#WaveWatching Insta recap: December 2019

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There was a lot of wave watching going on on my Insta @fascinocean_kiel this last December! Partly because I had decided that I wanted my feed to consist of both my 24 days of kitchen oceanography advent calendar and my usual wave watching content. And once I had started the pattern, I wasn’t going to break it… But here I will only recap the wave watching part, check out the advent calendar on its own page.

December started off with what has become a bit of a pattern recently: wave watching from the train. It’s always surprising to me how much you can actually see from a train window! Below, for example, the reflection of the bridge in the water helps see the prevalent wave lengths.

Next: wave watching on my way to work! My commute is pretty awesome for sight seeing!

Here we see a wake hitting the pier.

In early December, I went to Nuremberg for work. But of course I managed to squeeze in a little wave watching there, too! The river Pegnitz is very much tamed inside the city, which leads to very pretty flow pattern. For example this submerged hydraulic jump below.

Doesn’t it look spooky how the reflection of the houses is deformed where the water shoots down the weir?

And here is a different hydraulic jump. I love the little wakes that show up around the disturbances on the weir!

My friend Nena took this picture of me wave watching in Nuremberg. You bet I will manage to find waves!

And then some more conventional sight seeing…

Getting distracted by drops falling into the Pegnitz… Isn’t it cool how the wave rings are being advected with the current, so that despite the drops all falling on the same spot in space, the wave rings don’t end up concentric?

And some rapids — with hydraulic jumps! — on the Pegnitz.

Back in Kiel!

The different colors in the sky make it very easy to observe pattern in the waves. The sides of the waves that are sloping towards us reflect the bright sky above us, the slopes facing away from us the dark clouds.

Windy day! See the foam that has been blown with the wind and collected at the shore?

We also see the stripes that form when strong winds blow in a consistent manner for a long period of time: Langmuir circulation!

Then, one day, I saw really cool ripple pattern in the sand. At the very top, ripples in the waves. At the very bottom, ripples in the sand. In between, slightly larger breaking waves, and at the top right stripes of darker matter aligning with the waves‘ direction of travel. I wish I knew more about the transition between the light material being sorted into stripes and the the whole sandy sea floor being shaped into ripples. I guess it’s a function of water depth as well as wave length (so how much energy actually reaches the bottom), can anyone explain it?

And I got this comment by @coastalgeology.kiel: “Dear Mirjam, the beautiful ubiquitous regular bedform structures sure are fascinating in their regularity. Note the long symmetric ripple crests that merge and diverge (=bifurcations). This is a nice question about stability: The sea bed moves if it can… And fine sand may form symmetric ripples if the back and forth motion of the waves is strong enough to move, but not too strong to wash away the structures. The wavelength of the ripples scales with the orbital velocity and the period of the waves and the bed sediment characteristics (grain size and roughness). If no sand is available, if it is too coarse, or the bed and wave characterists change, ripples cannot form. In your photo this is the case in the vicinity of the algae, and in the region of shell hash, which is transported (partly in strikes) but does not form ripples itself…”

Next day: Watching swans and their wakes.

And then: back to work. Watching the rain on a puddle…

And I guess the next day I wasn’t feeling like grey Hamburg weather, so I dreamt myself back to sunny Bergen!

Then, more wave watching from the train. Today with a ship’s wake as well as the wake that forms at the bridge’s pylon because there is a strong current on Elbe river.

And then, I went on a trip with my godson & his family to Möhnesee. We’ve been there before (you might remember the very cool hoar frost we saw there), but it’s always worth a trip!

It was a very windy day, so we got to see some nice wave action.

The gusts of wind ran over the surface of the lake, making the weirdest pattern.

Fun to see how in the lee of the land the water surface is absolutely flat, but the further out of the lee you move, the more wave action happens!

Also really interesting to see how little water there is in the reservoir, and how previous water levels are still archived in the stripes of debris on the shore.

And: A foam stripe parallel to the wall!

This is always such an interesting place to visit!

Here the downstream side of the reservoir. Quite impressive!

And then: Some gold fish watching!

