16 Oct 2013
Système d'Observation du Niveau des Eaux Littorales (SONEL) recently launched a new web page that allows one to explore the effect of vertical land motion on sea level rates recorded at tide gauges. This website uses the rates displayed on our sea level trends page in combination with land motion rates determined from GNSS (predominantly GPS) observations. The tide gauge (commonly called relative sea level) rates with the vertical land motion removed are typically called geocentric (or absolute) sea level. The geocentric sea level rates can then be compared to results derived from altimetry. The maps allow one to switch between the two types of observations.
Land motion is an important component to understanding sea level changes at the coasts around the world. One of the most notable changes when switching the maps between relative and geocentric sea level occurs to rates observed in Sweden and Finland. Tide gauges show a very large sea level fall. However, after removing the observed land uplift in the region, the geocentric sea level rates across Europe look much more similar.