CR
Cryospheric Sciences

Sophie Berger

Sophie Berger is a PhD student of the glaciology unit, at the Université Libre de Bruxelles (ULB), Brussels Belgium. She is using various remote sensing data and techniques to investigate the dynamics and stability of the ice shelves in Dronning Maud Land (East Antarctica).
She tweets as @SoBrgr.

Image of the Week – Mushrooms at zero degrees = hair ice?!

Image of the Week – Mushrooms at zero degrees = hair ice?!

 

When you go down to the woods today you’re in for a big surprise….. hair ice! 

Did you know that there is a type of ice called hair ice? It is shaped like fine, silky hairs and looks like white candy floss. It grows on the rotten branches of broad-leaf trees during humid winter nights when the air temperature drops slightly below 0°C. A 100-year-old theory states that hair ice also needs something else to grow – a fungus – but, until recently, no one had managed to confirm this.

A team of scientists (a physicist, a chemist and a biologist) in Germany and Switzerland have now identified the missing ingredient – the fungus Exidiopsis effusa – after performing a series of experiments (Hofmann et al, 2015).

The biologist, Gisela Preuß, studied samples of hair-ice wood under the microscope and discovered that all of them were home to Exidiopsis effusa. If the fungus was missing or its activity stopped by fungicide or hot water, the hair ice would be missing too. The physicist, Christian Mätzler, studied the physical mechanism that makes hair ice grow in such fine strands. He discovered that the shape of the ice is due to the internal structure (rays) of the wood and growth of the fungus, which together prevent the ice from forming large crystals at the wood surface. The chemist, Diana Hofmann, studied the hair ice itself and identified natural substances produced by the fungus – lignin and tannin – that allow the hair ice to keep its hairy shape for a long time. This collaboration between scientists from different fields really shows the power of putting your heads together!

It took 100 years to confirm the theory because hair ice is rare and hard to spot: it mostly forms during the night, melting when the sun rises.

So…keep an eye out next time you go for an early morning walk in the woods. If you can find hair ice, you are in for a treat!

 


Reference/further reading

 

planet_pressThis is modified version of a “planet press” article written by Bárbara Ferreira and originally published on 22 July 2015 on the EGU website
(Hungarian, Portuguese, Serbian and Spanish versions are also available, why not considering adding a new language to the list? 🙂 )

 

Image of the Week — Glowing Ice

Image of the Week — Glowing Ice

Two weeks ago, the EGU General Assembly was coming to an end in Vienna. With over 16,500 participants, this year’s edition was bigger and more varied than ever (e.g check out this good overview of the science-policy short course, published 2 days ago on geolog). The week was particularly fruitful for the cryospheric sciences and to mark this we have cherry-picked one of the winning picture of the EGU photo contest 2016 as our image of this week. It’s great that an image of the cryosphere is a winner in this competition and we are pleased to see that it isn’t only us that go bananas for pictures of ice!

What do we see?

The beautiful shot shows a stranded block of ice on the shore the glacial lagoon Jökulsárlón, south-east Iceland. Ice calves off Breiðamerkurjökull, an outlet glacier which flows out from Vatnajökull, the ice cap which makes up the largest ice body of Iceland. Jökulsárlón developed as Breiðamerkurjökull retreated away from the Atlantic ocean (into which it flows) and the lagoon continues to grow in size as the glacier continues to retreat (see image below).

Panorama of the Jökulsárlón glacial lake, Iceland, 2010. [Credit: Ira Goldstein (via wikimedia commons)]

Panorama of the Jökulsárlón glacial lake, Iceland, 2010. [Credit: Ira Goldstein (distibuted via wikimedia commons)]


The image comes from imaggeo, what is it?

You like this image of the week? Good news, you are free to re-use it in your presentation and publication because it comes from Imaggeo, the EGU open access image repository.

(Edited by Emma Smith)

Image Of The Week – Do My Ice Deceive Me?

Image Of The Week – Do My Ice Deceive Me?

A few weeks ago, we focussed our image of the week on very particular parts of Antarctica, which display blue ice at the surface.

Today we would like to put the spotlight on an even more extreme chromatic phenomenon : the Fyndið ísjaki Brandari (should be pronounced “/fɪːntɪð/ˈiːsjacɪ /ˈprantaːrɪ/“, even though a bit of phonetics never hurt anyone, for the sake of simplicity this phenomenon will be referred to as the FIB).

Despite our poor understanding of the FIB, this phenomenon has been recognised since ancient times. According to Icelandic folklore, FIB has been observed in remote regions at the centre of ice sheets and ice caps for many hundreds of years and was originally thought to indicate a unicorn breeding ground. However, recent studies have begun to find a more scientific explanation for this truly wonderful phenomenon.

