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Image of the Week – Powering up the ground in the search for ice

Electric Resistivity Tomography profile of the north-facing slope of the Rohrbachstein in canton Bern, Switzerland [Credit: Laura Helene Rasmussen].

In an earlier post, we talked briefly about below-ground ice and the consequences of its disappearing. However, to estimate the consequences of disappearing ground ice, one has to know that there actually is ice in the area of study. How much ice is there – and where is it? As the name suggests, below-ground ice is not so easy to spot with the naked eye. Using geophysical methods, however, it is possible to obtain a good idea of the presence and whereabouts of ground ice, and of frozen ground, in an area of interest.


Looking for ice

Before starting a geophysical survey, which requires instrumentation and time, you might want to take a look at your area of interest and estimate, whether ice presence is even an option. The first indicator is temperature, which has to be in the favor of permafrost presence. Other indicators for presence are surface features such as mounds that could be caused by considerable frost heave, lobes perpendicular to the slope and front angles exceeding the critical angle of repose. They can indicate that ice has had an influence on the geomorphology in the area.

If you suspect ground ice in your area of interest, and you want to confirm or rule out your suspicion as well as investigate the extent of the ice, you might consider doing a geophysical survey. There are a few useful inherent properties of ice that make it possible to distinguish it from rock, air or water. These properties will determine the choice of geophysical methods to use. This week, we will illustrate two methods which, when combined, can be useful tools for determining ground ice presence or absence. The test subject is an area of suspected frozen ground just below 3000 m altitude – the Rohrbachstein in canton Bern, Switzerland.

Electrical resistivity tomography

In an electrical resistivity tomography (ERT) survey, we measure the potential difference (ΔU) of a material, over a given distance, when applied with a certain current strength (I). From the fact that resistance is computed by dividing U by I, the electrical resistivity of the material can be estimated. The resistivity can be seen as the reciprocal of the material’s electrical conductivity and is measured in mΩ. Practically, an array of electrodes are placed in the ground with a certain spacing and a certain length of the profile. The spacing and length of the profile determine the resolution and penetration depth. All electrodes are then connected with a cable to each other and to the instrument, which works as both a voltmeter and a source of current. Then, systematic measurements of potential difference can be conducted throughout the whole profile.

Water has an electrical resistivity of 10-100 mΩ, whereas ground ice has a resistivity of 103 to 106 mΩ. This makes this method practical for distinguishing liquid from frozen water in permafrost areas. The resistivity of rock is between 102 to 105 mΩ, and the resistivity of sediment depends on the mixture of rock, water, ice and air. Air has an extremely high resistivity, which should be easy to point out, but since below-ground material is mostly a mixture of all the mentioned components, things are very often more blurry. What one actually looks for in the measurements is areas of higher, lower and in-between electrical resistivity values. An example of such a case is displayed in our Image of the Week.

Our Image of the Week shows the resistivity profile of a slope at just below 3000 m altitude in the Bernese Alps, Switzerland. For comparison, the same slope is shown in a normal photo in Fig. 2 (not to scale). Blue colours mark high resistivities, red mark low, and green mark somewhere in between. From this profile, we might conclude that the upper layers of the lower slope are moist and underlain by bedrock (red and green, respectively, whereas the upper slope seems to be moist below an area of high resistivity (red below green-blue). Additionally, there is a significant feature of high resistivity in the middle of the slope. This slope could contain ice in those blue areas. However, the high resistivities could also be caused by air volume in this blocky site. To be certain, we can use an additional method.

Fig. 2: Photo of the north-facing slope of the Rohrbachstein in canton Bern, Switzerland. The photo was taken facing east and shows the upper part of the slope analyzed with ERT and seismic refraction, but is not to scale compared with the Image of the Week and Fig.4 [Credit: Laura Helene Rasmussen].

Seismic refraction analysis

To distinguish air from ice, we can do a survey of the subsurface using seismic refraction analysis. Seismic refraction surveys use the fact that the speed (in ms-1) of sound wave propagation is different through different materials. The speed is estimated by placing geophones in a profile line and creating a sound wave by hitting the ground with a sledgehammer in between them (Fig. 3). The geophones detect the sound wave from this hammer blow one by one as it travels through the subsurface, and the time it takes for each geophone to receive the signal is noted. This allows us to calculate the seismic (sound) velocity from the distance and travel time. Different layers in the subsurface with different properties, and thus different seismic velocities, will cause the sound wave arriving at their surface to be refracted with different delay compared to the direct wave (which travels straight from the hammer to each geophone), and that fact can reveal properties of below-ground material.

Fig. 3: Hammer-swinging doing a seismic refraction profile [Credit: Hanne Hendricks].

The advantage of this method for ground ice studies is that ice has a seismic velocity of about 3000 ms-1, whereas sound waves move through air with only 330 ms-1. Thus, a rough profile of that same slope from our Image of the Week and Fig. 2 using seismic refraction geophysics looks like Fig. 4.

In this profile, red colours denote high seismic velocities and blue colours are very low seismic velocities. The high-resistivity feature in the middle of the ERT profile at about 3-4 m depth, which could contain air or ice, would cause red-purple colours (high velocities) if the feature contained ice, and blue colours (low velocities), if it was air volume. As seen from Fig. 4, colours at depths are reddish and certainly not blue, which makes it likely that the ERT feature at 3-4 m depth is actually an ice body. The high-resistivity area in the surface layers of the upper profile, however, corresponds to the blue colours in this seismic refraction profile, and with high resistivity, but low seismic velocity, this area is most likely air volume and not ground ice.

