Journal articles on the topic 'Fire-atmosphere'
To see the other types of publications on this topic, follow the link: Fire-atmosphere.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Fire-atmosphere.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Peace, Mika, Trent Mattner, Graham Mills, Jeffrey Kepert, and Lachlan McCaw. "Fire-Modified Meteorology in a Coupled Fire–Atmosphere Model." Journal of Applied Meteorology and Climatology 54, no. 3 (March 2015): 704–20. http://dx.doi.org/10.1175/jamc-d-14-0063.1.
Full textAbstract:
AbstractThe coupled fire–atmosphere model consisting of the Weather and Forecasting (WRF) Model coupled with the fire-spread model (SFIRE) module has been used to simulate a bushfire at D’Estrees Bay on Kangaroo Island, South Australia, in December 2007. Initial conditions for the simulations were provided by two global analyses: the GFS operational analysis and ERA-Interim. For each NWP initialization, the simulations were run with and without feedback from the fire to the atmospheric model. The focus of this study was examining how the energy fluxes from the simulated fire modified the local meteorological environment. With feedback enabled, the propagation speed of the sea-breeze frontal line was faster and vertical motion in the frontal zone was enhanced. For one of the initial conditions with feedback on, a vortex developed adjacent to the head fire and remained present for over 5 h of simulation time. The vortex was not present without fire–atmosphere feedback. The results show that the energy fluxes released by a fire can effect significant changes on the surrounding mesoscale atmosphere. This has implications for the appropriate use of weather parameters extracted from NWP and used in prediction for fire operations. These meteorological modifications also have implications for anticipating likely fire behavior.
2
Simpson, C. C., J. J. Sharples, and J. P. Evans. "Resolving vorticity-driven lateral fire spread using the WRF-Fire coupled atmosphere–fire numerical model." Natural Hazards and Earth System Sciences 14, no. 9 (September 5, 2014): 2359–71. http://dx.doi.org/10.5194/nhess-14-2359-2014.
Full textAbstract:
Abstract. Vorticity-driven lateral fire spread (VLS) is a form of dynamic fire behaviour, during which a wildland fire spreads rapidly across a steep leeward slope in a direction approximately transverse to the background winds. VLS is often accompanied by a downwind extension of the active flaming region and intense pyro-convection. In this study, the WRF-Fire (WRF stands for Weather Research and Forecasting) coupled atmosphere–fire model is used to examine the sensitivity of resolving VLS to both the horizontal and vertical grid spacing, and the fire-to-atmosphere coupling from within the model framework. The atmospheric horizontal and vertical grid spacing are varied between 25 and 90 m, and the fire-to-atmosphere coupling is either enabled or disabled. At high spatial resolutions, the inclusion of fire-to-atmosphere coupling increases the upslope and lateral rate of spread by factors of up to 2.7 and 9.5, respectively. This increase in the upslope and lateral rate of spread diminishes at coarser spatial resolutions, and VLS is not modelled for a horizontal and vertical grid spacing of 90 m. The lateral fire spread is driven by fire whirls formed due to an interaction between the background winds and the vertical circulation generated at the flank of the fire front as part of the pyro-convective updraft. The laterally advancing fire fronts become the dominant contributors to the extreme pyro-convection. The results presented in this study demonstrate that both high spatial resolution and two-way atmosphere–fire coupling are required to model VLS with WRF-Fire.
3
Simpson, C. C., J. J. Sharples, and J. P. Evans. "Resolving vorticity-driven lateral fire spread using the WRF-Fire coupled atmosphere-fire numerical model." Natural Hazards and Earth System Sciences Discussions 2, no. 5 (May 16, 2014): 3499–531. http://dx.doi.org/10.5194/nhessd-2-3499-2014.
Full textAbstract:
Abstract. Fire channelling is a form of dynamic fire behaviour, during which a wildland fire spreads rapidly across a steep lee-facing slope in a direction transverse to the background winds, and is often accompanied by a downwind extension of the active flaming region and extreme pyro-convection. Recent work using the WRF-Fire coupled atmosphere-fire model has demonstrated that fire channelling can be characterised as vorticity-driven lateral fire spread (VDLS). In this study, 16 simulations are conducted using WRF-Fire to examine the sensitivity of resolving VDLS to spatial resolution and atmosphere-fire coupling within the WRF-Fire model framework. The horizontal grid spacing is varied between 25 and 90 m, and the two-way atmosphere-fire coupling is either enabled or disabled. At high spatial resolution, the atmosphere-fire coupling increases the peak uphill and lateral spread rate by a factor of up to 2.7 and 9.5. The enhancement of the uphill and lateral spread rate diminishes at coarser spatial resolution, and VDLS is not modelled for a horizontal grid spacing of 90 m. The laterally spreading fire fronts become the dominant contributors of the extreme pyro-convection. The resolved fire-induced vortices responsible for driving the lateral spread in the coupled simulations have non-zero vorticity along each unit vector direction, and develop due to an interaction between the background winds and vertical return circulations generated at the flank of the fire front as part of the pyro-convective updraft. The results presented in this study demonstrate that both high spatial resolution and two-way atmosphere-fire coupling are required to reproduce VDLS within the current WRF-Fire model framework.
4
Peace, Mika, Trent Mattner, Graham Mills, Jeffrey Kepert, and Lachlan McCaw. "Coupled Fire–Atmosphere Simulations of the Rocky River Fire Using WRF-SFIRE." Journal of Applied Meteorology and Climatology 55, no. 5 (May 2016): 1151–68. http://dx.doi.org/10.1175/jamc-d-15-0157.1.
Full textAbstract:
AbstractThe coupled atmosphere–fire spread model “WRF-SFIRE” has been used to simulate a fire where extreme fire behavior was observed. Tall flames and a dense convective smoke column were features of the fire as it burned rapidly up the Rocky River gully on Kangaroo Island, South Australia. WRF-SFIRE simulations of the event show a number of interesting dynamical processes resulting from fire–atmosphere feedback, including the following: fire spread was sensitive to small changes in mean wind direction; fire perimeter was affected by wind convergence resulting from interactions between the fire, atmosphere, and local topography; and the fire plume mixed high-momentum air from above a strong subsidence inversion. At 1-min intervals, output from the simulations showed fire spread exhibiting fast and slow pulses. These pulses occurred coincident with the passage of mesoscale convective (Rayleigh–Bénard) cells in the planetary boundary layer. Simulations show that feedback between the fire and atmosphere may have contributed to the observed extreme fire behavior. The findings raise questions as to the appropriate information to include in meteorological forecasts for fires as well as future use of coupled and uncoupled fire simulation models in both operational and research settings.
5
Goodrick, Scott L. "Special Issue Fire and the Atmosphere." Atmosphere 12, no. 1 (January 5, 2021): 66. http://dx.doi.org/10.3390/atmos12010066.
Full text
6
Fardell, P. J., Janet M. Murrell, and J. V. Murrell. "Chemical ?fingerprint? studies of fire atmosphere." Fire and Materials 10, no. 1 (March 1986): 21–28. http://dx.doi.org/10.1002/fam.810100105.
Full text
7
Mandel, J., J. D. Beezley, and A. K. Kochanski. "Coupled atmosphere-wildland fire modeling with WRF-Fire version 3.3." Geoscientific Model Development Discussions 4, no. 1 (March 9, 2011): 497–545. http://dx.doi.org/10.5194/gmdd-4-497-2011.
Full textAbstract:
Abstract. 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 kinds of ignition. WRF-Fire is distributed as a part of WRF and it uses the WRF parallel infrastructure for parallel computing.
8
Dahl, Nathan, Haidong Xue, Xiaolin Hu, and Ming Xue. "Coupled fire–atmosphere modeling of wildland fire spread using DEVS-FIRE and ARPS." Natural Hazards 77, no. 2 (February 8, 2015): 1013–35. http://dx.doi.org/10.1007/s11069-015-1640-y.
