Interpreting Temporal Changes of Atmospheric CO 2 Over Fire Affected Regions Based on GOSAT Observations

The carbon dioxide (CO 2 ) emissions released from biomass burning significantly affect the temporal variations of atmospheric CO 2 concentrations. Based on a long-term (July 2009–June 2015) retrieved data sets by the greenhouse gases observing satellite (GOSAT), the seasonal cycle and interannual variations of column-averaged volume mixing ratios of atmospheric carbon dioxide (XCO 2 ) in four fire affected continental regions were analyzed. The results showed that Northern Africa (NA) had the largest seasonal variations after removing its regional trend of XCO 2 with peak-to-peak amplitude of 6.2 ppm within the year, higher than central South America (CSA) (2.4 ppm), Southern Africa (SA) (3.8 ppm), and Australia (1.7 ppm). The detrended regional XCO 2 ( $\triangle $ XCO 2 ) was found to be positively correlated with the fire CO 2 emissions during the fire activity period but with different seasonal variabilities. NA recorded the largest change of seasonal variations of $\triangle $ XCO 2 with a total of 12.8 ppm during fire seasons, higher than CSA, SA, and Australia with 5.4, 6.7, and 2.2 ppm, respectively. During the fire episode, the positive $\triangle $ XCO 2 was noticed during June–November in CSA, December to next June in NA, and May–November in SA. The Pearson correlation coefficients between the variations of $\triangle $ XCO 2 and fire CO 2 emissions achieved the best correlations in SA ( $R = 0.77$ and $p ). This letter revealed that fire CO 2 emissions and GOSAT XCO 2 presented consistent seasonal variations.