Cryospheric Sciences

Cryo-Adventures – Hunting snow algae in the Alps

Biagio Di Mauro October 8, 2021

Figure 1. Researchers and students measuring snow optical properties during a snow algae bloom in the beautiful landscape of the Brenta Dolomites (Rhaetian Alps). [Credit: Cristian Ferrari]

We are used to think of algae as marine or lacustrine organisms, but they are actually able to thrive also on the cryosphere. In a previous post, we learnt how snow algae live and reproduce on snow. Now we will explore how and why scientists study snow algae, and how social media can be used for identifying new study areas. Snow algae in the Alps Snow algae in the Alps have been overlooked or conf ...[Read More]

Questions from space: what is snow and what is ice on the Greenland ice sheet?

Adrien Wehrlé July 2, 2021

Fig.1: Extremely dark bare ice at QAS_U automatic weather station on August 4, 2014. Credits: Jason E. Box

We usually think of a glacier as a white, clean surface. Well, this is only an idealized vision because in reality glaciers are far from immaculate, they can be colored! And this is extremely important since colored (dirty) ice absorbs more solar radiation than clean ice, accelerating melt. One of the places on Earth where it is fundamental to understand these processes is Greenland, where ice is ...[Read More]

Time To Reflect

Samuel Cook December 11, 2020

Albedo or albedon’t? One possible solution to global warming is to turn everything white to increase the planet’s albedo, i.e. how reflective it is (see, for example, this website). A higher albedo would be one way to reduce global warming, by reducing the amount of incoming shortwave solar radiation absorbed by the planet’s surface, which is then re-emitted as longwave radiation that ...[Read More]

Image of the Week – What darkens snow and ice?

Biagio Di Mauro September 18, 2020

“Be thou as chaste as ice, as pure as snow”. Hamlet, Act 3 Scene 1 (W. Shakespeare) Snow and ice are not always as pristine as one may think. If you have ever walked on a glacier or on a snowfield during summer, you might have already noticed that. In fact, both snow and ice are often darkened by impurities. In this blog post, you will learn about the main processes leading to ice and snow darkeni ...[Read More]

Climate Change & Cryosphere – Summer 2019: The year that the Arctic was sunburned

Jenny Turton September 20, 2019

June, July and August 2019 saw extensive heat waves across Europe, with air temperatures reaching above 40°C in many countries. In response, record breaking ice melt was observed in Greenland and wildfires in Siberia, Alaska, Arctic Canada and Greenland occurred. A particularly dry and warm summer was responsible for hemisphere-wide changes to the cryosphere. In this week’s post, we will review so ...[Read More]

Image of the Week – On thin [Arctic sea] ice

Chris Horvat October 19, 2018

Perhaps the most enduring and important signal of a warming climate has been that the minimum Arctic sea ice extent, occurring each year in September, has declined precipitously. Over the last 40 years, most of the Arctic sea ice has thus been transformed to first-year ice that freezes in the winter and melts in the summer. Concern about sea ice extent and area is valid: since sea ice i ...[Read More]

Image of the Week — Climate change and disappearing ice

Sophie Berger November 10, 2017

The first week of the Climate Change summit in Bonn (COP 23 for those in the know) has been marked by Syria’s decision to sign the Paris Accord, the international agreement that aims at tackling climate change. This decision means that the United States would become the only country outside the agreement if it were to complete the withdrawal process vowed by President Trump. In this context ...[Read More]

Image of the Week – Bioalbedo: algae darken the Greenland Ice Sheet

Joseph Cook September 8, 2017

Fig 1: This aerial image shows the surprisingly dark grey-brown colour of the Greenland Ice Sheet surface, around the ‘Black and Bloom’ camp. [Credit: 'Black and Bloom']

Most of the energy that drives glacier melting comes directly from sunlight, with the amount of melting critically dependent on the amount of solar energy absorbed compared to that reflected back into the atmosphere. The amount of solar energy that is reflected by a surface without being absorbed is called the albedo. A low albedo surface absorbs more of the energy that hits it compared to a high ...[Read More]

Image of the Week – Fifty shades of snow

Clara Burgard July 21, 2017

Fig. 1: Green snow [Credit: NASA's Earth Observatory]

When I think of snow, I tend to either think about the bright white ski slopes in the mountains or the large white areas in the Arctic. However, natural phenomena can lead to colorful snow. Our Image of the Week shows snow can be green! Snow can also turn orange, pinkish, grey and even yellow… But where do these different shades of snow come from? White The most common color of snow is white (see ...[Read More]

Black Carbon: the dark side of warming in the Arctic

Patrik Winiger November 2, 2016

Greenland in summer: ice is covered by dark particles -- Black Carbon -- which amplify melting. [Credit : NASA ICE distributed via flickr]

When it comes to global warming, greenhouse gases – and more specifically CO2 – are the most often pointed out. Fewer people know however that tiny atmospheric particles called ‘black carbon’ also contribute to the current warming. This post presents a paper my colleague and I recently published in nature communications. Our study sheds more light into the chemical make-up of black car ...[Read More]