Period and Q-Factor of Free Core Nutation, Based on Different Geophysical Excitations and VLBI Solutions

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985815%3A_____%2F20%3A00537141" target="_blank" >RIV/67985815:_____/20:00537141 - isvavai.cz</a>

Result on the web

<a href="http://hdl.handle.net/11104/0314892" target="_blank" >http://hdl.handle.net/11104/0314892</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.13168/AGG.2020.0015" target="_blank" >10.13168/AGG.2020.0015</a>

Result language

angličtina

Original language name

Period and Q-Factor of Free Core Nutation, Based on Different Geophysical Excitations and VLBI Solutions

Original language description

Three variants of geophysical excitations and seven different VLBI solutions of celestial pole offsets (CPO) are used to determine period and Q-factor of Free Core Nutation (FCN). Brzezinski's broad-band Liouville equations (Brzezinski, 1994) are numerically integrated to derive geophysical effects in nutation in time domain. Possible effect of geomagnetic jerks (GMJ) is also considered. Best-fitting values of FCN parameters are estimated by least-squares fit to observed CPO, corrected for the differences between the FCN parameters used in IAU 2000 model of nutation and newly estimated ones, MHB transfer function is used to compute these corrections. It is demonstrated that different VLBI solutions lead to FCN parameters that agree on the level of their formal uncertainties, but different models of geophysical excitations change the results more significantly. Using GMJ excitations always brings improvement of the fit between integrated and observed CPO. The obtained results show that the best fit is achieved when only GMJ excitations are used. Our conclusion is that GMJ are very probably more important for exciting FCN than the atmosphere and oceans. Empirical Sun-synchronous correction, introduced in the present IAU 2000 nutation model, cannot be explained by diurnal atmospheric tidal effects.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

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OECD FORD branch

10308 - Astronomy (including astrophysics,space science)

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

Name of the periodical

Acta Geodynamica et Geomaterialia

ISSN

2336-4351

e-ISSN

—

Volume of the periodical

17

Issue of the periodical within the volume

2

Country of publishing house

CZ - CZECH REPUBLIC

Number of pages

9

Pages from-to

207-215

UT code for WoS article

000546750100006

EID of the result in the Scopus database

2-s2.0-85090734595