Comparison of observed and modeled reflectance around sunglint

If the sea surface were perfectly flat, a single, disc-like reflected image of the Sun would be seen at the specular reflection angle. But this is almost never seen in reality. The sea surface is always rough due to the wind, and this spreads out the image of the Sun from a disc to the speckly column we are all familiar with. The principal effect of the rough surface is to reflect the direct solar beam into a range of angles; the rougher the sea, the wider the range. In other words, the wave slope distribution determines the sunglint pattern. A scanning spectral photometer is deployed at a coastal ocean platform COVE (CERES Ocean Validation Experiment) site to measure upwelling solar radiances from the sea surface at 11 elevation angles spanning 150 degrees of azimuth. Observed reflectances around sunglint are compared to model simulations which use the classic Cox/Munk slope distribution for visible and near infrared bands. Discrepancies between observations and model simulations are discussed.