Fine vortex columns on the shelf in the area of bottom convection influence

Abstract

This paper analyzes the results of investigations into extremely large releases of current velocities registered by an acoustic Doppler profiler during experiments performed on the Hawaii shelf. An integral analysis of the variability of current fields relies on the profile data of current velocities, temperature, and acoustic-scattering layers. Based on these investigations, we proposed a hypothesis stating that the small-scale variability of currents in profiler data is conditioned by the passage of fine vortices emerging in the outflow and rise of freshened waters from a subsurface sink near the shelf edge. To confirm this hypothesis on the emergence mechanism of the observed releases of current velocities, we conducted a mathematical simulation of the response that the Doppler meter has to the passage of fine vortex, which revealed a good agreement between model calculations and experimental data. Similar phenomena were also found in the Gelendzhik Bay of the Black Sea.