Effects of light polarization and waves slope statistics on the reflectance factor of the sea surface

• Autor(a) principal: D'Alimonte, Davide
• Data de Publicação: 2016
• Outros Autores: Kajiyama, Tamito
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.1/9512

Above-water radiometry depends on estimates of the reflectance factor rho of the sea surface to compute the in situ water-leaving radiance. The Monte Carlo code for ocean color simulations MOX is used in this study to analyze the effect of different environmental components on r values. A first aspect is examining the reflectance factor without and by accounting for the sky-radiance polarization. The influence of the sea-surface statistics at discrete grid points is then considered by presenting a new scheme to define the variance of the waves slope. Results at different sun elevations and sensor orientations indicate that the light polarization effect on r simulations reduces from similar to 17 to similar to 10% when the wind speed increases from 0 to 14ms(-1). An opposite tendency characterizes the modeling of the sea-surface slope variance, with r differences up to similar to 12% at a wind speed of 10ms(-1). The joint effect of polarization and the the sea-surface statistics displays a less systematic dependence on the wind speed, with differences in the range similar to 13 to similar to 18%. The r changes due to the light polarization and the variance of the waves slope become more relevant at sky-viewing geometries respectively lower and higher than 40 degrees with respect to the zenith. An overall compensation of positive and negative offsets due to light polarization is finally documented when considering different sun elevations. These results address additional investigations which, by combining the modeling and experimental components of marine optics, better evaluate specific measurement protocols for collecting above-water radiometric data in the field. (C) 2016 Optical Society of America