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.