NASA's new night images of Earth could have real time applications

This composite image from the NASA-NOAA Suomi National Polar-orbiting Partnership (NPP) satellite shows the Earth at night. Photo from NASA

NASA has just released the clearest images ever produced of Earth at night.

These “night lights” images have become a staple of NASA over the past 25 years — the last such image was released in 2012. Until now, the time between such new images has been years, but NASA is hoping that data will soon be available daily.

In 2011, NASA launched the NASA-NOAA Suomi National Polar-orbiting Partnership (NPP) satellite, which carries a Visible Infrared Imaging Radiometer Suite (VIIRS), an instrument that detects photons of light reflected from the Earth’s surface and atmosphere. Since then, a team led by scientist Miguel Román has been working with the satellite, developing new software and algorithms that will make night images not only clearer but also immediately available.

The increased clarity of the images is already a reality. The team accounted for the phases of the moon to photograph the Earth on the clearest nights of each month. They also considered other factors like seasonal vegetation, clouds, aerosols, snow and ice cover, and faint atmospheric emissions like airglow and auroras to create the clearest images possible. The result is a spectacular new composite map created from images taken in 2016, as well as an updated version of the 2012 map.

Three composite images published to NASA’s website reveal full-hemisphere views of the Earth at night, with moonlight and cloud cover added for aesthetic effect.

Román’s team is now working to automate the process so that new data can be made available to the public within hours of recording it. Once in place, NASA says this technology could aid in short-term weather forecasting and disaster response.

“Thanks to VIIRS, we can now monitor short-term changes caused by disturbances in power delivery, such as conflict, storms, earthquakes and brownouts,” Román said in a press release. “We can monitor cyclical changes driven by reoccurring human activities such as holiday lighting and seasonal migrations. We can also monitor gradual changes driven by urbanization, out-migration, economic changes, and electrification. The fact that we can track all these different aspects at the heart of what defines a city is simply mind-boggling.”