Changes in the position of the geocentre due to variations in sea-level

The hydrostatic equation is used to show that load departures on the ocean floor due solely to the oceans may be determined from the excess of recorded over steric sea-level and a representative density. The effect of these departures on the position of the geocentre is estimated using formulae derived by Stolz (1976) and data compiled from Pattullo et al. (1955) and Pattullo (1960; 1963). The resulting maximum seasonal position change turns out to be about 2mm. Addition of the results calculated here and those published earlier by Stolz (1976) indicates that the maximum geocentre motion due to seasonal variations in air mass, ground water and sea-level is about 5mm, which is about an order smaller than the point-coordination accuracy modern high-precision geodesy aims to achieve.