- 1Utrecht University, Institute for Marine and Atmospheric research Utrecht (IMAU), Physics, Netherlands
- 2Centre for Complex Systems Studies, Utrecht University, Utrecht, the Netherlands.
Simple box models of the Atlantic Meridional Overturning Circulation (AMOC) often rely on ad-hoc scaling laws that link AMOC strength to the meridional density gradient. In contrast, Global Climate Models (GCMs) provide more comprehensive simulations but demand substantial computational resources. To evaluate the validity of these scaling laws, we develop a simplified AMOC model that represents the circulation as a geostrophically balanced flow confined to the western boundary of the Atlantic basin. Basin-wide pressure gradients are driven by mixing along continental boundaries and wind-driven upwelling in the Southern Ocean. We explore the limiting cases of quasi-adiabatic and diffusive overturning circulations, deriving corresponding scaling laws for AMOC strength. Given the critical influence of these scaling laws on AMOC stability, we examine how stability depends on the dominant driving mechanism—either diffusive mixing or adiabatic upwelling. This analysis aims to identify GCM biases that could significantly affect AMOC stability and must be addressed to accurately assess the risk of an AMOC collapse in the coming century.
How to cite: Vanderborght, E. and Dijkstra, H.: A Mechanical Model for the Inter-Hemispheric Overturning Circulation, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16235, https://doi.org/10.5194/egusphere-egu25-16235, 2025.