On The Characteristics of Wind-Induced Current in Lake Ogawara, Japan

Abstract

Lake Ogawara is a large brackish water lake located at the northeast end of Japan’s main island. This paper presents the data of field experiment carried out in autumn of 2006 and discusses the characteristics of the vertical mixing in the halocline and the horizontal circulations in the surface mixed layer. The experiment was composed of two kinds of measurements: (1) Vertical profile of horizontal velocity was collected by three ADCPs set on the bottom of the north, the center, and the south water areas for two months. (2) Horizontal flow field was searched in wide areas from three boats equipped with ADCP in three days of November. The data from the first measurement showed a periodic appearance of intense shear layer in the halocline that seemed to be generated by internal seiche. The data from the second measurement showed the existence of rather stable currents in the surface mixed layer. These facts suggested that substances entrained from anaerobic hypolimnion by the shear motion in the halocline are carried by the stable horizontal current in the mixed layer to form uneven condition of water environment in the lake.