{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,12]],"date-time":"2026-09-12T00:19:54Z","timestamp":1789172394642,"version":"build-2803163510"},"reference-count":60,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2021,12,30]],"date-time":"2021-12-30T00:00:00Z","timestamp":1640822400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>Similar to seasonal and intraseasonal variations in polar motion (PM), interannual variations are also largely caused by changes in the angular momentum of the Earth\u2019s geophysical fluid layers composed of the atmosphere, the oceans, and in-land hydrologic flows (AOH). Not only are inland freshwater systems crucial for interannual PM fluctuations, but so are atmospheric surface pressures and winds, oceanic currents, and ocean bottom pressures. However, the relationship between observed geodetic PM excitations and hydro-atmospheric models has not yet been determined. This is due to defects in geophysical models and the partial knowledge of atmosphere\u2013ocean coupling and hydrological processes. Therefore, this study provides an analysis of the fluctuations of PM excitations for equatorial geophysical components \u03c71 and \u03c72 at interannual time scales. The geophysical excitations were determined from different sources, including atmospheric, ocean models, Gravity Recovery and Climate Experiment (GRACE) and GRACE Follow-On data, as well as from the Land Surface Discharge Model. The Multi Singular Spectrum Analysis method was applied to retain interannual variations in \u03c71 and \u03c72 components. None of the considered mass and motion terms studied for the different atmospheric and ocean models were found to have a negligible effect on interannual PM. These variables, derived from different Atmospheric Angular Momentum (AAM) and Oceanic Angular Momentum (OAM) models, differ from each other. Adding hydrologic considerations to the coupling of AAM and OAM excitations was found to provide benefits for achieving more consistent interannual geodetic budgets, but none of the AOH combinations fully explained the total observed PM excitations.<\/jats:p>","DOI":"10.3390\/rs14010147","type":"journal-article","created":{"date-parts":[[2021,12,30]],"date-time":"2021-12-30T23:29:07Z","timestamp":1640906947000},"page":"147","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["A Comparative Study of Interannual Oscillation Models for Determining Geophysical Polar Motion Excitations"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-5265-3028","authenticated-orcid":false,"given":"Ma\u0142gorzata","family":"Wi\u0144ska","sequence":"first","affiliation":[{"name":"Faculty of Civil Engineering, Warsaw University of Technology, 00-614 Warsaw, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2021,12,30]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"253","DOI":"10.1029\/93GL00130","article-title":"Excitation of Earth\u2019s polar motion by atmospheric angular momentum variations: 1980\u20131990","volume":"20","author":"Chao","year":"1993","journal-title":"Geophys. Res. Lett."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"476","DOI":"10.1038\/35126","article-title":"Oceanic signals in observed motions of the Earth\u2019s pole of rotation","volume":"391","author":"Ponte","year":"1998","journal-title":"Nature"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"4586","DOI":"10.1002\/jgrb.50322","article-title":"Recent estimates of Earth-atmosphere interaction torques and their use in studying polar motion variability","volume":"118","author":"Shindelegger","year":"2013","journal-title":"J. Geophys. Res. Solid Earth"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"B10406","DOI":"10.1029\/2009JB007127","article-title":"Seasonal polar motion excitation from numerical models of atmosphere, ocean, and continental hydrosphere","volume":"115","author":"Dobslaw","year":"2010","journal-title":"J. Geophys. Res. Solid Earth"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"235","DOI":"10.1016\/j.jog.2009.09.021","article-title":"Seasonal excitation of polar motion estimated from recent geophysical models and observations","volume":"48","author":"Nastula","year":"2009","journal-title":"J. Geodyn."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Bizouard, C. (2020). Geophysical Modelling of the Polar Motion, De Gruyter.","DOI":"10.1515\/9783110298093"},{"key":"ref_7","first-page":"B09101","article-title":"Absolute plate motions in a reference frame defined by moving hotspots in the Pacific, Atlantic and Indian Oceans","volume":"117","author":"Doubrovine","year":"2012","journal-title":"J. Geophys. Res."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"577","DOI":"10.1146\/annurev-earth-040610-133404","article-title":"Ice age Earth rotation","volume":"39","author":"Mitrovica","year":"2011","journal-title":"Annu. Rev. Earth Planet. Sci."