CR
Cryospheric Sciences

Cryospheric Sciences

The bi-polar behaviour of surge-type glaciers – Heidi Sevestre

The bi-polar behaviour of surge-type glaciers – Heidi Sevestre

Surge-type glaciers are the bi-polar member of the family of glacier dynamics. Every now and then they go into a complete fury and nobody really understands why.

What are surge-type glaciers?
Surge-type glaciers typically go through what we call the “surge cycle”. It is divided into two phases; a long quiescent phase during which the glacier is more or less dormant, followed by much shorter phase called “the surge”. Glacier velocities during the surge can typically reach 100 to 1000 the quiescence velocities. Velocities of up to 40 m per day were measured in Alaska during the surge of Variegated glacier.
The duration of the surge cycle varies from region to region. It tends to average around 20 years in Alaska, and 100 years or more in the Arctic.

What really triggers the surge of glaciers has always been an enigma in glaciology. Their unpredictable behaviour, and the dramatic and dangerous nature of the surge phase have always prevented extensive fieldwork to collect much needed in-situ data. Only a handful of studies have managed to obtain field data on glaciers before, during and after the surge of a glacier.

Distribution of surge-type glaciers in the world. Normal glaciers are blue, surge-type glaciers are represented by pink dots (credits: Sevestre and Benn, submitted)

Distribution of surge-type glaciers in the world. Normal glaciers are blue, surge-type glaciers are represented by pink dots (credits: Sevestre and Benn, submitted)

Where are they found?
Surge-type glaciers are distributed in a “non-random” fashion, meaning that they do not uniformly pepper all the glacierized regions on Earth, but contrarily gather in narrow clusters only found in some regions. We think that cracking the code of their distribution might lead us to a better understanding of the causes of surging.
A strong concentration of surge-type glaciers can be found in the sub- and high-Arctic, namely Alaska, Arctic Canada, Greenland, Iceland, Svalbard, Novaya Zemlya and Karakoram. Another popular area for these glaciers is western central Asia with the Karakoram, Tian Shan and Pamirs. Sporadic clusters of a few individuals have also been identified in the Andes, Caucasus and Kamchatka (See Fig. 1).

Our contribution to the question:
A large part of our work has consisted in building a global inventory of all observed/identified surge-type glaciers in the world. This has enabled us to perform the first global statistical analyses on these glaciers. Comparing the geometry and climatic distribution between normal and surge-type glaciers has yield very interesting results.

Fieldwork has also been an essential component of our work. As a group fully based in Svalbard, we have no excuses not to do get out in the field and collect top quality data. Svalbard is actually of huge interest for us as the population of identified surge-type glaciers represent 20% of all the glaciers on the archipelago.

By using a Ground Penetrating Radar (GPR) we have been able to look at glacier thickness and ice temperature on 15 different surge-type glaciers. These attributes are essential to map the thermal structure of the glaciers and understand further their potential surge mechanisms. As extensive as this may sounds, GPR-ing glaciers in Svalbard is actually quite an enjoyable task to do as the whole system can be towed by a snow scooter, and hundreds of kilometres of data can be collected in just a couple of days (see figure 2).

An “all seeing eye” is our best ally to observe spatial patterns of surging on the archipelago. Remote sensing data is really the only way we can catch surges in their very early stages. At the end of last year, we acquired pairs of TerraSar-X images covering most of the archipelago, and derived surface velocities from there. We discovered that no less than 17 glaciers are currently actively surging!

Driving in straight lines on a glacier in Svalbard = collecting GPR data (credits: Nick Hulton).

Driving in straight lines on a glacier in Svalbard = collecting GPR data (credits: Nick Hulton).

