GeoLog

This week’s Imaggeo on Mondays is brought to you by the photographer himself, Fabien Darrouzet who captured the beautiful glacial landscape during a summer expedition to the Arctic. 

“Arctic through a porthole” by Fabien Darrouzet, distributed by the EGU under a Creative Commons Licence.

This picture was taken in Svalbard (78° lat.) in June 2012. I was there for one week in order to observe the transit of the planet Venus in front of the Sun. I came here because at this time of the year, the Sun is shining all day (midnight Sun), so it was possible to see Venus during most of the transit (for over six and a half hours!), and not only during its last minutes, as was the case for most parts of Europe.

During the days before the transit, I made a boat trip inside the fjords around Longyearbyen, and in particular in the Isfjorden, where I took this picture through the porthole of the boat. This is the southern border of a territory of Svalbard named Oscar II Land. This area, and indeed all of Svalbard, is covered by snow most of the time, and just a few plants can germinate during July-August, when the average temperature is 5°C.

Svalbard is a very important island and region because it is dominated  by glaciers (60% of all the surface), which are important indicators of global warming and can reveal possible answers as to what the climate was like up to several hundred thousand years ago. Those glaciers are studied and analysed by scientists in order to better observe and understand the consequences of the global warming on our Earth.

By Fabien Darrouzet, Belgian Institute for Space Aeronomy

Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their images to this repository and since it is open access, these photos can be used by scientists for their presentations or publications as well as by the press and public for educational purposes and otherwise. If you submit your images to Imaggeo, you retain full rights of use, since they are licensed and distributed by EGU under a Creative Commons licence.

The Lena River flows throughout Russia from its source in the Baikal Mountains out into the Arctic Ocean, where the delta’s landscape is dominated by ice-rich Yedoma and thermokarst lakes. Thermokarst lakes have been identified as a source of carbon release to the atmosphere and Yedoma-like lake sediments are known to release more methane than any other sediment due to their incredibly high carbon content. So what is a thermokarst lake?

The Lena River Delta, dominated by Yedoma uplands and thermokarst lakes. Image taken by LANDSAT (source: NASA).

Thermokarst is a landscape that results from the thawing of both icy permafrost and larger ice masses. In northern Siberia, thermokarst starts to develop at the surface: once the ground subsidises, water accumulates in a series of small basins known as alasses. They continue to grow in size to form thermokarst lakes, which can either drain or coalesce with neighbouring lakes to form even larger ones that can reach several kilometres in diameter. When thermokarst lakes drain, they leave behind much smaller lake remnants that lie with a flat basin with steeply sloping sides. Multiple cycles of thermokarst development can occur within a single thermokarst basin to create a complex thermokarst landscape peppered with lakes and islands.

Kurungnakh Island, which lies within the Lena River Delta, formed during the Pleistocene and is part of the region’s thermokarst landscape. The cliff below exposes the Yedoma, a series of silty permafrost deposits with high ice and carbon contents. Permafrost is soil that is either at or below the freezing point of water and forms in regions where the mean annual temperature is below this. Permafrost soils are very rich in carbon, which is stored as peat and methane. The release of this carbon into the atmosphere has the potential to accelerate climate warming through a positive feedback system. That is, where a small change (the release of methane due to permafrost melt) has the capacity to cause a change of even greater magnitude (the presence of more methane in the atmosphere increases the temperature and accelerates the rate of permafrost degradation, releasing even more methane…).

The most immediately recognisable form of permafrost degradation is the presence of thermokarst – you can get a feel for this in the photo below:

“Kurungnakh Island” by Sebastian Zubrzycki. Distributed by the EGU under a Creative Commons licence.

The pale lower unit is comprised of fluvial sand, overlain by ice-rich permafrost (light grey) and capped with a thin covering of Holocene peat. Fluvial sands in this region are relatively ice-poor, which limits the capacity for further thermokarst development. While there is relatively little capacity for further thermokarst development, it is important to consider other processes associated with permafrost degradation and the rates at which they occur. In doing so, we can better quantify future carbon fluxes from permafrost soils in as the climate warms.

