

Ma, JJ, Yang, SZ, Wang, XB, Qiao, YL (2006). Atmospheric correction: Computing atmospheric diffuse transmittance. ATMOSPHERIC RESEARCH, 80(1), 114. Abstract If we can accurately compute the leavingwater radiance and atmospheric diffuse transmittance, we will accurately retrieve the atmosphere optical properties over the case 11 water by MODIS image. According to the paper by Wang [Wang, Menghua, 1999. Atmospheric correction of ocean color sensors: computing atmospheric diffuse transmittance. Appl. Opt. 38, 451455] to using the reciprocal equation derived by Yang and Gordon [Yang, H., Gordon, H.R., 1997. Remote sensing of ocean color: assesment of waterleaving radiance bidirectional effects on atmospheric diffuse transmittance. Appl. Opt. 36, 78877897] for atmospheric diffuse transmittance of the oceanatmosphere system, we examined the accuracy of an analytical equation proposed by Gordon et al. [Gordon, H.R., Clark, D.K., Brown, J.W., Brown, O.B., Evans, R.H., Broenkow, W.W, 1983. Phytoplankton pigment concentrations in the Middle Atlantic Bight: comparison of ship determinations and CZCS estimates. Appl. Opt. 22, 2036] in computing the atmospheric diffuse transmittance for wavelengths from MODIS band I central wavelength to MODIS band 7 for central wavelength both a pure Rayleigh and a twolayer Rayleighaerosol atmosphere overlying a rough ocean surface. It was found that for viewing angles up to approximately 40 degrees, the analytical formula produces errors between 3% and 4% for nonabsorbing and weakly absorbing aerosols and for aerosol optical thicknesses tau(a)<=0.4. The error increases with an increase in aerosol absorption, aerosol optical thicknesses, and viewing angle, and with the decrease of wavelength. By a simple numerical fit to modify the analytical formula, the atmospheric diffuse transmittance can be accurately computed usually to within similar to 1% for a variety of aerosol models, aerosol optical thicknesses tau(a)<= 0.6, viewing angles theta <= 60 degrees, different aerosol vertical structure distribution, and for wavelengths from MODIS band 1 central wavelength to MODIS band 7 central wavelength. (c) 2005 Elsevier B.V. All rights reserved. DOI: 10.1016/j.atmosres.2005.06.003 ISSN: 01698095 