Fig. 4: Seismic refraction profile of the north-facing slope of the Rohrbachstein in canton Bern, Switzerland [Credit: Laura Helene Rasmussen].

The method depends on the setting

Ground ice does, obviously, come in different forms in different environments, and so the methodological considerations when using geophysical techniques vary in different settings. In this case, we look for ice in a blocky slope. That type of setting presents challenges such as contact problems between sensors and the ground, which can impede the measurements. That issue would not worry a scientist mapping ground ice in a moist Arctic lowland site. The lowland scientist might, however, have to consider resolution issues or salt content in her soil solution when evaluating the results. Perhaps she wants to combine with yet other methods such as drilling permafrost cores for detailed information on ice- and sediment type. As non-destructive methods, covering relatively large spatial areas without having to get a drill rig to the high mountains or a remote Arctic area, however, geophysics can be a good option for ground ice detection.

Further reading


Laura Helene Rasmussen is a Danish permafrost scientist working at the Center for Permafrost, University of Copenhagen. She has spent many seasons in Greenland, working with the Greenland Ecosystem Monitoring Programme and is interested in Arctic soils as an ecosystem component, their climate sensitivity, functioning and simply understanding what goes on below.

Image of the Week – ROVing in the deep…

Aggregates of sea ice algae seen from the ocean below by the ROV [Credit: Katlein et al. (2017)].

Robotics has revolutionised ocean observation, allowing for regular high resolution measurements even in remote locations or harsh conditions. But the ice-covered regions remain undersampled, especially the ice-ocean interface, as it is still too risky and complex to pilot instruments in this area. This is why it is exactly the area of interest of the paper from which our Image of the week is taken from!


This is sea ice… seen from the ocean

Traditionally, only divers (and maybe seals, fish, krill, belugas, etc.) have been able to see what is happening just under the sea ice, in the ocean. That is no routine activity – I personally have not been in a fieldwork campaign involving a diver. It is extremely dangerous to dive in such cold waters, and the diver is limited to a small area around the entry hole, which might refreeze really fast. The most common method is to drill small holes from the top of the sea ice to the ice-ocean interface at specific locations instead, and collect the bottom of the resulting ice core. There are obvious problems with this method:

  • drilling takes a lot of time and effort;
  • you cannot drill everywhere, since it becomes unsafe if the ice is too thin (you still have to be standing on the ice to do the drilling);
  • the location of your core has to be representative of what you are sampling.

This is why researchers are trying to more often use sea robots, which can take measurements over a large area while the researchers are safe somewhere else. But most robots that are now used to monitor the ocean are not adapted to ice-covered regions, and the few that are require a lot of specifically trained technicians to operate them and/or can only perform very specific tasks.

Our Image of the Week was taken by a new robot, “The Beast”, whose specificities are described in the recently published Katlein et al. (2017). In brief, it is ice-resistant, small, very manoeuvrable, can be operated by only one or two people from a cosy hut on the ice, and contains any possible sensor you can think of (even a small water bottle for sampling, and a net). It belongs to the family of Remotely Operated Vehicles (ROV), which means that it is connected to the operator by a cable – if anything goes wrong under the ice, just pull on the leash!

And thanks to ROVs, we can see (e.g. on this Image of the Week) that the thickness of the sea ice, hence the amount of light that goes through it and the whole sympagic communities vary a lot over small regions.

What the pilot sees when driving the ROV by a sea ice pressure ridge [Credit: Katlein et al. (2017)].

Why do we need such observations?

  1. Robustness: it will not totally replace the traditional ice coring, for some studies still need to get the actual ice. But it will ensure that the choice of locations make sense, or help extrapolate the localised coring results to a larger region.
  2. Validation: for basin-wide studies, we need satellites. But satellite retrievals, especially those for sea ice thickness, still need in-situ measurements for validation. ROVs can provide more validation points than traditional point-coring for the same mission duration, hence ultimately improving algorithms.
  3. Seeing is believing: for anything from outreach to future fieldwork preparation, videos captured by an ROV are an unvaluable tool. Ecologists can even see which species live there (or discover new ones).

 

Further reading

Edited by Clara Burgard

Image of the Week – Bioalbedo: algae darken the Greenland Ice Sheet

Image of the Week – Bioalbedo: algae darken the Greenland Ice Sheet

Most of the energy that drives glacier melting comes directly from sunlight, with the amount of melting critically dependent on the amount of solar energy absorbed compared to that reflected back into the atmosphere. The amount of solar energy that is reflected by a surface without being absorbed is called the albedo. A low albedo surface absorbs more of the energy that hits it compared to a high albedo surface. Our Image of the Week shows patches of dark grey-brown algal blooms on the Greenland Ice Sheet, giving the surface a surprisingly low albedo.


The colour of ice

Clean ice and snow are among the most reflective natural materials on Earth’s surface making them important ‘coolers’ in Earth’s climate system. The term ‘albedo’ describes how effectively a material absorbs or reflects incoming solar energy – it is the ratio of downwelling light arriving at a surface to the amount of upwelling light leaving it. The albedo of fresh, clean snow can be as high as 90%, meaning that out of all the solar energy reaching the surface only 10% is absorbed. However, the albedo of ice and snow can vary widely. This is important because the albedo determines how much of the incoming solar energy is retained within the snow or ice and used to raise the temperature or drive melting. It therefore controls snow and ice energy balance to a large extent.

