Comparison Spectra
Belukha d180, year
=========================
ObsPer DiffPer    DerPer
-------------------------
  ()       ()      730.0
584.0      ()       ()
243.0      ()       ()
  ()       ()      208.6
172.0      ()       ()
 97.0      98.0     97.3
 74.9      74.7     74.7
(56.2)     57.0     57.0
 49.5      49.8     49.8
(42.3)    (43.7)    43.0
 37.4      37.4     37.4
(32.8)     32.6     32.1
(29.2)    (29.6)    29.5
 23.7      23.7     23.6

() not in the plots, 
(x.y) not labelled 
      in the plots

https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/trop/belukha/belukha2009.txt