Science.gov

Sample records for computational fire modeling

  1. Computational fire modeling for aircraft fire research

    SciTech Connect

    Nicolette, V.F.

    1996-11-01

    This report summarizes work performed by Sandia National Laboratories for the Federal Aviation Administration. The technical issues involved in fire modeling for aircraft fire research are identified, as well as computational fire tools for addressing those issues, and the research which is needed to advance those tools in order to address long-range needs. Fire field models are briefly reviewed, and the VULCAN model is selected for further evaluation. Calculations are performed with VULCAN to demonstrate its applicability to aircraft fire problems, and also to gain insight into the complex problem of fires involving aircraft. Simulations are conducted to investigate the influence of fire on an aircraft in a cross-wind. The interaction of the fuselage, wind, fire, and ground plane is investigated. Calculations are also performed utilizing a large eddy simulation (LES) capability to describe the large- scale turbulence instead of the more common k-{epsilon} turbulence model. Additional simulations are performed to investigate the static pressure and velocity distributions around a fuselage in a cross-wind, with and without fire. The results of these simulations provide qualitative insight into the complex interaction of a fuselage, fire, wind, and ground plane. Reasonable quantitative agreement is obtained in the few cases for which data or other modeling results exist Finally, VULCAN is used to quantify the impact of simplifying assumptions inherent in a risk assessment compatible fire model developed for open pool fire environments. The assumptions are seen to be of minor importance for the particular problem analyzed. This work demonstrates the utility of using a fire field model for assessing the limitations of simplified fire models. In conclusion, the application of computational fire modeling tools herein provides both qualitative and quantitative insights into the complex problem of aircraft in fires.

  2. Wild Fire Computer Model Helps Firefighters

    ScienceCinema

    Canfield, Jesse

    2016-07-12

    A high-tech computer model called HIGRAD/FIRETEC, the cornerstone of a collaborative effort between U.S. Forest Service Rocky Mountain Research Station and Los Alamos National Laboratory, provides insights that are essential for front-line fire fighters. The science team is looking into levels of bark beetle-induced conditions that lead to drastic changes in fire behavior and how variable or erratic the behavior is likely to be.

  3. Wild Fire Computer Model Helps Firefighters

    SciTech Connect

    Canfield, Jesse

    2012-09-04

    A high-tech computer model called HIGRAD/FIRETEC, the cornerstone of a collaborative effort between U.S. Forest Service Rocky Mountain Research Station and Los Alamos National Laboratory, provides insights that are essential for front-line fire fighters. The science team is looking into levels of bark beetle-induced conditions that lead to drastic changes in fire behavior and how variable or erratic the behavior is likely to be.

  4. Computational modeling of composite material fires.

    SciTech Connect

    Brown, Alexander L.; Erickson, Kenneth L.; Hubbard, Joshua Allen; Dodd, Amanda B.

    2010-10-01

    Composite materials behave differently from conventional fuel sources and have the potential to smolder and burn for extended time periods. As the amount of composite materials on modern aircraft continues to increase, understanding the response of composites in fire environments becomes increasingly important. An effort is ongoing to enhance the capability to simulate composite material response in fires including the decomposition of the composite and the interaction with a fire. To adequately model composite material in a fire, two physical model development tasks are necessary; first, the decomposition model for the composite material and second, the interaction with a fire. A porous media approach for the decomposition model including a time dependent formulation with the effects of heat, mass, species, and momentum transfer of the porous solid and gas phase is being implemented in an engineering code, ARIA. ARIA is a Sandia National Laboratories multiphysics code including a range of capabilities such as incompressible Navier-Stokes equations, energy transport equations, species transport equations, non-Newtonian fluid rheology, linear elastic solid mechanics, and electro-statics. To simulate the fire, FUEGO, also a Sandia National Laboratories code, is coupled to ARIA. FUEGO represents the turbulent, buoyantly driven incompressible flow, heat transfer, mass transfer, and combustion. FUEGO and ARIA are uniquely able to solve this problem because they were designed using a common architecture (SIERRA) that enhances multiphysics coupling and both codes are capable of massively parallel calculations, enhancing performance. The decomposition reaction model is developed from small scale experimental data including thermogravimetric analysis (TGA) and Differential Scanning Calorimetry (DSC) in both nitrogen and air for a range of heating rates and from available data in the literature. The response of the composite material subject to a radiant heat flux boundary

  5. Modeling fires in adjacent ship compartments with computational fluid dynamics

    SciTech Connect

    Wix, S.D.; Cole, J.K.; Koski, J.A.

    1998-05-10

    This paper presents an analysis of the thermal effects on radioactive (RAM) transportation packages with a fire in an adjacent compartment. An assumption for this analysis is that the adjacent hold fire is some sort of engine room fire. Computational fluid dynamics (CFD) analysis tools were used to perform the analysis in order to include convective heat transfer effects. The analysis results were compared to experimental data gathered in a series of tests on tile US Coast Guard ship Mayo Lykes located at Mobile, Alabama.

  6. Application of computational fluid dynamics modelling in the process of forensic fire investigation: problems and solutions.

    PubMed

    Delémont, O; Martin, J-C

    2007-04-11

    Fire modelling has been gaining more and more interest into the community of forensic fire investigation. Despite an attractiveness that is partially justified, the application of fire models in that field of investigation rises some difficulties. Therefore, the understanding of the basic principles of the two main categories of fire models, the knowledge of their effective potential and their limitations are crucial for a valid and reliable application in forensic science. The present article gives an overview of the principle and basics that characterise the two kinds of fire models: zone models and field models. Whereas the first ones are developed on the basis of mathematical relation from empirical observations, such as stratification of fluid zones, and give a relatively broad view of mass and energy exchanges in an enclosure, the latter are based on fundamentals of fluid mechanics and represent the application of Computational Fluid Dynamics (CFD) to fire scenarii. Consequently, the data that are obtained from these two categories of fire models differ in nature, quality and quantity. First used in a fire safety perspective, fire models are not easily applied to assess parts of forensic fire investigation. A suggestion is proposed for the role of fire modelling in this domain of competence: a new tool for the evaluation of alternative hypotheses of origin and cause by considering the dynamic development of the fire. An example of a real case where such an approach was followed is explained and the evaluation of the obtained results comparing to traces revealed during the on-site investigation is enlightened.

  7. Computer Room Fire Protection.

    ERIC Educational Resources Information Center

    Price, Bennett J.

    1990-01-01

    Notes that economic and service factors may dictate that special fire protection measures be given to computer rooms. The discussion covers emergency planning, various types of fire detection and suppression systems, and future options, with particular attention to halon and possible halon replacements. A list of suggested readings is provided.…

  8. Forest-fire models

    Treesearch

    Haiganoush Preisler; Alan Ager

    2013-01-01

    For applied mathematicians forest fire models refer mainly to a non-linear dynamic system often used to simulate spread of fire. For forest managers forest fire models may pertain to any of the three phases of fire management: prefire planning (fire risk models), fire suppression (fire behavior models), and postfire evaluation (fire effects and economic models). In...

  9. Cinema Fire Modelling by FDS

    NASA Astrophysics Data System (ADS)

    Glasa, J.; Valasek, L.; Weisenpacher, P.; Halada, L.

    2013-02-01

    Recent advances in computer fluid dynamics (CFD) and rapid increase of computational power of current computers have led to the development of CFD models capable to describe fire in complex geometries incorporating a wide variety of physical phenomena related to fire. In this paper, we demonstrate the use of Fire Dynamics Simulator (FDS) for cinema fire modelling. FDS is an advanced CFD system intended for simulation of the fire and smoke spread and prediction of thermal flows, toxic substances concentrations and other relevant parameters of fire. The course of fire in a cinema hall is described focusing on related safety risks. Fire properties of flammable materials used in the simulation were determined by laboratory measurements and validated by fire tests and computer simulations

  10. UTILIZATION OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY FIRE DYNAMICS SIMULATION COMPUTER MODEL

    SciTech Connect

    L. BARTLEIN

    2001-05-01

    The objective of this report is to provide a methodology for utilization of the NIST FDS code to evaluate the effects of radiant and convective heating from single and multiple fire sources, on heat sensitive targets as Special Nuclear Materials (SNM), and High Explosives (HE). The presentation will demonstrate practical applications of the FDS computer program in fire hazards analysis, and illustrate the advantages over hand calculations for radiant heat and convective transfer and fire progression. The ''visualization'' of radiant and convective heat effects will be demonstrated as a tool for supporting conclusions of fire hazards analysis and TSR development.

  11. Development of a numerical computer code and circuit element models for simulation of firing systems

    SciTech Connect

    Carpenter, K.H. . Dept. of Electrical and Computer Engineering)

    1990-07-02

    Numerical simulation of firing systems requires both the appropriate circuit analysis framework and the special element models required by the application. We have modified the SPICE circuit analysis code (version 2G.6), developed originally at the Electronic Research Laboratory of the University of California, Berkeley, to allow it to be used on MSDOS-based, personal computers and to give it two additional circuit elements needed by firing systems--fuses and saturating inductances. An interactive editor and a batch driver have been written to ease the use of the SPICE program by system designers, and the interactive graphical post processor, NUTMEG, supplied by U. C. Berkeley with SPICE version 3B1, has been interfaced to the output from the modified SPICE. Documentation and installation aids have been provided to make the total software system accessible to PC users. Sample problems show that the resulting code is in agreement with the FIRESET code on which the fuse model was based (with some modifications to the dynamics of scaling fuse parameters). In order to allow for more complex simulations of firing systems, studies have been made of additional special circuit elements--switches and ferrite cored inductances. A simple switch model has been investigated which promises to give at least a first approximation to the physical effects of a non ideal switch, and which can be added to the existing SPICE circuits without changing the SPICE code itself. The effect of fast rise time pulses on ferrites has been studied experimentally in order to provide a base for future modeling and incorporation of the dynamic effects of changes in core magnetization into the SPICE code. This report contains detailed accounts of the work on these topics performed during the period it covers, and has appendices listing all source code written documentation produced.

  12. Computing the Local Field Potential (LFP) from Integrate-and-Fire Network Models

    PubMed Central

    Cuntz, Hermann; Lansner, Anders; Panzeri, Stefano; Einevoll, Gaute T.

    2015-01-01

    Leaky integrate-and-fire (LIF) network models are commonly used to study how the spiking dynamics of neural networks changes with stimuli, tasks or dynamic network states. However, neurophysiological studies in vivo often rather measure the mass activity of neuronal microcircuits with the local field potential (LFP). Given that LFPs are generated by spatially separated currents across the neuronal membrane, they cannot be computed directly from quantities defined in models of point-like LIF neurons. Here, we explore the best approximation for predicting the LFP based on standard output from point-neuron LIF networks. To search for this best “LFP proxy”, we compared LFP predictions from candidate proxies based on LIF network output (e.g, firing rates, membrane potentials, synaptic currents) with “ground-truth” LFP obtained when the LIF network synaptic input currents were injected into an analogous three-dimensional (3D) network model of multi-compartmental neurons with realistic morphology, spatial distributions of somata and synapses. We found that a specific fixed linear combination of the LIF synaptic currents provided an accurate LFP proxy, accounting for most of the variance of the LFP time course observed in the 3D network for all recording locations. This proxy performed well over a broad set of conditions, including substantial variations of the neuronal morphologies. Our results provide a simple formula for estimating the time course of the LFP from LIF network simulations in cases where a single pyramidal population dominates the LFP generation, and thereby facilitate quantitative comparison between computational models and experimental LFP recordings in vivo. PMID:26657024

  13. Computing the Local Field Potential (LFP) from Integrate-and-Fire Network Models.

    PubMed

    Mazzoni, Alberto; Lindén, Henrik; Cuntz, Hermann; Lansner, Anders; Panzeri, Stefano; Einevoll, Gaute T

    2015-12-01

    Leaky integrate-and-fire (LIF) network models are commonly used to study how the spiking dynamics of neural networks changes with stimuli, tasks or dynamic network states. However, neurophysiological studies in vivo often rather measure the mass activity of neuronal microcircuits with the local field potential (LFP). Given that LFPs are generated by spatially separated currents across the neuronal membrane, they cannot be computed directly from quantities defined in models of point-like LIF neurons. Here, we explore the best approximation for predicting the LFP based on standard output from point-neuron LIF networks. To search for this best "LFP proxy", we compared LFP predictions from candidate proxies based on LIF network output (e.g, firing rates, membrane potentials, synaptic currents) with "ground-truth" LFP obtained when the LIF network synaptic input currents were injected into an analogous three-dimensional (3D) network model of multi-compartmental neurons with realistic morphology, spatial distributions of somata and synapses. We found that a specific fixed linear combination of the LIF synaptic currents provided an accurate LFP proxy, accounting for most of the variance of the LFP time course observed in the 3D network for all recording locations. This proxy performed well over a broad set of conditions, including substantial variations of the neuronal morphologies. Our results provide a simple formula for estimating the time course of the LFP from LIF network simulations in cases where a single pyramidal population dominates the LFP generation, and thereby facilitate quantitative comparison between computational models and experimental LFP recordings in vivo.

  14. Computer Calculation of Fire Danger

    Treesearch

    William A. Main

    1969-01-01

    This paper describes a computer program that calculates National Fire Danger Rating Indexes. fuel moisture, buildup index, and drying factor are also available. The program is written in FORTRAN and is usable on even the smallest compiler.

  15. Mass Fire Model Concept

    DTIC Science & Technology

    1981-05-31

    ignitions to have approximated mass fire conditions. Observer reports and ex post facto reconstructions of these events establish some qualitative and...fire behavior. A model of urban mass fire behavior, thus, cannot be totally based upon the results of full scale empirical observations . The data are...previous research and observations . From the standpoint of urban mass fires, all detailed tests have been small fires. Leaving aside, for the moment, the

  16. Computer evaluation of existing and proposed fire lookouts

    Treesearch

    Romain M. Mees

    1976-01-01

    A computer simulation model has been developed for evaluating the fire detection capabilities of existing and proposed lookout stations. The model uses coordinate location of fires and lookouts, tower elevation, and topographic data to judge location of stations, and to determine where a fire can be seen. The model was tested by comparing it with manual detection on a...

  17. BPACK -- A computer model package for boiler reburning/co-firing performance evaluations. User`s manual, Volume 1

    SciTech Connect

    Wu, K.T.; Li, B.; Payne, R.

    1992-06-01

    This manual presents and describes a package of computer models uniquely developed for boiler thermal performance and emissions evaluations by the Energy and Environmental Research Corporation. The model package permits boiler heat transfer, fuels combustion, and pollutant emissions predictions related to a number of practical boiler operations such as fuel-switching, fuels co-firing, and reburning NO{sub x} reductions. The models are adaptable to most boiler/combustor designs and can handle burner fuels in solid, liquid, gaseous, and slurried forms. The models are also capable of performing predictions for combustion applications involving gaseous-fuel reburning, and co-firing of solid/gas, liquid/gas, gas/gas, slurry/gas fuels. The model package is conveniently named as BPACK (Boiler Package) and consists of six computer codes, of which three of them are main computational codes and the other three are input codes. The three main codes are: (a) a two-dimensional furnace heat-transfer and combustion code: (b) a detailed chemical-kinetics code; and (c) a boiler convective passage code. This user`s manual presents the computer model package in two volumes. Volume 1 describes in detail a number of topics which are of general users` interest, including the physical and chemical basis of the models, a complete description of the model applicability, options, input/output, and the default inputs. Volume 2 contains a detailed record of the worked examples to assist users in applying the models, and to illustrate the versatility of the codes.

  18. Regulation of firing frequency in a computational model of a midbrain dopaminergic neuron.

    PubMed

    Kuznetsova, Anna Y; Huertas, Marco A; Kuznetsov, Alexey S; Paladini, Carlos A; Canavier, Carmen C

    2010-06-01

    Dopaminergic (DA) neurons of the mammalian midbrain exhibit unusually low firing frequencies in vitro. Furthermore, injection of depolarizing current induces depolarization block before high frequencies are achieved. The maximum steady and transient rates are about 10 and 20 Hz, respectively, despite the ability of these neurons to generate bursts at higher frequencies in vivo. We use a three-compartment model calibrated to reproduce DA neuron responses to several pharmacological manipulations to uncover mechanisms of frequency limitation. The model exhibits a slow oscillatory potential (SOP) dependent on the interplay between the L-type Ca(2+) current and the small conductance K(+) (SK) current that is unmasked by fast Na(+) current block. Contrary to previous theoretical work, the SOP does not pace the steady spiking frequency in our model. The main currents that determine the spontaneous firing frequency are the subthreshold L-type Ca(2+) and the A-type K(+) currents. The model identifies the channel densities for the fast Na(+) and the delayed rectifier K(+) currents as critical parameters limiting the maximal steady frequency evoked by a depolarizing pulse. We hypothesize that the low maximal steady frequencies result from a low safety factor for action potential generation. In the model, the rate of Ca(2+) accumulation in the distal dendrites controls the transient initial frequency in response to a depolarizing pulse. Similar results are obtained when the same model parameters are used in a multi-compartmental model with a realistic reconstructed morphology, indicating that the salient contributions of the dendritic architecture have been captured by the simpler model.

  19. Regulation of Firing Frequency in a Computational Model of a Midbrain Dopaminergic Neuron

    PubMed Central

    Kuznetsova, Anna Y; Huertas, Marco A.; Kuznetsov, Alexey S; Paladini, Carlos A; Canavier, Carmen C

    2010-01-01

    Dopaminergic (DA) neurons of the mammalian midbrain exhibit unusually low firing frequencies in vitro. Furthermore, injection of depolarizing current induces depolarization block before high frequencies are achieved. The maximum steady and transient rates are about 10 and 20 Hz, respectively, despite the ability of these neurons to generate bursts at higher frequencies in vivo. We use a three-compartment model calibrated to reproduce DA neuron responses to several pharmacological manipulations to uncover mechanisms of frequency limitation. The model exhibits a slow oscillatory potential (SOP) dependent on the interplay between the L-type Ca2+ current and the small conductance K+ (SK) current that is unmasked by fast Na+ current block. Contrary to previous theoretical work, the SOP does not pace the steady spiking frequency in our model. The main currents that determine the spontaneous firing frequency are the subthreshold L-type Ca2+ and the A-type K+ currents. The model identifies the channel densities for the fast Na+ and the delayed rectifier K+ currents as critical parameters limiting the maximal steady frequency evoked by a depolarizing pulse. We hypothesize that the low maximal steady frequencies result from a low safety factor for action potential generation. In the model, the rate of Ca2+ accumulation in the distal dendrites controls the transient initial frequency in response to a depolarizing pulse. Similar results are obtained when the same model parameters are used in a multi-compartmental model with a realistic reconstructed morphology, indicating that the salient contributions of the dendritic architecture have been captured by the simpler model. PMID:20217204

  20. Linking 3D spatial models of fuels and fire: Effects of spatial heterogeneity on fire behavior

    Treesearch

    Russell A. Parsons; William E. Mell; Peter McCauley

    2011-01-01

    Crownfire endangers fire fighters and can have severe ecological consequences. Prediction of fire behavior in tree crowns is essential to informed decisions in fire management. Current methods used in fire management do not address variability in crown fuels. New mechanistic physics-based fire models address convective heat transfer with computational fluid dynamics (...

  1. Interfacing materials models with fire field models

    SciTech Connect

    Nicolette, V.F.; Tieszen, S.R.; Moya, J.L.

    1995-12-01

    For flame spread over solid materials, there has traditionally been a large technology gap between fundamental combustion research and the somewhat simplistic approaches used for practical, real-world applications. Recent advances in computational hardware and computational fluid dynamics (CFD)-based software have led to the development of fire field models. These models, when used in conjunction with material burning models, have the potential to bridge the gap between research and application by implementing physics-based engineering models in a transient, multi-dimensional tool. This paper discusses the coupling that is necessary between fire field models and burning material models for the simulation of solid material fires. Fire field models are capable of providing detailed information about the local fire environment. This information serves as an input to the solid material combustion submodel, which subsequently calculates the impact of the fire environment on the material. The response of the solid material (in terms of thermal response, decomposition, charring, and off-gassing) is then fed back into the field model as a source of mass, momentum and energy. The critical parameters which must be passed between the field model and the material burning model have been identified. Many computational issues must be addressed when developing such an interface. Some examples include the ability to track multiple fuels and species, local ignition criteria, and the need to use local grid refinement over the burning material of interest.

  2. FARSITE: Fire Area Simulator-model development and evaluation

    Treesearch

    Mark A. Finney

    1998-01-01

    A computer simulation model, FARSITE, includes existing fire behavior models for surface, crown, spotting, point-source fire acceleration, and fuel moisture. The model's components and assumptions are documented. Simulations were run for simple conditions that illustrate the effect of individual fire behavior models on two-dimensional fire growth.

  3. Fire modeling code comparisons. Final report

    SciTech Connect

    Mowrer, F.W.; Gautier, B.

    1998-09-01

    There is a significant effort taking place in the US nuclear power industry to provide an option for risk-informed/performance-based fire protection programs. One of the requirements for such a program is the ability to deterministically model the characteristics and consequences of a postulated fire in terms of initiation, growth and propagation. There are two general classifications of methods to accomplish this, namely computational fluid dynamics models and the more simplified zone models. For many applications, zone models will provide adequate results. Zone models have been used for probabilistic risk assessments and fire hazard analyses. However, a lack of comparative verification and established confidence in the results has limited their application. This report compares the features and capabilities of four zone type fire models: FIVE, CFAST, COMPBRNIIIe, and MAGIC. The main features of the models are documented in matrix form. The model are benchmarked against three series of existing large-scale fire tests.

  4. Qualitative properties of solutions for the noisy integrate and fire model in computational neuroscience

    NASA Astrophysics Data System (ADS)

    Carrillo, José Antonio; Perthame, Benoît; Salort, Delphine; Smets, Didier

    2015-09-01

    The Noisy Integrate-and-Fire equation is a standard non-linear Fokker-Planck equation used to describe the activity of a homogeneous neural network characterized by its connectivity b (each neuron connected to all others through synaptic weights); b  >  0 describes excitatory networks and b  <  0 inhibitory networks. In the excitatory case, it was proved that, once the proportion of neurons that are close to their action potential {{V}\\text{F}} is too high, solutions cannot exist for all times. In this paper, we show a priori uniform bounds in time on the firing rate to discard the scenario of blow-up, and, for small connectivity, we prove qualitative properties on the long time behavior of solutions. The methods are based on the one hand on relative entropy and Poincaré inequalities leading to L2 estimates and on the other hand, on the notion of ‘universal super-solution’ and parabolic regularizing effects to obtain {{L}∞} bounds.

  5. Managing wildland fires: integrating weather models into fire projections

    Treesearch

    Anne M. Rosenthal; Francis Fujioka

    2004-01-01

    Flames from the Old Fire sweep through lands north of San Bernardino during late fall of 2003. Like many Southern California fires, the Old Fire consumed susceptible forests at the urban-wildland interface and spread to nearby city neighborhoods. By incorporating weather models into fire perimeter projections, scientist Francis Fujioka is improving fire modeling as a...

  6. Modeling the spatial distribution of forest crown biomass and effects on fire behavior with FUEL3D and WFDS

    Treesearch

    Russell A. Parsons; William Mell; Peter McCauley

    2010-01-01

    Crown fire poses challenges to fire managers and can endanger fire fighters. Understanding of how fire interacts with tree crowns is essential to informed decisions about crown fire. Current operational crown fire predictions in the United States assume homogeneous crown fuels. While a new class of research fire models, which model fire behavior with computational...

  7. Fighting Fire with Fire: Modeling the Datacenter-Scale Effects of Targeted Superlattice Thermal Management

    DTIC Science & Technology

    2011-01-01

    Fighting Fire with Fire : Modeling the Datacenter-Scale Effects of Targeted Superlattice Thermal Management Susmit Biswas?, Mohit Tiwari†, Timothy...Sherwood† Luke Theogarajan‡, Frederic T. Chong† Lawrence Livermore National Laboratory, Livermore, CA - 94550, USA? Department of Computer Science , UC...JUN 2011 2. REPORT TYPE 3. DATES COVERED 00-00-2011 to 00-00-2011 4. TITLE AND SUBTITLE Fighting Fire with Fire : Modeling the Datacenter

  8. Experimental Benchmarking of Fire Modeling Simulations. Final Report

    SciTech Connect

    Greiner, Miles; Lopez, Carlos

    2003-10-08

    A series of large-scale fire tests were performed at Sandia National Laboratories to simulate a nuclear waste transport package under severe accident conditions. The test data were used to benchmark and adjust the Container Analysis Fire Environment (CAFE) computer code. CAFE is a computational fluid dynamics fire model that accurately calculates the heat transfer from a large fire to a massive engulfed transport package. CAFE will be used in transport package design studies and risk analyses.

  9. Modelling of fire count data: fire disaster risk in Ghana.

    PubMed

    Boadi, Caleb; Harvey, Simon K; Gyeke-Dako, Agyapomaa

    2015-01-01

    Stochastic dynamics involved in ecological count data require distribution fitting procedures to model and make informed judgments. The study provides empirical research, focused on the provision of an early warning system and a spatial graph that can detect societal fire risks. It offers an opportunity for communities, organizations, risk managers, actuaries and governments to be aware of, and understand fire risks, so that they will increase the direct tackling of the threats posed by fire. Statistical distribution fitting method that best helps identify the stochastic dynamics of fire count data is used. The aim is to provide a fire-prediction model and fire spatial graph for observed fire count data. An empirical probability distribution model is fitted to the fire count data and compared to the theoretical probability distribution of the stochastic process of fire count data. The distribution fitted to the fire frequency count data helps identify the class of models that are exhibited by the fire and provides time leading decisions. The research suggests that fire frequency and loss (fire fatalities) count data in Ghana are best modelled with a Negative Binomial Distribution. The spatial map of observed fire frequency and fatality measured over 5 years (2007-2011) offers in this study a first regional assessment of fire frequency and fire fatality in Ghana.

  10. 2013 Annual Report: Fire Modeling Institute

    Treesearch

    Robin J. Innes; Faith Ann Heinsch; Kristine M. Lee

    2014-01-01

    The Fire Modeling Institute (FMI) of the U.S. Forest Service, Rocky Mountain Research Station (RMRS), is a national and international resource for fire managers. Located within the Fire, Fuel, and Smoke Science Program at the Missoula Fire Sciences Laboratory (Fire Lab) in Montana, FMI helps managers utilize fire and fuel science and technology developed throughout the...

  11. Fire behavior modeling-a decision tool

    Treesearch

    Jack Cohen; Bill Bradshaw

    1986-01-01

    The usefulness of an analytical model as a fire management decision tool is determined by the correspondence of its descriptive capability to the specific decision context. Fire managers must determine the usefulness of fire models as a decision tool when applied to varied situations. Because the wildland fire phenomenon is complex, analytical fire spread models will...

  12. Consequence modeling using the fire dynamics simulator.

    PubMed

    Ryder, Noah L; Sutula, Jason A; Schemel, Christopher F; Hamer, Andrew J; Van Brunt, Vincent

    2004-11-11

    The use of Computational Fluid Dynamics (CFD) and in particular Large Eddy Simulation (LES) codes to model fires provides an efficient tool for the prediction of large-scale effects that include plume characteristics, combustion product dispersion, and heat effects to adjacent objects. This paper illustrates the strengths of the Fire Dynamics Simulator (FDS), an LES code developed by the National Institute of Standards and Technology (NIST), through several small and large-scale validation runs and process safety applications. The paper presents two fire experiments--a small room fire and a large (15 m diameter) pool fire. The model results are compared to experimental data and demonstrate good agreement between the models and data. The validation work is then extended to demonstrate applicability to process safety concerns by detailing a model of a tank farm fire and a model of the ignition of a gaseous fuel in a confined space. In this simulation, a room was filled with propane, given time to disperse, and was then ignited. The model yields accurate results of the dispersion of the gas throughout the space. This information can be used to determine flammability and explosive limits in a space and can be used in subsequent models to determine the pressure and temperature waves that would result from an explosion. The model dispersion results were compared to an experiment performed by Factory Mutual. Using the above examples, this paper will demonstrate that FDS is ideally suited to build realistic models of process geometries in which large scale explosion and fire failure risks can be evaluated with several distinct advantages over more traditional CFD codes. Namely transient solutions to fire and explosion growth can be produced with less sophisticated hardware (lower cost) than needed for traditional CFD codes (PC type computer verses UNIX workstation) and can be solved for longer time histories (on the order of hundreds of seconds of computed time) with

  13. BehavePlus fire modeling system, version 5.0: Design and Features

    Treesearch

    Faith Ann Heinsch; Patricia L. Andrews

    2010-01-01

    The BehavePlus fire modeling system is a computer program that is based on mathematical models that describe wildland fire behavior and effects and the fire environment. It is a flexible system that produces tables, graphs, and simple diagrams. It can be used for a host of fire management applications, including projecting the behavior of an ongoing fire, planning...

  14. BehavePlus fire modeling system, version 4.0: User's Guide

    Treesearch

    Patricia L. Andrews; Collin D. Bevins; Robert C. Seli

    2005-01-01

    The BehavePlus fire modeling system is a program for personal computers that is a collection of mathematical models that describe fire and the fire environment. It is a flexible system that produces tables, graphs, and simple diagrams. It can be used for a multitude of fire management applications including projecting the behavior of an ongoing fire, planning...

  15. Fire models for assessment of nuclear power plant fires

    SciTech Connect

    Nicolette, V.F.; Nowlen, S.P.

    1989-01-01

    This paper reviews the state-of-the-art in available fire models for the assessment of nuclear power plants fires. The advantages and disadvantages of three basic types of fire models (zone, field, and control volume) and Sandia's experience with these models will be discussed. It is shown that the type of fire model selected to solve a particular problem should be based on the information that is required. Areas of concern which relate to all nuclear power plant fire models are identified. 17 refs., 6 figs.

  16. Decision modeling for analyzing fire action outcomes

    Treesearch

    Donald MacGregor; Armando Gonzalez-Caban

    2008-01-01

    A methodology for incident decomposition and reconstruction is developed based on the concept of an "event-frame model." The event-frame model characterizes a fire incident in terms of (a) environmental events that pertain to the fire and the fire context (e.g., fire behavior, weather, fuels) and (b) management events that represent responses to the fire...

  17. Efficient computation of the maximum a posteriori path and parameter estimation in integrate-and-fire and more general state-space models.

    PubMed

    Koyama, Shinsuke; Paninski, Liam

    2010-08-01

    A number of important data analysis problems in neuroscience can be solved using state-space models. In this article, we describe fast methods for computing the exact maximum a posteriori (MAP) path of the hidden state variable in these models, given spike train observations. If the state transition density is log-concave and the observation model satisfies certain standard assumptions, then the optimization problem is strictly concave and can be solved rapidly with Newton-Raphson methods, because the Hessian of the loglikelihood is block tridiagonal. We can further exploit this block-tridiagonal structure to develop efficient parameter estimation methods for these models. We describe applications of this approach to neural decoding problems, with a focus on the classic integrate-and-fire model as a key example.

  18. A computer simulation of aircraft evacuation with fire

    NASA Technical Reports Server (NTRS)

    Middleton, V. E.

