UK OSNAP 4

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, 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 shortcomings in its representation in ocean-only and coupled climate models lead to low confidence in projections of how it will evolve over the 21st century.

UK-OSNAP 4 is the next stage in a 10-year long UK programme to generate new knowledge and understanding of the subpolar North Atlantic to improve predictions of the contribution of the region to climate 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.