Sea Level Monitoring (North and Baltic Sea)

The Federal Agency for Cartography and Geodesy (BKG) publishes two sea-level data products for the North Sea and Baltic Sea, derived from satellite radar altimetry. BKG states that sea-level information is of direct practical importance for infrastructure projects in coastal and offshore areas, especially coastal protection, and that in geodesy the sea level fixes the zero level of the German height system (DHHN2016). Because sea-level rise differs from region to region, the service concentrates on the North and Baltic Seas with regional models and adapted analysis methods.

BKG takes altimeter observations since 1992 from missions including Topex/Poseidon, Jason-1/2/3, ERS-1/2, Envisat, CryoSat-2, SARAL, Sentinel-3A/3B, Sentinel-6A and SWOT, harmonised by the Radar Altimeter Database System (RADS). It adds the FES2022 tide model, regional geoid models and a regional altimeter calibration against the Helgoland and FINO-2 offshore tide gauges.

• Mean Sea Surface Height of North and Baltic Sea (MS-Flaeche): a grid of about 10 km resolution giving the long-term mean sea level at reference epoch 2008.45. One variant, covering the German EEZ, refers to the official German quasigeoid GCG2016, for uses such as planning coastal protection, coastal and offshore surveying and ship navigation; a second, covering the whole North and Baltic Sea, refers to the gravimetric geoid for cross-border scientific use. Absolute accuracy is 4 cm (standard deviation against tide gauges). NetCDF and GeoTIFF.
• Time series of sea surface height (MS-Zeitreihe): 10-day mean sea levels since 1992 for the North Sea, Baltic Sea, German Bight and south-western Baltic, each with a trend estimate. NetCDF and CSV, updated annually.

Both products are free downloads from the BKG Geodatenzentrum under a CC BY 4.0 licence.