pkg/generic_advdiff/gad_del2.F

C $Header: /u/gcmpack/MITgcm/pkg/generic_advdiff/gad_del2.F,v 1.2 2001/09/20 20:07:06 adcroft Exp $
C $Name:  $

#include "GAD_OPTIONS.h"

CBOP
C !ROUTINE: GAD_DEL2

C !INTERFACE: ==========================================================
      SUBROUTINE GAD_DEL2( 
     I           bi,bj,k,
     I           dTdx,dTdy,
     O           del2,
     I           myThid )

C !DESCRIPTION:
C Calculates the horizontal Laplacian of a tracer:
C \begin{equation*}
C \nabla^2 \theta = \partial_{xx} \theta + \partial_{yy} \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  dTx                  :: zonal tracer gradient
C  dTy                  :: meridional tracer gradient
C  myThid               :: thread number
      INTEGER bi,bj,k
      _RL dTdx(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
      _RL dTdy(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
      INTEGER myThid

C !OUTPUT PARAMETERS: ==================================================
C  del2                 :: Laplacian of tracer
      _RL del2(1-OLx:sNx+OLx,1-OLy:sNy+OLy)

C !LOCAL VARIABLES: ====================================================
C  i,j                  :: loop indices
      INTEGER i,j
c     _RL dfx(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
c     _RL dfy(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
CEOP

C--   Initialise to zero.
      DO j=1-Oly,sNy+Oly
       DO i=1-Olx,sNx+Olx
        del2(i,j)= 0. _d 0
       ENDDO
      ENDDO

C     Difference of zonal fluxes & meridional fluxes
C      and divide by grid-cell volume
      DO j=1-Oly,sNy+Oly-1
       DO i=1-Olx,sNx+Olx-1
        del2(i,j)=recip_rA(i,j,bi,bj)
     &           *recip_drF(k)
     &           *_recip_hFacC(i,j,k,bi,bj)
     &           *( ( dTdx(i+1,j)-dTdx(i,j) )
     &             +( dTdy(i,j+1)-dTdy(i,j) )
     &            )
       ENDDO
      ENDDO

      RETURN
      END
1	C $Header: /u/gcmpack/MITgcm/pkg/generic_advdiff/gad_del2.F,v 1.2 2001/09/20 20:07:06 adcroft Exp $
2	C $Name: $
3
4	#include "GAD_OPTIONS.h"
5
6	CBOP
7	C !ROUTINE: GAD_DEL2
8
9	C !INTERFACE: ==========================================================
10	SUBROUTINE GAD_DEL2(
11	I bi,bj,k,
12	I dTdx,dTdy,
13	O del2,
14	I myThid )
15
16	C !DESCRIPTION:
17	C Calculates the horizontal Laplacian of a tracer:
18	C \begin{equation*}
19	C \nabla^2 \theta = \partial_{xx} \theta + \partial_{yy} \theta
20	C \end{equation*}
21
22	C !USES: ===============================================================
23	IMPLICIT NONE
24	#include "SIZE.h"
25	#include "GRID.h"
26
27	C !INPUT PARAMETERS: ===================================================
28	C bi,bj :: tile indices
29	C k :: vertical level
30	C dTx :: zonal tracer gradient
31	C dTy :: meridional tracer gradient
32	C myThid :: thread number
33	INTEGER bi,bj,k
34	_RL dTdx(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
35	_RL dTdy(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
36	INTEGER myThid
37
38	C !OUTPUT PARAMETERS: ==================================================
39	C del2 :: Laplacian of tracer
40	_RL del2(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
41
42	C !LOCAL VARIABLES: ====================================================
43	C i,j :: loop indices
44	INTEGER i,j
45	c _RL dfx(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
46	c _RL dfy(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
47	CEOP
48
49	C-- Initialise to zero.
50	DO j=1-Oly,sNy+Oly
51	DO i=1-Olx,sNx+Olx
52	del2(i,j)= 0. _d 0
53	ENDDO
54	ENDDO
55
56	C Difference of zonal fluxes & meridional fluxes
57	C and divide by grid-cell volume
58	DO j=1-Oly,sNy+Oly-1
59	DO i=1-Olx,sNx+Olx-1
60	del2(i,j)=recip_rA(i,j,bi,bj)
61	& *recip_drF(k)
62	& *_recip_hFacC(i,j,k,bi,bj)
63	& *( ( dTdx(i+1,j)-dTdx(i,j) )
64	& +( dTdy(i,j+1)-dTdy(i,j) )
65	& )
66	ENDDO
67	ENDDO
68
69	RETURN
70	END