The Consequences of Altered Phase in Near-Inertial Variability in Submesoscale Eddies in a Plume Front

Submesoscale eddies in the Mississippi/Atchafalaya river plume front are diurnally forced with a land-sea breeze, nearly resonant with the local inertial frequency, causing in significant diurnal variability. Analysis of a realistic regional ocean model shows that the interaction between the eddies and the near-inertial variability enhances mixing along eddy fronts. The negative relative vorticity within the eddies reduces the local inertial frequency; this can trap near-inertial wave energy, but it can also shift the phase of the response. Numerical simulations show that near-inertial variability has a different phase inside and outside the eddies. This can lead to localized regions of convergence and divergence along the edges of the eddy that propagate around the eddy edge over an inertial period. This mode of near-inertial motion interaction with eddies is explored in terms of its relationship with altered stratification and enhanced mixing along the eddy fronts.