ASA 127th Meeting M.I.T. 1994 June 6-10

1pAO6. The measurement of sound speeds in the surface wave zone.

W. Kendall Melville

Eric Terrill

Ronald C. Horn

Scripps Inst. of Oceanogr., U.C.S.D., La Jolla, CA 92093-0213

Sound-speed profiles in the surface wave zone are of direct interest for assessing the role of surface reverberation in many acoustic models. The sound-speed profiles may also be used in acoustical oceanography applications related to wave breaking, bubble distributions, and air--sea fluxes. Earlier instruments for the direct measurement of the sound-speed profile in the wave zone [e.g., Lamarre and Melville, J. Acoust. Soc. Am. 95, 1317--1328 (1994)] could be deployed for only limited periods. In this paper an autonomous surface buoy is described which is designed to measure sound speed, temperature, and conductivity, on a deep-water mooring for a period of months. The design of the instrument is based on the tethered version of Lamarre and Melville but is extended to include on-board data processing and storage of sound speeds over the first 7 m of the water column. Samples of processed data, buoy location, and other ``housekeeping'' data are recovered via an Argos satellite link. Preliminary results from the initial deployment in the North Atlantic during the 1993--94 winter will be presented. [Work supported by ONR.]