Asymmetry of AMOC Hysteresis in a State‐Of‐The‐Art Global Climate Model

Abstract We study hysteresis properties of the Atlantic Meridional Overturning Circulation (AMOC) under a slowly‐varying North Atlantic (20°N–50°N) freshwater flux forcing in state‐of‐the‐art global climate model (GCM), the Community Earth System Model. Results are presented of a full hysteresis sim...

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Bibliographic Details
Published in:Geophysical Research Letters
Main Authors: René M. vanWesten, Henk A. Dijkstra
Format: Article in Journal/Newspaper
Language:English
Published: Wiley 2023
Subjects:
ocean circulation
tipping
CESM
hysteresis
sea‐ice
Geophysics. Cosmic physics
QC801-809
North Atlantic
Sea ice
Online Access:https://doi.org/10.1029/2023GL106088
https://doaj.org/article/0dc1d032882a4e22aeee4ff517cf6882
Description
Summary:Abstract We study hysteresis properties of the Atlantic Meridional Overturning Circulation (AMOC) under a slowly‐varying North Atlantic (20°N–50°N) freshwater flux forcing in state‐of‐the‐art global climate model (GCM), the Community Earth System Model. Results are presented of a full hysteresis simulation (4,400 model years) and show that there is a hysteresis width of about 0.4 Sv. This demonstrates that an AMOC collapse and recovery do not only occur in conceptual and idealized climate models, but also in a state‐of‐the‐art GCM. The AMOC recovery is about a factor six faster than the AMOC collapse and this asymmetry is due to the major effect of the North Atlantic sea‐ice distribution on the AMOC recovery. The results have implications for projections of possible future AMOC behavior and for explaining relatively rapid climate transitions in the geological past.

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