Sophie Berger is a PhD student of the glaciology unit, at the Université Libre de Bruxelles (ULB), Brussels Belgium. She is using various remote sensing data and techniques to investigate the dynamics and stability of the ice shelves in Dronning Maud Land (East Antarctica).
She tweets as @SoBrgr.
(Upper) Distribution of ice loss determined from Gravity Recovery and Climate Experiment (GRACE) time-variable gravity for (a) Antarctica and (b) Greenland, shown
in centimetres of water per year (cm of water yr –1 ) for the period 2003–2012. (Lower) The assessment of the total loss of ice from glaciers and ice sheets in terms of mass (Gt) and
sea level equivalent (mm). The contribution from glaciers excludes those on the periphery of the ice sheets. (Credit: IPCC (2013), Assessment Report 5, Working Group I, Technical Summary , Figure TS.3, p41)
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.
-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
Two polarimetric SAR images Artctic Sea Ice. The colours reflect the different polarimetric channels of the SAR (red = VV, green = HV and blue = HH). Credit: Jakob Grahn.
This illustration shows two Synthetic Aperture Radar (SAR) images taken over sea ice in the Arctic Ocean. Both images are polarimetric and the different colours reflect the different polarimetric channels of the SAR (red = VV, green = HV and blue = HH).
The two images are from the two satellites “ALOS-2” and “RADARSAT-2”. These are equipped with radars that operate at wavelengths around 24 cm and 6 cm, respectively. As can be seen, certain types of sea ice appear very different due to this difference in radar wavelength. In particular, leads in the ice, that is, open or refrozen cracks, appear very red for the longer wavelength, but dark for the shorter wavelength. A full understanding of what causes these differences is still not complete, but could help monitor ice properties, such as thickness and salinity, with satellites. These properties are in turn crucial for climate scientists.
Click on the image to see difference between the two images. (Credit: J. Grahn)
Three repeat photos of the Muir Glacier, Alaska taken on 13 August 1941, 4 August 1950 and 31 August 2004 . Credit: U.S. Geological Survey
The Muir is a valley glacier (Alaska) that has significantly retreated over the last 2 centuries. The 3 pictures have the same field of view and record the changes that occurred during the 63 years separating 1941 and 2004.
In the 1941, the terminus of the glacier is on the lower right corner of the photo. The Muir is then a tidewater glacier up to 700m thick and is well connected to its tributary, the Riggs Glacier (upper right part of the photo).
9 years later, in 1950, the Muir Glacier has retreated by more than 3 km, is more than 100m thinner but is still connected to Riggs Glacier.
By 2004, the Muir glacier has retreated further inland and its terminus is no longer visible on the picture. The Riggs glacier is now disconnected to the Muir and has retreated by 0.25km. Vegetation has invaded the place.
The photo comes from and the text is inspired from the section “Repeat photography of the Alaskan Glaciers” on U.S. Geological Survey website. Photo 1: W. O. Field, # 41-64, courtesy of the National Snow and Ice Data Center and Glacier Bay National Park and Preserve Archive. Photo 2 : W. O. Field, # F50-R29, courtesy of the Glacier Bay National Park and Preserve Archive. Photo 3: B. F. Molnia, USGS Photograph
Thickness of the Antarctic ice shelves. Credit: M. Depoorter
Thickness of floating ice shelves in Antarctica. Ice thickness is greatest close to the grounding line where it can reach 1000 meters or more (red). Away from the grounding line, the ice rapidly thins to reach a few hundreds of meters at the calving front. Ice thickness varies greatly from one ice shelf to another. Within ice shelves, “streams of ice” can be spotted originating from individual tributary glaciers and ice streams.
This dataset was used to compute calving fluxes and basal melt rates of Antarctic ice shelves (see Depoorter et al, 2013). This ice thickness map was derived from altimetry data (ERS and ICESat) acquired between 1994 and 2009 and corrected for elevation changes during this period.
The SAFIRE team sets up the drilling device on the Store Glacier, Western Greenland. Credit : T.J. Young
How do you get a hot water drill onto an ice sheet? The Subglacial Access and Fast Ice Research Experiment (SAFIRE) uses a hot water drill to directly access and observe the physical and geothermal properties where the ice meets rock or sediment at the glacier-bed interface. Here, SAFIRE principal investigator Bryn Hubbard and post-doc Sam Doyle help fly in the drill spool at the start of the Summer 2014 field campaign on Store Glacier, Western Greenland. Three boreholes were successfully drilled and instrumented with thermistors, tilt sensors through the ice column, and subglacial water pressure, electrical conductivity, and turbidity sensors at the ice-bed interface. Further work will be carried out in Summer 2016, when more instruments will be installed at the study site, and more helicopter slinging will be needed.
