More foam stripes

As you might have noticed, I am getting a little obsessed with those foam stripes. Another day, a little more wind, looking up the coast:

And down the coast…

Do you notice the irregularities in the foam stripe in the pictures above? Those are the places where, in much calmer weather, you see the funny waves. I.e. there are steps that disturb the wave pattern and hence the foam stripe.

But remember we saw a foam stripe connecting one going in parallel with the pier to one going parallel to the sea wall? It’s here again:

Its taking a very similar path like it did last time, but this time it joins the one parallel to the sea wall, rather than forming a second stripe parallel to the first one.

And if we continue further down the coast, we see a similar phenomenon (we are now walking towards that edge in the background of the picture below).

Looking back, we see another foam stripe coming from the other edge of the pier, joining the one parallel to the sea wall.

See, this is how they meet at the sea wall?

And, funnily enough, a similar stripe can be seen going through the sailing harbour: Entering it through an opening in the pier and then going across the harbour and out the other end, until it finally joins the stripe at the sea wall.

This stripe finally convinced me: There don’t need to be convergences for the stripes to exist, at least not for those that aren’t running in parallel to the coast. Because I cannot imagine a convergence zone running in such a way through the harbour that is partly sheltered from the wind, has pylons in it, and just has completely different conditions than the open fjord. Or at least the mechanisms forming that convergence zone would have to be very different from those forming the other stripes. So now I am thinking those stripes are just advecting foam from places where it accumulated (in front of the pier) to new places where it accumulates some more.

And finally it just gets stranded on land:

See how nicely the foam stripe is going around the obstacle? :-)

One thought on “More foam stripes

  1. Pingback: Nonlinear effects in shallow water waves | Mirjam S. Glessmer

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