Dr Joe Kerr, the world specialist of FIB, told us that the presented picture was an exceptional shot because colour changes, known as Layered Ice Extraordinaire (LIE), are aligned with isochronic layers, indicating a time-dependant source for the changes in colour. He even concluded that this specific FIB shows indications of originating from ice which has travelled to Iceland from tropical regions, although more thorough dating (using a new mobile software package known as TINDER) of the layering must take place to confirm this.

On the other hand, Prof Han-Ki Ding, a competitor for the title of FIB world specialist, also inspected the picture and does not agree with his colleague Joe Kerr. Han-Ki Ding, hypothesises that the thick layer of white snow on top of the coloured layers is indicative of ice of a polar origin. He even added that the snow layer that is sagging on the left part of the image provides further evidence. Recordings of a high pitched noise, know as an “ice scream“, were made when the snow collapsed into its current position. Careful analysis showed that in this particular case the collapse emitted a “coo kiedough” ice scream – indicative of ice originating at high latitudes.

Of course we could further discuss the connection between the FIB and unicorn breeding grounds but then our story would not be plausible anymore, and you might realise that today is April Fools Day… Anyway we thank you – the readers – for wasting a few minutes of your time reading this entirely uninformative post and we hope it made you smile in the process 🙂

Edited by  Emma Smith and Nanna Karlsson

Image of the Week – Monitoring icy rivers from space!

Image of the Week – Monitoring icy rivers from space!
Ice and floodwater inundate a town in Alaska because an ice jam formed downstream (credit: U.S. National Park Service on Wikimedia Commons)

Ice and floodwater inundate a town in Alaska because an ice jam formed downstream (credit: U.S. National Park Service)

Why?

When a river freezes over, it changes the amount of water that flows through the river system. River ice affects many of the world’s largest rivers, and in the Northern Hemisphere, approximately 60% of rivers experience significant seasonal effects. The formation and evolution of river ice changes river discharge and is not only of interest to local ice skating enthusiasts. The variations in river discharge can lead to severe situations, such as ice jams/dams (with an accompanying risk of flooding), or issues that affect the management of hydroelectric power plant infrastructures.

How?

Satellite data have a huge potential for river ice monitoring thanks to the capability of imaging large areas. Synthetic Aperture Radar (SAR) systems are particularly promising as they can acquire data day or night without regard to cloud cover. In this way the extent of river ice can be mapped in great detail. The image of this week was produced applying one specific SAR technique : the polarimetry.

What?

The image of this week is a false color composite with the different polarimetric channels (red = HH, green = HV and blue = VV) of RADARSAT-2 images. The nature of the ground/ice surface will influence the way the waves sent by the radar interact with it and thus the value of the backscattered signal in different polarisation. The pattern on the left image was then introduced in an algorithm to automatically retrieve different types of ice (right image). Recognising ice types from space is an essential step to monitor and then predict processes such as ice dam collapses.

Los_Vistula_river-ice-illustration_typesjpg

Photo-interpretation key of the different types of ice, after Pawłowski et al (2015)

Reference

Pawłowski B., Łoś H., Osińska-Skotak K. (2015) The first approach of ice filling and river ice cover types classification for the lower Vistula River based on satellite SAR data. Monografie Komisji Hydrologicznej PTG ; t. 3, pp. 313-324.

Also check out:

This previous image of the week on SAR polarimetry applied to sea ice

The image of last week about another type of ice dam, at the terminus of a glacier

Image of the Week — Last Glacial Maximum in Europe

Image of the Week — Last Glacial Maximum in Europe

During the last ice age*, ~70,000 to 20,000 years ago, the climate was much colder in Europe.

As a result, the northern part of Europe was fully covered by the Fennoscandian (a.k.a the Scandinavian ) ice sheet, which extended up to the British Isles and some parts of Poland and Germany. In central Europe, the Alps were also almost fully glaciated.

The storage of all this ice on the continent lowered the sea level (seedark green), which substantially reduced the extent of the North Sea.

*This period is referred to as the Weichselian glaciation and the Würm glaciation in Northern Europe and the Alps, respectively.

 

More information

A more complete and accurate dataset (including GIS maps) of Europe during the last glacial maximum is freely available :

Becker, D., Verheul, J., Zickel, M., Willmes, C. (2015): LGM paleoenvironment of Europe – Map. CRC806-Database, DOI: http://dx.doi.org/10.5880/SFB806.15

LGM_Europe_Map_v1

 

Image of the Week – Antarctic fieldwork 50 years ago!

Image of the Week – Antarctic fieldwork 50 years ago!

So far this blog has published many pictures of current polar field work campaigns. Today, we would like to take you back to Antarctic expeditions during the 1960s. The photos presented in this post date back from the Belgian-Dutch Antarctic field campaigns of 1964-1966.