There are several reasons why the albedo of snow and ice can vary. First, once ice crystals begin to melt they lose their delicate structures that efficiently scatter light and develop rounded granular shapes. Meltwater generated by snow or ice melt fills the gaps between the grains, promoting forward scattering of light deeper into the ice, rather than scattering back towards the surface. This increases the distance travelled through media where absorption can occur, and therefore lowers the albedo as the light is less likely to escape the material after it enters. The more melt, the greater this effect. Second, other materials such as dust or rock debris can enter the snow or ice. These ‘impurities’ generally absorb light more effectively than the ice crystals themselves and therefore reduce the albedo. However, this depends upon their concentration, optical properties and proximity to the surface. Additionally, whether the impurities are inside or outside the ice crystals, where on the planet the material is and the time of day are also important.

Any impurity that darkens a mass of ice or snow increases the amount of solar energy absorbed compared to when the material is impurity-free. This means that impurities promote melting, which is in itself an albedo reducing process. Therefore, the impact of impurities on albedo is non-linear and greater than the direct effect of their absorption alone. There are many different impurities that commonly lower the albedo of ice and snow, including mineral dusts and black carbon (e.g. from fossil fuel combustion). However, there is also a growing literature on another form of impurity that darkens ice and snow on glaciers and ice sheets on both hemispheres: biological growth (also see this previous post). Algae are the primary biological albedo-reducers on ice and snow. Photosynthetic microalgae bloom on the surface where light is abundant, which provides them with energy that they use to turn carbon dioxide and water into sugars. This in turn provides food for other microorganisms. In doing so, they darken the ice surface simply because the algal cells are more effective absorbers than the ice crystals. However, as the algae become exposed to increasing light intensities, they produce pigments that act as sun shields, protecting their cellular machinery from the damaging effects of too much light. This effect enhances the biological darkening and increases the energy absorbed within the snow or ice.

Biological darkening

There are several distinct microbial habitats on glaciers and ice sheets. Snow algae are a feature of melting snowpacks that colour snow surfaces green early in the year and red later because prolonged exposure to sunlight causes them to produce red ‘sunscreen’ pigments (see this previous post). Their influence on snow albedo has yet to be determined, although they have been shown to change the amount of visible light reflected from the surface (Lutz et al., 2014) and in Antarctica they have been shown to influence light absorption at depth within the snowpack (Hodson et al., 2017). Some bacteria have been identified feeding upon the algae, and the algal blooms also provide food for red coloured ice worms. This is probably why, in ‘The History of Animals’, Aristotle wrongly attributed the red discoloration of patches of snow to red worms rather than pigmented algae!

Fig. 2: (a) Albedo for clean snow, bare ice and ice with an algal bloom measured on the Greenland Ice Sheet in July 2017. (b) Microscope image of melted surface ice from the Greenland ice sheet. The red oval shaped particles are ice algae and the angular, clear particles are mineral dust fragments. [Credit: A: J. Cook, B: C. Williamson]

On ice, a different species of algae exists in a thin liquid water film on the upper surface of melting ice crystals. These algae are also photosynthetic but are not bright green or red, but rather grey, brown or purple. They produce a purple pigment that acts as a UV shield that protects their delicate intracellular machinery from excessive light energy. The side effect of this is that the algae become very dark and have an albedo-lowering effect on the ice surface (see our Image of the Week). Ice with algae has a lower albedo than clean ice (Fig 2a) but, up to now, the magnitude of the biological darkening effect has not been quantified because of difficulties isolating algal darkening from that of mineral dusts, soot and the changing optical properties of the ice itself. This also limits our capability to map these algae using remote sensing. Samples of dark coloured ice examined under the microscope clearly show the presence of an algal community darkening the ice (Fig 2b).

In addition to surface-dwelling ice algae, microbial life exists in small pits known as cryoconite holes (see also this previous post). At the bottom of these holes exists a thin layer of granules comprising living microbial cells, dead cells, biogenic molecules, mineral fragments and soot. The organic matter in these granules is very dark, so they warm up when illuminated by the sun and melt into the ice. The relationship between cryoconite and ice surface albedo is complex because, although the cryoconite is dark, the hole geometry hides the granules beneath the ice surface.

Implications for the future of glaciers and ice sheets

The challenge facing scientists now is to quantify the bioalbedo effect by determining the optical properties of individual algal cells and remotely assessing their spatial coverage at the scale of entire glaciers and ice sheets. This will require new methods to be developed for detecting living cells from the air or space. Then, we must understand the factors controlling their growth, so we can predict biological darkening of ice in future climate scenarios. It is possible that algal coverage will increase as glaciers and ice sheets waste away because algae bloom where there is liquid melt water. Because of the darkening effect, an increasingly widespread algal ecosystem in a warming climate will accelerate the demise of its own habitat by enhancing glacier and ice sheet retreat.

Further reading

Edited by Scott Watson and Clara Burgard


Joseph Cook is a Postdoctoral Research Associate on NERC’s Black and Bloom project based at the University of Sheffield, UK where his remit is the measurement and modelling of surface albedo on the Greenland Ice Sheet. His background is in biotic-abiotic interactions on ice. He tweets as @tothepoles and blogs at http://tothepoles.wordpress.com. Contact Email: joe.cook@sheffield.ac.uk

Image of the week – Getting glaciers noticed!

Image of the week – Getting glaciers noticed!

Public engagement and outreach in science is a big deal right now. In cryospheric science the need to inform the public about our research is vital to enable more people to understand how climate change is affecting water resources and sea level rise globally. There is also no better way to enthuse people about science than to involve them in it. However, bringing the cryosphere to the public is a little more difficult when compared to other fields of science. Whilst volcanologists can cause mini explosions, seismologists can simulate earthquakes (such as Explosive Earth at last year’s Royal Society science fair) and realistic rivers can be simulated using interactive stream tables, combining ice and glacier dynamics in a public engagement setting can a little more challenging!