    1983-01-01

    A computer simulation was developed to assess passenger survival during the post-crash evacuation of a transport category aircraft when fire is a major threat. The computer code, FIREVAC, computes individual passenger exit paths and times to exit, taking into account delays and congestion caused by the interaction among the passengers and changing cabin conditions. Simple models for the physiological effects of the toxic cabin atmosphere are included with provision for including more sophisticated models as they become available. Both wide-body and standard-body aircraft may be simulated. Passenger characteristics are assigned stochastically from experimentally derived distributions. Results of simulations of evacuation trials and hypothetical evacuations under fire conditions are presented.

  19. Active fire detection using a peat fire radiance model

    NASA Astrophysics Data System (ADS)

    Kushida, K.; Honma, T.; Kaku, K.; Fukuda, M.

    2011-12-01

    The fire fractional area and radiances at 4 and 11 μm of active fires in Indonesia were estimated using Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) images. Based on these fire information, a stochastic fire model was used for evaluating two fire detection algorithms of Moderate Resolution Imaging Spectroradiometer (MODIS). One is single-image stochastic fire detection, and the other is multitemporal stochastic fire detection (Kushida, 2010 - IEEE Geosci. Remote Sens. Lett.). The average fire fractional area per one 1 km2 ×1 km2 pixel was 1.7%; this value corresponds to 32% of that of Siberian and Mongolian boreal forest fires. The average radiances at 4 and 11 μm of active fires were 7.2 W/(m2.sr.μm) and 11.1 W/(m2.sr.μm); these values correspond to 47% and 91% of those of Siberian and Mongolian boreal forest fires, respectively. In order to get false alarms less than 20 points per 106 km2 area, for the Siberian and Mongolian boreal forest fires, omission errors (OE) of 50-60% and about 40% were expected for the detections by using the single and multitemporal images, respectively. For Indonesian peat fires, OE of 80-90% was expected for the detections by using the single images. For the peat-fire detections by using the multitemporal images, OE of about 40% was expected, provided that the background radiances were estimated from past multitemporal images with less than the standard deviation of 1K. The analyses indicated that it was difficult to obtain sufficient active-fire information of Indonesian peat fires from single MODIS images for the fire fighting, and that the use of the multitemporal images was important.

  20. Data for Room Fire Model Comparisons

    PubMed Central

    Peacock, Richard D.; Davis, Sanford; Babrauskas, Vytenis

    1991-01-01

    With the development of models to predict fire growth and spread in buildings, there has been a concomitant evolution in the measurement and analysis of experimental data in real-scale fires. This report presents the types of analyses that can be used to examine large-scale room fire test data to prepare the data for comparison with zone-based fire models. Five sets of experimental data which can be used to test the limits of a typical two-zone fire model are detailed. A standard set of nomenclature describing the geometry of the building and the quantities measured in each experiment is presented. Availability of ancillary data (such as smaller-scale test results) is included. These descriptions, along with the data (available in computer-readable form) should allow comparisons between the experiment and model predictions. The base of experimental data ranges in complexity from one room tests with individual furniture items to a series of tests conducted in a multiple story hotel equipped with a zoned smoke control system. PMID:28184121

  1. WRF-Fire: coupled weather-wildland fire modeling with the weather research and forecasting model

    Treesearch

    Janice L. Coen; Marques Cameron; John Michalakes; Edward G. Patton; Philip J. Riggan; Kara M. Yedinak

    2012-01-01

    A wildland fire behavior module (WRF-Fire) was integrated into the Weather Research and Forecasting (WRF) public domain numerical weather prediction model. The fire module is a surface fire behavior model that is two-way coupled with the atmospheric model. Near-surface winds from the atmospheric model are interpolated to a finer fire grid and used, with fuel properties...

  2. First Order Fire Effects Model: FOFEM 4.0, user's guide

    Treesearch

    Elizabeth D. Reinhardt; Robert E. Keane; James K. Brown

    1997-01-01

    A First Order Fire Effects Model (FOFEM) was developed to predict the direct consequences of prescribed fire and wildfire. FOFEM computes duff and woody fuel consumption, smoke production, and fire-caused tree mortality for most forest and rangeland types in the United States. The model is available as a computer program for PC or Data General computer.

  3. Integrating Fire Effects into an Ecohydrologic Model for Simulating Fire Regimes

    NASA Astrophysics Data System (ADS)

    Bart, R. R.; Tague, C.; Kennedy, M. C.; McKenzie, D.

    2016-12-01

    Ecohydrologic models are used to dynamically simulate vegetation growth/ mortality and their interaction with water and nutrient fluxes. Although disturbances such as wildfire are a natural part of the landscape in environments such as the Western US, wildfire is generally included only as an exogenous variable in ecohydrologic models. An alternative approach is to integrate wildfire directly into ecohydrologic models so that wildfire ignition, spread and effects are driven by simulated landscape conditions within the model. This approach allows for the simulation of natural fire regimes and may provide more robust estimates of long-term ecological variables such as forest health, carbon sequestration and water use. For this study, we detail a fire-effects model that has been developed to couple a fire-spread model, WMFire, with an ecohydrologic model, RHESSys. The fire-effects model is designed for use with a simple two-stratum representation of canopy structure and computes losses following fire spread to a given landscape patch. Losses to a modeled litter layer, coarse woody debris layer and understory vegetation layer are determined based on a patch-level integrated measure of fuel loads, moisture levels, wind speed, and topography. Losses to an overstory vegetation layer are based on understory biomass consumed by the wildfire. The fire effects model was found to replicate the expected impacts of wildfire on vegetation and litter. Further, the fully coupled RHESSys-WMFire model was tested in four Western US watersheds with different vegetation/climate/fire characteristics and preliminary results indicated that the model was able to reproduce the disparate fire regimes. We highlight remaining challenges with simulating fire effects in ecohydrologic models using simplified representations of canopy structures and litter fuels. This study demonstrates the potential for integrating fire into ecohydrologic models for simulating future fire regimes.

  4. Forest Fire History... A Computer Method of Data Analysis

    Treesearch

    Romain M. Meese

    1973-01-01

    A series of computer programs is available to extract information from the individual Fire Reports (U.S. Forest Service Form 5100-29). The programs use a statistical technique to fit a continuous distribution to a set of sampled data. The goodness-of-fit program is applicable to data other than the fire history. Data summaries illustrate analysis of fire occurrence,...

  5. Modelling Technology for Building Fire Scene with Virtual Geographic Environment

    NASA Astrophysics Data System (ADS)

    Song, Y.; Zhao, L.; Wei, M.; Zhang, H.; Liu, W.

    2017-09-01

    Building fire is a risky activity that can lead to disaster and massive destruction. The management and disposal of building fire has always attracted much interest from researchers. Integrated Virtual Geographic Environment (VGE) is a good choice for building fire safety management and emergency decisions, in which a more real and rich fire process can be computed and obtained dynamically, and the results of fire simulations and analyses can be much more accurate as well. To modelling building fire scene with VGE, the application requirements and modelling objective of building fire scene were analysed in this paper. Then, the four core elements of modelling building fire scene (the building space environment, the fire event, the indoor Fire Extinguishing System (FES) and the indoor crowd) were implemented, and the relationship between the elements was discussed also. Finally, with the theory and framework of VGE, the technology of building fire scene system with VGE was designed within the data environment, the model environment, the expression environment, and the collaborative environment as well. The functions and key techniques in each environment are also analysed, which may provide a reference for further development and other research on VGE.

  6. Simulating initial attack with two fire containment models

    Treesearch

    Romain M. Mees

    1985-01-01

    Given a variable rate of fireline construction and an elliptical fire growth model, two methods for estimating the required number of resources, time to containment, and the resulting fire area were compared. Five examples illustrate some of the computational differences between the simple and the complex methods. The equations for the two methods can be used and...

  7. Retrospective fire modeling: Quantifying the impacts of fire suppression

    Treesearch

    Brett H. Davis; Carol Miller; Sean A. Parks

    2010-01-01

    Land management agencies need to understand and monitor the consequences of their fire suppression decisions. We developed a framework for retrospective fire behavior modeling and impact assessment to determine where ignitions would have spread had they not been suppressed and to assess the cumulative effects that would have resulted. This document is a general...

  8. A hierarchical fire frequency model to simulate temporal patterns of fire regimes in LANDIS

    Treesearch

    Jian Yang; Hong S. He; Eric J. Gustafson

    2004-01-01

    Fire disturbance has important ecological effects in many forest landscapes. Existing statistically based approaches can be used to examine the effects of a fire regime on forest landscape dynamics. Most examples of statistically based fire models divide a fire occurrence into two stages--fire ignition and fire initiation. However, the exponential and Weibull fire-...

  9. Stochastic representation of fire behavior in a wildland fire protection planning model for California.

    Treesearch

    J. Keith Gilless; Jeremy S. Fried

    1998-01-01

    A fire behavior module was developed for the California Fire Economics Simulator version 2 (CFES2), a stochastic simulation model of initial attack on wildland fire used by the California Department of Forestry and Fire Protection. Fire rate of spread (ROS) and fire dispatch level (FDL) for simulated fires "occurring" on the same day are determined by making...

  10. Decision modeling for fire incident analysis

    Treesearch

    Donald G. MacGregor; Armando González-Cabán

    2009-01-01

    This paper reports on methods for representing and modeling fire incidents based on concepts and models from the decision and risk sciences. A set of modeling techniques are used to characterize key fire management decision processes and provide a basis for incident analysis. The results of these methods can be used to provide insights into the structure of fire...

  11. Probability model for analyzing fire management alternatives: theory and structure

    Treesearch

    Frederick W. Bratten

    1982-01-01

    A theoretical probability model has been developed for analyzing program alternatives in fire management. It includes submodels or modules for predicting probabilities of fire behavior, fire occurrence, fire suppression, effects of fire on land resources, and financial effects of fire. Generalized "fire management situations" are used to represent actual fire...

  12. Modeling boreal fire and forest dynamics

    NASA Astrophysics Data System (ADS)

    de Groot, W. J.; McRae, D. J.; Cantin, A.

    2009-04-01

    The circumpolar boreal forest covers about 1.4 billion ha, representing 1/3 of global forest land. Approximately 2/3 of the boreal forest is located in Eurasia and the remainder in North America. Wildland fires annually burn an estimated 12-20 M ha across the entire boreal region, having a major influence on forest structure and composition. However, fire weather, fire behaviour, and fire ecology differ greatly between the boreal forests in eastern and western hemispheres, which have significant impact on tree survival, post-fire regeneration and forest succession. Every year, wildland fires in Canada and Alaska burn an average of 2-3 M ha, primarily by stand-replacing, high intensity crown fires. By comparison, Russian fires burn about 10-15 M ha annually, primarily by low to moderate intensity surface fires that cause minimal tree mortality. Fire weather conditions in the most fire prone regions of Russia are generally more severe than in similar regions of North America. Finally, the species composition of eastern and western boreal forests is also very different. Russian forests are dominated by larch (30%) and pine (28%) with lower components of spruce (14%) and poplar/birch hardwoods (18%) By contrast, Canadian forests are comprised mainly of spruce (35%), pine (22%), poplar/birch (16%), and fir (9%). All of these factors contribute to the variability in vegetation dynamics occurring within the circumpolar boreal region. This modeling study examines the interactions of fire weather, forest composition, fire behaviour, and fire ecology on forest vegetation dynamics within the boreal region. Similar active fire zones in western Canada and eastern Siberia were used as study sites. Historical weather data were collected for both locations and used to calculate fire weather data, which were used as primary driving variables for the Boreal Fire Effects model (BORFIRE). Fire behaviour was calculated in BORFIRE using data for major tree species at both study sites

  13. BehavePlus fire modeling system: Past, present, and future

    Treesearch

    Patricia L. Andrews

    2007-01-01

    Use of mathematical fire models to predict fire behavior and fire effects plays an important supporting role in wildland fire management. When used in conjunction with personal fire experience and a basic understanding of the fire models, predictions can be successfully applied to a range of fire management activities including wildfire behavior prediction, prescribed...

  14. Standard fire behavior fuel models: a comprehensive set for use with Rothermel's surface fire spread model

    Treesearch

    Joe H. Scott; Robert E. Burgan

    2005-01-01

    This report describes a new set of standard fire behavior fuel models for use with Rothermel's surface fire spread model and the relationship of the new set to the original set of 13 fire behavior fuel models. To assist with transition to using the new fuel models, a fuel model selection guide, fuel model crosswalk, and set of fuel model photos are provided.

  15. Fire Modeling Institute 2011 Annual Report

    Treesearch

    Robin J. Innes

    2012-01-01

    The Fire Modeling Institute (FMI), a part of the Rocky Mountain Research Station, Fire, Fuel, and Smoke Science Program, provides a bridge between scientists and managers. The mission of FMI is to bring the best available science and technology developed throughout the research community to bear on fire-related management issues across the nation. Resource management...

  16. BehavePlus fire modeling system, version 5.0: Variables

    Treesearch

    Patricia L. Andrews

    2009-01-01

    This publication has been revised to reflect updates to version 4.0 of the BehavePlus software. It was originally published as the BehavePlus fire modeling system, version 4.0: Variables in July, 2008.The BehavePlus fire modeling system is a computer program based on mathematical models that describe wildland fire behavior and effects and the...

  17. Numerical field model simulation of full scale fire tests in a closed spherical/cylindrical vessel

    NASA Astrophysics Data System (ADS)

    Raycraft, Janet K.

    1987-12-01

    Most of the casualties incurred during a fire are due to the smoke generated. An understanding of the way smoke and fire spread during a fire would provide a valuable tool to save lives and minimize damage. The Naval Research Laboratory maintains a full scale test facility called Fire-1. The computer model developed in this thesis is based on the actual geometry of Fire-1 and uses field modeling. It is a three dimensional, finite difference model using primitive variables. The model includes local and global pressure corrections, surface radiation, turbulence, strong buoyancy, and conjugate boundary conditions. Given heat input data, the computer code produces pressure, temperature, density, and velocity fields. Experimental fire tests conducted in Fire-1 are used to validate the computer code. Reasonable agreement in the results has been found. Because of the model's ability to account for pressure, temperature and smoke buildup, its envisioned use is to predict fires aboard ships and submarines.

  18. Performance of fire behavior fuel models developed for the Rothermel Surface Fire Spread Model

    Treesearch

    Robert Ziel; W. Matt Jolly

    2009-01-01

    In 2005, 40 new fire behavior fuel models were published for use with the Rothermel Surface Fire Spread Model. These new models are intended to augment the original 13 developed in 1972 and 1976. As a compiled set of quantitative fuel descriptions that serve as input to the Rothermel model, the selected fire behavior fuel model has always been critical to the resulting...

  19. FIRE

    Atmospheric Science Data Center

    2017-03-16

    Projects:  FIRE Definition/Description:  The F irst I SCCP R egional E xperiments (FIRE) have been designed to improve data products and cloud/radiation ... circulation models (GCMs). Specifically, the goals of FIRE are (1) to improve basic understanding of the interaction of physical ...

  20. Users manual for CAFE-3D : a computational fluid dynamics fire code.

    SciTech Connect

    Khalil, Imane; Lopez, Carlos; Suo-Anttila, Ahti Jorma

    2005-03-01

    The Container Analysis Fire Environment (CAFE) computer code has been developed to model all relevant fire physics for predicting the thermal response of massive objects engulfed in large fires. It provides realistic fire thermal boundary conditions for use in design of radioactive material packages and in risk-based transportation studies. The CAFE code can be coupled to commercial finite-element codes such as MSC PATRAN/THERMAL and ANSYS. This coupled system of codes can be used to determine the internal thermal response of finite element models of packages to a range of fire environments. This document is a user manual describing how to use the three-dimensional version of CAFE, as well as a description of CAFE input and output parameters. Since this is a user manual, only a brief theoretical description of the equations and physical models is included.

  1. Ionic currents influencing spontaneous firing and pacemaker frequency in dopamine neurons of the ventrolateral periaqueductal gray and dorsal raphe nucleus (vlPAG/DRN): A voltage-clamp and computational modelling study.

    PubMed

    Dougalis, Antonios G; Matthews, Gillian A C; Liss, Birgit; Ungless, Mark A

    2017-04-03

    Dopamine (DA) neurons of the ventrolateral periaqueductal gray (vlPAG) and dorsal raphe nucleus (DRN) fire spontaneous action potentials (APs) at slow, regular patterns in vitro but a detailed account of their intrinsic membrane properties responsible for spontaneous firing is currently lacking. To resolve this, we performed a voltage-clamp electrophysiological study in brain slices to describe their major ionic currents and then constructed a computer model and used simulations to understand the mechanisms behind autorhythmicity in silico. We found that vlPAG/DRN DA neurons exhibit a number of voltage-dependent currents activating in the subthreshold range including, a hyperpolarization-activated cation current (IH), a transient, A-type, potassium current (IA), a background, 'persistent' (INaP) sodium current and a transient, low voltage activated (LVA) calcium current (ICaLVA). Brain slice pharmacology, in good agreement with computer simulations, showed that spontaneous firing occurred independently of IH, IA or calcium currents. In contrast, when blocking sodium currents, spontaneous firing ceased and a stable, non-oscillating membrane potential below AP threshold was attained. Using the DA neuron model we further show that calcium currents exhibit little activation (compared to sodium) during the interspike interval (ISI) repolarization while, any individual potassium current alone, whose blockade positively modulated AP firing frequency, is not required for spontaneous firing. Instead, blockade of a number of potassium currents simultaneously is necessary to eliminate autorhythmicity. Repolarization during ISI is mediated initially via the deactivation of the delayed rectifier potassium current, while a sodium background 'persistent' current is essentially indispensable for autorhythmicity by driving repolarization towards AP threshold.

  2. Calculation of shipboard fire conditions for radioactive materials packages with the methods of computational fluid dynamics

    SciTech Connect

    Koski, J.A.; Wix, S.D.; Cole, J.K.

    1997-09-01

    Shipboard fires both in the same ship hold and in an adjacent hold aboard a break-bulk cargo ship are simulated with a commercial finite-volume computational fluid mechanics code. The fire models and modeling techniques are described and discussed. Temperatures and heat fluxes to a simulated materials package are calculated and compared to experimental values. The overall accuracy of the calculations is assessed.

  3. Differences in simulated fire spread over Askervein Hill using two advanced wind models and a traditional uniform wind field

    Treesearch

    Jason Forthofer; Bret Butler

    2007-01-01

    A computational fluid dynamics (CFD) model and a mass-consistent model were used to simulate winds on simulated fire spread over a simple, low hill. The results suggest that the CFD wind field could significantly change simulated fire spread compared to traditional uniform winds. The CFD fire spread case may match reality better because the winds used in the fire...

  4. Assessing crown fire potential by linking models of surface and crown fire behavior

    Treesearch

    Joe H. Scott; Elizabeth D. Reinhardt

    2001-01-01

    Fire managers are increasingly concerned about the threat of crown fires, yet only now are quantitative methods for assessing crown fire hazard being developed. Links among existing mathematical models of fire behavior are used to develop two indices of crown fire hazard-the Torching Index and Crowning Index. These indices can be used to ordinate different forest...

  5. Fire and materials modeling for transportation systems

    SciTech Connect

    Skocypec, R.D.; Gritzo, L.A.; Moya, J.L.; Nicolette, V.F.; Tieszen, S.R.; Thomas, R.

    1994-10-01

    Fire is an important threat to the safety of transportation systems. Therefore, understanding the effects of fire (and its interaction with materials) on transportation systems is crucial to quantifying and mitigating the impact of fire on the safety of those systems. Research and development directed toward improving the fire safety of transportation systems must address a broad range of phenomena and technologies, including: crash dynamics, fuel dispersion, fire environment characterization, material characterization, and system/cargo thermal response modeling. In addition, if the goal of the work is an assessment and/or reduction of risk due to fires, probabilistic risk assessment technology is also required. The research currently underway at Sandia National Laboratories in each of these areas is summarized in this paper.

  6. Modelling public support for wildland fire policy

    Treesearch

    J.D. Absher; J.J. Vaske

    2007-01-01

    Theoretically grounded explanations of wildland fire policy can be improved by empirically documenting the causal influences of support for (or opposition to) management alternatives. This chapter proposes a model based on the specificity principle (i.e. correspondence between measured variables to empirically examine four common wildland fire policies in relation to...

  7. Risk assessment compatible fire models (RACFMs)

    SciTech Connect

    Lopez, A.R.; Gritzo, L.A.; Sherman, M.P.

    1998-07-01

    A suite of Probabilistic Risk Assessment Compatible Fire Models (RACFMs) has been developed to represent the hazard posed by a pool fire to weapon systems transported on the B52-H aircraft. These models represent both stand-off (i.e., the weapon system is outside of the flame zone but exposed to the radiant heat load from fire) and fully-engulfing scenarios (i.e., the object is fully covered by flames). The approach taken in developing the RACFMs for both scenarios was to consolidate, reconcile, and apply data and knowledge from all available resources including: data and correlations from the literature, data from an extensive full-scale fire test program at the Naval Air Warfare Center (NAWC) at China Lake, and results from a fire field model (VULCAN). In the past, a single, effective temperature, T{sub f}, was used to represent the fire. The heat flux to an object exposed to a fire was estimated using the relationship for black body radiation, {sigma}T{sub f}{sup 4}. Significant improvements have been made by employing the present approach which accounts for the presence of temperature distributions in fully-engulfing fires, and uses best available correlations to estimate heat fluxes in stand-off scenarios.

  8. An Overview of FlamMap Fire Modeling Capabilities

    Treesearch

    Mark A. Finney

    2006-01-01

    Computerized and manual systems for modeling wildland fire behavior have long been available (Rothermel 1983, Andrews 1986). These systems focus on one-dimensional behaviors and assume the fire geometry is a spreading line-fire (in contrast with point or area-source fires). Models included in these systems were developed to calculate fire spread rate (Rothermel 1972,...

  9. Using HFire for spatial modeling of fire in shrublands

    Treesearch

    Seth H. Peterson; Marco E. Morais; Jean M. Carlson; Philip E. Dennison; Dar A. Roberts; Max A. Moritz; David R. Weise

    2009-01-01

    An efficient raster fire-spread model named HFire is introduced. HFire can simulate single-fire events or long-term fire regimes, using the same fire-spread algorithm. This paper describes the HFire algorithm, benchmarks the model using a standard set of tests developed for FARSITE, and compares historical and predicted fire spread perimeters for three southern...

  10. Employing Numerical Weather Models to Enhance Fire Weather and Fire Behavior Predictions

    Treesearch

    Joseph J. Charney; Lesley A. Fusina

    2006-01-01

    This paper presents an assessment of fire weather and fire behavior predictions produced by a numerical weather prediction model similar to those used by operational weather forecasters when preparing their forecasts. The PSU/NCAR MM5 model is used to simulate the weather conditions associated with three fire episodes in June 2005. Extreme fire behavior was reported...

  11. Comparison of crown fire modeling systems used in three fire management applications

    Treesearch

    Joe H. Scott

    2006-01-01

    The relative behavior of surface-crown fire spread rate modeling systems used in three fire management applications-CFIS (Crown Fire Initiation and Spread), FlamMap and NEXUS- is compared using fire environment characteristics derived from a dataset of destructively measured canopy fuel and associated stand characteristics. Although the surface-crown modeling systems...

  12. An effective wind speed for models of fire spread

    Treesearch

    Ralph M. Nelson

    2002-01-01

    In previous descriptions of wind-slope interaction and the spread rate of wildland fires it is assumed that the separate effects of wind and slope are independent and additive and that corrections for these effects may be applied to spread rates computed from existing rate of spread models. A different approach is explored in the present paper in which the upslope...

  13. Validation of coupled atmosphere-fire behavior models

    SciTech Connect

    Bossert, J.E.; Reisner, J.M.; Linn, R.R.; Winterkamp, J.L.; Schaub, R.; Riggan, P.J.

    1998-12-31

    Recent advances in numerical modeling and computer power have made it feasible to simulate the dynamical interaction and feedback between the heat and turbulence induced by wildfires and the local atmospheric wind and temperature fields. At Los Alamos National Laboratory, the authors have developed a modeling system that includes this interaction by coupling a high resolution atmospheric dynamics model, HIGRAD, with a fire behavior model, BEHAVE, to predict the spread of wildfires. The HIGRAD/BEHAVE model is run at very high resolution to properly resolve the fire/atmosphere interaction. At present, these coupled wildfire model simulations are computationally intensive. The additional complexity of these models require sophisticated methods for assuring their reliability in real world applications. With this in mind, a substantial part of the research effort is directed at model validation. Several instrumented prescribed fires have been conducted with multi-agency support and participation from chaparral, marsh, and scrub environments in coastal areas of Florida and inland California. In this paper, the authors first describe the data required to initialize the components of the wildfire modeling system. Then they present results from one of the Florida fires, and discuss a strategy for further testing and improvement of coupled weather/wildfire models.

  14. Modeling and Analysis of Realistic Fire Scenarios in Spacecraft

    NASA Technical Reports Server (NTRS)

    Brooker, J. E.; Dietrich, D. L.; Gokoglu, S. A.; Urban, D. L.; Ruff, G. A.

    2015-01-01

    An accidental fire inside a spacecraft is an unlikely, but very real emergency situation that can easily have dire consequences. While much has been learned over the past 25+ years of dedicated research on flame behavior in microgravity, a quantitative understanding of the initiation, spread, detection and extinguishment of a realistic fire aboard a spacecraft is lacking. Virtually all combustion experiments in microgravity have been small-scale, by necessity (hardware limitations in ground-based facilities and safety concerns in space-based facilities). Large-scale, realistic fire experiments are unlikely for the foreseeable future (unlike in terrestrial situations). Therefore, NASA will have to rely on scale modeling, extrapolation of small-scale experiments and detailed numerical modeling to provide the data necessary for vehicle and safety system design. This paper presents the results of parallel efforts to better model the initiation, spread, detection and extinguishment of fires aboard spacecraft. The first is a detailed numerical model using the freely available Fire Dynamics Simulator (FDS). FDS is a CFD code that numerically solves a large eddy simulation form of the Navier-Stokes equations. FDS provides a detailed treatment of the smoke and energy transport from a fire. The simulations provide a wealth of information, but are computationally intensive and not suitable for parametric studies where the detailed treatment of the mass and energy transport are unnecessary. The second path extends a model previously documented at ICES meetings that attempted to predict maximum survivable fires aboard space-craft. This one-dimensional model implies the heat and mass transfer as well as toxic species production from a fire. These simplifications result in a code that is faster and more suitable for parametric studies (having already been used to help in the hatch design of the Multi-Purpose Crew Vehicle, MPCV).

  15. Geospatial modeling of fire-size distributions in historical low-severity fire regimes

    NASA Astrophysics Data System (ADS)

    McKenzie, D.; Kellogg, L. B.; Larkin, N. K.

    2006-12-01

    Low-severity fires are recorded by fire-scarred trees. These records can provide temporal depth for reconstructing fire history because one tree may record dozens of separate fires over time, thereby providing adequate sample size for estimating fire frequency. Estimates of actual fire perimeters from these point-based records are uncertain, however, because fire boundaries can only be located approximately. We indirectly estimate fire-size distributions without attempting to establish individual fire perimeters. The slope and intercept of the interval-area function, a power-law relationship between sample area and mean fire-free intervals for that area, provide surrogates for the moments of a fire-size distribution, given a distribution of fire- free intervals. Analogously, by deconstructing variograms that use a binary distance measure (Sorensen's index) for the similarity of the time-series of fires recorded by pairs of recorder trees, we provide estimates of modal fire size. We link both variograms and interval-area functions to fire size distributions by simulating fire size distributions on neutral landscapes with and without right- censoring to represent topographic controls on maximum fire size. From parameters of the two functions produced by simulations we can back-estimate means and variances of fire sizes on real landscapes. This scale-based modeling provides a robust alternative to empirical and heuristic methods and a means to extrapolate estimates of fire-size distributions to unsampled landscapes.

  16. Aids to determining fuel models for estimating fire behavior

    Treesearch

    Hal E. Anderson

    1982-01-01

    Presents photographs of wildland vegetation appropriate for the 13 fuel models used in mathematical models of fire behavior. Fuel model descriptions include fire behavior associated with each fuel and its physical characteristics. A similarity chart cross-references the 13 fire behavior fuel models to the 20 fuel models used in the National Fire Danger Rating System....

  17. Laboratory Modeling of Aspects of Large Fires,

    DTIC Science & Technology

    1984-04-30

    7 -7 g~L AD-A153 152 DNA-TR- 84-18 LABORATORY MODELING OF ASPECTS OF LARGE FIRES G.F. Carrier "URARY F.E. Fendell b DVSO R.D. Fleeter N. Got L.M...I1I TITLE (include Socurty Olassihicarion) LABORATORY MODELING OF ASPECTS OF LARGE FIRES 12. PERSONAL AUrHoR(S G.F. Carrier F.E. Fendell R.D. Fleeter N...Motorbuch Verlag.___ Caidin, M. (1960). A Torch to the Enemy: the Fire Raid on Tokyo. New York, NY: Ballantine. Carrier, G. F., Fendell , F. E., and

  18. A method for mapping fire hazard and risk across multiple scales and its application in fire management

    Treesearch

    Robert E. Keane; Stacy A. Drury; Eva C. Karau; Paul F. Hessburg; Keith M. Reynolds

    2010-01-01

    This paper presents modeling methods for mapping fire hazard and fire risk using a research model called FIREHARM (FIRE Hazard and Risk Model) that computes common measures of fire behavior, fire danger, and fire effects to spatially portray fire hazard over space. FIREHARM can compute a measure of risk associated with the distribution of these measures over time using...

  19. Simulating wall and corner fire tests on wood products with the OSU room fire model

    Treesearch

    H. C. Tran

    1994-01-01

    This work demonstrates the complexity of modeling wall and corner fires in a compartment. The model chosen for this purpose is the Ohio State University (OSU) room fire model. This model was designed to simulate fire growth on walls in a compartment and therefore lends itself to direct comparison with standard room test results. The model input were bench-scale data...

  20. Evaluation of MM5 model resolution when applied to prediction of national fire danger rating indexes

    Treesearch

    Jeanne L. Hoadley; Miriam L. Rorig; Larry Bradshaw; Sue A. Ferguson; Kenneth J. Westrick; Scott L. Goodrick; Paul Werth

    2006-01-01

    Weather predictions from the MM5 mesoscale model were used to compute gridded predictions of National Fire Danger Rating System (NFDRS) indexes. The model output was applied to a case study of the 2000 fire season in Northern Idaho and Western Montana to simulate an extreme event. To determine the preferred resolution for automating NFD RS predictions, model...

  1. Fire modeling of the Heiss Dampf Reaktor containment

    SciTech Connect

    Nicolette, V.F.; Yang, K.T.

    1995-09-01

    This report summarizes Sandia National Laboratories` participation in the fire modeling activities for the German Heiss Dampf Reaktor (HDR) containment building, under the sponsorship of the United States Nuclear Regulatory Commission. The purpose of this report is twofold: (1) to summarize Sandia`s participation in the HDR fire modeling efforts and (2) to summarize the results of the international fire modeling community involved in modeling the HDR fire tests. Additional comments, on the state of fire modeling and trends in the international fire modeling community are also included. It is noted that, although the trend internationally in fire modeling is toward the development of the more complex fire field models, each type of fire model has something to contribute to the understanding of fires in nuclear power plants.

