Studies of the Internal Wave in Small Lakes (II)

- Effect of the Lake Basin Shape on the Internal Wave -

Abstract

Using the two-layer model, numerical calculations were made for 24 small lake models. Two types of internal wave are noted dominantly. The one rotates counterclockwise round the basin by the effect of the earth's rotation, and the other clockwise. The former is characterized by the uninodal longitudinal mode in the zero-rotation case and the latter is the uninodal transverse one. Due to the lake basin shape, the period of the counterclockwise internal wave is prolonged. The island makes the period of the clockwise internal wave longer. When the length of the minor axis is shortened by the lake basin shape, the clockwise internal wave is not dominant in the complex figure model or its period becomes shorter than that of the rectangular lake model. There are cases where the magnitude of displacement of two internal waves is reversed at some position in the lake. The effect of the lake basin shape is larger on the clockwise internal wave than on the counterclockwise one.