On observations of artificial light at night from ground and space

To assess the negative effects of artificial light at night, measurement data are often necessary. These can be acquired from ground or satellite-based measurements. Satellite-based observations of artificial light have an advantage of global coverage. Since the launch of the Suomi National Polar-orbiting Partnership (S-NPP) satellite, the Visible Infrared Imaging Radiometer Suite (VIIRS) Day-Night Band (DNB) provides a tool for worldwide night time remote sensing for various applications, including artificial light. We used the data in year 2015 from the VIIRS-DNB sensor to study the angular distribution of artificial light in major cities and metropoles in Europe. Despite encountering some issues, for example low overflight rate with cloud-free sky condition, we are able to investigate the angular distributions of upwelling artificial light emission for 74 regions, almost all of which emit more light near the horizon. In comparison to satellite-based observations, ground-based measurements can acquire data more frequently. An international campaign studying variations of night sky at 44 worldwide locations was conducted in 2011 and 2012, measuring the night sky using broadband radiometers, the Sky Quality Meters (SQMs), and was the first time comparing ground-based night sky measurement in a unified analysis procedure. The presence of artificial light reverses the variation pattern of sky brightness at cloudy nights. Instead of darkening of night sky by blockage of extraterrestrial light sources, clouds backscatter the artificial light emitted from ground, brighting the night sky. Comparison with daytime aerosol measurement data did not yield a consistent relationship between the aerosol content and night sky brightness for the rural site in Cabauw, the Netherlands, but found the brightening of the night sky of Madrid with increasing atmospheric aerosol load. Long-term monitoring of the night sky enables us to observe the change in skyglow pattern over a long period. Two SQMs have been set up in a suburban site and a rural site in Bremen, Germany since December 2011. The night sky of the suburban site is found to be brighter during cloudy nights and becomes darker during the course of the night, which is typical for a light-polluted location. While instrumental issues cannot be ruled out, we found a decrease of sky brightness over a span of about 4.5 years, with a stronger decreasing trend at late hours of the night. For the rural site, the local public and domestic lightings are the dominating light source, contributing to the larger skyglow in the early hours of the night. However, with domestic and public lighting switched off as the night progresses, the variation pattern of the night sky is typical for a location with less light pollution, where the overcast sky is only slightly different in brightness from clear sky. It is suspected that this trend in the change of sky brightness originates from the gradual decrease of output of the public lighting system due to aging, while the progress replacing the public lighting to light-emitting diode (LED) devices is slow. An improvement in terms of ecological impacts in the future is therefore not guaranteed

Future long-term night sky monitoring projects shall use multispectral imaging sensors when possible = Az következő éjszakai égbolt felmérések alkalmával multispektrális képi méréseket kell használni

Interest in investigation of the impact of light pollution on ecology leads to a surge of observations and measurements. This article presents the measurement of the night sky radiance in over a period of 4.5 years in the city of Bremen, Germany from two sites situated in suburban and rural areas. It was found that both sites show a decreasing trend in sky radiance. However, since no multispectral images were taken, the exact cause of the decrease cannot be determined. It is therefore recommended that future night sky measurements should be based on multispectral imaging, for example by commercial digital cameras. ----- AZ KÖVETKEZŐ ÉJSZAKAI ÉGBOLT FELMÉRÉSEK ALKALMÁVAL MULTISPEKTRÁLIS KÉPI MÉRÉSEKET KELL HASZNÁLNI A fényszennyezés ökológiai hatásának vizsgálata iránti érdeklődés megfigyelések és mérések sokaságát indította el. Ebben a cikkben egy Bremenben (Németország) elvégzett 4,5 éves égboltradiancia-méréssorozat eredményeit közöljük. A mérések két helyszínen, egy külvárosi és egy vidéki területen történtek. Mindkét helyen csökkenő tendenciát találtunk az égbolt fényességében. Azonban nem történtek multispektrális mérések, a csökkenés pontos oka nem határozható meg. Ezért javasoljuk, hogy a jövőben tervezett fényszenynyezés-felmérések esetében történjen multikulturális leképező radiometria, pl. digitális kamerák segítségével

Future long-term night sky monitoring projects shall use multispectral imaging sensors when possible

