Modernisation of the tide gauge at Marseille in the RONIM network
From 7 to 9 April 2009, personnel from the University of La Rochelle (ULR), from the French National Institute of Geography (IGN) and from the Naval Oceanography and Hydrography Department (SHOM) went to Marseille in order to modernise the digital tide gauge which had been in position since June 1998.
The building, situated on the coast road at Marseille in Calvo bay, which houses the original mechanical tide gauge (still working) and the current digital tide gauge, was built in 1883. It is famous because the measurements taken there made it possible to determine the standard zero level for France (NGF) by adopting the average level observed at this spot between 3 February 1885and 31 December 1896. The new equipment was the subject of an agreement between SHOM and the IGN and is included in SHOM's RONIM network of tide gauges.
Radar telemetry has now replaced the ultrasonics telemetry. This instrument measures the sea level every ten minutes and transmits the data, by remote interrogation, to SHOM. A real-time output from the data acquisition unit now makes it possible also to transmit the data in real time. These are visible on the Internet (http://www.ioc-sealevelmonitoring.org/)
Finally, remember that this site forms part of the worldwide GLOSS programme for observing sea levels and has a series of data covering more than a century of variations in sea level (below are the annual means available on PSMSL).