C $Header: /u/gcmpack/MITgcm/pkg/generic_advdiff/gad_biharm_x.F,v 1.4 2006/12/05 05:26:46 jmc Exp $ C $Name: $ #include "GAD_OPTIONS.h" CBOP C !ROUTINE: GAD_BIHARM_X C !INTERFACE: ========================================================== SUBROUTINE GAD_BIHARM_X( I bi,bj,k, I xA,del2T,diffK4, U dfx, I myThid ) C !DESCRIPTION: C Calculates the zonal flux due to bi-harmonic diffusion of a tracer. C Routine takes the laplacian of the tracer as argument and calculates C the zonal gradient: C \begin{equation*} C F^x_{diff} = \kappa_4 \partial_x \nabla^2 \theta C \end{equation*} C !USES: =============================================================== IMPLICIT NONE #include "SIZE.h" #include "GRID.h" C !INPUT PARAMETERS: =================================================== C bi,bj :: tile indices C k :: vertical level C xA :: area of face at U points C del2T :: Laplacian of tracer C myThid :: thread number INTEGER bi,bj,k _RS xA (1-OLx:sNx+OLx,1-OLy:sNy+OLy) _RL del2T(1-OLx:sNx+OLx,1-OLy:sNy+OLy) _RL diffK4 INTEGER myThid C !OUTPUT PARAMETERS: ================================================== C dfx :: zonal diffusive flux _RL dfx (1-OLx:sNx+OLx,1-OLy:sNy+OLy) C !LOCAL VARIABLES: ==================================================== C i,j :: loop indices INTEGER i,j CEOP C Difference of zonal fluxes ... DO j=1-Oly,sNy+Oly c dfx(1-Olx,j) = 0. DO i=1-Olx+1,sNx+Olx c dfx(i,j) = diffK4*xA(i,j) dfx(i,j) = dfx(i,j) + diffK4*xA(i,j) & *_recip_dxC(i,j,bi,bj)*recip_deepFacC(k) & *(del2T(i,j)-del2T(i-1,j)) #ifdef COSINEMETH_III & *sqCosFacU(j,bi,bj) #else & *cosFacU(j,bi,bj) #endif ENDDO ENDDO RETURN END