In:
The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 109, No. 5_Supplement ( 2001-05-01), p. 2385-2386
Abstract:
Receptions of long-range acoustic transmissions by deep hydrophone arrays in the Pacific and Atlantic often have ‘‘ray-like’’ arrivals that occur in the shadow zone of the predicted time front. These ‘‘ray-like’’ arrivals can frequently be identified with the cusps of the predicted time front, but the receivers are up to 750 m below the depth of the cusps. Preliminary calculations show that the observed acoustic energy is not accounted for by errors in the sound speed, leakage of acoustic energy below the cusps as predicted by the full wave equation, or scattering due to internal waves. Data obtained during experiments in the Atlantic and Pacific will be reviewed. Experiments that have been conducted with receivers of vertical line arrays have not had receivers deep enough to observe this phenomena. The effect is seen when bottom-mounted or midwater acoustic sources are used. These data present a number of problems: If the ray paths are wandering all over the water column, why are predictions of ray travel times usually accurate? How does the energy loss associated with these data increase the attenuation of very long-range acoustic transmissions? Without knowing the forward problem, how can these data be used to determine oceanographic information?
Type of Medium:
Online Resource
ISSN:
0001-4966
,
1520-8524
Language:
English
Publisher:
Acoustical Society of America (ASA)
Publication Date:
2001
detail.hit.zdb_id:
1461063-2
detail.hit.zdb_id:
219231-7
