diff --git a/src/MNH/mnhopen_aux_io_surf.f90 b/src/MNH/mnhopen_aux_io_surf.f90
index 1ecf5dcccce236a4d08eafd1882a2009bf519750..0feac5888ef9fa8ae713e732e17cc927d90b5cd6 100644
--- a/src/MNH/mnhopen_aux_io_surf.f90
+++ b/src/MNH/mnhopen_aux_io_surf.f90
@@ -134,6 +134,7 @@ COUTFILE = HFILE
 CALL FMREAD(HFILE,'IMAX',COUT,'--',IIMAX,IGRID,ILENCH,YCOMMENT,IRESP)
 CALL FMREAD(HFILE,'JMAX',COUT,'--',IJMAX,IGRID,ILENCH,YCOMMENT,IRESP)
 CALL MNH_SURF_GRID_IO_INIT(IIMAX,IJMAX)
+IJPHEXT= 1
 CALL FMREAD(HFILE,'JPHEXT',COUT,'--',IJPHEXT,IGRID,ILENCH,YCOMMENT,IRESP)
 IF ( IJPHEXT .NE. JPHEXT ) THEN
    WRITE(NLUOUT,FMT=*) ' MNHOPEN_AUX_IO : JPHEXT in PRE_PGD1.nam/NAM_CONF_PGD ( or default value )&