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Long-term Solar Variability and the Solar Cycle in the 21 st Century. Zasshikai short talk. Boncho P. Bonev , Kaloyan M. Penev , and Stefano Sello ApJ 605, L81, 2004. 1. Introduction. Variation of the soar activity 11 year cycle Maunder minimum From 1600AD to 1700AD Long-term variation
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Long-term Solar Variability and the Solar Cycle in the 21st Century Zasshikai short talk Boncho P. Bonev , Kaloyan M. Penev , and Stefano Sello ApJ 605, L81, 2004
1. Introduction • Variation of the soar activity • 11 year cycle • Maunder minimum • From 1600AD to 1700AD • Long-term variation • Gleissberug period (from optical solar record) • T = 80-90 years 100 years (from recent analysis) • Suess cycle (from aurora record) • T = quasi 200 years • Solar activity forecast ?
2. The Time Series Analyzed 1. The 14C radiocarbon data • 4500 years span, 10 years step • Dendrochronology 2. The Schove series (aurora data) • 1700 years span from 296AD • Quasi 200 year cycle • (Activity in odd century) < (even century) during the past millennium 3. The Group Sunspot Number (GSP) • 400 years span from 1610AD • RG = 12.08/N ∑ki Gi • Gi : number of sunspot group, ki : correction factor N : number of observer, i : observer index
Fig.1 14C data M : Maunder Minimum Large Δ14C value low solar activity
Schove series (aurora) (Komitov & Bonev, ApJ 554, L119, 2001)
Group Sunspot Number (GSN) GSN Wolf (Hoyt & Schatten, SolPyhs, 181, 491, 1998)
3. Approach • Fast-Moving Window Periodogram Algoritm (MWPA) • 800 years subset • Multiresolution Wavelet Analysis (WA)
Fig. 2-1 WA result for 14C data Regime 2 Regime 1 Regime 2 Regime 1
Regime 1 M : Maunder Minimum Large Δ14C value low solar activity
4.2 Two Regimes of the Long-Term Solar Variability • Regime 1 • Strong quasi 200 years cycle • Strognly suppressed 100 years cycle • (130-150 year cycle) • Regime 2 • low 200 year cycle • Unstable and weak 100 year cycle • Schove series (aurora) is very similar to 14C data
4.3 Synthesis • Regime 1 • 210 years cycle • Low activity (Maunder type) • Regime 2 • Overall active
4.3 Synthesis (continue 1) • On the longer time scale • After Maunder Minimum • Weak 200 year cycle • Activity was highest in the middle of 20th century • Changing from regime 1 to 2 ? • On the shorter time scale • Now in the minimum phase of 100 year cycle • In the declining phase of 200 year cycle • Untypical behavior of solar cycle 23 against the Gnevyshev-Ohl rule (the cycle 23 was magnetically weaker than the cycle 22)
4.3 Synthesis (continue 2) • Long-term minimum in the next several decades • Less deep than the Maunder Minimum ?