Deutsch, bitte!

 

Deutsch, bitte!

Aaaah… full panic! It is three o’clock on a Friday afternoon. All the cargo that is being sent to me from Sweden to Polarstern is missing some mysterious export declaration number, it is stuck in customs and can’t be loaded it until the right number is on the right document. Sven, an extremely helpful technician at Gothenburg’s University is in contact with a German company that hopefully can help us obtain the missing numbers…  all of a sudden I get an e-mail from him saying that they need a detailed description of all the goods and its intended usage – in German. Now. I did two years of German back in high school – and I’ve brushed it off a bit lately with Duolingo since I know I’ll spend most of the winter on a German ship… But I’m not quite at the point where I can describe oceanographic instrumentation on the fly. I start with google translate – while desperately calling everyone I know who speaks German. No Nadine, No Mirjam… but Stefanie finally saves my day and makes sure that the text that google translate has produced isn’t just garbage. The document is on its way through cyberspace to the German company – and I’m back to correcting my student’s lab reports. Luckily, they are not in German!

Meet Vår Dundas – and follow her on her journey to Antarctica!

When asked whether you want to go to Antarctica during regular times, there’s just one sensible response. When asked whether you want to go to Antarctica during highly unusual times, there’s still really only one possible response – you grab the opportunity with both hands, and you go to Antarctica. In a week, I’m starting a slow but steady journey towards Antarctica. I thought I’d write a bit about everything that’s happening now, the plan for the cruise and preparations. But first, since this is my first contribution to the blog, I’ll start by introducing myself.

Vår Dundas started working as a PhD-student with Kjersti and I this summer – now she is off to Antarctica. Photo: Private

I’m Vår, and I started my Ph.D. this summer at the Geophysical Institute in Bergen with Elin and Kjersti as my supervisors. Right now, I’m working with mooring data from the Amundsen Sea, but the next step is to begin a combined model and mooring study from the Weddell Sea. There, I’ll be looking mostly at shelf-break interactions at the Filchner trough opening and look for wind-field conditions favorable for far-reaching on-shelf heat transport.

Since I started working with Antarctic oceans, I’ve had a small hope that I would get the chance to join a cruise and go there sometime. So when I one Monday morning in the middle of October opened my inbox to find an email with the header ‘cruise’, stating that there was a possibility that I could travel to Antarctica this winter, I was slightly speechless and very excited. After a week or so with anticipation, I got a confirmation that I would be able to join the cruise. Since then, the practical details have started to dawn on me: In total, we’ll be gone for two months (including Christmas and new years). Of these two months, we will spend about 7 to 10 days in Antarctica. So how does this add up? Due to Covid, we start off by spending one week in isolation at a hotel in Denmark. After this, we board the ship but need to stay in port for a week to finish our two quarantine-weeks.  We then start our transect southwards, which takes four weeks. Reaching Antarctica, we do our science for 7 to 10 days (fingers crossed for 10) before a week-long transit takes us to Cape Town, and we fly home. I realize that I dread the first week of isolation, but then again, when you’re able to go to Antarctica, there’s just one sensible response.

The Norwegian Polar Institute is organizing the scientific work on this cruise. In total, the science team will consist of five people: Tore Hattermann, Kirsten Forssan, Sebastien Moreau, Julius Lauber, and myself. The plan is to make our way to the Fimbull Ice Shelf, where they have moorings that need some updates. These moorings are located along the continental shelf-break, where the ocean depth suddenly drops from a few hundred meters to about 2000 meters. Processes along this shelf-break are crucial for the southward flow of warm water, and consequently, important for how much the ice shelves melt. These moorings are also upstream of known regions where warm water flows in under the Fimbull Ice Shelf, where other moorings are located. A mooring array here can therefore provide valuable information on how upstream conditions affect the Fimbull Ice Shelf.

The Fimbull Ice shelf (Photo credit: NASA/Goddard Space Flight Center Scientific Visualization Studio. Additional credit goes to Canadian Space Agency, RADARSAT International Inc. )

In addition to the mooring retrivement and deployment, we will run a couple of CTD-sections (conductivity for salt content, temperature, density) and (hopefully) measure turbulence along the ice shelf front and underneath the fast-ice cover. If the weather permits it, we will also go onto the ice and measure properties underneath the ice.

The ship we are traveling with is not a usual scientific ship, but a freight ship, traveling southward to supply the Troll station. This means that it does not have the scientific equipment installed – we have to make a make-shift scientific deck with labs and winches ourselves. If this works out well, it will open up for new possibilities, where scientific data collection and supply missions can be done all at the same time, which is actually quite exciting.

Right now, I’m trying to get my head around everything I have to get done before I leave. It’s challenging to think about learning how to use the MSS-instrument and remember to download all the data I think I might want to work with for the next two months, at the same time as deciding how many woolen socks I need and what I’ll wear for Christmas. Still, I just shipped off one bag to the ship, I’ve gotten my health and teeth certificates signed, so I think I’m getting there. And there’s still one week left before I’m off.

Written by Vår Dundas.

UN9031 on the road!

