CR
Cryospheric Sciences

ice sheet

Marine Ice Sheet Instability “For Dummies”

Marine Ice Sheet Instability “For Dummies”

MISI is a term that is often thrown into dicussions and papers which talk about the contribution of Antarctica to sea-level rise but what does it actually mean and why do we care about it?

MISI stands for Marine Ice Sheet Instability. In this article, we are going to attempt to explain this term to you and also show you why it is so important.


Background

The Antarctic Ice Sheet represents the largest potential source of future sea-level rise: if all its ice melted, sea level would rise by about 60 m (Vaughan et al., 2013). According to satellite observations, the Antarctic Ice Sheet has lost 1350 Gt (gigatonnes) of ice between 1992 and 2011 (1 Gt = 1000 million tonnes), equivalent to an increase in sea level of 3.75 mm or 0.00375 m (Shepherd et al., 2012). 3.75 mm does not seem a lot but imagine that this sea-level rise is evenly spread over all the oceans on Earth, i.e. over a surface of about 360 million km², leading to a total volume of about 1350 km³, i.e. 1350 Gt of water… The loss over this period is mainly due to increased ice discharge into the ocean in two rapidly changing regions: West Antarctica and the Antarctic Peninsula (Figure 1, blue and orange curves respectively).

Figure 1: Cumulative ice mass changes (left axis) and equivalent sea-level contribution (right axis) of the different Antarctic regions based on different satellite observations (ERS-1/2, Envisat, ICESat, GRACE) from 1992 to 2011 (source: adapted from Fig. 5 of Shepherd et al., 2012 ) with addition of inset: Antarctic map showing the different regions ( source )

What are the projections for the future?

Figure 2: Ice velocity of the glaciers in the Amundsen Sea Embayment, West Antarctica, using ERS-1/2 radar data in winter 1996. The grounding line (boundary between ice sheet and ice shelf) is shown for 1992, 1994, 1996, 2000 and 2011 (source: Fig. 1 of Rignot et al., 2014 ).

Figure 2: Ice velocity of the glaciers in the Amundsen Sea Embayment, West Antarctica, using ERS-1/2 radar data in winter 1996. The grounding line (boundary between ice sheet and ice shelf) is shown for 1992, 1994, 1996, 2000 and 2011 (source: Fig. 1 of Rignot et al., 2014 ).

According to model projections from the Intergovernmental Panel on Climate Change (IPCC), global mean sea level will rise by 0.26 to 0.82 m during the twenty-first century (Church et al., 2013). The contribution from the Antarctic Ice Sheet in those projections will be about 0.05 m (or 50 mm) sea-level equivalent, i.e. 10% of the global projected sea-level rise, with other contributions coming from thermal expansion (40 %), glaciers (25 %), Greenland Ice Sheet (17 %) and land water storage (8 %).

The contribution from Antarctica compared to other contributions does not seem huge, however there is a high uncertainty coming from the possible instability of the West Antarctic Ice Sheet. According to theoretical (Weertman, 1974; Schoof, 2007) and recent modeling results (e.g. Favier et al., 2014; Joughin et al., 2014), this region could be subject to marine ice sheet instability (MISI), which could lead to considerable and rapid ice discharge from Antarctica. Satellite observations show that MISI may be under way in the Amundsen Sea Embayment (Rignot et al., 2014), where some of the fastest flowing glaciers on Earth are located, e.g. Pine Island and Thwaites glaciers (Figure 2). So what exactly is MISI?

What is marine ice sheet instability (MISI)?

 

Figure 3: Antarctic map of ice sheet (blue), ice shelves (orange) and islands/ice rises (green) based on satellite data (ICESat and MODIS). The grounding line is the separation between the ice sheet and the ice shelves. Units on X and Y axes are km (source: NASA ).

Figure 3: Antarctic map of ice sheet (blue), ice shelves (orange) and islands/ice rises (green) based on satellite data (ICESat and MODIS). The grounding line is the separation between the ice sheet and the ice shelves. Units on X and Y axes are km (source: NASA ).

To understand the concept of MISI, it is important to define both ‘marine ice sheet’ and ‘grounding line’:

 

  • A marine ice sheet is an ice sheet sitting on a bedrock that is below sea level, for example the West Antarctic Ice Sheet.
  • The grounding line is the boundary between the ice sheet, sitting on land, and the floating ice shelves (Figure 3 for a view from above and Figure 4 for a side view). The position and migration of this grounding line control the stability of a marine ice sheet.

