City skylines are always beautiful at night. The beauty of planet Earth at night can be enjoyed from crisp images captured by NASA, called night light maps, and recently released by the space agency.
The latest NASA Earth night images of 2016 showcase concrete patterns of human settlement.
Compiled from satellite views, NASA's global maps for 2016 stand out for clarity and accuracy compared with similar images that have been around for 25 years. Previously, these images were compiled once in 10 years.
In early April, NASA released a global map of night lights in 2016 based on satellite observations. It also released an updated version of the 2012 night light map.
The NASA images of cities at night will be serving a scientific purpose besides the conventional use as a tool for studying cities. The night images are being used in research projects of economics, social science, and the environment.
In the words of the space agency, the night maps have been offering a "gee-whiz curiosity for the public and a tool for fundamental research for nearly 25 years."
Earth Night Maps To Help In Weather Forecasting
The images of 2016 express better clarity and accuracy compared with the relatively vague images of 2012. It is an advancement of the globe being lit up and a bigger contribution of humans in shaping up the earth.
In the time to come, the satellite images of night Earth referred to as "night lights" will see greater frequency as NASA will be launching more images. This will also help in shoring up weather forecasting, improving responses to natural disasters, and studying the effects of war on the planet.
NASA Plans Rapid Update Of Earth Night Images
Determined to optimize the potential of NASA night lights, the space agency is planning rapid updates, breaking the 10-year interval.
Already, a team led by Miguel Román, an earth scientist at Goddard Space Flight Center of NASA, is at work to develop new software to attain more clarity and accuracy for the night lights. The plan is to produce high-definition views of Earth at night.
Since the 2011 launch of NASA's NOAA Suomi National Polar-orbiting Partnership or NPP satellite, Román and team have been analyzing night lights data and developing new software and algorithms to make images brighter, clearer, and more accurate.
Obstacles In Mapping Light Radiation
NASA coped with many challenges in preparing the night images as the quantum of light shining on Earth varies constantly and predictably.
NASA examined how light is radiated, reflected and scattered by land, atmospheric, and ocean surfaces.
Challenging Task Made Easy By New Technology
Normally, it is hard to make an image at night as constantly shifting light is a problem. Then the changing phases of the moon also affects light patterns.
There are also factors affecting the path of light and their visibility in various parts of the world such as vegetation, clouds, aerosols, ice cover, and feeble emissions like auroras.
However, things have changed now with the advent of new technology. NASA has an able tool in the Visible Infrared Imaging Radiometer Suite or VIIRS from the Suomi NPP weather satellite.
VIIRS boasts of the capability to detect light reflected from Earth's surface and atmosphere in 22 wavelengths. It also excels as the first satellite instrument that takes quantitative measurements of emitted and reflected light.
The measurements can determine the intensity and source of light over a number of years. In September 2016, VIIRS mapped the power outages in southeast America and the Caribbean after Hurricane Matthew hit the continent.
"Thanks to VIIRS, we can now monitor short-term changes caused by disturbances in power delivery, such as conflict, storms, earthquakes and brownouts," said NASA scientist Román.