Can Turbulence Suppress Double-Diffusively Driven Interleaving Completely?

Abstract

A linear stability problem is formulated to investigate the effect of turbulence on double-diffusively driven thermohaline interleaving in rotating media. Three cases are considered: (a) intrusions with an alongfront slope in rotating media, (b) intrusions with zero alongfront slope in nonrotating media, (c) intrusions with zero alongfront slope, where the Coriolis force is retained. The physical reason for case c is that the large-scale vertical geostrophic shear in baroclinic fronts will rotate any intrusion with nonzero alongfront slope as long as the alongfront slope vanishes. In all three cases, turbulence works to suppress interleaving so that the growth rate of the fastest growing intrusion decreases with the increase of turbulent diffusivity k*. However, in cases a and b the growing intrusions exist for any finite value of k*, while in case c there is a marginal (maximum) value of k* beyond which growing intrusions do not exist.