Strong Coastal Current Caused By Superposition Of Coastal-Trapped Waves And Near-Inertial Internal Waves Along The Northwest Coast Of Japan

HR: 0800h
AN: OS41A-0169 [Abstracts]
TI: Strong Coastal Current Caused By Superposition Of Coastal-Trapped Waves And Near- Inertial Internal Waves Along The Northwest Coast Of Japan
AU: * Igeta, Y
EM: igeta@affrc.go.jp
AF: Japan Sea National Fisheries Research Institute, Fisheries Research Agency, 1-5939-22 Suido-cho, Chuo-ku, Niigata-city, Niigata, 951-8121, Japan
AU: Kumaki, Y
EM: y-kumaki01@pref.kyoto.lg.jp
AF: Kyoto Institute of Oceanic and Fishery Science, Aza Odasyukuno Miyazu-city, Kyoto, 626- 0052, Japan
AU: Kitade, Y
EM: ykitade@kaiyodai.ac.jp
AF: Department of Ocean Sciences, Tokyo University of Marine Science and Technology, Konan 4-5-7, Minato-ku, Tokyo, 108-8477, Japan
AU: Matsuyama, M
EM: masaji@kaiyodai.ac.jp
AF: Department of Ocean Sciences, Tokyo University of Marine Science and Technology, Konan 4-5-7, Minato-ku, Tokyo, 108-8477, Japan
AB: Mooring observations using electro magnetic current meters were performed at 15 m depths around the Tango Peninsula located at the northwest coast of Japan from June 5 to June 27 2004 to clarify the mechanism generating a strong coastal current induced around the peninsula. Typhoon 0406 had passed through over the Tango Peninsula during the observation period. Strong current flowing along the coast on the right was observed one half-day after the typhoon’s passage, and its maximum current velocity was 53 cm s-1. The current field moved along the coast on the right with traveling speed of about 0.6 m s-1 and decreased its strength with propagating. The phenomenon was considered to be induced by superposition of the subinertial fluctuation and near-inertial fluctuation caused by the typhoon. The near-inertial energy was large in the eastern side of the peninsula. The generation mechanism of the strong current was investigated by numerical experiment using multilayer level model with realistic topography and wind stress. The model well reproduced the characteristics of the strong alongshore current. Energy flux density of the subinertial fluctuation flowed along the coast on the right, and the phenomenon was considered to be a coastal-trapped wave (CTW) induced by alongshore wind stress. The near-inertial fluctuations were found to have baroclinicity and construct complex oscillation system around the peninsula. A part of the energy flux density of the near-inertial fluctuation originated from the eastern offshore region of the peninsula was trapped by the eastern coast of the peninsula. In the offshore region, the near-inertial fluctuations were considered to be near-inertial internal gravity waves induced by the typhoon. To clarify the energy concentration process of near-inertial fluctuation to the eastern coast of the peninsula, propagation characteristics of near-inertial internal waves around simplified peninsula were then investigated by additional numerical experiment. It was found that scattering of the near-inertial internal waves occurred around tip of the simplified peninsula, and a part of the energy was trapped and propagated along the coast as internal Kelvin wave.
DE: 4217 Coastal processes
DE: 4255 Numerical modeling (0545, 0560)
DE: 4508 Coriolis effects
DE: 4544 Internal and inertial waves
DE: 4562 Topographic/bathymetric interactions
SC: Ocean Sciences [OS]
MN: 2007 Fall Meeting