Documents in the NTIS Technical Reports collection are the results of federally funded research. They are directly submitted to or collected by NTIS from Federal agencies for permanent accessibility to industry, academia and the public.  Before purchasing from NTIS, you may want to check for free access from (1) the issuing organization's website; (2) the U.S. Government Printing Office's Federal Digital System website http://www.gpo.gov/fdsys; (3) the federal government Internet portal USA.gov; or (4) a web search conducted using a commercial search engine such as http://www.google.com.
Accession Number ADA571590
Title Experimentally-Based Ocean Acoustic Propagation and Coherence Studies.
Publication Date Sep 2011
Media Count 11p
Personal Author T. F. Duda
Abstract LONG TERM GOALS: The long term goal is to better understand fluctuating sound propagation conditions in two distinct ocean acoustic environment types. The first type is stratified shallow water where sound is highly bottom interacting. The second type is the mostly non bottom-interacting temperate deep-ocean sound channel. Reliable predictions of temporal and spatial variability of received underwater sound can improve processing and handling of signals of interest, including remediation of signal degradation and exploitation of available sonic information. Acoustic field fluctuations have time scales from less than a minute to hours, and horizontal spatial scales from tens of meters (as short as a few wavelengths at our lowest frequencies) to kilometers, and thus impact exploitation of underwater sound. OBJECTIVES: An overarching objective is to explain observed sound fluctuation behavior in environments with three-dimensional structure at all significant scales. For the shallow-water ocean environment, the objective is to develop knowledge of factors controlling acoustic field mean and variability (both transmission loss and phase) at frequencies from 50 to 3000 Hz. For the deep-ocean sound channel, the objective is to better characterize coupled-mode propagation at 50 to 100 Hz, which may have some behavior in common with shallow-water coupled-mode propagation.
Keywords Acoustic channels
Acoustic fields
Acoustic signals
Coherence
Deep oceans
Environments
Frequency
Handling
Horizontal orientation
Measuring instruments
Ocean environments
Propagation
Reliability
Scale
Shallow water
Sound
Sound transmission
Spatial distribution
Stratification
Temperate regions
Variations

 
Source Agency Non Paid ADAS
NTIS Subject Category 47C - Physical & Chemical Oceanography
46A - Acoustics
Corporate Author Woods Hole Oceanographic Institution, MA. Deep Submergence Lab.
Document Type Technical report
Title Note N/A
NTIS Issue Number 1316
Contract Number N00014-11-1-0194

Science and Technology Highlights

See a sampling of the latest scientific, technical and engineering information from NTIS in the NTIS Technical Reports Newsletter

Acrobat Reader Mobile    Acrobat Reader