Results 261 to 270 of about 1,852,127 (286)

Oceanic excitation of polar motion: Identification of specific oceanic areas important for polar motion excitation

Journal of Geodynamics, 2012
Abstract In this paper regional values of the oceanic excitation function of polar motion are computed from bottom pressure and oceanic current fields from the ECCO/JPL data-assimilating model kf080 for the period 1993–2009. The influence of different geographic regions of the ocean on the excitation of polar motion is determined by calculating ...
Jolanta Nastula, David Salstein, Richard Gross   +2 more
exaly   +2 more sources

Excitation of non-atmospheric polar motion by the migration of the Pacific Warm Pool

Journal of Geodesy, 2004
Changes in the annual variation of the Earth's polar motion are found to be largely caused by the variation of the atmospheric angular momentum (AAM). Recent simulation results of oceanic general circulation models further suggest global oceanic effects ...
W T Liu, X L Ding
exaly   +2 more sources

Atmospheric excitation of nonseasonal polar motion

Journal of Geophysical Research: Solid Earth, 1993
Analysis of nonseasonal polar motion excitation and atmospheric mass equatorial angular momentum (EAM) over land for the period 1980–1989 reveals a clear pattern of high power and correlation during the northern hemisphere (NH) winter followed by low power and correlation during the NH summer.
John Kuehne, Stuart Johnson, Clark R. Wilson   +2 more
openaire   +1 more source

Climate Excitation of Polar Motion

2002
Recently, Gross (2000) demonstrated that the Chandler wobble may be excited by a combination of oceanic and atmospheric processes during 1985–1996 using observational records and a general ocean circulation model. Aoyama and Naito (2001) suggest that the atmospheric wind and pressure variations by themselves maintain a major part of the observed ...
E. W. Leuliette, J. M. Wahr
openaire   +1 more source

On the Excitation and Damping of the Polar Motion

Publications of the Astronomical Society of Japan, 1965
Abstract In the present paper, the excitation and damping of the polar motion are treated as a series of stochastic process, and the damping coefficient and constants concerning to the excitation of the polar motion are determined. The damping .coefficient thus determined is 0.320 (year–1), which is very close to that obtained by WALKER ...
openaire   +1 more source

Excitation of polar motion by earthquake displacement field

Chinese Astronomy and Astrophysics, 1982
Abstract We discuss the excitation of polar motion by earthquake displacement field. Instead of the usual static equilibrium equations in the literature, we use an improved set as given in /1/, which guarantee continuity at the core-mantle boundary. We take the parameter values of three earthquakes from /2/.
null Song Guo-xuan, null Zhao Ming, null Zheng Da-wei   +2 more
openaire   +1 more source

Polar motion excitation – A broad-band perspective

Journal of Geodynamics, 2012
Abstract Many recent studies of polar motion have demonstrated that climate-related variations (air and water motion and mass redistribution) provide the dominant source of polar motion excitation over virtually the entire band of frequencies that can be studied with modern space geodetic data.
Clark R. Wilson, Jianli Chen
openaire   +1 more source

Regional Atmospheric Angular Momentum Contributions to Polar Motion Excitation

Journal of Geophysical Research: Solid Earth, 1998
We focus on a regional analysis of equatorial components of the effective atmospheric angular momentum (EAAM) functions that measure the excitation of polar motion. These functions are computed from National Centers for Environmental Prediction and National Center for Atmospheric Research (NCEP/NCAR) reanalysis data both globally and in 108 geographic ...
Jolanta Nastula, David Salstein
openaire   +1 more source

On Some Properties of the Excitation and Damping of the Polar Motion

Publications of the Astronomical Society of Japan, 1972
Abstract Values of the Chandlerian period and the damping coefficient of the polar motion are calculated for ten year intervals from 1900.0 to 1970.0, using a method developed by Sekiguchi (1966). The damping coefficient varies between 0.074 and 0.008 year−1 through this period, and is correlative with the variation of the Chandlerian ...
openaire   +1 more source

Air and Water Contributions to Polar Motion Excitation

1990
Modern space-geodetic observations show that the Earth’s polar motion occurs over a broad range of frequencies from below the Chandler frequency at fractions of a cycle per year (cpy), up to tens of cycles per year. Across this entire frequency band, the excitation sources for polar motion are only partially understood.
Clark R. Wilson, John Kuehne
openaire   +1 more source