Subroutine Write_ENSO (Fname)
Integer :: ilon, ilat, it, ist 
Integer, Parameter :: NEnso=4
!Real, Dimension (N_ClimIDX, Ntime) :: ClimIDX

Real :: ENSO(Ntime,NEnso), Xlon(Ntime), Xlat(NEnso) 
Character (Len=*) :: Fname

! write ONI as Enso definition: ONI<=0.5: La Nina; >=0.5: El Nino; in between this interval is Neutral

ENSO(:,:)=0.0
Do ilon=1, Ntime; Xlon(ilon)=ilon; Enddo        ! Mang Lon
Xlat(1)=-1; Xlat(2)=0; Xlat(3)=1; Xlat(4)=3     ! All=3; El Nino=1; La Nina=-1; Neutral=0
Do it=1, Ntime
   ENSO(it,4)=ClimIDX(1,it)           ! All
   if (ClimIDX(1,it)<=-0.5) then      ! La Nina
      ENSO(it,1)=ClimIDX(1,it)
   else if (ClimIDX(1,it)>=0.5) then  ! El Nino
      ENSO(it,3)=ClimIDX(1,it)
   else
      ENSO(it,2)=ClimIDX(1,it)        ! Neutral
   endif
Enddo

Call wr_ncdf_2d (trim(Fname), Xlon, Xlat, Ntime, NEnso, ENSO, "ONI", "ONI used as ENSO classification", "C", "Mon","Enso",Miss)

End Subroutine Write_ENSO