CR
Cryospheric Sciences

Nanna B. Karlsson

Nanna B. Karlsson is a post-doc at the Alfred Wegener Institute for Marine and Polar Research in Germany. She is using radar data and ice flow models to look for the oldest ice in Antarctica: Ice that is more than 1 million years old. She is also involved in projects looking at ice on Mars, Greenland and northern Norway. She tweets as @icymatters .

Polar Exploration: Perseverance and Pea Sausages

Polar Exploration: Perseverance and Pea Sausages

Born on this Day

Portrait of Ludvig Mylius-Erichsen by Achton Friis. [Credit: Danish Arctic Institute].

On this day in 1872 – 145 years ago –Ludvig Mylius-Erichsen, Danish author and polar explorer, was born. He led two expeditions to Greenland and successfully mapped the then unknown northeastern part of the country. The second expedition was his last. The expedition was surprised by an early onset of spring and could no longer use their dog sledges. The two Danes, Mylius-Erichsen and Høeg Hagen died in November 1907 of cold and hunger. Their bodies have never been found. The last remaining expedition member, the Greenlander Brønlund, continued the journey alone but perished a few weeks later. His body and the expedition diary was found in 1908.

Thousands of Pea Sausages

The tin on the image above contains “pea sausage” and was essentially the world’s first ready meal: A mixture of ground peas, beef fat, bacon, spices and salt. Pea sausage was invented in 1867 in Germany and was a common part of military and expedition rations up until the beginning of the 20th century.

Mylius-Erichsen’s expedition brought along 1756 tins of this kind. Each tin contained 6 tablets of pea sausage, that mixed with ¼ water would make a nourishing soup. And the taste? On his first expedition, Mylius-Erichsen wrote:

“The evening meals in the three boxes consisted mainly of different kinds of sturdy soups, black pudding, meat pie, beef, pea sausage and sizeable portions of vegetable such as cabbage, beans and carrots. We only used one third of the evening meal rations on the way out. We did not like the taste of the meat but black pudding, peas and the different kinds of soup were heavenly”.

And later:

“Jørgen and I had dinner at Amarfik’s, and dinner consisted both days of little auks boiled in our last portion of pea sausage – a wonderful dish…”

Members of Mylius-Erichsen’s first expedition: Brønlund, Bertelsen, Mylius-Erichsen, Rasmussen and Moltke. [Credit: Danish Arctic Institute].

Photos and descriptions are from the Danish Arctic Institute (@arktiskinstitut) where you can also see a full 360 degrees photo of the tin.

Check out more historical footage from Greenland in a previous Image of the Week showing aerial photos from the 1930s.

Edited by: Sophie Berger

Image of the Week – The Sound of an Ice Age

Image of the Week – The Sound of an Ice Age

New Year’s Eve is just around the corner and the last “image of the week” of 2016 will get you in the mood for a party. If your celebration needs a soundtrack with a suitably geeky touch then look no further. Here is the music for climate enthusiasts: The sound of the past 60,000 years of climate. Scientist Aslak Grinsted (Centre for Ice and Climate, University of Copenhagen, Denmark) has transformed the δOxygen-18 values from the Greenland NorthGRIP ice core and the Antarctic WAIS ice core into music (you can read more about ice cores in our Ice Cores for Dummies post). Using the Greenlandic data as melody and the Antarctic data as bassline, Aslak has produced some compelling music.

You can listen to his composition and read more about his approach here.

The δOxygen-18 values are a measure of the isotopic composition of the ice, and they are a direct indicator of temperature. The image of the week above shows the isotope values for the past 20,000 years as measured by polar ice cores. On the left-hand side, we are in present-day: an inter-glacial. The δOxygen-18 values are high indicating high temperatures. In contrast, on the right-hand side of the figure we are in the last glacial with lower δOxygen-18 values and lower temperatures. One remarkable thing about these curves is how fast the temperature changes in Greenland (top) compared to Antarctica (bottom). This delayed coupling is called the Bipolar Seesaw.

The clefs are our own addition of course. We have not included the time signature because who knows what the rhythm of the climate might be? (Personally, I think it might be in ¾ like a waltz: An unrestrained movement forward with small underlying variations).

The data from Antarctica is published by WAIS Divide Project Members, 2015. The Greenlandic data can be found on the Centre for Ice and Climate website and in publications by Vinther et al., 2006, Rasmussen et al., 2006, Andersen et al., 2006 and Svensson et al., 2006.

