UK-OSNAP aims to understand the Subpolar Gyre circulation and fluxes using models, data assimilation and theoretical analysis.

The programme aims to understand how ocean heat storage in the Subpolar Gyre varies through a combination of data assimilation and forward model integrations. This will identify how changes in the heat storage in the Subpolar Gyre are controlled by a combination of surface heat flux anomalies and the convergence in ocean heat transport. It also helps to understand how the surface winds and surface buoyancy forcing affect the convergence of heat over the Subpolar Gyre, and explore the connection with the forcing and heat transport at lower latitudes.

The programme will identify the teleconnections between Subpolar Gyre forcing anomalies and the strength and structure both of the Subpolar Gyre and of the Atlantic Meridional Overturning Circulation (AMOC) at lower latitudes. This will involve a combination of adjoint modelling at non-eddying resolution, high-resolution eddy-permitting forward modelling and theoretical analysis. As well as unravelling the contributions of local and remote wind and buoyancy forcing to the Subpolar Gyre, the AMOC and other climatically relevant metrics such as heat transport, this will aid the design of a longer term monitoring system and the attribution of heat content changes.