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

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Revision 1.7 - (show annotations) (download)
Thu Jul 2 14:16:24 1998 UTC (25 years, 10 months ago) by adcroft
Branch: MAIN
CVS Tags: checkpoint11, checkpoint13, checkpoint12, branch-point-rdot
Branch point for: branch-rdot
Changes since 1.6: +1 -63 lines
Re-arrangment of initialisation:
 o ini_grid is now called first and it sets up *only* the grid and
   coordinate system.
 o ini_depths then reads topography are can set it as a function of xC, yC.
 o ini_masks_etc then derives everything else (masks, lopping factors and
   recipricols).
This tidy-up is in preparation for the rDot transformation...(tense pause)!

1 C $Header: /u/gcmpack/models/MITgcmUV/model/src/ini_spherical_polar_grid.F,v 1.6 1998/06/22 15:26:25 adcroft Exp $
2
3 #include "CPP_EEOPTIONS.h"
4
5 CStartOfInterface
6 SUBROUTINE INI_SPHERICAL_POLAR_GRID( myThid )
7 C /==========================================================\
8 C | SUBROUTINE INI_SPHERICAL_POLAR_GRID |
9 C | o Initialise model coordinate system |
10 C |==========================================================|
11 C | These arrays are used throughout the code in evaluating |
12 C | gradients, integrals and spatial avarages. This routine |
13 C | is called separately by each thread and initialise only |
14 C | the region of the domain it is "responsible" for. |
15 C | Notes: |
16 C | Two examples are included. One illustrates the |
17 C | initialisation of a cartesian grid. The other shows the |
18 C | inialisation of a spherical polar grid. Other orthonormal|
19 C | grids can be fitted into this design. In this case |
20 C | custom metric terms also need adding to account for the |
21 C | projections of velocity vectors onto these grids. |
22 C | The structure used here also makes it possible to |
23 C | implement less regular grid mappings. In particular |
24 C | o Schemes which leave out blocks of the domain that are |
25 C | all land could be supported. |
26 C | o Multi-level schemes such as icosohedral or cubic |
27 C | grid projections onto a sphere can also be fitted |
28 C | within the strategy we use. |
29 C | Both of the above also require modifying the support |
30 C | routines that map computational blocks to simulation |
31 C | domain blocks. |
32 C | Under the spherical polar grid mode primitive distances |
33 C | in X and Y are in degrees. Distance in Z are in m or Pa |
34 C | depending on the vertical gridding mode. |
35 C \==========================================================/
36
37 C === Global variables ===
38 #include "SIZE.h"
39 #include "EEPARAMS.h"
40 #include "PARAMS.h"
41 #include "GRID.h"
42
43 C == Routine arguments ==
44 C myThid - Number of this instance of INI_CARTESIAN_GRID
45 INTEGER myThid
46 CEndOfInterface
47
48 C == Local variables ==
49 C xG, yG - Global coordinate location.
50 C zG
51 C xBase - South-west corner location for process.
52 C yBase
53 C zUpper - Work arrays for upper and lower
54 C zLower cell-face heights.
55 C phi - Temporary scalar
56 C iG, jG - Global coordinate index. Usually used to hold
57 C the south-west global coordinate of a tile.
58 C bi,bj - Loop counters
59 C zUpper - Temporary arrays holding z coordinates of
60 C zLower upper and lower faces.
61 C xBase - Lower coordinate for this threads cells
62 C yBase
63 C lat, latN, - Temporary variables used to hold latitude
64 C latS values.
65 C I,J,K
66 _RL xG, yG, zG
67 _RL phi
68 _RL zUpper(Nz), zLower(Nz)
69 _RL xBase, yBase
70 INTEGER iG, jG
71 INTEGER bi, bj
72 INTEGER I, J, K
73 _RL lat, latS, latN
