Ask Weather Guys: Do the weather satellites see the holiday lights? | State and territory
A: Certain weather satellite instruments may see increased illumination of cities during Christmas and Ramadan.
The joint mission of NASA and the National Oceanic and Atmospheric Administration (NOAA), known as the Finland NPP (named after Verner Finland, a professor at UW-Madison known as the father of satellite meteorology), carries an instrument called the Visible Infrared Imaging Radiometer Suite. (ABOVE).
The VIIRS contains sensors in the twilight known as the “day-night band” (DNB), which detect light at different wavelengths from green to near-infrared. Scientists use DNB to monitor relatively dim signals such as northern lights, forest fires and reflected moonlight. Clouds can be seen at night thanks to the moonlight reflected in space. Wildfires can often be detected before other methods detect fires. DNB can also monitor the movement and size of wildfires.
Northern lights are rarely seen in the latitudes of Wisconsin, but DNB detects them almost every night. DNB also sees lightning and light emitted by cities.
DNB does not see light from individual homes, but can measure the net impact across the city. Scientists have used computer algorithms to track when and how brightly cities illuminate the night sky. Scientists have measured the intensity of light coming from cities before Thanksgiving and then compared it to light measured a week or two before Christmas.
During that period, light intensity increased by 30–50% in the suburbs and suburbs of large cities. In the city center, the lights brightened by 20-30%. In some cities in the Middle East, during Ramadan, the night lights were more than 50% brighter than during the rest of the year.
Steve Ackerman and Jonathan Martin, professors in the Department of Atmospheric and Marine Sciences at UW-Madison, will be guests on WHA Radio (970 AM) at 11:45 a.m. on the last Monday of each month. Send them your questions to [email protected] or [email protected].
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