model/src/forward_step.F

C $Header: /u/u3/gcmpack/MITgcm/model/src/forward_step.F,v 1.68 2003/10/27 22:32:55 heimbach Exp $
C $Name:  $

#include "PACKAGES_CONFIG.h"
#include "CPP_OPTIONS.h"

cswdptr -- add --
#ifdef ALLOW_GCHEM
# include "GCHEM_OPTIONS.h"
#endif
cswdptr -- end add ---

CBOP
C     !ROUTINE: FORWARD_STEP
C     !INTERFACE:
      SUBROUTINE FORWARD_STEP( iloop, myTime, myIter, myThid )

C     !DESCRIPTION: \bv
C     *==================================================================
C     | SUBROUTINE forward_step
C     | o Run the ocean model and, optionally, evaluate a cost function.
C     *==================================================================
C     |
C     | THE_MAIN_LOOP is the toplevel routine for the Tangent Linear and
C     | Adjoint Model Compiler (TAMC). For this purpose the initialization
C     | of the model was split into two parts. Those parameters that do
C     | not depend on a specific model run are set in INITIALISE_FIXED,   
C     | whereas those that do depend on the specific realization are
C     | initialized in INITIALISE_VARIA.   
C     |
C     *==================================================================
C     \ev

C     !USES:
      IMPLICIT NONE
C     == Global variables ==
#include "SIZE.h"
#include "EEPARAMS.h"
#include "PARAMS.h"
#include "DYNVARS.h"
#include "FFIELDS.h"

#ifdef ALLOW_NONHYDROSTATIC
#include "CG3D.h"
#endif

#ifdef ALLOW_SHAP_FILT
#include "SHAP_FILT.h"
#endif
#ifdef ALLOW_ZONAL_FILT
#include "ZONAL_FILT.h"
#endif

#ifdef ALLOW_AUTODIFF_TAMC
# include "tamc.h"
# include "ctrl.h"
# include "ctrl_dummy.h"
# include "cost.h"
# include "EOS.h"
# ifdef ALLOW_EXF
#  include "exf_fields.h"
#  ifdef ALLOW_BULKFORMULAE
#   include "exf_constants.h"
#  endif
# endif
# ifdef ALLOW_OBCS
#  include "OBCS.h"
# endif
# ifdef ALLOW_PTRACERS
#  include "PTRACERS.h"
# endif
#endif /* ALLOW_AUTODIFF_TAMC */

C     !LOCAL VARIABLES:
C     == Routine arguments ==
C     note: under the multi-threaded model myiter and 
C           mytime are local variables passed around as routine 
C           arguments. Although this is fiddly it saves the need to 
C           impose additional synchronisation points when they are 
C           updated.
C     myiter - iteration counter for this thread
C     mytime - time counter for this thread
C     mythid - thread number for this instance of the routine.
      integer iloop
      integer mythid 
      integer myiter
      _RL     mytime
#ifdef ALLOW_BULK_FORCE
      INTEGER bi,bj
#endif

CEOP

#ifndef DISABLE_DEBUGMODE
      IF ( debugLevel .GE. debLevB ) 
     &    CALL DEBUG_ENTER('FORWARD_STEP',myThid)
#endif

#ifdef ALLOW_AUTODIFF_TAMC
C--   Reset the model iteration counter and the model time.
      myiter = nIter0 + (iloop-1)
      mytime = startTime + float(iloop-1)*deltaTclock
#endif

#if (defined (ALLOW_AUTODIFF_TAMC) && defined (ALLOW_AUTODIFF_MONITOR))
C     Include call to a dummy routine. Its adjoint will be 
C     called at the proper place in the adjoint code.
C     The adjoint routine will print out adjoint values 
C     if requested. The location of the call is important, 
C     it has to be after the adjoint of the exchanges 
C     (DO_GTERM_BLOCKING_EXCHANGES).
      CALL DUMMY_IN_STEPPING( myTime, myIter, myThid )
cph   I've commented this line since it may conflict with MITgcm's adjoint
cph   However, need to check whether that's still consistent
cph   with the ecco-branch (it should).
cph      CALL DO_FIELDS_BLOCKING_EXCHANGES( myThid )
#endif

#ifdef EXACT_CONSERV
      IF (exactConserv) THEN
C--   Update etaH(n+1) :
         CALL TIMER_START('UPDATE_ETAH        [FORWARD_STEP]',mythid)
         CALL UPDATE_ETAH( myTime, myIter, myThid )
         CALL TIMER_STOP ('UPDATE_ETAH        [FORWARD_STEP]',mythid)
      ENDIF
#endif /* EXACT_CONSERV */ 

#ifdef NONLIN_FRSURF
      IF ( select_rStar.NE.0 ) THEN
C--   r* : compute the future level thickness according to etaH(n+1) 
          CALL TIMER_START('CALC_R_STAR       [FORWARD_STEP]',mythid)
          CALL CALC_R_STAR(etaH, myTime, myIter, myThid )
          CALL TIMER_STOP ('CALC_R_STAR       [FORWARD_STEP]',mythid)
      ELSEIF ( nonlinFreeSurf.GT.0) THEN
C--   compute the future surface level thickness according to etaH(n+1) 
          CALL TIMER_START('CALC_SURF_DR      [FORWARD_STEP]',mythid)
          CALL CALC_SURF_DR(etaH, myTime, myIter, myThid )
          CALL TIMER_STOP ('CALC_SURF_DR      [FORWARD_STEP]',mythid)
      ENDIF
#endif /* NONLIN_FRSURF */

C--   Load forcing/external data fields.
#ifdef ALLOW_AUTODIFF_TAMC
c**************************************
#include "checkpoint_lev1_directives.h"
c**************************************
#endif


C--   Call external forcing package
#ifdef ALLOW_BULK_FORCE
      IF ( useBulkforce ) THEN
#ifndef DISABLE_DEBUGMODE
       IF ( debugLevel .GE. debLevB ) 
     &    CALL DEBUG_CALL('BULKF_FIELDS_LOAD',myThid)
#endif
       CALL TIMER_START('BULKF_FIELDS_LOAD[THE_MAIN_LOOP]',mythid)
       CALL BULKF_FIELDS_LOAD( mytime, myiter, mythid )
       CALL TIMER_STOP ('BULKF_FIELDS_LOAD[THE_MAIN_LOOP]',mythid)
c calculate qnet and empmr (and wind stress)
       DO bj=myByLo(myThid),myByHi(myThid)
         DO bi=myBxLo(myThid),myBxHi(myThid)
          CALL BULKF_FORCING( bi,bj, mytime, myiter, mythid )
         ENDDO
       ENDDO
c     Update the tile edges.
       _EXCH_XY_R8(Qnet,   mythid)
       _EXCH_XY_R8(EmPmR,   mythid)
       CALL EXCH_UV_XY_RS(fu, fv, .TRUE., myThid)
C       _EXCH_XY_R8(fu     , mythid)
C       _EXCH_XY_R8(fv     , mythid)
      ELSE
#endif /* ALLOW_BULK_FORCE */

