model/src/ini_cartesian_grid.F

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 $
C $Name:  $

#include "CPP_OPTIONS.h"

CStartOfInterface
      SUBROUTINE INI_CARTESIAN_GRID( myThid )
C     /==========================================================\
C     | SUBROUTINE INI_CARTESIAN_GRID                            |
C     | o Initialise model coordinate system                     |
C     |==========================================================|
C     | These arrays are used throughout the code in evaluating  |
C     | gradients, integrals and spatial avarages. This routine  |
C     | is called separately by each thread and initialise only  |
C     | the region of the domain it is "responsible" for.        |
C     | Notes:                                                   |
C     | Two examples are included. One illustrates the           |
C     | initialisation of a cartesian grid. The other shows the  |
C     | inialisation of a spherical polar grid. Other orthonormal|
C     | grids can be fitted into this design. In this case       |
C     | custom metric terms also need adding to account for the  |
C     | projections of velocity vectors onto these grids.        |
C     | The structure used here also makes it possible to        |
C     | implement less regular grid mappings. In particular      |
C     | o Schemes which leave out blocks of the domain that are  |
C     |   all land could be supported.                           |
C     | o Multi-level schemes such as icosohedral or cubic       |
C     |   grid projections onto a sphere can also be fitted      |
C     |   within the strategy we use.                            |
C     |   Both of the above also require modifying the support   |
C     |   routines that map computational blocks to simulation   |
C     |   domain blocks.                                         |
C     | Under the cartesian grid mode primitive distances in X   |
C     | and Y are in metres. Disktance in Z are in m or Pa       |
C     | depending on the vertical gridding mode.                 |
C     \==========================================================/
      IMPLICIT NONE

C     === Global variables ===
#include "SIZE.h"
#include "EEPARAMS.h"
#include "PARAMS.h"
#include "GRID.h"

C     == Routine arguments ==
C     myThid -  Number of this instance of INI_CARTESIAN_GRID
      INTEGER myThid
CEndOfInterface

C     == Local variables ==
      INTEGER iG, jG, bi, bj, I,  J
      _RL xG0, yG0

C "Long" real for temporary coordinate calculation
C  NOTICE the extended range of indices!!
      _RL xGloc(1-Olx:sNx+Olx+1,1-Oly:sNy+Oly+1)
      _RL yGloc(1-Olx:sNx+Olx+1,1-Oly:sNy+Oly+1)

C These functions return the "global" index with valid values beyond
C halo regions
      INTEGER iGl,jGl
      iGl(I,bi) = 1+mod(myXGlobalLo-1+(bi-1)*sNx+I+Olx*Nx-1,Nx)
      jGl(J,bj) = 1+mod(myYGlobalLo-1+(bj-1)*sNy+J+Oly*Ny-1,Ny)

C     For each tile ...
      DO bj = myByLo(myThid), myByHi(myThid)
       DO bi = myBxLo(myThid), myBxHi(myThid)

C--     "Global" index (place holder)
        jG = myYGlobalLo + (bj-1)*sNy
        iG = myXGlobalLo + (bi-1)*sNx

C--   First find coordinate of tile corner (meaning outer corner of halo)
        xG0 = 0.
C       Find the X-coordinate of the outer grid-line of the "real" tile
        DO i=1, iG-1
         xG0 = xG0 + delX(i)
        ENDDO
C       Back-step to the outer grid-line of the "halo" region
        DO i=1, Olx
         xG0 = xG0 - delX( 1+mod(Olx*Nx-1+iG-i,Nx) )
        ENDDO
C       Find the Y-coordinate of the outer grid-line of the "real" tile
        yG0 = 0.
        DO j=1, jG-1
         yG0 = yG0 + delY(j)
        ENDDO
C       Back-step to the outer grid-line of the "halo" region
        DO j=1, Oly
         yG0 = yG0 - delY( 1+mod(Oly*Ny-1+jG-j,Ny) )
        ENDDO

C--     Calculate coordinates of cell corners for N+1 grid-lines
        DO J=1-Oly,sNy+Oly +1
         xGloc(1-Olx,J) = xG0
         DO I=1-Olx,sNx+Olx
c         xGloc(I+1,J) = xGloc(I,J) + delX(1+mod(Nx-1+iG-1+i,Nx))
          xGloc(I+1,J) = xGloc(I,J) + delX( iGl(I,bi) )
         ENDDO
        ENDDO
        DO I=1-Olx,sNx+Olx +1
         yGloc(I,1-Oly) = yG0
         DO J=1-Oly,sNy+Oly
c         yGloc(I,J+1) = yGloc(I,J) + delY(1+mod(Ny-1+jG-1+j,Ny))
          yGloc(I,J+1) = yGloc(I,J) + delY( jGl(J,bj) )
         ENDDO
        ENDDO

C--     Make a permanent copy of [xGloc,yGloc] in [xG,yG]
        DO J=1-Oly,sNy+Oly
         DO I=1-Olx,sNx+Olx
          xG(I,J,bi,bj) = xGloc(I,J)
          yG(I,J,bi,bj) = yGloc(I,J)
         ENDDO
        ENDDO

C--     Calculate [xC,yC], coordinates of cell centers
        DO J=1-Oly,sNy+Oly
         DO I=1-Olx,sNx+Olx
C         by averaging
          xC(I,J,bi,bj) = 0.25*(
     &     xGloc(I,J)+xGloc(I+1,J)+xGloc(I,J+1)+xGloc(I+1,J+1) )
          yC(I,J,bi,bj) = 0.25*(
     &     yGloc(I,J)+yGloc(I+1,J)+yGloc(I,J+1)+yGloc(I+1,J+1) )
         ENDDO
        ENDDO

