/[MITgcm]/MITgcm/model/src/ini_spherical_polar_grid.F
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Revision 1.10 - (hide annotations) (download)
Fri Nov 6 22:44:47 1998 UTC (25 years, 6 months ago) by cnh
Branch: MAIN
CVS Tags: checkpoint18
Changes since 1.9: +5 -3 lines
Changes to allow for atmospheric integration builds of the code

1 cnh 1.9 C $Header: /u/gcmpack/models/MITgcmUV/model/src/ini_spherical_polar_grid.F,v 1.8 1998/08/22 17:51:08 cnh Exp $
2 cnh 1.1
3 cnh 1.10 #include "CPP_OPTIONS.h"
4 cnh 1.1
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 cnh 1.8 _RL zUpper(Nr), zLower(Nr)
69 cnh 1.1 _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 cnh 1.5 xC0 = thetaMin
85     yC0 = phiMin
86 cnh 1.1 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 cnh 1.10 dxF(I,J,bi,bj) = delX(iG+i-1)*deg2rad
106     & *rSphere*COS(yc(I,J,bi,bj)*deg2rad)
107 cnh 1.1 dyF(I,J,bi,bj) = delY(jG+j-1)*deg2rad*rSphere
108     ENDDO
109     yG = yG + delY(jG+J-1)
110     ENDDO
111     ENDDO
112     ENDDO
113     C Now sync. and get edge regions from other threads and/or processes.
114     C Note: We could just set the overlap regions ourselves here but
115     C exchanging edges is safer and is good practice!
116     _EXCH_XY_R4( xc, myThid )
117     _EXCH_XY_R4( yc, myThid )
118     _EXCH_XY_R4(dxF, myThid )
119     _EXCH_XY_R4(dyF, myThid )
120    
121     C-- Calculate separation between other points
122     C dxG, dyG are separations between cell corners along cell faces.
123     DO bj = myByLo(myThid), myByHi(myThid)
124     DO bi = myBxLo(myThid), myBxHi(myThid)
125     DO J=1,sNy
126     DO I=1,sNx
127     jG = myYGlobalLo + (bj-1)*sNy + J-1
128     iG = myXGlobalLo + (bi-1)*sNx + I-1
129     lat = yc(I,J,bi,bj)-delY(jG) * 0.5 _d 0
130     dxG(I,J,bi,bj) = rSphere*COS(lat*deg2rad)*delX(iG)*deg2rad
131     dyG(I,J,bi,bj) = (dyF(I,J,bi,bj)+dyF(I-1,J,bi,bj))*0.5 _d 0
132     ENDDO
133     ENDDO
134     ENDDO
135     ENDDO
136     _EXCH_XY_R4(dxG, myThid )
137     _EXCH_XY_R4(dyG, myThid )
138     C dxV, dyU are separations between velocity points along cell faces.
139     DO bj = myByLo(myThid), myByHi(myThid)
140     DO bi = myBxLo(myThid), myBxHi(myThid)
141     DO J=1,sNy
142     DO I=1,sNx
143     dxV(I,J,bi,bj) = (dxG(I,J,bi,bj)+dxG(I-1,J,bi,bj))*0.5 _d 0
144     dyU(I,J,bi,bj) = (dyG(I,J,bi,bj)+dyG(I,J-1,bi,bj))*0.5 _d 0
145     ENDDO
146     ENDDO
147     ENDDO
148     ENDDO
149     _EXCH_XY_R4(dxV, myThid )
150     _EXCH_XY_R4(dyU, myThid )
151     C dxC, dyC is separation between cell centers
152     DO bj = myByLo(myThid), myByHi(myThid)
153     DO bi = myBxLo(myThid), myBxHi(myThid)
154     DO J=1,sNy
155     DO I=1,sNx
156     dxC(I,J,bi,bj) = (dxF(I,J,bi,bj)+dxF(I-1,J,bi,bj))*0.5 _d 0
157     dyC(I,J,bi,bj) = (dyF(I,J,bi,bj)+dyF(I,J-1,bi,bj))*0.5 _d 0
158     ENDDO
159     ENDDO
160     ENDDO
161     ENDDO
162     _EXCH_XY_R4(dxC, myThid )
163     _EXCH_XY_R4(dyC, myThid )
164 adcroft 1.6 C Calculate vertical face area and trigonometric terms
165 cnh 1.1 DO bj = myByLo(myThid), myByHi(myThid)
166     DO bi = myBxLo(myThid), myBxHi(myThid)
167     DO J=1,sNy
168     DO I=1,sNx
169     jG = myYGlobalLo + (bj-1)*sNy + J-1
170     latS = yc(i,j,bi,bj)-delY(jG)*0.5 _d 0
171     latN = yc(i,j,bi,bj)+delY(jG)*0.5 _d 0
172 cnh 1.8 rA(I,J,bi,bj) = dyF(I,J,bi,bj)
173 cnh 1.1 & *rSphere*(SIN(latN*deg2rad)-SIN(latS*deg2rad))
174 cnh 1.10 C Area cannot be zero but sin can be if lat if < -90.
175     IF ( rA(I,J,bi,bj) .LT. 0. ) rA(I,J,bi,bj) = -rA(I,J,bi,bj)
176 adcroft 1.6 tanPhiAtU(i,j,bi,bj)=tan(_yC(i,j,bi,bj)*deg2rad)
177     tanPhiAtV(i,j,bi,bj)=tan(latS*deg2rad)
178 cnh 1.1 ENDDO
179     ENDDO
180     ENDDO
181     ENDDO
182 cnh 1.8 _EXCH_XY_R4 (rA , myThid )
183 cnh 1.5 _EXCH_XY_R4 (tanPhiAtU , myThid )
184     _EXCH_XY_R4 (tanPhiAtV , myThid )
185    
186 cnh 1.1 C
187     RETURN
188     END

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