Estimation of water circulation in Otsuchi Bay, Japan inferred from ADCP observation

Abstract

In order to understand the seasonal water circulation system of Otsuchi Bay, direct current measurements were taken by using bottom-mounted Acoustic Doppler Current Profilers (ADCPs) during two periods, from October 2003 to March 2004 and from May 2004 to October 2004. During the first observation period, a remarkable estuary-type vertical circulation was observed. An anti-clockwise circulation, flowing into the bay along the northern coast and out along the southern coast was dominant during the second observation period. It was found that this clear seasonal variation was generated by both seasonal changes of wind and tide-induced residual current