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"\u015aliwi\u0144ska, J., Nastula, J., Dobslaw, H., and Dill, R. (2020). Evaluating Gravimetric Polar Motion Excitation Estimates from the RL06 GRACE Monthly-Mean Gravity Field Models. Remote Sens., 12.","DOI":"10.3390\/rs12060930"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.jog.2016.03.011","article-title":"A comparison of interannual hydrological polar motion excitation from GRACE and geodetic observations","volume":"99","author":"Meyrath","year":"2016","journal-title":"J. Geodyn."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"2625","DOI":"10.1002\/grl.50552","article-title":"Rapid ice melting drives Earth\u2019s pole to the east","volume":"40","author":"Chen","year":"2013","journal-title":"Geophys. Res. Lett."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"13404","DOI":"10.1029\/2019JB018541","article-title":"Interannual Oscillations in Earth Rotation","volume":"124","author":"Chen","year":"2019","journal-title":"J. Geophys. Res. Solid Earth"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"433","DOI":"10.1002\/wics.101","article-title":"Principal component analysis","volume":"2","author":"Abdi","year":"2010","journal-title":"Wiley Interdiscip. Rev. Comput. Stat."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"3-1","DOI":"10.1029\/2000RG000092","article-title":"Advanced spectral methods for climatic time series","volume":"40","author":"Ghil","year":"2002","journal-title":"Rev. Geophys."},{"key":"ref_15","first-page":"400","article-title":"Multivariate Extension of the Singular Spectrum Analysis A New Tool in Understanding the Intraseasonal-Oscillation (ISO) of Philippines Summer Monsoon and its Association with Extreme Rainfall Events","volume":"22","author":"Luzano","year":"2020","journal-title":"Glob. NEST J."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"V25","DOI":"10.1190\/1.3552706","article-title":"Simultaneous seismic data denoising and reconstruction via multichannel singular spectrum analysis","volume":"76","author":"Oropeza","year":"2011","journal-title":"Geophysics"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"95","DOI":"10.1016\/0167-2789(92)90103-T","article-title":"Singular-spectrum analysis: A toolkit for short, noisy chaotic signals","volume":"58","author":"Vautard","year":"1992","journal-title":"Phys. D Nonlinear Phenom."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"147","DOI":"10.1186\/s40623-021-01477-2","article-title":"Analysis and prediction of polar motion using MSSA method","volume":"73","author":"Jin","year":"2021","journal-title":"Earth Planets Space"},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Jin, X., Liu, X., Guo, J., and Shen, Y. (2021). Multi-Channel Singular Spectrum Analysis on Geocenter Motion and Its Precise Prediction. Sensors, 21.","DOI":"10.3390\/s21041403"},{"key":"ref_20","unstructured":"Sarkar, S. (1986). Nonlinear Phenomena and Chaos, Adam Hilger Ltd."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"217","DOI":"10.1016\/0167-2789(86)90031-X","article-title":"Extracting qualitative dynamics from experimental data","volume":"20","author":"Broomhead","year":"1986","journal-title":"Phys. D Nonlinear Phenom."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"395","DOI":"10.1016\/0167-2789(89)90077-8","article-title":"Singular spectrum analysis in nonlinear dynamics, with applications to paleoclimatic time series","volume":"35","author":"Vautard","year":"1989","journal-title":"Phys. D Nonlinear Phenom."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"265","DOI":"10.1007\/978-3-642-00860-3_41","article-title":"The Combined Solution C04 for Earth Orientation Parameters Consistent with International Terrestrial Reference Frame 2005","volume":"Volume 134","author":"Drewes","year":"2009","journal-title":"Geodetic Reference Frames"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"239","DOI":"10.1016\/B978-044452748-6\/00057-2","article-title":"3.09\u2014Earth Rotation Variations\u2014Long Period","volume":"3","author":"Gros","year":"2007","journal-title":"Treatise Geophys."},{"key":"ref_25","first-page":"31","article-title":"Atmospheric Angular Momentum Fluctuations, Length-of-Day Changes and Polar Motion","volume":"387","author":"Barnes","year":"1983","journal-title":"Proc. R. Soc. Lond."},{"key":"ref_26","doi-asserted-by":"crossref","unstructured":"Dickman, S.R. (2003). Evaluation of \u201ceffective angular momentum function\u201d formulations with respect to core-mantle coupling. J. Geophys. Res. Solid Earth, 108.","DOI":"10.1029\/2001JB001603"},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Smith, D.E., and Turcotte, D.L. (1993). Variations in the Orientation of the Earth. Contributions of Space Geodesy to Geodynamics, American Geophysical Union.","DOI":"10.1029\/GD024"},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Lambeck, K. (1980). The Earth\u2019s Variable Rotation: GeophysicalCauses and Consequences, Cambridge University Press.","DOI":"10.1017\/CBO9780511569579"},{"key":"ref_29","unstructured":"Gross, R. (2013, January 17\u201321). Theory of Earth Rotation Variations. Proceedings of the VIII Hotine-Marussi Symposium on Mathematical Geodesy, Rome, Italy."