Tsai, John J.

Atlantic Oceanographic and Meteorological Laboratory

Four ocean dumping experiments at three different locations of both shallow and deep water (30 to 3000 m) are discussed and used to illustrate the application of acoustic remote sensing in the study of waste disposal in the ocean. The dumped materials inclu.de pharmaceutical wastes, dredged matter, and drilling fluid. Relative isoconcentration maps based on acoustic backscattered intensity measurements reveal plume structure and space-time particulate distribution of the dumped materials as well as the physical oceanographic features of the water column. Joseph and Sendner's model is applied to describe a two-process diffusion, and to calculate the apparent diffusivity, diffusion velocity, and the variance. Both the time dependence of the variance and the length scale dependence of the apparent diffusivity show good agreement with those from Okubo. On the basis of acoustic measurements, particle budget is found to decrease exponentially as a function of time in the shallow-water case. Direct and linear relationships are found among the observed acoustic intensity, measured total suspended material, theoretically calculated acoustic intensity, and total suspended material calculated from particle number and particle sizes. The analysis can be applied to other types of waste materials, and provide a new approach to monitor waste disposal in lakes, coastal zones, and open oceans.

Technical Memorandum

Office of Oceanic and Atmospheric Research (OAR)