<p>I want to determine the height of a sine wave for some tidal constituents for which I would use the following equation: ()=cos⁡(−), where H is the amplitude,  is the speed of rotation, t is the time elapsed and  is the phase lag. If I have got the following data for a site, how do I determine the phase lag so that I can calculate Y(t).</p>
<p>Constituent M2, Amplitude 3.18, Degrees per hour 28.984, Radians per hour 0.5058, Phase degree 173</p>

CC BY-SA 4.0
2022-11-10T18:58:14.673Z
Worth checking up on... is this a homework question (or where are you getting the data, may be of interest to people, if not)
JeopardyTempest
CC BY-SA 4.0
2022-11-10T18:59:44.760Z
And are you needing to produce the entire time function of height, or just the "height of the sine wave" (which isn't as involved at all)
JeopardyTempest
CC BY-SA 4.0
2022-11-18T15:04:26.440Z
It is from a paper Swansea Bay Tidal Lagoon Annual Energy Estimation by Petley and Aggidis. I was just wanting to work out the height of the sine wave to then use in energy estimates with coding
Claire
CC BY-SA 4.0
2022-11-19T04:58:52.063Z
So more than just the peak height (which is of course the amplitude) I take it!  (Hopefully you can understand why I had a wonder if it was a homework question, many times in undergrad they'd ask questions like that, wanting the max height, and giving a fairly involved trig function, and people would get lost trying to compute it all , when it's right there given by the amplitude).  But sorry, have no more clue than that, upvoted, as it's an interesting looking question
JeopardyTempest
<tides>
How do I determine the phase lag for a tide
Claire
# How do I determine the phase lag for a tide

(Asked by: username_0 on 2022-11-10)

I want to determine the height of a sine wave for some tidal constituents for which I would use the following equation: ()=cos⁡(−), where H is the amplitude, is the speed of rotation, t is the time elapsed and is the phase lag. If I have got the following data for a site, how do I determine the phase lag so that I can calculate Y(t).

Constituent M2, Amplitude 3.18, Degrees per hour 28.984, Radians per hour 0.5058, Phase degree 173

**Tags:** tides

> **Comments:**
> **username_1**: Worth checking up on... is this a homework question (or where are you getting the data, may be of interest to people, if not)  
> **username_1**: And are you needing to produce the entire time function of height, or just the "height of the sine wave" (which isn't as involved at all)  
> **username_0**: It is from a paper Swansea Bay Tidal Lagoon Annual Energy Estimation by Petley and Aggidis. I was just wanting to work out the height of the sine wave to then use in energy estimates with coding  
> **username_1**: So more than just the peak height (which is of course the amplitude) I take it!  (Hopefully you can understand why I had a wonder if it was a homework question, many times in undergrad they'd ask questions like that, wanting the max height, and giving a fairly involved trig function, and people would get lost trying to compute it all , when it's right there given by the amplitude).  But sorry, have no more clue than that, upvoted, as it's an interesting looking question  

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