Night Light Emissions Research Articles

The Economic Dynamics After a Flood: Evidence from Satellite Data

This study investigates the effect of flash floods on local economic activity in Central America and the Caribbean. I measure these rarely analyzed floods by constructing a high-resolution, physically based index of flash flood occurrence from satellite data and connect these to changes in local night light emissions. After accounting for tropical cyclone activity, flash floods have a delayed, short-term negative effect on economic activity. In countries with a low to medium human development index (HDI), the average negative effect can be up to 5.6%\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$5.6\\%$$\\end{document} in the following months. Countries with higher HDI appear more resilient and are only marginally affected. Also, flash floods exhibit a minor positive spatial spillover in low to medium HDI countries, besides their more substantial local negative effect. Due to their high frequency, flash floods have a detrimental effect on local economic growth in developing countries that will likely be exacerbated by climate change. (JEL )

The complex regional effects of macro-institutional change: evidence from EU enlargement over three decades

AbstractThe EU enlargement process has thrust EU internal border regions into the spotlight of the European single market. This study explores how this specific macro-institutional change has impacted their socio-economic development. Tracking outcomes across four EU enlargement waves from 1986 to 2007, we identify integration effects across EU NUTS3 regions. Pooled over all waves and border regions, positive integration effects emerge for per capita GDP, labor productivity, patents per capita, and night light emissions in border regions compared to non-border areas. These effects diminish with increasing spatial distance from the enlargement border. At a detailed level, structural heterogeneities become evident across enlargement waves and region types. Internal border regions in established EU member countries benefit relatively in terms of GDP per capita and labor productivity but experience relative declines in employment rates and population. In contrast, border regions in new member countries, particularly during the 2004 and 2007 eastern enlargements, gain from deepening economic integration in terms of population and employment growth. Sector-specific estimations indicate post-enlargement specialization of economic activities in border regions in line with standard trade theories.

Uncovering the veil of night light changes in times of catastrophe

Abstract. Natural disasters have large social and economic consequences. However, adequate economic and social data to study subnational economic effects of these negative shocks are typically difficult to obtain especially in low-income countries. For this reason, the use of night light data is becoming increasingly popular in studies which aim to estimate the impacts of natural disasters on local economic activity. However, it is often unclear what observed changes in night lights represent exactly. In this paper, we examine how changes in night light emissions following a severe hurricane relate with local population, employment, and income statistics. We do so for the case of Hurricane Katrina, which struck the coastline of Louisiana and Mississippi in August 2005. Hurricane Katrina is an excellent case for this purpose as it is one of the biggest hurricanes in recent history in terms of human and economic impacts, it made landfall in a country with high-quality sub-national socioeconomic data collection, and it is covered extensively in the academic literature. We find that overall night light changes reflect the general pattern of direct impacts of Katrina as well as indirect impacts and subsequent population and economic recovery. Our results suggest that change in light intensity is mostly reflective of changes in resident population and the total number of employed people within the affected area and less so but positively related to aggregate income and real GDP.

Tax Haven Welfare and the Crackdown on Secrecy: Evidence from Night Light Emissions

Tax Haven Welfare and the Crackdown on Secrecy: Evidence from Night Light Emissions

Tax Haven Welfare and the Crackdown on Secrecy: Evidence from Night Light Emissions

Tax Haven Welfare and the Crackdown on Secrecy: Evidence from Night Light Emissions

Using VIIRS nightlights to estimate the impact of the 2015 Nepal earthquakes

We use Visible Infrared Imaging Radiometer Suite (VIIRS) nightlight data to model the impact of the 2015 Nepal earthquakes. More specifically, the data—showing nightlight emissions—are used to examine the extent to which there is a difference in nightlight intensity between cells damaged in the earthquake versus undamaged cells based on (1) mean comparisons; and (2) fixed effect regression models akin to the double difference method. The analysis is carried out for the entire country as well as smaller regions in and around the Central area and Kathmandu, which were the hardest hit areas. Overall, the regressions find a significant and negative effect from the initial shock, followed by a positive net effect from aid and relief efforts, which is consistent with what one would expect to find. However, the mean analysis results are inconclusive and there is substantial noise in the nightlight measurements due to how the values are produced and persistent cloud cover over Nepal.