Interest in investigation of the impact of light pollution on ecology leads to a surge of observations and measurements. This article presents the measurement of the night sky radiance in over a period of 4.5 years in the city of Bremen, Germany from two sites situated in suburban and rural areas. It was found that both sites show a decreasing trend in sky radiance. However, since no multispectral images were taken, the exact cause of the decrease cannot be determined. It is therefore recommended that future night sky measurements should be based on multispectral imaging, for example by commercial digital cameras. ----- AZ KÖVETKEZŐ ÉJSZAKAI ÉGBOLT FELMÉRÉSEK ALKALMÁVAL MULTISPEKTRÁLIS KÉPI MÉRÉSEKET KELL HASZNÁLNI A fényszennyezés ökológiai hatásának vizsgálata iránti érdeklődés megfigyelések és mérések sokaságát indította el. Ebben a cikkben egy Bremenben (Németország) elvégzett 4,5 éves égboltradiancia-méréssorozat eredményeit közöljük. A mérések két helyszínen, egy külvárosi és egy vidéki területen történtek. Mindkét helyen csökkenő tendenciát találtunk az égbolt fényességében. Azonban nem történtek multispektrális mérések, a csökkenés pontos oka nem határozható meg. Ezért javasoljuk, hogy a jövőben tervezett fényszenynyezés-felmérések esetében történjen multikulturális leképező radiometria, pl. digitális kamerák segítségével

Light Pollution Survey in Hungarian National Parks = Fényszennyezés felmérés a nemzeti parkokban

We have started a light pollution survey in the Hungarian national parks. We use a mobile laboratory consisting of digital cameras and robotic panorama heads to gather high-resolution panorama imaging radiometry. The same type of cameras with fish-eye lenses are used in fix monitoring stations. Parallel to the imaging radiometry, we measure the spectral distribution of the sky radiation. The spectroradiometry provides additional calibration check on the measurements and further information on the sources of light. The mobile laboratory provides an excellent spatial resolution at a given national park while the monitoring all-sky camera stations add the possibility to detect temporal changes in night sky quality. We developed new SI traceable metrics for the measurement of night sky quality. The RGB colour channels of the camera provide an optimal way to obtain multispectral radiance information. The selected metric is the band-averaged spectral radiance. Besides, we use a colour enhancement technique to find traces of different sources of night sky radiance. In the near future, we expect a large amount of high-quality data from the Hungarian national parks, which provide an outstanding possibility in light pollution related and atmospheric research. In the paper, we present the first results of the sky quality survey. ----- FÉNYSZENNYEZÉS FELMÉRÉS A NEMZETI PARKOKBAN Fényszennyezés-felmérést kezdtünk a magyarországi nemzeti parkokban. A vizsgálathoz digitális kamerákból és automata panorámafejekből álló hordozható laboratóriumot használunk, amellyel lehetőség van a nagy felbontású panorámaleképező radiometria végzésére. Ugyanilyen típusú kamerákat és halszemoptikákat állandó telepítésű mérőállomásokon is használunk. A leképező radiometriával párhuzamosan az égbolt fénylésének spektrális eloszlását is mérjük. A spektroradiometria járulékos kalibrációs információt szolgáltat a mérésekhez, ezen kívül segít a lehetséges források megkülönböztetésében is. A hordozható laboratórium megfelelő térbeli felbontást szolgáltat a nemzeti parkokban, míg az állandó teljeségbolt-mérőállomások biztosítják azt az időbeli felbontást, amellyel az égboltminőség változásait érzékelhetjük. Kidolgoztunk egy SI-egységekre visszavezethető metrikát az égboltminőség méréséhez, a kiválasztott metrika a sávátlagolt spektrális sugársűrűség. Ezen kívül egy színkiemeléses eljárást is alkalmazunk, amellyel az égbolt fénylésének különböző forrásainak a jeleit detektálhatjuk. A közeljövőben a magyarországi nemzeti parkokból nagy mennyiségű, jó minőségű adatra számíthatunk, ami kiváló lehetőséget ad a fényszennyezéssel kapcsolatos és légkörfizikai jellegű kutatá- sokhoz. A jelen cikkben bemutatjuk az égboltminőség-felmérés első eredményeit