  2. A hydroclimatic model of global fire patterns

    NASA Astrophysics Data System (ADS)

    Boer, Matthias

    2015-04-01

    Satellite-based earth observation is providing an increasingly accurate picture of global fire patterns. The highest fire activity is observed in seasonally dry (sub-)tropical environments of South America, Africa and Australia, but fires occur with varying frequency, intensity and seasonality in almost all biomes on Earth. The particular combination of these fire characteristics, or fire regime, is known to emerge from the combined influences of climate, vegetation, terrain and land use, but has so far proven difficult to reproduce by global models. Uncertainty about the biophysical drivers and constraints that underlie current global fire patterns is propagated in model predictions of how ecosystems, fire regimes and biogeochemical cycles may respond to projected future climates. Here, I present a hydroclimatic model of global fire patterns that predicts the mean annual burned area fraction (F) of 0.25° x 0.25° grid cells as a function of the climatic water balance. Following Bradstock's four-switch model, long-term fire activity levels were assumed to be controlled by fuel productivity rates and the likelihood that the extant fuel is dry enough to burn. The frequency of ignitions and favourable fire weather were assumed to be non-limiting at long time scales. Fundamentally, fuel productivity and fuel dryness are a function of the local water and energy budgets available for the production and desiccation of plant biomass. The climatic water balance summarizes the simultaneous availability of biologically usable energy and water at a site, and may therefore be expected to explain a significant proportion of global variation in F. To capture the effect of the climatic water balance on fire activity I focused on the upper quantiles of F, i.e. the maximum level of fire activity for a given climatic water balance. Analysing GFED4 data for annual burned area together with gridded climate data, I found that nearly 80% of the global variation in the 0.99 quantile of F

  3. Applications of Living Fire PRA models to Fire Protection Significance Determination Process in Taiwan

    SciTech Connect

    De-Cheng, Chen; Chung-Kung, Lo; Tsu-Jen, Lin; Ching-Hui, Wu; Lin, James C.

    2004-07-01

    The living fire probabilistic risk assessment (PRA) models for all three operating nuclear power plants (NPPs) in Taiwan had been established in December 2000. In that study, a scenario-based PRA approach was adopted to systematically evaluate the fire and smoke hazards and associated risks. Using these fire PRA models developed, a risk-informed application project had also been completed in December 2002 for the evaluation of cable-tray fire-barrier wrapping exemption. This paper presents a new application of the fire PRA models to fire protection issues using the fire protection significance determination process (FP SDP). The fire protection issues studied may involve the selection of appropriate compensatory measures during the period when an automatic fire detection or suppression system in a safety-related fire zone becomes inoperable. The compensatory measure can either be a 24-hour fire watch or an hourly fire patrol. The living fire PRA models were used to estimate the increase in risk associated with the fire protection issue in terms of changes in core damage frequency (CDF) and large early release frequency (LERF). In compliance with SDP at-power and the acceptance guidelines specified in RG 1.174, the fire protection issues in question can be grouped into four categories; red, yellow, white and green, in accordance with the guidelines developed for FD SDP. A 24-hour fire watch is suggested only required for the yellow condition, while an hourly fire patrol may be adopted for the white condition. More limiting requirement is suggested for the red condition, but no special consideration is needed for the green condition. For the calculation of risk measures, risk impacts from any additional fire scenarios that may have been introduced, as well as more severe initiating events and fire damages that may accompany the fire protection issue should be considered carefully. Examples are presented in this paper to illustrate the evaluation process. (authors)

  4. MODELING VENTILATION SYSTEM RESPONSE TO FIRE

    SciTech Connect

    Coutts, D

    2007-04-17

    Fires in facilities containing nuclear material have the potential to transport radioactive contamination throughout buildings and may lead to widespread downwind dispersal threatening both worker and public safety. Development and implementation of control strategies capable of providing adequate protection from fire requires realistic characterization of ventilation system response which, in turn, depends on an understanding of fire development timing and suppression system response. This paper discusses work in which published HEPA filter data was combined with CFAST fire modeling predictions to evaluate protective control strategies for a hypothetical DOE non-reactor nuclear facility. The purpose of this effort was to evaluate when safety significant active ventilation coupled with safety class passive ventilation might be a viable control strategy.

  5. BEHAVE: fire behavior prediction and fuel modeling system-BURN Subsystem, part 1

    Treesearch

    Patricia L. Andrews

    1986-01-01

    Describes BURN Subsystem, Part 1, the operational fire behavior prediction subsystem of the BEHAVE fire behavior prediction and fuel modeling system. The manual covers operation of the computer program, assumptions of the mathematical models used in the calculations, and application of the predictions.

  6. A fire management simulation model using stochastic arrival times

    Treesearch

    Eric L. Smith

    1987-01-01

    Fire management simulation models are used to predict the impact of changes in the fire management program on fire outcomes. As with all models, the goal is to abstract reality without seriously distorting relationships between variables of interest. One important variable of fire organization performance is the length of time it takes to get suppression units to the...

  7. On a stochastic leaky integrate-and-fire neuronal model.

    PubMed

    Buonocore, A; Caputo, L; Pirozzi, E; Ricciardi, L M

    2010-10-01

    The leaky integrate-and-fire neuronal model proposed in Stevens and Zador (1998), in which time constant and resting potential are postulated to be time dependent, is revisited within a stochastic framework in which the membrane potential is mathematically described as a gauss-diffusion process. The first-passage-time probability density, miming in such a context the firing probability density, is evaluated by either the Volterra integral equation of Buonocore, Nobile, and Ricciardi ( 1987 ) or, when possible, by the asymptotics of Giorno, Nobile, and Ricciardi (1990). The model examined here represents an extension of the classic leaky integrate-and-fire one based on the Ornstein-Uhlenbeck process in that it is in principle compatible with the inclusion of some other physiological characteristics such as relative refractoriness. It also allows finer tuning possibilities in view of its accounting for certain qualitative as well as quantitative features, such as the behavior of the time course of the membrane potential prior to firings and the computation of experimentally measurable statistical descriptors of the firing time: mean, median, coefficient of variation, and skewness. Finally, implementations of this model are provided in connection with certain experimental evidence discussed in the literature.

  8. Fire aerosol experiment and comparisons with computer code predictions

    NASA Astrophysics Data System (ADS)

    Gregory, W. S.; Nichols, B. D.; White, B. W.; Smith, P. R.; Leslie, I. H.; Corkran, J. R.

    1988-08-01

    Los Alamos National Laboratory, in cooperation with New Mexico State University, has carried on a series of tests to provide experimental data on fire-generated aerosol transport. These data will be used to verify the aerosol transport capabilities of the FIRAC computer code. FIRAC was developed by Los Alamos for the U.S. Nuclear Regulatory Commission. It is intended to be used by safety analysts to evaluate the effects of hypothetical fires on nuclear plants. One of the most significant aspects of this analysis deals with smoke and radioactive material movement throughout the plant. The tests have been carried out using an industrial furnace that can generate gas temperatures to 300 C. To date, we have used quartz aerosol with a median diameter of about 10 microns as the fire aerosol simulant. We also plan to use fire-generated aerosols of polystyrene and polymethyl methacrylate (PMMA). The test variables include two nominal gas flow rates (150 and 300 cu ft/min) and three nominal gas temperatures (ambient, 150 C, and 300 C). The test results are presented in the form of plots of aerosol deposition vs length of duct. In addition, the mass of aerosol caught in a high-efficiency particulate air (HEPA) filter during the tests is reported. The tests are simulated with the FIRAC code, and the results are compared with the experimental data.

  9. First order fire effects model: FOFEM 4.0, user`s guide. Forest Service general technical report

    SciTech Connect

    Reinhardt, E.D.; Keane, R.E.; Brown, J.K.

    1997-01-01

    A First Order Fire Effects Model (FOFEM) was developed to predict the direct consequences of prescribed fire and wildlife. FOFEM computes duff and woody fuel consumption, mineral soil exposure, fire-caused tree mortality, and smoke production for many forest and rangeland ecosystems. Quantitative results from many fire effects studies were summarized for inclusion into the model. FOFEM contains a fire effects calculator to predict the effects of a fire from the burning conditions necessary to achieve a desired effect. Default input values are derived from fuel models provided for natural and activity fuels by many forest cover types.

  10. Analytical modeling of fire growth on fire-resistive wood-based materials with changing conditions

    Treesearch

    Mark A. Dietenberger

    2006-01-01

    Our analytical model of fire growth for the ASTM E 84 tunnel, which simultaneously predicts heat release rate, flame-over area, and pyrolysis area as functions of time for constant conditions, was documented in the 2001 BCC Symposium for different treated wood materials. The model was extended to predict ignition and fire growth on exterior fire-resistive structures...

  11. Analysis of NASA JP-4 fire tests data and development of a simple fire model

    NASA Technical Reports Server (NTRS)

    Raj, P.

    1980-01-01

    The temperature, velocity and species concentration data obtained during the NASA fire tests (3m, 7.5m and 15m diameter JP-4 fires) were analyzed. Utilizing the data analysis, a sample theoretical model was formulated to predict the temperature and velocity profiles in JP-4 fires. The theoretical model, which does not take into account the detailed chemistry of combustion, is capable of predicting the extent of necking of the fire near its base.

  12. Conductance-based integrate-and-fire models.

    PubMed

    Destexhe, A

    1997-04-01

    A conductance-based model of Na+ and K+ currents underlying action potential generation is introduced by simplifying the quantitative model of Hodgkin and Huxley (HH). If the time course of rate constants can be approximated by a pulse, HH equations can be solved analytically. Pulse-based (PB) models generate action potentials very similar to the HH model but are computationally faster. Unlike the classical integrate-and-fire (IAF) approach, they take into account the changes of conductances during and after the spike, which have a determinant influence in shaping neuronal responses. Similarities and differences among PB, IAF, and HH models are illustrated for three cases: high-frequency repetitive firing, spike timing following random synaptic inputs, and network behavior in the presence of intrinsic currents.

  13. A neutral model of low-severity fire regimes

    Treesearch

    Don McKenzie; Amy E. Hessl

    2008-01-01

    Climate, topography, fuel loadings, and human activities all affect spatial and temporal patterns of fire occurrence. Because fire occurrence is a stochastic process, an understanding of baseline variability is necessary in order to identify constraints on surface fire regimes. With a suitable null, or neutral, model, characteristics of natural fire regimes estimated...

  14. Classifying and comparing spatial models of fire dynamics

    Treesearch

    Geoffrey J. Cary; Robert E. Keane; Mike D. Flannigan

    2007-01-01

    Wildland fire is a significant disturbance in many ecosystems worldwide and the interaction of fire with climate and vegetation over long time spans has major effects on vegetation dynamics, ecosystem carbon budgets, and patterns of biodiversity. Landscape-Fire-Succession Models (LFSMs) that simulate the linked processes of fire and vegetation development in a spatial...

  15. Fire and Smoke Model Evaluation Experiment (FASMEE): Modeling gaps and data needs

    Treesearch

    Yongqiang Liu; Adam Kochanski; Kirk Baker; Ruddy Mell; Rodman Linn; Ronan Paugam; Jan Mandel; Aime Fournier; Mary Ann Jenkins; Scott Goodrick; Gary Achtemeier; Andrew Hudak; Matthew Dickson; Brian Potter; Craig Clements; Shawn Urbanski; Roger Ottmar; Narasimhan Larkin; Timothy Brown; Nancy French; Susan Prichard; Adam Watts; Derek McNamara

    2017-01-01

    Fire and smoke models are numerical tools for simulating fire behavior, smoke dynamics, and air quality impacts of wildland fires. Fire models are developed based on the fundamental chemistry and physics of combustion and fire spread or statistical analysis of experimental data (Sullivan 2009). They provide information on fire spread and fuel consumption for safe and...

  16. Assessing skill of operational forest fire emissions model

    NASA Astrophysics Data System (ADS)

    Schultz, Colin

    2012-10-01

    Across the continental United States, the BlueSky Smoke Modeling Framework provides hourly forest fire emissions forecasts and calculates the concentrations of hazardous compounds 72 hours in advance. Though a traditional computational model itself, the BlueSky Framework pulls together the results from a number of different independent models for fire and fuel information, combustion of fuel, and speciated emissions calculations to produce its operational forecasts of fire-related emissions and smoke dispersals. One aspect of forest fire emissions that is of particular concern is small particulate matter, particularly microscopic particles with diameters less than 2.5 micrometers. These particles, known as PM2.5, are small enough to penetrate lung tissue and cause serious health problems in high concentrations. To assess the skill of the BlueSky Gateway, a system that uses the BlueSky Framework and the Community MultiScale Air Quality (CMAQ) model to forecast PM2.5 surface concentrations, Strand et al. compared the modeled estimates for two Californian forest wildfire events against observations.

  17. Resolving vorticity-driven lateral fire spread using the WRF-Fire coupled atmosphere-fire numerical model

    NASA Astrophysics Data System (ADS)

    Simpson, C. C.; Sharples, J. J.; Evans, J. P.

    2014-09-01

    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.

  18. Do you BEHAVE? - Application of the BehavePlus fire modeling system

    Treesearch

    Pat Andrews

    2010-01-01

    The BehavePlus fire modeling system is the successor to BEHAVE, which was first used in the field in 1984. It is public domain software, available for free use on personal computers. Information on user communities and fire management applications can be useful in designing next generation systems. Several sources of information about BehavePlus are summarized to...

  19. Room fire test for fire growth modeling : a sensitivity study

    Treesearch

    H. C. Tran; M. L. Janssens

    1989-01-01

    A room test designed according to the ASTM draft standard was used to investigate the effect of various parameters on the contribution of wall and corner fires to compartment fire growth. Location of the burner (against a wall or in a corner), power program of the gas burner ignition source, and combination of wall linings were varied, An initial series of calibration...

  20. Modeling regional-scale wildland fire emissions with the wildland fire emissions information system

    Treesearch

    Nancy H.F. French; Donald McKenzie; Tyler Erickson; Benjamin Koziol; Michael Billmire; K. Endsley; Naomi K.Y. Scheinerman; Liza Jenkins; Mary E. Miller; Roger Ottmar; Susan Prichard

    2014-01-01

    As carbon modeling tools become more comprehensive, spatial data are needed to improve quantitative maps of carbon emissions from fire. The Wildland Fire Emissions Information System (WFEIS) provides mapped estimates of carbon emissions from historical forest fires in the United States through a web browser. WFEIS improves access to data and provides a consistent...

  1. Numerical modeling of water spray suppression of conveyor belt fires in a large-scale tunnel.

    PubMed

    Yuan, Liming; Smith, Alex C

    2015-05-01

    Conveyor belt fires in an underground mine pose a serious life threat to miners. Water sprinkler systems are usually used to extinguish underground conveyor belt fires, but because of the complex interaction between conveyor belt fires and mine ventilation airflow, more effective engineering designs are needed for the installation of water sprinkler systems. A computational fluid dynamics (CFD) model was developed to simulate the interaction between the ventilation airflow, the belt flame spread, and the water spray system in a mine entry. The CFD model was calibrated using test results from a large-scale conveyor belt fire suppression experiment. Simulations were conducted using the calibrated CFD model to investigate the effects of sprinkler location, water flow rate, and sprinkler activation temperature on the suppression of conveyor belt fires. The sprinkler location and the activation temperature were found to have a major effect on the suppression of the belt fire, while the water flow rate had a minor effect.

  2. Numerical modeling of water spray suppression of conveyor belt fires in a large-scale tunnel

    PubMed Central

    Yuan, Liming; Smith, Alex C.

    2015-01-01

    Conveyor belt fires in an underground mine pose a serious life threat to miners. Water sprinkler systems are usually used to extinguish underground conveyor belt fires, but because of the complex interaction between conveyor belt fires and mine ventilation airflow, more effective engineering designs are needed for the installation of water sprinkler systems. A computational fluid dynamics (CFD) model was developed to simulate the interaction between the ventilation airflow, the belt flame spread, and the water spray system in a mine entry. The CFD model was calibrated using test results from a large-scale conveyor belt fire suppression experiment. Simulations were conducted using the calibrated CFD model to investigate the effects of sprinkler location, water flow rate, and sprinkler activation temperature on the suppression of conveyor belt fires. The sprinkler location and the activation temperature were found to have a major effect on the suppression of the belt fire, while the water flow rate had a minor effect. PMID:26190905

  3. Sensitivity of fire behavior simulations to fuel model variations

    Treesearch

    Lucy A. Salazar

    1985-01-01

    Stylized fuel models, or numerical descriptions of fuel arrays, are used as inputs to fire behavior simulation models. These fuel models are often chosen on the basis of generalized fuel descriptions, which are related to field observations. Site-specific observations of fuels or fire behavior in the field are not readily available or necessary for most fire management...

  4. Using burned area data to explore fire spread in coupled fire and ecosystem models

    NASA Astrophysics Data System (ADS)

    Gomez-Dans, J. L.; Lewis, P.; Wooster, M.; Spessa, A.

    2009-04-01

    Fire is a major driver of change in many ecosystems, and ecosystem models should try to understand and model the feedbacks between vegetation and fire. To achieve this, work has started on coupling fire and ecosystem models. The fire model receives modelled vegetation as input for its fuel loads, and simulates ignitions and fire spread from a number of assumptions on fire processes. The fire model simulates fire behaviour, and also estimates how vegetation is killed by the fire. This disturbance is fed back into the ecosystem model. In the current work, we focus on the LPJ ecosystem model and on the SPITFIRE fire model. Both models haven been used in conjunction in the past to model emissions over Southern Africa. SPITFIRE makes assumptions about ignitions (either anthropogenic or due to lightning strikes), live fuel moisture, fuel load and type derived from the ecosystem model, and about fire dynamics. In a typical run at daily temporal resolution, SPITFIRE will simulate an "average fire" in terms of fire dynamics, which is combined with the estimated daily number of ignitions to calculate the burned area on that day. The use of an average fire simplifies modelling at the coarse resolutions (grid cell spacing is often around 0.5 - 1 °) often used in these studies, but the associated penalty of a number of important fire limiting factors, such as human-driven suppression efforts or landscape elements that act as fire blocks. In the current study, we aim to explore landscape fragmentation in fire spread. To this end, we compare LPJ+SPITFIRE simulations fire area distributions with actual fire area observations from spaceborne sensors over a large region in Southern Africa. We introduce the concept of "landscape impedance", a metric that describes the difficulty of a fire spreading due to fragmentation, and estimate it spatially using satellite data. Finally, we introduce these concepts into the SPITFIRE fire model. Recently, burned area data from the MODIS sensor

  5. Modeling thermal protection outfits for fire exposures

    NASA Astrophysics Data System (ADS)

    Song, Guowen

    2002-01-01

    A numerical model has been developed that successfully predicts heat transfer through thermally protective clothing materials and garments exposed to intense heat. The model considers the effect of fire exposure to the thermophysical properties of materials as well as the air layers between the clothing material and skin surface. These experiments involved characterizing the flash fire surrounding the manikin by measuring the temperature of the flame above each thermal sensor in the manikin surface. An estimation method is used to calculate the heat transfer coefficient for each thermal sensor in a 4 second exposure to an average heat flux of 2.00cal/cm2sec. A parameter estimation method was used to estimate heat induced change in fabric thermophysical properties. The skin-clothe air gap distribution of different garments was determined using three-dimensional body scanning technology. Multi-layer skin model and a burn prediction method were used to predict second and third degree burns. The integrated generalized model developed was validated using the "Pyroman" Thermal Protective Clothing Analysis System with Kevlar/PBIRTM and NomexRTMIIIA coverall garments with different configuration and exposure time. A parametric study conducted using this numerical model indicated the influencing parameters on garment thermal protective performance in terms of skin burn damage subjected to 4 second flash fire exposure. The importance of these parameters is analyzed and distinguished. These parameters includes fabric thermophysical properties, PyromanRTM chamber flash fire characteristics, garment shrinkage and fit factors, as well as garment initial and test ambient temperature. Different skin models and their influence on burn prediction were also investigated using this model.

  6. Modelling the Meteorological Forest Fire Niche in Heterogeneous Pyrologic Conditions

    PubMed Central

    De Angelis, Antonella; Ricotta, Carlo; Conedera, Marco; Pezzatti, Gianni Boris

    2015-01-01

    Fire regimes are strongly related to weather conditions that directly and indirectly influence fire ignition and propagation. Identifying the most important meteorological fire drivers is thus fundamental for daily fire risk forecasting. In this context, several fire weather indices have been developed focussing mainly on fire-related local weather conditions and fuel characteristics. The specificity of the conditions for which fire danger indices are developed makes its direct transfer and applicability problematic in different areas or with other fuel types. In this paper we used the low-to-intermediate fire-prone region of Canton Ticino as a case study to develop a new daily fire danger index by implementing a niche modelling approach (Maxent). In order to identify the most suitable weather conditions for fires, different combinations of input variables were tested (meteorological variables, existing fire danger indices or a combination of both). Our findings demonstrate that such combinations of input variables increase the predictive power of the resulting index and surprisingly even using meteorological variables only allows similar or better performances than using the complex Canadian Fire Weather Index (FWI). Furthermore, the niche modelling approach based on Maxent resulted in slightly improved model performance and in a reduced number of selected variables with respect to the classical logistic approach. Factors influencing final model robustness were the number of fire events considered and the specificity of the meteorological conditions leading to fire ignition. PMID:25679957

  7. Modelling the meteorological forest fire niche in heterogeneous pyrologic conditions.

    PubMed

    De Angelis, Antonella; Ricotta, Carlo; Conedera, Marco; Pezzatti, Gianni Boris

    2015-01-01

    Fire regimes are strongly related to weather conditions that directly and indirectly influence fire ignition and propagation. Identifying the most important meteorological fire drivers is thus fundamental for daily fire risk forecasting. In this context, several fire weather indices have been developed focussing mainly on fire-related local weather conditions and fuel characteristics. The specificity of the conditions for which fire danger indices are developed makes its direct transfer and applicability problematic in different areas or with other fuel types. In this paper we used the low-to-intermediate fire-prone region of Canton Ticino as a case study to develop a new daily fire danger index by implementing a niche modelling approach (Maxent). In order to identify the most suitable weather conditions for fires, different combinations of input variables were tested (meteorological variables, existing fire danger indices or a combination of both). Our findings demonstrate that such combinations of input variables increase the predictive power of the resulting index and surprisingly even using meteorological variables only allows similar or better performances than using the complex Canadian Fire Weather Index (FWI). Furthermore, the niche modelling approach based on Maxent resulted in slightly improved model performance and in a reduced number of selected variables with respect to the classical logistic approach. Factors influencing final model robustness were the number of fire events considered and the specificity of the meteorological conditions leading to fire ignition.

  8. National Fire Fuels and Risks Assessment Using Remote Sensing and Ecological Modeling: Prototype Results

    NASA Astrophysics Data System (ADS)

    Zhu, Z.; Rollins, M.

    2003-12-01

    Hazardous fuel reduction, ecosystem rehabilitation and restoration, and firefighting safety, are land management priorities emphasized by recent national fire policies such as the National Fire Plan. Implementation of these policies requires geospatial data of vegetation conditions, fire fuels, risks, and ecosystem status developed consistently nationwide that can be used at multiple scales (i.e., local, regional, and national). A new research and development project called LANDFIRE has been conducted to develop an integrated methodology to produce geospatial fire data and predictive models for the land management community and a broad range of other applications. Main deliverables include mapped potential and existing vegetation types and structure variables, various biophysical data layers, fire fuels models, fire risk layers, as well as state-of-the-art computer models for assessing fire risk, behavior and effects. In this presentation, we will review research results and findings of the LANDFIRE project using results from a prototype study covering central Utah Uinta and Wasatch ecosystems. Particularly we will describe how a consistent and operational vegetation mapping component may be achieved by integrating machine-learning algorithms, field reference data, satellite imagery, and ecologically significant biophysical variables. We will discuss how remotely sensed vegetation cover types and structure can be successfully converted to fire fuel classes and risk layers which are necessary input into fire behavior and fire effect models. Finally we will discuss challenges and opportunities for national implementation of the methodology.

  9. National fire danger assessment and ecosystem restoration using remote sensing and ecological modeling

    NASA Astrophysics Data System (ADS)

    Zhu, Z.; Rollins, M.

    Hazardous fuel reduction, ecosystem rehabilitation and restoration, and firefighting safety, are land management priorities emphasized by recent national fire policies such as the National Fire Plan. Implementation of these policies requires geospatial data of vegetation conditions, fire fuels, risks, and ecosystem status developed consistently nationwide that can be used at multiple scales (i.e., local, regional, and national). A new research and development project called LANDFIRE is being conducted to develop an integrated methodology to produce geospatial fire data and predictive models for the land management community and a broad range of other applications. Main deliverables include mapped potential and existing vegetation types and vegetation structure parameters, various biophysical data layers, fire fuels models, fire risk layers, as well as state-of-the-art computer models for assessing fire risk, behavior and effects. In this presentation, we will review research results and findings of the LANDFIRE project using results from a prototype study covering central Utah Uinta and Wasatch ecosystems. Particularly we will describe how a consistent and operational vegetation mapping component may be achieved by integrating machine-learning algorithms, field reference data, satellite imagery, and ecologically significant biophysical variables. We will discuss how remotely sensed vegetation cover types and structure can be successfully converted to fire fuel classes and risk layers which are necessary input into fire behavior and fire effect models. Finally we will discuss challenges and opportunities for national implementation of the methodology.

  10. Computer Self-Efficacy, Competitive Anxiety and Flow State: Escaping from Firing Online Game

    ERIC Educational Resources Information Center

    Hong, Jon-Chao; Pei-Yu, Chiu; Shih, Hsiao-Feng; Lin, Pei-Shin; Hong, Jon-Chao

    2012-01-01

    Flow state in game playing affected by computer self-efficacy and game competitive anxiety was studied. In order to examine the effect of those constructs with high competition, this study select "Escaping from firing online game" which require college students to escape from fire and rescue people and eliminate the fire damage along the way of…

  11. Application of a Mesoscale Atmospheric Coupled Fire Model BRAMS-FIRE to Alentejo Woodland Fire and Comparison of Performance with the Fire Model WRF-Sfire.

    NASA Astrophysics Data System (ADS)

    Freitas, S. R.; Menezes, I. C.; Stockler, R.; Mello, R.; Ribeiro, N. A.; Corte-Real, J. A. M.; Surový, P.

    2014-12-01

    Models of fuel with the identification of vegetation patterns of Montado ecosystem in Portugal was incorporated in the mesoscale Brazilian Atmospheric Modeling System (BRAMS) and coupled with a spread woodland fire model. The BRAMS-FIRE is a new system developed by the "Centro de Previsão de Tempo e Estudos Climáticos" (CPTEC/INPE, Brazil) and the "Instituto de Ciências Agrárias e Ambientais Mediterrâneas" (ICAAM, Portugal). The fire model used in this effort was originally, developed by Mandel et al. (2013) and further incorporated in the Weather Research and Forecast model (WRF). Two grids of high spatial resolution were configured with surface input data and fuel models integrated for simulations using both models BRAMS-FIRE and WRF-SFIRE. One grid was placed in the plain land near Beja and the other one in the hills of Ossa to evaluate different types of fire propagation and calibrate BRAMS-FIRE. The objective is simulating the effects of atmospheric circulation in local scale, namely the movements of the heat front and energy release associated to it, obtained by this two models in an episode of woodland fire which took place in Alentejo area in the last decade, for application to planning and evaluations of agro woodland fire risks. We aim to model the behavior of forest fires through a set of equations whose solutions provide quantitative values of one or more variables related to the propagation of fire, described by semi-empirical expressions that are complemented by experimental data allow to obtain the main variables related advancing the perimeter of the fire, as the propagation speed, the intensity of the fire front and fuel consumption and its interaction with atmospheric dynamic system. References Mandel, J., J. D. Beezley, G. Kelman, A. K. Kochanski, V. Y. Kondratenko, B. H. Lynn, and M. Vejmelka, 2013. New features in WRF-SFIRE and the wildfire forecasting and danger system in Israel. Natural Hazards and Earth System Sciences, submitted

  12. CAFE: A Computer Tool for Accurate Simulation of the Regulatory Pool Fire Environment for Type B Packages

    SciTech Connect

    Gritzo, L.A.; Koski, J.A.; Suo-Anttila, A.J.

    1999-03-16

    The Container Analysis Fire Environment computer code (CAFE) is intended to provide Type B package designers with an enhanced engulfing fire boundary condition when combined with the PATRAN/P-Thermal commercial code. Historically an engulfing fire boundary condition has been modeled as {sigma}T{sup 4} where {sigma} is the Stefan-Boltzman constant, and T is the fire temperature. The CAFE code includes the necessary chemistry, thermal radiation, and fluid mechanics to model an engulfing fire. Effects included are the local cooling of gases that form a protective boundary layer that reduces the incoming radiant heat flux to values lower than expected from a simple {sigma}T{sup 4} model. In addition, the effect of object shape on mixing that may increase the local fire temperature is included. Both high and low temperature regions that depend upon the local availability of oxygen are also calculated. Thus the competing effects that can both increase and decrease the local values of radiant heat flux are included in a reamer that is not predictable a-priori. The CAFE package consists of a group of computer subroutines that can be linked to workstation-based thermal analysis codes in order to predict package performance during regulatory and other accident fire scenarios.

  13. Mathematical modeling of forest fire initiation in three dimensional setting

    Treesearch

    Valeriy Perminov

    2007-01-01

    In this study, the assignment and theoretical investigations of the problems of forest fire initiation were carried out, including development of a mathematical model for description of heat and mass transfer processes in overterrestrial layer of atmosphere at crown forest fire initiation, taking into account their mutual influence. Mathematical model of forest fire...

  14. Chapter 2: Fire and Fuels Extension: Model description

    Treesearch

    Sarah J. Beukema; Elizabeth D. Reinhardt; Julee A. Greenough; Donald C. E. Robinson; Werner A. Kurz

    2003-01-01

    The Fire and Fuels Extension to the Forest Vegetation Simulator is a model that simulates fuel dynamics and potential fire behavior over time, in the context of stand development and management. Existing models are used to represent forest stand development (the Forest Vegetation Simulator, Wykoff and others 1982), fire behavior (Rothermel 1972, Van Wagner 1977, and...

  15. A simple physical model for forest fire spread

    Treesearch

    E. Koo; P. Pagni; J. Woycheese; S. Stephens; D. Weise; J. Huff

    2005-01-01

    Based on energy conservation and detailed heat transfer mechanisms, a simple physical model for fire spread is presented for the limit of one-dimensional steady-state contiguous spread of a line fire in a thermally-thin uniform porous fuel bed. The solution for the fire spread rate is found as an eigenvalue from this model with appropriate boundary conditions through a...

  16. A landscape-scale wildland fire study using coupled weather-wildland fire model and airborne remote sensing

    Treesearch

    J.L. Coen; Philip Riggan

    2011-01-01

    We examine the Esperanza fire, a Santa Ana-driven wildland fire that occurred in complex terrain in spatially heterogeneous chaparral fuels, using airborne remote sensing imagery from the FireMapper thermal-imaging radiometer and a coupled weather-wildland fire model. The radiometer data maps fire intensity and is used to evaluate the error in the extent of the...

