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DWBA

Source: vignettes/dwba/index.Rmd
index.Rmd

Overview

Benchmarked Validated
Theory Implementation

The distorted-wave Born approximation (DWBA) calculates monostatic backscatter from weakly contrasting fluid-like bodies represented by a segmented centerline and local radius profile.

Core idea

Linearize the scattering response in density and compressibility contrast, calculate each local cross-section, and integrate the complex contributions with their two-way phase (Chu et al. 1993; Stanton et al. 1998).

Best for

  • Weakly scattering zooplankton and other fluid-like elongated bodies
  • Arbitrary profiles that are not well represented by one sphere, cylinder, or spheroid
  • Deterministic calculations for a specified geometry and orientation

Supports

  • FLS scatterers with canonical or arbitrary body profiles
  • Density and sound-speed contrasts relative to the surrounding water
  • Frequency-dependent complex amplitude, cross-section, and target strength

Main assumptions

  • Small density and sound-speed contrasts
  • First-order Born-type scattering with no strong internal reverberation
  • A fluid-like interior without elastic shear response
  • Sufficient body discretization for the local radius and phase variation

Validation status

  • Benchmarked against the canonical spectra stored in benchmark_ts.
  • Validated against the published McGehee et al (1998) and echoSMs workflows.

Family pages

  • Implementation: object preparation, discretization, output, and comparisons
  • Theory: weak-scattering contrast and centerline integral

References

Chu, Dezhang, Kenneth G. Foote, and Timothy K. Stanton. 1993. “Further Analysis of Target Strength Measurements of Antarctic Krill at 38 and 120 kHz: Comparison with Deformed Cylinder Model and Inference of Orientation Distribution.” The Journal of the Acoustical Society of America 93 (5): 2985–88. https://doi.org/10.1121/1.405818.
Stanton, Timothy K., Dezhang Chu, and Peter H. Wiebe. 1998. “Sound Scattering by Several Zooplankton Groups. II. Scattering Models.” The Journal of the Acoustical Society of America 103 (1): 236–53. https://doi.org/10.1121/1.421110.