title: Enhanced diapycnal mixing by salt fingers in the thermocline of the tropical Atlantic.
abstract: Diapycnal mixing plays a significant role in the ocean's circulation and uptake of heat and carbon dioxide, but has not been quantified in salt finger-driven thermohaline staircases. We recently performed a tracer release experiment in the western tropical Atlantic staircase at approximately 400 m depth. The observed dispersion implies an effective diapycnal diffusivity for tracer and salt of 0.8 to 0.9 x 10(-4) m2/s. Temperature microstructure data interpreted in terms of a vertical production-dissipation balance yields a smaller effective diffusivity for heat of 0.45 (+/- 0.2) x 10(-4) m2/s, consistent with salt fingers and well above the mixing ascribable to mechanical turbulence.
authors.affiliation: Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA.
authors.forename: R W
authors.initials: RW
authors.lastname: Schmitt
authors.forename: J R
authors.initials: JR
authors.lastname: Ledwell
authors.forename: E T
authors.initials: ET
authors.lastname: Montgomery
authors.forename: K L
authors.initials: KL
authors.lastname: Polzin
authors.forename: J M
authors.initials: JM
authors.lastname: Toole