| Studies on the Internal Waves by Observing the Time Variations of Water Temperature in Lake Biwa |
| Shuichi ENDOH, Shiro IMAWAKI and Hideaki KUNISHI |
| Bull. Disast. Prevent. Res. Inst. Kyoto Univ., Vol.22-B2, 591-599, 1979 |
| In order to reveal the time variations of water temperature field in the north basin of Lake Biwa, successive measurements of spatial temperature distribution were carried out using a bathythermograph for four days during 28-31 August, 1973. The horizontal distribution of observed water temperature at the thermocline depth fluctuates largely day by day. This fluctuation seems to be caused by the rotating internal wave, which has been pointed out by Kanari. At the fixed buoy station, Ie-1, time series of current and water temperature were obtained. Results show that the internal wave with the period of about 40 hours has been dominant in the fluctuations of both current and water temperature. An elliptical hodograph of this wave has been obtained and this means the Coriolis' force plays a very important role to the internal wave of the fundamental mode. It is interesting that the direction of the major axis of the ellipse almost coincides with that of the longitudinal line of Lake Biwa at this buoy station. |