Reference:

Morgenstern, A., Grosse, G., Günther, F., Fedorova, I., and Schirrmeister, L.: Spatial analyses of thermokarst lakes and basins in Yedoma landscapes of the Lena Delta, The Cryosphere, 5, 849-867, doi:10.5194/tc-5-849-2011

Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their images to this repository and since it is open access, these photos can be used by scientists for their presentations or publications as well as by the press and public for educational purposes and otherwise. If you submit your images to Imaggeo, you retain full rights of use, since they are licenced and distributed by EGU under a Creative Commons licence.

These are the outwash plains for the Icelandic volcano, Katla:

“Sandstorm, Myrdalssandur outwash plain, Iceland” by Ragnar Th Sigurdsson. This image is distributed by the European Geosciences Union under a Creative Commons licence.

An outwash plain (or sandur) is a broad, shallowly sloping region ahead of a glacial front. They are made up of material that has been deposited by glacial meltwater, released either by geothermal heating or a subglacial eruption. The extensive volcanism and abundance of ice-capped volcanoes in southern Iceland means that the outwash plains are particularly well developed here.

The Mýrdalssandur outwash plain in relation to the volcano Katla (Mýrdasljökull) [source: Jóhannesdóttir and Gísladóttir, 2010].

Between flooding events, some vegetation takes hold, but much of the soil is loose and easily transported by wind. Indeed, the soil islands you see in the photo are formed by wind-blown soil and if they were to erode, the area would be a desert consisting of glacial alluvial sediments alone. Sandstorms, such as the one above, carry fine particulate matter (clays and glacial till) from the outwash plains to other areas and even contribute to the particulate pollution in Reykjavík, some 110 km away!

References:

Jóhannesdóttir, G. and Gísladóttir, G.: People living under threat of volcanic hazard in southern Iceland: vulnerability and risk perception, Natural Hazards Earth System Science, 10, 407-420, doi:10.5194/nhess-10-407-2010, 2010.

Thorsteinsson, T., Gísladóttir, G., Bullard, J. and McTainsh, G.: Dust storm contributions to airbourne particulate matter in Reykjavík, Iceland, Atmospheric Environment, 45, 5924-5933.

Warner, N.H.: Catastrophic outwash plains on Earth and Mars: comparisons from Iceland and Chasma Boreale, Mars. PhD thesis, Arisona State University, December, 2008.

You can find more Arctic images from Ragnar Th Sigurdsson here, and more from the Imaggeo open access database here.

Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their images to this repository and since it is open access, these photos can be used by scientists for their presentations or publications as well as by the press and public for educational purposes and otherwise. If you submit your images to Imaggeo, you retain full rights of use, since they are licenced and distributed by EGU under a Creative Commons licence.

This week’s Imaggeo on Mondays is brought to you by the photographer herself, Marion Bisiaux (now at Stendhal University, Grenoble, France), who tells us about her exciting field trip to the British Columbia’s Coast Range.

“Combatant Col under a storm” by Marion Bisiaux, distributed by the European Geosciences Union under a Creative Commons licence.

This picture was taken during the Waddington Range Ice Core Project in which I participated during my PhD at the University of Nevada, Reno, US and at the Desert Research Institute, also in Reno. The scene was captured in July 2010, during a month-long field trip at the Combatant Col, the mountain pass below Mount Waddington in British Columbia’s Coast Range that sits at 3000m elevation and contains more than 200m of ice. The aim of the project was to drill an ice core to retrieve information on the past climate of the area. The results were published in 2012 in the Journal of Glaciology and are available online.

The camp (tents only) was located just below the massive north face of Mount Waddington. The weather was rather rough as we had several storms hitting the camp, but the scenery was impressive, with avalanches running on Mount Waddington’s face, crevasses, overhanging seracs, among other phenomena. The photograph shows the high winds on the Mount that stopped the ice-core drilling for a few days and forced drillers to hide in their tents.

Notwithstanding the strong weather and striking scenery, what I remember the most is the human aspect of this scientific expedition. Everyone was very motivated, working very hard to make the drill happen, and united by the same goal: the success of the expedition and the increase of knowledge.

This field trip will be the topic of a book Carnet Glacé (in French), which will tell the story of the expedition.

