GeoLog

glacier

Imaggeo on Mondays: Concord at midnight

Imaggeo on Mondays: Concord at midnight

The high peaks of the Alps are always awe inspiring, but this midnight shot, captured by Alessandro Lechmann, a PhD student at the Institute of Geological Sciences at the University of Bern, further enhance their fragile beauty. With a warming climate threatening snow availability to even the highest peaks, it has never been more important to appreciate the importance of the glaciers which drape the mountain slopes.

This photograph shows a view from the Jungfraujoch (a saddle in the Bernese Alps, connecting the two four-thousander peaks Jungfrau and Mönch, at an elevation of 3,466 metres above sea level) towards the south-east down the Jungfraufirn (an arm of the Great Altesch Glacier).

Originating amidst three of the most famous mountains of the Swiss Alps (Eiger, Mönch and Jungfrau), this glacier flows southwards towards the Concordiaplatz, where it merges with the Ewigschneefäld and the Great Aletschfirn into the Great Aletsch Glacier. Even today, despite reports of receding glaciers in the Alps, it forms the largest and longest Alpine glacier.

In the countries surrounding the Alps, glacial landforms dominate the landscape. From drumlins, moraines (accumulations of glacial debris) and overdeepenings in the foreland to U-shaped valleys (Lauterbrunnen is a marvellous example) and cirques in mountainous regions. Although retreating at rates not seen previously, these glaciers carved the face of central Europe during the last glacial-interglacial cycles.

The building of the railway to the Jungfraujoch research station started in 1896 and was completed in 1912; an impressive feat considering the limited technology before the First World War. Perched precariously 3500 m above sea level, the research station (known for its prominent sphinx observatory), has contributed significantly   to the understanding of the atmospheric sciences, glaciology and cosmic ray physics.

The ridge which the Jungfraujoch is built on, marks the northern margin of the exposed crystalline core of the Alpine orogeny. Interestingly, this mountain ridge, in addition to being a geological boundary, is also a major watershed. Rain that falls north, flows via the Aare into the Rhine, which eventually discharges into the North Sea. Precipitation on the southern flank and melt water from the Jungfraufirn, on the other hand, joins the Rhone in the Valais valley, that ends up in the Mediterranean Sea. This highlights the importance of Alpine glaciers as a water stores which continue to provide water throughout the year.

By Alessandro Lechmann PhD student at the Institute of Geological Sciences at the University of Bern

Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their photographs and videos to this repository and, since it is open access, these images can be used for free by scientists for their presentations or publications, by educators and the general public, and some images can even be used freely for commercial purposes. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. Submit your photos at http://imaggeo.egu.eu/upload/.

The best of Imaggeo in 2016: in pictures

The best of Imaggeo in 2016: in pictures

Imaggeo, our open access image repository, is packed with beautiful images showcasing the best of the Earth, space and planetary sciences. Throughout the year we use the photographs submitted to the repository to illustrate our social media and blog posts.

For the past few years we’ve celebrated the end of the year by rounding-up some of the best Imaggeo images. But it’s no easy task to pick which of the featured images are the best! Instead, we turned the job over to you!  We compiled a Facebook album which included all the images we’ve used  as header images across our social media channels and on Imaggeo on Mondays blog post in 2016 an asked you to vote for your favourites.

Today’s blog post rounds-up the best 12 images of Imaggeo in 2016, as chosen by you, our readers.

Of course, these are only a few of the very special images we highlighted in 2016, but take a look at our image repository, Imaggeo, for many other spectacular geo-themed pictures, including the winning images of the 2016 Photo Contest. The competition will be running again this year, so if you’ve got a flare for photography or have managed to capture a unique field work moment, consider uploading your images to Imaggeo and entering the 2017 Photo Contest.

Blue Svartisen . Credit: Kay Helfricht (distributed via imaggeo.egu.eu)

When you think of a glacier the image you likely conjure up in your mind is that of bright white, icy body. So why do some glaciers, like Engabreen, a glacier in Norway, sometimes appear blue? Is it a trick of the light or some other phenomenon which causes this glacier to look so unusual?  You can learn all about it in this October post over on GeoLog.

 

‘There is never enough time to count all the stars that you want.’ . Credit: Vytas Huth (distributed via imaggeo.egu.eu). The centre of the Milky Way taken near Krakow am See, Germany. Some of the least light-polluted atmosphere of the northern german lowlands.

Among the winning images of our annual photo contest was a stunning night-sky panorama by Vytas Huth; we aren’t surprised it has been chosen as one of the most popular images of 2016 too. In this post, Vytas describes how he captured the image and how the remote location in Southern Germany is one of the few (in Europe) where it is still possible to, clearly, image the Milk Way.

