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C $Header: /u/gcmpack/MITgcm/pkg/generic_advdiff/gad_del2.F,v 1.2 2001/09/20 20:07:06 adcroft Exp $ |
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C $Name: $ |
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|
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#include "GAD_OPTIONS.h" |
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|
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CBOP |
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C !ROUTINE: GAD_DEL2 |
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|
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C !INTERFACE: ========================================================== |
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SUBROUTINE GAD_DEL2( |
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I bi,bj,k, |
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I dTdx,dTdy, |
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O del2, |
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I myThid ) |
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|
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C !DESCRIPTION: |
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C Calculates the horizontal Laplacian of a tracer: |
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C \begin{equation*} |
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C \nabla^2 \theta = \partial_{xx} \theta + \partial_{yy} \theta |
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C \end{equation*} |
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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 "GRID.h" |
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|
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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 dTx :: zonal tracer gradient |
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C dTy :: meridional tracer gradient |
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C myThid :: thread number |
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INTEGER bi,bj,k |
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_RL dTdx(1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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_RL dTdy(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 del2 :: Laplacian of tracer |
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_RL del2(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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c _RL dfx(1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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c _RL dfy(1-OLx:sNx+OLx,1-OLy:sNy+OLy) |
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CEOP |
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|
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C-- Initialise to zero. |
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DO j=1-Oly,sNy+Oly |
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DO i=1-Olx,sNx+Olx |
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del2(i,j)= 0. _d 0 |
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ENDDO |
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ENDDO |
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|
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C Difference of zonal fluxes & meridional fluxes |
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C and divide by grid-cell volume |
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DO j=1-Oly,sNy+Oly-1 |
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DO i=1-Olx,sNx+Olx-1 |
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del2(i,j)=recip_rA(i,j,bi,bj) |
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& *recip_drF(k) |
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& *_recip_hFacC(i,j,k,bi,bj) |
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& *( ( dTdx(i+1,j)-dTdx(i,j) ) |
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& +( dTdy(i,j+1)-dTdy(i,j) ) |
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& ) |
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ENDDO |
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ENDDO |
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|
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RETURN |
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END |