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Zamorano, J., Sánchez de Miguel, A., Ocaña, F., Pila-Diez, B., Gómez Castaño, J., Pascual, S., et al. (2016). Testing sky brightness models against radial dependency: a dense two dimensional survey around the city of Madrid, Spain. JQSRT, 181, 52–66.
Abstract: We present a study of the night sky brightness around the extended metropolitan area of Madrid using Sky Quality Meter (SQM) photometers. The map is the first to cover the spatial distribution of the sky brightness in the center of the Iberian peninsula. These surveys are neccessary to test the light pollution models that predict night sky brightness as a function of the location and brightness of the sources of light pollution and the scattering of light in the atmosphere. We describe the data-retrieval methodology, which includes an automated procedure to measure from a moving vehicle in order to speed up the data collection, providing a denser and wider survey than previous works with similar time frames. We compare the night sky brightness map to the nocturnal radiance measured from space by the DMSP satellite. We find that i) a single source model is not enough to explain the radial evolution of the night sky brightness, despite the predominance of Madrid in size and population, and ii) that the orography of the region should be taken into account when deriving geo-specific models from general first-principles models. We show the tight relationship between these two luminance measures. This finding sets up an alternative roadmap to extended studies over the globe that will not require the local deployment of photometers or trained personnel.
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Bouroussis, C. A., & Topalis, F. V. (2018). The effect of the spectral response of measurement instruments in the assessment of night sky brightness. Journal of Quantitative Spectroscopy and Radiative Transfer, 216, 56–69.
Abstract: This paper deals with the errors and uncertainties in skyglow measurements caused by the variation of sky's spectrum. It considers the theoretical spectral response of common instruments that are used for light pollution assessment. Various types of light sources were used in this investigation. This study calculates the spectral mismatch errors and the corresponding correction factors for each combination of instrument and light source. The calculation method is described and the results are presented in multiple figures. Calculated data show a big variation in potential errors that can be introduced when comparing readings of diverse instruments without considering the sky spectrum variation. This makes the spectral data of the sky a mandatory input to the dark sky assessment. Useful conclusions, related to instruments with better or worse behaviour, are derived from the calculations. The paper also includes suggestions on how to conduct multi-instrument measurements with or without spectral data.
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Ściężor, T., & Czaplicka, A. (2020). The impact of atmospheric aerosol particles on the brightness of the night sky. Journal of Quantitative Spectroscopy and Radiative Transfer, 254, 107168.
Abstract: This paper analyses the impact of various types of aerosols, both of natural and anthropogenic origin, on the brightness of the night sky glow in southern Poland. The particles of particulate matter, related to the combustion of solid fuels in the winter, the volcanic or desert dust, as well as mists and haze, are considered as the artificial light scattering sources. Measurements of the brightness of the cloudless and moonless night sky were done in 2009–2016, both within the city of Krakow and in suburban areas, as well as in mountainous ones. The strong linear correlation between the brightness of such sky and the concentration of particulate matter is shown. The acoustic sounding of the atmosphere (SODAR) has indicated the possibility of a relationship between the brightness of the night sky and the amount of such particulates, which accumulate in atmospheric boundary layers. The usefulness of the theoretical model of horizontal transport of dust in the atmosphere (FAPPS) for forecasting the brightness of the night sky glow is also pointed out. A clear effect of the Saharan origin dust clouds on the brightness of the night sky glow is shown. This brightness, in the conditions of a low level of light pollution, is associated with the forecasted optical density of such clouds. It is also demonstrated, that with the thickening of mist, the impact of distant light sources on the brightness of the night sky decreases, but the one of a nearby sources becomes more significant. The conclusion states that anthropogenic particulate matter has the greatest impact on the brightness of the cloudless night sky glow in winter. In areas heavily polluted with light, fogs and mist are particularly important. In areas with low levels of light pollution, the clear impact of desert dust is visible.
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Ściężor, T. (2020). The impact of clouds on the brightness of the night sky. Journal of Quantitative Spectroscopy and Radiative Transfer, in press, 106962.
Abstract: Clouds are a kind of atmospheric factor that most effectively scatters the artificial light coming from the ground. Therefore, they have the most significant impact on the brightness of the night sky. The paper analyses the influence of both the level of cloudiness, as well as the genera of clouds and altitude of its base, on amplifying of the light pollution. The impact of cloudiness on the brightness of the night sky in places with different levels of light pollution was researched. Measurements of meteorological elements were used together with clouds genera assessments. The introduction of an innovative method of identifying some genera of clouds on the base of the all-night continuous measurements of the sky's brightness allowed for a similar analysis in the absence of observational data specifying the genera of clouds.
A linear correlation between the cloudiness and the brightness of the night sky was found. The determined linear correlation parameters allow for specifying the three types of light-polluted areas, possibly related to the density of population. It was found that among the nine genera of the identified night clouds, the Altocumulus, Cirrocumulus, and Cumulonimbus ones are responsible for this correlation. No dependence of the brightness of the night sky on the clouds’ albedo was found. In case of overcast sky, there was a clear relationship between the average altitude of the individual genus of clouds and the brightness of the night sky. Most of the night sky brightness comes from the light scattered on the lowest altitude clouds genera, while the least contribution comes from the light scattered on the high-level clouds. It was also found that at the freezing temperatures, the layer of aerosols forms below the level of the genera Nimbostratus or Stratus. This layer, thickening with the decreasing temperature, additionally scatters the artificial light.
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Luginbuhl, C. B., Boley, P. A., & Davis, D. R. (2014). The impact of light source spectral power distribution on sky glow. Journal of Quantitative Spectroscopy and Radiative Transfer, 139, 21–26.
Abstract: The effect of light source spectral power distribution on the visual brightness of anthropogenic sky glow is described. Under visual adaptation levels relevant to observing the night sky, namely with dark-adapted (scotopic) vision, blue-rich (“whiteâ€) sources produce a dramatically greater sky brightness than yellow-rich sources. High correlated color temperature LEDs and metal halide sources produce a visual brightness up to 8× brighter than low-pressure sodium and 3× brighter than high-pressure sodium when matched lumen-for-lumen and observed nearby. Though the sky brightness arising from blue-rich sources decreases more strongly with distance, the visual sky glow resulting from such sources remains significantly brighter than from yellow sources out to the limits of this study at 300 km.
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