C $Header: /home/ubuntu/mnt/e9_copy/MITgcm/pkg/generic_advdiff/gad_grad_y.F,v 1.1 2001/05/30 19:34:48 adcroft Exp $
C $Name:  $

#include "GAD_OPTIONS.h"

      SUBROUTINE GAD_GRAD_Y( 
     I           bi,bj,k,
     I           yA,
     I           tracer,
     O           dTdy,
     I           myThid )
      IMPLICIT NONE

C     == GLobal variables ==
#include "SIZE.h"
#include "GRID.h"

C     == Routine arguments ==
      INTEGER bi,bj,k
      _RS yA    (1-OLx:sNx+OLx,1-OLy:sNy+OLy)
      _RL tracer(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
      _RL dTdy  (1-OLx:sNx+OLx,1-OLy:sNy+OLy)
      INTEGER myThid

C     == Local variables ==
      INTEGER i,j

C     o Meridional tracer gradient
      DO i=1-Olx,sNx+Olx
       dTdy(I,1-Oly)=0.
      ENDDO
      DO j=1-Oly+1,sNy+Oly
       DO i=1-Olx,sNx+Olx
        dTdy(i,j) = _recip_dyC(i,j,bi,bj)*yA(i,j)
     &               *(tracer(i,j)-tracer(i,j-1))
#ifdef ISOTROPIC_COS_SCALING
#ifdef COSINEMETH_III
     &   *sqCosFacV(j,bi,bj)
#endif
#endif
       ENDDO
      ENDDO

      RETURN
      END