Mikhail Zhizhin and Feng Chi Hsu

National Geophysical Data Center NOAA and CIRES University of Colorado, Boulder

Title: Real-time mapping of light sources on the night side of the Earth using NPP satellite sensors

Abstract

Night-time images from the NPP satellite VIIRS scanning radiometer in
visible and infrared spectral bands provide invaluable data for
real-time detection of natural and technological lights and combustion
sources on the surface of the Earth, such as city lights, forest
fires, gas flares, steel mills or active volcanoes. Temperature and
radiative power of the night time lights can be estimated by fitting
of a Planck black-body spectral curve to the observed radiances of all
VIIRS infrared M-channels and visible day-night band. VIIRS instrument
is most sensitive to the IR sources with temperature range from 800 to
2000 degrees K. This method can discriminate low temperature sources
such as volcanoes and forest fires from the high temperature gas
flares with 300 m average location error. Global real-time mapping of
the IR sources on the Earth requires correction of the images for bow
tie effect and filtering of the false detections resulting from sensor
bombardment by the cosmic rays, especially at the aurora rings and at
the South Atlantic anomaly. False detections can be removed by
collocation of the observed bright spots in multiple channels. After
geometry correction and denoising, thousands of IR point sources and
the night time lights are daily mapped on Google Earth and listed in a
database table. Computational problems of spatio-temporal
classification and superresulution imaging of the point light sources
on the night side of the Earth are similar to ones faced by
astronomers.