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C $Header: /u/gcmpack/MITgcm/model/src/ini_cartesian_grid.F,v 1.19 2005/07/31 22:07:48 jmc Exp $ |
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C $Name: $ |
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|
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#include "CPP_OPTIONS.h" |
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|
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CBOP |
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C !ROUTINE: INI_CARTESIAN_GRID |
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C !INTERFACE: |
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SUBROUTINE INI_CARTESIAN_GRID( myThid ) |
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C !DESCRIPTION: \bv |
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C *==========================================================* |
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C | SUBROUTINE INI_CARTESIAN_GRID |
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C | o Initialise model coordinate system |
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C *==========================================================* |
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C | The grid arrays, initialised here, are used throughout |
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C | the code in evaluating gradients, integrals and spatial |
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C | avarages. This routine |
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C | is called separately by each thread and initialises only |
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C | the region of the domain it is "responsible" for. |
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C | Notes: |
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C | Two examples are included. One illustrates the |
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C | initialisation of a cartesian grid (this routine). |
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C | The other shows the |
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C | inialisation of a spherical polar grid. Other orthonormal |
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C | grids can be fitted into this design. In this case |
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C | custom metric terms also need adding to account for the |
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C | projections of velocity vectors onto these grids. |
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C | The structure used here also makes it possible to |
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C | implement less regular grid mappings. In particular |
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C | o Schemes which leave out blocks of the domain that are |
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C | all land could be supported. |
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C | o Multi-level schemes such as icosohedral or cubic |
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C | grid projections onto a sphere can also be fitted |
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C | within the strategy we use. |
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C | Both of the above also require modifying the support |
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C | routines that map computational blocks to simulation |
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C | domain blocks. |
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C | Under the cartesian grid mode primitive distances in X |
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C | and Y are in metres. Disktance in Z are in m or Pa |
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C | depending on the vertical gridding mode. |
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C *==========================================================* |
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C \ev |
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|
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C !USES: |
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IMPLICIT NONE |
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C === Global variables === |
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#include "SIZE.h" |
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#include "EEPARAMS.h" |
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#include "PARAMS.h" |
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#include "GRID.h" |
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|
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C !INPUT/OUTPUT PARAMETERS: |
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C == Routine arguments == |
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C myThid - Number of this instance of INI_CARTESIAN_GRID |
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INTEGER myThid |
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|
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C !LOCAL VARIABLES: |
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C == Local variables == |
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INTEGER iG, jG, bi, bj, I, J |
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_RL xG0, yG0 |
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C "Long" real for temporary coordinate calculation |
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C NOTICE the extended range of indices!! |
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_RL xGloc(1-Olx:sNx+Olx+1,1-Oly:sNy+Oly+1) |
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_RL yGloc(1-Olx:sNx+Olx+1,1-Oly:sNy+Oly+1) |
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C These functions return the "global" index with valid values beyond |
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C halo regions |
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INTEGER iGl,jGl |
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iGl(I,bi) = 1+mod(myXGlobalLo-1+(bi-1)*sNx+I+Olx*Nx-1,Nx) |
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jGl(J,bj) = 1+mod(myYGlobalLo-1+(bj-1)*sNy+J+Oly*Ny-1,Ny) |
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CEOP |
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|
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C For each tile ... |
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DO bj = myByLo(myThid), myByHi(myThid) |
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DO bi = myBxLo(myThid), myBxHi(myThid) |
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|
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C-- "Global" index (place holder) |
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jG = myYGlobalLo + (bj-1)*sNy |
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iG = myXGlobalLo + (bi-1)*sNx |
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|
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C-- First find coordinate of tile corner (meaning outer corner of halo) |
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xG0 = 0. |
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C Find the X-coordinate of the outer grid-line of the "real" tile |
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DO i=1, iG-1 |
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xG0 = xG0 + delX(i) |
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ENDDO |
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C Back-step to the outer grid-line of the "halo" region |
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DO i=1, Olx |
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xG0 = xG0 - delX( 1+mod(Olx*Nx-1+iG-i,Nx) ) |
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ENDDO |
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C Find the Y-coordinate of the outer grid-line of the "real" tile |
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yG0 = 0. |
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DO j=1, jG-1 |
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yG0 = yG0 + delY(j) |
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ENDDO |
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C Back-step to the outer grid-line of the "halo" region |
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DO j=1, Oly |
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yG0 = yG0 - delY( 1+mod(Oly*Ny-1+jG-j,Ny) ) |
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ENDDO |
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|
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C-- Calculate coordinates of cell corners for N+1 grid-lines |
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DO J=1-Oly,sNy+Oly +1 |
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xGloc(1-Olx,J) = xG0 |
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DO I=1-Olx,sNx+Olx |
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c xGloc(I+1,J) = xGloc(I,J) + delX(1+mod(Nx-1+iG-1+i,Nx)) |
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xGloc(I+1,J) = xGloc(I,J) + delX( iGl(I,bi) ) |
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ENDDO |
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ENDDO |
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DO I=1-Olx,sNx+Olx +1 |
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yGloc(I,1-Oly) = yG0 |
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DO J=1-Oly,sNy+Oly |
