How large is the retrograde annual wobble?

1991 ◽  
Vol 18 (9) ◽  
pp. 1735-1738 ◽  
Author(s):  
N. E. King ◽  
Duncan Carr Agnew
Keyword(s):  
Annual Wobble

scholarly journals A note on the annual wobble excitation due to the seasonal atmospheric loading on continents

2018 ◽  
Vol 29 (6) ◽  
pp. 721-729
Author(s):  
Sung-Ho Na ◽  
Jungho Cho ◽  
Ki-Weon Seo ◽  
Kook-Hyoun Youm ◽  
Wenbin Shen
Keyword(s):  
Atmospheric Loading ◽  
Annual Wobble

scholarly journals Is Chandler frequency constant?

1988 ◽  
Vol 128 ◽  
pp. 359-364 ◽  
Author(s):  
Jan Vondrák
Keyword(s):  
Polar Motion ◽  
Phase Changes ◽  
Negative Phase ◽  
Chandler Wobble ◽  
Probable Explanation ◽  
Equilibrium Response ◽  
Rapid Changes ◽  
Chandler Frequency ◽  
Most Probable Explanation ◽  
Annual Wobble

The observed polar motion in the period 1860–1985 is analyzed in order to decide whether Chandler frequency was constant. It is shown that while the phase of annual wobble was very stable throughout the interval in question, Chandler wobble phase was subject to sometimes very rapid changes. The most pronounced negative phase changes were always accompanied by extremely low amplitudes, and a significant correlation was found between Chandler wobble phase and its integrated amplitude. The most probable explanation is that the frequency of Chandler wobble is variable and amplitude-dependent, which might be caused by non-equilibrium response of the ocean.

The status of Chandler wobble

2020 ◽  
Author(s):  
Guocheng Wang ◽  
Lintao Liu ◽  
Jinzhao Liu ◽  
Yi Tu
Keyword(s):  
Edge Effect ◽  
Polar Motion ◽  
Chandler Wobble ◽  
Basis Pursuit ◽  
Fourier Basis ◽  
The Earth ◽  
The Status ◽  
Band Pass ◽  
Main Components ◽  
Annual Wobble

<p>The Chandler wobble (CW) and Annual wobble (AW) are the main components of the Earth’s Polar motion, which play an important role in our understanding of their excitations. The Fourier Basis Pursuit Band-Pass Filtering (FBPBPF) method, which can effectively suppress the edge effect, are applied to extract the CW and AW in Earth's polar motion during 1900-2016. Through analyze the variation of CW extracted by the FBPBPF method, we find that the amplitude of the CW has been diminishing since 1995. However, the amplitude of the CW had stopped decline in the last year, and start to increase at now.</p>

scholarly journals Analysis of Long Time Series of Polar Motion

2000 ◽  
Vol 178 ◽  
pp. 321-332
Author(s):  
H. Schuh ◽  
B. Richter ◽  
S. Nagel
Keyword(s):  
Time Series ◽  
Polar Motion ◽  
Weighting Function ◽  
Chandler Wobble ◽  
Linear Drift ◽  
Long Time Series ◽  
Least Squares Fit ◽  
Long Time ◽  
Decadal Variations ◽  
Annual Wobble

AbstractTwo long time series of polar motion were analysed with respect to a linear drift, decadal variations, Chandler wobble and annual wobble: the C01 series published by the International Earth Rotation Service (IERS) and the pole series which J. Vondrák, obtained by re-analysis of the classical astronomical observations using the HIPPARCOS reference frame (1899.7–1992.0). By a least-squares fit the linear drift of the pole, usually called ‘secular polar motion,’ was determined to 3.31 milliarcseconds/year (mas/yr) toward 76.1° West longitude. For this fit the a priori correlations within each pair of pole coordinates were taken into account, and the weighting function was calculated by estimation of empirical variance components. The decadal variations of the pole path were determined by Fourier analysis. Using a sliding window analysis, the variability of the periods, the amplitudes and the phases of the Chandler wobble and annual wobble was investigated. The variances of the results and the number of iterations needed to get a convergence in the nonlinear approach show that the new time series by Vondrák is more homogeneous and consistent than the IERS C01 series.

scholarly journals Estimate of wind stressed sea level excitation of the Earth's annual wobble