Full text
9
Clark, Terry L., Janice Coen, and Don Latham. "Description of a coupled atmosphere - fire model." International Journal of Wildland Fire 13, no. 1 (2004): 49. http://dx.doi.org/10.1071/wf03043.
Full textAbstract:
This paper describes a coupled fire–atmosphere model that uses a sophisticated high-resolution non-hydrostatic numerical mesoscale model to predict the local winds which are then used as input to the prediction of fire spread. The heat and moisture fluxes from the fire are then fed back to the dynamics, allowing the fire to influence its own mesoscale winds that in turn affect the fire behavior. This model is viewed as a research model and as such requires a fireline propagation scheme that systematically converges with increasing spatial and temporal resolution. To achieve this, a local contour advection scheme was developed to track the fireline using four tracer particles per fuel cell, which define the area of burning fuel. Using the dynamically predicted winds along with the terrain slope and fuel characteristics, algorithms from the BEHAVE system are used to predict the spread rates. A mass loss rate calculation, based on results of the BURNUP fuel burnout model, is used to treat heat exchange between the fire and atmosphere. Tests were conducted with the uncoupled model to test the fire-spread algorithm under specified wind conditions for both spot and line fires. Using tall grass and chaparral, line fires were simulated employing the full fire–atmosphere coupling. Results from two of these experiments show the effects of fire propagation over a small hill. As with previous coupled experiments, the present results show a number of features common to real fires. For example, we show how the well-recognized elliptical fireline shape is a direct result of fire–atmosphere interactions that produce the ‘heading’, ‘flanking’, and ‘backing’ regions of a wind-driven fire with their expected behavior. And, we see how perturbations upon this shape sometimes amplify to become fire whirls along the flanks, which are transported to the head of the fire where they may interact to produce erratic fire behavior.
10
Clark, Terry L., Mary Ann Jenkins, Janice Coen, and David Packham. "A Coupled AtmosphereFire Model: Convective Feedback on Fire-Line Dynamics." Journal of Applied Meteorology 35, no. 6 (June 1996): 875–901. http://dx.doi.org/10.1175/1520-0450(1996)035<0875:acamcf>2.0.co;2.
Full text
11
Coen, Janice L. "Simulation of the Big Elk Fire using coupled atmosphere - fire modeling." International Journal of Wildland Fire 14, no. 1 (2005): 49. http://dx.doi.org/10.1071/wf04047.
Full textAbstract:
Models that simulate wildland fires span a vast range of complexity; the most physically complex present a difficult supercomputing challenge that cannot be solved fast enough to become a forecasting tool. Coupled atmosphere–fire model simulations of the Big Elk Fire, a wildfire that occurred in the Colorado Front Range during 2002, are used to explore whether some factors that make simulations more computationally demanding (such as coupling between the fire and the atmosphere and fine atmospheric model resolution) are needed to capture wildland fire parameters of interest such as fire perimeter growth. In addition to a Control simulation, other simulations remove the feedback to the atmospheric dynamics and use increasingly coarse atmospheric resolution, including some that can be computed in faster than real time on a single processor. These simulations show that, although the feedback between the fire and atmosphere must be included to capture accurately the shape of the fire, the simulations with relatively coarse atmospheric resolution (grid spacing 100–500 m) can qualitatively capture fire growth and behavior such as surface and crown fire spread and smoke transport. A comparison of the computational performance of the model configured at these different spatial resolutions shows that these can be performed faster than real time on a single computer processor. Thus, although this model still requires rigorous testing over a wide range of fire incidents, it is computationally possible to use models that can capture more complex fire behavior (such as rapid changes in intensity, large fire whirls, and interactions between fire, weather, and topography) than those used currently in the field and meet a faster-than-real-time operational constraint.
12
Казаков, Алексей Васильевич, Дмитрий Викторович Бухтояров, Николай Васильевич Смирнов, and Владимир Александрович Григорьев. "AUTOMATIC FIRE PREVENTION SYSTEMS WITH HYPOXIC ATMOSPHERE." Pozharnaia bezopasnost`, no. 2(107) (June 19, 2022): 72–79. http://dx.doi.org/10.37657/vniipo.pb.2022.107.2.007.
Full textAbstract:
Автоматические системы предотвращения пожара создают в помещении искусственную гипоксическую атмосферу, концентрация кислорода в которой исключает воспламенение и дальнейшее развитие пламенного горения по пожарной нагрузке. Показана область применения системы и ее достоинства по сравнению с автоматическими установками пожаротушения. Отмечены основные факторы, которые ограничивают применение систем. Представлены сведения о методиках определения порога воспламенения горючих материалов, а также правила вычисления нормативной концентрации кислорода, которые необходимы для проектирования системы. Сообщается о некоторых зарубежных нормах, а также о разработке национального свода правил для проектирования систем. Приведен ряд условий для безопасного посещения помещений и выполнения работы в гипоксической атмосфере. Automatic fire prevention systems create an artificial hypoxic atmosphere in the room where the oxygen concentration excludes ignition and further development of flame combustion on fire load. There is demonstrated the field of the system application and its advantages in comparison with automatic fire extinguishing systems. The main factors that limit the systems application are gas leaks from the room through leaky building structures and doors. Some types of room heating systems can also cause gas leaks. The tightness of the room can be determined by the fan method. Leaky rooms can also be protected but economic costs and electricity consumption at the same time unreasonably sharply increase. The flammability limit is the main parameter that determines the nitrogen amount to protect the room. There is presented the information about the test method for determining the flammability limit of combustible materials, as well as some experimental data. Three foreign standards define the requirements for the systems design. The national standard for system design is being developed in our country nowadays. Some provisions of this national standard for fire prevention systems are discussed in this article. At the same time, much attention is paid to the people safety staying in an artificial hypoxic atmosphere.
13
Blomqvist, Per, Bror Persson, and Margaret Simonson. "Fire Emissions of Organics into the Atmosphere." Fire Technology 43, no. 3 (July 31, 2007): 213–31. http://dx.doi.org/10.1007/s10694-007-0011-y.
Full text
14
Peace, Mika, Joseph Charney, and John Bally. "Lessons Learned from Coupled Fire-Atmosphere Research and Implications for Operational Fire Prediction and Meteorological Products Provided by the Bureau of Meteorology to Australian Fire Agencies." Atmosphere 11, no. 12 (December 21, 2020): 1380. http://dx.doi.org/10.3390/atmos11121380.
Full textAbstract:
Coupled fire-atmosphere models are simulators that integrate a fire component and an atmospheric component, with the objective of capturing interactions between the fire and atmosphere. As a fire releases energy in the combustion process, the surrounding atmosphere adjusts in response to the energy fluxes; coupled fire-atmosphere (CFA) models aim to resolve the processes through which these adjustments occur. Several CFA models have been developed internationally, mostly by meteorological institutions and primarily for use as a research tool. Research studies have provided valuable insights into some of the atmospheric processes surrounding a fire. The potential to run CFA models in real time is currently limited due to the intensive computational requirements. In addition, there is a need for systematic verification to establish their accuracy and the appropriate circumstances for their use. The Bureau of Meteorology (the Bureau) is responsible for providing relevant and accurate meteorological information to Australian fire agencies to inform decisions for the protection of life and property and to support hazard management activities. The inclusion of temporally and spatially detailed meteorological fields that adjust in response to the energy released by a fire is seen as a component in developing fire prediction systems that capture some of the most impactful fire and weather behavior. The Bureau’s ten-year research and development plan includes a commitment to developing CFA models, with the objective of providing enhanced services to Australian fire agencies. This paper discusses the operational use of fire predictions and simulators, learnings from CFA models and potential future directions for the Bureau in using CFA models to support fire prediction activities.