 

 

The MISI hypothesis states that when the bedrock slopes down from the coast towards the interior of the marine ice sheet, which is the case in large parts of West Antarctica, the grounding line is not stable (in the absence of back forces provided by ice shelves, see next section for more details). To explain this concept, let us take the schematic example shown in Figure 4:

  1. The grounding line is initially located on a bedrock sill (Figure 4a). This position is stable: the ice flux at the grounding line, which is the amount of ice passing through the grounding line per unit time, matches the total upstream accumulation.
  2. A perturbation is applied at the grounding line, e.g. through the incursion of warm Circumpolar Deep Water (CDW, red arrow in Figure 4) below the ice shelf as observed in the Amundsen Sea Embayment.
  3. These warm waters lead to basal melting at the grounding line, ice-shelf thinning and glacier acceleration, resulting in an inland retreat of the grounding line.
  4. The grounding line is then located on a bedrock that slopes downward inland (Figure 4b), i.e. an unstable position where the ice column at the grounding line is thicker than previously (Figure 4a). The theory shows that ice flux at the grounding line is strongly dependent on ice thickness there (Weertman, 1974; Schoof, 2007), so a thicker ice leads to a higher ice flux.
  5. Then, the grounding line is forced to retreat since the ice flux at the grounding line is higher than the upstream accumulation.
  6. This is a positive feedback and the retreat only stops once a new stable position is reached (e.g. a bedrock high), where both ice flux at the grounding line and upstream accumulation match.
Figure 4: Schematic representation of the marine ice sheet instability (MISI) with (a) an initial stable grounding-line position and (b) an unstable grounding-line position after the incursion of warm Circumpolar Deep Water (CDW) below the ice shelf (source: Fig. 3 of Hanna et al., 2013 ).

Figure 4: Schematic representation of the marine ice sheet instability (MISI) with (a) an initial stable grounding-line position and (b) an unstable grounding-line position after the incursion of warm Circumpolar Deep Water (CDW) below the ice shelf (source: Fig. 3 of Hanna et al., 2013 ).

  • In summary, the MISI hypothesis describes the condition where a marine ice sheet is unstable due to being grounded below sea level on land that is sloping downward from the coast to the interior of the ice sheet.
  • This configuration leads to potential rapid retreat of the grounding line and speed up of ice flow from the interior of the continent into the oceans.

Is there evidence that MISI is happening right now?

 

Figure 5: Buttressing provided by Larsen C ice shelf, Antarctic Peninsula, based on a model simulation (Elmer/Ice). Buttressing values range between 0 (no buttressing) and 1 (high buttressing). The red contour shows the buttressing=0.3 isoline. Observed ice velocity is also shown (source: Fig. 2 of Fürst et al., 2016 ).

Figure 5: Buttressing provided by Larsen C ice shelf, Antarctic Peninsula, based on a model simulation (Elmer/Ice). Buttressing values range between 0 (no buttressing) and 1 (high buttressing). The red contour shows the buttressing=0.3 isoline. Observed ice velocity is also shown (source: Fig. 2 of Fürst et al., 2016 ).

In reality, the grounding line is often stabilized by an ice shelf that is laterally confined by side walls (see Figure 5, where Bawden and Gipps ice rises confine Larsen C ice shelf) or by an ice shelf that has a contact with a locally grounded feature (Figure 6). Both cases transmit a back force towards the ice sheet, the ‘buttressing effect’, which stabilizes the grounding line (Goldberg et al., 2009; Gudmundsson, 2013) even if the configuration is unstable, i.e. in the case of a grounding line located on a bedrock sloping down towards the interior (Figure 4b).

 

However, in the last two decades, the grounding lines of the glaciers in the Amundsen Sea Embayment (Pine Island and Thwaites glaciers for example) retreated with rates of 1 to 2 km per year, in regions of bedrock sloping down towards the ice sheet interior (Rignot et al., 2014). The trigger of these grounding-line retreats is the incursion of warm CDW penetrating deeply into cavities below the ice shelves (Jacobs et al., 2011), carrying important amounts of heat that melt the base of ice shelves (Figure 4). Increased basal melt rates have led to ice-shelf thinning, which has reduced the ice-shelf buttressing effect and increased ice discharge. All of this has led to grounding-line retreat. The exact cause of CDW changes is not clearly known but these incursions are probably linked to changes in local wind stress (Steig et al., 2012) rather than an actual warming of CDW.

