Global analysis of the GGP superconducting gravimeters network for the estimation of the pole tide gravimetric amplitude factor
Ducarme, B.; Venedikov, A.P.; Arnoso, J.; Chen, X.D.; Sun, H.P.; Vieira, R. (2006). Global analysis of the GGP superconducting gravimeters network for the estimation of the pole tide gravimetric amplitude factor. J. Geodyn. 41(13): 334344. dx.doi.org/10.1016/j.jog.2005.08.007
In: Journal of Geodynamics. Elsevier Science: Amsterdam. ISSN 02643707; eISSN 18791670, meer
 
Author keywords 
pole tide; gravimetric factor; superconducting gravimetry; GGP network; 
Auteurs   Top 
 Ducarme, B.
 Venedikov, A.P.
 Arnoso, J.

 Chen, X.D.
 Sun, H.P.
 Vieira, R.


Abstract 
The tidal records of superconducting gravimeters (SG) in nine stations are analyzed, in order to determine the gravity variation due to the polar motion. In a first step the tidal constituents are estimated and subtracted from the original data, together with the estimated atmospheric pressure effects, by the computer program VAV. The data so obtained are submitted to a regression analysis by a specially developed program POLAR, whose aim is the estimation of the gravimetric amplitude factor d_{CH} of the pole tide and its time shift with respect to the theoretical gravity signal due to the polar motion. The procedure includes an optimization of various parameters of the regression model, as well as a detection and elimination of the anomalous portions of the records. The analysis has been first applied separately on each one of the nine series. Most of the stations provided a d_{CH} factor between 1.17 and 1.19 with mean square deviation close to 1%. Further all series have been submitted to a global analysis through which a common value of the d_{CH} factor has been estimated. No significant global time shift has been found. The global adjustment values are d_{CH} = 1. 1816 +/ 0.0047 or 1. 1797 +/ 0.0047, depending on the way the time shift is introduced, while the simple arithmetic mean of the stations is 1. 1788 +/ 0.0040. This result differs considerably from the values predicted by Earth response models, e.g. from delta = 1. 158 obtained for the annual period through the nonhydrostatic anelastic model, usually called DDW99. The discrepancy is due to the indirect effects of the ocean tides. A preliminary correction scheme based on an equilibrium ocean pole tide is indeed reducing the globally adjusted d_{CH} factor to 1.1612 or 1.1593 and the arithmetic mean to 1.1605. 