I didn’t use any filters or anything on these pictures, the fish were really that colorful! Here with some waves after a pebble happened to drop into the pond…

And some wind waves.

And the super spooky reflection of the dark, naked tree skeletons in the back…

I love how there are so many layers visible here from the reflection at the surface to fish at different depths. This might actually be one of my favourite wave watching pics of all times!

But then I of course always love water running into water, making waves…

Some more layers here: Reflections, surface waves, stuff floating in the water, ripples on the ground…

Oh, and then the one day where I only managed to see the water by proxy of seeing the cranes at the port of Kiel across the city.

But making up for it with my porthole back home, and my Christmas tableware that I found a couple of years ago and that I loooove despite (or because of?) its horrible kitschyness.

But: Back to proper waves!

I love how you can see all these different stages of wave breaking at once: Waves that are still far out don’t seem to have distinct crests, but the closer they get to shore, the more pronounced the crests become. Steeper and steeper, until they finally break and a water-and-foam mixture is pushed up on the sand.

Below, what I find most fascinating is this really smooth-looking stripe parallel to the wave crests, in between the one that is breaking and the one that is about to break. Of course there can’t be wind waves on water that has just been through a wave-break, but still! Fascinating!

Similar thing here.

I also think it’s super cool to watch the foam vanish on the sand. It doesn’t get pulled back into the sea, it just seeps down into the shore.

Looking back at these pictures makes me really happy. Such a great day :-)

Below, you can see the little foam-free circles, where large bubbles just popped.

More wave stages: In the very front the left-over foam, then foam just being pushed on shore, and then a wave juuuust about to break. So cool!

And now properly breaking!

So cool how far the water is being pushed up the beach even after the wake already broke!

It’s just sooooo beautiful!

Meeting up with some scicomm friends! Of course this had to include some wave watching…

What I find super fascinating here is how a sharp gradient in the sea floor makes waves break instantaneously, leaving this turbulent pattern that looks so much like lace!

More wave watching from the train: The bridge’s pylon’s wake!

And water wrapping around a stone in a very cool way.

Rainy Christmas morning.

And: Throwing a pebble into a small stream. See the first splash?

And then the pillar?

And then all the wave rings?

And growing wave rings?

And even larger wave rings?

And a wave riddle for you: Why is there such a bow wave on a ship that is clearly moored?

More port of Hamburg!

And a little wave watching in the dark. See how the reflection of the Christmas tree looks very different depending on how many waves there are on the water’s surface?

More wave watching from the train!

Beautiful wake!

And here we go with my Instagram’s “top 9 of 2019” pictures (according to how many likes they got):

  • two pictures of the port of Hamburg (thanks to my beautiful commute!)
  • two pictures taken from the ferry on my way home after 2019’s Bergen month
  • and a lot of Kiel fjord pics with wave watching, cloud watching, and ship watching!

Funnily enough, a different algorithm (because I was too impatient to wait for the first one I tried) came up with a slightly different selection. Love that seagull!

So here we go, that was my December 2019 wave watching Insta!

#BergenWaveWatching: Gutters and storm drains

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Reposted from Elin’s blog:

Kjersti, Steffi, Elin and myself (Mirjam) recently discussed ways to better integrate the GEOF105 student cruise into the course. My suggestion was to ask the students to observe things throughout the whole duration of the course, and then have them relate their time series with what they observe when “at sea”. In this mini series tagged #BergenWaveWatching, I write up a couple of suggestions I have for observations that are easy and fun to make. I am anticipating that my suggestions will be strongly biased towards #wavewatching, so if you have any other suggestions, I am all ears! :-)

Where to go

Pretty much anywhere you like / need to go to anyway

When to go

When it’s raining

What to look out for

Pattern in puddles, gutters, storm drains. Because there is so much more to them than just being the means of getting rid of water or annoyances where water has accumulated! For example, check out the roll waves in the picture above and my blog post on those.

Or the picture below. What’s going on there? Solution to this wave riddle here.

Waves on a puddle on a street in Bergen. Picture from this blog post.

What to do with the data

Collect, describe, become more aware of what is happening everywhere around you.