  17. The status and challenge of global fire modelling

    DOE PAGES

    Hantson, Stijn; Arneth, Almut; Harrison, Sandy P.; ...

    2016-06-09

    Biomass burning impacts vegetation dynamics, biogeochemical cycling, atmospheric chemistry, and climate, with sometimes deleterious socio-economic impacts. Under future climate projections it is often expected that the risk of wildfires will increase. Our ability to predict the magnitude and geographic pattern of future fire impacts rests on our ability to model fire regimes, using either well-founded empirical relationships or process-based models with good predictive skill. While a large variety of models exist today, it is still unclear which type of model or degree of complexity is required to model fire adequately at regional to global scales. This is the central questionmore » underpinning the creation of the Fire Model Intercomparison Project (FireMIP), an international initiative to compare and evaluate existing global fire models against benchmark data sets for present-day and historical conditions. In this paper we review how fires have been represented in fire-enabled dynamic global vegetation models (DGVMs) and give an overview of the current state of the art in fire-regime modelling. In conclusion, we indicate which challenges still remain in global fire modelling and stress the need for a comprehensive model evaluation and outline what lessons may be learned from FireMIP.« less

  18. The status and challenge of global fire modelling

    SciTech Connect

    Hantson, Stijn; Arneth, Almut; Harrison, Sandy P.; Kelley, Douglas I.; Prentice, I. Colin; Rabin, Sam S.; Archibald, Sally; Mouillot, Florent; Arnold, Steve R.; Artaxo, Paulo; Bachelet, Dominique; Ciais, Philippe; Forrest, Matthew; Friedlingstein, Pierre; Hickler, Thomas; Kaplan, Jed O.; Kloster, Silvia; Knorr, Wolfgang; Lasslop, Gitta; Li, Fang; Mangeon, Stephane; Melton, Joe R.; Meyn, Andrea; Sitch, Stephen; Spessa, Allan; van der Werf, Guido R.; Voulgarakis, Apostolos; Yue, Chao

    2016-06-09

    Biomass burning impacts vegetation dynamics, biogeochemical cycling, atmospheric chemistry, and climate, with sometimes deleterious socio-economic impacts. Under future climate projections it is often expected that the risk of wildfires will increase. Our ability to predict the magnitude and geographic pattern of future fire impacts rests on our ability to model fire regimes, using either well-founded empirical relationships or process-based models with good predictive skill. While a large variety of models exist today, it is still unclear which type of model or degree of complexity is required to model fire adequately at regional to global scales. This is the central question underpinning the creation of the Fire Model Intercomparison Project (FireMIP), an international initiative to compare and evaluate existing global fire models against benchmark data sets for present-day and historical conditions. In this paper we review how fires have been represented in fire-enabled dynamic global vegetation models (DGVMs) and give an overview of the current state of the art in fire-regime modelling. In conclusion, we indicate which challenges still remain in global fire modelling and stress the need for a comprehensive model evaluation and outline what lessons may be learned from FireMIP.

  19. The status and challenge of global fire modelling

    NASA Astrophysics Data System (ADS)

    Hantson, Stijn; Arneth, Almut; Harrison, Sandy P.; Kelley, Douglas I.; Prentice, I. Colin; Rabin, Sam S.; Archibald, Sally; Mouillot, Florent; Arnold, Steve R.; Artaxo, Paulo; Bachelet, Dominique; Ciais, Philippe; Forrest, Matthew; Friedlingstein, Pierre; Hickler, Thomas; Kaplan, Jed O.; Kloster, Silvia; Knorr, Wolfgang; Lasslop, Gitta; Li, Fang; Mangeon, Stephane; Melton, Joe R.; Meyn, Andrea; Sitch, Stephen; Spessa, Allan; van der Werf, Guido R.; Voulgarakis, Apostolos; Yue, Chao

    2016-06-01

    Biomass burning impacts vegetation dynamics, biogeochemical cycling, atmospheric chemistry, and climate, with sometimes deleterious socio-economic impacts. Under future climate projections it is often expected that the risk of wildfires will increase. Our ability to predict the magnitude and geographic pattern of future fire impacts rests on our ability to model fire regimes, using either well-founded empirical relationships or process-based models with good predictive skill. While a large variety of models exist today, it is still unclear which type of model or degree of complexity is required to model fire adequately at regional to global scales. This is the central question underpinning the creation of the Fire Model Intercomparison Project (FireMIP), an international initiative to compare and evaluate existing global fire models against benchmark data sets for present-day and historical conditions. In this paper we review how fires have been represented in fire-enabled dynamic global vegetation models (DGVMs) and give an overview of the current state of the art in fire-regime modelling. We indicate which challenges still remain in global fire modelling and stress the need for a comprehensive model evaluation and outline what lessons may be learned from FireMIP.

  20. Modelling Variable Fire Severity in Boreal Forests: Effects of Fire Intensity and Stand Structure

    PubMed Central

    Miquelajauregui, Yosune; Cumming, Steven G.; Gauthier, Sylvie

    2016-01-01

    It is becoming clear that fires in boreal forests are not uniformly stand-replacing. On the contrary, marked variation in fire severity, measured as tree mortality, has been found both within and among individual fires. It is important to understand the conditions under which this variation can arise. We integrated forest sample plot data, tree allometries and historical forest fire records within a diameter class-structured model of 1.0 ha patches of mono-specific black spruce and jack pine stands in northern Québec, Canada. The model accounts for crown fire initiation and vertical spread into the canopy. It uses empirical relations between fire intensity, scorch height, the percent of crown scorched and tree mortality to simulate fire severity, specifically the percent reduction in patch basal area due to fire-caused mortality. A random forest and a regression tree analysis of a large random sample of simulated fires were used to test for an effect of fireline intensity, stand structure, species composition and pyrogeographic regions on resultant severity. Severity increased with intensity and was lower for jack pine stands. The proportion of simulated fires that burned at high severity (e.g. >75% reduction in patch basal area) was 0.80 for black spruce and 0.11 for jack pine. We identified thresholds in intensity below which there was a marked sensitivity of simulated fire severity to stand structure, and to interactions between intensity and structure. We found no evidence for a residual effect of pyrogeographic region on simulated severity, after the effects of stand structure and species composition were accounted for. The model presented here was able to produce variation in fire severity under a range of fire intensity conditions. This suggests that variation in stand structure is one of the factors causing the observed variation in boreal fire severity. PMID:26919456

  1. Modelling Variable Fire Severity in Boreal Forests: Effects of Fire Intensity and Stand Structure.

    PubMed

    Miquelajauregui, Yosune; Cumming, Steven G; Gauthier, Sylvie

    2016-01-01

    It is becoming clear that fires in boreal forests are not uniformly stand-replacing. On the contrary, marked variation in fire severity, measured as tree mortality, has been found both within and among individual fires. It is important to understand the conditions under which this variation can arise. We integrated forest sample plot data, tree allometries and historical forest fire records within a diameter class-structured model of 1.0 ha patches of mono-specific black spruce and jack pine stands in northern Québec, Canada. The model accounts for crown fire initiation and vertical spread into the canopy. It uses empirical relations between fire intensity, scorch height, the percent of crown scorched and tree mortality to simulate fire severity, specifically the percent reduction in patch basal area due to fire-caused mortality. A random forest and a regression tree analysis of a large random sample of simulated fires were used to test for an effect of fireline intensity, stand structure, species composition and pyrogeographic regions on resultant severity. Severity increased with intensity and was lower for jack pine stands. The proportion of simulated fires that burned at high severity (e.g. >75% reduction in patch basal area) was 0.80 for black spruce and 0.11 for jack pine. We identified thresholds in intensity below which there was a marked sensitivity of simulated fire severity to stand structure, and to interactions between intensity and structure. We found no evidence for a residual effect of pyrogeographic region on simulated severity, after the effects of stand structure and species composition were accounted for. The model presented here was able to produce variation in fire severity under a range of fire intensity conditions. This suggests that variation in stand structure is one of the factors causing the observed variation in boreal fire severity.

  2. Development of a Fire Risk Model to Identify Areas of Increased Potential for Fire Occurrences.

    PubMed

    Lehna, Carlee; Speller, Amanda; Hanchette, Carol; Fahey, Erin; Coty, Mary-Beth

    2016-01-01

    The purposes of this study were to use geographic information systems to create a cartographic risk model predicting areas of increased potential for fire occurrences and to validate the model. Seven literature-identified risk factors associated with burn injury were older than 65 years, non-white race, below high school education, low socioeconomic status, rented housing, year home built, and home value. Geographic information system methods were used in risk factor model development. Model validation occurred using residential county fire dispatch data and statistical analysis. Areas of high and severe risk were primarily located in the northwestern and central county regions. A strong correlation (r = .66) was found between risk model scores and fire incidence rates. Significant differences in mean fire rates by risk category (F (187,3) = 87.58, P < .0001) were found, with the exception of the low and medium risk categories. Fire incidence rates among census tracts showed positive spatial autocorrelation (Moran's I = 0.542, P < .0001) producing a map showing a significant cluster of high fire incidence in the northwestern region. The risk model has potential to lead to more targeted and effective fire prevention education programs. Such models would allow fire departments to focus limited resources in areas of highest fire risk.

  3. Underground Coal-Fires in Xinjiang, China: Assessment of Fire Dynamics from Surface Measurements and Modeling

    NASA Astrophysics Data System (ADS)

    Wuttke, Manfred W.; Zeng, Qiang; Tanner, David C.; Halisch, Matthias; Cai, Zhong-yong; Wang, Chunli

    2013-04-01

    Spontaneous uncontrolled coal seam fires are a well known phenomenon that causes severe environmental problems and severe impact on natural coal reserves. Coal fires are a worldwide phenomenon, but in particular in Xinjiang, that covers 17.3 % of Chinas area and hosts approx 42 % of its coal resources. The Xinjiang Coalfield Fire Fighting Bureau (XJCFB) has developed technologies and methods to deal with any known fire. Many fires have been extinguished already, but the problem is still there if not even growing. This problem is not only a problem for China due to the loss of valuable energy resources, but it is also a worldwide threat because of the generation of substantial amounts of greenhouse gases. In this contribution we describe the latest results from a new conjoint project between China and Germany where on the basis of field investigations and laboratory measurements realistic dynamical models of fire-zones are constructed to increase the understanding of particular coal-fires, to interpret the surface signatures of the coal-fire in terms of location and propagation and to estimate the output of hazardous exhaust products to evaluate the economic benefit of fire extinction. For two exemplary fire-locations, coarse digital terrain models have been produced. These models serve as basis for a detailed surface exploration by terrestrial laser scanning which shall deliver a detailed fracture inventory. Samples of rock and coal have been taken in the field and are characterized in LIAG's petrophysical laboratory in terms of transport properties. All these data serve as input for our detailed numerical fire models. Repeated measurements of the surface changes together with thermal images reveal the dynamics of fire propagation. The numerical models are calibrated by such data and can later be used to quantify the emissions from such a fire zone.

  4. Fire frequency in the Interior Columbia River Basin: Building regional models from fire history data

    USGS Publications Warehouse

    McKenzie, D.; Peterson, D.L.; Agee, James K.

    2000-01-01

    Fire frequency affects vegetation composition and successional pathways; thus it is essential to understand fire regimes in order to manage natural resources at broad spatial scales. Fire history data are lacking for many regions for which fire management decisions are being made, so models are needed to estimate past fire frequency where local data are not yet available. We developed multiple regression models and tree-based (classification and regression tree, or CART) models to predict fire return intervals across the interior Columbia River basin at 1-km resolution, using georeferenced fire history, potential vegetation, cover type, and precipitation databases. The models combined semiqualitative methods and rigorous statistics. The fire history data are of uneven quality; some estimates are based on only one tree, and many are not cross-dated. Therefore, we weighted the models based on data quality and performed a sensitivity analysis of the effects on the models of estimation errors that are due to lack of cross-dating. The regression models predict fire return intervals from 1 to 375 yr for forested areas, whereas the tree-based models predict a range of 8 to 150 yr. Both types of models predict latitudinal and elevational gradients of increasing fire return intervals. Examination of regional-scale output suggests that, although the tree-based models explain more of the variation in the original data, the regression models are less likely to produce extrapolation errors. Thus, the models serve complementary purposes in elucidating the relationships among fire frequency, the predictor variables, and spatial scale. The models can provide local managers with quantitative information and provide data to initialize coarse-scale fire-effects models, although predictions for individual sites should be treated with caution because of the varying quality and uneven spatial coverage of the fire history database. The models also demonstrate the integration of

  5. Comparing modelled fire dynamics with charcoal records for the Holocene

    NASA Astrophysics Data System (ADS)

    Brücher, Tim; Brovkin, Victor; Kloster, Silvia; Marlon, Jennifer; Power, Mitch

    2014-05-01

    An Earth System model of intermediate complexity, CLIMBER-2, and land surface model JSBACH that includes dynamic vegetation, carbon cycle, and fire regime are used for simulation of natural fire dynamics through the last 8,000 years. To compare the fire model results with the charcoal reconstructions, several output variables of the fire model (burned area, carbon emissions) and several approaches of model output processing are tested. The z-scores out of charcoal dataset have been calculated for the period 8,000 to 200 BP to exclude a period of strong anthropogenic forcing during the last two centuries. The model analysis points mainly to an increasing fire activity during the Holocene for most of the investigated areas, which is in good correspondence to reconstructed fire trends out of charcoal data for most of the tested regions, while for few regions such as Europe the simulated trend and the reconstructed trends are different. The difference between the modeled and reconstructed fire activity could be due to absence of the anthropogenic forcing in the model simulations, but also due to limitations of model assumptions for modeling fire dynamics. For the model trends, the usage of averaging or z-score processing of model output resulted in similar directions of trend. Therefore, the approach of fire model output processing does not effect results of the model-data comparison. Global fire modeling is still in its infancy; improving our representations of fire through validation exercises such as what we present here is thus essential before testing hypotheses about the effects of extreme climate changes on fire behavior and potential feedbacks that result from those changes. Brücher, T., Brovkin, V., Kloster, S., Marlon, J. R., and Power, M. J.: Comparing modelled fire dynamics with charcoal records for the Holocene, Clim. Past Discuss., 9, 6429-6458, doi:10.5194/cpd-9-6429-2013, 2013.

  6. Fuel models and fire potential from satellite and surface observations

    USGS Publications Warehouse

    Burgan, R.E.; Klaver, R.W.; Klarer, J.M.

    1998-01-01

    A national 1-km resolution fire danger fuel model map was derived through use of previously mapped land cover classes and ecoregions, and extensive ground sample data, then refined through review by fire managers familiar with various portions of the U.S. The fuel model map will be used in the next generation fire danger rating system for the U.S., but it also made possible immediate development of a satellite and ground based fire potential index map. The inputs and algorithm of the fire potential index are presented, along with a case study of the correlation between the fire potential index and fire occurrence in California and Nevada. Application of the fire potential index in the Mediterranean ecosystems of Spain, Chile, and Mexico will be tested.

  7. Reformulation of Rothermel's wildland fire behaviour model for heterogeneous fuelbeds.

    Treesearch

    David V. Sandberg; Cynthia L. Riccardi; Mark D. Schaaf

    2007-01-01

    Abstract: The Fuel Characteristic Classification System (FCCS) includes equations that calculate energy release and one-dimensional spread rate in quasi-steady-state fires in heterogeneous but spatially uniform wildland fuelbeds, using a reformulation of the widely used Rothermel fire spread model. This reformulation provides an automated means to predict fire behavior...

  8. Wildland fire probabilities estimated from weather model-deduced monthly mean fire danger indices

    Treesearch

    Haiganoush K. Preisler; Shyh-Chin Chen; Francis Fujioka; John W. Benoit; Anthony L. Westerling

    2008-01-01

    The National Fire Danger Rating System indices deduced from a regional simulation weather model were used to estimate probabilities and numbers of large fire events on monthly and 1-degree grid scales. The weather model simulations and forecasts are ongoing experimental products from the Experimental Climate Prediction Center at the Scripps Institution of Oceanography...

  9. Thermal weapon sights with integrated fire control computers: algorithms and experiences

    NASA Astrophysics Data System (ADS)

    Rothe, Hendrik; Graswald, Markus; Breiter, Rainer

    2008-04-01

    The HuntIR long range thermal weapon sight of AIM is deployed in various out of area missions since 2004 as a part of the German Future Infantryman system (IdZ). In 2007 AIM fielded RangIR as upgrade with integrated laser Range finder (LRF), digital magnetic compass (DMC) and fire control unit (FCU). RangIR fills the capability gaps of day/night fire control for grenade machine guns (GMG) and the enhanced system of the IdZ. Due to proven expertise and proprietary methods in fire control, fast access to military trials for optimisation loops and similar hardware platforms, AIM and the University of the Federal Armed Forces Hamburg (HSU) decided to team for the development of suitable fire control algorithms. The pronounced ballistic trajectory of the 40mm GMG requires most accurate FCU-solutions specifically for air burst ammunition (ABM) and is most sensitive to faint effects like levelling or firing up/downhill. This weapon was therefore selected to validate the quality of the FCU hard- and software under relevant military conditions. For exterior ballistics the modified point mass model according to STANAG 4355 is used. The differential equations of motions are solved numerically, the two point boundary value problem is solved iteratively. Computing time varies according to the precision needed and is typical in the range from 0.1 - 0.5 seconds. RangIR provided outstanding hit accuracy including ABM fuze timing in various trials of the German Army and allied partners in 2007 and is now ready for series production. This paper deals mainly with the fundamentals of the fire control algorithms and shows how to implement them in combination with any DSP-equipped thermal weapon sights (TWS) in a variety of light supporting weapon systems.

  10. Modelling Fire Frequency in a Cerrado Savanna Protected Area

    PubMed Central

    Pereira Júnior, Alfredo C.; Oliveira, Sofia L. J.; Pereira, José M. C.; Turkman, Maria Antónia Amaral

    2014-01-01

    Covering almost a quarter of Brazil, the Cerrado is the world’s most biologically rich tropical savanna. Fire is an integral part of the Cerrado but current land use and agricultural practices have been changing fire regimes, with undesirable consequences for the preservation of biodiversity. In this study, fire frequency and fire return intervals were modelled over a 12-year time series (1997–2008) for the Jalapão State Park, a protected area in the north of the Cerrado, based on burned area maps derived from Landsat imagery. Burned areas were classified using object based image analysis. Fire data were modelled with the discrete lognormal model and the estimated parameters were used to calculate fire interval, fire survival and hazard of burning distributions, for seven major land cover types. Over the study period, an area equivalent to four times the size of Jalapão State Park burned and the mean annual area burned was 34%. Median fire intervals were generally short, ranging from three to six years. Shrub savannas had the shortest fire intervals, and dense woodlands the longest. Because fires in the Cerrado are strongly responsive to fuel age in the first three to four years following a fire, early dry season patch mosaic burning may be used to reduce the extent of area burned and the severity of fire effects. PMID:25054540

  11. Modelling fire frequency in a Cerrado savanna protected area.

    PubMed

    Pereira Júnior, Alfredo C; Oliveira, Sofia L J; Pereira, José M C; Turkman, Maria Antónia Amaral

    2014-01-01

    Covering almost a quarter of Brazil, the Cerrado is the world's most biologically rich tropical savanna. Fire is an integral part of the Cerrado but current land use and agricultural practices have been changing fire regimes, with undesirable consequences for the preservation of biodiversity. In this study, fire frequency and fire return intervals were modelled over a 12-year time series (1997-2008) for the Jalapão State Park, a protected area in the north of the Cerrado, based on burned area maps derived from Landsat imagery. Burned areas were classified using object based image analysis. Fire data were modelled with the discrete lognormal model and the estimated parameters were used to calculate fire interval, fire survival and hazard of burning distributions, for seven major land cover types. Over the study period, an area equivalent to four times the size of Jalapão State Park burned and the mean annual area burned was 34%. Median fire intervals were generally short, ranging from three to six years. Shrub savannas had the shortest fire intervals, and dense woodlands the longest. Because fires in the Cerrado are strongly responsive to fuel age in the first three to four years following a fire, early dry season patch mosaic burning may be used to reduce the extent of area burned and the severity of fire effects.

  12. Forest fire weather and computed fire occurrence in western Oregon and western Washington in 1960.

    Treesearch

    Owen P. Cramer

    1960-01-01

    Fire season severity in 1960 was about average in western Washington but was very high in western Oregon. Severity of the entire season in both States was slightly greater than in 1959. Although spring was less severe, both summer and fall were slightly more severe than comparable parts of the previous fire season. Spring fire danger in western Washington was as low as...

  13. Modeling fire occurrence as a function of landscape

    NASA Astrophysics Data System (ADS)

    Loboda, T. V.; Carroll, M.; DiMiceli, C.

    2011-12-01

    Wildland fire is a prominent component of ecosystem functioning worldwide. Nearly all ecosystems experience the impact of naturally occurring or anthropogenically driven fire. Here, we present a spatially explicit and regionally parameterized Fire Occurrence Model (FOM) aimed at developing fire occurrence estimates at landscape and regional scales. The model provides spatially explicit scenarios of fire occurrence based on the available records from fire management agencies, satellite observations, and auxiliary geospatial data sets. Fire occurrence is modeled as a function of the risk of ignition, potential fire behavior, and fire weather using internal regression tree-driven algorithms and empirically established, regionally derived relationships between fire occurrence, fire behavior, and fire weather. The FOM presents a flexible modeling structure with a set of internal globally available default geospatial independent and dependent variables. However, the flexible modeling environment adapts to ingest a variable number, resolution, and content of inputs provided by the user to supplement or replace the default parameters to improve the model's predictive capability. A Southern California FOM instance (SC FOM) was developed using satellite assessments of fire activity from a suite of Landsat and Moderate Resolution Imaging Spectroradiometer (MODIS) satellite data, Monitoring Trends in Burn Severity fire perimeters, and auxiliary geospatial information including land use and ownership, utilities, transportation routes, and the Remote Automated Weather Station data records. The model was parameterized based on satellite data acquired between 2001 and 2009 and fire management fire perimeters available prior to 2009. SC FOM predictive capabilities were assessed using observed fire occurrence available from the MODIS active fire product during 2010. The results show that SC FOM provides a realistic estimate of fire occurrence at the landscape level: the fraction of

  14. Large urban fire environment. Trends and model city predictions

    SciTech Connect

    Larson, D.A.; Small, R.D.

    1982-01-01

    The urban fire environment that would result from a megaton-yield nuclear weapon burst is considered. The dependence of temperatures and velocities on fire size, burning intensity, turbulence, and radiation is explored, and specific calculations for three model urban areas are presented. In all cases, high velocity fire winds are predicted. The model-city results show the influence of building density and urban sprawl on the fire environment. Additional calculations consider large-area fires with the burning intensity reduced in a blast-damaged urban center.

  15. Calculation of precise firing statistics in a neural network model

    NASA Astrophysics Data System (ADS)

    Cho, Myoung Won

    2017-08-01

    A precise prediction of neural firing dynamics is requisite to understand the function of and the learning process in a biological neural network which works depending on exact spike timings. Basically, the prediction of firing statistics is a delicate manybody problem because the firing probability of a neuron at a time is determined by the summation over all effects from past firing states. A neural network model with the Feynman path integral formulation is recently introduced. In this paper, we present several methods to calculate firing statistics in the model. We apply the methods to some cases and compare the theoretical predictions with simulation results.

  16. INFERNO, a simple approach for interactive fires and their emissions within the Met Office Unified Model

    NASA Astrophysics Data System (ADS)

    Mangeon, Stephane; Voulgarakis, Apostolos; Folberth, Gerd

    2015-04-01

    Forest fires remain a crucial element of the Earth system, affecting and affected by the biosphere and the atmosphere. In particular emissions of trace gases (CO2, CO, NOx...) from forest fires can affect radiative forcing as well as atmospheric composition, similarly aerosols such as Black Carbon (also a strong sunlight absorber) and Organic Carbon emitted by fires can participate in cloud droplet nucleation, contributing to the aerosol indirect effect. Global estimates of fire emissions have greatly improved over the last decade, mainly through the developments in satellite observations. However, such estimates remain constrained to the recent satellite observational period; to study fires under past and future climates one has to resort to models. We will present the INteractive Fire and Emission algoRithm for Natural envirOnments (INFERNO) scheme for the Met Office's Unified Model, which builds on previous work for the GISS climate model. We start from simulated fire counts using proxies for flammability (meteorology and vegetation), ignitions and fire suppression. We then extend this parameterisation to predict burnt area, burnt biomass and subsequent emissions. This climate-sensitive parameterisation utilises temperature, relative humidity, precipitation and vegetation modelling (biomass and leaf area index) to model flammability. Ignitions depend on population density and lightning strikes. Of all these variables, only population density needs to be prescribed, hence INFERNO can be run interactively within a coupled earth system model. Our approach is also distinct owing to its simplicity and is computationally inexpensive, a necessary characteristic as it is aimed to run interactively over climatological timescales. The performance of this scheme is assessed against the Global Fire Emissions Database (GFED); early analysis shows this new approach effectively captures the spatial and inter-annual variability of burnt area and fire emissions of CO2 and CO

  17. 76 FR 46330 - NUREG-1934, Nuclear Power Plant Fire Modeling Application Guide (NPP FIRE MAG); Second Draft...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-02

    ... COMMISSION NUREG-1934, Nuclear Power Plant Fire Modeling Application Guide (NPP FIRE MAG); Second Draft... for public comment a document entitled, NUREG-1934 (EPRI 1023259), ``Nuclear Power Plant Fire Modeling Application Guide (NPP FIRE MAG), Second Draft Report for Comment.'' DATES: Please submit comments by...

  18. Comparing effects of fire modeling methods on simulated fire patterns and succession: a case study in the Missouri Ozarks

    Treesearch

    Jian Yang; Hong S. He; Brian R. Sturtevant; Brian R. Miranda; Eric J. Gustafson

    2008-01-01

    We compared four fire spread simulation methods (completely random, dynamic percolation. size-based minimum travel time algorithm. and duration-based minimum travel time algorithm) and two fire occurrence simulation methods (Poisson fire frequency model and hierarchical fire frequency model) using a two-way factorial design. We examined these treatment effects on...

  19. Fuel consumption and fire emissions estimates using Fire Radiative Power, burned area and statistical modelling on the fire event scale

    NASA Astrophysics Data System (ADS)

    Ruecker, Gernot; Leimbach, David; Guenther, Felix; Barradas, Carol; Hoffmann, Anja

    2016-04-01

    Fire Radiative Power (FRP) retrieved by infrared sensors, such as flown on several polar orbiting and geostationary satellites, has been shown to be proportional to fuel consumption rates in vegetation fires, and hence the total radiative energy released by a fire (Fire Radiative Energy, FRE) is proportional to the total amount of biomass burned. However, due to the sparse temporal coverage of polar orbiting and the coarse spatial resolution of geostationary sensors, it is difficult to estimate fuel consumption for single fire events. Here we explore an approach for estimating FRE through temporal integration of MODIS FRP retrievals over MODIS-derived burned areas. Temporal integration is aided by statistical modelling to estimate missing observations using a generalized additive model (GAM) and taking advantage of additional information such as land cover and a global dataset of the Canadian Fire Weather Index (FWI), as well as diurnal and annual FRP fluctuation patterns. Based on results from study areas located in savannah regions of Southern and Eastern Africa and Brazil, we compare this method to estimates based on simple temporal integration of FRP retrievals over the fire lifetime, and estimate the potential variability of FRP integration results across a range of fire sizes. We compare FRE-based fuel consumption against a database of field experiments in similar landscapes. Results show that for larger fires, this method yields realistic estimates and is more robust when only a small number of observations is available than the simple temporal integration. Finally, we offer an outlook on the integration of data from other satellites, specifically FireBird, S-NPP VIIRS and Sentinel-3, as well as on using higher resolution burned area data sets derived from Landsat and similar sensors.

  20. Comparing modeled fire dynamics with charcoal records for the Holocene

    NASA Astrophysics Data System (ADS)

    Bruecher, T.; Brovkin, V.; Kloster, S.; Marlon, J. R.; Power, M. J.

    2013-12-01

    An Earth System model of intermediate complexity, CLIMBER-2, and land surface model JSBACH that includes dynamic vegetation, carbon cycle, and fire regime are used for simulation of natural fire dynamics through the last 8,000 years. To compare the fire model results with the charcoal reconstructions, several output variables of the fire model (burned area, carbon emissions) and several approaches of model output processing are tested. The z-scores out of charcoal dataset have been calculated for the period 8,000 to 200 BP to exclude a period of strong anthropogenic forcing during the last two centuries. The model analysis points mainly to an increasing fire activity during the Holocene for most of the investigated areas, which is in good correspondence to reconstructed fire trends out of charcoal data for most of the tested regions, while for few regions such as Europe the simulated trend and the reconstructed trends are different. The difference between the modeled and reconstructed fire activity could be due to absence of the anthropogenic forcing in the model simulations, but also due to limitations of model assumptions for modeling fire dynamics. For the model trends, the usage of averaging or z-score processing of model output resulted in similar directions of trend. Therefore, the approach of fire model output processing does not effect results of the model-data comparison. Global fire modeling is still in its infancy; improving our representations of fire through validation exercises such as what we present here is thus essential before testing hypotheses about the effects of extreme climate changes on fire behavior and potential feedbacks that result from those changes.

  1. Slurry fired heater cold-flow modelling

    SciTech Connect

    Moujaes, S.F.

    1983-07-01

    This report summarizes the experimental and theoretical work leading to the scale-up of the SRC-I Demonstration Plant slurry fired heater. The scale-up involved a theoretical model using empirical relations in the derivation, and employed variables such as flow conditions, liquid viscosity, and slug frequency. Such variables have been shown to affect the heat transfer characteristics ofthe system. The model assumes that, if all other variables remain constant, the heat transfer coefficient can be scaled up proportional to D/sup -2/3/ (D = inside diameter of the fired heater tube). All flow conditions, liquid viscosities, and pipe inclinations relevant to the demonstration plant have indicated a slug flow regime in the slurry fired heater. The annular and stratified flow regimes should be avoided to minimize the potential for excessive pipe erosion and to decrease temperature gradients along the pipe cross section leading to coking and thermal stresses, respectively. Cold-flow studies in 3- and 6.75-in.-inside-diameter (ID) pipes were conducted to determine the effect of scale-up on flow regime, slug frequency, and slug dimensions. The developed model assumes that conduction heat transfer occurs through the liquid film surrounding the gas slug and laminar convective heat transfer to the liquid slug. A weighted average of these two heat transfer mechanisms gives a value for the average pipe heat transfer coefficient. The cold-flow work showed a decrease in the observed slug frequency between the 3- and 6.75-ID pipes. Data on the ratio of gas to liquid slug length in the 6.75-in. pipe are not yet complete, but are expected to yield generally lower values than those obtained in the 3-in. pipe; this will probably affect the scale-up to demonstration plant conditions. 5 references, 15 figures, 7 tables.

  2. A new firing paradigm for integrate and fire stochastic neuronal models.

    PubMed

    Sirovich, Roberta; Testa, Luisa

    2016-06-01

    A new definition of firing time is given in the framework of Integrate and Fire neuronal models. The classical absorption condition at the threshold is relaxed and the firing time is defined as the first time the membrane potential process lies above a fixed depolarisation level for a sufficiently long time. The mathematical properties of the new firing time are investigated both for the Perfect Integrator and the Leaky Integrator. In the latter case, a simulation study is presented to complete the analysis where analytical results are not yet achieved.