Despite the challenges involved in bringing the cryosphere to the public, a huge variety of great outreach projects concerned with glaciers exist, which deal with different aspects of the cryosphere; from using glacier goo to display how glaciers flow, recreating hydrology of a glacier with ice blocks, dressing up school children in fieldwork kit, or passing wires through ice to show regelation at work. But what should you keep in mind when planning your next cryospheric themed outreach activity?

Figure 2: The Vanishing Glacier of Everest stand at the Manchester Science festival [Credit: Owen King].

Keep it simple. By nature, academics are good at complexity. However, the most effective project I have been involved in was very simple – one where an ice block simply sat and melted (see our Image of the week). The team involved with this project came up with a vast array of complex ideas when planning the stand, but settled on the simple, effective idea of an ice block – which has been a great hit. The stand has now been to numerous science festivals, and people are constantly surprised by the ice being real! Once past the initial shock we have a great base from which to start conversations on the basics of how ice melts to the impact of climate change on glaciers around the world.

Keep it broad. Academics are also very good at forgetting just how specific their area of research is. You may want to link your outreach work to a particular project, but if you try to attempt something very specific you will spend a great deal of time talking to public about the basics before you get to the detail. To ensure everyone can get something out of your outreach work the best way is to provide a platform on which the basics can be taught but, if a conversation takes you there, you have the resources to explain your research in greater detail. At ‘Vanishing Glaciers of Everest’ we have the ice block for introductory discussions, but if someone gets really interested in the details we have figures and photos on the stand behind that can be used to introduce more complex areas of our research (Fig. 1 and Fig. 2).

Figure 2: Glacier goo at science and engineering week, Aberystwyth University [Credit: Morgan Gibson]

Make it interactive. Generally, people don’t want to be talked at. Instead, most people want to discuss what they know with you, so make it easy for them to do so. Give people something to do (e.g. glacier goo – Fig. 3) as soon as they reach the stand that they can explore on their own. You can then join them and ask exploratory questions, which starts a discussion rather than presenting to them. You are then likely to engage the person you are talking to much more effectively, and may well find out something yourself!

Consider all ages. Outreach work is often focused on children. However, adults are also a key demographic on which to focus. Engaging teachers and parents is vital to really bring home the importance of science to children in school and at home; I have found that almost all children have an interest in what you are saying, but without enthusiasm and interest from the supervising adult your hard work at engaging the children will not be encouraged once they leave. Consider how you will show how your aspect of science is fun, but also relevant to peoples’ everyday lives – that way you can appeal to both demographics.

Be innovative. Hanging an ice block from a wire to show regelation is cool, as is glacier goo. However, increasingly I am finding people have seen these experiments before, and are finding it all a little boring as a result. By repeating the same experiments again and again we are in danger of suggesting our research is static, which is obviously not the case! So be inventive when you are coming up with ideas and don’t forget all the new technology you could include!

Figure 4: “Icy bear” – a Twitter-based public engagement ‘project’ that documents research on microbes on ice, and fieldwork, across the world [Credit: Arwyn Edwards]

Be prepared for anything. I’ve had people talk to me, at length, about how the best way for us adapt to sea level rise is for all of us live in high rise blocks on hill tops. I’ve also spent a great deal of time explaining how we know anthropogenic climate change is real. You will get some strange questions and bold statements, but they are part of the experience. Keep an open mind and be positive; you meet amazing, interesting people at these events, and I have had conversations that have led to new research ideas, or to me rewriting paragraphs of a paper due to discussions at such events.

Be reflective. Spend some time considering the effectiveness of your outreach once you have finished (and recovered) from an event. What worked well and what didn’t? Do aspects of your stand or event need adapting for different audiences? Can you expand what you are doing to enable more flexibility on the overall message for your work? Being reflective will only lead to more effective public engagement, more interesting discussions, and you feeling satisfied that you have enthused and engaged public on your research, so it is worth doing!

 

 

Public engagement, done right, is incredibly rewarding. You not only spread your enthusiasm for research and get to discuss your work with a huge range of people, but it also enables you to show people that like science is relevant to everyone.

If you want to see some public outreach in action for yourself, the upcoming International APECS Polar Week (September 18-24, 2017) is a great chance to get involved in some outreach activities. For example, the #PolarWorld Frostbytes competition, to design a short audio or video recording used as a tool to help researchers easily share their latest findings with a broad audience!

Edited by Emma Smith


Morgan Gibson is a PhD student at Aberystwyth University, UK, and is researching the role of supraglacial debris in ablation of Himalaya-Karakoram debris-covered glaciers. Morgan’s work focuses on: the extent to which supraglacial debris properties vary spatially; how glacier dynamics control supraglacial debris distribution; and the importance of spatial and temporal variations in debris properties on ablation of Himalaya-Karakoram debris-covered glaciers. Morgan tweets at @morgan_gibson, contact email address: mog2@aber.ac.uk.

Image of the Week – See sea ice from 1901!

Image of the Week – See sea ice from 1901!

The EGU Cryosphere blog has reported on several studies of Antarctic sea ice (for example, here and here) made from high-tech satellites, but these records only extend back to the 1970s, when the satellite records began. Is it possible to work out what sea ice conditions were like before this time? The short answer is YES…or this would be a very boring blog post! Read on to find out how heroic explorers of the past are helping to inform the future.


