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The mystery of Lokksund. Mysterious as ever, and I am still intrigued…

Forget climate change and all the big questions, there is this one thing that is really bugging me because I haven’t figured it out yet, but I really want to: This morning, when I was searching my old backup drives for data for my friend, I came across my favorite oceanography riddle of all times (which is still, as far as I know, unsolved!).

In 2012 and 2013, I went on cruises in the area of Hardangerfjorden, and there is one place that I find very intriguing: A narrow straight, connecting Hardangerfjorden in the south to Bjørnafjorden in the north. This straight is called Lokksund, and in its narrowest bit it’s only something like 20 meters wide and 30 meters deep. Which, as soon as water levels on both ends of the street are not exactly the same, leads to pretty strong currents.

In the description of Norwegian shipping lanes, it says about Lokksund “in the narrow part of the straight, the tidal current can be strong, up to 3-4 knots during spring tides, shifting direction every two hours. It goes southward for two hours before high tide, stops at high tide, goes north for two hours after high tide, and so on. … If there is constant wind from the south, the current can go continuously northwards. For wind from north or west, the same situation can happen with southward currents” (Den norske los 3, Farvannsbeskrivelse, Jørem Rev-Stad, 2006).

That the current is very strong in the straight was fairly obvious, and captain and crew were understandably not too happy that we wanted to spend a lot of time there (funnily enough, it’s Lokksund you see on the map on the screen in the picture below! Clearly, I really wanted to go there!).

Screen shot 2012-03-09 at 6.24.50 PM
On the bridge, discussing the scientific plan for the next day. Picture courtesy of Angus Munro.

However, the current directions that we observed didn’t seem to agree with the farvannsbeskrivelse, but they also did not seem to agree with tides from mooring data we had from north and south of the mouths of Lokksund. So we ended up doing a repeat CTD station just north of Lokksund. The CTD data is very interesting:

Above, you see a plot for salinity, and below for temperature. And there is a strong interface in both S and T — approximately at sill depth! — that is oscillating with the same frequency as described in the farvannsbeskrivelse, although from what I remember the timing was somehow different from what we expected based on the tides from the mooring data we had available.

Also, looking at how narrow the straight is, even with peak speeds of 3-4 knots, the volume of water that can actually go through Lokksund is actually very small. So even though the mixing in the narrow spots with high speeds is probably very high, the volume of displaced water is still very very low, and it’s not even clear how big its influence on mixing between the two fjords is.

But that’s not what makes me so intrigued: It should be such an easy system to understand: A narrow straight and water levels on either end driving the flow through the straight. Right? Except there is clearly more to it, and I wish I could go back there and figure out what that is!

I know for a fact that to this day, some of the crew vividly remember the time we spent in Lokksund during that cruise, and that they don’t have the fondest memories of being in a narrow straight in a strong current in the dark. But I still think it was good we spent all that time there, and luckily Elin is taking on this riddle now, hope you will keep us posted on what you find! :-)

“Laboratory layered latte” – combining latte and double diffusion. Easily my favourite paper ever!

My friends know me well. Especially A&I, which was proven again when they sent me the link to an article about two things that I am mildly obsessed with: Latte and double-diffusive mixing.

My obsession with latte is a fairly recent thing, but I have been known to blog about interesting convection pattern in it (for example here). The obsession with double-diffusive mixing, however, is well documented for more than the last 12 years (for example when I am writing experimental instructionspoems or scientific articles about it).

The double-diffusive process that I have been most concerned with is salt fingering, because it is oh-so-pretty, and also fool-proof to create for teaching purposes (when you know how to do it).

Diffusive layering I seem have to be a little frustrated with, at least in teaching (but reading back this post now, it turns out that that was entirely my own fault and not my students’. Oh well, you live and learn! Isn’t this exactly the kind of stuff that makes for great teaching portfolios? ;-)).

And it also turns out that I did the experiments themselves all wrong. According to the article “laboratory layered latte” by Xue et al. (2017) I should not have been trying to carefully stratify a tank in order to see diffusive layering. Instead, I should just have quickly poured the lower density fluid into the higher density one, and layers would have formed by themselves!

