==========================================================|
12 C | These arrays are used throughout the code in evaluating |
13 C | gradients, integrals and spatial avarages. This routine |
14 C | is called separately by each thread and initialise only |
15 C | the region of the domain it is "responsible" for. |
16 C | Notes: |
17 C | Two examples are included. One illustrates the |
18 C | initialisation of a cartesian grid. The other shows the |
19 C | inialisation of a spherical polar grid. Other orthonormal|
20 C | grids can be fitted into this design. In this case |
21 C | custom metric terms also need adding to account for the |
22 C | projections of velocity vectors onto these grids. |
23 C | The structure used here also makes it possible to |
24 C | implement less regular grid mappings. In particular |
25 C | o Schemes which leave out blocks of the domain that are |
26 C | all land could be supported. |
27 C | o Multi-level schemes such as icosohedral or cubic |
28 C | grid projections onto a sphere can also be fitted |
29 C | within the strategy we use. |
30 C | Both of the above also require modifying the support |
31 C | routines that map computational blocks to simulation |
32 C | domain blocks. |
33 C | Under the cartesian grid mode primitive distances in X |
34 C | and Y are in metres. Disktance in Z are in m or Pa |
35 C | depending on the vertical gridding mode. |
36 C \==========================================================/
37 IMPLICIT NONE
38
39 C === Global variables ===
40 #include "SIZE.h"
41 #include "EEPARAMS.h"
42 #include "PARAMS.h"
43 #include "GRID.h"
44
45 C == Routine arguments ==
46 C myThid - Number of this instance of INI_CARTESIAN_GRID
47 INTEGER myThid
48 CEndOfInterface
49
50 C == Local variables ==
51 INTEGER iG, jG, bi, bj, I, J
52 _RL xG0, yG0
53
54 C "Long" real for temporary coordinate calculation
55 C NOTICE the extended range of indices!!
56 _RL xGloc(1-Olx:sNx+Olx+1,1-Oly:sNy+Oly+1)
57 _RL yGloc(1-Olx:sNx+Olx+1,1-Oly:sNy+Oly+1)
58
59 C These functions return the "global" index with valid values beyond
60 C halo regions
61 INTEGER iGl,jGl
62 iGl(I,bi) = 1+mod(myXGlobalLo-1+(bi-1)*sNx+I+Olx*Nx-1,Nx)
63 jGl(J,bj) = 1+mod(myYGlobalLo-1+(bj-1)*sNy+J+Oly*Ny-1,Ny)
64
65 C For each tile ...
66 DO bj = myByLo(myThid), myByHi(myThid)
67 DO bi = myBxLo(myThid), myBxHi(myThid)
68
69 C-- "Global" index (place holder)
70 jG = myYGlobalLo + (bj-1)*sNy
71 iG = myXGlobalLo + (bi-1)*sNx
72
73 C-- First find coordinate of tile corner (meaning outer corner of halo)
74 xG0 = 0.
75 C Find the X-coordinate of the outer grid-line of the "real" tile
76 DO i=1, iG-1
77 xG0 = xG0 + delX(i)
78 ENDDO
79 C Back-step to the outer grid-line of the "halo" region
80 DO i=1, Olx
81 xG0 = xG0 - delX( 1+mod(Olx*Nx-1+iG-i,Nx) )
82 ENDDO
83 C Find the Y-coordinate of the outer grid-line of the "real" tile
84 yG0 = 0.
85 DO j=1, jG-1
86 yG0 = yG0 + delY(j)
87 ENDDO
88 C Back-step to the outer grid-line of the "halo" region
89 DO j=1, Oly
90 yG0 = yG0 - delY( 1+mod(Oly*Ny-1+jG-j,Ny) )
91 ENDDO
92
93 C-- Calculate coordinates of cell corners for N+1 grid-lines
94 DO J=1-Oly,sNy+Oly +1
95 xGloc(1-Olx,J) = xG0
96 DO I=1-Olx,sNx+Olx