15
Kiefer, Michael T., Warren E. Heilman, Shiyuan Zhong, Joseph J. Charney, and Xindi Bian. "A study of the influence of forest gaps on fire–atmosphere interactions." Atmospheric Chemistry and Physics 16, no. 13 (July 12, 2016): 8499–509. http://dx.doi.org/10.5194/acp-16-8499-2016.
Full textAbstract:
Abstract. Much uncertainty exists regarding the possible role that gaps in forest canopies play in modulating fire–atmosphere interactions in otherwise horizontally homogeneous forests. This study examines the influence of gaps in forest canopies on atmospheric perturbations induced by a low-intensity fire using the ARPS-CANOPY model, a version of the Advanced Regional Prediction System (ARPS) model with a canopy parameterization. A series of numerical experiments are conducted with a stationary low-intensity fire, represented in the model as a line of enhanced surface sensible heat flux. Experiments are conducted with and without forest gaps, and with gaps in different positions relative to the fire line. For each of the four cases considered, an additional simulation is performed without the fire to facilitate comparison of the fire-perturbed atmosphere and the background state. Analyses of both mean and instantaneous wind velocity, turbulent kinetic energy, air temperature, and turbulent mixing of heat are presented in order to examine the fire-perturbed atmosphere on multiple timescales. Results of the analyses indicate that the impact of the fire on the atmosphere is greatest in the case with the gap centered on the fire and weakest in the case with the gap upstream of the fire. It is shown that gaps in forest canopies have the potential to play a role in the vertical as well as horizontal transport of heat away from the fire. Results also suggest that, in order to understand how the fire will alter wind and turbulence in a heterogeneous forest, one needs to first understand how the forest heterogeneity itself influences the wind and turbulence fields without the fire.
16
Simpson, Colin C., Jason J. Sharples, Jason P. Evans, and Matthew F. McCabe. "Large eddy simulation of atypical wildland fire spread on leeward slopes." International Journal of Wildland Fire 22, no. 5 (2013): 599. http://dx.doi.org/10.1071/wf12072.
Full textAbstract:
The WRF-Fire coupled atmosphere–fire modelling system was used to investigate atypical wildland fire spread on steep leeward slopes through a series of idealised numerical simulations. The simulations are used to investigate both the leeward flow characteristics, such as flow separation, and the fire spread from an ignition region at the base of the leeward slope. The fire spread was considered under varying fuel type and with atmosphere-fire coupling both enabled and disabled. When atmosphere–fire coupling is enabled and there is a high fuel mass density, the fire spread closely resembles that expected during fire channelling. Specifically, the fire spread is initially dominated by upslope spread to the mountain ridge line at an average rate of 2.0kmh–1, followed by predominantly lateral spread close to the ridge line at a maximum rate of 3.6kmh–1. The intermittent rapid lateral spread occurs when updraft–downdraft interfaces, which are associated with strongly circulating horizontal winds at the mid-flame height, move across the fire perimeter close to the ridge line. The updraft–downdraft interfaces are formed due to an interaction between the strong pyro-convection and the terrain-modified winds. Through these results, a new physical explanation of fire channelling is proposed.
17
Teixeira, João C., Gerd A. Folberth, Fiona M. O'Connor, Nadine Unger, and Apostolos Voulgarakis. "Coupling interactive fire with atmospheric composition and climate in the UK Earth System Model." Geoscientific Model Development 14, no. 10 (October 28, 2021): 6515–39. http://dx.doi.org/10.5194/gmd-14-6515-2021.
Full textAbstract:
Abstract. Fire constitutes a key process in the Earth system (ES), being driven by climate as well as affecting the climate by changing atmospheric composition and impacting the terrestrial carbon cycle. However, studies on the effects of fires on atmospheric composition, radiative forcing and climate have been limited to date, as the current generation of ES models (ESMs) does not include fully atmosphere–composition–vegetation coupled fires feedbacks. The aim of this work is to develop and evaluate a fully coupled fire–composition–climate ES model. For this, the INteractive Fires and Emissions algoRithm for Natural envirOnments (INFERNO) fire model is coupled to the atmosphere-only configuration of the UK's Earth System Model (UKESM1). This fire–atmosphere interaction through atmospheric chemistry and aerosols allows for fire emissions to influence radiation, clouds and generally weather, which can consequently influence the meteorological drivers of fire. Additionally, INFERNO is updated based on recent developments in the literature to improve the representation of human and/or economic factors in the anthropogenic ignition and suppression of fire. This work presents an assessment of the effects of interactive fire coupling on atmospheric composition and climate compared to the standard UKESM1 configuration that uses prescribed fire emissions. Results show a similar performance when using the fire–atmosphere coupling (the “online” version of the model) when compared to the offline UKESM1 that uses prescribed fire. The model can reproduce observed present-day global fire emissions of carbon monoxide (CO) and aerosols, despite underestimating the global average burnt area. However, at a regional scale, there is an overestimation of fire emissions over Africa due to the misrepresentation of the underlying vegetation types and an underestimation over equatorial Asia due to a lack of representation of peat fires. Despite this, comparing model results with observations of CO column mixing ratio and aerosol optical depth (AOD) show that the fire–atmosphere coupled configuration has a similar performance when compared to UKESM1. In fact, including the interactive biomass burning emissions improves the interannual CO atmospheric column variability and consequently its seasonality over the main biomass burning regions – Africa and South America. Similarly, for aerosols, the AOD results broadly agree with the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Aerosol Robotic Network (AERONET) observations.
18
Potter, Brian E. "A dynamics based view of atmosphere - fire interactions." International Journal of Wildland Fire 11, no. 4 (2002): 247. http://dx.doi.org/10.1071/wf02008.
Full textAbstract:
Current research on severe fire interactions with the atmosphere focuses largely on examination of correlations between fire growth and various atmospheric properties, and on the development of indices based on these correlations. The author proposes that progress requires understanding the physics and atmospheric dynamics behind the correlations. A conceptual 3-stage model of fire development, based on atmospheric structure, is presented. Using parcel theory and basic atmospheric dynamics equations, the author proposes possible causal explanations for some of the known correlations. The atmospheric dynamics are discussed in terms of the 3-stage model, but can also be viewed more generally. The overall goal is to reframe fire–atmosphere interactions in a way that will allow better understanding and progress in fire science, prediction, and safety.
19
Badlan, Rachel L., Jason J. Sharples, Jason P. Evans, and Rick H. D. McRae. "Factors influencing the development of violent pyroconvection. Part I: fire size and stability." International Journal of Wildland Fire 30, no. 7 (2021): 484. http://dx.doi.org/10.1071/wf20040.
Full textAbstract:
Violent fire-driven convection can manifest as towering pyrocumulus (pyroCu) or pyrocumulonimbus (pyroCb) clouds, which can have devastating impacts on the environment and society. Their associated fire spread is erratic, unpredictable and not generally suppressible. Research into large pyroconvective events has mainly focused on the atmospheric processes involved in normal atmospheric convection, or on surface fire weather and associated fuel conditions. There has been comparatively less attention paid to the role of the fire itself in these coupled fire–atmosphere events. This paper draws on recent insights into dynamic fire propagation and extreme wildfire development to investigate how the fire influences the occurrence of violent pyroconvective events. A static heat source of variable dimension and intensity is used. This is accompanied by a companion paper that extends the analysis by including the effect of fire geometry on the pyroconvective plume. The analyses indicate that the spatial expanse and intensity of large fires are critical factors driving the development of pyroconvective plumes and can override the influence of the stability of the atmosphere. These findings provide motivation for further investigation into the effect of the fire’s attributes on the immediate atmosphere and have the potential to improve forecasting of blow-up fire events.
