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Multidecadal and 6-year variations of LOD
Ch. 5. P. 1–17.
The subject of our study is 6-, 20- and 60-year oscillations in the length of day (LOD). Spectral and wavelet analyses of LOD time series have been performed, multidecadal harmonics have been adjusted and simple prediction has been made. Input from the variations of the angular momentum of the ocean and the atmosphere into LOD changes at 6-, 20- and 60-year periods has been analysed. We found out that the oceanic forcing (OAM) of LOD at 20- and 60-year scales is less than 20 microseconds, and 6-year oscillation after atmospheric effects subtraction becomes quite stable with the amplitude of around 0.2 milliseconds. To perform filtering, we used Panteleev's band-pass filter. Since multidecadal oscillations with the amplitude up to 3 milliseconds remain unexplained, we compared them with temperature and sea level anomalies, Chandler wobble and its excitation envelope, and with the Earth's magnetic dipole strength anomaly, a number of processes contain multidecadal variations, the signature of which is quite similar to LOD changes.
Publication based on the results of:
In book
IOP Publishing, 2020.
Zotov L., Sidorenkov N., Bizouard C., , in: Proceedings of the 19th Annual Meeting ofthe Asia Oceania Geosciences Society.: Singapore: World Scientific Publishing Co. Pte. Ltd, 2023. P. 153–155.
In early 2000-s the amplitude of the Chandler wobble (CW) started to decrease and in 2017-2020 reached its historic minima, comparable only with the minima of ~1928 yr. In 2021 the CW appeared again. We demonstrate that the phase of the CW is changing now, as during 1920-1930s. Since 2010 it has changed almost by ...
Added: March 5, 2026
Zotov L., Sidorenkov N., Bizouard C., , in: Proceedings of the XV Conference and School (St. Petersburg, Russia, April 22–26). Problems of Geocosmos—2024.: Switzerland: Springer, 2026. P. 289–312.
Earth rotation in recent epoch shows anomalies: its rotation velocity reached decadal maximum in 2024; the Chandler wobble (CW) of the rotation axis disappeared in 2018–2020, then resumed with a phase changed by 180^\circ
◦; the ampli-tude of the Free Core Nutation (FCO) decreased since 2021 as well. We analyzed the CW amplitude modulations since the ...
Added: March 1, 2026
Zotov L., Логинов А. В., Ольховский А. А. et al., В кн.: ВОПРОСЫ ТЕОРИИ И ПРАКТИКИ ГЕОЛОГИЧЕСКОЙ ИНТЕРПРЕТАЦИИ ГРАВИТАЦИОННЫХ, МАГНИТНЫХ И ЭЛЕКТРИЧЕСКИХ ПОЛЕЙ 51-я сессия Международного семинара им. Д.Г. Успенского - В.Н. Страхова. Москва, 2025.: Пермский государственный университет, 2025.
One of the major components of the Earth’s polar motion is Chandler wobble with 433-day period. To extract it from observations narrow-band filtering is required. We have developed method which joins Kalman filtering and band-pass filtering in direct time with the phase correction in reversed time. By using Euler-Liouville equation generating resonant CW as a ...
Added: December 10, 2025
Zotov L., Юшкин В. Д., Фролова Н. Л. et al., , in: Информационные технологии и нанотехнологии (ИТНТ-2024). сборник трудов по материалам X Международной конференции и молодежной школы: в 6 томах.: Самарский государственный университет, 2024. P. 22002–22004.
The GRACE and GRACE-FO satellites provide data on the Earth's gravitational field changes and are among the most successful NASA/DLR geodetic missions in recent decades. Based on their data, the melting of glaciers, redistribution of masses in the river basins, and changes in the ocean mass are studied. We use multichannel singular spectral analysis (MSSA) ...
Added: May 30, 2025
Abrashkin A. A., World Scientific Publishing Co. Pte. Ltd, 2025.
This book is devoted to the problems of the analytical description of incompressible fluid flows in Lagrangian variables. Commonly, specialists in fluid dynamics prefer to use the Euler approach. For example, even classical textbooks by J. Batchelor, L.G. Loitsyansky, L.D. Landau, and E.M. Lifshitz do not provide the Lagrange equations of f luid dynamics. Exceptions ...
