Tunabreen is a tidewater glacier in Svalbard that has recently been displaying some exciting activity. It is known as a surge-type glacier, with discrete periods where it flows markedly faster and slower. Tunabreen entered a fast-flowing phase in December 2016, which is ongoing at the time of writing. The nature of this fast-flowing phase is atypical for Tunabreen though, throwing into question whether this phase is associated with surge dynamics. What is going on at Tunabreen?!
Tunabreen is an ocean-terminating glacier on the west coast of Svalbard. This glacier is particularly special because of its unique set of dynamics. A large number of the glaciers in Svalbard are known as surge-type glaciers. A surge-type glacier undergoes periods of fast-flow followed by very slow, inactive phases. The nature of this surging pattern is due to the glacier’s inefficiency in transferring mass from its upper regions to its terminus (Sevestre and Benn, 2015). It is an internally-driven process. The trigger of this process is unrelated to external influences (i.e. changes in air temperature, ocean temperature, and precipitation).
Tunabreen is one of few glaciers in Svalbard to have been observed to undergo repeated surge cycles. It has surged in 1870, 1930, 1971, and between 2002-2005. We know these surges happened because each surge phase left a pronounced ridge on the seabed which defines the surge extent (Flink et al., 2015). As these surges have been spaced 30-60 years apart, the next surge was not expected for quite a while (at least until 2030).
Tunabreen was a very slow-moving glacier between 2005 and 2016, flowing between 0.1-0.4 metres per day (m/day). These velocities were largely derived from sequential satellite imagery. Distinct glacial features were tracked from image to image to determine surface velocities on the glacier. The highest velocities (0.4 m/day) were limited to the terminus area, with very little movement (0.1 m/day) in the upper section of the glacier tongue. It was often difficult to track glacial features from image to image because the glacier was moving so slowly.
A marked speed-up was initially observed at Tunabreen in December 2016. The entire glacier tongue suddenly flowed faster. The terminus flowed >3 m/day and velocities in the upper section increased to 0.3-2.0 m/day. This speed-up continues at the time of writing this blog post (March 2017). It is a dramatic difference from the months and years prior to this event.
So, is this a surge? is the question on everyone’s lips now. In short, we don’t know at the moment and this is a difficult question to answer with the short amount of time that we have witnessed these changes at Tunabreen. At the time of writing, there are 4 key observations that need to be considered:
- The timing of this speed-up coincides with record-high temperatures and precipitation for a winter season in Svalbard (as stated in this article by Chris Borstad, a glaciologist at UNIS). This could have had a significant influence on the presence of water at the bed of the glacier, which is understood to lubricate the interface between the ice and the underlying bedrock. This, in turn, promotes sliding and may also cause the glacier to flow faster.
- This winter, sea ice did not form in Tempelfjorden and the fjord area directly adjacent to the glacier front. Sea ice and melange is understood to provide a back-stress against the front of a glacier. This acts as an opposing force to ice flow. Without the presence of sea ice, this opposing force is absent at the front of Tunabreen. Lack of sea ice was also observed in the winter of 2015 (as noted here in a previous blog post).
- The spatial pattern of this speed-up propagated in an upward fashion i.e. an increase in velocity first occurred at the front of the glacier, with subsequent velocity changes progressing up the glacier tongue. The abundance of crevasses on the glacier surface has increased, with the crevasse field extending much further up the glacier tongue than previously. Also, the terminus has advanced roughly 400 m since December 2016, as shown from the sequence of Sentinel images tweeted by Adrian Luckman (and displayed in a post by St. Andrews Glaciology). These observations are indicative of surging dynamics, as stated by Sevestre and Benn (2015).
- This speed-up has occurred 12 years after the previous surge (2002-2005). Surges at Tunabreen have previously been spaced 30-60 years apart from one another. The next surge was not expected until at least 2030. If this speed-up is associated with surge dynamics then it has occurred much earlier than anticipated.
