Intermediate and High-Frequency Acoustic Backscattering Cross Sections for Water-Ice Interfaces: I. Two-Component Profile Models.
Abstract
Two general statistical-physical models (I, II) for underice surface elevations are constructed. These provide the basis for determining the intensities and associated frequency spectra of acoustic waves scattered from such water-ice interfaces. Both models embody two-component processes: the simpler model (I) represents the interface as an appropriately weighted sum of two gaussian distributions of elevation, each with different non-zero means and variances. No explicit identification of keel structure is made, however. The second model (II) does account for keel structure and assigns the gaussian components of the first model respectively to two distinct physical process: that of local iced generation and that of the intermittent, large-scale keel formation. In this report the analysis is limited to Model I and calculations of backscattering cross sections appropriate to intermediate and high frequencies ( > or = 0.1 kHz), i.e., Kirchoff-based methods. The treatment here is also restricted, for the moment, to zero gradient and single ice bottom surface interactions. In most instances, the Rayleigh numbers for both components of the underice surface are large, so that theories based solely on perturbation techniques and/or Bragg scatter are inadequate. Keywords: Underwater acoustic scattering ; Underice scattering; Scattering cross sections; Underice profile; Numerical examples; Two-component surfaces; Scattering models; Intermediate, high frequencies, backscatter intensities for small angles.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 07, 1985
- Accession Number
- ADA157533
Entities
People
- D. Middleton