20
Clements, Craig B., Adam K. Kochanski, Daisuke Seto, Braniff Davis, Christopher Camacho, Neil P. Lareau, Jonathan Contezac, et al. "The FireFlux II experiment: a model-guided field experiment to improve understanding of fire–atmosphere interactions and fire spread." International Journal of Wildland Fire 28, no. 4 (2019): 308. http://dx.doi.org/10.1071/wf18089.
Full textAbstract:
The FireFlux II experiment was conducted in a tall grass prairie located in south-east Texas on 30 January 2013 under a regional burn ban and high fire danger conditions. The goal of the experiment was to better understand micrometeorological aspects of fire spread. The experimental design was guided by the use of a coupled fire–atmosphere model that predicted the fire spread in advance. Preliminary results show that after ignition, a surface pressure perturbation formed and strengthened as the fire front and plume developed, causing an increase in wind velocity at the fire front. The fire-induced winds advected hot combustion gases forward and downwind of the fire front that resulted in acceleration of air through the flame front. Overall, the experiment collected a large set of micrometeorological, air chemistry and fire behaviour data that may provide a comprehensive dataset for evaluating and testing coupled fire–atmosphere model systems.
21
Artés, Tomàs, Marc Castellnou, Tracy Houston Durrant, and Jesús San-Miguel. "Wildfire–atmosphere interaction index for extreme-fire behaviour." Natural Hazards and Earth System Sciences 22, no. 2 (February 16, 2022): 509–22. http://dx.doi.org/10.5194/nhess-22-509-2022.
Full textAbstract:
Abstract. During the last 20 years extreme wildfires have challenged firefighting capabilities. Often, the prediction of the extreme behaviour is essential for the safety of citizens and firefighters. Currently, there are several fire danger indices routinely used by firefighting services, but they are not suited to forecast extreme-wildfire behaviour at the global scale. This article proposes a new fire danger index, the extreme-fire behaviour index (EFBI), based on the analysis of the vertical profiles of the atmosphere above wildfires as an addition to the use of traditional fire danger indices. The EFBI evaluates the ease of interaction between wildfires and the atmosphere that could lead to deep moist convection and erratic and extreme wildfires. Results of this research through the analysis of some of the critical fires in the last years show that the EFBI can potentially be used to provide valuable information to identify convection-driven fires and to enhance fire danger rating schemes worldwide.
22
Kulkarni, A. K., and J. J. Hwang. "Vertical wall fire in a stratified ambient atmosphere." Symposium (International) on Combustion 21, no. 1 (January 1988): 45–51. http://dx.doi.org/10.1016/s0082-0784(88)80230-3.
Full text
23
Benscoter, Brian W., and R. Kelman Wieder. "Variability in organic matter lost by combustion in a boreal bog during the 2001 Chisholm fire." Canadian Journal of Forest Research 33, no. 12 (December 1, 2003): 2509–13. http://dx.doi.org/10.1139/x03-162.
Full textAbstract:
Fire directly releases carbon (C) to the atmosphere through combustion of biomass. An estimated 1470 ± 59 km2 of peatland burns annually in boreal, western Canada, releasing 4.7 ± 0.6 Tg C to the atmosphere via direct combustion. We quantified within-site variation in organic matter lost via combustion in a bog peatland in association with the 116 000-ha Chisholm, Alberta, fire in 2001. We hypothesized that for peatlands with considerable small-scale microtopography (bogs and treed fens), hummocks will burn less than hollows. We found that hollows exhibit more combustion than hummocks, releasing nearly twice as much C to the atmosphere. Our results suggest that spatial variability in species composition and site hydrology within a landform and across a landscape could contribute to considerable spatial variation in the amounts of C released via combustion during peatland fire, although the magnitude of this variation may be dependent on fire severity.
24
Sun, Ruiyu, Mary Ann Jenkins, Steven K. Krueger, William Mell, and Joseph J. Charney. "An evaluation of fire-plume properties simulated with the Fire Dynamics Simulator (FDS) and the Clark coupled wildfire model." Canadian Journal of Forest Research 36, no. 11 (November 1, 2006): 2894–908. http://dx.doi.org/10.1139/x06-138.
Full textAbstract:
Before using a fluid dynamics physically based wildfire model to study wildfire, validation is necessary and model results need to be systematically and objectively analyzed and compared to real fires, which requires suitable data sets. Observational data from the Meteotron experiment are used to evaluate the fire-plume properties simulated by two fluid dynamics numerical wildfire models, the Fire Dynamics Simulator (FDS) and the Clark coupled atmosphere–fire model. Comparisons based on classical plume theory between numerical model and experimental Meteotron results show that plume theory, because of its simplifying assumptions, is a fair but restricted rendition of important plume-averaged properties. The study indicates that the FDS, an explicit and computationally demanding model, produces good agreement with the Meteotron results even at a relatively coarse horizontal grid size of 4 m for the FDS, while the coupled atmosphere–fire model, a less explicit and less computationally demanding model, can produce good agreement, but that the agreement is sensitive to surface vertical-grid sizes and the method by which the energy released from the fire is put into the atmosphere.
25
Xue, Haidong, Xiaolin Hu, Nathan Dahl, and Ming Xue. "Post-frontal Combustion Heat Modeling in DEVS-fire for Coupled Atmosphere-fire Simulation." Procedia Computer Science 9 (2012): 302–11. http://dx.doi.org/10.1016/j.procs.2012.04.032.
Full text
26
Mandel, J., J. D. Beezley, and A. K. Kochanski. "Coupled atmosphere-wildland fire modeling with WRF 3.3 and SFIRE 2011." Geoscientific Model Development 4, no. 3 (July 7, 2011): 591–610. http://dx.doi.org/10.5194/gmd-4-591-2011.
Full textAbstract:
Abstract. We describe the physical model, numerical algorithms, and software structure of a model consisting of the Weather Research and Forecasting (WRF) model, coupled with the fire-spread model (SFIRE) module. 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. SFIRE is implemented by the level set method, which allows a submesh representation of the burning region and a flexible implementation of various kinds of ignition. The coupled model is capable of running on a cluster faster than real time even with fine resolution in dekameters. It is available as a part of the Open Wildland Fire Modeling (OpenWFM) environment at http://openwfm.org, which contains also utilities for visualization, diagnostics, and data processing, including an extended version of the WRF Preprocessing System (WPS). The SFIRE code with a subset of the features is distributed with WRF 3.3 as WRF-Fire.
27
Srock, Alan, Joseph Charney, Brian Potter, and Scott Goodrick. "The Hot-Dry-Windy Index: A New Fire Weather Index." Atmosphere 9, no. 7 (July 19, 2018): 279. http://dx.doi.org/10.3390/atmos9070279.
Full textAbstract:
Fire weather indices are commonly used by fire weather forecasters to predict when weather conditions will make a wildland fire difficult to manage. Complex interactions at multiple scales between fire, fuels, topography, and weather make these predictions extremely difficult. We define a new fire weather index called the Hot-Dry-Windy Index (HDW). HDW uses the basic science of how the atmosphere can affect a fire to define the meteorological variables that can be predicted at synoptic-and meso-alpha-scales that govern the potential for the atmosphere to affect a fire. The new index is formulated to account for meteorological conditions both at the Earth’s surface and in a 500-m layer just above the surface. HDW is defined and then compared with the Haines Index (HI) for four historical fires. The Climate Forecast System Reanalysis (CFSR) is used to provide the meteorological data for calculating the indices. Our results indicate that HDW can identify days on which synoptic-and meso-alpha-scale weather processes can contribute to especially dangerous fire behavior. HDW is shown to perform better than the HI for each of the four historical fires. Additionally, since HDW is based on the meteorological variables that govern the potential for the atmosphere to affect a fire, it is possible to speculate on why HDW would be more or less effective based on the conditions that prevail in a given fire case. The HI, in contrast, does not have a physical basis, which makes speculation on why it works or does not work difficult because the mechanisms are not clear.
