On several mechanisms of the formation of the compensated thermohaline inhomogeneities in the ocean

Abstract

The process of the geostrophic adjustment in the stably stratified two-component medium is studied in the framework of a linear approximation. We demonstrate that, at the final stage of that process, a stationary trace is generated by the distribution of the temperature and salinity, whose horizontal inhomogeneities mutually compensate in the field of the density. The compensation level for the stationary thermohaline distributions forming during the geostrophic adjustment is estimated. The origination mechanism of compensated thermohaline inhomogeneities in hydrodynamically stable shear flows is examined. We show that, in such flows, the disturbances of the fields of buoyancy (density), pressure, and velocity damp with time, whereas the compensated disturbances of the fields of the temperature and salinity are carried off by the flow without damping. Based on the explicit solutions of the dynamic equations, it is shown that the evolution of the compensated distribution of the temperature and salinity in the shear flows usually results in the sharpening of the spatial gradients. This feature may be, among others, related to one of the factors of the origination of the fine structure of the ocean: the small-scale thermohaline inhomogeneities, which exist against the background of the smooth vertical distribution of the density.