Thermohaline interleaving induced by horizontal temperature and salinity gradients from above

TL;DR

This paper introduces a new type of thermohaline intrusion driven by horizontal temperature and salinity gradients, revealing an additional horizontal mixing mechanism in ocean water masses that extends current understanding.

Contribution

It reports a novel thermohaline intrusion mechanism caused by horizontal gradients and differential double diffusive mixing rates, expanding the known conditions for such intrusions.

Findings

Intrusions generate horizontal heat and salinity fluxes towards colder, fresher regions.

Intrusions transfer density anomalies towards warmer, saltier regions.

The process extends the circumstances under which thermohaline intrusions can occur.

Abstract

In the Ocean, thermohaline intrusions and interleaving layers occur within the water mass fronts with horizontal temperature and salinity gradients, which provide an important horizontal mixing mechanism. Here we report a new type of thermohaline intrusion which is driven by the horizontal temperature and salinity gradients in the fluid layers at adjacent depths due to the different double diffusive mixing rates in the vertical direction. Once established, the intrusion layers share similar behaviors as those found within the gradient regions. Such intrusion process generates extra horizontal heat and salinity fluxes towards the cold and fresh side, but transfer density anomaly towards the warm and salty side. These findings greatly extend the circumstance where thermohaline intrusions may be observed.