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Geodynamic research at the Department of Planetary Geodesy, SRC PAS

Brzeziński A., Jóźwik M., Kaczorowski M., Kalarus M., Kasza D., Kosek W., Nastula J., Szczerbowski Z., Wińska M., Wronowski R., Zdunek R., Zieliński J. B.

Reports on Geodesy and Geoinformatics

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2016

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Vol. 100

131--147

EN

The Department of Planetary Geodesy of the Space Research Centre PAS has been conducting research on a broad spectrum of problems within a field of global dynamics of the Earth. In this report we describe the investigations on selected subjects concerning polar motion (modeling and geophysical interpretation of the Chandler wobble, hydrological excitation of seasonal signals, search for optimal prediction methods), tectonic activity in the region of the Książ Geodynamic Laboratory of the SRC, and finally the new joint Polish-Italian project GalAc analyzing feasibility and usefulness of equipping second-generation Galileo satellites with accelerometers.

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Assessment of the Global and Regional Land Hydrosphere and Its Impact on the Balance of the Geophysical Excitation Function of Polar Motion

Wińska M., Nastula J., Kołaczek B.

Acta Geophysica

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2016

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Vol. 64, no. 1

270--292

EN

The impact of continental hydrological loading from land water, snow and ice on polar motion excitation, calculated as hydrological angular momentum (HAM), is difficult to estimate, and not as much is known about it as about atmospheric angular momentum (AAM) and oceanic angular momentum (OAM). In this paper, regional hydrological excitations to polar motion are investigated using monthly terrestrial water storage data derived from the Gravity Recovery and Climate Experiment (GRACE) mission and from the five models of land hydrology. The results show that the areas where the variance shows large variability are similar for the different models of land hydrology and for the GRACE data. Areas which have a small amplitude on the maps make an important contribution to the global hydrological excitation function of polar motion. The comparison of geodetic residuals and global hydrological excitation functions of polar motion shows that none of the hydrological excitation has enough energy to significantly improve the agreement between the observed geodetic excitation and geophysical ones.

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Earth rotation and geodynamics

Bogusz J., Brzezinski A., Kosek W., Nastula J.

Geodesy and Cartography

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2015

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Vol. 64, no. 2

201--242

EN

This paper presents the summary of research activities carried out in Poland in 2011-2014 in the field of Earth rotation and geodynamics by several Polish research institutions. It contains a summary of works on Earth rotation, including evaluation and prediction of its parameters and analysis of the related excitation data as well as research on associated geodynamic phenomena such as geocentre motion, global sea level change and hydrological processes. The second part of the paper deals with monitoring of geodynamic phenomena. It contains analysis of geodynamic networks of local, and regional scale using space (GNSS and SLR) techniques, Earth tides monitoring with gravimeters and water-tube hydrostatic clinometer, and the determination of secular variation of the Earth’ magnetic field.

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Chronology of Developments of Geodynamic Investigations in XIX and XX Centuries

Kolaczek B., Nastula J.

Reports on Geodesy

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2012

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z. 1/92

103--107

EN

There were big developments of geodynamic investigations in the XX century. In the paper the scope of the chronology of developments of geodynamic investigations from the end of XIX century until the beginning of XXI century is presented. It is presented in the following six areas: 1. Theory 2. Establishment of definitions and models 3. Analysis of observations 4. Celestial reference frames 5. Terrestrial reference frames 6. Organizations of investigations

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Comparison of the geophysical excitations of polar motion from the period: 1980.0-2009.0

Nastula J., Paśnicka M., Kołaczek B.

Acta Geophysica

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2011

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Vol. 59, no. 3

561-577

EN

In this study we compared contributions to polar motion excitation determined separately from each of three kinds of geophysical data: atmospheric pressure, equivalent water height estimated from hydrological models, and harmonic coefficients of the Earth gravity field obtained from Gravity Recovery and Climate Experiment (GRACE). Hydrological excitation function (Hydrological Angular Momentum - HAM) has been estimated from models of global hydrology, based on the observed distribution of surface water, snow, ice, and soil moisture. In our consideration we used several global models of land hydrosphere and models of Atmospheric Angular Momentum (AAM) and Oceanic Angular Momentum (OAM). All of them were compared with observed Geodetic Angular Momentum (GAM). The spectra of the following excitation functions of polar motion: GAM, AAM+OAM, AAM+OAM+HAM, GAM-AAM-OAM residual geodetic excitation function, and HAM were computed too. The time variable spectra of geodetic, gravimetric, and the sum of atmospheric, oceanic, and hydrological excitation functions are also presented. Phasor diagrams of the seasonal components of polar motion excitation functions of all HAM excitation functions as well as of two GRACE solutions: Center for Space Research (CSR), Centre National d'Etudes Spatiales/Groupe de Recherche en Geodesie Spatiale (CNES/GRGS) were determined and discussed.

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Spectral characteristic of polar motion in the 2005-2006 and 1999-2000 winters seasons

Nastula J., Kolaczek B.

Artificial Satellites : Journal of Planetary Geodesy

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2007

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Vol. 42, No. 1

1--7

EN

The Earth's pole moves on the Earth's surface along the spiral curve known as "polhody". Polhody computed from the IERS C04 pole coordinates were compared with those computed after removing successively oscillations with periods shorter than 150, 30, 10, 2 days. The comparison of these polhody show that the loops in the winter seasons of 2005- 2006 and 1999-2000 are caused by the oscillations of polar motion with periods shorter than 30 days. These short periodical oscillations of geodetic excitation function of polar motion were correlated with those of the atmospheric and oceanic excitation functions. There are high correlations with coefficients equal to 0.8-0.9 during epochs when loops occur.