So there is one thing that you won’t see any time soon:

Yep. Me drinking latte from any kind of vessel that doesn’t let me look at the stratification! I don’t know how I could ever have fallen into the trap of missing out on observing fluid dynamics while having my early morning coffee in the office. Now I urgently need a nice glass mug!

And you should go check out the article, it’s a really nice read. My new ambition in life: Write a fluid dynamics research article that applies the FD to some really cool, yet mundane, every day thing. Are you in, Elin? :-)

Xue, Nan and Khodaparast, Sepideh and Zhu, Lailai and Nunes, Janine K. and Kim, Hyoungsoo and Stone, Howard A., Laboratory layered latte. Nature Communications 8(1), 2017

The energy lab’s dry run. Or: I have a great team! :-)

At first, I wanted to call this blog post “behind the scenes of a school lab” until I looked through the pictures and realized that all I am showing is people sitting around my desk in my office! Actually, not only sitting — test-running all the experiments for our energie:labor!

First, here is Julian’s experiment on atmospheric CO2.

And here an experiment from Jonas’ station on the role of the ocean in the climate system. A candle below an air-filled balloon. Can you imagine what will happen next?

Yes, this.

Sorry about the jump in perspective — even though I knew what would happen I clearly didn’t expect it enough to hold the camera stable. Small consolidation that everybody else clearly jumped, too?

Anyway, the point of that experiment is to look at the heat capacity of air and water. I’ve written about this before, see here (where we also have pictures of bursting the water-filled balloon because this is how we roll. But only in the lecture theatre, not in my office… ;-)).

Below, we are looking at Jonas’ overturning experiment, apparently discussing the work sheets. It’s really great how well this team works together on developing all their materials, even though their personal styles span the whole spectrum of teaching styles!

But we were also having fun, or at least that’s what it looks like… ;-)

In the picture below, taken on the second day of our dry run a couple of days later, we are looking at Henning’s station on the ice-albedo-feedback. As Henning is sitting next to me and we are sitting around my desk, he’s unfortunately not even in the picture!

In the background of the picture above you see the next exciting station that Nicolas prepared (and big shout out to my office mate who didn’t beat an eye when she came in and the office was filled with all our equipment and smelled of vinegar and white spirit…

What the guys are doing on the picture below? Using a bike pump to increase the pressure inside that bottle to make a cloud in a bottle.

Worked really well!

And then, there comes the most sophisticated piece of equipment of the whole lab: Nicolas’ cloud chamber. I’ll only tell you this much for now: It’s awesome! And you should stay tuned for an upcoming publication on how to build it and how to use it in teaching. Because it’s that great!

Now I’m out of pictures, but there is one last thing I want to say: Thank you, team, you are awesome! :-)

My new school lab on energy in the climate system has been launched! :-)

Today was a very exciting day: We launched my new school lab on energy in the climate system! The “energie:labor” is finally up and running again!

Let me walk you through some of the stuff that is going on in the lab.

Below, you see Mirko, who leads the station on the hydrological cycle, and his group working on an experiment.

In the left jar, you see how much smoke a burning piece of paper makes. The students tried this in order to compare it with the jar on the right. Because what they see in there is not just smoke from a burning piece of paper, it’s steam from the hot water at the bottom of the jar — a cloud in the jar! And the burning paper was just added to provide aerosols as condensation nuclei for the clouds.

Another part of the energy puzzle of the hydrological cycle: How much do raindrops falling down on the ground actually heat up the ground? The students are looking at the wooden board on the floor, using a thermal imaging camera. They won’t see a lot when the bouncing ball hits, but they saw a clear signal with the heavy metal ball they used earlier! Kinda like what we did at the European Researcher’s Night (see here).

Now, they are documenting their observations.

And later, they are running an experiment looking at how much moist vs dry air heats up in that insulated container below the lamp to explore the greenhouse effect of water vapour. The setup of this experiment was developed by Julian who is leading a different station on CO2 in the atmosphere, but sadly I don’t have any good pictures of that station!

