A Simple Method for Near-Real-Time Monthly Nighttime Light Image Production

Abstract

Compared with previous nighttime light (NTL) data, the Black Marble product developed by NASA in recent years is the most advanced NTL product, which plays an important role in regional activity monitoring and special events (process) tracking due to its excellent timeliness (near-real-time release) and global data coverage capability. Currently, among the Black Marble products, the VNP46A2 product is not updated in a timely manner and VN46AX is still under development. Thus, VNP46A1, which is released in near real time, has become a key product available to the public, although it is affected by cloud cover and moonlight. To obtain high-quality near-real-time monthly NTL images and reduce the data gaps before VNP46AX is released, a simple processing scheme based on VNP46A1 is proposed in this letter. The results show that the proposed processing chain can effectively filter cloud-polluted pixels and alleviate the interference of moonlight radiation. The near-real-time monthly NTL (NRTMNTL) data generated by the scheme achieve a higher correlation with VNP46A2 and present a better visual purity. The near-real-time data availability and parameter-free input make the proposed scheme more applicable for short-period events tracking.