Deglaciation and formation of an ice rise with the ice-sheet model BISICLES. The simulation starts with an ice sheet in steady state that overrides a topographic high in the bed, close to the calving front. The sea level is then forced to rise steadily with 1 cm per year during 15 thousand years, and the simulation goes on until the ice sheet reaches steady state.
The animation below shows that the formation of an ice rise delays the grounding line retreat.
The movie shows the ice sheet retreat and the ice rise formation and evolution in between the two steady states. The movie starts after 5 thousands years of sea level rise. The ice upper surface is colored as a function of the velocity magnitude. The ice lower surface is colored either in light gray for floating ice or dark gray for grounded ice. Credit: L. Favier.
What do polar bears and emperor penguins have to do with the Eiffel Tower and Notre Dame? Pole to Paris has the answer.
Erlend, the Northern runner, in the Norwegian mountains. (credit : Varegg Fleridrett.)
Erlend Moster Knudsen earned his PhD in climate dynamics after four years of research from the University of Bergen, Colorado State University and University of Alaska Fairbanks on Arctic sea ice and its interaction with atmospheric circulation. He took some time to answer a few questions about the project he started with Daniel Price, a fellow polar climate researcher and PhD in Antarctic sea ice . The project is called Pole to Paris.
What is Pole to Paris?
Pole to Paris is a climate awareness campaign and outreach project ahead of the 21st Conference of the Parties (COP21) in Paris this year. This December in Paris, the United Nations will meet to negotiate a “climate deal” to pave the way toward a global carbon free future by reducing anthropogenic greenhouse gas emissions. If we plan to curb our emissions, it is of paramount importance that a consensus is reached under COP21.
The aim of Pole to Paris is to raise the understanding on climate changes in general and the importance of COP21 in particular. The campaign follows two journeys from the poles to Paris – by bike and running shoes.
Map roughly showing the route of the 17,000 km-long Southern Cycle and 3000 km-long Northern Run (credit: Pole To Paris)
Could you tell us a bit more about these biking and running journeys?
The 17,000 km Southern Cycle has gotten off to a good start. Carrying with him a flag from the Antarctic continent, Daniel has already biked across Australia and Indonesia, and is now biking through Malaysia. His next stops will be Thailand, Bangladesh and China, where he will spend weeks documenting stories on sea level rise, glacial melt and pollution.
Later this year, I will start the 3000 km-long Northern Run from Tromsø, running with a flag from the North Pole. After 2000 km through Norway, I will team up with other environmental scientists from Edinburgh to bring the flag to Paris. There we will meet up with the cyclists from the south.
What drives you, a PhD in sea ice, to put on your running shoes and run across Europe?
As we were going toward the end of our PhDs, Daniel (Pole to Paris director) and I (Pole to Paris deputy director) realized more and more that people generally are unaware of the clear results of climate science. There is a large gap in the understanding between academia and the general public. We want to bridge this gap by doing something as crazy as biking and running across half of the globe to raise awareness of climate change, document climate change and bring personal stories of climate change from the corners of the world to COP21.
Running and biking, we interact with people who we meet and who join us along the way, we give school presentations and take part in open climate events. As biking and running climate scientists, we are closer to the group of people science should serve: the general public.
Why are you starting from the Poles?
Pole to Paris friend Seamus Donaghue at the North Pole. On an expedition there, Seamus and his team mate Eric Philips brought the Pole to Paris flag to the northernmost point for his scientific colleagues of Pole to Paris. Erlend will bring this flag on from Tromsø. (credit: Eric Philips)
The starting points of the two routes are chosen deliberately. Being arguably the regions with the fastest signs of climate change, the Antarctic and the Arctic are changing in front of our eyes. Not that many of us go to the two poles. But the ones who do repeatedly are overwhelmed with unprecedented facts.
My friend Will Steger is one of them. Having been the first to reach the North Pole by dogsled unsupported and the first to cross the whole Antarctic continent by dogsled with an international team of five in the late 80’s and early 90’s, his team of explorers were the first also to cross the Arctic Ocean by dogsled in 1995. More than that, they are most likely the last ones to have done so, due to rapid sea-ice melt.
