H. Schuh, O. Titov
: Short-period variations of the Earth rotation parameters as seen by VLBI
 
                   ABSTRACT
 
 
Modern geodetic VLBI experiments provide very accurate
results of polar motion and UT1-UTC. More than 300
VLBI experiments (NEOS-A from 1993 till 1998, CONT'96, CORE) were
analysed by the OCCAM 3.4 VLBI software using the least-squares
collocation method (LSCM). The LSCM allows to estimate the Earth
rotation parameters with a temporal resolution of 3-7 minutes. Wavelet
transformations of the UT1-UTC and polar motion
time series obtained by the VLBI solutions were done. Several
irregular quasi-periodic variations were found besides the well known
diurnal and semidiurnal periods. In many UT1-UTC data sets periods
around 8 hours and between 5 and 7 hours can be seen. The results of
two parallel VLBI sessions which took place since 1998 were compared
in the high-frequency range. The wavelet analysis reveals interesting
patterns in polar motion, too.
 
-----------------------------------------------------------------------
In Proceedings of the 13th Working Meeting on European VLBI for Geodesy
and Astrometry, Viechtach, 1999
 
Keywords: Earth rotation, polar motion, UT1, wavelet analysis