Sea-ice brine sampling is sometimes challenging [Credit: Stefan Hendricks]
Sea ice brine sampling is always great fun, but sometimes somewhat challenging !
As sea water freezes to form sea ice, salts in the water are rejected from the ice and concentrate in pockets of very salty water, which are entrapped within the sea ice. These pockets are known as “brines”.
Scientists sample these brines to measure the physical and bio-geochemical properties, such as: temperature, salinity, nutrient, water stable isotopes, Chlorophyll A, algal species, bacterial number and DNA, partial pressure of CO2, dissolved and particulate Carbon and Nitrogen, sulphur compounds, and trace metals. All of this helps to better understand how sea ice impacts the atmosphere-ocean exchanges of climate relevant gases.
In theory, sampling such brines is very simple: you just have to drill several holes in the sea-ice ensuring that the holes don’t reach the bottom of ice and wait for half an hour. During this time, the brine pockets which are trapped in the surrounding sea ice drain under gravity into the hole. After that, you just need to sample the salty water that has appeared in the hole. Simple…
…at least it would be if they didn’t have to deal with the darkness of the Antarctic winter, blowing snow, handling water at -30°C and all while wearing trace metal clean suits on top of polar gear…hence the faces!
Jean-Louis Tison is a professor at the Université libre de Bruxelles. His activities are focused on the study of physico-chemical properties of « interface ice », be it the « ice-bedrock » (continental basal ice) , « ice-ocean » (marine ice) or « ice-atmosphere » (sea ice) interface. His work is based on numerous field expeditions and laboratory experiments, and on the development of equipments and analytical techniques dedicated to the multi-parametric study of ice: textures and fabrics, stable isotopes of oxygen and hydrogen, total gas content and gas composition, bulk salinity, major elements chemistry…
5th August 2015, 10:30 in the morning. The meeting had to be interrupted to take this picture. We were aboard the Swedish icebreaker Oden, and were now closer than anyone before to the terminus of Petermann Glacier in northwestern Greenland. But we had not travelled that far just for pictures…
Petermann’s ice tongue
Petermann is one of Greenland’s largest “marine terminating glaciers”. As the name indicates, this is a glacier, i.e. frozen freshwater, and its terminus floats on the ocean’s surface. Since Petermann is confined within a fjord, the glacier is long and narrow and can be referred to as an “ice tongue”.
These are not isolated events. Greenland’s marine terminating glaciers are all thinning and retreating in response to a warming of both air and ocean temperatures (Straneo et al., 2013), and Greenland’s entire ice sheet itself is threatened. Hence, international fieldwork expeditions are needed to understand the dynamics of these glaciers.
Fig. 2: The 2010 calving event of Petermann. Natural-color image from the Advanced Land Imager (ALI) on NASA’s Earth Observing-1 (EO-1) satellite ( August 16, 2010). [Credit: NASA’s Earth Observatory]
The Petermann 2015 expedition
In summer 2015, a paleoceanography expedition was conducted to study Petermann Fjord and its surroundings, in order to assess how unusual these recent calving events are compared to the glacier’s past. Our small team focused on the present-day ocean, and specifically investigated how much of the glacier is melted from below by the comparatively warm ocean (that process has been described on this blog previously). In fact, this “basal melting” could be responsible for up to 80% of the mass loss of Petermann Glacier (Rignot, 1996). Additionally, we were also the first scientists to take measurements in this region since the calving events.
Our results are now published (Heuzé et al., 2017). We show that the meltwater can be detected and tracked by simply using the temperature and salinity measurements that are routinely taken during expeditions (that, also, has been described on this blog previously). Moreover, we found that the processes happening near the glacier are more complex than we expected and require measurements at a higher temporal resolution, daily to hourly and over several months, than the traditional summer single profiles. Luckily, this is why we deployed new sensors there! And since these have already sent their data, we should report on them soon!
I cannot believe that a full year has passed since this very cute pink unicorn wished you a Happy New Year.
Yet, over the past 12 months our blog has attracted more than 16,200 visits. And the blog analytics show that you, our dear readers, are based not only in Europe but literally all over the world!
With 67 new posts published in only 52 weeks, it’s more than likely that you missed a few interesting ones. Don’t worry, today’s Image Of the Week highlights some of the most exciting content written, edited and published by the whole cryo-team during the year 2016!
Enjoy and don’t forget to vote in the big EGU Blog competition (see below) !
(Remark: all the images are linked to their original posts)
Get the most of 2016
Last glaciation in Europe, ~70,000-20,000 years ago [By S. Berger].
The 82 research stations in the Antarctic [By S. Berger].