  3. Evaluation of a post-fire tree mortality model for western US conifers

    Treesearch

    Sharon M. Hood; Charles W McHugh; Kevin C. Ryan; Elizabeth Reinhardt; Sheri L. Smith

    2007-01-01

    Accurately predicting fire-caused mortality is essential to developing prescribed fire burn plans and post-fire salvage marking guidelines. The mortality model included in the commonly used USA fire behaviour and effects models, the First Order Fire Effects Model (FOFEM), BehavePlus, and the Fire and Fuels Extension to the Forest Vegetation Simulator (FFE-FVS), has not...

  4. Current status and future needs of the BehavePlus Fire Modeling System

    Treesearch

    Patricia L. Andrews

    2014-01-01

    The BehavePlus Fire Modeling System is among the most widely used systems for wildland fire prediction. It is designed for use in a range of tasks including wildfire behaviour prediction, prescribed fire planning, fire investigation, fuel hazard assessment, fire model understanding, communication and research. BehavePlus is based on mathematical models for fire...

  5. A second-order impact model for forest fire regimes.

    PubMed

    Maggi, Stefano; Rinaldi, Sergio

    2006-09-01

    We present a very simple "impact" model for the description of forest fires and show that it can mimic the known characteristics of wild fire regimes in savannas, boreal forests, and Mediterranean forests. Moreover, the distribution of burned biomasses in model generated fires resemble those of burned areas in numerous large forests around the world. The model has also the merits of being the first second-order model for forest fires and the first example of the use of impact models in the study of ecosystems.

  6. Comparison of the KAMELEON fire model to large-scale open pool fire data

    SciTech Connect

    Nicolette, V.F.; Gritzo, L.A.; Holen, J.; Magnussen, B.F.

    1994-06-01

    A comparison of the KAMELEON Fire model to large-scale open pool fire experimental data is presented. The model was used to calculate large-scale JP-4 pool fires with and without wind, and with and without large objects in the fire. The effect of wind and large objects on the fire environment is clearly seen. For the pool fire calculations without any object in the fire, excellent agreement is seen in the location of the oxygen-starved region near the pool center. Calculated flame temperatures are about 200--300 K higher than measured. This results in higher heat fluxes back to the fuel pool and higher fuel evaporation rates (by a factor of 2). Fuel concentrations at lower elevations and peak soot concentrations are in good agreement with data. For pool fire calculations with objects, similar trends in the fire environment are observed. Excellent agreement is seen in the distribution of the heat flux around a cylindrical calorimeter in a rectangular pool with wind effects. The magnitude of the calculated heat flux to the object is high by a factor of 2 relative to the test data, due to the higher temperatures calculated. For the case of a large flat plate adjacent to a circular pool, excellent qualitative agreement is seen in the predicted and measured flame shapes as a function of wind.

  7. Fire!

    ERIC Educational Resources Information Center

    Jones, Rebecca

    1996-01-01

    The number of school fires is up nationwide. This article describes unsafe school conditions, problems with new fire codes, and the factors that contribute to school fires. Installation of sprinkler systems is recommended. A fire-safety checklist is included. (LMI)

  8. Computational Modeling of Tires

    NASA Technical Reports Server (NTRS)

    Noor, Ahmed K. (Compiler); Tanner, John A. (Compiler)

    1995-01-01

    This document contains presentations and discussions from the joint UVA/NASA Workshop on Computational Modeling of Tires. The workshop attendees represented NASA, the Army and Air force, tire companies, commercial software developers, and academia. The workshop objectives were to assess the state of technology in the computational modeling of tires and to provide guidelines for future research.

  9. Integrating fire behavior models and geospatial analysis for wildland fire risk assessment and fuel management planning

    Treesearch

    Alan A. Ager; Nicole M. Vaillant; Mark A. Finney

    2011-01-01

    Wildland fire risk assessment and fuel management planning on federal lands in the US are complex problems that require state-of-the-art fire behavior modeling and intensive geospatial analyses. Fuel management is a particularly complicated process where the benefits and potential impacts of fuel treatments must be demonstrated in the context of land management goals...

  10. Integrated air-pollution control for coal-fired utility boilers: a computer model approach for design and cost-estimating

    SciTech Connect

    Baker, G.E.; Laseke, B.A.; Ponder, T.C.; Milliken, J.O.

    1985-01-01

    The paper describes the Integrated Air Pollution Control System (IAPCS), a computerized program that can be used to estimate the cost and performance of pre-combustion, in situ, and post-combustion air-pollution-control configurations in pulverized-coal-fired utility boilers of 100 to 1000 MW. Modular program design and flexible parameter files allow the user to alter the design and cost basis of any control technology, optimize the emission/cost output, and identify least-cost control alternatives. Physical and chemical characteristics of the flue gas are calculated by material balance and reported in an emission-reduction summary. The program tracks changes in gas temperature, pressure, and volume; fly ash and alkalinity; gaseous pollutants and components; moisture content; and reagent recycling. Capital and annual cost estimates are presented in standardized format for easy comparison with other estimates. Control technologies include physical coal cleaning, limestone injection multistage burners (LIMB), low-NOx burners or overfire air ports, spray humidification, dry sorbent injection, dry scrubbing, limestone flue-gas desulfurization, electrostatic precipitators, and fabric filters. Integrated combinations of these can be optimized both for existing boilers and for new boilers.

  11. Modeling of a coal-fired natural circulation boiler

    SciTech Connect

    Bhambare, K.S.; Mitra, S.K.; Gaitonde, U.N.

    2007-06-15

    Modeling of a natural circulation boiler for a coal-fired thermal power station is presented here. The boiler system is divided into seven subcomponents, and for each section, models based on conservation of mass, momentum, and energy are formulated. The pressure drop at various sections and the heat transfer coefficients are computed using empirical correlations. Solutions are obtained by using SIMULINK. The model is validated by comparing its steady state and dynamic responses with the actual plant data. Open loop responses of the model to the step changes in the operating parameters, such as pressure, temperature, steam flow, feed water flow, are also analyzed. The present model can be used for the development and design of effective boiler control systems.

  12. FireProt: Energy- and Evolution-Based Computational Design of Thermostable Multiple-Point Mutants

    PubMed Central

    Sebestova, Eva; Bendl, Jaroslav; Khare, Sagar; Chaloupkova, Radka; Prokop, Zbynek; Brezovsky, Jan; Baker, David; Damborsky, Jiri

    2015-01-01

    There is great interest in increasing proteins’ stability to enhance their utility as biocatalysts, therapeutics, diagnostics and nanomaterials. Directed evolution is a powerful, but experimentally strenuous approach. Computational methods offer attractive alternatives. However, due to the limited reliability of predictions and potentially antagonistic effects of substitutions, only single-point mutations are usually predicted in silico, experimentally verified and then recombined in multiple-point mutants. Thus, substantial screening is still required. Here we present FireProt, a robust computational strategy for predicting highly stable multiple-point mutants that combines energy- and evolution-based approaches with smart filtering to identify additive stabilizing mutations. FireProt’s reliability and applicability was demonstrated by validating its predictions against 656 mutations from the ProTherm database. We demonstrate that thermostability of the model enzymes haloalkane dehalogenase DhaA and γ-hexachlorocyclohexane dehydrochlorinase LinA can be substantially increased (ΔT m = 24°C and 21°C) by constructing and characterizing only a handful of multiple-point mutants. FireProt can be applied to any protein for which a tertiary structure and homologous sequences are available, and will facilitate the rapid development of robust proteins for biomedical and biotechnological applications. PMID:26529612

  13. Concepts for Future Large Fire Modeling

    Treesearch

    A. P. Dimitrakopoulos; R. E. Martin

    1987-01-01

    A small number of fires escape initial attack suppression efforts and become large, but their effects are significant and disproportionate. In 1983, of 200,000 wildland fires in the United States, only 4,000 exceeded 100 acres. However, these escaped fires accounted for roughly 95 percent of wildfire-related costs and damages (Pyne, 1984). Thus, future research efforts...

  14. FireStem2D — A two-dimensional heat transfer model for simulating tree stem injury in fires

    Treesearch

    Efthalia K. Chatziefstratiou; Gil Bohrer; Anthony S. Bova; Ravishankar Subramanian; Renato P.M. Frasson; Amy Scherzer; Bret W. Butler; Matthew B. Dickinson

    2013-01-01

    FireStem2D, a software tool for predicting tree stem heating and injury in forest fires, is a physically-based, two-dimensional model of stem thermodynamics that results from heating at the bark surface. It builds on an earlier one-dimensional model (FireStem) and provides improved capabilities for predicting fire-induced mortality and injury before a fire occurs by...

  15. Predicting post-fire tree mortality for 12 western US conifers using the First-Order Fire Effects Model (FOFEM)

    Treesearch

    Sharon Hood; Duncan Lutes

    2017-01-01

    Accurate prediction of fire-caused tree mortality is critical for making sound land management decisions such as developing burning prescriptions and post-fire management guidelines. To improve efforts to predict post-fire tree mortality, we developed 3-year post-fire mortality models for 12 Western conifer species - white fir (Abies concolor [Gord. &...

  16. A comparison of geospatially modeled fire behavior and fire management utility of three data sources in the southeastern United States

    Treesearch

    LaWen T. Hollingsworth; Laurie L. Kurth; Bernard R. Parresol; Roger D. Ottmar; Susan J. Prichard

    2012-01-01

    Landscape-scale fire behavior analyses are important to inform decisions on resource management projects that meet land management objectives and protect values from adverse consequences of fire. Deterministic and probabilistic geospatial fire behavior analyses are conducted with various modeling systems including FARSITE, FlamMap, FSPro, and Large Fire Simulation...

  17. Computer Models of Proteins

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Dr. Marc Pusey (seated) and Dr. Craig Kundrot use computers to analyze x-ray maps and generate three-dimensional models of protein structures. With this information, scientists at Marshall Space Flight Center can learn how proteins are made and how they work. The computer screen depicts a proten structure as a ball-and-stick model. Other models depict the actual volume occupied by the atoms, or the ribbon-like structures that are crucial to a protein's function.

  18. Firing patterns in the adaptive exponential integrate-and-fire model.

    PubMed

    Naud, Richard; Marcille, Nicolas; Clopath, Claudia; Gerstner, Wulfram

    2008-11-01

    For simulations of large spiking neuron networks, an accurate, simple and versatile single-neuron modeling framework is required. Here we explore the versatility of a simple two-equation model: the adaptive exponential integrate-and-fire neuron. We show that this model generates multiple firing patterns depending on the choice of parameter values, and present a phase diagram describing the transition from one firing type to another. We give an analytical criterion to distinguish between continuous adaption, initial bursting, regular bursting and two types of tonic spiking. Also, we report that the deterministic model is capable of producing irregular spiking when stimulated with constant current, indicating low-dimensional chaos. Lastly, the simple model is fitted to real experiments of cortical neurons under step current stimulation. The results provide support for the suitability of simple models such as the adaptive exponential integrate-and-fire neuron for large network simulations.

  19. Integrating remote sensing and terrain data in forest fire modeling

    NASA Astrophysics Data System (ADS)

    Medler, Michael Johns

    Forest fire policies are changing. Managers now face conflicting imperatives to re-establish pre-suppression fire regimes, while simultaneously preventing resource destruction. They must, therefore, understand the spatial patterns of fires. Geographers can facilitate this understanding by developing new techniques for mapping fire behavior. This dissertation develops such techniques for mapping recent fires and using these maps to calibrate models of potential fire hazards. In so doing, it features techniques that strive to address the inherent complexity of modeling the combinations of variables found in most ecological systems. Image processing techniques were used to stratify the elements of terrain, slope, elevation, and aspect. These stratification images were used to assure sample placement considered the role of terrain in fire behavior. Examination of multiple stratification images indicated samples were placed representatively across a controlled range of scales. The incorporation of terrain data also improved preliminary fire hazard classification accuracy by 40%, compared with remotely sensed data alone. A Kauth-Thomas transformation (KT) of pre-fire and post-fire Thematic Mapper (TM) remotely sensed data produced brightness, greenness, and wetness images. Image subtraction indicated fire induced change in brightness, greenness, and wetness. Field data guided a fuzzy classification of these change images. Because fuzzy classification can characterize a continuum of a phenomena where discrete classification may produce artificial borders, fuzzy classification was found to offer a range of fire severity information unavailable with discrete classification. These mapped fire patterns were used to calibrate a model of fire hazards for the entire mountain range. Pre-fire TM, and a digital elevation model produced a set of co-registered images. Training statistics were developed from 30 polygons associated with the previously mapped fire severity. Fuzzy

  20. Computational Flame Characterization of New Large Aircraft Immersed in Hydrocarbon Pool Fires

    DTIC Science & Technology

    2013-08-01

    limited scope of the flow field. In addition, the destructive combustion environment results in reduced life expectancy for both fabricated test and DAQ... Tests With a Large Cylindrical Calorimeter on the Leeward Edge of a JP-8 Pool Fire in Cross- Flow ,” Sandia Report SAND2001-1986, July 2001. 34...Computational Model Setup 9 3.3.1 Turbulence 10 3.3.2 Combustion 10 3.3.3 Radiation Heat Transfer 11 3.3.4 Soot Formation 12 3.3.5 Physical Flow Domain

  1. Computational prediction of tube erosion in coal fired power utility boilers

    SciTech Connect

    Lee, B.E.; Fletcher, C.A.J.; Behnia, M.

    1999-10-01

    Erosion of boiler tubes causes serious operational problems in many pulverized coal-fired utility boilers. A new erosion model has been developed in the present study for the prediction of boiler tube erosion. The Lagrangian approach is employed to predict the behavior of the particulate phase. The results of computational prediction of boiler tube erosion and the various parameters causing erosion are discussed in this paper. Comparison of the numerical predictions for a single tube erosion with experimental data shows very good agreement.

  2. Forest fire weather and computed fire occurrence in western Oregon and western Washington.

    Treesearch

    Owen P. Cramer

    1959-01-01

    Severity of the 1959 fire season varied from well below normal in western Washington to a record-setting high in southwestern Oregon. The season was characterized by well-distributed, short rainy periods separated by comparatively short dry spells that frequently included days of high fire danger. July was the only month with markedly above-normal temperatures, and...

  3. The EFFIS forest fire atmospheric emission model: Application to a major fire event in Portugal

    NASA Astrophysics Data System (ADS)

    Monteiro, A.; Corti, P.; San Miguel-Ayanz, J.; Miranda, A. I.; Borrego, C.

    2014-02-01

    Forest fires are a major contributor of gaseous and particulate compounds to the atmosphere, impairing air quality and affecting human health. A new forest fire emissions module was developed and integrated into the European Forest Fire Information System (EFFIS), which systematically compiles, since 2000, series of burnt area statistics mapped from satellite imagery. This new forest fire emission model was built on classical methodologies of fuel-map based emission estimation that were improved, especially on burning efficiency, fuel consumption estimation and emission factors. It makes the best use of EFFIS near-real time and detailed information on forest fires, mainly concerning products with a high temporal resolution, which is needed to simulate smoke dispersion and chemical transformation in the atmosphere.

  4. Fire

    Treesearch

    John R. Jones; Norbert V. DeByle

    1985-01-01

    In some areas, many aspen stands are all the same age, dating from a single great fire or a year of widespread fires (fig. 1). The 1879 fire in the Jackson Hole region of Wyoming (Loope and Gruell 1973) and the 1904 fires in Arizona's White Mountains (Kallander 1969) are examples. Choate (1966) found that almost all aspen stands in New Mexico were even-aged, many...

  5. Modeling fire and other disturbance processes using LANDIS

    Treesearch

    Stephen R. Shifley; Jian Yang; Hong He

    2009-01-01

    LANDIS is a landscape decision support tool that models spatial relationships to help managers and planners examine the large-scale, long-term, cumulative effects of succession, harvesting, wildfire, prescribed fire, insects, and disease. It can operate on forest landscapes from a few thousand to a few million acres in extent. Fire modeling capabilities in LANDIS are...

  6. Integrating models to predict regional haze from wildland fire.

    Treesearch

    D. McKenzie; S.M. O' Neill; N. Larkin; R.A. Norheim

    2006-01-01

    Visibility impairment from regional haze is a significant problem throughout the continental United States. A substantial portion of regional haze is produced by smoke from prescribed and wildland fires. Here we describe the integration of four simulation models, an array of GIS raster layers, and a set of algorithms for fire-danger calculations into a modeling...

  7. Fire Education Resources Information System: FERIS. A Descriptive Model.

    ERIC Educational Resources Information Center

    Rardin, Kevin

    A descriptive model of the Fire Education Resources Information System (FERIS) is examined in this document. Information regarding educational materials relating to fire prevention, protection, and suppression is discussed. A description of the model is presented in two sections. Section 1, Problem Definition, surveys the background and needs for…

  8. Numerical prediction of heat-flux to massive calorimeters engulfed in regulatory fires with the cask analysis fire environment (CAFE) model

    SciTech Connect

    KOSKI,JORMAN A.; SUO-ANTITLA,AHTI; KRAMER,M. ALEX; GREINER,MILES

    2000-05-11

    Recent observations show that the thermal boundary conditions within large-scale fires are significantly affected by the presence of thermally massive objects. These objects cool the soot and gas near their surfaces, and these effects reduce the incoming radiant heat-flux to values lower than the levels expected from simple {sigma}T{sub fire}{sup 4} models. They also affect the flow and temperature fields in the fire far from their surfaces. The Cask Analysis Fire Environment (CAFE) code has been developed at Sandia National Laboratories to provide an enhanced fire boundary condition for the design of radioactive material packages. CAFE is a set of computer subroutines that use computational fluid mechanics methods to predict convective heat transfer and mixing. It also includes models for fuel and oxygen transport, chemical reaction, and participating-media radiation heat transfer. This code uses two-dimensional computational models so that it has reasonably short turnaround times on standard workstations and is well suited for design and risk studies. In this paper, CAFE is coupled with a commercial finite-element program to model a large cylindrical calorimeter fully engulfed in a pool fire. The time-dependent heat-flux to the calorimeter and the calorimeter surface temperature are determined for several locations around the calorimeter circumference. The variation of heat-flux with location is determined for calorimeters with different diameters and wall thickness, and the observed effects discussed.

  9. One thousand years of fires: Integrating proxy and model data

    USGS Publications Warehouse

    Kehrwald, Natalie; Aleman, Julie C.; Coughlan, Michael; Courtney Mustaphi, Colin J.; Githumbi, Esther N.; Magi, Brian I.; Marlon, Jennifer R.; Power, Mitchell J.

    2016-01-01

    The expected increase in fire activity in the upcoming decades has led to a surge in research trying to understand their causes, the factors that may have influenced similar times of fire activity in the past, and the implications of such fire activity in the future. Multiple types of complementary data provide information on the impacts of current fires and the extent of past fires. The wide array of data encompasses different spatial and temporal resolutions (Figure 1) and includes fire proxy information such as charcoal and tree ring fire scars, observational records, satellite products, modern emissions data, fire models within global land cover and vegetation models, and sociodemographic data for modeling past human land use and ignition frequency. Any single data type is more powerful when combined with another source of information. Merging model and proxy data enables analyses of how fire activity modifies vegetation distribution, air and water quality, and proximity to cities; these analyses in turn support land management decisions relating to conservation and development.

  10. Selection of fire spread model for Russian fire behavior prediction system

    Treesearch

    Alexandra V. Volokitina; Kevin C. Ryan; Tatiana M. Sofronova; Mark A. Sofronov

    2010-01-01

    Mathematical modeling of fire behavior prediction is only possible if the models are supplied with an information database that provides spatially explicit input parameters for modeled area. Mathematical models can be of three kinds: 1) physical; 2) empirical; and 3) quasi-empirical (Sullivan, 2009). Physical models (Grishin, 1992) are of academic interest only because...

  11. A computer code to estimate accidental fire and radioactive airborne releases in nuclear fuel cycle facilities: User's manual for FIRIN

    SciTech Connect

    Chan, M.K.; Ballinger, M.Y.; Owczarski, P.C.

    1989-02-01

    This manual describes the technical bases and use of the computer code FIRIN. This code was developed to estimate the source term release of smoke and radioactive particles from potential fires in nuclear fuel cycle facilities. FIRIN is a product of a broader study, Fuel Cycle Accident Analysis, which Pacific Northwest Laboratory conducted for the US Nuclear Regulatory Commission. The technical bases of FIRIN consist of a nonradioactive fire source term model, compartment effects modeling, and radioactive source term models. These three elements interact with each other in the code affecting the course of the fire. This report also serves as a complete FIRIN user's manual. Included are the FIRIN code description with methods/algorithms of calculation and subroutines, code operating instructions with input requirements, and output descriptions. 40 refs., 5 figs., 31 tabs.

  12. Modeling post-fire hydro-geomorphic recovery in the Waldo Canyon Fire

    NASA Astrophysics Data System (ADS)

    Kinoshita, Alicia; Nourbakhshbeidokhti, Samira; Chin, Anne

    2016-04-01

    Wildfire can have significant impacts on watershed hydrology and geomorphology by changing soil properties and removing vegetation, often increasing runoff and soil erosion and deposition, debris flows, and flooding. Watershed systems may take several years or longer to recover. During this time, post-fire channel changes have the potential to alter hydraulics that influence characteristics such as time of concentration and increase time to peak flow, flow capacity, and velocity. Using the case of the 2012 Waldo Canyon Fire in Colorado (USA), this research will leverage field-based surveys and terrestrial Light Detection and Ranging (LiDAR) data to parameterize KINEROS2 (KINematic runoff and EROSion), an event oriented, physically-based watershed runoff and erosion model. We will use the Automated Geospatial Watershed Assessment (AGWA) tool, which is a GIS-based hydrologic modeling tool that uses commonly available GIS data layers to parameterize, execute, and spatially visualize runoff and sediment yield for watersheds impacted by the Waldo Canyon Fire. Specifically, two models are developed, an unburned (Bear Creek) and burned (Williams) watershed. The models will simulate burn severity and treatment conditions. Field data will be used to validate the burned watersheds for pre- and post-fire changes in infiltration, runoff, peak flow, sediment yield, and sediment discharge. Spatial modeling will provide insight into post-fire patterns for varying treatment, burn severity, and climate scenarios. Results will also provide post-fire managers with improved hydro-geomorphic modeling and prediction tools for water resources management and mitigation efforts.

  13. A VARI-Based Relative Greenness from MODIS Data for Computing the Fire Potential Index

    NASA Technical Reports Server (NTRS)

    Schneider, P.; Roberts, D. A.; Kyriakidis, P. C.

    2008-01-01

    The Fire Potential Index (FPI) relies on relative greenness (RG) estimates from remote sensing data. The Normalized Difference Vegetation index (NDVI), derived from NOAA Advanced Very High Resolution Radiometer (AVHRR) imagery is currently used to calculate RG operationally. Here we evaluated an alternate measure of RG using the Visible Atmospheric Resistant Index (VARI) derived from Moderate Resolution Imaging Spectrometer (MODIS) data. VARI was chosen because it has previously been shown to have the strongest relationship with Live Fuel Moisture (LFM) out of a wide selection of MODIS-derived indices in southern California shrublands. To compare MODIS-based NDVI-FPI and VARI-FPI, RG was calculated from a 6-year time series of MODIS composites and validated against in-situ observations of LFM as a surrogate for vegetation greenness. RG from both indices was then compared in terms of its performance for computing the FPI using historical wildfire data. Computed RG values were regressed against ground-sampled LFM at 14 sites within Los Angeles County. The results indicate the VARI-based RG consistently shows a stronger relationship with observed LFM than NDVI-based RG. With an average R2 of 0.727 compared to a value of only 0.622 for NDVI-RG, VARI-RG showed stronger relationships at 13 out of 14 sites. Based on these results, daily FPI maps were computed for the years 2001 through 2005 using both NDVI-RG and VARI-RG. These were then validated against 12,490 fire detections from the MODIS active fire product using logistic regression. Deviance of the logistic regression model was 408.8 for NDVI-FPI and 176.2 for VARI-FPI. The c-index was found to be 0.69 and 0.78, respectively. The results show that VARI-FP outperforms NDVI-FPI in distinguishing between fire and no-fire events for historical wildfire data in southern California for the given time period.

  14. Can fire atlas data improve species distribution model projections?

    PubMed

    Crimmins, Shawn M; Dobrowski, Solomon Z; Mynsberge, Alison R; Safford, Hugh D

    2014-07-01

    Correlative species distribution models (SDMs) are widely used in studies of climate change impacts, yet are often criticized for failing to incorporate disturbance processes that can influence species distributions. Here we use two temporally independent data sets of vascular plant distributions, climate data, and fire atlas data to examine the influence of disturbance history on SDM projection accuracy through time in the mountain ranges of California, USA. We used hierarchical partitioning to examine the influence of fire occurrence on the distribution of 144 vascular plant species and built a suite of SDMs to examine how the inclusion of fire-related predictors (fire occurrence and departure from historical fire return intervals) affects SDM projection accuracy. Fire occurrence provided the least explanatory power among predictor variables for predicting species' distributions, but provided improved explanatory power for species whose regeneration is tied closely to fire. A measure of the departure from historic fire return interval had greater explanatory power for calibrating modern SDMs than fire occurrence. This variable did not improve internal model accuracy for most species, although it did provide marginal improvement to models for species adapted to high-frequency fire regimes. Fire occurrence and fire return interval departure were strongly related to the climatic covariates used in SDM development, suggesting that improvements in model accuracy may not be expected due to limited additional explanatory power. Our results suggest that the inclusion of coarse-scale measures of disturbance in SDMs may not be necessary to predict species distributions under climate change, particularly for disturbance processes that are largely mediated by climate.

  15. Estimating fire behavior with FIRECAST: user's manual

    Treesearch

    Jack D. Cohen

    1986-01-01

    FIRECAST is a computer program that estimates fire behavior in terms of six fire parameters. Required inputs vary depending on the outputs desired by the fire manager. Fuel model options available to users are these: Northern Forest Fire Laboratory (NFFL), National Fire Danger Rating System (NFDRS), and southern California brushland (SCAL). The program has been...

  16. VIEW OF COMPUTER/DATA COLLECTION AREA, SOUTH OF FIRING ROOM NO. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF COMPUTER/DATA COLLECTION AREA, SOUTH OF FIRING ROOM NO. 3, FACING SOUTHEAST - Cape Canaveral Air Force Station, Launch Complex 39, Launch Control Center, LCC Road, East of Kennedy Parkway North, Cape Canaveral, Brevard County, FL

  17. Computer Modeling and Simulation

    SciTech Connect

    Pronskikh, V. S.

    2014-05-09

    Verification and validation of computer codes and models used in simulation are two aspects of the scientific practice of high importance and have recently been discussed by philosophers of science. While verification is predominantly associated with the correctness of the way a model is represented by a computer code or algorithm, validation more often refers to model’s relation to the real world and its intended use. It has been argued that because complex simulations are generally not transparent to a practitioner, the Duhem problem can arise for verification and validation due to their entanglement; such an entanglement makes it impossible to distinguish whether a coding error or model’s general inadequacy to its target should be blamed in the case of the model failure. I argue that in order to disentangle verification and validation, a clear distinction between computer modeling (construction of mathematical computer models of elementary processes) and simulation (construction of models of composite objects and processes by means of numerical experimenting with them) needs to be made. Holding on to that distinction, I propose to relate verification (based on theoretical strategies such as inferences) to modeling and validation, which shares the common epistemology with experimentation, to simulation. To explain reasons of their intermittent entanglement I propose a weberian ideal-typical model of modeling and simulation as roles in practice. I suggest an approach to alleviate the Duhem problem for verification and validation generally applicable in practice and based on differences in epistemic strategies and scopes

  18. The Fire Modeling Intercomparison Project (FireMIP), phase 1: experimental and analytical protocols with detailed model descriptions

    NASA Astrophysics Data System (ADS)

    Rabin, Sam S.; Melton, Joe R.; Lasslop, Gitta; Bachelet, Dominique; Forrest, Matthew; Hantson, Stijn; Kaplan, Jed O.; Li, Fang; Mangeon, Stéphane; Ward, Daniel S.; Yue, Chao; Arora, Vivek K.; Hickler, Thomas; Kloster, Silvia; Knorr, Wolfgang; Nieradzik, Lars; Spessa, Allan; Folberth, Gerd A.; Sheehan, Tim; Voulgarakis, Apostolos; Kelley, Douglas I.; Prentice, I. Colin; Sitch, Stephen; Harrison, Sandy; Arneth, Almut

    2017-03-01

    The important role of fire in regulating vegetation community composition and contributions to emissions of greenhouse gases and aerosols make it a critical component of dynamic global vegetation models and Earth system models. Over 2 decades of development, a wide variety of model structures and mechanisms have been designed and incorporated into global fire models, which have been linked to different vegetation models. However, there has not yet been a systematic examination of how these different strategies contribute to model performance. Here we describe the structure of the first phase of the Fire Model Intercomparison Project (FireMIP), which for the first time seeks to systematically compare a number of models. By combining a standardized set of input data and model experiments with a rigorous comparison of model outputs to each other and to observations, we will improve the understanding of what drives vegetation fire, how it can best be simulated, and what new or improved observational data could allow better constraints on model behavior. In this paper, we introduce the fire models used in the first phase of FireMIP, the simulation protocols applied, and the benchmarking system used to evaluate the models. We have also created supplementary tables that describe, in thorough mathematical detail, the structure of each model.

  19. Computation identifies structural features that govern neuronal firing properties in slowly adapting touch receptors.

    PubMed

    Lesniak, Daine R; Marshall, Kara L; Wellnitz, Scott A; Jenkins, Blair A; Baba, Yoshichika; Rasband, Matthew N; Gerling, Gregory J; Lumpkin, Ellen A

    2014-01-01

    Touch is encoded by cutaneous sensory neurons with diverse morphologies and physiological outputs. How neuronal architecture influences response properties is unknown. To elucidate the origin of firing patterns in branched mechanoreceptors, we combined neuroanatomy, electrophysiology and computation to analyze mouse slowly adapting type I (SAI) afferents. These vertebrate touch receptors, which innervate Merkel cells, encode shape and texture. SAI afferents displayed a high degree of variability in touch-evoked firing and peripheral anatomy. The functional consequence of differences in anatomical architecture was tested by constructing network models representing sequential steps of mechanosensory encoding: skin displacement at touch receptors, mechanotransduction and action-potential initiation. A systematic survey of arbor configurations predicted that the arrangement of mechanotransduction sites at heminodes is a key structural feature that accounts in part for an afferent's firing properties. These findings identify an anatomical correlate and plausible mechanism to explain the driver effect first described by Adrian and Zotterman. DOI: http://dx.doi.org/10.7554/eLife.01488.001.

  20. NEW IMPROVEMENTS TO MFIRE TO ENHANCE FIRE MODELING CAPABILITIES

    PubMed Central

    Zhou, L.; Smith, A.C.; Yuan, L.

