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Wildfires negatively affect the atmosphere and ecological environment. The rapid identification of smoke is helpful for early fire detection and positioning, which are significant for fire early warning, fire point tracing, and atmospheric environment monitoring. The purpose of this research is the establishment of a smoke detection framework with which to carry out smoke identification, concentration inversion and the extraction of the smoke concentration center to realize fire source identification and positioning. The spectral characteristics and variation pattern of smoke were first studied and analyzed based on a physical correlation model and laboratory experiments. Moreover, the spectral variation of the vegetation background was measured by the Mahalanobis distance (MD), and MD-based smoke identification and concentration inversion were carried out. Then, the extraction of the smoke concentration center and fire source positioning were realized based on the Laplace operator. Finally, the application and verification of the proposed method were carried out on spaceborne data of forest smoke in Daxing’anling, China, and British Columbia, Canada. The results show that: (1) At the significance level α = 0.1%, the overall accuracy of smoke recognition based on satellite images was 91.30%, and the Kappa coefficient was 81.69%. (2) The retrieved smoke concentration was in line with the visual interpretation results. (3) The fire point location error was 23.05 ± 4.14 m (less than 2 pixels). The results indicate that the proposed MD-based smoke detection model can effectively realize smoke pixel identification and concentration inversion. The proposed smoke concentration center identification method can accurately locate the fire source and provide positioning services to trace the source of wildfires in forest fire emergencies.

The currently used energy methods in spectral emissivity measurement are susceptible to the difference in temperature between the target and the reference blackbody. It is also limited by the state of the observation target and observation. This paper introduces the irradiance condition, while using the correlation between the information of emission energy and reflected energy of the high-temperature target. Based on the principle of radiative transmission and energy conservation, the relationship between the emissivity and bidirectional reflectance factor (BRF) was used to perform the retrieval of emissivity and temperature. An experimental device was designed, and graphite and rock were considered to verify the feasibility of the experimental scheme. The error of emissivity and temperature of both targets were, respectively, less than 5% and 0.5%, due to the Lambertian assumption, and the systematic errors had negligible impact on the retrieval. This verifies that the experimental observation method and scheme is reasonable.