# ifdef ALLOW_EXF
C     NOTE, that although the exf package is part of the
C     distribution, it is not currently maintained, i.e.
C     exf is disabled by default in genmake.
#ifndef DISABLE_DEBUGMODE
      IF ( debugLevel .GE. debLevB ) 
     &    CALL DEBUG_CALL('EXF_GETFORCING',myThid)
#endif
      CALL TIMER_START('EXF_GETFORCING     [FORWARD_STEP]',mythid)
      CALL EXF_GETFORCING( mytime, myiter, mythid )
      CALL TIMER_STOP ('EXF_GETFORCING     [FORWARD_STEP]',mythid)
# else /* ALLOW_EXF undef */
cph The following IF-statement creates an additional dependency
cph for the forcing fields requiring additional storing.
cph Therefore, the IF-statement will be put between CPP-OPTIONS,
cph assuming that ALLOW_SEAICE has not yet been differentiated.
#  ifdef ALLOW_SEAICE
      IF ( .NOT. useSEAICE ) THEN
#  endif
#ifndef DISABLE_DEBUGMODE
       IF ( debugLevel .GE. debLevB ) 
     &    CALL DEBUG_CALL('EXTERNAL_FIELDS_LOAD',myThid)
#endif
       CALL TIMER_START('EXTERNAL_FIELDS_LOAD[FORWARD_STEP]',mythid)
       CALL EXTERNAL_FIELDS_LOAD( mytime, myiter, mythid )
       CALL TIMER_STOP ('EXTERNAL_FIELDS_LOAD[FORWARD_STEP]',mythid)
#  ifdef ALLOW_SEAICE
      ENDIF
#  endif
# endif /* ALLOW_EXF */
#ifdef ALLOW_BULK_FORCE
C--   end of if/else block useBulfforce --
      ENDIF
#endif /* ALLOW_BULK_FORCE */

#ifdef ALLOW_AUTODIFF
c--   Add control vector for forcing and parameter fields
      if ( myiter .EQ. nIter0 )
     &     CALL CTRL_MAP_FORCING (mythid)
#endif

# ifdef ALLOW_SEAICE
C--   Call sea ice model to compute forcing/external data fields.  In
C     addition to computing prognostic sea-ice variables and diagnosing the
C     forcing/external data fields that drive the ocean model, SEAICE_MODEL
C     also sets theta to the freezing point under sea-ice.  The implied
C     surface heat flux is then stored in variable surfaceTendencyTice,
C     which is needed by KPP package (kpp_calc.F and kpp_transport_t.F)
C     to diagnose surface buoyancy fluxes and for the non-local transport
C     term.  Because this call precedes model thermodynamics, temperature
C     under sea-ice may not be "exactly" at the freezing point by the time
C     theta is dumped or time-averaged.
      IF ( useSEAICE ) THEN
#ifndef DISABLE_DEBUGMODE
         IF ( debugLevel .GE. debLevB ) 
     &    CALL DEBUG_CALL('SEAICE_MODEL',myThid)
#endif
         CALL TIMER_START('SEAICE_MODEL       [FORWARD_STEP]',myThid)
         CALL SEAICE_MODEL( myTime, myIter, myThid )
         CALL TIMER_STOP ('SEAICE_MODEL       [FORWARD_STEP]',myThid)
      ENDIF
# endif /* ALLOW_SEAICE */

#ifdef ALLOW_AUTODIFF_TAMC
# ifdef ALLOW_PTRACERS
cph this replaces _bibj storing of ptracer within thermodynamics
CADJ STORE ptracer  = comlev1, key = ikey_dynamics
# endif
#endif

#ifdef ALLOW_PTRACERS
# ifdef ALLOW_GCHEM
         CALL GCHEM_FIELDS_LOAD( mytime, myiter, mythid )
# endif
#endif

C--     Step forward fields and calculate time tendency terms.
#ifndef DISABLE_DEBUGMODE
      IF ( debugLevel .GE. debLevB ) 
     &    CALL DEBUG_CALL('THERMODYNAMICS',myThid)
#endif
        CALL TIMER_START('THERMODYNAMICS      [FORWARD_STEP]',mythid)
        CALL THERMODYNAMICS( myTime, myIter, myThid )
        CALL TIMER_STOP ('THERMODYNAMICS      [FORWARD_STEP]',mythid)

C--   do exchanges (needed for DYNAMICS) when using stagger time-step :
#ifndef DISABLE_DEBUGMODE
      IF ( debugLevel .GE. debLevB ) 
     &    CALL DEBUG_CALL('DO_STAGGER_FIELDS_EXCH.',myThid)
#endif
        CALL TIMER_START('BLOCKING_EXCHANGES  [FORWARD_STEP]',myThid)
        CALL DO_STAGGER_FIELDS_EXCHANGES( myTime, myIter, myThid )
        CALL TIMER_STOP ('BLOCKING_EXCHANGES  [FORWARD_STEP]',myThid)

#ifdef ALLOW_SHAP_FILT
      IF (useSHAP_FILT .AND. 
     &     staggerTimeStep .AND. shap_filt_TrStagg ) THEN
#ifndef DISABLE_DEBUGMODE
        IF ( debugLevel .GE. debLevB ) 
     &    CALL DEBUG_CALL('SHAP_FILT_APPLY_TS',myThid)
#endif
        CALL TIMER_START('SHAP_FILT           [FORWARD_STEP]',myThid)
        CALL SHAP_FILT_APPLY_TS(gT,gS,myTime+deltaT,myIter+1,myThid)
        CALL TIMER_STOP ('SHAP_FILT           [FORWARD_STEP]',myThid)
      ENDIF
#endif
#ifdef ALLOW_ZONAL_FILT
      IF (useZONAL_FILT .AND. 
     &     staggerTimeStep .AND. zonal_filt_TrStagg ) THEN
#ifndef DISABLE_DEBUGMODE
        IF ( debugLevel .GE. debLevB ) 
     &    CALL DEBUG_CALL('ZONAL_FILT_APPLY_TS',myThid)
#endif
        CALL TIMER_START('ZONAL_FILT_APPLY    [FORWARD_STEP]',myThid)
        CALL ZONAL_FILT_APPLY_TS( gT, gS, myThid )
        CALL TIMER_STOP ('ZONAL_FILT_APPLY    [FORWARD_STEP]',myThid)
      ENDIF
#endif   

