An ocean-atmosphere radiative model (OARM) evaluates irradiance availability and quality in the water column to support phytoplankton growth and drive ocean thermodynamics. An atmospheric component incorporates spectral and directional effects of clear and cloudy skies as a function of atmospheric optical constituents, and spectral reflectance across the air-sea interface. An oceanic component evaluates the propagation of spectral and directional irradiance through the water column as a function of water, five phytoplankton groups, and chromophoric dissolved organic matter. It tracks the direct and diffuse streams from the atmospheric component, and a third stream, upwelling diffuse irradiance. The atmospheric component of OARM was compared to data sources at the ocean surface with a coefficient of determination (r2) of 0.97 and a root mean square of 12.1%.Gregg, Watson W. and Suarez, Max J. (Editor)Goddard Space Flight CenterOCEAN MODELS; ATMOSPHERIC MODELS; AIR WATER INTERACTIONS; IRRADIANCE; OCEANS; PHYTOPLANKTON; THERMODYNAMICS; SPECTRAL REFLECTANCE; DISSOLVED ORGANIC MATTER; MEAN SQUARE VALUES...