Atmospheric quasi-14 month fluctuation and excitation of the Chandler wobble

Aoyama, Yuichi; Naito, Isao; Iwabuchi, Tetsuya; Yamazaki, Nobuo

doi:10.1186/bf03352480

Cited by 13 publications

(18 citation statements)

References 23 publications

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“…The theoretical period is consistent with other estimates of the observed Chandler period based on analyses of polar motion time series (e.g., Vicente & Wilson 1997). However, there is no consensus on the value of Q: depending on the time interval and the analysis method, it ranges from 50 (Furuya & Chao 1996;Kuehne et al 1996) to 180 (Vicente & Wilson 1997;Aoyama et al 2003). Gross (2000) and Brzeziński & Nastula (2002) find intermediate values of ∼140.…”

Section: The Polar Motion Excitation By Fluid Layerssupporting

confidence: 71%

“…According to Celaya et al (1999), Gross (2000), and Brzeziński & Nastula (2002), the CW excitation is accounted for, on average, by the atmosphere and oceans. Following Aoyama et al (2003), atmospheric and ocean-bottom pressure and winds are comparable sources of excitation, intermittently playing a prominent role. Seitz & Schmidt (2005) conclude that the atmospheric and oceanic bottom pressure fluctuations are the prominent cause of the CW variability.…”

Section: Introductionmentioning

confidence: 99%

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The Earth’s variable Chandler wobble

Bizouard

Remus

Lambert

et al. 2011

A&A

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Aims. We investigated the causes of the Earth's Chandler wobble variability over the past 60 years. Our approach is based on integrating of the atmospheric and oceanic angular momentum computed by global circulation models. We directly compared the result of the integration with the Earth's pole coordinate observed by precise astrometric, space, and geodetic techniques. This approach differs from the traditional approach in which the observed polar motion is transformed into a so-called geodetic excitation function, and compared afterwards with the angular momentum of the external geophysical fluid layers. Methods. In the time domain, we integrated the atmospheric angular momentum time series from the National Center for Environmental Prediction/National Center for Atmospheric Research Reanalysis project and the oceanic angular momentum data from the ECCO consortium. We extracted the Chandler wobble from this modeled polar motion by singular spectrum analysis, and compared it with the Chandler wobble extracted from the observed polar motion given by the International Earth Rotation and Reference Systems Service data. Results. We showed that the combination of the atmosphere and the oceans explains most of the observed Chandler wobble variations, and is consistent with results reported in the literature and obtained with the traditional approach. Our approach allows one to appreciate the separate contributions of the atmosphere and the oceans to the various bumps and valleys observed in the Chandler wobble. Though the atmosphere explains the Chandler wobble amplitude variations between 1949 and 1970, the reexcitation of the Chandler wobble that begins in the 1980s, after a minimum around 1970, and that reaches its maximum in the late 1990s is due to the oceans, while the atmospheric contribution remains stable within the same period.

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Section: The Polar Motion Excitation By Fluid Layerssupporting

confidence: 71%

Section: Introductionmentioning

confidence: 99%

The Earth’s variable Chandler wobble

Bizouard

Remus

Lambert

et al. 2011

A&A

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“…Moreover, there is statistical evidence that the Chandler wobble is predominantly a deterministic process. [25,26,27] Some authors have therefore concluded that the wobble is forced by geophysical fluid circulations [11,12,13,14]. In that case the estimates of Q w obtained by Jeffreys's method do not apply directly (a point stressed in [21], but ignored by some authors).…”

Section: Dissipation and Maintenancementioning

confidence: 99%

“…Proposed solutions to this puzzle have, for the most part, relied either on stochastic perturbations to the Earth's mass distribution [9,10], or on marine and atmospheric circulations that might force the wobble near its resonant ω Ch . [11,12,13,14] Here we propose a new model of the Chandler wobble as a weakly non-linear self-oscillation. Unlike a resonator, a self-oscillator maintains periodic motion at the expense of a power source with no corresponding periodicity [15,16].…”

Section: Introductionmentioning

confidence: 99%

Chandler Wobble: Stochastic and Deterministic Dynamics

Jenkins

2016

Dynamical Systems: Theoretical and Experimental Analysis

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We propose a model of the Earth's torqueless precession, the "Chandler wobble", as a self-oscillation driven by positive feedback between the wobble and the centrifugal deformation of the portion of the Earth's mass contained in circulating fluids. The wobble may thus run like a heat engine, extracting energy from heat-powered geophysical circulations whose natural periods would otherwise be unrelated to the wobble's observed period of about fourteen months. This can explain, more plausibly than previous models based on stochastic perturbations or forced resonance, how the wobble is maintained against viscous dissipation. The self-oscillation is a deterministic process, but stochastic variations in the magnitude and distribution of the circulations may turn off the positive feedback (a Hopf bifurcation), accounting for the occasional extinctions, followed by random phase jumps, seen in the data. This model may have implications for broader questions about the relation between stochastic and deterministic dynamics in complex systems, and the statistical analysis thereof.

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“…Recently, air pressure [Plag, 1997],tropospheric winds [Aoyama and Naito, 2001 ], and ocean-bottom pressure variations [Gross, 2000] have been independently proposed as major contribu tions to the excitation of the Chandler wobble. A 14-to 16-month oscillation (FSO) in the atmosphere-ocean system has also been pro posed as a candidate mechanism that could force a wobble having a frequency close to that of the Chandler resonance [Plag, 1997;Aoyama et al, 2003].…”

Section: Section Newsmentioning

confidence: 99%

Forcing of polar motion in the Chandler frequency band: An opportunity to evaluate interannual climate variations

et al. 2005

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The Earth rotates about its axis once per day but does not do so uniformly. The length of the day changes by as much as a millisecond from day to day and the Earth wobbles as it rotates. That the Earth should wobble was predicted by the Swiss mathematician Leonhard Euler in 1765, but it was not until 1891 that the wobbling motion of the Earth was detected by the American astronomer Seth Carlo Chandler, Jr. In fact, Chandler observed that the Earth has two distinct wobbles, one with an annual period and the other with a 14‐month period. The annual wobble is a forced motion of the Earth caused by seasonal variations in the atmosphere, oceans, and hydrosphere.

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Atmospheric quasi-14 month fluctuation and excitation of the Chandler wobble

Cited by 13 publications

References 23 publications

The Earth’s variable Chandler wobble

The Earth’s variable Chandler wobble

Chandler Wobble: Stochastic and Deterministic Dynamics

Forcing of polar motion in the Chandler frequency band: An opportunity to evaluate interannual climate variations

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