Task Team 3: AMOC Mechanisms and Predictability

The team is charged with assessing the physical mechanisms underlying AMOC variability and the potential predictability of the AMOC. Both natural and anthropogenically-induced variations are being pursued. 

View TT3 Near- and Long-Term Priorities


US AMOC Task Team 3 Members
Michael Spall, chair Woods Hole Oceanographic Institution
Aixue Hu, vice-chair National Center for Atmospheric Research
Annalisa Bracco Georgia Institute of Technology
Grant Branstator National Center for Atmospheric Research
Paola Cessi Scripps Institution of Oceanography
Ping Chang Texas A&M University
Wei Cheng NOAA Pacific Marine Environmental Lab
Alan Condron Woods Hole Oceanographic Institution
Gokhan Danabasoglu National Center for Atmospheric Research
Timothy DelSole George Mason University
Tom Delworth NOAA Geophysical Fluid Dynamics Laboratory
William Dewar Florida State University
Shenfu Dong University of Miami/NOAA Atlantic Oceanographic and Meteorological Laboratory
Alexey Fedorov Yale University
Marlos Goes University of Miami/NOAA Atlantic Oceanographic and Meteorological Laboratory
Benjamin Harden Woods Hole Oceanographic Institution
Chris Hill Massachusetts Institute of Technology
Quentin Jamet Florida State University
Who Kim National Center for Atmospheric Research
Sang Ki Lee NOAA Atlantic Oceanographic and Meteorological Lab
Wei Liu University of California, Riverside
Cécile Penland NOAA Earth System Research Laboratory
Robert Pickart Woods Hole Oceanographic Institution
Rui Ponte Atmospheric and Environmental Research
Anastasia Romanou Columbia University/NASA Goddard Institute for Space Studies
Tony Rosati NOAA Geophysical Fluid Dynamics Laboratory
Andreas Schmittner Oregon State University
Fillipos Tagklis Georgia Institute of Technology
Eli Tziperman Harvard University
Wilbert Weijer Los Alamos National Lab
Nico Wienders Florida State University
Xiaobiao Xu Florida State University
Steve Yeager National Center for Atmospheric Research
Jiaxu Zhang Los Alamos National Laboratory
Rong Zhang NOAA Geophysical Fluid Dynamics Laboratory


Near-term priorities

  • Investigate how surface exchanges of buoyancy and momentum between the ocean and the atmosphere/cryosphere drive the AMOC circulation across a broad range of timescales from monthly to millennial (i.e., quasi-steady-state).
  • Clarify the apparent disagreement between models of different complexity regarding i) the role of Southern Ocean wind and ii) the role of Nordic Seas overflows in maintaining and modulating the AMOC.
  • Quantify the magnitude, location, and physical mechanisms associated with interior diapycnal mixing in the ocean, which contribute to the diabatic AMOC, and evaluate the realism of current GCMs in this regard.
  • Investigate the role of freshwater forcing and South Atlantic freshwater transports in determining the variability and stability of the AMOC.
  • Expand the use of eddy-resolving models, particularly in regional/process studies designed to: i) test the robustness of AMOC variability mechanisms identified in coarser GCMs or idealized models; ii) address the origins of persistent model bias in the North Atlantic region (e.g., Gulf Stream separation and the North Atlantic Current path); and iii) assess the role of ocean turbulence in AMOC variability.
  • Quantify the predictability properties of AMOC in idealized and comprehensive models and identify mechanisms that affect these properties.
  • Explore the mechanisms associated with AMOC variability on centennial-to-millennial timescales, and evaluate the realism of GCMs on these timescales relative to available paleo proxy data, perhaps using proxy-enabled coupled climate models.

Long-term priorities

  • Translate the knowledge developed about AMOC variability and predictability mechanisms into reliable decadal climate forecasts.
  • Incorporate mesoscale eddy-resolving ocean models more fully into the toolkit used for AMOC mechanisms/prediction studies, including long coupled GCM simulations, in order to address questions about the role of turbulence in controlling AMOC.
  • Synthesize results from theoretical, idealized models, and more complex GCM investigations into a common conceptual framework regarding key AMOC variability mechanisms and identify the resulting predictability of the AMOC.

The task team will also coordinate with the U.S. CLIVAR Decadal Predictability Working Group as well as the CLIVAR Working Group on Ocean Model Development and CLIVAR Global Synthesis and Observational Panel.