Thermal Microstructure and Internal Waves in the Canada Basin Diffusive Staircase. (Reannouncement with New Availability Information).

摘要

Measurements of thermal microstructure in the Canada Basin thermohaline staircase are used to investigate the mechanisms of oceanic double-diffusive convection. Thermal interface thicknesses, the presence and scales of anomalous parcels near the diffusive interfaces, and an estimated decay time scale for these anomalies are all consistent with previous models based on laboratory and analytical studies in which heat transport consists of molecular diffusion through a stable interface core, intermittent separation of unstable boundary layers, and subsequent diffusion into the adjacent convective layers. It is shown, however, that in the Canada Basin shear instabilities driven by the internal wave field may significantly modify the vertical fluxes, in particular salt, and may be sufficient to reverse the direction of total buoyancy transport without destroying the staircase.