Spectral variability of airborne ocean color data linked to variations in lidar backscattering profiles

摘要

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 (R_(rs)) 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 R_(rs) to perturbations on vertical distribution of β by comparing the spatial variability between aggregated (250 m horizontal resolution x 1 m vertical resolution) R_(rs) spectral ratios and different lidar statistics per bin (Maximum β per bin, mean β per bin, βm, standard deviation of β per bin, β_(std), integrated β per bin, β_(int)) or group of bins (lidar volume extinction coefficient of β between 0 and 5 m depth). Sub-surface changes of βm, β_(int), and β_(std) were mainly correlated with R_(rs) (490)/R_(rs) (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.rnlidar, ocean color sensors, water visibility, visible spectrum, active sensors, remote sensing, vertical structure, underwater light field models