These observations can be used as arguments for and against this speed-up being associated with surge dynamics. Whilst the behaviour of the glacier indicates that this may be associated with surge dynamics, there have also been significant changes in external factors which could have played a crucial role in this speed-up. It is important to continue monitoring changes to better understand the processes behind the abnormal behaviour at Tunabreen. It will be interesting to see if this speed-up is sustained through the spring of 2017, and to see how much the terminus will continue to advance into Tempelfjorden. One thing is for certain: all eyes will be on Tunabreen and what it does next!
Sevestre and Benn (2015) – A comprehensive study on surge-type glaciers and their distribution around the world.
Flink et al. (2015) – Past surge extents at Tunabreen determined by topographic features on the sea bed, derived from multibeam-bathymetric surveying over Tempelfjorden.
Thanks to some nice boat trips this September (and a good zoom lens on my camera*), we were able to take a detailed look at the calving front of Kronebreen, a fast-flowing glacier which terminates into Kongsfjorden, an inlet on the west coast of Svalbard. Since 2011, Kronebreen has been retreating significantly faster (approx. 100m per year) and the front (where the ice meets the fjord water) has changed drastically. What is interesting is that the calving front does not appear uniform – the distinctiveness of each section indicates that different processes are active. If this intrigues you then please read on! If not, then sit back, relax, and enjoy the pictures at least!
All photos were taken on the Sony NEX-5R with the Sony E 55-210 mm f/4.3-6.3 lens and the Sony E 20 mm f/2.8 lens.
Kronebreen (‘crown glacier’) is a heavily crevassed glacier tongue fed from a large ice field called Hotledahlfonna, flowing between 1-5 metres per day into Kongsfjorden, an inlet on the west coast of Svalbard (see here for more information on Kongsfjorden and Svalbard). The front of Kronebreen is approximately 3 km, forming an impressive ice face that deposits ice into the fjord to form icebergs. This process is called calving and is one of the main processes by which ice is transferred from land to sea. For more information on Kronebreen, please refer to another post I wrote on why small glaciers are important to study here.
In many settings (such as at the large glaciers found in Greenland), the front of a glacier is a tall cliff of ice from which large sections of ice calve off. From studying the front of Kronebreen though, it is apparent that the ice face is not uniform. Certain sections of the ice front look entirely different from one another, suggesting that the controls on calving are also different. There are five sections that are particularly interesting:
- The glacier margin next to Collethøgda
- The retreated region around a large submarine plume that forms during the summer melt season each year (since at least 2011)
- The pinnacle – the middle section of glacier that is the furthermost point of the ice front
- The ‘traditional’ tall ice cliff at the front of the fastest-flowing section of the glacier
- The shared margin with Kongsvegen
1. The glacier margin next to Collethøgda
2. Region around a large submarine plume
3. The pinnacle – the middle section of glacier that is the furthermost point of the ice front
4. The ‘traditional’ tall ice cliff at the front of the fastest-flowing section of the glacier
5. The shared margin with Kongsvegen
* All photos were taken from approx. 500m from the glacier front. It is generally advised to be AT LEAST 200 METRES from the front of any calving glacier in Svalbard. Being close to calving glaciers is dangerous and could result in serious injury or even death if a calving event were to occur. See here for more information issued by the Governor of Svalbard and Norsk Polarinstitutt, or google ‘glacier calving accident’ if you want to scare yourself silly.
AntarcticGlaciers.org article on stress and strain in glacial environments
Mauri Pelto’s AGU blog on the mutual margin of Kronebreen and Kongsvegen
Calving activity at Kronebreen by Anne Chapuis et al. (2010)
Submarine plumes in Greenland by Kristin Schild et al. (2016)
There are two motivations behind writing this blog post. One is to document the deployment of our time-lapse cameras for a third consecutive summer season at Kronebreen, which is a fast-flowing tidewater glacier in Svalbard. It is difficult to justify such intensive fieldwork without explaining why we are doing this research though. So the second reason for writing this is to explain why we are studying Kronebreen, and more importantly why findings from smaller glacier systems are just as significant as those from bigger catchments (i.e. Greenland and Antarctica). The take home message from this is that the study of smaller glaciers is essential to progressing our understanding of glacier dynamics which ultimately feeds into better prediction of future sea level rise.
