The Maunder minimum (1645–1715) was indeed a grand minimum: A reassessment of multiple datasets

Abstract

Aims. Although the time of the Maunder minimum (1645-1715) is widely known as a period of extremely low solar activity, it is still being debated whether solar activity during that period might have been moderate or even higher than the current solar cycle #24. We have revisited all existing evidence and datasets, both direct and indirect, to assess the level of solar activity during the Maunder minimum. Methods. We discuss the East Asian naked-eye sunspot observations, the telescopic solar observations, the fraction of sunspot active days, the latitudinal extent of sunspot positions, auroral sightings at high latitudes, cosmogenic radionuclide data as well as solar eclipse observations for that period. We also consider peculiar features of the Sun (very strong hemispheric asymmetry of the sunspot location, unusual differential rotation and the lack of the K-corona) that imply a special mode of solar activity during the Maunder minimum.Results. The level of solar activity during the Maunder minimum is reassessed on the basis of all available datasets. Conclusions. We conclude that solar activity was indeed at an exceptionally low level during the Maunder minimum. Although the exact level is still unclear, it was definitely lower than during the Dalton minimum of around 1800 and significantly below that of the current solar cycle #24. Claims of a moderate-to-high level of solar activity during the Maunder minimum are rejected with a high confidence level.

Supermodulation of the Sun's magnetic activity: the effects of symmetry changes

“…Weiss 1985Weiss , 2010. The earliest telescopic observations of sunspots in the seventeenth century revealed considerable activity, which was interrupted by the Maunder Minimum (Eddy 1976;Thomas & Weiss 2008), as recently confirmed by the detailed study of Usoskin et al (2015). Proxy measurements of the abundances of the cosmogenic isotopes 14 C (in tree rings) and 10 Be (in polar ice cores) confirm that similar grand minima have recurred aperiodically over the past 10,000 years (e.g.…”

Assessment of different sunspot number series using the cosmogenic isotope 44 Ti in meteorites

“…The error bars represent the statistical errors of measurements (1σ ). We note that this data set is updated, including more data points, with respect to earlier studies Usoskin et al 2006;Usoskin et al 2015). We used this data set to test different SN scenarios by applying the method developed by Usoskin et al (2006).…”

“…However, this method can be hardly applied for the 20th century because of the anthropogenic effects (fossil fuel burning, land-use changes and atmospheric nuclear bomb tests) and climate changes that affect the cosmogenic isotope transport and deposition. As a result, applications of the cosmogenic isotope data to assess quality of different SN reconstructions were also inconclusive and contradictory; Muscheler et al (2016) found, using an ad hoc normalization, that the high SN series agree with the cosmogenic record, but they did not analyse other sunspot series; Usoskin et al (2015) concluded that while low SN series agree with the cosmogenic 14 C data, the high series do not; Owens et al (2016b) suggested that all SN series agree more or less with cosmogenic 10 Be data, within the uncertainties. Probably, such ambiguity of the results is related to the fact that changes in the solar activity are governed by the 11-yr cycle that is, of course, synchronous in all the SN reconstructions, with the only difference being in the amplitude.…”

The Maunder minimum and the Little Ice Age: an update from recent reconstructions and climate simulations

“…The Maunder minimum is the most recent grand minimum of solar activity (Usoskin et al, 2015;Usoskin, 2017). In the solar and space physics literature it is often assumed the MM is contemporaneous with, and sometimes even directly causative of, the LIA, a cooler period in Europe and/or the northern hemisphere.…”

“…Solar activity reconstructions based on cosmogenic radionuclide data, such as 14C, 10Be and 44Ti, show that Schwabe cycles are modulated by much longer-term variations, resulting in grand maxima and grand minima of activity (Usoskin, 2017). The Maunder minimum (MM), AD 1645-1715 (Eddy, 1976;Usoskin et al, 2015), is the most recent grand minimum and the only one covered by telescopic sunspot observations. It is thus of great interest to solar dynamo, space weather and terrestrial climate studies.…”