    2016-01-01

    NIOSH's mine fire simulation program, MFIRE, is widely accepted as a standard for assessing and predicting the impact of a fire on the mine ventilation system and the spread of fire contaminants in coal and metal/nonmetal mines, which has been used by U.S. and international companies to simulate fires for planning and response purposes. MFIRE is a dynamic, transient-state, mine ventilation network simulation program that performs normal planning calculations. It can also be used to analyze ventilation networks under thermal and mechanical influence such as changes in ventilation parameters, external influences such as changes in temperature, and internal influences such as a fire. The program output can be used to analyze the effects of these influences on the ventilation system. Since its original development by Michigan Technological University for the Bureau of Mines in the 1970s, several updates have been released over the years. In 2012, NIOSH completed a major redesign and restructuring of the program with the release of MFIRE 3.0. MFIRE's outdated FORTRAN programming language was replaced with an object-oriented C++ language and packaged into a dynamic link library (DLL). However, the MFIRE 3.0 release made no attempt to change or improve the fire modeling algorithms inherited from its previous version, MFIRE 2.20. This paper reports on improvements that have been made to the fire modeling capabilities of MFIRE 3.0 since its release. These improvements include the addition of fire source models of the t-squared fire and heat release rate curve data file, the addition of a moving fire source for conveyor belt fire simulations, improvement of the fire location algorithm, and the identification and prediction of smoke rollback phenomena. All the improvements discussed in this paper will be termed as MFIRE 3.1 and released by NIOSH in the near future. PMID:27375301

  1. NEW IMPROVEMENTS TO MFIRE TO ENHANCE FIRE MODELING CAPABILITIES.

    PubMed

    Zhou, L; Smith, A C; Yuan, L

    2016-06-01

    NIOSH's mine fire simulation program, MFIRE, is widely accepted as a standard for assessing and predicting the impact of a fire on the mine ventilation system and the spread of fire contaminants in coal and metal/nonmetal mines, which has been used by U.S. and international companies to simulate fires for planning and response purposes. MFIRE is a dynamic, transient-state, mine ventilation network simulation program that performs normal planning calculations. It can also be used to analyze ventilation networks under thermal and mechanical influence such as changes in ventilation parameters, external influences such as changes in temperature, and internal influences such as a fire. The program output can be used to analyze the effects of these influences on the ventilation system. Since its original development by Michigan Technological University for the Bureau of Mines in the 1970s, several updates have been released over the years. In 2012, NIOSH completed a major redesign and restructuring of the program with the release of MFIRE 3.0. MFIRE's outdated FORTRAN programming language was replaced with an object-oriented C++ language and packaged into a dynamic link library (DLL). However, the MFIRE 3.0 release made no attempt to change or improve the fire modeling algorithms inherited from its previous version, MFIRE 2.20. This paper reports on improvements that have been made to the fire modeling capabilities of MFIRE 3.0 since its release. These improvements include the addition of fire source models of the t-squared fire and heat release rate curve data file, the addition of a moving fire source for conveyor belt fire simulations, improvement of the fire location algorithm, and the identification and prediction of smoke rollback phenomena. All the improvements discussed in this paper will be termed as MFIRE 3.1 and released by NIOSH in the near future.

  2. FIREPLUME model for plume dispersion from fires: Application to uranium hexafluoride cylinder fires

    SciTech Connect

    Brown, D.F.; Dunn, W.E.; Policastro, A.J.; Maloney, D.

    1997-06-01

    This report provides basic documentation of the FIREPLUME model and discusses its application to the prediction of health impacts resulting from releases of uranium hexafluoride (UF{sub 6}) in fires. The model application outlined in this report was conducted for the Draft Programmatic Environmental Impact Statement for Alternative Strategies for the Long-Term Management and Use of Depleted UF{sub 6}. The FIREPLUME model is an advanced stochastic model for atmospheric plume dispersion that predicts the downwind consequences of a release of toxic materials from an explosion or a fire. The model is based on the nonbuoyant atmospheric dispersion model MCLDM (Monte Carlo Lagrangian Dispersion Model), which has been shown to be consistent with available laboratory and field data. The inclusion of buoyancy and the addition of a postprocessor to evaluate time-varying concentrations lead to the current model. The FIREPLUME model, as applied to fire-related UF{sub 6} cylinder releases, accounts for three phases of release and dispersion. The first phase of release involves the hydraulic rupture of the cylinder due to heating of the UF{sub 6} in the fire. The second phase involves the emission of material into the burning fire, and the third phase involves the emission of material after the fire has died during the cool-down period. The model predicts the downwind concentration of the material as a function of time at any point downwind at or above the ground. All together, five fire-related release scenarios are examined in this report. For each scenario, downwind concentrations of the UF{sub 6} reaction products, uranyl fluoride and hydrogen fluoride, are provided for two meteorological conditions: (1) D stability with a 4-m/s wind speed, and (2) F stability with a 1-m/s wind speed.

  3. Fire in the Earth System: Bridging data and modeling research

    USGS Publications Warehouse

    Hantson, Srijn; Kloster, Silvia; Coughlan, Michael; Daniau, Anne-Laure; Vanniere, Boris; Bruecher, Tim; Kehrwald, Natalie; Magi, Brian I.

    2016-01-01

    Significant changes in wildfire occurrence, extent, and severity in areas such as western North America and Indonesia in 2015 have made the issue of fire increasingly salient in both the public and scientific spheres. Biomass combustion rapidly transforms land cover, smoke pours into the atmosphere, radiative heat from fires initiates dramatic pyrocumulus clouds, and the repeated ecological and atmospheric effects of fire can even impact regional and global climate. Furthermore, fires have a significant impact on human health, livelihoods, and social and economic systems.Modeling and databased methods to understand fire have rapidly coevolved over the past decade. Satellite and ground-based data about present-day fire are widely available for applications in research and fire management. Fire modeling has developed in part because of the evolution in vegetation and Earth system modeling efforts, but parameterizations and validation are largely focused on the present day because of the availability of satellite data. Charcoal deposits in sediment cores have emerged as a powerful method to evaluate trends in biomass burning extending back to the Last Glacial Maximum and beyond, and these records provide a context for present-day fire. The Global Charcoal Database version 3 compiled about 700 charcoal records and more than 1,000 records are expected for the future version 4. Together, these advances offer a pathway to explore how the strengths of fire data and fire modeling could address the weaknesses in the overall understanding of human-climate–fire linkages.A community of researchers studying fire in the Earth system with individual expertise that included paleoecology, paleoclimatology, modern ecology, archaeology, climate, and Earth system modeling, statistics, geography, biogeochemistry, and atmospheric science met at an intensive workshop in Massachusetts to explore new research directions and initiate new collaborations. Research themes, which emerged from

  4. Computer Model Documentation Guide.

    ERIC Educational Resources Information Center

    National Bureau of Standards (DOC), Washington, DC. Inst. for Computer Sciences and Technology.

    These guidelines for communicating effectively the details of computer model design and operation to persons with varying interests in a model recommend the development of four different types of manuals to meet the needs of managers, users, analysts and programmers. The guidelines for preparing a management summary manual suggest a broad spectrum…

  5. Parameterization of Fire Injection Height in Large Scale Transport Model

    NASA Astrophysics Data System (ADS)

    Paugam, R.; Wooster, M.; Atherton, J.; Val Martin, M.; Freitas, S.; Kaiser, J. W.; Schultz, M. G.

    2012-12-01

    The parameterization of fire injection height in global chemistry transport model is currently a subject of debate in the atmospheric community. The approach usually proposed in the literature is based on relationships linking injection height and remote sensing products like the Fire Radiative Power (FRP) which can measure active fire properties. In this work we present an approach based on the Plume Rise Model (PRM) developed by Freitas et al (2007, 2010). This plume model is already used in different host models (e.g. WRF, BRAMS). In its original version, the fire is modeled by: a convective heat flux (CHF; pre-defined by the land cover and evaluated as a fixed part of the total heat released) and a plume radius (derived from the GOES Wildfire-ABBA product) which defines the fire extension where the CHF is homogeneously distributed. Here in our approach the Freitas model is modified, in particular we added (i) an equation for mass conservation, (ii) a scheme to parameterize horizontal entrainment/detrainment, and (iii) a new initialization module which estimates the sensible heat released by the fire on the basis of measured FRP rather than fuel cover type. FRP and Active Fire (AF) area necessary for the initialization of the model are directly derived from a modified version of the Dozier algorithm applied to the MOD14 product. An optimization (using the simulating annealing method) of this new version of the PRM is then proposed based on fire plume characteristics derived from the official MISR plume height project and atmospheric profiles extracted from the ECMWF analysis. The data set covers the main fire region (Africa, Siberia, Indonesia, and North and South America) and is set up to (i) retain fires where plume height and FRP can be easily linked (i.e. avoid large fire cluster where individual plume might interact), (ii) keep fire which show decrease of FRP and AF area after MISR overpass (i.e. to minimize effect of the time period needed for the plume to

  6. Computer-Based Training of Cannon Fire Direction Specialists

    DTIC Science & Technology

    1993-01-01

    Course ( AOAC ), Abrams Armor Crewman One-Station Unit Training (MOS 19KOSUT), and Cannon Fire Direction Specialist Advanced Individual Training (MOS...Training AOAC Armor Oficer Adva cd Comuze AOP Army Occupational Survey Proram AR Amy Regulation ARNG Natina Guard ARPRINT Army Program for Individual...They are: Armor Officer Advanced Course ( AOAC ), Abrams Armor Crewman One-Station Unit Training (MOS 19K OSUT), and Cannmn Fire Direction Specialist

  7. Integrating simple stochastic fire spread model with the Regional Hydro-Ecological Simulation System

    NASA Astrophysics Data System (ADS)

    Kennedy, M. C.; McKenzie, D.

    2012-12-01

    Fire has an important role in watershed dynamics, and it is unclear how the interaction between fire and hydrological processes will be modified in a changing climate. Detailed landscape models of fire spread and fire effects require comprehensive data, are computationally intensive, and are subject to cumulative error from uncertainties in many parameters. In contrast, statistical models draw attributes such as extent, frequency, and severity a priori from selected distributions that are estimated from current data, implicitly assuming a stationary driving process that may not hold under climate change. We are designing a relatively simple stochastic model of fire spread (WMFire) that will be coupled with the Regional Hydro-Ecological Simulation System (RHESSys), for projecting the effects of climatic change on mountain watersheds. The model is an extension of exogenously constrained dynamic percolation (ECDP), wherein spread is controlled primarily by a spread probability from burning pixels, and which has been shown to have the capacity to identify dominant controls on cross-scale properties of low-severity fire regimes. Each year RHESSys will pass projected pixel-level values of fuel, fuel moistures, wind speed and wind direction to the fire spread model. Spread probabilities will then be calculated from the fuel load, fuel moisture, and orientation of the pixel relative to the slope gradient and wind direction. The stochastic structure of the spread model will subsume the uncertainties in future patterns of fire spread, fuels and climate. WMFire is being calibrated by and evaluated against current known fire regime properties for watersheds in the Pacific Northwest (USA) using Monte Carlo inference.

  8. Modeling the Landscape Drivers of Fire Recurrence in Sardinia (Italy)

    NASA Astrophysics Data System (ADS)

    Ricotta, Carlo; Di Vito, Stefania

    2014-06-01

    Although recurrent fire events with very short return periods have the most dangerous effects on landscape degradation, only a few papers have explored the landscape ecological factors that drive the probability of fire recurrence. In this paper we apply a habitat suitability model for analyzing the spatial relationship between a selected set of landscape factors (mainly land use types) and fire recurrence in Sardinia (Italy) in the years 2005-2010. Our results point out that fire occurrence in already burned areas is lower than expected in natural and semi-natural land cover types, like forest and shrublands. To the contrary, like in all regions where human activity is the main source of fire ignitions, the probability of fire recurrence is higher at low altitudes and close to roads and to urban and agricultural land cover types, thus showing marked preference for those landscape factors denoting higher anthropogenic ignition risk.

  9. Global biogeochemical modeling of contemporary fire emissions

    NASA Astrophysics Data System (ADS)

    Randerson, J. T.; Depaz, J. M.; van der Werf, G. R.; Giglio, L.; Morton, D. C.; Kasibhatla, P.; Defries, R. S.; Jin, Y.; Mu, M.; Collatz, G. J.

    2008-12-01

    Improved estimates of contemporary fire emissions are needed to better understand the effects of a changing fire regime on climate and air quality. At a global scale, uncertainties in fire emissions arise from several sources, including estimates of burned area, aboveground biomass, combustion completeness, and emission factors. The development of long-term time series requires addressing additional sources of uncertainty related to the integration of different satellite fire products, the representation of organic soils and peatlands, and the use of fire in the deforestation process. Here we describe improvements to a global fire emissions time series (Global Fire Emissions Database version 3) that reduce uncertainties associated with many of the factors described above. We then characterized long-term trends in fire emissions for different continental-scale regions during 1996-2007. Using South America as an example, we show how climate and human activity contribute to interannual variability in emissions and how the spatial pattern of emissions has changed over time. In a final step we use atmospheric observations of carbon monoxide (CO) from Measurements Of Pollution In The Troposphere (MOPITT) and Tropospheric Emission Spectrometer (TES) to refine and validate our bottom-up emissions estimates for South America.

  10. Application of fire and evacuation models in evaluation of fire safety in railway tunnels

    NASA Astrophysics Data System (ADS)

    Cábová, Kamila; Apeltauer, Tomáš; Okřinová, Petra; Wald, František

    2017-09-01

    The paper describes an application of numerical simulation of fire dynamics and evacuation of people in a tunnel. The software tool Fire Dynamics Simulator is used to simulate temperature resolution and development of smoke in a railway tunnel. Comparing to temperature curves which are usually used in the design stage results of the model show that the numerical model gives lower temperature of hot smoke layer. Outputs of the numerical simulation of fire also enable to improve models of evacuation of people during fires in tunnels. In the presented study the calculated high of smoke layer in the tunnel is in 10 min after the fire ignition lower than the level of 2.2 m which is considered as the maximal limit for safe evacuation. Simulation of the evacuation process in bigger scale together with fire dynamics can provide very valuable information about important security conditions like Available Safe Evacuation Time (ASET) vs Required Safe Evacuation Time (RSET). On given example in software EXODUS the paper summarizes selected results of evacuation model which should be in mind of a designer when preparing an evacuation plan.

  11. Computationally modeling interpersonal trust.

    PubMed

    Lee, Jin Joo; Knox, W Bradley; Wormwood, Jolie B; Breazeal, Cynthia; Desteno, David

    2013-01-01

    We present a computational model capable of predicting-above human accuracy-the degree of trust a person has toward their novel partner by observing the trust-related nonverbal cues expressed in their social interaction. We summarize our prior work, in which we identify nonverbal cues that signal untrustworthy behavior and also demonstrate the human mind's readiness to interpret those cues to assess the trustworthiness of a social robot. We demonstrate that domain knowledge gained from our prior work using human-subjects experiments, when incorporated into the feature engineering process, permits a computational model to outperform both human predictions and a baseline model built in naiveté of this domain knowledge. We then present the construction of hidden Markov models to investigate temporal relationships among the trust-related nonverbal cues. By interpreting the resulting learned structure, we observe that models built to emulate different levels of trust exhibit different sequences of nonverbal cues. From this observation, we derived sequence-based temporal features that further improve the accuracy of our computational model. Our multi-step research process presented in this paper combines the strength of experimental manipulation and machine learning to not only design a computational trust model but also to further our understanding of the dynamics of interpersonal trust.

  12. Computationally modeling interpersonal trust

    PubMed Central

    Lee, Jin Joo; Knox, W. Bradley; Wormwood, Jolie B.; Breazeal, Cynthia; DeSteno, David

    2013-01-01

    We present a computational model capable of predicting—above human accuracy—the degree of trust a person has toward their novel partner by observing the trust-related nonverbal cues expressed in their social interaction. We summarize our prior work, in which we identify nonverbal cues that signal untrustworthy behavior and also demonstrate the human mind's readiness to interpret those cues to assess the trustworthiness of a social robot. We demonstrate that domain knowledge gained from our prior work using human-subjects experiments, when incorporated into the feature engineering process, permits a computational model to outperform both human predictions and a baseline model built in naiveté of this domain knowledge. We then present the construction of hidden Markov models to investigate temporal relationships among the trust-related nonverbal cues. By interpreting the resulting learned structure, we observe that models built to emulate different levels of trust exhibit different sequences of nonverbal cues. From this observation, we derived sequence-based temporal features that further improve the accuracy of our computational model. Our multi-step research process presented in this paper combines the strength of experimental manipulation and machine learning to not only design a computational trust model but also to further our understanding of the dynamics of interpersonal trust. PMID:24363649

  13. Modeling fire susceptibility to delineate wildland-urban interface for municipal-scale fire risk management.

    PubMed

    Whitman, Ellen; Rapaport, Eric; Sherren, Kate

    2013-12-01

    The wildland-urban interface (WUI) is the region where development meets and intermingles with wildlands. The WUI has an elevated fire risk due to the proximity of development and residents to wildlands with natural wildfire regimes. Existing methods of delineating WUI are typically applied over a large region, use proxies for risk, and do not consider site-specific fire hazard drivers. While these models are appropriate for federal and provincial risk management, municipal managers require models intended for smaller regions. The model developed here uses the Burn-P3 fire behavior model to model WUI from local fire susceptibility (FS) in two study communities. Forest fuel code (FFC) maps for the study communities were modified using remote sensing data to produce detailed forest edges, including ladder fuels, update data currency, and add buildings and roads. The modified FFC maps used in Burn-P3 produced bimodal FS distributions for each community. The WUI in these communities was delineated as areas within community bounds where FS was greater than or equal to -1 SD from the mean FS value ([Formula: see text]), which fell in the trough of the bimodal distribution. The WUI so delineated conformed to the definition of WUI. This model extends WUI modeling for broader risk management initiatives for municipal management of risk, as it (a) considers site-specific drivers of fire behavior; (b) models risk, represented by WUI, specific to a community; and, (c) does not use proxies for risk.

  14. Reaction-to-fire testing and modeling for wood products

    Treesearch

    Mark A. Dietenberger; Robert H. White

    2001-01-01

    In this review we primarily discuss our use of the oxygen consumption calorimeter (ASTM E1354 for cone calorimeter and ISO9705 for room/corner tests) and fire growth modeling to evaluate treated wood products. With recent development towards performance-based building codes, new methodology requires engineering calculations of various fire growth scenarios. The initial...

  15. Experimental and numerical modeling of shrub crown fire initiation

    Treesearch

    Watcharapong Tachajapong; Jesse Lozano; Shakar Mahalingam; Xiangyang Zhou; David Weise

    2009-01-01

    The transition of fire from dry surface fuels to wet shrub crown fuels was studied using laboratory experiments and a simple physical model to gain a better understanding of the transition process. In the experiments, we investigated the effects of varying vertical distances between surface and crown fuels (crown base height), and of the wind speed on crown fire...

  16. Modeling wind adjustment factor and midflame wind speed for Rothermel's surface fire spread model

    Treesearch

    Patricia L. Andrews

    2012-01-01

    Rothermel's surface fire spread model was developed to use a value for the wind speed that affects surface fire, called midflame wind speed. Models have been developed to adjust 20-ft wind speed to midflame wind speed for sheltered and unsheltered surface fuel. In this report, Wind Adjustment Factor (WAF) model equations are given, and the BehavePlus fire modeling...

  17. BLAZE, a novel Fire-Model for the CABLE Land-Surface Model applied to a Re-Assessment of the Australian Continental Carbon Budget

    NASA Astrophysics Data System (ADS)

    Nieradzik, L. P.; Haverd, V. E.; Briggs, P.; Meyer, C. P.; Canadell, J.

    2015-12-01

    Fires play a major role in the carbon-cycle and the development of global vegetation, especially on the continent of Australia, where vegetation is prone to frequent fire occurences and where regional composition and stand-age distribution is regulated by fire. Furthermore, the probable changes of fire behaviour under a changing climate are still poorly understood and require further investigation.In this presentation we introduce the fire-model BLAZE (BLAZe induced land-atmosphere flux Estimator), designed for a novel approach to simulate fire-frequencies, fire-intensities, fire related fluxes and the responses in vegetation. Fire frequencies are prescribed using SIMFIRE (Knorr et al., 2014) or GFED3 (e.g. Giglio et al., 2013). Fire-Line-Intensity (FLI) is computed from meteorological information and fuel loads which are state variables within the C-cycle component of CABLE (Community Atmosphere-Biosphere-Land Exchange model). This FLI is used as an input to the tree-demography model POP(Population-Order-Physiology; Haverd et al., 2014). Within POP the fire-mortality depends on FLI and tree height distribution. Intensity-dependent combustion factors (CF) are then generated for and applied to live and litter carbon pools as well as the transfers from live pools to litter caused by fire. Thus, both fire and stand characteristics are taken into account which has a legacy effect on future events. Gross C-CO2 emissions from Australian wild fires are larger than Australian territorial fossil fuel emissions. However, the net effect of fire on the Australian terrestrial carbon budget is unknown. We address this by applying the newly-developed fire module, integrated within the CABLE land surface model, and optimised for the Australian region, to a reassessment of the Australian Terrestrial Carbon Budget.

  18. Computational models of planning.

    PubMed

    Geffner, Hector

    2013-07-01

    The selection of the action to do next is one of the central problems faced by autonomous agents. Natural and artificial systems address this problem in various ways: action responses can be hardwired, they can be learned, or they can be computed from a model of the situation, the actions, and the goals. Planning is the model-based approach to action selection and a fundamental ingredient of intelligent behavior in both humans and machines. Planning, however, is computationally hard as the consideration of all possible courses of action is not computationally feasible. The problem has been addressed by research in Artificial Intelligence that in recent years has uncovered simple but powerful computational principles that make planning feasible. The principles take the form of domain-independent methods for computing heuristics or appraisals that enable the effective generation of goal-directed behavior even over huge spaces. In this paper, we look at several planning models, at methods that have been shown to scale up to large problems, and at what these methods may suggest about the human mind. WIREs Cogn Sci 2013, 4:341-356. doi: 10.1002/wcs.1233 The authors have declared no conflicts of interest for this article. For further resources related to this article, please visit the WIREs website. Copyright © 2013 John Wiley & Sons, Ltd.

  19. Gaps in Data and Modeling Tools for Understanding Fire and Fire Effects in Tundra Ecosystems

    NASA Astrophysics Data System (ADS)

    French, N. H.; Miller, M. E.; Loboda, T. V.; Jenkins, L. K.; Bourgeau-Chavez, L. L.; Suiter, A.; Hawkins, S. M.

    2013-12-01

    As the ecosystem science community learns more about tundra ecosystems and disturbance in tundra, a review of base data sets and ecological field data for the region shows there are many gaps that need to be filled. In this paper we will review efforts to improve our knowledge of the occurrence and impacts of fire in the North American tundra region completed under a NASA Terrestrial Ecology grant. Our main source of information is remote sensing data from satellite sensors and ecological data from past and recent field data collections by our team, collaborators, and others. Past fire occurrence is not well known for this region compared with other North American biomes. In this presentation we review an effort to use a semi-automated detection algorithm to identify past fire occurrence using the Landsat TM/ETM+ archives, pointing out some of the still-unaddressed issues for a full understanding of fire regime for the region. For this task, fires in Landsat scenes were mapped using the Random Forest classifier (Breiman 2001) to automatically detect potential burn scars. Random Forests is an ensemble classifier that employs machine learning to build a large collection of decision trees that are grown from a random selection of user supplied training data. A pixel's classification is then determined by which class receives the most 'votes' from each tree. We also review the use fire location records and existing modeling methods to quantify emissions from these fires. Based on existing maps of vegetation fuels, we used the approach developed for the Wildland Fire Emissions Information System (WFEIS; French et al. 2011) to estimate emissions across the tundra region. WFEIS employs the Consume model (http://www.fs.fed.us/pnw/fera/research/smoke/consume/index.shtml) to estimate emissions by applying empirically developed relationships between fuels, fire conditions (weather-based fire indexes), and emissions. Here again, we will review the gaps in data and modeling

  20. Modelling threats to water quality from fire suppression chemicals and post-fire erosion

    NASA Astrophysics Data System (ADS)

    Hyde, Kevin; Ziemniak, Chris; Elliot, William; Samuels, William

    2014-05-01

    Misapplication of fire retardant chemicals into streams and rivers may threaten aquatic life. The possible threat depends on the contaminant concentration that, in part, is controlled by dispersion within flowing water. In the event of a misapplication, methods are needed to rapidly estimate the chemical mass entering the waterway and the dispersion and transport within the system. Here we demonstrate a new tool that calculates the chemical mass based on aircraft delivery system, fire chemical type, and stream and intersect geometry. The estimated mass is intended to be transferred into a GIS module that uses real-time stream data to map and simulate the dispersion and transport downstream. This system currently accounts only for aqueous transport. We envision that the GIS module can be modified to incorporate sediment transport, specifically to model movement of sediments from post-fire erosion. This modification could support assessment of threats of post-fire erosion to water quality and water supply systems.

  1. A comparison of geospatially modeled fire behavior and fire management utility of three data sources in the southeastern United States.

    SciTech Connect

    Hollingsworth, LaWen T.; Kurth, Laurie,; Parresol, Bernard, R.; Ottmar, Roger, D.; Prichard, Susan J.

    2012-01-01

    Landscape-scale fire behavior analyses are important to inform decisions on resource management projects that meet land management objectives and protect values from adverse consequences of fire. Deterministic and probabilistic geospatial fire behavior analyses are conducted with various modeling systems including FARSITE, FlamMap, FSPro, and Large Fire Simulation System. The fundamental fire intensity algorithms in these systems require surface fire behavior fuel models and canopy cover to model surface fire behavior. Canopy base height, stand height, and canopy bulk density are required in addition to surface fire behavior fuel models and canopy cover to model crown fire activity. Several surface fuel and canopy classification efforts have used various remote sensing and ecological relationships as core methods to develop the spatial layers. All of these methods depend upon consistent and temporally constant interpretations of crown attributes and their ecological conditions to estimate surface fuel conditions. This study evaluates modeled fire behavior for an 80,000 ha tract of land in the Atlantic Coastal Plain of the southeastern US using three different data sources. The Fuel Characteristic Classification System (FCCS) was used to build fuelbeds from intensive field sampling of 629 plots. Custom fire behavior fuel models were derived from these fuelbeds. LANDFIRE developed surface fire behavior fuel models and canopy attributes for the US using satellite imagery informed by field data. The Southern Wildfire Risk Assessment (SWRA) developed surface fire behavior fuel models and canopy cover for the southeastern US using satellite imagery. Differences in modeled fire behavior, data development, and data utility are summarized to assist in determining which data source may be most applicable for various land management activities and required analyses. Characterizing fire behavior under different fuel relationships provides insights for natural ecological

  2. Aspects and Strategies of Numerical Modelling of Underground Coal Fires

    NASA Astrophysics Data System (ADS)

    Wuttke, M. W.; Han, J.; Liu, G.; Kessels, W.; Schmidt, M.; Gusat, D.; Fischer, Chr.; Hirner, A.; Meyer, U.

    2009-04-01

    Numerical modelling of underground coal fires has become a valuable tool even for practical fire extinction work. The approaches, methods and finally codes that are used depend on the targets that are aimed at by the particular modelling task. The most general one is to fully understand the processes that sustain or suppress the fire. Another purpose is to produce realistic data for regions that are not accessible (e . g. underneath a burning coal seam) or couldn't be investigated (e.g due to limited resources) to estimate the complete energy budget of the fire. Last but not least one would like to forecast the fire dynamics to predict the future damage or to assess the effectivenees of extinction work. These purposes require the consideration of all aspects with respect to thermal, hydraulic, mechanical and chemical (THMC) processes. At the moment there is no single code that completely covers all these aspects with every degree of complexity. Within the Sino-German project "Innovative Technologies for Exploration, Extinction and Monitoring of Coal Fires in North China" we apply existing codes with different foci with respect to THMC processes and try to combine all codes to one comprehensive model. Besides the sophisticated academic modelling approach we also pursue the concept of "Onsite" modelling to enable fire fighting personnel to perform simplified modelling tasks even by means of web-based applications.

  3. Cellular automaton modelling of lightning-induced and man made forest fires

    NASA Astrophysics Data System (ADS)

    Krenn, R.; Hergarten, S.

    2009-10-01

    The impact of forest fires on nature and civilisation is conflicting: on one hand, they play an irreplaceable role in the natural regeneration process, but on the other hand, they come within the major natural hazards in many regions. Their frequency-area distributions show power-law behaviour with scaling exponents α in a quite narrow range, relating wildfire research to the theoretical framework of self-organised criticality. Examples of self-organised critical behaviour can be found in computer simulations of simple cellular automaton models. The established self-organised critical Drossel-Schwabl forest fire model is one of the most widespread models in this context. Despite its qualitative agreement with event-size statistics from nature, its applicability is still questioned. Apart from general concerns that the Drossel-Schwabl model apparently oversimplifies the complex nature of forest dynamics, it significantly overestimates the frequency of large fires. We present a modification of the model rules that distinguishes between lightning-induced and man made forest fires and enables a systematic increase of the scaling exponent α by approximately 1/3. In addition, combined simulations using both the original and the modified model rules predict a dependence of the overall event-size distribution on the ratio of lightning induced and man made fires as well as a splitting of their partial distributions. Lightning is identified as the dominant mechanism in the regime of the largest fires. The results are confirmed by the analysis of the Canadian Large Fire Database and suggest that lightning-induced and man made forest fires cannot be treated separately in wildfire modelling, hazard assessment and forest management.

  4. How to generate and interpret fire characteristics charts for surface and crown fire behavior

    Treesearch

    Patricia L. Andrews; Faith Ann Heinsch; Luke Schelvan

    2011-01-01

    A fire characteristics chart is a graph that presents primary related fire behavior characteristics-rate of spread, flame length, fireline intensity, and heat per unit area. It helps communicate and interpret modeled or observed fire behavior. The Fire Characteristics Chart computer program plots either observed fire behavior or values that have been calculated by...

  5. Stochastic fire-diffuse-fire model with realistic cluster dynamics

    NASA Astrophysics Data System (ADS)

    Calabrese, Ana; Fraiman, Daniel; Zysman, Daniel; Ponce Dawson, Silvina

    2010-09-01

    Living organisms use waves that propagate through excitable media to transport information. Ca2+ waves are a paradigmatic example of this type of processes. A large hierarchy of Ca2+ signals that range from localized release events to global waves has been observed in Xenopus laevis oocytes. In these cells, Ca2+ release occurs trough inositol 1,4,5-trisphosphate receptors (IP3Rs) which are organized in clusters of channels located on the membrane of the endoplasmic reticulum. In this article we construct a stochastic model for a cluster of IP3R ’s that replicates the experimental observations reported in [D. Fraiman , Biophys. J. 90, 3897 (2006)10.1529/biophysj.105.075911]. We then couple this phenomenological cluster model with a reaction-diffusion equation, so as to have a discrete stochastic model for calcium dynamics. The model we propose describes the transition regimes between isolated release and steadily propagating waves as the IP3 concentration is increased.

