Southern Ocean Plays Crucial Role in Atlantic Meridional Overturning Circulation Across Climate States

Strategic Insights -

Climate modeling data presented by researchers at Sun Yat-sen University, in collaboration with international experts, reveals the vital significance of the Southern Ocean in shaping the Atlantic Meridional Overturning Circulation (AMOC) across various climate states. The study utilizes proxy data and climate models to investigate the impact of Antarctic Bottom Water (AABW) and North Atlantic Deep Water (NADW) properties on the AMOC. According to the research, the AABW's potential density plays a crucial role in determining the AMOC depth, both in the last glacial maximum and in a warming climate.

Key Takeaways:

  • The Southern Ocean's influence on the AMOC's depth and strength is critical across climate states, as highlighted by the study's findings.
  • The research utilizes proxy data and climate models to investigate the properties of AABW and NADW, and their impact on the AMOC.
  • The AABW's potential density determines the AMOC depth in both the last glacial maximum and in a warming climate, with changes in the potential density of the AABW and the density contrast between NADW and AABW affecting the paths via which NADW returns to the surface.
  • The study emphasizes the importance of considering the Southern Ocean's role in climate modeling, particularly in understanding the AMOC's behavior across climate states.
  • Mojib Latif, Wonsun Park, and Yuming Zhang are co-authors of the study, which was led by Zhaoyang Song from Sun Yat-sen University.

Statistics:

  • The study found that the AMOC strength in the last glacial maximum and in a warming climate is insufficiently constrained, with changes in the potential density of the AABW and the density contrast between NADW and AABW producing a constraint on AMOC strength.
  • The proxy data used in the study agree on a shallow Atlantic Meridional Overturning Circulation during the last glacial maximum, extending down to 2000-2500 m depth.
  • Climate models project a similar AMOC geometry for the 21st century with rising atmospheric CO2 levels.

Sources:

  • Sun Yat-sen University
  • Nature Communications
  • Nature Portfolio
  • Nature Publishing Group