Sack Lunch Seminar (SLS)

Modeled Near-Inertial Wave Trapping in the Negative Vorticity Core of the Gulf
Stream



Drifting profiling floats deployed as part of the CLIVAR Mode Water Dynamics
Experiment (CLIMODE) reveal a marked depression of the frequency of
near-inertial motions in the presence of negative relative vorticity associated
with the Gulf Stream. According to previous model, observational, and
theoretical studies, near-inertial motions with intrinsic frequency below that
for a resting ocean can become trapped in regions of negative vorticity (Kunze
1984, Kunze 1995, Danioux 2008). These trapped waves are thought to undergo a
rapid transfer of energy to small vertical scales, which is then lost through
shear-instability processes which result in mixing and dissipation. The goals
of the modeling study described in this seminar were to capture the
near-inertial response to wind forcing in a Gulf Stream-like jet, characterize
and quantify the resulting enhanced mixing in the negative vorticity region,
and assess the impact of that mixing on the stratification in the Eighteen
Degree water formation region.