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DOI	10.5194/cp-15-1959-2019
	Bispectra of climate cycles show how ice ages are fuelled
	Liebrand D.; De Bakker A.T.M.
发表日期	2019
ISSN	18149324
起始页码	1959
结束页码	1983
卷号	15 期号:6
英文摘要	The increasingly nonlinear response of the climate-cryosphere system to insolation forcing during the Pliocene and Pleistocene, as recorded in benthic foraminiferal stable oxygen isotope ratios (d18O), is marked by a distinct evolution in ice-age cycle frequency, amplitude, phase, and geometry. To date, very few studies have thoroughly investigated the non-sinusoidal shape of these climate cycles, leaving precious information unused to further unravel the complex dynamics of the Earth's system. Here, we present higher-order spectral analyses of the LR04 d18O stack that describe coupling and energy exchanges among astronomically paced climate cycles. These advanced bispectral computations show how energy is passed from precession-paced to obliquity-paced climate cycles during the Early Pleistocene (from ĝ'1/42500 to ĝ'1/4750 ka) and ultimately to eccentricity-paced climate cycles during the Middle and Late Pleistocene (from ĝ'1/4750 ka onward). They also show how energy is transferred among many periodicities that have no primary astronomical origin. We hypothesise that the change of obliquity-paced climate cycles during the mid-Pleistocene transition (from ĝ'1/41200 to ĝ'1/4600 ka), from being a net sink into a net source of energy, is indicative of the passing of a land-ice mass loading threshold in the Northern Hemisphere (NH), after which cycles of crustal depression and rebound started to resonate with the ĝ'1/4110 kyr eccentricity modulation of precession. However, precession-paced climate cycles remain persistent energy providers throughout the Late Pliocene and Pleistocene, which is supportive of a dominant and continuous fuelling of the NH ice ages by insolation in the (sub)tropical zones, and the control it exerts on meridional heat and moisture transport through atmospheric and oceanic circulation. . © Author(s) 2019.
语种	英语
scopus关键词	climate variation; cryosphere; eccentricity; hypothesis testing; insolation; paleoclimate; Pleistocene; Pliocene-Pleistocene boundary; spectral analysis
来源期刊	Climate of the Past
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/146768
作者单位	Center for Marine Environmental Sciences (MARUM), University of Bremen, Bremen, Germany; LIttoral ENvironnement et Sociétés (LIENSs), Université de La Rochelle, La Rochelle, France; Unit of Marine and Coastal Systems, Deltares, Delft, Netherlands
推荐引用方式 GB/T 7714	Liebrand D.,De Bakker A.T.M.. Bispectra of climate cycles show how ice ages are fuelled[J],2019,15(6).
APA	Liebrand D.,&De Bakker A.T.M..(2019).Bispectra of climate cycles show how ice ages are fuelled.Climate of the Past,15(6).
MLA	Liebrand D.,et al."Bispectra of climate cycles show how ice ages are fuelled".Climate of the Past 15.6(2019).