PHYSICS SEMINAR (interdisciplinary)
Modeling and remote sensing of light pollution in heterogeneous environments: an attempt to understand light pollution
Martin Aubé
1) CÉGEP de Sherbrooke, Québec, Canada
2) Université de Sherbrooke, Québec, Canada
Friday, February 10, 2012
1:30 p.m.
Nicolls 213
Abstract
Light pollution is constantly growing all over the world as long as inhabited zones are growing with population. Real dark night may only be perceived in few places, mainly located on top of remote mountains like Mauna Kea (Hawai), La Palma (Canary islands) and some peaks in north Chile.
In recent years, some attempts have been made to recover in part an access to darkness. Among them, the case of the Mont-Mégantic region (Québec) may be cited as example. In 2007, this region became the first international dark sky reserve. During this project, most of the badly designed light fixtures have been replaced by more efficient ones. This conversion resulted in the recovery of sky quality as it was in the 70's. The net result is a reduction of about 40% of the light pollution and a reduction of the energy demand of about 1.8 GWh per year (150 k$ per year, 5 years payback period). This project have also had the side effect of stimulating the touristic industry in that region, since it is more attractive for amateur astronomers and people interested to environmental integrity.
In this presentation, we will define in detail the concept of light pollution and its related issues. Then we will discuss of the way we have chosen to get a better understanding of that complex and nonlinear phenomenon. More specifically we will present our spectrometer dedicated to remote sensing of light pollution along with some sample data for different sites around the world. Then we will present our heterogeneous light pollution numerical model, designed to simulate light pollution in its geographical complexity. Some conclusions will then be drawn about the behavior of light pollution. We will more specifically discuss of the most common lighting devices and their possible interference with human health and their masking effect on the starry night.
Finally, we will summarize the results of a major field campaign and associated modeling experiments conducted at the Northern European observatories in La Palma and Tenerife, Canary islands, Spain.
