Generation and propagation processes of near-inertial internal waves and coastal-trapped waves in and around Toyama Bay, Japan, calculated by high-resolution nesting ocean model

Abstract

Characteristics of near-inertial fluctuations generated by typhoon in and around Toyama Bay（TB）that opens its mouth toward the north were investigated by using results calculated by high-resolution nested ocean model which is usually operated for fisheries. From harmonic, spectral and vertical-mode decomposition analysis, we confirmed that density and current fluctuations were fundamentally characterized by propagation of coastal-trapped waves（CTWs）generated at seamount adjacent to the land tip of Noto Peninsula（NP）that is western boundary of the TB. This result in counterclockwise phase distribution in density fields. Near-inertial internal waves（NIWs）were also generated around land tip（Nyuzen）located at the eastern boundary of the TB through topographical scattering processes of the CTWs. The NIWs propagated the northwestward by way of center of the TB, finally were reflected along the eastern coast of the NP toward the northeast. The NIWs formed clockwise phase distribution in current fields, which is opposite properties against that by the CTWs. The region of strong currents confirmed around the Nyuzen was considered to be resonant-amplification of currents of the CTWs and inertial oscillations.