Seabed Scattering from Low Frequency Reverberation Measurements
Final technical rept. Oct 2010-Sep 2015
GEORGIA INST OF TECH ATLANTA SCHOOL OF MECHANICAL ENGINEERING
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Low-frequency LF seabed scattering at low grazing angles LGA is almost impossible to directly measure in shallow water SW, except through inversion from reverberation. The energy flux method for SW reverberation is briefly introduced in this paper. The closed-form expressions of reverberation in an isovelocity waveguide, derived from this method, indicate that in the threehalves law range interval multimoderay sea bottom scattering with different incident and scattering angles in forming the reverberation may equivalently be represented by the bottom backscattering at a single range-dependent angle. This equivalent relationship is used to derive the bottom backscattering strength BBS as a function of angle and frequency. The LFLGA BBS is derived in a frequency band of 200 2500 Hz and in a grazing angle range of 1.1 deg 14.0 deg from reverberation measurements at three sites with sandy bottoms.
- Theoretical Mathematics
- Radiofrequency Wave Propagation