Long-term solar activity variations as a stimulator of abrupt climate change

O. M. Raspopov1, A. V. Dergachev2, T. Kolström3, A. V. Kuzmin4, E. V. Lopatin3,5, and O. V.  Lisitsyna6

1St.Petersburg Filial of Pushkov Institute of Terrestrial Magnetism, Ionosphere, and Radiowave Propagation of RAS, St.Petersburg, Russia
2Ioffe Physico-Technical Institute of RAS, St.Petersburg, Russia
3Mekrijärvi Research Station, University of Joensuu, Joensuu, Finland
4Polar Botanical Garden-Institute KolaSC RAS, Kirovsk, Murmansk Region, Russia
5Biology Institute of KomiSC of Ural Branch, RAS, Syktyvkar, Russia
6Oulu University, Oulu, Finland


[1]  Analysis of solar forcing of climate on long time scales has shown that it is necessary to take into consideration the influence of long-term solar cyclicity, such as 200 and 2300-2400-year cycles, on climate. Even in the relatively warm climate of the last 10,000 years, a tendency to climate cooling at deep minima of long-term solar cyclicity is observed. Along with this, a long-term solar forcing of climate manifests itself not only as an external factor due the influence of solar irradiance variations on the atmosphere-ocean system, but also as a stimulator of internal processes in the climatic system, which, in turn, can lead to abrupt climate change. Large-scale abrupt climate oscillations - warmings and subsequent coolings (Dansgaard-Oeschger cycles) - have been revealed in cores of Greenland ice for the interval 60,000-10,000 years BP. They are attributed to the ice-rafting events in the North Atlantic. A comparative analysis of the development of Dansgaard-Oeschger events and solar activity variations (variations in the 10Be concentration in Greenland ice) has shown that these climatic and solar processes developed simultaneously. It is evident that ice-rafting events were stimulated by an increasing ambient temperature and, hence, they are associated with a high solar activity level. A similar effect of solar activity has been revealed for the time interval of the Holocene. Thus, not only a low, but also a high level of solar activity was in the past a stimulator of abrupt climate changes.

Received 20 October 2007; accepted 18 November 2007; published 15 December 2007.

Keywords: solar activity variations, abrupt climate change, ice-rafting events.

Index Terms: 1616 Global Change: Climate variability; 1650 Global Change: Solar variability; 7536 Solar Physics, Astrophysics, and Astronomy: Solar activity cycle.


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