C $Header: /u/gcmpack/MITgcm/pkg/mom_fluxform/mom_v_del2v.F,v 1.10 2014/02/09 18:51:46 jmc Exp $
C $Name:  $

#include "MOM_FLUXFORM_OPTIONS.h"

CBOP
C !ROUTINE: MOM_V_DEL2V

C !INTERFACE: ==========================================================
      SUBROUTINE MOM_V_DEL2V(
     I        bi, bj, k,
     I        vFld, hFacZ, h0FacZ,
     O        del2v,
     I        myThid )

C !DESCRIPTION:
C Calculates the Laplacian of meridional flow

C !USES: ===============================================================
      IMPLICIT NONE
#include "SIZE.h"
#include "EEPARAMS.h"
#include "PARAMS.h"
#include "GRID.h"
#include "SURFACE.h"

C !INPUT PARAMETERS: ===================================================
C  bi,bj                :: tile indices
C  k                    :: vertical level
C  vFld                 :: meridional flow
C  hFacZ                :: fractional thickness at vorticity points
C  h0FacZ               :: fixed fractional thickness at vorticity points
C  myThid               :: my Thread Id number
      INTEGER bi, bj, k
      _RL vFld  (1-OLx:sNx+OLx,1-OLy:sNy+OLy)
      _RS hFacZ (1-OLx:sNx+OLx,1-OLy:sNy+OLy)
      _RS h0FacZ(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
      INTEGER myThid
C !OUTPUT PARAMETERS: ==================================================
C  del2v                :: Laplacian
      _RL del2v(1-OLx:sNx+OLx,1-OLy:sNy+OLy)

C !LOCAL VARIABLES: ====================================================
C  i,j                  :: loop indices
      INTEGER I,J
      _RL fZon(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
      _RL fMer(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
      _RS hFacZClosedE, hFacZClosedW
CEOP

C     Zonal flux d/dx V
      DO j=1-OLy+1,sNy+OLy-1
       DO i=1-OLx+1,sNx+OLx
        fZon(i,j) = drF(k)*hFacZ(i,j)
     &   *_dyU(i,j,bi,bj)
     &   *_recip_dxV(i,j,bi,bj)
     &   *(vFld(i,j)-vFld(i-1,j))
#ifdef COSINEMETH_III
     &   *sqCosFacV(J,bi,bj)
#endif
c    &   *deepFacC(k)        ! dyU scaling factor
c    &   *recip_deepFacC(k)  ! recip_dxV scaling factor
       ENDDO
      ENDDO

C     Meridional flux d/dy V
      DO j=1-OLy,sNy+OLy-1
       DO i=1-OLx+1,sNx+OLx-1
        fMer(i,j) = drF(k)*_hFacC(i,j,k,bi,bj)
     &   *_dxF(i,j,bi,bj)
     &   *_recip_dyF(i,j,bi,bj)
     &   *(vFld(i,j+1)-vFld(i,j))
#if (defined (ISOTROPIC_COS_SCALING) && defined (COSINEMETH_III))
     &   *sqCosFacU(J,bi,bj)
#endif
#ifdef ALLOW_OBCS
     &   *maskInC(i,j,bi,bj)
#endif
c    &   *deepFacC(k)        ! dxF scaling factor
c    &   *recip_deepFacC(k)  ! recip_dyF scaling factor
       ENDDO
      ENDDO

C     del^2 V
      DO j=1-OLy+1,sNy+OLy-1
       DO i=1-OLx+1,sNx+OLx-1
        del2v(i,j) =
     &   recip_drF(k)*_recip_hFacS(i,j,k,bi,bj)
     &  *recip_rAs(i,j,bi,bj)*recip_deepFac2C(k)
     &  *( fZon(i+1,j)    - fZon(i, j )
     &    +fMer( i ,j)    - fMer(i,j-1)
     &   )*_maskS(i,j,k,bi,bj)
#ifdef ALLOW_OBCS
     &    *maskInS(i,j,bi,bj)
#endif
       ENDDO
      ENDDO

      IF (no_slip_sides) THEN
C-- No-slip BCs impose a drag at walls...
       DO j=1-OLy+1,sNy+OLy-1
        DO i=1-OLx+1,sNx+OLx-1
#ifdef NONLIN_FRSURF
         hFacZClosedW = h0FacS(i,j,k,bi,bj) - h0FacZ(i,j)
         hFacZClosedE = h0FacS(i,j,k,bi,bj) - h0FacZ(i+1,j)
#else
         hFacZClosedW = _hFacS(i,j,k,bi,bj) - h0FacZ(i,j)
         hFacZClosedE = _hFacS(i,j,k,bi,bj) - h0FacZ(i+1,j)
#endif
         del2v(i,j) = del2v(i,j)
     &    -_recip_hFacS(i,j,k,bi,bj)
     &       *recip_rAs(i,j,bi,bj)*recip_deepFac2C(k)
     &       *( hFacZClosedW*dyU( i ,j,bi,bj)
     &                      *_recip_dxV( i ,j,bi,bj)
     &         +hFacZClosedE*dyU(i+1,j,bi,bj)
     &                      *_recip_dxV(i+1,j,bi,bj)
     &        )*vFld(i,j)*sideDragFactor
     &         *_maskS(i,j,k,bi,bj)
        ENDDO
       ENDDO
      ENDIF

      RETURN
      END