No CrossRef data available.
Published online by Cambridge University Press: 12 April 2016
The 0.042-day Earth rotation data (diurnal and semidiurnal) computed by the International GPS Service were used to analyze the daily/sub-daily variations of polar motion (PM) and length of day (LOD). Systematic and advanced spectral analytical investigations of the degree of periodic variability have been carried out. They show that the prominent periodical components can be found at the tidal frequencies of zonal, tesseral and sectorial waves. These investigations should give better insight into the physical processes, which influence Earth orientation (i.e. due to the atmospheric and oceanic motions, tidal forces etc.). It should be the basis for the detailed modeling of excitation functions in the sub-diurnal range of the high-frequency spectrum.