Application of fusion remote sensing technology for coal fire identification in the Sikeshu sealed fire area

Taking coal fires in Sikeshu sealed fire area of Zhunnan coal field as the research object, the images of the study area during the period 2006-2020 were selected from the Landsat series, and the vegetation coverage and surface temperature distribution in this area were retrieved by pixel dichotomy and temperature inversion algorithm. The results show that the proportion of low vegetation cover area decreases from 38.6% to 13.9%, and the proportion of vegetation coverage increases from 15.6% to 29.0%. The high temperature area is distributed in a straight line from northeast to southwest. The low temperature area mainly exists in the west-facing depression and the west side of the depression; the maximum temperature of the threshold extraction is 48.62 ℃. 29 SAR images from 2014 to 2019 were selected for SBAS-InSAR analysis, and the regetatio coverage and surface temperature inversion was integrated to determine the location and quantity of the smoke escape channels and air inflltration channels in the sealed fire area. The results show that the number of air escape channels increases from 7 to 68 and the number of air infiltration channels increaes from 58 to 84 between 2014 and 2019. The number of cracks in the whole shows an increasing trend, and the number of flue gas escape channels increases rapidly, and the underground coal fire combustion intensifies.