A 1,100-km project to understand Antarctica's atmospheric water

Antarctica, the South Pole, is Earth’s coldest and most isolated region. A thick layer of ice covers 98% of a virtually untouched wilderness. By virtue of its location, this continent, which is 1.5 times the size of Europe, plays a pivotal role in regulating the world's climate. It is therefore key to our understanding of the environment, and above all climate change.

Berne – an associate professor at EPFL’s School of Architecture, Civil and Environmental Engineering (ENAC) and head of the Environmental Remote Sensing Laboratory – has visited Antarctica several times. He is a specialist in radar meteorology and precipitation microphysics in mountainous and polar environments, and is now working to understand the key processes involved in snowfall in these regions.

On November 5, Berne and the other members of his research team – Valérie Masson-Delmote from the French Alternative Energies and Atomic Energy Commission, Christophe Genthon from the French National Center for Scientific Research, and Thomas Dubos from École Polytechnique in France – were awarded a €14 million Synergy Grant from the European Research Council (ERC) for their AWACA (Atmospheric WAter Cycle over Antarctica) project. This cross-disciplinary project, which is slated to last six years, focuses on the atmospheric component of Antarctica's water cycle. In other words, how snow forms, how it falls, and in what quantity.

By pooling our individual areas of expertise, we hope to better understand this cycle and to use our findings – particularly those obtained from remote sensing – to identify the dominant processes and how they influence snow’s isotopic composition

Extreme conditions

The project's first stage involves a large-scale measurement campaign using a series of instruments positioned between France's Dumont d'Urville station on the Antarctic coast and the French-Italian Concordia Research Station some 1,100 km away on the Antarctic Plateau. The instruments will identify, monitor and record the physics and dynamics of the atmospheric column (clouds and precipitation), the isotopic composition of surface snow, and surface variables (temperature, humidity, wind and wind-blown snow).

"Nothing like this has ever been attempted before. There are huge technological challenges, such as ensuring that our instruments can operate on their own for months on end under extreme weather conditions. On the coast, it's extremely windy with gusts of up to 200 km/h, and the further inland you go, the colder it gets.” At the Concordia station there is no sun for six months of the year, and in winter temperatures can drop to –80°C.

Reassessing ice cores

In the second stage of the project, the team will reassess how ice cores are interpreted; these cores give scientists valuable information about past climate fluctuations. The data collected during AWACA will be completely new and will be compiled over the course of several seasons, far away from inhabited stations. The findings will play an important role in better understanding and predicting climate change. “If this measurement campaign gives us fresh insight into how these processes interact and influence each other, we will be able to reconstruct past climates by taking these previously-overlooked interactions into account. That will help us improve our climate models and reduce the uncertainty associated with this component of the water cycle in future forecasts.”

The level of the world’s oceans is strongly affected by the mass balance of the Antarctic ice sheet – if the ice sheet loses mass through melting, ocean levels rise; on the contrary, if it gains mass through snow accumulation, they fall. Hence the importance of research that will improve our knowledge of the South Pole’s atmospheric conditions and help scientists fine-tune future climate predictions.