Jian‐Qiao Xu

European Tidal Gravity Observations: Comparison With Earth Tide Models And Estimation Of The Free Core Nutation (Fcn) Parameters

The data of sixteen West European tidal gravity stations have been reprocessed. The tidal gravity factors have been corrected for ocean loading effect using the mean of 9 different ocean tides models with different grid size (0.5 ◦ ,0 .25 ◦ and 0.125 ◦ ). For the principal tidal waves O1 and M2 the standard deviation of the corrected amplitude factors δc is lower than 0.1%. For O1 the value δc = 1.15340 ± 0.00023 lies between the Dehant, Defraigne and Wahr, 1999 (DDW99) elastic model and the Mathews, 2001 (MAT01) inelastic model. For M2 the value δc = 1.16211 ± 0.00020 fits very well the DDW99 and the MAT01 inelastic models. For K1 the mean result δc = 1.13525 ± 0.00032 (7 Global Geodynamics Project stations and Pecny) fits the MAT01 model to better than 0.05%. We determine the FCN parameters using either generalized least-squares or a Bayesian approach and find values between 428 and 432 sidereal days for the eigenperiod and quality factor Q values around 15,000.