Relationships between water attenuation coefficients derived from active and passive remote sensing: a case study...

Area of Science:

• Ocean optics
• Remote sensing
• Coastal oceanography

Background:

• Understanding light attenuation in coastal waters is crucial for marine ecosystem studies.
• Satellite-derived diffuse attenuation coefficient (K(d)) and airborne lidar volume backscattering (α) are key optical parameters.
• Quantifying the relationship between K(d) and α can improve water property estimations.

Purpose of the Study:

• To examine the relationships between satellite-derived K(d) and airborne-derived α in coastal environments.
• To determine the optimal depth for calculating α to maximize correlation with K(d).
• To assess the contribution of K(d) to α for estimating scattering properties.

Main Methods:

• Concurrent passive (satellite) and active (airborne lidar) optical measurements were collected.
• Lidar volume backscattering (α) was computed at 532 nm wavelength and 1.1 km resolution.
• Spearman rank correlation was used to analyze the relationship between α (below 2m) and K(d).

Main Results:

• A strong correlation (up to 0.96) was found between α and K(d) when α was computed below 2 m depth.
• K(d) significantly contributed to α, indicating its importance in light scattering.
• The findings support the use of combined optical measurements for scattering estimations.

Conclusions:

• Concurrent passive and active optical measurements effectively link K(d) and α in coastal waters.
• Estimating total scattering coefficient and backscattering efficiency is feasible using these combined methods.
• This approach is particularly useful in waters lacking significant optical vertical structure.