Accession Number:

ADA167421

Title:

Vertical Directionality of Ambient Noise: 150-300 Hz.

Descriptive Note:

Technical memo.,

Corporate Author:

SCRIPPS INSTITUTION OF OCEANOGRAPHY LA JOLLA CA MARINE PHYSICAL LAB

Personal Author(s):

• Hodgkiss,W. S.
• Fisher,F. H.

Report Date:

1986-02-07

Pagination or Media Count:

74.0

Abstract:

Measurements of the vertical directionality of ambient noise in the 150-300 Hz region have been reported. The 48 element NORDA VEKA array cut for 300 Hz and centered on the sound axis 750 m was used to collect the data. Three features of the data are striking 1 short term stability and long term fluctuations of the vertical structure, 2 asymmetry in the levels observed by the upward and downward looking beams, and 3 the existence of an underlying boxcar characteristic to the vertical structure on top of which are substantial fluctuations often taking the form of horns at or - 10-14 degrees with a significant notch in the or - 9-10 degrees region. Keywords Acoustic arrays Fast fourier transforms Contrack VIII exercise.

Descriptors:

• *ACOUSTIC ARRAYS
• *AMBIENT NOISE
• ASYMMETRY
• VERTICAL ORIENTATION
• FAST FOURIER TRANSFORMS
• DIRECTIONAL

Subject Categories:

• Acoustic Detection and Detectors
• Acoustics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE