Maunder Minimum

[4][5] Because Annie Maunder had not received a university degree, restrictions at the time caused her contribution not to be publicly recognized.

From text of eye-witness reports of events in 1652, 1706 and 1715, he concluded that the solar corona was weak in intensity and unstructured during the Maunder Minimum.

They were painted by a trained and skilful astronomer and observer, Maria Clara Eimmart, the daughter of the director of an observatory housed on a bastion of the walls of Nürnberg castle.

[13] A full discussion of these observations of the Maunder minimum corona and how the K-corona had partially returned by the time of the 1715 event is given by Hayakawa et al.

[12] The Maunder Minimum roughly coincided with the middle part of the Little Ice Age, during which Europe and North America experienced colder than average temperatures.

The scale of changes resulting in the production of carbon-14 in one cycle is small (about one percent of medium abundance) and can be taken into account when radiocarbon dating is used to determine the age of archaeological artifacts.

A paper based on an analysis of a drawing by John Flamsteed suggests that the Sun's surface rotation slowed in the deep Maunder Minimum (1684).

[30][31] This is somewhat surprising because the later, and less deep, Dalton sunspot minimum is clearly seen in auroral occurrence frequency, at least at lower geomagnetic latitudes.

[32] Because geomagnetic latitude is an important factor in auroral occurrence, (lower-latitude aurorae requiring higher levels of solar-terrestrial activity) it becomes important to allow for population migration and other factors that may have influenced the number of reliable auroral observers at a given magnetic latitude for the earlier dates.

[33] Decadal-scale cycles during the Maunder Minimum can also be seen in the abundances of the beryllium-10 cosmogenic isotope (which unlike carbon-14 can be studied with annual resolution)[34] but these appear to be in antiphase with any remnant sunspot activity.

The Maunder Minimum shown in a 400-year history of sunspot numbers
Comparison of group sunspot numbers (top), Central England Temperature (CET) observations (middle) and reconstructions and modeling of Northern Hemisphere Temperatures (NHT). The CET in red are summer averages (for June, July and August) and in blue winter averages (for December of previous year, January and February). NHT in grey is the distribution from basket of paleoclimate reconstructions (darker grey showing higher probability values) and in red are from model simulations that account for solar and volcanic variations. By way of comparison, on the same scales the anomaly for modern data (after 31 December 1999) for summer CET is +0.65 °C, for winter CET is +1.34 °C, and for NHT is +1.08 °C. Sunspot data are as in supplementary data to [ 14 ] and Central England Temperature data are as published by the UK Met Office [ 15 ] The NHT data are described in box TS.5, Figure 1 of the IPCC AR5 report of Working Group 1. [ 16 ]
Solar activity events recorded in radiocarbon.
Graph showing proxies of solar activity, including changes in sunspot number and cosmogenic isotope production.