Scattering of light by large nonspherical particles: ray-tracing approximation versus T-matrix method

Area of Science:

• Atmospheric Optics
• Computational Physics
• Radiative Transfer Theory

Background:

• Accurate light-scattering computations are crucial for understanding atmospheric radiative transfer.
• Nonspherical particles significantly influence light scattering properties in the atmosphere.
• Evaluating approximations against exact methods is essential for computational efficiency.

Purpose of the Study:

• To compare light-scattering computations for spheroids using geometric-optics approximation and the T-matrix method.
• To assess the accuracy of the geometric-optics approximation for nonspherical particles.
• To determine the applicability of the geometric-optics approximation for various scattering parameters.

Main Methods:

• Light-scattering computations for randomly oriented, moderately absorbing spheroids.
• Comparison between geometric-optics approximation and the exact T-matrix method.
• Analysis of phase function and polarization computations.

Main Results:

• Geometric-optics approximation shows higher accuracy for spheroids than for spheres.
• The approximation is suitable for phase function computations with size parameters as low as 60.
• Differences in single-scattering albedo between methods are minimal, even for small size parameters.

Conclusions:

• The geometric-optics approximation is a viable and accurate tool for light-scattering phase function computations of spheroids.
• The method's limitations exist for polarization computations.
• Findings support the use of geometric-optics approximation for efficient modeling of atmospheric light scattering by nonspherical particles.