Extreme fire events are related to previous-year surface moisture conditions in permafrost-underlain larch forests of Siberia

• Published in: Environmental Research Letters
• Main Authors: Matthias Forkel, Kirsten Thonicke, Christian Beer, Wolfgang Cramer, Sergey Bartalev, Christiane Schmullius
• Format: Article in Journal/Newspaper
• Language: English
• Published: IOP Publishing 2012
• Subjects: remote sensing; Baikal region; boreal forest; larch forests; permafrost; soil moisture; Environmental technology. Sanitary engineering; TD1-1066; Environmental sciences; GE1-350; Science; Q; Physics; QC1-999; Siberia
• Online Access: https://doi.org/10.1088/1748-9326/7/4/044021; https://doaj.org/article/30261494052b43e1a46b187d83918b96

Wildfires are a natural and important element in the functioning of boreal forests. However, in some years, fires with extreme spread and severity occur. Such severe fires can degrade the forest, affect human values, emit huge amounts of carbon and aerosols and alter the land surface albedo. Usually, wind, slope and dry air conditions have been recognized as factors determining fire spread. Here we identify surface moisture as an additional important driving factor for the evolution of extreme fire events in the Baikal region. An area of 127 000 km ^2 burned in this region in 2003, a large part of it in regions underlain by permafrost. Analyses of satellite data for 2002–2009 indicate that previous-summer surface moisture is a better predictor for burned area than precipitation anomalies or fire weather indices for larch forests with continuous permafrost. Our analysis advances the understanding of complex interactions between the atmosphere, vegetation and soil, and how coupled mechanisms can lead to extreme events. These findings emphasize the importance of a mechanistic coupling of soil thermodynamics, hydrology, vegetation functioning, and fire activity in Earth system models for projecting climate change impacts over the next century.