During the Heroic Age of Antarctic Exploration (1897–1917), expeditions to the “South” by explorers such as Scott and Shackleton involved a great deal of time aboard ship. Our image of the week shows one such ship – the ship of the German Erich von Drygalsk – captured from a hot air balloon in 1901.

These ships spent many months navigating paths through sea ice and keeping detailed logs of their observations along the way. Climate scientists at the University of Reading, UK have used these logs to reconstruct sea-ice extent in Antarctica at this time – providing key information to extend satellite observations of sea ice around the continent.

Why do we want to know about sea-ice extent 100 years ago?

In the last three decades, satellite records of Antarctic sea-ice extent have shown an increase, in contrast to a rapid decrease in Arctic sea-ice extent over the same period (see our previous post). It is not clear if this, somewhat confusing, trend is unusual or has been seen before and without a longer record, it is not possible to say. This limits how well the sensitivity of sea ice to climate change can be understood and how well climate models that predict future ice extent can be validated.

To help understand this increase in Antarctic sea-ice extent; records of ice composition and nature from ships log books recorded between 1897–1917 have been collated and compared to present-day ice conditions (1989–2014).

What does the study show?

The comparison between sea ice extent in the Heroic Age and today shows that the area of sea ice around Antarctica has only changed in size by a very small amount in the last ~100 years. Except in the Weddell sea, where ice extent was 1.71o (~80 km) further North in the Heroic Age, conditions comparable to present-day were seen around most of Antarctica. This suggests that Antarctic sea-ice extent is much less sensitive to the effects of climate change than that Arctic sea ice. One of the authors of the study, Jonny Day, summarises these findings in the video below:

References and Further Reading

Planet Press

planet_pressThis is modified version of a “planet press” article written by Bárbara Ferreira and originally published on 26th November 2016 on the EGU website .

It is also available in Dutch, Hungarian, Serbian, French, Spanish, Italian and Portuguese! All translated by volunteers – why not consider volunteering to translate an article and learn something interesting along the way?

 

Edited by Sophie Berger

Image of the Week – Fifty shades of snow

Image of the Week – Fifty shades of snow

When I think of snow, I tend to either think about the bright white ski slopes in the mountains or the large white areas in the Arctic. However, natural phenomena can lead to colorful snow. Our Image of the Week shows snow can be green! Snow can also turn orange, pinkish, grey and even yellow… But where do these different shades of snow come from?


White

The most common color of snow is white (see Fig. 2). Snow generally appears white when it is pure snow, which means that it is only an aggregate of ice and snow crystals. When sunlight meets the snow surface, all frequencies of the sunlight are reflected several times in different directions by the crystals, leading to a white color of the snowpack.

 

Fig. 2: Fresh powder snow, snow crystals [Credit: Introvert, Wikimedia Commons]

 

 

If other particles or organisms are present in the snow though, they can alter the color of the snow’s surface…

Green

Snow can obtain a green color if it is host to an algal bloom (see our Image of the Week). Depending on the wetness of the snow, sunlight conditions and nutrient availability, unicellular snow algae can develop and thrive on the snow. Although it is not clear exactly how fast snow algae grow, algae populations from temperate regions have been found to grow sixteen-fold in one day! As the algae population increases, the snow turns green as the algae reflect the green light back.

 

Red/Pink

The pink-red-colored snow, commonly called “watermelon snow”, can also be caused by snow algae (see Fig. 3). The snow algae responsible for the pink color are similar to the ones responsible for green color. However, these algae use pigments of red color to protect their cells from high sunlight and UV radiation damage during the summer. Just like how we use sunscreen to protect our skin! The red pigments come either from iron tannin compounds or, more commonly, from orange to red-pigmented lipids.

There is also another origin for pink snow: Penguin poo! Indeed, the krill they eat contain a lot of carotenoids that give their poo a red color.

Fig. 3: Watermelon snow streaks [Credit: Wikimedia Commons].

 

Yellow

Yellow snow is the result of a different process (and no, it is not from Penguin pee!). Fig. 4 shows the Sierra Nevada in Spain before and after dust transported from the Sahara settled down on the snow-covered mountain tops. The dust was lifted up from the Sahara desert and blown north before ending its trip in Spain.

Fig. 4: Snow-covered Sierra Nevadas (Spain) before and after a dust deposition event [Credit: modified from NASA’s Earth Observatory]

 

Do these colors have an influence on snow cover?

In all cases of colored snow, the snow surface is darker than before. The darker surface absorbs more sunlight than a white surface, which causes the snow to melt faster… Therefore, although it looks artistic, colored snow is not necessarily healthy for the snow itself…

 

So, if you don’t like winter because everything is boring and white, just think about the variety of snow colors and try to look out for these special types! 🙂

 

Further reading

Edited by David Rounce

Image of the Week – Summer is fieldwork season at EastGRIP!

Image of the Week – Summer is fieldwork season at EastGRIP!

