Sea level and its change has been measured for more than a century. Especially, for nations with long coastlines and important coastal industry observations of tides, extremes, and long-term changes have strong economic impacts.
Today, the observed sea level rise (SLR) is largely associated with climate related changes. To find the patterns and fingerprints of those changes, different monitoring techniques have been developed. Some of them are local, e.g. tide gauges, others are global, e.g., radar altimetry. In many areas, the slow long-term rise in sea level is superimposed by artificial and sometimes natural changes, which might have much higher rates in relative sea level rise. Reasons for that are e.g., groundwater, gas or oil extraction in near-shore areas or changes in the coastal habitat.
GGOS and it’s services contribute in many ways to the monitoring of the sea level. This ranges from tide gauge observations, estimation of gravity changes, GNSS control of tide gauges or the maintenance of the International Reference Frame.
Theme 3 of GGOS establishes a platform and will be a forum to researchers and authorities for estimating and predicting global and local sea level changes in a 10- to 30-year time horizon.
Global Mean Sea Level (middle, vertical scale exaggerated) and some supporting methods