Abstract

Motivated by observations of a strong near-inertial wave signal at the base of the semi-permanent anticyclonic Cyprus eddy during the 2010 BOUM experiment, a numerical study is performed to investigate the role of near-inertial/eddy interactions in energy transfer out of the mixed layer. A hybrid temporal-spatial decomposition is used to split all variables into three independent components: slow (eddy) and fast (inertial oscillations + waves), which proves useful in understanding the flow dynamics. Through a detailed energy budget analysis, we find that the anticyclonic eddy acts as a catalyst in transferring wind-driven inertial energy to propagating waves. While the eddy sets the spatial scales of the waves, it does not participate in any energy exchange. Near-inertial propagation through the eddy core results in the formation of multiple critical levels with the largest accumulation of wave energy at the base of the eddy. A complementary ray-tracing analysis reveals critical level formation when the surface-confined inertial rays originate within the negative vorticity region. In contrast, rays originating outside of this region focus at the base of the eddy and can propagate at depth.

This content is only available as a PDF.