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| Author |
Hänel, A.; Posch, T.; Ribas, S.J.; Aubé, M.; Duriscoe, D.; Jechow, A.; Kollath, Z.; Lolkema, D.E.; Moore, C.; Schmidt, N.; Spoelstra, H.; Wuchterl, G.; Kyba, C.C.M. |
| Title |
Measuring night sky brightness: methods and challenges |
Type |
Journal Article |
| Year |
2018 |
Publication |
Journal of Quantitative Spectroscopy and Radiative Transfer |
Abbreviated Journal |
Journal of Quantitative Spectroscopy and Radiative Transfer |
| Volume |
205 |
Issue |
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Pages |
278-290 |
| Keywords |
skyglow |
| Abstract |
Measuring the brightness of the night sky has become an increasingly important topic in recent years, as artificial lights and their scattering by the Earthâ??s atmosphere continue spreading around the globe. Several instruments and techniques have been developed for this task. We give an overview of these, and discuss their strengths and limitations. The different quantities that can and should be derived when measuring the night sky brightness are discussed, as well as the procedures that have been and still need to be defined in this context. We conclude that in many situations, calibrated consumer digital cameras with fisheye lenses provide the best relation between ease-of-use and wealth of obtainable information on the night sky. While they do not obtain full spectral information, they are able to sample the complete sky in a period of minutes, with colour information in three bands. This is important, as given the current global changes in lamp spectra, changes in sky radiance observed only with single band devices may lead to incorrect conclusions regarding long term changes in sky brightness. The acquisition of all-sky information is desirable, as zenith-only information does not provide an adequate characterization of a site. Nevertheless, zenith-only single-band one-channel devices such as the â??Sky Quality Meterâ? continue to be a viable option for long-term studies of night sky brightness and for studies conducted from a moving platform. Accurate interpretation of such data requires some understanding of the colour composition of the sky light. We recommend supplementing long-term time series derived with such devices with periodic all-sky sampling by a calibrated camera system and calibrated luxmeters or luminance meters. |
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0022-4073 |
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LoNNe @ kyba @ |
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1731 |
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Villamizar, N.; GarcÃa-Alcazar, A.; Sánchez-Vázquez, F. J. |
| Title |
Effect of light spectrum and photoperiod on the growth, development and survival of European sea bass (Dicentrarchuslabrax) larvae |
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Journal Article |
| Year |
2009 |
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292 |
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1-2 |
Pages |
80-86 |
| Keywords |
animals; fish; light spectrum; photoperiod |
| Abstract |
This study investigates how the characteristics (spectrum and photoperiod) of artificial light affect European sea bass eggs and larvae from − 1 to 40 days post-hatching. Fertilised eggs and larvae were reared under five different light treatments: 12L:12D red light (LDR; half-peak bandwidth = 641–718 nm), 12L:12D blue light (LDB; half-peak bandwidth = 435–500 nm), 12L:12D broad-spectrum white light (LDW; 367 < λ < 1057 nm), 24L:0D broad-spectrum white light (LL) and 0L:24D (DD). The results showed that total length at day post-hatching 40 was significantly larger in larvae reared under LDB (15.4 ± 0.6 mm) and LL (15.2 ± 0.6 mm) than in larvae reared under LDR (11.7 ± 0.7 mm). Overall wet weight was highest under LDB (21.6 ± 2.02 mgr) and lowest in LDR larvae (13.6 ± 1.48 mgr). Yolk sac and oil globule absorption occurred more slowly in LDR and DD larvae, while LDB larvae developed their fin, teeth and swim bladder significantly earlier than the rest of the groups. DD larvae were unable to capture food and mortality was 100% by day post-hatching 18, while LDR larvae did not feed on rotifers, but fed on Artemia from day post-hatching 16 onwards. The best survival was obtained with the LL treatment, although significantly more problems with swim bladder development and lower jaw malformations were also identified in this group. In summary, these results highlight the key role of the light spectrum and photoperiod for European sea bass larvae, the best performance being achieved under the light conditions that best approached those of their natural aquatic environment (LDB). These findings should be considered when designing rearing protocols for larvae in aquaculture. |
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LoNNe @ schroer @ |
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1606 |
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Nasar, J.L.; Bokharaei, S. |
| Title |
Lighting modes and their effects on impressions of public squares |
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Journal Article |
| Year |
2017 |
Publication |
Journal of Environmental Psychology |
Abbreviated Journal |
Journal of Environmental Psychology |
| Volume |
49 |
Issue |
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96-105 |
| Keywords |
Psychology |
| Abstract |
