Energetics of M2 Barotropic-to-Baroclinic Tidal Conversion at the Hawaiian Islands

Abstract A high-resolution primitive equation model simulation is used to form an energy budget for the principal semidiurnal tide (M2) over a region of the Hawaiian Ridge from Niihau to Maui. This region includes the Kaena Ridge, one of the three main internal tide generation sites along the Hawaiian Ridge and the main study site of the Hawaii Ocean Mixing Experiment. The 0.01°–horizontal resolution simulation has a high level of skill when compared to satellite and in situ sea level observations, moored ADCP currents, and notably reasonable agreement with microstructure data. Barotropic and baroclinic energy equations are derived from the model’s sigma coordinate governing equations and are evaluated from the model simulation to form an energy budget. The M2 barotropic tide loses 2.7 GW of energy over the study region. Of this, 163 MW (6%) is dissipated by bottom friction and 2.3 GW (85%) is converted into internal tides. Internal tide generation primarily occurs along the flanks of the Kaena Ridge and ...