Coastal current in the off-Misawa, north east coast of Japan.

Abstract

The coastal current off MISAWA which is located at the north east coast of Japan (Fig. 1 ) , usually flows southward along the coast and shows various fluctuations influenced by the Tsugaru warm current and seasonal winds. This paper shows the results of current observations which were carried out in that area during winter (from Dec. 1978 to Jan. 1979) and in autumn (from Aug. to Nov. 1979). In winter, current directions are almost limited to north or south (Fig. 5), and several day period and diurnal period fluctuations are dominant (Fig. 7). In autumn, east west components normal to the coast, add to the north south current (Fig. 8 ). Specially, a semidiurnal tidel current appears in the east west components (Fig. 11). It is indicated that these phenomena are caused by an internal wave mode with seasonal thermocline. This is because the water temperature record at the site also shows a semi-diurnal fluctuation.