97 c xGloc(I+1,J) = xGloc(I,J) + delX(1+mod(Nx-1+iG-1+i,Nx))
98 xGloc(I+1,J) = xGloc(I,J) + delX( iGl(I,bi) )
99 ENDDO
100 ENDDO
101 DO I=1-Olx,sNx+Olx +1
102 yGloc(I,1-Oly) = yG0
103 DO J=1-Oly,sNy+Oly
104 c yGloc(I,J+1) = yGloc(I,J) + delY(1+mod(Ny-1+jG-1+j,Ny))
105 yGloc(I,J+1) = yGloc(I,J) + delY( jGl(J,bj) )
106 ENDDO
107 ENDDO
108
109 C-- Make a permanent copy of [xGloc,yGloc] in [xG,yG]
110 DO J=1-Oly,sNy+Oly
111 DO I=1-Olx,sNx+Olx
112 xG(I,J,bi,bj) = xGloc(I,J)
113 yG(I,J,bi,bj) = yGloc(I,J)
114 ENDDO
115 ENDDO
116
117 C-- Calculate [xC,yC], coordinates of cell centers
118 DO J=1-Oly,sNy+Oly
119 DO I=1-Olx,sNx+Olx
120 C by averaging
121 xC(I,J,bi,bj) = 0.25*(
122 & xGloc(I,J)+xGloc(I+1,J)+xGloc(I,J+1)+xGloc(I+1,J+1) )
123 yC(I,J,bi,bj) = 0.25*(
124 & yGloc(I,J)+yGloc(I+1,J)+yGloc(I,J+1)+yGloc(I+1,J+1) )
125 ENDDO
126 ENDDO
127
128 C-- Calculate [dxF,dyF], lengths between cell faces (through center)
129 DO J=1-Oly,sNy+Oly
130 DO I=1-Olx,sNx+Olx
131 dXF(I,J,bi,bj) = delX( iGl(I,bi) )
132 dYF(I,J,bi,bj) = delY( jGl(J,bj) )
133 ENDDO
134 ENDDO
135
136 C-- Calculate [dxG,dyG], lengths along cell boundaries
137 DO J=1-Oly,sNy+Oly
138 DO I=1-Olx,sNx+Olx
139 dXG(I,J,bi,bj) = delX( iGl(I,bi) )
140 dYG(I,J,bi,bj) = delY( jGl(J,bj) )
141 ENDDO
142 ENDDO
143
144 C-- The following arrays are not defined in some parts of the halo
145 C region. We set them to zero here for safety. If they are ever
146 C referred to, especially in the denominator then it is a mistake!
147 DO J=1-Oly,sNy+Oly
148 DO I=1-Olx,sNx+Olx
149 dXC(I,J,bi,bj) = 0.
150 dYC(I,J,bi,bj) = 0.
151 dXV(I,J,bi,bj) = 0.
152 dYU(I,J,bi,bj) = 0.
153 rAw(I,J,bi,bj) = 0.
154 rAs(I,J,bi,bj) = 0.
155 ENDDO
156 ENDDO
157
158 C-- Calculate [dxC], zonal length between cell centers
159 DO J=1-Oly,sNy+Oly
160 DO I=1-Olx+1,sNx+Olx ! NOTE range
161 dXC(I,J,bi,bj) = 0.5D0*(dXF(I,J,bi,bj)+dXF(I-1,J,bi,bj))
162 ENDDO
163 ENDDO
164
165 C-- Calculate [dyC], meridional length between cell centers
166 DO J=1-Oly+1,sNy+Oly ! NOTE range
167 DO I=1-Olx,sNx+Olx
168 dYC(I,J,bi,bj) = 0.5*(dYF(I,J,bi,bj)+dYF(I,J-1,bi,bj))
169 ENDDO
170 ENDDO
171
172 C-- Calculate [dxV,dyU], length between velocity points (through corners)
173 DO J=1-Oly+1,sNy+Oly ! NOTE range
174 DO I=1-Olx+1,sNx+Olx ! NOTE range
175 C by averaging (method I)
176 dXV(I,J,bi,bj) = 0.5*(dXG(I,J,bi,bj)+dXG(I-1,J,bi,bj))
177 dYU(I,J,bi,bj) = 0.5*(dYG(I,J,bi,bj)+dYG(I,J-1,bi,bj))
178 C by averaging (method II)
179 c dXV(I,J,bi,bj) = 0.5*(dXG(I,J,bi,bj)+dXG(I-1,J,bi,bj))
180 c dYU(I,J,bi,bj) = 0.5*(dYC(I,J,bi,bj)+dYC(I-1,J,bi,bj))
181 ENDDO
182 ENDDO
183
184 C Calculate vertical face area
185 DO J=1-Oly,sNy+Oly
186 DO I=1-Olx,sNx+Olx
187 rA (I,J,bi,bj) = dxF(I,J,bi,bj)*dyF(I,J,bi,bj)
188 rAw(I,J,bi,bj) = dxC(I,J,bi,bj)*dyG(I,J,bi,bj)
189 rAs(I,J,bi,bj) = dxG(I,J,bi,bj)*dyC(I,J,bi,bj)
190 rAz(I,J,bi,bj) = dxV(I,J,bi,bj)*dyU(I,J,bi,bj)
191 tanPhiAtU(I,J,bi,bj) = 0.
192 tanPhiAtV(I,J,bi,bj) = 0.
193 ENDDO
194 ENDDO
195
196 C-- Cosine(lat) scaling
197 DO J=1-OLy,sNy+OLy
198 cosFacU(J,bi,bj)=1.
199 cosFacV(J,bi,bj)=1.
200 sqcosFacU(J,bi,bj)=1.
201 sqcosFacV(J,bi,bj)=1.
202 ENDDO
203
204 ENDDO ! bi
205 ENDDO ! bj
206
207 RETURN
208 END

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