MSL) - Average height of the sea for all stages of the tide, usually determined from hourly height observations over a 19-year period on an open coast or in adjacent waters having free access to the sea. See National Geodetic Vertical Datum.
The average level between the high and low tide over a year at a given point.
" Niveau moyen de la mer" MSL The mean of the water surface elevation observed over the duration of " Tide periodicity".
the midway point between average low water and average high water in sea level position.In the past, main sea level was used to describe heights.In the United States, the National Geodetic Vertical Datum (NGVD) is now used as a standard height measurement.
A datum, or "plane of zero elevation," established by averaging all stages of oceanic tides over a 19-year tidal cycle or "epoch." This plane is corrected for curvature of the earth and is the standard reference for elevations on the earth's surface. The correct term for mean sea level is the National Geodetic Vertical Datum (NGVD).
(Abbreviated MSL) The average height of the sea surface, based upon hourly observations of tide height on the open coast or in adjacent waters, which have free access to the sea. These observations are to have been made over a considerable period of time.
The value obtained at a site by averaging hourly tide heights observed over a long period of time (preferably 18.6 years). It is also the average water level that would exist in the absence of tides.
Mean plain at which the tide oscillates the average height of the sea for all stages of the tide. At any particular place, it is derived by averaging the hourly tide heights over a 19 years period.
A point of reference to measure lake elevation. It refers to the elevation of the ocean halfway between high and low tide. Lake elevations are measured in feet above mean sea level.
The mean value of sea level extracted from a suitably long series of data (e.g. a month).
A level midway between mean high and mean low tides in an open sea.
Tidal datum that is the arithmetic mean of the hourly water elevations observed over a specific 19-year Metonic cycle (National Tidal Datum Epoch). Shorter series are specified in the name; that is, monthly mean sea level and yearly mean sea level. See: datum
The mean plane about which the tide oscillates; the average height of the sea for all stages of the tide.
The average level of the ocean's surface, as measured by the level halfway between mean high and low tide. Used as a standard in determining land elevation or sea depths.
(abbreviated MSL; or sea level datum). The mean surface water level determined by averaging heights at all stages of the tide over a 19-year period. Mean sea level is usually determined from hourly height readings measured from a fixed predetermined reference level ( chart datum).
the height of the sea surface midway between its average high and low water positions
The mean surface water level determined by averaging heights at all stages of the tide over (traditionally) a 19-year period. Mean sea level is not an equipotential surface ( i.e., not the geoid).
A tidal datum. The arithmetic mean of hourly water level heights observed. visual
(MSL) (1) The average sea surface level for all stages of the tide over a 19-year period, usually determined from the hourly heights observed above a fixed reference level. (2) In aerology, the reference surface for all altitudes. (3) In aviation, the level above which altitude is measured by a pressure altimeter.
The average elevation of the sea over a 19 year period.
The average height of the surface of the sea for all stages of tide.
The average height of the sea surface water level. For the United States, it is computed by averaging the levels of all tide stages over a nineteen year period, determined from hourly height readings measured from a fix, predetermined reference level. It is used as a basis for determining elevations, as the reference for all altitudes in upper air measurements, and as the level above which altitude is measured by a pressure altimeter for aviation. Often referred to as MSL. Related term: sea level
A local datum based on repeated measurements of sea level throughout all of its normal cycles, such as tides and seasonal change. The basis for elevations on a map.