About a Possible Frontogenetic Role of Salt Finger Type Convection in the Ocean

Abstract

The fundamental problem of the study of oceanic fronts is to find the mechanisms that play an essential role in the generation of fronts (frontogenesis) of planetary scale and to maintain them. To study this problem with regard to the North Atlantic Ocean the fields of horizontal temperature (and salinity) gradients in the intermediate water column have been compared for the first time to the field of density ratio that characterizes the spatial inhomogeneity of vertical heat and mass transfer due to the processes of double diffusion of heat and salt. The comparison shows the presence of more or less sharp thermohaline frontal zones throughout the periphery of the two vast areas in the subtropical and tropical zones covered by intense differential-diffusion convection in the salt finger regime. This is a strong argument for the fact that this previously ignored small-scale (experiencing impact of molecular processes) convection may be a prime cause of large-scale frontogenesis in the oceanic water column.