HR: 0800h
AN: OS11A-0497    [Abstracts]
TI: Scattering And Reflection Of Semidiurnal Internal Tide In Uchiura Bay
AU: * Kawamura, Y
EM: kawamura@dpc.ehime-u.ac.jp
AF: Ehime University, Center for Marine Environmental Studies, Ehime University; 2-5 Bunkyo-cho, Matsuyama, 790-8577 Japan
AU: Kitade, Y
EM: ykitade@s.kaiyodai.ac.jp
AF: Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato-ku, Tokyo, 108-8477 Japan
AU: Matsuyama, M
EM: masaji@s.kaiyodai.ac.jp
AF: Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato-ku, Tokyo, 108-8477 Japan
AB: To clarify scattering process of semidiurnal internal tide in Uchiura Bay, located at the head of Suruga Bay in Japan, mooring observations using ADCP were performed at two stations near the southern coast of Uchiura Bay in summer, 2002. These mooring systems were arrayed in cross-shore direction, and water depths of the stations are 74m and 84m, respectively. Semidiurnal internal tide was predominant throughout the observation period. The alongshore currents for semidiurnal internal tide at both stations showed maxima in upper and lower layers and the upper layer currents were approximately out of phase to the lower layer current, implying the structure of the first vertical mode. On the other hand, the cross-shore currents with semidiurnal period were larger in the middle layer at both stations and their phases delayed in the upper layer. The depth of maximum amplitude of the cross-shore current at offshore station was about 6m deeper than that at near-shore station. These features indicate the downward energy propagation and upward phase propagation, i.e., vertical propagation of internal wave. Next, we carried out numerical experiment using a three-dimensional level model with real topography to investigate the generation process of the downward propagating internal wave. The experiment result well reproduced the observed result. The downward propagating wave was found to be regenerated at shallow region of the southern coast of Uchiura Bay by a scatting process of the first-mode internal wave that has a characteristics of internal standing wave in the bay. The scattered waves were also regenerated at the bay mouth and along shore currents associated with the scattered waves were strengthened just above the sea bottom at the center of the bay, because the bottom slope is near critical for the semidiurnal internal tide. About 20 percent of the energy for the semidiurnal internal tide in the bay was estimated to be transported to small-scale internal wave by the scattering and reflection processes.
DE: 3384 Waves and tides
DE: 4544 Internal and inertial waves
DE: 1724 Ocean sciences
DE: 0629 Inverse scattering
DE: 0669 Scattering and diffraction
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting