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SDWBA

Source: vignettes/sdwba/index.Rmd
index.Rmd

Overview

Benchmarked Validated
Theory Implementation

The stochastic distorted-wave Born approximation (SDWBA) extends the weak-fluid DWBA by averaging over random phase perturbations along the body.

Core idea

Retain the local weak-scattering contributions used by DWBA, perturb their relative phases over repeated realizations, and report the mean linear backscatter response (Demer and Conti 2003; Demer and Conti 2005).

Best for

  • Krill-like and zooplankton-like targets with unresolved shape or posture variability
  • Ensemble predictions in which phase variability is part of the model
  • Assessing how deterministic interference structure changes under randomization

Supports

  • FLS geometry and material inputs accepted by DWBA
  • Configurable realization count and reference phase-scaling parameters
  • Averaged complex amplitude, linear cross-section, and target strength

Main assumptions

  • The same weak-fluid and single-scattering regime as DWBA
  • Unresolved variability can be represented by the specified phase distribution
  • Randomization modifies coherence rather than the local scattering kernel
  • Monte Carlo settings are adequate for the requested summary

Validation status

  • Benchmarked against the canonical spectra stored in benchmark_ts.
  • Validated against the CCAMLR, NOAA applet, and echoSMs implementations.

Family pages

  • Implementation: stochastic controls, reproducibility, output, and comparisons
  • Theory: random phase model and ensemble averaging

References

Demer, David A., and Stephane G. Conti. 2003. “Reconciling Theoretical Versus Empirical Target Strengths of Krill: Effects of Phase Variability on the Distorted-Wave Born Approximation.” ICES Journal of Marine Science 60 (2): 429–34. https://doi.org/10.1016/S1054-3139(03)00002-X.
Demer, David A., and Stéphane G. Conti. 2005. “New Target-Strength Model Indicates More Krill in the Southern Ocean.” ICES Journal of Marine Science 62 (1): 25–32. https://doi.org/10.1016/j.icesjms.2004.07.027.