 

 

Figure 6: Schematic representation of ice-shelf buttressing by a local pinning point (source: courtesy of R. Drews ).

Figure 6: Schematic representation of ice-shelf buttressing by a local pinning point (source: courtesy of R. Drews ).

There is currently no major obstacle to these grounding line retreats. Therefore, the Amundsen Sea Embayment is probably experiencing MISI and glaciers will continue to retreat if no stabilization is reached. This sector of West Antarctica contains enough ice to raise global sea level by 1.2 m.

 

What can we do about it?

MISI is probably ongoing in some parts of Antarctica and sea level could rise more than previously estimated if the grounding lines of the glaciers in the Amundsen Sea Embayment continue to retreat so fast. This could have catastrophic impacts on populations living close to the coasts, for example more frequent flooding of coastal cities, enhanced coastal erosion or changes in water quality.

Thus, it is important to continue monitoring the changes happening in Antarctica, and particularly in West Antarctica. This will allow us to better understand and project future sea-level rise from this region, as well as better adapt the cities of tomorrow.

Edited by Clara Burgard and Emma Smith


DavidDavid Docquier is a post-doctoral researcher at the Earth and Life Institute of Université catholique de Louvain (UCL) in Belgium. He works on the development of processed-based sea-ice metrics in order to improve the evaluation of global climate models (GCMs). His study is embedded within the EU Horizon 2020 PRIMAVERA project, which aims at developing a new generation of high-resolution GCMs to better represent the climate.

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 — Historical aerial imagery of Greenland

Image of the Week — Historical aerial imagery of Greenland

A few month ago, we were taking you on a trip back to Antarctic fieldwork 50 years ago, today we go back to Greenland during 1930s!

When geopolitics serves cryospheric sciences

The Permanent Court of International Justice in The Hague awarded Danish sovereignty over Greenland in 1933 and besides geopolitical interests, Denmark had a keen interest in searching for natural resources and new opportunities in this newly acquired colony. In the 1930s the Danish Government initiated three comprehensive expeditions; one of these, the systematic mapping of East Greenland, was set off by The Greenlandic Agency, The Marines’ air services, The Army’s Flight troops and Geodetic Institute. The Danish Marines provided pilots, mechanics, and three Heinkel seaplanes.

Danish expeditioner Lauge Koch, centre, along with his pilots all dressed in suits made from polar bear. (Credit: The Arctic Institute)

Danish expeditioner Lauge Koch, centre, along with his pilots all dressed in suits made from polar bear. (Credit: The Arctic Institute)

Aerial photography in the 1930s – practical constraints

The airplanes had three seats in an open cockpit. The pilot was seated in the front, the radio operator in the center and in the back the photographer – this seat was originally for the machine-gun operator.

At the outset, the idea was to take vertical images, but that was impossible at the time due to the height of the mountains and the limited capability of the aircraft to reach adequate heights. The airplanes couldn’t reach more than 4000 m – similar to the height of mountains in Greenland. Oblique images were therefore recorded. The reduced view of the terrain when photographing in oblique angles required many more flights than originally planned. The photographic films were processed immediately after each flight. 45,000 km were covered during the first season, which lasted about two and a half months. In the following years, each summer a flight covered parts of the Greenlandic coast. During the Second World War, the mapping was temporarily stopped due to safety reasons.

The aircraft had an open hole in the floor for the photographer, originally where the machine gunner would sit. (Credit: The Arctic Institute)

The aircraft had an open hole in the floor for the photographer, originally where the machine gunner would sit.(Credit: The Arctic Institute)

An unexplored treasure trove of climate data

The tremendous volume of aerial images obtained from several expeditions and hundreds of flights not only constitutes the cornerstone of mapping in Greenland, but is invaluable data for studying climate change in these remote regions. The 1930s survey, compared to modern imagery, provides crucial insight into coastal changes, ice sheet mass balances, and glacier movement. Glacier fluctuations in southeast Greenland have been identified, showing that many land-terminating glaciers underwent a more rapid retreat in the 1930s than in the 2000s, whereas marine-terminating glaciers retreat more rapidly during the recent warming (Bjørk et al, 2012).

