Index: LMDZ6/trunk/libf/phylmd/StratAer/strataer_local_var_mod.f90
===================================================================
--- LMDZ6/trunk/libf/phylmd/StratAer/strataer_local_var_mod.f90	(revision 5651)
+++ LMDZ6/trunk/libf/phylmd/StratAer/strataer_local_var_mod.f90	(revision 5652)
@@ -259,16 +259,21 @@
     
     !--initialising dry diameters to geometrically spaced mass/volume (see Jacobson 1994)
-    mdw(1)=mdwmin
-    IF (V_rat.LT.1.62) THEN ! compensate for dip in second bin for lower volume ratio
-       mdw(2)=mdw(1)*2.**(1./3.)
-       DO it=3, nbtr_bin
-          mdw(it)=mdw(it-1)*V_rat**(1./3.)
-       ENDDO
+    IF(nbtr_bin < 3) THEN
+       WRITE(lunout,*) 'WARNING: There are less than 3 sulfur aerosol class, it could be a problem for StratAer usage !'
+       WRITE(lunout,*) 'NBTR_BIN=',nbtr_bin
     ELSE
-       DO it=2, nbtr_bin
-          mdw(it)=mdw(it-1)*V_rat**(1./3.)
-       ENDDO
-    ENDIF
-    IF (is_master) WRITE(lunout,*) 'init mdw=', mdw
+       mdw(1)=mdwmin
+       IF (V_rat.LT.1.62) THEN ! compensate for dip in second bin for lower volume ratio
+          mdw(2)=mdw(1)*2.**(1./3.)
+          DO it=3, nbtr_bin
+             mdw(it)=mdw(it-1)*V_rat**(1./3.)
+          ENDDO
+       ELSE
+          DO it=2, nbtr_bin
+             mdw(it)=mdw(it-1)*V_rat**(1./3.)
+          ENDDO
+       ENDIF
+       IF (is_master) WRITE(lunout,*) 'init mdw=', mdw
+    ENDIF
     
     !   compute particle radius RRSI [cm] and volume Vbin [m3] from diameter mdw [m]