As the days get very long, summer is a popular season for conducting fieldwork at high latitudes. At the North East Greenland Ice Stream (NEGIS), the East Greenland Ice-core Project (EastGRIP) is ongoing. Several scientists are busy drilling an ice core through the ice sheet to the very bottom, in continuation to previous years (see here and here). This year, amongst others, several members from the European Research Council (ERC) supported synergy project ice2ice are taking part in the work at EastGRIP. Besides sleeping in the barracks that can be seen in our Image of the Week, the scientists enjoy the international and interdisciplinary setting and, of course, the work in a deep ice core drilling camp…


Life at the EastGRIP camp

In total, 22 people live in the camp (see Fig.2): 1 field leader, 5 ice core drillers, 4 ice core loggers, 3 people working with the physical properties of the ice, 2 are doing continuous water isotope analysis, 2 surface science scientists, 2 field assistants, and 1 mechanic, 1 electrical engineer and most important an excellent cook. We cover a variety of nationalities: British, Czech, Danish, French, German, Japanese, Korean, Norwegian, Russian and more. The crew changes every four weeks and the EastGRIP project aims to get as many young scientists (Master and PhD students) into camp as possible, so that it also works as a learning environment for new generations. In total, the number of people that have and will spent time at EastGRIP this season is almost 100, making it a buzzing science hub. This environment leads to extensive science discussions over the dinner table and therefore facilitates the interdisciplinary connections so vital in ice core science.

Fig.2: The current crew at EastGRIP dressed up for the Saturday party (tie and dress obligatory!) [Credit: EastGRIP diaries].

Science at the EastGRIP camp

The main aim of the EastGRIP project is to retrieve an ice core by drilling through the North East Greenland Ice Stream (NEGIS) up to a depth of 2550 m (!). Ice streams are responsible for draining a significant fraction of the ice from the Greenland Ice Sheet (see Fig. 3). We hope to gain new and fundamental information on ice stream dynamics from the project, thereby improving the understanding of how ice streams will contribute to future sea-level change. The EastGRIP project has many international partners and is managed by the Centre for Ice and Climate, Denmark with air support carried out by US ski-equipped Hercules aircraft managed through the US Office of Polar Programs, National Science Foundation.

Fig. 3: Ice velocities from RADARSAT synthetic aperture radar data are shown in color and illustrate the wedge of fast-flowing ice that begins right at the central ice divide and cuts through the ice sheet to feed into the ocean through three large ice streams (Nioghalvfjerds isstrømmen, Zachariae isbræ, and Storstrømmen). [Credit: EastGRIP, data from Joughin et al., 2010]

Currently, four Norwegian and Danish scientists from the ice2ice project have joined the EastGRIP project to conduct field work at the ice core drilling site. The ice2ice project focuses on how land ice and sea ice influence each other in past, present, and future. Thus, being at the EastGRIP site is a great opport

unity for us in ice2ice to learn more about how the fast-flowing ice stream in North East Greenland may influence the stability of the Greenland ice cap and to enjoy the collaborative spirit at an ice core drilling site.

 

This year’s fieldwork at EastGRIP started in May and will continue until August. We aim to make it through the brittle zone of the ice. This is a zone where the gas bubbles get enclosed in the ice crystals and thus the ice is, as the name indicates, more brittle than at other depths. Unfortunately for us, the brittle zone makes it very hard to retrieve the ice in a great quality. This is because of the pressure difference between the original depth of the ice and the surface, that causes the ice to fracture when it arrives at the surface. We are doing our very best to stabilize the core and several optimizations in terms of both drilling and processing of the ice core are being applied.

Fig. 4: Cross-section view of an ice core [Credit: Helle Astrid Kjær].

Still, a large part of the core can already be investigated (see Fig. 4) for water isotopes to get information about past climate. Also, ice crystals directions are being investigated through thin slices of the ice core to help better understanding the flow of the NEGIS. On top of the deep ice core, which is to be drilled to bedrock over the coming years, we are doing an extensive surface program to look at accumulation changes.

In the large white plains…

Despite all the fun science and people, when you are at EastGRIP for more than 4 weeks, you have a very similar landscape everyday and can miss seeing something else than just the great white. About a week ago, a falcon came by to remind us of the rest of the world (see Fig. 5). It flew off after a couple of days. We will follow its path to the greener parts of Greenland when we will soon fly down to Kangerlussuaq. Someone else will then take over our job at EastGRIP and enjoy the wonders of white…

Fig.5: Visit of a falcon [Credit: Helle Astrid Kjær].

Further reading

Edited by Clara Burgard


Helle Astrid Kjær is a postdoc at the Centre for Ice and Climate at the Niels Bohr Institute at University of Copenhagen. When she is not busy in the field drilling and logging ice cores, she spends most of her time in the lab retrieving the climate signal from ice cores. These include volcanic events, sea salts, dust with more by means of Continuous Flow Analaysis (CFA). Further she is hired to manage the ice2ice project.

Image of the Week — High altitudes slow down Antarctica’s warming

Elevations in Antarctica. The average altitude is about 2,500m. [Credit: subset of Fig 5 from Helm et al (2014)]

When it comes to climate change, the Arctic and the Antarctic are poles apart. At the north of the planet, temperatures are increasing twice as fast as in the rest of the globe, while warming in Antarctica has been milder. A recent study published in Earth System Dynamics shows that the high elevation of Antarctica might help explain why the two poles are warming at different speeds.


The Arctic vs the Antarctic

At and around the North Pole, in the Arctic, the ice is mostly frozen ocean water, also known as sea ice, which is only a few meters thick. In the Antarctic, however, the situation is very different: the ice forms not just over sea, but over a continental land mass with rugged terrain and high mountains. The average height in Antarctica is about 2,500 metres, with some mountains rising as high as 4,900 metres.

A flat Antarctica would warm faster

Mount Jackson in the Antarctic Peninsula reaches an altitude of 3,184 m  [Credit: euphro via Flickr]

Marc Salzmann, a scientist working at the University of Leipzig in Germany, decided to use a computer model to find out what would happen if the elevation in Antarctica was more like in the Arctic. He discovered that, if Antarctica were flat, there would be more warm air flowing from the equator to the poles, which would make the Antarctic warm faster.

