Accession Number : ADA283774

Title :   Real Time System for Practical Acoustic Monitoring of Global Ocean Temperature. Volume 3

Descriptive Note : Quarterly progress rept. no. 5, 1 Apr-30 Jun 1994


Personal Author(s) : Spiesberger, John L ; Frye, Daniel E ; Kenny, John M

Full Text :

Report Date : 30 Jun 1994

Pagination or Media Count : 199

Abstract : Work continues on all GAMOT Tasks as described in ARPA Grant No: MDA972-93-1-004. (1) Task A. Task A work remains on schedule and we have completed the following work: We are writing a new eigenray finder for use in identifying the paths which sound take from sources to the surface suspended acoustic receivers; A theoretical investigation has been conducted which has found that it is possible that ray theory can be extended to acoustic frequencies below 100 Hz; A new parabolic approximation to the acoustic wave equation has been developed. Unlike all previous parabolic approximations, the new approximation predicts delays of acoustic pulses with little error; The acoustic multipaths from the Kaneohe source have been identified at one SOSUS station using a ray tracing algorithm called ZRAY. This was a breakthrough since this is the furthest, 4000 km, that ray theory has been successfully used to understand acoustic propagation in the ocean; (2) Task B. Task B tasks and deliverables are on schedule. We have completed writing of a manuscript detailing the travel time anomaly estimates using a reduced gravity model of the northeast Pacific. We have designed an acoustic tomography assimilation method for a similar model but with spatially variable density. The plan for monitoring the Pacific Ocean for long term change is contained in the Task B section; (3) Task C. Fabrication of ten operational SSARs is continuing. Two units are being prepared for a test cruise at the AUTEC Range in August and two units are being prepared for testing in the Pacific in November. No significant delays or problems ahve been encountered; and (4) Task D. The 70 Hz source proposal was submitted to ARPA on April 19, 1994. No action has yet been taken on the proposal


Subject Categories : Physical and Dynamic Oceanography
      Acoustic Detection and Detectors

Distribution Statement : APPROVED FOR PUBLIC RELEASE