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Obsolete: Machine translation of the Variación espacial, temporal y espectral de la contaminación lumínica y sus fuentes: Metodología y resultados
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Please No not use this versions: use the draft of the proper translation: https://www.researchgate.net/publication/304212932_Spatial_Temporal_and_Spectral_Variation_of_Light_pollution_and_its_sources_Methodology_and_Resources
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... The main sources of remote-sensed nighttime lighting data have been colourblind (i.e. single broad band; Elvidge et al., 1999;Liao et al., 2013;Levin et al., 2014;Kyba et al., 2014), and hyperspectral and multispectral data have only been available for a few specific locations photographed as a part of research campaigns (Birmingham - Hale et al., 2013, Berlin -Kuechly et al., 2012Sánchez de Miguel, 2015, Madrid -Sánchez de Miguel, 2015, Catalonia -Tardà et al., 2011, Las Vegas -Metcalf, 2012, Upper Austria -Ruhtz et al., 2015. There are some new cubesat missions currently exploring the possibilities of nocturnal remote sensing (Walczak et al., 2017;Zheng et al., 2018), in the future there is likely to be access to hyperspectral data from satellites like TEMPO (Carr et al., 2017) and potentially also from Sentinel 4 or 5b, and there have been calls for a dedicated "nightsat" satellite (Elvidge et al., 2007(Elvidge et al., , 2010. ...
... Between 2003 and 2010, a total of 35,995 nighttime images were taken, with a further 423,520 between 2011 and November 2014. Of these, at least 30,000 images are of cities at night Sánchez de Miguel, 2015). In this paper, we first present a method to classify outdoor lighting types from ISS imagery, using colour-colour diagrams (which can also be used for similar images obtained from remote sensing aerial or ground based platforms). ...
... Neither does the raw data show the real ratios between the different channels. In order to resolve these discrepancies we applied standard procedures of decodification of the raw data, linearity correction of the sensor and vignetting correction of the lens (Sánchez de Miguel, 2015). Furthermore, corrections of the relative intensity between channels have been applied. ...
Sensors on remote sensing satellites have provided useful tools for evaluation of the environmental impacts of nighttime artificial light pollution. However, due to their panchromatic nature, the data available from these sensors (VIIRS/DNB and DMSP/OLS) has a limited capacity accurately to assess this impact. Moreover, in some cases, recorded variations can be misleading. Until new satellite platforms and sensors are available, only nighttime images taken with DSLR cameras from the International Space Station (ISS), airplanes, balloons or other such platforms can provide the required information. Here we describe a theoretical approach using colour-colour diagrams to analyse images taken by astronauts on the ISS to estimate spatial and temporal variation in the spectrum of artificial lighting emissions. We then evaluate how this information can be used to determine effects on some key environmental indices: photopic vision, the Melatonin Suppression Index, the Star Light Index, the Induced Photosynthesis Index, production of NO 2-NO radicals, energy efficiency and CO 2 emissions, and Correlated Colour Temperature. Finally, we use the city of Milan as a worked example of the approach.
... Portnov, 2017Portnov, , 2018Xu et al., 2018;Levin et al., 2020). Indeed, the only research work we are aware of that made some attempt to address issues of calibration is that of So (2014), which used a dark subtraction, and those in which the current team has been involved (Zamorano et al., 2011;Sánchez de Miguel, 2015;Garcia-Saenz et al., 2018Hale and Arlettaz, 2019;Bará, 2020;Pauwels et al., 2019;Sánchez de Miguel et al., 2019, 2020. The effects of this lack of calibration can be very different from study to study and need to be considered carefully. ...
... A pure ideal CCD/CMOS RAW file coming from an ideal sensor will have three components: (i) the signal itself, (ii) an artificial signal (bias) included on the sensor to avoid negative values in the process of digitalization, and (iii) Gaussian noise plus an additive constant (dark current) arising from the sensor's sensitivity to heat. On our reference camera, the Nikon D3s, and all subsequent versions except the Nikon D5, a complex hardware treatment is applied to the signal (Koyama and Jiang, 2011;Sánchez de Miguel, 2015). This treatment means that we do not need to do any bias or dark correction in these cases, but noise effects need to be controlled. ...
