The ocean and atmosphere off the Caribbean Islands and South America are the stage of a large international study to address two major climate unknowns: clouds and small-scale ocean dynamics. The EUREC4A-OA project (Improving the representation of small-scale nonlinear ocean-atmosphere interactions in climate models by innovative joint observing and modelling approaches) has gathered teams from four European countries (France, Germany, Italy and Norway), joined by teams from the US and UK, to undertake the largest field observations experiment ever organized, complemented by a range of model simulations of the regional ocean-atmosphere system. The project makes use of numerous innovations in both observing techniques and numerical modelling, with the ambition to reduce uncertainties about the rate and extent of global warming and climate impacts in the future.
Over the last 40 years, climatologists have been grappling with a key parameter on which the extent of future global warming depends: the sensitivity of the climate system to increasing CO2 concentration in the atmosphere. However, they now know that the way in which the ocean and clouds react to global warming lies at the heart of the problem.
In an attempt to get a clearer picture, the EUREC4A–OA project focuses on ocean small-scale dynamics, how these affect the exchanges of properties with the atmosphere and the formation and evolution of cumulus clouds. To initiate and rapidly develop actions to strengthen society's resilience to climate change, numerical predictions and climate projections systems require advances in phenomena understanding and model innovations. The ocean is the main regulator of the world's climate and is especially turbulent in the North Tropical Atlantic Ocean, with many small vortices (less than 100 km in diameter) stirring up water that is warmer than its surroundings. Researchers suspect that these eddies play a fundamental role in the exchange of gases and energy between the ocean and the atmosphere, such as the uptake of CO2 and heat by the ocean. Such turbulent ocean processes and their exchanges with the atmosphere are poorly understood and only summarily represented in climate models.
Researchers in the EUREC4A-OA project study in unprecedented detail phenomena within the boundary layers of the ocean and atmosphere zooming in on spatial scales smaller than 100 km. During the field experiment they deployed simultaneously, in the ocean and atmosphere, more than 100 state-of-the-art instruments and innovative observing platforms. In parallel they set up a vast modelling effort involving 25 different institutions across Europe and the US. These studies will further link with purely airborne observations and novel modelling of clouds physics that represent another major source of uncertainties in weather forecast and climate change projections alike.
Finally, the EUREC4A-OA project has the potential to improve the information gain from satellite remote sensing and to ultimately deliver the design for a more capable fit-for-purpose observing system.
Coordinator: Prof. Sabrina Speich
École normale supérieure - Laboratoire de météorologie dynamique (ENS-LMD), France
Laboratoire de météorologie dynamique, LMD, FRANCE
Laboratoire d'études en géophysique et océanographie spatiales, LEGOS/CNRS, FRANCE
Laboratoire d'océanographie et du climat: expérimentations et approches numériques, LOCEAN/CNRS, FRANCE
Centre national de recherches météorologiques, CNRM/CNRS, FRANCE
Université de Bretagne Occidentale, Laboratoire d'Océanographie Physique et Spatiale, UBO-LOPS, FRANCE
GEOMAR Helmholtz Centre for Ocean Research Kiel, GEOMAR, GERMANY
Max Planck Institute for Meteorology, MPI, GERMANY
Helmholtz-Zentrum Geesthacht, HZG, GERMANY
Università degli Studi di Milano Bicocca, UNIMIB, ITALY
Centro Internazionale In Monitoraggio Ambientale, CIMA, ITALY
Nansen Environmental and Remote Sensing Center, NERSC, NORWAY
University of Bergen, UIB, NORWAY