Index: NEMO/branches/2019/dev_r10721_KERNEL-02_Storkey_Coward_IMMERSE_first_steps/src/OCE/C1D/step_c1d.F90
===================================================================
--- NEMO/branches/2019/dev_r10721_KERNEL-02_Storkey_Coward_IMMERSE_first_steps/src/OCE/C1D/step_c1d.F90	(revision 11482)
+++ NEMO/branches/2019/dev_r10721_KERNEL-02_Storkey_Coward_IMMERSE_first_steps/src/OCE/C1D/step_c1d.F90	(revision 11483)
@@ -6,4 +6,5 @@
    !! History :   2.0  !  2004-04  (C. Ethe)  adapted from step.F90 for C1D
    !!             3.0  !  2008-04  (G. Madec)  redo the adaptation to include SBC
+   !!             4.1  !  2019-08  (A. Coward, D. Storkey) rewrite in preparation for new timestepping scheme
    !!----------------------------------------------------------------------
 #if defined key_c1d
@@ -19,5 +20,5 @@
 #endif
    USE dyncor_c1d      ! Coriolis term (c1d case)         (dyn_cor_1d     )
-   USE dynnxt          ! time-stepping                    (dyn_nxt routine)
+   USE dynatf          ! time filtering                   (dyn_atf routine)
    USE dyndmp          ! U & V momentum damping           (dyn_dmp routine)
    USE restart         ! restart 
@@ -133,5 +134,5 @@
       Naa = Nrhs
       !
-      IF(.NOT.ln_linssh)CALL dom_vvl_sf_swp( kstp, Nbb, Nnn, Naa )                       ! swap of vertical scale factors
+      IF(.NOT.ln_linssh)CALL dom_vvl_sf_update( kstp, Nbb, Nnn, Naa )                    ! update of vertical scale factors
 
       !>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Index: NEMO/branches/2019/dev_r10721_KERNEL-02_Storkey_Coward_IMMERSE_first_steps/src/OCE/DOM/domvvl.F90
===================================================================
--- NEMO/branches/2019/dev_r10721_KERNEL-02_Storkey_Coward_IMMERSE_first_steps/src/OCE/DOM/domvvl.F90	(revision 11482)
+++ NEMO/branches/2019/dev_r10721_KERNEL-02_Storkey_Coward_IMMERSE_first_steps/src/OCE/DOM/domvvl.F90	(revision 11483)
@@ -8,4 +8,5 @@
    !!            3.3  !  2011-10  (M. Leclair) totally rewrote domvvl: vvl option includes z_star and z_tilde coordinates
    !!            3.6  !  2014-11  (P. Mathiot) add ice shelf capability
+   !!            4.1  !  2019-08  (A. Coward, D. Storkey) rename dom_vvl_sf_swp -> dom_vvl_sf_update for new timestepping
    !!----------------------------------------------------------------------
 
Index: NEMO/branches/2019/dev_r10721_KERNEL-02_Storkey_Coward_IMMERSE_first_steps/src/OFF/dtadyn.F90
===================================================================
--- NEMO/branches/2019/dev_r10721_KERNEL-02_Storkey_Coward_IMMERSE_first_steps/src/OFF/dtadyn.F90	(revision 11482)
+++ NEMO/branches/2019/dev_r10721_KERNEL-02_Storkey_Coward_IMMERSE_first_steps/src/OFF/dtadyn.F90	(revision 11483)
@@ -13,4 +13,5 @@
    !!             3.3  ! 2010-11 (C. Ethe) Full reorganization of the off-line: phasing with the on-line
    !!             3.4  ! 2011-05 (C. Ethe) Use of fldread
+   !!             4.1  ! 2019-08 (A. Coward, D. Storkey) split dta_dyn_sf_swp -> dta_dyn_sf_atf and dta_dyn_sf_interp
    !!----------------------------------------------------------------------
 
Index: NEMO/branches/2019/dev_r10721_KERNEL-02_Storkey_Coward_IMMERSE_first_steps/src/OFF/nemogcm.F90
===================================================================
--- NEMO/branches/2019/dev_r10721_KERNEL-02_Storkey_Coward_IMMERSE_first_steps/src/OFF/nemogcm.F90	(revision 11482)
+++ NEMO/branches/2019/dev_r10721_KERNEL-02_Storkey_Coward_IMMERSE_first_steps/src/OFF/nemogcm.F90	(revision 11483)
@@ -7,4 +7,5 @@
    !!            3.4  ! 2011-01  (C. Ethe, A. R. Porter, STFC Daresbury) dynamical allocation
    !!            4.0  ! 2016-10  (C. Ethe, G. Madec, S. Flavoni)  domain configuration / user defined interface
+   !!            4.1  ! 2019-08  (A. Coward, D. Storkey) rewrite in preparation for new timestepping scheme
    !!----------------------------------------------------------------------
 
Index: NEMO/branches/2019/dev_r10721_KERNEL-02_Storkey_Coward_IMMERSE_first_steps/src/TOP/TRP/trcatf.F90
===================================================================
--- NEMO/branches/2019/dev_r10721_KERNEL-02_Storkey_Coward_IMMERSE_first_steps/src/TOP/TRP/trcatf.F90	(revision 11482)
+++ NEMO/branches/2019/dev_r10721_KERNEL-02_Storkey_Coward_IMMERSE_first_steps/src/TOP/TRP/trcatf.F90	(revision 11483)
@@ -19,4 +19,5 @@
    !!            3.1  !  2009-02  (G. Madec, R. Benshila)  re-introduce the vvl option
    !!            3.3  !  2010-06  (C. Ethe, G. Madec) Merge TRA-TRC
+   !!            4.1  !  2019-08  (A. Coward, D. Storkey) rename trcnxt.F90 -> trcatf.F90. Now only does time filtering.
    !!----------------------------------------------------------------------
 #if defined key_top
@@ -58,25 +59,18 @@
       !!                   ***  ROUTINE trcatf  ***
       !!
-      !!        !!!!!!!!!!!!!!!! REWRITE HEADER COMMENTS !!!!!!!!!!!!!!
-      !!
-      !! ** Purpose :   Compute the passive tracers fields at the 
-      !!      next time-step from their temporal trends and swap the fields.
+      !! ** Purpose :   Apply the boundary condition on the after passive tracers fields and
+      !!      apply Asselin time filter to the now passive tracer fields if using leapfrog timestep
       !! 
       !! ** Method  :   Apply lateral boundary conditions on (uu(Kaa),vv(Kaa)) through 
       !!      call to lbc_lnk routine
-      !!   default:
-      !!      arrays swap
-      !!         (tr(Kmm)) = (tr(Kaa)) ; (tr(Kaa)) = (0,0)
-      !!         (tr(Kbb)) = (tr(Kmm)) 
       !!
       !!   For Arakawa or TVD Scheme : 
-      !!      A Asselin time filter applied on now tracers (tr(:,:,:,:,Kmm)) to avoid
+      !!      A Asselin time filter applied on now tracers tr(Kmm) to avoid
       !!      the divergence of two consecutive time-steps and tr arrays
       !!      to prepare the next time_step:
-      !!         (tr(Kbb)) = (tr(Kmm)) + atfp [ (tr(Kbb)) + (tr(Kaa)) - 2 (tr(Kmm)) ]
-      !!         (tr(Kmm)) = (tr(Kaa)) ; (tr(Kaa)) = (0,0)
-      !!
-      !!
-      !! ** Action  : - update tr(Kbb), tr(Kmm)
+      !!         (tr(Kmm)) = (tr(Kmm)) + atfp [ (tr(Kbb)) + (tr(Kaa)) - 2 (tr(Kmm)) ]
+      !!
+      !!