Algot Peterson and bright orange buoys that are to keep my moorings upright in the Weddell Sea. Photo: E. Darelius

My five pallets with equipment for this winters expedition to the Weddell Sea is now finally on their way to Bremerhafen & Polarstern! Many thanks to Helge and Algot for helping me packing and preparing – and to Tor for taking over when they ran away with Ilker to the Barents Sea, leaving me to finish up all the paper work – freight lists and proforma invoices are luckily not part of my standard vocabulary, but during the last couple pf weeks it feels like I’ve been doing nothing but that… and I’ve definitely learnt more about dangerous goods and codes like UN9031* and LQ** than I ever wanted to know! I do appreciate that Helge & Algot are back ashore!

*Li-batteries contained in equipment

*Low quantitity

Stefanie’s current!

Although the Ocean still holds many secrets, it’s not very often nowadays that oceanographers discover new currents – but earlier this week one could read in NatureCommunications (and on nrk.no, in Norwegian) that scientists have drawn a new arrow on the map showing current systems in the North Sea! The “new” current brings dense water eastward along the Greenland-Scotland ridge from Iceland towards the Faroe Bank Channel, through which the dense water continues southwards into the North Atlantic.

I was very excited (and admittedly a litte bit proud!) to read about the discovery – since the paper is written by Stefanie Semper – the very first Master’s student that I supervised on my own. Stefanie has just submitted her PhD-thesis here at UiB, and I’m certain she will continue her great scientific work and that I’ll have the pleasure to read about her findings in the future!

The name of the current? Well, it’s not officially “Stefanie’s current” (although I’ll think of it as that) , but the slightly more descriptive (although boring) “the Iceland-Faroe Slope Jet”.

Stefanie’s current – (or the Iceland-Faroe Slope Jet) is the black arrow that originates north of Iceland and continues eastward towards the Faroe Bank Channel. From: Semper et al, 2020, Nature Communications. CreativeCommon License 4.0

Science is a team sport

The upside of the pandemic is that a lot of interesting meetings and presentations are streamed and recorded so that one can “shop around” and participate & listen without worrying about neither time zones nor CO2 and travel budgets.

Last night I had the pleasure to listen to Fiamma Straneo’s lecture “Ahoy captain, is that a glacier up ahead? Lessons learnt from working in Greenland’s marine margin” which is part of the International Glaciological Society Global Seminar Series (freely available here). I write “listen”, since the children’s drawers were empty and I had to do laundry at the same time – so I probably missed out on a lot of nice graphics and photos from the Greenlandic fjords that she was talking about… but I did not miss out on her conclusions:

Fiamma Straneo’s conclusions during the her talk in the IGS Global Seminar Series (https://www.youtube.com/watch?v=QpvjxoNWSLc)

Fiamma, who is a physical oceanographer working at Scripps while holding a Prof II position at UiB, and who is very much a team-player herself, used examples from her own research – from multi-disciplinary field campaigns in remote fjord arms to the (equally) multi-disciplinary and diverse team that stands behind the ISMIP6 projections –  to support her conclusions, and she did so very convincingly. Science is indeed a team sport!

Welcome to GFI, Mari!

Yesterday Mari Myksvoll visited me and the oceanography group at GFI and we had a nice chat about fjords, oceanography, and everything in between! We are lucky to get to see Mari more regularly in the hallways from now on, as she soon will be joining us (20%) as an Associate Professor II. The paperwork is not yet in order, but the university administration better hurry up since the plan is that she will be teaching GEOF337, the master’s course in fjord oceanography, next semester. With her background in fjord and coastal modelling – and with her enthusiastic smile – I’m sure she will do a great job! And I will for sure enjoy to have another female*, fjord-interested oceanographer around! Welcome to GFI, Mari!

Mari S. Myksvoll will join us at GFI as Ass. Prof. II next semester!

* number three in the teaching staff

Hipp Hipp Hurray!

Corona is turning our lives up side down – but that’s no reason not to stand up and sing “Happy Birthday” to Prof. Emiritus Arne Foldvik who turns 90 years old today! (Those of you who read Norwegian can read about him here)

Arne started out his scientific carrier as a meteorologist, studying among other things the waves that are generated when wind blows over topography  (he did that using the long tank down in the basement of GFI where I’ve taken my students to play with Nansen’s dead water) – but he later turned to oceanography.  Around the time when I was born he led his first Norwegian oceanographic expedition to Antarctica and the southern Weddell Sea. During that expedition he found what the Americans had failed to find a few years later: The Filchner overflow, an enormous* under water river that carries cold and dense water from the Filchner-Ronne ice shelf cavity to the bottom of the Weddell Sea. This discovery is one of the reasons I’m working with polar oceanography today, as I spent the three years of my PhD revisiting the exciting data that Arne & co had collected in the outflow.

The last time Arne came by my office, we chatted about towed icebergs, melting ice and the experiment I did in my “Nansen’s memorial lecture” (which Arne attended). Arne has been involved in projects where the aim has been to tow icebergs from Antarctica to dry areas in demand of freshwater (originally the middle east, and just a few years ago, to South Africa ). Arne told me, that if one did that, one would get ice into water warm enough, that the results of my experiments would no longer hold.

