12th Workshop Solar Influences...

Tsvetkov, Ts.; Petrov, N.; Miteva, Rositsa; Ivanov, Emil; Popov, V.

doi:10.31401/ws.2020.proc

Cited by 2 publications

(1 citation statement)

References 146 publications

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“…It is interesting also to note some extremely powerful SEP events in the past (most probably near to 11 year sunspot maxima epochs), which seriously affected the GCR -flux during the corresponding calendar epochs (in 665-663 BC, 775 AD, and 993 AD). They are detected on the basis of high precise mass-spectrometric measurements of 14 C tree rings concentrations [75][76][77].…”

Section: Discussionmentioning

confidence: 99%

The European Beech Annual Tree Ring Widths Time Series, Solar–Climatic Relationships and Solar Dynamo Regime Changes

Komitov

2021

Atmosphere

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In this study, the results from the analysis of annual ring widths (‘Dm’) time series of two “very sensitive” to the climate and solar–climate relationships of long lived European beech (Fagus sylvatica) samples (on age of 209 ± 1 and 245 ± 5 years correspondingly) are discussed. Both series are characterized by very good expressed and relating to the solar magnetic Hale cycle 20–22-year oscillations. A good coincidence between the changes of ‘Dm’ and the growth or fading of the solar magnetic cycle is found. The transition effects at the beginning and ending of the grand Dalton (1793–1833) and Gleissberg minima (1898–1933) are very clearly visible in the annual tree ring width data for the one of beech samples. Some of these effects are also detected in the second sample. The problem for the possible “lost” sunspot cycle at the end of 18th century is also discussed. A prediction for a possible “phase catastrophe” during the future Zurich sunspot cycles 26 and 27 between 2035–2040 AD as well as for general precipitation upward and temperature fall tendencies in Central Bulgaria, more essential after 2030 AD, are brought forth.

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Section: Discussionmentioning

confidence: 99%

The European Beech Annual Tree Ring Widths Time Series, Solar–Climatic Relationships and Solar Dynamo Regime Changes

Komitov

2021

Atmosphere

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"Danjon Effect", Solar-Triggered Volcanic Activity, and Relation to Climate Change

Komitov

Кафтан

2022

Russian Journal of Earth Sciences

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The “Danjon effect” is a phenomenon that presents a tendency to concentrate the so-called “dark” total lunar eclipses (DTLE) near solar sunspot cycle minimum phases. It was a starting point for the present study, whose main subject is a statistical analysis of relationship between solar and volcanic activity for the maximum long time. To this end, the Smithsonian National Museum of Natural History's volcanic activity catalog was used. On its basis, a time series of the total annual volcanic eruptions for the period 1551–2020 AD has been built and explored for cycles of possible solar origin. Cycles with duration of 10–11, 19–25, ∼60, and ∼240 years (all with possible solar origin) has been established. It has also been found that there are two certain peaks of volcanic activity during the sunspot activity cycle: the first one is close to or after the sunspot minimum (sunspot cycle phase 0.9 ≤ Φ ≤1.0 and 0.1 ≤ Φ ≤ 0.2), and the second is wider – close to the sunspot cycle maximum (0.3 ≤ Φ ≤ 0.5). A third maximum is detected about 3–4 years after the sunspot cycle maximum (0.7 ≤ Φ ≤ 0.8) for the “moderate strong” volcanic eruptions with volcanic eruptive index VEI = 5. It corresponds to the geomagnetic activity secondary maximum, which usually occurs 3–4 years after the sunspot maximum. Φ is calculated separately on the basis of each sunspot cycle length. Finally, without any exclusions, all most powerful volcanic eruptions for which VEI ≥ 6 are centered near the ∼11-year Schwabe-Wolf cycle extremes. Trigger mechanisms of solar and geomagnetic activity over volcanic events, as well as their relation to climate change (in interaction with galactic cosmic rays (GCR) and/or solar energetic particles (SEP)), are discussed. The Pinatubo eruption in 1991 as an example of a “pure” strong solar–volcanism relationship has been analyzed in detail.

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12th Workshop Solar Influences...

Cited by 2 publications

References 146 publications

The European Beech Annual Tree Ring Widths Time Series, Solar–Climatic Relationships and Solar Dynamo Regime Changes

The European Beech Annual Tree Ring Widths Time Series, Solar–Climatic Relationships and Solar Dynamo Regime Changes

"Danjon Effect", Solar-Triggered Volcanic Activity, and Relation to Climate Change

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