Features of the internal tide in the Peter the Great Gulf (the Sea of Japan)

Abstract

Analysis of the peculiarities of internal tide and spatiotemporal structure of internal wave bores in the Posyet Bay (Peter the Great Bay) was carried on the basis of the data obtained in different years on hydrophysical range of the Pacific Oceanological Institute, FEB RAS. It is established that specific density stratification with maximum of buoyancy frequency located in the near-bottom layer forms in autumn in the coastal area of the Bay. In autumn 2012 in the Bay, with frequencies close to 12 hours, several high-frequency internal wave packets with frequencies close to the maximum buoyancy frequency and amplitudes of up to 12 meters at the depth of 40 meters were registered. At that, horizontal component of orbital velocity of the fluid particles in the packet reached the extreme values (~0.14 m/s) in the near-bottom layer. It is shown that one of the registered internal wave packets is an internal wave bore, the leading edge of which has the form and parameters close to the parameters of the soliton of the extended equations of Korteweg–de Vries.