scholarly journals Worldwide variations in artificial skyglow

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Christopher C. M. Kyba ◽  
Kai Pong Tong ◽  
Jonathan Bennie ◽  
Ignacio Birriel ◽  
Jennifer J. Birriel ◽  
...  
Keyword(s):  
Monitoring Program ◽  
Artificial Light ◽  
Clear Sky ◽  
International Monitoring ◽  
Sky Brightness ◽  
Ground Truthing ◽  
Study Sites ◽  
Night Sky Brightness ◽  
Key Questions

Abstract Despite constituting a widespread and significant environmental change, understanding of artificial nighttime skyglow is extremely limited. Until now, published monitoring studies have been local or regional in scope and typically of short duration. In this first major international compilation of monitoring data we answer several key questions about skyglow properties. Skyglow is observed to vary over four orders of magnitude, a range hundreds of times larger than was the case before artificial light. Nearly all of the study sites were polluted by artificial light. A non-linear relationship is observed between the sky brightness on clear and overcast nights, with a change in behavior near the rural to urban landuse transition. Overcast skies ranged from a third darker to almost 18 times brighter than clear. Clear sky radiances estimated by the World Atlas of Artificial Night Sky Brightness were found to be overestimated by ~25%; our dataset will play an important role in the calibration and ground truthing of future skyglow models. Most of the brightly lit sites darkened as the night progressed, typically by ~5% per hour. The great variation in skyglow radiance observed from site-to-site and with changing meteorological conditions underlines the need for a long-term international monitoring program.

scholarly journals Evidence That Reduced Air and Road Traffic Decreased Artificial Night-Time Skyglow during COVID-19 Lockdown in Berlin, Germany

2020 ◽  
Vol 12 (20) ◽  
pp. 3412
Author(s):  
Andreas Jechow ◽  
Franz Hölker
Keyword(s):  
Road Traffic ◽  
Satellite Image ◽  
Color Temperature ◽  
Light Pollution ◽  
Artificial Light ◽  
Night Time ◽  
Sky Brightness ◽  
Night Sky ◽  
The Impact ◽  
Night Sky Brightness

Artificial skyglow, the brightening of the night sky by artificial light at night that is scattered back to Earth within the atmosphere, is detrimental to astronomical observations and has an impact on ecosystems as a form of light pollution. In this work, we investigated the impact of the lockdown caused by the COVID-19 pandemic on the urban skyglow of Berlin, Germany. We compared night sky brightness and correlated color temperature (CCT) measurements obtained with all-sky cameras during the COVID-19 lockdown in March 2020 with data from March 2017. Under normal conditions, we expected an increase in night sky brightness (or skyglow, respectively) and CCT because of the transition to LED. This is supported by a measured CCT shift to slightly higher values and a time series analysis of night-time light satellite data showing an increase in artificial light emission in Berlin. However, contrary to this observation, we measured a decrease in artificial skyglow at zenith by 20% at the city center and by more than 50% at 58 km distance from the center during the lockdown. We assume that the main cause for the reduction of artificial skyglow originates from improved air quality due to less air and road traffic, which is supported by statistical data and satellite image analysis. To our knowledge, this is the first reported impact of COVID-19 on artificial skyglow and we conclude that air pollution should shift more into the focus of light pollution research.

scholarly journals Sky brightness measurements for different environmental conditions by the example of St. Petersburg

2018 ◽  
Vol 43 ◽  
pp. 01010
Author(s):  
Svetlana Kolgushkina
Keyword(s):  
Environmental Conditions ◽  
Light Emission ◽  
Anthropogenic Factors ◽  
City Center ◽  
Clear Sky ◽  
Series Of Experiments ◽  
Sky Brightness ◽  
Sky Conditions ◽  
The City ◽  
Night Sky Brightness

St. Petersburg is unique place in Russia with an environmental phenomenon called “white nights” during summertime: sky brightness levels are influenced mostly by environmental conditions. Sky conditions during the winter are opposite: light emission is mostly caused by the anthropogenic factors. A series of experiments were conducted between May and December 2017 using a Sky Quality Meter (SQM-LU-DL), a night sky brightness photometer, to understand the differences between sky brightness levels for different environmental conditions and seasonal variations. Sky brightness distinction between the city center and 20 km distance were estimated for clear sky conditions.

scholarly journals Direct assessment of the sensitivity drift of SQM sensors installed outdoors

2021 ◽  
Vol 23 (1) ◽  
pp. 1-6
Author(s):  
Salvador Bará ◽  
Enric Marco ◽  
Salvador J. Ribas ◽  
Manuel Garcia Gil ◽  
Alejandro Sánchez de Miguel ◽  
...  
Keyword(s):  
Average Rate ◽  
Short Note ◽  
Mitigation Measures ◽  
Monitoring Networks ◽  
Large Variability ◽  
Global Irradiation ◽  
Sky Brightness ◽  
Night Sky ◽  
Night Sky Brightness

