Open AccessEstimation of period and Q of the Chandler wobble
Author(s) -
Furuya M.,
Chao B. F.
Publication year - 1996
Publication title -
geophysical journal international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0956-540X
DOI - 10.1111/j.1365-246x.1996.tb04047.x
Subject(s) - polar motion , earth's rotation , excitation , geodesy , angular momentum , polar , speed wobble , geodynamics , rotation (mathematics) , secular variation , range (aeronautics) , physics , geology , mathematics , statistical physics , geophysics , geometry , classical mechanics , quantum mechanics , tectonics , seismology , materials science , composite material
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