So… why do they surge?
First, we know how glaciers can surge. They can sustain such high velocities over months or years by having water at their base, lubricating their movement. But as soon as the water escapes, the surge terminates.
Over the past decades, two models of surging have been developed, each trying to understand how glaciers with different thermal structures can surge. Glaciers can either be “warm bedded” meaning that ice at their base is just at the point of melting; or “cold-bedded” if their ice is below the point of melting. Glaciers with a fully warm base have been observed to surge, as well as glaciers with a warm core surrounded by cold ice. The first model suppose that a switch in the configuration of the basal meltwater drainage system could lead to a surge, while the second suggests that surging could be caused by a change in the basal temperature from cold to warm. In both models, water eventually becomes trapped under the glacier, removing any friction at its base, and enabling it so move at high speeds.
There is still a lot to understand about these glaciers, and we hope that our results will cast a new light on the weird and wonderful world of surging glaciers!

Time lapse imagery

Follow this link to see a time lapse of the surge of Paulabreen, Svalbard:

http://www.polarresearch.net/index.php/polar/rt/suppFiles/11106/0


Heidi Sevestre is a PhD student based at the University Centre in Svalbard and supervised by Prof. Doug Benn and Prof. Jon Ove Hagen. Heidi is interested in glacier dynamics, particularly the mechanisms of glacier surges. She studies the global distribution of surging glaciers and their regional specificities, while field data is collected in Svalbard.

Heidi tweets as @HeidiSevestre.

­Around the Poles in approx. 100 minutes: Earth Observation for Climate Science and the Cryosphere – Anna Maria Trofaier and Anne Stefaniak

­Around the Poles in approx. 100 minutes: Earth Observation for Climate Science and the Cryosphere – Anna Maria Trofaier and Anne Stefaniak

Everyday we come into contact with technology that has changed the way we work, live and even think. Yet it is still easy to forget how integral satellite technology is to our daily lives; over two thousand artificial satellites currently orbit our planet – satellites for navigation, for telecommunication, for meteorology, and for environmental and climate monitoring. The latter two categories fall within the field of Earth Observation (EO). These satellites follow either Geostationary Orbits (GEOs) or Low Earth Orbits (LEOs). LEO satellites zoom around the globe, taking just over 1.5 hours to complete a cycle, collecting data crucial to our understanding of the Earth and its climate system. Parameters that represent the characteristics of the climate system are called Essential Climate Variables (ECVs) and in order to be able to monitor a changing climate we need to create long-term, global ECV records. Establishing these archives is our mission! In 2010 the Global Climate Observing System (GCOS), in support of the UN Framework Convention on Climate Change (UNFCCC), identified 50 ECVs. Out of these 50, 13 ECVs – those that currently are technically feasible to observe from space, that were not already covered by existing projects, and for which the European Space Agency (ESA) could provide a unique and significant contribution to the scientific community – have been selected and incorporated in 15 projects; this is the ESA Climate Change Initiative (CCI).

Focus on cryosphere

We all know the cryosphere is strongly linked to climate, contributing to the Earth’s thermal inertia. The cryosphere is a climate driver, and at the same time it is also an indicator of climate change; the cryosphere interacts with the climate system and reacts to changes in climate. Take for instance the populist example of a climate change indicator: Ice melt and associated global sea level rise. The magnitude of global and regional sea level change, and hence their consequences, need to be further explored by research such as glacier and ice sheet mass balance studies. In order to adapt to the effects of a changing cryosphere, we need to monitor the frozen parts of our world closely.

This is where the ESA CCI may provide some valuable data for your own research. Currently, there are four CCI projects specifically dedicated to the cryosphere (although there are others that are linked to cryospheric research such as ‘Sea Level’ and ‘Sea Surface Temperature’). These four cryosphere CCI projects are: ‘Glaciers’ , ‘Ice Sheets Greenland’, ‘Sea Ice’ and the new project ‘Ice Sheets Antarctica’, which will complement the original ‘Ice Sheets Greenland’ project.

View of East Greenland fjord

Photo credit: Nanna B. Karlsson

 

Developing useful data products, what’s new?

