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.
Sea level rise and its impact on human habitats and economic well being is one of the key issues in the climate change discussion. In recent years this topic has received considerable and growing attention by the general public, engineers, researchers, and policy makers and calls for multi-disciplinary research. In 2010 GGOS has identified sea level change as one of the cross-cutting themes for geodesy and established this topic as one of its Focus Areas. The primary task of Focus Area 3 is to demonstrate the value of different geodetic techniques available under the umbrella of GGOS to the mitigation of sea level rise including studies of the impacts of its change over the world’s coastal regions and islands, and to support practical applications such as sustainability. Focus Area 3 interacts with the other Focus Areas as well as with the related Committees and Working Groups of the GGOS Bureaus. Close cooperation is established and will be intensified with groups and organizations working in related fields. One major topic is the identification of gaps and their closure in geodetic observing techniques and networks and to advocate additions in the GGOS monitoring network and Services where necessary.
Through the projects accepted ongoing Call for Participation Focus Area 3 will progress with the following tasks:
Global Mean Sea Level (middle, vertical scale exaggerated) and some supporting methods
- Identification or (re)-definition of the requirements for a roper understanding of global and regional/local sea level rise and its variability especially in so far as they elate to geodetic monitoring provided by the GGOS Infrastructure, and their current links to external organizations (e.g., GEO, CEOS, and other observing systems).
- Identification of gaps in geodetic observing techniques contributing to sea level research and advocate improvements and additions in the GGOS monitoring network and Services where necessary
- Establishing Focus Area 3 as the interface and point-ofcontact between GGOS and organizations concerned with sea level research aspects
- In the long-term, the aim is to support forecasting of global and regional sea level for the 21st century. Special emphasis will be given to local and regional projects which re relevant to coastal communities, and which depend on the global perspective of GGOS.