PI: Henryk Dobslaw (GFZ), Michael Schindelegger (UBN)

Short description

In the wake of improvements to the non-tidal background model AOD1B during the first phase of NEROGRAV, IP2 will focus on the detectability of subtle ocean bottom pressure (OBP) signatures of the meridional overturning circulation in the North Atlantic. Specifically, we will (1) elucidate the nature of the broad-scale OBP signals governing the Landerer et al. (2015) GRACE estimate for Lower North Atlantic Deep Water (Lower NADW, depths ~3–5 km) transport anomalies, using adjoint gradient decomposition in a general circulation model, and (2) map the OBP signatures of the main NADW flow (~1–3 km) on the narrow western continental slope with a dedicated collection of numerical ocean models. These ventures will allow us to analyze newly available gravity field time series from NEROGRAV, and the international science community, for peak NADW transports over the GRACE/GRACE-FO mission periods, and eventually derive threshold/breakthrough requirements for monitoring Atlantic overturning circulation changes with future satellite gravity missions.