The melting of the Arctic sea ice is indeed alarming. The Arctic Ocean is loosing its lid – fast. In addition to the enhanced heat fluxes into the cooler atmosphere in most of the year, the ice-albedo, lapse-rate and Planck feedbacks each accelerate the warming in positive feedback mechanisms. Additionally, a melting Arctic also causes changes in the oceanic and atmospheric circulations, with alterations in poleward transports of heat and moisture.
The interaction between atmospheric circulation and the melting Greenland ice sheet and Arctic sea ice was the topic of my PhD. Associated with these melts, we found high-latitude storminess to decrease in summer (Knudsen et al. 2015). Instead, cyclones generally tracked more zonally, giving wetter, cooler and stormier summers in north-western Europe and around the Sea of Okhotsk. Coincidentally, unusually warm conditions have prevailed in a wide region from the Mediterranean to East Asia during summer months of anomalous high Arctic sea ice melt. These are areas of already high temperatures climatologically.
A stronger link between Arctic sea ice melt and mid-latitude extreme weather was first put forward by Francis and Vavrus (2012). They linked the Arctic amplification (the enhanced warming in the Arctic compared to the average warming across the globe) to a wavier the jet stream, where more stationary weather systems increase the risk of extreme weather conditions in midlatitudes. Since then, the theory has been and is still heavily discussed within the scientific community. Nevertheless, if their hypothesis should hold, a large fraction of the global population would need to reconsider the Arctic climate changes as too distant to reflect upon.
Of course, an even more alarming scenario is if the entire Antarctic ice sheet and the Greenland ice sheet were to melt completely. This would result in a sea level rise of over 60m. This will probably not happen within our lifetime, but enough ice has already melted to cause severe troubles for many Pacific Islands.
(credit: Pole to Paris)
How do you plan to do climate outreach along the two journeys?
Along the routes, we document climate changes and personal stories of environmental changes seen throughout their lifetime, but also the positive means by which action toward a more sustainable future is made. We give school and community presentations, arrange open climate events and unite people across a wide range of backgrounds. We speak up about climate change, knowing that we must work hard to stay objective in a politicized world.
How is your experience with Pole to Paris so far?
From left to right: Oria Jamar de Bolsée (EU and Indonesia coordinator in Pole to Paris), Beate Trankmann (head of UNDP Indonesia), Daniel Price (director of Pole to Paris), Toto Sugito (leader of Bike to Work Indonesia) and Erlend Moster Knudsen (deputy director of Pole to Paris) from car-free Sunday in Jakarta, Indonesia (credit: UNDP Indonesia)
Pole to Paris has gotten off to a really good start. We got a lot of attention on Indonesia, a key country for bridging the demands of developing and developed countries under COP21 negotiations. There, Daniel (the cyclist), Oria Jamar de Bolsée (EU and Indonesia coordinator) and I (the main runner) worked to raise the awareness of climate changes. This brought us from rural places to megacities, from preschools to high schools and talking with people from farmers to ministers. It has been very engaging.
While climate change is something distant for many of my fellow Norwegians, many Indonesians depend on the land and its resources. While human activities, such as deforestation, overfishing or lack of waste management, are the main source for this environmental degradation, climate change is also appearing in front of their eyes.
So perhaps it is not that far from the Arctic and the Antarctic to Indonesia after all? The Polar Regions are indeed shaping the coast of the archipelago, through sea level rise and erosion.
What do you expect from Paris and COP21?
The French capital is the arena for the most important climate summit this far – COP21. Pole to Paris is using bike, running shoes and our background in environmental sciences to raise awareness about the importance of this meeting.
While there, we will work with partners to arrange open events and share stories from all the corners of the world we have biked or run through. The stories of the farmers and the fishermen, the stories of the Antarctic and Arctic – all are important to remember when our global leaders will make their decision this December.
To conclude is there something you would like to say to your fellow environmental scientists?
In my mind, funded by society, scientists have a responsibility to speak up about our research. Research on climate change is too vital and pressing to keep within academia.
As environmental scientists, we have the knowledge and the tools. One of the latter is our voice. We want to hear yours too.
A typical iSTAR field camp with the living ‘caboose’ on the left (credit: Damon Davies).