DISCLAIMER: All opinions are my own and I encourage discussion on the subject matter. I’m all ears!
About Kronebreen and our research
Kronebreen is a heavily crevassed, elongated glacier located in Svalbard, the Arctic archipelago that is situated to the north of Norway. The glacier flows from an expansive ice field to a fjord called Kongsfjorden, which is connected to the Atlantic Ocean. The name Kronebreen literally translates to “crown glacier”, Kongsfjorden means “king’s fjord”, and a lot of the other glaciers in the area are named along this theme – for example, the two neighbouring glaciers to Kronebreen are Kongsbreen (to the north) and Kongsvegen (to the south) which mean “king’s glacier” and “king’s road”.
Where the front of Kronebreen meets the fjord water, a process called calving occurs. Calving is the mechanism by which ice detaches to form isolated icebergs. Calving was once considered a minor component of glacier dynamics, but is now understood to form a significant contribution to future sea level change. There are still many uncertainties concerning when and how calving at tidewater glaciers will occur in the future though, which makes it difficult to accurately predict future sea level change.
There are certain controls on calving which dictate the size of each ice piece that breaks off, and the frequency at which these events occur. Calving activity at Kronebreen is generally characterised as frequent and small (in comparison to larger glacier systems such as those found in Greenland and Antarctica). Calving has increased gradually year-on-year at Kronebreen, and the front has been retreating since the early 1900s (Nuth et al., 2012). Recent work has confidently linked this to warming of the Atlantic Ocean – Kronebreen and other glaciers in the Kongsfjorden are particularly susceptible because they are positioned close to a strong current of water (the West-Spitsbergen Current) which brings warm water from the south to the interior Arctic (Luckman et al., 2015).
We have been placing time-lapse cameras at Kronebreen for the past 3 years to monitor its calving activity and terminus position, along with its velocity and the presence of lakes on the glacier surface. We previously chose camera locations which produced images that adequately covered the entire glacier surface. This year we have placed our cameras much closer together, focusing on the first kilometre of the glacier front. The reasoning behind this re-shuffle is to ensure adequate overlap in the images from each camera, which we can use to attempt three-dimensional time-lapse. Using a technique called Structure-from-Motion, images taken from multiple angles can be used to form a three-dimensional model of a given object. In this case, we will produce Digital Elevation Models (DEMs), potentially every half an hour. This will give us a highly detailed look at how the front of Kronebreen changes over the summer season.
Myself and my supervisor, Nick Hulton (University of Edinburgh, University Centre in Svalbard), spent a week in Svalbard at the end of April installing our cameras, alongside researchers from Norsk Polarinstitutt who are looking more generally at changes in the Kongsfjorden area. The fieldwork was very successful and we installed 10 time-lapse cameras in total – 8 were installed at Kronebreen, and 2 were positioned at Kongsvegen and Kongsbreen. The weather was our main constraint, meaning we had to squeeze 7 of these installations into one day which took nearly 14 hours. Luckily, Svalbard is in 24-hour daylight at this time of year, which allowed us to work such long hours.
In my opinion, one of the biggest misconceptions in glaciology is that research on Greenland and Antarctica (i.e. ‘larger’ glacier systems) is more important than research on smaller glaciers. This is generally because the Greenland and Antarctica ice sheets are the largest contributors to future sea level rise. And yes, in a direct sense this is true, they are extremely important to study. Greenland and Antarctica hold 99% of the world’s freshwater ice and if that all vanished, sea level would rise by approximately 65 metres (IPCC, 2013). Often research on Greenland and Antarctica is published in higher-impact journals because of the direct importance of the findings. Research on smaller glaciers is just as important though, as the findings can have significant implications for larger glacier systems. It is just harder to convey this because the findings are usually limited to indirect implications.
