Astronomical cycles in quaternary climatic data
Berger, A. (1990). Astronomical cycles in quaternary climatic data, in: UniversiTECH 90: Remote sensing techniques and global change research. Seminar 30-31 March 1990. pp. 1 In: (1990). UniversiTECH 90: Remote sensing techniques and global change research. Seminar 30-31 March 1990. Vrije Universiteit Brussel: Brussel. 6 p. abstracts, 19 p. pp., more |
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| Abstract | Spectral analysis of geological records show periodicities corresponding tothose calculated for the eccentricity (400 and 100 ka), the obliquity (41 ka) and the climaticprecession (23 and 19ka). It is precisely the geological observations of this bi -partition ofthe precessional peak, confIrmed to be real in astronomical computations, which was one ofthe most impressive of all tests for the Milankovitch theory. Concerning the question ofwether or not the observed cycles account for most of the climatic variability having periodsin the range predicted by the astronomical theory, substantial evidence (from cross - spectralanalysis, coherency analysis, and modelling) is provided that, at least near frequencies ofvariation in obliquity and precession, a considerable fraction of the climate variance is drivenin some way by insolation changes accompanying changes in the earth's orbit. The variancecomponents centered near a 100 ka cycle dominate most ice volume records and seem inphase with the eccentricity cycle, although the exceptional strenght of this cycle needs a non -linear amplification by the glacial ice sheets themselves and associated feedbacks. |
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