Estimation of the pole tide gravimetric factor at the chandler period through wavelet filtering
نویسندگان
چکیده
S U M M A R Y Wavelet analysis for filtering is used to improve estimation of gravity variations induced by Chandler wobble. This method eliminate noise in superconducting gravimeter (SG) records with bandpass filters derived from Daubechies wavelet. The SG records at four European stations (Brussels, Membach, Strasbourg and Vienna) are analysed in this study. First, the earth tidal constituents are removed from the observed data by using synthetic tides, then the gravity residuals are filtered into a narrow period band of 256–512 d by a wavelet bandpass filter. These data are submitted to three regression analysis methods for estimating the gravimetric factor of the Chandler wobble. After processing by wavelet filtering, SG records can provide amplitude factors δ and phase lags κ of the Chandler wobble with much smaller mean square deviation (MSD) than these provided by former studies. It is mainly because the wavelet method can effectively eliminate instrumental drift and provide smoothed data series for the regression analysis.
منابع مشابه
OBSERVATIONS AND INTERPRETATION OF THE POLE TIDE by STEPHEN
Spectral analysis has been applied to virtually all of the world's long tide records in a search for a signal at the frequency of the Chandler wobble. In Northern Europe the amplitudes are two to ten times greater than equilibrium. Hints of a pole tide are observed at a few other stations, but at most locations the tide does not stand out above the noise continuum. A host of theoretical explana...
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