anchor.diff:            ch4vmr=ch4vmr*1.e-09
          ENDIF
       ENDIF
  -    
  +
       IF (PRESENT(cfc11vmr)) THEN
          cfc11vmr = -9999.999
          if (found_yearIN /= 0) then
  
positive.code:              CALL interpolate_CAMgases(yr, julian, nyrm, njulm, yr1, yr2, nyrp, njulp, n2or, n2ovmr)
            ENDIF
         endif
         
         IF (n2ovmr < 0. .or. found_yearIN == 0) THEN
            CALL orig_val("N2O",model,n2ovmr)
         ELSE
            ! If extrapolation, need to bound the data to pre-industrial concentrations
            if (n2ovmr < 270.) n2ovmr = 270.          
            n2ovmr=n2ovmr*1.e-09
         ENDIF
         
      ENDIF
      
      IF (PRESENT(ch4vmr)) THEN
         ch4vmr=-9999.999
         if (found_yearIN /= 0) then
  
negative.code:     REAL                                      :: doymodel, doydatam, doydatap,    &
                                                   deltat, fact1, fact2, x
      INTEGER                                   :: ny, my1,my2,my3,nday, maxyear, minyear
  
  
      ! Add support for leap-years
  
      ! Find smallest and largest year: yearf >= yeari since the file is ordered with increasing dates.
  