Atmospheric aerosols directly influence radiative transfer in the atmosphere and hence change the radiance reflected to space. They also indirectly affect the radiation budget by providing cloud condensation nucleii that lead to cloud formation. Since 1981, the National Oceanic and Atmospheric Administration (NOAA) has routinely retrieved the aerosol optical thickness over the ocean with measurements from the Advanced Very High Resolution Radiometer (AVHRR) using a single wavelength algorithm [Rao et al., 1989]. Continuous efforts have been made in recent years to collect ground in situ measurements and remotely retrieve aerosol optical properties using air-and spaceborne sensors [King et al., 1999]. The primary goals of the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) [Hooker et al., 1992], which was successfully launched on August 1, 1997, are to routinely measure global ocean color and generate ocean biooptical property products.