Accession Number : ADA320425

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

Descriptive Note : Final rept.,

Corporate Author : WASHINGTON UNIV SEATTLE APPLIED PHYSICS LAB

Personal Author(s) : Dahl, Peter H. ; Plant, William J.

PDF Url : ADA320425

Report Date : 14 JAN 1997

Pagination or Media Count : 20

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.

Descriptors :   *BACKSCATTERING, *ACOUSTIC SCATTERING, HIGH FREQUENCY, OCEAN SURFACE, ACOUSTIC WAVES, ANALYSIS OF VARIANCE, MICROWAVES, PROBABILITY DENSITY FUNCTIONS, ACOUSTIC MEASUREMENT, WIND VELOCITY, AIR WATER INTERACTIONS, SPECTRUM ANALYSIS, ACOUSTIC DATA, GRAZING ANGLES.

Subject Categories : Acoustics

Distribution Statement : APPROVED FOR PUBLIC RELEASE