Nighttime images taken with DSLR cameras from the International Space Station (ISS) can provide valuable information on the spatial and temporal variation of artificial nighttime lighting on Earth. In particular, this is the only source of historical and current visible multispectral data across the world (DMSP/OLS and SNPP/VIIRS-DNB data are panchromatic and multispectral in the infrared but not at visible wavelengths). The ISS images require substantial processing and proper calibration to exploit intensities and ratios from the RGB channels. Here we describe the different calibration steps, addressing in turn Decodification, Linearity correction (ISO dependent), Flat field/Vignetting, Spectral characterization of the channels, Astrometric calibration/georeferencing, Photometric calibration (stars)/Radiometric correction (settings correction - by exposure time, ISO, lens transmittance, etc) and Transmittance correction (window transmittance, atmospheric correction). We provide an example of the application of this processing method to an image of Spain.
... cars, private outdoor lighting, commercial lighting and indoor lighting), as most of the lamps used for ornamental lighting and private outdoor lighting are metal halide lamps, or have been replaced by LED that produce white or blue-white light with a significant emission in blue, so that once they are switched off the records of the photometer with B filter are significantly higher due to the lower brightness in this band (see Figure 6). This effect has been documented before in many other cities, like Berlin or Madrid [33][34][35]. [12]. Location thanks to the Cities at Night project [36]. ...
’Lockdown’ periods in response to COVID-19 have provided a unique opportunity to study the impacts of economic activity on environmental pollution (e.g., NO2, aerosols, noise, light). The effects on NO2 and aerosols have been very noticeable and readily demonstrated, but that on light pollution has proven challenging to determine. The main reason for this difficulty is that the primary source of nighttime satellite imagery of the earth is the SNPP-VIIRS/DNB instrument, which acquires data late at night after most human nocturnal activity has already occurred and much associated lighting has been turned off. Here, to analyze the effect of lockdown on urban light emissions, we use ground and satellite data for Granada, Spain, during the COVID-19 induced confinement of the city’s population from 14 March until 31 May 2020. We find a clear decrease in light pollution due both to a decrease in light emissions from the city and to a decrease in anthropogenic aerosol content in the atmosphere which resulted in less light being scattered. A clear correlation between the abundance of PM10 particles and sky brightness is observed, such that the more polluted the atmosphere the brighter the urban night sky. An empirical expression is determined that relates PM10 particle abundance and sky brightness at three different wavelength bands.
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.
Plain Language Summary
When satellites take images of Earth, they usually do so from directly above (or as close to it as is reasonably possible). In this comment, we show that for studies that use imagery of Earth at night, it may be beneficial to take several images of the same area at different angles within a short period of time. For example, different types of lights shine in different directions (street lights usually shine down, while video advertisements shine sideways), and tall buildings can block the view of a street from some viewing angles. Additionally, since views from different directions pass through different amounts of air, imagery at multiple angles could be used to obtain information about Earth's atmosphere, and measure artificial and natural night sky brightness. The main point of the paper is to encourage researchers, funding agencies, and space agencies to think about what new possibilities could be achieved in the future with views of night lights at different angles.
ABSTRACT: Since the release of the digital archives of Defense Meteorological Satellite Program Operational Line Scanner (DMSP/OLS) nighttime light data in 1992, a variety of datasets based on this database have been produced and applied to monitor and analyze human activities and natural phenomena. However, differences among these datasets and how they have been applied may potentially confuse researchers working with these data. In this paper, we review the ways in which data from DMSP/OLS nighttime light images have been applied over the past two decades, focusing on differences in data processing, research trends, and the methods used among the different application areas. Five main datasets extracted from this database have led to many studies in various research areas over the last 20 years, and each dataset has its own strengths and limitations. The number of publications based on this database and the diversity of authors and institutions involved have shown promising growth. In addition, researchers have accumulated vast experience retrieving data on the spatial and temporal dynamics of settlement, demographics, and socioeconomic parameters, which are “hotspot” applications in this field. Researchers continue to develop novel ways to extract more information from the DMSP/OLS database and apply the data to interdisciplinary research topics. We believe that DMSP/OLS nighttime light data will play an important role in monitoring and analyzing human activities and natural phenomena from space in the future, particularly over the long term. A transparent platform that encourages data sharing, communication, and discussion of extraction methods and synthesis activities will benefit researchers as well as public and political stakeholders.