+      !! ** Action  : - update tr(Kmm), tr(Kaa)
       !!----------------------------------------------------------------------
       INTEGER                                   , INTENT( in )  :: kt             ! ocean time-step index
Index: NEMO/branches/2019/dev_r10721_KERNEL-02_Storkey_Coward_IMMERSE_first_steps/src/TOP/TRP/trcrad.F90
===================================================================
--- NEMO/branches/2019/dev_r10721_KERNEL-02_Storkey_Coward_IMMERSE_first_steps/src/TOP/TRP/trcrad.F90	(revision 11482)
+++ NEMO/branches/2019/dev_r10721_KERNEL-02_Storkey_Coward_IMMERSE_first_steps/src/TOP/TRP/trcrad.F90	(revision 11483)
@@ -6,4 +6,5 @@
    !! History :   -   !  01-01  (O. Aumont & E. Kestenare)  Original code
    !!            1.0  !  04-03  (C. Ethe)  free form F90
+   !!            4.1  !  08-19  (A. Coward, D. Storkey) tidy up using new time-level indices
    !!----------------------------------------------------------------------
 #if defined key_top
Index: NEMO/branches/2019/dev_r10721_KERNEL-02_Storkey_Coward_IMMERSE_first_steps/src/TOP/trcstp.F90
===================================================================
--- NEMO/branches/2019/dev_r10721_KERNEL-02_Storkey_Coward_IMMERSE_first_steps/src/TOP/trcstp.F90	(revision 11482)
+++ NEMO/branches/2019/dev_r10721_KERNEL-02_Storkey_Coward_IMMERSE_first_steps/src/TOP/trcstp.F90	(revision 11483)
@@ -5,4 +5,5 @@
    !!======================================================================
    !! History :  1.0  !  2004-03  (C. Ethe)  Original
+   !!            4.1  !  2019-08  (A. Coward, D. Storkey) rewrite in preparation for new timestepping scheme
    !!----------------------------------------------------------------------
 #if defined key_top
@@ -92,8 +93,4 @@
       !    
       IF( nn_dttrc == 1 )  THEN
-         IF(lwp) WRITE(numout,*) "Kbb_oce, Kmm_oce, Kaa_oce, Krhs_oce : ",Kbb_oce, Kmm_oce, Kaa_oce, Krhs_oce
-         IF(lwp) WRITE(numout,*) "Nbb_trc, Nnn_trc, Naa_trc, Nrhs_trc : ",Nbb_trc, Nnn_trc, Naa_trc, Nrhs_trc
-         IF(lwp) CALL FLUSH(numout)
-         CALL mppsync()      
          IF( Kmm_oce /= Nnn_trc .OR. Kaa_oce /= Naa_trc .OR. Krhs_oce /= Nrhs_trc ) THEN
             ! The nn_dttrc == 1 case depends on the OCE and TRC time indices being the same always. 
Index: NEMO/branches/2019/dev_r10721_KERNEL-02_Storkey_Coward_IMMERSE_first_steps/tests/VORTEX/MY_SRC/domvvl.F90
===================================================================
--- NEMO/branches/2019/dev_r10721_KERNEL-02_Storkey_Coward_IMMERSE_first_steps/tests/VORTEX/MY_SRC/domvvl.F90	(revision 11482)
+++ NEMO/branches/2019/dev_r10721_KERNEL-02_Storkey_Coward_IMMERSE_first_steps/tests/VORTEX/MY_SRC/domvvl.F90	(revision 11483)
@@ -8,4 +8,5 @@
    !!            3.3  !  2011-10  (M. Leclair) totally rewrote domvvl: vvl option includes z_star and z_tilde coordinates
    !!            3.6  !  2014-11  (P. Mathiot) add ice shelf capability
+   !!            4.1  !  2019-08  (A. Coward, D. Storkey) rename dom_vvl_sf_swp -> dom_vvl_sf_update for new timestepping
    !!----------------------------------------------------------------------
 
