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

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Revision 1.2 - (show annotations) (download)
Sun Jul 31 22:07:48 2005 UTC (18 years, 10 months ago) by jmc
Branch: MAIN
CVS Tags: checkpoint57t_post, checkpoint57s_post, checkpoint57v_post, checkpoint57r_post, checkpoint57w_post, checkpoint57p_post, checkpint57u_post, checkpoint57q_post
Changes since 1.1: +12 -1 lines
reading of delXfile & delYfile moved from ini_parms.F to ini_grid.F
(ini_parms.F is shorter ; allows later to read from netcdf files)

1 C $Header: /u/gcmpack/MITgcm/model/src/ini_cylinder_grid.F,v 1.1 2005/07/13 00:34:39 jmc Exp $
2 C $Name: $
3
4 #include "CPP_OPTIONS.h"
5
6 CBOP
7 C !ROUTINE: INI_CYLINDER_GRID
8 C !INTERFACE:
9 SUBROUTINE INI_CYLINDER_GRID( myThid )
10 C !DESCRIPTION: \bv
11 C /==========================================================\
12 C | SUBROUTINE INI_CYLINDER_GRID
13 C | o Initialise model coordinate system arrays |
14 C |==========================================================|
15 C | These arrays are used throughout the code in evaluating |
16 C | gradients, integrals and spatial avarages. This routine |
17 C | is called separately by each thread and initialise only |
18 C | the region of the domain it is "responsible" for. |
19 C | Under the spherical polar grid mode primitive distances |
20 C | in X is in degrees and Y in meters. |
21 C | Distance in Z are in m or Pa |
22 C | depending on the vertical gridding mode. |
23 C \==========================================================/
24 C \ev
25
26 C !USES:
27 IMPLICIT NONE
28 C === Global variables ===
29 #include "SIZE.h"
30 #include "EEPARAMS.h"
31 #include "PARAMS.h"
32 #include "GRID.h"
33
34 C !INPUT/OUTPUT PARAMETERS:
35 C == Routine arguments ==
36 C myThid - Number of this instance of INI_CYLINDER
37 INTEGER myThid
38 CEndOfInterface
39
40 C !LOCAL VARIABLES:
41 C == Local variables ==
42 C xG, yG - Global coordinate location.
43 C xBase - South-west corner location for process.
44 C yBase
45 C zUpper - Work arrays for upper and lower
46 C zLower cell-face heights.
47 C phi - Temporary scalar
48 C iG, jG - Global coordinate index. Usually used to hold
49 C the south-west global coordinate of a tile.
50 C bi,bj - Loop counters
51 C zUpper - Temporary arrays holding z coordinates of
52 C zLower upper and lower faces.
53 C xBase - Lower coordinate for this threads cells
54 C yBase
55 C lat, latN, - Temporary variables used to hold latitude
56 C latS values.
57 C I,J,K
58 INTEGER iG, jG
59 INTEGER bi, bj
60 INTEGER I, J
61 _RL dtheta, thisRad, xG0, yG0
62 CHARACTER*(MAX_LEN_MBUF) msgBuf
63
64 C "Long" real for temporary coordinate calculation
65 C NOTICE the extended range of indices!!
66 _RL xGloc(1-Olx:sNx+Olx+1,1-Oly:sNy+Oly+1)
67 _RL yGloc(1-Olx:sNx+Olx+1,1-Oly:sNy+Oly+1)