ESA has always tried to engage the scientific community (e.g. through its Data User Element (DUE) and Support To Science Element (STSE) ), encouraging input on identifying essential EO products and organising workshops that further communication amongst the – shall we call them – producers and users. However, this process is not always straightforward. In the past, it has often been the case that EO products do not appeal to potential user communities. Products are developed which are then not exploited because they do not represent the appropriate phenomenon, at the appropriate scale or with only limited consistency (the issue of frequent, consistent, comparable data being ever present). It is as if EO scientists, field scientists and modellers speak fundamentally different languages. The CCI projects have therefore been specifically designed with climate scientists in mind, centrally involving the climate community in each project. Requirements of the user communities were rigorously assessed and incorporated in the products’ development, and in addition a separate CCI project wholly dedicated to climate modelling, the ‘Climate Modelling User Group (CMUG)’, was set up.

 

Research at the ESA Climate Office

Apart from providing these data products we also do some of our own research. An example of a current study is an analysis of Arctic sea ice in relation to El Niño events. CCI datasets including Arctic sea ice concentration and thickness variables enable research to be carried out into the major influences of climate variability. We know that the Arctic sea ice trend is steadily decreasing annually but the effect of inter-annual climate variability is less well constrained. Using the CCI Sea Surface Temperature (SST) datasets, one of the most direct climate links of El Niño, correlations with sea ice can be investigated. El Niño events originate in the tropical Pacific with warmer temperatures affecting the global climate. These changes can be traced through the ECVs allowing us to determine the time it takes for it to affect global climate and in particular, Arctic sea ice. By establishing how inter-annual global climate variability influences sea ice, we can aid predictions of future events. EO satellites help provide some of the most globally comprehensive climate records, significantly aiding our understanding and adaptation to these climatic changes.

The CCI datasets provide climate records for a range of ECVs. However, cryospheric research is not simply limited to the above-mentioned CCI projects. Further research at the Climate Office focuses on using some of the land-based climate variables (including fire, land cover and soil moisture) as proxies for permafrost monitoring. Permafrost is an aspect of the cryosphere that cannot be directly monitored from space, but the development of proxies will support global scale monitoring, crucial to understanding changes in permafrost conditions.

EO has already, and continues to make significant changes to the way we investigate and gather new information about the planet we live on. However, there is still much that we do not yet know and hope to discover with the on-going monitoring of ECVs. As the products are updated to include more recent data, developing long-term records, our ability to decipher climate patterns and responses will be significantly aided.

 

Our changing planet

Nature is in a state of flux. We monitor our ever-changing world so we can understand the underlying processes. Our motivations may be economic or altruistic; they may be due to ambition or a thirst for knowledge. However, one thing is certain, the impacts of climate change will affect us all. Satellites help provide us with the bigger picture. Producing the ECV archives is one step towards effective monitoring in support of the international climate change community.

There are many words that describe Earth from space: unique, beautiful, vulnerable, alive – they all fit the bill. A recent ESA mission to the International Space Station was named Blue Dot; a rather fitting description of our place in the universe. In Jules Verne’s classic, the debate about how long it takes to journey around the world starts off with the quote: “The world has grown smaller, since a man can now go round it ten times more quickly than a hundred years ago.” Today LEO satellites orbit the world about 15 times per day with a repeat cycle of 12 days – that’s nearly seven times faster than Phileas Fogg’s record. The world has not grown smaller, but in fact the world that we see is vast and – to a degree – still unknown. Whatever your Weltanschauung, your perceptions of the world, your motivations and reasons for undertaking research, ultimately we monitor our planet for the benefit of society and the environment. Together, let us try to understand our planet and its climate system better!

 

To access any of the ESA CCI datasets please visit our website at http://www.esa-cci.org/ and click on the download link on the individual project sites. Registration is required but all data are free of charge and we welcome any comments with regard to use of the data.

