Characterization of Radiance from the Ocean Surface by Hyperspectral Imaging
Journal Article - Open Access
NAVAL RESEARCH LAB WASHINGTON DC WASHINGTON United States
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A novel snapshot hyperspectral imager is introduced for ocean color OC applications and its capabilities are demonstrated. The instrument provides hyperspectral radiance images with a wide field-of-view FOV and short exposure time. which is valuable for the direct characterization of the wind-roughened surface in various illumination conditions and wind speeds. Uncertainties in the total L-t, sky L-s and derived water- leaving L-w radiances at viewing angles of 20-60 degrees are determined as a function of wind speed together with associated correlation coefficients and variances of the sea surface reflectance coefficient p. Estimated L-w uncertainties can partially explain the inaccuracy of satellite retrievals in the blue bands in the coastal waters. It is shown that in above-water measurements in no-glint conditions with viewing and azimuth angles of 40 degrees and 90 degrees, respectively, for both L-tlambda and L-slambda the impact of FOV is minimal at least up to measured W 5.7 ms for full-angle FOV of 4 degrees and larger. Implications of uncertainties for the derivation of water leaving radiance in above-water ship-borne and AERONET-OC measurements are discussed.
- Physical and Dynamic Oceanography