C--   Step forward fields and calculate time tendency terms.
#ifndef ALLOW_AUTODIFF_TAMC
      IF ( momStepping ) THEN
#endif
#ifndef DISABLE_DEBUGMODE
        IF ( debugLevel .GE. debLevB ) 
     &    CALL DEBUG_CALL('DYNAMICS',myThid)
#endif
        CALL TIMER_START('DYNAMICS            [FORWARD_STEP]',mythid)
        CALL DYNAMICS( myTime, myIter, myThid )
        CALL TIMER_STOP ('DYNAMICS            [FORWARD_STEP]',mythid)
#ifndef ALLOW_AUTODIFF_TAMC
      ENDIF
#endif

#ifdef ALLOW_NONHYDROSTATIC
C--   Step forward W field in N-H algorithm
      IF ( momStepping .AND. nonHydrostatic ) THEN
#ifndef DISABLE_DEBUGMODE
          IF ( debugLevel .GE. debLevB ) 
     &     CALL DEBUG_CALL('CALC_GW',myThid)
#endif
         CALL TIMER_START('CALC_GW          [FORWARD_STEP]',myThid)
         CALL CALC_GW(myThid)
         CALL TIMER_STOP ('CALC_GW          [FORWARD_STEP]',myThid)
      ENDIF
#endif

#ifdef NONLIN_FRSURF
C--   update hfacC,W,S and recip_hFac according to etaH(n+1) :
      IF ( nonlinFreeSurf.GT.0) THEN
       IF ( select_rStar.GT.0 ) THEN
        CALL TIMER_START('UPDATE_R_STAR      [FORWARD_STEP]',myThid)
        CALL UPDATE_R_STAR( myTime, myIter, myThid )
        CALL TIMER_STOP ('UPDATE_R_STAR      [FORWARD_STEP]',myThid)
       ELSE
        CALL TIMER_START('UPDATE_SURF_DR     [FORWARD_STEP]',myThid)
        CALL UPDATE_SURF_DR( myTime, myIter, myThid )
        CALL TIMER_STOP ('UPDATE_SURF_DR     [FORWARD_STEP]',myThid)
       ENDIF
      ENDIF
C-    update also CG2D matrix (and preconditioner)
      IF ( momStepping .AND. nonlinFreeSurf.GT.2 ) THEN
        CALL TIMER_START('UPDATE_CG2D        [FORWARD_STEP]',myThid)
        CALL UPDATE_CG2D( myTime, myIter, myThid )
        CALL TIMER_STOP ('UPDATE_CG2D        [FORWARD_STEP]',myThid)
      ENDIF
#endif

C--   Apply Filters to u*,v* before SOLVE_FOR_PRESSURE
#ifdef ALLOW_SHAP_FILT
      IF (useSHAP_FILT .AND. shap_filt_uvStar) THEN
        CALL TIMER_START('SHAP_FILT           [FORWARD_STEP]',myThid)
        IF (implicDiv2Dflow.LT.1.) THEN
C--   Explicit+Implicit part of the Barotropic Flow Divergence
C      => Filtering of uVel,vVel is necessary
          CALL SHAP_FILT_APPLY_UV( uVel,vVel,
     &                             myTime+deltaT, myIter+1, myThid )
        ENDIF
        CALL SHAP_FILT_APPLY_UV( gU,gV,myTime+deltaT,myIter+1,myThid)
        CALL TIMER_STOP ('SHAP_FILT           [FORWARD_STEP]',myThid)
      ENDIF
#endif
#ifdef ALLOW_ZONAL_FILT
      IF (useZONAL_FILT .AND. zonal_filt_uvStar) THEN
        CALL TIMER_START('ZONAL_FILT_APPLY    [FORWARD_STEP]',myThid)
        IF (implicDiv2Dflow.LT.1.) THEN
C--   Explicit+Implicit part of the Barotropic Flow Divergence
C      => Filtering of uVel,vVel is necessary
          CALL ZONAL_FILT_APPLY_UV( uVel, vVel, myThid )
        ENDIF
        CALL ZONAL_FILT_APPLY_UV( gU, gV, myThid )
        CALL TIMER_STOP ('ZONAL_FILT_APPLY    [FORWARD_STEP]',myThid)
      ENDIF
#endif  

C--   Solve elliptic equation(s).
C     Two-dimensional only for conventional hydrostatic or 
C     three-dimensional for non-hydrostatic and/or IGW scheme.
      IF ( momStepping ) THEN
      CALL TIMER_START('SOLVE_FOR_PRESSURE  [FORWARD_STEP]',myThid)
      CALL SOLVE_FOR_PRESSURE(myTime, myIter, myThid)
      CALL TIMER_STOP ('SOLVE_FOR_PRESSURE  [FORWARD_STEP]',myThid)
      ENDIF

#ifdef ALLOW_AUTODIFF_TAMC
cph This is needed because convective_adjustment calls
cph find_rho which may use pressure()
CADJ STORE totphihyd  = comlev1, key = ikey_dynamics
#endif
C--   Correct divergence in flow field and cycle time-stepping
C     arrays (for all fields) ; update time-counter
      myIter = nIter0 + iLoop
      myTime = startTime + deltaTClock * float(iLoop)
      CALL TIMER_START('THE_CORRECTION_STEP [FORWARD_STEP]',myThid)
      CALL THE_CORRECTION_STEP(myTime, myIter, myThid)
      CALL TIMER_STOP ('THE_CORRECTION_STEP [FORWARD_STEP]',myThid)

C--   Do "blocking" sends and receives for tendency "overlap" terms
c     CALL TIMER_START('BLOCKING_EXCHANGES  [FORWARD_STEP]',myThid)
c     CALL DO_GTERM_BLOCKING_EXCHANGES( myThid )
c     CALL TIMER_STOP ('BLOCKING_EXCHANGES  [FORWARD_STEP]',myThid)