Microbial reverse electrodialysis cells (MRECs) combine power generation from salinity gradient energy using reverse electrodialysis (RED), with power generation from organic matter using a microbial fuel cell. Ammonium bicarbonate can be used to convert waste heat into high (HC) and low salt concentration (LC) solutions for use in the RED stack, but nitrogen crossover into the anode chamber must be minimized to foster a healthy microbial community. To reduce nitrogen crossover, an additional low concentration (LC) chamber was inserted before the anode using an additional anion exchange membrane (AEM) next to another AEM, and filled with different amounts of anion or cation ion exchange resins. Addition of the extra AEM increased the ohmic resistance of the test RED stack from 103 Ω-cm2 (1 AEM) to 295 Ω-cm2 (2 AEMs). However, the use of the anion exchange resin decreased the solution resistance of the LC chamber by 74% (637 Ω-cm2, no resin; 166 Ω-cm2 with resin). Nitrogen crossover into the anode chamber was reduced by up to 97% using 50% of the chamber filled with an anion exchange resin compared to the control (no additional chamber). The added resistance contributed by the use of the additional LC chamber could be compensated for by using additional LC and HC membrane pairs in the RED stack.
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.
Anthropogenic sky glow (a result of light pollution) combines with the natural background brightness of the night sky when viewed by an observer on the earth’s surface. In order to measure the anthropogenic component accurately, the natural component must be identified and subtracted. A model of the moonless natural sky brightness in the V-band was constructed from existing data on the Zodiacal Light, an airglow model based on the van Rhijn function, and a model of integrated starlight (including diffuse galactic light) constructed from images made with the same equipment used for sky brightness observations. The model also incorporates effective extinction by the atmosphere and is improved at high zenith angles (>80°) by the addition of atmospheric diffuse light. The model may be projected onto local horizon coordinates for a given observation at a resolution of 0.05° over the hemisphere of the sky, allowing it to be accurately registered with data images obtained from any site. Zodiacal Light and integrated starlight models compare favorably with observations from remote dark sky sites, matching within ± 8 nL over 95% of the sky. The natural airglow may be only approximately modeled, errors of up to ± 25 nL are seen when the airglow is rapidly changing or has considerable character (banding); ± 8 nL precision may be expected under favorable conditions. When subtracted from all-sky brightness data images, the model significantly improves estimates of sky glow from anthropogenic sources, especially at sites that experience slight to moderate light pollution.
Preliminary results of a study of the night sky background
brightness around the city of Madrid using Sky Quality
Meter (SQM) photometers are presented.
DataFretrieval methodology includes an automa+c
procedure to measure from a moving vehicle which
allows to speed up the data gathering.
The night sky brightness, an astronomical quality
parameter that accounts for luminous flux from the sky, is
closely related with the light pollu+on.
The map with the spa+al distribu+on of the night sky
brightness around Madrid has been compared to the light
pollu+on as measured with calibrated satellite imagery
and nocturnal images taken by astronauts aboard the
Interna+onal Space Sta+on (ISS).
Aladin is the CDS interactive sky atlas, used for source identification
and interpretation, multiwavelength cross-identifications and data
quality control. Aladin provides an image server which contains
reference images from scanned Schmidt surveys: from DSS I, DSS II, and
images digitized by the MAMA-CAI machine with a better resolution for
crowded fields. It allows the overlaying of information extracted from
the Simbad database, the VizieR catalogue server, and private
catalogues. VizieR contains the catalogues obtained from Schmidt surveys
such as GSC 1.2 and USNO 2.0 as well as more than 2000 astronomical
reference catalogues or tables from all the main astronomical journals.
Two different WWW services are presently available: (1) The Aladin
Previewer, a quick view facility gives access to images of objects from
the various CDS services on the WWW. (2) Linked to this quick view
facility, the Aladin-Java interface includes interactive graphical
processing and source overlay The XWindow interface available for French
labs and CDS co-workers includes a source extraction facility as well as
image compression solutions for image transfer.
The Wide Field Camera 3 (WFC3) is a fourth-generation imaging
instrument. It was installed in the Hubble Space Telescope (HST) during
Servicing Mission 4 (SM4) in May 2009. WFC3 saw first light on June 24,
2009, following the cooling of its detectors. Servicing Mission 4
Observatory Verification (SMOV) activities were completed in late August
2009, and were followed by the Cycle 17 calibration and science
programs.
This WFC3 Instrument Handbook has been prepared by the WFC3 team at
STScI. It is the basic technical reference manual for WFC3 observers.
The information in this Handbook is intended to be useful for Cycle 21
Phase I proposers, for the subsequently selected General Observers (GOs)
as they prepare their Phase II specifications, and for those analyzing
WFC3 data. The HST Primer and the HST Call for Proposals also contain
valuable information for proposers, and the Call for Proposals is the
final authority on HST policy.
This edition of the WFC3 Instrument Handbook (Version 5.0) was written
near the end of the execution of the Cycle 19 calibration plan. It
supersedes Version 4.0, and includes results from analysis of the first
three cycles of on-orbit performance.