Happy New Year!

 

Image of the Week — Listening to the Snow

Image of the Week — Listening to the Snow

When working in the middle of an ice sheet, you rarely get to experience the amazing wildlife of the polar regions. So what are we doing hundreds of kilometres from the coast with an animal tracker device? We are listening to the snow of course! It is not crazy; It is what Image of the Week today is all about!


Going Wireless

E. Bagshaw testing the range of an ETracer in a 12m borehole at the bottom of a 2m deep snow pit. [Credit: N. B. Karlsson].

E. Bagshaw testing the range of an ETracer in a 12m borehole at the bottom of a 2m deep snow pit. [Credit: N. B. Karlsson].

In June 2016, Liz Bagshaw and I travelled to the EGRIP (East Greenland Ice Core Project) camp to test a handful of wireless sensors named “ETracers” in a new setting. The “wireless” part is very important, because it means that we can make measurements without having to connect our instrument to a cable, which may fail or snap. Instead, the sensors transmit all their data as radio waves. We use the same frequency that biologists use for tracking animals – although there weren’t many to see in the middle of the Greenland Ice Sheet!

The ETracer sensors were originally developed for measuring the meltwater under the ice at the margin of the Greenland ice sheet. We wanted to test if they could also tell us something about what is going on in the snow.  For example, how does the snow temperature change and how is the snow compacting in different parts of the ice sheet? These questions might seem theoretical but their answers are important when working with data from satellites, since the satellite measurements may be affected by different snow conditions.

Pink Baubles

The ETracers stacked on small magnets. This temporarily stops their bleeps [Credit: E. Bagshaw].

The ETracers stacked on small magnets. This temporarily stops their bleeps bleeps and is an efficient way of silencing them while we are listening for other ETracers [Credit: E. Bagshaw].

Armed with an antenna (see image of the week), radar receivers and what looked like small pink plastic baubles we set to work. The pink baubles are in fact the ETracers – small devices that contain temperature, pressure and conductivity sensors.  First, we used a 60m deep borehole that was drilled earlier in the season. In order to test the range of the Etracer we lowered one to the bottom of the hole. We set up the antenna and receiver at the surface, and started listening for the ETracer signal.  We were very pleased when the Etracer sensor happily chirped back informing us that it was below -30 degrees C at the bottom of the hole.

Our colleagues had also drilled several 12m boreholes for us, and we now installed ETracers at the bottom of the holes as well as on the surface. For over a month, the ETracers sent back information to our receivers on the ground about temperature, pressure and conductivity of the snow.

We are still analysing our data but the most important part of our work is done: we have shown that the ETracers can accurately measure the properties of the snow. Next year, we will return to the camp and set up more experiments. Stay tuned – or rather keep listening!

You can read more about setting up the EGRIP camp in a previous Image of the Week post “Ballooning on the Ice“.

Edited by Emma Smith and Sophie Berger

Image of The Week – Ballooning on the Ice

Image of The Week – Ballooning on the Ice
A curious experiment is taking place in Greenland. An experiment involving very large balloons and – of course – a lot of snow. Read on to discover why balloons are an environmentally friendly tool when constructing an ice core drill camp.

Last year, a small team traversed 400km from northwest Greenland to the EastGRIP site (read more about the traverse here). This year another strenuous task is waiting: setting up the camp and getting everything ready to drill through the largest ice stream in Greenland: The North East Greenland Ice Stream.

What about the balloons then?

When drilling an ice core it is convenient to set up the drill in a place that is sheltered, so that the drilling operation is not hampered by bad weather. It is also best if the ice core is handled in areas where the temperature is not too high. The obvious solution is to dig out caves under the surface of the ice sheet. They provide both a shelter for the weather and a natural cold room. At previous camps, the underground caves or “trenches” have been constructed with wooden beams as a ceiling. However, after several years of snowfall the beams will start to collapse under the weight of the newly accumulated snow.

This year, scientists at the EastGRIP project are attempting a different and completely new approach. Relying on the fact that a dome-shaped ceiling is a very stable construction, the trenches are built using very large balloons. The construction process is quite simple although like all polar fieldwork it also requires hard work.

Pictures by S. Kipfstuhl combined to show the construction of the balloon trenches.

Pictures by S. Kipfstuhl combined to show the construction of the balloon trenches.

