Do you think it is possible to stand on an 18 cm thick sea ice floe without breaking through?
Just one week ago we almost got stuck with the ship in about 4 m thick sea ice further south. We couldn’t move south and not back north neither. This was scary and we already imagined how it would be to spend the whole Antarctic winter in the sea ice. As soon as the captain managed to break the ship free, he headed straight north to get out of the sea ice covered area. Although it was good to get into a safer area, we were disappointed that we didn’t get to do all the science we wanted to do closer to the ice shelves. And the most disappointing was that we didn’t get the opportunity to leave the ship and go on sea ice!
But suddenly before leaving the sea ice area for good we stopped for a sea ice station, because there was a perfect homogeneous ice floe that the sea ice scientists were eager to study. So four of the scientists were brought to the ice floe on a small boat and took sea ice cores to measure the thickness, temperature, salinity, phytoplankton content and chemical constellation. In the meanwhile, the rest of us sat in the day room watching them through the windows. We were very jealous at them who could get on the ice! At some point there was an announcement through the speakers: Everyone was allowed to go on the ice floe! This made us so happy that we all ran to get into the floating suits and to enter the small boat. Finally – after four weeks on the ship, we could get off and step onto a piece of ice! We were very excited, jumped on the sea ice, made pyramids, and took a lot of crazy pictures until our hands were frozen! It was amazing and a lot of fun also to see the ship from distance.
Although the ice floe looked very fragile and dangerous to step on, it was stable enough to hold all our jumps. It was fun and only the penguins were missing, but we could live with that. It was a great pay-off after the disappointment of heading north earlier than expected.
While Nadine is wathing icebergs drift by in the Southern Ocean, I brought the students in GEOF232 back to Masfjorden, a fjord just North of Bergen. No icebergs to be seen there (luckily), and the only thing we saw drift by was Our own DIY drifters that we had deployed in the fjord!
A drifter is simply an Object that drifts With the Ocean currents and then on a regular basis reports its position back. Now, you can pay a lot and buy a fancy drifter… or you can build Your own (almost as fancy). That’s what Our handy technician Helge Bryhni did! All you need is some paint trays, a bucket, flotation, some rope and chain – and one of these devices that you are supposed to put on your (expensive) car so that you can find it again if it gets stolen. To be on the safe side, Helge opted for a radar reflector and a water proof container.
Video by Algot Peterson, UiB
The students got to decide where and how to deploy our four drifters – spread out or together? in pairs with different depths*? near a river outlet? on rising tides or sinking tides? – and once they were in the water they could sit back and follow the drift on their mobile phone!
*by adjusting the length of the rope we could Place the bulky plastic part of the drifter on the Depth we wanted, and the drifter would then follow (and show us) the water motion at that Depth.
The editors of Geophysical Research Letters have selected yourpaper “Warm Circumpolar Deep Water at the Western Getz Ice Shelf Front, Antarctica” (MS# 2018GL081354) to be featured as a Research Spotlight on https://Eos.org and on the journal’s website. Congratulations!
Back to RV Kronprins Haakon, we celebrate the international women today! While Elin is active in Bergen at Women in Science 14.15 @ Realfagsbygget and Anna gets excellent data from AUV Ran under the Thwaites Ice Shelf, we collected all women for a group picture on the Helideck! About 40% of the scientists on board are women, plus 3 women from the crew!
The new Swedish AUV (autonomous underwater vehicle) heroine Ran has returned from her second mission beneath Thwaites ice shelf! Just in time for the international women’s day tomorrow!
An AUV is sent down in the water with a pre-programmed mission, e.g. “dive down to 500 m depth, swim 2 km to the east while measuring salinity and temperature and then come back here so that I can pick you up”, while a “ROV” (Remotedly operated vehicule) is connected to and steered from the mother ship via cables.
The name Ran is borrowed from Nordic mythology, where she is the goddess of the deep sea. According to the legend (and wikipedia), Ran catches seamen in big nets and then keeps them with her at the bottom of the sea. Luckily Ran escaped both the nets and the sea ice that was closing up around her pick up spot… and made it safely back to the mother ship were Anna Wåhlin and the rest of the AUV-team was waiting. I bet they were nervous!
On her second trip, Ran ventured three kilometers in under Thwaites, and brought back information on the sub-ice shelf hydrography and currents but also water samples that will be analyzed back in the laboratory.
Ran and I have one thing in common – neither she nor I would be where we are today without Anna’s support and stubborness. I’m so happy Your “baby” is successfull, Anna. You’ve worked so hard for this to happen! Congratulations!
You can read more about Ran and the expeditions (in Swedish) here!
Yesterday the weather finally allowed the technicians from the Nowegian Polar Institute (NPI) to leave the research station Troll and fly out to go treasure hunting on the Fimbull ice shelf! Two years has gone by since they last visited the sites where NPI installed sub-ice shelf moorings more than ten years ago… and where we two years ago installed an “ApRES”. While the sub-ice shelf moorings measure the temperature and the currents in the water beneath the ice shelf, the APRES measures how fast the ice thins, and we can then calculate the basal melt rate. When combining the records we can hopefully learn a lot!
Like most Places in Antarctica, the snow that falls on the Fimbull iceshelf never melts away, so there was a few meters of snow to dig through in order to reach the instruments and to download the oh so precious data – a true treasure hunt!
