Are Atlantic meridional overturning circulation mean state and variability consistent in depth- and density-space? How does it influence mean heat transport?

Goal

• Understand Atlantic meridional overturning circulation variability in the past three decades and its impact on Atlantic heat transport in ECCO V4r5 & V4r4.

Resources Used

• ECCO V4r5: temperature, density, volume flux, velocity, and grid products.
• Tools: ecco_v4_py, ecco_access, OSS, P-Cluster, EMU Tools.
• ESS25 Tutorials, ecco_v4_py Tutorials.

Highlights

• Python routine to compute the density-space AMOC.
• Comparison of depth-space and density-space AMOC mean state and variability.
• Subpolar AMOC signal is only captured in density space.
• Both frameworks show meridional incoherence in interannual AMOC variability.
• Diagnosis of the sharp 2010 drop in MHT at 30°N using EMU Attribution and Adjoint tools.
• Anomalous weak subtropical easterlies are responsible! Likely linked with negative NAO phase.