Chandler wobble


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Chandler wobble

(chand -ler) A small continuous variation in the location of the geographic poles on the Earth's surface. It leads to a variation of latitude of points on the Earth because latitude is measured from the equator midway between the poles. It does not affect the celestial coordinates of a body. The variation in polar location is resolved into two almost circular components, one (diameter: 6 meters; period: 12 months) resulting from seasonal changes in ice, snow, and atmospheric mass distribution; the second (diameter: 3–15 meters; period: 428 days) is believed to arise from movements of material within the Earth.

Chandler wobble

[′chand·lər ‚wäb·əl]
(geophysics)
A movement in the earth's axis of rotation, the period of motion being about 14 months. Also known as Eulerian nutation.
References in periodicals archive ?
This allows us to investigate the Earth's rheology (deformational behaviour in response to forces) at time scales intermediate between the frequencies of seismic vibrations following earthquakes (seconds to minutes) and the Chandler wobble (an almost-regular rotational movement at near-yearly timescales).
(2002), who found that the rapid changes in the Chandler wobble phase follow the GMJ with a delay of 1-3 years.
The wobble in Earth's axis of rotation is a combination of two major components: Chandler wobble, thought to arise as Earth is not rigid, and another is the annual wobble, related to Earth's orbit around the sun.
* Motion of the oceans, that cause the additional forcing of polar motion (namely the excitation of the free Chandler wobble), diurnal and sub-diurnal polar motion, and variations of the speed of rotation;
* Mystery solved: Long-term fluctuations in pressure at the ocean's bottom appear to drive the Chandler wobble, which causes the North Pole to wander a path of about 20 feet every 14 months (158: 111).
According to Goss's calculations, based on IERS data, two-thirds of the Chandler wobble is caused by such changes.
Earth is no exception to this general rule, although it does exhibit several tottering motions, the two most prominent being the so-called Chandler wobble and the precession of the equinoxes.
These elements combine in an effect known as the Chandler wobble to create polar motion.
Here [e.sub.R] denotes the dynamical ellipticity of the rigid Earth used to compute the rigid solution, [N.sub.0], [Q.sub.j] are complex "strength" parameters, and [s.sub.j] are four complex resonance frequencies corresponding to Chandler Wobble (CW, with terrestrial period of about 435 days), retrograde FCN (with celestial period of about 430 days), Prograde Free Core Nutation (PFCN, with celestial period of about 1020 days) and Inner Core Wobble (ICW, with terrestrial period of about 2400 days), respectively.
By itself, the Chandler wobble 0would cause the pole to move back and forth about 20 feet every 14 months.
Here [e.sub.R] denotes the dynamical ellipticity of the rigid Earth used to compute the rigid solution, [N.sub.0], [Q.sub.j] are complex constants, and [s.sub.j] are four complex resonance frequencies corresponding to Chandler Wobble (CW, with terrestrial period of about 435 days), RFCN, with celestial period of about 430 days, Prograde Free Core Nutation (PFCN, with celestial period of about 1020 days) and Inner Core Wobble (ICW, with terrestrial period of about 2400 days) respectively.
Because of a puzzling phenomenon called the Chandler wobble, they will probably sit about 10 meters apart.