We also launched our new “for dummies” category that aims at explaining complex glaciological concepts in simple terms. The first and most read “for dummies” is all about “Marine Ice sheet instability” and explains why West Antarctica could be destabilised.
Drilling an ice core [By the Oldest Ice PhD students]
Another welcomed novelty of 2016 was the first “ice-hot news” post, about the very exciting quest for the oldest ice in Antarctica. In this post — issued at the same time as the press release — the 3 PhD students currently involved with the project explain how and where to find their holy grail, i.e. the 1 million year old ice!
The list goes on of course, and I could probably spend hours presenting each of our different posts one by one and explain why every single one of them is terrific. Instead, I have decided to showcase a few more posts with very specific mentions!
The oddest place for ice : inside a volcano! [By T. Santagata]
The quirkiest ice phenomenon : ice balls [By E. Smith].
The most romantic picture : Heart-shaped bubbles for ValentICE’s day [By S. Berger]
The creepiest picture: Blood Falls, Antarctica [By E. Smith]
The funniest post : April Fools “do my ice deceive me” [By S. Berger]
The best incidental synchronisation: The Perito Moreno collapsed the day before our the post went live [By E. Smith]
The “do they really do that? ” mention for ballooning the ice [By N. Karlsson]
The best fieldwork fail : Skidoos sinking into the slush [By S. Berger]
The most epic story : Shackleton’s rescue [By E. Smith]
The most puntastic title “A Game of Drones (Part 1: A Debris-Covered Glacier” [By M. Westoby].
The most provocative title : “What an ice hole” [By C. Heuzé]
The soundest post where science is converted to music [By N. Karlsson]
Good resolutions for 2017
The beginning of a new year is a great opportunity to look back at the previous year, and one of the logical consequences is to come with good resolutions for the coming year. Thinking of a good resolution and then achieving it can however be tricky. This is why we have compiled a few resolutions, that YOU dear cryo-followers could easily make 🙂
Olaf the snowman begs you to vote for “the journey of a snowflake”
From now until Monday 16th January, we invite you, the cryo-readers, to vote for your favourite post of 2016, which should be “journey of a snowflake” (second-to last option). I am obviously being totally objective but if you’re not convinced, the little guy on the right might be more persuasive. If you’re really adventurous, you could also consider clicking on other posts to check what they look like, after having voted for the cryo-one, of course.
Hopefully by now:
You are convinced that the cryosphere is amazing and that the EGU cryoblog enables you to seize some of the cryo-awesomeness
You have read and elected the “journey of a snowflake” as the best post of 2016
You would like to contribute to the blog (because you would like to be part of this great team or simply because you think your sub-field is not represented well enough).
Not to confuse you with a long speech, the image below explains how to get involved. We always welcome contributions from scientists, students and professionals in glaciology, especially when they are at the early stage of their career.
E. Bagshaw (University of Cardiff, UK) listening for the bleep from a wireless sensor buried in the snow a few hundred metres away. [Credit N. B. Karlsson].
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!
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.
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“.
…but before that let’s have a look first at what makes Antarctica so special!
Antarctica, a very peculiar continent, regulated by the Antarctic treaty
Antarctica is regulated by the Antarctic Treaty that defines this continent as a “natural reserve, devoted to peace and science” (Environmental Protocol, 1991). This means that since the treaty came into force in 1961:
Antarctica has been demilitarised and no nuclear tests are allowed
International collaboration in the name of progressing scientific research is encouraged, with many countries with greater operational capacity aiding those with little or none to allow them to conduct research.
Who is conducting research in Antarctica and where?
Mc Murdo Station on Ross Island (West Antarctica). The station is operated by the US Antarctic Program and can accommodate up to 1,000 people. [Credit: Gaelen Marsden on Wikimedia Commons]
The map above shows the 82 permanent research stations dotted across the Antarctic. Among those bases, 40 are operated all year long while the others only host scientific research during the Austral summer (November-February). The location and capacity of these stations also varies considerably from one to another. For instance, the US McMurdo station – the biggest scientific base in Antarctica – is settled on an island and is open all year-ong, accommodating up to 1,000 people during summer. On the contrary, a small seasonal station such as the Belgian Princess Elisabeth Station is only open during the summer and can host up to 20 people.
The Belgian Princess Elisabeth Station, (Dronning Maud Land, East Antarctica). This station is only open during the austral summer and is located hundreds of kilometres away from from the coast. [Credit: René rober – International Polar Foundation]
The research supported by these scientific stations is very broad and covers topic as diverse as sea level rise, climate change, observation of space, biodiversity, etc… Much of this happens in the austral summer when field parties are able to travel from the research stations into even more remote areas of the continent to conduct experiments and install equipment. However, some science, such as meteorology and weather observations takes place all year round no matter how cold, windy and inhospitable the continent may be for those conducting the research.