Light Pollution Survey in Hungarian National Parks

We have started a light pollution survey in the Hungarian national parks. We use a mobile laboratory consisting of digital cameras and robotic panorama heads to gather high-resolution panorama imaging radiometry. The same type of cameras with fish-eye lenses are used in fix monitoring stations. Parallel to the imaging radiometry, we measure the spectral distribution of the sky radiation. The spectroradiometry provides additional calibration check on the measurements and further information on the sources of light. The mobile laboratory provides an excellent spatial resolution at a given national park while the monitoring all-sky camera stations add the possibility to detect temporal changes in night sky quality. We developed new SI traceable metrics for the measurement of night sky quality. The RGB colour channels of the camera provide an optimal way to obtain multispectral radiance information. The selected metric is the band-averaged spectral radiance. Besides, we use a colour enhancement technique to find traces of different sources of night sky radiance. In the near future, we expect a large amount of high-quality data from the Hungarian national parks, which provide an outstanding possibility in light pollution related and atmospheric research. In the paper, we present the first results of the sky quality survey. ----- FÉNYSZENNYEZÉS FELMÉRÉS A NEMZETI PARKOKBAN Fényszennyezés-felmérést kezdtünk a magyarországi nemzeti parkokban. A vizsgálathoz digitális kamerákból és automata panorámafejekből álló hordozható laboratóriumot használunk, amellyel lehetőség van a nagy felbontású panorámaleképező radiometria végzésére. Ugyanilyen típusú kamerákat és halszemoptikákat állandó telepítésű mérőállomásokon is használunk. A leképező radiometriával párhuzamosan az égbolt fénylésének spektrális eloszlását is mérjük. A spektroradiometria járulékos kalibrációs információt szolgáltat a mérésekhez, ezen kívül segít a lehetséges források megkülönböztetésében is. A hordozható laboratórium megfelelő térbeli felbontást szolgáltat a nemzeti parkokban, míg az állandó teljeségbolt-mérőállomások biztosítják azt az időbeli felbontást, amellyel az égboltminőség változásait érzékelhetjük. Kidolgoztunk egy SI-egységekre visszavezethető metrikát az égboltminőség méréséhez, a kiválasztott metrika a sávátlagolt spektrális sugársűrűség. Ezen kívül egy színkiemeléses eljárást is alkalmazunk, amellyel az égbolt fénylésének különböző forrásainak a jeleit detektálhatjuk. A közeljövőben a magyarországi nemzeti parkokból nagy mennyiségű, jó minőségű adatra számíthatunk, ami kiváló lehetőséget ad a fényszennyezéssel kapcsolatos és légkörfizikai jellegű kutatá- sokhoz. A jelen cikkben bemutatjuk az égboltminőség-felmérés első eredményeit

Multiple Angle Observations Would Benefit Visible Band Remote Sensing Using Night Lights

The spatial and angular emission patterns of artificial and natural light emitted, scattered, and reflected from the Earth at night are far more complex than those for scattered and reflected solar radiation during daytime. In this commentary, we use examples to show that there is additional information contained in the angular distribution of emitted light. We argue that this information could be used to improve existing remote sensing retrievals based on night lights, and in some cases could make entirely new remote sensing analyses possible. This work will be challenging, so we hope this article will encourage researchers and funding agencies to pursue further study of how multi‐angle views can be analyzed or acquired

Worldwide variations in artificial skyglow

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

Commentary: Multiple Angle Observations Would Benefit Visible Band Remote Sensing using Night Lights

The spatial and angular emission patterns of artificial and natural light emitted, scattered, and reflected from the Earth at night are far more complex than those for scattered and reflected solar radiation during daytime. In this commentary, we use examples to show that there is additional information contained in the angular distribution of emitted light. We argue that this information could be used to improve existing remote sensing retrievals based on night lights, and in some cases could make entirely new remote sensing analyses possible. This work will be challenging, so we hope this article will encourage researchers and funding agencies to pursue further study of how multi-angle views can be analyzed or acquired

