Ice-Ocean interaction

It’s not you, it’s me(lange): ice shelf break-up triggered by mélange and sea-ice loss

Jenny Arthur May 21, 2021

Fig. 1. Mélange (a mixture of calved icebergs, sea ice and material) in Porpoise Bay, East Antarctica, located ~100 km east of Voyeykov Ice Shelf [Credit: NASA Operation IceBridge].

Between March and May 2007, a total of ~2,445 km2 (equivalent to over 17 football pitches) of ice mélange (a mixture of sea-ice types, icebergs and snow) and part of Voyeykov Ice Shelf in East Antarctica rapidly broke up. Observations of the timing and triggers of such events are relatively rare in East Antarctica, compared to ice shelves on the Antarctic Peninsula. Recent work highlights the impo ...[Read More]

Image of the Week – Icebergs increase heat flux to glacier

Ben Davison January 15, 2021

Iceberg in Sermilik Fjord. Figure credit: Donald Slater.

Icebergs are ubiquitous in Greenland’s fjords, melting and releasing freshwater as they float towards the open ocean. The amount of freshwater released from these icebergs can be vast – the equivalent of around 50,000 Olympic swimming pools per day in some fjords. New research reveals that this freshwater causes fjord currents to speed-up, which can actually increase the amount of heat delivered t ...[Read More]

Did you know? – Ocean bathymetry can control Antarctic mass loss!

Sainan Sun January 10, 2020

Ice shelves (the floating parts of the Antarctic ice sheet) play a fundamental role in the stability of the Antarctic ice sheet (see this post) and, therefore, its contribution to global sea-level rise. They lose mass primarily through melting at their bases, which are in contact with the ocean. This thins them and makes them more vulnerable, reducing their stabilising potential and causing more i ...[Read More]

Image of the Week – The GReenland OCEan-ice interaction project (GROCE): teamwork to predict a glacier’s future

Jenny Turton May 31, 2019

The GROCE project, funded by the German Ministry for Education and Research (BMBF), takes an Earth-System approach to understand what processes are at play for the 79°N glacier (also known as Nioghalvfjerdsfjorden), in northeast Greenland. 79°N is a marine-terminating glacier, meaning it has a floating ice tongue (like an ice shelf) and feeds into the ocean. Approximately 8% of all the ice contain ...[Read More]

Image of the Week — Cavity leads to complexity

David Docquier April 19, 2019

A 10km-long, 4-km-wide and 350m-high cavity has recently been discovered under one of the fastest-flowing glaciers in Antarctica using different airborne and satellite techniques (see this press release and this study). This enormous cavity previously contained 14 billion tons of ice and formed between 2011 and 2016. This indicates that the bottom of the big glaciers on Earth can melt faster tha ...[Read More]

Image of the Week – (Un)boxing the melting under the ice shelves

Ronja Reese November 30, 2018

Figure 1: Melting underneath Antarctic ice shelves as modelled with the Potsdam Ice-shelf Cavity mOdel (PICO) for present-day ice geometries and ocean conditions. Extending a simple ocean box model approach (Olbers and Hellmer, 2010), it efficiently calculates the wide range of melting in Antarctica [Credit: adapted from Fig. 5 of Reese et al. (2018)]

The Antarctic ice sheet stores a large amount of water that could potentially add to sea level rise in a warming world (see this post and this post). It is currently losing ice, and the ice loss has been accelerating in the past decades. All this is linked to the melting of ice – not at the surface but at the base, underneath the so-called ice shelves which form the continuation of the Antarctic i ...[Read More]

Image of the Week — Think ‘tank’: oceanography in a rotating pool

Céline Heuzé October 20, 2017

To study how the ocean behaves in the glacial fjords of Antarctica and Greenland, we normally have to go there on big icebreaker campaigns. Or we rely on modelling results, especially so to determine what happens when the wind or ocean properties change. But there is also a third option that we tend to forget about: we can recreate the ocean in a lab. This is exactly what our Bergen-Gothenburg tea ...[Read More]

Image of The Week – The Pulsating Ice Sheet!

Emma C. Smith March 3, 2017

Figure 1: (a) Ice sheet at its most advanced state, the terminus is grounded 300 m beneath sea level (b) An ocean-warming event triggers retreat (c) Retreat is amplified by enhanced calving as the ice sheet retreats into deeper water (d) After the collapse, the ice sheet is in its most retreated position. Isostatic adjustment uplifts the bed (and sill) which will allow the ice sheet to advance again. Insets show a close-up around the sill. [Credit: Bassis et al., 2017]

During the last glacial period (~110,000-12,500 years ago) the Laurentide Ice Sheet (North America) experienced rapid, episodic, mass loss events – known as Heinrich events. These events are particularly curious as they occurred during the colder portions of the last glacial period, when we would intuitively expect large-scale mass loss during warmer times. In order to understand mass loss m ...[Read More]

Image of the Week — The ice blue eye of the Arctic

Céline Heuzé February 24, 2017

Ice floe with a melt pond (light blue patch), observed in Nares Strait , in August 2015 from I/B Oden [Credit: C. Heuzé]

“Positive feedback” is a term that regularly pops up when talking about climate change. It does not mean good news, but rather that climate change causes a phenomenon which it turns exacerbates climate change. The image of this week shows a beautiful melt pond in the Arctic sea ice, which is an example of such positive feedback. What is a melt pond? The Arctic sea ice is typically non-smooth, and ...[Read More]

Image of The Week – Plumes of water melting Greenland’s tidewater glaciers

Donald Slater October 28, 2016

Loss of ice from The Greenland Ice Sheet currently contributes approximately 1 mm/year to global sea level (Enderlin et al., 2014). The most rapidly changing and fastest flowing parts of the ice sheet are tidewater glaciers, which transport ice from the interior of the ice sheet directly into the ocean. In order to better predict how Greenland will contribute to future sea level we need to know mo ...[Read More]