Mean ocean surface
Surface of the oceans determined by space altimetry.
Mean Sun
Fictitious celestial body having the same apparent period of revolution as the true Sun, but with uniform motion. The mean time varies by 0 to 24 hours from the passage of the mean Sun through the upper meridian.
Mean time
Uniform time scale defined by the mean Sun. By definition, a mean time day is 24 hours in length.
MEDDTL
Ministère de l'écologie, du développement durable, des transports et du logement (Ministry for ecology, sustainable development, transport and housing)
Meridian plane
Plane containing the polar axis.
Meshing
Subdivision of an area into simple geometric elements with a view to carrying out mathematical modelling.
MESR
Ministère de l'enseignement supérieur et de la recherche (Ministry for higher education and research).
MIOMCTI
Ministère de l'intérieur, de l'outre-mer, des collectivités territoriales et de l'immigration (Ministry of the interior, overseas territories, territorial communities and immigration).
Mixed tide
Sometimes two high waters and two low waters per day, at other times one high water and one low water per day; the diurnal components are dominant.
Nadir
Point on the celestial sphere directly beneath the observer; opposite of zenith.
Neap tide
Minimum tidal range.
NOAA
National Oceanic and Atmospheric Administration.
Nodal correction
Correction to be applied to the harmonic constants to take into account the variations in the elements of the lunar orbit.
Noise
Component of the magnitude observed inaccessible to harmonic analysis.
NOOS
North West european shelf Operational Oceanographic System.
NTC
National Tidal Center.
NUNIEAU
Digitization of water levels.
Observatory
Organization established in order to study phenomena, events, humans and their activities and elicit remarks and reflections concerning them.
OCA
Observatoire de la Côte d'Azur (Observatory of the Côte d'Azur)
OELR
Office de l'eau de La Réunion (Water office of La Reunion)