UK-OSNAP-Decade: 10 years of observing and understanding the overturning circulation in the subpolar North Atlantic (2014-2024)

There is mounting evidence from measurements and models of the importance of the transports of heat and freshwater by the Subpolar North Atlantic Ocean. They impact on North Atlantic, European and global climate via temperature, precipitation and wind strength, and also on marine ecosystems, hurricanes, even rainfall in the Sahel, the Amazon and parts of the US. The subpolar North Atlantic behaves substantially differently from the subtropical North Atlantic circulation, and their mechanisms and timescales for transport and storage of heat and freshwater are very different. Prior to 2014 the subpolar North Atlantic was inadequately measured, and it is still the case that no ocean general circulation or climate model represents it accurately.

UK-OSNAP-Decade aims to generate new knowledge and understanding of the subpolar North Atlantic to improve predictions of the contribution of the region to climate, by building on the successes of NERC Large Grant UK OSNAP, and as a contribution to the international collaborative project OSNAP (Overturning in the Subpolar North Atlantic Programme). We propose a programme of sustained observation of subpolar North Atlantic circulation and fluxes; a UK contribution to an international trans-basin, full-depth ocean observation array.

The UK-OSNAP-Decade data and results will benefit the National Capability programme CLASS (Climate Linked Atlantic Sector Science) by providing additional information about the warm water pathways in the eastern subpolar North Atlantic, including their heat and salt transport and water mass transformation.

The results from OSNAP will feed into national and international climate assessments including the UK Marine Climate Change Impacts Partnership (MCCIP), the International Council for the Exploration of the Seas (ICES) Annual Report on Ocean Climate, and of course the Intergovernmental Panel for Climate Change (IPCC) Assessment Reports.

The results will underpin EU FP7 programmes including Blue-Action, Atlas and iAtlantic, and contribute to the Global Ocean Observing System (GOOS) as an OceanSites observatory. It is also a contribution to an all-Atlantic observing system.