Satellite helps distinguish various sources of light

Chinese scientists have turned to science satellite SDGSAT-1 as a tool to manage the impact of modern illumination sources on the urban environment, according to a recent study.

The study, conducted by scientists from the Aerospace Information Research Institute of the Chinese Academy of Sciences, was published recently in the International Journal of Digital Earth.

According to the study, the constant need for decarbonization has led to the replacement of artificial light at night, or ALAN, with light-emitting diodes, or LEDs, inducing blue light pollution and its associated adverse effects. As a result, there is an urgent need to develop a tool to distinguish various illumination sources rapidly, accurately and on a large scale.

The scientists believe that the SDGSAT-1 can play this role by supplementing existing nighttime light data with multispectral and high-resolution features.

The scientists used Beijing as an example and found that their approach was highly effective in distinguishing the various types of light sources, boasting an overall accuracy of 92 percent for ALAN and 95 percent for streetlights.

The analysis of the SDGSAT-1 images revealed clear and distinct illumination patterns, which showed spatial heterogeneity in ALAN along Beijing's 5th Ring Road, providing valuable information about how light pollution varies across different urban areas.

In addition, the scientists discovered statistically significant disparities across different types of roads and streetlights, illustrating the influence of urban planning and infrastructure on the prevalence of specific lighting technologies.

"This work emphasizes the crucial role of SDGSAT-1 in analyzing ALAN, providing valuable insights in urban lighting management," said the study.

Launched into space on Nov 5, 2021, SDGSAT-1 is the world's first space science satellite dedicated to serving the UN 2030 Agenda for Sustainable Development.

The satellite is designed to provide space observation data for the monitoring, evaluation and study of interactions between humans, nature and sustainable development, according to its developer, the Chinese Academy of Sciences.

Last September, SDGSAT-1 provided the world's first atlas of urban nighttime light remote-sensing data, lending support for the research on urban sustainable development. The atlas contains 10-meter resolution nighttime light data from 147 cities in 105 countries.

Xinhua