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Petržala, J. (2018). Feasibility of inverse problem solution for determination of city emission function from night sky radiance measurements. Journal of Quantitative Spectroscopy and Radiative Transfer, 213, 86–94.
Abstract: The knowledge of the emission function of a city is crucial for simulation of sky glow in its vicinity. The indirect methods to achieve this function from radiances measured over a part of the sky have been recently developed. In principle, such methods represent an ill-posed inverse problem. This paper deals with the theoretical feasibility study of various approaches to solving of given inverse problem. Particularly, it means testing of fitness of various stabilizing functionals within the Tikhonov’s regularization. Further, the L-curve and generalized cross validation methods were investigated as indicators of an optimal regularization parameter. At first, we created the theoretical model for calculation of a sky spectral radiance in the form of a functional of an emission spectral radiance. Consequently, all the mentioned approaches were examined in numerical experiments with synthetical data generated for the fictitious city and loaded by random errors. The results demonstrate that the second order Tikhonov’s regularization method together with regularization parameter choice by the L-curve maximum curvature criterion provide solutions which are in good agreement with the supposed model emission functions.
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Charlier, B. (2018). “You Know the Pyrenees by Day – Come See Them by Night...” Reflections on in visu Artialisation of Nocturnal Skyscapes in the Pyrenees. rga, 106(1).
Abstract: “Nocturnal skyscapes. You know the Pyrenees by day – come see them by night... ”: thus the title of an exhibition of photographs set up in 2012 by the Pays de Lourdes et des Vallées des Gaves (Hautes-Pyrénées département) to help raise public awareness about the project for the Pic du Midi International Dark Sky Reserve (IDSR), mainly among the local population and stakeholders in the areas concerned.
Although its evocative title might suggest otherwise, this is rather more than an exhibition on the iconic sites of the Pyrenees seen at night. What it seems to do is to bring out new landscapes that are not just “mountainscapes at night”, or simply night-time versions of landscapes seen by day.
The night skies that characterise these landscapes therefore represent an new category, they need to be considered in their entirety as conveying a meaning that encompasses all that is both construed and material in our relationships with landscape. As in many areas with similar projects either in place (North America, Europe) or emerging (the Cévennes and Mercantour national parks in France, for example), the creation of the Pic du Midi IDSR will have helped to bring a new kind of “landscape object” (Besse, 2009) into being in the Pyrenean region.
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Kyba, C. C. M. (2018). Is light pollution getting better or worse? Nat Astron, 2(4), 267–269.
Abstract: Awareness of light pollution is spreading, but with changing lighting technologies, emissions are shifting to wavelengths our current measuring devices cannot assess well. Community involvement is essential to evaluate changes in sky brightness.
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Garcia-Saenz, A., Sánchez de Miguel, A., Espinosa, A., Valentin, A., Aragonés, N., Llorca, J., et al. (2018). Evaluating the Association between Artificial Light-at-Night Exposure and Breast and Prostate Cancer Risk in Spain (MCC-Spain Study). Environmental Health Perspectives, 126(04).
Abstract: Background: Night shift work, exposure to light at night (ALAN) and circadian disruption may increase the risk of hormone-dependent cancers.
Objectives: We evaluated the association of exposure to ALAN during sleeping time with breast and prostate cancer in a population based multicase–control study (MCC-Spain), among subjects who had never worked at night. We evaluated chronotype, a characteristic that may relate to adaptation to light at night.
Methods: We enrolled 1,219 breast cancer cases, 1,385 female controls, 623 prostate cancer cases, and 879 male controls from 11 Spanish regions in 2008–2013. Indoor ALAN information was obtained through questionnaires. Outdoor ALAN was analyzed using images from the International Space Station (ISS) available for Barcelona and Madrid for 2012–2013, including data of remotely sensed upward light intensity and blue light spectrum information for each geocoded longest residence of each MCC-Spain subject.
Results: Among Barcelona and Madrid participants with information on both indoor and outdoor ALAN, exposure to outdoor ALAN in the blue light spectrum was associated with breast cancer [adjusted odds ratio (OR) for highest vs. lowest tertile, OR=1.47; 95% CI: 1.00, 2.17] and prostate cancer (OR=2.05; 95% CI: 1.38, 3.03). In contrast, those exposed to the highest versus lowest intensity of outdoor ALAN were more likely to be controls than cases, particularly for prostate cancer. Compared with those who reported sleeping in total darkness, men who slept in “quite illuminated” bedrooms had a higher risk of prostate cancer (OR=2.79; 95% CI: 1.55, 5.04), whereas women had a slightly lower risk of breast cancer (OR=0.77; 95% CI: 0.39, 1.51).
Conclusion: Both prostate and breast cancer were associated with high estimated exposure to outdoor ALAN in the blue-enriched light spectrum.
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Duriscoe, D. M., Anderson, S. J., Luginbuhl, C. B., & Baugh, K. E. (2018). A simplified model of all-sky artificial sky glow derived from VIIRS Day/Night band data. Journal of Quantitative Spectroscopy and Radiative Transfer, 214, 133–145.
Abstract: We present a simplified method using geographic analysis tools to predict the average artificial luminance over the hemisphere of the night sky, expressed as a ratio to the natural condition. The VIIRS Day/Night Band upward radiance data from the Suomi NPP orbiting satellite was used for input to the model. The method is based upon a relation between sky glow brightness and the distance from the observer to the source of upward radiance. This relationship was developed using a Garstang radiative transfer model with Day/Night Band data as input, then refined and calibrated with ground-based all-sky V-band photometric data taken under cloudless and low atmospheric aerosol conditions. An excellent correlation was found between observed sky quality and the predicted values from the remotely sensed data. Thematic maps of large regions of the earth showing predicted artificial V-band sky brightness may be quickly generated with modest computing resources. We have found a fast and accurate method based on previous work to model all-sky quality. We provide limitations to this method. The proposed model meets requirements needed by decision makers and land managers of an easy to interpret and understand metric of sky quality.
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