Expedition learning

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Last week, we ran an “expedition learning” course for 17-year olds. They were separated into several groups, working on different topics, and mine (unsurprisingly) worked on waves. You can see here what kind of stuff we observed when first testing the stretch of coastline we wanted to do our expedition to. And now you’ll get a picture dump of the actual expedition.

We started out in not-so-ideal-but-really-not-too-bad-either kind of weather, as you can read off the tracks below: It had been raining a little, but not very hard, and it had stopped by the time we got there.

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The drift lines looked quite promising.

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My group dove right into it (only figuratively, luckily, not literally). However I wasn’t quite sure if this guy knew what he was getting into?

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At this point we were still very close to the car, so I thought that it might be quite smart strategically to let them figure out here how high the waders go and what happens if the waves are higher than the waders… And the wakes of two ships  meeting up at a headland are a very good place to learn about that kind of things!

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This headland is a very good place to start observing waves in any case. Especially at the typical wind direction found here. Because then, looking back from the light house to the land, you see a large area that is sheltered where waves only build up gradually. Which is a very nice contrast to the waves arriving upwind and makes it very easy to observe differences.

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And then if you look downwind from the headland, you see waves sneaking around the headland from both sides. Those coming from the right are from the fully developed wave field that has been growing all the way down Kiel fjord, and then those coming in from the left are the ones that only started growing downwind of the little barrier shown in the picture above.

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Can you see it? Maybe easier on a panorama kind of picture?

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Of course we always like to look at the ring waves that appear when other waves hit stones…

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I didn’t foresee that wave watching would happen mostly from within the water, but the guys in my group made a good case for walking on the sand bank to actually measure the wave hight depending on the water depth (rather than just observing and estimating from dry land, as I would have done), but why not?

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Luckily, they found the shallowest part of the sand bank in exactly the same spot I would have told them to look for it based on the wave field ;-)

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Btw, a nice example of coastal dynamics right below. We had a coastal dynamics group, too, but I don’t even know if they looked at this kind of stuff, I mainly saw them taking soil samples.

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And I know I made the same observation in the same spot last time, too, but I think it’s fascinating how the different directions of the ripples and drift lines and waves all come together.

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In any case, a nice day at the beach!

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Well, most of the time anyway.

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Luckily, we found shelter!

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Those, btw, are Annika and Jeannine, who were working with a different group on coastal vegetation.

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But: New and interesting pattern on the beach once the rain was done!

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The kids spent the next two days putting all their observations on maps and preparing a presentation, and I am really happy with how it turned out. Of course there is some room for improvement still, but how boring would it be if there wasn’t? ;-) All in all I think it was a pretty successful course!

Traces in the sand

Yes, I am really that fascinated by sand that this is the second post in a week about it.

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And I still think the picture below looks like the place in Qumran where the Dead Sea Scrolls were found!

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Wind field

Another boundary layer experience last week: On my way from work I stopped to take pictures of flags that were outside my university’s main building and that very nicely visualised the wind field (as flags tend to do).

If you just look at the flags, they look weird — they wind field was clearly not changing over time, yet the flags were at a weird angle to each other.

And in the next picture you see why: Because the air had to flow around an obstacle, so stream lines were bunching up.

The next morning, I went past there again and stopped to take more pictures, when a colleague of mine stopped next to me, looking a little puzzled that I was taking pictures of our not especially nice main building.

I explained what I was doing, and we got talking about how you see the world with completely new eyes once you have noticed, or have been shown, something tiny. Isn’t that exciting? :-)

Shelter from the storm

Shelter from the storm, no, shelter from the breeze.

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But we clearly see the sheltering effect of that boat shed on the wind waves… Same thing below. And wasn’t that a beautiful day :-)

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Wind waves

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.

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This kind of stuff is so cool to watch! :-)

More wave-spotting in “urban environments”

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.

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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?

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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

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Walking around a lake to look at waves from all sides

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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.

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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.

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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.

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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!

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Lille Lungegårdsvannet in Bergen

 

 

Weird algae stripes

The other day I was waiting for my friend and her daughter and noticed a weird stripe-y pattern in the distribution of algae. As I kept watching, the pattern started to change.IMG_1787At first I thought that maybe the algae were collecting in nodes of standing waves that were reflected from the sea wall (ok, lake wall) I was sitting on, but this really does not fit with how the pattern developed later, and I have no clue what was going on.

Watch the movie and tell me what you think, please?

Seriously, though. What is going on? I don’t think the pattern is formed by advective processes – you see bubbles and the occasional leave and they don’t move a lot. I noticed that whenever the wind changed, the pattern in the algae also changed, but I didn’t notice a clear rule. And the wave theory only works for the waves coming in in parallel to the wall, I think. Any ideas?