Journal article
Influence of statistical surface models on dynamic scattering of high-frequency signals from the ocean surface (A)
Temporal variations of scattering of high-frequency, monochromatic signals from the ocean surface has been studied numerically. In the high-frequency domain the dynamic scattering can be modeled by a coherence function of the scattered pressure field, which is based on the Kirchhoff integral; the surface roughness is described by a spatial surface spectrum and the surface motion is described by the gravity-wave dispersion relation [D.
Dowling and D. Jackson, J. Acoust. Soc. Am. 93, 3149–3157 (1993)]. Applying some modifications to this approach, the temporal coherence function is found by numerical evaluation of a double integral. The time-varying scattering can be examined in the frequency domain by the power spectrum (the Fourier transform of the coherence function).
It is examined how a monochromatic signal is shifted and smeared in the frequency domain by comparing computations for the Pierson–Moskowitz spectrum (for a fully developed sea) with computations for the JONSWAP spectrum (for fetch-limited seas). The following results, among other issues, have been obtained: As the fetch decreases, the surface waves become shorter, leading to increasing frequency shifting of the scattered signal. [Work sponsored by the Danish Technical Research Council and the EU/MAST programme.]
Language: | English |
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Publisher: | Acoustical Society of America |
Year: | 1994 |
Pages: | 3232-3232 |
Proceedings: | The 128th meeting of the Acoustical Society of America |
ISSN: | 15208524 , 00014966 and 01630962 |
Types: | Journal article |
DOI: | 10.1121/1.411137 |