C--   Do "blocking" sends and receives for field "overlap" terms
      CALL TIMER_START('BLOCKING_EXCHANGES  [FORWARD_STEP]',myThid)
      CALL DO_FIELDS_BLOCKING_EXCHANGES( myThid )
      CALL TIMER_STOP ('BLOCKING_EXCHANGES  [FORWARD_STEP]',myThid)

cswdptr -- add for seperate timestepping of chemical/biological/forcing
cswdptr    of ptracers ---
#ifdef ALLOW_GCHEM
ceh3 This is broken -- this ifdef should not be visible!
#ifdef PTRACERS_SEPARATE_FORCING
ceh3 needs an IF ( use GCHEM ) THEN
        call GCHEM_FORCING_SEP( myTime,myIter,myThid )
#endif /* PTRACERS_SEPARATE_FORCING */
#endif /* ALLOW_GCHEM */
cswdptr -- end add ---


#ifdef ALLOW_FLT
C--   Calculate float trajectories
      IF (useFLT) THEN
        CALL TIMER_START('FLOATS            [FORWARD_STEP]',myThid)
        CALL FLT_MAIN(myIter,myTime, myThid)
        CALL TIMER_STOP ('FLOATS            [FORWARD_STEP]',myThid)
      ENDIF
#endif

#ifndef EXCLUDE_MONITOR
C--   Check status of solution (statistics, cfl, etc...)
      CALL TIMER_START('MONITOR             [FORWARD_STEP]',myThid)
      CALL MONITOR( myIter, myTime, myThid )
      CALL TIMER_STOP ('MONITOR             [FORWARD_STEP]',myThid)
#endif /* EXCLUDE_MONITOR */

C--   Do IO if needed.
      CALL TIMER_START('DO_THE_MODEL_IO     [FORWARD_STEP]',myThid)
      CALL DO_THE_MODEL_IO( myTime, myIter, myThid )
      CALL TIMER_STOP ('DO_THE_MODEL_IO     [FORWARD_STEP]',myThid)

C--   Save state for restarts
C     Note:    (jmc: is it still the case after ckp35 ?)
C     =====
C     Because of the ordering of the timestepping code and
C     tendency term code at end of loop model arrays hold
C     U,V,T,S  at "time-level" N but gu, gv, gs, gt, guNM1,... 
C     at "time-level" N+1/2 (guNM1 at "time-level" N+1/2 is 
C     gu at "time-level" N-1/2) and etaN at "time-level" N+1/2.
C      where N = I+timeLevBase-1
C     Thus a checkpoint contains U.0000000000, GU.0000000001 and 
C     etaN.0000000001 in the indexing scheme used for the model 
C     "state" files. This example is referred to as a checkpoint 
C     at time level 1 
      CALL TIMER_START('WRITE_CHECKPOINT    [FORWARD_STEP]',myThid)
      CALL WRITE_CHECKPOINT(
     &        .FALSE., myTime, myIter, myThid )
      CALL TIMER_STOP ('WRITE_CHECKPOINT    [FORWARD_STEP]',myThid)

#ifndef DISABLE_DEBUGMODE
      IF ( debugLevel .GE. debLevB ) 
     &    CALL DEBUG_LEAVE('FORWARD_STEP',myThid)
#endif

