Quantification of wildfires in North American permafrost domain, based on the MODIS Fire product

• Main Author: Malaj, Milot
• Format: Master Thesis
• Language: Norwegian Bokmål
• Published: 2023
• Subjects: Canada; permafrost; Alaska
• Online Access: http://hdl.handle.net/10852/103800

A number of studies have shown that the boreal forest in North America has experienced a nearly two-fold increase in burned area over the past 60 years, with a corresponding rise in the number of large fires. Permafrost is the dominant ground cover for most of the boreal forest, and forested areas experience greater fire impacts that may decrease permafrost by up to 9-16% by 2100. Modern fire regimes rely on remotely sensed satellite data, including the active fire product from the Moderate Resolution Imaging Spectrometer (MODIS), which has been gathering data since 2000. This study uses the MODIS Active Fire product to quantify the area that experienced fires in permafrost areas, covering a study area between 50 and 70 degrees in North America divided into four subregions, over a 20-year period from 2001 to 2021. The results show that more than 75% of fires occur in central and western Canada, compared to 20% in Alaska and only 5% in Quebec and the Labrador Peninsula. Furthermore, the results indicate that fires occur in all types of permafrost, regardless of ground type, where Alaska has the highest number of fires occurring on permafrost ground, with 96% of all fires occurring in that region. Fires are highly influenced by climate as it determines the tree line of the boreal forest. Additional spatial distribution analyses support these findings. The study also examines trends in the spatial and temporal distribution of fires and finds that 20 years is a short period for analysis, given the significant variation in fire occurrence between years. Finally, the study concludes that while the active fire product has limitations, it is a valuable tool when used in conjunction with other sources of wildfire information such as the Burned Area product and Fire Radiative Power (FRP), as well as other wildfire databases prior to the year 2000. A number of studies have shown that the boreal forest in North America has experienced a nearly two-fold increase in burned area over the past 60 years, with a corresponding ...