MEASUREMENTS OF ACOUSTIC SCATTERING FROM ROCKY OUTCROPS IN MONTEREY BAY
Gruber, Jenillee A.
MacMahan, James H.
MetadataShow full item record
Acoustic measurements were made off Asilomar Beach using a 200kHz split-beam echosounder. The scattering cross section was estimated using the acoustic data collected and the sonar equation. Two methods were used to estimate the grazing angle from the split-beam angle data; a flat bottom assumption and estimated bottom slopes from split-beam angle data. Scattering strength measurements demonstrated an increase as grazing angle increased and spatial variability due to bottom roughness. Scattering strength for 40 degree grazing angle ranged between -37 and -32 dB for flat bottom assumptions and -30 to -27 dB for estimated bottom slopes. The flat bottom assumption achieved an angular range of 40-65 degrees while the estimated bottom slope achieved an angular range of 10-65 degrees. Both cases were fit to Lambert's Law, with the estimated bottom slope having a Lambert parameter between -24 and -22 dB, compared to the flat bottom assumption Lambert parameters of -29 to -27 dB. Estimated bottom slopes were then qualitatively compared to high-resolution bathymetric data and were found to be in agreement. This indicates that a split-beam echosounder can be used as a remote sensing tool to estimate bottom slope features. The findings presented indicate that seafloor slope estimates from a split-beam transducer can be integrated into bottom scattering strength methods to provide improved measurements compared to flat bottom assumptions when making measurements in very rough areas.
RightsThis publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.
Showing items related by title, author, creator and subject.
Short, Billy Joe (Monterey, California: Naval Postgraduate School, 2009-06);Raman-based spectroscopy is potentially militarily useful for standoff detection of high explosives. Normal (non-resonance) and resonance Raman spectroscopies are both light scattering techniques that use a laser to measure ...
Echo Statistics of Aggregations of Scatterers in a Random Waveguide Application to Biologic Sonar Clutter Jones, Benjamin A. (Monterey, California. Naval Postgraduate School, 2012-09);Reverberation, echoes from the water column boundaries and non-target scatterers within the water column, often limits active sonar system performance. Fish can constitute a significant portion of sonar reverberation under ...
Li, Qiang; Farmer, David M.; Duda, Timothy F.; Ramp, Steven R. (American Meteorological Society, 2009-10);The performance of pressure sensor–equipped inverted echo sounders for monitoring nonlinear internal waves is examined. The inverted echo sounder measures the round-trip acoustic travel time from the sea floor to the sea ...