First, trenches are dug out of the snow with snowblowers. The balloons are then laid out in the trenches and inflated. Once they are fully inflated they are covered in snow and the snow is left to settle for a couple of days. The balloons are then deflated and beautiful caves appear. After a bit of tidying up, the caves can be outfitted with drills, equipment and other necessities.

A look into the beautiful caves left behind when the balloons were deflated. Credit: S. Kipfstuhl.

A look into the beautiful caves left behind when the balloons were deflated. Credit: S. Kipfstuhl.

And the environmentally-friendly part?

Transporting material into the middle of an ice-sheet is an expensive process that is done via aircrafts fitted with skis. The heavier the material the more fuel is needed for the transport. The wooden beams previously used are heavy and therefore require a lot fuel to transport. On the other hand, balloons are substantially lighter, can be reused for building new trenches and are not left behind as waste. An ingenious solution to a very unique problem!

The EastGRIP project is a lead by Centre for Ice and Climate, University of Copenhagen, Denmark with several international partners and air support from the US Office of Polar Programs, National Science Foundation. You can follow the camp on twitter for photos and updates on daily life on the @egripcamp twitter account.

A balloon ready to get inflated. Credit: S. Kipfstuhl.

A balloon ready to get inflated. Credit: S. Kipfstuhl.

An Antarctic Road Trip

An Antarctic Road Trip

Working in the Arctic and Antarctic presents its own challenges. It is perhaps easy to imagine how a station situated close to the coast is resupplied: during the summer, one or more ships will arrive bringing fuel, food and equipment, but what about stations inland? Flying in supplies by aircraft is expensive and, in the case of large quantities of fuel, unsustainable. Besides, many stations are closed during the winter season, so there is nowhere for a plane to land until the skiway has been reestablished. The answer is of course that you drive. In other words, you go on a polar road trip, and one such road trip is the traverse that starts every year from the German Neumayer III station. The route is almost 800km long and it typically takes the traverse team 10 days to make their way across the East Antarctic Ice Sheet to their goal: Kohnen station at 75 degrees S, 0 degrees W and 2.9km altitude.

This year I got the chance to join the traverse and do a bit of science along the way with my colleague Anna Winter. Read below for a riveting tale of hardships, drilling and bamboo poles!

Map of our traverse route starting at the Neumayer III station on the coast. Credit: Anna Winter.

Who is holding up the traverse?

If you were to look at the traverse from above, you would see six large “Pisten bullies” pulling several sledges, each leaving a track across the ice sheet. However, you would also see two people on a tiny vehicle; a skidoo with two small sledges. Some times the skidoo will be in front of the traverse train, but often it will be trailing behind, and you would definitely notice that the people on the skidoo are stopping frequently. The two people are Anna and myself. We had set out to investigate how much snow is falling in this part of the Antarctic, and to do this we used a range of equipment from highly advanced radar instruments to bamboo sticks and a measurement tape.

Drilling into the past

The Antarctic ice sheet has a long memory. When snow falls, the old snow is buried, so when you drill down into the surface you go back in time and can look into the past. This is how we know what the climate was like in the past. Drilling an ice core all the way to the bottom of Antarctica takes a very long time: often 3 – 5 years or more, but since we want to know something about the very recent changes, we do not have to drill very far.

Drilling a firn core requires patience, focus and sturdy gloves. Credit: Anna Winter.

Drilling a firn core requires patience, focus and sturdy gloves. Credit: Anna Winter.

On the 31st of January the traverse stopped a bit earlier than usual, and while the drivers tended to the vehicles and the cook prepared the New Years Eve dinner, We started drilling a firn core (firn is old snow that is not ice yet) with the help of Alexander and Torsten. In order to drill a firn core,  you need a drill that can capture the firn inside, a small engine for powering the drill and several extensions so you can go as deep as you like (see photo). It is not an easy process and many things can go wrong. For example, it should not be too warm when you drill. A few metres into the snow the temperature is no longer the same as the air, but instead it is the average annual temperature. Since we are drilling in the summer time this means that the firn we retrieve will be maybe 20 degrees colder than the temperature at the surface. When the drill comes up the metal gets warm and the core will get stuck inside the drill. A real nightmare! This is also the reason why we drilled during the evening even if that cut our New Years Eve celebrations short. Fortunately, we did manage to get a break and enjoyed a delicious New Years Eve meal, before finishing the drilling ten minutes before midnight. We celebrated the success of the drilling and the New Year with a whisky, before the cores were packed in boxes so they can be shipped to Germany for more analyses at the Alfred Wegener Institute.

