Radiometric field inter-comparison of fiducial reference measurements using an open source community processor

Area of Science:

• Oceanography
• Remote Sensing
• Radiometry

Background:

• Accurate radiometric measurements are crucial for satellite ocean color validation.
• Intercomparison of different radiometer systems is necessary to assess data consistency and accuracy.

Purpose of the Study:

• To assess differences in accuracy among above-water radiometer systems (Sea-Bird HyperSAS, pySAS, TriOS-RAMSES).
• To evaluate the performance of the open-source HyperCP processor for radiometric data.
• To compare results with AERONET-OC SeaPRiSM and in-water HyperPro II systems.

Main Methods:

• A radiometric field intercomparison was conducted at the Acqua Alta Oceanographic Tower (AAOT).
• Data were processed using the HyperCP processor, considering both class-based and sensor-specific characteristics.
• Quantities E(λ), L(λ), L(λ), and R(λ) were determined, along with their uncertainties.

Main Results:

• Using sensor-specific characteristics with HyperCP yielded differences of ~2% for E(λ), L(λ), L(λ), and 2.5% for R(λ).
• Uncertainties were lower with sensor-specific characteristics (1.5%–5%) compared to class-based.
• Comparisons with SeaPRiSM showed <5% differences in blue/green bands; HyperPro II comparisons improved with specific NIR corrections.

Conclusions:

• The HyperCP processor, utilizing sensor-specific characteristics, is highly recommended for radiometric measurements.
• This approach minimizes uncertainties and enhances data quality for satellite ocean color validation.
• Accurate above-water radiometric data are essential for reliable oceanographic research and monitoring.