 

“Above the foggy strip, this white arch was shining, covering one third of the visible sky in the direction of the ship's bow,” he explains. “It was a so-called white, or fog rainbow, which appears on the fog droplets, which are much smaller then rain droplets and cause different optic effects, which is a reason of its white colour.”

Gateway to the Arctic . Credit: Mikhail Varentsov (distributed via imaggeo.egu.eu)

“Above the foggy strip, this white arch was shining, covering one third of the visible sky in the direction of the ship’s bow,” describes Mikhail Varentsov, a climate and meteorology expert from the University of Moscow. “It was a so-called white, or fog rainbow, which appears on the fog droplets, which are much smaller then rain droplets and cause different optic effects, which is a reason of its white colour.” Mikhail captured the white rainbow while aboard the Akademik Tryoshnikov research vessel during its scientific cruise to study the effects of climate change on the Arctic.

 

History. Credit: Florian Fuchs (distributed via imaggeo.egu.eu)

The header image, History by Florian Fuchs, we used across our social media channels was popular with our Facebook followers, who chose it as one of the best of this year. The picture features La Tarta del Teide – a stratigraphic section through volcanic deposits of the Teide volcano on Tenerife, Canary Islands.

 

Find a new way . Credit: Wolfgang Fraedrich (distributed via imaggeo.egu.eu)

Lavas erupted into river waters, and as a result cooled very quickly, can give rise to fractures in volcanic rocks. They form prismatic structures which can be arranged in all kinds of patterns: horizontally (locally known as the woodpile), slightly arching (the harp) and in a radial configuration known as the rosette. The most common configuration is the ‘organ pile’ where vertical fractures form. These impressive structures are seen in the walls of the Gole dell ‘Alcantara, a system of gorges formed 8,000 years ago in the course of the river Alcantara in eastern Sicily.

 

Home Sweet Home . Credit: André Nuber (distributed via imaggeo.egu.eu)

Can you imagine camping atop some of the highest mountains in Europe and waking up to a view of snowcapped peaks, deep valleys and endless blue skies? This paints an idyllic picture; field work definitely takes Earth scientists to some of the most beautiful corners of the planet.

 

Isolated Storm . Credit: Peter Huber (distributed via imaggeo.egu.eu)

In November 2016 we featured this photograph of an isolated thunderstorm in the Weinviertel in April. The view is towards the Lower Carpathian Mountains and Bratislava about 50 kilometers from Vienna. Why do storms and isolated thunderstorms form? Find out in this post.

 

Glacial erratic rocks . Credit: Yuval Sadeh (distributed via imaggeo.egu.eu)

As glaciers move, they accumulate debris underneath their surface. As the vast frozen rivers advance, they carry the debris, which can range from pebble-sized rocks through to house-sized boulders, along with it. As the climate in the Yosemite region began to warm as the ice age came to an end, the glaciers slowly melted. Once all the ice was gone, the rocks and boulders, known as glacial erratics, were left behind.

 

Snow and ash in Iceland . Credit: Daniel Garcia Castellanos (distributed via imaggeo.egu.eu)

Icelandic snow-capped peaks are also sprinkled by a light dusting of volcanic ash in this photograph. Dive into this March 2016 post to find out the source of the ash and more detail about the striking peak.

 

Living Flows . Credit: Marc Girons Lopez (distributed via imaggeo.egu.eu)

There are handful true wildernesses left on the planet. Only a few, far flung corners, of the globe remain truly remote and unspoilt. To explore and experience untouched landscapes you might find yourself making the journey to the dunes in Sossuvlei in Namibia, or to the salty plain of the Salar Uyuni in Bolivia. But it’s not necessary to travel so far to discover an area where humans have, so far, left little mark. One of the last wilds is right here in Europe, in the northern territories of Sweden. This spectacular photograph of the Laitaure Delta is brought to you by Marc Girons Lopez, one of the winners of the 2016 edition of the EGU’s Photo Contest!

 


The power of ice. Credit: Romain Schläppy, (distributed via imaggeo.egu.eu).

The January 2016 header image across our social media was The Power of Ice, by Romain Schlappy. This vivid picture was captured from a helicopter by Romain Schläppy during a field trip in September 2011. You can learn more about this image by reading a previous imaggeo on mondays post.

 

Sea of Clouds over Uummannaq Fjord. Credit: Tun Jan Young (distributed via imaggeo.egu.eu)

The current header image, Sea of Clouds over Uummannaq Fjord by Tun Jan Young, is also a hit with our followers and the final most popular image from Imaggeo in 2016. A sudden change of pressure system caused clouds to form on the surface of the Uummannaq Fjord, Northwestern Greenland, shrouding the environment in mystery.

