Ocean Color Patterns Help to Predict Depth of Optical Layers in Coastal Marine Waters
NAVAL RESEARCH LAB STENNIS DETACHMENT STENNIS SPACE CENTER MS OCEANOGRAPHY DIV
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Detection of single or multiple optical subsurface laminar features e.g. , thin layers in marine waters has many implications on ecological studies, management of fisheries, and military applications. This study has four objectives 1 to corroborate a previous index based on remote sensing reflectance ratio Rl Rrs443Rrs490 for predicting depth of lidar-derived backscattering layers 2 to evaluate at what extent these relationships hold in different marine regions, 3 to examine the nature of Rl variability in terms of inherent optical properties, and 4 to investigate the influence of water stratification on spatial distribution of Rl values Measurements of inherent optical properties absorption coefficient and scattering coefficient were obtained from a towed underwater vehicle Scanfish in three geographic locations, two in US Monterrey Bay, MB, and East Sound, ES and one in Turkish Black Sea, BS coastal waters For each site, case studies were examined based on subsurface optical layers distributed at two different depths ES 7 and 20 m, MB 7 and 20 m, and ES 15 and 27 m. R1 was theoretically derived from each Scanfish profile and the Rl skewness ip was calculated for each case study. The magnitude of the total absorption coefficient at 675 nm suggested large differences greater than 100 in trophic status between the studied areas. However, a common statistical pattern consisting of lower psi - deeper optical layer was found in all study cases. This variation was explained by optical differences above the optieline and mainly related to changes on scattering coefficient of particulates In general, skewness of R1 was more influenced by b440a440 rather than by a488b488 spatial variability. The observed relationships between psi and the depth of the optical marine layer confirmed a previous finding using airborne lidar and ocean color data.
- Physical and Dynamic Oceanography
- Optical Detection and Detectors