Space-continuous measurements on ocean current and chemical properties with the intelligent towed vehicle `Flying Fish'

A research project to develop observation systems for heat, momentum, and material circulation in the ocean and atmosphere was carried out by the Research Institute for Applied Mechanics, Kyushu University, from 1992 to 1997. A pitch, roll, and depth controllable towed vehicle called `Flying Fish' was developed which houses an acoustic Doppler current profiler, CO₂ analyzer, and sensors for measuring temperature, salinity, dissolved oxygen, pH, turbidity, and chlorophyll. The length of the vehicle is 3.84 m, the breadth is 2.26 m, the height is 1.4 m, the weight in air is 1400 kg, and the weight in water is roughly 0 kg. Flying Fish enables us to obtain space-continuous data of physical and chemical properties efficiently in the upper mixed layer of the ocean. From 1994 to 1997, the vehicle was used for observations in the northern, southern, and central parts of the Japan Sea in a collaborative study by Japan, Korea, and Russia. Examples of data obtained are shown in this paper and the results of current velocities are compared with those taken by other observation systems.