Measuring a the height of a bamboo pole includes high-technology equipment, namely, another bamboo pole with peanut-can and a measurer tape stuck to it. Credit: Nanna B. Karlsson.

Measuring a the height of a bamboo pole includes high-technology equipment, namely, another bamboo pole with peanut-can and a measurer tape stuck to it. Credit: Nanna B. Karlsson.

The endless row of bamboos

So, how do the bamboo poles fit in the picture? The firn core tells us a lot about the snowfall in the place where it was drilled, but we also want to know what is happening along the route of the traverse, and what is happening right now. Therefore, last year, bamboo poles were set up every 1km along the first part of the traverse. Our task was to increase the number of bamboo poles to one pole every 500m. We also measured the height of the old poles, and compared it to their original height. The further we got from the coast, the taller the bamboo poles were. This is what we expected since we know that very little snow falls in these parts of Antarctica, maybe less than half a metre a year! From our measurements, we now know directly how much snow has fallen since last year. Next year, other people will measure the height of the old bamboo poles and the new ones we put up, and we will know even more about the snowfall. It is a laborious and hard process: the traverse route is almost 800km so it is almost an endless row of bamboo poles. If only they could be seen from space they would make an impressive sight.

This blog post was originally brought on the website of the Alfred Wegener Institute in German. You can see more photos and read the originals here and here.

Tea break with Kottas Mountains in the background. For once we were ahead of the rest of the traverse. Credit: Anna Winter.

Tea break with Kottas Mountains in the background. For once we were ahead of the rest of the traverse. Credit: Anna Winter.

(Edited by Sophie Berger and Emma Smith)

Image of the Week: The Bipolar Seesaw

Image of the Week: The Bipolar Seesaw

The colourful graphs above show how the climate changed in the period from 65 to 25 thousand years ago when Earth was experiencing an ice age. A wealth of information on the dynamics of our climate is embedded in the curves, especially how the northern and southern hemisphere interact, and how fast climate can change.

The figure represents thousands and thousands of hours of work by scientists, technicians and logistics personnel.  It shows the latest results from analyses of an ice core drilled in the middle of the West Antarctic Ice Sheet: The WAIS ice core.

 

What are we looking at?

In the top part of the figure, the blue curve shows oxygen-isotope values from the North Greenland Ice Core Project. The curve represents temperature in the northern hemisphere where the peaks are high temperatures.

→  First take home message: During the last ice age, the temperatures in Greenland changed very abruptly from cold to warm temperatures. These changes are marked with yellow lines in the figure.

The green curve shows the amount of methane gas in the Antarctic WAIS core. The shape of the methane curve is very similar to the blue temperature (oxygen-isotope) curve from Greenland. The rapid changes in temperatures in Greenland are reflected in the amount of methane in Antarctica.

→ Second take home message: Methane is a “well-mixed” atmospheric gas. This means that if you measure the amount of methane in the air anywhere on Earth, you will get a good indication of the amount of methane on a global level.

The third and fourth curves show the oxygen-isotope values from WAIS (yellow) and the temperatures (purple). In contrast to the Greenland temperatures, the temperatures in Antarctica do not show very fast changes. Instead, we see a slow cycle of rising and falling temperatures.

→ Third take home message: When Greenland experiences a fast warming, Antarctica slowly begins to cool. When Greenland slowly cools, Antarctica begins to warm.

 

But what does it all mean?

It means that changes in temperature in the northern hemisphere affect the southern hemisphere but with a mechanism that is slightly delayed. This mechanism is of course the ocean. In climate science, this up-and-down pattern is called “the bipolar seesaw” (read more here).

 

Why is it important?

It is important because it tells us something about how the climate system reacts to abrupt changes. A change in the northern hemisphere is transmitted to the southern hemisphere but not necessarily immediately.

 

Want to know more?

Read the whole paper here.

Edited by Emma Smith and Sophie Berger

What to do at EGU  — a guide for early-career scientists

What to do at EGU  — a guide for early-career scientists

Are you going to the EGU General Assembly in Vienna next week? Check out these events for early career scientists.

To remind you when and where all these nice events and activities take place, you can directly view and import them in your electronic calendar (Isn’t it wonderful?! :-))

Social event for Early Career Cryosphere Scientists!

