Temporal and spatial analysis of vegetation fire activity in the circum-Arctic during 2001-2020

Vegetation fires become the concern worldwide due to their substantial impacts on climate and environment, and in particular in the circum-Arctic. Assessing vegetation fires and associated emissions and causes can improve understanding of fire regime and provide helpful information for vegetation fires solution. In this study, satellitebased vegetation fires and emissions during 2001-2020 were investigated and contributions of different types of fires were analyzed. Furthermore, climate anomalies related to extreme vegetation fires were explored. The main results showed that the region south of the Arctic circle (50 degrees N-67 degrees N) experienced a greater number of vegetation fires compared to the Arctic (north of 67 degrees N). During 2001-2020, interannual variability of vegetation fires between 50 degrees N and 67 degrees N appeared to be decreasing while emissions (including carbon, dry matter, PM2.5, and BC) appeared to be increasing overall, which were contributed by the increasing summer boreal forest fires in this region largely. In the Arctic, vegetation fires and emissions increased in recent years distinctly, and those were dominated by the summer forest fires. Spatially, large increases of vegetation fires were located in the eastern Siberia and northern North America while large decreases were located in the northwestern Eurasia mainly. Additionally, in the Arctic, the unprecedented vegetation fires were observed in the eastern Siberia and Alaska in 2019 and in the eastern Siberia in 2020, which could be attributed to high pressure, high near-surface temperature, and low air moisture anomalies. Meanwhile, obvious anticyclonic anomalies in Alaska in 2019 and in the eastern Siberia in 2020 and cyclonic anomalies in the western Siberia in 2019, also played an important role on fire occurrences making drier conditions.