Research on calving dynamics is a good example where studies have largely focused on Greenland and Antarctica (so far). Calving activity at Greenland and Antarctic mainly consists of rare, catastrophic events, such as calving across the entire ice cliff or complete collapse of an ice shelf (e.g. Larsen B Ice Shelf, Antarctica). Obviously, these types of events have a significant impact on future glacier dynamics and sea level change. Studies have largely focused on understanding this type of calving. This trend may be because this research is still largely in its infancy. The idea that oceans interact with glacier fronts was not considered particularly important until fairly recently (Straneo et al., 2010).
At the other end of the spectrum though, calving events can also be small and frequent. This type of calving has not been as thoroughly studied as larger calving styles so far. Small calving styles are often observed at smaller glaciers which are grounded on the sea bed (i.e. the base of the glacier sits on the sea bed rather than floating). Even though these calving events do not immediately impact the surrounding environment, they do promote instabilities at glacier fronts which can cause larger events (Åström et al., 2014). Again, smaller glaciers that exhibit small calving styles may not produce direct, immediate global impacts, but they are important facilitators for bigger processes and their contribution is significant in the long run.
Kronebreen is specifically being used for this study because it is at a very unique and interesting phase, distinguished in two aspects:
1. Since the 1900s, Kronebreen has retreated year-on-year. Often the front sits in similar position for a number of years (+/- 100 m in one year) and then rapidly retreats (+/- 1000 m in one year) to a new stable position (Schellenberger et al., 2015). For a number of years now, the front of Kronebreen has been gradually retreating. We have recently observed a marked stretching and thinning of the terminus area which happened over the winter season of 2014. It is also known that the bed on which Kronebreen sits is particularly deep in places just behind the glacier front. The combination of a thin terminus and a sudden change in topography make it vulnerable to another of these rapid retreat periods. Although such retreats have often been documented, highly-detailed observations (e.g. frequent satellite images, time-lapse imagery) are seldom recorded.
2. Kronebreen is adjacent to Kongsvegen, both fed from the same ice field and sharing a lateral margin. Kongsvegen is slower-moving than Kronebreen, with considerably less calving activity. The difference between these two glacier is abundantly clear when looking from above at the presence of crevasses on their surfaces – there is a high density of crevasses on Kronebreen compared to the smooth surface of Kongsvegen. Recently there has been greater calving activity around the mutual margin, forming a marked embayment. This is likely to be the beginning of the separation of these two glaciers. Separations like this have not been documented closely because they happen rarely. With the changing climate though, it is highly probable that similar separations will occur at other glaciers around the world. By studying this one, we may be able to detect the initiation of the separation process in the future. For more on this separation, click here.
Time-lapse imagery acquisition is our best bet of capturing such important changes at Kronebreen. Not only do the time-lapse images offer effective visualisation of these changes, but they can also be used to extract precise, high-frequency measurements. Information on glacier velocity, calving rate, calving style, plume extent, fjord circulation patterns and surface lake estimation can be collected simultaneously. Results (and hopefully publications) will be coming from our previous years’ work soon.
The camera deployment this year would not have been possible without the support of Jack Kohler and the Norsk Polarinstitutt. Thank you Jack.
1. This AGU blog post on the initiation of glacier separation by Mauri Pelto is a concise story of the current state of Kronebreen and Kongsvegen (published October 2015).
2. Luckman et al., 2015 is a highly detailed paper on changes in velocity and calving activity at Kronebreen since 2013, in relation to tidal level and ocean temperatures. The paper also draws in other study areas around Svalbard (Tunabreen and Aavatsmarkbreen) and finds confident links between ocean temperatures and the long-term rate of calving. Small calving activity is referred to as “frontal ablation” in an attempt to distinguish it from the large, rare, catastrophic calving styles observed at Greenland and Antarctica. By differentiating the terms, the processes behind them can also be discerned and the influence of one on the other can be better distinguished. This may be a good approach to adopt for future research into calving.
3. Åström et al., 2014 is a great paper that tentatively looks at large calving events in relation to smaller calving events, likening glacier termini to self-organised critical systems which transitions between a state of instability build-up and instability release.
