Hmax = Maximum wave height occurring in a
record;
T
–
z = Average zero-crossing wave period; the time
obtained by dividing the record length by
the number of downcrossings (or upcrossings)
in the record;
H –
1/n = The average height of the 1/n highest waves
(i.e. if all wave heights measured from the
record are arranged in descending order, the
one-nth part, containing the highest waves,
should be taken and H
–
1/n is then computed as
the average height of this part);
T
–
H1/n = The average period of the 1/n highest waves.
A commonly used value for n is 3:
H –
1/3 = Significant wave height (its value roughly
approximates to visually observed wave
height);
T
–
H1/3 = Significant wave period (approximately
equal to the wave period associated with the
spectral maximum, see Section 1.3.8).