Rg. Currie et al., DETERMINISTIC SIGNALS IN EUROPEAN FISH CATCHES, WINE HARVESTS, AND SEA-LEVEL, AND FURTHER EXPERIMENTS, International journal of climatology, 13(6), 1993, pp. 665-687
Maximum entropy spectrum analysis of six fish catch series seven serie
s giving dates of wine harvest, and forty four height of sea-level rec
ords from Europe yields evidence for two. peaks with periods 18-19 and
10-11 years, the same terms recently reported in European tree-ring c
hronologies. For each series the two wavetrains are obtained by bandpa
ss filters, summed, superimposed on the trend-like components of the r
aw data, and plotted against the raw data. The contribution, on averag
e, of the waves to total variance in the raw data varies from a high o
f 50 per cent for fish catches to a low of 14 per cent for dates of wi
ne harvest (the mean contribution for height of sea-level is 18 per ce
nt). The peaks are identified as the 18.6-year luni-solar, M(n), and 1
0-11-year solar cycle, S(c), signals, which also have been reported re
cently in other climate variables, such as air temperature, air pressu
re, in rain-gauge and tree-ring data from North and South America, Sou
th Africa, Tasmania, and New Zealand: and in sea-surface temperature a
s well as in American crop yield and other economic data. Further expe
riments show that with 110 years, or more, of data the Yule-Walker met
hod of spectrum analysis has sufficient resolution to resolve both sig
nals. It is also shown that failure to apply a properly designed digit
al high-pass filter to climate records prior to spectrum analysis usua
lly leads to failure in detecting the terms.