. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. EFFECTS OF LUNAR INCLINATION II > Q Inclination Minima ⦠« ⦠⦠« o ;6 0 ! ?/\ ' 'i ^ o '?'"a'' \ ^^ «J ^i «\ /iV ;iT '/;' ';'?\; c& W' V *i ^I. > c/f iN ^â i ^i b ib » ^i 0 6 ?; Maxima ⦠1 ⦠, ⦠1 ⦠1910 1940 1970 Year 2000 B 0 Q s o Frequency (l/yr) Figure 2. (A) Fluctuations in monthly maximum water temperature at Hopkins Marine Station (open circles). A 5-y running average of the data (solid line, not used in the calculation of periodicity) is shown to accentuate the long-term periodici
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. EFFECTS OF LUNAR INCLINATION II > Q Inclination Minima ⦠« ⦠⦠« o ;6 0 ! ?/\ ' 'i ^ o '?'"a'' \ ^^ «J ^i «\ /iV ;iT '/;' ';'?\; c& W' V *i ^I. > c/f iN ^â i ^i b ib » ^i 0 6 ?; Maxima ⦠1 ⦠, ⦠1 ⦠1910 1940 1970 Year 2000 B 0 Q s o Frequency (l/yr) Figure 2. (A) Fluctuations in monthly maximum water temperature at Hopkins Marine Station (open circles). A 5-y running average of the data (solid line, not used in the calculation of periodicity) is shown to accentuate the long-term periodicity. The strong El Nino/Southern Oscillation event of 1982-1983 is evident in the unusual duration of high temperatures in the early 1980s. (B) Power spectrum (vertical bars = SEM) of the data shown in (A). Similar results are obtained for a time series of monthly minimum temperatures (data not shown). The power spectrum of a process that fluctuates through time apportions the variance of that fluctuation among the frequencies that contribute to the process. Thus a peak in the power spectrum at a particular frequency shows that a substantial fraction of the overall variation occurred at that frequency. See (25) for a thorough explanation of spectral analysis. Monthly maximum and minimum water temperatures were extracted from the record at Hopkins Marine Station. Two gaps in the data (1940, 1965-1968) were filled by linear interpolation, and any long-term trend in the time series for each month was removed by subtracting from the data the linear regression of temperature as a function of time. The detrended data were then tapered using a Hanning window, the time series (78 points) was padded with zeroes to a length equal to the next higher power of 2 (128. a process necessary for the application of a fast Fourier transform [FFT]). and the normalized power spectral density was calculated using the FFT procedure outlined by (28). Data shown in Figure 2A are
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