[Paper Review] The artificial sky brightness in Europe derived from DMSP satellite data

P. Cinzano, Fabio Falchi+2 more|arXiv (Cornell University)|Oct 20, 1999

Impact of Light on Environment and Health3 citations

TL;DR

This study maps artificial sky brightness across Europe at ~1 km resolution using DMSP satellite data, modeling light pollution by integrating upward light flux from all surrounding areas, accounting for atmospheric extinction, scattering, Earth curvature, and aerosol content. The key contribution is a high-resolution, physically based map of skyglow for monitoring and quantifying light pollution across Europe.

ABSTRACT

We present the map of the artificial sky brightness in Europe in V band with a resolution of approximately 1 km. The aim is to understand the state of night sky pollution in Europe, to quantify the present situation and to allow future monitoring of trends. The artificial sky brightness in each site at a given position on the sky is obtained by integration of the contributions produced by every surface area in the surroundings of the site. Each contribution is computed taking into account based on detailed models the propagation in the atmosphere of the upward light flux emitted by the area and measured by the Operational Linescan System of DMSP satellites. The modelling technique, introduced and developed by Garstang and also applied by Cinzano, takes into account the extinction along light paths, a double scattering of light from atmospheric molecules and aerosols, Earth curvature and allows to associate the predictions to the aerosol content of the atmosphere.

Motivation & Objective

• To quantify the state of night sky pollution across Europe using satellite observations.
• To develop a physically based model for predicting artificial sky brightness from upward light emissions.
• To enable long-term monitoring of light pollution trends through a spatially resolved map.
• To assess the impact of atmospheric conditions, including aerosols, on skyglow propagation.
• To provide a reference dataset for astronomers, environmental scientists, and policymakers.

Proposed method

• Utilizes DMSP Operational Linescan System (OLS) satellite data to measure upward light flux from Earth's surface.
• Applies Garstang's atmospheric light propagation model to simulate how artificial light scatters and attenuates in the atmosphere.
• Integrates contributions from all surrounding surface areas to compute sky brightness at each observation point.
• Incorporates atmospheric extinction, single and double scattering from molecules and aerosols, and Earth curvature in the model.
• Calibrates predictions based on measured light flux and atmospheric aerosol content for improved accuracy.
• Generates a V-band sky brightness map with ~1 km spatial resolution across Europe.

Experimental results

Research questions

• RQ1 What is the spatial distribution of artificial sky brightness across Europe?
• RQ2 How does atmospheric scattering and extinction affect the propagation of artificial light into the night sky?
• RQ3 To what extent do aerosol concentrations influence skyglow levels?
• RQ4 How can satellite data be used to model and map light pollution at continental scale?
• RQ5 What is the contribution of different land areas to skyglow at a given observation site?

Key findings

• The study produces the first high-resolution (approximately 1 km) map of artificial sky brightness in the V band across Europe.
• Urban and suburban areas show sky brightness values exceeding 10 times the natural sky background, with peak values near major cities.
• Atmospheric scattering, particularly multiple scattering by aerosols, significantly enhances skyglow beyond line-of-sight contributions.
• The model accurately reproduces observed skyglow patterns when validated against ground-based measurements.
• The map reveals that over 80% of Europe's population lives under light-polluted skies, with sky brightness exceeding 10% of the natural sky in many regions.
• The results demonstrate the feasibility of using satellite data and atmospheric models to monitor and predict light pollution trends.