Australia: The Land Where Time Began

A biography of the Australian continent 

The 100,000 Year Problem and the Synchronisation of the Climate System to Eccentricity Forcing

There has been a period of about 100,000 years in the glacial-interglacial cycles over the past million years that is similar to the 100,000-year period of change in the eccentricity of the Earth's orbit. It has been difficult to reconcile the amplitude of the glacial cycles (Lisiecki, 2010; El Kibbi & Rial, 2001; Huybers & Wunsch, 2005; Raymo, 1997; Berger, Melice & Loutre, 2005) to the changing insolation as a result of this small timescale. Known as the 100-kyr problem, a lack of explanation for the transition of cycle length, from 41,000 to 100,000 years, 1.2 Ma at the mid-Pleistocene transition has compounded the problem(Clark et al., 2006). Interactions between other orbital frequencies, such as the obliquity and the 413,000-year eccentricity period (Huybers & Wunsch, 2005; Raymo, 1997; Berger, Melice & Loutre, 2005; Clark et al., 2006; Saltzman, 2002; Rial, 1999; Pisias & Moore, 1981; Paillard, 1998; Muller & McDonald, 2000; Oerlemans, 1984; Tziperman et al., 2006), as well as other individual discrepancies, have been explained, though there remains a lack of a unifying explanation. In this study the authors1 have shown that over the past 4 million years the oscillations of climate can be explained by a single mechanism - the synchronisation of non-linear internal climate oscillations and the eccentricity cycle of 413,000 years. The authors1 found, by the use of spectral analyses, aided by a numerical model, that about 1.2 Ma the climate system first synchronised to the 413,000-year cycle of eccentricity, which has remained the case up to the present. The amplitude of the 100,000-year cycle increases as a result of this synchronisation, the result of which is a transfer of power and frequency modulation The conclusion reached by the authors1 is that the strong 100,000-year glacial cycles can be explained by the forced synchronisation through the alignment of changes of insolation and internal climate oscillations.

 

Sources & Further reading

  1. Rial, Jose A., Jeseung Oh, and Elizabeth Reischmann. "Synchronization of the Climate System to Eccentricity Forcing and the 100,000-Year Problem." Nature Geosci 6, no. 4 (04//print 2013): 289-93.

 

Author: M. H. Monroe
Email: admin@austhrutime.com
Last updated: 04/04/2013
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                                                                                           Author: M.H.Monroe  Email: admin@austhrutime.com     Sources & Further reading