28
Linn, Rodman R., Judith L. Winterkamp, James H. Furman, Brett Williams, J. Kevin Hiers, Alexandra Jonko, Joseph J. O’Brien, Kara M. Yedinak, and Scott Goodrick. "Modeling Low Intensity Fires: Lessons Learned from 2012 RxCADRE." Atmosphere 12, no. 2 (January 22, 2021): 139. http://dx.doi.org/10.3390/atmos12020139.
Full textAbstract:
Coupled fire-atmosphere models are increasingly being used to study low-intensity fires, such as those that are used in prescribed fire applications. Thus, the need arises to evaluate these models for their ability to accurately represent fire spread in marginal burning conditions. In this study, wind and fuel data collected during the Prescribed Fire Combustion and Atmospheric Dynamics Research Experiments (RxCADRE) fire campaign were used to generate initial and boundary conditions for coupled fire-atmosphere simulations. We present a novel method to obtain fuels representation at the model grid scale using a combination of imagery, machine learning, and field sampling. Several methods to generate wind input conditions for the model from eight different anemometer measurements are explored. We find a strong sensitivity of fire outcomes to wind inputs. This result highlights the critical need to include variable wind fields as inputs in modeling marginal fire conditions. This work highlights the complexities of comparing physics-based model results against observations, which are more acute in marginal burning conditions, where stronger sensitivities to local variability in wind and fuels drive fire outcomes.
29
Duan, Yulong, Shuo Wang, Wenhe Wang, and Kai Zheng. "Atmospheric disturbance on the gas explosion in closed fire zone." International Journal of Coal Science & Technology 7, no. 4 (February 5, 2020): 752–65. http://dx.doi.org/10.1007/s40789-020-00295-3.
Full textAbstract:
AbstractIn order to avoid serious safety accidents caused by closed fire zone, based on the continuous monitoring of atmospheric pressure at different monitoring points in multiple mines, the atmospheric pressure fluctuation model and the air leakage model were established and analyzed. The change law with time of oxygen concentration and gas concentration in the fire zone were obtained due to atmospheric disturbances under the influence of different pressure difference, volume and size of fire area, wind resistance, gas emission, sealing moments, etc. so as to evaluate the explosion risk of a closed fire zone. Research showed that the mine atmosphere fluctuates with the atmosphere of ground, and the pressure difference between the inner and outer sides of the enclosed fire zone is affected by the periodic fluctuation of atmosphere, which has about 16-h cosine fluctuation and approximate 8-h fixed value. Compared with the fire zone with poor sealing quality, good sealing fire zone has better resistance to atmospheric disturbance. The reduction of oxygen concentration in the inner side of a well-sealed fire zone mainly depends on the dilution of methane, which is more likely to accumulate and rise rapidly. And the fire zone with poor sealing quality is easy to be interfered. The inner oxygen concentration and gas concentration are easily affected by the absolute gas emission and the air leakage in the fire zone. Fire zone with small wind resistance and small volume is especially obvious. At the initial stage of the closed fire zone it's very possible to happen explosion. The time duration of explosion danger varies under different conditions, and the atmospheric disturbance may lead to repeated explosions in some cases. It's suggested to take some methods to avoid explosions according to the real-time situation, closure time, oxygen concentration and gas concentration of fire zone.
30
Achtemeier, Gary L. "Field validation of a free-agent cellular automata model of fire spread with fire - atmosphere coupling." International Journal of Wildland Fire 22, no. 2 (2013): 148. http://dx.doi.org/10.1071/wf11055.
Full textAbstract:
A cellular automata fire model represents ‘elements’ of fire by autonomous agents. A few simple algebraic expressions substituted for complex physical and meteorological processes and solved iteratively yield simulations for ‘super-diffusive’ fire spread and coupled surface-layer (2-m) fire–atmosphere processes. Pressure anomalies, which are integrals of the thermal properties of the overlying heated plume, drive the surface winds around and through the fire. Five simulations with differing fuel and wind conditions were compared with fire and meteorological data from an experimental grassfire (FireFlux). The fire model accurately simulated bulk patterns of measured time-series of 2-m winds at two towers and observed fire behaviour (spread rate, flaming depth and heat released). Fidelity to spatial windfields in the vicinity of the fire was similar to results from full-physics fire models for other grassfires. Accurate predictions of fire spread depend critically on accurate wind speeds and directions at the location of the fire. Simulated fire–atmosphere coupling using FireFlux data increased wind speeds across the fire line by up to a factor of three. With its computational speed relative to full-physics models, the fire model can inform full-physics modellers regarding problems of interest. Although the fire model is tested for homogeneous fuels on flat terrain, the model is designed for simulating complex distributions of fire within heterogeneous distributions of fuels over complex landscapes.
31
Sun, Ruiyu, Steven K. Krueger, Mary Ann Jenkins, Michael A. Zulauf, and Joseph J. Charney. "The importance of fire - atmosphere coupling and boundary-layer turbulence to wildfire spread." International Journal of Wildland Fire 18, no. 1 (2009): 50. http://dx.doi.org/10.1071/wf07072.
Full textAbstract:
The major source of uncertainty in wildfire behavior prediction is the transient behavior of wildfire due to changes in flow in the fire’s environment. The changes in flow are dominated by two factors. The first is the interaction or ‘coupling’ between the fire and the fire-induced flow. The second is the interaction or ‘coupling’ between the fire and the ambient flow driven by turbulence due to wind gustiness and eddies in the atmospheric boundary layer (ABL). In the present study, coupled wildfire–atmosphere large-eddy simulations of grassland fires are used to examine the differences in the rate of spread and area burnt by grass fires in two types of ABL, a buoyancy-dominated ABL and a roll-dominated ABL. The simulations show how a buoyancy-dominated ABL affects fire spread, how a roll-dominated ABL affects fire spread, and how fire lines interact with these two different ABL flow types. The simulations also show how important are fire–atmosphere couplings or fire-induced circulations to fire line spread compared with the direct impact of the turbulence in the two different ABLs. The results have implications for operational wildfire behavior prediction. Ultimately, it will be important to use techniques that include an estimate of uncertainty in wildfire behavior forecasts.
32
Jenkins, Mary Ann. "An examination of the sensitivity of numerically simulated wildfires to low-level atmospheric stability and moisture, and the consequences for the Haines Index." International Journal of Wildland Fire 11, no. 4 (2002): 213. http://dx.doi.org/10.1071/wf02006.
Full textAbstract:
The Haines Index, an operational fire–weather index introduced in 1988 and based on the observed stability and moisture content of the near-surface atmosphere, has been a useful indicator of the potential for high-risk fires in low wind conditions and flat terrain. The Haines Index is of limited use, however, as a predictor of actual fire behavior. To develop a fire–weather index to predict severe or erratic wildfire behavior, an understanding of how the ambient lower-level atmospheric stability and moisture affects the growth of a wildfire is needed. This study is a first step in this process. This study investigates, through four comparative numerical simulations with a coupled wildfire–atmosphere model, the sensitivity of wildland fires to atmospheric stability and moisture, and in the process explores the correspondence between atmospheric stability and moisture, wildfire behavior, and the Haines Index. In the first three fire simulations, the model atmosphere was initially set to identical moisture but different instability conditions that correspond to Haines Indexes for low, moderate, and high potential for severe fire development. In the fourth fire simulation, the initial atmospheric and moisture conditions were for a high-risk fire Haines Index rating, but different from the initial conditions of dryness and stability of the previous experiments. The study indicates that high-risk fire development is sensitive to near-surface atmospheric stability and moisture, and that there is a range of atmospheric stability and moisture conditions that is important to the development of severe or erratic fire behavior, and that this range is within the atmospheric stability and moisture conditions represented by a Haines Index for high potential for severe fire. The analyses also suggest that there is a substantial latitude of fire behavior for fires rated as this Index, indicating that this Index should be further divided, or refined.
