HR: 13:40h
AN: B43E-01    [Abstracts]
TI: Hierarchical Controls of Fire Weather and Fire Climate in the Western United States
AU: * Bartlein, P J
EM: bartlein@uoregon.edu
AF: Univ. Oregon, Dept. Geography, Eugene, OR 97403-1251 United States
AU: Hostetler, S
EM: steve@coas.oregonstate.edu
AF: U.S. Geological Survey, Oregon State Univ. Dept. Geosciences, Corvallis, OR 97333 United States
AU: Shafer, S L
EM: sshafer@usgs.gov
AF: U.S. Geological Survey, 200 SW 35th St., Corvallis, OR 97333 United States
AU: Holman, J O
EM: jholman@uoregon.edu
AF: Univ. Oregon, Dept. Geography, Eugene, OR 97403-1251 United States
AU: Holman, J O
EM: jholman@uoregon.edu
AF: U.S. Geological Survey, Oregon State Univ. Dept. Geosciences, Corvallis, OR 97333 United States
AU: Solomon, A M
EM: Solomon.Allen@epamail.epa.gov
AF: U.S. Environmental Protection Agency, 200 SW 35th St., Corvallis, OR 97333 United States
AB: The incidence of wildfire in the western United States is governed by climatological, meteorological, and ecological controls that operate across a range of spatial and temporal scales, from hemispheric to landscape, and from decadal (and longer) to diurnal. These controls are responsible for fire weather (i.e., the conditions responsible for the ignition, spread, and suppression of individual fires) and fire climate (i.e., the conditions responsible for the severity of a particular fire season). Interannual, seasonal, and monthly anomalies of Pacific Ocean SSTs and North American land-surface conditions produce anomalous components of atmospheric circulation, and variations in airmass distributions, moisture flux, large-scale vertical motions and precipitation fields on monthly-to-daily time scales. The synoptic situations that result from these circulation configurations determine the meteorological conditions that are directly responsible for the outbreak of fires on daily-to-diurnal time scales, such as the surface water- and energy-balances, atmospheric stability, lightning and wind. Fire outbreaks over the West often form a coherent pattern associated with the temporal and spatial dynamics of circulation. The severity of a particular fire season is largely determined by the integration across time spans of seasons to months of the water-balance related variables described above, which determine soil-moisture status, as well as by the condition of the vegetation, which determines fuel load and flammability. We are investigating these hierarchal controls of wildfires using a combination of observations (including monthly-to-decadal averages of atmospheric circulation indices and surface temperature, precipitation and soil moisture-related variables), reanalysis data sets, and simulations using a GCM/regional climate model/dynamic global vegetation model combination.
UR: http://geography.uoregon.edu/envchange/
DE: 3329 Mesoscale meteorology
DE: 1851 Plant ecology
DE: 1615 Biogeochemical processes (4805)
DE: 1620 Climate dynamics (3309)
DE: 0400 Biogeosciences
SC: Biogeosciences [B]
MN: 2004 AGU Fall Meeting