 

If you pre-register for the 2017 General Assembly (Vienna, 22 – 28 April), you can take part in our annual photo competition! From 1 February up until 1 March, every participant pre-registered for the General Assembly can submit up three original photos and one moving image related to the Earth, planetary, and space sciences in competition for free registration to next year’s General Assembly!  These can include fantastic field photos, a stunning shot of your favourite thin section, what you’ve captured out on holiday or under the electron microscope – if it’s geoscientific, it fits the bill. Find out more about how to take part at http://imaggeo.egu.eu/photo-contest/information/.

 

Imaggeo on Mondays: Glacier de la Pilatte

Imaggeo on Mondays: Glacier de la Pilatte

The relentless retreat of glaciers, globally, is widely studied and reported. The causes for the loss of these precious landforms are complex and the dynamics which govern them difficult to unravel. So are the consequences and impacts of reduced glacial extent atop the world’s high peaks, as Alexis Merlaud, explains in this week’s edition of Imaggeo on Mondays.

This picture was taken on 20 August 2009 at the Pilatte Hutt (44.87° N, 6.33° E,  2572 m.a.s.l.), located in the massif des Ecrins in the French Alps. It shows the Pilatte Glacier, which  was recently described as being 2.64km2 wide and 2.6 km long.

As most of the glaciers in the world, the Pilatte Glacier has been retreating over the last decades as can be seen from the two pictures in figure 1, taken respectively in 1921 and 2003, and from quantitative measurements since the 19th century. The glacier has lost 1.8 km since the end of the Little Ice Age (1850).

Figure 1: Retreat of the Pilatte Glacier over the last decades (pictures adapted from Bonet et al, 2005, time series from Reynaud and Vincent, 2000).

Figure 1: Retreat of the Pilatte Glacier over the last decades (pictures adapted from Bonet et al, 2005, time series from Reynaud and Vincent, 2000).

Two climatic variables affect glacier extents in opposite directions: the amount of winter precipitations (which accumulates snow converting to ice on the glacier) and the summer temperatures (which determines the melting altitude and thus the glacier ablation area – the zone where ice is lost from the glacier, commonly via melting).

The initial retreat of the Alpine glaciers in the 19th century can’t be explained by summer temperatures which remained stable until the 20th century. It has thus been explained by a reduction in snowfall . On the other hand, a recent study suggests that industrial black carbon could have triggered the end of the little ice age in Europe, by reducing the glaciers’albedo. But the globally observed glacier retreat from the 20th century is attributed to the increasing summer temperatures.

Figure 2: Global mean temperature series (Oerlemans, 2005, supporting online material)

Figure 2: Global mean temperature series (Oerlemans, 2005, supporting online material)

Understanding the relationship between glacier dynamics and climate enables to use glacier extents  as proxies to reconstruct global temperature time series, as was done by Oerlemans (2005). Using 169 glacier across the globe, this study provided independent evidences on the timing and magnitude of the warming, that are useful to corroborate other time series obtained through other proxies (such as tree rings) or by direct temperature measurements (see Figure. 2), all showing a temperature increase by around 0.5K across the 20th century.

Glaciers continued to retreat in the 20th century, at an accelerating rate. In the 2015 foreword of the Bulletin of the World Glacier Monitoring Service, its director Michael Zemp writes: “The record ice loss of  the 20thcentury, observed in 1998, was exceeded in 2003, 2006, 2011, 2013, and probably again in 2014 (based on the ‘reference’ glacier sample)”. Using climate models, it appears now possible to distinguish an increasing anthropogenic signature in this phenomenon.

Figure 3: Average glacier retreat worldwide from 1980 in mm of water equivalent (mm.w.e), a unit representing the average thickness of a glacier (WGMS website)

Figure 3: Average glacier retreat worldwide from 1980 in mm of water equivalent (mm.w.e), a unit representing the average thickness of a glacier (WGMS website)

One of the many problems caused by glaciers depletion is the impact on water supplies: glaciers are huge reservoirs of fresh water and their vanishings affect drinking water stock and irrigation for the neighboring population. In the Alps, the idea of replacing the glaciers by dams is already studied. This solution would probably be more difficult to implement in other parts of the world, such as in nothern Pakistan, an area covered with over 5000 glaciers, whose melting is already problematic, causing in particular severe floods.

