On the Prediction of Solar Cycles

Abstract

This article deals with the prediction of the upcoming solar activity cycle, Solar Cycle 25. We propose that astronomical ephemeris, specifically taken from the catalogs of aphelia of the four Jovian planets, could be drivers of variations in solar activity, represented by the series of sunspot numbers (SSN) from 1749 to 2020. We use singular spectrum analysis (SSA) to associate components with similar periods in the ephemeris and SSN. We determine the transfer function between the two data sets. We improve the match in successive steps: first with Jupiter only, then with the four Jovian planets and finally including commensurable periods of pairs and pairs of pairs of the Jovian planets (following Mörth and Schlamminger in Planetary Motion, Sunspots and Climate, Solar-Terrestrial Influences on Weather and Climate, 193, 1979). The transfer function can be applied to the ephemeris to predict future cycles. We test this with success using the “hindcast prediction” of Solar Cycles 21 to 24, using only data preceding these cycles, and by analyzing separately two 130 and 140 year-long halves of the original series. We conclude with a prediction of Solar Cycle 25 that can be compared to a dozen predictions by other authors: the maximum would occur in 2026.2 (± 1 yr) and reach an amplitude of 97.6 (± 7.8), similar to that of Solar Cycle 24, therefore sketching a new “Modern minimum”, following the Dalton and Gleissberg minima.

Possible Origin of Some Periodicities Detected in Solar‐Terrestrial Studies: Earth's Orbital Movements

“…Similarly to the Schwabe band, around the Hale band (∼ 22 yr) we found several periods coincidental with periodicities argued to be detected in climatic data series which have also been connected to PH (Scafetta, 2010;Heredia et al, 2019;Courtillot et al, 2021). In particular, Le Mouël et al (2019aMouël et al ( , 2020 have detected specific periodicities at ∼ 22.1 yr and ∼ 21.8 yr in temperature and in aa geomagnetic series, respectively.…”

“…Multi‐year periodicities, such as ∼3.6, ∼4.7, ∼5.5, and 6.5 years periodicity, are argued to be present in terrestrial data series, but were also attributed to the PH (e.g., Courtillot et al., 2021; Le Mouël et al., 2020). Our results show that these periodicities are especially observed in the expansion of : The argument () has a period of 3.98 years, () has a period of 3.59 years; the terms ( j = 104, involving the Moon) and ( j = 107) have similar periods of 4.65 years; the term ( j = 70) has a period of 5.26 years; ( j = 82) has 5.9 years period, etc.…”

“…Multi‐decadal periodicities, such as ∼30, ∼47, and ∼60 years (Courtillot et al., 2021; Le Mouël et al., 2020; Scafetta, 2010), are detected in and variables (ranks 30, 127, 129, and 213) and (ranks 28, 78, 100, and 231). In , we found the 29.5 () and 26 years () periodicities, and the 40.33‐year () periodicity; we cannot observe the ∼47 or ∼60 years periodicities at the j = 250 level of precision.…”

“…The Milanković theory of paleoclimates (Milanković, 1941;Berger et al, 1993) clearly offers a causal link (i.e., insolation variations by orbital changes in ten to hundred thousand years) that permits the attribution of well observed periodicities imprinted in the geologic and oceanic sedimentary records (e.g., Hays et al, 1976;Imbrie, 1982), to long-term oscillations in two specific elements of the relative Earth's orbit around 5.5. yr and ∼ 3.6 yr. Recently, these authors (Courtillot et al, 2021) propose that all of these aforementioned quasi-periods have a planetary origin through the PH. In addition, there are other authors that, on the contrary, have criticized the determinations and/or the attribution of some of the above-mentioned superficial temperature periodicities (especially the 60 yr period), to planetary cycles (see, e.g., Holm, 2014;Cuypers et al, 2021), but their comments have been since replied to (Scafetta, 2016; Le .…”

“…(2019b) detect short periodicities in climatic and geomagnetic indices, identifying periodicities at ∼47, ∼32, ∼22, ∼11 years, ∼9, ∼5.5, and ∼3.6 years. Recently, these authors (Courtillot et al., 2021) propose that all of these aforementioned quasi‐periods have a planetary origin through the PH. In addition, there are other authors that, on the contrary, have criticized the determinations and/or the attribution of some of the above‐mentioned superficial temperature periodicities (especially the 60 years period), to planetary cycles (see e.g., Cuypers et al., 2021; Holm, 2014), but their comments have been since replied to (Le Mouël et al., 2021; Scafetta, 2016).…”