Cross-Shore Internal Waves in Zanpa Coastal Region of Okinawa Island

Abstract

Comprehensive field observations were made to establish a baseline of the existing tidal current structure and internal wave phenomena in a coastal region. Water temperature distributions at different depths and vertical profiles of horizontal current were examined in detail. Time series of horizontal current and near-bottom temperature fluctuations are explained by internal wave theories following two-layer and continuous density distributions. Study results show the propagation of cross-shore internal waves in an area where bottom topography is characterized by near-critical slope. Near-bottom cold internal current that flowed toward the shore significantly influenced the water temperature distributions in the region. The vertical structure of east-west horizontal current showed that its transmission was consistent with the phase propagation of theoretically calculated internal waves.