How this is relevant for the student cruise

Not directly, it’s about forming the habit of looking at the world through the eyes of someone who’s interested in waves, which can then lead into the habit of looking at the world with a focus on anything you are specifically interested in.

Do you have suggestions for us? What other spots or topics would you recommend in and around Bergen to be added to the #BergenWaveWatching list? Please leave a comment! We are always looking to expand this list!

New #WaveWatching series happening over on Elin’s blog: #BergenWaveWatching!

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Kjersti, Steffi, Elin and I recently discussed ways to better integrate the GEOF105 student cruise into the course. Right now,  even though students write a report about their work on the student cruise, it’s pretty much a one-off event with little connection to what happens before and after, which is a pity. Having a whole research ship for a whole day for a group of 6-8 students (or possibly 10 next year) is such an amazing opportunity! We want to help students make the most of it by attempting to foster a curious mindset before they board the ship.

One idea is to ask the students to observe things throughout the whole duration of the semester, and then have them relate their own “time series” of those observations with what they observe on the student cruise. Ideally, students will be observing their chosen topic for a couple of weeks before the cruise, then go on the cruise looking at everything there with a focus on that topic, and then continue to observe it in their daily lives after the cruise. But even if it’s not connected to the student cruise or this specific class, I think giving students the task to make regular observations over the course of a whole semester would be a really good way to connect their studies better with their regular lives outside of university.

Do I have ideas of what the topics could be? Of course! And I have scheduled posts over the next two months, in which my ideas will be presented one by one. But today, I want to talk about what I think what purpose this assignment would serve.

The goal is not to collect data that will advance science or to work on original research questions. It is rather to help students get into the practice of focussing on details in the world around them that might otherwise go unnoticed. To collect observations using only minimal resources (like for example stopping on their commute for seconds only, taking pictures with their smartphones, using the readily available weather forecast for context). To try and explain pattern they observe using their theoretical background from university. I want to help students get into the habit of actively observing what is going on around them, to become fascinated with discovering things related to their studies in their everyday lives.

I myself, for example, am absolutely fascinated with waves, and I notice them anywhere (read more about that on my blog, if you are interested). On the most recent GEOF105 student cruise, there was a bucket that was used to bring seawater up on the deck for salinity to be measured. And what jumped out on me? The standing waves in that bucket! You see them in the picture below, but what struck me was that most people really didn’t seem to notice what was going on there, and how FASCINATING it was. Someone even commented to the effect that they would have never noticed the waves in the bucket if I hadn’t pointed them out to them, even though they were sticking probes right into the waves. And while I spent the better part of two days moving the bucket around to see all the different wave pattern that occurred on different spots on deck, most other people didn’t even seem curious to find out why myself and a handful of other people were staring into a blue plastic bucket. And that makes me sad. Does everybody need to find waves fascinating? Of course not. But should students at least be a little curious about science topics that clearly fascinate their instructors? Yes, I believe so.

More about the cool waves in the blue bucket in this blog post!

So my mission with this series of blog posts is to give examples of where you can easily observe oceanography-related phenomena in and around Bergen, hoping that you might start looking at those spots with different eyes. And maybe you will find a specific topic that you become fascinated with. Because once you start focussing on something that seems random and rare, the very thing seems to appear everywhere in your daily life. Like for example hydraulic jumps. As shown in the picture below — once you start focussing on those, you see them appear everywhere as if out of thin air.

Hydraulic jumps. Picture from this blog post

This kind of curiosity around physics phenomena is — in my opinion — absolutely desirable, especially in students. It makes dry theory or seemingly obscure topics become more relevant. As you start noticing phenomena, you also start noticing more about them, for example understanding the conditions under which the appear. And you also start anticipating where they might occur, so you will look to see whether your prediction is correct. It’s a vicious circle, but one that I would encourage you — and especially students — to enter. To me, it’s part of my identity as a scientist — to use my initial understanding of processes to continuously want to learn more and more about them.

