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

      subroutine useralb(r,wmin,wmax,dw) 1
c
c purpose:     read user specified surface spectral reflectance
c
c discussion:  albedo data is read in from file "albedo.dat"
c
c
      parameter (mxwv=751)
      dimension r(mxwv)

      open(unit=13,file='albedo.dat',status='old',form='formatted')
      read(13,*) nn,wmin,wmax
      dw=(wmax-wmin)/(nn-1)
      read(13,*,end=20) (      close(unit=13)
      return
 20   continue
      write(*,*) 'Error in USERALB: expected ',nn,' elements'
      write(*,*) '  EOF detected at element ',i
      stop
      end