Autocorrelation of Solar Activity

Abstract

IN this communication we examine the autocorrelation function R of various indexes of solar activity over time-lags,τ, of 1–200 days. Four indexes of solar activity were used: the daily relative sunspot number (Zurich), and the mean daily fluxes from Nagoya at the frequencies 1,000 Mc/s, 3,750 Mc/s and 9,400 Mc/s. The data were analysed for the years 1957–58 (more than 700 days) and for the years 1960–63 (900 days), thus comparing the highly active years of the solar cycle with the less-active years. In addition, the relative sunspot numbers for the years 1947–48 and 1937–38 were analysed for comparison.