Seasonal Variability of observed Current Field and its Cause on Joban Coast in Japan

Abstract

To understand the characteristics of the current field and its seasonal variability off the Joban coast along the east coast of Japan, the continuous survey using the mooring system are performed from October 2012. The observed current was dominated by the along shore current with several days period caused by the continental shelf waves subjected to the meteorological disturbance with the seasonal variability. In addition, the cross shore current develops in summer because of the semi-diurnal internal tides caused by the strengthened density stratification. Furthermore, it is revealed that the southward mean current also has the seasonal variability by the geostrophic current with the enhanced baroclinic density fields except for the period when the warm water driven from the Kuroshio disturbance locates off the Joban coast.