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Fitting bimodal wind data using Weibull mixture in matlab

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Hi, I have wind data that am analyzing and I intially chose Weibull distribution to fit the data. However, from the results, the wind data displays bimodal behaviour hence unimodal weibull distribution is not fitting it well. I intend to use Weibull mixture to get more accurate resukts. How can I constract Weibull mixture in matlab? Down here is a sample of what i get with unimodal weibull distribution. Kindly help anyone who can. I will really appreciate.

Accepted Answer

KSSV on 29 Jul 2022
REad about fitdist
  1 Comment
okoth ochola
okoth ochola on 31 Jul 2022
Thanks KSSV, at least I have some clue, however not obvious. Do you have any other possible suggestions you share kindly

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More Answers (1)

Jeff Miller
Jeff Miller on 30 Jul 2022
Your sample graph is not a probability distribution, Weibull or otherwise. For a probability distribution, the vertical axis always shows some measure of probability or relative frequency--wind speed is not such a measure. Also, for a probability distribution the possible values of the variable are on the horizontal axis (I guess these values would be the possible wind speeds in your case).
Your graph seems to be a plot of average wind speed versus month, but this is not normally called a probability distribution and it isn't obvious why one might try to fit it with a Weibull distribution.
If you want to describe how wind speed varies across months, thinking of the data as a probability distribution is probably not the right way to go.
Jeff Miller
Jeff Miller on 3 Aug 2022
@okoth ochola Sorry if I gave you the wrong impression--I know a lot about probability distributions but nothing about wind measurement. The histogram you posted has an unusual shape (or at least one I do not recognize) so I am not sure how to advise you. Perhaps you can learn a lot from your data even if they do not follow one of the traditional distribution shapes (as is often the case)?
okoth ochola
okoth ochola on 4 Aug 2022
Jeff, I understand. I hope you've not gotten me from a different perspective. Sincerely from my heart I meant well and I was impressed the way you articulated your answers. I really valued your input and I still do. You see am training to be a physicist especially in renewable energy field and so some of the tools (mathematical, statistical and softwares) I use am meeting them for the first time. So I have to learn and understand them as fast as possible before I can use them. That is why I was ready and open for any input from someone who is conversant with the tools. I have no problem in interpretation of my results. Indeed, the sample I gave had a weired behaviour that have never seen, so the most logical conclusion was perhaps the wind speed distribution follows that of mixture distribution models. With all humility, I tend to believe this contextualizes my reaction. Kindly if you have ideas that can save me out in this situation I will highly appreciate. My advisors have insisted I find a suitable model for that site and time is a constarin.

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