By Marion Bisiaux, glaciologist and science communication student

Imaggeo is the online open access geosciences image repository of the European Geosciences Union. Every geoscientist who is an amateur photographer (but also other people) can submit their images to this repository. Being open access, it can be used by scientists for their presentations or publications as well as by the press. If you submit your images to imaggeo, you retain full rights of use, since they are licenced and distributed by EGU under a Creative Commons licence.

“Melting ice” by Thomas Ernsdorf, distributed by the European Geosciences Union under a Creative Commons licence.

The speed and extent of Greenland’s ice sheet melt dominated the media over the summer, and for good reason. Dramatic satellite images showed that, in just a few days, 97% of the island’s ice sheet surface thawed, melting over a larger area than at any time in more than 30 years of satellite observations. Usually, during the summer only around half of the surface of Greenland’s ice sheet melts and much of it refreezes or is replaced.

The Steenstrup Gletscher (Glacier) is a wide glacier in northwestern Greenland, known for the number and size of the icebergs that are calved from its spectacular central portion. Steenstrup has retreated 10km over the past 60 years and around 20km over the past century, a worrying trend because of the potentially catastrophic consequences of rising sea levels on coastal areas worldwide.

Meteorologist Thomas Ernsdorf (University of Trier, Germany) describes his encounter with this massive wall of ice, when he captured this spectacular picture, “I took this shot during Greenland’s melting season. The picture shows melting ice in front of Steenstrup Glacier in June 2010. It was taken at a height of 30m above ground level using the Polar 5 aircraft. I was there as part of the IKAPOS campaign, which aims to investigate the North Water (NOW) polynya, a huge area of open water surrounded by sea-ice.  As a consequence of global warming, the ice mass of Greenland will be reduced enormously.”

The Polar 5 aircraft, a Basler BT-67 featuring specialised aeronautical and scientific instrumentation, is operated by the Alfred Wegener Institute for Polar and Marine Research and is widely used to measure the extent of the Arctic ice melt. It was inaugurated in October 2007. A photo gallery featuring this specially equipped plane can be found on the Alfred Wegener Institute website.

Imaggeo is the online open access geosciences image repository of the European Geosciences Union. Every geoscientist who is an amateur photographer (but also other people) can submit their images to this repository. Being open access, it can be used by scientists for their presentations or publications as well as by the press. If you submit your images to imaggeo, you retain full rights of use, since they are licenced and distributed by EGU under a Creative Commons licence.

“The Power of Ice” by Romain Schläppy, distributed by the European Geosciences Union under a Creative Commons licence.

There has been a lot of talk about Greenland lately in the context of global climate change. And for good reason. Over 80% of its total surface is covered by ice, the volume of which exceeds 2,850,000 km3 or enough to raise global sea levels by a staggering 7 m if fully melted.

The Greenland ice sheet consists of layers of compressed snow from over 100,000 years of snowfall. As a result, ice cores drilled into its summit provide, through their layering and chemical composition, an unparalleled record of climate change in the Northern Hemisphere. These historical data include evidence that the planet’s weather has often shifted from one seemingly stable state to another.

Despite its sheer enormity and frigid hostility, the Greenland ice sheet remains as beautiful as it is mysterious. This vivid picture was captured from a helicopter by Romain Schläppy during a field trip in September 2011. He explains, “This picture illustrates several small glaciers surrounding the Greenland ice cap, in Tassilaq, near Kulusuk, East Greenland. Dark lines represent moraines formed by the movement of rock material from the mountains tops towards the sea. An important current scientific area consists of placing the recent and ongoing Greenland warming in the broader context of past changes in south Greenland land climate, vegetation, sedimentation, and ice history.”

Greenland is an autonomous country within the Kingdom of Denmark and, by area, the world’s largest island. It has a population of 56,749 (2012 est.) and a total area of 2,166,086 km2, making it the least densely populated country in the world.

Imaggeo is the online open access geosciences image repository of the European Geosciences Union. Every geoscientist who is an amateur photographer (but also other people) can submit their images to this repository. Being open access, it can be used by scientists for their presentations or publications as well as by the press. If you submit your images to imaggeo, you retain full rights of use, since they are licenced and distributed by EGU under a Creative Commons licence.

