Picture a clear night sky, adorned with countless stars that fill us with wonder and remind us of how they guided travellers in the past. But have you ever stopped to think about what it would be like to look down on Earth from above?
In our modern lives, we rely on artificial lighting at night, and if we were to take that aerial perspective (made possible with the numerous satellites hovering over Earth), we would discover fascinating details and untold stories waiting to be unveiled.
The Day-Night Band (DNB) sensor, part of the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi National Polar-orbiting Partnership (SNPP) satellite, captures the illumination emitted by human activities during night-time globally. This involves the acquisition and analysis of the brightness, intensity, and spatial distribution of lights visible from space sensors during nocturnal hours.
This data provides valuable insights into various phenomena, including urbanization patterns, economic activity, land use changes, environmental impacts, and social dynamics. It offers a unique perspective on human presence and activity during night-time, facilitating the monitoring and comprehension of the interactions between human society and the natural environment.
Urbanization and population distribution can be studied using night-time light data. By examining the brightness and spatial distribution of lights, we can identify urban areas, monitor their expansion, and evaluate the effectiveness of urban planning policies. For example, cities such as Kuala Lumpur, Johor Bahru, Georgetown, Kuantan, and Ipoh exhibit higher levels of illumination compared to less populated and less developed areas.
This observation is supported by myCencus 2020 data, which reveals that these areas are densely populated. Kuala Lumpur has a population density of 8,157 people per square kilometer (p/sqkm), Johor Bahru has a density of 1,605 p/sqkm, Georgetown has a density of 4,417 p/sqkm, Kuantan has a density of 185 p/sqkm, and Ipoh has a density of 681 p/sqkm. Consequently, the night-time light data proves to be valuable for infrastructure planning, as it helps identify areas that require streetlights or improved lighting to meet the residents’ needs.
The intensity and extent of this data contribute significantly to environmental monitoring. It assists in monitoring deforestation, wildfires, and the encroachment of human activities into natural habitats. By identifying deforestation hotspots, efforts can be focused on protecting vulnerable areas, implementing regulations, and supporting sustainable land management practices. Moreover, these findings provide valuable insights for policymakers to develop targeted strategies to mitigate deforestation and promote reforestation initiatives, while also helping assess the impact of human activities on ecosystems and designing effective conservation strategies.
Furthermore, the intensity and spatial distribution of lights data can be utilised to study economic activity and socio-economic development. It can serve as a proxy for economic indicators such as energy consumption, economic growth, and urbanization rates. Analysing these patterns allows for the examination of regional disparities, identification of areas experiencing economic prosperity, and evaluation of the effectiveness of poverty alleviation programs.
During natural disasters or humanitarian crises, this light data proves invaluable for emergency response and recovery efforts. By comparing pre- and post-event images, utility providers and authorities can identify areas without lights, indicating power outages or infrastructure damage. This information assists in prioritizing rescue and relief operations, assessing the extent of damage, and monitoring recovery progress.
Additionally, the intensity and spatial distribution of this data facilitate the estimation of light pollution, which refers to excessive or misdirected artificial lighting negatively impacting the natural environment and human well-being. Through the analysis of light intensity and spectral characteristics, researchers can assess the extent of light pollution, its ecological impact, and propose measures to reduce energy waste and preserve the night sky. The International Dark-Sky Association, located in Tucson, United States, has estimated that residential outdoor lighting emits approximately 15 million tons of Carbon Dioxide (CO2) annually. This significant release of CO2 contributes to the heat trapped in the atmosphere, ultimately exacerbating global warming and climate change. Therefore, the regular monitoring of light data plays a crucial role in assessing the potential risks associated with global warming and climate change.
In conclusion, night-time light data is a highly valuable tool for monitoring and addressing urban growth, environmental concerns, and light pollution. It enables the identification of areas requiring attention and facilitates the development of specific strategies to mitigate these challenges.
By integrating night-time light data into environmental management efforts, Malaysia can effectively preserve its natural nocturnal environment, safeguard wildlife habitats, and promote sustainable lighting practices, ensuring a better future for both nature and communities.
Just as travellers in the past relied on the stars to guide their journeys, perhaps today we can harness the power of the lights we illuminate to pave our path towards the future.
By Dr. Siti Noratiqah Mohamad Deros
The author is the Operation Manager at The Energy Sphere Satellite Intelligence Hub (TESSAT), Universiti Tenaga Nasional (UNITEN), and may be reached at [email protected]