1980 ◽  
Vol 60 (2) ◽  
pp. 187-207 ◽  
Author(s):  
W. P. O'Connor
Keyword(s):  
Sea Level ◽  
Annual Wobble

scholarly journals Snow-load excitation of the Earth's annual wobble

1988 ◽  
Vol 128 ◽  
pp. 373-380 ◽  
Author(s):  
B. Fong Chao ◽  
William P. O'Connor ◽  
Alfred T. C. Chang
Keyword(s):  
Rotation Axis ◽  
Microwave Remote Sensing ◽  
Seasonal Cycles ◽  
Data Set ◽  
Snow Load ◽  
Depth Data ◽  
Motion Measurements ◽  
Remote Sensing Techniques ◽  
Annual Wobble ◽  
Future Plans

A global, monthly snow depth data set has been generated from weather satellite (Nimbus 7) observations using passive microwave remote-sensing techniques. In this paper we analyzed five years of data, 1980–1984, to compute the snow-load excitation of the annual wobble of the Earth's rotation axis. A uniform sea-level decrease has been assumed in order to conserve water mass. The result shows dominant seasonal cycles. The prograde component of the annual excitation is Ψ+ = (5.0 milliarcsec, −110*) and the retrograde component Ψ− = (5.0 milliarcsec, −31*). These computed values are compared with previous groundwater estimates, as well as the inferred values from ILS and LAGEOS polar motion measurements. The importance of accurate data is stressed and future plans proposed.

scholarly journals Analysis of 25 Years of Polar Motion Derived from the DORIS Space Geodetic Technique Using FFT and SSA Methods

Sensors ◽  
2020 ◽  
Vol 20 (10) ◽  
pp. 2823
Author(s):  
Qiaoli Kong ◽  
Linggang Zhang ◽  
Litao Han ◽  
Jinyun Guo ◽  
Dezhi Zhang ◽  
...  
Keyword(s):  
Time Series ◽  
Spectrum Analysis ◽  
Polar Motion ◽  
Singular Spectrum Analysis ◽  
Close Relation ◽  
Good Method ◽  
Chandler Wobble ◽  
Fast Transform ◽  
Space Geodetic Techniques ◽  
Annual Wobble

Polar motion (PM) has a close relation to the Earth’s structure and composition, seasonal changes of the atmosphere and oceans, storage of waters, etc. As one of the four major space geodetic techniques, doppler orbitography and radiopositioning integrated by satellite (DORIS) is a mature technique that can monitor PM through precise ground station positioning. There are few articles that have analyzed the PM series derived by the DORIS solution in detail. The aim of this research was to assess the PM time-series based on the DORIS solution, to better capture the time-series. In this paper, Fourier fast transform (FFT) and singular spectrum analysis (SSA) were applied to analyze the 25 years of PM time-series solved by DORIS observation from January 1993 to January 2018, then accurately separate the trend terms and periodic signals, and finally precisely reconstruct the main components. To evaluate the PM time-series derived from DORIS, they were compared with those obtained from EOP 14 C04 (IAU2000). The results showed that the RMSs of the differences in PM between them were 1.594 mas and 1.465 mas in the X and Y directions, respectively. Spectrum analysis using FFT showed that the period of annual wobble was 0.998 years and that of the Chandler wobble was 1.181 years. During the SSA process, after singular value decomposition (SVD), the time-series was reconstructed using the eigenvalues and corresponding eigenvectors, and the results indicated that the trend term, annual wobble, and Chandler wobble components were accurately decomposed and reconstructed, and the component reconstruction results had a precision of 3.858 and 2.387 mas in the X and Y directions, respectively. In addition, the tests also gave reasonable explanations of the phenomena of peaks of differences between the PM parameters derived from DORIS and EOP 14 C04, trend terms, the Chandler wobble, and other signals detected by the SSA and FFT. This research will help the assessment and explanation of PM time-series and will offer a good method for the prediction of pole shifts.

How to Detect the Chandler and the Annual Wobble of the Earth with a Large Ring Laser Gyroscope

2011 ◽  
Vol 107 (17) ◽  
Author(s):  
K. U. Schreiber ◽  
T. Klügel ◽  
J.-P. R. Wells ◽  
R. B. Hurst ◽  
A. Gebauer
Keyword(s):  
Ring Laser ◽  
Large Ring ◽  
The Earth ◽  
Ring Laser Gyroscope ◽  
Laser Gyroscope ◽  
Annual Wobble
Sign in / Sign up

Export Citation Format

Share Document