 

By Alexis Merlaud, Belgian Institute for Space Aeronomy, Brussels, Belgium

References

Bonet, R., Arnaud, F., Bodin, X., Bouche, M., Boulangeat, I., Bourdeau, P., … Thuiller, W. (2015). Indicators of climate: Ecrins National Park participates in long-term monitoring to help determine the effects of climate change. Eco.mont (Journal on Protected Mountain Areas Research), 8(1), 44–52. http://doi.org/10.1553/eco.mont-8-1s44

Ravanel, L., Dubois, L., Fabre, S., Duvillard, P.-A., & Deline, P. (2015). The destabilization of the Pilatte hut (2577 m a.s.l. – Ecrins massif, France), a paraglacial process? EGU General Assembly 2015, Held 12-17 April, 2015 in Vienna, Austria.  id.8720, 17.

Reynaud, L., Vincent, C., & Vincent, C. (2000). Relevés de fluctuations sur quelques glaciers des Alpes Françaises. La Houille Blanche, (5), 79–86. http://doi.org/10.1051/lhb/2000052

Pointer, T. H., Flanner, M. G., Kaser, G., Marzeion, B., VanCuren, R. A., & Abdalati, W. (2013). End of the Little Ice Age in the Alps forced by industrial black carbon. Proceedings of the National Academy of Sciences of the United States of America, 110(38), 15216–21. http://doi.org/10.1073/pnas.1302570110

Vincent, C., Le Meur, E., Six, D., & Funk, M. (2005). Solving the paradox of the end of the Little Ice Age in the Alps. Geophysical Research Letters, 32(9), L09706. http://doi.org/10.1029/2005GL022552

Oerlemans, J. (2005). Extracting a climate signal from 169 glacier records. Science (New York, N.Y.), 308(5722), 675–7. http://doi.org/10.1126/science.1107046

Farinotti, D., Pistocchi, A., Huss, M., al, A. A. et, Barnett T P, A. J. C. and L. D. P., Bavay M, L. M. J. T. and L. H., … Zemp M, H. W. H. M. and P. F. (2016). From dwindling ice to headwater lakes: could dams replace glaciers in the European Alps? Environmental Research Letters, 11(5), 054022. http://doi.org/10.1088/1748-9326/11/5/054022

Marzeion, B., Cogley, J. G., Richter, K., Parkes, D., Gregory, J. M., White, N. J., … Adams, W. (2014). Glaciers. Attribution of global glacier mass loss to anthropogenic and natural causes. Science (New York, N.Y.), 345(6199), 919–21. http://doi.org/10.1126/science.1254702

WGMS (2008): Global Glacier Changes: facts and figures. Zemp, M., Roer, I., Kääb, A., Hoelzle, M., Paul, F. and Haeberli, W. (eds.), UNEP, World Glacier Monitoring Service, Zurich, Switzerland: 88 pp

 

Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their photographs and videos to this repository and, since it is open access, these images can be used for free by scientists for their presentations or publications, by educators and the general public, and some images can even be used freely for commercial purposes. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. Submit your photos at http://imaggeo.egu.eu/upload/

Imaggeo on Mondays: Rock glaciers

Imaggeo on Mondays: Rock glaciers

Picture a glacier and you probably imagine a vast, dense mass of slow moving ice; the likes of which you’d expect to see atop the planet’s high peaks and at high latitudes. Now, what if not all glaciers look like that?

Take some ice, mix in some rock, snow and maybe a little mud and the result is a rock glacier. Unlike ice glaciers (the ones we are most familiar with), rock glaciers have very little ice at the surface. Instead, the ice is locked in between the other components, or forms a solid, central structure. Looking at the rock glacier on the flanks of the Heart Peaks shield volcano in northwestern British Columbia (pictured above) you’d be forgiven for thinking this isn’t a glacier at all!

Rock glaciers move down slopes, slowly; typically at speeds which range from a few millimetres per year, up to a few meters. The movement is driven by gravity and usually due to gliding at the base of the glacier, or sometimes due to internal deformation of the ice.

How do the impressive landforms come about? The jury is still out, with the merits of a number of explanations still being debated. Some argue that they are due to geomorphic processes that result from seasonal thawing of snow in areas of permafrost; while others suggest the explanation is simpler: as a glacier wastes, it leaves behind an increasing amount of rock debris as the ice melts. It may be that rock glaciers are the result of a landslide covered glacier melting, or the mixing of a glacier with a landslide it encounters in its way down-slope…

Whatever the exact cause of the rock glacier on the flank of Hearts Peak, it remains a particularly striking example of the landform, given its unusual pink(ish) colour. The dormant volcano is characterised by steep-sided lava domes which are composed of porphyitic rhyolites  and, to a lesser extent, trachytic rocks, which give rise to the unusual colouring of this rock glacier.

Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their photographs and videos to this repository and, since it is open access, these images can be used for free by scientists for their presentations or publications, by educators and the general public, and some images can even be used freely for commercial purposes. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. Submit your photos at http://imaggeo.egu.eu/upload/.

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