Japan Marine Sci. and Technol. Ctr., 2-15 Natsushima-cho, Yokosuka 237, Japan
James F. Lynch
Arthur E. Newhall
Woods Hole Oceanogr. Inst., Woods Hole, MA 02543
In 1994, an ocean acoustic tomography experiment was performed in the Western Mediterranean Basin. It is a pilot tomography project for monitoring in this area. This project is called THETIS and constructed by European tomography groups. The S-Tether system was deployed in this experiment. This system consists of a 400-Hz tomography transceiver made by Webb Res. Co. and a surface buoy developed by WHOI and JAMSTEC. The received data from four other transceivers to the S-Tether were analyzed. The distances from S-Tether to four communicated transceivers were about 250--450 km. Sound was propagated four times a day from late January to late October in 1994. In the Mediterranean Sea, the sound velocity increases with depth from the surface down to the bottom and sound propagates in the surface sound channel. A simple inversion was used for this analysis. This method is effective for this surface sound channel. The time series of the temperature distribution was obtained. These are the vertical profiles averaged along the horizontal ranges. Seasonal changes are observed from the temperature time series. In the winter, a flat temperature distribution was covered from the surface to the bottom. It is considered to be sinking, which is a typical phenomena in the Mediterranean Sea.