COMPARISON OF FIELD OBSERVATION AND NUMERICAL SIMULATION OF AOSHIO IN LAKE ABASHIRI

Abstract

Through hydraulically-field observations more than thirty times in lake Abashiri, we elucidated the all over behaviors of lake-water and compared with numerical simulation. Visualizing technique by use of ultra-sonic fish finder showed the wave-like motion of the internal boundary between the upper and the lower layer caused by strong wind. In order to clarify the phenomena, we introduced the new equations relating to the surface and internal boundary elevation, and analyzed the time-varying behavior of the boundary. We found the different wave motion of the boundary to the well-known pattern of seiche caused by strong wind. Finally, we carried out three dimensional numerical simulation regarding the transient motions of lake-water in strong wind and could make the diagram showing the appearance of Aoshio with respect to wind speed and water depth of the upper layer.