Particulate optical scattering coefficients along an Atlantic Meridional Transect

Area of Science:

• Ocean optics
• Marine biogeochemistry
• Remote sensing

Background:

• Particulate optical backscattering coefficient (bbp) is crucial for monitoring marine particles.
• Open ocean bbp measurements, especially in oligotrophic regions, are limited, leading to uncertainties in models and satellite estimates.

Purpose of the Study:

• To reduce uncertainties in bbp parameterizations and satellite estimates.
• To analyze a dataset from the Atlantic Meridional Transect (AMT19) to investigate bbp in surface waters.

Main Methods:

• Analysis of particulate optical backscattering coefficient (bbp) and particulate beam-attenuation coefficient (cp) data from the AMT19 cruise.
• Comparison with existing bio-optical models and previous studies.

Main Results:

• The relationship between particulate beam-attenuation coefficient (cp) and chlorophyll-a concentration aligned with established bio-optical models.
• Particulate backscattering per unit chlorophyll-a and per unit cp were higher than previously reported.
• A second-order decoupling between bbp and cp was observed in spectral slopes and diel cycles.

Conclusions:

• Accurate bbp measurements in oligotrophic oceans remain difficult.
• bbp and cp are generally coupled in surface open ocean waters but exhibit variations.
• Geographical and temporal factors influence the coupling between bbp and cp.