[Research on Ground Feature’s Polarized Properties with Multi-Spectral and Multi-Angle AirMSPI Data]

Area of Science:

• Earth Observation
• Electromagnetic Wave Polarization

Background:

• Polarization is a key property of electromagnetic waves, vital for studying ground features.
• Accurate polarization sensors are essential for advanced earth observation.
• The Airborne Multiangle Spectro-Polarimetric Imager (AirMSPI) offers multi-band, multi-angle polarization data with high spatial resolution (~10m).

Purpose of the Study:

• Analyze the varying patterns of Degree of Linear Polarization (DOLP) and polarized Bidirectional Reflectance Factor (pBRF).
• Investigate polarization properties across different wavelengths (470, 660, 865 nm) and view zenith angles.
• Assess the potential of AirMSPI data for earth observation and parameter inversion.

Main Methods:

• Utilized experimental data from the 2013 Tracy campaign.
• Analyzed DOLP and pBRF variations with respect to incidence and view angles.
• Examined polarization characteristics of various ground features (water, vegetation, etc.).

Main Results:

• Forward scattering is rich in polarized radiation; ground features exhibit strong non-Lambertian effects.
• DOLP and pBRF correlate with the relative positions of incidence and view angles, with DOLP peaking at perpendicular directions.
• Blue bands show more polarized light due to atmospheric effects, while red/infrared bands better reveal ground feature polarization details.
• Distinct polarization signatures allow clear identification of water, artificial structures, residential areas, bare soil, and vegetation.
• Multi-scattering causes depolarization, leading to a strong negative correlation (r > -0.8) between DOLP and reflected radiation intensity.

Conclusions:

• AirMSPI provides high-quality polarization data, validating ground-based and satellite-based measurements.
• The sensor supports parameter inversion for both atmosphere and ground features.
• Polarization data offers a powerful tool for distinguishing diverse terrestrial surfaces.