Published online by Cambridge University Press: 03 August 2017
A continuous three year series of observations with the model TT40 superconducting gravimeter has been analysed for all frequency domains. The frequency of the nearly diurnal free wobble (NDFW) (1 + 1/(431.2 ± 3.2) cycles/sid.d.) and a damping factor (6208.5 days) are derived from this dataset. These results are not in agreement with the values predicted by the theoretical model presented by Wahr but match very closely the values derived from VLBI observations. A similar study of long period effects suggests furthermore that there is a strog correlation with the polar motion observed by other techniques. By comparing different drift models with respect to the ultra-long period of the gravity variations it is shown that the observed Chandler effect is not principally subjected to this type of instrumentally dependent parameter.