4. Work associated with the time-lapse sequence from Helheim Glacier, Greenland – direct observations of a large buoyant flexure calving event (Murray et al., 2015), changes in glacier surface elevation and basal crevasse propagation before the onset of this kind of calving (James et al., 2015), and modelling buoyant flexure calving (Wagner et al., 2016).
For the past month I have been in Svalbard, demonstrating on the Glaciology course (AG-325/825) at the University Centre in Svalbard (UNIS). The course is aimed at Masters and PhD students who want a taste of the Arctic, consisting of four weeks of glaciology lectures and weekly excursions to glaciers in the local area. I have been supporting the logistical side of the weekly excursions, with the odd bit of teaching here and there. The course ran very successfully and everyone seemed to thoroughly enjoy themselves. Here are a few photos from the course…
This month I have been in Svalbard, demonstrating on the Glaciology course (AG-325/825) at the University Centre in Svalbard (UNIS). The course is aimed at Masters and PhD students who want a taste of the Arctic. The course consists of four weeks of glaciology lectures and weekly excursions to glaciers in the local area. I have been supporting the logistical side of the weekly excursions, with the odd bit of teaching here and there. This week we have been to Paulabreen, a surge-type glacier, which has some impressive ice exposures.
Paulabreen is a tidewater glacier that calves into Rindersbukta, a sheltered embayment that is situated close to the small mining settlement called Svea. Bakaninbreen and Skobreen are tributary glaciers of Paulabreen. All three of these are a special type of glacier called surging glaciers. A surge-type glacier is classified by its inability to transfer its mass from the upper accumulation region to the lower ablation region in a steady way. In the quiescent phase of a surge, ice accumulates over time with slow throughput to the front (i.e. low velocities). At a given threshold, the glacier switches and rapidly transfers this large reservoir of accumulated ice, surging forward with velocities up to ten times faster than its slower, inactive phase. To find out more about surging glaciers, why they surge and where they can be found, I recommend reading a series of papers by Heidi Sevestre, whose PhD was specifically looking at surging glaciers – cataloging where they are, and producing a new concept that explains the processes behind surging dynamics.
Paulabreen and Skobreen last experienced a surge from 2003-2005, which was beautifully captured in this time-lapse sequence. The surge initiated at Skobreen, dragging Paulabreen with it as it propagated down into Rindersbukta. Over its surge period, these two glaciers advanced 2800m, with an average velocity of 3.2 m per day. For more information on the Paulabreen-Skobreen surge, click here.
Currently Paulabreen is very slow-moving and experiencing a steady retreat. The position of the glacier front is similar to its position in the 1980s, having advanced and retreated between then and now. Observations from the time-lapse sequence of the surge shows that the ice experienced thrusting and severe ice deformation, which is still seen in the ice today. By examining the ice exposures at the front of Paulabreen, we can get up close and personal to the processes that occurred during its surge phase. There are several features of interest that we could see…
Many thanks to Simon Collins (@RGSweather) for sharing his amazing photos and information about Paulabreen in the 1980s. Simon was part of an expedition who surveyed Paulabreen and Vallakrabreen, also taking sediment samples, weather readings and collecting information on the flowering species Alpine Bistort. The expedition consisted of a week-long hike from Longyearbyen to Svea, and then taking small boats across Rindersbukta to the study area. They spent six weeks there in total.
Check out RGSweather for information on the Reigate Grammar School Weather Station, an automated weather station which collects high-resolution data on temperature, rainfall, barometric pressure, humidity, wind speed, wind direction and sunshine hours in the south of the UK. RGSweather are particularly dedicated to stimulating interest in the weather, with regular blog posts and information.
Wind pockets. High-winds exploit small indentations in the ice, creating hollows in the ice face. This process is not associated with the surge at Paulabreen, but is commonly seen at ice faces all over the world.
‘Wormy’ ice. When ice is warmed by rapid motion, it partially melts. This allows air to move around the ice. It often travels towards ice crystal grain boundaries. This creates the ‘worm’-like veins in the ice. .
