Mesoscale-dependent near-inertial internal waves and microscale turbulence in the Tsushima Warm Current

Abstract This study examined characteristics of near-inertial internal waves (NIWs) associated with the background mesoscale field near Tsushima Warm Current. Observational stations off Sado Island were visited recurrently to assess spatiotemporal changes fine-scale and microscale properties seawater. Also, NIWs inspected in terms relative vorticity total strain surface geostrophic motion. During summer expeditions 2019, current hydrographic surveys at rim an anticyclonic eddy provided clear evidence downward-travelling NIWs, which most amplified depth lower pycnocline. The amplification NIW coincided elevation dissipation rates turbulent kinetic energy (TKE) variation temperature. fall 2019 expedition found details wave turbulence structure paired vortices, where a cyclone anticyclone were, respectively, adjacent east west. Amplified signals NIW-related vertical shear TKE isopycnals between dipole cores. From theoretical perspective wave, baroclinic term attributable was interpreted as inducing downward travel through pycnoclines It is also noted that cyclones, passing central part Sea Japan, can deliver into 10-km scale consequence interaction easterly wind mountainous topography Honshu Island.