OneArgo : Evolving and extending Argo’s missions and data delivery. Achievements, status and outlook

In an era of unprecedented changes to the ocean state and its ecosystems, and the ocean’s significant role in a changing climate, there is an urgent need for global, transparent and multidisciplinary observations of the oceans. The pioneering Argo array has demonstrated the feasibility of using mass autonomy to efficiently monitor the largescale structure of the upper 2km of the ocean in real-time, with all its data freely shared with all nations. Argo data now underpin many ocean, climate and storm forecasting services, saving lives and properties. Climate assessments rely on Argo data to track ocean warming, and thus the Earth’s energy imbalance, the process driving climate warming. In addition, researchers all over the world use Argo data to make new discoveries about the ocean without requiring access to research vessels. Materials generated by Argo raise public awareness and assist educators to use the data to teach students about the ocean and its role in our climate system.

At the OceanObs19 Conference, a new and more ambitious design for Argo was endorsed. This OneArgo design involves the extension of Argo to full ocean depth, a suite of sensors to measure BioGeoChemical (BGC) parameters and the routine coverage of the fast-changing polar oceans. The global Argo community is an international collaboration of 25 partners, which has established an infrastructure to sustain ocean observations and share the data. Through pilot arrays and with continued technical breakthroughs, the capability to implement and operate the new OneArgo array has been demonstrated. This array will enable the global community to track the oceans in new and unprecedented ways, providing a synergistic subsurface extension to several key space-based Earth Observation missions. Specifically, OneArgo will enable biogeochemical and ecosystem forecasting and new long-term climate predictions for which the deep ocean is a key component. In addition, OneArgo will help track carbon fluxes in the oceans, investigate how plankton communities vary and are responding to environmental changes, and where and how the oceans are losing oxygen. OneArgo will enable a much more accurate understanding of the drivers of sea level change, both at global and regional scales. It will drive forward another revolution in our understanding of the poorly measured green, polar and deep oceans. We propose to present the opportunities OneArgo will enable for all nations, and the challenges we face in implementing this new major upgrade in global ocean observing capability.