2,418 research outputs found
Modeling wildland fire propagation with level set methods
International audienceLevel set methods are versatile and extensible techniques for general front tracking problems, including the practically important problem of predicting the advance of a fire front across expanses of surface vegetation. Given a rule, empirical or otherwise, to specify the rate of advance of an infinitesimal segment of fire front arc normal to itself (i.e., given the fire spread rate as a function of known local parameters relating to topography, vegetation, and meteorology), level set methods harness the well developed mathematical machinery of hyperbolic conservation laws on Eulerian grids to evolve the position of the front in time. Topological challenges associated with the swallowing of islands and the merger of fronts are tractable. The principal goals of this paper are to: collect key results from the two largely distinct scientific literatures of level sets and fire spread; demonstrate the practical value of level set methods to wildland fire modeling through numerical experiments; probe and address current limitations; and propose future directions in the simulation of, and the development of, decision-aiding tools to assess countermeasure options for wildland fires. In addition, we introduce a freely available two-dimensional level set code used to produce the numerical results of this paper and designed to be extensible to more complicated configurations
A review of wildland fire spread modelling, 1990-present 3: Mathematical analogues and simulation models
In recent years, advances in computational power and spatial data analysis
(GIS, remote sensing, etc) have led to an increase in attempts to model the
spread and behvaiour of wildland fires across the landscape. This series of
review papers endeavours to critically and comprehensively review all types of
surface fire spread models developed since 1990. This paper reviews models of a
simulation or mathematical analogue nature. Most simulation models are
implementations of existing empirical or quasi-empirical models and their
primary function is to convert these generally one dimensional models to two
dimensions and then propagate a fire perimeter across a modelled landscape.
Mathematical analogue models are those that are based on some mathematical
conceit (rather than a physical representation of fire spread) that
coincidentally simulates the spread of fire. Other papers in the series review
models of an physical or quasi-physical nature and empirical or quasi-empirical
nature. Many models are extensions or refinements of models developed before
1990. Where this is the case, these models are also discussed but much less
comprehensively.Comment: 20 pages + 9 pages references + 1 page figures. Submitted to the
International Journal of Wildland Fir
Coupled atmosphere-wildland fire modeling with WRF-Fire
We describe the physical model, numerical algorithms, and software structure
of WRF-Fire. WRF-Fire consists of a fire-spread model, implemented by the
level-set method, coupled with the Weather Research and Forecasting model. In
every time step, the fire model inputs the surface wind, which drives the fire,
and outputs the heat flux from the fire into the atmosphere, which in turn
influences the atmosphere. The level-set method allows submesh representation
of the burning region and flexible implementation of various ignition modes.
WRF-Fire is distributed as a part of WRF and it uses the WRF parallel
infrastructure for parallel computing.Comment: Version 3.3, 41 pages, 2 tables, 12 figures. As published in
Discussions, under review for Geoscientific Model Developmen
Assimilation of Perimeter Data and Coupling with Fuel Moisture in a Wildland Fire - Atmosphere DDDAS
We present a methodology to change the state of the Weather Research
Forecasting (WRF) model coupled with the fire spread code SFIRE, based on
Rothermel's formula and the level set method, and with a fuel moisture model.
The fire perimeter in the model changes in response to data while the model is
running. However, the atmosphere state takes time to develop in response to the
forcing by the heat flux from the fire. Therefore, an artificial fire history
is created from an earlier fire perimeter to the new perimeter, and replayed
with the proper heat fluxes to allow the atmosphere state to adjust. The method
is an extension of an earlier method to start the coupled fire model from a
developed fire perimeter rather than an ignition point. The level set method is
also used to identify parameters of the simulation, such as the spread rate and
the fuel moisture. The coupled model is available from openwfm.org, and it
extends the WRF-Fire code in WRF release.Comment: ICCS 2012, 10 pages; corrected some DOI typesetting in the reference
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