Semi-analytical modeling and parameterization of particulates-in-water phase function for forward angles

Area of Science:

• Ocean Optics
• Light Scattering
• Particulate Matter Analysis

Background:

• Accurate prediction of light scattering phase functions is crucial for understanding radiative transfer in aquatic environments.
• Existing models may have limitations in accurately representing forward scattering behavior based on key particulate properties.

Purpose of the Study:

• To develop a Mie theory-based model for predicting scattering phase functions at forward angles (0.1°-90°).
• To utilize particle size distribution (PSD) slope and bulk refractive index as primary input parameters.
• To provide a mathematically less complex model with desired accuracy for forward scattering.

Main Methods:

• Calculated PSD slope from hyperbolic slope of particle attenuation spectrum.
• Evaluated bulk refractive index using an inversion model with backscattering ratio and PSD slope.
• Modeled the particulates-in-water phase function for forward scattering angles (0.1°-90°) using Mie theory.
• Validated results against Petzold's average particle phase function and other models.

Main Results:

• The model successfully predicts scattering phase functions at forward angles using PSD slope and bulk refractive index.
• The methodology allows for the estimation of bulk refractive index from easily measurable optical parameters.
• The model demonstrates mathematical simplicity and achieves desired accuracy in forward scattering predictions.

Conclusions:

• The developed Mie theory model offers an accurate and efficient method for predicting forward scattering phase functions in various water types.
• This model facilitates a better understanding of light-particulate interactions in aquatic systems.
• The inversion methodology provides a practical approach to determine bulk refractive index from in situ measurements.