Results 261 to 270 of about 89,813 (296)

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
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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
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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
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Modeling and forecast of the polar motion excitation functions for short-term polar motion prediction

Journal of Geodesy, 2004
Short-term forecast of the polar motion is considered by introducing a prediction model for the excitation function that drives the polar motion dynamics. The excitation function model consists of a slowly varying trend, periodic modes with annual and several sub-annual frequencies (down to the 13.6-day fortnightly tidal period), and a transient decay ...
T.M. Chin, R.S. Gross, J.O. Dickey
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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
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Hydrological excitation of polar motion determined from CMIP6 climate models

2021
<p>Climate models provide important information to understand how the climate has changed in the past and how it can evolve in the future. Such models simulate in detail the physics, chemistry and biology of the atmosphere, oceans and land hydrosphere.
Jolanta Nastula, Justyna Śliwińska, Małgorzata Wińska   +2 more
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Hydrological excitation of polar motion

2008
First harmonics of the gravity field (C21 and S21), derived from the Gravity Recovery and Climate Experiment (GRACE), and processed at different institutes, are used to determine thehydrological equatorial excitation function of polar motion. For that purpose time-variable gravity field solutions are made tidal free and free from modelled non-tidal ...
Seoane, Lucia, Nastula, J., Bizouard, Christian, Gambis, Daniel   +3 more
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Regional contributions to the atmospheric excitation of rapid polar motions

Journal of Geophysical Research: Atmospheres, 1989
Daily fields of surface pressure produced by the National Meteorological Center during 1981–1985 are used to identify the sectors of the globe over which changes in atmospheric mass contribute most importantly to the excitation of intraseasonal variations in the Earth's polar axis.
David A. Salstein, Richard D. Rosen
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Regional Multi-Fluid-Based Geophysical Excitation of Polar Motion

2013
By analyzing geophysical fluids’ geographic distribution, we can isolate the regional provenance for some of the important signals in polar motion. An understanding of such will enable us to determine whether certain climate signals can have an impact on polar motion.
Jolanta Nastula, David A. Salstein, Richard Gross   +2 more
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Hydrological Excitations of Polar Motion from GRACE Gravity Field Solutions

2015
We use the latest time-variable Earth gravity field harmonics from the GRACE satellite mission (Release 5 – RL05) to determine seasonal and nonseasonal scales of polar motion excitation functions from global geophysical fluids, and particularly from the portion from land-based hydrology.
J. Nastula, D. A. Salstein, W. Popiński
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