Centre de documentation
scientifique

Free decay and excitation of the chandler wobble: self-consistent estimates of the period and quality factor / Wei Chen in Journal of geodesy, vol 97 n° 4 (April 2023)  

Public [article]  inJournal of geodesy > vol 97 n° 4 (April 2023) . - n° 36 Titre : Free decay and excitation of the chandler wobble: self-consistent estimates of the period and quality factor Type de document : Article/Communication Auteurs : Wei Chen, Auteur ; Yifei Chen, Auteur ; et al., Auteur Année de publication : 2023 Article en page(s) : n° 36 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] mouvement du pôle [Termes IGN] terme de Chandler Résumé : (auteur) The period TCW and quality factor QCW of the Chandler wobble (CW) as well as polar motion (PM) transfer functions are all determined by the Earth’s layered structure, mass distribution, elasticity, rheology and energy dissipation, via the Earth’s dynamic figure parameters and complex degree-2 Love numbers. However, most previous studies used geophysical excitations derived from real-valued PM transfer functions to invert for TCW and QCW, thus leading to results that are not self-consistent. By separating the observed PM into the freely decaying CW and the excited PM, a traverse-based method is proposed to search values of TCW and QCW that can fit both sides simultaneously, yielding the self-consistent estimates of TCW = 430.4 mean solar days and QCW = 130. This implies the degree-2 tidal Love number k = 0.35011 − 0.00226i and load Love number k' =  − 0.36090 + 0.00233i, and the PM transfer functions TNL = 1.80001 − 0.00692i (non-loading) and TL = 1.15040 − 0.00023i (loading) valid at the Chandler period. Numéro de notice : A2023-176 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1007/s00190-023-01727-z Date de publication en ligne : 10/04/2023 En ligne : https://doi.org/10.1007/s00190-023-01727-z Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=103287 [article]

Multivariate analysis of GPS position time series of JPL second reprocessing campaign / Ali Reza Amiri-Simkooei in Journal of geodesy, vol 91 n° 6 (June 2017)  

Public [article]  inJournal of geodesy > vol 91 n° 6 (June 2017) . - pp 685 - 704 Titre : Multivariate analysis of GPS position time series of JPL second reprocessing campaign Type de document : Article/Communication Auteurs : Ali Reza Amiri-Simkooei, Auteur ; T.H. Mohammadloo, Auteur ; Donald F. Argus, Auteur Année de publication : 2017 Article en page(s) : pp 685 - 704 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] analyse multivariée [Termes IGN] bruit blanc [Termes IGN] bruit rose [Termes IGN] campagne GPS [Termes IGN] centre de phase [Termes IGN] coordonnées GPS [Termes IGN] série temporelle [Termes IGN] terme de Chandler [Vedettes matières IGN] Traitement de données GNSS Résumé : (Auteur) The second reprocessing of all GPS data gathered by the Analysis Centers of IGS was conducted in late 2013 using the latest models and methodologies. Improved models of antenna phase center variations and solar radiation pressure in JPL’s reanalysis are expected to significantly reduce errors. In an earlier work, JPL estimates of position time series, termed first reprocessing campaign, were examined in terms of their spatial and temporal correlation, power spectra, and draconitic signal. Similar analyses are applied to GPS time series at 89 and 66 sites of the second reanalysis with the time span of 7 and 21 years, respectively, to study possible improvements. Our results indicate that the spatial correlations are reduced on average by a factor of 1.25. While the white and flicker noise amplitudes for all components are reduced by 29–56 %, the random walk amplitude is enlarged. The white, flicker, and random walk noise amount to rate errors of, respectively, 0.01, 0.12, and 0.09 mm/yr in the horizontal and 0.04, 0.41 and 0.3 mm/yr in the vertical. Signals reported previously, such as those with periods of 13.63, 14.76, 5.5, and 351.4 / n for n=1,2,…,8 days, are identified in multivariate spectra of both data sets. The oscillation of the draconitic signal is reduced by factors of 1.87, 1.87, and 1.68 in the east, north and up components, respectively. Two other signals with Chandlerian period and a period of 380 days can also be detected. Numéro de notice : A2017-297 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-016-0991-9 En ligne : http://dx.doi.org/10.1007/s00190-016-0991-9 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=85328 [article]

Ultra short-term prediction of pole coordinates via combination of empirical mode decomposition and neural networks / Yu Lei in Artificial satellites, vol 51 n° 4 (December 2016)  

