Boreal blazes

The past decade includes some of the most extensive boreal forest fires in the historical record. Warming temperatures, changing precipitation patterns, the desiccation of thick organic soil layers, and increased ignition from lightning all contribute to a combustive combination. Smoke aerosols travel thousands of kilometers, before blanketing the surfaces on which they fall, such as the Juneau Icefield. However, many aerosols found in smoke plumes are also produced by other processes and therefore can be ambiguous indicators of fire activity. Here, we use the monosaccharide anhydrides levoglucosan, mannosan, and galactosan as specific indicators of biomass burning to unambiguously demonstrate that fire aerosols reach the Juneau Icefield and are integrated into the snowpack. Back trajectories and satellite observations demonstrate that smoke plumes originating in central Alaska and eastern Siberia affect the Juneau Icefield. These regional sources of fire differ from other combustion aerosols deposited on the Juneau Icefield, such as black carbon, that originate from local fossil fuel burning. Ratios of levoglucosan/mannosan (L/M) and levoglucosan/(mannosan + galactosan) (L/(M + G)) demonstrate that while the majority of fire aerosols reaching the Juneau Icefield originate from softwood burning, grasslands and hardwood forests are also sources. The presence of these hardwoods suggests that fire aerosols may reach the Juneau Icefield from locations as far away as East Asia

Aerosol · Atmospheric sciences · Biomass burning · Boreal · Climatology · Ecosystem · Fire regime · Geography · Ice field · Levoglucosan · Meteorology · Physical geography · Taiga · Climate change and permafrost · Cryospheric studies and observations · Environmental Science · Fire effects on ecosystems · Ecology · Forestry · Geology

• High-latitude fire activity of recent decades derived from microscopic charcoal and black carbon in Greenland ice cores

  Open Access•Sandra O Brugger, Nathan J Chellman et al.•The Holocene•2022

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• Long-Term Fire Regime Estimated from Soil Charcoal in Coastal Temperate Rainforests

  Open Access•K Lertzman, Daniel G Gavin et al.•Conservation Ecology•2002

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