Investigation of the atmospheric aerosols by the visible and IR channels of the AVHRR radiometer on NOAA-6

The diffusely reflected radiation in the daytime and diffusely transmitted radiation at night from an inhomogeneous, plane parallel planetary atmosphere bounded by the ocean surface was calculated at the visible and IR region. In the daytime the effect of the solar radiation from top was taken into account. The present study has dealt with the problem of no cloud contamination in data. In the atmosphere, water vapor, molecular nitrogen, nitrous oxide, carbon dioxide and methane as absorbent constituents and aerosols as the scattering constituent were taken into account. The ocean surface as a lower boundary was simulated by many facets whose slopes are according to the isotropic Gaussian distribution 1]. It was found that it is suitable for deriving the total optical thickness in the direction of about 15 degrees away from the specular direction at 3.7μm in the daytime, with the aid of visible region of spectrum 2]. As for sea surface temperature, for a sample analysis, derived SST was within the accuracy of 1–2K at the center of the sun glint and within the accuracy of 0.5K in the rest of the region at 3.7μm in the daytime, Furthermore computational results suggest that the comparison of temperature in the daytime with that at night at 3.7μm make it possible to separate the effect of aerosols from the total optical thickness. Thus it was found from the computations that with the aid of daytime and night time data, it is possible to derive the atmospheric water vapor, aerosols and sea surface temperature simultaneously.