Spectral remote sensing reflectance of the water surface collected at multiple stations, cruise DP05, May 2017

Remote sensing reflectance, Rrs(λ), is used for validation of airborne and satellite ocean color measurements. Inverse models also employ Rrs measurements to estimate the bio-optical properties of near-surface waters or shallow benthic environments. It has been used to detect algal blooms, floating vegetation. The presence of oil also alters the water’s specular reflectance properties, and thus the measured Rrs. Rrs(λ) is measured from the ship using a handheld spectroradiometer. Multiple measurements of the light reflected from the water’s surface, a portion of the sky, and a calibrated, diffuse reflectance reference plaque are made using a spectroradiometer with a limited field of view. The Rrs measurement is most reliable during moderate solar elevations, using observational angles consistent with remote sensing protocols. Multiple radiance measurements are combined in the computation of Rrs(λ). Measurements were collected in the northern Gulf of Mexico from May 2-12, 2017.