Global Characterization of Skyglow

web-logo-project1 No.: APVV-18-0014
Duration: 1.7.2019 – 30.6.2023
Teamleader: M. Kocifaj,
Team members: L. Kómar, J. Petržala, S. Wallner, H. A. Lamphar

In spite of the enormous progress in light pollution (LP) research since Garstang, subsequent theories are still limited to homogeneous skies, while the propagation of artificial light at night (ALAN) under broken cloud arrays remains largely unexamined. Due to its negative impacts, ALAN is currently one of the most pressing environmental concerns in the public eye. Thus major concerns were raised after experimental results showed that the predicted distributions and amplitudes of the ALAN differ from what we regularly observe in nature. Also, the mechanism of multiple scattering and optical distortion due to aerosols are both poorly described. This project will bring a fundamental understanding and satisfactory treatment of ALAN, while addressing the principal question: “How and to what extent the properties of both the artificially lit surface of Earth and the atmosphere can interact together, resulting in new means in the characterization and potential manipulation of ALAN”. We propose to 1) derive novel formulations and solutions to the light field in the nocturnal atmosphere with arbitrary cloud configurations; 2) uncover spectral “light-scattering and polarization fingerprints” that distinct types of clouds and aerosols can have in different parts of the sky; and 3) identify the manner in which both the atmosphere and light emissions from ground sources control ALAN. This could revolutionize the characterization of LP sources globally and have unexpected consequences in current developments in various fields. Overall, the project has great potential to open doors into a new research area with important applications in astronomy, lighting engineering, urban planning and also satellite remote sensing of aerosols at night, to which no competitive alternatives yet exist. The significance and novelty of the work will also lead to the acquisition of knowledge necessary to explain anomalous polarization features, or ALAN effects, due to compact and diffuse cities.