The density of seawater is a non-linear function of temperature and salinity, and while salinity dictates the density for cold water (causing the lines of constant density to be almost vertical in the TS-diagram below), temperature is more important for warm water (causing the lines of constant density to tilt more). So, that means that while the (fresher and colder) melt water mixture is lighter than the ambient water if it is cold, it will actually be denser if the ambient water is warm enough! Off course we had to try this out – I never got around to doing so, but yesterday, Mirjam finally did!

Somewhat disappointing – we realized that the result is more or less the same, independent of the water temperature. Does that mean the physics (and Arne) are wrong??? Probably not, it probably just means that the molecular diffusion of heat is acting fast enough that the “cold” melt water mixture doesn’t stay cold enough to sink 🙁

Anyway, here’s a stratified toast to Arne Foldvik!  HAPPY BIRTHDAY!

Temperature-Salinty diagram for cold and warm water. The dashed lines are lines of constant density (increasing density to the right) and the red line is a “Gade line”, which shows how temperature and salinity decrease as ice melts in seawater.

 

 

 

 

* 1.6 million cubic meters per second – that is almost ten times the Amazon river

Moviestar for a day?!

A while ago I was asked by the university (#realfaguib) if I wanted to present myself and my work in a short movie that they want to show to future students – and a few days later I found my office occupied by cameras of different sizes and three very nice journalists/moviemakers/photographers that came along. I quickly realized that making a short movie – I think they only want a minute or two – takes a loong time! Repeat, repeat, repeat – look into the camera, walk faster, walk slower, one more time, slower, shorter, clearer, louder, start over, look that way, look here, smile, don’t smile… at the end of the day, I was quite happy that I’m not a Hollywood movie star but an oceanographer in Bergen

 

Camera – and light – invasion of my office!
Kjersti and me doing our best to ignore the camera…

I think the movie will be released  shortly – but until then you can enjoy the nice article they wrote to go with it (in Norwegian)

We’re in Nature!

I remember vivid discussions with Anna over a loaf of freshly baked bread from our new bread machine. We were in the Southern ocean, somewhere in between New Zealand and the Getz Ice shelf in the Amundsen Sea on board the Korean icebreaker Araon and we talked about the moorings we were about to deploy, the proposal we have started writing, the experiments we wanted to run – but most of all we talked about what actually happens when ocean currents meet an ice shelf front. That was four years ago – and I’m super excited to see that a few days the results of those discussions (and a good deal of work on board Araon, on and around the rotating Coriolis platform in Grenoble and in numerous offices around the world) were published in Nature! Ice front blocking of ocean hear transport to an Antarctic ice shelf by A. Wåhlin, N. Steiger, E. Darelius, K. M. Assmann, M. S. Glessmer, H. K. Ha, L. Herraiz-Borreguero, C. Heuze, A. Jenkins, T.W. Kim, A. K. Mazur, J. Sommeria and S. Viboud – in Nature! (For those of you who are not into peer reviewed litterature and scientific publishing – this is probably scientific equivalent to an Olympic gold medal!)

So what did we find out – well, to make a long story short – we oceanographers talk about two types of currents. They are both driven by pressure gradients – but for what we call barotropic currents, the pressure gradient is caused by differences in sea level (i.e. in how much water there is) while for baroclinic currents, the pressure gradient is caused by differences in density (i.e. how heavy the water is).  The barotropic current is depth independent – this means that the current is equally strong from the surface down to the bottom, while the baroclinic current changes in strength (and potentially in direction) with depth. Our observations showed that the currents bringing heat towards the Getz ice shelf had both a barotropic and a baroclininc (bottom intensified) part. The barotropic part was the stronger one and the one carrying the majority of the heat. But when the current reached the ice shelf front (Anna was brave enough to deploy a mooring only 700m from the ice shelf front)  – the strong barotropic current had to turn, and only the weaker baroclinic current was able to enter the ice shelf cavity. The experiments at the rotating table showed the same thing – barotropic currents turned at the front, while baroclinic currents could enter.

Experiments at the Coriolis platform in Grenoble – a 13 – m large combination of a swimming pool and a merry-go-round!

You can read more about what we did in the Coriolis lab here, and about when Karen recovered the moorings here

All moorings are onboard!

Congratulations to @MarkusMelin4 and @cisprague who has recovered four out of four moorings in the Amundsen Sea! Despite fishing vessel rescue-operations, iceberg-on-top-of-mooring-problems and strong winds the four moorings and all of the instrumentation are now safely on deck! One of the top boys had suffered from an iceberg encounter and the connector plug on my ADCP (A large instrument that measures the current velocity in the water column using acoustics and Doppler theory) had been leaking…. but that’s just little scratches when you consider that they’ve spent two years in the water!

I look forward to see what the records has to tell us about the currents and the hydrography around the Getz ice shelf. Stay tuned!

Uff – seawater can do horrible things to instruments. Luckily it can be repaired! Photo: Markus Melin