Judging from the photos, the solar panel system that Helge Bryhni, a technician here at GFI, helped me design in order to power my APRES, appear to have survived two Antarctic winters… and we are now eagerly waiting for the report on how they’ve performed… and to have a look at the new data!
More stories from the successful treasure hunt at the Fimbul ice shelf will appear at @oceanseaicenpi soon!
The Santa Claus at the Norwegian Research Council distributes his gifts already during the first weeks of December… and this year one of them landed on our desk! Our Project iMelt (which is short for “Ocean-ice shelf Interaction and channelized Melting in Dronning Maud Land”) led by Laura de Steur at NPI got funded!
10 MNoK to service moorings and installations on the Fimbull ice shelf, to hire a PhD-student and posdocs to analyse all the data we are and will be collecting and to numerically model the system we are studying 🙂
This is the Project summary form the Application:
The recent increase in the Antarctic contribution to global sea-level rise is a major concern given that the majority of the world’s population lives along the coastlines. This increase, which is now thought to be irreversible in West Antarctica, is triggered by ocean-induced melting beneath the floating parts of the ice sheet known as ice shelves. Most basal melting occur near the ice-sheet grounding lines and the ice-shelf fronts, as well as within basal channels underneath the ice shelves. This project will quantify the processes and importance of ocean-ice shelf interactions and channelized basal melting in Dronning Maud Land, East Antarctica. The main focus will be on Fimbulisen ice shelf which has a complex network of basal channels in the central part of the ice shelf and a tongue that extends seaward of the continental shelf. Under-ice shelf data has been collected at Fimbulisen since 2010 and new, planned infrastructure along the coast of Dronning Maud Land will allow us to investigate ocean processes outside the ice shelf. Three autonomous radars are also deployed on Fimbulisen and Nivlisen ice shelves to monitor ice-shelf basal melting directly. The Project will quantify the relationship between far-field ocean dynamics, ocean-ice interactions and basal melt rates through these concurrent oceanographic and under-ice shelf measurements. This interdisciplinary research combines in-situ measurements, satellite remote sensing, and high-resolution modeling of ice-ocean interaction in Dronning Maud Land and will provide fundamental new knowledge on processes related to basal melting, essential for a better understanding of the stability of the Antarctic ice sheet.
Antarctic ice shelves are thinnening at an accelerating rate, and they do so because oceanic currents bring warm water (heat) into their cavities causing them to melt from below. When they melt away, the ice sheet upstream accelerates, ice (mass) is moved from land to the ocean and the sea level rises, threatening to flood vast and densely populated areas. A part from cutting down our CO2 emissions there’s nothing we can do about it, or is there? We can off course build walls, or dikes, to keep the rising seas out like they do in Holland, but what if we built a wall that stopped (or at least slowed it down) the sea from rising?
Recently scientists from Princeton and Bejing Normal University suggested in the Cryosphere that in order to put off a potential collapse of e.g. Thwaites ice shelf (which is thought to be unstable and which is feed by a huge, marine based ice stream and thus has a potentially large impact on the sea level) further into the future we should simply build a large wall – not in Holland, but at the seafloor in Antarctica, in order to block the warm water and keep it from entering the ice shelf cavity. It sounds like science fiction – and the thought of constructing such a wall is more frightening than anything Hollywood can produce. The risks are huge, the environmental impact is enormous (and thats sort of the point of it) – but the consequences of not doing it may be likewise. Enormous areas would be flooded, millions of people would have to leave their homes as the sea keeps rising. A wall would only buy us time, it would postphone, not stop, what is happening around Antarctica. And it would have no effect at all on other consequences of global warming. We still need to cut down our emissions, sooner rather than later, to make sure that our children and grandchildren – and their children and grandchildren – can live on the planet we call home.
So, if to build or not to build is the question, what would be your answer?
I was interviewed by a journalist from Ekko, a Norwegian radio program, about the proposed wall and the melting Antarctic ice last week. You can listen to the program here (in Norwegian/Svorsk). I’m right at the end!
Antarctica has been in the headlines the last week – see e.g. the Guardian or Bergens Tidene – as a large group of scientists concluded in Nature that the Antarctic ice sheet has lost 2720 billion of tons of ice since 1992. 2720 billion tons… that’s enough ice to cover all of Norway with almost 8 m of ice… or to rise the mean sea level with 8 mm.
The uncertainty is large, especially for East Antarctica, because it is not easy an easy task to quantify the mass change of Antarctica. Over the years three main techniques have been developed, either building on satellite altimetry (measurements of the height of the ice sheet), gravimetry (measurements of the gravitational pull on satellites) or budget calculations (combining estimates of snowfall with estimates of ice loss at the boundary of the continent) – each with it’s own set of challenges and uncertainties. The author’s have combined results from 24 independent studies, using different methods and models, and the results are unambiguous: Antarctica has been losing mass and the rate of ice loss is accelerating.
Climate is changing; the ice loss is likely to continue and the sea level will continue to rise. It’s scary. I can go back into my office and try to understand more about what role the ocean is playing and about what is happening down south – but I cannot stop it. Not on my own. But maybe, hopefully, we can still do it together, all of us.