Multispectral characterization of urban lighting transitions and atmospheric scattering impacts on dark-sky preserves using SDGSAT-1 glimmer imagery

This study presents a comprehensive framework for the radiometric restoration, multispectral classification, and environmental impact assessment of urban lighting using Sustainable Development Science Satellite (SDGSAT-1) Glimmer Imager data. Focusing on the TÜBİTAK National Observatory (TUG) in Antalya and the Eastern Anatolia Observatory (DAG) in Erzurum within the Türkiye National Observatories in Türkiye, we developed a radiance-based restoration workflow that strictly preserves faint stray light signals, validated by a strong log-linear correlation (r ≈ − 0.94) with in-situ Sky Quality Meter (SQM) measurements. Discrete classification revealed a marked “spectral shift” in Antalya, where white light emitting diodes (LED) coverage reached 9.2% driven by commercial zones, whereas Erzurum retained a spectrally homogeneous high-pressure sodium infrastructure (> 77%). Crucially, a physically-based atmospheric scattering risk model uncovered a counter-intuitive phenomenon: despite Antalya’s larger footprint, Erzurum yielded a significantly higher total risk score (76,069 vs. 56,947). This paradox is resolved by distinguishing between geometric threats, driven by the sheer proximity of Erzurum’s core to DAG site, and spectral threats, caused by the high scattering efficiency of Antalya’s distant coastal LEDs. These findings demonstrate that SDGSAT-1 provides actionable evidence for differentiated conservation strategies, specifically, strict shielding for intensity-driven risks and spectral filtering for spectrum-driven threats.