Some throwback Friday evening wave watching (at the locks at Kiel Holtenau with my friend Sara for a nice and relaxing end of the week) to start the new week. The best!
First: The pilot boat going towards the locks. Unusually visible wake — they are going fast today! Plus an interesting sheltering of waves: The wind is coming towards us so outside of those floating pontoons are a lot larger than the ones on this side that haven’t had enough fetch to build up.
Below we see the same wake: But do you see how it’s just ending on the left? That’s because the pilot boat went in behind the jetty on the far side of the fjord, and it’s only these bits of the wake that were able to propagate outside before the boat went in and the waves don’t make it out of the small channel created by the jetty.
And below the pilot boat going out again in a curve: Love how you see the turbulent wake as well as the deformed V-shaped feathery wake. When you look from the pilot boat down on the picture, do you see the individual “feathers” of the V? Love this perspective on wakes!
And this is what you will see of me when you meet me for a coffee anywhere near water. Sorry Sara, but thanks for the picture! :-)
I just found this picture that I took back in May near my friend Elin’s cabin on an island in western Norway, and it’s a really nice illustration of how the same wind will cause very different waves depending on whether it’s blowing over the sea for many kilometres, or over a puddle for only a couple of centimetres.
In July I will be involved in teaching an “expedition learning” course for a week. It will be all about coastal protection in the Kiel region, so two colleagues and I went on a private expedition to scout out what can be explored where. This is a very picture-heavy post, be warned! It’s more a note-to-self to document the different beaches we looked at than something I expect anyone else to be interested in.
We started out in Friedrichsort, where there were nice breaking waves to be observed. My part of the course, you might have guessed it, will be on observing waves…
In Friedrichsort there is a lighthouse on a small headland, and there are sand banks around it that make for very interesting wave fields, like for example below, where the sand bank almost seems to filter out some wavelengths.
Looking seaward over the sandbank, we see breaking waves over the shallow part, and waves being bent around the sand bank.
A similar thing could be seen on a tiny headland: Can you see how one and the same wave crest gets wrapped around the headland?
See? So cool!
Btw, you might have noticed the weather changing a lot over the last couple of pictures. It’s April, I guess… But a couple of raindrops here and there make nice tracers for the time since the last wave washing up over the beach ;-)
Always fascinating: When you can see wave-less spots that are shielded from the wind, and then local wind waves and others that are travelling in from further away. And breaking on a sand bank…
Also, did you see how nice the weather was for a couple of minutes every now and then? ;-)
And here is a close-up of the waves breaking on the sand bank.
Oh, and looking back to where we came from: That’s the lighthouse on it’s headland right there! And my two colleagues figuring out what’s wrong with the GPS they brought. Their part of the course will focus on more geological things than mine…
But I really like this view!
See how nice and regular the waves are that reach the beach even though the local wind field is really messy (as you see a little further offshore) and the waves have gone over the sandbank?
Oh, and always one of my favourites: When nice and regular waves hit a stone and it sends off wave rings. Love it!
One more, because it’s so nice!
And here waves bending around a wave breaker thingy.
And this is a picture that really nicely shows how if you don’t have wind, you don’t have waves. The lagoon there is sheltered so well that you can actually see the reflection of the bird sitting on the edge!
And here we have a very nice superposition of waves coming from different directions and with different wavelengths.
And waves coming through the “slit” between sandbanks and spreading as segments of a circle. Nice!
Oh, and more waves breaking on the sand bank.
After a while, we reached Falckenstein:
Not so far away from where we started out at that lighthouse over there:
Another interesting superposition of wave fields.
Oh, did I mention we did a lot of walking in the sand? About 20k steps. Well, I guess that isn’t even too bad…
Below I really liked the criss-crossing of waves. It’s actually one wave crest crossing itself after being bend by the shallowing water.
And those waves get deformed a lot, too!
And here we knew that it was a matter of minutes until those rain showers would be where we were…
Luckily, this shower went over quickly, too.
And this is the kind of stuff the other courses will be dealing with: Awesome formations in the coast!
Ha, another weather front:
And this is my favourite geological feature: there are interesting features in the sand/soil/stone (however you call it?) and then erosion marks, clearly made by water, right below!
A little bit further along the coast, there are weird wave breakers and if the wind hadn’t died down, we would probably have been able to see more interesting waves than these…
But the waves below were really cool: There were the ones that you clearly see on the picture at an angle to the coast, and then there were waves that came in perpendicular to the coast (so the wave crests were parallel to the coast) and they washed the other waves on the beach and back into the sea. I should really upload the movie…
So those waves above caused ripples in the sand which are parallel to the water line, even though in the pictures the other wave field is a lot more visible!
We ended up in Schilksee and had a look around the marina. Apart from the typical wind / no wind resulting in waves / no waves, we saw……
…this! Pretty cool, huh?
One last look at the coast near Bülk.
At this point, only one of us still felt like exploring every nook and cranny…
Even though there were some pretty nice wave fields, but we could see them from our vantage point without doing an extra step ;-)
Actually, there were a couple of cool features on the beach still. What’s up with those little bays?!
