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Quasi-1500-Year-Cycle Signal in Length-of-Day Change Cover

Quasi-1500-Year-Cycle Signal in Length-of-Day Change

By: Lihua MA  
Open Access
|Aug 2021

Abstract

Length-of-day (LOD) change, i.e., variations in Earth’s rotation rate, includes the long-term slowdown trend, as well as periodic and irregular fluctuations. The current continuous sequence of the LOD change covers a time span of <400 years. Using astronomical records in ancient historical documents, combined with a modern astronomical ephemeris, it is possible to obtain ancient LOD change. Some scholars have given a discontinuous LOD data series for the past 4000 years. In this paper, the author uses the Lomb–Scargle periodogram to study the LOD series and finds a significant quasi-1500-year-cycle signal. Furthermore, with weighted wavelet Z-transform, time-varying characteristics of the cycle in the LOD change are obtained.

DOI: https://doi.org/10.2478/arsa-2021-0002 | Journal eISSN: 2083-6104 | Journal ISSN: 1509-3859
Language: English
Page range: 10 - 17
Submitted on: Feb 28, 2021
Accepted on: May 31, 2021
Published on: Aug 13, 2021
Published by: Polish Academy of Sciences, Space Research Centre
In partnership with: Paradigm Publishing Services
Publication frequency: 4 issues per year

© 2021 Lihua MA, published by Polish Academy of Sciences, Space Research Centre
This work is licensed under the Creative Commons Attribution 4.0 License.