Response of tropical Atlantic surface and intermediate waters to changes in the Atlantic meridional overturning circulation - "RETRO"

Resolving tropical thermocline dynamics, and intermediate- and deep water variations will help elucidate the specific mechanisms linking the high and low latitude ocean. Variations driven by changes in MOC or through the ocean are best resolved with therm ocline, intermediate and deep waters proxies. We also want to test the role of tropical feedbacks to explain the rapid warming which are most strongly expressed in the North Atlantic extratropical region. These aspects of paleoclimatology are poorly con strained. Our approach here provides a novel perspective within palaeo-oceanography by applying a physical oceanographic experiment design on the selection of sites and cores. We will study changes in watermass properties across main currents in the tropi cal Atlantic Ocean (surface-, intermediate- and deep currents) operating within the MOC, identifying zonal and depth gradients, and to some extent meridional gradients given the existence of pre-existing high latitude and ice core archives. Without such c onstraints on the tropical Atlantic density and temperature structure, our understanding of the dynamics of the past ocean and climate system will remain incomplete.