Figure 6.19. Spectral reflectance of sea water observed from an aircraft flying at 305 m over waters of different colors in the Northwest Atlantic. The numerical values are the average chlorophyll concentration in the euphotic (sunlit) zone in units of mg/m3. The reflectance is for vertically polarized light observed at Brewster's angle of 53°. This angle minimizes reflected skylight and emphasizes the light from below the sea surface. From Clarke, Ewing, and Lorenzen (1970).