Speaker

Kurt Polzin, Assoc. Scientist, Woods Hole Oceanographic Institution

A Brazil Basin Reprise

Abstract

A series of recent modeling studies [Drake et al. 2022, Ledwell 2024] concerning an iconic tracer release in the Brazil Basin [Polzin et al. 1997, Ledwell et al. 2000] document levels of diapycnal mixing required to explain the long term dispersion of the tracer about its target surface. The required mixing in these modeling studies is inconsistent with microstructure observations, consistent with a community myth about “Missing Mixing”.

Our hypothesis: We demonstrate that the issue is in understanding the initial evolution of the tracer. Consequently, the microstructure observations need to be taken at face value and are likely consistent with the tracer dispersion.