Climate of the Past Discussions www.clim-past-discuss.net 1814-9340 1814-9359 5 1 2009 10.5194/cpd-5-327-2009 http://www.clim-past-discuss.net/5/327/2009/ http://www.clim-past-discuss.net/5/327/2009/cpd-5-327-2009.html http://www.clim-past-discuss.net/5/327/2009/cpd-5-327-2009.pdf 327 340 2009-02-09 Astronomical forcing and mathematical theory of glacial-interglacial cycles A. V. Kislov avkislov@mail.ru Moscow State University, Moscow, Russia There are three important features of a proxy time series recorded during the Late Pleistocene. They are: 1) 100 000-year cycle as a dominant control of global glacial-interglacials through the late Quaternary, 2) fluctuations with periods of about 40 and 20 thousand years (their contribution to dispersion is no more than 20%), 3) ''Red-noise'' behavior of the time series. Direct influence of the insolation change created by fluctuations of the eccentricity is too weak to cause the observed 100 000-year climate fluctuations. Therefore, other mechanisms of such a rhythm are proposed. On the basis of the equation of the heat budget, the equation describing dynamics of zonally averaged temperature is developed. Various combinations of terms of this equation are discussed. They present a linear response to the Milankovitch periodicity, the Langeven stochastic equation, the equation of delay oscillator, the stochastic equation of spontaneous transitions, and the equation of stochastic resonance. <br><br> Orbitally-induced changes in the solar energy flux received by the Earth play an important role as a mechanism starting process of climate changes which is supported and intensified by different feedbacks within the climate system. Positive anomalies of solar radiation serve as a mechanism causing reorganization of the climate only in rare cases when inclination of Earth axis of rotation increases and, simultaneously, perihelion takes place during the summer time (for the Northern Hemisphere). Anishchenko, V S., Neiman, A B., Moss, F., and Shimansky-Geier, L.: Stochastic resonance: noise-enhanced order, Phys.-Usp, 42, 7–36, 1999. Benzi, R., Parisi, G., Sutera, A., and Vulpiani, A.: Stochastic resonance in climatic change, Tellus, 34, 10–18, 1982. Berger, A.: Long-term variations of daily insolation and Quaternary climate changes, J. Atmos. Sci., 35, 2362–2367, 1978. Berger, A., Loutre, M F., and Melice, J L.: Instability of the astronomical periods from 1.5 \unitmyr BP to 0.5 \unitmyr AP, Paleoclimates, 2(4), 239–280, 1998. Bintanja, R. and van de Wal, R S W.: North American ice-sheet dynamics and the onset of 100,000-year glacial cycles, Nature, 454, 869–872, 2008. Crucifix, M.: Global change: Climate's astronomical sensors, Nature, 456, 47–48, 2008. Hasselmann, K.: Stochastic climate models, Tellus, 28, 473–485, 1976. Hayes, J D., Imbrie, J., and Shacklton, N J.: Variation in the Earth's orbit: pacemaker of the ice ages, Science, 194, 1121–1132, 1976. Imbrie, J., Hays, J., Martinson, D J., et al.: The orbital theory of Pleistocene climate: support from a revised chronology of the marine 180 record, in: Milankovitch and Climate, edited by: Berger, A., Imbrie, J., Hays, J., Kukla, G., and Saltzman B., The Netherlands: Reidel Publishing, Dordrecht, 269–305. 1984. Joussaume, S.: Modeling extreme climates of the past 20,000 \unityr with general circulation models, in: Modeling the Earth's climate and its variability, edited by: Holland, W R., Joussaume, S., and David, F., Elsevier, Amsterdam and New York, 527–565, 1999. Kislov, A V., Tarasov, P E., and Sourkova, G V.: Pollen and other proxy-based reconstructions and PMIP simulations of the Last Glacial Maximum mean annual temperature: an attampt to harmonize the data – model comparison procedure, Acta Palaeontol. Sin., 41, 539–545, 2002. Kominz, M A. and Pisias, N G.: Pleistocene climate: deterministic or stochastic? Science, 204, 171–173, 1979. Nicolis, C.: Stochastic aspects of climatic transitions – response to a~periodic forcing, Tellus, 34, 1–9, 1982. Schlesinger, M E. and Verbitsky, M.: Simulation of glacial onset with a~coupled atmospheric general circulation/mixed-layer ocean – ice-sheet/astenosphere model, Palaeoclimates, 2, 179–201, 1996. Wiesenfeld, K. and Moss, F.: Stochastic resonance and the benefits of noise: from ice ages to crayfish and SQUIDs, Nature, 373, 33–36, 1995. Wunsch, C.: The spectral description of climate change including the 100 \unitky energy, Clim. Dynam., 20, 353–363, 2003.