There are currently 18 terms in this directory beginning with the letter M.
Mangrove Forest
A community of salt-tolerant trees and shrubs, with many other associated organisms, that grows on some tropical and sub-tropical coasts in a zone roughly coinciding with the intertidal zone.
Marker, reference
A mark of permanent character close to a survey station, to which it is related by an accurately measured distance and azimuth (or bearing).
Marker, survey
An object placed at the site of a station to identify the surveyed location of that station.
Marsh
A track of soft wet land, usually vegetated by reeds, grasses and occasionally small shrubs.
+ Soft, wet area periodically or continuously flooded to a shollow depth, usually characterised by a particular subclass of grasses, cattails and other low plants.
+ Soft, wet area periodically or continuously flooded to a shollow depth, usually characterised by a particular subclass of grasses, cattails and other low plants.
Mean High Water (MHW)
The average height of the high water over a 19-year period. For shorter periods of observations, corrections are applied to eliminate known variations and reduce the results to the equivalent of a mean 19-year value. All high water heights are included in the average where the type of tide is either semi-diurnal or mixed.
Mean Low Water (MLW)
The average height of the low water over a 19-year period. For shorter periods of observations, corrections are applied to eliminate known variations and reduce the results to the equivalent of a mean 19-year value. All low water heights are included in the average where the type of tide is either semi-diurnal or mixed.
Mean Sea Level (MSL)
The average height of the surface of the sea for all stages of the tide over a 19-year period, usually determined from hourly height readings. Not necessarily equal to mean tide level. It is also the average water level that would exist in the absence of tides.
Mean Tide Level
A plane midway between mean high water and mean low water. Not necessarily equal to mean sea level. Also referred to as half-tide level.
Mean Wave Height
The mean of all individual waves in an observation interval of approximately half an hour.