State reach and development in Africa since the 1960s: new data and analysis

AbstractProminent arguments hold that African states’ geography limits state capacity, impedes public service provision, and slows economic development. To test this argument, I collect comprehensive panel data on a proxy of local state capacity, travel times to national and regional capitals. These are computed on a yearly 5 × 5 km grid using time-varying data on roads and administrative units (1966–2016). I use these data to estimate the effect of changes in travel times to capitals on local education provision, infant mortality rates, and nightlight emissions. Within the same location, decreases in travel times to its capitals are robustly associated with improved development outcomes. The article advances the measurement of state capacity and contributes to understanding its effects on human welfare.

Spatio-Temporal Variations in Night Lights, Economy and Night Light Emissions in States of India

Spatio-Temporal Variations in Night Lights, Economy and Night Light Emissions in States of India

Ancient colonialism and the economic geography of the Mediterranean

Abstract This article investigates the legacy of ancient Phoenician, Greek and Etruscan colonialism in shaping the economic geography of the Mediterranean region. Utilising historical data on ancient colonies and current data on population density and night light emissions (as a proxy for economic activity), we find that geographical areas colonised by these ancient civilisations have higher population density and economic activity in the present day. We also find that ancient colonialism affected the origin and evolution of the urban system of cities and settlements prevalent in the Mediterranean region.

Quantifying the influence of urban sources on night light emissions

Light pollution in urban locations is a complex, serious problem, but researchers have paid more attention to light pollution on natural, non-urban environments. Understanding the sources of artificial light radiance intensity is the first step in minimizing damage from light pollution in urban areas. The purpose of this study is to quantitatively examine the relationship between light pollution and urban built environments. We developed databases for a series of urban–built environment data with composite Visible Infrared Imaging Radiometer Suite day-night band (VIIRS-DNB) data from the Earth Observation Group of the United States National Oceanic Atmospheric Administration’s National Geophysical Data Center to apply regression models (production functions) with grid cells at a spatial resolution of 15 arc seconds. Based on the results, we identified urban-development and land-use characteristics and built-environment factors that caused high levels of light emissions in a city. First, high levels of light emissions are associated with urban spatial-development patterns, such as roads, office buildings, commercial facilities, higher proportions of “station influence areas,” and urban-development intensity. Second, more seriously, the infiltration of commercial facilities into urban residential areas makes them brighter and increases the risk of exposure to light pollution. Therefore, the development of commercial areas and commercial facilities that emit light should be properly managed, especially for areas mixed with residential land use. Third, our quantitative model with intra-city-level analyses can estimate a high level of the baseline light-emission propensity in Seoul, which indicates that a city’s light-emission intensity can be highly associated with its sociocultural and institutional characteristics for lighting and light uses.

Urbanization that hides in the dark – Spotting China’s “ghost neighborhoods” from space

The excessive planning and construction of new cities and towns as well the massive expansion of planned settlement areas in China reveals a surprising phenomenon: extensive newly constructed areas that are characterized by severe under capacity. This phenomenon is described as “ghost city” and usually appears at the intra-urban scale. However, current data and methods are inappropriate to detect this phenomenon at this intra-urban scale for entire China. Besides, most studies neglect the usual immigration period of newly built areas. In this study, we suggest a new term, the “ghost neighborhood”, which refers to a new residential neighborhood that still runs at severe under capacity after a typical immigration period of five to six years. Based on this conceptual baseline, we identify “ghost neighborhoods” across China by developing a methodology to gradually exclude the “non-ghost areas” by predominantly relying on night-light emissions. The process is based on LJ1-01 night-light data, TanDEM-X data and Global Urban Footprint data, which feature evident advantages in spatial resolutions while being available for entire China. The main results are as follows: 1) we identify 1048 “ghost neighborhoods” across the urban landscapes of China with a total coverage area of 353.64 km2; they are estimated to have the capacity to house 13.6 million people; 2) the identified “ghost neighborhoods” are particularly frequent and large in the dynamically urbanizing regions, such as the Pearl River Delta, the Yangtze River Delta and the entire Shandong province.

