Abstract
Monitoring using a thermistor array and an acoustic Doppler current profiler was carried out in the outer part of Tokyo Bay from May 20 to November 30, 2006. Current fluctuations with tidal periods were amplified during the maximum temperature period in early September. The strong current interfered with fishing operations using set nets. Although the current fluctuation was speculated to be baroclinic motion from a phase relationship among fluctuations of temperature, current and sea level, empirical orthogonal function analysis showed the dominance of a barotropic structure. Such a discrepancy in the current structure was explained by an internal tide propagating along a deep canyon in the outer part of Tokyo Bay. Furthermore, amplification of the semidiurnal internal tide and the warming of the temperature field were found to be induced by the intrusion of Kuroshio warm water. The amplification mechanism was examined using a two-dimensional model with idealized topography. It was concluded that the large amplitude of the semidiurnal internal tide is resonantly generated in the deep canyon in the outer Tokyo Bay when stratification becomes strong and the period of the internal seiche approaches the semidiurnal period.
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Acknowledgments
We wish to thank Mr. H. Hamada and Mr. K. Matsumoto of Nitiyu Giken Kogyo Co., Ltd., for their help in carrying out the observations. We also thank the captain and crew of the fisheries boat for their help in the observations. Sea level data were obtained from the Japan Oceanographic Data Center. Barometric data and wind data were obtained from the Japan Meteorological Agency. We would like to thank both agencies for their help. Monitoring during this study was made possible with the help of a subsidy from the Nippon Foundation.
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Kitade, Y., Igeta, Y., Fujii, R. et al. Amplification of semidiurnal internal tide observed in the outer part of Tokyo Bay. J Oceanogr 67, 613–625 (2011). https://doi.org/10.1007/s10872-011-0061-0
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DOI: https://doi.org/10.1007/s10872-011-0061-0