Today’s text is brought to you by the author of this impressive picture, Patrick Klenk (Heidelberg University, Germany).

“Wonderland” by Patrick Klenk, distributed by EGU under a Creative Commons licence

This photograph is part of a series of images which I took in Death Valley National Park on a brisk December morning in 2011. In this case, we were close to Aguereberry Point, a mountain viewpoint located at 1961m above sea level, overlooking the central part of this “vast geologic museum”. This was our  first trip to the Death Valley, and the scenery was unlike anything I would have expected, which was mostly due to a 5cm snow cover that had fallen the previous night. When we got to the viewpoint early in the morning, the last clouds were just moving out and the strong winds had created these delicate icy structures on shrubs, rocks and grasses, which instantly started to sparkle and glow as soon as the sun came out. Especially when viewed against a backlighting sun, one got the impression of an almost unworldly setting, seemingly defying gravity. It didn’t last for long, however – the sun melted everything away within just a couple of hours. Hence, this image truly was about being in the right place at the right time, about capturing a glimpse of an ephemeral winter wonderland.

The picture was taken with a Nikon D7000, using a 18-105mm lens. Aperture was f/11, with exposure of 1/320s at ISO 160 and a focal length of 105mm. Beyond the black-white conversion (using Silver Efex Pro 2), no further picture editing was carried out except for  adding a little vignette for emphasizing the subtle backlighting atmosphere of the central part of the image.

In my real life, I am a physicist, currently working at the Institute of Environmental Physics, Heidelberg University, Germany, on novel approaches for using Ground-Penetrating Radar for Quantitative Soil Hydrology.

By Patrick Klenk

Imaggeo is the online open access geosciences image repository of the European Geosciences Union. Every geoscientist who is an amateur photographer (but also other people) can submit their images to this repository. Being open access, it can be used by scientists for their presentations or publications as well as by the press. If you submit your images to imaggeo, you retain full rights of use, since they are licenced and distributed by EGU under a Creative Commons licence.

The text of this week’s Imaggeo on Mondays comes from the photographer herself, Madlen Gebler, who tells us the tragic story behind this stunning picture.

“Glimpse of heaven” by Madlen Gebler, distributed by the European Geosciences Union under a Creative Commons license.

This picture was taken on the 2nd of March 2008 on board the research vessel Polarstern during the expedition ANT XXIV-3. After a four-week cruise we arrived in Atka Bay, Antarctica, in front of the German Antarctic research station Neumayer. I’ve never seen a sunrise like the one I saw that day and captured in this photograph; it was simply amazing. That morning the sunlight was reflected by the ice in a way which made it sparkle like diamonds with colours from yellow to red.

Shortly after taking this picture, I was standing together with a colleague, Willem Polman, at the bridge’s portside window. We were talking about how privileged we are because our work gives us the chance to visit Antarctica, the most fascinating continent on Earth, in my view. This picture is named “Glimpse of heaven” because it was the last glimpse of heaven before we went through hell. Just three hours after this picture was taken, Willem Polman died together with Stefan Winter in a helicopter accident.

Scientists are privileged people in that their work takes them to amazing places; but we should never forget that sometimes we pay a very high, too high, price for our work. I dedicate this to Willem and Stefan – we missed you sadly during the rest of the cruise.

By Madlen Gebler, Alfred Wegener Institute (Germany)

Imaggeo is the online open access geosciences image repository of the European Geosciences Union. Every geoscientist who is an amateur photographer (but also other people) can submit their images to this repository. Being open access, it can be used by scientists for their presentations or publications as well as by the press. If you submit your images to imaggeo, you retain full rights of use, since they are licenced and distributed by EGU under a Creative Commons licence.

The text of this week’s Imaggeo on Mondays comes from the photographer himself, Phillip Blaen (University of Birmingham), who took the picture while on fieldwork for his PhD studies. Phillip researches the impacts of climate change on the hydrology and ecology of Artic rivers.