A phase of the laser scanning survey of the southernmost ice mass in Europe: the Ice Cave, Mount Etna,. [Credit: Alessio Romeo – Inside The Glaciers Project]
Who would think that one of the world’s most active volcano shelters the southernmost persistent ice mass in Europe!?
Yes, you can find ice inside Mount Etna!
Located at an altitude of about 2,040 m above sea level, the Ice Cave (Grotta del Gelo) is well known among Mt Etna’s volcanic caves due to the presence of columns of ice on its walls and floor which occupy about the 30% of the cave’s volume and persist all year round.
How did the ice get there and why does it remain?
This cave – a small lava tube of less than 100 metres long – was formed during Etna’s longest eruption that occurred on its northern flank from 1614 to 1624 A.D. (Marino, 1999)
Once formed, the cave was subsequently filled with ice.
The shape of the cave enables the ice to persist because there is only one single entrance to the ice cave that insulate the air from the outside. This enables the temperature to stay below 0°C in some parts of the cave all year round. This is not the case with other lava tubes around Etna that have several entrances, which allows the air to circulate within the caves, causing warming
Exploring the Ice Cave
By studying ice inside caves, researchers can obtain very useful biological and paleo-climatological information. Although we don’t know much about the conditions of the ice mass and its evolution over the last few centuries, speleologists (Centre Speleogico Etneo) and scientists (Italian National Institutites of Geophysics and Volcanology) have studied the cave for the past 20 years.
The use of new technologies such as UAV’s (see THIS or THIS previous blog posts about other applications of UAVs in glaciology) or terrestrial laser scanners on glaciers and ice caves can give the possibility to monitor surface variations of hidden underground areas that have never been affected by human activities.
After a long walk of about 4 hours through beautiful volcanic landscapes, the Inside The Glacier teamarrived at the entrance of the cave. There they surveyed the Ice Cave for 5 hours, performing 17 scans to detect the ice mass with very high accuracy.
With these measurements it was possible to draw detailed topographic plant and sections of the cave and derive 3D models of its surfaces, obtaining first data that will be compared in future with other laser scanner surveys to help scientists to study the evolution of the ice mass inside the cave.
Topographic plant and profile of the Ice Cave derived from laser scanning data. Ice deposits are represented in cyan color.[Credit: Tommaso Santagata]
This expedition was organized within the “Inside The Glaciers” Project in collaboration with the Association La Venta Esplorazioni Geografiche, Etna Natural Park, Italian National Insitute of Geophysics and Volcanology (I.N.G.V.), Centro Speleologico Etneo, Federazione Speleologica Regionale Siciliana, Gruppo Servizi Topografici s.n.c.
(Edited by Sophie Berger and Emma Smith)
Tommaso Santagata is a survey technician and geology student at the University of Modena and Reggio Emilia. As speleologist and member of the Italian association La Venta Esplorazioni Geografiche, he carries out research projects on glaciers using UAV’s, terrestrial laser scanning and 3D photogrammetry techniques to study the ice caves of Patagonia, the in-cave glacier of the Cenote Abyss (Dolomiti Mountains, Italy), the moulins of Gorner Glacier (Switzerland) and other underground environments as the lava tunnels of Mount Etna. He tweets as @tommysgeo
Field Site, Imja Lake, in November 2015 [Credit: D. Rounce]
Imja Lake is one of the largest glacial lakes in the Nepal Himalaya and has received a great deal of attention in the last couple decades due to the potential for a glacial lake outburst flood. In response to these concerns, the UNDP has funded a project that is currently lowering the level of the lake by 3 m to reduce the flood hazard. The aim of our research efforts is to understand how quickly the glacier is melting and how rapidly the lake is expanding such that we can model the flood hazard in the future. The focus of this research expedition was to install an automatic weather station, measure the thickness of the ice behind the calving front of Imja Lake, and measure the bathymetry of Imja Lake amongst other smaller tasks.
However, before any work could be done, we had to get there first.
The 8-day trek from Lukla to Imja Lake [Credit: GoogleEarth]
The long trek in
Tenzing-Hillary Airport in Lukla, at an altitude of 2,845 m [Credit: D. Rounce]
The launch point for our expedition was Kathmandu, Nepal, where we met with our trekking agency, Himalayan Research Expedition, purchased any last minute supplies, and took a day to kick our jet lag. Then the real trip began with a flight from Kathmandu to Lukla. Depending on the weather, this flight can be smooth and showcase the splendor of the Himalaya or it can be nerve-wracking flying through turbulence and clouds. Unfortunately, we had the latter and spent most of the 30-minute class flying through white clouds. Once our feet touched the ground at Tenzing-Hillary Airport, we were all excited and ready to start trekking.
