Cryospheric Sciences

Recipe to quantify calibration errors in a time-dependent ice sheet model

Beatriz Recinos, Dan Goldberg and James Maddison October 27, 2023

Figure 1: Upper diagram: schematics of baking a pie, representing an idealized 1D Bayesian inverse problem. Lower diagram: schematics of a multi-dimension ice sheet inverse problem solved using FEniCS_ice error propagation framework, created from a compilation of figures from Recinos et al. (2023). FEniCS_ice is designed to solve these problems over a finite element mesh containing (in this study case) more than 100,000 elements. These elements are the vertices, faces, and edges that form our triangular mesh (red map, check out ingredients list below for more information). [Credits: Beatriz Recinos, baking icons from https://www.flaticon.com/].

Ice sheet models are awesome tools that help us learn and predict the fate of ice sheets under human-induced climate change. However, all models have errors. What types of uncertainties exist in an ice sheet model and how can we quantify some of them efficiently? Check out our recipe to quantify one type of uncertainty in sea level rise projections: The model calibration error. Not a numerical mod ...[Read More]

The “Cliffs Notes” on Ice-Cliff Failure

Anna Crawford May 6, 2021

An ice cliff above the ocean adjacent to Thwaites Glacier in West Antarctica. Credits: NASA Public domain, via Wikimedia Commons.

The retreat of large glaciers that drain the Greenland and Antarctic ice sheets could expose immense ice-cliffs at newly-bared calving faces, which are the exposed ends of glaciers where, in these cases, glacier ice meets the ocean. Past a certain height, these ice cliffs will become susceptible to collapsing from high stresses, a process known as structural ice-cliff failure. If a taller ice clif ...[Read More]

Climatic drivers of permafrost mounds in North American peatlands

Richard Fewster September 11, 2020

Figure 1. Palsas (permafrost mounds) at Stordalen Mire, Abisko, Sweden. Photo credit: Graeme Swindles.

Permafrost, or perennially frozen, peatlands are among the world’s largest terrestrial carbon stores and are particularly threatened by warming climates. Understanding how modern climate controls the distribution of permafrost peatlands is crucial for making confident predictions of their past and future extents. What are permafrost peatlands? Peatlands are wetlands that develop where cold, wet co ...[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 – Karthaus Summer School 2017

Dorota Medrzycka October 13, 2017

Glaciologists often undertake fieldwork in remote and difficult to access locations, which perhaps explains why they happily travel to similar locations to attend meetings and workshops. The Karthaus Summer School, which focuses on Ice Sheets and Glaciers in the Climate System, is no exception. The idyllic village of Karthaus, located in the narrow Schnalstal valley in Südtirol (Italy), has been h ...[Read More]

Image of the Week – A high-resolution picture of Greenland’s surface mass balance

Brice Noël April 14, 2017

Fig. 1: Surface mass balance (SMB) of the Greenland ice sheet and peripheral ice caps at 1 km resolution averaged for 1958-2015. The interior of the ice sheet (blue) accumulates mass from snowfall whereas the narrow margins (red) lose mass from runoff of meltwater. Yellow dots locate on-site measurements. At this resolution, the small ice caps and marginal glaciers are accurately resolved [Credit: Brice Noël]. Click here here to enlarge the image.

The Greenland ice sheet – the world’s second largest ice mass – stores about one tenth of the Earth’s freshwater. If totally melted, this would rise global sea level by 7.4 m, affecting low-lying regions worldwide. Since the 1990s, the warmer atmosphere and ocean have increased the melt at the surface of the Greenland ice sheet, accelerating the ice loss through increased runoff of meltwater and i ...[Read More]

Image of The Week – Ice Flows!

Sammie Buzzard March 17, 2017

By changing factors such as snowfall and temperature players can alter the ice flow and make sure that icebergs starts to form just where the penguins want to dive down and catch fish, but get it wrong and there’s a seal waiting! [Credit: Still image from the Ice Flows game]

Portraying ice sheets and shelves to the general public can be tricky. They are in remote locations, meaning the majority of people will never have seen them. They also change over timescales that are often hard to represent without showing dramatic images of more unusual events such as the collapse of the Larsen B Ice Shelf. However, an app launched in the summer at the SCAR (Scientific Committe ...[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]

Katabatic winds – A load of hot (or cold) air?

Thomas Shaw January 25, 2017

Figure 1: A schematic of the potential wind flow and interplay of local effects on Tsanteleina Glacier in the Italian Alps. The diagram represents wind modelling, measured data and observations from the field. (1) The interactions of down-glacier katabatic winds (blue) and up-valley winds/local heat sources (red); (2) the potential heat emitted from the warm valley surroundings (pink) and; (3) localised surface depressions representing glacier 'cold spots' during calm, high pressure conditions. Arrows correspond to synoptic westerlies (purple), southerly airflow (orange), katabatic winds (blue) and valley winds (red) [Credit: T Shaw, unpublished] - Click here for a larger version.

It might seem obvious that a warming world will lead to a reduction in glacial ice cover, but predicting the response of glaciers to climatic change is no simple task (even within the short term). One way to approach this problem is to come up with relationships which describe how glaciers interact with the world around them, for example, how the ice interacts with the air above it. Our post today ...[Read More]

Ice-Hot News : The “Oldest Ice” quest has begun

Oldest Ice PhD Students November 14, 2016

There is million-year old ice somewhere deep under the surface of the Antarctic ice sheet! [Credit: Brice Van Liefferinge]

This is it! The new European horizon 2020 project on Oldest Ice has been launched and the teams are already heading out to the field, but what does “Old Ice” really mean? Where can we find it and why should we even care? This is what we (Marie, Olivier and Brice) will try to explain somewhat. Why do we care about old ice, ice cores and past climate? Unravelling past climate and how it responded to ...[Read More]