Wave watching has definitely become a part of my life that I don’t want to miss. What will you start seeing everywhere? Or what is it that you are maybe already seeing everywhere that most people don’t? I am anticipating that my suggestions in this #BergenWaveWatching series will be strongly biased towards #wavewatching, so if you have any other suggestions (maybe even with pictures already?), I would love to hear about them! :-)

…and check out the #BergenWaveWatching series here!

#BergenWaveWatching: Looking at waves from all sides in Lille Lungegårdsvannet

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Reposted from Elin’s blog:

Kjersti, Steffi, Elin and myself (Mirjam) recently discussed ways to better integrate the GEOF105 student cruise into the course. My suggestion was to ask the students to observe things throughout the whole duration of the course, and then have them relate their time series with what they observe when “at sea”. In this mini series tagged #BergenWaveWatching, I write up a couple of suggestions I have for observations that are easy and fun to make. I am anticipating that my suggestions will be strongly biased towards #wavewatching, so if you have any other suggestions, I am all ears! :-)

Today we have another really accessible spot in Bergen that is super well suited for wave watching!

Where to go

Lille Lungegårdsvannet in Bergen city center

When to go

Whenever you happen to walk past there anyway

What to look out for

Suggestion 1: Waves and wind direction. The latter is very easy to observe from the fountain. And Lille Lungegårdsvannet is amazing for wave watching because you can walk all the way around and see waves from all sides!

Looking at Lille Lungegårdsvannet with the wind. Waves only appear at a distance from the shore in the foreground, because the water is sheltered from the wind by the shore. Blog post on this here.

Suggestion 2: wave reflection. Due to the geometric shape of Lille Lungegårdsvannet with all the straight edges all around, wave reflection can lead to really cool pattern! Can you relate what’s going on to the wind direction?

What to do with the data

Depending on how often you go, you can either relate the wave field to the wind direction and strength (both your own estimates and what the weather forecast says about those). Or you can describe a single situation like I did for example here.

Looking across Lille Lungegårdsvannet into the wind. See how the waves are now a lot taller than in the picture above? Blog post on this here.

 

The geometric shape of Lille Lungegårdsvannet leads to pretty reflections! Picture from this post

How this is relevant for the student cruise

Understanding waves is very relevant for anyone being on the water. Whether you are riding off a storm, deploying instrumentation or trying to keep the boat as steady as possible for sensitive work, being able to read the waves is key.

Also, connecting observations of conditions at land and sea to wind speeds is how the Beaufort scale was originally defined. Of course, you won’t see a fully developed wave field on a body of water as small as Lille Lungegårdsvannet, but it’s a good first step to observe differences.

Do you have suggestions for us? What other spots or topics would you recommend in and around Bergen to be added to the #BergenWaveWatching list? Please leave a comment! We are always looking to expand this list!

#BergenWaveWatching: observing waves and tides on Storelungeren

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Reposted from Elin’s blog:

Kjersti, Steffi, Elin and myself (Mirjam) recently discussed ways to better integrate the GEOF105 student cruise into the course. My suggestion was to ask the students to observe things throughout the whole duration of the course, and then have them relate their time series with what they observe when “at sea”. In this mini series tagged #BergenWaveWatching, I write up a couple of suggestions I have for observations that are easy and fun to make. I am anticipating that my suggestions will be strongly biased towards #wavewatching, so if you have any other suggestions, I am all ears! :-)

Really close to home today! Nygårdsbruen.

Where to go

Nygårdsbruen — the bridge right next to GFI

When to go

Whenever you are going to or leaving GFI anyway works fine, especially if that happens to be at around the same time every day

What to look out for

That kind of depends on how regularly you will realistically be able to go there. If you are there several times per week, you could look at the tidal current. Which direction is it going in, how strong is it, what’s the water level like, …?

If you aren’t going as often, maybe focus more on a general description of what is going on. Is there a tidal current visible? Is it going in or out? Does it have an influence on the wave field? What other factors influence the wave field? What’s the wind direction? Can you see areas that are sheltered from the wind and areas where the wave field is more developed? Can you easily look into the water? Where, and where not? Why is that? That kind of stuff.

The current acts as a barrier to wind-generated waves. How cool is that? Blog post on this here.

