Horizontal ray paths of underwater sound from Heard Island to Ascension Island
✍ Scribed by Jianguo Yan; Kang K. Yen
- Publisher
- Elsevier Science
- Year
- 1995
- Tongue
- English
- Weight
- 571 KB
- Volume
- 45
- Category
- Article
- ISSN
- 0003-682X
No coin nor oath required. For personal study only.
✦ Synopsis
To interpret the received transmissions from the Heard Island Feasibility Test, we need to know the propagation paths between the source und the receivers. We have constructed the horizontal ray paths between Heurd Islund and Ascension Island by using Munk et al. 's equations (Munk et al. ( J. Phys. Oceanogr., 18, (1988) 187&98), and present the numerical results
in this paper. The ray paths exhibited multipath structure with modes I to 4 currying most of the acoustic energy to Ascension. The calculated travel times,for modes 1 to 4 were spread over 10 s und range from 6240 to 6250 s. Bv tuking 6245 + 5 s, the average, as an estimate of truvel time for the first arrival and comparing it with the estimate (6257 s) obtained by signul processing, our numerical result is found to be 12 s less than that obtuined by measurement.
This travel time discrepancy might be due to the rigidbottom assumption, the uncertainty in sound speed dutabase, und the eflects of ocean currents. The influences of currents on the truvel time are quulitatively discussed. It appears that ocean currents can he a major fuctor uflecting the computed travel time.