It’s the 2nd December 2013 and I find myself in one of those rare occasions in life where I feel I need to pinch myself to see if I’m dreaming. Why? Somehow I’m in control of a British Antarctic Survey De Havilland Twin Otter aircraft flying over the white featureless expanse of the West Antarctic Ice Sheet. I’m part of a team of 12 heading to Pine Island Glacier, a remote ice stream 75°S and around 1500 km from Rothera Research Station on the Antarctic Peninsula.
The journey so far has taken four flights from London to Punta Arenas on the Southern tip of Chile and across the Drake Passage to Earth’s southernmost continent. Our pilot, John is having some lunch and keeping a close eye on my erratic attempts to hold a constant bearing and altitude as I ‘co-pilot’ the final leg of our journey. On the horizon I spot a thin strip of bright white snow that marks the groomed ski-way of our landing site.
John takes back the controls and eases the throttle down for a perfectly smooth landing. I step down from the plane with a familiar squeak and crunch of cold dry snow underfoot in an unfamiliar environment like nothing I’ve experienced before. I squint as my eyes adjust to the bright white desert of flat ice sharply contrasted by a crystal clear blue sky spanning the distant horizon in every direction. This will be my home for the next few months as I embark on my first Antarctic field season as part of the first iSTAR science traverse of Pine Island Glacier.
The iSTAR research programme
iSTAR (ice sheet stability and research programme) is a £7.4 million research programme funded by the UK Natural Environment Research Council (NERC) involving 11 UK universities and the British Antarctic Survey (BAS). Its aim is to improve understanding of ice-ocean interaction and ice dynamic response of Amundsen Sea sector of the West Antarctic.
Over the past few decades this region has been undergoing the greatest rates of ice loss on the planet causing concern over its potential future contribution to rising global sea-level. Pine Island Glacier (PIG) drains around 10% of the West Antarctic Ice sheet (WAIS) which contains enough ice if melted to raise global sea-level by approximately 3.3 metres.
In order to make accurate predictions about how this region will respond to environmental change requires good physical observations and measurements. Throughscientific ocean cruisesand an over-ice traverse spanning two field seasons combined with satellite remote sensing and numerical modelling, iSTAR aims to provide the data necessary to improve the accuracy of projections for the contribution of the WAIS to future sea level.
The iSTAR traverse of Pine Island Glacier
Traditionally the UK has conducted glaciological investigations in remote regions of Antarctica using small field units typically consisting of one scientist and a field assistant. For larger drilling projects equipment has to be flown by aircraft at great expense and fuel consumption.
For iSTAR, a new approach was undertaken using two ‘tractor trains’. These consist of two Pisten Bully snow tractors towing two long poly sleds with fuel bladders and three metal cargo sledges including a living ‘caboose’; a converted shipping container with a cooking and living space (essentially a caravan fit for polar travel!). All this equipment was delivered by the RRS Ernest Shackleton to the Abbot Ice Shelf in February 2012 and driven to Pine Island Glacier ready for the first traverse the following season.
iSTAR tractor train (credit: Alex Taylor).
This infrastructure provided a means to meet the ambitious science aims of the iSTAR traverse making it possible to collect more ground measurements over a wider area than ever previously possible and with greater fuel efficiency.
The traverse follows a 900 km route visiting the trunks and tributaries of PIG to conduct a range of measurements on the ice.
The route of the iSTAR traverse of Pine Island Glacier, West Antarctica (credit: www.istar.ac.uk).
So what about the science?
The iSTAR programme is split into four science projects, with iSTAR A and B making measurements from scientific ships and iSTAR C and D collecting data during the overland traverse of Pine Island Glacier. It is the overland traverse that we were involved in.
iSTAR C: Dynamic Ice project:
This project aims to understand the internal dynamic processes responsible for transmitting the effect of thinning of PIG’s floating ice shelf caused by melting of warm ocean currents upstream into the trunk and tributaries of the ice stream. Of particular interest is how the underlying geology of the ice influences its flow.
Over the course of two field seasons the traverse collected over 2000 km of radar data and over 40 km of seismic surveys were completed. The team used skidoos to tow radar equipment across the ice making the most of the 24 hours of daylight of the Antarctic Summer to provide detailed images of the ice thickness and bed topography. The geology of the subsurface was also investigated by analysing the seismic energy returned from small explosive charges buried in the surface of the ice.
