A team of ULB and UCLouvain researchers just returned from a nearly two-month mission in Antarctica. They studied the mass balance of the Antarctic ice sheet by analysing snow accumulation. Hugues Goosse, the project’s coordinator and a part-time professor at the UCLouvain Earth and Life Institute, gives us his first impressions and observations.
In late 2018, Hugues Goosse, the coordinator of the MASS2ANT project and a part-time professor at the UCLouvain Earth and Life Institute, explained to Science Today why he was headed to Antarctica, a white paradise, at least for studying climate evolution. Now he’s back after spending a rich, scientific adventure in the middle of nowhere for more than a month on the Southern Continent.
Studying three parameters
On 1 December 2018, he flew to Cape Town, accompanied by an interuniversity team (UCLouvain, ULB and University of Colorado at Boulder). Their goal was threefold: to collect snow from several places to study its accumulation, to drill an ice core as deeply as possible to analyse each layer, and measure ice movement. These three parameters provided clues as to how the climate has evolved in recent decades, and how it will evolve in the near future. Indeed, any climate change in Antarctica impacts the rest of the world.
Where no one has ever set foot
It took a long time to reach the base camp: almost two weeks (including four days waiting in a Russian base for better weather) and a week to return to the flat country. The team stayed four weeks, outfitted with one container of equipment, another container with kitchen, bathroom and toilet, a large tent to cover the drilling site in case of bad weather, and small tents in which to sleep. The camp was set up on top of a small hill of ice, so that it flowed in the same way in all directions and that this flow disrupts as little as possible the interpretation of the ice core. ‘The first days,’ Prof. Goosse says, ‘we knew what we had to do, we focused on not wasting precious time. It was only gradually that we realised we were in a unique environment, that the closest neighbour was 80 kilometres away and that no one had ever set foot where we were. Everything was vast and empty. There was no life. So the experience was all the more intense.’ A guide and mechanic accompanied them to warn of dangerous places and make repairs.
The first few days, everything started slowly: the team began drilling, took samples of snow and planted bamboo sticks that will help measure ice movement next year. ‘The main obstacles we encountered were logistical,’ Prof. Goosse says, ‘it only takes one malfunctioning part to get stuck. But the ingenuity of the mechanic and the team amazed me.’ The other unexpected obstacle was that it was too warm to drill. ‘You can’t let the ice cores heat up, otherwise chemical reactions destabilise the measurements. But in the drill tent, it was too hot. So we decided to drill at night, when temperatures were under -8.’ Even though the sun shone 24 hours a day, night-time temperatures remained near -10 and daytime around 0.
A 260.1-meter core
At the end of the four-week mission, the team returned to Belgium with several samples and countless data. They drilled more than 200 meters deep to harvest an ice core of 260.1 meters, 50 meters deeper than last year. ‘The other good news is that the ice is of good quality, thanks to new techniques.’ It will take a little longer before ULB analyses the core, because it’s still in a freezer in Antarctica and will be sent by boat to Antwerp in the coming months. The team also noted that the ice moved one meter compared to its location last year. Finally, researchers were able to measure the properties of surface snow and its layers, and analyse them on the spot.
A regional or global phenomenon?
Having just returned, Prof. Goosse observes, ‘It’s still too early to draw conclusions.’ The team knows that there are various temperature profiles, that sometimes there is melting on the surface, and that overall there is a great deal of spatial variability. These variations sometimes depend on a topographic difference of about ten meters. Now the question is: Are these data representative of a phenomenon on a larger scale? To date, the simplest hypothesis is that locally, the measures taken are modified by winds and vary according to position relative to them. But this hypothesis is only local. Prof. Goosse will try to find links between local changes and those on a larger scale.
In the coming months, he will compare models to reality and thus analyse processes (role of wind, temperature, ocean air mass input and its exchanges with the continent, etc.). He will try to model the evolution of the temperature inside the boreholes. Meanwhile, other team members will work on other parameters (ice movement, core analysis, comparison of snow samples). The objective is to gradually recreate the regional climate, with the first results expected in June 2019.
During the mission, the team not only spent New Year’s Eve but also Christmas together: for dessert after a well-deserved fondue, team members had drinks chilled by ice drilling debris. Below 50 meters, bubbles are trapped as snow turns into ice under pressure. When these pieces of ice melt, a faint sound is heard. A pleasant noise to listen to!
A glance at Hugues Goosse's bio
Hugues Goosse is a professor at UCLouvain where he teaches climatology and related disciplines and is research director at the Belgian Scientific Research Fund (F.R.S - FNRS). His research focuses on the development of climate models, the comparison of model results with different types of observations, and the application of these models to past and future climate change. He studies both natural variations and climate change induced by human activities. More specifically, his recent work focuses on the interactions between sea ice and the ocean in the Southern Ocean, climate change over recent millennia, and data assimilation methods in paleoclimatology.