Arthur B. Baggeroer
Dept. of Ocean Eng., Rm. 5-204, MIT, Cambridge, MA 02139
There have been two major changes that have modulated the temperature of topics in underwater, or ocean, acoustics since the last ``hot topics'' session. First, close coupling among the acoustics, the ocean environment and its processes, numerical models, and the signal processing continues to lead to new methods for learning about the ocean and to improved performance of acoustic systems. Second, in response to the changing demands upon future sonars, there has been much more attention to both active systems and shallow water environments. Several ``hot'' (at least warm) topics will be discussed: adaptive focusing systems including phase conjugation, self-cohering arrays, and matched-field processing/tomography; global acoustics and ocean climate monitoring; high resolution bathymetric mapping; reverberation; seismoacoustics of interface waves; shallow water acoustics; ambient noise and acoustic daylight; and high data rate acoustic telemetry. (The order is not an indication of relative temperature.)