An ongoing project between the University of Copenhagen, INSTAAR (Institute of Arctic and Alpine Research) in Boulder, Colorado, and Natural History Museum of Denmark is currently focusing on analysing deltaic changes in Central and Southern Greenland; linking shoreline development to climate changes – these historic aerial images are essential for detecting such coastal evolution. However, there are still many other links between the past and present climate to be discovered from these images. Interested in hearing more about the project or the aerial images? Please contact Mette Bendixen (mette.bendixen@ign.ku.dk)

Bibliography

Bjørk, A. A., Kjær, K. H., Korsgaard, N. J., Khan, S. A., Kjeldsen, K. K., Andresen, C. S., … & Funder, S. (2012). An aerial view of 80 years of climate-related glacier fluctuations in southeast Greenland. Nature Geoscience, 5(6), 427-432. http://dx.doi.org/DOI:10.1038/ngeo1481

Edited by Alistair McConnell, Sophie Berger and Emma Smith


Mette BendixenMette Bendixen is s a PhD student at the Center for Permafrost in Copenhagen. She investigates the changing geomorphology of Greenlandic coasts, where climate changes can have huge impact on the local environment.

Careers at the European Space Agency – How and Why?

Careers at the European Space Agency – How and Why?

As the pace of modern life speeds up and job competition becomes even more fierce, it is good to have a focused plan of where you would like to be in the future. The European Space Agency (ESA) offers traineeships and research positions to young scientists on a regular basis. They may be a springboard into your chosen career path, but how do you go about bagging one of these valuable opportunities? Below, two Research Fellows with ESA share their experiences of successfully arriving at their dream jobs. First, however, you might want to consider how you get the all-necessary experience in remote sensing in the first place. Fortunately, we are about to tell you just that: Apply for the ESA summer schools and training courses! Especially if you have a keen interest in all things icy, you should check out the upcoming ESA Advanced Training on Remote Sensing of the Cryosphere! More about this at the end.


Two (and a half) ways to join the European Space Agency as an early career Polar scientist

For most of scientists setting out on a career means completing a masters, getting a PhD, finding a post-doc. The attitude is that the jigsaw will just fall into place; perusing the job advertisements and hoping that somewhere out there, there will be that perfect project which you are not only extremely interested in, but moreover for which you tick all the right skills boxes. This simple approach may perhaps come to fruition but you stand a much greater chance if you actually draw up a plan early on in your career. The roadmap to success is knowing your goals and understanding your own limits.

One scientist with a plan is Anna Hogg. During her Geography degree at the University of Edinburgh, Anna discovered satellite data for monitoring the cryosphere. She realised she not only liked the subject but was rather good at solving computational challenges. Deciding to explore the technical side of remote sensing, Anna went on to do a masters in Space Studies at the International Space University in Strasbourg, France. After an internship with the German Space Agency (DLR) she started her PhD at the University of Leeds which she combined with an ESA Young Graduate Trainee position during her first year at graduate school.

Route 1: The ESA Young Graduate Traineeship (YGT)

If you have just finished your masters degree or even are a PhD student who has the flexibility to take up a one-year research secondment (N.B. subject to your University’s rules), you can apply to join ESA’s Young Graduate Traineeship programme. Like all jobs, Young Graduate Traineeship are advertised, but they pop up regularly and are a great way to get an insight into the mechanisms of the space agency and, in Anna’s case, its Earth Observation programme.

Anna Maria Trofaier, also an alumna of the University of Edinburgh, sidestepped into her career. After completing her physics degree, she returned to her hometown of Vienna, where she first came across Arctic issues. She had always been interested in Space, and had worked with satellites at an ESA summer school – albeit for planetary science. At this stage however, having enrolled  in a masters degree programme in Environmental Technology, she discovered satellite remote sensing for environmental monitoring. She contacted the Institute of Photogrammetry and Remote Sensing of the Vienna University of Technology, asking to join and work for them on an ESA project; a step that would shape her future for good. When she returned to the UK to do her PhD in Polar Studies at the University of Cambridge she made sure to keep the links to her Viennese colleagues and the project active. Working for ESA had always been her ambition; it was the realisation that this would have to happen through the Earth Observation programme that gave her the focus to acquire the appropriate skills for a job with ESA. And sure enough, when she was called for interview with the ESA Climate Office she felt she had arrived.

I really enjoyed my time working at ESA’s Earth Observation centre, ESRIN, just outside Rome. The Young Graduate Traineeship position I applied for had a large research component so I was able to design my own science project using data from the Earth Explorer satellite missions, like CryoSat-2. This was a great opportunity as it tied in really well with the PhD position I was awarded at the University of Leeds. There has been a lot of hard work (and fun!) along the way, but I am rewarded every day by working on an incredibly interesting topic with a network of great colleagues, (Anna Hogg).

