CO and CH4 atmospheric trends from dense multi-point forest fires around the city of Chongqing using spaceborne spectrometer data

Abstract

Forest fires greatly impact the global terrestrial ecology and atmospheric environment. It is important to improve fire prediction mechanisms and track fire trends. This study evaluates using spaceborne spectrometers (Sentinel-5P TROPOMI and Aqua AIRS) to track atmospheric CO and CH4 changes caused by more than a dozen forest fires around the main urban area of Chongqing, China. These forest fires consisted of dense, multi-point, small-scale outbreaks over a short period (August 17–26, 2022). All the fires were near human living areas, leading to relatively complex atmospheric trends. We obtained the spatial distribution of CO and CH4 and analysed the forest fires' exact occurrence and quenching time at each fire location. Concentration gradients of the CO column are consistent with the rise and fall of the fires observed at all fire points. Large CO plumes from different fire locations observed on August 21, and 22 have concentrations exceeding 0.07 molecules/m2. The average CO concentration data at nine ignition points are summed to reflect the temporal trend of CO in the atmosphere over the entire region. The CO2 column range estimated from the CO column was 0.16–0.63 molecules/m2 on August 22. We also tracked and analysed the atmospheric trend of methane concentration during the fire. Consequently, based on satellite data, tracking the temporal trends of CO and CH4 in the atmosphere caused by dense forest fires in a complex environment is feasible.