びわ湖の内部波の研究(II) ―On the instrumented neutrally-buoyant float―

Abstract

In order to study the internal waves in Lake Biwa, an instrumented neutrally-buoyantfloat was constructed. The float is connected with a survey ship through an acousticlink which is ejected from the flost itself, and carry the signals of depth of the float andof water temperature in the same depth.Characteristics of the responses of motion of the float which is balanced in the stateof neutrally buoyancy at a thermocline, is calculated. The amplitude ratio of the verticalmotion of the float vs. the vertical motion of water depends on the temperature gradientand frequency of water movement in the therinocline, and has a resonant frequency whichmoves toward the higher frequency range according to the increasing temperature gradient.