68
69 C The functions iGl, jGl return the "global" index with valid values beyond
70 C halo regions
71 C cnh wrote:
72 C > I dont understand why we would ever have to multiply the
73 C > overlap by the total domain size e.g
74 C > OLx*Nx, OLy*Ny.
75 C > Can anybody explain? Lines are in ini_spherical_polar_grid.F.
76 C > Surprised the code works if its wrong, so I am puzzled.
77 C jmc replied:
78 C Yes, I can explain this since I put this modification to work
79 C with small domain (where Oly > Ny, as for instance, zonal-average
80 C case):
81 C This has no effect on the acuracy of the evaluation of iGl(I,bi)
82 C and jGl(J,bj) since we take mod(a+OLx*Nx,Nx) and mod(b+OLy*Ny,Ny).
83 C But in case a or b is negative, then the FORTRAN function "mod"
84 C does not return the matematical value of the "modulus" function,
85 C and this is not good for your purpose.
86 C This is why I add +OLx*Nx and +OLy*Ny to be sure that the 1rst
87 C argument of the mod function is positive.
88 INTEGER iGl,jGl
89 iGl(I,bi) = 1+mod(myXGlobalLo-1+(bi-1)*sNx+I+Olx*Nx-1,Nx)
90 jGl(J,bj) = 1+mod(myYGlobalLo-1+(bj-1)*sNy+J+Oly*Ny-1,Ny)
91 CEOP
92
93
94 C For each tile ...
95 DO bj = myByLo(myThid), myByHi(myThid)
96 DO bi = myBxLo(myThid), myBxHi(myThid)
97
98 C-- "Global" index (place holder)
99 jG = myYGlobalLo + (bj-1)*sNy
100 iG = myXGlobalLo + (bi-1)*sNx
101
102 C-- First find coordinate of tile corner (meaning outer corner of halo)
103 xG0 = thetaMin
104 C Find the X-coordinate of the outer grid-line of the "real" tile
105 DO i=1, iG-1
106 xG0 = xG0 + delX(i)
107 ENDDO
108 C Back-step to the outer grid-line of the "halo" region
109 DO i=1, Olx
110 xG0 = xG0 - delX( 1+mod(Olx*Nx-1+iG-i,Nx) )
111 ENDDO
112 C Find the Y-coordinate of the outer grid-line of the "real" tile
113 yG0 = 0
114 DO j=1, jG-1
115 yG0 = yG0 + delY(j)
116 ENDDO
117 C Back-step to the outer grid-line of the "halo" region
118 DO j=1, Oly
119 yG0 = yG0 - delY( 1+mod(Oly*Ny-1+jG-j,Ny) )
120 ENDDO
121
122 C-- Calculate coordinates of cell corners for N+1 grid-lines
123 DO J=1-Oly,sNy+Oly +1
124 xGloc(1-Olx,J) = xG0
125 DO I=1-Olx,sNx+Olx
126 xGloc(I+1,J) = xGloc(I,J) + delX( iGl(I,bi) )
127 ENDDO
128 ENDDO
129 DO I=1-Olx,sNx+Olx +1
130 yGloc(I,1-Oly) = yG0
131 DO J=1-Oly,sNy+Oly
132 yGloc(I,J+1) = yGloc(I,J) + delY( jGl(J,bj) )
133 ENDDO
134 ENDDO
135
136 C-- Make a permanent copy of [xGloc,yGloc] in [xG,yG]
137 DO J=1-Oly,sNy+Oly
138 DO I=1-Olx,sNx+Olx
139 xG(I,J,bi,bj) = xGloc(I,J)
140 yG(I,J,bi,bj) = yGloc(I,J)
141 ENDDO
142 ENDDO
143
144 C-- Calculate [xC,yC], coordinates of cell centers
145 DO J=1-Oly,sNy+Oly
146 DO I=1-Olx,sNx+Olx
147 C by averaging
148 xC(I,J,bi,bj) = 0.25*(
149 & xGloc(I,J)+xGloc(I+1,J)+xGloc(I,J+1)+xGloc(I+1,J+1) )
150 yC(I,J,bi,bj) = 0.25*(
151 & yGloc(I,J)+yGloc(I+1,J)+yGloc(I,J+1)+yGloc(I+1,J+1) )
152 ENDDO
153 ENDDO
154
155 C-- Calculate [dxF,dyF], lengths between cell faces (through center)
156 DO J=1-Oly,sNy+Oly
157 DO I=1-Olx,sNx+Olx
158 thisRad = yC(I,J,bi,bj)
159 dtheta = delX( iGl(I,bi) )
160 dXF(I,J,bi,bj) = thisRad*dtheta*deg2rad
161 dYF(I,J,bi,bj) = delY( jGl(J,bj) )
162 ENDDO
163 ENDDO
164
165 C-- Calculate [dxG,dyG], lengths along cell boundaries
166 DO J=1-Oly,sNy+Oly
167 DO I=1-Olx,sNx+Olx
168 thisRad = 0.5*(yGloc(I,J)+yGloc(I+1,J))
169 dtheta = delX( iGl(I,bi) )
170 dXG(I,J,bi,bj) = thisRad*dtheta*deg2rad
171 dYG(I,J,bi,bj) = delY( jGl(J,bj) )
172 ENDDO
173 ENDDO
174
175 C-- The following arrays are not defined in some parts of the halo
176 C region. We set them to zero here for safety. If they are ever
177 C referred to, especially in the denominator then it is a mistake!
178 DO J=1-Oly,sNy+Oly
179 DO I=1-Olx,sNx+Olx
180 dXC(I,J,bi,bj) = 0.