33
Park, Yun Hee, and Irina N. Sokolik. "Toward Developing a Climatology of Fire Emissions in Central Asia." Air, Soil and Water Research 9 (January 2016): ASWR.S39940. http://dx.doi.org/10.4137/aswr.s39940.
Full textAbstract:
Fire emissions are a significant mechanism in the carbon cycling from the Earth's surface to the atmosphere, and fire behavior is considerably interacted with weather and climate. However, due to interannual variation of the emissions and nonlinear smoke plume dynamics, understanding the interactions between fire behavior and the atmosphere is challenging. This study aims to establish a climatology of the fire emission in Central Asia and has estimated a feedback of fire emissions to meteorological variables on a seasonal basis using the Weather Research and Forecasting model coupled with Chemistry. The months of April, May, and September have a relatively large number of pixels, where the plume height is located within the boundary layer, and the domain during these months tends to have unstable conditions at the strongest smoke, showing a lower percentage of stable conditions. From the seasonal analysis, the high fire intensity occurs in the summer as smoke travels above the boundary layer, changing temperature profile and increasing the water vapor mixing ratio.
34
Ghaderi, Mohsen, Maryam Ghodrat, and Jason J. Sharples. "LES Simulation of Wind-Driven Wildfire Interaction with Idealized Structures in the Wildland-Urban Interface." Atmosphere 12, no. 1 (December 25, 2020): 21. http://dx.doi.org/10.3390/atmos12010021.
Full textAbstract:
This paper presents a numerical investigation of the impact of a wind-driven surface fire, comparable to a large wildfire, on an obstacle located downstream of the fire source. The numerical modelling was conducted using FireFOAM, a coupled fire-atmosphere model underpinned by a large eddy simulation (LES) solver, which is based on the Eddy Dissipation Concept (EDC) combustion model and implemented in the OpenFOAM platform (an open source CFD tool). The numerical data were validated using the aerodynamic measurements of a full-scale building model in the absence of fire effects. The results highlighted the physical phenomena contributing to the fire spread pattern and its thermal impact on the building. In addition, frequency analysis of the surface temperature fluctuations ahead of the fire front showed that the presence of a building influences the growth and formation of buoyant instabilities, which directly affect the behaviour of the fire’s plume. The coupled fire-atmosphere modelling presented here constitutes a fundamental step towards better understanding the behaviour and potential impacts of large wind-driven wildland fires in wildland-urban interface (WUI) areas.
35
Wang, Chang Jian. "Simulation of Heptane Jet Fire at Low Atmosphere Pressure." Advanced Materials Research 516-517 (May 2012): 1070–73. http://dx.doi.org/10.4028/www.scientific.net/amr.516-517.1070.
Full textAbstract:
Due to safety consideration of storage and transportation of liquid fuel at low atmospheric pressure region, the influence of low atmospheric pressure on heptane jet fire was numerically investigated, based on LES and mixture-fraction combustion model. Injection heptane diameters satisfy Rosin-Rammler distribution. The simulation shows that, low atmospheric pressure has an evident effect on jet fire. It extends the fire length and shortens the lift-off height. The centerline temperature rises to the maximum value more rapidly and then it decays more slowly. The maximum centerline temperature is not sensitive to various atmospheric pressure.
36
Kartsios, Stergios, Theodore Karacostas, Ioannis Pytharoulis, and Alexandros P. Dimitrakopoulos. "Numerical investigation of atmosphere-fire interactions during high-impact wildland fire events in Greece." Atmospheric Research 247 (January 2021): 105253. http://dx.doi.org/10.1016/j.atmosres.2020.105253.
Full text
37
Thomas, C. M., J. J. Sharples, and J. P. Evans. "Modelling the dynamic behaviour of junction fires with a coupled atmosphere–fire model." International Journal of Wildland Fire 26, no. 4 (2017): 331. http://dx.doi.org/10.1071/wf16079.
Full textAbstract:
Dynamic fire behaviour involves rapid changes in fire behaviour without significant changes in ambient conditions, and can compromise firefighter and community safety. Dynamic fire behaviour cannot be captured using spatial implementations of empirical fire-spread models predicated on the assumption of an equilibrium, or quasi-steady, rate of spread. In this study, a coupled atmosphere–fire model is used to model the dynamic propagation of junction fires, i.e. when two firelines merge at an oblique angle. This involves very rapid initial rates of spread, even with no ambient wind. The simulations are in good qualitative agreement with a previous experimental study, and indicate that pyro-convective interaction between the fire and the atmosphere is the key mechanism driving the dynamic fire propagation. An examination of the vertical vorticity in the simulations, and its relationship to the fireline geometry, gives insight into this mechanism. Junction fires have been modelled previously using curvature-dependent rates of spread. In this study, however, although fireline geometry clearly influences rate of spread, no relationship is found between local fireline curvature and the simulated instantaneous local rate of spread. It is possible that such a relationship may be found at larger scales.
38
Loboda, Egor, Denis Kasymov, Mikhail Agafontsev, Vladimir Reyno, Anastasiya Lutsenko, Asya Staroseltseva, Vladislav Perminov, Pavel Martynov, Yuliya Loboda, and Konstantin Orlov. "Crown Fire Modeling and Its Effect on Atmospheric Characteristics." Atmosphere 13, no. 12 (November 27, 2022): 1982. http://dx.doi.org/10.3390/atmos13121982.
Full textAbstract:
The article is concerned with the experimental study of the crown fire effect on atmospheric transport processes: the formation of induced turbulence in the vicinity of the fire source and the transport of aerosol combustion products in the atmosphere surface layer at low altitudes. The studies were carried out in seminatural conditions on the reconstructed forest canopy. It was established that the structural characteristics of fluctuations of some atmosphere physical parameters in the case of a crown fire practically coincide with the obtained earlier values for a steppe fire. The highest concentration of aerosol combustion products was recorded at a height of 10–20 m from the ground surface. It was found that the largest number of aerosol particles formed during a crown fire had a particle diameter of 0.3 to 0.5 µm. As a result of experimental data extrapolation, it is concluded that an excess of aerosol concentration over the background value will be recorded at a distance of up to 2000 m for a given volume of burnt vegetation. It is of interest to further study these factors of the impact of wildfires on atmosphere under the conditions of a real large natural wildfire and determine the limiting distance of aerosol concentration excesses over background values.
39
Kochanski, A. K., M. A. Jenkins, J. Mandel, J. D. Beezley, C. B. Clements, and S. Krueger. "Evaluation of WRF-SFIRE performance with field observations from the FireFlux experiment." Geoscientific Model Development 6, no. 4 (August 2, 2013): 1109–26. http://dx.doi.org/10.5194/gmd-6-1109-2013.
Full textAbstract:
Abstract. This study uses in situ measurements collected during the FireFlux field experiment to evaluate and improve the performance of the coupled atmosphere–fire model WRF-SFIRE. The simulation by WRF-SFIRE of the experimental burn shows that WRF-SFIRE is capable of providing realistic head-fire rate of spread and vertical temperature structure of the fire plume, and fire-induced surface flow and vertical velocities within the plume up to 10 m above ground level. The simulation captured the changes in wind speed and direction before, during, and after fire front passage, along with the arrival times of wind speed, temperature, and updraft maxima, at the two instrumented flux towers used in FireFlux. The model overestimated vertical wind speeds and underestimated horizontal wind speeds measured at tower heights above 10 m. It is hypothesized that the limited model spatial resolution led to overestimates of the fire front depth, heat release rate, and updraft speed. However, on the whole, WRF-SFIRE simulated fire plume behavior that is consistent with FireFlux observations. The study suggests optimal experimental pre-planning, design, and execution strategies for future field campaigns that are intended to evaluate and develop further coupled atmosphere–fire models.
