Asymmetric Frontal Response across the Gulf of Mexico Front in Winter 2016

Abstract

The interaction of cold-vertically stratified (CVS) Mississippi River water with warm-horizontally stratified (WHS) Gulf of Mexico water resulted in a front that affected the oceanic surface layer. Our cross-frontal observations demonstrated two vertical layers. The cross-frontal deep layer (9–30 m) averaged a temperature dissipation rate (TD) varied by a factor of 1000 and was larger on the CVS side. The near-surface layer (0–9 m) averaged TD did not vary significantly across the front. The deep layer frontal asymmetry coincided with depths where the Thorpe scale was large. The situation was similar for the layer averaged turbulent kinetic energy dissipation rate (TKED). Within both layers, the averaged-TKED values were 10–30 times larger on the CVS side. The surface turbulent heat flux was up to 4 times larger on the WHS side. The observed asymmetric response of the turbulence across the front could play a significant role in the ocean-atmosphere climate system.