      END
1	edhill	1.69	C $Header: /u/u3/gcmpack/MITgcm/model/src/forward_step.F,v 1.68 2003/10/27 22:32:55 heimbach Exp $
2	adcroft	1.15	C $Name: $
3	adcroft	1.1
4	edhill	1.64	#include "PACKAGES_CONFIG.h"
5	adcroft	1.1	#include "CPP_OPTIONS.h"
6	edhill	1.64
7	stephd	1.55	cswdptr -- add --
8	heimbach	1.56	#ifdef ALLOW_GCHEM
9			# include "GCHEM_OPTIONS.h"
10	stephd	1.55	#endif
11			cswdptr -- end add ---
12	adcroft	1.1
13	cnh	1.22	CBOP
14			C !ROUTINE: FORWARD_STEP
15			C !INTERFACE:
16	adcroft	1.13	SUBROUTINE FORWARD_STEP( iloop, myTime, myIter, myThid )
17	heimbach	1.12
18	cnh	1.22	C !DESCRIPTION: \bv
19			C *==================================================================
20			C \| SUBROUTINE forward_step
21			C \| o Run the ocean model and, optionally, evaluate a cost function.
22			C *==================================================================
23			C \|
24			C \| THE_MAIN_LOOP is the toplevel routine for the Tangent Linear and
25			C \| Adjoint Model Compiler (TAMC). For this purpose the initialization
26			C \| of the model was split into two parts. Those parameters that do
27			C \| not depend on a specific model run are set in INITIALISE_FIXED,
28			C \| whereas those that do depend on the specific realization are
29			C \| initialized in INITIALISE_VARIA.
30			C \|
31			C *==================================================================
32			C \ev
33	adcroft	1.1
34	cnh	1.22	C !USES:
35			IMPLICIT NONE
36			C == Global variables ==
37	adcroft	1.1	#include "SIZE.h"
38			#include "EEPARAMS.h"
39			#include "PARAMS.h"
40			#include "DYNVARS.h"
41	heimbach	1.12	#include "FFIELDS.h"
42
43	adcroft	1.1	#ifdef ALLOW_NONHYDROSTATIC
44			#include "CG3D.h"
45			#endif
46
47	jmc	1.27	#ifdef ALLOW_SHAP_FILT
48			#include "SHAP_FILT.h"
49			#endif
50			#ifdef ALLOW_ZONAL_FILT
51			#include "ZONAL_FILT.h"
52			#endif
53
54	heimbach	1.12	#ifdef ALLOW_AUTODIFF_TAMC
55	heimbach	1.30	# include "tamc.h"
56			# include "ctrl.h"
57			# include "ctrl_dummy.h"
58			# include "cost.h"
59	heimbach	1.37	# include "EOS.h"
60	edhill	1.69	# ifdef ALLOW_EXF
61	heimbach	1.30	# include "exf_fields.h"
62	jmc	1.63	# ifdef ALLOW_BULKFORMULAE
63	heimbach	1.30	# include "exf_constants.h"
64			# endif
65			# endif
66			# ifdef ALLOW_OBCS
67			# include "OBCS.h"
68			# endif
69	heimbach	1.56	# ifdef ALLOW_PTRACERS
70			# include "PTRACERS.h"
71			# endif
72			#endif /* ALLOW_AUTODIFF_TAMC */
73	heimbach	1.12
74	cnh	1.22	C !LOCAL VARIABLES:
75			C == Routine arguments ==
76	adcroft	1.13	C note: under the multi-threaded model myiter and
77			C mytime are local variables passed around as routine
78			C arguments. Although this is fiddly it saves the need to
79			C impose additional synchronisation points when they are
80			C updated.
81			C myiter - iteration counter for this thread
82			C mytime - time counter for this thread
83			C mythid - thread number for this instance of the routine.
84	heimbach	1.12	integer iloop
85			integer mythid
86			integer myiter
87			_RL mytime
88	dimitri	1.45	#ifdef ALLOW_BULK_FORCE
89	jmc	1.21	INTEGER bi,bj
90	dimitri	1.50	#endif
91	heimbach	1.12
92	cnh	1.22	CEOP
93	heimbach	1.12
94	adcroft	1.53	#ifndef DISABLE_DEBUGMODE
95	heimbach	1.57	IF ( debugLevel .GE. debLevB )
96			& CALL DEBUG_ENTER('FORWARD_STEP',myThid)
97	adcroft	1.53	#endif
98
99	heimbach	1.12	#ifdef ALLOW_AUTODIFF_TAMC
100	dimitri	1.45	C-- Reset the model iteration counter and the model time.
101			myiter = nIter0 + (iloop-1)
102			mytime = startTime + float(iloop-1)*deltaTclock
103	heimbach	1.12	#endif
104
105	heimbach	1.32	#if (defined (ALLOW_AUTODIFF_TAMC) && defined (ALLOW_AUTODIFF_MONITOR))
106	dimitri	1.45	C Include call to a dummy routine. Its adjoint will be
107			C called at the proper place in the adjoint code.
108			C The adjoint routine will print out adjoint values
109			C if requested. The location of the call is important,
110			C it has to be after the adjoint of the exchanges
111			C (DO_GTERM_BLOCKING_EXCHANGES).
112			CALL DUMMY_IN_STEPPING( myTime, myIter, myThid )
113	heimbach	1.46	cph I've commented this line since it may conflict with MITgcm's adjoint
114			cph However, need to check whether that's still consistent
115			cph with the ecco-branch (it should).
116			cph CALL DO_FIELDS_BLOCKING_EXCHANGES( myThid )
117	heimbach	1.16	#endif
118
119	jmc	1.21	#ifdef EXACT_CONSERV
120			IF (exactConserv) THEN
121			C-- Update etaH(n+1) :
122	heimbach	1.36	CALL TIMER_START('UPDATE_ETAH [FORWARD_STEP]',mythid)
123	jmc	1.35	CALL UPDATE_ETAH( myTime, myIter, myThid )
124	heimbach	1.36	CALL TIMER_STOP ('UPDATE_ETAH [FORWARD_STEP]',mythid)
125	jmc	1.21	ENDIF
126			#endif /* EXACT_CONSERV */
127
128	jmc	1.18	#ifdef NONLIN_FRSURF
129	jmc	1.48	IF ( select_rStar.NE.0 ) THEN
130			C-- r* : compute the future level thickness according to etaH(n+1)
131			CALL TIMER_START('CALC_R_STAR [FORWARD_STEP]',mythid)
132			CALL CALC_R_STAR(etaH, myTime, myIter, myThid )
133			CALL TIMER_STOP ('CALC_R_STAR [FORWARD_STEP]',mythid)
134			ELSEIF ( nonlinFreeSurf.GT.0) THEN