Rebels, Revenue and Redistribution: The Political Geography of Post-Conflict Power-Sharing in Africa

AbstractDo rebel elites who gain access to political power through power-sharing reward their own ethnic constituencies after war? The authors argue that power-sharing governments serve as instruments for rebel elites to access state resources. This access allows elites to allocate state resources disproportionately to their regional power bases, particularly the settlement areas of rebel groups' ethnic constituencies. To test this proposition, the authors link information on rebel groups in power-sharing governments in post-conflict countries in Africa to information about ethnic support for rebel organizations. They combine this information with sub-national data on ethnic groups' settlement areas and data on night light emissions to proxy for sub-national variation in resource investments. Implementing a difference-in-differences empirical strategy, the authors show that regions with ethnic groups represented through rebels in the power-sharing government exhibit higher levels of night light emissions than regions without such representation. These findings help to reconceptualize post-conflict power-sharing arrangements as rent-generating and redistributive institutions.

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

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.

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

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.

Group Size and Political Representation Under Alternate Electoral Systems

We examine the effect of group size of minorities on their representation in national government under majoritarian (MR) and proportional (PR) electoral systems. We first establish a robust empirical regularity using an ethnicity-country level panel data comprising 438 ethno-country minority groups across 102 democracies spanning the period 1946–2013. We show that a minority group’s population share has no relation with its absolute representation in the national executive under PR but has an inverted U-shaped relation under MR. The pattern is stable over time and robust to alternate specifications. The developmental outcomes for a group proxied using stable nightlight emissions in a group’s settlement area follow the same pattern. We reproduce the main results by two separate identification strategies—(i) instrumenting colony’s voting system by that of the primary colonial ruler and, (ii) comparing the same ethnicity across countries within a continent. We argue that existing theoretical framework with a two group set up is not able to explain this pattern. Our proposed model incorporates the spatial distribution of multiple minority groups in a probabilistic voting model and justifies these patterns as equilibrium behavior. The data further validate a critical assumption of the model and its additional comparative static results. Our work highlights that electoral systems can have important effects on power inequality across minorities, and consequently, their well-being.

Light pollution: spatial analysis and potential ecological effects in rural Ireland

Increasing use of artificial light at night has led to many areas across the globe being exposed to light conditions above the natural background level. Research is only now uncovering the impacts of ‘ecological light pollution’ on the environment. Artificial light at night can disrupt circadian rhythms, cause interference with orientation and migration, alter predator/prey interactions and affect other behaviour and physiological features. Intercalibration of Defense Meteorological Satellite Program’s Operational Linescan System images shows that night light emissions in Ireland have increased significantly from 1995 to 2010. In this period, artificial light has spread into previously dark rural areas, including County Mayo where 28% of land surface is designated for habitat and species conservation purposes. To investigate light pollution in rural areas, examination into the conservation area of Owenduff/Nephin Beg Complex was undertaken. Spatial analysis of light measurements taken from Sky Quality Meters surrounding the site were overlaid with species distribution records to determine the proximity of protected species to sources of artificial light at night. Light measurements from the area show pristine night skies according to International Dark Sky Association standards, with one site indicating the presence of localised light pollution. Further work is required to determine if any potential adverse ecological impacts on protected species in the locality are occurring from artificial light at night. The findings of this study provide a foundation for ecological light pollution effects assessment in Ireland. Further work is required to establish the temporal and spatial scales of artificial light in Irish rural areas and determine the specific effects on species present there.

