Flow of Antarctic Bottom Water in the Vema Channel. A Review (in English)

Morozov E. G., Frey D. I., Campos E.

We present a review of our long-term research of the bottom water flow in the Vema Channel in the South Atlantic. The Vema Channel is the main conduit for Antarctic Bottom Water between the Argentine and Brazil basins and further to the north. This channel is characterized by strong bottom flow. The bottom velocities are usually in the range 25—40 cm/s. The maximum measured velocities were as high as 60 cm/s. The total transport of Antarctic Bottom Water through the channel ranges from 1.6 to 4.0 (±0.2) Sv. The core of the coldest (θ = −0.120°C) and low salinity (34.665 psu) water is usually displaced to the eastern wall due to the Ekman friction. We used the numerical model for ocean circulations developed at the Institute of Numerical Mathematics to simulate the bottom flow in the Vema Channel. This is a σ-model based on the full system of thermo-hydrodynamic equations with the hydrostatic and Boussinesq approximations, which describes bottom currents more adequately than the z-models. Numerical simulations confirm the field measurements and reveal significant variability in the intensity and spatial structure of the velocity field in the channel.

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