c===========================================================================

      subroutine aervint(v,nz,z,vint) 1,2
c
c purpose  
c     compute aerosol density vertical integral (actually the 
c     integral increment at each level, vint=n(i)*dz  (km-1)
c     (the aerosol density can be considered dimensionless since
c     any constant factors  are normalized away in tauaero)
c
c input
c     v        visibility (km) (used to select vertical profile model)
c     z        altitude array (km)
c     nz       number of altitudes
c output
c     vint     = n(i) dz, where n(i) is the aerosol density at level i
c                averaged over the interval z(i) to z(i+1)
c                i.e., the column depth increment of aerosol density

      dimension z(*),vint(*)

      call aeroden(
      vint(1)=aden2*5.  ! (aerosol density at nz) * (5 km scale height)

      do 30 i=2,nz
        im=nz-i+1
        call aeroden(        dz=z(im+1)-z(im)
        vint(i)=dz*aden
 30   continue
      return
      end