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"195","DOI":"10.1186\/s40623-018-0968-4","article-title":"Mass related excitation of polar motion: An assessment of the new RL06 GRACE gravity field models","volume":"70","author":"Schmidt","year":"2018","journal-title":"Earth Planets Space"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"413","DOI":"10.1016\/j.geog.2017.01.008","article-title":"IGS polar motion measurement accuracy","volume":"8","author":"Ray","year":"2017","journal-title":"Geod. Geodyn."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"437","DOI":"10.1175\/1520-0477(1996)077<0437:TNYRP>2.0.CO;2","article-title":"The NCEP\/NCAR 40-Year Reanalysis Project","volume":"77","author":"Kalnay","year":"1996","journal-title":"Bull. Am. Meteorol. Soc."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"67","DOI":"10.1175\/1520-0477(1993)074<0067:TSBFAA>2.0.CO;2","article-title":"The Sub-bureau for Atmospheric Angular Momentum of the International Earth Rotation Service: A Meteorological Data Center with Geodetic Applications","volume":"74","author":"Salstein","year":"1993","journal-title":"Bull. Am. Meteorol. Soc."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"D12108","DOI":"10.1029\/2005JD006608","article-title":"Revised atmospheric excitation function series related to Earth\u2019s variable rotation under consideration of surface topography","volume":"111","author":"Zhou","year":"2006","journal-title":"J. Geophys. Res. Atmos."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"B02403","DOI":"10.1029\/2009JB006635","article-title":"Hydrological and oceanic effects on polar motion from GRACE and models","volume":"115","author":"Jin","year":"2010","journal-title":"J. Geophys. Res. Solid Earth"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"25647","DOI":"10.1029\/1999JC900193","article-title":"Assimilation of TOPEX\/Poseidon altimeter data into a global ocean circulation model: How good are the results?","volume":"25","author":"Fukumori","year":"1999","journal-title":"J. Geophys. Res."},{"key":"ref_37","unstructured":"Fukumori, I., Lee, T., Menemenlis, D., Fu, L.-L., Cheng, B., Tang, B., Xing, Z., and Giering, R. (2000, January 15\u201317). A dual assimilation system for satellite altimetry. Proceedings of the Joint TOPEX\/Poseidon and Jason\u20141 Science Working Team Meeting, Miami, FL, USA."},{"key":"ref_38","doi-asserted-by":"crossref","unstructured":"Gross, R.S., Fukumori, I., and Menemenlis, D. (2003). Atmospheric and oceanic excitation of the Earth\u2019s wobbles during 1980\u20132000. J. Geophys. Res., 108.","DOI":"10.1029\/2002JB002143"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"1047","DOI":"10.1016\/j.asr.2017.11.044","article-title":"Predicting Earth orientation changes from global forecasts of atmosphere-hydrosphere dynamics","volume":"4","author":"Dobslaw","year":"2018","journal-title":"Adv. Space Res."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"e2020EA001563","DOI":"10.1029\/2020EA001563","article-title":"Intraseasonal variations in atmospheric and oceanic excitation of length-of-day","volume":"8","author":"Yu","year":"2021","journal-title":"Earth Space Sci."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"801","DOI":"10.1093\/gji\/ggz201","article-title":"Seasonal Variations in Global Mean Sea-Level and Consequences on the Excitation of Length-of-Day Changes","volume":"218","author":"Dill","year":"2019","journal-title":"Geophys. J. Int."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"422","DOI":"10.1002\/jame.20023","article-title":"Characteristics of the ocean simulations in the Max Planck Institute Ocean Model (MPIOM) the ocean component of the MPI-Earth system model","volume":"2","author":"Jungclaus","year":"2013","journal-title":"J. Adv. Modelin Earth Syst."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"1503","DOI":"10.1029\/2000JD900568","article-title":"Validation of the hydrological cycle of ECMWF and NCEP reanalyses using the MPI hydrological discharge model","volume":"106","author":"Hagemann","year":"2001","journal-title":"J. Geophys. Res."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"349","DOI":"10.1007\/s00382-003-0349-x","article-title":"Improving a subgrid runoff parameterization scheme for climate models by the use of high resolution data derived from satellite observations","volume":"21","author":"Hagemann","year":"2003","journal-title":"Clim. Dyn."