Long-term monitoring of the evolution of the artificial night sky brightness is a key tool for developing science-informed public policies and assessing the efficacy of light pollution mitigation measures. Detecting the underlying artificial brightness trend is a challenging task, since the typical night sky brightness signal shows a large variability with characteristic time scales ranging from seconds to years. In order to effectively isolate the weak signature of the effect of interest, determining the potential long term drifts of the radiance sensing systems is crucial. If these drifts can be adequately characterized, the raw measurements could be easily corrected for them and transformed to a consistent scale. In this short note we report on the progressive darkening of the signal recorded by SQM detectors belonging to several monitoring networks, permanently installed outdoors for periods ranging from several months to several years. The sensitivity drifts were estimated by means of parallel measurements made at the beginning and at the end of the evaluation periods using reference detectors of the same kind that were little or no exposed to weathering in the intervening time. Our preliminary results suggest that SQM detectors installed outdoors steadily increase their readings at an average rate of +0.034 magSQM/arcsec2 per MWh/m2 of exposure to solar horizontal global irradiation, that for our locations translates into approximately +0.05 to +0.06 magSQM/arcsec2 per year.

Paleolimnological perspectives on the shifting geographic template of permafrost landscapes and its implications for Arctic freshwater biodiversity

2022 ◽  
Author(s):  
Jennifer Korosi ◽  
Kristen Coleman ◽  
Grace N Hoskin ◽  
Amanda Little ◽  
Emily Stewart ◽  
...  
Keyword(s):  
Monitoring Program ◽  
Indigenous Communities ◽  
Freshwater Biodiversity ◽  
Thermokarst Lake ◽  
Geographic Context ◽  
Warming Climate ◽  
Thawing Permafrost ◽  
Study Sites ◽  
Long Timescales

Geographic context matters when trying to understand how permafrost thaw impacts northern freshwater biodiversity in a warming climate. Most risk to freshwater from thawing permafrost is associated with abrupt thaw processes known as thermokarst. Lake sediments can provide a record of thermokarst landscape development and associated biogeochemical and biodiversity trends over long timescales, providing a tool to link thermokarst geomorphology with freshwater biodiversity. We describe how paleolimnology, with its inherent emphasis on long-term perspectives, can characterize the shifting geographic template of warming thermokarst landscapes and its implications for biodiversity. We suggest aligning thermokarst lake paleolimnological research with hypothesis-testing frameworks used by permafrost hydrologists and biogeochemists and by the Freshwater Circumpolar Biodiversity Monitoring Program, and advocate for knowledge co-production with northern Indigenous communities. Lastly, we stress the importance of considering geographic context in the choice of study sites to ensure that diverse thermokarst landscapes are represented (especially those most vulnerable to warming) and that the fine-scale differences in limnological settings that influence ecosystem response to thermokarst stressors are accounted for.

scholarly journals Light Pollution Monitoring and Sky Colours

2020 ◽  
Vol 6 (10) ◽  
pp. 104 ◽  
Author(s):  
Zoltán Kolláth ◽  
Dénes Száz ◽  
Kornél Kolláth ◽  
Kai Pong Tong
Keyword(s):  
Nature Conservation ◽  
Digital Camera ◽  
Pollution Monitoring ◽  
Light Pollution ◽  
Term Evolution ◽  
Sky Brightness ◽  
Night Sky ◽  
Artificial Changes ◽  
Night Sky Brightness

The measurement of night sky quality has become an important task in nature conservation. The primary device used for this task can be a calibrated digital camera. In addition, colour information can be derived from sky photography. In this paper, we provide a test on a concept to gather information about the possible sources of night sky brightness based on digital camera images. This method helps to understand changes in night sky quality due to natural and artificial changes in the environment. We demonstrate that a well-defined colour–colour diagram can differentiate between the different natural and artificial sources of night sky radiance. The colour information can be essential when interpreting long-term evolution of light pollution measurements.

scholarly journals Monitoring Long-Term Trends in the Anthropogenic Night Sky Brightness

2019 ◽  
Vol 11 (11) ◽  
pp. 3070 ◽  
Author(s):  
Salvador Bará ◽  
Raul C. Lima ◽  
Jaime Zamorano
Keyword(s):  
Dynamic Range ◽  
Average Rate ◽  
Monitoring Network ◽  
High Dynamic Range ◽  
Atmospheric Conditions ◽  
Long Term Trends ◽  
Sky Brightness ◽  
Night Sky ◽  
Night Sky Brightness

Monitoring long-term trends in the evolution of the anthropogenic night sky brightness is a demanding task due to the high dynamic range of the artificial and natural light emissions and the high variability of the atmospheric conditions that determine the amount of light scattered in the direction of the observer. In this paper, we analyze the use of a statistical indicator, the mFWHM, to assess the night sky brightness changes over periods of time larger than one year. The mFWHM is formally defined as the average value of the recorded magnitudes contained within the full width at half-maximum region of the histogram peak corresponding to the scattering of artificial light under clear skies in the conditions of a moonless astronomical night (sun below −18°, and moon below −5°). We apply this indicator to the measurements acquired by the 14 SQM detectors of the Galician Night Sky Brightness Monitoring Network during the period 2015–2018. Overall, the available data suggest that the zenithal readings in the Sky Quality Meter (SQM) device-specific photometric band tended to increase during this period of time at an average rate of +0.09 magSQM/arcsec2 per year.

scholarly journals Estimating the relative contribution of streetlights, vehicles, and residential lighting to the urban night sky brightness

2018 ◽  
Vol 51 (7) ◽  
pp. 1092-1107 ◽  
Author(s):  
S Bará ◽  
Á Rodríguez-Arós ◽  
M Pérez ◽  
B Tosar ◽  
RC Lima ◽  
...  
Keyword(s):  
Time Course ◽  
Residential Buildings ◽  
Artificial Light ◽  
Light Sources ◽  
Wide Field ◽  
Atmospheric Conditions ◽  
Least Squares Fit ◽  
Sky Brightness ◽  
Night Sky ◽  
Night Sky Brightness

Under stable atmospheric conditions the brightness of the urban sky varies throughout the night following the time course of the anthropogenic emissions of light. Different types of artificial light sources (e.g. streetlights, residential, and vehicle lights) have specific time signatures, and this feature makes it possible to estimate the amount of brightness contributed by each of them. Our approach is based on transforming the time representation of the zenithal night sky brightness into a modal expansion in terms of the time signatures of the different sources of light. The modal coefficients, and hence the absolute and relative contributions of each type of source, can be estimated by means of a linear least squares fit. A practical method for determining the time signatures of different contributing sources is also described, based on wide-field time-lapse photometry of the urban nightscape. Our preliminary results suggest that, besides the dominant streetlight contribution, artificial light leaking out of the windows of residential buildings may account for a significant share of the time-varying part of the zenithal night sky brightness at the measurement locations, whilst the contribution of the vehicle lights seems to be significantly smaller.

Living Environmental Laboratory for Lighting — A comprehensive study of interactions of artificial lighting and wildlifes

2020 ◽  
Author(s):  
Kai Pong Tong ◽  
Zoltán Kolláth
Keyword(s):  
National Parks ◽  
Light Pollution ◽  
Artificial Light ◽  
Human Beings ◽  
Pollution Research ◽  
Environmental Laboratory ◽  
Sky Brightness ◽  
Night Sky ◽  
The Impact ◽  
Night Sky Brightness

<p>Artificial light at night (ALAN) has become a major concern in recent years due to its impact on the health of human beings and the ecosystems. As a result, there is a surge of light pollution research not only on night sky brightness, but also on assessments of impacts on both ecology and society.</p><p>We have set up an interdisciplinary project in Hungary since September 2017, to not only study the impacts of change in lighting technology on patterns of ALAN (with emphasis on the areas within and around national parks in Hungary), but also facilitate national and international cooperations in light pollution research. We refer to this project as Living Environmental Laboratory for Lighting (LELL). Specifically, the project covers the following areas:</p><p><strong>1. Development of new techniques for night sky radiometry and spectrometry</strong><br>We are developing techniques for night sky multispectral measurements using commercially available cameras with interchangeable lens, calibrated by high sensitivity spectroradiometer, in order to quantify night sky condition and identify sources of artificial light at high resolution not achieveable by systems based on panchromatic sensors or fisheye lenses. In addition, we will compare the results from our ground-based measurements with satellite-based observations.</p><p><strong>2. Modeling of night sky patterns in national parks of Hungary</strong><br>We have developed a Monte-Carlo method of modeling light pollution, which can also be used for investigating effects of aerosols and clouds on the propagation of artificial light.</p><p><strong>3. Impact assessments of ALAN through measurements</strong><br>The public lighting was remodeled to LED-based systems in two areas close to national parks, one of which in the Zselic region in Southwestern Hungary, and another in Bükk in Northern Hungary. Using the techniques above, we are monitoring the change in night sky brightness and color, as well as the impact on flora and fauna.</p><p><strong>4. Recommendations on future assessments and mitigations of</strong> <strong>light pollution</strong><br>With our experience gain within the duration of this project, we will inform the light pollution research community of standardizing methodologies for monitoring light pollution, as well as giving recommendations for managing public lighting assets to reduce the impacts of light pollution.</p><p><br><strong>Acknowledgement</strong><br>This project is supported by the European Union and co-financed by the<br>European Social Fund (Grant no. EFOP–3.6.2–16–201–00014: Development of<br>international research environment for light pollution studies)</p>

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