pkg/mom_fluxform/mom_v_bottomdrag.F

C $Header: /u/gcmpack/MITgcm/pkg/mom_fluxform/mom_v_bottomdrag.F,v 1.5 2002/11/29 13:38:38 heimbach Exp $
C $Name:  $

#include "CPP_OPTIONS.h"

CBOP
C !ROUTINE: MOM_V_BOTTOMDRAG

C !INTERFACE: ==========================================================
      SUBROUTINE MOM_V_BOTTOMDRAG(
     I        bi,bj,k,
     I        vFld, KE, KappaRV,
     O        vDragTerms,
     I        myThid)

C !DESCRIPTION:
C Calculates the drag due to friction and the no-slip condition at bottom:
C \begin{equation*}
C G^v_{drag} = - ( r_b + C_D |v| + \frac{2}{\Delta r_c} ) v
C \end{equation*}

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

C !INPUT PARAMETERS: ===================================================
C  bi,bj                :: tile indices
C  k                    :: vertical level
C  vFld                 :: meridional flow
C  KE                   :: Kinetic energy
C  KappaRV              :: vertical viscosity
C  myThid               :: thread number
      INTEGER bi,bj,k
      _RL vFld(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
      _RL KE(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
      _RL KappaRV(1-OLx:sNx+OLx,1-OLy:sNy+OLy,Nr)
      _RL viscFac
      INTEGER myThid

C !OUTPUT PARAMETERS: ==================================================
C  vDragTerms           :: drag term
      _RL vDragTerms(1-OLx:sNx+OLx,1-OLy:sNy+OLy)

C !LOCAL VARIABLES: ====================================================
C  i,j                  :: loop indices
C  Kp1                  :: =k+1 for k<Nr, =Nr for k>=Nr
      INTEGER I,J,kDown,kDownC,kBottom
      _RL rdrckp1,maskDown
CEOP

C-  No-slip BCs impose a drag at bottom
      IF ( buoyancyRelation .EQ. 'OCEANIC' ) THEN
       kBottom = Nr
       kDown   = min(k+1,kBottom)
       kDownC  = kDown
      ELSEIF ( buoyancyRelation .EQ. 'OCEANICP' .OR.
     &         buoyancyRelation .EQ. 'ATMOSPHERIC' ) THEN
       kBottom = 1
       kDown   = max(k-1,kBottom)
       kDownC  = k
      ELSE      
       STOP 'S/R MOM_U_BOTTOMDRAG: We should never reach this point!'
      ENDIF     
      rdrckp1=recip_drC(kDownC)
      viscFac=1.
      IF (.NOT. no_slip_bottom) viscFac=0.
      IF (k.EQ.kBottom) rdrckp1=recip_drF(k)
      DO j=1-Oly+1,sNy+Oly-1
       DO i=1-Olx,sNx+Olx-1
        maskDown=_maskS(i,j,kdown,bi,bj)
        IF (k.EQ.kBottom) maskDown=0.
        vDragTerms(i,j)=
     &   -_recip_hFacS(i,j,k,bi,bj)*recip_drF(k)
     &   *( 
     &      2.*KappaRV(i,j,kDownC)*rkFac*rdrckp1*viscFac
#if (defined (ALLOW_AUTODIFF_TAMC) && \
    defined (ALLOW_BOTTOMDRAG_CONTROL))
     &     + bottomdragfld(i,j,bi,bj)
#else
     &     + bottomDragLinear
#endif
     &    )*(1.-maskDown)*vFld(i,j)
        IF ( (KE(i,j)+KE(i,j-1)) .NE. 0. ) THEN
         vDragTerms(i,j)=vDragTerms(i,j)
     &    -_recip_hFacS(i,j,k,bi,bj)*recip_drF(k)
     &    *bottomDragQuadratic*sqrt(KE(i,j)+KE(i,j-1))
     &    *(1.-maskDown)*vFld(i,j)
        ENDIF
       ENDDO
      ENDDO

