In this paper the atmospheric correction algorithms for two ocean color sensors, CZCS and SeaWiFS, were analyzed. Based upon the analysis, the 6S model was used to study the relationship between &rgr;as(&lgr;) and &rgr;a(&lgr;)+&rgr;ra(&lgr;) and to develop a new ϵ function. The new ϵ3(&lgr;,865) function considered the aerosol scattering effect and the interaction between aerosols and atmospheric molecules as a whole. Using the ϵ3(&lgr;,865) instead of the original SeaWiFS defined ϵ(&lgr;,865) could avoid the converting between &rgr;as(&lgr;) and &rgr;a(&lgr;)+&rgr;ra(&lgr;) and help to simplify the atmospheric correction algorithm to a great extent. ¿ 2000 American Geophysical Union