diff --git a/src/MNH/modd_sub_modeln.f90 b/src/MNH/modd_sub_modeln.f90
index 5f08f0b0258c454e3cd8859f056519ef024d4945..c09ff09130140f34d41981449b83f2ef46283a83 100644
--- a/src/MNH/modd_sub_modeln.f90
+++ b/src/MNH/modd_sub_modeln.f90
@@ -1,4 +1,4 @@
-!MNH_LIC Copyright 1994-2019 CNRS, Meteo-France and Universite Paul Sabatier
+!MNH_LIC Copyright 1994-2021 CNRS, Meteo-France and Universite Paul Sabatier
 !MNH_LIC This is part of the Meso-NH software governed by the CeCILL-C licence
 !MNH_LIC version 1. See LICENSE, CeCILL-C_V1-en.txt and CeCILL-C_V1-fr.txt
 !MNH_LIC for details. version 1.
@@ -10,6 +10,7 @@
 !  P. Wautelet 28/03/2019: use MNHTIME for time measurement variables
 !  J. Escobar  09/07/2019: norme Doctor -> Rename Module Type variable TZ -> T
 !  J. Escobar  09/07/2019: for bug in management of XLSZWSM variable, add/use specific 2D TLSFIELD2D_ll pointer
+!  P. Wautelet 07/01/2021: rename ibak/iout into nfile_backup_current/nfile_output_current
 !-----------------------------------------------------------------
 !     #################
       MODULE MODD_SUB_MODEL_n
@@ -36,7 +37,8 @@ TYPE SUB_MODEL_t
   TYPE(HALO2LIST_ll), POINTER :: THALO2T_ll  => NULL()
   TYPE(HALO2LIST_ll), POINTER :: THALO2MT_ll => NULL()
   TYPE(HALO2LIST_ll), POINTER :: THALO2SC_ll => NULL()
-  INTEGER :: IBAK, IOUT          ! number of the backup / output
+  integer :: nfile_backup_current = 0 ! Number of the current backup file
+  integer :: nfile_output_current = 0 ! Number of the current output file
   REAL(kind=MNHTIME), DIMENSION(2) :: XT_START
   REAL(kind=MNHTIME), DIMENSION(2) :: XT_STORE, XT_BOUND, XT_GUESS
   REAL(kind=MNHTIME), DIMENSION(2) :: XT_ADV, XT_SOURCES, XT_DRAG
@@ -64,8 +66,8 @@ TYPE(LIST_ll), POINTER :: TLSFIELD2D_ll => NULL()
 TYPE(LIST_ll), POINTER :: TFIELDT_ll=>NULL(),TFIELDMT_ll=>NULL(),TFIELDSC_ll=>NULL()
 TYPE(HALO2LIST_ll), POINTER :: THALO2M_ll=>NULL(), TLSHALO2_ll=>NULL()
 TYPE(HALO2LIST_ll), POINTER :: THALO2T_ll=>NULL(), THALO2MT_ll=>NULL(), THALO2SC_ll=>NULL()
-INTEGER, POINTER :: IBAK=>NULL()
-INTEGER, POINTER :: IOUT=>NULL()
+integer, pointer :: nfile_backup_current => Null()
+integer, pointer :: nfile_output_current => Null()
 REAL(kind=MNHTIME), DIMENSION(:), POINTER :: XT_START=>NULL()
 REAL(kind=MNHTIME), DIMENSION(:), POINTER :: XT_STORE=>NULL(), XT_BOUND=>NULL(), XT_GUESS=>NULL()
 REAL(kind=MNHTIME), DIMENSION(:), POINTER :: XT_ADV=>NULL(), XT_SOURCES=>NULL(), XT_DRAG=>NULL()
@@ -117,8 +119,8 @@ TLSHALO2_ll=>SUB_MODEL_MODEL(KTO)%TLSHALO2_ll
 THALO2T_ll=>SUB_MODEL_MODEL(KTO)%THALO2T_ll
 THALO2MT_ll=>SUB_MODEL_MODEL(KTO)%THALO2MT_ll
 THALO2SC_ll=>SUB_MODEL_MODEL(KTO)%THALO2SC_ll
-IBAK=>SUB_MODEL_MODEL(KTO)%IBAK
-IOUT=>SUB_MODEL_MODEL(KTO)%IOUT
+nfile_backup_current => sub_model_model(kto)%nfile_backup_current
+nfile_output_current => sub_model_model(kto)%nfile_output_current
 XT_START=>SUB_MODEL_MODEL(KTO)%XT_START
 XT_STORE=>SUB_MODEL_MODEL(KTO)%XT_STORE
 XT_BOUND=>SUB_MODEL_MODEL(KTO)%XT_BOUND
diff --git a/src/MNH/modeln.f90 b/src/MNH/modeln.f90
index b7958c13fe04ae30d3172ad45823e96ba616a3c2..892a3b913ec7046c4c867c03a5a9af334e354318 100644
--- a/src/MNH/modeln.f90
+++ b/src/MNH/modeln.f90
@@ -610,10 +610,6 @@ IF (KTCOUNT == 1) THEN
 !