  6. Modeling fuels and fire effects in 3D: Model description and applications

    Treesearch

    Francois Pimont; Russell Parsons; Eric Rigolot; Francois de Coligny; Jean-Luc Dupuy; Philippe Dreyfus; Rodman R. Linn

    2016-01-01

    Scientists and managers critically need ways to assess how fuel treatments alter fire behavior, yet few tools currently exist for this purpose.We present a spatially-explicit-fuel-modeling system, FuelManager, which models fuels, vegetation growth, fire behavior (using a physics-based model, FIRETEC), and fire effects. FuelManager's flexible approach facilitates...

  7. Modelling fire frequency and area burned across phytoclimatic regions in Spain using reanalysis data and the Canadian Fire Weather Index System

    NASA Astrophysics Data System (ADS)

    Bedia, J.; Herrera, S.; Gutiérrez, J. M.

    2013-09-01

    We develop fire occurrence and burned area models in peninsular Spain, an area of high variability in climate and fuel types, for the period 1990-2008. We based the analysis on a phytoclimatic classification aiming to the stratification of the territory into homogeneous units in terms of climatic and fuel type characteristics, allowing to test model performance under different climatic and fuel conditions. We used generalized linear models (GLM) and multivariate adaptive regression splines (MARS) as modelling algorithms and temperature, relative humidity, precipitation and wind speed, taken from the ERA-Interim reanalysis, as well as the components of the Canadian Forest Fire Weather Index (FWI) System as predictors. We also computed the standardized precipitation-evapotranspiration index (SPEI) as an additional predictor for the models of burned area. We found two contrasting fire regimes in terms of area burned and number of fires: one characterized by a bimodal annual pattern, characterizing the Nemoral and Oro-boreal phytoclimatic types, and another one exhibiting an unimodal annual cycle, with the fire season concentrated in the summer months in the Mediterranean and Arid regions. The fire occurrence models attained good skill in most of the phytoclimatic zones considered, yielding in some zones notably high correlation coefficients between the observed and modelled inter-annual fire frequencies. Total area burned also exhibited a high dependence on the meteorological drivers, although their ability to reproduce the observed annual burned area time series was poor in most cases. We identified temperature and some FWI system components as the most important explanatory variables, and also SPEI in some of the burned area models, highlighting the adequacy of the FWI system for fire modelling applications and leaving the door opened to the development a more complex modelling framework based on these predictors. Furthermore, we demonstrate the potential usefulness

  8. Mapping wildland fuels for fire management across multiple scales: integrating remote sensing, GIS, and biophysical modeling

    USGS Publications Warehouse

    Keane, Robert E.; Burgan, Robert E.; Van Wagtendonk, Jan W.

    2001-01-01

    Fuel maps are essential for computing spatial fire hazard and risk and simulating fire growth and intensity across a landscape. However, fuel mapping is an extremely difficult and complex process requiring expertise in remotely sensed image classification, fire behavior, fuels modeling, ecology, and geographical information systems (GIS). This paper first presents the challenges of mapping fuels: canopy concealment, fuelbed complexity, fuel type diversity, fuel variability, and fuel model generalization. Then, four approaches to mapping fuels are discussed with examples provided from the literature: (1) field reconnaissance; (2) direct mapping methods; (3) indirect mapping methods; and (4) gradient modeling. A fuel mapping method is proposed that uses current remote sensing and image processing technology. Future fuel mapping needs are also discussed which include better field data and fuel models, accurate GIS reference layers, improved satellite imagery, and comprehensive ecosystem models.

  9. Large eddy simulation of forest canopy flow for wildland fire modeling

    Treesearch

    Eric Mueller; William Mell; Albert Simeoni

    2014-01-01

    Large eddy simulation (LES) based computational fluid dynamics (CFD) simulators have obtained increasing attention in the wildland fire research community, as these tools allow the inclusion of important driving physics. However, due to the complexity of the models, individual aspects must be isolated and tested rigorously to ensure meaningful results. As wind is a...

  10. Application of computer vision in studying fire plume behavior of tilting flames

    NASA Astrophysics Data System (ADS)

    Aminfar, Amirhessam; Cobian Iñiguez, Jeanette; Pham, Stephanie; Chong, Joey; Burke, Gloria; Weise, David; Princevac, Marko

    2016-11-01

    With the development in computer sciences especially in the field of computer vision, image processing has become an inevitable part of flow visualization. Computer vision can be used to visualize flow structure and to quantify its properties. We used a computer vision algorithm to study fire plume tilting when the fire is interacting with a solid wall. As the fire propagates to the wall the amount of air available for the fire to consume will decrease on the wall side. Therefore, the fire will start tilting towards the wall. Aspen wood was used for the fuel source and various configurations of the fuel were investigated. The plume behavior was captured using a digital camera. In the post processing, the flames were isolated from the image by using edge detection technics, making it possible to develop an algorithm to calculate flame height and flame orientation. Moreover, by using an optical flow algorithm we were able to calculate the speed associated with the edges of the flame which is related to the flame propagation speed and effective vertical velocity of the flame. The results demonstrated that as the size of the flame was increasing, the flames started tilting towards the wall. Leading to the conclusion that there should be a critical area of fire in which the flames start to tilt. Also, the algorithm made it possible to calculate a critical distance in which the flame will start orienting towards the wall

  11. A new model of landscape-scale fire connectivity applied to resource and fire management in the Sonoran Desert, USA.

    PubMed

    Gray, Miranda E; Dickson, Brett G

    2015-06-01

    Understanding where and when on the landscape fire is likely to burn (fire likelihood) and the predicted responses of valued resources (fire effects) will lead to more effective management of wildfire risk in multiple ecosystem types. Fire is a contagious and highly unpredictable process, and an analysis of fire connectivity that incorporates stochasticity may help predict fire likelihood across large extents. We developed a model of fire connectivity based on electrical circuit theory, which is a probabilistic approach to modeling ecological flows. We first parameterized our model to reflect the synergistic influences of fuels, landscape properties, and winds on fire spread in the lower Sonoran Desert of southwestern Arizona, and then defined this landscape as an interconnected network through which to model flow (i.e., fire spread). We interpreted the mapped outputs as fire likelihood and used historical burned area data to evaluate our results. Expected fire effects were characterized based on the degree to which future fire exposure might negatively impact native plant community recovery, taking into account the impact of repeated fire and major vegetation associations. We explored fire effects within habitat for the endangered Sonoran pronghorn antelope and designated wilderness. Model results indicated that fire likelihood was higher in lower elevations, and in areas with lower slopes and topographic roughness. Fire likelihood and effects were predicted to be high in 21% of the currently occupied range of the Sonoran pronghorn and 15% of the additional habitat considered suitable. Across 16 designated wilderness areas, highest predicted fire likelihood and effects fell within low elevation wilderness areas that overlapped large fire perimeters that occurred in 2005. As ongoing changes in climate and land cover are poised to alter the fire regime across extensive and ecologically important areas in the lower Sonoran Desert, an analysis of fire likelihood and

  12. Modeling topographic influences on fuel moisture and fire danger in complex terrain to improve wildland fire management decision support

    Treesearch

    Zachary A. Holden; W. Matt Jolly

    2011-01-01

    Fire danger rating systems commonly ignore fine scale, topographically-induced weather variations. These variations will likely create heterogeneous, landscape-scale fire danger conditions that have never been examined in detail. We modeled the evolution of fuel moistures and the Energy Release Component (ERC) from the US National Fire Danger Rating System across the...

  13. Computer Modeling Of Atomization

    NASA Technical Reports Server (NTRS)

    Giridharan, M.; Ibrahim, E.; Przekwas, A.; Cheuch, S.; Krishnan, A.; Yang, H.; Lee, J.

    1994-01-01

    Improved mathematical models based on fundamental principles of conservation of mass, energy, and momentum developed for use in computer simulation of atomization of jets of liquid fuel in rocket engines. Models also used to study atomization in terrestrial applications; prove especially useful in designing improved industrial sprays - humidifier water sprays, chemical process sprays, and sprays of molten metal. Because present improved mathematical models based on first principles, they are minimally dependent on empirical correlations and better able to represent hot-flow conditions that prevail in rocket engines and are too severe to be accessible for detailed experimentation.

  14. A way forward for fire-caused tree mortality prediction: Modeling a physiological consequence of fire

    Treesearch

    Kathleen L. Kavanaugh; Matthew B. Dickinson; Anthony S. Bova

    2010-01-01

    Current operational methods for predicting tree mortality from fire injury are regression-based models that only indirectly consider underlying causes and, thus, have limited generality. A better understanding of the physiological consequences of tree heating and injury are needed to develop biophysical process models that can make predictions under changing or novel...

  15. New Model Predicts Fire Activity in South America

    NASA Image and Video Library

    UC Irvine scientist Jim Randerson discusses a new model that is able to predict fire activity in South America using sea surface temperature observations of the Pacific and Atlantic Ocean. The find...

  16. NFDRSPC: The National Fire-Danger Rating System on a Personal Computer

    Treesearch

    Bryan G. Donaldson; James T. Paul

    1990-01-01

    This user's guide is an introductory manual for using the 1988 version (Burgan 1988) of the National Fire-Danger Rating System on an IBM PC or compatible computer. NFDRSPC is a window-oriented, interactive computer program that processes observed and forecast weather with fuels data to produce NFDRS indices. Other program features include user-designed display...

  17. Parameterization of Fire Injection Height in Large Scale Transport Model

    NASA Astrophysics Data System (ADS)

    Paugam, r.; Wooster, m.; Freitas, s.; Gonzi, s.; Palmer, p.

    2012-04-01

    The parameterization of fire injection height in global chemistry transport model is currently a subject of debate in the atmospheric community. The approach usually proposed in the literature is based on relationships linking injection height and remote sensing products like the Fire Radiative Power (FRP) which can measure active fire properties. In this work we present an approach based on the Plume Rise Model (PRM) developed by Freitas et al (2007, 2010). This plume model is already used in different host models (e.g. WRF, BRAMS). In its original version, the fire is modelled by: a convective heat flux (CHF; pre-defined by the land cover and evaluated as a fixed part of the total heat released) and a plume radius (derived from the GOES Wildfire-ABBA product) which defines the fire extension where the CHF is homogeneously distributed. Here in our approach the Freitas model is modified. Major modifications are implemented in its initialisation module: (i) CHF and the Active Fire area are directly force from FRP data derived from a modified version of the Dozier algorithm applied to the MOD12 product, (ii) and a new module of the buoyancy flux calculation is implemented instead of the original module based on the Morton Taylor and Turner equation. Furthermore the dynamical core of the plume model is also modified with a new entrainment scheme inspired from latest results from shallow convection parameterization. Optimization and validation of this new version of the Freitas PRM is based on fire plume characteristics derived from the official MISR plume height project and atmospheric profile extracted from the ECMWF analysis. The data set is (i) build up to only keep fires where plume height and FRP can be easily linked (i.e. avoid large fire cluster where individual plume might interact) and (ii) split per fire land cover type to optimize the constant of the buoyancy flux module and the entrainment scheme to different fire regime. Result shows that the new PRM is

  18. Modeling Forest Understory Fires in an Eastern Amazonian Landscape

    NASA Technical Reports Server (NTRS)

    Alencar, A. A. C.; Solorzano, L. A.; Nepstad, D. C.

    2004-01-01

    Forest understory fires are an increasingly important cause of forest impoverishment in Ammonia, but little is known of the landscape characteristics and climatic phenomena that determine their occurrence. We developed empirical functions relating the occurrence of understory fires to landscape features near Paragominas, a 35- yr-old ranching and logging center in eastern Ammonia. An historical sequence of maps of forest understory fire was created based on field interviews With local farmers and Landsat TM images. Several landscape features that might explain spatial variations in the occurrence of understory fires were also mapped and co-registered for each of the sample dates, including: forest fragment size and shape, forest impoverishment through logging and understory fires, source of ignition (settlements and charcoal pits), roads, forest edges, and others. The spatial relationship between forest understory fire and each landscape characteristic was tested by regression analyses. Fire probability models were then developed for various combinations of landscape characteristics. The analyses were conducted separately for years of the El Nino Southern Oscillation (ENSO), which are associated with severe drought in eastern Amazonia, and non-ENS0 years. Most (91 %) of the forest area that burned during the 10-yr sequence caught fire during ENSO years, when severe drought may have increased both forest flammability and the escape of agricultural management fires. Forest understory fires were associated with forest edges, as reported in previous studies from Ammonia. But the strongest predictor of forest fire was the percentage of the forest fragment that had been previously logged or burned. Forest fragment size, distance to charcoal pits, distance to agricultural settlement, proximity to forest edge, and distance to roads were also correlated with forest understory fire. Logistic regression models using information on fragment degradation and distance to ignition

  19. Modeling Forest Understory Fires in an Eastern Amazonian Landscape

    NASA Technical Reports Server (NTRS)

    Alencar, A. A. C.; Solorzano, L. A.; Nepstad, D. C.

    2004-01-01

    Forest understory fires are an increasingly important cause of forest impoverishment in Ammonia, but little is known of the landscape characteristics and climatic phenomena that determine their occurrence. We developed empirical functions relating the occurrence of understory fires to landscape features near Paragominas, a 35- yr-old ranching and logging center in eastern Ammonia. An historical sequence of maps of forest understory fire was created based on field interviews With local farmers and Landsat TM images. Several landscape features that might explain spatial variations in the occurrence of understory fires were also mapped and co-registered for each of the sample dates, including: forest fragment size and shape, forest impoverishment through logging and understory fires, source of ignition (settlements and charcoal pits), roads, forest edges, and others. The spatial relationship between forest understory fire and each landscape characteristic was tested by regression analyses. Fire probability models were then developed for various combinations of landscape characteristics. The analyses were conducted separately for years of the El Nino Southern Oscillation (ENSO), which are associated with severe drought in eastern Amazonia, and non-ENS0 years. Most (91 %) of the forest area that burned during the 10-yr sequence caught fire during ENSO years, when severe drought may have increased both forest flammability and the escape of agricultural management fires. Forest understory fires were associated with forest edges, as reported in previous studies from Ammonia. But the strongest predictor of forest fire was the percentage of the forest fragment that had been previously logged or burned. Forest fragment size, distance to charcoal pits, distance to agricultural settlement, proximity to forest edge, and distance to roads were also correlated with forest understory fire. Logistic regression models using information on fragment degradation and distance to ignition

  20. Modeling Fire Emissions across Central and Southern Italy: Implications for Land and Fire Management

    NASA Astrophysics Data System (ADS)

    Bacciu, V. M.; Salis, M.; Spano, D.

    2015-12-01

    Fires play a relevant role in the global and regional carbon cycle, representing a remarkable source of CO2 and other greenhouse gases (GHG) that influence atmosphere budgets and climate. In addition, the wildfire increase projected in Southern Europe due to climate change (CC) and concurrent exacerbation of extreme weather conditions could also lead to a significant rise in GHG. Recently, in the context of the Italian National Adaptation Strategy to Climate Change (SNAC), several approaches were identified as valuable tools to adapt and mitigate the impacts of CC on wildfires, in order to reduce landscape susceptibility and to contribute to the efforts of carbon emission mitigation proposed within the Kyoto protocol. Active forest and fuel management (such as prescribed burning, fuel reduction and removal, weed and flammable shrub control, creation of fuel discontinuity) is recognised to be a key element to adapt and mitigate the impacts of CC on wildfires. Despite this, overall there is a lack of studies about the effectiveness of fire emission mitigation strategies. The current work aims to analyse the potential of a combination of fuel management practices in mitigating emissions from forest fires and evaluate valuable and viable options across Central and Southern Italy. These objectives were achieved throughout a retrospective application of an integrated approach combining a fire emission model (FOFEM - First Order Fire Effect Model) with spatially explicit, comprehensive, and accurate fire, vegetation and weather data for the period 2004-2012. Furthermore, a number of silvicultural techniques were combined to develop several fuel management scenarios and then tested to evaluate their potential in mitigating fire emissions.The preliminary results showed the crucial role of appropriate fuel, fire behavior, and weather data to reduce bias in quantifying the source and the composition of fire emissions and to attain reasonable estimations. Also, the current

  1. Quantitative Risk Modeling of Fire on the International Space Station

    NASA Technical Reports Server (NTRS)

    Castillo, Theresa; Haught, Megan

    2014-01-01

    The International Space Station (ISS) Program has worked to prevent fire events and to mitigate their impacts should they occur. Hardware is designed to reduce sources of ignition, oxygen systems are designed to control leaking, flammable materials are prevented from flying to ISS whenever possible, the crew is trained in fire response, and fire response equipment improvements are sought out and funded. Fire prevention and mitigation are a top ISS Program priority - however, programmatic resources are limited; thus, risk trades are made to ensure an adequate level of safety is maintained onboard the ISS. In support of these risk trades, the ISS Probabilistic Risk Assessment (PRA) team has modeled the likelihood of fire occurring in the ISS pressurized cabin, a phenomenological event that has never before been probabilistically modeled in a microgravity environment. This paper will discuss the genesis of the ISS PRA fire model, its enhancement in collaboration with fire experts, and the results which have informed ISS programmatic decisions and will continue to be used throughout the life of the program.

  2. Simulation models WRF-Fire for wildland fire to purpose of disaster mitigation in Indonesia (Case study: Wildland fire on September, 23th 2015 in South of Sumatera)

    NASA Astrophysics Data System (ADS)

    Anggoro, Adityo Mega; Putra, Agie Wandala; Hutasoit, Budi Saritua

    2017-07-01

    Indonesia is one of the countries known as a one of the world lungs because it has a large forest and varied species. Besides that Indonesia has frequently hit by wildfires a year, one in 2015 yesterday which was hotly discussed because of the impact of forest fires that disrupt transport activity for flights resulting from interruption of smoke from fires. Therefore, it is important to be able to model the behavior of forest fires to disaster mitigation. In this study simulated forest fires in the region of South Sumatra on September 23, 2015 by the coordinates of fires 3,17°S and 106,03°E, this information is obtained from observation satellite imagery LANDSAT8 and hotspot distribution information from LAPAN. WRF-Fire is a combination model of Weather Research and Forecasting (WRF) with dynamic ARW core with fire semi-empirical models, based on the level set method. Methods of data analysis using descriptive analysis, comparative and spatial. The results showed that the distribution pattern of the fire resulting models have similarities with observation, the fire along with the smoke moving toward the northwest, then from the simulation results of surface winds and the invasion of fire has a correlation value of 0.62. WRF-Fire models able to simulate the extent of wildland fire even though it has few results overestimate is 1.725 ha and observations is 1.709 ha, this shows that the WRF-Fire models able be used to help mitigate the catastrophic wildland fire in Indonesia.

  3. Understanding student computational thinking with computational modeling

    NASA Astrophysics Data System (ADS)

    Aiken, John M.; Caballero, Marcos D.; Douglas, Scott S.; Burk, John B.; Scanlon, Erin M.; Thoms, Brian D.; Schatz, Michael F.

    2013-01-01

    Recently, the National Research Council's framework for next generation science standards highlighted "computational thinking" as one of its "fundamental practices". 9th Grade students taking a physics course that employed the Arizona State University's Modeling Instruction curriculum were taught to construct computational models of physical systems. Student computational thinking was assessed using a proctored programming assignment, written essay, and a series of think-aloud interviews, where the students produced and discussed a computational model of a baseball in motion via a high-level programming environment (VPython). Roughly a third of the students in the study were successful in completing the programming assignment. Student success on this assessment was tied to how students synthesized their knowledge of physics and computation. On the essay and interview assessments, students displayed unique views of the relationship between force and motion; those who spoke of this relationship in causal (rather than observational) terms tended to have more success in the programming exercise.

  4. Fire Modeling Institute: FY2012 Annual Report: Bridging scientists and managers

    Treesearch

    Robin J. Innes

    2013-01-01

    The Fire Modeling Institute (FMI) brings the best available fire and fuel science and technology developed throughout the research community to bear in fire-related management issues. Although located within the Fire, Fuel, and Smoke Science Program of the U.S. Forest Service Rocky Mountain Research Station, FMI is a national and international resource, serving fire...

  5. Numerical Modelling by FLAC on Coal Fires in North China

    NASA Astrophysics Data System (ADS)

    Gusat, D.; Drebenstedt, C.

    2009-04-01

    Coal fires occur in many countries all over the world (e.g. Australia, China, India, Indonesia, USA and Russia) in underground and on surface. In China the most coal fires occur especially in the North. Economical and environmental damages are the negative effects of the coal fires: coal fires induce open fractures and fissures within the seam and neighbouring rocks. So that these are the predominant pathways for oxygen flow and exhaust gases from a coal fire. All over northern China there are a large number of coal fires, which cause and estimated yearly coal loss of between 100 and 200 million tons ([1], [2], [3]). Spontaneous combustion is a very complicated process and is influenced by number of factors. The process is an exothermic reaction in which the heat generated is dissipated by conduction to the surrounding environment, by radiation, by convection to the ventilation flow, and in some cases by evaporation of moisture from the coal [4]. The coal fires are very serious in China, and the dangerous extent of spontaneous combustion is bad which occupies about 72.9% in mining coal seams. During coal mining in China, the coal fires of spontaneous combustion are quite severity. The dangerous of coal spontaneous combustion has been in 56% of state major coalmines [5]. The 2D and 3D-simulation models describing coal fire damages are strong tools to predict fractures and fissures, to estimate the risk of coal fire propagation into neighbouring seams, to test and evaluate coal fire fighting and prevention methods. The numerical simulations of the rock mechanical model were made with the software for geomechanical and geotechnical calculations, the programs FLAC and FLAC3D [6]. To fight again the coal fires, exist several fire fighting techniques. Water, slurries or liquefied nitrogen can be injected to cool down the coal or cut of air supply with the backfill and thereby extinct the fire. Air supply also can be cut of by covering the coal by soil or sealing of the

  6. Modelling long-term fire occurrence factors in Spain by accounting for local variations with geographically weighted regression

    NASA Astrophysics Data System (ADS)

    Martínez-Fernández, J.; Chuvieco, E.; Koutsias, N.

    2013-02-01

    Humans are responsible for most forest fires in Europe, but anthropogenic factors behind these events are still poorly understood. We tried to identify the driving factors of human-caused fire occurrence in Spain by applying two different statistical approaches. Firstly, assuming stationary processes for the whole country, we created models based on multiple linear regression and binary logistic regression to find factors associated with fire density and fire presence, respectively. Secondly, we used geographically weighted regression (GWR) to better understand and explore the local and regional variations of those factors behind human-caused fire occurrence. The number of human-caused fires occurring within a 25-yr period (1983-2007) was computed for each of the 7638 Spanish mainland municipalities, creating a binary variable (fire/no fire) to develop logistic models, and a continuous variable (fire density) to build standard linear regression models. A total of 383 657 fires were registered in the study dataset. The binary logistic model, which estimates the probability of having/not having a fire, successfully classified 76.4% of the total observations, while the ordinary least squares (OLS) regression model explained 53% of the variation of the fire density patterns (adjusted R2 = 0.53). Both approaches confirmed, in addition to forest and climatic variables, the importance of variables related with agrarian activities, land abandonment, rural population exodus and developmental processes as underlying factors of fire occurrence. For the GWR approach, the explanatory power of the GW linear model for fire density using an adaptive bandwidth increased from 53% to 67%, while for the GW logistic model the correctly classified observations improved only slightly, from 76.4% to 78.4%, but significantly according to the corrected Akaike Information Criterion (AICc), from 3451.19 to 3321.19. The results from GWR indicated a significant spatial variation in the local

  7. Computer modeling of polymers

    NASA Technical Reports Server (NTRS)

    Green, Terry J.

    1988-01-01

    A Polymer Molecular Analysis Display System (p-MADS) was developed for computer modeling of polymers. This method of modeling allows for the theoretical calculation of molecular properties such as equilibrium geometries, conformational energies, heats of formations, crystal packing arrangements, and other properties. Furthermore, p-MADS has the following capabilities: constructing molecules from internal coordinates (bonds length, angles, and dihedral angles), Cartesian coordinates (such as X-ray structures), or from stick drawings; manipulating molecules using graphics and making hard copy representation of the molecules on a graphics printer; and performing geometry optimization calculations on molecules using the methods of molecular mechanics or molecular orbital theory.

  8. Modeling stand level carbon emissions from Canadian forest fires

    NASA Astrophysics Data System (ADS)

    de Groot, W. J.; McRae, D.

    2008-12-01

    wildland fire carbon emissions in Canada for international reporting, fire weather (FWI System) and pre-burn fuel data are used to calculate fire behaviour and determine fuel consumption for individual stand components (forest floor, aboveground live trees, standing dead snags, dead and downed woody debris) using the Boreal Fire Effects Model. A summary of these models, procedures, and levels of uncertainty, are presented.

  9. Integration of satellite fire products into MPI Earth System Model

    NASA Astrophysics Data System (ADS)

    Khlystova, Iryna G.; Kloster, Silvia

    2013-04-01

    Fires are the ubiquitous phenomenon affecting all natural biomes. Since the beginning of the satellite Era, fires are being continuously observed from satellites. The most interesting satellite parameter retrieved from satellite measurements is the burned area. Combined with information on biomass available for burning the burned area can be translated into climate relevant carbon emissions from fires into the atmosphere. In this study we integrate observed burned area into a global vegetation model to derive global fire emissions. Global continuous burned area dataset is provided by the Global Fire Emissions Dataset (GFED). GFED products were obtained from MODIS (and pre-MODIS) satellites and are available for the time period of 14 years (1997-2011). This dataset is widely used, well documented and supported by periodical updates containing new features. We integrate the global burned area product into the land model JSBACH, a part of the Earth-System model developed at the Max Plank Institute for Meteorology. The land model JSBACH simulates land biomass in terms of carbon content. Fire is an important disturbance process in the Earth's carbon cycle and affects mainly the carbon stored in vegetation. In the standard JSBACH version fire is represented by process based algorithms. Using the satellite data as an alternative we are targeting better comparability of modeled carbon emissions with independent satellite measurements of atmospheric composition. The structure of burned vegetation inside of a biome can be described as the balance between woody and herbaceous vegetation. GFED provides in addition to the burned area satellite derived information of the tree cover distribution within the burned area. Using this dataset, we can attribute the burned area to the respective simulated herbaceous or woody biomass within the vegetation model. By testing several extreme cases we evaluate the quantitative impact of vegetation balance between woody and herbaceous

  10. Villaflores: Municipal forest fire management model

    Treesearch

    Pedro Martínez Muñoz; Carlos Alberto Velázquez Sanabria

    2013-01-01

    As provided for in the General Law on Sustainable Forestry Development, the Municipality of Villaflores has worked on a continuous basis since 2002 to reduce the damage caused by forest fires as part of its working agenda, in conjunction with Federal and State agencies and NGOs. The work plan has the following phases: a) Inter-agency coordination:...

  11. Integrating fire with hydrological projections: model evaluation to identify uncertainties and tradeoffs in model complexity

    NASA Astrophysics Data System (ADS)

    Kennedy, M.; McKenzie, D.

    2013-12-01

    It is imperative for resource managers to understand how a changing climate might modify future watershed and hydrological processes, and such an understanding is incomplete if disturbances such as fire are not integrated with hydrological projections. Can a robust fire spread model be developed that approximates patterns of fire spread in response to varying topography wind patterns, and fuel loads and moistures, without requiring intensive calibration to each new study area or time frame? We assessed the performance of a stochastic model of fire spread (WMFire), integrated with the Regional Hydro-Ecological Simulation System (RHESSys), for projecting the effects of climatic change on mountain watersheds. We first use Monte Carlo inference to determine that the fire spread model is able to replicate the spatial pattern of fire spread for a contemporary wildfire in Washington State (the Tripod fire), measured by the lacunarity and fractal dimension of the fire. We then integrate a version of WMFire able to replicate the contemporary wildfire with RHESSys and simulate a New Mexico watershed over the calibration period of RHESSys (1941-1997). In comparing the fire spread model to a single contemporary wildfire we found issues in parameter identifiability for several of the nine parameters, due to model input uncertainty and insensitivity of the mathematical function to certain ranges of the parameter values. Model input uncertainty is caused by the inherent difficulty in reconstructing fuel loads and fuel moistures for a fire event after the fire has occurred, as well as by issues in translating variables relevant to hydrological processes produced by the hydrological model to those known to affect fire spread and fire severity. The first stage in the model evaluation aided the improvement of the model in both of these regards. In transporting the model to a new landscape in order to evaluate fire regimes in addition to patterns of fire spread, we find reasonable

  12. Modeling fire-induced smoke spread and carbon monoxide transportation in a long channel: Fire Dynamics Simulator comparisons with measured data.

    PubMed

    Hu, L H; Fong, N K; Yang, L Z; Chow, W K; Li, Y Z; Huo, R

    2007-02-09

    Smoke and toxic gases, such as carbon monoxide, are the most fatal factors in fires. This paper models fire-induced smoke spread and carbon monoxide transportation in an 88m long channel by Fire Dynamics Simulator (FDS) with large eddy simulation (LES). FDS is now a well-founded fire dynamics computational fluid dynamic (CFD) program, which was developed by National Institute of Standards and Technology (NIST). Two full scale experiments with fire sizes of 0.75 and 1.6MW were conducted in this channel to validate the program. The spread of the fire-induced smoke flow together with the smoke temperature distribution along the channel, and the carbon monoxide concentration at an assigned position were measured. The FDS simulation results were compared with experimental data with fairly good agreement demonstrated. The validation work is then extended to numerically study the carbon monoxide concentration distribution, both vertically and longitudinally, in this long channel. Results showed that carbon monoxide concentration increase linearly with the height above the floor and decreases exponentially with the distance away from the fire source.

  13. MIRO Computational Model

    NASA Technical Reports Server (NTRS)

    Broderick, Daniel

    2010-01-01

    A computational model calculates the excitation of water rotational levels and emission-line spectra in a cometary coma with applications for the Micro-wave Instrument for Rosetta Orbiter (MIRO). MIRO is a millimeter-submillimeter spectrometer that will be used to study the nature of cometary nuclei, the physical processes of outgassing, and the formation of the head region of a comet (coma). The computational model is a means to interpret the data measured by MIRO. The model is based on the accelerated Monte Carlo method, which performs a random angular, spatial, and frequency sampling of the radiation field to calculate the local average intensity of the field. With the model, the water rotational level populations in the cometary coma and the line profiles for the emission from the water molecules as a function of cometary parameters (such as outgassing rate, gas temperature, and gas and electron density) and observation parameters (such as distance to the comet and beam width) are calculated.

  14. Modeling the spreading of large-scale wildland fires

    Treesearch

    Mohamed Drissi

    2015-01-01

    The objective of the present study is twofold. First, the last developments and validation results of a hybrid model designed to simulate fire patterns in heterogeneous landscapes are presented. The model combines the features of a stochastic small-world network model with those of a deterministic semi-physical model of the interaction between burning and non-burning...

  15. Modelling wildland fire propagation by tracking random fronts

    NASA Astrophysics Data System (ADS)

    Pagnini, G.; Mentrelli, A.

