EGU Guest blogger

Image of the Week – Super-cool colours of icebergs

Lettie Roach March 30, 2018

Fig.1: Clear blue marine ice visible on an upturned iceberg [Credit: Stephen Warren].

It is Easter weekend! And as we do not want you to forget about our beloved cryosphere, we provide you with a picture nearly as colourful as the Easter eggs: very blue icebergs! What makes them so special? This is what this Image of the Week is about… What are icebergs made of? Icebergs are chunks of ice which break off from land ice, such as glaciers or ice sheets (as you’ll know if you rem ...[Read More]

Image of the Week – Geothermal heat flux in Antarctica: do we really know anything?

Brice Van Liefferinge March 23, 2018

Geothermal heat flux is the major unknown when we evaluate the temperature and the presence/absence of water at the bed of the Antarctic Ice Sheet. This information is crucial for the Beyond Epica Oldest Ice project, which aims to find a continuous ice core spanning 1.5 million years (see this previous post). A lot of work has been done* to determine geothermal heat flux under the entire Antarctic ...[Read More]

Image of the Week – Broccoli on Kilimanjaro!

Johanna Kerch March 16, 2018

Figure 1: “Broccoli” bubbles in ice from Kilimanjaro seen in a close-up Photograph. The bubbles look like they are about to explode in the ice. In between the “Broccoli” bubbles are bubbles that look like little disks or bowls, all flattened along the same plane within an volume which is around one ice grain. Ripples in the background originate from the band saw used to cut this ice. The ice slab is approx. 1 cm thick and microtome-polished on the surface [Credit: Johanna Kerch]

On the plateau of Kilimanjaro, Tanzania, the remnants of a glacier can be found and the ice from that glacier contains a rather interesting feature – Broccoli! Not the vegetable, but bubbles that look a lot like it. Our Image of the Week shows some of these strange “Broccoli Bubbles”. Read on to find out more about where these were found and how we can see them. There is not much ice left on the m ...[Read More]

Image of the Week – The colors of sea ice

Polona Itkin March 9, 2018

Thin sections of sea ice photographed under polarized light. Individual ice crystals are shown by different colors. The color is random – it does not tell us anything specific about the crystals. Examples of granular ice, with smaller crystals in the top parts of the ice samples, are shown in the top rows. Columnar ice, with long layered ice crystals, can be seen in the bottom rows. Several pictures with columnar ice have air bubbles, for example all pictures in the left column and the center right picture [Credit: Polona Itkin and Anja Rösel, Norwegian Polar Institute].

The Oscars 2018 might be over, but we have something for you that is just as cool or even cooler (often cooler than -20°C)! Our Image of the Week shows thin sections of sea ice photographed under polarized light, highlighting individual ice crystals in different colors, and is taken from a short video that we made. Read more about what this picture shows and watch the movie about how we got these ...[Read More]

Image of the Week – A Hole-y Occurrence, the reappearance of the Weddell Polynya

Rebecca Frew March 2, 2018

Fig. 1: The Weddell polynya as seen in the 7th September 2017. The size is around 2500 km². Black areas are sea-ice free (open water) [Credit: NASA].

REMARK: If you’ve enjoyed reading this post, please make sure you’ve voted for it in EGU blog competition (2nd choice in the list)! During both the austral winters of 2016 and 2017, a famous feature of the Antarctic sea-ice cover was observed once again, 40 years after its first observed occurrence: the Weddell Polynya! The sea-ice cover exhibited a huge hole (of around 2600 km2 up to ...[Read More]

Image of the Week – The world in a grain of cryoconite

Arwyn Edwards February 23, 2018

Microbes growing on glaciers are recognized for their importance in accelerating glacier melting by darkening their surface and for maintaining biogeochemical cycles in Earth’s largest freshwater ecosystem. However, the microbial biodiversity of glaciers remains mysterious. Today, new DNA sequencing techniques are helping to reveal glaciers as icy hotspots of biodiversity. To see a world in a grai ...[Read More]

Image of the week – Skiing, a myth for our grandchildren?

Marie Cavitte February 16, 2018

Skiing resorts might look very different in a few decades... [Credit: M. Cavitte]

Ski or water ski? Carnival season is typically when many drive straight to the mountains to indulge in their favorite winter sport. However, by the end of the century, models seem to predict a very different future for Carnival, with a drastic reduction in the number of snow days we get per year. This could render winter skiing something of the past, a bedtime story we tell our grandchildren at ni ...[Read More]

Image of the Week – The Gap, the Bridge, and the Game-changer

Thomas Lavergne February 9, 2018

The Gap, the Bridge, and the Game-changer are three series of satellites. They carry instruments that measure the microwave radiation emitted by the Earth (called passive microwave instruments), while flying 800 km above our heads at 7,5 km/s. Since the late 1970s, most sea ice properties (concentration, extent, area, velocity, age and more!) have been measured with such passive microwave instrume ...[Read More]

Image of the Week – Microbes have a crush on glacier erosion

Martyn Tranter January 26, 2018

This aerial image shows that Midtre Lovénbreen has shaped its catchment via erosion over thousands of years. [Credit: Andy Hodson]

Glacier erosion happens at the interface between ice and the ground beneath. Rocks are ground down to dust and landscapes shaped by the flowing ice. While these might be hotspots for erosion, the dark and nutrient-poor sites are unlikely environments for biological activity. However, experiments suggest there may be novel sources of energy powering subglacial microbial life… Where there is water, ...[Read More]

Image of the Week – Ice caps on Mars?!

Violaine Coulon January 19, 2018

Much like our Planet Earth, Mars has polar ice caps too, one for each pole: the Martian North Polar Ice Cap (shown on our image of the week) and the Southern Polar Ice Cap. Yet, their composition and structure reveals these ice caps are quite different from those of Planet Earth… Mars refresher As a refresher, here are some Mars facts: Mars is the 4th planet from the sun. Its equatorial dia ...[Read More]