成層湖における濁水貫入層の形成機構

抄録

Several layers with high turbidity were observed in the seasonal thermocline of Lake Biwa. These layers were generated by the turbidity intrusion following the boundary mixing and the resuspension of sediments on the shore slope. The process should contribute to the vertical mixing, diffusion and redistribution of matters in stratified lakes. An intermediate nepheloid layer was found to be generated within one day, and moved vertically by the internal seiche. To investigate the mixing phenomena near a sloping boundary and turbidity intrusion into a stratified fluid, laboratory experiments were conducted using a stirring rotor and a two layer stratified water tank with a partial slope at one side. After a mixing region was developed, mixed fluid intruded horizontally into the thermocline. The behavior was discussed referring to the density difference of two layers.