EGU21-6321, updated on 04 Mar 2021
https://doi.org/10.5194/egusphere-egu21-6321
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Revealing mechanisms of change in the Atlantic Meridional Overturning Circulation under global heating

Maike Sonnewald1,2,3, Redouane Lguensat4,5, and Venkatramani Balaji1,2
Maike Sonnewald et al.
  • 1Program in Atmospheric and Oceanic Sciences, Princeton University, Princeton, NJ 08540, USA
  • 2NOAA/OAR Geophysical Fluid Dynamics Laboratory, Ocean and Cryosphere Division, Princeton, NJ 08540, USA
  • 3University of Washington, School of Oceanography, Seattle, WA 98195, USA
  • 4Laboratoire des Sciences du Climat et de l'Environnement, CEA Saclay, Institut Pierre Simon Laplace, Gif-Sur-Yvette, France
  • 5LOCEAN-IPSL, Sorbonne Universit'e, Institut Pierre Simon Laplace, Paris, France

The North Atlantic ocean is key to climate through its role in heat transport and storage, but the response of the circulation’s drivers to a changing climate is poorly constrained. The transparent machine learning method Tracking global Heating with Ocean Regimes (THOR) identifies drivers of circulation with minimal input: depth, dynamic sea level and wind stress. Beyond a black box approach, THOR's predictive skill is transparent. A dataset is created with features engineered and labeled by an explicitly interpretable equation transform and k-means application. A multilayer perceptron is then trained, explaining its skill using relevance maps and theory. THOR reveals a weakened circulation with abrupt CO2 quadrupling, due to a shift in deep water formation areas and locations of the Gulf Stream and Trans Atlantic Current transporting heat northward. If CO2 is increased 1% yearly, similar but transient patterns emerge. THOR could accelerate model analysis and facilitate process oriented intercomparisons.

How to cite: Sonnewald, M., Lguensat, R., and Balaji, V.: Revealing mechanisms of change in the Atlantic Meridional Overturning Circulation under global heating, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-6321, https://doi.org/10.5194/egusphere-egu21-6321, 2021.

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