Full-Spectral Rendering of the Earth’s Atmosphere using a Physical Model of Rayleigh Scattering

The results of a project which developed a rendering system to produce synthetic images of the Earth and its atmosphere using purely physical methods are presented. Two distinct features of this system are emphasised: (1) physically realistic models of the atmosphere’s density distribution, the spectral energy distribution of solar radiation impinging on the atmosphere and the molecular scattering of light, which is accurately described by Rayleigh’s theory, and (2) the use of wavelength sampling and reconstruction techniques for calculating spectra and colour conversion procedures to produce displayable values. Radiances leaving the atmosphere are calculated using a pseudo-parallel numerical integration technique on a restrictive version of the radiative transfer equation. Results are presented in a number of images of the Earth from various view-points including a sequence depicting the changing colour and brightness of the sky at sunset.