Public [article]  inArtificial satellites > vol 51 n° 4 (December 2016) . - pp 149 – 161 Titre : Ultra short-term prediction of pole coordinates via combination of empirical mode decomposition and neural networks Type de document : Article/Communication Auteurs : Yu Lei, Auteur ; Danning Zhao, Auteur ; Hongbing Cai, Auteur Année de publication : 2016 Article en page(s) : pp 149 – 161 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] filtre passe-bas [Termes IGN] fonction de base radiale [Termes IGN] mouvement du pôle [Termes IGN] oscillation [Termes IGN] prévision à court terme [Termes IGN] réseau neuronal artificiel [Termes IGN] terme de Chandler Résumé : (auteur) It was shown in the previous study that the increase of pole coordinates prediction error for about 100 days in the future is mostly caused by irregular short period oscillations. In this paper, the ultra short-term prediction of pole coordinates is studied for 10 days in the future by means of combination of empirical mode decomposition (EMD) and neural networks (NN), denoted EMD-NN. In the algorithm, EMD is employed as a low pass filter for eliminating high frequency signals from observed pole coordinates data. Then the annual and Chandler wobbles are removed a priori from pole coordinates data with high frequency signals eliminated. Finally, the radial basis function (RBF) networks are used to model and predict the residuals. The prediction performance of the EMD-NN approach is compared with that of the NN-only solution and the prediction methods and techniques involved in the Earth orientation parameters prediction comparison campaign (EOP PCC). The results show that the prediction accuracy of the EMD-NN algorithm is better than that of the NN-only solution and is also comparable with that of the other existing prediction method and techniques. Numéro de notice : A2016-977 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1515/arsa-2016-0013 En ligne : https://doi.org/10.1515/arsa-2016-0013 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=83688 [article]

Physically consistent system model for the study of the Earth's rotation, surface deformation and gravity field parameters / A. Hense (2009)

Public Titre : Physically consistent system model for the study of the Earth's rotation, surface deformation and gravity field parameters : scientific results of the DFG project Type de document : Monographie Auteurs : A. Hense, Auteur ; J. Sündermann, Auteur ; Hermann Drewes, Auteur ; et al., Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 2009 Collection : DGK - B Sous-collection : Angewandte Geodäsie num. 317 Importance : 53 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-8596-1 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] champ de pesanteur terrestre [Termes IGN] circulation atmosphérique [Termes IGN] circulation océanique [Termes IGN] déformation de la croute terrestre [Termes IGN] modèle hydrographique [Termes IGN] modèle physique [Termes IGN] pesanteur terrestre [Termes IGN] rotation de la Terre [Termes IGN] surcharge océanique [Termes IGN] terme de Chandler Index. décimale : 30.40 Géodésie physique Résumé : (Auteur) [introduction] This report is the final report of a serie of projects which studied the Earth's rotational parameters angular momentum, tensor of inertia as well as related variables of the Earth's gravitational field. A system view has been taken by trying to incorporate the contributions from the various subsystems of the Earth system in a physically consistent way. This introduction will highlight the project history and performance since 1996 and the state of the art in 2000. Note de contenu : 1. Introduction 1.1 The projects 1.2 Historical overview and motivations 2. Models of subsystems 2.1 Atmosphere models ECHAM 2.1.1 ECHAM5 2.1.2 Stand-alone atmosphere 20th century simulation 2.1.3 Results 2.2 Ocean model OMCT 2.3 Hydrological Discharge Model HDM 2.3.1 Continental hydrology modelling 2.3.1.1 SLS model component 2.3.1.2 HDM model component 2.3.1.3 Atmospheric forcing data 2.3.2 Results 2.3.2.1 Implementation of a 3-D relief model 2.3.2.2 Calculation of gravity field coefficients 2.3.2.3 Test simulations and validation of continental discharge with ECHAM4 and NCEP 2.3.2.4 Verification of simulated continental runoff (control runs) 2.3.2.5 Interface adaptation and verification of mass conservation at the boundaries in the coupled model system 2.3.2.6 Validation and analysis of continental water mass transports of ECOCTH 2.3.2.7 Statistical analysis and validation of simulated gravity field variations 2.3.2.8 Global water balance 2.3.3 Summary 3. Models of the coupled system 3.1 Coupled atmosphere-hydrosphere model ECOCTH 3.1.1 Model description 3.1.2 Validation 3.1.2.1 The lunisolar ocean tides 3.1.2.2 Global ocean circulation 3.1.2.3 Tropical variability and global warming 3.1.3 Results 3.1.3.1 Inter-annual variations and secular trends in length of day 3.2 Dynamic model of Earth rotation, gravity and surface deformation DyMEG 3.2.1 Numerical solution of the Liouville differential equation 3.2.2 Inverse model for surface deformations of the solid Earth due to mass loads 4. Results for Earth rotation, surface deformation and gravity 4.1 Validation of DyMEG with NCEP and ECCO 4.2 Results of DyMEG with ECOCTH forcing 5. Scientific highlights 5.1 Tidal mixing 5.1.1 Tidal mixing in OMCT2 5.1.2 Effect of tidal mixing on ocean water mass properties 5.2 Secular and decadal variations 5.2.1 Coupled simulation of Earth Rotation Parameters 5.2.2 Axial AAM long-term trends in 21st century scenario runs 5.3 Forcing mechanisms of the Chandler oscillation 5.3.1 Atmospheric and hydrospheric excitation of the Chandler oscillation 5.3.2 Noise as excitation mechanism of the Chandler oscillation 6. Conclusions and outlook 7. References Numéro de notice : 15454 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Monographie Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=62723

