Geomagnetic excitation of nutation

0452112 - ASÚ 2016 RIV RU eng C - Konferenční příspěvek (zahraniční konf.)
Ron, Cyril - Vondrák, Jan
Geomagnetic excitation of nutation.
Journées 2014 systemes de référénce spatio-temporels. St. Petersburg: Pulkovo Observatoy, 2015 - (Malkin, Z.; Capitaine, N.), s. 191-194. ISBN 978-5-9651-0873-2.
[Journées 2014 systemes de référénce spatio-temporels. St. Petersburg (RU), 20.9..22.0-20.9..24.0]
Grant CEP: GA ČR GA13-15943S
Institucionální podpora: RVO:67985815
Klíčová slova: astrometry * Earth rotation * reference systems
Kód oboru RIV: BN - Astronomie a nebeská mechanika, astrofyzika
http://syrte.obspm.fr/jsr/journees2014/pdf/Ron.pdf

We tested the hypothesis of Malkin (2013), who demonstrated that the observed changes of Free Core Nutation parameters (phase, amplitude) occur near the epochs of geomagnetic jerks. We found that if the numerical integration of Brzeziński broad-band Liouville equations of atmospheric/oceanic excitations is re-initialized at the epochs of geomagnetic jerks, the agreement between the integrated and observed celestial pole offsets is improved (Vondrák & Ron, 2014). Nevertheless, this approach assumes that the influence of geomagnetic jerks leads to a stepwise change in the position of celestial pole, which is physically not acceptable. Therefore we introduce a simple continuous excitation function that hypothetically describes the influence of geomagnetic jerks, and leads to rapid but continuous changes of pole position. The results of numerical integration of atmospheric/oceanic excitations and this newly introduced excitation are then compared with the observed celestial pole offsets, and prove that the agreement is improved significantly.
Trvalý link: http://hdl.handle.net/11104/0253138