| Seasonal Variation of Water Current in Lake Biwa Evaluated by a Diagnostic Model |
| Shuichi ENDOH, Miwa WATANABE and Yasuaki OKUMURA |
| Mem. Fac. Educ. Shiga Univ., Vol.45, 43-56, 1995 |
| Seasonal variation of water current in Lake Biwa is evaluated by a diagnostic model using three dimensional distributions of water temperature which were observed during 1989 and 1990. Geostrophic gyres develop in May and are maintained throughout summer and autumn. Current speed of the gyre reaches as much as 40 cm/s. In winter, very weak current is estimated all over the lake. Kinetic energy in Lake Biwa is large in summer and small in winter mainly caused by the development of gyres. Available potential energy is generally high in summer, but is not proportional to the intensity of the thermal stratification. This suggests the gyre is maintained not only by thermal effect but also by the wind stress. |