| Continuous Records of Water Currents in Lake Biwa (II) - Characteristics of Water Current in the South Basin of Lake Biwa - |
| Shuichi ENDOH, Iwao OKAMOTO, Ikuo BAN and Takuo OKAMOTO |
| Mem. Fac. Educ., Shiga Univ., Vol.32, 67-83, 1982 |
| Hydrodynamical characteristics of the south basin of Lake Biwa were studied by analyzing the continuous records of wind and current obtained at three tower stations (Sakamoto, Shina and Yabase). General feature of this shallow and narrow basin is the very week current (2-3 cm/s) with complicated time variation. Patterns and magnitudes of the current are strongly controlled by the wind over the lake. A large horizontal circulation is often formed by the continuous strong wind with longitudinal direction. This circulation is, however, easily damped by removing the wind stress. Correlation is not high between wind speed and current speed except the case of longitudinal wind direction at Shina. Surface seiches with the period of about 240 min and 70 min, are developed by the strong wind. Under the strong wind, the amplitude of the seiche is very high though oscillatory flow is invisible due to the intense wind-driven current. It has been found that the daily variation of current velocity is developed by the land and lake breeze all the year round. The wind variations with the period of 3-7 days are also dominant and the corresponding current variations can be seen at Shina. |