How to determine significant wave height from time series data in Matlab>

Dear all,

I have time series from ocean waves and want to calculate the significant wave height by using Matlab. If you have experience in this topic, could you please to give me matlab script to solve that? Thank you for your helping

Answer 1

[rifat]

I dont know what it means by "significant wave height". But if you are trying to detect the peaks in a time series then try the function mspeaks.

[Peter Mills]

I am also trying to calculate the significant wave height. Significant wave height is the average of the highest one-third (33%) of waves [1]. Does anyone know of a function which will give the heights 1/3 of values from a data series? This might help: [2] https://uk.mathworks.com/matlabcentral/answers/22597-finding-the-position-of-the-1st-2nd-and-3rd-max-value-in-a-matrix

So say we have

WaveHeight=[3 1 5 2 3.1 6 5.5 3 2.5];
We need to find the highest 1/3:
HighestThird=[6 5.5 5]
HS= mean(HighestThird) %significant wave height

This code [2] will give the highest values

[max1, ind1] = max(WaveHeight);
WaveHeight(ind1)      = -Inf;
[max2, ind2] = max(WaveHeight);
WaveHeight(ind2)      = -Inf;
[max3, ind3] = max(WaveHeight);
WaveHeight(ind3)      = -Inf;

But what if we what a function that will calculate the mean of the heights 1/3 of WaveHeight with

length(WaveHeight)

being a variable which may be large?

[1] https://www.weather.gov/key/marine_sigwave

[2] https://uk.mathworks.com/matlabcentral/answers/22597-finding-the-position-of-the-1st-2nd-and-3rd-max-value-in-a-matrix