On the table next to the hydrological cycle team, there is Jonas, working on the role of the ocean in the climate system. Below, the students are dunking air-filled bottles into hot and cold water baths to watch how air expands and contracts depending on its temperature.

They seem to be having fun!

Later, the team at this station did an overturning experiment. I have tons of pictures of that experiment, because it is just super photogenic (or because I am just still fascinated every time I see it, who knows?)

They are using a very strong lamp to model the heating by the sun near the equator, and cold packs to cool near the poles.

And they seemed to enjoy playing with food dye!

We have two more stations (or three, including the CO2 station I mentioned above), one on clouds run by Nicolas, and one on ice-albedo-feeback run by Henning. Unfortunately I don’t have good pictures of those, either, but I will post pictures of our trial run soon, where they’ll be featured, too.

Let’s close this by looking at how we brought all our new experts back together (because each group only conducted one station, for which they had almost all morning) — by using the Monash Simple Climate Model! I’ve written before about how great it is in teaching (see here), and I am still a big fan!

The new “experts” on clouds, the ocean, the hydrological cycle, atmospheric CO2 and ice-albedo feedbacks explained their topics to the rest of their groups. And — surprisingly enough — in the model, you can switch on and off each of these processes individually and see what effect it has on climate!

I think this worked really well to engage students in discussions about the processes they had just explored, and how they work together. Although I want to work on the kind of questions that guide them through the model before the next class visits the school lab in January…

But all in all, I am very happy with how the launch went, and I am super grateful to my great team! Thanks, Jonas, Julian, Nicolas, Mirko, and Henning (from the left in the picture above)! Hope you are enjoying your well-deserved weekend!

And last not least: Thank you, Frank, for letting us borrow your pupils! They were the nicest group we could have hoped for!

Of cupcakes and ice cores

For a popular science presentation on climate change, I needed a simple illustration for how ice cores can be used as archives of past climates. Luckily, my sister and family were excited to do some early Christmas baking for climate science!

And playing with food colors is always fun…

I think I had too much fun playing, actually, the “ice core data” would have been a lot easier to interpret if the different layers were just laying flat!

I should probably noticed here already that the color pattern wasn’t as regular as it should have been for easy interpretation of the core data later…

But it was fun! And they rose beautifully even though we were a little afraid that the time between mixing in the baking powder and actually baking the muffins was kinda long (because we had to mix in all the different dyes…)

The really difficult part, it turns out, was the coring itself. I had wider-than-usual straws, but instead of just cutting out the core, it was really difficult to have them pierce through the crust, and they compressed the core much more than I had hoped.

You can kind of see where the core goes in the cross section, and how the different colors correspond to their old locations inside the cupcake. But somehow this worked much better in my imagination than it did for real!

And I have a new-found appreciation for food bloggers. It’s really difficult to take good pictures of food!

But in case you were wondering: They taste just like boring, non-rainbow muffins. And my niece liked them! :-)

How not to communicate climate change: Lessons learned from the movie “Frozen” #scipoem

Frozen

As this poem’s hero was chosen
Olaf, the snowman in Frozen
who dislikes the cold
(or so we’ve been told)
despite d’pending on it to stay frozen

He’s telling the world how excited
he is and how super delighted
of temperatures warming
but without informing
himself ‘bout whether he’ll be blighted

His friends, knowing better, don’t tell him
Which I actually find to be quite grim
Like when sci’ntists hush
Beat about the bush
That conditions for life are about to dim

Exactly what we see performing
In the movie with the warming
We experience daily
That people gaily
Neither communicate – nor hear! – a warning

“Winter’s a good time to stay in and cuddle
But put me in summer and I’ll be a —
Happy snowman!”*
Are you really sure, man?
No, Olaf, you’ll just be a puddle!

*Lyrics from the song “in summer” from the Disney movie “Frozen” (2013)

 

Observing the “melting ice cubes” experiment with a thermal imaging camera

Remember the melting ice cube experiment? Great!