 

Anna Maria Trofaier is a Postdoctoral Research Fellow and Anne Stefaniak is a Young Graduate Trainee working for the European Space Agency’s Climate Office at the European Centre for Space Applications and Telecommunications (ECSAT) on the Harwell-Oxford Campus in the UK.

You can follow them on Twitter @WhinnyHowe, @AnneStefaniak and @esaclimate.

 

This approximation is for Copernicus. LEO cycles can be anywhere between 1 – 2 hours depending on altitude.

4 Reasons Why You Should Get Involved as an Early Career Scientist (& a caveat) – Allen Pope

4 Reasons Why You Should Get Involved as an Early Career Scientist (& a caveat) – Allen Pope

You’re an early career scientist (ECS), or maybe you mentor one. So you know that we ECS are busy people, with responsibilities ranging from coursework to teaching, research to outreach, and labwork to fieldwork. And now there is this listicle (no, I’m not embarrassed about choosing this format) telling you to make time in your already packed day to volunteer some of your time to a(n early career) professional organization. Please, take a moment to hear me out.

When I was working on my master’s degree, I saw a workshop that I really wanted to attend, but I knew that similar previous events had been over-subscribed. So, I figured the best way to make sure I had a spot was to help organize the event myself. I enjoyed it and saw how much benefit both the attendees and myself got from the whole process. So, one thing led to another and eventually I became president of the Association of Polar Early Career Scientists, an organization created by ECS for ECS to be able to stimulate interdisciplinary and international research collaborations, and develop effective future leaders in polar research, education and outreach. Involvement with APECS transitioned to being one of the first elected early career members of the Council of the American Geophysical Union. Despite the time investment, these opportunities have been very valuable to me, so let me tell you why I (as an ECS) have gotten and continue to be involved in (early career) professional organizations.

Inukshuks

1) Networking & Building Connections

Networking doesn’t have to be a dirty word – really, it’s just meeting new people (choose your favorite way), finding shared interests, and keeping in touch with colleagues. Normally, people think of networking as just for extroverts – but there are ways to make it work for introverts, too.

Getting involved with a professional organization can be the key to making friends in your field and having conference buddies no matter where you go in the world. You can practice your networking skills with other ECS: share stories, grab a drink, find out about training courses or job opportunities, and build a support network. The shared mission of your volunteering will help bring you together.

And, if that weren’t enough, getting involved with a(n early career) professional organization can be the key – or the excuse – to meet that rock star scientist whose papers you’ve read. Except you’re not just a fan – you’re a colleague with a reason to interact. Take advantage of this for all it’s worth!

Taku A & the crew

2) Gaining Skills & Experience

There are so many things that volunteering for a(n early career) professional society can teach you. Leadership, running a meeting, building consensus, motivating a team, facilitating discussion, organizing an event, asking for funding, building a newsletter, communicating to diverse audiences – and the list goes on. Whether you bring it back to your research career (running a lab group takes a lot more skills than MATLAB), or discover that you have a knack and love for research coordination and decide to change career tracks, you come out on top by getting involved.

 

3) Practice Taking Initiative

Making things happen is satisfying and fun, pIMG_8985articularly when you’re in a field where results take years to come to fruition (if ever). No matter what career path you take, having the ability to be  “do-er” will be helpful. Being on some committees can help you achieve this – and being on others (in a good organization) will give you faith that recommendations put forwards by committees that only seem to provide advice are actually acted on and executed in meaningful ways.

Use your experience and expertise to go from talk to action – following through on meaningful contributions will get you noticed and allow you to continue to build and progress. But make sure that you’re choosing activities that are beneficial to you, too. As an ECS, you owe it to yourself to build skills and connections that you find fulfilling and that will contribute to your future career. Volunteering your time should always be a win-win situation for both you and the team you are working with.

4) Balance and Time Management

While your thesis or pushing out that next paper might seem like the only important thing right now, it won’t be forever. As you continue to grow in your career, multiple projects, proposals, reviews, etc. etc. will begin to pile up – and you’ll wish you had gained more experience handling the workload earlier on.

