Speaker : Alma Carolina Castillo Trujillo (SIO Postdoc)
Title: Spatial variations of Near-inertial Oscillations south shore of Oahu, Hawaii
Abstract: This presentation will examine near-inertial oscillations and their interactions with motions at other frequencies using ocean surface velocities observed from High-Frequency Doppler Radar (HFDR) in the south shore of Oahu, Hawaii. I will focus on describing the spatial variations of surface Near-Inertial Oscillations (NIOs) observed in the presence of high Rossby number flow. Sea Surface Height (SSH) observations were used alongside those from the HFDR to isolate the mesoscale and submesocale parts of the flow, and test their influence on the spatial distribution of NIO frequency and amplitude using prevailing theories on wave-mean flow interaction. No discernible impact by the high Rossby number submesoscale flow on NIO frequency was detected. The amplitudes of the NIOs, on the contrary, appear modified by the submesoscale flow. Moreover, an energy budget indicated areas where this flow lost and gained energy to the NIOs. NIO wavelengths were estimated at about 100 km, one order of magnitude smaller than what previous studies have shown. These results have implications to the global energy budget of the ocean since the size, decay and growth of surface NIOs contributes to the generation of internal waves and mixing in the interior.