Experiment: Ice cubes melting in fresh water and salt water. By Mirjam S. Glessmer

If I had the chance to teach an intro to oceanography or some other class where I have time with students over a longer period (these days I am mostly giving one-off workshops), I would actually use the thermal imaging camera to make a different point with this experiment than the one I have usually recommended it for.
I would first do the classical experiment to talk about density-driven circulation. This could be done either using dye (levels of difficulty would be something like 1) easy: freeze dye into the ice cube. 2) medium: let them observe what happens with clear ice cubes and only add dye once they’ve realized that the fresh water ice cube is melting much faster, but have a hard time figuring out why. In this case, drop dye onto the melting ice cubes. 3) no dye at all, but let people focus on condensation pattern on the cups as well as shapes of the ice cubes. I tried that for the first time a couple of weeks ago and it worked really really well. I think that’s my favourite way of doing the experiment now!
After students have done that experiment and we have moved on to properties of seawater etc weeks later, I would bring the same experiment back when talking about how water is transparent to visible light, but not to all other wavelengths. Because students will likely assume that they will see the same kind of pattern that they saw with dye (or that they sketched when they drew the mechanism), but actually, unless the plume of dense water is flowing right along the edge of the cup, they won’t be able to see it because they really only see the temperature of the cup itself and can’t “look inside” the way they can with their eyes. So at first, I would assume, they’d be a bit bored and annoyed to be presented with the same experiment again, until they realize that now the point is a very different one. (Since I haven’t tried to use that experiment in that way, I am not quite sure how it will work, I think it would be important to either hold the melting ice cubes in the middle of the beaker. That way, there is no cold plume along the edge of the cup, and students see cold water appearing at the bottom of the cup “out of nowhere”. Alternatively, one could ask them to look at the cup from the side opposite to where the ice cube is (they always float to the edge somehow), but maybe that would be giving too much away already?). So now the point would be to explain why we can’t see the sinking plume on the thermal imaging camera, and dependency of transparency of sea water on wavelengths of light. This can lead to ocean color, remote sensing, camouflage colors of animals, all kinds of other stuff. I think that could actually be exciting! What do you think?

Not an infographic, not SciArt, yet strangely satisfying: I drew my CV :-)

I’ve recently become interested in making infographics for science communication purposes. As in: I’ve been wanting to learn how to do it, but I’ve never gotten around to actually do it. So when I was asked for a one-slide CV the other day, I thought great! Let’s make it an infographic! Two birds, one stone: I get to try out something new for my #SciCommChallenge, and I end up with a cool CV. So today I will tell you the story of how that CV came to be.

First, I started out brainstorming what I wanted to include in the infographic, and what kinds of icons I could use to visualise my skills and expertise with. I quickly ended up with the idea of using a time line that wasn’t linear, but rather organised around the different cities I had lived in for my studies, my Master thesis, my PhD thesis, my PostDoc, my job post PostDoc, and the PostDoc position I am currently on.

When I started sketching, I realised that it would be very difficult to a) come up with ideas for simple icons that showed “physical oceanography”, “mentoring”, or “goal orientation”, and b) to either find those icons online (in c) a style that I liked and d) freely available). Plus I didn’t have a graphics software available beyond PowerPoint. So the idea of sketching the whole thing seemed attractive.

I quite liked the sketch above in pen because it gave me a lot of flexibility with my less-abstract icons, but I wanted some color. So I settled on the design below, now in pencil:

This design I then filled in in water color. That was the first time since 2003 that I had used water colors (as I could see from the top sheet of my sketch pad, which was dated), and despite being a little apprehensive about it, it went quite well (if I say so myself).

So this is the finished product:

That picture was taken on my couch with really bad lighting, but I like how it turned out with the warm background of the paper. I also scanned the CV the next day, but it came out really weird, so I decided to stick with the photo.

The whole process of drawing this CV was really interesting to me.

For example, I had a drawing of a light house in the CV right from the very first sketch. For a while I didn’t really know what to do with it — I really liked it in the picture, but it didn’t seem to serve any purpose. Yes, I want to live in a light house eventually, but how was that relevant for a CV that was supposed to highlight skills and achievements? Until it occurred to me: The light house does actually reveal a lot about me: That I am really goal-oriented. I didn’t even realise it, but my goal-orientation had been on my CV all along, and that had been important to me without me being able to verbalise why! But now that I consciously included it, it all fell into place.