74
75 C-- Example of inialisation for spherical polar grid
76 C-- First set coordinates of cell centers
77 C This operation is only performed at start up so for more
78 C complex configurations it is usually OK to pass iG, jG to a custom
79 C function and have it return xG and yG.
80 C Set up my local grid first
81 C Note: In the spherical polar case delX and delY are given in
82 C degrees and are relative to some starting latitude and
83 C longitude - phiMin and thetaMin.
84 xC0 = thetaMin
85 yC0 = phiMin
86 DO bj = myByLo(myThid), myByHi(myThid)
87 jG = myYGlobalLo + (bj-1)*sNy
88 DO bi = myBxLo(myThid), myBxHi(myThid)
89 iG = myXGlobalLo + (bi-1)*sNx
90 yBase = phiMin
91 xBase = thetaMin
92 DO i=1,iG-1
93 xBase = xBase + delX(i)
94 ENDDO
95 DO j=1,jG-1
96 yBase = yBase + delY(j)
97 ENDDO
98 yG = yBase
99 DO J=1,sNy
100 xG = xBase
101 DO I=1,sNx
102 xc(I,J,bi,bj) = xG + delX(iG+i-1)*0.5 _d 0
103 yc(I,J,bi,bj) = yG + delY(jG+j-1)*0.5 _d 0
104 xG = xG + delX(iG+I-1)
105 dxF(I,J,bi,bj) = delX(iG+i-1)*deg2rad*rSphere*COS(yc(I,J,bi,bj)*deg2rad)
106 dyF(I,J,bi,bj) = delY(jG+j-1)*deg2rad*rSphere
107 ENDDO
108 yG = yG + delY(jG+J-1)
109 ENDDO
110 ENDDO
111 ENDDO
112 C Now sync. and get edge regions from other threads and/or processes.
113 C Note: We could just set the overlap regions ourselves here but
114 C exchanging edges is safer and is good practice!
115 _EXCH_XY_R4( xc, myThid )
116 _EXCH_XY_R4( yc, myThid )
117 _EXCH_XY_R4(dxF, myThid )
118 _EXCH_XY_R4(dyF, myThid )
119
120 C-- Calculate separation between other points
121 C dxG, dyG are separations between cell corners along cell faces.
122 DO bj = myByLo(myThid), myByHi(myThid)
123 DO bi = myBxLo(myThid), myBxHi(myThid)
124 DO J=1,sNy
125 DO I=1,sNx
126 jG = myYGlobalLo + (bj-1)*sNy + J-1
127 iG = myXGlobalLo + (bi-1)*sNx + I-1
128 lat = yc(I,J,bi,bj)-delY(jG) * 0.5 _d 0
129 dxG(I,J,bi,bj) = rSphere*COS(lat*deg2rad)*delX(iG)*deg2rad
130 dyG(I,J,bi,bj) = (dyF(I,J,bi,bj)+dyF(I-1,J,bi,bj))*0.5 _d 0
131 ENDDO
132 ENDDO
133 ENDDO
134 ENDDO
135 _EXCH_XY_R4(dxG, myThid )
136 _EXCH_XY_R4(dyG, myThid )
137 C dxV, dyU are separations between velocity points along cell faces.
138 DO bj = myByLo(myThid), myByHi(myThid)
139 DO bi = myBxLo(myThid), myBxHi(myThid)
140 DO J=1,sNy
141 DO I=1,sNx
142 dxV(I,J,bi,bj) = (dxG(I,J,bi,bj)+dxG(I-1,J,bi,bj))*0.5 _d 0
143 dyU(I,J,bi,bj) = (dyG(I,J,bi,bj)+dyG(I,J-1,bi,bj))*0.5 _d 0
144 ENDDO
145 ENDDO
146 ENDDO
147 ENDDO
148 _EXCH_XY_R4(dxV, myThid )
149 _EXCH_XY_R4(dyU, myThid )
150 C dxC, dyC is separation between cell centers
151 DO bj = myByLo(myThid), myByHi(myThid)
152 DO bi = myBxLo(myThid), myBxHi(myThid)
153 DO J=1,sNy
154 DO I=1,sNx
155 dxC(I,J,bi,bj) = (dxF(I,J,bi,bj)+dxF(I-1,J,bi,bj))*0.5 _d 0
156 dyC(I,J,bi,bj) = (dyF(I,J,bi,bj)+dyF(I,J-1,bi,bj))*0.5 _d 0
157 ENDDO
158 ENDDO
159 ENDDO
160 ENDDO
161 _EXCH_XY_R4(dxC, myThid )
162 _EXCH_XY_R4(dyC, myThid )
163 C Calculate vertical face area and trigonometric terms
164 DO bj = myByLo(myThid), myByHi(myThid)
165 DO bi = myBxLo(myThid), myBxHi(myThid)
166 DO J=1,sNy
167 DO I=1,sNx
168 jG = myYGlobalLo + (bj-1)*sNy + J-1
169 latS = yc(i,j,bi,bj)-delY(jG)*0.5 _d 0
170 latN = yc(i,j,bi,bj)+delY(jG)*0.5 _d 0
171 zA(I,J,bi,bj) = dyF(I,J,bi,bj)
172 & *rSphere*(SIN(latN*deg2rad)-SIN(latS*deg2rad))
173 tanPhiAtU(i,j,bi,bj)=tan(_yC(i,j,bi,bj)*deg2rad)
174 tanPhiAtV(i,j,bi,bj)=tan(latS*deg2rad)
175 ENDDO
176 ENDDO
177 ENDDO
178 ENDDO
179 _EXCH_XY_R4 (zA , myThid )
180 _EXCH_XY_R4 (tanPhiAtU , myThid )
181 _EXCH_XY_R4 (tanPhiAtV , myThid )
182
183 C
184 RETURN
185 END

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