ABSTRACT
In the ocean, sunlight irradiance decays exponentially and becomes colored, centered in the blue-green spectral region. In contrast, solar irradiance exiting a thick cloud bottom is uniformly distributed, both in color and intensity, and no sign of the sun disk is apparent unless the cloud is very thin. This entry describes the basic composition and properties of seawater, and why light propagates through ocean water the way it does. A simple mathematical model will be provided to describe the phenomenon.
