Title: Simple models of the global ocean overturning
Abstract: The global ocean overturns on time scales of hundreds of years, with important implications for climate and biogeochemistry. The configuration and magnitude of the overturning circulation is set by a variety of processes, including surface heating, atmospheric freshwater transports, diapycnal ocean mixing, ocean eddies and wind-driven upwelling. This colloquium discusses the history of how these drivers have been combined into a comprehensive dynamical framework for the overturning. This framework qualitatively explains many of the features of the overturning as simulated in models--- in particular the sensitivity to mixing coefficients, winds, and density changes. However, describing the full suite of interactions between different regions where dense water sinking occurs remains a challenge, and it is likely that our theories neglect potentially-important real-world physics. We consider the implications of what we understand, and what we do not, for how rapidly the ocean buffers the impacts of anthropogenic climate change.
