The findings of an investigation of yearly ring widths ('Dm') time series of two "extremely sensitive" to climate and solar–climate correlations of long lived European beech (Fagus sylvatica) samples (on ages of 209 1 and 245 5 years, respectively) are addressed in this work. Both series have excellent expression and are related to the 20–22-year solar magnetic Hale cycle oscillations. There is a strong correlation between changes in 'Dm' and the expansion or fading of the solar magnetic cycle. In the annual tree ring width data for one of the beech samples, the transition effects at the beginning and end of the great Dalton (1793–1833) and Gleissberg minima (1898–1933) are very clearly obvious. Some of these impacts can be seen in the second sample as well. Also mentioned is the issue of a possibly "lost" sunspot cycle near the end of the 18th century. A possible "phase catastrophe" is predicted for the future Zurich sunspot cycles 26 and 27 between 2035 and 2040 AD, as well as general precipitation increase and temperature decrease trends in Central Bulgaria, which will become increasingly important from 2030 AD. The given kinematic models of tree ring widths time series, as well as the extrapolated data, support the idea that grand solar minima are better characterised as quasi regular rather than stochastic events.
Author(S) Details
Boris Komitov
Institute of Astronomy and NAO-Bulgarian Academy of Sciences, 1784 Sofia, Bulgaria.
View Book:- https://stm.bookpi.org/CAGEES-V1/article/view/5188
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