open access

https://hdl.handle.net/2115/52821

Estimation of period and Q of the Chandler wobble

英語

Chandler wobble

1996-12

Oxford University Press

Geophysical Journal International

127(3)

693-702

The period P and Q-value of the Chandler wobble are two fundamental functional of the Earth's internal physical properties and global geodynamics. We revisit the problem of the estimation of P and Q, using 10.8 yr of modern polar motion as well as contemporary atmospheric angular momentum (AAM) data. We make full use of the knowledge that AAM is a major broad-band excitation source for the polar motion. We devise two optimization criteria under the assumption that, after removal of coherent seasonal and long-period signals, the non-AAM excitation is uncorrelated with the AAM. The procedures lead to optimal estimates for P and Q. Our best estimates, judging from comprehensive sets of Monte Carlo simulations, are P= 433.7 ± 1.8 (1σ) days, Q=49 with a la range of (35, 100). In the process we also obtain (as a by-product) an estimate of roughly 0.8 for a ‘mixing ratio’ of the inverted-barometer (IB) effect in the AAM pressure term, indicating that the ocean behaves nearly as IB in polar motion excitation on temporal scales from months to years

学術雑誌論文

Version of Record

This article has been accepted for publication in Geophysical Journal International ©:The Authors 1996 Published by Oxford University Press on behalf of The Royal Astronomical Society All rights reserved.

0956-540X