As Antarctica warms and ice melts, it is actually getting flatter as time goes by, even if very slowly. As such, over the next few centuries or thousands of years, we could expect warming in the region to speed up.

Reference/further reading

planet_pressThis is modified version of a “planet press” article written by Bárbara Ferreira and originally published on 18 May 2017 on the EGU website
(a Serbian version is also available, why not considering adding a new language to the list? 🙂 )

Image of the Week – A rather splendid round-up of CryoEGU!

Image of the Week – A rather splendid round-up of CryoEGU!

The 2017 edition of the EGU general assembly was a great success overall and for the cryospheric division in particular. We were for instance thrilled to see that two of the three winning photos of the EGU Photo contest featured ice! To mark the occasion we are delighted to use as our image of this week,  one of these pictures, which  shows an impressive rapid in the Pite River in northern Sweden. Congratulations to Michael Grund for capturing this stunning shot.  You can find all photos entered in the contest on imaggeo — the EGU’s  open access geosciences image repository.

But being the most photogenic division (at least the ice itself is…not sure about the division team itself!) was not our only cryo-achievement during the conference. Read on to get the most of (cryo)EGU 2017!


EGU 2017 in figures

  • 17,399 abstracts in the programme (including 1179 to cryo-related sessions)
  • 14,496 scientists from 107 countries attending the conference
  • 11,312 poster, 4,849 oral and 1,238 PICO presentations
  • 649 scientific sessions and 88 short courses
  • 53% of early-career scientists

Polar Science Career Panel

During the week we teamed up with APECS to put on a Polar Science Career Panel. Our five panellists, from different backgrounds and job fields, engaged in a lively discussion with over 50 session attendees. With many key topics being frankly and honesty discussed by our panelists, who had some great comments and advice to offer. Highlights of the discussion can be found on the @EGU_CR twitter feed with #CareerPanel.

At the end we asked each panellist to come up with some final words of advice for early-career scientists, which were:

  • There is no right and wrong, ask other people and see what you like
  • Remember you can shape your own job
  • Take chances! Even if you are likely to fail and think outside the box
  • Remember that you are a whole human being… not only a scientist and use all your skills
  • And last but not least… come and work at Carbon Brief (thanks Robert McSweeney!!)

However, the most memorable quotation of the entire panel is arguably from Kerim Nisancioglu :

Social media

One of the things the EGU Cryosphere team has been recognised for is its great social media presence. We tweeted away pre-EGU with plenty of advice, tips and information about events during the week and also made sure to keep our followers up-to-date during the week.
If it is not yet the case, please consider following us on twitter and/or facebook to keep updated with the latest news about the cryosphere division, the EGU or any other interesting cryo-related news!

We need YOU for the EGU cryosphere division

Conferences are usually a great way to meet new people but did you know that getting involved with the outreach activities of the division is another way?

Each division has an ECS (early-career scientist) representative and a team to go with that and the Cryosphere division is one of the most active. Our new team of early-career scientists for 2017/18 includes some well known faces and some who are new to the division this year:

Nanna Karlsson : outgoing ECS representative and incoming coordinator for posters and PICOs awards

Emma Smith : incoming ECS representative and outgoing co-chief editor of the  cryoblog

Sophie Berger: chief-editor of the cryoblog and incoming outreach officer

Clara Burgard : incoming co-chief editor the cryoblog

 

 

 

We also have many more people (who aren’t named above) involved in the blog and social media team AND the good news is that we are looking for new people to either run our social media accounts and/or contribute regularly to this “award winning” cryoblog. Please get in touch with Emma Smith (ECS Representative and former blog editor) or Sophie Berger (Chief Blog Editor and Outreach Officer) if you would like to get involved in any aspect of the EGU Cryosphere team. No experience is necessary just enthusiasm and a love of bad puns!

And here is your “Save the Date” for EGU 2018 – which will be held between 8th – 13th April 2018.

Co-authored by Emma Smith and Sophie Berger

Quantarctica: Mapping Antarctica has never been so easy!

Quantarctica: Mapping Antarctica has never been so easy!

One of the most time-consuming and stressful parts of any Antarctic research project is simply making a map. Whether it’s plotting your own data points, lines, or images; making the perfect “Figure 1” for your next paper, or replying to a collaborator who says “Just show me a map!,” it seems that quick and effective map-making is a skill that we take for granted. However, finding good map data and tools for Earth’s most sparsely-populated and poorly-mapped continent can be exhausting. The Quantarctica project aims to provide a package of pre-prepared scientific and geographic datasets, combined with easy-to-use mapping software for the entire Antarctic community. This post will introduce you to Quantarctica, but please note that the project is organizing a Quantarctica User Workshop at the 2017 EGU General Assembly (see below for more details).


[Credit: Quantarctica Project]

What is Quantarctica?

Quantarctica is a collection of Antarctic geographic datasets which works with the free, open-source mapping software QGIS. Thanks to this Geographic Information System package, it’s now easier than ever for anyone to create their own Antarctic maps – for any topic and at any spatial scale. Users can add and plot their own scientific data, browse satellite imagery, make professional-quality maps and figures, and much, much more. Read on to learn how researchers are using Quantarctica, and find out how to use it to start making your own (Qu-)Antarctic maps!

