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This work is devoted to investigation of low frequency variations in Polarmotion (PM). It has been shown that the main PM features can be effectivelyinvestigated using not only time series of the Pole coordinates, but also usingseries of latitude variations obtained from observations at one observatory.Such an approach allows us to increase the length of observation seriesavailable for analysis. In our study, we extended the IERS PM series back to1840. We investigate trends and (quasi) harmonic oscilla-tions with periodsfrom one year to decades. The main results were obtained making use of theSingular Spectrum Analysis. Other methods were also used for specific analysisand independent check. The most interesting results are detection of two newlarge phase jumps in the 1840s and 2000s, and revealing of 80-year period inthe PM variations.

Analysis of Polar Motion Variations from 170-year Observation Series