<abstract xmlns="http://www.w3.org/1999/xhtml">

<p>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 &lt;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 Using astronomical records in ancient historical documents, combined with a modern astronomical ephemeris, it is possible to obtain ancient LOD change.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.</p>
</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 Using astronomical records in ancient historical documents, combined with a modern astronomical ephemeris, it is possible to obtain ancient LOD change.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.

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

Artificial Satellites

This work is licensed under the Creative Commons Attribution 4.0 International License.

{"article-title":"Quasi-1500-Year-Cycle Signal in Length-of-Day Change"}

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....

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

Published Online: Aug 13, 2021

Page range: 10 - 17

Received: Feb 28, 2021

Accepted: May 31, 2021

DOI: https://doi.org/10.2478/arsa-2021-0002

Keywords
length-of-day change, Lomb–Scargle periodogram, weighted wavelet Z-transform

© 2021 Lihua MA, published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 International License.

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

Published Online: Aug 13, 2021

Page range: 10 - 17

Received: Feb 28, 2021

Accepted: May 31, 2021

DOI: https://doi.org/10.2478/arsa-2021-0002

Keywordslength-of-day change, Lomb–Scargle periodogram, weighted wavelet Z-transform

© 2021 Lihua MA, published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 International License.

Keywords
length-of-day change, Lomb–Scargle periodogram, weighted wavelet Z-transform