2024-03-29T10:41:10Zhttps://eprints.lib.hokudai.ac.jp/dspace-oai/requestoai:eprints.lib.hokudai.ac.jp:2115/528212022-11-17T02:08:08Zhdl_2115_20039hdl_2115_116Estimation of period and Q of the Chandler wobble1000060313045Furuya, MasatoChao, B. F.open accessThis 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.atmospheric angular momentumChandler wobble450The 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 yearsOxford University Press1996-12engjournal articleVoRhttp://hdl.handle.net/2115/52821https://doi.org/10.1111/j.1365-246X.1996.tb04047.x0956-540XGeophysical Journal International1273693702https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/52821/1/j.1365-246X.1996.tb04047.x.pdfapplication/pdf1.42 MB1996-12