135			C-- compute the future surface level thickness according to etaH(n+1)
136	heimbach	1.36	CALL TIMER_START('CALC_SURF_DR [FORWARD_STEP]',mythid)
137	jmc	1.21	CALL CALC_SURF_DR(etaH, myTime, myIter, myThid )
138	heimbach	1.36	CALL TIMER_STOP ('CALC_SURF_DR [FORWARD_STEP]',mythid)
139	jmc	1.48	ENDIF
140	jmc	1.21	#endif /* NONLIN_FRSURF */
141	jmc	1.18
142	dimitri	1.45	C-- Load forcing/external data fields.
143	heimbach	1.28	#ifdef ALLOW_AUTODIFF_TAMC
144			c**************************************
145			#include "checkpoint_lev1_directives.h"
146			c**************************************
147	heimbach	1.23	#endif
148	cheisey	1.38
149
150	heimbach	1.37	C-- Call external forcing package
151	cheisey	1.40	#ifdef ALLOW_BULK_FORCE
152	edhill	1.64	IF ( useBulkforce ) THEN
153	adcroft	1.53	#ifndef DISABLE_DEBUGMODE
154	jmc	1.58	IF ( debugLevel .GE. debLevB )
155	heimbach	1.57	& CALL DEBUG_CALL('BULKF_FIELDS_LOAD',myThid)
156	adcroft	1.53	#endif
157	cheisey	1.38	CALL TIMER_START('BULKF_FIELDS_LOAD[THE_MAIN_LOOP]',mythid)
158			CALL BULKF_FIELDS_LOAD( mytime, myiter, mythid )
159			CALL TIMER_STOP ('BULKF_FIELDS_LOAD[THE_MAIN_LOOP]',mythid)
160			c calculate qnet and empmr (and wind stress)
161			DO bj=myByLo(myThid),myByHi(myThid)
162			DO bi=myBxLo(myThid),myBxHi(myThid)
163			CALL BULKF_FORCING( bi,bj, mytime, myiter, mythid )
164			ENDDO
165			ENDDO
166			c Update the tile edges.
167			_EXCH_XY_R8(Qnet, mythid)
168			_EXCH_XY_R8(EmPmR, mythid)
169	cheisey	1.43	CALL EXCH_UV_XY_RS(fu, fv, .TRUE., myThid)
170			C _EXCH_XY_R8(fu , mythid)
171			C _EXCH_XY_R8(fv , mythid)
172	jmc	1.63	ELSE
173	jmc	1.58	#endif /* ALLOW_BULK_FORCE */
174	jmc	1.63
175	edhill	1.64	# ifdef ALLOW_EXF
176	dimitri	1.45	C NOTE, that although the exf package is part of the
177			C distribution, it is not currently maintained, i.e.
178			C exf is disabled by default in genmake.
179	adcroft	1.53	#ifndef DISABLE_DEBUGMODE
180	heimbach	1.57	IF ( debugLevel .GE. debLevB )
181			& CALL DEBUG_CALL('EXF_GETFORCING',myThid)
182	adcroft	1.53	#endif
183	dimitri	1.45	CALL TIMER_START('EXF_GETFORCING [FORWARD_STEP]',mythid)
184			CALL EXF_GETFORCING( mytime, myiter, mythid )
185			CALL TIMER_STOP ('EXF_GETFORCING [FORWARD_STEP]',mythid)
186	edhill	1.64	# else /* ALLOW_EXF undef */
187	heimbach	1.49	cph The following IF-statement creates an additional dependency
188			cph for the forcing fields requiring additional storing.
189			cph Therefore, the IF-statement will be put between CPP-OPTIONS,
190			cph assuming that ALLOW_SEAICE has not yet been differentiated.
191			# ifdef ALLOW_SEAICE
192	dimitri	1.45	IF ( .NOT. useSEAICE ) THEN
193	heimbach	1.49	# endif
194	adcroft	1.53	#ifndef DISABLE_DEBUGMODE
195	heimbach	1.57	IF ( debugLevel .GE. debLevB )
196			& CALL DEBUG_CALL('EXTERNAL_FIELDS_LOAD',myThid)
197	adcroft	1.53	#endif
198	dimitri	1.45	CALL TIMER_START('EXTERNAL_FIELDS_LOAD[FORWARD_STEP]',mythid)
199			CALL EXTERNAL_FIELDS_LOAD( mytime, myiter, mythid )
200			CALL TIMER_STOP ('EXTERNAL_FIELDS_LOAD[FORWARD_STEP]',mythid)
201	heimbach	1.49	# ifdef ALLOW_SEAICE
202	dimitri	1.45	ENDIF
203	heimbach	1.49	# endif
204	edhill	1.64	# endif /* ALLOW_EXF */
205	jmc	1.63	#ifdef ALLOW_BULK_FORCE
206			C-- end of if/else block useBulfforce --
207			ENDIF
208			#endif /* ALLOW_BULK_FORCE */
209	heimbach	1.49
210	heimbach	1.68	#ifdef ALLOW_AUTODIFF
211	heimbach	1.49	c-- Add control vector for forcing and parameter fields
212			if ( myiter .EQ. nIter0 )
213			& CALL CTRL_MAP_FORCING (mythid)
214			#endif
215	cheisey	1.38
216	heimbach	1.49	# ifdef ALLOW_SEAICE
217	dimitri	1.45	C-- Call sea ice model to compute forcing/external data fields. In
218			C addition to computing prognostic sea-ice variables and diagnosing the
219			C forcing/external data fields that drive the ocean model, SEAICE_MODEL
220			C also sets theta to the freezing point under sea-ice. The implied
221			C surface heat flux is then stored in variable surfaceTendencyTice,
222			C which is needed by KPP package (kpp_calc.F and kpp_transport_t.F)
223			C to diagnose surface buoyancy fluxes and for the non-local transport
224			C term. Because this call precedes model thermodynamics, temperature
225			C under sea-ice may not be "exactly" at the freezing point by the time
226			C theta is dumped or time-averaged.
227			IF ( useSEAICE ) THEN
228	adcroft	1.53	#ifndef DISABLE_DEBUGMODE
229	heimbach	1.57	IF ( debugLevel .GE. debLevB )
230			& CALL DEBUG_CALL('SEAICE_MODEL',myThid)
231	adcroft	1.53	#endif
232	heimbach	1.36	CALL TIMER_START('SEAICE_MODEL [FORWARD_STEP]',myThid)
233	jmc	1.41	CALL SEAICE_MODEL( myTime, myIter, myThid )
234	heimbach	1.36	CALL TIMER_STOP ('SEAICE_MODEL [FORWARD_STEP]',myThid)
235	dimitri	1.45	ENDIF
236	dimitri	1.50	# endif /* ALLOW_SEAICE */
237	adcroft	1.15
238	heimbach	1.56	#ifdef ALLOW_AUTODIFF_TAMC
239			# ifdef ALLOW_PTRACERS
240			cph this replaces _bibj storing of ptracer within thermodynamics
241			CADJ STORE ptracer = comlev1, key = ikey_dynamics
242			# endif
243			#endif
244	stephd	1.62
