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Earth's rotation variations: a wavelet analysis
Author(s) -
Chao Benjamin F.,
Chung WeiYung,
Shih ZongRong,
Hsieh YiKai
Publication year - 2014
Publication title -
terra nova
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.353
H-Index - 89
eISSN - 1365-3121
pISSN - 0954-4879
DOI - 10.1111/ter.12094
Subject(s) - polar motion , earth's rotation , speed wobble , rotation (mathematics) , solid earth , geology , geodesy , oscillation (cell signaling) , wavelet , angular momentum , rotation period , geophysics , signal (programming language) , polar , earth (classical element) , periodic function , physics , geometry , classical mechanics , astrophysics , mathematics , astronomy , chemistry , computer science , biochemistry , stars , artificial intelligence , programming language , quantum mechanics
Historical to up‐to‐date data of the minute variations in the solid Earth's rotation are subjected to a comprehensive time‐frequency wavelet analysis. The length‐of‐day for the period 1962–2012 confirms the presence of a prominent, robust 6‐year periodicity and reveals an anomalously strong 18.6‐year tidal oscillation as well as a ~13‐year quasi‐periodic signal. The polar‐motion excitation for the period 1900–2012 validates the existence of the ~26‐year Markowitz wobble and shows an ~8‐year quasi‐periodic signal, but no appreciable 18.6‐year periodicity. Although it is known that exchanges of angular momentum with the geophysical fluids are responsible for the rotational variations of the solid Earth, the exact physical mechanisms involved on interannual‐to‐decadal timescales are still far from understood.