What to do with the data

By “data”, I mean the collection of pictures on your smartphone. You could, for example, relate them (thanks to the phone’s time stamp on the pictures) to time before/after high water as I did in this post for tides on the Elbe river in Germany. This of course doesn’t account for the spring/neap signal, which you might want to include.

Questions that I find interesting: When is the strongest current actually happening relative to high water, and within the spring/neap cycle? In what way do ingoing and outgoing currents differ (and why? Shape of the landscape? Different gradients in the water level? …)?

Or, if you don’t have a lot of data from different days, describe what you see (maybe similarly to what I did here).

Looking towards Storelungeren. See there are at least four different areas of what you see on the water? (Being able to look into it clearly, being able to look into it where shaded by the bridge, reflection of the other shore, rough surface due to wind waves)

How this is relevant for the student cruise

One task on the GEOF105 student cruise is relating trajectories of drifters to several factors. The wind field on that day, for example, but also the tidal currents in byfjorden. So having a good intuitive understanding of tides makes interpreting the drifters’ trajectories a lot easier, even though the drifters will be deployed in a different area.

More generally, this suggestion is about repeatedly observing a very easily accessible body of water and looking at how it looks different each time. This is good practice of observational skills, and also eye-opening to the many ways in which a body of water can look different at different times — different times in the tidal cycle, different seasons, different weather, especially different winds.

Do you have suggestions for us? What other spots or topics would you recommend in and around Bergen to be added to the #BergenWaveWatching list? Please leave a comment! We are always looking to expand this list!

#BergenWaveWatching: observing the tides from a bus

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Reposted from Elin’s blog:

Kjersti, Steffi, Elin and myself (Mirjam) recently discussed ways to better integrate the GEOF105 student cruise into the course. My suggestion was to ask the students to observe things throughout the whole duration of the course, and then have them relate their time series with what they observe when “at sea”. In this mini series tagged #BergenWaveWatching, I write up a couple of suggestions I have for observations that are easy and fun to make. I am anticipating that my suggestions will be strongly biased towards #wavewatching, so if you have any other suggestions, I am all ears! :-)

My first recommendation in this series is actually more about watching tides than watching waves, but it is impressive and well worth a visit!

Where to go

Straume Bru — either get off the bus 51 at that bus stop and walk around (as I did for this blog post), or, if you have to take that bus regularly anyway, just observe from the bus.

Observing the tidal current at Straume Bru from the bus

When to go

If you are going for a one-off visit, you might be well-advised to look at the tidal forecast and time your visit so you are there a little later than half time between high water and low water (or, I am assuming, low water and high water), so you will be able to observe strong tidal currents. As the currents change direction when the tide turns, there will also be periods with no current or very weak current, which are probably not nearly as impressive. Ideally I would want to spend a full tidal cycle there, but I haven’t gotten around to doing that yet. Maybe you will?

If you only pass the current on the bus, then you will hopefully do it often and take many pictures!

What to look out for

If you are at Straume Bru at the right time, you will be able to see a strong current going underneath the bridge. You might want to take pictures of the current that also include features of either the bridge or other structures or landmarks, so you can relate this and further pictures you might take to each other. What’s the water level like? How strong is the current? Which direction is it going in?

A picture of the tidal current at Straume Bru, including the bridge itself for scale and reference

What to do with the data

By “data”, I mean the collection of pictures on your smartphone. You could, for example, relate them (thanks to the phone’s time stamp on the pictures) to time before/after high water as I did in this post for tides on the Elbe river in Germany. This of course doesn’t account for the spring/neap signal, which you might want to include.

Questions that I find interesting: When is the strongest current actually happening relative to high water, and within the spring/neap cycle? In what way do ingoing and outgoing currents differ (and why? Shape of the landscape? Different gradients in the water level? …)?

How this is relevant for the student cruise

One task on the GEOF105 student cruise is relating trajectories of drifters to several factors. The wind field on that day, for example, but also the tidal currents in Byfjorden. Even though the drifters will be deployed in a different area, having a good intuitive understanding of tides makes interpreting the drifters’ trajectories a lot easier.

