The Variability of High-Frequency Acoustic Backscatter from the Region Near the Sea Surface. Part 2.

Abstract

Simultaneous and coincident measurements of acoustic and microwave backscatter from the air/sea interface were obtained during Phase 2 of the SAXON-FPN experiment in December 1992 and again in March 1993. The acoustic and microwave grazing angles were both set to 17 degrees, and the wavelengths were matched, being set to 2.14, 3.00, and 5.66 cm, corresponding to, respectively, acoustic frequencies of 26.5, 50, and 70 kHz and microwave frequencies of 5.3, 10, and 14 GHz. The results of our experiments show that the two scattering strengths are comparable at wind speeds below about 3 m/s but that the acoustic scattering strength increases much faster than the microwave scattering strength with increasing wind speed until reaching saturation. The temporal variability of acoustic backscattering from the region near the sea surface is examined for frequencies in the 30- to 70-kHz range. A variance spectrum of the scattering strength exhibits effects associated with three different processes described in the paper.

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Document Details

Document Type
Technical Report
Publication Date
Jan 14, 1997
Accession Number
ADA320425

Entities

People

  • Peter Hans Dahl
  • William J. Plant

Organizations

  • University of Washington

Tags

Communities of Interest

  • Air Platforms
  • Materials and Manufacturing Processes

DTIC Thesaurus Topics

  • Acoustic Measurement
  • Acoustic Scattering
  • Backscattering
  • Data Sets
  • Doppler Effect
  • Frequency
  • Grazing
  • Grazing Angles
  • Measurement
  • Microwave Frequency
  • Microwaves
  • Physics Laboratories
  • Probability
  • Probability Density Functions
  • Scattering
  • Spectra
  • Surface Waves

Fields of Study

  • Physics

Readers

  • Electromagnetic Wave Scattering and Antenna Radiation Engineering
  • Mathematics or Statistics
  • Radar Systems Engineering.