HR: 10:20h
AN: A11I-01 INVITED     [PDF]
TI: Boreal Forest Fires - Behavior and Atmospheric Impacts
AU: * Stocks, B J
EM: bstocks@NRCan.gc.ca
AF: Canadian forest Service, 1219 Queen Street East, Sault Ste. Marie, Ont P6A 2E5 Canada
AB: Fire is a natural and essential stand-renewing agent in circumboreal forests, and eliminating fire in this region is neither economically possible nor ecologically desirable. In general, boreal fire is managed on the basis of values-at-risk, with high levels of protection afforded to economically and recreationally important areas, while fire is permitted to burn naturally in many remote areas. Current estimates are that an average of 5-15 million hectares burn annually across the boreal zone, with at least 50% of the area burning in largely unmanaged forest. High-intensity crown fires account for the vast majority of the area burned in the boreal zone, particularly in North America. These fires typically consume 20-30 tonnes/ha of fuel, spread at rates up to 100 m/min, and generate intensity levels (or energy release rates) approaching 100,000 kW/m of fire front. Deep forest floor (organic) layers common to boreal forests contribute significantly to high levels of fuel consumption and assist in the propagation of crown fires. When crown fires are sustained through a peak afternoon burning period, they usually produce towering convection columns that can reach the upper troposphere directly. Numerous boreal fires columns reaching 11-14 kilometres in height have been documented in the fire literature. Given the lower altitude of the tropopause at boreal zone latitudes it is not surprising that some boreal fire columns have been recently reported reaching the lower stratosphere. Current global and regional climate models suggest a significant increase in both the severity and frequency of boreal fires under a changing climate, with potentially major impacts on terrestrial carbon storage and the global carbon budget, as well as hemispheric smoke transport. Modelling convection column dynamics is essential to predicting the future transport and atmospheric impacts of boreal fire smoke, and this science requires a solid understanding of fuel consumption and fire behavior on the ground, presenting a solid opportunity for mutually-beneficial collaboration between atmospheric modelers and the wildland fire research community.
DE: 0315 Biosphere/atmosphere interactions
DE: 1610 Atmosphere (0315, 0325)
DE: 1615 Biogeochemical processes (4805)
SC: Atmospheric Sciences [A]
MN: 2003 Fall Meeting