Located at 5010 m above sea level (a.s.l) in the Everest region of the Himalaya, Imja Lake required 8 days of trekking to reach our base camp. The first 6 days followed the route to Everest Base Camp and provided the first glimpses of Everest, Lhotse, and Ama Dablam among many others. Due to the late start of our trek on May 29th, the monsoon clouds often blocked most of these peaks, so whenever the skies did clear we enjoyed them thoroughly. The 8-day trek also included two rest days (one in Namche and one in Dingboche) that were critical to be properly acclimated. The general rule of thumb that we follow is an acclimatization day for every 1,000 m of elevation gain. After the first rest day at Namche, at 3,400 m.a.s.l., the effects of altitude began to set in. The trekking slowed down as oxygen was a bit harder to come by. By the time we reached Imja Lake, there was about half as much oxygen as there is at sea level.
At 5,000 meters in altitude there is about half as much oxygen as there is at sea level
Imja Lake looked…different
The team at our base camp at Imja Lake [Credit: D. Rounce]
I was beyond excited to be back at Imja Lake. This was my 5th time at the lake and this time I was accompanied by a great team of colleagues. This project is funded by the NSF’s Dynamics of Coupled Natural and Human Systems (CNH) program and is led by Daene McKinney (University of Texas), Alton Byers (University of Colorado Boulder), and Milan Shrestha (Arizona State University). One of the great aspects of this trip was we were all able to be in the field at the same time providing an excellent mix of fieldwork on the glacier and social science work with the communities downstream. My group consisted of myself, Greta Wells from the University of Texas, Jonathan Burton from Brigham Young University, Alina Karki from Tribhuvan University, and eight hard-working individuals from our trekking agency (unfortunately, Daene was with us, but had to leave the expedition early).
The first drastic change that we saw when we got to Imja Lake was the large camp set up by the Army to work on the lake-lowering project. Usually, the only people that we see up here are people at Island Peak base camp, but now the location where were typically set up camp was packed with tents for the workers. The next surprise was seeing a backhoe operating on the terminal moraine (the natural dam comprising sand, rocks, and boulders). Typically, once you get off the plane in Lukla, you don’t see any motorized transportation besides the occasional helicopter flying to Everest Base Camp, so seeing this large piece of construction machinery was quite surprising! The lake lowering project was fascinating to see in progress. A cougher dam has been established to divert the outlet stream such that the typical outlet can be dredged and an outlet gate established, which will reduce the lake level by 3 m. This is a large undertaking due to the difficulty of working at 5,000 m (for both the workers and the machinery), but is an excellent step forward for Nepal in addressing the hazards associated with their glacial lakes.
The lowering project in progress at Imja Lake, with a backhoe working on a terminal moraine [Credit: D. Rounce]
Seeing this large piece of construction machinery [at that altitude] was quite surprising!
Let the work begin
On June 6th, we woke up at 6:00 a.m. to pure fog and limited visibility – not the weather you hope for on your first day of fieldwork. Fortunately, the fog burned off as the sun came up giving us a nice partly cloudy day to perform our reconnaissance of the glacier for the upcoming work. The first task was figuring out how to get onto the glacier from the lateral moraines (the sides of the glacier). This may sound trivial, but the glacier has melted such that the lateral moraines are now over 100 m higher than the debris-covered glacier surface and their slopes are very steep, which makes descending down them quite difficult. Fortunately, we found a good spot near Island Peak base camp, where Laxmi (our guide) set a rope and cleared the path of loose rocks and boulders.
Arduous descent onto the glacier [Credit: D. Rounce]
The glacier has melted such that the lateral moraines are now over 100 m higher
Automatic Weather Station on Imja-Lhotse Shar Glacier [Credit: D. Rounce]
Once on the glacier, we were tasked with determining the location of the weather station and wind tower in addition to finding potential routes for our Ground Penetrating Radar transects. The problem with Imja-Lhotse Shar Glacier is there are very few suitable flat spots. The debris cover on the glacier consists of fine sands, gravel, and boulders with melt ponds and bare ice faces scattered over the surface. The thickness of the debris can range from these bare ice faces to a thin cover of a few centimetres to many meters thick. Needless to say, the heterogeneous terrain can make walking on its surface quite difficult. My initial thought was to use a location where we had installed temperature sensors and ablation stakes two years ago; however, this site had turned into a melt pond ! Hence, we need to select a spot that seems relatively stable such that it won’t be in the middle of a pond when we return!
