European contribution to the OneArgo array

The Argo Programme is a major component of both the Global Ocean Observing System (GOOS) and the Global Climate Observing System (GCOS), providing near-real time data for ocean and atmospheric services and high-quality data for climate research. Although originally designed to provide temperature and salinity profiles in the upper 2 km of the ice-free ocean, the array has been expanded into seasonal ice zones. In addition, regional pilot programmes have demonstrated that some Argo floats can now measure biogeochemical parameters to address oceanic uptake of carbon, acidification, and deoxygenation (BioGeoChemical, BGC-Argo) and some floats are also able to make measurements throughout the water column down to 6000 m depth (Deep-Argo). These new BGC-Argo and Deep-Argo Missions, together with the initial Core-Argo Mission form the new global, full-depth and multidisciplinary OneArgo programme (Roemmich et al. 2019). Euro-Argo aims at maintaining ¼ of the global OneArgo array, with a regional perspective focusing on European marginal seas (Mediterranean, Black and Baltic seas) and the European part of the Arctic seas. The Euro-Argo strategy focuses on providing sustained high quality oceanic data to the scientific community for better understanding of the role of the Ocean in the Earth’s climate. Addressing issues of climate change along with expanding floats’ capabilities and coverage are at the centre of the Euro-Argo strategy. Another domain of grand challenges is related to the health of the oceanic ecosystem and its impacts on society. The recent technological advances in biogeochemical instrumentation on Argo floats have greatly improved the ability to address ecosystem monitoring, and gather data in the European marine areas to support climate and biodiversity policies set up by the European Union. Moreover, Argo is a major source of information for operational centres such as the Copernicus Marine and Climate Services and the European Centre for Medium-Range Weather Forecasts (ECMWF) in Europe, for the provision of ocean and weather forecasts and seasonal predictions. Euro-Argo supports the enhancement of monitoring and observing systems at regional scales for model-assimilation and model-validation purposes. In particular, the extensions of Argo into the deep ocean and ecosystem parameters offer new possibilities and will help to constrain and improve the models and resulting products. Within this context, Euro-Argo is currently revising its deployment and coverage strategy for the next decade, taking into consideration specific European needs in terms of in situ ocean observations, while contributing to the global OneArgo new ambitious design. We will present this strategy and provide some highlights on the challenges for the years to come.