Study on the influence of coal fire on the temporal and spatial distribution of CO2 and CH4 gas emissions

In order to study the impact of gas released from coal fire combustion on the spatial–temporal distribution of CO2 and CH4 and other greenhouse gas emissions, the impact of regional coal fire on CO2 and CH4 emission flux was comprehensively evaluated using Landsat 8 and GOSAT satellite data in Xinjiang. In addition, typical fire areas are selected, a single-channel algorithm is used to invert the surface temperature of the coal field, the spatial distribution of the coal fire area is extracted by setting the threshold, and the influence law of CO2 and CH4 emissions in the typical fire area is accurately analyzed. The results show that during 2017–2018, CO2 and CH4 emissions in Xinjiang were generally dispersed and locally concentrated, while CO2-O and CH4-O were at low levels in most regions, fluctuating in the ranges of 0.01 ~ 0.14 g·m−2·day−1 and 0.001 ~ 0.003 g·m−2·day−1, respectively. However, the emission intensity of CO2-O and CH4-O in coal fire concentrated areas is higher, which are 1.6 ~ 3.8 g·m−2 day−1 and 0.013 ~ 0.026 g·m−2·day−1, respectively. CO2-F and CH4-ag have similar laws. The fire area of Daquan Lake is scattered, and there are four areas with the surface temperature over 35 °C: A, B, C, and D, respectively. The Sandaoba fire area is more concentrated, and only two areas are E and F when the surface temperature exceeds 35 °C. CO2 and CH4 released by burning in Daquan Lake and Sandaoba fire areas increased CO2-F and CH4-ag by 2.08 and 0.89 times, respectively. The results provide a reference for coal fire control and carbon emission reduction.