16 research outputs found
Citizen Science Provides Valuable Data for Monitoring Global Night Sky Luminance
The skyglow produced by artificial lights at night is one of the most dramatic
anthropogenic modifications of Earthâs biosphere. The GLOBE at Night citizen
science project allows individual observers to quantify skyglow using star
maps showing different levels of light pollution. We show that aggregated
GLOBE at Night data depend strongly on artificial skyglow, and could be used
to track lighting changes worldwide. Naked eye time series can be expected to
be very stable, due to the slow pace of human eye evolution. The standard
deviation of an individual GLOBE at Night observation is found to be 1.2
stellar magnitudes. Zenith skyglow estimates from the ââFirst World Atlas of
Artificial Night Sky Brightnessââ are tested using a subset of the GLOBE at
Night data. Although we find the World Atlas overestimates sky brightness in
the very center of large cities, its predictions for Milky Way visibility are
accurate
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
Changes in outdoor lighting in Germany from 2012-2016
Changes in the total lit area and the radiance of stably lit area in the German federal states from 2012-2016 were investigated using the Day-Night Band of the Visible Infrared Imaging Radiometer Suite. Most states increased in both lit area and radiance. The lit area of Bayern and Schleswig-Holstein grew rapidly, at annual rates of 9.7% and 8.8% respectively. ThĂŒringen was dramatically different from the other states, with a 4.5% annual decrease in lit area, and a 17% annual decrease in the radiance of stably lit areas. In at least some cases, the increases in lighting in Bayern area associated with transitions to LEDs, which may not be indicative of a transition towards sustainable lighting. In addition to these results, this paper discusses the role of remotely sensed nighttime data within the context of sustainable lighting
Co-Designing Mobile Applications for Citizen Science Projects - First Results of the NachtlichtBĂŒHNE Project
Nachtlicht-BĂŒHNE - Co-Designing App-Based Citizen Science Projects Related to Nighttime Light Phenomena
Nachtlicht-BĂŒHNE - collecting complete lighting inventories with a co-design citizen science platform for nighttime light phenomena
Reducing Variability and Removing Natural Light from Nighttime Satellite Imagery: A Case Study Using the VIIRS DNB
Temporal variation of natural light sources such as airglow limits the ability of night light sensors to detect changes in small sources of artificial light (such as villages). This study presents a method for correcting for this effect globally, using the satellite radiance detected from regions without artificial light emissions. We developed a routine to define an approximate grid of locations worldwide that do not have regular light emission. We apply this method with a 5 degree equally spaced global grid (total of 2016 individual locations), using data from the Visible Infrared Imaging Radiometer Suite (VIIRS) Day-Night Band (DNB). This code could easily be adapted for other future global sensors. The correction reduces the standard deviation of data in the Earth Observation Group monthly DNB composites by almost a factor of two. The code and datasets presented here are available under an open license by GFZ Data Services, and are implemented in the Radiance Light Trends web application