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Characterization of 3-D underwater light fields from above the sea surface requires passive and active remote sensing
measurements. In this work, we suggest the use of passive ocean color sensors and lidar (Light Detection and Ranging)
to examine the vertical structure of optical properties in marine waters of the Northern Part of the Gulf of Alaska
(NGOA). We collected simultaneous airborne remote sensing reflectance (Rrs) in the spectral range 443-780 nm
(MicroSAS, Satlantic) and lidar-derived volume backscattering (β) profiles (0-20 m depth, wavelength = 532 nm) during
August 17 2002 in shelf waters situated south of Kodiak Island off Alaska (57.48°-58.04° N, 152.91°-151.67° W). We
evaluated the spectral response of Rrs to perturbations on vertical distribution of β by comparing the spatial variability
between aggregated (250 m horizontal resolution x 1 m vertical resolution) Rrs spectral ratios and different lidar statistics
per bin (Maximum β per bin, mean β per bin, βm, standard deviation of β per bin, βstd, integrated β per bin, βint) or
group of bins (lidar volume extinction coefficient of β between 0 and 5 m depth). Sub-surface changes of βm, βint, and
βstd were mainly correlated with Rrs (490)/Rrs (555) variability along the flight-track (Semi-partial correlation
coefficients = 0.12 to 0.21). Our results evidenced linkages between above and below-sea surface optical properties that
can be used to derive water optical constituents as a function of depth based on combined passive-active data.
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