Dynamics and Spatial Distribution of Global Nighttime Lights

Abstract

We analyze the dynamics, and the spatial distribution of nighttime light using the open source data of the Defense Meteorological Satellite Program of the U.S. Air Force. A detailed analysis of the relevant literature and our study of the database allow us to set up a best-practice for the use of nighttime light images in different research projects. Over the past 17 years, we document a gradual shift of the light world center moving eastwards over a distance of roughly 1000 km, at a pace of about 60 km per year. We introduce the new concept of spatial light Gini coefficients. When removing unlit land from the calculations, we find that the Lorenz curves and the Gini coefficients converge for all the countries in our analysis, suggesting a universal pattern across different countries of human settlements. We also document a gradual increase of the spatial light Gini coefficient over most countries over the past 17 years, indicative of a centralization of light. This is explained by a larger growth of dimly lit surface (49%) compared with bright areas (19%) between 1992 and 2009. Finally, a detailed analysis of bright light (city) growth covering 160 different countries shows that nighttime light images provide the perfect tool to monitor the expansion of developing countries (like India and Brazil), the growth of new agglomeration sizes (like Shanghai in China or the Nile delta in Egypt), the regression in countries suffering from demographic decline and a reduction in urban population (like Russia and the Ukraine) and the success of light pollution abatement programs in western countries like Canada and the United Kingdom.

Keywords: satellite nighttime lights, spatial light Gini coefficient, nighttime light growth, economic development, agglomeration growth, light pollution

JEL Classification: C80, J10, O10, Q5