The Terra Vega Active Light Source: A First Step in a New Approach to Perform Nighttime Absolute Radiometric Calibrations and Early Results Calibrating the VIIRS DNB

Giuliani

Franziskakis

et al. 2019

Maintaining records of artisanal and small-scale mining sites in developing countries requires considerable effort, so it would be beneficial if Earth observation data from space could assist in the identifying and monitoring of such sites. Artificial light emissions are common at industrial-scale mining sites and have been associated with small-scale illegal mining in some contexts. Here, we examine whether known artisanal and small-scale mining sites in the Democratic Republic of the Congo (DRC) are associated with observations of night light emissions by the Visible Infrared Imaging Radiometer Suite Day/Night Band (DNB). Light emissions from the mining sites were not observed: the radiance observed from the sites was near zero and nearly identical to that observed for a set of randomly-chosen locations in the same region. While it is the case that DNB night lights’ products provide useful data in other resource extraction contexts, they do not appear to be useful for identifying artisanal mining sites in the DRC.

Section: Night Lights' Data and Analysismentioning

confidence: 89%

Artisanal and Small-Scale Mining Sites in the Democratic Republic of the Congo Are Not Associated with Nighttime Light Emissions

Giuliani

Franziskakis

et al. 2019

“…A temporally consistent NTL time series extending from DMSP/OLS to VIIRS/DNB is highly desirable, yet still a huge challenge, due to differences in passing time, onboard calibration, spatial resolution, and other considerations (see , as well as Zheng et al, 2019, for examples of inter-calibration between DMSP/OLS and VIIRS/DNB). Ground-based stable and radiometrically calibrated light sources may offer a useful approach for inter-calibration between night-time lights sensors, as well as for validating the performance of these sensors, as attempted by Hu et al (2018b) and Ryan et al (2019).…”

Section: Consistent Nightlight Time Series Across Different Platforms and Sensorsmentioning

confidence: 99%

Remote sensing of night lights: A review and an outlook for the future

Levin

Remote Sensing of Environment

Zhang³

et al. 2020

547

247

Remote sensing of night light emissions in the visible band offers a unique opportunity to directly observe human activity from space. This has allowed a host of applications including mapping urban areas, estimating population and GDP, monitoring disasters and conflicts. More recently, remotely sensed night lights data have found use in understanding the environmental impacts of light emissions (light pollution), including their impacts on human health. In this review, we outline the historical development of night-time optical sensors up to the current state of the art sensors, highlight various applications of night light data, discuss the special challenges associated with remote sensing of night lights with a focus on the limitations of current sensors, and provide an outlook for the future of remote sensing of night lights. While the paper mainly focuses on space borne remote sensing, ground based sensing of night-time brightness for studies on astronomical and ecological light pollution, as well as for calibration and validation of space borne data, are also discussed. Although the development of night light sensors lags behind day-time sensors, we demonstrate that the field is in a stage of rapid development.The worldwide transition to LED lights poses a particular challenge for remote sensing of night lights, and strongly highlights the need for a new generation of space borne night lights instruments. This work shows that future sensors are needed to monitor temporal changes during the night (for example from a geostationary platform or constellation of satellites), and to better understand the angular patterns of light emission (roughly analogous to the BRDF in daylight sensing). Perhaps most importantly, we make the case that higher spatial resolution and multispectral sensors covering the range from blue to NIR are needed to more effectively identify lighting technologies, map urban functions, and monitor energy use.

“…Even after zero-point correction, the radiances observed by DNB are not perfectly constant. 37 One obvious reason for this is atmospheric extinction: when the atmosphere is less transparent, artificial light sources appear less bright (although their surroundings may appear more bright due to scattering into the line of sight 29 ). Atmospheric extinction changes from night to night, and total extinction along a given line of sight depends on nadir angle; at higher nadir angles, light propagates through a longer path length of atmosphere, approximately as cos À1 .…”

Section: Radiance Correctionmentioning

confidence: 99%

Direct measurement of the contribution of street lighting to satellite observations of nighttime light emissions from urban areas

Lighting Research & Technology

Ruby

Kuechly

et al. 2020

Nighttime light emissions are increasing in most countries worldwide, but which types of lighting are responsible for the increase remains unknown. Also unknown is what fraction of outdoor light emissions and associated energy use are due to public light sources (i.e. streetlights) or various types of private light sources (e.g. advertising). Here we show that it is possible to measure the contribution of street lighting to nighttime satellite imagery using ‘smart city’ lighting infrastructure. The city of Tucson, USA, intentionally altered its streetlight output over 10 days, and we examined the change in emissions observed by satellite. We find that streetlights operated by the city are responsible for only 13% of the total radiance (in the 500–900 nm band) observed from Tucson from space after midnight (95% confidence interval 10–16%). If Tucson did not dim their streetlights after midnight, the contribution would be 18% (95% confidence interval 15–23%). When streetlights operated by other actors are included, the best estimates rise to 16% and 21%, respectively. Existing energy and lighting policy related to the sustainability of outdoor light use has mainly focused on street lighting. These results suggest an urgent need for consideration of other types of light sources in outdoor lighting policy.