x    = fspan(-5, 5, 100)
data = new( (/100,100/), float)
do y=0, 99
  data(y,:) = exp(( -(x^2)/4) - (((x(y))^2)))   ;; quick way of creating some nice data to plot. 
end do

wks = gsn_open_wks("x11","")

res                   = True
res@cnFillOn          = True
res@cnFillMode        = "RasterFill"
res@cnLinesOn         = False
res@cnLineLabelsOn    = True
res@cnLineLabelFormat = "0@;*.4f"
res@lbAutoManage      = False
res@lbOrientation     = "vertical"

;res@gsnDraw           = False
;res@gsnFrame          = False

plot = gsn_csm_contour(wks, data, res)

;---Retrieve the formatted contour label strings
getvalues plot
  "cnLineLabelStrings" : label_strings
; "cnLineLabelStrings" : res@lbLabelStrings   ; this would work too
end getvalues

res@lbLabelStrings = label_strings

;---Recreate the plot with the formatted labelbar labels
plot = gsn_csm_contour(wks, data, res)