Originally published in GIM International magazine, by NLT's Chief Scientist and colleagues.
Images of Earth taken at night are revolutionizing our ability to measure and understand nearly every dimension of human activity on Earth, and allow us to glimpse human–Earth interactions in near real time. The COVID-19 outbreak exemplifies how nighttime lights can help us understand the impacts of shocks on populations, economies, and markets. Given the interdisciplinary nature of remote sensing–based socioeconomic research, a special issue of Remote Sensing journal will bring together original and novel studies demonstrating innovative applications of nighttime-lights-based analysis to broaden our understanding of human society and its implications.
Seeing the Impacts of COVID-19 at Night
In mid-December 2019, COVID-19 began emerging in Wuhan, China, and in just 30 days spread to the entire country, causing significant impacts not only on people's health but on the entire economy, the job market, and daily life. Within several weeks the disease was spreading globally, with millions of confirmed cases recorded around the world and significant implications for global economies.
The need to track and predict outbreaks, and to understand the impacts of COVID-19 on economies, has led to the use of unique data sources that can help track the spread of the pandemic in close to real time. Satellite observations — including those taken at night — are becoming a primary source of data for tracking the pandemic's progress and its impacts on energy consumption, transportation, social interactions, critical infrastructure, tourism, and trade. They provide a compelling picture of the large-scale impacts of COVID-19 on Earth, from the impacts of the pandemic on businesses and transportation networks to monitoring the gradual recovery of cities around the world. The idea of using nighttime lights to understand pandemics is not new; previous studies have shown how nighttime lights can be used to estimate seasonal measles epidemics, which are directly linked to spatiotemporal changes in population density as measured by anthropogenic light emissions.
Shedding Light on Earth
The use of nighttime-lights observations to monitor pandemics is only one example of how satellite observations can help us better understand processes on Earth. Since the early 1990s, with the launch of DMSP-OLS, remotely sensed observations of nighttime lights have been a key instrument for understanding almost every aspect of human activity on Earth — particularly in data-scarce regions, without being filtered through national data agencies that are potentially inefficient or biased. Today, newer sensors such as VIIRS/DNB provide nighttime-light data at even higher spatial resolution and granularity. With advances in the availability and quality of nighttime-light data, improvements in storage, and new analytical methods, there is an ongoing increase in scientific applications that exploit remotely sensed nighttime lights to measure our world.
Nighttime-lights observations provide a unique glimpse into human behavior, socio-economic patterns, and the nature of human–Earth interactions. They are especially vital in countries where timely, accurate, and reliable statistical or administrative data is poor — offering insights into where people are, how people move, patterns of economic development, and the economic impacts of infrastructure investments. While nighttime-light observations can be noisy and carry inherent measurement errors, there is general consensus that they represent many dimensions of human presence and activity on Earth.
Today, nighttime lights are used to measure the extent and characteristics of urbanization processes, estimate economic growth at national and sub-national levels, map global poverty, track local household wealth, map population density and migration, understand armed conflicts, measure accessibility to electricity and electrification, community resilience, fishing activity, coral reef health, and more. Recently, researchers have also shown that nighttime lights can help explain brain development and human behavior.
About New Light Technologies
New Light Technologies (NLT) is a Washington, DC-based firm with 25+ years of experience delivering:
- Geospatial systems and enterprise GIS
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NLT supports federal, state, and international organizations in operationalizing data for mission impact.