pkg/generic_advdiff/gad_grad_x.F

C $Header: /u/gcmpack/MITgcm/pkg/generic_advdiff/gad_grad_x.F,v 1.6 2006/12/05 05:26:46 jmc Exp $
C $Name:  $

#include "GAD_OPTIONS.h"

CBOP
C !ROUTINE: GAD_GRAD_X

C !INTERFACE: ==========================================================
      SUBROUTINE GAD_GRAD_X(
     I           bi,bj,k,
     I           xA,
     U           tracer,
     O           dTdx,
     I           myThid )

C !DESCRIPTION:
C Calculates the zonal gradient of a tracer: $\partial_x \theta
C = \frac{1}{\Delta x_c} \delta_i \theta$
C and multiplies by the area.

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

C !INPUT PARAMETERS: ===================================================
C  bi,bj            :: tile indices
C  k                :: vertical level
C  myThid           :: thread number
      INTEGER bi,bj,k
      _RS xA    (1-OLx:sNx+OLx,1-OLy:sNy+OLy)
      INTEGER myThid

C !UPDATED PARAMETERS: =================================================
C  tracer           :: tracer field
C    (NOTE: only udate the corner-halo region when using CS-grid)
      _RL tracer(1-OLx:sNx+OLx,1-OLy:sNy+OLy)

C !OUTPUT PARAMETERS: ==================================================
C  dTdx             :: zonal gradient (units = [Tr_units]*[r_units])
      _RL dTdx  (1-OLx:sNx+OLx,1-OLy:sNy+OLy)

C !LOCAL VARIABLES: ====================================================
C  i,j              :: loop indices
      INTEGER i,j
CEOP

cph-exch2#ifndef ALLOW_AUTODIFF_TAMC
C--   Internal exchange for calculations in X
      IF (useCubedSphereExchange) THEN
        CALL FILL_CS_CORNER_TR_RL( .TRUE., tracer, bi,bj, myThid )
      ENDIF
cph-exch2#endif

C     o Zonal tracer gradient
      DO j=1-Oly,sNy+Oly
       dTdx(1-Olx,j)=0.
       DO i=1-Olx+1,sNx+Olx
        dTdx(i,j) = xA(i,j)
     &            *_recip_dxC(i,j,bi,bj)*recip_deepFacC(k)
     &            *(tracer(i,j)-tracer(i-1,j))
#ifdef COSINEMETH_III
     &            *sqCosFacU(j,bi,bj)
#endif
       ENDDO
      ENDDO

      RETURN
      END
1	heimbach	1.7	C $Header: /u/gcmpack/MITgcm/pkg/generic_advdiff/gad_grad_x.F,v 1.6 2006/12/05 05:26:46 jmc Exp $
2	adcroft	1.2	C $Name: $
3	adcroft	1.1
4			#include "GAD_OPTIONS.h"
5
6	adcroft	1.2	CBOP
7			C !ROUTINE: GAD_GRAD_X
8
9			C !INTERFACE: ==========================================================
10	jmc	1.6	SUBROUTINE GAD_GRAD_X(
11	adcroft	1.1	I bi,bj,k,
12			I xA,
13	jmc	1.4	U tracer,
14	adcroft	1.1	O dTdx,
15			I myThid )
16	adcroft	1.2
17			C !DESCRIPTION:
18	adcroft	1.3	C Calculates the zonal gradient of a tracer: $\partial_x \theta
19			C = \frac{1}{\Delta x_c} \delta_i \theta$
20			C and multiplies by the area.
21	adcroft	1.2
22			C !USES: ===============================================================
23	adcroft	1.1	IMPLICIT NONE
24			#include "SIZE.h"
25	jmc	1.4	#include "EEPARAMS.h"
26	adcroft	1.1	#include "GRID.h"
27
28	adcroft	1.2	C !INPUT PARAMETERS: ===================================================
29	jmc	1.4	C bi,bj :: tile indices
30			C k :: vertical level
31			C myThid :: thread number
32	adcroft	1.1	INTEGER bi,bj,k
33			_RS xA (1-OLx:sNx+OLx,1-OLy:sNy+OLy)
34	jmc	1.4	INTEGER myThid
35
36			C !UPDATED PARAMETERS: =================================================
37			C tracer :: tracer field
38			C (NOTE: only udate the corner-halo region when using CS-grid)
39	adcroft	1.1	_RL tracer(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
40	adcroft	1.2
41			C !OUTPUT PARAMETERS: ==================================================
42	jmc	1.4	C dTdx :: zonal gradient (units = [Tr_units]*[r_units])
43	adcroft	1.1	_RL dTdx (1-OLx:sNx+OLx,1-OLy:sNy+OLy)
44
45	adcroft	1.2	C !LOCAL VARIABLES: ====================================================
46	jmc	1.4	C i,j :: loop indices
47	adcroft	1.1	INTEGER i,j
48	adcroft	1.2	CEOP
49	adcroft	1.1
50	heimbach	1.7	cph-exch2#ifndef ALLOW_AUTODIFF_TAMC
51	jmc	1.4	C-- Internal exchange for calculations in X
52			IF (useCubedSphereExchange) THEN
53			CALL FILL_CS_CORNER_TR_RL( .TRUE., tracer, bi,bj, myThid )
54			ENDIF
55	heimbach	1.7	cph-exch2#endif
56	jmc	1.4
57	adcroft	1.1	C o Zonal tracer gradient
58			DO j=1-Oly,sNy+Oly
59			dTdx(1-Olx,j)=0.
60			DO i=1-Olx+1,sNx+Olx
61	jmc	1.6	dTdx(i,j) = xA(i,j)
62			& _recip_dxC(i,j,bi,bj)recip_deepFacC(k)
63			& *(tracer(i,j)-tracer(i-1,j))
64	adcroft	1.1	#ifdef COSINEMETH_III
65	jmc	1.6	& *sqCosFacU(j,bi,bj)
66	adcroft	1.1	#endif
67			ENDDO
68			ENDDO
69
70			RETURN
71			END