“Arctic iceberg” by Phillip Blaen, distributed by the European Geosciences Union under a Creative Commons licence

Last year, I was working in a small research village called Ny Alesund, which is on the shore of Kongsfjord in north-west Spitsbergen (the largest island of the Svalbard archipelago). Some of my field sites were accessed by boat. I had spent all summer in Svalbard and this was my last boat trip to collect equipment from a site on the other side of the fjord. It was a wet and miserable day. I didn’t expect to get any good photos, but I put my camera in my bag just in case. Then I saw this iceberg floating in the water. The colour of it really contrasted with the darkness of the surrounding landscape – it was almost shining!

Icebergs calve from glaciers throughout the summer in Svalbard. On a warm day the sound of the falling ice hitting the water fills the air like thunder. But many glaciers in Svalbard are now shrinking and the rate of thinning has increased in recent years. This iceberg came from the Kongsbreen glacier at the head of Kongsfjord. The glacier has retreated by several hundred meters in the last half-century. A few decades ago, the location where this photo was taken would have been covered by ice.

By Phillip Blaen

Imaggeo is the online open access geosciences image repository of the European Geosciences Union. Every geoscientist who is an amateur photographer (but also other people) can submit their images to this repository. Being open access, it can be used by scientists for their presentations or publications as well as by the press. If you submit your images to imaggeo, you retain full rights of use, since they are licenced and distributed by EGU under a Creative Commons licence.

In this month’s Geosciences Column, Amanda Gläser-Bligh writes about SAR (synthetic aperture radar) satellites and how they can be used to map glacier lakes and mitigate related flood hazards.

Glaciers are a natural storage system and provide a perennial source of fresh water to the surrounding low-lying areas, which can be used for drinking water, irrigation, or even hydroelectricity. But when glaciers melt rapidly and form lakes before unstable moraines, the possibility of glacial lake outburst floods increases, causing concern for nearby population centers.

Due to the ever-changing nature of glacial lakes, Dr Tazio Strozzi and his team have developed a method to monitor these changes as they happen to limit the catastrophic potential from the lake outbursts. Their ideas are presented in the paper, “Glacial lake mapping with very high resolution satellite SAR data” recently published in the EGU open-access journal, Natural Hazards and Earth System Sciences.

Most glacial lakes are located in areas that are difficult to monitor terrestrially. An easier approach is to monitor changing surface conditions from space. To get the level of detail needed for developing lakes in remote regions, synthetic aperture radar (SAR) satellites are employed. These satellites can produce images at a 2-m interval – enough to determine the boundaries of a lake when a trained person examines the pictures. And SAR is not dependent on the weather, whereas other optical methods have trouble creating images through cloud cover or at night.

The orbit of a single SAR satellite moves in a coil-like motion, longitudinally around the planet and can take anywhere between 11 and 46 days to come back to a specific location, depending on the satellite. But since there are a good number of available operating SAR satellites, their efforts can be combined so that more frequent observation of an area can occur; image data on a single lake-forming region can therefore be gathered within hours. Such areas could be potentially dangerous, time-consuming, and expensive for a geological team to approach, showing the advantages of using satellite imagery.

There are some limitations, though. Smaller lakes are difficult to map with SAR. Computers are also not able to analyze the data alone, as backscattering and noise often makes it difficult to determine if an area is composed of water, ice, or wet snow cover. Specialized software is employed to analyze the images, which are often combined with digital elevation models (3D representations of terrains) to add geocoding information, but a human eye is necessary to make the final judgment call about the details of the lake border on the map.

Photograph of the Weingarten glacier lake in Switzerland with GPS path in red. (From: Strozzi et al., 2012)

Dr. Strozzi and his team looked at three glacial areas (in Switzerland, Tajikistan, and Nepal) to determine the changing nature of glacial lakes and to test the SAR technology. In Switzerland and Nepal, teams travelled to the lake sites to make on-the-ground comparisons to the SAR satellite images. The results show that the SAR imaging is of high enough quality to make assessments in changes in lake shapes. And when used in conjunction with other optical and land-based information sources, can be used as a hazard predictor in glacial regions.

In addition to flood prevention, the results can also be uploaded into Google Earth, which accepts changes to mapped features to keep information as actual as possible. This contributes to a genuine visual guide to the planet, while at the same time keeping people safe from the hazards lurking from above.

By Amanda Gläser-Bligh, geologist and member of ELEEP, Emerging Leaders in Environmental and Energy Policy Network