Peculiar discontinuities in small-scale currents at the shelf in the area of natural convection impact

Abstract

The variability of current velocity fields at the shelf was analyzed in the course of studies on anthropogenic impacts upon the ecosystems of coastal aquatic areas. The results revealed the appearance of drastic outbreaks of the flows of a specific structure in the impact area of the deepened runoff of low-saline waters. It was found that drastic short-term outbreaks exceeding the standard error three- to fourfold appeared occasionally at the shelf of Oahu Island, Hawaii, and enveloped almost the entire water mass. Their probability was considerably higher that the values characteristic for a Gaussian process. The studies of these outbreaks, including the data on the variability of sound-scattering layers and of temperature, allowed us to conclude that the effects observed were caused by the passage of fine eddies associated with the convection caused by the rise of low-saline waters from the ocean near-bottom layers.