Wave height

Merchant ship labouring in heavy seas as a huge wave looms astern

In fluid dynamics, the wave height of a surface wave is the difference between the elevations of a crest and a neighbouring trough.[1] Wave height is a term used by mariners, as well as in coastal, ocean and naval engineering.

At sea, the term significant wave height is used as a means to introduce a well-defined and standardized statistic to denote the characteristic height of the random waves in a sea state. It is defined in such a way that it more–or–less corresponds to what a mariner observes when estimating visually the average wave height.

Several definitions for different situations

Wave characteristics.
with cp the phase speed (or propagation speed) of the wave. The sine wave is a specific case of a periodic wave.
with Hm the individual wave heights, sorted in such a way that the highest wave has m=1 and the lowest wave is for m=N. Only the highest one-third is used, since this corresponds best with visual observations of experienced mariners: eyes and brain apparently focus on the higher waves seen.[2]
where m0, the zeroth-moment of the variance spectrum, is obtained by integration of the variance spectrum. In case of a measurement, the standard deviation ση is the easiest and most accurate statistic to be used.
with Hm again denoting the individual wave heights in a certain time series.

See also



  • Holthuijsen, Leo H. (2007), Waves in Oceanic and Coastal Waters, Cambridge University Press, ISBN 0-521-86028-8 , 387 pages.
  • Kinsman, Blair (1984), Wind waves: their generation and propagation on the ocean surface, Dover Publications, ISBN 0-486-49511-6 , 704 pages.
  • Phillips, Owen M. (1977), The dynamics of the upper ocean (2nd ed.), Cambridge University Press, ISBN 0-521-29801-6 , viii & 336 pages.
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