Calculate wave statistics using zero-crossing method

Source: R/waveStatsZC.R

Calculate ocean wave summary statistics, including significant wave height and period.

waveStatsZC(data, Fs, threshold = NULL, plot = FALSE)

Arguments

data

A numeric vector of water surface height data. The data do not need to be detrended prior to use. Typical units = meters
Fs

Sampling frequency of the data, in Hz.
threshold

The minimum height necessary for a zero-crossing event to be considered a wave.
plot

Set to TRUE if summary histograms of wave heights and wave periods are desired.

Value

A list object containing summary statistic values.

  • Hsig Mean of the highest 1/3 of waves in the data set. Units = same as input surface heights.

  • Hmean Overall mean wave height, for all waves (bigger than threshold).

  • H10 Mean height of the upper 10% of all waves.

  • Hmax Maximum wave height in the input data.

  • Tmean Mean period of all waves (bigger than threshold). Units = seconds.

  • Tsig Mean period of Hsig (highest 1/3 of waves).

Details

Based on an upward zero-crossing algorithm originally provided by Urs Neumeier, v1.06. However, by default the algorithm is run as a downward zero-crossing process by inverting the data.

References

Original MATLAB function by Urs Neumeier: http://neumeier.perso.ch/matlab/waves.html

See also

waveStatsSP for wave statistics determined using spectral analysis methods.

Examples

data(wavedata)
waveStatsZC(data = wavedata$swDepth.m, Fs = 4, plot = TRUE)
#> $Hsig
#> [1] 0.3870003
#> 
#> $Hmean
#> [1] 0.2530191
#> 
#> $H10
#> [1] 0.4686878
#> 
#> $Hmax
#> [1] 0.565325
#> 
#> $Tmean
#> [1] 9.622973
#> 
#> $Tsig
#> [1] 11.81855
#>