Diverging evolution of light pollution indicators: can the Globe at Night and VIIRS-DNB measurements be reconciled?
Identificadores
URI: https://hdl.handle.net/10481/102904Metadatos
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Elsevier
Materia
Light pollution Glare Globe at night VIIRS-DNB Global change
Fecha
2025-02-10Referencia bibliográfica
Published version: Bará, Salvador y Castro Torres, José Juan. Journal of Quantitative Spectroscopy and Radiative Transfer Volume 335, April 2025, 109378. https://doi.org/10.1016/j.jqsrt.2025.109378
Resumen
The radiance of nighttime artificial lights measured by the VIIRS-DNB instrument on
board the satellite Suomi-NPP increases at an average rate ~2.2 %/yr worldwide, whereas the
artificial radiance of the night sky deduced from the Globe at Night (GAN) unaided-eye
observations of the number of visible stars is reported to increase at an average rate ~9.6 %/yr.
The difference between these two estimates is remarkable. This raises the question of whether
the diverging temporal evolution of these indicators could be due to changes in the spectral
composition of outdoor artificial light, consequence of the current process of replacement of
lighting technologies. This paper presents a model for evaluating the temporal rate of change of
different light pollution indicators and applies it to the VIIRS-DNB vs GAN issue, based on
available data. The results show that the reported difference could be explained by spectral
changes alone, if the visual GAN observations are made with scotopic or mesopic adaptation at
definite times under some particular transition conditions. In case of photopic adapted
observers, however, reconciling these two measurement sets requires the existence of GAN-specific light sources that affect the Globe at Night observations but do not show up in the VIIRS-DNB data. The lumen emissions of these GAN-specific sources for photopic observers should
increase at a rate larger than 9%/yr worldwide.