By getting involved in a professional organization as an ECS, you are getting an early start on training yourself to maintain a work-life balance. You will learn to prioritize what you need to get done and when. You will learn to balance your own time with other peoples’ schedules (both are valuable). You will also learn the importance of everybody knowing what time zone a conference call is on. Getting a thesis puppy might not be right for you, but having something that isn’t just your primary research can be healthy, gratifying, and productive all at the same time.

A Caveat: It’s all about the continuum.

“Getting involved” means different things for different groups – check out your options, put yourself out there, and find out what works for you. Whichever group you choose to get involved with (and I mention a few ideas below), a very important thing to keep in mind is that you want to interact with not only other ECS, but also experienced colleagues who will be able to mentor and guide you. Even ECS organizations should include not-so-early-career-scientists in as many ways as possible, bringing together a continuum and transferring knowledge, rather than reinventing the wheel.

There are many organizations you can get involved with as an ECS, whether it is an early-career specific group (like APECS, PYRN, or ICYS) or a larger international body (like EGU, AGU, IASC, etc.). You could “just” co-convene a session at a conference you are planning on attending (with other ECS or an experienced colleague), organize a discussion group or mentor panel in your department or at a regional meeting, or even set up a pub meet-up sometime. It’s all getting involved in your community: networking, building skills, taking initiative, and balancing your priorities.

OLYMPUS DIGITAL CAMERA

Allen Pope is a postdoc working at NSIDC and UW’s PSC, studying snow and ice, mostly from space. He tweets about the cryosphere, remote sensing, and few other things @PopePolar. Find out more about his research and what other projects he’s involved in at about.me/allenpope. The photos accompanying this blog entry are also by Allen.

My drone summer – Johnny Ryan

My drone summer – Johnny Ryan

In the summer of 2014, our group at Aberystwyth University and the University of Cambridge decided to pursue an ambitious but exciting field campaign in West Greenland. The aim was to survey Store Glacier once a day using a fixed-wing unmanned aerial vehicle (UAV) (see photo above for a view from the UAV on its way back from a mission with Store Glacier, West Greenland in the background). The UAV is equipped with a digital camera, which takes photos every two seconds during its dangerous 40 km sortie over the glacier. These photos can be stitched together using multi-view stereophotogrammetry to produce high-resolution orthoimages and digital elevation models of the glacier. We hope to use the data to provide insights into the process of calving and the interplay between the glacier and sea-ice mélange that forms during the winter and breaks up in late spring.

A) Landsat 8 true colour image of Store Glacier in August 2014 with the location of camp site. B) MODIS mosaic image of Greenland (Kargel et al., 2012, The Cryosphere) with location of Store Glacier which is situated in Uummannaq Bay.

A) Landsat 8 true colour image of Store Glacier in August 2014 with the location of camp site. B) MODIS mosaic image of Greenland (Kargel et al., 2012, The Cryosphere) with location of Store Glacier which is situated in Uummannaq Bay.

The field campaign started on 7th May 2014 when my colleague, Nick Toberg, and I were dropped off by a helicopter on a peninsula by side of Store Glacier. This site was to be our home for the next 10 weeks and as we watched the helicopter disappear down the fjord, there were not two lonelier men on Earth. Temperatures dropped quickly to -20 degrees as the sun set behind the mountains so it was important to set up camp and prepare for a chilly first night. We were well provided for, with a large mess/science dome tent, individual sleeping tents, generators, a stove, kerosene heaters and a table and camping chairs. By the 9th May we were ready to start flying missions over Store Glacier.

 

The camp with sleeping tents and mess/science tent. Generators and solar panels were used to charge laptops and UAV LiPo batteries.

The camp with sleeping tents and mess/science tent. Generators and solar panels were used to charge laptops and UAV LiPo batteries.