The first picture shows Ken Blaiklock (red overalls) with a Belgian surveyor. Ken was part of the 1955–58 Commonwealth Trans-Antarctic Expedition – completing the first overland Antarctic crossing via the south pole. This shot was taken during the 1964-1965 summer campaign, as they were surveying the displacement of glaciers in the Sør Rondane Mountains, East Antarctica.  At that time, the men had to leave the base station for three weeks with two dog-sled pulled by a small skidoo-like vehicle. Remarkably, this shot doesn’t look too dissimilar to many field campaigns today, where the same type of sledges are still used and the clothing worn is also very similar. However, logistical support was very different, with no technicians or field guides those who were part of the polar expeditions of 50 years ago had to be experts at everything!

The second picture illustrates how precise positions (and relative displacements) were measured at that time. No fancy GPS technology, but a network of markers and theodolites. The shot was taken on a pinning point, close to the front of the Roi Baudouin Ice shelf, during the overwintering campaign of 1965 (where people had to stay in Antarctica for 15 months).

A geodesist measuring the precision position of a marker with his theodolite, overwintering campaign in Antarctica, 1965. (Credit: Jean-Jacques Derwael)

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Image of the Week — Happy ValentICE’s day

Image of the Week — Happy ValentICE’s day

On the eve of 14 February, love and little hearts are everywhere, even trapped in lake ice!
The EGU Cryosphere blog team wishes you a happy Valentine’s Day 🙂

Behind this nice picture, there is also science

This picture was taken during a laboratory experiment that aimed to reproduce the bubbles observed in Arctic lake ice in the winter.

In this shot, we can see two types of gas bubbles in the ice. The elongated vertical bubbles are formed after the exsolution of gas at the water-ice interface. The gas present in “heart-shaped” bubbles originates from ebullition (i.e. it has been emitted as bubbles from the sediment) and it contains a large amount of methane, a significant greenhouse gas. In both cases, the gas is trapped in the ice during the downward evolution* of the freezing front but the shape and gas content of the bubbles largely depends on the velocity of the freezing front development.

The goal of this research is to better understand the origin of the methane emitted by Artic lakes and unravel the role of lake ice cover on the methane atmospheric burden.

*During the winter, the cold atmosphere cools down the water of the lake, when the freezing point is reached, a thin layer of layer of lake ice starts to form at the surface and extends downward.

Further reading/Reference

Boereboom, T., Depoorter, M., Coppens, S., and Tison, J.-L.: Gas properties of winter lake ice in Northern Sweden: implication for carbon gas release, Biogeosciences, 9, 827-838, doi:10.5194/bg-9-827-2012, 2012.

Sapart, C. J et al (in preparation).

Image of the Week — slush on top of sea ice

Image of the Week — slush on top of sea ice

Many glaciologists look forward to going on fieldtrips and then, once they are back, they make us dream by posting breathtaking photos (like THIS or THIS or THIS). However, the reality of the field can sometimes be very different….

The picture illustrates how difficult it can be to work on sea ice when the snow on top of it starts to melt and forms slush (a mixture of snow and liquid water that looks very much like an Italian granita).

Here, the sled carrying the field equipment is half drowned in the slush while the technician who came to the rescue (with his skidoo in the back) is also sunk.

On this blog post you can read about another expedition of M. Kotovitch on sea ice.

Edited by Emma Smith

 

Image of the Week — Greenland ice sheet and clouds

Image of the Week — Greenland ice sheet and clouds

A new study combining satellite observations and model simulations shows that clouds increase meltwater runoff in Greenland by one-third compared to a cloud-free scenario.

Precipitation effects not considered, clouds above the Greenland ice sheet reduce its Surface Mass Balance (SMB) [red in figure] compared to clear-sky conditions [blue in figure]. Because clouds trap the outgoing radiation from the ice-sheet surface, they locally warm the atmosphere below, which reduces Greenland’s meltwater refreezing at night. Hence, clouds increase runoff from the ice sheet by 56 billion tons of water each year.

Reference/further reading:

  • Van Tricht, K., S. Lhermitte, J. T. M. Lenaerts, I. V. Gorodetskaya, T. S. L’Ecuyer, B. Noël, M. R. van den Broeke, D. D. Turner, and N. P. M. van Lipzig. 2016. “Clouds Enhance Greenland Ice Sheet Meltwater Runoff.” Nature Communications 7 (January). Nature Publishing Group: 10266. doi:10.1038/ncomms10266.
  • Article in the Washington Post about the paper.
  • You can follow Kristof Van Tricht the study’s lead author on twitter @kristofvt.

Image of the Week — Happy New Year

Image of the Week — Happy New Year

December 2014, 11:50 p.m., the sun licks the horizon on Derwael ice rise; It’s time to go back to the tent …

The shot was taken during the 2014 IceCon Field campaign in East Antarctica (read Brice’s blog post  telllling about his first journey to Antarctica).

Here, you can also read about the 2016 field season of the IceCon project, which started just a few days ago.