      RETURN
      END
1	C $Header: /u/gcmpack/MITgcm/pkg/mom_fluxform/mom_v_bottomdrag.F,v 1.5 2002/11/29 13:38:38 heimbach Exp $
2	C $Name: $
3
4	#include "CPP_OPTIONS.h"
5
6	CBOP
7	C !ROUTINE: MOM_V_BOTTOMDRAG
8
9	C !INTERFACE: ==========================================================
10	SUBROUTINE MOM_V_BOTTOMDRAG(
11	I bi,bj,k,
12	I vFld, KE, KappaRV,
13	O vDragTerms,
14	I myThid)
15
16	C !DESCRIPTION:
17	C Calculates the drag due to friction and the no-slip condition at bottom:
18	C \begin{equation*}
19	C G^v_{drag} = - ( r_b + C_D \|v\| + \frac{2}{\Delta r_c} ) v
20	C \end{equation*}
21
22	C !USES: ===============================================================
23	IMPLICIT NONE
24	#include "SIZE.h"
25	#include "EEPARAMS.h"
26	#include "PARAMS.h"
27	#include "GRID.h"
28
29	C !INPUT PARAMETERS: ===================================================
30	C bi,bj :: tile indices
31	C k :: vertical level
32	C vFld :: meridional flow
33	C KE :: Kinetic energy
34	C KappaRV :: vertical viscosity
35	C myThid :: thread number
36	INTEGER bi,bj,k
37	_RL vFld(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
38	_RL KE(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
39	_RL KappaRV(1-OLx:sNx+OLx,1-OLy:sNy+OLy,Nr)
40	_RL viscFac
41	INTEGER myThid
42
43	C !OUTPUT PARAMETERS: ==================================================
44	C vDragTerms :: drag term
45	_RL vDragTerms(1-OLx:sNx+OLx,1-OLy:sNy+OLy)
46
47	C !LOCAL VARIABLES: ====================================================
48	C i,j :: loop indices
49	C Kp1 :: =k+1 for k<Nr, =Nr for k>=Nr
50	INTEGER I,J,kDown,kDownC,kBottom
51	_RL rdrckp1,maskDown
52	CEOP
53
54	C- No-slip BCs impose a drag at bottom
55	IF ( buoyancyRelation .EQ. 'OCEANIC' ) THEN
56	kBottom = Nr
57	kDown = min(k+1,kBottom)
58	kDownC = kDown
59	ELSEIF ( buoyancyRelation .EQ. 'OCEANICP' .OR.
60	& buoyancyRelation .EQ. 'ATMOSPHERIC' ) THEN
61	kBottom = 1
62	kDown = max(k-1,kBottom)
63	kDownC = k
64	ELSE
65	STOP 'S/R MOM_U_BOTTOMDRAG: We should never reach this point!'
66	ENDIF
67	rdrckp1=recip_drC(kDownC)
68	viscFac=1.
69	IF (.NOT. no_slip_bottom) viscFac=0.
70	IF (k.EQ.kBottom) rdrckp1=recip_drF(k)
71	DO j=1-Oly+1,sNy+Oly-1
72	DO i=1-Olx,sNx+Olx-1
73	maskDown=_maskS(i,j,kdown,bi,bj)
74	IF (k.EQ.kBottom) maskDown=0.
75	vDragTerms(i,j)=
76	& -_recip_hFacS(i,j,k,bi,bj)*recip_drF(k)
77	& *(
78	& 2.KappaRV(i,j,kDownC)rkFacrdrckp1viscFac
79	#if (defined (ALLOW_AUTODIFF_TAMC) && \
80	defined (ALLOW_BOTTOMDRAG_CONTROL))
81	& + bottomdragfld(i,j,bi,bj)
82	#else
83	& + bottomDragLinear
84	#endif
85	& )(1.-maskDown)vFld(i,j)
86	IF ( (KE(i,j)+KE(i,j-1)) .NE. 0. ) THEN
87	vDragTerms(i,j)=vDragTerms(i,j)
88	& -_recip_hFacS(i,j,k,bi,bj)*recip_drF(k)
89	& bottomDragQuadraticsqrt(KE(i,j)+KE(i,j-1))
90	& (1.-maskDown)vFld(i,j)
91	ENDIF
92	ENDDO
93	ENDDO
94
95	RETURN
96	END