SONEL aims to develop in a reasonable and rational manner activities carried out in the field of ‘in situ’ observations of coastal sea level using tide gauges; the exchange of know-how and results; the conservation of historic observations; the scientific exploitation of observations made by organisations which do not always have this vocation.
The motivation of SONEL is to get more from several mono-thematic permanent observing networks, either geodetic or sea-level oriented. This will come from integrating them into an efficient data collection and dissemination scheme, and by combining their measurements in order to provide specific products. This synergy is indeed the only way to get a clear and unambiguous picture of what is actually going on at a specific coastal site: is the sea level rising or is the land sinking over long term time scales?
The ancillary tide gauge or geodetic information frequently requested by users to obtain the expected final results is either unavailable or is obtained by unreliable methods. This stresses the importance of an integrated sea level monitoring system like SONEL. Consequently, SONEL aims to be : (i) an integrated sea level monitoring system (different types of data, sources, time and space scales); (ii) a sea level information system handling the data measured by different observation networks; (iii) a national component of international sea level observing systems (e.g., GLOSS); (iv) a national interface for related European and Global projects and databases (PSMSL, TIGA, etc.); and (v) a service based on long term commitment as most sea level studies on climate change require time series spanning a long period of time.