Overturning in the Subpolar North Atlantic Program

The Overturning in the Subpolar North Atlantic Program (OSNAP) is an international project designed to study the mechanistic link between water mass transformation at high latitudes and the meridional overturning circulation in the North Atlantic (AMOC[1]) on interannual time scales.

[2] OSNAP intends to fill that gap by providing a continuous record of the trans-basin fluxes of heat, mass and freshwater for a comparison to records of convective activity and water mass transformation at high latitudes in the North Atlantic.

The OSNAP observing system, fully deployed in the summer of 2014, consists of moorings, gliders and RAFOS floats spanning the subpolar North Atlantic from Labrador to Greenland to Scotland.

Geostrophic currents in the basin interior are estimated using temperature and salinity measurements from moorings and gliders.

[3] In conjunction with the RAPID/MOCHA array at 26⁰N, the EU THOR/NACLIM program and other observational elements, OSNAP will provide a comprehensive measure of the three-dimensional AMOC in the North Atlantic and an understanding of what drives its variability.