HR: 0800h
AN: B41B-0118    [Abstracts]
TI: Characterizing Wildfire Regimes and Risk in the USA
AU: * Malamud, B D
EM: bruce@malamud.com
AF: Environmental Monitoring and Modelling Research Group, Department of Geography, King's College London, Strand, London, WC2R 2LS United Kingdom
AU: * Malamud, B D
EM: bruce@malamud.com
AF: Oxford Centre for Industrial and Applied Mathematics, Mathematical Institute, 24--29 St. Giles', Oxford, OX1 3LB United Kingdom
AU: Millington, J D
EM: james.millington@kcl.ac.uk
AF: Environmental Monitoring and Modelling Research Group, Department of Geography, King's College London, Strand, London, WC2R 2LS United Kingdom
AU: Perry, G L
EM: george.perry@auckland.ac.nz
AF: School of Geography and Environmental Science, University of Auckland, Tamaki Campus, Private Bag 92019, Auckland, 1020 New Zealand
AB: Over the last decade, high profile wildfires have resulted in numerous fatalities and loss of infrastructure. Wildfires also have a significant impact on climate and ecosystems, with recent authors emphasizing the need for regional-level examinations of wildfire-regime dynamics and change, and the factors driving them. With implications for hazard management, climate studies, and ecosystem research, there is therefore significant interest in appropriate analysis of historical wildfire databases. Insightful studies using wildfire database statistics exist, but are often hampered by the low spatial and/or temporal resolution of their datasets. In this paper, we use a high-resolution dataset consisting of 88,855 USFS wildfires over the time period 1970--2000, and consider wildfire occurrence across the conterminous USA as a function of ecoregion (land units classified by climate, vegetation, and topography), ignition source (anthropogenic vs. lightning), and decade (1970--1979, 1980--1989, 1990--1999). We find that for the conterminous USA (a) wildfires exhibit robust frequency-area power-law behavior in 17 different ecoregions, (b) normalized power-law exponents may be used to compare the scaling of wildfire burned areas between regions, (c) power-law exponents change systematically from east to west, (d) wildfires in 75% of the conterminous USA (particularly the east) have higher power-law exponents for anthropogenic vs.\ lightning ignition sources, and (e) recurrence intervals for wildfires of a given burned area or larger for each ecoregion can be assessed, allowing for the classification of wildfire regimes for probabilistic hazard estimation in the same vein as is now used for earthquakes. By examining wildfire statistics in a spatially and temporally explicit manner, we are able to present resultant wildfire regime summary statistics and conclusions, along with a probabilistic hazard assessment of wildfire risk at the ecoregion division level across the conterminous USA.
DE: 9350 North America
DE: 6300 POLICY SCIENCES
DE: 3200 MATHEMATICAL GEOPHYSICS (New field)
DE: 0400 Biogeosciences
SC: Biogeosciences [B]
MN: 2004 AGU Fall Meeting