Boden- und satellitengestützte Beobachtung von künstlichen Licht bei Nacht

To assess the negative effects of artificial light at night, measurement data are often necessary. These can be acquired from ground or satellite-based measurements. Satellite-based observations of artificial light have an advantage of global coverage. Since the launch of the Suomi National Polar-orbiting Partnership (S-NPP) satellite, the Visible Infrared Imaging Radiometer Suite (VIIRS) Day-Night Band (DNB) provides a tool for worldwide night time remote sensing for various applications, including artificial light. We used the data in year 2015 from the VIIRS-DNB sensor to study the angular distribution of artificial light in major cities and metropoles in Europe. Despite encountering some issues, for example low overflight rate with cloud-free sky condition, we are able to investigate the angular distributions of upwelling artificial light emission for 74 regions, almost all of which emit more light near the horizon. In comparison to satellite-based observations, ground-based measurements can acquire data more frequently. An international campaign studying variations of night sky at 44 worldwide locations was conducted in 2011 and 2012, measuring the night sky using broadband radiometers, the Sky Quality Meters (SQMs), and was the first time comparing ground-based night sky measurement in a unified analysis procedure. The presence of artificial light reverses the variation pattern of sky brightness at cloudy nights. Instead of darkening of night sky by blockage of extraterrestrial light sources, clouds backscatter the artificial light emitted from ground, brighting the night sky. Comparison with daytime aerosol measurement data did not yield a consistent relationship between the aerosol content and night sky brightness for the rural site in Cabauw, the Netherlands, but found the brightening of the night sky of Madrid with increasing atmospheric aerosol load. Long-term monitoring of the night sky enables us to observe the change in skyglow pattern over a long period. Two SQMs have been set up in a suburban site and a rural site in Bremen, Germany since December 2011. The night sky of the suburban site is found to be brighter during cloudy nights and becomes darker during the course of the night, which is typical for a light-polluted location. While instrumental issues cannot be ruled out, we found a decrease of sky brightness over a span of about 4.5 years, with a stronger decreasing trend at late hours of the night. For the rural site, the local public and domestic lightings are the dominating light source, contributing to the larger skyglow in the early hours of the night. However, with domestic and public lighting switched off as the night progresses, the variation pattern of the night sky is typical for a location with less light pollution, where the overcast sky is only slightly different in brightness from clear sky. It is suspected that this trend in the change of sky brightness originates from the gradual decrease of output of the public lighting system due to aging, while the progress replacing the public lighting to light-emitting diode (LED) devices is slow. An improvement in terms of ecological impacts in the future is therefore not guaranteed

Evaluation of Global Differential Gene and Protein Expression in Primary Pterygium: S100A8 and S100A9 as Possible Drivers of a Signaling Network

<div><p>Purpose</p><p>Pterygium is a wing shaped fibrovascular growth on the ocular surface, characterized by fibrosis, angiogenesis, extracellular matrix remodeling, and inflammatory infiltrates. Epidemiologic studies have linked pterygium formation to various chronic inflammatory conditions, such as ultraviolet radiation, sawdust exposure, and dry eye disease. The purpose of this study is to identify proteins that are differentially expressed in primary pterygium by using a combination of gene microarray and proteomic platforms.</p><p>Methods</p><p>Paired pterygium and uninvolved conjunctiva tissues of four patients were evaluated for differences in global gene transcript levels using a genechip microarray. Proteins extracted from another four pairs of tissues were quantified by iTRAQ approach. Western blot and immunofluorescent staining on additional patients were used to validate dysregulated protein expression obtained from microarray and proteomics data. In addition, primary conjunctival fibroblasts were treated with recombinant S100A8, S100A9 or both. Transcript level changes of a panel of potential target genes were evaluated by real time-PCR.</p><p>Results</p><p>The following were up-regulated at both protein and transcript levels S100 A8 and A9, aldehyde dehydrogenase 3 family, member1 (ALDH3A1) and vimentin (VIM). Conversely, serpin peptidase inhibitor clade A member 1 (SERPINA1) and transferrin (TF) were down-regulated. Upon adding S100A8, S100A9 or both, the inflammatory chemokine CXCL1, matrix proteins vimentin, biglycan, and gelsolin, as well as annexin-A2, thymosin-β4, chymase (CMA1), member of Ras oncogene family RAB10 and SERPINA1 were found to be up-regulated.</p><p>Conclusions</p><p>We identified 3 up-regulated and 2 down-regulated proteins by using a stringent approach comparing microarray and proteomic data. On stimulating cells with S100A8/9, a repertoire of key genes found to be up-regulated in pterygium tissue, were induced in these cells. S100A8/9 may be an upstream trigger for inflammation and other disease pathways in pterygium.</p></div