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C $Header: /u/gcmpack/MITgcm/pkg/mom_common/mom_calc_strain.F,v 1.4 2005/10/12 00:58:29 jmc Exp $ |
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C $Name: $ |
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#include "MOM_COMMON_OPTIONS.h" |
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|
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CBOP |
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C !ROUTINE: MOM_CALC_STRAIN |
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C !INTERFACE: ========================================================== |
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SUBROUTINE MOM_CALC_STRAIN( |
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I bi,bj,k, |
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I uFld, vFld, hFacZ, |
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O strain, |
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I myThid ) |
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|
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C !DESCRIPTION: |
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C Calculates the strain of the horizontal flow field (at vorticity points): |
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C \begin{equation*} |
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C D_S = \frac{\Delta y_u}{\Delta x_v} \delta_i \frac{v}{\Delta y_c} |
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C + \frac{\Delta x_v}{\Delta y_u} \delta_j \frac{u}{\Delta x_c} |
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C \end{equation*} |
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C assuming free-slip boundaries. |
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|
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C !USES: =============================================================== |
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IMPLICIT NONE |
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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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C !INPUT PARAMETERS: =================================================== |
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C bi,bj :: tile indices |
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C k :: vertical level |
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C uFld :: zonal flow |
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C vFld :: meridional flow |
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C hFacZ :: open-water thickness at vorticity points |
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C myThid :: thread number |
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INTEGER bi,bj,k |
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_RL uFld(1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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_RL vFld(1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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_RS hFacZ(1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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INTEGER myThid |
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|
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C !OUTPUT PARAMETERS: ================================================== |
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C strain :: strain of horizontal flow |
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_RL strain(1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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|
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C !LOCAL VARIABLES: ==================================================== |
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C i,j :: loop indices |
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INTEGER i,j |
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CEOP |
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|
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DO j=2-OLy,sNy+OLy |
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DO i=2-OLx,sNx+OLx |
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|
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C Strain of horizontal flow field (ignoring lopping factors) |
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strain(i,j)= |
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& ( dyC( i , j ,bi,bj)*vFld( i , j ) |
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& -dyC(i-1, j ,bi,bj)*vFld(i-1, j ) |
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& +dxC( i , j ,bi,bj)*uFld( i , j ) |
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& -dxC( i ,j-1,bi,bj)*uFld( i ,j-1) |
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& )*recip_rAz(i,j,bi,bj)*recip_deepFacC(k) |
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c strain(i,j)= |
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c & dyU(i,j,bi,bj)*recip_dxV(i,j,bi,bj)*( |
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c & vFld( i , j )*recip_dyC( i , j ,bi,bj) |
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c & -vFld(i-1, j )*recip_dyC(i-1, j ,bi,bj) ) |
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c & +dxV(i,j,bi,bj)*recip_dyU(i,j,bi,bj)*( |
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c & +uFld( i , j )*recip_dxC( i , j ,bi,bj) |
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c & -uFld( i ,j-1)*recip_dxC( i ,j-1,bi,bj) ) |
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C Set strain to zero on boundaries (free-slip) |
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C mask is now applied afterwards, outside this S/R. |
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c IF (hFacZ(i,j).EQ.0.) THEN |
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c strain(i,j)=0. |
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c ENDIF |
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ENDDO |
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ENDDO |
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C Special stuff for Cubed Sphere |
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IF (useCubedSphereExchange) THEN |
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c STOP 'S/R MOM_CALC_STRAIN: We should not use strain on the cube!' |
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ENDIF |
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|
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RETURN |
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END |
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