We ended the day with trying this very cool contraption to measure the coast with. It was actually a lot of fun!
And you wouldn’t believe how much work it was to hold that ruler thingy in the wind!
So yeah, that’s what we did. And how was your day in the office? :-)
No matter how often I’ve seen it, I still find it absolutely fascinating how the tiniest structures can have a really visible effect on the downwind wave field. Like for example that pier below, leading to the little hut at the end. There is probably a meter and a half between the water surface and the gangway, which is propped up on really thin pylons. Yet, you clearly see that there are visibly fewer waves downwind of the structure. And the hut itself shades a huge area from wind.
One of my favourite topics right now: Learning to “see” ocean physics wherever you go. For example here: A visit to my goddaughter in Schleswig, and this time we are practicing all she and her mom read about in MY BOOK (and if you have good ideas for a title for that book, please let me know!). So today I’m showing you pictures of phenomena similar to those in my book, but discovered on this recent visit.
For example diffraction when waves pass this pier:
In the image below, I’m showing what I mean: Waves coming in from the right have straight crests (red). As they pass the pier, they get diffracted and bent around (green).
In this spot, this phenomenon can be seen on most days. I wrote about it before, but I have more pictures from previous visits, where the same thing happens in the opposite direction, too: Waves propagating in from the left and being bent around the pier to the right.
Or we can see other wave crests, meeting a rock that breaks the water’s surface.
Those waves (shown in red in the image below) get reflected from the rock, and circular waves radiate away from the rock (green).
A similar thing can also be observed from a flag moored out in the water:
This time, incoming waves are green and the circular waves radiating off the flag are red.
Here we have the red wave crests coming in, and the green reflections.
If we look at it from a little more distance, we can also see another phenomenon: The wave crests are refracted towards the shallower shore:
Again the red crests are the original, incoming ones, and the green ones are the reflection:
And then finally, let’s look at duckies again. And on waves being created by wind:
Below you see the direction of the wind (white): One side of this little channel is shaded from the wind, so hardly any ripples there. But then on the other side, we clearly see ripples and small waves. And we see the wake the ducky made!
And one last picture: Which direction does this little channel flow in?
Yep. From the left to the right!
If you enjoy discovering this kind of stuff on your walks, or know someone who enjoys it, or want someone to learn to enjoy it, you might want to consider checking out my book. In my book, I show many pictures like those above, but I actually explain what is shown in the pictures rather than assuming (like I do on this blog) that my readers are oceanographers anyway… :-)
I recently started looking at waves in “urban environments” (in contrast to “on the sea”) with a new found fascination. The reason why will be revealed soon, but for now just know that there are more waves coming up on this blog!
Today, let’s start by looking at more waves on Store Lungegårdsvannet, like we did before.
Here, you look downwind and see the flat water right in front of you, shaded from the wind by the walls around the lake. And then the further away you look, the larger the waves grow.
Another very funny picture of a similar situation below: See how parts of the lake’s surface reflect the buildings and mountains and clouds really well (since that part of the surface is really flat), whereas other parts are way too choppy and appear a lot greyer on the picture?
Yes, I admit, the purpose of this blog post was not so much to talk about waves as to show you how beautiful Bergen is in May. I miss this city… And my AMAZING Bergen friends!!! <3
The most awesome thing about being on vacation is that I have the time to stare at water as much as I like.
For example the other day, I walked around Lille Lungegårdsvannet on a windy day.
Looking downwind, one sees a very smooth surface right in front of us, and then waves start developing further away. Looking at the fountain, you see that it is actually pretty windy.
Lille Lungegårdsvannet in Bergen
Walking a quarter of the way around the lake, we now look at the fountain at a 90 degree angle to the wind: it is blown over to the right. We now see wave crests traveling and see the shape of the waves much more clearly.
Lille Lungegårdsvannet in Bergen
Walking further, we see the waves coming directly towards us; the fountain is also blown in our direction. All of a sudden the water looks a lot more rough. And of course it feels a lot more windy, too, when the wind is coming right towards us and not in our back.
Lille Lungegårdsvannet in Bergen
And bonus picture: A rainbow in the fountain when we’ve gone 3/4 of the way around the lake. Beautiful day in a beautiful city!
Sometimes you need to look at the bigger picture to understand what is going on, especially when looking at phenomena on the water.
My dad recently sent me the images below from Schleswig: Weird foamy stripes on the water.
They don’t really make a lot of sense until you look at it from a different angle:
Now you see how the foam is forming in the waves all over, but that only some of that foam makes it through the gaps in that floating pier, forming a stripe behind every single gap. Cool, isn’t it?
What I found also really interesting in one of the pictures was this:
The different wave fields upwind and downwind from the pontoons. On the upwind side (right side of the picture above), you see really choppy water. On the downwind side, though, close to the pontoons, the water is pretty calm, and only with increasing distance from the pontoons waves start to build again. And we can see that the waves at the far left of that picture are still a lot smaller than those coming in on the right side, just right of the pontoons!