Detection Of Vertical Temporal Behaviour Of Igs Stations In Canada Using Least Squares Spectral Analysis

Unambiguous, consistent and homogeneous GPS station coordinates are the fundamental requirement in the appropriate determination of geodetic velocities that are often used for the derivation of geodetic and geophysical models for a variety of applications [Segall and Davis, Ann Rev Earth Planet Sci 23:201-336, 1997]. Because of this, there have been significant efforts to improve the modeling and parameterization of global GPS solutions in order to get stable and homogeneous positions and velocities. This paper presents a study aiming at detecting least-squares spectral peaks present at the best available (at the time) IGS weekly vertical component time series of five permanent stations in Canada. These peaks are the result of short and long term effects of mismodelled and unmodelled geophysical phenomena on the height. The LSSA approach is used. Results show strong periodic constituents in the LSSA spectrum below or at the 1 year window but most notably constituents with periods longer than a year.