Extending aquatic spectral information with the first radiometric IR-B field observations

Area of Science:

• Aquatic remote sensing
• Optical oceanography
• Biogeochemical parameter estimation

Background:

• Aquatic radiometry has historically focused on visible wavelengths.
• Advancements in hardware and software support visible spectral analysis.
• Nonvisible wavelengths remain underexploited for aquatic ecosystem studies.

Purpose of the Study:

• To evaluate spectral limits for deriving aquatic data products using absolute radiometry.
• To investigate the utility of nonvisible wavelengths, specifically the IR-B domain, for aquatic remote sensing.
• To assess the impact of black-pixel processing on aquatic spectra and derived parameters.

Main Methods:

• Absolute radiometric field observations in the IR-B spectral domain (1400-3000 nm).
• Quality assurance of radiometric observations for individual wavebands.
• Spectral verification through celestial radiometric results, above- and in-water comparisons, and bio-optical model consistency checks.

Main Results:

• The IR-B spectral domain provides significant and variable flux signals previously underestimated.
• First absolute radiometric field observations of normalized water-leaving radiance ($$) in the IR-B domain are presented.
• Black-pixel processing demonstrably degrades aquatic spectra and derived biogeochemical parameters.

Conclusions:

• Expanding radiometric observations to nonvisible wavelengths, particularly IR-B, enhances understanding of aquatic ecosystems.
• Current black-pixel processing techniques require re-evaluation due to their detrimental effect on data quality.
• Future aquatic remote sensing should incorporate broader spectral ranges for more accurate biogeochemical assessments.