245			#ifdef ALLOW_PTRACERS
246			# ifdef ALLOW_GCHEM
247			CALL GCHEM_FIELDS_LOAD( mytime, myiter, mythid )
248			# endif
249			#endif
250
251	adcroft	1.15	C-- Step forward fields and calculate time tendency terms.
252	adcroft	1.53	#ifndef DISABLE_DEBUGMODE
253	heimbach	1.57	IF ( debugLevel .GE. debLevB )
254			& CALL DEBUG_CALL('THERMODYNAMICS',myThid)
255	adcroft	1.53	#endif
256	heimbach	1.36	CALL TIMER_START('THERMODYNAMICS [FORWARD_STEP]',mythid)
257	adcroft	1.15	CALL THERMODYNAMICS( myTime, myIter, myThid )
258	heimbach	1.36	CALL TIMER_STOP ('THERMODYNAMICS [FORWARD_STEP]',mythid)
259	jmc	1.35
260			C-- do exchanges (needed for DYNAMICS) when using stagger time-step :
261	adcroft	1.53	#ifndef DISABLE_DEBUGMODE
262	heimbach	1.57	IF ( debugLevel .GE. debLevB )
263			& CALL DEBUG_CALL('DO_STAGGER_FIELDS_EXCH.',myThid)
264	adcroft	1.53	#endif
265	heimbach	1.36	CALL TIMER_START('BLOCKING_EXCHANGES [FORWARD_STEP]',myThid)
266	jmc	1.35	CALL DO_STAGGER_FIELDS_EXCHANGES( myTime, myIter, myThid )
267	heimbach	1.36	CALL TIMER_STOP ('BLOCKING_EXCHANGES [FORWARD_STEP]',myThid)
268	jmc	1.24
269			#ifdef ALLOW_SHAP_FILT
270	dimitri	1.45	IF (useSHAP_FILT .AND.
271	jmc	1.27	& staggerTimeStep .AND. shap_filt_TrStagg ) THEN
272	adcroft	1.53	#ifndef DISABLE_DEBUGMODE
273	heimbach	1.57	IF ( debugLevel .GE. debLevB )
274			& CALL DEBUG_CALL('SHAP_FILT_APPLY_TS',myThid)
275	adcroft	1.53	#endif
276	heimbach	1.36	CALL TIMER_START('SHAP_FILT [FORWARD_STEP]',myThid)
277	jmc	1.59	CALL SHAP_FILT_APPLY_TS(gT,gS,myTime+deltaT,myIter+1,myThid)
278	heimbach	1.36	CALL TIMER_STOP ('SHAP_FILT [FORWARD_STEP]',myThid)
279	dimitri	1.45	ENDIF
280	jmc	1.24	#endif
281	jmc	1.27	#ifdef ALLOW_ZONAL_FILT
282	dimitri	1.45	IF (useZONAL_FILT .AND.
283	jmc	1.27	& staggerTimeStep .AND. zonal_filt_TrStagg ) THEN
284	adcroft	1.53	#ifndef DISABLE_DEBUGMODE
285	heimbach	1.57	IF ( debugLevel .GE. debLevB )
286			& CALL DEBUG_CALL('ZONAL_FILT_APPLY_TS',myThid)
287	adcroft	1.53	#endif
288	heimbach	1.36	CALL TIMER_START('ZONAL_FILT_APPLY [FORWARD_STEP]',myThid)
289	jmc	1.27	CALL ZONAL_FILT_APPLY_TS( gT, gS, myThid )
290	heimbach	1.36	CALL TIMER_STOP ('ZONAL_FILT_APPLY [FORWARD_STEP]',myThid)
291	jmc	1.27	ENDIF
292			#endif
293	heimbach	1.12
294	dimitri	1.45	C-- Step forward fields and calculate time tendency terms.
295	heimbach	1.61	#ifndef ALLOW_AUTODIFF_TAMC
296	dimitri	1.45	IF ( momStepping ) THEN
297	heimbach	1.61	#endif
298	adcroft	1.53	#ifndef DISABLE_DEBUGMODE
299	heimbach	1.57	IF ( debugLevel .GE. debLevB )
300			& CALL DEBUG_CALL('DYNAMICS',myThid)
301	adcroft	1.53	#endif
302	heimbach	1.36	CALL TIMER_START('DYNAMICS [FORWARD_STEP]',mythid)
303	heimbach	1.12	CALL DYNAMICS( myTime, myIter, myThid )
304	heimbach	1.36	CALL TIMER_STOP ('DYNAMICS [FORWARD_STEP]',mythid)
305	heimbach	1.61	#ifndef ALLOW_AUTODIFF_TAMC
306	dimitri	1.45	ENDIF
307	heimbach	1.61	#endif
308	heimbach	1.12
309	adcroft	1.1	#ifdef ALLOW_NONHYDROSTATIC
310			C-- Step forward W field in N-H algorithm
311	dimitri	1.45	IF ( momStepping .AND. nonHydrostatic ) THEN
312	adcroft	1.53	#ifndef DISABLE_DEBUGMODE
313	heimbach	1.57	IF ( debugLevel .GE. debLevB )
314			& CALL DEBUG_CALL('CALC_GW',myThid)
315	adcroft	1.53	#endif
316	dimitri	1.45	CALL TIMER_START('CALC_GW [FORWARD_STEP]',myThid)
317			CALL CALC_GW(myThid)
318			CALL TIMER_STOP ('CALC_GW [FORWARD_STEP]',myThid)
319			ENDIF
320	adcroft	1.1	#endif
321	jmc	1.18
322			#ifdef NONLIN_FRSURF
323	jmc	1.21	C-- update hfacC,W,S and recip_hFac according to etaH(n+1) :
324	jmc	1.18	IF ( nonlinFreeSurf.GT.0) THEN
325	jmc	1.48	IF ( select_rStar.GT.0 ) THEN
326			CALL TIMER_START('UPDATE_R_STAR [FORWARD_STEP]',myThid)
327			CALL UPDATE_R_STAR( myTime, myIter, myThid )
328			CALL TIMER_STOP ('UPDATE_R_STAR [FORWARD_STEP]',myThid)
329			ELSE
330	dimitri	1.45	CALL TIMER_START('UPDATE_SURF_DR [FORWARD_STEP]',myThid)
331	jmc	1.18	CALL UPDATE_SURF_DR( myTime, myIter, myThid )
332	heimbach	1.36	CALL TIMER_STOP ('UPDATE_SURF_DR [FORWARD_STEP]',myThid)
333	jmc	1.48	ENDIF
334	jmc	1.18	ENDIF
335			C- update also CG2D matrix (and preconditioner)
336	jmc	1.33	IF ( momStepping .AND. nonlinFreeSurf.GT.2 ) THEN
337	dimitri	1.45	CALL TIMER_START('UPDATE_CG2D [FORWARD_STEP]',myThid)
338	jmc	1.18	CALL UPDATE_CG2D( myTime, myIter, myThid )
339	jmc	1.47	CALL TIMER_STOP ('UPDATE_CG2D [FORWARD_STEP]',myThid)
340	adcroft	1.19	ENDIF
341	jmc	1.18	#endif
342	adcroft	1.1
343	jmc	1.27	C-- Apply Filters to u,v before SOLVE_FOR_PRESSURE
344			#ifdef ALLOW_SHAP_FILT
345			IF (useSHAP_FILT .AND. shap_filt_uvStar) THEN
346	heimbach	1.36	CALL TIMER_START('SHAP_FILT [FORWARD_STEP]',myThid)
347	jmc	1.27	IF (implicDiv2Dflow.LT.1.) THEN
348			C-- Explicit+Implicit part of the Barotropic Flow Divergence
349			C => Filtering of uVel,vVel is necessary
350	jmc	1.59	CALL SHAP_FILT_APPLY_UV( uVel,vVel,
351			& myTime+deltaT, myIter+1, myThid )
352	jmc	1.27	ENDIF
353	jmc	1.59	CALL SHAP_FILT_APPLY_UV( gU,gV,myTime+deltaT,myIter+1,myThid)
354	heimbach	1.36	CALL TIMER_STOP ('SHAP_FILT [FORWARD_STEP]',myThid)
355	jmc	1.27	ENDIF