Lighting may affect impressions of public places after dark. Prospect-refuge theory suggests that people would favor uniform, bright, or overhead lighting to the alternatives. The study had 363 (161 men, 202 women) adult participants. An on-line survey displayed color slides of two simulated squares, each repeated for all mixes of lighting modes (order randomized across participants). One square also varied the peripheral lighting tilt (down or out). For ratings, each participant was assigned at random to use one of twelve items for evaluation, excitement, restfulness, or behavioral intent. Because the scales had high inter-item reliability, we combined them into a composite preference scale. In agreement with P-R theory, uniform, bright, and overhead lighting received the higher scores. The peripheral lighting tilt (down or out) did not affect preference. Lighting designs might do well to offer unobstructed views of information ahead. Research could test on-site experience and different aspects of lighting. |
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0272-4944 |
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LoNNe @ kyba @ |
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1612 |
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Alamús, R.; Bará, S.; Corbera, J.; Escofet, J.; Palà , V.; Pipia, L.; Tardà, A. |
| Title |
Ground-based hyperspectral analysis of the urban nightscape |
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Journal Article |
| Year |
2017 |
Publication |
ISPRS Journal of Photogrammetry and Remote Sensing |
Abbreviated Journal |
ISPRS Journal of Photogrammetry and Remote Sensing |
| Volume |
124 |
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16-26 |
| Keywords |
Instrumentation; Remote Sensing |
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Airborne hyperspectral cameras provide the basic information to estimate the energy wasted skywards by outdoor lighting systems, as well as to locate and identify their sources. However, a complete characterization of the urban light pollution levels also requires evaluating these effects from the city dwellers standpoint, e.g. the energy waste associated to the excessive illuminance on walls and pavements, light trespass, or the luminance distributions causing potential glare, to mention but a few. On the other hand, the spectral irradiance at the entrance of the human eye is the primary input to evaluate the possible health effects associated with the exposure to artificial light at night, according to the more recent models available in the literature. In this work we demonstrate the possibility of using a hyperspectral imager (routinely used in airborne campaigns) to measure the ground-level spectral radiance of the urban nightscape and to retrieve several magnitudes of interest for light pollution studies. We also present the preliminary results from a field campaign carried out in the downtown of Barcelona. |
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0924-2716 |
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LoNNe @ kyba @ |
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1613 |
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Lee, J.G.-H.; MacGregor-Fors, I.; Yeh, P.J. |
| Title |
Sunrise in the city: disentangling drivers of the avian dawn chorus onset in urban greenspaces |
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Journal Article |
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2017 |
Publication |
Journal of Avian Biology |
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J Avian Biol |
| Volume |
48 |
Issue |
7 |
Pages |
955-964 |
| Keywords |
Animals |
| Abstract |
Urban systems are known to have a number of effects on avian diversity, density, and morphological and behavioral traits. However, no study to date has simultaneously examined the wide range of urban variables in relation to the avian dawn chorus, a complex behavioral phenomenon. Previous studies investigating adjustments of the dawn chorus onset in urban settings have mainly been confined to relationships with noise and light levels. In addition to noise and light levels, in this study we included other potentially related environmental characteristics describing vegetation structure, urban infrastructure, and human activity, all of which have been shown to be drivers of bird diversity in urban areas. We conducted dawn chorus surveys at 38 Los Angeles urban greenspaces and used a classification and regression tree analysis to identify specific urban scenarios that best explained timing differences in the dawn chorus onset. Our results show that light level was the most important determinant of the dawn chorus onset time, in which, counter-intuitively, bird communities in greenspaces with higher light levels had later onsets. In addition, noise was an important factor for the chorus onset in greenspaces with higher light levels. Although our results differ from those of previous studies, these findings highlight the importance of noise and light levels in explaining dawn chorus onset variation, indicating the need for further research in untangling this complex and ecologically important phenomenon. |
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0908-8857 |
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LoNNe @ kyba @ |
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1623 |
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