Or the process of drawing those goblets below the time line, for when I won a scholarship and a fellowship. Is it over the top to draw them like I won the world cup (or the Triwizard Cup)? Maybe. But it’s probably the first time ever that I have acknowledged to myself that both were achievements that I can actually be proud of.

I like how the theme of research ships, sailing ships, light houses dominates the whole CV. When I look at it, I feel like it represents me very well, like it captures my “why”, and creating it felt like things were falling into place. And even though I did not submit that CV in the end, to me, the whole process was definitely worthwhile and empowering.

And it definitely motivated to draw more. Stay tuned for some really cool SciArt to come as soon as I have found a good way to digitalize it! :-)

Melting ice cubes experiment — observing the finer details

If you don’t know my favourite experiment for practically all purposes yet (Introduction to experimenting? Check! Thermohaline circulation? Check! Lab safety? Check! Scientific process? Check! And the list goes on and on…), check it out here. (Seriously, of you don’t recognize the experiment from the picture below, you need to read up on it, it’s awesome! :-))

dyed_ice_cubes_02

Susann and I got funding from PerLe (our university’s project to support teaching innovation) to add a couple of cool new features to Susann’s “intro to meteorology” lecture, and doing a hands-on experiment with 50 students in a lecture theatre in their second lecture was only one of the first of many more to come.

We used the experiment to introduce the students to oceanic circulation, and this experiment is, in my experience, very engaging and sparks curiosity, as well as being very nicely suited as a reminder that things are not as easy as they seem to be when you see those nice plots of the great conveyor belt and all the other simplified plots that you typically see in intro-level lectures. Especially understanding that there are many different processes at play simultaneously, and that they have different orders of magnitude and might act in different directions helps counteract the oversimplified views of the climate system that might otherwise be formed.

I usually use dye to make it easier to observe what’s going on in the experiment (either by freezing it directly into the ice cubes as shown in the picture on top of this blog post, or by dripping it onto the melting ice cubes when students have started to observe that — counter to their intuition — the ice cube in the fresh water cup is melting faster than the one in the salt water cup).  We had dye at hand, but I decided on the spur of the moment to not use it, because the students were already focussing on other, more subtle, aspects that the dye would only distract from:

The shape of the ice cubes

In many of the student groups, the most prominent observation was that the shape of the melting ice cubes was very different in the fresh water and salt water case. In the fresh water case, the ice cube melted from the sides inwards: as a cylindrical shape with a radius that was decreasing over time, but in any instance more or less constant for all depths. In the salt water case, however, the ice cube melted upwards: The top did not melt very much at all, but the deeper down you looked the more was melting away. Why?

Condensation on the sides of the cup

Another observation that I prompted was in what regions the cups showed condensation. In the fresh water case, there was a little condensation going on everywhere below the water line, and sometimes there were vertical streaks down from where the ice cube was touching the wall. In the salt water case, there was only a small band of intense condensation close to the water level.

This, not surprisingly, looks very similar to what a thermal imaging camera sees when observing the experiment (as described in this post).

screen-shot-2017-06-11-at-17-12-55

Taken together, those two observations are quite powerful in explaining what is going on, and it seemed to be a fun challenge for the students to figure out why there was condensation on the outside of the cups in the first place (does condensation occur in warmer or colder places?), what it meant that different places ended up being warmer or colder, and how all of that is connected to global ocean circulation. Definitely an experiment I would recommend you do! :-)

Seeing is believing — A #scipoem

Seeing is believing

Climate change communication
Needs a good vis’alization
Political protesters and
politicians should best be shunned
to avoid defens’ve reaction’.

Show behaviour in relation:
not one car, but road congestion.
action’ble steps that can confront
Climate change…

Use real people’s real emotion
unfamiliar, thought-provoking.
Not overwhelmed, but rather stunned,
that’s how people best understand
unconscious habits’ implication’.
Climate change…

*This poem is a „rondeau”, and it is based on the findings in the “Climate Visuals – 7 Key Principles for Visual Climate Change Communication” report (http://climateoutreach.org/resources/visual-climate-change-communication/)