satellite observations

An exceptional year: What’s up with Antarctic sea ice?

David Docquier November 17, 2023

Figure 1: Daily cycle of the Antarctic sea-ice extent (in million km²) for each 10-year period between 1979 and 2018 (10-year averages) and for 3 separate years, including 2023 (red curve). Snapshot of 12 November 2023 [Credit: NASA., Comiso et al., “Current State of Sea Ice Cover”, see: https://earth.gsfc.nasa.gov/cryo/data/current-state-sea-ice-cover].

In our blog, we have written a lot about Arctic sea ice (see this post, this post and this post for recent examples). Much less has been written about Antarctic sea ice, i.e. its southern counterpart. That is not surprising as Arctic sea ice has experienced major losses since the late 1970s (beginning of satellite observations), while not much had happened to Antarctic sea ice (despite a small exp ...[Read More]

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]

For Dummies: Radar altimetry for measuring ice sheet elevation changes

Inès Otosaka March 3, 2023

Greenland and Antarctica surface elevation changes from CryoSat-2. Credit: ESA, Inès Otosaka.

Does measuring the surface of the ice sheets provide more than superficial knowledge of their current status? Read further to find out why the answer is definitely yes! Measuring surface elevation changes actually tells us where Greenland and Antarctica are thinning or thickening and how much they contribute to sea level rise. Scientists have been doing this for the past three decades, so keep on ...[Read More]

Mapping sea ice from space

Andrea Schneider, Thomas Kræmer, Alistair Everett, Johannes Lohse, Nick Hughes and Tom Rune Lauknes September 10, 2021

Figure 1. The thinning and retreating of sea ice have led to increased human activity in Arctic waters. Hence, marine traffic and activities such as fishing, shipping, oil and mineral exploitation are expected to increase in the future. To handle navigation in ice-covered waters, vessel crews need appropriate planning support. [Credit: Alex Perz/Unsplash]

Reduced and thinner sea ice makes Arctic waters increasingly appealing for shipping, fishing, tourism, and mineral exploration. However, with increased accessibility and more dynamic ice conditions comes a greater risk for ship crews to encounter sea ice and icebergs outside of their usual seasonal limits. To help them navigate, timely and reliable sea ice information is key. Have you wondered how ...[Read More]

Did you know… that you can read the edge of Greenland’s ice as an open book?

Joe MacGregor November 20, 2020

Layering of ice along the northern margin of the Greenland Ice Sheet, Daugaard-Jensen Land. Figure credit: John Sonntag.

Scientists struggle to get ice samples from the depths of glaciers where fundamental pieces of information about the climate of Earth are stored. But in many places around the periphery of the Greenland Ice Sheet, you don’t need to drill a deep ice core to obtain ancient ice, you can simply walk across the ice sheet’s margin and look at the layered ice surface. There you can read the ice as though ...[Read More]

Does debris cover offset glacier retreat in the Greater Caucasus?

Levan Tielidze April 3, 2020

Figure 1: Supra-glacial debris cover (SDC) change on the Elbrus Massif from 1986 to 2014. A SPOT-7 image is used as the background. Blue shows retreat of clean-ice parts. Clean ice in 1986 consists of the clean ice in 2014 (grey, transparent) plus clean-ice area that retreated between 1986 and 2014 (dark blue). Credit: Tielidze et al., 2020

In this week’s blog, Levan Tielidze tells us about supra-glacial debris cover change for the Greater Caucasus. His recent study indicates more than a doubling in the area of supra-glacial debris cover for the Elbrus Massif‘s glaciers from 1986 to 2014, the largest glacierized massif in the whole region. Glaciers on the western slope of the Elbrus Massif are affected by avalanches and thus ar ...[Read More]

Image of the Week – Ice-Spy: the launch of ICESat-2

Liam Taylor December 7, 2018

On September 15th, 2018, at 18:02 local time, NASA launched its newest satellite – the second generation Ice, Cloud and land Elevation Satellite (ICESat-2). ICESat-2 only contains one instrument – a space laser that fires 10,000 pulses per second to Earth to measure elevation. Its primary purpose is for monitoring the ever changing cryosphere, so naturally there are plenty of ice enthusiasts ...[Read More]

Image of the Week — Orange is the new white

Simon Gascoin, Marie Dumont and Ghislain Picard June 15, 2018

On 22 March 2018, large amounts of Saharan dust were blown off the Libyan coast to be further deposited in the Mediterranean, turning the usually white snow-capped Mountains of Turkey, Romania and even Caucasus into Martian landscapes. As many people were struck by this peculiar color of the snow, they started documenting this event on social media using the “#orangesnow hashtag”. Instagram and t ...[Read More]

Image of the Week – Of comparing oranges and apples in the sea-ice context

David Docquier October 27, 2017

Fig. 1: Model-to-observation comparison of sea-ice variables might best be conducted at a middle-ground "location" (along the x axis) somewhere in between what the models compute (left) and what satellites observe at the top of the atmosphere (right). Obs Oper = Observation Operators, SIC = sea-ice concentration, ISF = ice surface fraction [Credit: Lavergne, 2017 ].

In the last fifty years, models and observations have enabled us to better understand sea-ice processes. On the one hand, global climate models have been developed, accounting for the sea-ice component in the climate system. On the other hand, satellite instruments have been developed to monitor the “real” sea-ice evolution. These satellite observations are often used to evaluate climate models. H ...[Read More]

Image of the Week: Petermann Glacier

Laurence Dyke September 29, 2017

Our image of the week shows the area around the calving front of Petermann Glacier through the spring, summer, and autumn of 2016. Petermann Glacier, in northern Greenland, is one of the largest glaciers of the Greenland Ice Sheet. It terminates in the huge Petermann Fjord, more than 10 km wide, surrounded by 1000 m cliffs and plunging to more than 1100 m below sea level at its deepest point. In 2 ...[Read More]