Operating the ice penetrating radar (left) and firing explosives for seismic surveys (right) (credit: Damon Davies).
iSTAR D: Ice Loss project
Satellite measurements over the past two decades have revealed rapid thinning (up to 1.5 metres per year) and acceleration of PIG’s ice flow. The iSTAR D project aims to take measurements to extend the record of past snow accumulation and ice density to improve estimates of ice loss that cannot be determined from satellite measurements.
To determine past accumulation and understand surface processes such as snow density changes and compaction, we drilled 10 shallow (50 metre) ice cores. These ice cores had to be kept frozen and shipped back to the UK where their chemistry is being analysed to enable us to quantify how much snow has fallen onto the ice sheet in the past. Over 20 snow density profiles were recorded using a device called a ‘Neutron Probe’ which uses a radioactive source to measure neutron scattering from within the snowpack to calculate ice density. This might sound dangerous but to my disappointment after spending many hours operating this equipment I have yet to develop super powers!
Rob, Becky and Emma inside the ice core drilling tent (left), Damon and Andy working at a Neutron Probe site (right) (credit: Alex Taylor).
Surface radars operating at the same frequency as satellites that orbit the earth measuring ice surface changes were also deployed. These ground radar measurements enable us to improve the accuracy of satellite derived estimations of ice volume loss from West Antarctica.
Anna operating the surface radar (credit: Jan De Rydt).
Now you know all about iSTAR science but what’s it like to live and work in one of the most remote regions of the coldest, highest, driest and windiest continent on Earth?
Life in the field
Life on the iSTAR traverse is perhaps similar to a travelling circus, only instead of jugglers and gymnasts we have scientists and mechanics and rather than a ‘Big Top’ we had the ice core drilling tent. At each of the 22 sites on the traverse route the circus would set up camp for a few days to a week. Tents would be pitched, sledges un-hitched and science equipment unloaded, the whole process of setting up camp taking just an hour or two.
Setting up the drilling tent (left). iSTAR accommodation (right) (credit: Alex Taylor).
This region of Antarctica has a reputation for wild weather. Temperatures can drop below -30°C and winds can reach hurricane speeds reducing visibility to within a few metres. However, on calm days it can be so silent you can hear your own heartbeat and the strength of the summer sun provides welcome warmth. Good weather means working long hours as you never know how long it might last. When the weather takes a turn for the worse, all you can do is shelter from the elements and wait patiently for the storm to pass, though patience can be tested when the storm lasts for a week!
iSTAR team members battling a storm (left) (credit: Alex Taylor). Tent damage after a big storm (right) (credit: Damon Davies).
The living ‘caboose’ offers a warm shelter away from the elements. This is also where the team gathers at meal times with everyone taking turns to cook for the rest of the group. The iSTAR menu normally consists of a porridge breakfast, soup and bread for lunch, some form of carbohydrate with meat slop for dinner followed by tinned fruit/pudding with powdered custard for dessert. The labels of some meal packages such as ‘chicken own juice’ and ‘sausages in lard’ aren’t particularly enticing but generally the food is good by Antarctic field standards.
Dinner-time in the caboose (left) (credit: Alex Taylor). James finishing off a cottage pie with a blow torch (right) (credit: Damon Davies).
The iSTAR traverse was an incredible experience that allowed me to learn a range of data acquisition techniques as well as learning how to work in the often hostile Antarctic weather. I was one of 9 PhD students and post-doctoral researchers involved in the traverse seasons who were able to work alongside highly experienced scientists in the field. Our success is a testament to the hard work and good spirit of everyone involved.
Left photo, 2013/14 traverse participants. Left to right, Anna Hogg (Leeds), Rob Bingham (Edinburgh), Andy Smith (BAS), Damon Davies (Edinburgh), Johnny Yates (back row, BAS), Tim Gee (middle, BAS), Jan De Rydt (front, BAS), Steph Cornford (Bristol), James Wake (BAS), Peter Lambert (Reading), Thomas Flament (front, Leeds), David Vaughan (BAS) (credit: David Vaughan). Right photo, 2014/15 traverse participants. Left to Right, James Wake (BAS), Mark Baird (BAS), Tim Gee (BAS), Emma Smith (BAS), Isabelle Nias (Bristol), Robert Mulvaney (BAS), Andy Smith (BAS), Alex Brisbourne (back row, BAS), Rebecca Tuckwell (middle, BAS), Alex Taylor (front, BAS), Sebastian Rosier (BAS), Damon Davies (Edinburgh) (credit: Alex Taylor).
