Nightfire: Sub-pixel Pyrometry of Nighttime Combustion Sources with Suomi NPP and Landsat 8

Abstract:

The Earth Observation Group at NOAA’s National Geophysical Data Center has an active program on nocturnal remote sensing of combustion sources. Spectral bands designed for daytime imaging are particularly useful for detecting and characterizing fires, flares and industrial heat sources. By measuring combustion source emitted radiances across a range of wavelengths, the nightfire algorithm is able to model the Planck curve, which makes it possible to estimate temperature, size, and radiant heat of subpixel combustion sources. The algorithm fits two Planck curves for the sub-pixel fire and the background in a detected pixel and estimates the fire temperature, area and radiative power. Combining one day of data from the Suomi NPP VIIRS sensor, the Nightfire algorithm can detect and characterize more than 10,000 fires on the night side of the Earth with temperatures ranging from 500 K to 2,500 K and active burn areas down to several square meters. The temperature histogram for the detected fires has two distinct peaks discriminating gas flares from biomass burning. The Nightfire algorithm has been successfully applied to nighttime scenes from the Landsat 8 OLI sensor which has 30 m spatial resolution and higher dynamic range than VIIRS. Global Nightfire detection products are produced daily and are available from the NOAA NGDC web site.