Assessment of a new fine-resolution nighttime light imagery from the Yangwang-1 ('Look up 1') satellite

Abstract

High-resolution nighttime light (NTL) satellite images are needed for monitoring human activities and socioeconomic dynamics at fine scales, but such NTL data are very limited. On June 11, 2021, China launched the Yangwang-1 ('Look Up 1') satellite, which is a small optical space telescope that detects near-earth asteroids, but its visible band sensor can also collect NTL images. It provides a new fine-scale NTL data source. This study assessed the quality and capability of Yangwang-1 NTL imagery for capturing artificial lights. The results show that Yangwang-1 has equivalent quality with the state of the art in NTL remote sensing (e.g., Visible Infrared Imaging Radiometer Suite (VIIRS), Luojia-1) and some aspects are even better. Specifically, Yangwang-1 has a higher spatial resolution (38 m at the nadir), high radiometric consistency with VIIRS ( R^2 =0.83 ), higher sensitivity to low lights than Luojia-1, better image quality in the spatial domain (lower Blind/Referenceless Image Spatial Quality Evaluator (BRISQUE) index than Luojia-1 and VIIRS by 32% and 61%, respectively), and a 420-700 nm broadband that can better detect artificial light and is less influenced by the absorption of the atmosphere. Yangwang-1 NTL data can be applied to various fields, including urban mapping, road network extraction, disaster detection, monitoring light pollution, illegal fishing, fires, and human settlements, and mapping associated energy infrastructures at fine scales.