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Author (up) Deng, J.; Wu, Z.; Zhang, M.; Huang, N.E.; Wang, S.; Qiao, F.
Title Data concerning statistical relation between obliquity and Dansgaard-Oeschger events Type $loc['typeJournal Article']
Year 2019 Publication Abbreviated Journal Data Brief
Volume 23 Issue Pages
Keywords Dansgaard-Oeschger events; Obliquity; Surrogate data; Time-varying Shannon entropy
Abstract Data presented are related to the research article entitled “Using Holo-Hilbert spectral analysis to quantify the modulation of Dansgaard-Oeschger events by obliquity” (J. Deng et al., 2018). The datasets in Deng et al. (2018) are analyzed on the foundation of ensemble empirical mode decomposition (EEMD) (Z.H. Wu and N.E. Huang, 2009), and reveal more occurrences of Dansgaard-Oeschger (DO) events in the decreasing phase of obliquity. Here, we report the number of significant high Shannon entropy (SE) (C.E. Shannon and W. Weaver, 1949) of 95% significance level of DO events in the increasing and decreasing phases of obliquity, respectively. First, the proxy time series are filtered by EEMD to obtain DO events. Then, the time-varying SE of DO modes are calculated on the basis of principle of histogram. The 95% significance level is evaluated through surrogate data (T. Schreiber and A. Schmitz, 1996). Finally, a comparison between the numbers of SE values that are larger than 95% significance level in the increasing and decreasing phases of obliquity, respectively, is reported.
Address Key Laboratory of Marine Sciences and Numerical Modelling, Ministry of Natural Resources, Qingdao 266061, PR China
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2352-3409 ISBN Medium
Area Expedition Conference
Funding strtoupper('3').strtolower('1372394'); strtoupper('P').strtolower('MC6660458') Approved $loc['no']
Call Number COAPS @ user @ Serial 1068
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Author (up) Deng, J.; Wu, Z.; Zhang, M.; Huang, N.E.; Wang, S.; Qiao, F.
Title Using Holo-Hilbert spectral analysis to quantify the modulation of Dansgaard-Oeschger events by obliquity Type $loc['typeJournal Article']
Year 2018 Publication Quaternary Science Reviews Abbreviated Journal Quaternary Science Reviews
Volume 192 Issue Pages 282-299
Keywords Pleistocene; Paleoclimatology; Greenland; Antarctica; Data treatment; Data analysis; Dansgaard-oeschger (DO) events; Obliquity forcing; Phase preference; Holo-hilbert spectral analysis; Amplitude modulation; EMPIRICAL MODE DECOMPOSITION; GREENLAND ICE-CORE; NONSTATIONARY TIME-SERIES; ABRUPT CLIMATE-CHANGE; LAST GLACIAL PERIOD; NORTH-ATLANTIC; MILLENNIAL-SCALE; RECORDS; VARIABILITY; CYCLE
Abstract Astronomical forcing (obliquity and precession) has been thought to modulate Dansgaard-Oeschger (DO) events, yet the detailed quantification of such modulations has not been examined. In this study, we apply the novel Holo-Hilbert Spectral Analysis (HHSA) to five polar ice core records, quantifying astronomical forcing's time-varying amplitude modulation of DO events and identifying the preferred obliquity phases for large amplitude modulations. The unique advantages of HHSA over the widely used windowed Fourier spectral analysis for quantifying astronomical forcing's nonlinear modulations of DO events is first demonstrated with a synthetic data that closely resembles DO events recorded in Greenland ice cores (NGRIP, GRIP, and GISP2 cores on GICC05 modelext timescale). The analysis of paleoclimatic proxies show that statistically significantly more frequent DO events, with larger amplitude modulation in the Greenland region, tend to occur in the decreasing phase of obliquity, especially from its mean value to its minimum value. In the eastern Antarctic, although statistically significantly more DO events tend to occur in the decreasing obliquity phase in general, the preferred phase of obliquity for large amplitude modulation on DO events is a segment of the increasing phase near the maximum obliquity, implying that the physical mechanisms of DO events may be different for the two polar regions. Additionally, by using cross-spectrum and magnitude-squared analyses, Greenland DO mode at a timescale of about 1400 years leads the Antarctic DO mode at the same timescale by about 1000 years. (C) 2018 Elsevier Ltd. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0277-3791 ISBN Medium
Area Expedition Conference
Funding Approved $loc['no']
Call Number COAPS @ user @ Serial 971
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