HR: 11:35h
AN: G42A-06 INVITED     [Abstracts]
TI: Short-period Variations of the Earth Rotation Parameters Observed by Very Long Baseline Interferometry
AU: * Schuh, H
EM: harald.schuh@tuwien.ac.at
AF: IGG, Vienna University of Technology, Gusshausstrasse 27-29, Vienna, 1040, Austria
AU: Artz, T
EM: thomas.artz@uni-bonn.de
AF: Institute for Geodesy and Geoinformation of the University of Bonn (Department Geodesy), Nussallee 17, Bonn, 53115, Germany
AU: Nothnagel, A
EM: nothnagel@uni-bonn.de
AF: Institute for Geodesy and Geoinformation of the University of Bonn (Department Geodesy), Nussallee 17, Bonn, 53115, Germany
AU: Mendes Cerveira, P J
EM: mendes@mars.hg.tuwien.ac.at
AF: IGG, Vienna University of Technology, Gusshausstrasse 27-29, Vienna, 1040, Austria
AB: High-frequency polar motion and universal time variations are obtained from Very Long Baseline Interferometry (VLBI). The goal is to detect short-period and episodic events with signatures below the 100 microarcseconds (7.5 microseconds) level. Ter-diurnal variations in the order of 40 microarcseconds in polar motion have been reported during the VLBI campaign CONT02, from October 16 to 31, 2002. But, no geophysical explanation with similar amplitudes was provided. To resolve this enigma, we re-processed the VLBI data obtained during the CONT96, CONT02, and CONT05 campaigns using identical an the most recent reduction models. Two independent software packages were used, OCCAM61E and CALC SOLVE, to assure robustness of the Earth rotation parameters (ERP) estimated with semi-hourly resolution over the fortnightly data sets. The long wavelength signal was removed by a smooth function from the final ERP. Jumps in the ERP values at session boundaries were identified. A heuristic and Fourier frequency analysis shows no significant ter-diurnal periods. In addition, this high-frequency analysis allows to detect incorrect daily ERP values in the International Earth Rotation and reference Systems (IERS) C04 series.
DE: 1239 Earth rotation variations
DE: 1294 Instruments and techniques
DE: 1295 Integrations of techniques
SC: Geodesy [G]
MN: 2007 Joint Assembly