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

1aAO1. Acoustic monitoring of environmental pollution.

Marshall H. Orr

Naval Res. Lab., Code 7120, 4555 Overlook Ave., S.W., Washington, DC 20375-5350

High-frequency acoustic backscattering systems have been used to detect, track, and estimate dispersion coefficients for particles formed or released during ocean dumping of industrial wastes. The results of work performed in the late 70's will be reviewed to illustrate: the effects of environmental variability on vertical dispersion of released particles; the types of vertical mixing processes that have been observed in the present of strong season thermoclines (large gradients in the isopycnals); the breakdown of those thermoclines during periods of high wind stress; and the difficulties that can be encountered during attempts to navigate ships and perform acoustically guided chemical water sampling in the presence of strong ocean currents and vertical shear. Calibration of acoustic systems and estimates of system sensitivity to particles of known size distribution and concentration will be discussed.