40
Kochanski, A. K., M. A. Jenkins, J. Mandel, J. D. Beezley, C. B. Clements, and S. Krueger. "Evaluation of WRF-SFIRE performance with field observations from the FireFlux experiment." Geoscientific Model Development Discussions 6, no. 1 (January 18, 2013): 121–69. http://dx.doi.org/10.5194/gmdd-6-121-2013.
Full textAbstract:
Abstract. This study uses in-situ measurements collected during the FireFlux field experiment to evaluate and improve the performance of coupled atmosphere-fire model WRF-SFIRE. The simulation of the experimental burn shows that WRF-SFIRE is capable of providing realistic head fire rate-of-spread and the vertical temperature structure of the fire plume, and, up to 10 m above ground level, fire-induced surface flow and vertical velocities within the plume. The model captured the changes in wind speed and direction before, during, and after fire front passage, along with arrival times of wind speed, temperature, and updraft maximae, at the two instrumented flux towers used in FireFlux. The model overestimated vertical velocities and underestimated horizontal wind speeds measured at tower heights above the 10 m, and it is hypothesized that the limited model resolution over estimated the fire front depth, leading to too high a heat release and, subsequently, too strong an updraft. However, on the whole, WRF-SFIRE fire plume behavior is consistent with the interpretation of FireFlux observations. The study suggests optimal experimental pre-planning, design, and execution of future field campaigns that are needed for further coupled atmosphere-fire model development and evaluation.
41
Dixon, Robert K., and Olga N. Krankina. "Forest fires in Russia: carbon dioxide emissions to the atmosphere." Canadian Journal of Forest Research 23, no. 4 (April 1, 1993): 700–705. http://dx.doi.org/10.1139/x93-091.
Full textAbstract:
Boreal forests of Russia play a prominent role in the global carbon cycle and the flux of greenhouse gases to the atmosphere. Large areas of Russian forest burn annually, and contributions to the net flux of carbon to the atmosphere may be significant. Forest fire emissions were calculated for the years 1971–1991 using fire frequency and distribution data and fuel and carbon density for different forest ecoregions of Russia. Both direct carbon release and indirect post-fire biogenic carbon flux were estimated. From 1971 to 1991 the annual total forest area burned by wildfire ranged from 1.41 × 106 to 10.0 × 106 ha. Approximately 15 000–25 000 forest fires occurred annually during this period. Mean annual direct CO2-C emissions from wildfire was approximately 0.05 Pg over this 21-year period. Total post-fire biogenic CO2-C emissions for 1971–1991 ranged from 2.5 to 5.9 Pg (0.12–0.28 Pg annually). Forest fires and other disturbances are expected to be a primary mechanism driving vegetation change associated with projected global climate change. Future forest fire scenarios in Russia based on general circulation model projections suggest that up to 30–50% of the land surface area, or 334 × 106 to 631 × 106 ha of forest, will be affected. An additional 6.7 × 106 to 12.6 × 106 ha of Russian boreal forest are projected to burn annually if general circulation model based vegetation-change scenarios are achieved within the next 50 years. The direct flux of CO2-C from future forest fires is estimated to total 6.1–10.7 Pg over a 50-year period. Indirect post-fire biogenic release of greenhouse gases in the future is expected to be two to six times greater than direct emissions. Forest management and fire-control activities may help reduce wildfire severity and mitigate the associated pulse of greenhouse gases into the atmosphere.
42
Potter, Brian E. "Atmospheric interactions with wildland fire behaviour - II. Plume and vortex dynamics." International Journal of Wildland Fire 21, no. 7 (2012): 802. http://dx.doi.org/10.1071/wf11129.
Full textAbstract:
This paper is the second of two reviewing scientific literature from 100 years of research addressing interactions between the atmosphere and fire behaviour. These papers consider research on the interactions between the fuels burning at any instant and the atmosphere, and the interactions between the atmosphere and those fuels that will eventually burn in a given fire. The first paper reviews the progression from the surface atmospheric properties of temperature, humidity and wind to horizontal and vertical synoptic structures and ends with vertical atmospheric profiles. This second paper addresses plume dynamics and vortices. The review presents several questions and concludes with suggestions for areas of future research.
43
Coen, Janice L., and Philip J. Riggan. "Simulation and thermal imaging of the 2006 Esperanza Wildfire in southern California: application of a coupled weather–wildland fire model." International Journal of Wildland Fire 23, no. 6 (2014): 755. http://dx.doi.org/10.1071/wf12194.
Full textAbstract:
The 2006 Esperanza Fire in Riverside County, California, was simulated with the Coupled Atmosphere–Wildland Fire Environment (CAWFE) model to examine how dynamic interactions of the atmosphere with large-scale fire spread and energy release may affect observed patterns of fire behaviour as mapped using the FireMapper thermal-imaging radiometer. CAWFE simulated the meteorological flow in and near the fire, the fire’s growth as influenced by gusty Santa Ana winds and interactions between the fire and weather through fire-induced winds during the first day of burning. The airflow was characterised by thermally stratified, two-layer flow channelled between the San Bernardino and San Jacinto mountain ranges with transient flow accelerations driving the fire in Cabazon Peak’s lee. The simulation reproduced distinguishing features of the fire including its overall direction and width, rapid spread west-south-westward across canyons, spread up canyons crossing its southern flank, splitting into two heading regions and feathering of the fire line. The simulation correctly depicted the fire’s location at the time of an early-morning incident involving firefighter fatalities. It also depicted periods of deep plume growth, but anomalously described downhill spread of the head of the fire under weak winds that was less rapid than observed. Although capturing the meteorological flow was essential to reproducing the fire’s evolution, fuel factors including fuel load appeared to play a secondary role.
44
Mallia, Derek V., Adam K. Kochanski, Shawn P. Urbanski, Jan Mandel, Angel Farguell, and Steven K. Krueger. "Incorporating a Canopy Parameterization within a Coupled Fire-Atmosphere Model to Improve a Smoke Simulation for a Prescribed Burn." Atmosphere 11, no. 8 (August 7, 2020): 832. http://dx.doi.org/10.3390/atmos11080832.
Full textAbstract:
Forecasting fire growth, plume rise and smoke impacts on air quality remains a challenging task. Wildland fires dynamically interact with the atmosphere, which can impact fire behavior, plume rises, and smoke dispersion. For understory fires, the fire propagation is driven by winds attenuated by the forest canopy. However, most numerical weather prediction models providing meteorological forcing for fire models are unable to resolve canopy winds. In this study, an improved canopy model parameterization was implemented within a coupled fire-atmosphere model (WRF-SFIRE) to simulate a prescribed burn within a forested plot. Simulations with and without a canopy wind model were generated to determine the sensitivity of fire growth, plume rise, and smoke dispersion to canopy effects on near-surface wind flow. Results presented here found strong linkages between the simulated fire rate of spread, heat release and smoke plume evolution. The standard WRF-SFIRE configuration, which uses a logarithmic interpolation to estimate sub-canopy winds, overestimated wind speeds (by a factor 2), fire growth rates and plume rise heights. WRF-SFIRE simulations that implemented a canopy model based on a non-dimensional wind profile, saw significant improvements in sub-canopy winds, fire growth rates and smoke dispersion when evaluated with observations.
45
Mell, William, Mary Ann Jenkins, Jim Gould, and Phil Cheney. "A physics-based approach to modelling grassland fires." International Journal of Wildland Fire 16, no. 1 (2007): 1. http://dx.doi.org/10.1071/wf06002.