Regelation ice. Ice under a high amount of pressure, squeezing all air out of it to create very clear ice. Regelation ice can form at the bed of a glacier (in a high-pressure environment) or can form when exerted under high pressure. This changes the melting point of the ice and allows it to be partly liquid. During the surge at Paulabreen, sections of ice were pushed on top of one another, creating high amounts of pressure and liberating the air from the ice.
Debris entrainment features. Debris (i.e. fine-grained sediment, small pebbles, rocks) is often found in glaciers. This can be inputted on the glacier surface via rock fall and washed into surface meltwater channels. It can also be introduced at the base, entrained as the glacier ice flows over the bed. The size, texture and orientation of the debris entrainment can tell us about its origin and entrainment mechanism. At Paulabreen, we see a lot of angular debris bands, with small pebbles orientated in the same direction. In this case, the debris has been entrained from the bed as one ice section has thrust over an adjacent stationary section during the 2003-05 surge.
Debris – Regelation ice – Meteoric ice patterns. During the surge of Paulabreen, multiple sections of ice were thrust over each other as the ice was being pushed down Rindersbukta. This created a distinct pattern of debris band, regelation ice and meteoric ice. There is a gradual transition from the regelation ice to meteoric ice, from less bubbly to more bubbly ice. Where the debris passes over the ice, there is a sharp transition from meteoric ice to debris. As a section of ice is thrust over another, debris is entrained from the bed. This creates the debris band. The process of thrusting generates a large amount of pressure that transforms the ice immediately adjacent to the bed into regelation ice. This creates the seciton of regelation ice. On top of this regelation ice is normal unmodified meteoric ice, which has not been subjected to high pressure conditions. Over the period of the surge, multiple ice thrusting events create multiple lines of debris, regelated ice and meteoric ice.
Internal ice fractures. Cracks or faults in the ice that relate to cooling of the ice as it meets relatively cold winter air temperatures, and strong pressure gradients near the free ice face. These features are not directly related to the surge of Paulabreen.
Tunabreen is an ocean-terminating glacier on the west coast of Svalbard, which is special due to its unique set of dynamics. A high proportion of the glaciers in Svalbard are known as surge-type glaciers, meaning they undergo periods of fast-rate advances followed by very slow, inactive phases. Tunabreen is not only a surge-type glacier, but is one of few glaciers in Svalbard to have been observed to undergo repeated surge cycles. It has surged in 1870, 1930, 1971, and between 2002-2005. With each surge, the glacier has been advancing less and less into Tempelfjorden, as there is less mass from the upper part of the glacier to draw downwards. The glacier front advanced around 1.4km into the fjord during the recent 2002-2005 surge, compared to 3km during the 1930 surge. Pronounced ridges on the seabed at Tempelfjorden define these surge extents (Flink et al., 2015).
Much is still to be understood at Tunabreen. Little is known about what is driving the calving dynamics at the front, and what influence upglacier processes have. It is difficult to find answers from one set of data measurements, as they only investigate one portion of the active processes. For two weeks in August 2015, a collaborative fieldwork effort was made to capture data over multiple platforms:
1. The subaerial calving front of Tunabreen was surveyed using laser scanning and photogrammetry by Antonio Abellan (University of Lausanne, Switzerland) along with his students from the University of Lausanne, Switzerland. These produced fantastic profiles of the glacier front over several days.
2. Riko Noormets (UNIS) and Nina Kirchner (Stockholm University), along with UNIS PhD students Anne Flink and Oscar Fransner, were using multi-beam bathymetry, which was mounted on the front of the boat. Unlike their previous work, which primarily looks at the sea bed landform features, the multi-beam was carefully tilted to survey the subaqueous sections of the glacier front, yielding some excellent profiles and distinguished plume origins.
3. Strain meters were placed on the upper section of the glacier surface, where cracks were beginning to appear. It is hoped that these strain meters will capture crevasse propagation, which will relate to what is happening at the front of the glacier. These strain meter units were designed and built by Alberto Behar, consisting of a measurable length of wire stretched over noted cracks and secured to poles. These were installed by Doug Benn (UNIS), Chris Borstad (UNIS), Anne Flink (UNIS), Dorothée Vallot (Uppsala University), Nick Hulton (University of Edinburgh, UNIS) and myself.
