A NOVEL SPECTRAL LINEAR TRANSFORMATION TO ESTIMATE NON-PHOTOSYNTHETIC VEGETATION COVERAGE IN NORTH ASIAN STEPPE

The effect of snowmelt on vegetation is not immediate but has a mean response lag of 38.5 d. As precipitation and snowmelt increase, the response time shortens. More complex than these factors, temperature shortens the response time in colder regions while lengthening it in warmer areas. Furthermore, vegetation in arid regions is more dependent on water than heat, and low-vegetation areas rely more on sub-snow habitats than external climatic factors.

Nighttime light (NTL) data aids urban planning and disaster monitoring. Our study introduces HDNTL, a daily NTL dataset for 653 major cities (population >1 M by 2025) from 2012–2024, enhancing NASA's VNP46A2 accuracy by correcting spatial mismatches, angular effects, and filling small missing holes via spatiotemporal interpolation. Validated against high-resolution NTL datasets and ground-truth records, HDNTL enables precise monitoring of nighttime human activities.