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Subcritical penetration of narrow Gaussian beams into sediments
(NATO. SACLANTCEN, 1988/03)
Complete wave-theory solutions have been obtained numerically for both the reflected and the transmitted fields associated with a narrow Gaussian beam incident on a water-sediment interface near the critical grazing angle. ...
Computer models for underwater sound propagation
(NATO. SACLANTCEN, 1975/10)
The state of affairs of computer models for underwater sound propagation loss estimation is discussed from the viewpoints of two segments of the sonar community; i.e., (1) those who develop the models and are primarily ...
Shallow water propagation incorporating both bubble plumes and sea-surface roughness
(NATO. SACLANTCEN, 1997)
The effect of including a range dependent bubble layer and a suitable sea surface spectrum in modeling shallow water propagation is analyzed. Propagation is simulated through a hrghly accurate model based on a modified PE ...
Notes on the interpretation of ambient noise statistics
(NATO. SACLANTCEN, 1982/06)
Interpretation of statements about the character of ambient sea noise, as well as schemes to measure or model noise, are sensitive to the context or underlying view of what is essentially a stochastic process. A framework ...
Acoustic noise models
(NATO. SACLANTCEN, 1975/10)
The question of modeling the vertical directionality of ambient noise in the ocean is considered. The problem of converting from a description in terms of directional density function to a description in terms of the ...
Temporal fluctuation of backscattered field due to bioturbatioon in marine sediments
(NATO. SACLANTCEN, 1997)
Biological activity in marine sediments creates a time-varying, randomly fluctuating medium. A bio-diffusive model is proposed for predicting the temporal and spatial spectrum of sediment density fluctuations. Perturbation ...
Analysis and problems of HF acoustic coherent and incoherent simulations in shallow water
(NATO. SACLANTCEN, 1997)
Shallow water environments create complex scattering condit~ons due to the sea surface and bottom scattering mechanisms. An analysis of the effects of the scattering mechan~smso n sonar images of simple targets in shallow ...
Temporal modeling of high frequency (30-100 kHz) acoustic seafloor backscatter: shallow water results
(NATO. SACLANTCEN, 1997)
A temporal model of high frequency seafloor acoustic backscatter is presented and compared to recorded echoes from terrigenous sediments. Using acoustic properties correlated with mean grain size, the echo shapes and ...
Two dimensional internal-wave spectra
(NATO. SACLANTCEN, 1975/10)
Although spatial fluctuations of the sound speed in the ocean have a variety of causes, internal waves are thought to produce most of the fluctuations over horizontal scales ranging from several tens of metres to several ...
Deterministic propagation modelling: Part 1: Fundamental principles *Part 2: Numerical results
(NATO. SACLANTCEN, 1981/06)
The physics of sound propagation in the ocean is briefly reviewed. The wave equation is presented and a set of solutions under a variety of approximations is discussed. The consistency among these solutions is illustrated.