NOAA readies for satellite gap

The National Oceanic and Atmospheric Administration’s polar satellite program is in danger of extended coverage outages as a replacement satellite is years from operation, but for now, the current crop of satellites are producing amazing imagery.

On Dec. 5, scientists revealed global composite images constructed from nighttime images taken by Suomi National Polar-orbiting Partnership (NPP) satellite, using an instrument called the Visible Infrared Imaging Radiometer Suite (VIIRS), which detects light in a range of wavelengths and the power to observe dim signals like city lights, auroras and wildfires. The new images show what Earth’s cities look like at night, and was assembled from data the satellite acquired in April and October 2012.

“Nothing tells us more about the spread of humans across the Earth than city lights,” said Chris Elvidge, a physical scientist at NOAA. Elvidge has studied nighttime lights data since 1992, with satellite images far less precise than the news ones. “Even after 20 years, I'm always amazed at what city light images show us about human activity.”

The images are part of NOAA’s National Weather Service’s continued exploration of the day-night band and its use in weather forecasting, said Mitch Goldberg, program scientist for NOAA’s Joint Polar Satellite System. “The very high resolution from VIIRS data will take forecasting weather events at night to a much higher level,” he said.

The sensors will help satellites view Earth and weather events at night like they do during the day. The NPP satellite is a converted demonstration satellite that was launched in October 2011 by the Joint Polar Satellite System, a NOAA-led project with NASA’s assistance that aims to replace the polar-orbiting satellites that feed huge amounts of observational data in data models that the scientific agency uses to forecast weather.

The NPP satellite was important in generating data that helped meteorologists accurately forecast Hurricane Sandy.

It orbits the Earth every 102 minutes at about 500 miles above the surface, yet because it was formerly a demonstration satellite, its life expectancy is only about three to five years. Since the JPPS program is not expected to have a fully operational polar-orbiting satellite ready until 2017, some – including NOAA – are looking for solutions to an expected gap in satellite coverage.