Excitation of the Earth’s Orientation by Geophysical fluids and Geomagnetic Jerks

Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985815%3A_____%2F20%3A00539408" target="_blank" >RIV/67985815:_____/20:00539408 - isvavai.cz</a>
Result on the web
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DOI - Digital Object Identifier
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Result language
angličtina
Original language name
Excitation of the Earth’s Orientation by Geophysical fluids and Geomagnetic Jerks
Original language description
It is well known that the Earth’s orientation is affected, in addition to external torques caused by the Moon, Sun and planets, also by excitation by geophysical fluids (atmosphere, oceans, and hydrology). Only very recently it was noticed that the observed changes of the amplitud and phase of the free modes (Chandler wobble, Free Core Nutation) are correlated with the rapid changes of the second time derivative of geomagnetic field, so called geomagnetic jerks (GMJ). These events occur irregularly, in intervals of several years, and last typically several months. We use Brzezinski’s broad band Liouville equations (expressed both in terrestrial and celestial reference frames) to integrate numerically the changes of Earth’s orientation due to geophysical excitations. We use standard excitations by atmosphere and oceans (hydrology being neglected), and we also add GMJ effect, modeled as impulse-like functions centered at GMJ epochs. We are able to demonstrate that the agreement of the integrated Earth orientation with the observed values significantly improves when GMJ effect is considered. This approach enables us also to determine the parameters of the free modes (period, Q-factor) with improved accuracy.
Czech name
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Czech description
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Project
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Continuities
I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year
2020
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Article name in the collection
Proceedings of the Journées 2017: Futhering our knowledge of Earth rotation
ISBN
978-84-1302-092-1
ISSN
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e-ISSN
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Number of pages
7
Pages from-to
3-10
Publisher name
Observatoire de Paris
Place of publication
Paris
Event location
Alicante
Event date
Sep 25, 2017
Type of event by nationality
WRD - Celosvětová akce
UT code for WoS article
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