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"B06205","DOI":"10.1029\/2007JB005397","article-title":"Low degree gravity changes from GRACE, earth rotation, geophysical models and satellite laser ranging","volume":"113","author":"Chen","year":"2008","journal-title":"J. Geophys. Res. Solid Earth"},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"263","DOI":"10.1093\/gji\/ggx302","article-title":"A new high-resolution model of non\u2013tidal atmosphere and ocean mass variability for de-aliasing of satellite gravity observations: AOD1B RL06","volume":"211","author":"Dobslaw","year":"2017","journal-title":"Geophys. J. Int."},{"key":"ref_47","doi-asserted-by":"crossref","unstructured":"\u015aliwi\u0144ska, J., Wi\u0144ska, M., and Nastula, J. (2020). Preliminary Estimation and Validation of Polar Motion Excitation from Different Types of the GRACE and GRACE Follow-On Missions Data. Remote Sens., 12.","DOI":"10.3390\/rs12213490"},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"934","DOI":"10.1016\/j.csda.2013.04.009","article-title":"Basic Singular Spectrum Analysis and forecasting with R","volume":"71","author":"Golyandina","year":"2014","journal-title":"Comput. Stat. Data Anal."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"7873","DOI":"10.1175\/JCLI-D-15-0100.1","article-title":"Monte Carlo Singular Spectrum Analysis (SSA) Revisited: Detecting Oscillator Clusters in Multivariate Datasets","volume":"28","author":"Growth","year":"2015","journal-title":"J. Clim."},{"key":"ref_50","unstructured":"Golyandina, N., and Stepanov, D. (July, January 26). SSA-Based approaches to analysis and forecast of multidimentional time series. Proceedings of the 5th St. Petersburg Workshop on Simulation, Saint Petersburg, Russia."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"210","DOI":"10.1175\/1520-0469(1994)051<0210:SOLFOA>2.0.CO;2","article-title":"Spells of low-frequency oscillations and weather regimes in the northern hemisphere","volume":"51","author":"Plaut","year":"1994","journal-title":"J. Atmos. Sci."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"1461","DOI":"10.1007\/s00190-017-1036-8","article-title":"Hydrological excitation of polar motion by different variables from the GLDAS models","volume":"91","author":"Winska","year":"2017","journal-title":"J. Geod."},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"149","DOI":"10.1046\/j.1365-246X.2000.00069.x","article-title":"Hydrological and oceanic excitations to polar motion andlength-of-day variation","volume":"141","author":"Chen","year":"2000","journal-title":"Geophys. J. Int."},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"174396","DOI":"10.1155\/2011\/174396","article-title":"Hydrological Excitation of Polar Motion Derived from GRACE Gravity Field Solutions","volume":"2011","author":"Seoane","year":"2011","journal-title":"Int. J. Geophys."},{"key":"ref_55","first-page":"27","article-title":"Time variable band pass filter spectra of real and complex-valued polar motion series","volume":"30","author":"Kosek","year":"1995","journal-title":"Artif. Satell. Planet. Geod."},{"key":"ref_56","doi-asserted-by":"crossref","first-page":"12417","DOI":"10.1029\/2000JD900101","article-title":"Wind contributions to the Earth\u2019s angular momentum budgets in seasonal variation","volume":"105","author":"Aoyama","year":"2000","journal-title":"J. Geophys. Res."},{"key":"ref_57","doi-asserted-by":"crossref","unstructured":"Masaki, Y. (2008). Wind field differences between three meteorological reanalysis data sets detected by evaluating atmospheric excitation of Earth rotation. J. Geophys. Res., 113.","DOI":"10.1029\/2007JD008893"},{"key":"ref_58","doi-asserted-by":"crossref","first-page":"95","DOI":"10.1007\/s11200-018-1028-z","article-title":"Assessing hydrological signal in polar motion from observations and geophysical models","volume":"63","year":"2019","journal-title":"Studia Geophys. Et Geod."},{"key":"ref_59","unstructured":"Dobslaw, H., and Dill, R.E. (2019). Effective Angular Momentum Functions from Earth System Modelling at GeoForschungsZentrum in Potsdam, GFZ. Available online: http:\/\/rz-vm115.gfz-potsdam.de:8080\/repository."},{"key":"ref_60","doi-asserted-by":"crossref","first-page":"2361","DOI":"10.1029\/94GL02285","article-title":"Interannual variations in the Earth\u2019s polar motion for 1963\u20131991: Comparison with atmospheric angular momentum over 1980\u20131991","volume":"21","author":"Cazenave","year":"1994","journal-title":"Geophys. Res. Lett."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/14\/1\/147\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T07:55:51Z","timestamp":1760169351000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/14\/1\/147"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,12,30]]},"references-count":60,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2022,1]]}},"alternative-id":["rs14010147"],"URL":"https:\/\/doi.org\/10.3390\/rs14010147","relation":{},"ISSN":["2072-4292"],"issn-type":[{"value":"2072-4292","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,12,30]]}}}