Route 2: The ESA Internal Research Fellowship

The ESA Research Fellowship is a post-doctoral research programme that enables young scientists and engineers to undertake cutting-edge research outside of a university environment. Research Fellows usually propose their research topic within the framework of the advertised position. They are independent researchers, but they also contribute to their team’s activities. This way they get a glimpse of science management within ESA.

‘It’s been a fantastic experience! I’ve been given almost free hand to shape my own research, but it’s not just been me and my computer. I’ve thoroughly enjoyed being part of a team that coordinates research projects across Europe (the Climate Office’s main brief is the ESA Climate Change Initiative programme). I was also encouraged to get involved in the recent ESA GlobPermafrost project – working with some familiar faces but this time I’m on the ESA side of the project. We’ve been joking about how the tables have turned. It’s such a great feeling when colleagues become friends,’ (Anna Maria Trofaier).

Route 2.5: The ESA Living Planet Fellowship

There is another way to do research with ESA which is as a Living Planet Fellow (LPF). LPF’s are a traditional post-doctoral research associate (PDRA) at their own institutions, with the slight difference that part of their funding will come from ESA. Like ESA internal research fellows, LPF’s also have to propose an interesting 2 year research project, ideally with a link to other ESA science programmes. Having contributed to the ESA Climate Change Initiative (CCI) programme’s Ice Sheets project during her PhD, Anna Hogg is now a LPF at the University of Leeds. Her involvement in ESA CCI boosted her possibilities and enabled her to be successful in obtaining one of the much sought after Living Planet Fellowships.

So how will these stories help you find that perfect job (with ESA)?

  1. Keep checking the job openings. Certainly, the element of luck is always present – jobs need to be advertised in order for you to apply.
  1. Meanwhile, be outgoing and pro-active. To arrive at that ideal job you need experience. Apply for an internship or volunteer to work on a project where you will gain those all-important skills and make new contacts. And don’t underestimate the importance of networking – knowing people in your field and finding at least one person you can call a mentor will give you the support you need to successfully develop your scientific skills and securing that ideal position.
  1. Never give up. There might be times when you are uncertain whether you are fit to do the job – we all experience that nagging self-doubt. Just don’t give in to it!
  1. But do be self-aware. Of course you should always aim high and present yourself in the best light, but there is no point claiming you are good at something when in fact you have only peripherally come in contact with the subject. Understanding your limits will allow you to highlight all the things you are really good at, and if you realise you are lacking the necessary experience for the job, make sure you find a way to gain some.

Figuring out what it is you want to achieve in your professional life is half the battle. Tailoring your skills to be more in line with those goals will put you in the best position once that research or work opportunity comes along.

So what are you waiting for? Just go for it, apply and get those additional skills that will put you ahead of the game!

 

ESA Advanced Training on Remote Sensing of the Cryosphere

Thanks to our fantastic teaching team made up of experts from all over the world, we have put together an exciting course program covering thematic areas such as sea-ice, mountain glaciers, ice sheets and snow; and Earth Observation techniques such as altimetry, gravimetry and interferometry. The ESA course, which is co-sponsored by the UK Space Agency (UKSA) and UK Catapult centre, will take place at the Centre for Polar Observation and Modelling (CPOM) at the University of Leeds in September 2016. It already looks set to be a really interesting week, so if you have any questions about applying for a place on the course get in touch. Both Anna’s are on the organising committee and are happy to help.

Time series of Thwaites Glacier in West Antarctica. Credit: ESA.

Time series of Thwaites Glacier in West Antarctica composed of 29 image pairs from Sentinel-1. The top image shows the surface velocity in colours, and the bottom image is the velocity along a line starting at the grounding line and going inland. Get the data here . Credit: ESA.

(Edited by Nanna Karlsson, Sophie Berger and Emma Smith)

Image of the Week — Last Glacial Maximum in Europe

Image of the Week — Last Glacial Maximum in Europe

During the last ice age*, ~70,000 to 20,000 years ago, the climate was much colder in Europe.

As a result, the northern part of Europe was fully covered by the Fennoscandian (a.k.a the Scandinavian ) ice sheet, which extended up to the British Isles and some parts of Poland and Germany. In central Europe, the Alps were also almost fully glaciated.

The storage of all this ice on the continent lowered the sea level (seedark green), which substantially reduced the extent of the North Sea.