If you cannot make it to anything else; make it to our social event, which is organised together with APECS. After the short course on Wednesday evening (see below) we will head to the Wieden Bräu for some food, drinks and networking. We will be there at approximately 20.30. You do not have to sign up in advance, but if you know that you are coming it would be very helpful if you could let us know by filling in this doodle.

Here you can even find the event on facebook.

Meeting about the Cryosphere Blog

If you like this blog, are curious about it and would like to contribute to it  — directly and/or indirectly — please come and meet us on Tuesday the 19th of April at 12.15.

Short courses

The idea behind the short courses is to give an insight into a certain area and/or the applications/uses/pitfalls in and around the topic. There are a lot of very interesting courses at this year’s meeting and below we have highlighted a few of them. Why not drop by and meet the experts who have kindly agreed to participate and share their knowledge?

Cryosphere short courses

Using Ice core chronologies: Dos and don’ts  

Assoc. Prof. Anders M. Svensson from the Centre for Ice and Climate, University of Copenhagen will tell you all you need to know about ice cores. The course is an introduction to ice core science with an emphasis on how ice cores are dated, what the main uncertainties are, and what to be aware of when comparing with other records. The course is especially of interest to researchers who do not work directly in the ice-core community, but who find themselves using ice core data for comparison with other climate data and time-series, and who would like an introduction to what ice core records can and cannot provide.
Time and date: Wednesday the 20th of April, 19:00–20:00
Place: Room 0.31

Remark: This short course takes place just before the social event and it is said that learning heaps of stuff about ice cores is the best way to start your evening 🙂

 

The Cryosphere — Publishing Your Work: Meet The Editor! [Read More]

Image of Week: Blue Ice in East Antarctica

Image of Week: Blue Ice in East Antarctica

The blue ice areas of Antarctica are one of the most fascinating parts of the ice sheet. In these regions, snowfall is so low that the ice is laid bare by the wind and consequently sublimates. This exposes beautiful, blue ice surfaces, like an ocean frozen in time. This picture was taken at a site named “Windy Corner” by the Kottas Mountains, in the northernmost part of the Heimefrontfjella, Dronning Maud Land, East Antarctica.

Map of Antarctica showing the ice sheet (grey), ice shelves (dark grey) and known blue ice areas in blue. Credit: Quantarctica, Norwegian Polar Institute.

Map of Antarctica showing the ice sheet (grey), ice shelves (dark grey) and known blue ice areas in blue. Credit: Quantarctica Database, Norwegian Polar Institute.

You can also read about an expedition to another blue ice area on our blog.

Edited by Sophie Berger and Emma Smith

Image of the Week: Ice Sheets in the Climate

Image of the Week: Ice Sheets in the Climate

Ice sheets play a central role in the climate system. They store significant amounts of fresh water and are the conveyor belts for transporting snow that accumulates on land back into the oceans. The figure above shows a few of the ice-climate interactions. In the figure below (click on the figure for full resolution) we see the complete picture of the processes taking place between ice sheets, solid earth and the climate system. These interactions have an internal variability but also affect the coupled ice sheet–climate response to external forcings on time scales of months to millions of years. The inlay figure represents a typical height profile of atmospheric temperature and moisture in the troposphere.

If the current warming of the climate continues, the ice sheets will respond at a yet unknown rate, with unknown consequences for the rest of the climate system. Decisions reached at COP21 in Paris this week  may impact the future of our ice sheets and halt the current trend.

FigBox5.2-1_interaction_ice_sheet_rest

The interaction of ice sheets with the climate system. Credit: Figure 1 in Box 5.2, IPCC AR5.

Image of the Week: Atmospheric CO2 from ice cores

Image of the Week: Atmospheric CO2 from ice cores

The measurements of atmospheric CO2 levels at Manu Loa, Hawaii read 401.01ppm on the 7th of December this year. To understand the significance of this number, you just need to look at the figure above from the 4th IPCC report. It shows the changes in CO2 concentrations during the past 800,000 years based on ice core measurements. Values have fluctuated between 190ppm and 280ppm. In other words, both the level of present-day atmospheric CO2 and the rapidity of the increase is unprecedented.

The figure also shows the projections from the IPCC AR4 report for different emission scenarios. Which scenario will turn out to be the most likely might be determined at COP21 in Paris right now.

Read more:

Measurements at Manu Loa, Hawaii

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