Materials of the International Conference
50th Anniversary of the International Geophysical Year
and Electronic Geophysical Year

16-19 September 2007 • Suzdal, Russia

Long-term solar activity variations as an impetus for sharp climatic changes

O. M. Raspopov1 and V. A. Dergachev2

1St. Petersburg Filial (Branch) of Pushkov Institute of Terrestrial Magnetism, Ionosphere, and Radiowave Propagation of RAS, St. Petersburg, Russia

2Ioffe Physical and Technical Institute of RAS, St.Petersburg, Russia

Abstract

Analysis of the effect of solar activity variations on climatic processes at long time scales has revealed that long-term solar cyclicities, such as 200 and 2300–2400-year cycles inferred from cosmogenic isotopes, give rise to sharp climatic changes. A tendency to cooling during deep solar minima is observed even for a relatively warm climate of the last 10,000 years. Along with this, long-term solar forcing of climate manifests itself not only as an external factor, due to variations in solar irradiance, of the atmosphere-ocean system but also as a stimulator of internal processes in the system which, in turn, can lead to sharp climate changes. Large-scale sharp climatic oscillations – warmings and subsequent coolings (Dansgaard-Oeschger cycles) have been inferred from the data on the Greenland ice cores for the interval 60,000–20,000 years ago. They are attributable to large-scale discharge of ice masses into the North Atlantic. A comparative analysis of development of Dansgaard-Oeschger events and solar activity variations (changes in the 10Be concentration in Greenland ice) has shown that the climatic and solar events mentioned above developed simultaneously. It is evident that discharge of ice masses was stimulated by an increase in the ambient temperature and, hence, was associated with a low solar activity level. Thus, not only a high but also a low solar activity level gave an impetus to sharp climate changes in the past.

Citation: O. M. Raspopov and V. A. Dergachev (2007), Long-term solar activity variations as an impetus for sharp climatic changes, in: Materials of the International Conference '50th Anniversary of the International Geophysical Year and Electronic Geophysical Year', GC RAS, Moscow, doi:10.2205/2007-IGY50conf.

© 2007 Geophysical Center RAS and authors


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