New Delhi:
We often get to see the view of our planet Earth as seen from space, thanks to NASA. The US space agency has yet again released beautiful pictures revealing the night view of Earth as seen from space. The new picture also shows how India dazzles during the night time. When you compare this image of 2016 with the one taken in 2012, you will find that India shines more in 2016 than 2012.
NASA’s new global maps of Earth as seen at night provide the clearest and composite view of the patterns of human settlement across the planet.
The satellite images of Earth taken at night are often referred as night lights. For nearly 25 years, these night lights have been a tool for fundamental research and a source of curiosity among the public.
NASA has now released some lovely images of night lights that were observed in 2016 along with a revised version of the 2012 map of different countries in the world including India. The images show how humans have shaped the planet and lit up the darkness.
This before-and-after comparison beautifully explains the night time views of India and surrounding areas.
Such maps are produced by NASA every decade or so. These maps have spawned hundreds of pop-culture uses and dozens of economic, social science and environmental research projects.
The NASA-NOAA Suomi National Polar-orbiting Partnership (NPP) satellite was launched in 2011. Since then, researchers have been analysing night lights data and developing new software and algorithms to make night lights imagery clearer, more accurate and readily available.
Reserachers now plan to provide high-definition views of Earth at night on everyday basis. They are targeting the release of such data to the science community later in 2017.
The main challenge in night time satellite imaging is accounting for the phases of the moon, which constantly varies the amount of light shining on Earth, though in predictable ways.
Likewise, seasonal vegetation, clouds, aerosols, snow and ice cover, and even faint atmospheric emissions (such as airglow and auroras) change the way light is observed in different parts of the world.
Data from all months of each year was used to produce the new maps. The team wrote code that picked the clearest night views each month, ultimately combining moonlight-free and moonlight-corrected data.
Almost all locations on Earth are observed by Suomi NPP at roughly 1:30 pm and 1:30 am (local time) everyday. The planet is observed in vertical 3,000-kilometre strips from pole to pole. Suomi NPP data is freely available to scientists within minutes to hours of acquisition.
Armed with more accurate nighttime environmental products, the NASA team is now automating the processing so that users will be able to view nighttime imagery within hours of acquisition.
This has the potential to aid short-term weather forecasting and disaster response.
