Capturing the Urban Divide in Nighttime Light Images with the New Generation of High-Resolution Night Light Images and Citizen Science Data.

The new generation of high-resolution nightlight sensors (e.g., SDGSat-1, Jilin-1) with a spatial resolution of 10 m and below can capture the spatial patterns and light colours of Artificial Light at Night (ALAN). Our research leverages these new generations of high spatial and spectral resolution nightlight images and in situ data collection by citizen science and through nightlight mobile applications to accurately assess electricity access and reliability in Sub-Saharan African cities. More than 50% of Sub-Saharan Africa’s population (around 600 million people) has no access to electricity, and a large part (estimated at 80%) does not have access to stable electricity- data coming from the global dataset "Global Electrification Project" (World Bank). Existing global electricity access datasets use low-resolution satellite data (such as VIIRS) and, therefore, remain uncertain and misrepresent that many of these cities have universal access to electricity. In reality, many residents lack formal grid connections and face unreliable electricity supply. We conducted local fieldwork in informal settlements to capture access gaps and relate the results to high-resolution ALAN data. Surveyed areas experiencing unstable access to electric power, leading to frequent outages, such as Nigeria's average of over 32 monthly outages. Results show that field observations in combination with high-resolution night light images can provide a more accurate and nuanced understanding of electricity distribution and reliability to understand the gaps in SDG-7 across sub-Saharan Africa. Our study provides insights into how global monitoring of the multiple dimensions of urban poverty can include access to electricity as an essential indicator. Furthermore, emphasises incorporating nighttime light observations into global urban poverty monitoring to include electricity access as an essential indicator. It also outlines the need for advanced satellite-based sensors to support comprehensive urban poverty mapping, in line with the European Space Agency-funded “NightWatch” project.