anchor.diff:           wkl(4,l) = n2ovmr(iplon,l)
            wkl(6,l) = ch4vmr(iplon,l)
            wkl(7,l) = o2vmr(iplon,l)
  -         amm = (1._rb - wkl(1,l)) * amd + wkl(1,l) * amw            
  +         amm = (1._rb - wkl(1,l)) * amd + wkl(1,l) * amw
            coldry(l) = (pz(l-1)-pz(l)) * 1.e3_rb * avogad / &
                        (1.e2_rb * grav * amm * (1._rb + wkl(1,l)))
         enddo
   
   ! The following section can be used to set values for an additional layer (from
  -! the GCM top level to 1.e-4 mb) for improved calculation of TOA fluxes. 
  -! Temperature and molecular amounts in the extra model layer are set to 
  +! the GCM top level to 1.e-4 mb) for improved calculation of TOA fluxes.
  +! Temperature and molecular amounts in the extra model layer are set to
   ! their values in the top GCM model layer, though these can be modified
  -! here if necessary. 
  +! here if necessary.
   ! If this feature is utilized, increase nlayers by one above, limit the two
  -! loops above to (nlayers-1), and set the top most (nlayers) layer values here. 
  +! loops above to (nlayers-1), and set the top most (nlayers) layer values here.
   
   !      pavel(nlayers) = 0.5_rb * pz(nlayers-1)
   !      tavel(nlayers) = tavel(nlayers-1)
  
positive.code: 
  ! Transfer cloud fraction and cloud optical properties to RRTM variables;
  ! modify to reverse layer indexing here if necessary.
        if (icld .ge. 1) then 
           inflag = inflgsw
           iceflag = iceflgsw
           liqflag = liqflgsw
  
negative.code: !      coldry(nlayers) = (pz(nlayers-1)) * 1.e3_rb * avogad / &
  !                        (1.e2_rb * grav * amm * (1._rb + wkl(1,nlayers-1)))
  
  ! At this point all molecular amounts in wkl are in volume mixing ratio;
  ! convert to molec/cm2 based on coldry for use in rrtm.
  
        do l = 1, nlayers
           do imol = 1, nmol
  