A Revolutionary Method of Characterizing Light Pollution Was Published in PNAS

Added by: A. Nozdrovická, 2.4.2019, 389 visit

A Revolutionary Method of Characterizing Light Pollution Was Published in PNAS
An international three-member team, led by a Slovak author, has published a revolutionary method in the PNAS journal. This method represents a new phase in the worldwide characterization of light pollution.
Light pollution is a serious threat to the environment nowadays, especially in the vicinity of large cities. The amount of light emitted from the Earth’s surface at night is so great that it is easily detected by satellites and excessive over-illumination of the environment is no longer just a problem of the developed parts of the world, such as Europe or the USA. In synergy with higher levels of air pollution in the cities, the impact on the environment is even more pronounced because aerosol and dust particles diffuse light much more effectively than gaseous components of the atmosphere and, therefore, contribute to increasing luminance of otherwise dark regions.
The contribution of large cities to skyglow can be observed over long distances, in rare cases up to 100 kilometers and the structure of the light field depends mainly on the cumulative emission function of all the light sources in a city (CEF). This function is unknown in the vast majority of cases and its direct determination is more or less impossible due to countless local light sources, their complicated spatial distribution, light emissions with different spectrums or directional redistribution of photons. On the other hand, CEF is crucial in modelling the spread of light pollution in the night-sky environment and without the function, any prediction is impossible.
At the Institute of Construction and Architecture of SAS, we developed a revolutionary theoretical model and numerical solution that makes it possible to acquire CEF from ground-based luminance/radiance measurements as a function of the zenith angle and the distance from the source. These measurements can be easily carried out with appropriately calibrated affordable DSLR cameras, as well as specialized spectroradiometers. The method brings the possibility to systematically monitor CEF within a large area and, therefore, it can initiate a new phase in the research on light pollution sources on a global scale. The theoretical model was experimentally validated by the data collected around Los Mochis in cooperation with colleagues from Mexico and the USA.
For more information, CLICK HERE.
Miroslav Kocifaj, Institute of Construction and Architecture SAS

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Emisná funkcia CEF získaná na 3 farebných filtroch. Rozdiely medzi RGB zložkami súvisia so svetelnými zdrojmi a s odrazivosťou okolitého terénu v Los Mochis.
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Teoretický model vs. experimentálne dáta získané rádiometriou nočnej oblohy