ASA 129th Meeting - Washington, DC - 1995 May 30 .. Jun 06

5pUW7. Low-frequency volume scattering measurements from the central Mediterranean.

Mark J. Vaccaro

Naval Undersea Warfare Ctr., New London, CT 06320

Broadband (200--1500 Hz) measurements of direct path volume scattering were made in May of 1991 in the central Mediterranean's Ionian Sea and adjacent Medina Bank. Acoustic sources used in these measurements were explosive charges detonated several hundred meters below a vertical line array (VLA) receiver. Reverberation was processed from the upward looking end-fire beam of the VLA yielding highly resolved scattering strengths in depth and frequency for the upper 400 m of the water column. Analysis of the spectral characteristics of the volume scatter data reveals that the dominant scattering emanates from diffuse, broadband strata which are confined to the thermocline region of the water column. The applicability of classic swimbladder scattering models to describe these layers is presented in addition to the spatial variability observed in volume scatter from deep (Ionian Sea) to shallow (Median Bank) ocean areas.