For more information about the iSTAR research programme visit www.istar.ac.uk and the ‘stories from the field’ blog posts to read more tales from traverse fieldwork.
Acknowledgments: A huge thanks to James Wake, Tim Gee, Johnny Yates, Mark Baird and Alex Taylor for their tireless support in the field. The traverse could not have succeeded without support from the staff at Rothera Research Station. Also thanks to Emma Smith for helpful comments on this blog.
Damon Davies is a PhD researcher at the University of Edinburgh, School of Geosciences Glaciology and Cryosphere research group. His research uses geophysics to investigate the dynamics of ice stream beds and their control on ice stream flow.
19 November 2014, the Iliuchine 76 gently lands on the runway of the Russian Antarctic station, Novolazarevskaya, in Dronning Maud Land. For the first time, I’m in Antarctica! It is 4 o’clock in the morning and we need to hurriedly offload 2 tons of material intended for our field mission near the Belgian Princess Elisabeth Station. I’m deeply impressed by the landscape although it is dotted with containers, people and machines. I am impressed by the fuzz. I am impressed by the novelty. I am impressed by the icescape. It is cold, but I don’t feel it.
(Credit B. Van Liefferinge)
I take part in an expedition lasting five weeks and led by the Laboratoire de Glaciologie of the Université Libre de Bruxelles (ULB) in the framework of the Icecon project.The project aims at constraining past and current mass changes of the Antarctic ice sheet in the coastal area of Dronning Maud Land (East Antarctica) to better understand past and present ice volumes and the extension of the Antarctic ice sheet across the continental shelf during the last glacial period. This year we are a team of 5 to do the job: GPS measurements, ice-core drilling, high- and low-frequency radar measurements (GSSI and ApRES), televiewer measurements … The ApRES radar is a new phase-sensitive radar developed by British Antarctic Survey (BAS), capable of detecting internal structures in the ice and changes in the position of internal layering over time.
After a couple of hours at the Russian base, it’s time to fly to the Princess Elisabeth Station (the Belgium base, PEA). The arrival in a Bassler (a former DC3 re-equipped with turbo-props) with stunning views of the Sor Rondane Mountains and the Princess Elisabeth station on the Utsteinen rim is simply magnificent. Alain Hubert, the base manager, gives us the first security rules and shows us the different parts of the base.
(Credit B. Van Liefferinge)
After following the various field training and especially an exercise that aims at pulling yourself out of crevasses, it’s time to inspect, to set up, and to test our equipment. While one part of the team sets up the drill, Frank Pattyn and I test the GPS and radar equipment, mainly the ApRES that is a new “toy” for us. The first results are promising, we can clearly identify the bed topography and internal layers. The two GPS systems sponsored by the “10km of the ULB”, a run organised by the students of our Faculty, are also tested next to the L1L2 GPS systems for precise positioning. As our departure is imminent, I’m excited (even though my level of Coca-cola are getting low – I ‘m an avid consumer of this “evil drink” and Frank was afraid that I wouldn’t survive without sufficient sugar intake).
(Credit B. Van Liefferinge)
On 27 November, we leave PEA in the evening for one night and one day across the Roi Baudouin Ice Shelf to Derwael ice rise. We are 6 scientists, 2 field guides and 1 technician. After 25 hours of travel, we set up the camp on the top of the divide. We start immediately with the radar measurements to locate potential drill sites. However, we get caught in a storm the following day and as Frank says “not a nice one”.
(Credit F. Pattyn and B. Van Liefferinge)
The snow drift is just amazing and the atmospheric pressure drops frighteningly (“can this still go lower?”). The whiteboard installed in the living container is not wide enough to draw the graph of pressure change, nor is it high enough to accommodate the lowest values. Furthermore, it’s quite warm, meaning that snow melts in contact with persons and goods. Despite efforts of everyone to clear away the snow, we leave our tents and sleep in the containers for 2 days. Not the most comfortable nights, because we share a two-bunk space with three people, and despite a container it remains very shaky! After three days of amazing experience, we clean up the camp and the science restarts. For one week Frank and I perform radar and GPS measurements in a 10km radius around the camp. These measurements will be repeated in 2015-2016 to provide new data on ice compaction, density and flow. While Frank thoroughly checks the collected data, I have some time to get familiar with the drill, which should prove to be very useful thereafter. The “drill part” led by Jean-Louis Tison and Morgane Philippe aims at drilling two 30 m deep ice cores on Derwael Ice Rise, 2 km on each side of the divide. We want to investigate the spatial variability of snow accumulation induced by this ice rise that sticks approximately 300 m above the surrounding flat ice shelf and therefore perturbs the surface mass balance distribution (Lenaerts et al., 2014).
