Bilan

Swiss Experiment: an open-air laboratory for sensor networks

At some 2,300 metres above sea level, on a field several hours’ walk from the town of La Fouly in the canton of Valais, there is a somewhat surprising sight: a dozen metal structures clash with the splendid scenery that stretches along the foot of the Grand Saint Bernard pass. In fact these tripods, flanked by antennas and fibre optics, made the Val Ferret their new habitat more than two years ago. And if their strange shapes are somewhat upsetting, inquisitive walkers just have to approach them to read an inscription revealing their true nature and asking visitors not to disturb them.

These facilities are working hard. In wind, rain, snow or sun, 24/7, they consistently capture, record and transmit all information they have on the some 25 square metres on which they operate. Their mission? To gather as much local weather data as possible to allow Swiss scientists to predict the impact of climate change on the entire Alpine region. The extensive programme – known simply as the Swiss Experiment – was launched in late 2007 by a prestigious academic consortium comprising the Competence Centre Environment and Sustainability, the two Swiss Federal Institutes of Technology, the National Centre of Competence in Research Mobile Information & Communication Systems, the Institute for Snow and Avalanche Research, the Aquatic Research Institute, the Swiss National Fund for scientific research, and Microsoft.

Extending over nearly 25 square kilometres, the Val Ferret site has become one of Professor Marc Parlange’s key fields of research. Parlange is the Director of the Laboratory of Environmental Fluid Mechanics and Hydrology at the Swiss Federal Institute of Technology of Lausanne, and under the umbrella of Swiss Experiment he runs a specific project called SensorScope.

With a network of stations communicating via radio waves, Marc Parlange tries to unravel the mysteries of the water cycle. “Val Ferret is the epitome of a complex territory in terms of hydrology. Even if some stations are only a hundred metres apart, records show very different results in terms of rainfall and the return of rainwater back to the plains. Soil permeability, evaporation, temperatures... there are so many parameters that it defies the imagination,” explains the scientist.

Val Ferret is not the only region that is under careful observation. The Génépi glacier, the Plaine Morte glacier, the Thur River basin, the Davos area... For experts in environmental science, the Swiss Alps have become an experimental subject. With a complex geology, spanning nearly 1,200 kilometres between the Mediterranean and the Danube, the Alps are the essential link in the hydrological cycle of the Old Continent.

“Sensor networks are essential to the Swiss Experiment project. The new data and the development of new modelling tools will improve forecasts of natural hazards, especially in the mountains,” said Michael Lehning, head of the Research Unit Snow and Permafrost at the Institute for Snow and Avalanche Research. The task, then, is sufficient high-quality data to build reliable and robust models. “The more information we gather, the more likely it is that we will be able to predict or to prevent natural disasters such as landslides or avalanches,” explains Marc Parlange.  Cost-effective new instruments

In this game, it is not enough to multiply the number of data-collecting stations. That is why many research projects have been grafted onto Swiss Experiment, for example to improve the quality of the antennas or the data capture and reporting processes. It is also why the project involves the National Competence Centre Mobile Information Systems and Communications. “The project should provide the experts with completely new instruments that are able to observe environmental phenomena at spatial and temporal resolutions unknown until now – and very cost-effectively,» says Karl Aberer, the centre’s director.

The data collected vary across the Swiss Alps. So each region has its specific sensor system, with the weather stations configurable for particular environments. Besides the traditional measurements of temperature, each sensor network focuses on a particular phenomenon: wind speed and precipitation using a lidar (light detection and range sensing) on the rocky Génépi glacier, soil moisture in Val Ferret... Equipped with solar panels, the mini-stations are autonomous and do not require major maintenance or significant human presence. The Institute for Snow and Avalanche Research uses the infrastructure to calculate snow depth and to prevent the risk of avalanche.

These light and easy-to-deploy networks of sensors complement traditional data collections already made by Swiss scientists such as those from the Global Atmosphere Watch of the Geneva-based World Meteorological Organization, or data from the Jungfraujoch station provided by teams of two Swiss Institutes of Technology.

Will Swiss Experiment deliver the expected predictive models? And if so, when? Marc Parlange answers: “We have the tools but it is an ongoing process. Science is built over time. It is by gradually refining our research results that we will achieve our goals.” In the meantime, a new field research project will be led by a team of EPFL near Zinal. It will use a new type of sensor to track the transport of sediments in a tributary of the Rhone river.

 

 

 

 

En français dans le texte

Un laboratoire à ciel ouvert

Château d’eau de l’Europe, les Alpes deviennent le terrain de jeu des scientifiques, en fournissant à ces derniers de précieuses données sur l’impact des changements climatiques.

Lancé  fin 2007, le programme «Swiss Experiment» rassemble un consortium académique prestigieux réunissant le Centre de compétence «Environnement et durabilité», les deux Ecoles polytechniques fédérales, le Pôle de recherche national MICS, l’Institut fédéral pour l’étude de la neige et des avalanches à Davos (WSL) et celui de recherche sur l’eau (EAWAG), le Fonds national suisse de la recherche scientifique, ainsi que Microsoft. Ils développent de nouveaux réseaux de capteurs autonomes comme ceux du projet Sensorscope du Laboratoire de mécanique des fluides de l’environnement de l’EPFL et à partir de données environnementales précises élaborent de nouveaux modèles pour améliorer les prévisions des risques naturels, en particulier en montagne.

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