Ilya Usoskin, Mr. - Prof.
Sodankylä Geophysical Observatory, University of Oulu, Finland
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Session 4 - Invited Speaker

Long term solar activity

I. Usoskin, Sodankylä Geophysical Observatory, University of Oulu, Finland
       

A review of the solar variability on long-term scale (from a decade to several millennia) is presented. The last 400 years are covered by direct solar observations in the form of sunspot counts but is it representative for the overall solar variability? For longer time scale, up to ten millennia, we use indirect proxies, such as cosmogenic radionuclides (14C and 10Be) stored in stratified natural archives. Uncertainties of the solar activity reconstructions are discussed. Special attention is paid upon the occurrence of Grand minima and maxima of solar activity.