Project Origins

When you make a sandwich, you start with bread, not flour. So why would you start with ‘flour’ to do your science?” — Kenny Matsuoka, Norwegian Polar Institute

Deception Island isn’t so deceptive anymore, thanks to Quantarctica’s included basemap layers, customized layer styles, and easy-to-use cartography tools. [Credit: Quantarctica Project]

Necessity is the mother of invention, and people who work in Antarctica are nothing if not inventive. When Kenny Matsuoka found himself spending too much time and effort just locating other Antarctic datasets and struggling with an expired license key for his commercial Geographic Information System (GIS) software in the field, he decided that there had to be a better way – and that many of his Antarctic colleagues were probably facing the same problems. In 2010, he approached Anders Skoglund, a topographer at the Norwegian Polar Institute, and they decided to collaborate and combine some of the critical scientific and basemap data for Antarctica with the open-source, cross-platform (Windows, Mac, and Linux) mapping software QGIS. Quantarctica was born, and was quickly made public for the entire Antarctic community.

Since then, maps and figures made with Quantarctica have appeared in at least 25 peer-reviewed journal articles (that we can find!). We’ve identified hundreds of Quantarctica users, spread among every country participating in Antarctic research, with especially high usage in countries with smaller Antarctic programs. We’ve been actively incorporating even more datasets into the project, teaching user workshops at popular Antarctic conferences – such as EGU 2017 – and building educational materials on Antarctic mapping for anyone to use.

A great example of a Quantarctica-made figure published in a paper. Elevation, imagery , ice flow speeds, latitude/longitude graticules, custom text and drawing annotations… it’s all there and ready for you to use! [Credit: Figs 1 and 2 from Winter et al (2015)].

What data can I find in Quantarctica?

  • Continent-wide satellite imagery (Landsat, MODIS, RADARSAT)
  • Digital elevation models and/or contour lines of bed and ice-surface topography and seafloor bathymetry
  • Locations of all Antarctic research stations and every named location in Antarctica (the SCAR Composite Gazetteer of Antarctica)
  • Antarctic and sub-Antarctic coastlines and outlines for exposed rock, ice shelf, and subglacial lakes
  • Magnetic and gravity anomalies
  • Ice flow velocities, catchment areas, mass balance, and firn thickness grids
  • Ancient UFO crash sites

…just to name a few!

Four examples of included datasets. From left to right: Ice flow speed, drainage basins, and subglacial lakes; bed topography; geoid height; modeled snow accumulation and surface blue ice areas [Credit: Quantarctica Project]

All of these datasets have been converted, imported, projected to a standard Antarctic coordinate system, and hand-styled for maximum visibility and compatibility with other layers. All you have to do is select which layers you want to show! The entire data package is presented in a single QGIS project file that you can quickly open, modify, save, and redistribute as your own. We also include QGIS installers for Windows and Mac, so everything you need to get started is all in one place. And finally, all of the data and software operates entirely offline, with no need to connect to a license server, so whether you’re in a tent in Antarctica or in a coffee shop with bad wi-fi, you can still work on your maps!

Quantarctica was used in traverse planning for the MADICE Project, a collaboration between India’s National Centre for Antarctic and Ocean Research (NCAOR) and the Norwegian Polar Institute (NPI), investigating mass balance, ice dynamics, and climate in central Dronning Maud Land. Check out pictures from their recently-completed field campaign on Facebook and Twitter! Base image: RADARSAT Mosaic; Ice Rises: Moholdt and Matsuoka (2015); Mapping satellite features on ice: Ian Lee, University of Washington; Traverse track: NCAOR/NPI. [Credit: Quantarctica Project]

Every dataset in Quantarctica is free for non-commercial use, modification, and redistribution – we get explicit permission from the data authors before their datasets are included in Quantarctica, always include any README or extra license/disclaimer files, and never include a dataset if it has any stricter terms than that. We always provide all metadata and citation information, and require that any Quantarctica-made maps or figures printed online or in any publication include citations for the original datasets.

How do I start using Quantarctica?

Quantarctica is available for download at http://quantarctica.npolar.no/. It’s a 6 GB package, so if your internet connection is struggling with the download, just contact us and we can send it to you on physical media. You can use the bundled QGIS installers for your operating system, or download the latest version of QGIS at http://qgis.org/ and simply open the Quantarctica project file, Quantarctica.qgs, after installation.

We’re actively developing Version 3 of Quantarctica, for release in Late 2017. Do you know of a pan-Antarctic dataset that you think should be included in the new version? Just email the Quantarctica project team at quantarctica@npolar.no.

Quantarctica makes it easy to start using QGIS, but if you’ve never used mapping software before or need to brush up on a few topics, we recommend QGIS Tutorials and Tips and the official QGIS Training Manual. There are also a lot of great YouTube tutorial videos out there!

 

Nobody said you could only use Quantarctica for work – you can use it to make cool desktop backgrounds, too! Foggy day in the Ross Island / McMurdo Dry Valleys area? Though it often is, the fog effects image was created using only the LIMA 15m Landsat Imagery Mosaic and RAMP2 DEM in Quantarctica, with the help of this tutorial. [Credit: Quantarctica Project]

Quantarctica Short Course at EGU 2017

Are you attending EGU 2017 and want to learn how to analyze your Antarctic data and create maps using Quantarctica? The Quantarctica team will be teaching a short course (SC32/CR6.15) on Monday, 24 April at 13:30-15:00 in room -2.31. Some basic GIS/QGIS experience is encouraged, but not required. If you’re interested, fill out the registration survey here: https://goo.gl/forms/mLaJg686tZq8bm2N2 and feel free to send any questions or comments to quantarctica@npolar.no. We’ll see you in Vienna!

Edited by Kenny Matsuoka and Sophie Berger

Reference/Further Reading

Data sources

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