Estimating the Radiance in Atmosphere-Ocean Systems With Different Atmosphere Models by Discrete Spherical Harmonics Method

Abstract

The radiative transfer in atmosphere-ocean systems with different atmosphere models is evaluated by the discrete spherical harmonics method. Four standard atmosphere models namely Tropical, MidLatitude Summer, MidLatitude Winter and U.S. Standard (1976) limited to a height of 16km are considered above an ocean. Two monochromatic radiations are considered according to the preponderance of the interaction they present with the participating medium namely ?=0.55μm for scattering by particles and ?=16.8μm for absorption and emission by water vapour and carbon dioxide. The absorption by the atmospheric gases considered is analysed by the statistical narrow-band correlated-k method. The optical properties of aerosols and water clouds considered are calculated by Mie theory. The results obtained by the proposed discrete spherical harmonics method are in agreement with those of the literature and demonstrate the efficiency and accuracy of the developed radiative transfer code. The effects of the governing parameters of the system are investigated and show that the presence of the ocean contributes to increasing the upward radiation fluxes in the atmosphere. The presence of aerosols in the atmosphere leads to downward radiance curves at ground level that show significant peaks around the zenith angle of observation ?=0°. Additionally, the presence of the cloud in the atmosphere creates a discontinuity in the radiation flux curves at the height of the cloud.