After many hours of trekking on the glacier, we returned to camp fatigued. The altitude wears you down quickly, especially in the first couple of days, so it’s crucial to stay hydrated, warm, and well rested such that we can work hard for all of the 16 scheduled days that we were out here. I find the first couple days to be the most difficult as my body adjusts to the limited supply of oxygen and for the first 2-3 days I typically have a mild headache in the afternoon. A good meal of dal baht (rice, lentil soup, and typically a meat or vegetable curry) along with a good night’s sleep and a little ibuprofen does the trick to have me feeling refreshed the next day though.
The first task was to set up the weather station and wind tower. The weather station will record meteorological data every 30 minutes that is important for energy balance modelling. This will allow us to model melt rates that can be applied to the entire glacier such that we can understand the evolution of the debris-covered glacier – crucial for future hazard modelling! The wind tower allows us to measure the surface roughness of the topography, which influences the turbulent heat flux transfers, i.e., the transfer of heat and moisture between the surface of the debris and the air – an important debris property to measure for energy balance modelling as well. Additionally, beneath the weather station, we installed temperature and relative humidity sensors within the debris such that we can understand how heat is transferred through the debris. Each piece of equipment has an essential role in the energy balance modelling.
The other large undertaking in the first week was performing ground penetrating radar (GPR) transects on Imja-Lhotse Shar Glacier. GPR is a geophysical technique that is used to measure and detect objects beneath the surface. In our case, we’ll be trying to measure the ice thickness of the glacier.
Ground Penetrating Radar in short
Ground Penetrating Radar survey in action [Credit: D. Rounce]
The quick and dirty of GPR is you have a transmitter and a receiver. The transmitter sends a great deal of energy into the ground, which then reflects off various surface, e.g., we should see a strong reflection at the ice/rock interface, and this reflected signal is then picked up by the receiver. Sounds easy right?
Things become a bit more difficult when you get on the debris-covered glacier and everything must be carried or dragged across the surface. This requires a lot of people such that the antennas don’t get stuck on the boulders, requires everyone to be walking at the same speed, and requires that all the electrical connections, batteries, etc. are secure and operating.
In a nutshell, it is a great deal of work, but provides an excellent dataset to understand the extent to which glacial lakes may grow in the future.
When this ice thickness is paired with lake expansion rates, one can predict the evolution of the glacial lake, which is critical for understanding the future hazard associated with Imja Lake. Two full days were spent climbing over the glacier, around bare ice faces and melt ponds, and attempting to collect transects that provide a good picture of the ice thickness behind the calving front of Imja Lake. During these days, we completed half of our planned transects and were ready for our first day of rest.
A flood and a community meeting
After 6 days of hard work, I was exhausted. The plan was to hike down to Chukung at 4700 m.a.s.l., where we would stay for two nights. A change in 300 m may not sound like a lot, but at altitude, this can provide a great boost in energy. During our “rest day” in Chukung, we were planning to hike down to Dingboche (4400 m.a.s.l.) to help out with a focus group session with the community led by Milan. What happened next was completely unexpected… we witnessed a glacier flood!
We witnessed a glacier flood!
A glacier flood threatened the village of Chukung [Credit: D. Rounce]
Our colleagues Alton and Elizabeth Byers were heading down to Dingboche before us. Along the way, they heard the sound of a landslide and when they checked to see what it was they were surprised to witness the start of a glacier flood. These floods appeared to have originated from the drainage of supraglacial lakes on Lhotse Glacier and appeared to have discharged through a series of englacial conduits. This englacial conduit flood grew rapidly as the initial flood continued to melt the surrounding ice. The videos that Elizabeth took were absolutely remarkable and fortunately everyone in Chukung was safe. By the time we arrived at the typical crossing point around 3:00 p.m., the flood had supposedly diminished by quite a bit, but was still very powerful. We ended up having to an hour detour over an ice bridge (literally a place on the glacier where the flood had carved into the ice and was going underneath the glacier such that we could walk above the flood on the debris-covered surface). It was truly fascinating to witness a flood from a glacier. When we arrived at Chukung, we made the decision to continue hiking to Dingboche such that we were safely out of the potential flooded area.
The energy in Dingboche was electric. Our entire NSF group was in the lodge and eager to talk to one another. The flood had also sparked a great deal of interest with community members as they witnessed the flood coming downstream and were fortunately able to contact members in Chukung to learn that this was not a larger glacial lake outburst flood (GLOF) from Imja Lake, which alleviated a great deal of concern. After a good meal and great conversation, we were all exhausted and went to bed early (not to mention that for the first time in over a week we were able to reconnect and update family and friends on the internet, which was a wonderful treat as well). The next day we were able to sit in on Milan’s focus group session with the members of Dingboche. From my background in engineering, I was fascinated to see first-hand the important work that Milan was conducting with the community. The community member’s interest and questions were very inspiring. For many years, these communities have seen researchers come to Imja Lake and not share any of their results. This has led to a great deal of skepticism and also led to unnecessary fear and/or panic, so every opportunity that we have to share our results and have a dialogue with the community is crucial. It is wonderful to be working with Milan as his work is a wonderful vessel for us to learn about the community’s concerns and vice versa, for us to share our work with them as well. I’m incredibly excited to see how this work progresses and see the field science and the social science come together.
