Sea Level Climate Change Initiative

Sea level is a very sensitive index of climate change and variability. As the ocean warms in response to global warming, sea waters expand and, as a result, sea level rises.When mountain glaciers melt in response to increasing air temperature, sea level rises because more freshwater glacial runoff discharges into the oceans. Similarly, ice mass loss from the ice sheets causes sea-level rise. The increase of freshwater flowing into the oceans reduces its salinity, decreasing its density and affecting ocean circulation patterns that in turn affect sea level and its spatial variability.

In order to achieve this global objective, the specific objectives that the European Space Agency set for this project, focused on the sea level as index of climate variability, are:

  • to involve the climate research community
  • to develop, test and select the best algorithms and standards
  • to assess and collect information on the quality and error characteristics
  • to provide a complete specification of the operational production system.

DGFI-TUM has participated to the project at multiple levels, that span from the orbit determination of the satellites to the sea level measurement in the polar seas, particularly sea-ice covered areas. In the current phase, the attention is shifted towards the coast, where for several years the sea level data were not used due to problems related to the radar signal (for example, intrusion of land in the area illuminated by the satellite) and its corrections.

DGFI-TUM is responsible for the designing and testing of improved signal processing techniques to exploit the radar signal in the coastal zone and to correct the measurements of range (the distance between the satellite and the sea surface) due to the interaction with the ocean waves. We work in collaboration with other European institutions to be able to understand the sea level variability in the areas that mostly affects the life and the economic conditions of our society: the coastal zones.

More information about the project and the collaboration partners can be found on ESA's project website.

Regional mean sea level trends derived from the improved and homogeneous SLCCI altimeter data record (credit: ESA/CLS/CNES/LEGOS).

Selected Publications

Birol F., Léger F., Passaro M., Cazenave A., Niño F., Calafat F.M., Shaw A., Legeais J.-F., Gouzenes Y., Schwatke C., Benveniste J.: The X-TRACK/ALES multi-mission processing system: New advances in altimetry towards the coast. Advances in Space Research, 10.1016/j.asr.2021.01.049, 2021
Cavaleri L., Bertotti L., Ferrarin C., Passaro M., Pezzutto P., Pomaro A.: Synergic use of altimeter and model sea level data in inner and coastal seas. Remote Sensing of Environment, 261, 112500, 10.1016/j.rse.2021.112500, 2021
Benveniste J., Birol F., Calafat F., Cazenave A., Dieng H., Gouzenes Y., Legeais J.F., Léger F., Niño F., Passaro M., Schwatke C., Shaw A. (The Climate Change Initiative Coastal Sea Level Team): Coastal sea level anomalies and associated trends from Jason satellite altimetry over 2002–2018. Nature Scientific Data, 7, 357, 10.1038/s41597-020-00694-w, 2020 (Open Access)
Gouzenes Y., Léger F., Cazenave A., Birol F., Bonnefond P., Passaro M., Nino F., Almar R., Laurain O., Schwatke C., Legeais J.-F., Benveniste J.: Coastal sea level rise at Senetosa (Corsica) during the Jason altimetry missions. Ocean Science, 1165–1182, 10.5194/os-16-1165-2020, 2020 (Open Access)
Marti F., Cazenave A., Birol F., Passaro M., Leger F., Nino F., Almar R. Benveniste J., Legeais J.F.: Altimetry-based sea level trends along the coast of Western Africa. Advances in Space Research, 10.1016/j.asr.2019.05.033, 2019

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