- sea level
the horizontal plane or level corresponding to the surface of the sea at mean level between high and low tide.[1800-10]
* * *Position of the air-sea boundary, to which all terrestrial elevations and submarine depths are referred.The sea level at any location changes constantly with changes in tides, atmospheric pressure, and wind conditions. Longer-term changes are influenced by changes in the Earth's climates. Consequently, the level is better defined as mean sea level, the height of the sea surface averaged over all stages of the tide over a long period of time.
* * *position of the air-sea interface, to which all terrestrial elevations and submarine depths are referred. The sea level constantly changes at every locality with the changes in tides, atmospheric pressure, and wind conditions. Longer-term changes in sea level are influenced by the Earth's changing climates. Consequently, the level is better defined as mean sea level, the height of the sea surface averaged over all stages of the tide over a long period of time.Global mean sea level rose at an average rate of about 1.2 mm (0.05 inch) per year over much of the 20th century, with shorter terms during which the rise was significantly faster (5.5 mm [0.2 inches] per year during the period from 1946 to 1956). This variable rise has been shown to have occurred for a very long time. The sea level appears to have been very close to its present position 35,000 years ago. It dropped 130 m (426 feet) or more during the interval from 30,000 to 15,000 years ago and has been rising ever since. Fluctuations of equivalent magnitude probably have accompanied the alternate growth and melting of continental glaciers during the Pleistocene Epoch (from 1,600,000 to 10,000 years ago) because the ocean's waters are the ultimate source of glacial ice. Slower changes in the shapes and sizes of the ocean basins have less effect.
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sea level — sea .level n [U] the average height of the sea, used as a standard for measuring other heights and depths, such as the height of a mountain above/below sea level ▪ 1000m above sea level ▪ changes in sea level … Dictionary of contemporary English
Sea level — Sea lev el The level of the surface of the sea; any surface on the same level with the sea. [1913 Webster] … The Collaborative International Dictionary of English
sea level — sea ,level noun uncount the average level of the ocean in relation to the land. The heights of parts of the land are measured from sea level: more than 2,000 feet above sea level … Usage of the words and phrases in modern English
sea level — n. the level of the surface of the sea, esp. the mean level between high and low tide: used as a standard in measuring heights and depths … English World dictionary
sea level — ► NOUN ▪ the level of the sea s surface, used in reckoning the height of geographical features and as a barometric standard … English terms dictionary
Sea level — For the sea level change associated with the current episode of global warming, see current sea level rise. For other uses, see Sea level (disambiguation). This marker indicating the sea level is placed on the path from Jerusalem to the Dead Sea … Wikipedia
sea level — noun level of the ocean s surface (especially that halfway between mean high and low tide); used as a standard in reckoning land elevation or sea depth • Hypernyms: ↑water level * * * noun [noncount] : the average height of the sea s surface ◇… … Useful english dictionary
sea level — also sea level N UNCOUNT Sea level is the average level of the sea with respect to the land. The height of mountains or other areas is calculated in relation to sea level. The stadium was 2275 metres above sea level... The whole place is at sea… … English dictionary
sea level — The level of the sea, which serves as the datum used for measurement of land elevations and ocean depths. Sea levels vary greatly from one location to another. Locally, the levels of the surface of the world’s oceans are disturbed by wind driven… … Aviation dictionary
sea level — UK / US noun [uncountable] the average level of the sea in relation to the land. The heights of parts of the land are measured from sea level more than 2,000 metres above sea level … English dictionary