Sea-viewing Wide Field-of-view Sensor observation of the east Asian seas during the March--April 2001 Aerosol Characterization Experiment-Asia shows large areas of underestimated or even negative water-leaving radiance in the blue. To investigate the cause of the problem, three cloud-free matchup stations around Japan were analyzed, where in situ measurements were made onboard R/V Ronald H. Brown at the time of satellite overpass. Using an optimization method, information on the possible composition of aerosols was obtained from sky radiance data collected onboard the ship. An iterative radiative transfer simulation was carried out in an attempt to reproduce the satellite-measured top-of-atmosphere reflectance. The resulting water reflectance and aerosol optical thickness (AOT) agreed well with in situ measurements when the effect of submicron absorbing particles was considered in the radiative transfer simulation. The error in the retrieved water reflectance was much decreased, with average values of about 6% at 412 and 443 nm for the three stations. The effect of the Asian dust was also simulated in comparison with that of small absorptive aerosols. The underestimation could not be solely attributed to Asian dust. It was also found that at one of the stations, where the presence of dust aerosols was anticipated, an aerosol model mixed with both dust and soot improved the accuracy of the estimated AOT compared with the case of soot as the only absorptive aerosol (error of 13% at 865 nm instead of 44%). Submicron absorbing particles, in addition of the Asian dust, should be considered in the optical remote sensing of east Asian waters.