Characterization of radiance from the ocean surface by hyperspectral imaging.

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-t(lambda) and L-s(lambda) the impact of FOV is minimal at least up to measured W = 5.7 m/s 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. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement