Roger C. Gauss
Raymond J. Soukup
Naval Res. Lab., Washington, DC 20375
C. Scott Hayek
Johns Hopkins Univ.
Distant reverberation measurements in the surface/near-surface and air--sea interaction experiment in the Gulf of Alaska (February/March 1992) were designed to assess the Doppler and spatial characters of primarily low grazing angle reverberation as functions of frequency environmental conditions, and source steering angle. Twenty-two tests using cw and HFM pulses of 8- to 12-s duration were conducted during a variety of sea conditions, at wind speeds ranging from 4 to 19 m/s. These data were collected simultaneously at two frequencies (usually 250 and 1000 Hz). The data illustrate the contrast in the spectral and temporal characteristics of long-range reverberation (20 to 30 km) between low sea states where fish scattering is important and higher sea states where subsurface bubbles are important.