   ALLOCATE(XWT_ACT_NUC(SIZE(XWT,1),SIZE(XWT,2),SIZE(XWT,3)))
   ALLOCATE(GMASKkids(SIZE(XWT,1),SIZE(XWT,2)))
-!
-! initialization of the FM file backup/output number
-  IBAK=0
-  IOUT=0
 !
   IF ( .NOT. LIO_NO_WRITE ) THEN
     CALL IO_File_open(TDIAFILE)
@@ -915,19 +911,19 @@ IF (CSURF=='EXTE') CALL GOTO_SURFEX(IMI)
 !
 ZTIME1 = ZTIME2
 !
-IF (IBAK < NBAK_NUMB ) THEN
-  IF (KTCOUNT == TBACKUPN(IBAK+1)%NSTEP) THEN
-    IBAK=IBAK+1
+IF ( nfile_backup_current < NBAK_NUMB ) THEN
+  IF ( KTCOUNT == TBACKUPN(nfile_backup_current + 1)%NSTEP ) THEN
+    nfile_backup_current = nfile_backup_current + 1
     GCLOSE_OUT=.TRUE.
     !
-    TZBAKFILE => TBACKUPN(IBAK)%TFILE
+    TZBAKFILE => TBACKUPN(nfile_backup_current)%TFILE
     IVERB    = TZBAKFILE%NLFIVERB
     !
     CALL IO_File_open(TZBAKFILE)
     !
     CALL WRITE_DESFM_n(IMI,TZBAKFILE)
-    CALL IO_Header_write(TBACKUPN(IBAK)%TFILE)
-    CALL WRITE_LFIFM_n(TBACKUPN(IBAK)%TFILE,TBACKUPN(IBAK)%TFILE%TDADFILE%CNAME)
+    CALL IO_Header_write( TBACKUPN(nfile_backup_current)%TFILE )
+    CALL WRITE_LFIFM_n( TBACKUPN(nfile_backup_current)%TFILE, TBACKUPN(nfile_backup_current)%TFILE%TDADFILE%CNAME )
     TOUTDATAFILE => TZBAKFILE
     CALL MNHWRITE_ZS_DUMMY_n(TZBAKFILE)
     IF (CSURF=='EXTE') THEN
@@ -960,17 +956,17 @@ ELSE
   TZBAKFILE => TFILE_DUMMY
 END IF
 !
-IF (IOUT < NOUT_NUMB ) THEN
-  IF (KTCOUNT == TOUTPUTN(IOUT+1)%NSTEP) THEN
-    IOUT=IOUT+1
+IF ( nfile_output_current < NOUT_NUMB ) THEN
+  IF ( KTCOUNT == TOUTPUTN(nfile_output_current + 1)%NSTEP ) THEN
+    nfile_output_current = nfile_output_current + 1
     !
-    TZOUTFILE => TOUTPUTN(IOUT)%TFILE
+    TZOUTFILE => TOUTPUTN(nfile_output_current)%TFILE
     !
     CALL IO_File_open(TZOUTFILE)
     !
     CALL IO_Header_write(TZOUTFILE)
-    CALL IO_Fieldlist_write(TOUTPUTN(IOUT))
-    CALL IO_Field_user_write(TOUTPUTN(IOUT))
+    CALL IO_Fieldlist_write(  TOUTPUTN(nfile_output_current) )
+    CALL IO_Field_user_write( TOUTPUTN(nfile_output_current) )
     !
     CALL IO_File_close(TZOUTFILE)
     !
@@ -1340,8 +1336,8 @@ IF (CDCONV/='NONE') THEN
   END IF
 END IF
 !
-IF (IBAK>0 .AND. IBAK <= NBAK_NUMB ) THEN
-  IF (KTCOUNT == TBACKUPN(IBAK)%NSTEP) THEN
+IF ( nfile_backup_current > 0 .AND. nfile_backup_current <= NBAK_NUMB ) THEN
+  IF ( KTCOUNT == TBACKUPN(nfile_backup_current)%NSTEP ) THEN
     IF (CSURF=='EXTE') THEN
       CALL GOTO_SURFEX(IMI)
       CALL DIAG_SURF_ATM_n(YSURF_CUR,'MESONH')