4. Two custom-built quadcopters were flown over the glacier front with rapid photography capture and a laser range finder to gain overhead 3D surface elevation models. These nicely fit with the photogrammetry work on the subaerial calving front. This work was headed up by Nick Hulton (University of Edinburgh, UNIS) and Shane Rodwell (SAMS).
5. Water readings and samples were taken from the immediate fjord area to examine plume dynamics and fjord circulation patterns. This involved numerous man hours in a small zodiac boat using numerous probes to take difference water measurements. This work was lead by Kristin Schild (Dartmouth College, New Hampshire, USA), with the assistance of Doug Benn and myself. Kristin was very focused and driven to cover as much of the fjord as possible. Even the loss of a secchi disc could not de-road this work, and a new disc was made from a dvd (the film Twilight…so no big loss) and white and black electrical tape!
6. Four time-lapse cameras were installed on Ultunafjella, the ridge to the west of Tunabreen. An 85mm lens was focused on the strain meters to additionally monitor crevasse propagation and upglacier dynamics. Two cameras with 50mm lenses were placed in stereo lower down glacier, with the intention to gain stereoscopic velocities and calving rates. And finally, one camera was focused on the calving front and immediate fjord area, and set to take rapid-fire images (one every 3 seconds) to examine calving behaviours and fjord circulation dynamics over 24 hours. These camera systems were designed and produced by Nick Hulton and the University of Edinburgh School of GeoSciences workshop, and installed by Doug Benn and myself, with the help of Anne Flink, Chris Borstad, Dorothée Vallot and Kristin Schild.
The fieldwork was undertaken over the course of two weeks in August. Unlike in the winter where we can access Tunabreen via snow scooter, the glacier has to be accessed via boat in the summer. Our boat was UNIS’ own, the Viking Explorer, which is a small converted fishing boat with 4 beds. For 2 weeks, we slept, ate and worked on/from the boat (I slept under the kitchen table one week, and under the skipper’s chair the next week… which was surprisingly not as uncomfortable as you might think!) We spent 3 nights moored in Tempelfjorden for the first week, and 5 nights in the second. This was the easiest way to access the glacier on a daily basis.
Access to the glacier and the ridge each day involved long hikes in with heavy packs of equipment. Minor teething problems with the strain meters meant it took us three days in total to install the seven strain meters, drilling poles into the ice and mounting the meters onto them. The ridge that the cameras were installed on took approximately four hours to climb, which we accessed via Brucebreen, a small valley glacier which is situated on the other side of the ridge and Tunabreen. This site was re-visited in the second week to check each camera was working and change the timing of the camera on the calving front from 3 seconds to 10 minutes.
As well as provide better understanding of the dynamics at Tunabreen, it is hoped that this data will also be used as a more realistic domain for mathematical modelling. Early results from the time-lapse installations have given valuable data about the fjord circulation patterns, and there is excited talk of extending our rapid-fire time-lapse applications. It is hoped that the surface model representations from the UAV, laser surveying, photogrammetry and bathymetry work can all be used together to create a complete three-dimensional reconstruction of the glacier front (subaqueous and subaerial). Results so far look very promising.
The general consensus is that this work is something very special. The collaborative effort by all makes this work so rewarding, and being able to bounce ideas off a large group from different academic backgrounds is exciting. I personally feel that the involvement of others and their encouragement makes such fieldwork so much more enjoyable than going it alone.
With thanks to our skippers, Kenneth and Lars Frode, for making this fieldwork possible.
Flink et al. (2015)
– Work from UNIS on surveying the sea bed of Tempelfjorden using multi-beam bathymetry, which revealed past surging extents
Sevestre and Benn (2015)
– A new record of surge-type glaciers in the world along with a new uniting theory that explains their distribution – the enthalpy cycle model