Towards a global map of the artificial all-sky brightness

TL;DR

This paper introduces a semi-analytic model to efficiently estimate artificial night sky brightness globally, enabling the creation of a comprehensive map using satellite and ground data.

Contribution

A novel two-parameter model that simplifies the calculation of artificial sky radiance, incorporating atmospheric and source emission factors for global mapping.

Findings

Model accurately predicts all-sky brightness from artificial sources.

Enables rapid computation of brightness maps using satellite and inventory data.

Facilitates development of a global artificial sky brightness map.

Abstract

Modeling the hemispherical night sky brightness of anthropogenic origin is a demanding computational challenge, due to the intensive calculations required to produce all-sky maps with fine angular resolution including high-order scattering effects. We present in this Letter a physically consistent, semi-analytic two-parameter model of the all-sky radiance produced by an artificial light source that encodes efficiently the spectral radiance in all directions of the sky above the observer. The two parameters of this function are derived from the state of the atmosphere, the distance to the observer, and the source's angular and spectral emission pattern. The anthropogenic all-sky radiance at any place on Earth can be easily calculated by adding up the contributions of the surrounding artificial sources, using the information available from nighttime satellite imagery and ground-truth lighting inventories. This opens the way for the elaboration of a global world map of the artificial all-sky brightness.