Looking for the Best Light Transmission Model for the Earth’s Atmosphere and Natural Waters

Leonid Sokoletsky1, and Vladimir Budak2

1. State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China

2. Moscow Power-Engineering Institute (Technical University), Moscow 111250, Russia

Abstract: Transmission of light is one of the key optical processes in the Earth’s atmosphere and natural waters, and transmittance (T) is an optical parameter showing the rate of change of irradiance with the optical depth. A knowledge of T or another optical parameter, diffuse attenuation coefficient, Kd, steady connected with the T, allows many practical tasks to be solved regarding the ocean and atmospheric optics, such as water quality, primary production, and atmospheric correction. Therefore, knowledge of the reliable relationships between T (or Kd) and such parameters as incident illumination angle, cloud coverage, diffuseness of irradiance, and inherent optical properties (such as the scattering phase function, backscattering probability, scattering asymmetry parameter, and single-scattering albedo) is crucial. We have analyzed the impact of these parameters on the T and Kd. We computed T and Kd using a synthetic dataset covering any possible values of parameters by the numerical method (MDOM) and 21 analytical models and compared results with the MDOM solutions. An analysis of individual models has shown that the best of them yield average errors for T and Kd better than 10% for the majority of real optical conditions in the Earth’s atmosphere and natural waters.

Key words: transmittance, radiative transfer, Earth’s atmosphere and natural waters