; To fix the bug, download the gsn_csm_640_fix.ncl file and uncomment this line.

  f     = addfile ("$NCARG_ROOT/lib/ncarg/data/cdf/uv300.nc","r")
  u     = f->U 

  wks   = gsn_open_wks ("png","xyreflinebug")

  res                       = True
  res@gsnMaximize           = True

  res@xyMarkLineMode        = "MarkLines"
  res@xyLineThicknessF      = 3.0
  res@xyMarkerThicknessF    = 2.0
  res@xyMarkerSizeF         = 0.01
  res@xyMarkers             = 16
  res@xyMarkerColor         = "seagreen"


  res@gsnYRefLine           = 21
  res@gsnYRefLineColor      = "saddlebrown"
  res@gsnYRefLineThicknessF = 5.0

  res@tiMainFontHeightF     = 0.018
  res@tiMainString          = "NCL Version " + get_ncl_version()

  plot1 = gsn_csm_xy (wks,u&lat,u(0,:,{82}),res)