Sea-level Variations and Geocentre Motions

Halfdan P. Kierulf(1) and Hans-Peter Plag(1,2)

(1) Norwegian Mapping Authority
3507 Honefoss, Norway
(2) Nevada Bureau of Mines and Geology and Seismological Laboratory
University of Nevada, Reno, Mailstop 178, Reno, NV 89557, USA


The European Sea Level Service (ESEAS) has the objective to provide information about sea-level and sea-level variations.

Tide gauges may only measure sea-level changes relative to land. To separate absolute changes in sea-level from vertical land movements and to measure sea-level changes relative to the earths geocentre, several of the ESEAS tide gauges are colocated with CGPS stations.

However results from the different ESEAS CGPS ACs show significant differences. This may partly be explained by different realisations of the reference frame and especially differnet realisations of the geocentre.

We will in this presentation look at the different realisations of the geocentre and how that influence the measurements of vertical land movement.