181 dYC(I,J,bi,bj) = 0.
182 dXV(I,J,bi,bj) = 0.
183 dYU(I,J,bi,bj) = 0.
184 rAw(I,J,bi,bj) = 0.
185 rAs(I,J,bi,bj) = 0.
186 ENDDO
187 ENDDO
188
189 C-- Calculate [dxC], zonal length between cell centers
190 DO J=1-Oly,sNy+Oly
191 DO I=1-Olx+1,sNx+Olx ! NOTE range
192 C by averaging
193 dXC(I,J,bi,bj) = 0.5D0*(dXF(I,J,bi,bj)+dXF(I-1,J,bi,bj))
194 ENDDO
195 ENDDO
196
197 C-- Calculate [dyC], meridional length between cell centers
198 DO J=1-Oly+1,sNy+Oly ! NOTE range
199 DO I=1-Olx,sNx+Olx
200 C by averaging
201 dYC(I,J,bi,bj) = 0.5*(dYF(I,J,bi,bj)+dYF(I,J-1,bi,bj))
202 ENDDO
203 ENDDO
204
205 C-- Calculate [dxV,dyU], length between velocity points (through corners)
206 DO J=1-Oly+1,sNy+Oly ! NOTE range
207 DO I=1-Olx+1,sNx+Olx ! NOTE range
208 C by averaging (method I)
209 dXV(I,J,bi,bj) = 0.5*(dXG(I,J,bi,bj)+dXG(I-1,J,bi,bj))
210 dYU(I,J,bi,bj) = 0.5*(dYG(I,J,bi,bj)+dYG(I,J-1,bi,bj))
211 ENDDO
212 ENDDO
213
214
215
216 C-- Calculate vertical face area
217 DO J=1-Oly,sNy+Oly
218 DO I=1-Olx,sNx+Olx
219 C- All r(dr)(dtheta)
220 rA (I,J,bi,bj) = dxF(I,J,bi,bj)*dyF(I,J,bi,bj)
221 rAw(I,J,bi,bj) = dxC(I,J,bi,bj)*dyG(I,J,bi,bj)
222 rAs(I,J,bi,bj) = dxG(I,J,bi,bj)*dyC(I,J,bi,bj)
223 rAz(I,J,bi,bj) = dxV(I,J,bi,bj)*dyU(I,J,bi,bj)
224 C-- Set trigonometric terms & grid orientation:
225 tanPhiAtU(I,J,bi,bj) = 0.
226 tanPhiAtV(I,J,bi,bj) = 0.
227 angleCosC(I,J,bi,bj) = 1.
228 angleSinC(I,J,bi,bj) = 0.
229 ENDDO
230 ENDDO
231
232 C-- Cosine(lat) scaling
233 DO J=1-OLy,sNy+OLy
234 cosFacU(J,bi,bj)=1.
235 cosFacV(J,bi,bj)=1.
236 sqcosFacU(J,bi,bj)=1.
237 sqcosFacV(J,bi,bj)=1.
238 ENDDO
239
240 ENDDO ! bi
241 ENDDO ! bj
242
243 C-- Set default (=whole domain) for where relaxation to climatology applies
244 IF ( latBandClimRelax.EQ.UNSET_RL ) THEN
245 _BEGIN_MASTER(myThid)
246 latBandClimRelax = 0.
247 DO j=1,Ny
248 latBandClimRelax = latBandClimRelax + delY(j)
249 ENDDO
250 latBandClimRelax = latBandClimRelax*3. _d 0
251 _END_MASTER(myThid)
252 ENDIF
253
254 RETURN
255 END

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