This project, entitled “Influence of Atlantic SST thresholds on continental climates: Development and application of a coupled atmosphere/ocean/vegetation regional climate model”, aims to improve our understanding of the physical processes that cause abrupt climate change, especially in association with sea surface temperature changes in the North Atlantic, and evaluate the potential for abrupt climate change over the central U.S. and northern Africa under greenhouse gas-induced climate warming.  Northern Africa and the central U.S. are chosen for the study because they are known to be prone to rapid climate change.  A number of potential mechanisms of abrupt change related to Atlantic SSTs and vegetation feedbacks have been identified and used to formulate hypotheses to guide the regional model development and application.  The process-oriented approach will help build confidence in the modeling results, as will comparisons with GCM results and paleoclimate applications.

For the central U.S., the focus will be on understanding how the regional hydrology would change due to a sudden change in the Atlantic meridional overturning circulation, and whether or not there is potential for abrupt climate change in association with land surface/atmosphere feedbacks.  Over northern Africa, we will study potential abrupt changes related to the physical processes that cause the rainfall to move into the continental interior, i.e., the processes that lead to the onset of the monsoon over the Sahel, and maintain it there for a reasonable growing season.

The research effort will produce a coupled atmosphere/ocean/vegetation regional climate model that can be adaptable to any region of interest and utilized at spatial resolutions much finer than current coupled GCMs for regional climate change studies and impact assessment.  Also relevant for broader impacts is the use of the vegetation model, which allows us to “translate” climate change scenarios into changes in vegetation, making the results more directly meaningful to policy makers.