Index: trunk/LMDZ.TITAN/libf/phytitan/optci.F90
===================================================================
--- trunk/LMDZ.TITAN/libf/phytitan/optci.F90	(revision 3659)
+++ trunk/LMDZ.TITAN/libf/phytitan/optci.F90	(revision 3660)
@@ -173,4 +173,11 @@
    end do ! L_LEVELS
 
+   ! initialize k=1 level (to avoid NaN values and error in debug mode)
+   DIAG_OPTT(1,:,1) = 0.0 ! dtau
+   DIAG_OPTT(1,:,2) = 1.0  ! wbar
+   DIAG_OPTT(1,:,3) = 1.0  ! gbar
+   DIAG_OPTT(1,:,4) = 0.d0
+   DIAG_OPTT(1,:,5) = 0.d0
+
    do NW=1,L_NSPECTI
       ! We ignore K=1...
@@ -336,5 +343,5 @@
                DIAG_OPTT(k,nw,3) = 1.0  ! gbar
             ENDIF
-            
+
          ! Optics and microphysics no coupled :
          ELSE