*This period is referred to as the Weichselian glaciation and the Würm glaciation in Northern Europe and the Alps, respectively.

 

More information

A more complete and accurate dataset (including GIS maps) of Europe during the last glacial maximum is freely available :

Becker, D., Verheul, J., Zickel, M., Willmes, C. (2015): LGM paleoenvironment of Europe – Map. CRC806-Database, DOI: http://dx.doi.org/10.5880/SFB806.15

LGM_Europe_Map_v1

 

Image of the Week – Changes in the Greenland Ice Sheet Documented by Satellite

Image of the Week – Changes in the Greenland Ice Sheet Documented by Satellite

Monitoring the changing ice mass of the Greenland Ice Sheet provides valuable information about how the ice sheet is responding to changing climate, but how do we make these measurements over such a large area of ice? Using NASA’s GRACE satellites (twin-satellites flying in formation) it is possible to make detailed measurements of the Earth’s gravitational field. As ice is gained/lost from the ice sheet the local gravitational field will change. This will cause the distance between the two GRACE satellites to change by a small amount as they pass over the ice sheet and by measuring the changing distance between the two satellites with very high precision, the change in ice mass can be determined.

The image above shows the change in mass of the Greenland Ice Sheet between January 2004 and June 2014 (updated from Luthcke et al., 2013). The colours indicate the change in mass in units of water height equivalent ranging from -250 to +250 centimetres, with blue indicating a mass gain and red areas a mass loss. The graph overlay shows the total accumulated change in gigatons over the ten year period.  A video animation of the changes over time can be seen using the NASA scientific visualisation studio:

Converting changes in the measured gravitational field to ice mass is a complex process and other factors contributing towards the change in gravitational field must be accounted for. One major factor is glacial isostatic adjustment (Earth’s mass redistribution in response to historical ice loading). To learn more about how glacial isostatic adjustment is accounted for to extract the ice mass change signal see Peltier et al. 2015.

Image of the Week — Greenland ice sheet and clouds

Image of the Week — Greenland ice sheet and clouds

A new study combining satellite observations and model simulations shows that clouds increase meltwater runoff in Greenland by one-third compared to a cloud-free scenario.

Precipitation effects not considered, clouds above the Greenland ice sheet reduce its Surface Mass Balance (SMB) [red in figure] compared to clear-sky conditions [blue in figure]. Because clouds trap the outgoing radiation from the ice-sheet surface, they locally warm the atmosphere below, which reduces Greenland’s meltwater refreezing at night. Hence, clouds increase runoff from the ice sheet by 56 billion tons of water each year.

Reference/further reading:

  • Van Tricht, K., S. Lhermitte, J. T. M. Lenaerts, I. V. Gorodetskaya, T. S. L’Ecuyer, B. Noël, M. R. van den Broeke, D. D. Turner, and N. P. M. van Lipzig. 2016. “Clouds Enhance Greenland Ice Sheet Meltwater Runoff.” Nature Communications 7 (January). Nature Publishing Group: 10266. doi:10.1038/ncomms10266.
  • Article in the Washington Post about the paper.
  • You can follow Kristof Van Tricht the study’s lead author on twitter @kristofvt.

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 — Ice Sheets and Sea Level Rise (from IPCC)

Image of the Week — Ice Sheets and Sea Level Rise (from IPCC)

Context

On the eve of the COP21, it is of paramount importance to recall how strongly the cryosphere is affected by Climate Change. Today, we present the impact of melting ice on sea level rise, as it is presented in the latest assessment report of the Intergovernmental Panel on Climate Change.

Quick facts

-Since 1992, the Glaciers, Greenland and Antarctic Ice Sheets have risen the sea level by 14, 8 and 6 mm, respectively.
-The Greenland and Antarctic ice losses have accelerated for the last 2 decades.
In Greenland ice-loss rates increased from 34 Gt/yr* (between 1992-2001) to 215 Gt/yr (between 2002-2011), which was caused by more widespread surface melt + run-off and enhanced discharge of outlet glaciers.
While in Antarctica, ice-loss rates “only” rose from  30 Gt/yr (between 1992-2001) to 147 Gt/yr (between 2002-2011), this loss mostly occurred in West Antarctica (Amundsen Sea Sector and Antarctic Peninsula) and  was driven by  the acceleration of outlet glaciers.

 

*An ice loss of 100 Gt/yr is approximately 0.28 mm/yr of sea level equivalent

Further Reading [Read More]