diff --git a/src/MNH/modeln.f90 b/src/MNH/modeln.f90
index 67536d1458b7dc61e50946a6c710461f2fa417f5..40c69a5f2fcbe0bc3f005a84094afd54a14c3996 100644
--- a/src/MNH/modeln.f90
+++ b/src/MNH/modeln.f90
@@ -1320,7 +1320,9 @@ IF (IBAK>0 .AND. IBAK <= NBAK_NUMB ) THEN
       CALL DIAG_SURF_ATM_n(YSURF_CUR%IM%DGEI, YSURF_CUR%FM%DGF, YSURF_CUR%DGL, YSURF_CUR%IM%DGI, &
                              YSURF_CUR%SM%DGS, YSURF_CUR%DGU, YSURF_CUR%TM%DGT, YSURF_CUR%WM%DGW, &
                              YSURF_CUR%U, YSURF_CUR%USS,'MESONH')
+      TFILE_SURFEX => TZBAKFILE
       CALL WRITE_DIAG_SURF_ATM_n(YSURF_CUR,'MESONH','ALL')
+      NULLIFY(TFILE_SURFEX)
     END IF
   END IF
 END IF