356			#endif
357			#ifdef ALLOW_ZONAL_FILT
358			IF (useZONAL_FILT .AND. zonal_filt_uvStar) THEN
359	heimbach	1.36	CALL TIMER_START('ZONAL_FILT_APPLY [FORWARD_STEP]',myThid)
360	jmc	1.27	IF (implicDiv2Dflow.LT.1.) THEN
361			C-- Explicit+Implicit part of the Barotropic Flow Divergence
362			C => Filtering of uVel,vVel is necessary
363			CALL ZONAL_FILT_APPLY_UV( uVel, vVel, myThid )
364			ENDIF
365	jmc	1.59	CALL ZONAL_FILT_APPLY_UV( gU, gV, myThid )
366	heimbach	1.36	CALL TIMER_STOP ('ZONAL_FILT_APPLY [FORWARD_STEP]',myThid)
367	jmc	1.27	ENDIF
368			#endif
369	heimbach	1.12
370	adcroft	1.1	C-- Solve elliptic equation(s).
371			C Two-dimensional only for conventional hydrostatic or
372			C three-dimensional for non-hydrostatic and/or IGW scheme.
373	adcroft	1.19	IF ( momStepping ) THEN
374	heimbach	1.36	CALL TIMER_START('SOLVE_FOR_PRESSURE [FORWARD_STEP]',myThid)
375	jmc	1.31	CALL SOLVE_FOR_PRESSURE(myTime, myIter, myThid)
376	heimbach	1.36	CALL TIMER_STOP ('SOLVE_FOR_PRESSURE [FORWARD_STEP]',myThid)
377	adcroft	1.19	ENDIF
378	adcroft	1.1
379	heimbach	1.37	#ifdef ALLOW_AUTODIFF_TAMC
380			cph This is needed because convective_adjustment calls
381			cph find_rho which may use pressure()
382	heimbach	1.51	CADJ STORE totphihyd = comlev1, key = ikey_dynamics
383	heimbach	1.37	#endif
384	adcroft	1.5	C-- Correct divergence in flow field and cycle time-stepping
385	jmc	1.7	C arrays (for all fields) ; update time-counter
386	heimbach	1.12	myIter = nIter0 + iLoop
387			myTime = startTime + deltaTClock * float(iLoop)
388	heimbach	1.36	CALL TIMER_START('THE_CORRECTION_STEP [FORWARD_STEP]',myThid)
389	heimbach	1.12	CALL THE_CORRECTION_STEP(myTime, myIter, myThid)
390	heimbach	1.36	CALL TIMER_STOP ('THE_CORRECTION_STEP [FORWARD_STEP]',myThid)
391	adcroft	1.5
392	adcroft	1.1	C-- Do "blocking" sends and receives for tendency "overlap" terms
393	heimbach	1.36	c CALL TIMER_START('BLOCKING_EXCHANGES [FORWARD_STEP]',myThid)
394	jmc	1.7	c CALL DO_GTERM_BLOCKING_EXCHANGES( myThid )
395	heimbach	1.36	c CALL TIMER_STOP ('BLOCKING_EXCHANGES [FORWARD_STEP]',myThid)
396	adcroft	1.5
397			C-- Do "blocking" sends and receives for field "overlap" terms
398	heimbach	1.36	CALL TIMER_START('BLOCKING_EXCHANGES [FORWARD_STEP]',myThid)
399	adcroft	1.5	CALL DO_FIELDS_BLOCKING_EXCHANGES( myThid )
400	heimbach	1.36	CALL TIMER_STOP ('BLOCKING_EXCHANGES [FORWARD_STEP]',myThid)
401	stephd	1.54
402			cswdptr -- add for seperate timestepping of chemical/biological/forcing
403			cswdptr of ptracers ---
404	heimbach	1.56	#ifdef ALLOW_GCHEM
405	edhill	1.64	ceh3 This is broken -- this ifdef should not be visible!
406	stephd	1.62	#ifdef PTRACERS_SEPARATE_FORCING
407	edhill	1.64	ceh3 needs an IF ( use GCHEM ) THEN
408	stephd	1.62	call GCHEM_FORCING_SEP( myTime,myIter,myThid )
409	edhill	1.64	#endif /* PTRACERS_SEPARATE_FORCING */
410			#endif /* ALLOW_GCHEM */
411	stephd	1.54	cswdptr -- end add ---
412
413	adcroft	1.20
414			#ifdef ALLOW_FLT
415			C-- Calculate float trajectories
416			IF (useFLT) THEN
417	heimbach	1.36	CALL TIMER_START('FLOATS [FORWARD_STEP]',myThid)
418	adcroft	1.20	CALL FLT_MAIN(myIter,myTime, myThid)
419	heimbach	1.36	CALL TIMER_STOP ('FLOATS [FORWARD_STEP]',myThid)
420	adcroft	1.20	ENDIF
421			#endif
422	heimbach	1.12
423			#ifndef EXCLUDE_MONITOR
424			C-- Check status of solution (statistics, cfl, etc...)
425	dimitri	1.45	CALL TIMER_START('MONITOR [FORWARD_STEP]',myThid)
426	heimbach	1.12	CALL MONITOR( myIter, myTime, myThid )
427	heimbach	1.36	CALL TIMER_STOP ('MONITOR [FORWARD_STEP]',myThid)
428	heimbach	1.12	#endif /* EXCLUDE_MONITOR */
429	adcroft	1.1
430	jmc	1.7	C-- Do IO if needed.
431	heimbach	1.36	CALL TIMER_START('DO_THE_MODEL_IO [FORWARD_STEP]',myThid)
432	heimbach	1.12	CALL DO_THE_MODEL_IO( myTime, myIter, myThid )
433	heimbach	1.36	CALL TIMER_STOP ('DO_THE_MODEL_IO [FORWARD_STEP]',myThid)
434	adcroft	1.1
435			C-- Save state for restarts
436	jmc	1.7	C Note: (jmc: is it still the case after ckp35 ?)
437	adcroft	1.1	C =====
438			C Because of the ordering of the timestepping code and
439			C tendency term code at end of loop model arrays hold
440			C U,V,T,S at "time-level" N but gu, gv, gs, gt, guNM1,...
441			C at "time-level" N+1/2 (guNM1 at "time-level" N+1/2 is
442	jmc	1.10	C gu at "time-level" N-1/2) and etaN at "time-level" N+1/2.
443	adcroft	1.1	C where N = I+timeLevBase-1
444			C Thus a checkpoint contains U.0000000000, GU.0000000001 and
445	jmc	1.10	C etaN.0000000001 in the indexing scheme used for the model
446	adcroft	1.1	C "state" files. This example is referred to as a checkpoint
447			C at time level 1
448	heimbach	1.36	CALL TIMER_START('WRITE_CHECKPOINT [FORWARD_STEP]',myThid)
449	adcroft	1.1	CALL WRITE_CHECKPOINT(
450	heimbach	1.12	& .FALSE., myTime, myIter, myThid )
451	heimbach	1.36	CALL TIMER_STOP ('WRITE_CHECKPOINT [FORWARD_STEP]',myThid)
452	adcroft	1.53
453			#ifndef DISABLE_DEBUGMODE
454	heimbach	1.57	IF ( debugLevel .GE. debLevB )
455			& CALL DEBUG_LEAVE('FORWARD_STEP',myThid)
456	adcroft	1.53	#endif
457	adcroft	1.1
458			END