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Lost sunspot cycle in the beginning of Dalton minimum: New evidence and consequences
Author(s) -
Usoskin I. G.,
Mursula K.,
Kovaltsov G. A.
Publication year - 2002
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2002gl015640
Subject(s) - solar minimum , sunspot , solar cycle , solar cycle 23 , physics , astrophysics , nuclear physics , solar wind , plasma , quantum mechanics , magnetic field
We have recently suggested that one solar cycle was lost in the beginning of the Dalton minimum during 1790s [ Usoskin et al. , 2001]. Earlier, this cycle has been combined with the preceding activity to form the exceptionally long solar cycle 4 in 1784‐1799 with an irregular phase evolution. Here we show that historical data of auroral occurrence provide independent evidence for the existence of the new cycle. Using a heliospheric model we demonstrate that 10 Be or any other cosmogenic isotope data do not exclude the possibility of a new cycle. We also discuss the other implications of the new cycle for solar activity, in particular the cycle length distribution and the Waldmeier relation between the cycle amplitude and the length of the ascending and descending phase. Including the new cycle also restores the Gnevyshev‐Ohl rule of cycle pairing and removes the phase catastrophe in the beginning of the Dalton minimum.