Figure 3.

Panel (a) shows n versus E₀, created from clusters of E₀ that each contain about 100 estimated values. Each point on the plot gives the mean of this sample of E₀ values versus the median of the corresponding sample of n values. The transition between n = 1 and n = 0 occurs at E₀∼1.5 m²s. The median of n versus the mean of the frequency calculated as the mean of all the frequency samples corresponding to the E₀ samples in a bin is shown in (b). There is a dependence on frequency which follows closely the dependence on energy because the two are strongly correlated for f > 0.1 Hz in the spectral tail where E₀∝f⁻⁴. (c) The percentage of profiles in each E₀ bin where n = 0, i.e. the waves decay in direct proportion to the distance traversed.