Autocorrelations of the Wolf Number Cycle Fragments and Solar Half-Cycle Forecast

Abstract

Autocorrelations of fragments of the Wolf number series (V2) are considered for 6-year forecasting (solar half-cycle). For physical and optimal reasons, fragments similar to one and half cycles are used. Testing is successfully performed on sufficiently reliable pairs of fragments of the series consisting of a fixed and a time-shifted fragment. A pair is selected for testing if the correlation coefficient is 0.91 or more when its components are combined. The original modification of the fixed fragment and the parts of the series following it are used. Similarly, 6-year forecasts after 2023 are produced from the fragment (2008.5–2023.5), which has correlation coefficients from 0.81 to 0.96 with fragments (1978.5–1993.5), (1901.5–1916.5), (1922.5–1937.5), (1964.5–1979.5), and (1985.5–2000.5). The maximum Wolf number (161 ± 30) is expected in mid-2024.