In fluid dynamics, the wave height of a surface wave is the difference between the elevations of a crest and a neighboring 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, including wind sea and swell. 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.
Depending on context, wave height may be defined in different ways:
In physical oceanography, the significant wave height (SWH, HTSGW[3] or Hs) is defined traditionally as the mean wave height (trough to crest) of the highest third of the waves (H1/3). It is usually defined as four times the standard deviation of the surface elevation – or equivalently as four times the square root of the zeroth-order moment (area) of the wave spectrum.[4] The symbol Hm0 is usually used for that latter definition. The significant wave height (Hs) may thus refer to Hm0 or H1/3; the difference in magnitude between the two definitions is only a few percent.
SWH is used to characterize sea state, including winds and swell.Another wave-height statistic in common usage is the root-mean-square (or RMS) wave height Hrms, defined as:[2]