First Light Pollution Model Incorporating Heterogeneous Stochastic Cloud Fields Developed at SAS
Žilina has become a model city for groundbreaking light-pollution research that has now been published in the prestigious journal Proceedings of the National Academy of Sciences (PNAS). The model, created by researchers from the Slovak Academy of Sciences (SAS) and the Faculty of Mathematics, Physics and Informatics of Comenius University (FMFI UK), represents the first globally applicable tool capable of simulating night-time lighting conditions with a level of detail comparable to field measurements.
The developed solution accounts for realistic stochastic cloud fields with morphology and structure that naturally occur in the atmosphere. Numerical predictions were validated by experimental data, demonstrating that in large cities, low clouds can intensify diffuse night-sky brightness at the zenith by up to 27-fold and horizontal illuminance by up to 17-fold compared to a clear sky. The model further revealed the existence of a “transition zone” beyond which the effect of clouds becomes more complex — a behavior well explained by the newly developed theoretical model.
The study is accompanied by software that the Slovak researchers have made available for non-commercial scientific use. It can be linked with meteorological data to provide even more accurate predictions. This enables not only the interpretation of data from light-pollution monitoring networks, but also opens new possibilities for assessing ecological impacts in natural areas — particularly in protected regions threatened by transported light pollution from distant sources.
Text: Miroslav Kocifaj, Ústav stavebníctva a architektúry SAV, v. v. i.