The community of Dingboche [Credit: D. Rounce]
Every opportunity that we have to share our results and have a dialogue with the [local] community is crucial
Finishing off the fieldwork
After a day of “rest” in Dingboche, our team was ready to get back to work at Imja Lake. The first task was more GPR transects on the glacier. The benefit was that we were all feeling rejuvenated from our days at lower elevations and now that this was our 3rd day of GPR things were running smoothly.
The other benefit was that after almost 10 days at 5000 m.a.s.l. our bodies were feeling well adjusted to the limited supply of oxygen. The headaches that came and went over the first couple days were non-existent. The only downfall was we were now getting into the heart of the monsoon season, where clouds came up the valley every morning and it rained almost every afternoon. The work had to go on though, so we simply shifted our wake-up time an hour earlier in an attempt to avoid the rain.
Greta Wells and Jonathan Burton conducting a bathymetric survey on Imja Lake [Credit: G. Wells]
As our days were winding down, it was time to start splitting up the group. Jonathan and Greta became our kayaking experts and quickly became adept at working the sonar system to conduct a bathymetric survey of Imja Lake. The bathymetric survey is a remarkable experience and one that Jonathan and Greta seemed to thoroughly enjoy. The calving front of Imja Lake is ~10-20 m tall, which seems huge from the view of a kayak on the water. Furthermore, the calving front is quite active each year, so there are icebergs floating on the surface that provide some fun obstacles during the survey. They did a wonderful job and I am incredibly thankful for their support.
While the bathymetric survey was being conducted, Alina and I worked on the Structure from Motion (SfM) survey and the operation of the differential GPS (dGPS). Structure from Motion is a technique that allows us to take hundreds of pictures of the debris-covered surface and transform these pictures into a digital elevation model using the software PhotoScan Pro.
differential GPS measurement of a ground control point [Credit: D. Rounce]
This technique requires ground control points, which is where the dGPS comes into play. The differential GPS provides centimetric accuracy of specific points on the glacier (in our case spray painted boulders), which provide the spatial scale for the digital elevation model. We had ~40 ground control points and each point took approximately 10 minutes to measure… hence, the dGPS survey was a great deal of work. Once again, I have to thank my wonderful colleague, Alina, for her hardwork operating the dGPS with me.
The bathymetric survey, SfM, dGPS, and GPR transects occupied all of our remaining time on the glacier. Two days before I left the glacier, I sent our team members off to visit Everest Base Camp and Kala Patthar as the only activities left were finishing off the dGPS survey and downloading the last bit of meteorological data from the weather station. The trek to Everest Base Camp takes about 2 days from our site and I was glad that they would have an opportunity to go visit – they certainly deserved it. Perhaps one of the best surprises of the trip was the day that Jonathan, Greta, and Alina went to Kala Patthar, they had a couple hours of clear skies in the morning such that they were able to see Everest! What a better way to end the trip for them. On my side, the last couple days went very smoothly and I was ecstatic with all the work that we had accomplished. 16 days of hard work paid off and I am anxiously waiting for us to return and collect all the remaining data next year!
A special thanks to the NSF-CNH program for funding this research. Also a big thanks to my colleagues Daene McKinney, Alton Byers, Elizabeth Byers, Milan Shrestha, Greta Wells, Jonathan Burton, and Alina Karki among the countless others who were with Alton and Milan’s groups. Lastly, this work would not be possible without the tremendous effort and support provided by Himalayan Research Expedition and our team of guides, porters, and cooks.
In 2010 thick ash poured from Iceland's Eyjafjallajökull volcano after an explosive eruption. Find out more about why this happened at the Explosive Earth Exhibit at this weeks Royal Society Summer Science Exhibition. Photo Credit: Eyjólfur Magnússon
The Royal Society Summer Science Exhibition (RSSSE) is a free public event 4-10th July 2016 in London. This is a yearly event that is made up of 22 exhibits, selected in a competitive process, featuring cutting edge science and research undertaken right now across the UK. The scientists will be on their stands ready to share discoveries, show you amazing technologies and with hands-on interactive activities for everyone! The Royal Society has historic origins – going back to the 1660s and today it is the UK’s national science academy working to promote, and support excellence in science and to encourage the development and use of science for the benefit of humanity. If you can get yourself down to London this week then it is definitely worth a look!
