A simulation of probabilistic wildfire risk components for the continental United States |
| |
Authors: | Mark A Finney Charles W McHugh Isaac C Grenfell Karin L Riley Karen C Short |
| |
Institution: | (1) USDA Forest Service, Missoula Fire Sciences Laboratory, 5775 Highway 10 West, Missoula, MT 59808, USA;(2) Systems for Environmental Management, PO Box 8868, Missoula, MT 59802, USA |
| |
Abstract: | This simulation research was conducted in order to develop a large-fire risk assessment system for the contiguous land area
of the United States. The modeling system was applied to each of 134 Fire Planning Units (FPUs) to estimate burn probabilities
and fire size distributions. To obtain stable estimates of these quantities, fire ignition and growth was simulated for 10,000
to 50,000 “years” of artificial weather. The fire growth simulations, when run repeatedly with different weather and ignition
locations, produce burn probabilities and fire behavior distributions at each landscape location (e.g., number of times a “cell” burns at a given intensity divided by the total years). The artificial weather was generated for
each land unit using (1) a fire danger rating index known as the Energy Release Component (ERC) which is a proxy for fuel
moisture contents, (2) a time-series analysis of ERC to represent daily and seasonal variability, and (3) distributions of
wind speed and direction from weather records. Large fire occurrence was stochastically modeled based on historical relationships
to ERC. The simulations also required spatial data on fuel structure and topography which were acquired from the LANDFIRE
project (). Fire suppression effects were represented by a statistical model that yields a probability of fire containment based on
independent predictors of fire growth rates and fuel type. The simulated burn probabilities were comparable to observed patterns
across the U.S. over the range of four orders of magnitude, generally falling within a factor of 3 or 4 of historical estimates.
Close agreement between simulated and historical fire size distributions suggest that fire sizes are determined by the joint
distributions of spatial opportunities for fire growth (dependent on fuels and ignition location) and the temporal opportunities
produced by conducive weather sequences. The research demonstrates a practical approach to using fire simulations at very
broad scales for purposes of operational planning and perhaps ecological research. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|