(Credit F. Pattyn and B. Van Liefferinge)
I use this week to improve my knowledge on other scientific techniques, such as the coffee-can method (will complement the results from the ApRES) or geodetic GPS measurements with Nicolas Bergeot. I also learn the basics of snowmobile mechanics (it’s surprising to see the amount of snow that can be put in an engine!). Unfortunately we get stuck for another 2 days by a new storm event. We use this time to have a look on the first radar profiles and to prepare the second part of the expedition.
On 9 December, we leave the camp on Derwael ice rise and move towards the Roi Baudouin Ice Shelf, 40km to the west. We set up the camp in a longitudinal depression (like a trench) on the ice shelf that stretches from the grounding line to the coast.
The purpose of this part of the field work is twofold: first of all, determine the mass budget of ice shelves. To do that, we need to map carefully the flow speed of the ice-shelf. Secondly, understand the formation of the trench in evaluating if under the ice-shelf, the ice is melting or accreting (formation of marine ice) and analyze the surface melt history by investigating near-surface melt layers.
The first three days are devoted to make radar measurements (ApRES) in the center and on the sides of the trench. The thickness of ice and the reflection at the interface with the ocean is different from the one on the ice rise; we take some time to develop a robust method and determine the best settings of the radar. Together with Frank Pattyn and Jan Lenaerts (InBev Baillet Latour fellowship, http://benemelt.blogspot.be/) I perform a 120km transect with a high-frequency radar towed by a snowmobile to map the near-surface internal structure along the ice shelf and link the drill site with the grounding zone. Driving at 8 km per hour for 8 hours a day, it’s an opportunity for me to think about how lucky I am to be here. Alone in the vastness of the Roi Baudouin ice-shelf, I feel very small. Back in camp, we find out that the drill got stuck at a depth of 54m in the borehole and preparations to free the drill are on their way. During this time I carry out a number of high-frequency radar measurements with Alain Hubert (the base manager) to fine-tune the equipment to potentially detect crevasses near the surface. To our surprise, we stumble upon a crevasse more than 500m long, 10m wide and 20m high. Moreover, we can safely descend through the apex of the crevasse to discover its vastness. Truly a magic moment!
(Credit A. Hubert)
Thirty-six hours later, and thanks to antifreeze, the drill restarts. This small technical incident pushes us to work the next couple of days through the day and the night (under the sun at 3am is rather special) and we take turns in operating the drill. We reach a depth of 107m, not far from the 155 meters needed to reach the bottom of the ice shelf, but the brittle ice makes progress very difficult. Nevertheless, this is the third core of the (short) season, and as valuable as the previous ones. We can clearly identify every single ice layer over 200 years as well as the surface melting history.
(Credit A. Hubert)
Before leaving back to the base, we finish the installation of the famous Tweetin’IceShelf project (http://tweetiniceshelf.blogspot.com); a project also presented at the EGU General Assembly in 2015. We deploy two GPSes on the flanks of the trench and one in the center. These are simple GPS systems that record their position every hour. They are named GPS CGEO (from Cercle de Géographie et de Géologie de l’ULB) and GPS CdS (from Cercle des Sciences). In the center of the trench, the ApRES is installed which measures once a day the radar signal through the ice. All systems will be effective throughout the Antarctic winter. Data are sent via Twitter to be followed by a larger community. Just follow the @TweetinIceShelf on Twitter. You will not be disappointed.
(Credit F. Pattyn)
It’s time to go back to the station, which is reached after 20 hours of travel across the ice shelf and the coastal ice sheet. Over 2 days we will be at Cape Town and we have to clean up everything for the next field season.
(Credit N. Bergeot)
I know it is my first time to Antarctica, and as most first-timers, an unforgettable experience of vastness, whiteness, silence, laughter, hard work and fun. When I board the plane I feel delighted and fulfilled and ready to find back green landscapes and city soundscapes in less than ten hours.
Brice Van Liefferinge is a PhD student and a teaching assistant at the Laboratoire de Glaciology, Universite Libre de Bruxelles, Belgium. His research focuses on the basal conditions of the ice sheets.