Modeling and measuring anthropogenic skyglow

par Prof. Miroslav Kocifaj

mardi 9 mai 2023, 11:00 → 13:00 Europe/Paris

Salle Denise (Observatoire de Paris)

The proliferation of artificial light at night, and the light pollution it yields, is a global challenge that relates not only to cities, but also distant places otherwise being considered to be dark. It is because the urban light emissions extend many hundreds of kilometers away from their origins, crossing jurisdictional boundaries and impacting distant, protected areas such as nature reserves and national parks. 

 

There are two main factors that affect the behavior of emitted light and its potential to cause skyglow over a city. One is the Earth's atmosphere, which is the most variable element in prediction models.  The other factor is information about the emitting light source itself. When this information is incomplete or absent, it leads to approximations and assumptions whose significance scales up with increasing size of the examined areas.

 

The knowledge of the hemispherical night sky brightness produced by the ever-growing expansion of outdoor lighting systems is a necessary step for characterizing the nighttime environment and monitoring the evolution of the night sky quality, which is directly linked to what happens on the ground in terms of how outdoor lighting is used. Obtaining the all-sky, hemispherical radiance distribution produced by artificial lights is however a more demanding challenge, requiring the radiative transfer equation to be solved subject to boundary conditions.

 

The seminar will cover topics such as skyglow modeling and measurements, including the presentation of two powerful modeling tools.