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
15454-01	30.40	Livre	Centre de documentation	Géodésie	Disponible

Polar motion modeling, analysis, and prediction with time dependent harmonic coefficients / Huseyin Baki Iz in Journal of geodesy, vol 82 n° 12 (December 2008)  

Public [article]  inJournal of geodesy > vol 82 n° 12 (December 2008) . - pp 871 - 881 Titre : Polar motion modeling, analysis, and prediction with time dependent harmonic coefficients Type de document : Article/Communication Auteurs : Huseyin Baki Iz, Auteur Année de publication : 2008 Article en page(s) : pp 871 - 881 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] modèle de simulation [Termes IGN] mouvement du pôle [Termes IGN] série temporelle [Termes IGN] terme de Chandler Résumé : (Auteur) A time dependent amplitude model was proposed for the analysis and prediction of polar motion time series. The formulation was implemented to analyze part of the new combined solution, EOP (IERS) C 04, daily polar motion time series of 14 years length using a statistical model with first order autoregressive disturbances. A new solution approach, where the serial correlations of the disturbances are eliminated by sequentially differencing the measurements, was used to estimate the model parameters using weighted least squares. The new model parsimoniously represents the 14-year time series with 0.5 mas rms fit, close to the reported 0.1 mas observed pole position precisions for the x and y components. The model can also predict 6 months into the future with less than 4 mas rms prediction error for both polar motion components, and down to sub mas for one-step ahead prediction as validated using a set of daily time series data that are not used in the estimation. Copyright Springer Numéro de notice : A2008-471 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-008-0215-z En ligne : https://doi.org/10.1007/s00190-008-0215-z Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29540 [article]

Exemplaires(2)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
266-08111	RAB	Revue	Centre de documentation	En réserve L003	Disponible
266-08112	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Résolution numérique des équations des déformations de la Terre / Paul Rebischung (2005)

Permalink

Atmosphärische und ozeanische Einflüsse auf die Rotation der Erde - Nummerische Untersuchungen mit einem dynamischen Erdsystemmodell / Florian Seitz (2004)

Permalink

Journées 2000 Systèmes de référence spatio-temporels, J 2000 / Nicole Capitaine (2000)  

Permalink

Apport de l'analyse non linéaire à l'étude géophysique de la rotation de la Terre / V. Frede (1999)

Permalink

Zur Energie der Chandler Polschwankung / H. Lenhardt (1990)

Permalink

Prediction of polar motion from air and water excitations / J. Vondrak (1989)

Permalink

Vergleichende Analyse der Ergebnisse zweier astronomischer Beobachtungsreihen und einer dopplermessreihe zur Bestimmung von Breiten- und Längenvariationen über eine Chandlerperiode / K. Kaniuth (1985)

Permalink

Contribution à l'interprétation du mouvement du pôle par des phénomènes géophysiques, météorologiques et océanographiques / S. Daillet (1981)

Permalink

Secular variation of pole tide / S. Daillet (1979)

Permalink

Polar motion spectra based upon Doppler, IPMS and BIH Data / M.A. Graber (1975)

Permalink