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FOIA: Environmental acoustical analysis of the Philippine Sea from Operation Church Stroke II

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posted on Nov, 25 2007 @ 12:15 PM
Environmental acoustical analysis of the Philippine Sea from Operation Church Stroke II
Environmental acoustical analysis of CW, SUS and ambient noise for the Parece Vela Basin and western Philippine Sea collected during the exercise Church Stroke II.

Document date: 1979-10-29
Department: Applied Research Laboratory, University of Texas at Austin
Author: Karl C. Focke, Jack A. Shooter, Nancy R. Bedford, Stephen K. Mitchell
Document type: report
pages: 251


Archivist's Notes: Fair quality document. DD-1472, DD-254 document cover sheets. Copy 93 of the report. Changed from Confidential to Unclassified, public release.

posted on Nov, 25 2007 @ 08:24 PM
Document from the Controlling DoD Organization: Naval Ocean Research and Development Activity, Stennins Space Center, MS 39529
Report Date: 29 October 1979
GOVT Accession No: AD C025102
Performing ORG, Report Number: ARL-TR-79-52
Performing Organization: Applied Research Laboratories, The University of Texas ,Austin

Interesting enough is that this document (free on ATS) can also be purchased for US$42.95.

Abstract: Environmental acoustical analysis of cw, SUS, and ambient noise are reported for the Parece Vela Basin and the Western Philippine Sea Basin. These data were collected during the exercise CHURCH STROKE II Cruise 5, held in the Philippine Sea during the fall of 1977. Raw acoustic data were recorded on remote bottom moored ACODAC and PAR systems. During the recording periods ambient noise, ship signatures, and storm noise were recorded as well as cw and SUS data. Bottom loss and propagation loss are reported for the different basins. The Parece Vela Basin is characterized as bottom limited and high bottom loss for grazing angles greater than 40 deg. The Western Philippine Sea Basin is characterized as an area of depth excess and high bottom loss.

Thank you for making it available here on ATS with no costs involved…

posted on Nov, 26 2007 @ 05:39 PM
This document goes ‘in depth’ into the technical and research data of the acoustic measurement systems:

• LAMDBA (large aperture mobile data base array)
• PAR (programmable acoustic receiver)
• ACODAC (acoustic data capsule)

The subjects of this report are: bottom loss, propagation loss, and ambient noise measurements from both the ACODAC and PAR systems.

Note: With looking at the nature of the sonar systems I only suspect that operation Church Stroke II assessed/tested their equipment in order to gather new information on the pro- or anti- submarine warfare.

It would be helpful if we get more information on the CHURCH STROKE exercises....

Here is a very interesting article regarding this subject from the Australian Defence Department:

Understanding the effectiveness of sonar systems is essential for assessing their operation in pro- or anti- submarine warfare. Sonar performance varies from one ocean environment to another, with large variations in detection range resulting from differences in acoustic propagation conditions. In most instances the factor which has the largest effect on long-range propagation is the sea floor. This factor also has the largest variability from one location to another. Understanding and prediction of the interaction of acoustic energy with the sea floor is complicated by the penetration of the energy into the sediments and rocks that make up the sea floor.......

[edit on 26-11-2007 by frozen_snowman]

posted on Nov, 26 2007 @ 06:21 PM

1. The document is of interest to anyone studying acoustics, particularly in a marine environment;

2. The document content concerns acoustical testing in the marine environment conducted in November 1977 in the area of the Philippines. The tests were conducted using a variety of frequencies broadcast at a variety of decibels, and monitored at a number of different depths to determine when signal loss would occur;

3. Interestingly, the research done was based on the Julian calendar;


5. Page 186 contains a diagram from a similar acoustic study done in Middle Eastern waters off Somalia and the Saudi Arabian peninsula;

6. Page 188 contains a diagram from a similar acoustic study done northeast of Hawaii and due west of the continental United States;

7. Perhaps the most interesting part of the document, for the layman, runs from page 238-250, which is the distribution list for the report;

8. Page 250 is a list of reports related to the CHURCH STROKE II study and includes the names of studies other than those listed above.

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