The Royal Society Summer Science Festival Exhibit Hall. Photo Credit: Jenny Woods
What is there to see?
This year there are a number of ice-related exhibits. The “4D science” exhibit uses X-ray computer tomography to look inside ice cream and the “Explosive Earth” exhibit showcases ice-volcano interactions in Iceland using earthquakes. The Summer Science Exhibition yearly attracts around 12,000 visitors. This is a unique opportunity to meet cutting edge scientists, discover their research and try out fun and engaging activities for yourself.
Left: The Explosive Earth presented by the Cambridge University Volcano Seismology Group. Right: 4D Science: Diamond Light Source, University of Manchester and University of Liverpool – Looking inside materials through time. Photo Credit: Jenny Woods
The Explosive Earth exhibit has been put together by the Cambridge Volcano Seismology group. They explore many applications of volcano seismology, from what we can learn about movement of molten rock (magma at more than 1000°C) in the Earth’s crust and rift zone dynamics, to the very structure of the earth itself. They currently focus their research in central Iceland where they operate an extensive seismic network in and around some very active volcanoes, many of which are under Europe’s largest ice cap Vatnajökull. The seismic network detects tiny earthquakes caused by the movement of magma beneath the surface, which often occurs under volcanoes prior to eruption. By studying these seismic events, they hope to be able to predict volcanic activity better in the future. Their exhibit at RSSSE showcases current research in this explosive field of volcano seismology.
Eyjafjallajökull – 2010: an explosive eruption that disrupted air traffic
The 2010 eruption at Eyjafjallajökull (image at the top of the page) occurred beneath a glacier, which caused a highly explosive eruption. When hot magma comes into contact with ice the magma cools and contracts and the ice turns to steam and rapidly expands. This shatters the solidifying magma and produces ash. The explosivity of the interaction, and the pressure of all the rising magma underground, blows the mixture of ash, volcanic gases and steam high into the air, creating an eruptive plume. The 2010 Eyjafjallajökull eruption produced an ash plume that reached up to 10 km (35,000 feet). The fine ash was then carried 1000’s of km by the wind towards Europe where it grounded over 100,000 flights.
Installing seismometers in a variety of locations around Iceland to monitor tiny earthquakes from magma movement under the surface. Photo Credits – Left: Rob Green, Right: Ágúst Þór Gunnlaugsson
Bárðarbunga-Holuhraun – 2014: a gentle eruption that affected air quality
In 2014 a completely different kind of eruption happened in central Iceland, also originating from a volcano under the ice. Magma flowed underground from Bárðarbunga volcano, beneath Vatnajökull ice cap, fracturing a pathway so far from the volcano that when it erupted there was no ice at the surface. Without the magma-ice interaction, the eruption was comparatively gentle and the molten rock simply fountained out of the ground, reaching heights of over 150 m. No ash was produced, only steam and sulphur-dioxide. The amount of magma erupted was much greater than in 2010 (an order of magnitude higher), but there was no impact on air travel because there was no ash plume. The Explosive Earth team are investigating the 30,000 earthquakes that led up to this spectacular six-month eruption in Iceland, to try and find out more about what happened and why. The earthquakes tracked the progress of the molten rock as it moved underground, away from Bárðarbunga volcano to the eventual eruption site at Holuhraun, 46 km away.
The fountains of lava accompanied by clouds of steam and sulphur-dioxide. The magma flowed 46 km underground from Bárðarbunga volcano to the eventual eruption site at Holuhraun, where it erupted continuously for 6 months. Photo Credit: Tobias Löfstrand
Cambridge Volcano seismology group in front of the fissure eruption on the first day of the 2014-15 Bárðarbunga-Holuhraun eruption. Photo Credit: Thorbjörg Águstsdóttir
What can monitoring these earthquakes tell us?
Monitoring volcanic regions in Iceland is important because eruptions are frequent and have wide-range impacts:
Explosive eruptions under ice can cause rapid and destructive flooding of inhabited areas downstream, and can propel huge ash clouds into the atmosphere, disrupting air travel around the globe.
Gentle eruptions, producing large lava flows, can release millions of tones of harmful gases, affecting the local population and in some cases the global climate.
Studying earthquakes helps to understand the physical processes that occur in volcanic systems, such as how molten rock intrudes through the Earth’s crust and how the centre of a volcano collapses. The more we understand about the behaviour of these systems, the better we can forecast eruptions.
“Explosive Earth” exhibits earthquakes and eruptions in Iceland in a fun interactive way. You can find out more details of the science behind why and how these eruptions happen and how it is possible to monitor volcanic activity in Iceland using earthquakes. As a taster of what you can see, try entering your postcode into theirlava flow game to see how big the Holuhraun lava flow is and how far it travelled underground prior to erupting. Other interactive activities include making your own earthquake and testing your reaction times with an earthquake location game.
(Edited by Emma Smith and Sophie Berger)
Thorbjörg Águstsdóttir (Tobba) is a PhD student at the University of Cambridge studying volcano seismology. Her research focuses on the seismicity accompanying the 2014 Bárðarbunga-Holuhraun intrusion and the co- and post-eruptive activity. She tweets as @fencingtobba, for more information about her work see her website.
Figure 1: Down-glacier view of debris-covered Miage Glacier, Italy, taken from a low-altitude lightweight UAV in June 2016 (Credit: M. Westoby). As the summer progresses, the melting of winter snow cover prompts the development of a surface drainage network, characterised as a network of streams and ponds, which are concentrated in intermoraine troughs and drain into open crevasses or moulins. Snowmelt in this area will eventually reveal a glacier surface covered by a continuous mantle of supraglacial debris, comprised predominantly of mica-schist
What are debris-covered glaciers?
Many alpine glaciers are covered with a layer of surface debris (rock and sediment), which is sourced primarily from glacier headwalls and valley flanks. So-called ‘debris-covered glaciers’ are found in most glacierized regions, with concentrations in the European Alps, the Caucasus, Hindu-Kush-Himalaya, Karakoram and Tien Shan, the Andes, and Alaska and the western Cordillera of North America. Debris cover is important for ice dynamics for several reasons:
A layer of surface debris thicker than a few centimetres suppresses ice ablation (Brock et al., 2010), as it insulates the underlying ice from atmospheric heat and insolation.
In contrast, a thin layer of debris serves to enhance melt rates through reduced albedo (reflectance) and enhanced heat transfer to underlying ice.
A continuous or near-continuous layer of debris can result in debris-covered glaciers persisting at lower elevations than, and attaining lengths which exceed those of their ‘clean ice’ counterparts (Anderson and Anderson, 2016).
Miage Glacier – the largest debris-covered glacier in the European Alps
The Ghiacciaio del Miage, or Miage Glacier, is Italy’s longest glacier and is the largest debris-covered glacier in the European Alps. It is situated in the Aosta Valley, on the southwest flank of the Mont Blanc/Monte Bianco massif. The glacier descends from ~3800 m to ~1700 m above sea level (a.s.l.) across a distance of around 10 km, and is fed by four tributary glaciers. The glacier surface is extensively debris-covered below ~2400 m a.s.l., and the average surface debris thickness is 0.25 m across the lower 5 km of the glacier (Foster et al., 2012).
Figure 2: Up-glacier view of Miage Glacier, in which three of the glacier’s four tributaries are visible – from upper centre-left: Tête Carée Glacier, Bionnassay Glacier, Dome Glacier.
Glacier surveying using Unmanned Aerial Vehicles
Researchers from Northumbria University, UK, acquired these images of the glacier using a lightweight unmanned aerial vehicle (UAV) during a recent field visit to Miage Glacier. During the visit the team carried out a range of activities including the installation and maintenance of a network of weather stations and temperature loggers across the glacier and geomorphological surveying of the glacier and its catchment, whilst undergraduate students collected data for their final-year research projects. The UAV imagery reveals the emergence of surface debris cover from beneath winter snow cover and the persistence of a channelized hydrological network in the snowpack, characterised as a cascade of streams and storage ponds. A recent study by Fyffe et al. (2015) found that high early-season melt rates and runoff concentration in intermoraine troughs promotes the development of a channelized subglacial hydrological system in mid-glacier areas, whilst the drainage system beneath continuously debris-covered areas down-glacier is largely inefficient due to lower melt inputs and hummocky topography.
(Edited by Emma Smith and Sophie Berger)
Matt Westoby is a postdoctoral researcher at Northumbria University, UK. He is a quantitative geomorphologist, and uses novel high-resolution surveying technologies including repeat UAV-based Structure-from-Motion to quantify surface processes and landscape evolution in glacial and ice-marginal environments. Fieldwork on the Miage Glacier in June 2016 was supported in part by an Early Career Researcher Grant from the British Society for Geomorphology. He tweets as @MattWestoby Contact e-mail: email@example.com
One man and his balloon. Field leader Prof. J. P. Steffensen (Centre for Ice and Climate, University of Copenhagen) in front of one of the balloons used in camp. Credit: S. Kipfstuhl.
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.
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.
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.