Light pollution: spatial analysis and potential ecological effects in rural Ireland

Increasing use of artificial light at night has led to many areas across the globe being exposed to light conditions above the natural background level. Research is only now uncovering the impacts of ‘ecological light pollution’ on the environment. Artificial light at night can disrupt circadian rhythms, cause interference with orientation and migration, alter predator/prey interactions and affect other behaviour and physiological features. Intercalibration of Defense Meteorological Satellite Program’s Operational Linescan System images shows that night light emissions in Ireland have increased significantly from 1995 to 2010. In this period, artificial light has spread into previously dark rural areas, including County Mayo where 28% of land surface is designated for habitat and species conservation purposes. To investigate light pollution in rural areas, examination into the conservation area of Owenduff/Nephin Beg Complex was undertaken. Spatial analysis of light measurements taken from Sky Quality Meters surrounding the site were overlaid with species distribution records to determine the proximity of protected species to sources of artificial light at night. Light measurements from the area show pristine night skies according to International Dark Sky Association standards, with one site indicating the presence of localised light pollution. Further work is required to determine if any potential adverse ecological impacts on protected species in the locality are occurring from artificial light at night. The findings of this study provide a foundation for ecological light pollution effects assessment in Ireland. Further work is required to establish the temporal and spatial scales of artificial light in Irish rural areas and determine the specific effects on species present there.

Using night light emissions for the prediction of local wealth

Nighttime illumination can serve as a proxy for economic variables in particular in developing countries, where data are often not available or of poor quality. Existing research has demonstrated this for coarse levels of analytical resolution, such as countries, administrative units or large grid cells. In this article, we conduct the first fine-grained analysis of night lights and wealth in developing countries. The use of large-scale, geo-referenced data from the Demographic and Health Surveys allows us to cover 39 less developed, mostly non-democratic countries with a total sample of more than 34,000 observations at the level of villages or neighborhoods. We show that light emissions are highly accurate predictors of economic wealth estimates even with simple statistical models, both when predicting new locations in a known country and when generating predictions for previously unobserved countries.

Sleepless in Town – Drivers of the Temporal Shift in Dawn Song in Urban European Blackbirds

Organisms living in urban environments are exposed to different environmental conditions compared to their rural conspecifics. Especially anthropogenic noise and artificial night light are closely linked to urbanization and pose new challenges to urban species. Songbirds are particularly affected by these factors, because they rely on the spread of acoustic information and adjust their behaviour to the rhythm of night and day, e.g. time their dawn song according to changing light intensities. Our aim was to clarify the specific contributions of artificial night light and traffic noise on the timing of dawn song of urban European Blackbirds (Turdus merula). We investigated the onset of blackbird dawn song along a steep urban gradient ranging from an urban forest to the city centre of Leipzig, Germany. This gradient of anthropogenic noise and artificial night light was reflected in the timing of dawn song. In the city centre, blackbirds started their dawn song up to 5 hours earlier compared to those in semi-natural habitats. We found traffic noise to be the driving factor of the shift of dawn song into true night, although it was not completely separable from the effects of ambient night light. We additionally included meteorological conditions into the analysis and found an effect on the song onset. Cloudy and cold weather delayed the onset, but cloud cover was assumed to reflect night light emissions, thus, amplified sky luminance and increased the effect of artificial night light. Beside these temporal effects, we also found differences in the spatial autocorrelation of dawn song onset showing a much higher variability in noisy city areas than in rural parks and forests. These findings indicate that urban hazards such as ambient noise and light pollution show a manifold interference with naturally evolved cycles and have significant effects on the activity patterns of urban blackbirds.

'Robin Hook': The Developmental Effects of Somali Piracy

Naval counter-piracy measures off Somalia have failed to change the incentives for pirates, raising calls for land-based approaches that may involve replacing piracy as a source of income. This paper evaluates the effects of piracy on the Somali economy to establish which (domestic) groups benefit from ransom monies. Given the paucity of economic data on Somalia, we evaluate province-level market data, nightlight emissions and high resolution satellite imagery. We show that significant amounts of ransom monies are spent within Somalia. The impacts appear to be spread widely, benefiting the working poor and pastoralists and offsetting the food price shock of 2008 in the pirate provinces. Pirates appear to invest their money principally in the main cities of Garowe and Bosasso rather than in the backward coastal communities.