HR: 14:25h
AN: B43E-04    [Abstracts]
TI: A Long Term Perspective on Decadal Variability in Climate and Wildfire in the Western United States
AU: * Westerling, A L
EM: leroy@ucsd.edu
AF: Scripps Institution of Oceanography, 9500 Gilman Drive, La Jolla, CA 92093-0224 United States
AU: Swetnam, T W
EM: tswetnam@ltrr.arizona.edu
AF: Laboratory of Tree-Ring Research, 105 West Stadium, Tucson, AZ 85721 United States
AB: Despite progress in reconstructing the western United States' paleo- fire and climate regimes, placing recent fire seasons into the context of past variability is difficult. Management practices have altered ecosystems, and modern records and paleo reconstructions of wildfire seldom overlap. Recent work helped to bridge that gap, using statistical models trained on 20th century fire and drought histories (1916 to 1978) to successfully reproduce a reconstruction of annual wildfire extent derived from a fire scar network for the U.S. Southwest for 1701 to 1900. We found that managed wildfire regimes still contained strong climate signals similar to paleofire reconstructions. Moreover, El Nino-Southern Oscillation and Pacific Decadal Oscillation patterns appeared to modulate western U.S. fire activity. Using Cook et al.'s newly available drought reconstructions for North America, this analysis now extends to a minimum of 1000 years the period covered by our statistical reconstruction of western U.S. wildfire. We analyze the decadal variability in reconstructed fire regimes over this longer period, and compare the results to available ENSO and PDO reconstructions. The validation of statistical reconstructions of wildfire area burned against fire scar networks is expanded to include sites in California, the Pacific Northwest, and Rocky Mountains. We extend our statistical reconstruction through 2003 and compare the recent increase in observed annual area burned to the increases in both modeled area burned and the land area protected against wildfires in the western United States since the 1970s. Based on this analysis, we place the recent very active fire seasons experienced in the West into the perspective of the past 1000 years of climate variability, and demonstrate an application of long-term climate-fire relationships to budgeting for fire suppression in the USDA Forest Service.
DE: 3344 Paleoclimatology
DE: 4215 Climate and interannual variability (3309)
DE: 2447 Modeling and forecasting
DE: 1833 Hydroclimatology
DE: 0315 Biosphere/atmosphere interactions
SC: Biogeosciences [B]
MN: 2004 AGU Fall Meeting