Solstices
Maximum declination of celestial bodies.
SONEL
Système d'observation des variations du niveau de la mer à long terme (Long-term sea level variation observation).
SPC-GD
Service de prévision des crues - Grand Delta (Flood forecasting service – Grand Delta).
SPC-LA
Service de prévision des crues – Littoral Atlantique (Flood forecasting service – Atlantic coast).
SPC-SACN
Service de prévision des crues - Seine Aval - Côtiers Normands (Flood forecasting service – Downstream Seine and Norman coasts).
SPC-VCB
Service de prévision des crues - Vilaine-Côtiers Bretons (Flood forecasting service – Vilaine and Breton coasts)
Spectral analysis
location in the frequency scale of the signals relating to the temporal variations of an observed magnitude.
Spectrum
Graphic representation of the spectral component moduli.
Spring tide
Maximum tidal range.
Stand
Time interval during which the sea level remains practically stationary. Depending on the case we talk about low water stand and high water stand.
Swell
Agitation of the surface of the water, with a regular crest that propagates roughly in the same direction as the others. When a perfect frequency is achieved, we talk of swell, swell being a series of identical, regular waves. In the absence of any clear organization, we talk of a choppy sea.
Synodic revolution
Also known as the lunar month, it is the time interval between two full Moons and two new Moons.
Syzygy
Moment at which the meridian planes of the Moon and the Sun are aligned. It corresponds to the Full Moon or the New Moon.
TAAF
French Southern and Antarctic Territories.
Tidal bore
Wave accompanying the flood stream, observed in certain estuaries.
Tidal current
Horizontal component of the gravitational action of the Moon and the Sun.
Tidal observatory
Tidal observation site including the recording device, called a marigraph, the tidal scale and the levelling benchmarks placed nearby.
Tidal scale
Graduated scale used to read off the height of the tide directly with respect to the "scale datum", preferably located on the hydrographic datum.
Tide
Periodic movement of the sea level due to the effects of the gravitational action of the Moon and the Sun.
Tide curve
Graphic representation of the variations in the height of water.