CR
Cryospheric Sciences

Image of the Week

Image of the Week – How ocean tides affect ice flow

July 8, 2016
Image of the Week – How ocean tides affect ice flow
(a) Shaded relief map of Rutford Ice Stream (West Antarctica) and surrounding area. Red box indicates the region shown in b. (b) Horizontal velocity where colors indicate speed, arrows show flow direction, and grayscale background is horizontal speed from Rignot et al. (2011). (c) Detrended along-flow displacements measured with GPS stations beginning December 2003. Locations of stations are indicated in (b). ( Credit : Brent Minchew )

Ice streams discharge approximately 90% of the Antarctic ice onto ice shelves , and ultimately into the sea into the sea (Bamber et al., 2000; Rignot et al., 2011). Whilst flow-speed changes on annual timescales are frequently discussed, we consider here what happens on much shorter timescales! Previous studies have shown that ice streams can respond to ocean tides at distances up to 100km inland ...[Read More]

Image of The Week – A Game of Drones (Part 1: A Debris-Covered Glacier)

July 1, 2016
Image of The Week – A Game of Drones (Part 1: A Debris-Covered Glacier)
Figure 1: Down-glacier view of debris-covered Miage Glacier, Italy, taken from a low-altitude lightweight UAV in June 2016 (Credit: M. Westoby). As the summer progresses, the melting of winter snow cover prompts the development of a surface drainage network, characterised as a network of streams and ponds, which are concentrated in intermoraine troughs and drain into open crevasses or moulins. Snowmelt in this area will eventually reveal a glacier surface covered by a continuous mantle of supraglacial debris, comprised predominantly of mica-schist

What are debris-covered glaciers? Many alpine glaciers are covered with a layer of surface debris (rock and sediment), which is sourced primarily from glacier headwalls and valley flanks. So-called ‘debris-covered glaciers’ are found in most glacierized regions, with concentrations in the European Alps, the Caucasus, Hindu-Kush-Himalaya, Karakoram and Tien Shan, the Andes, and Alaska and the weste ...[Read More]

Image of the Week – Canyons Under The Greenland Ice Sheet!

June 24, 2016
Image of the Week – Canyons Under The Greenland Ice Sheet!
Figure 1: The calculated drainage network for southern Greenland (interpreted from airbourne ice penetrating radar data). It shows an extensive flow network of channels beneath the ice. Which can be interpreted as a possible configuration for water flow pre-glacially, as well as in an ice-free future. The main channel within the catchment area of Jakobshavn Isbræ is marked by the red line. Bed elevation (between 300 and 1300 m above sea level (asl)) is also shown. Inset: location of study area within Greenland.

The Greenland Ice Sheet contains enough water to raise sea level by 7.36 meters (Bamber, et. al. 2013) and much of this moves from the interior of the continent into the oceans via Jakobshavn Isbræ – Greenland’s fastest flowing outlet glacier. An ancient river basin hidden beneath the Greenland Ice Sheet, discovered by researchers at the University of Bristol, may help explain the loca ...[Read More]

Image of The Week – Ballooning on the Ice

June 17, 2016
Image of The Week – Ballooning on the Ice
One man and his balloon. Field leader Prof. J. P. Steffensen (Centre for Ice and Climate, University of Copenhagen) in front of one of the balloons used in camp. Credit: S. Kipfstuhl.

A curious experiment is taking place in Greenland. An experiment involving very large balloons and – of course – a lot of snow. Read on to discover why balloons are an environmentally friendly tool when constructing an ice core drill camp. Last year, a small team traversed 400km from northwest Greenland to the EastGRIP site (read more about the traverse here). This year another strenuous task is w ...[Read More]

Image of the week — The warming effect of the decline of Arctic Sea Ice

June 10, 2016
Image of the week — The warming effect of the decline of Arctic Sea Ice
Decreasing sea ice and its effect on the albedo in the Arctic (credit: I. Eisenman, K. Pistone, V. Ramanathan, and NASA/GSFC Scientific Visualization Studio)

One of the most dramatic signals of Earth’s recent warming has been the precipitous decline of the Arctic sea ice. While the sea-ice decline is in response to warming ocean and atmosphere, it also has an important feed-back on the climate itself. Solar radiation and albedo Earth’s main energy source is solar radiation. This solar radiation is either absorbed in the atmosphere or at the ...[Read More]

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

June 3, 2016
Image of the Week – Mushrooms at zero degrees = hair ice?!
Hair ice in a forest near Moosseedorf, Switzerland (Credit: Christian Mätzler)

  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 a ...[Read More]

Image of the Week — Historical aerial imagery of Greenland

May 27, 2016
Image of the Week — Historical aerial imagery of Greenland
Aerial photo of the Zackenberg delta in North-East Greenland taken in 1932. (Credit: Danish Geodata Agency)

A few month ago, we were taking you on a trip back to Antarctic fieldwork 50 years ago, today we go back to Greenland during 1930s! When geopolitics serves cryospheric sciences The Permanent Court of International Justice in The Hague awarded Danish sovereignty over Greenland in 1933 and besides geopolitical interests, Denmark had a keen interest in searching for natural resources and new opportun ...[Read More]

Image of The Week – Tumbling Rocks

May 20, 2016
Image of The Week – Tumbling Rocks
A 15,000 m³ rockfall during the 2015 summer heat wave at Tour de Ronde summit, Mont Blanc Massif. (Photo credit: Ludovic Ravanel.)

This photo captures a rockfall at the summit of Tour de Ronde, 3792 m above sea level in the Mont Blanc Massif. On 27 August 2015, around 15000 m3  of rock fell from the steep walls of the mountain. Why do mountains crumble ? Rockfalls such as the one on the photo have been linked to thawing permafrost. The exact mechanism that leads to these events is not fully understood, however, it is thought ...[Read More]

Image of the Week – See How Seasonal Sea Ice Decline Differs!

May 13, 2016
Image of the Week – See How Seasonal Sea Ice Decline Differs!
Figure 1: Arctic sea-ice area (75°N to 90°N) VS global annual mean surface air temperature for the complex model MPI-ESM-LR. Red dots represent a seasonal average over autumn (September/October/November) and blue dots over spring (March/April/May) of a particular year in the historical and future (RCP8.5) simulations. The dotted black lines result from a linear orthogonal regression in the ice area regime with the steepest change (Credit: subset of fig 2 from Bathiany et al, 2016 ).

Why do we care about sea ice in the first place? Sea ice is important for several components of the climate system. Due to its high albedo, sea ice reflects a high amount of the incoming solar radiation and is therefore relevant for the Earth’s energy budget. Sea ice inhibits the exchange of heat, moisture and momentum between ocean and atmosphere, which usually occur at the sea surface. Whe ...[Read More]

Image of the Week — Glowing Ice

May 6, 2016
Image of the Week — Glowing Ice
Glowing ice -- winning picture of the EGU photo contest 2016. The image shows a block of ice on the shores of Jökulsárlón, Iceland. [credit: Katharine Cashman (distributed via imaggeo.egu.eu)]

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 o ...[Read More]