Added: January 28, 2025
Zotov L., Сидоренков Н. С., Марчукова О. В. et al., В кн.: ВОПРОСЫ ТЕОРИИ И ПРАКТИКИ ГЕОЛОГИЧЕСКОЙ ИНТЕРПРЕТАЦИИ ГРАВИТАЦИОННЫХ, МАГНИТНЫХ И ЭЛЕКТРИЧЕСКИХ ПОЛЕЙ 50-я юбилейная сессия Международного семинара им. Д.Г. Успенского - В.Н. Страхова. Москва, 2024.: М.: Издательство "Перо", 2024. С. 162–166.
Since strong El Nino 2016 the tendency of acceleration of the Earth rotation has been observed. In 2022 the Earth rotation velocity reached maxima comparable with those happened 90 years ago. Triplet of La Nina accompanied this case. Chandler wobble of the pole almost disappeared in 2017-2020, which was earlier observed only in the end ...
Added: March 1, 2024
Zotov L., Industry 4.0 2023 Vol. 8 No. 5 P. 166–168
In 2022 the Erath rotation velocity reached its maximum and in 2017-2020 the Chandler wobble of the rotational axis disappeared for the second time in the history of observations. Unexplained modulations of 90 and 20-25 year periods are observed. They reflect geophysical processes in the atmosphere, ocean, and Earth’s interior and can be linked to ...
Added: February 10, 2024
Zotov L., Сидоренков Н. С., Бизуар К., Вестник Московского университета. Серия 3: Физика и астрономия 2022 № 3 С. 64–72
The Earth’s rotation is nonuniform: the position of the pole drifts and describes circles with the annual and Chandler (433 days) periods; the Earth’s rotation velocity also varies. In the beginning of 2000s, the amplitude of the Chandler wobble began to decrease and in 2017–2020 reached a historical low comparable only with the low of ...
Added: October 25, 2022
Bizouard C., Fernandes L., Zotov L., Journal of Geophysical Research: Solid Earth 2022 Vol. 127 No. 3 Article e2021JB022962
This study is devoted to the determination of the admittance parameters describing the Earth
rotational response to the components of the zonal tide potential. First, in order to better grasp the physical
content of those admittance coefficients, we revisit the theoretical description of the length of day (LOD)
changes at sub-decadal time scale, where forcing is dominated by ...
Added: April 5, 2022
Zotov L., НИУ ВШЭ, 2022.
The work is devoted to the consideration of geophysical processes that cause the motion of the pole and changes in the length of the day. Particular attention is paid to the Chandler wobble. The method of its extraction and geodesic excitation reconstruction is developed. Atmospheric and oceanic excitation functions are investigated in the Chandler frequency ...
Added: December 7, 2021
Zotov L., Bizouard C., Shum C. K. et al., Advances in Space Research 2022 Vol. 69 No. 1 P. 308–318
We analyzed the impacts of data span on trend estimates using Earth’s long-term polar motion time series, 1846-present, and using methodologies including singular spectrum analysis, and Panteleev’s filter to mitigate the time series containing transient signals. Our results show that the fluctuations of the mean rotational pole position, the Markowitz wobble, cannot be fully explained ...
Added: October 22, 2021
Zotov L., Bizouard C., Природа 2021 № 3 С. 26–29
2020 has been recognized by the scientific climate community as one of the hottest on the planet in recent decades. Also an anomalous acceleration in
the rotation of the Earth was observed during this year. The length of the day has reached its minimum. The article discusses the factors influencing the
rotation of the Earth, their possible ...
Added: April 15, 2021
Zotov L., Устинов А. А., В кн.: Сборник тезисов докладов конференции КИМО-2020.: [б.и.], 2020.
Особенности вращения Земли, такие как вариации длительности суток и отклонения в движении полюса наблюдаются уже более века. Анализ временных рядов, предоставляемых международной службой вращения Земли показывает наличие квази- 20-, 40- и 60-летних колебаний в них. Являясь откликом на процессы в океане, атмосфере и недрах Земли, будучи следствием обмена угловым моментом между этими оболочками, вариации вращения ...
Added: December 7, 2020
Сидоренков Н. С., Dionis E., Bizouard C. et al., , in: Proceedings of Journees 2019.: Paris Observatory, 2020. P. 243–247.
The decadal instabilities in Earth’s rotation (DIER) are thought to be caused bythe interactions between the Earth’s core and its mantle. This hypothesissuccessfully explains whythere is a close correlation between DIER and the variations in the rate of the westward drift of thegeomagnetic eccentric dipole, since it is successfully reproduced by modeling of the redistribution ...
Added: November 30, 2020