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c yGloc(I,J+1) = yGloc(I,J) + delY(1+mod(Ny-1+jG-1+j,Ny)) |
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yGloc(I,J+1) = yGloc(I,J) + delY( jGl(J,bj) ) |
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ENDDO |
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ENDDO |
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|
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C-- Make a permanent copy of [xGloc,yGloc] in [xG,yG] |
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DO J=1-Oly,sNy+Oly |
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DO I=1-Olx,sNx+Olx |
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xG(I,J,bi,bj) = xGloc(I,J) |
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yG(I,J,bi,bj) = yGloc(I,J) |
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ENDDO |
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ENDDO |
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|
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C-- Calculate [xC,yC], coordinates of cell centers |
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DO J=1-Oly,sNy+Oly |
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DO I=1-Olx,sNx+Olx |
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C by averaging |
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xC(I,J,bi,bj) = 0.25*( |
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& xGloc(I,J)+xGloc(I+1,J)+xGloc(I,J+1)+xGloc(I+1,J+1) ) |
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yC(I,J,bi,bj) = 0.25*( |
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& yGloc(I,J)+yGloc(I+1,J)+yGloc(I,J+1)+yGloc(I+1,J+1) ) |
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ENDDO |
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ENDDO |
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|
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C-- Calculate [dxF,dyF], lengths between cell faces (through center) |
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DO J=1-Oly,sNy+Oly |
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DO I=1-Olx,sNx+Olx |
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dXF(I,J,bi,bj) = delX( iGl(I,bi) ) |
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dYF(I,J,bi,bj) = delY( jGl(J,bj) ) |
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ENDDO |
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ENDDO |
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|
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C-- Calculate [dxG,dyG], lengths along cell boundaries |
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DO J=1-Oly,sNy+Oly |
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DO I=1-Olx,sNx+Olx |
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dXG(I,J,bi,bj) = delX( iGl(I,bi) ) |
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dYG(I,J,bi,bj) = delY( jGl(J,bj) ) |
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ENDDO |
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ENDDO |
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|
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C-- The following arrays are not defined in some parts of the halo |
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C region. We set them to zero here for safety. If they are ever |
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C referred to, especially in the denominator then it is a mistake! |
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DO J=1-Oly,sNy+Oly |
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DO I=1-Olx,sNx+Olx |
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dXC(I,J,bi,bj) = 0. |
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dYC(I,J,bi,bj) = 0. |
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dXV(I,J,bi,bj) = 0. |
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dYU(I,J,bi,bj) = 0. |
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rAw(I,J,bi,bj) = 0. |
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rAs(I,J,bi,bj) = 0. |
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ENDDO |
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ENDDO |
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|
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C-- Calculate [dxC], zonal length between cell centers |
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DO J=1-Oly,sNy+Oly |
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DO I=1-Olx+1,sNx+Olx ! NOTE range |
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dXC(I,J,bi,bj) = 0.5D0*(dXF(I,J,bi,bj)+dXF(I-1,J,bi,bj)) |
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ENDDO |
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ENDDO |
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|
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C-- Calculate [dyC], meridional length between cell centers |
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DO J=1-Oly+1,sNy+Oly ! NOTE range |
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DO I=1-Olx,sNx+Olx |
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dYC(I,J,bi,bj) = 0.5*(dYF(I,J,bi,bj)+dYF(I,J-1,bi,bj)) |
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ENDDO |
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ENDDO |
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|
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C-- Calculate [dxV,dyU], length between velocity points (through corners) |
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DO J=1-Oly+1,sNy+Oly ! NOTE range |
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DO I=1-Olx+1,sNx+Olx ! NOTE range |
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C by averaging (method I) |
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dXV(I,J,bi,bj) = 0.5*(dXG(I,J,bi,bj)+dXG(I-1,J,bi,bj)) |
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dYU(I,J,bi,bj) = 0.5*(dYG(I,J,bi,bj)+dYG(I,J-1,bi,bj)) |
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C by averaging (method II) |
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c dXV(I,J,bi,bj) = 0.5*(dXG(I,J,bi,bj)+dXG(I-1,J,bi,bj)) |
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c dYU(I,J,bi,bj) = 0.5*(dYC(I,J,bi,bj)+dYC(I-1,J,bi,bj)) |
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ENDDO |
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ENDDO |
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|
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C-- Calculate vertical face area |
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DO J=1-Oly,sNy+Oly |
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DO I=1-Olx,sNx+Olx |
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rA (I,J,bi,bj) = dxF(I,J,bi,bj)*dyF(I,J,bi,bj) |
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rAw(I,J,bi,bj) = dxC(I,J,bi,bj)*dyG(I,J,bi,bj) |
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rAs(I,J,bi,bj) = dxG(I,J,bi,bj)*dyC(I,J,bi,bj) |
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rAz(I,J,bi,bj) = dxV(I,J,bi,bj)*dyU(I,J,bi,bj) |
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C-- Set trigonometric terms & grid orientation: |
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tanPhiAtU(I,J,bi,bj) = 0. |
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tanPhiAtV(I,J,bi,bj) = 0. |
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angleCosC(I,J,bi,bj) = 1. |
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angleSinC(I,J,bi,bj) = 0. |
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ENDDO |
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ENDDO |
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|
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C-- Cosine(lat) scaling |
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DO J=1-OLy,sNy+OLy |
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cosFacU(J,bi,bj)=1. |
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cosFacV(J,bi,bj)=1. |
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sqcosFacU(J,bi,bj)=1. |
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sqcosFacV(J,bi,bj)=1. |
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ENDDO |
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|
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ENDDO ! bi |
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ENDDO ! bj |
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|
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C-- Set default (=whole domain) for where relaxation to climatology applies |
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_BEGIN_MASTER(myThid) |
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IF ( latBandClimRelax.EQ.UNSET_RL ) THEN |
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latBandClimRelax = 0. |
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DO j=1,Ny |
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latBandClimRelax = latBandClimRelax + delY(j) |
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ENDDO |
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latBandClimRelax = latBandClimRelax*3. _d 0 |
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ENDIF |
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_END_MASTER(myThid) |
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|
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RETURN |
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END |
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