Full textAbstract:
Physics-based coupled fire–atmosphere models are based on approximations to the governing equations of fluid dynamics, combustion, and the thermal degradation of solid fuel. They require significantly more computational resources than the most commonly used fire spread models, which are semi-empirical or empirical. However, there are a number of fire behaviour problems, of increasing relevance, that are outside the scope of empirical and semi-empirical models. Examples are wildland–urban interface fires, assessing how well fuel treatments work to reduce the intensity of wildland fires, and investigating the mechanisms and conditions underlying blow-up fires and fire spread through heterogeneous fuels. These problems are not amenable to repeatable full-scale field studies. Suitably validated coupled atmosphere–fire models are one way to address these problems. This paper describes the development of a three-dimensional, fully transient, physics-based computer simulation approach for modelling fire spread through surface fuels. Grassland fires were simulated and compared to findings from Australian experiments. Predictions of the head fire spread rate for a range of ambient wind speeds and ignition line-fire lengths compared favourably to experiments. In addition, two specific experimental cases were simulated in order to evaluate how well the model predicts the development of the entire fire perimeter.
46
Potter, Brian E. "Atmospheric interactions with wildland fire behaviour - I. Basic surface interactions, vertical profiles and synoptic structures." International Journal of Wildland Fire 21, no. 7 (2012): 779. http://dx.doi.org/10.1071/wf11128.
Full textAbstract:
This paper is the first of two reviewing scientific literature from 100 years of research addressing interactions between the atmosphere and fire behaviour. These papers consider research on the interactions between the fuels burning at any instant and the atmosphere, and the interactions between the atmosphere and those fuels that will eventually burn in a given fire. This first paper reviews the progression from the surface atmospheric properties of temperature, humidity and wind to horizontal and vertical synoptic structures and ends with vertical atmospheric profiles. (The companion paper addresses plume dynamics and vortices.) The review reveals several unanswered questions, as well as findings from previous studies that appear forgotten in current research and concludes with suggestions for areas of future research.
47
Clements, Craig B., Neil P. Lareau, Daisuke Seto, Jonathan Contezac, Braniff Davis, Casey Teske, Thomas J. Zajkowski, et al. "Fire weather conditions and fire–atmosphere interactions observed during low-intensity prescribed fires – RxCADRE 2012." International Journal of Wildland Fire 25, no. 1 (2016): 90. http://dx.doi.org/10.1071/wf14173.
Full text
48
Meskeoule Vondou, Fidel, Claude Valery Ngayihi Abbe, Justin Tégawendé Zaida, Philippe Onguene Mvogo, and Ruben Mouangue. "Experimental Study of the Effect of Confining on the Development of Fire in a Closed Compartment." Journal of Combustion 2021 (February 12, 2021): 1–10. http://dx.doi.org/10.1155/2021/6662830.
Full textAbstract:
Backdraft is a complex phenomenon which occurs during cases of confined fires. It appears by a fast deflagration which occurs after the introduction of oxygen into a compartment filled with hot gases rich in unburned combustible vapor. Practically, this situation could occur at the time of intervention of firemen who break the door or when a window breaks under the action of thermal stresses. Based on a strong experimental campaign, the present paper aimed to make a quantitative investigation of the effect of confining on a totally closed fire. With this focus, fire tests were carried out in a completely closed room of dimensions 1.20 m × 1.20 m × 1.02 m, with five sources of fire of different heat release rates. The same fire sources were also tested in a free atmosphere in order to get reference data. After a statistical study of data, a comparative analysis between both results has been done. Its outcome is that confining has a major impact on the quality of combustion and on the fire duration. More precisely, it has been noticed comparatively to fire tests in free atmosphere that confining increases the fire duration by 14.85 percent while it decreases the heat release rate by 21.72 percent.
49
Zou, Yufei, Yuhang Wang, Yun Qian, Hanqin Tian, Jia Yang, and Ernesto Alvarado. "Using CESM-RESFire to understand climate–fire–ecosystem interactions and the implications for decadal climate variability." Atmospheric Chemistry and Physics 20, no. 2 (January 27, 2020): 995–1020. http://dx.doi.org/10.5194/acp-20-995-2020.
Full textAbstract:
Abstract. Large wildfires exert strong disturbance on regional and global climate systems and ecosystems by perturbing radiative forcing as well as the carbon and water balance between the atmosphere and land surface, while short- and long-term variations in fire weather, terrestrial ecosystems, and human activity modulate fire intensity and reshape fire regimes. The complex climate–fire–ecosystem interactions were not fully integrated in previous climate model studies, and the resulting effects on the projections of future climate change are not well understood. Here we use the fully interactive REgion-Specific ecosystem feedback Fire model (RESFire) that was developed in the Community Earth System Model (CESM) to investigate these interactions and their impacts on climate systems and fire activity. We designed two sets of decadal simulations using CESM-RESFire for present-day (2001–2010) and future (2051–2060) scenarios, respectively, and conducted a series of sensitivity experiments to assess the effects of individual feedback pathways among climate, fire, and ecosystems. Our implementation of RESFire, which includes online land–atmosphere coupling of fire emissions and fire-induced land cover change (LCC), reproduces the observed aerosol optical depth (AOD) from space-based Moderate Resolution Imaging Spectroradiometer (MODIS) satellite products and ground-based AErosol RObotic NETwork (AERONET) data; it agrees well with carbon budget benchmarks from previous studies. We estimate the global averaged net radiative effect of both fire aerosols and fire-induced LCC at -0.59±0.52 W m−2, which is dominated by fire aerosol–cloud interactions (-0.82±0.19 W m−2), in the present-day scenario under climatological conditions of the 2000s. The fire-related net cooling effect increases by ∼170 % to -1.60±0.27 W m−2 in the 2050s under the conditions of the Representative Concentration Pathway 4.5 (RCP4.5) scenario. Such considerably enhanced radiative effect is attributed to the largely increased global burned area (+19 %) and fire carbon emissions (+100 %) from the 2000s to the 2050s driven by climate change. The net ecosystem exchange (NEE) of carbon between the land and atmosphere components in the simulations increases by 33 % accordingly, implying that biomass burning is an increasing carbon source at short-term timescales in the future. High-latitude regions with prevalent peatlands would be more vulnerable to increased fire threats due to climate change, and the increase in fire aerosols could counter the projected decrease in anthropogenic aerosols due to air pollution control policies in many regions. We also evaluate two distinct feedback mechanisms that are associated with fire aerosols and fire-induced LCC, respectively. On a global scale, the first mechanism imposes positive feedbacks to fire activity through enhanced droughts with suppressed precipitation by fire aerosol–cloud interactions, while the second one manifests as negative feedbacks due to reduced fuel loads by fire consumption and post-fire tree mortality and recovery processes. These two feedback pathways with opposite effects compete at regional to global scales and increase the complexity of climate–fire–ecosystem interactions and their climatic impacts.
50
Badlan, Rachel L., Jason J. Sharples, Jason P. Evans, and Rick H. D. McRae. "Factors influencing the development of violent pyroconvection. Part II: fire geometry and intensity." International Journal of Wildland Fire 30, no. 7 (2021): 498. http://dx.doi.org/10.1071/wf20041.
Full textAbstract:
Fire spread associated with violent pyrogenic convection is highly unpredictable and difficult to suppress. Wildfire-driven convection may generate cumulonimbus (storm) clouds, also known as pyrocumulonimbus (pyroCb). Research into such phenomena has tended to treat the fire on the surface and convection in the atmosphere above as separate processes. We used a numerical model to examine the effect of fire geometry on the height of a pyroconvective plume, using idealised model runs in a neutral atmosphere. The role of geometry was investigated because large areal fires have been associated with the development of pyroCb. Complementary results (detailed in Part I) are extended by considering the effect that fire shape can have on plume height by comparing circular, square, and rectangular fires of varying length and width, representing the difference between firelines and areal fires. Results reveal that the perimeter/area ratio influenced the amount of entrainment that the plume experiences and therefore the height to which the plume rises before it loses buoyancy. These results will aid in the prediction of blow-up fires (whereby a fire exhibits a rapid increase in rate of spread or rate of spread) and may therefore be useful in determining where fire agencies deploy their limited resources.