C--     Calculate [dxF,dyF], lengths between cell faces (through center)
        DO J=1-Oly,sNy+Oly
         DO I=1-Olx,sNx+Olx
          dXF(I,J,bi,bj) = delX( iGl(I,bi) )
          dYF(I,J,bi,bj) = delY( jGl(J,bj) )
         ENDDO
        ENDDO

C--     Calculate [dxG,dyG], lengths along cell boundaries
        DO J=1-Oly,sNy+Oly
         DO I=1-Olx,sNx+Olx
          dXG(I,J,bi,bj) = delX( iGl(I,bi) )
          dYG(I,J,bi,bj) = delY( jGl(J,bj) )
         ENDDO
        ENDDO

C--     The following arrays are not defined in some parts of the halo
C       region. We set them to zero here for safety. If they are ever
C       referred to, especially in the denominator then it is a mistake!
        DO J=1-Oly,sNy+Oly
         DO I=1-Olx,sNx+Olx
          dXC(I,J,bi,bj) = 0.
          dYC(I,J,bi,bj) = 0.
          dXV(I,J,bi,bj) = 0.
          dYU(I,J,bi,bj) = 0.
          rAw(I,J,bi,bj) = 0.
          rAs(I,J,bi,bj) = 0.
         ENDDO
        ENDDO

C--     Calculate [dxC], zonal length between cell centers
        DO J=1-Oly,sNy+Oly
         DO I=1-Olx+1,sNx+Olx ! NOTE range
          dXC(I,J,bi,bj) = 0.5D0*(dXF(I,J,bi,bj)+dXF(I-1,J,bi,bj))
         ENDDO
        ENDDO

C--     Calculate [dyC], meridional length between cell centers
        DO J=1-Oly+1,sNy+Oly ! NOTE range
         DO I=1-Olx,sNx+Olx
          dYC(I,J,bi,bj) = 0.5*(dYF(I,J,bi,bj)+dYF(I,J-1,bi,bj))
         ENDDO
        ENDDO

C--     Calculate [dxV,dyU], length between velocity points (through corners)
        DO J=1-Oly+1,sNy+Oly ! NOTE range
         DO I=1-Olx+1,sNx+Olx ! NOTE range
C         by averaging (method I)
          dXV(I,J,bi,bj) = 0.5*(dXG(I,J,bi,bj)+dXG(I-1,J,bi,bj))
          dYU(I,J,bi,bj) = 0.5*(dYG(I,J,bi,bj)+dYG(I,J-1,bi,bj))
C         by averaging (method II)
c         dXV(I,J,bi,bj) = 0.5*(dXG(I,J,bi,bj)+dXG(I-1,J,bi,bj))
c         dYU(I,J,bi,bj) = 0.5*(dYC(I,J,bi,bj)+dYC(I-1,J,bi,bj))
         ENDDO
        ENDDO

C     Calculate vertical face area 
        DO J=1-Oly,sNy+Oly
         DO I=1-Olx,sNx+Olx
          rA (I,J,bi,bj) = dxF(I,J,bi,bj)*dyF(I,J,bi,bj)
          rAw(I,J,bi,bj) = dxC(I,J,bi,bj)*dyG(I,J,bi,bj)
          rAs(I,J,bi,bj) = dxG(I,J,bi,bj)*dyC(I,J,bi,bj)
          rAz(I,J,bi,bj) = dxV(I,J,bi,bj)*dyU(I,J,bi,bj)
          tanPhiAtU(I,J,bi,bj) = 0.
          tanPhiAtV(I,J,bi,bj) = 0.
         ENDDO
        ENDDO

C--     Cosine(lat) scaling
        DO J=1-OLy,sNy+OLy
         cosFacU(J,bi,bj)=1.
         cosFacV(J,bi,bj)=1.
         sqcosFacU(J,bi,bj)=1.
         sqcosFacV(J,bi,bj)=1.
        ENDDO

       ENDDO ! bi
      ENDDO ! bj

      RETURN
      END
1	adcroft	1.16	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	cnh	1.1
4	cnh	1.10	#include "CPP_OPTIONS.h"
5	cnh	1.1
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	adcroft	1.12	IMPLICIT NONE
38	cnh	1.1
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	adcroft	1.16	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+OlxNx-1,Nx)
63			jGl(J,bj) = 1+mod(myYGlobalLo-1+(bj-1)sNy+J+OlyNy-1,Ny)
64
65			C For each tile ...
66	cnh	1.1	DO bj = myByLo(myThid), myByHi(myThid)
67			DO bi = myBxLo(myThid), myBxHi(myThid)
68	adcroft	1.16
69			C-- "Global" index (place holder)
70			jG = myYGlobalLo + (bj-1)*sNy
71	cnh	1.1	iG = myXGlobalLo + (bi-1)*sNx
72
73	adcroft	1.16	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	cnh	1.1	ENDDO
163			ENDDO
164	adcroft	1.16
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	cnh	1.1	ENDDO
170			ENDDO
171	adcroft	1.16
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	cnh	1.1	ENDDO
182			ENDDO
183	adcroft	1.16
184	cnh	1.1	C Calculate vertical face area
185	adcroft	1.16	DO J=1-Oly,sNy+Oly
186			DO I=1-Olx,sNx+Olx
187	adcroft	1.11	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	adcroft	1.14	rAz(I,J,bi,bj) = dxV(I,J,bi,bj)*dyU(I,J,bi,bj)
191	adcroft	1.16	tanPhiAtU(I,J,bi,bj) = 0.
192			tanPhiAtV(I,J,bi,bj) = 0.
193	cnh	1.6	ENDDO
194			ENDDO
195	cnh	1.1
196	adcroft	1.16	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	cnh	1.1	RETURN
208			END