Do you have suggestions for us? What other spots or topics would you recommend in and around Bergen to be added to the #BergenWaveWatching list? Please leave a comment! We are always looking to expand this list!

November #WaveWatching: A summary of my daily Instagram

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All throughout November, I’ve posted pretty much daily to my #WaveWatching Insta @fascinocean_kiel.

And here are all the posts for you! If you prefer daily updates, why not follow my Instagram?

But here we go with a month’s worth of wave watching pics. First: a wake reaching the beach. How do we know it’s a wake? Because it is so super regular (and also because I saw the ship it belongs to ;-))

And then: Tiny rip currents!

It was very nice to observe this dangerous phenomenon on a tiny scale.

More rip currents…

And a seagull that flew away before I could get the picture I wanted.

The Oslo ferry changing course and sailing towards the sun… At least for a short moment, before finishing the 180 degree turn and backing up into its berth in Kiel port.

Such a nice criss cross pattern of waves!

And a movie of a criss cross happening in a different spot.

Another criss cross.

Fog in Kiel. I guess it’s November…

More fog.

Another seagull that flew away before I could take the picture I wanted to take.

The Oslo ferry turned and left us with its turbulent wake.

On the train south. This view usually looks a lot nicer with either a fountain or a Christmas tree… Plus there are super pretty street lamps that were taken away for the construction period.

This is the view I know and love… At very low wind conditions.

Slightly more wind… And can you see it’s taken from a train? Wave watching from trains is fun!

And even more wind!

And even more wind!

Oh, and then my sister & her kids & I went to look at the ship lift in Scharnebeck. So awesome! Here we are looking out on the lower part of the canal, the basin with the ship is what looks like the ceiling in the picture below!

When that basin has been lowered all the way (38 meters! Quite impressive, don’t you think?), we can watch the ships sailing out.

Bye bye, ship! Have a safe journey!

Waves in a little well.

Autumn leaves and hydraulic jumps!

Sun set on the train home.
Oh, and a sun rise with a ship sailing backwards. Some days are weird like that…

A seagull watching the Oslo ferry arrive in Kiel. Welcome!

And the Oslo ferry turning.

Pretty sunset on a very windy day!

On the picture below, I commented if people thought those rain curtains would look like Northern Lights if I used the right filters.

And this is what my brother-in-law did. Yep. Northern lights in Kiel! :-)

More sun set in Kiel.

And pretty autumn leaves!

The faucet at a conference center I gave a workshop at.

Part of my Insta-Story that day:

More pics from Kiel.

No idea what caused this very sharp distinction between the two parts of Kiel fjord!
I like this little plant!

Fog again…

But autumn leaves!

The pilot ship and the Oslo ferry.

Very cool discovery that Sara made, check out the blog post I wrote about it.

A small tug and its wake.

And the wake by itself.

Now the wake arrives at the sea wall!

And is being reflected.

Very cool interference pattern, especially with the added waves caused by the irregularities in the sea wall.

Looks so pretty!

I find it super fascinating.

No idea where all those higher order waves come from!

Oh, and my overturning circulation experiment.

And the comparison of rotating and non-rotating thermally driven circulations.

And salt fingering!

And wave watching in the dark.

Aaaand: A trip to the beach!

Always nice to see waves running around obstacles into sheltered areas like here:

And here:

And even though at first I was pretty annoyed that someone was walking through my picture, I think it makes it kinda entertaining. What do you think, did her feet stay dry?

And super cool: The YouTube video that uses my “dead water” experiments went live!

More wave watching

And ships meeting in the dark

And sitting inside with flowers and a nice fire and watching ships.

But then November was pretty grey for many days in a row…

So I worked on my Advent calendar: 24 Days of #KitchenOceanography!

And went more wave watching.

And went to play at GEOMAR with Torge and Rolf Käse!

This is a team picture of a successful Friday evening.

More experiments!

And then it got cold: Frost on leaves on the pier!

And a beautiful sunrise.

Now sunrise with frost in the foreground.