A typical day would consist of a lazy breakfast, followed by some reading or hiking during the morning. We would then have lunch and aim to fly the UAV at 3pm. Setting up the UAV took a few minutes and a typical survey would take 30 minutes. At the start of the field campaign, these 30 minutes would seem like a lifetime and we would usually be too worried and agitated to think of anything but the plane. I would pace up and down trying to remember whether I had checked a certain part or become increasingly nervous about the wind speed, which always seemed to increase as the plane started its mission. As time passed and more data was collected, we became more and more relaxed. We got to a point where, once the UAV was launched, we would go straight back into the mess tent and read our books. Then once, we heard the plane over our heads, we would head out and land it.

Inside the mess tent. Downloading the GPS, attitude and the locations of the camera triggers from the flight controller.

Inside the mess tent. Downloading the GPS, attitude and the locations of the camera triggers from the flight controller.

Once the plane was safely landed (see video below), which was difficult on the short, boulder-strewn runway, the photos would be downloaded from the SD card and the log files from the flight controller (see photo above). We would then check for damage and repair anything that needed fixing. Cooking and washing up duties were rotated every evening and we would watch a film (usually something starring Nick Cage) after dinner. After the film, we would head to our individual sleeping tents. There was something magical about brushing your teeth overlooking Store Glacier below, the Greenland Ice Sheet to the east and the beautiful fjord and rugged mountains to the west.

In total we completed 55 surveys of Store Glacier from early May to late July. Nick and I are still friends and are now processing the data. We hope to be able to provide some exciting results soon.

 

Johnny Ryan is a PhD student working at Aberystwyth University in Wales and is supervised by Prof. Alun Hubbard. He is interested in understanding the dynamics of the Greenland Ice Sheet and its fast flowing tidewater outlet glaciers. The primary tool Johnny uses for his research is a fixed-wing unmanned aerial vehicle (UAV) which can be used to survey the cryosphere at fine temporal and spatial scales. Currently he is using data collected by UAVs combined with timelapse camera imagery, meterological stations and tide gauges to investigate processes that control calving and the break-up of the ice melangé at Store Glacier. Johnny tweets as @glaciology_uavs .

 

Welcome!

Welcome!

Hello and welcome to the blog of the EGU Cryosphere Division.

This blog aims to spread the enthusiasm for ice in all its forms – from snow, glaciers and ice sheets, to ice crystals, extra-terrestrial ice bodies and isotopic ice composition.

The blog will feature stories related to cryospheric research, particularly the latest in fieldwork programmes, research projects and scientific results. With the help of beautiful imagery and riveting tales of hardships (or at least tales of cold conditions), we hope to inspire interest in the role of ice in our climate system.

The editor of the blog is Nanna B. Karlsson, the Young Scientist representative of the EGU Cryosphere Division. Researchers from the cryospheric community will contribute with content, making sure that the blog entries highlight the exciting and thrilling research projects that are engaging us at present.

The first blog entry will be from Johnny Ryan (Aberystwyth University, UK), who will write about his work with UAVs (Unmanned Aerial Vehicles) in Greenland. This is promising be an exciting insight into a new technique in glaciological fieldwork.

Next year there will be entries in a variety of subjects within the cryospheric field. We hope to take you to the world’s northernmost research institution in Svalbard, where Heidi Sevestre is conducting her research. We will go on an expedition with a wooden schooner to the fjords of Southern Greenland with Anne-Katrine Faber and Malte N. Winther (University of Copenhagen, Denmark). Eva Huintjes (RWTH Aachen University) will take us even further afield to the Tibetan Plateau where she conducted her PhD research. And Alexandra Messerli (University of Copenhagen, Denmark) will show us what is happening at the bed of a glacier when the melt season starts. All very exciting stuff – and lots more to come!

If you would like to write a blog entry about your research, please get in touch with the editor, especially if you are a young scientist! We welcome all contributions that fit broadly within the topic of cryospheric research.