A Comparison of Simple Models of Deep Convection


OCCI Project Funded: 2003

Proposed Research

Through deep convection (vertical mixing over thousands of meters) the ocean releases large quantities of heat to the atmosphere. This process, associated with the sinking limb of the meridional overturning circulation (the ocean circulation that transports heat poleward), only occurs in a handful of regions and is a very sensitive component of our climate system. Indeed many of the hypothesized past or future climate change scenarios involve either a complete or a partial shutdown of deep convection in the North Atlantic.

Idealized models have proved to be a successful tool with which to probe the sensitivity of deep convective regions to changes in the atmosphere and ocean. In recent years, two distinct models have been used that show considerable skill in reproducing available data from the Labrador Sea: one model, formulated in terms of density layers developed by the Principal Investigator, and a second model, formulated in terms of fixed depth layers developed by German scientists. Both models suggest plausible, but different, mechanisms for the long-term variability of deep convection, including its shutdown. Through a detailed comparison of the dynamics of the two models, performed in collaboration with the German colleagues, the work proposed here seeks to reconcile the two descriptions. This effort will lead to a greater understanding of the variability of deep convection and to the development of a single, improved model.