And the third picture that I needed in that row so I could start with the Advent calendar afterwards :-D

And this is the blog post advertising 24 Days of #KitchenOceanography

Documenting the little walk I took to stay sane while trying to finish up the Advent calendar…

And here we go, that was my November on Instagram! I am quite impressed with the sheer volume of pictures I have posted, and that I managed to write semi-useful captions to most (on Instagram, that is, not in this blog post ;-))

Starting tomorrow: 24 Days of #KitchenOceanography

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So I wanted to make a super cool advent calendar for my godson: One kitchen oceanography experiment every single day. But then he ended up falling in love with LEGO Hogwards. So what’s the best godmother in the world to do? Of course I packed 24 parcels of that instead (all nicely building upon each other, of course. Which means I had to build pretty much the whole thing in order to be able to pack it in a sensible way…).

Anyway. I still did the 24 days of #KitchenOceanography, and I will be sharing them, one by one, over the next 24 days, starting tomorrow! And I am super excited about it.

I don’t usually ask for this, but please tell your friends about it, share my posts, send out links. And then please also give me feedback so I can improve it for next year, when my godson will be given this, whether he likes it or not :-) And when I am also planning to publish this on paper, so it’s an actual gift (and it’ll be published so you can get your hands on it, too, if you like!)

Below are the details of how it’s going to work and what kind of equipment we’ll need (everything always both in German and English, as will be all the following 24 days!)

Find the whole story that connects all the experiments here (Links will be added to the experiments as they go live one each day).

Rotating tank experiments on a cone

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I had so much fun playing with rotating tank experiments on a cone this afternoon! And with Torge Martin (who I have the awesome #DryTheory2JuicyReality project with) and Rolf Käse (who got me into tank experiments with an amazing lab course back in 2004, that I still fondly remember). We tried so many different things, that I will at some point have to describe in detail, but for now I just need to share the excitement ;-)

Here, for example, a blue fish-shaped ice cube. This experiment is pretty much the topographic Rossby wave experiment described here, except now we aren’t on an inclined plane, but on a cone. Which is basically an infinitely long inclined plane — the ice cube doesn’t encounter a boundary as it travels west, it just goes round and round the tank until it melts. And look at the cool Rossby waves!

Then we did another one of our favourite experiments, the Hadley cell circulation. What was really fascinating to observe was how turbulence the turbulence that was introduced by dripping dye into the tank changed scales. At first, we had the typical 3D pattern with plumes shooting down. But over time, the pattern became more and more organized, larger, and 2D. See below: The blue dye had been in the tank for a little longer than the red dye, so the structures look completely different. But interesting to keep that in mind when interpreting structures we observe!

Here is another view of the same experiment. Since we are cooling in the middle and rotating very slowly (about 3 rotations per minute), the eddy structures aren’t completely 2D, but they are influenced by an overturning component.

This looks even cooler when done on a cone. Can you see how there is both an overturning component (i.e. the plumes running down the slope) and then still a strong column in the middle?

This just looks so incredibly beautiful!

And one last look on the eddies that develop. We saw that there are cyclonic eddies happening in the center of the tank and anti-cyclonic eddies at the edge. Since we are on a cone, I could imagine that it’s just due to conservation of vorticity. Stuff that develops near the center and moves down the slope needs to spin cyclonically since the columns are being stretched, and on the other hand things that develop near the edge must move up the slope, thus columns being compressed. What do you think? What would be your explanation?

Nansen’s dead water explained on YouTube

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Remember the experiment on Nansen’s observation of “dead water” that Elin & myself set up as part of GEOF213? Our movies of this experiment are now featured in a brilliant Youtube video by my friend, the german science communicator Doktor Wissenschaft! Check it out! (English subtitles available)

I feel so proud to have contributed to such a cool video! :-)

 

P.S.: Doktor Wissenschaft also has an Instagram profile which is totally worth checking out. He posts interesting physics, chemistry and biology facts in twice daily. And occasionally he includes cool ocean and climate facts, supplied by yours truly. If you have fascinating facts that should be featured on Doktor Wissenschaft, please feel free to let me know and I will happily forward them!

One of Doktor Wissenschaft’s facts on Instagram: “If all Antarctic ice did melt, sea level would rise by approximately 58 meters”