19.09.2012: Joint FB 1 / SFB 754 Seminar

Francois Ascani, University of Hawaii: "Zonal transport at intermediate depths in equatorial basins"


Mittwoch, 19. September, um 13.15 h im Gr. Konferenzraum (West).


In this presentation, I will discuss the dynamics responsible for transporting water masses and tracers in the deep equatorial Atlantic Ocean. I will briefly review the mean currents and current variability observed at depth in this region as well as previous modelling studies that aim to explain the observed deep zonal transport within the equatorial band. I will argue that there are still unanswered questions relative to1) the role played by dissipation (understood here as either diffusion of density or friction) in the deep zonal transport and 2) the relationship between dissipation, the mean currents, the wave variability and the transport. Using theory and modelling, I will clarify these relationships and will demonstrate that dissipation is key to obtain any type of transport in the unventilated layers of a closed basin. This work calls for caution for the choice of the type and level of dissipation in a numerical model aimed to study the transport in the deep ocean.