SPECTRAL ANALYSIS OF FLAMING AND NON-FLAMING INFRARED EMITTERS WITH NIGHTTIME VIIRS DATA: PRELIMINARY RESULTS

摘要

Traditional satellite fire detection algorithms report out pixels with enhanced radiance in a single spectral band. In such case, it is impossible to calculate the temperature or source area because the fire radiant emissions are sampled at a single wavelength. Beginning in 2012, our team developed the VIIRS nightfire (VNF) algorithm, which searches for IR emitters in six spectral bands spanning near infrared (NIR), shortwave infrared (SWIR), and midwave infrared (MWIR). The original VNF used dual Planck curve fitting for a hot IR emitter and a cool background. The IR emitter Planck curve was then used the derive the IR emitter's temperature, source size, and radiant heat using physical laws. The analysis assumes that the IR emitters inside the pixel footprint have a constant temperature. Flaming phase combustion tends to dominate resulting temperature, a consequence of the T4 term in the Stefan-Boltzmann Law. Our team has developed methods to resolve two IR emitter phases present in a single pixel. The approach is via triple phase Planck curve fitting for a cool background, and hot flaming phase and an intermediate temperature non-flaming phase, such as smoldering.