Wave cycles are pairs of a maximum value and a corresponding minimum value. There are many different methods to select the pairs, and here are a few of them, which can be analysed in the WAT toolbox:

A *trough2crest wave cycle *is the pair of the minimum value in the
interval between a downcrossing and the following upcrossing of a reference
level, and the maximum value in the following interval between the downcrossing
and the next upcrossing.

The *crest front wavelength *is the distance
between the minimum and the maximum.

A *min2Max cycle* is a pair of a local minimum and the following local
maximum.

A *rainflow cycle* is a max/min-pair of a maximum and a certain
minimum. For a local maximum at a level *u* the minimum
is selected as the minimum which is reached when one wants to return above
*u *(in the forward or backward direction) with an as small downward
excursion as possible.
Min/max rainflow
pairs are defined analogoulsy