    2013-11-01

    Wildland fire propagation is studied in literature by two alternative approaches, namely the reaction-diffusion equation and the level-set method. These two approaches are considered alternative each other because the solution of the reaction-diffusion equation is generally a continuous smooth function that has an exponential decay and an infinite support, while the level-set method, which is a front tracking technique, generates a sharp function with a finite support. However, these two approaches can indeed be considered complementary and reconciled. Turbulent hot-air transport and fire spotting are phenomena with a random character that are extremely important in wildland fire propagation. As a consequence the fire front gets a random character, too. Hence a tracking method for random fronts is needed. In particular, the level-set contourn is here randomized accordingly to the probability density function of the interface particle displacement. Actually, when the level-set method is developed for tracking a front interface with a random motion, the resulting averaged process emerges to be governed by an evolution equation of the reaction-diffusion type. In this reconciled approach, the rate of spread of the fire keeps the same key and characterizing role proper to the level-set approach. The resulting model emerges to be suitable to simulate effects due to turbulent convection as fire flank and backing fire, the faster fire spread because of the actions by hot air pre-heating and by ember landing, and also the fire overcoming a firebreak zone that is a case not resolved by models based on the level-set method. Moreover, from the proposed formulation it follows a correction for the rate of spread formula due to the mean jump-length of firebrands in the downwind direction for the leeward sector of the fireline contour.

  16. Computer modeling of photodegradation

    NASA Technical Reports Server (NTRS)

    Guillet, J.

    1986-01-01

    A computer program to simulate the photodegradation of materials exposed to terrestrial weathering environments is being developed. Input parameters would include the solar spectrum, the daily levels and variations of temperature and relative humidity, and materials such as EVA. A brief description of the program, its operating principles, and how it works was initially described. After that, the presentation focuses on the recent work of simulating aging in a normal, terrestrial day-night cycle. This is significant, as almost all accelerated aging schemes maintain a constant light illumination without a dark cycle, and this may be a critical factor not included in acceleration aging schemes. For outdoor aging, the computer model is indicating that the night dark cycle has a dramatic influence on the chemistry of photothermal degradation, and hints that a dark cycle may be needed in an accelerated aging scheme.

  17. FARSITE: a fire area simulator for fire managers

    Treesearch

    Mark A. Finney

    1995-01-01

    A fire growth model (FARSITE) has been developed for use on personal computers (PC’s). Because PC’s are commonly used by land and fire managers, this portable platform would be an accustomed means to bring fire growth modeling technology to management applications. The FARSITE model is intended for use in projecting the growth of prescribed natural fires for wilderness...

  18. Using Computational Fluid Dynamics in the forensic analysis of a prison fire.

    PubMed

    Jahn, Wolfram; Gonzalez, Orelvis; de Dios Rivera, Juan; Torero, José Luis

    2015-08-01

    On the 8th of December of 2010 a fire killed 81 inmates in a Chilean prison. While the collected evidence (including eye witness' accounts) indicated an intentional fire, started by a group of inmates who were fighting against another group and who ignited a mattress and threw it over a bunk bed inside the cell, it could not be established how fast the fire grew and whether the prison guards acted promptly enough to prevent the tragedy. In this context, the public defender office in charge of the case requested an independent investigation in order to determine the approximated time the fire started, and the temperature evolution of the padlocks at the cell doors during the initial stage, based on the construction characteristics of the prison, the existing materials and the evidence collected during the investigation. Computational Fluid Dynamics (CFD) were used to analyse the movement of the smoke and to match the first appearance of smoke on CCTV recordings at locations away from the fire, allowing for the estimation of the time-line of events. The padlock temperatures as a result of hot gases from the fire was also simulated. It was shown that the fire grew quickly and became uncontrollable before the guards could intervene. By the time the guards arrived at the cells' door, the padlocks were shown to be too hot to be handled without protection.

  19. Use of models to study forest fire behavior

    Treesearch

    Wallace L. Fons

    1961-01-01

    The U.S. Forest Service has started a laboratory study with the ultimate objective of determining model laws for fire behavior. The study includes an examination of the effect of such variables as species of wood, density of wood, moisture content, size of fuel particle, spacing, dimensions of fuel bed, wind, and slope on the rate of spread of fire and the partition of...

  20. Application of wildfire spread and behavior models to assess fire probability and severity in the Mediterranean region

    NASA Astrophysics Data System (ADS)

    Salis, Michele; Arca, Bachisio; Bacciu, Valentina; Spano, Donatella; Duce, Pierpaolo; Santoni, Paul; Ager, Alan; Finney, Mark

    2010-05-01

    Characterizing the spatial pattern of large fire occurrence and severity is an important feature of the fire management planning in the Mediterranean region. The spatial characterization of fire probabilities, fire behavior distributions and value changes are key components for quantitative risk assessment and for prioritizing fire suppression resources, fuel treatments and law enforcement. Because of the growing wildfire severity and frequency in recent years (e.g.: Portugal, 2003 and 2005; Italy and Greece, 2007 and 2009), there is an increasing demand for models and tools that can aid in wildfire prediction and prevention. Newer wildfire simulation systems offer promise in this regard, and allow for fine scale modeling of wildfire severity and probability. Several new applications has resulted from the development of a minimum travel time (MTT) fire spread algorithm (Finney, 2002), that models the fire growth searching for the minimum time for fire to travel among nodes in a 2D network. The MTT approach makes computationally feasible to simulate thousands of fires and generate burn probability and fire severity maps over large areas. The MTT algorithm is imbedded in a number of research and fire modeling applications. High performance computers are typically used for MTT simulations, although the algorithm is also implemented in the FlamMap program (www.fire.org). In this work, we described the application of the MTT algorithm to estimate spatial patterns of burn probability and to analyze wildfire severity in three fire prone areas of the Mediterranean Basin, specifically Sardinia (Italy), Sicily (Italy) and Corsica (France) islands. We assembled fuels and topographic data for the simulations in 500 x 500 m grids for the study areas. The simulations were run using 100,000 ignitions under weather conditions that replicated severe and moderate weather conditions (97th and 70th percentile, July and August weather, 1995-2007). We used both random ignition locations

  1. A comparison of geospatially modeled fire behavior and potential application to fire and fuels management for the Savannah River Site.

    SciTech Connect

    Kurth, Laurie; Hollingsworth, LaWen; Shea, Dan

    2011-12-20

    This study evaluates modeled fire behavior for the Savannah River Site in the Atlantic Coastal Plain of the southeastern U.S. using three data sources: FCCS, LANDFIRE, and SWRA. The Fuel Characteristic Classification System (FCCS) was used to build fuelbeds from intensive field sampling of 629 plots. Custom fire behavior fuel models were derived from these fuelbeds. LANDFIRE developed surface fire behavior fuel models and canopy attributes for the U.S. using satellite imagery informed by field data. The Southern Wildfire Risk Assessment (SWRA) developed surface fire behavior fuel models and canopy cover for the southeastern U.S. using satellite imagery.

  2. Computer cast blast modelling

    SciTech Connect

    Chung, S.; McGill, M.; Preece, D.S.

    1994-07-01

    Cast blasting can be designed to utilize explosive energy effectively and economically for coal mining operations to remove overburden material. The more overburden removed by explosives, the less blasted material there is left to be transported with mechanical equipment, such as draglines and trucks. In order to optimize the percentage of rock that is cast, a higher powder factor than normal is required plus an initiation technique designed to produce a much greater degree of horizontal muck movement. This paper compares two blast models known as DMC (Distinct Motion Code) and SABREX (Scientific Approach to Breaking Rock with Explosives). DMC, applies discrete spherical elements interacted with the flow of explosive gases and the explicit time integration to track particle motion resulting from a blast. The input to this model includes multi-layer rock properties, and both loading geometry and explosives equation-of-state parameters. It enables the user to have a wide range of control over drill pattern and explosive loading design parameters. SABREX assumes that heave process is controlled by the explosive gases which determines the velocity and time of initial movement of blocks within the burden, and then tracks the motion of the blocks until they come to a rest. In order to reduce computing time, the in-flight collisions of blocks are not considered and the motion of the first row is made to limit the motion of subsequent rows. Although modelling a blast is a complex task, the DMC can perform a blast simulation in 0.5 hours on the SUN SPARCstation 10--41 while the new SABREX 3.5 produces results of a cast blast in ten seconds on a 486-PC computer. Predicted percentage of cast and face velocities from both computer codes compare well with the measured results from a full scale cast blast.

  3. Modeling carbon monoxide spread in underground mine fires.

    PubMed

    Yuan, Liming; Zhou, Lihong; Smith, Alex C

    2016-05-05

    Carbon monoxide (CO) poisoning is a leading cause of mine fire fatalities in underground mines. To reduce the hazard of CO poisoning in underground mines, it is important to accurately predict the spread of CO in underground mine entries when a fire occurs. This paper presents a study on modeling CO spread in underground mine fires using both the Fire Dynamics Simulator (FDS) and the MFIRE programs. The FDS model simulating part of the mine ventilation network was calibrated using CO concentration data from full-scale mine fire tests. The model was then used to investigate the effect of airflow leakage on CO concentration reduction in the mine entries. The inflow of fresh air at the leakage location was found to cause significant CO reduction. MFIRE simulation was conducted to predict the CO spread in the entire mine ventilation network using both a constant heat release rate and a dynamic fire source created from FDS. The results from both FDS and MFIRE simulations are compared and the implications of the improved MFIRE capability are discussed.

  4. Modeling carbon monoxide spread in underground mine fires

    PubMed Central

    Yuan, Liming; Zhou, Lihong; Smith, Alex C.

    2016-01-01

    Carbon monoxide (CO) poisoning is a leading cause of mine fire fatalities in underground mines. To reduce the hazard of CO poisoning in underground mines, it is important to accurately predict the spread of CO in underground mine entries when a fire occurs. This paper presents a study on modeling CO spread in underground mine fires using both the Fire Dynamics Simulator (FDS) and the MFIRE programs. The FDS model simulating part of the mine ventilation network was calibrated using CO concentration data from full-scale mine fire tests. The model was then used to investigate the effect of airflow leakage on CO concentration reduction in the mine entries. The inflow of fresh air at the leakage location was found to cause significant CO reduction. MFIRE simulation was conducted to predict the CO spread in the entire mine ventilation network using both a constant heat release rate and a dynamic fire source created from FDS. The results from both FDS and MFIRE simulations are compared and the implications of the improved MFIRE capability are discussed. PMID:27069400

  5. The Zoning of Forest Fire Potential of Gulestan Province Forests Using Granular Computing and MODIS Images

    NASA Astrophysics Data System (ADS)

    Jalilzadeh Shadlouei, A.; Delavar, M. R.

    2013-09-01

    There are many vegetation in Iran. This is because of extent of Iran and its width. One of these vegetation is forest vegetation most prevalent in Northern provinces named Guilan, Mazandaran, Gulestan, Ardebil as well as East Azerbaijan. These forests are always threatened by natural forest fires so much so that there have been reports of tens of fires in recent years. Forest fires are one of the major environmental as well as economic, social and security concerns in the world causing much damages. According to climatology, forest fires are one of the important factors in the formation and dispersion of vegetation. Also, regarding the environment, forest fires cause the emission of considerable amounts of greenhouse gases, smoke and dust into the atmosphere which in turn causes the earth temperature to rise up and are unhealthy to humans, animals and vegetation. In agriculture droughts are the usual side effects of these fires. The causes of forest fires could be categorized as either Human or Natural Causes. Naturally, it is impossible to completely contain forest fires; however, areas with high potentials of fire could be designated and analysed to decrease the risk of fires. The zoning of forest fire potential is a multi-criteria problem always accompanied by inherent uncertainty like other multi-criteria problems. So far, various methods and algorithm for zoning hazardous areas via Remote Sensing (RS) and Geospatial Information System (GIS) have been offered. This paper aims at zoning forest fire potential of Gulestan Province of Iran forests utilizing Remote Sensing, Geospatial Information System, meteorological data, MODIS images and granular computing method. Granular computing is part of granular mathematical and one way of solving multi-criteria problems such forest fire potential zoning supervised by one expert or some experts , and it offers rules for classification with the least inconsistencies. On the basis of the experts' opinion, 6 determinative

  6. HESFIRE: a global fire model to explore the role of anthropogenic and weather drivers

    SciTech Connect

    Le Page, Yannick LB; Morton, Douglas; Bond-Lamberty, Benjamin; Pereira, Jose M.; Hurtt, George C.

    2015-02-13

    Vegetation fires are a major driver of ecosystem dynamics and greenhouse gas emissions. Anticipating potential changes in fire activity and their impacts relies first on a realistic model of fire activity (e.g., fire incidence and interannual variability) and second on a model accounting for fire impacts (e.g., mortality and emissions). In this paper, we focus on our understanding of fire activity and describe a new fire model, HESFIRE (Human–Earth System FIRE), which integrates the influence of weather, vegetation characteristics, and human activities on fires in a stand-alone framework. It was developed with a particular emphasis on allowing fires to spread over consecutive days given their major contribution to burned areas in many ecosystems. A subset of the model parameters was calibrated through an optimization procedure using observation data to enhance our knowledge of regional drivers of fire activity and improve the performance of the model on a global scale. Modeled fire activity showed reasonable agreement with observations of burned area, fire seasonality, and interannual variability in many regions, including for spatial and temporal domains not included in the optimization procedure. Significant discrepancies are investigated, most notably regarding fires in boreal regions and in xeric ecosystems and also fire size distribution. The sensitivity of fire activity to model parameters is analyzed to explore the dominance of specific drivers across regions and ecosystems. The characteristics of HESFIRE and the outcome of its evaluation provide insights into the influence of anthropogenic activities and weather, and their interactions, on fire activity.

  7. The boundary vector cell model of place cell firing and spatial memory

    PubMed Central

    Barry, Caswell; Lever, Colin; Hayman, Robin; Hartley, Tom; Burton, Stephen; O'Keefe, John; Jeffery, Kate; Burgess, Neil

    2009-01-01

    We review evidence for the boundary vector cell model of the environmental determinants of the firing of hippocampal place cells. Preliminary experimental results are presented concerning the effects of addition or removal of environmental boundaries on place cell firing and evidence that boundary vector cells may exist in the subiculum. We review and update computational simulations predicting the location of human search within a virtual environment of variable geometry, assuming that boundary vector cells provide one of the input representations of location used in mammalian spatial memory. Finally, we extend the model to include experience-dependent modification of connection strengths through a BCM-like learning rule, and compare the effects to experimental data on the firing of place cells under geometrical manipulations to their environment. The relationship between neurophysiological results in rats and spatial behaviour in humans is discussed. PMID:16703944

  8. Wild Fire Emissions for the NOAA Operational HYSPLIT Smoke Model

    NASA Astrophysics Data System (ADS)

    Huang, H. C.; ONeill, S. M.; Ruminski, M.; Shafran, P.; McQueen, J.; DiMego, G.; Kondragunta, S.; Gorline, J.; Huang, J. P.; Stunder, B.; Stein, A. F.; Stajner, I.; Upadhayay, S.; Larkin, N. K.

    2015-12-01

    Particulate Matter (PM) generated from forest fires often lead to degraded visibility and unhealthy air quality in nearby and downstream areas. To provide near-real time PM information to the state and local agencies, the NOAA/National Weather Service (NWS) operational HYSPLIT (Hybrid Single Particle Lagrangian Integrated Trajectory Model) smoke modeling system (NWS/HYSPLIT smoke) provides the forecast of smoke concentration resulting from fire emissions driven by the NWS North American Model 12 km weather predictions. The NWS/HYSPLIT smoke incorporates the U.S. Forest Service BlueSky Smoke Modeling Framework (BlueSky) to provide smoke fire emissions along with the input fire locations from the NOAA National Environmental Satellite, Data, and Information Service (NESDIS)'s Hazard Mapping System fire and smoke detection system. Experienced analysts inspect satellite imagery from multiple sensors onboard geostationary and orbital satellites to identify the location, size and duration of smoke emissions for the model. NWS/HYSPLIT smoke is being updated to use a newer version of USFS BlueSky. The updated BlueSky incorporates the Fuel Characteristic Classification System version 2 (FCCS2) over the continental U.S. and Alaska. FCCS2 includes a more detailed description of fuel loadings with additional plant type categories. The updated BlueSky also utilizes an improved fuel consumption model and fire emission production system. For the period of August 2014 and June 2015, NWS/HYSPLIT smoke simulations show that fire smoke emissions with updated BlueSky are stronger than the current operational BlueSky in the Northwest U.S. For the same comparisons, weaker fire smoke emissions from the updated BlueSky were observed over the middle and eastern part of the U.S. A statistical evaluation of NWS/HYSPLIT smoke predicted total column concentration compared to NOAA NESDIS GOES EAST Aerosol Smoke Product retrievals is underway. Preliminary results show that using the newer version

  9. Application of a mesoscale atmospheric coupled fire model BRAMS-SFIRE to Alentejo wildland fire and comparison of performance with the fire model WRF-SFIRE

    NASA Astrophysics Data System (ADS)

    Menezes, Isilda; Freitas, Saulo; Stockler, Rafael; Mello, Rafael; Ribeiro, Nuno; Corte-Real, João; Surový, Peter

    2015-04-01

    Models of fuel with the identification of vegetation patterns of Montado ecosystem in Portugal was incorporated in the mesoscale Brazilian Atmospheric Modeling System (BRAMS) and coupled with a spread wildland fire model. The BRAMS-FIRE is a new system developed by the Centro de Previsão de Tempo e Estudos Climáticos (CPTEC/INPE, Brazil) and the Instituto de Ciências Agrárias e Ambientais Mediterrâneas (ICAAM, Portugal). The fire model used in this effort was originally, developed by Mandel et al. (2013) and further incorporated in the Weather Research and Forecast model (WRF). Two grids of high spatial resolution were configured with surface input data and fuel models integrated for simulations using both models BRAMS-SFIRE and WRF-SFIRE. One grid was placed in the plain land and the other one in the hills to evaluate different types of fire propagation and calibrate BRAMS-SFIRE. The objective is simulating the effects of atmospheric circulation in local scale, namely the movements of the heat front and energy release associated to it, obtained by this two models in an episode of wildland fire which took place in Alentejo area in the last decade, for application to planning and evaluations of agro wildland fire risks. We aim to model the behavior of forest fires through a set of equations whose solutions provide quantitative values of one or more variables related to the propagation of fire, described by semi-empirical expressions that are complemented by experimental data allow to obtain the main variables related advancing the perimeter of the fire, as the propagation speed, the intensity of the fire front and fuel consumption and its interaction with atmospheric dynamic system References Mandel, J., J. D. Beezley, G. Kelman, A. K. Kochanski, V. Y. Kondratenko, B. H. Lynn, and M. Vejmelka, 2013. New features in WRF-SFIRE and the wildfire forecasting and danger system in Israel. Natural Hazards and Earth System Sciences, submitted, Numerical Wildfires, Carg

  10. Computer modeling of Epilepsy

    PubMed Central

    Lytton, William W.

    2009-01-01

    Preface Epilepsy is a complex set of disorders that can involve many areas of cortex as well as underlying deep brain systems. The myriad manifestations of seizures, as varied as déjà vu and olfactory hallucination, can thereby give researchers insights into regional functions and relations. Epilepsy is also complex genetically and pathophysiologically, involving microscopic (ion channels, synaptic proteins), macroscopic (brain trauma and rewiring) and intermediate changes in a complex interplay of causality. It has long been recognized that computer modeling will be required to disentangle causality, to better understand seizure spread and to understand and eventually predict treatment efficacy. Over the past few years, substantial progress has been made modeling epilepsy at levels ranging from the molecular to the socioeconomic. We review these efforts and connect them to the medical goals of understanding and treating this disorder. PMID:18594562

  11. Computational Modeling Program

    NASA Technical Reports Server (NTRS)

    Govindan, T. R.; Davis, Robert J.

    1998-01-01

    An Integrated Product Team (IPT) has been formed at NASA Ames Research Center which has set objectives to investigate devices and processes suitable for meeting NASA requirements on ultrahigh performance computers, fast and low power devices, and high temperature wide bandgap materials. These devices may ultimately be sub-100nm feature-size. Processes and equipment must meet the stringent demands posed by the fabrication of such small devices. Until now, the reactors for Chemical Vapor Deposition (CVD) and plasma processes have been designed by trial and error procedures. Further, once the reactor is in place, optimum processing parameters are found through expensive and time-consuming experimentation. If reliable models are available that describe processes and the operation of the reactors, that chore would be reduced to a routine task while being a cost-effective option. The goal is to develop such a design tool, validate that tool using available data from current generation processes and reactors, and then use that tool to explore avenues for meeting NASA needs for ultrasmall device fabrication. Under the present grant, ARL/Penn State along with other IPT members has been developing models and computer code to meet IPT goals. Some of the accomplishments achieved during the first year of the grant are described in this report

  12. Modeling of Electrical Cable Failure in a Dynamic Assessment of Fire Risk

    NASA Astrophysics Data System (ADS)

    Bucknor, Matthew D.

    complexity to existing cable failure techniques and tuned to empirical data can better approximate the temperature response of a cables located in tightly packed cable bundles. The new models also provide a way to determine the conditions insides a cable bundle which allows for separate treatment of cables on the interior of the bundle from cables on the exterior of the bundle. The results from the DET analysis show that the overall assessed probability of cable failure can be significantly reduced by more realistically accounting for the influence that the fire brigade has on a fire progression scenario. The shielding analysis results demonstrate a significant reduction in the temperature response of a shielded versus a non-shielded cable bundle; however the computational cost of using a fire progression model that can capture these effects may be prohibitive for performing DET analyses with currently available computational fluid dynamics models and computational resources.

  13. Modeling Climate Change Impacts on Landscape Evolution, Fire, and Hydrology

    NASA Astrophysics Data System (ADS)

    Sheppard, B. S.; O Connor, C.; Falk, D. A.; Garfin, G. M.

    2015-12-01

    Landscape disturbances such as wildfire interact with climate variability to influence hydrologic regimes. We coupled landscape, fire, and hydrologic models and forced them using projected climate to demonstrate climate change impacts anticipated at Fort Huachuca in southeastern Arizona, USA. The US Department of Defense (DoD) recognizes climate change as a trend that has implications for military installations, national security and global instability. The goal of this DoD Strategic Environmental Research and Development Program (SERDP) project (RC-2232) is to provide decision making tools for military installations in the southwestern US to help them adapt to the operational realities associated with climate change. For this study we coupled the spatially explicit fire and vegetation dynamics model FireBGCv2 with the Automated Geospatial Watershed Assessment tool (AGWA) to evaluate landscape vegetation change, fire disturbance, and surface runoff in response to projected climate forcing. A projected climate stream for the years 2005-2055 was developed from the Multivariate Adaptive Constructed Analogs (MACA) 4 km statistical downscaling of the CanESM2 GCM using Representative Concentration Pathway (RCP) 8.5. AGWA, an ArcGIS add-in tool, was used to automate the parameterization and execution of the Soil Water Assessment Tool (SWAT) and the KINematic runoff and EROSion2 (KINEROS2) models based on GIS layers. Landscape raster data generated by FireBGCv2 project an increase in fire and drought associated tree mortality and a decrease in vegetative basal area over the years of simulation. Preliminary results from SWAT modeling efforts show an increase to surface runoff during years following a fire, and for future winter rainy seasons. Initial results from KINEROS2 model runs show that peak runoff rates are expected to increase 10-100 fold as a result of intense rainfall falling on burned areas.

  14. Fire

    Treesearch

    John A. Stanturf; Scott L. Goodrick

    2013-01-01

    Key FindingsClimate forecasts indicate that the South’s spring and fall wildfire seasons will be extended.Prescribed fires, currently conducted on roughly a 3 to 5 year rotation across much of the South, would need to become more frequent if conditions become drier.Major wildfire events, such as the 2007...

  15. Validation of BEHAVE fire behavior predictions in oak savannas using five fuel models

    Treesearch

    Keith Grabner; John Dwyer; Bruce Cutter

    1997-01-01

    Prescribed fire is a valuable tool in the restoration and management of oak savannas. BEHAVE, a fire behavior prediction system developed by the United States Forest Service, can be a useful tool when managing oak savannas with prescribed fire. BEHAVE predictions of fire rate-of-spread and flame length were validated using four standardized fuel models: Fuel Model 1 (...

  16. A novel Fire-Model for the CABLE Land Surface Model applied to a Re-assessment of the Australian Continental Carbon Budget

    NASA Astrophysics Data System (ADS)

    Nieradzik, L. P.; Haverd, V. E.; Briggs, P.; Meyer, C. P.; Canadell, J.

    2014-12-01

    Fires play a major role in the carbon-cycle and the development of global vegetation, especially on the continent of Australia, where vegetation is prone to frequent fire occurences and where regional composition and stand-age distribution is regulated by fire. Furthermore, the probable changes of fire behaviour under a changing climate are still poorly understood and require further investigation.In this presentation we introduce a novel approach to simulate fire-frequencies, fire-intensities and the responses in vegetation. Fire frequencies are prescribed using SIMFIRE (Knorr et al., 2014) or GFED3 (e.g. Giglio et al., 2013). Fire-Line-Intensity (FLI) is computed from meteorological information and fuel loads which are state variables within the C-cycle component of CABLE. This FLI is used as an input to the tree-demography model POP (Population-Order-Physiology; Haverd et al., 2014). Within POP the fire-mortality depends on FLI and tree height distribution.Intensity-dependent combustion factors (CF) are then generated for and applied to live and litter carbon pools as well as the transfers from live pools to litter caused by fire. Thus, both fire and stand characteristics are taken into account which has a legacy effect on future events. Gross C-CO2 emissions from Australian wild fires are larger than Australian territorial fossil fuel emissions. However, the net effect of fire on the Australian terrestrial carbon budget is unknown. We address this by applying the newly-developed fire module, integrated within the CABLE land surface model, and optimised for the Australian region, to a reassessment of the Australian Terrestrial Carbon Budget.

  17. Modeling the variability of firing rate of retinal ganglion cells.

    PubMed

    Levine, M W

    1992-12-01

    Impulse trains simulating the maintained discharges of retinal ganglion cells were generated by digital realizations of the integrate-and-fire model. If the mean rate were set by a "bias" level added to "noise," the variability of firing would be related to the mean firing rate as an inverse square root law; the maintained discharges of retinal ganglion cells deviate systematically from such a relationship. A more realistic relationship can be obtained if the integrate-and-fire mechanism is "leaky"; with this refinement, the integrate-and-fire model captures the essential features of the data. However, the model shows that the distribution of intervals is insensitive to that of the underlying variability. The leakage time constant, threshold, and distribution of the noise are confounded, rendering the model unspecifiable. Another aspect of variability is presented by the variance of responses to repeated discrete stimuli. The variance of response rate increases with the mean response amplitude; the nature of that relationship depends on the duration of the periods in which the response is sampled. These results have defied explanation. But if it is assumed that variability depends on mean rate in the way observed for maintained discharges, the variability of responses to abrupt changes in lighting can be predicted from the observed mean responses. The parameters that provide the best fits for the variability of responses also provide a reasonable fit to the variability of maintained discharges.

  18. Computer Model Locates Environmental Hazards

    NASA Technical Reports Server (NTRS)

    2008-01-01

    Catherine Huybrechts Burton founded San Francisco-based Endpoint Environmental (2E) LLC in 2005 while she was a student intern and project manager at Ames Research Center with NASA's DEVELOP program. The 2E team created the Tire Identification from Reflectance model, which algorithmically processes satellite images using turnkey technology to retain only the darkest parts of an image. This model allows 2E to locate piles of rubber tires, which often are stockpiled illegally and cause hazardous environmental conditions and fires.

  19. Programmer's manual for the fire safety evaluation system cost minimizer computer program

    NASA Astrophysics Data System (ADS)

    Chapman, R. E.; Hall, W. G.

    1983-07-01

    The fire safety evaluation system cost minimizer (FSESCM) computer program integrates engineering and economic considerations with a linear programming algorithm which permits the least-cost means of upgrading health care facilities to compliance with the Life Safety Code to be identified. A mathematical discussion of the application program is used to introduce the basic philosophy behind the FORTRAN program.

  20. Computational modelling of polymers

    NASA Technical Reports Server (NTRS)

    Celarier, Edward A.

    1991-01-01

    Polymeric materials and polymer/graphite composites show a very diverse range of material properties, many of which make them attractive candidates for a variety of high performance engineering applications. Their properties are ultimately determined largely by their chemical structure, and the conditions under which they are processed. It is the aim of computational chemistry to be able to simulate candidate polymers on a computer, and determine what their likely material properties will be. A number of commercially available software packages purport to predict the material properties of samples, given the chemical structures of their constituent molecules. One such system, Cerius, has been in use at LaRC. It is comprised of a number of modules, each of which performs a different kind of calculation on a molecule in the programs workspace. Particularly, interest is in evaluating the suitability of this program to aid in the study of microcrystalline polymeric materials. One of the first model systems examined was benzophenone. The results of this investigation are discussed.

  1. Fire risk in San Diego County, California: A weighted Bayesian model approach

    USGS Publications Warehouse

    Kolden, Crystal A.; Weigel, Timothy J.

    2007-01-01

    Fire risk models are widely utilized to mitigate wildfire hazards, but models are often based on expert opinions of less understood fire-ignition and spread processes. In this study, we used an empirically derived weights-of-evidence model to assess what factors produce fire ignitions east of San Diego, California. We created and validated a dynamic model of fire-ignition risk based on land characteristics and existing fire-ignition history data, and predicted ignition risk for a future urbanization scenario. We then combined our empirical ignition-risk model with a fuzzy fire behavior-risk model developed by wildfire experts to create a hybrid model of overall fire risk. We found that roads influence fire ignitions and that future growth will increase risk in new rural development areas. We conclude that empirically derived risk models and hybrid models offer an alternative method to assess current and future fire risk based on management actions.

  2. Fire danger and fire behavior modeling systems in Australia, Europe, and North America

    Treesearch

    Francis M. Fujioka; A. Malcolm Gill; Domingos X. Viegas; B. Mike Wotton

    2009-01-01

    Wildland fire occurrence and behavior are complex phenomena involving essentially fuel (vegetation), topography, and weather. Fire managers around the world use a variety of systems to track and predict fire danger and fire behavior, at spatial scales that span from local to global extents, and temporal scales ranging from minutes to seasons. The fire management...

  3. WILDLAND FIRE EMISSION MODELING FOR CMAQ: AN UPDATE

    EPA Science Inventory

    This paper summarizes recent efforts to improve the methods used for modeling wild land fire emissions both for retrospective modeling and real-time forecasting. These improvements focus on the temporal and spatial resolution of the activity data as well as the methods to estimat...

  4. FireStem2D – A Two-Dimensional Heat Transfer Model for Simulating Tree Stem Injury in Fires

    PubMed Central

    Chatziefstratiou, Efthalia K.; Bohrer, Gil; Bova, Anthony S.; Subramanian, Ravishankar; Frasson, Renato P. M.; Scherzer, Amy; Butler, Bret W.; Dickinson, Matthew B.

    2013-01-01

    FireStem2D, a software tool for predicting tree stem heating and injury in forest fires, is a physically-based, two-dimensional model of stem thermodynamics that results from heating at the bark surface. It builds on an earlier one-dimensional model (FireStem) and provides improved capabilities for predicting fire-induced mortality and injury before a fire occurs by resolving stem moisture loss, temperatures through the stem, degree of bark charring, and necrotic depth around the stem. We present the results of numerical parameterization and model evaluation experiments for FireStem2D that simulate laboratory stem-heating experiments of 52 tree sections from 25 trees. We also conducted a set of virtual sensitivity analysis experiments to test the effects of unevenness of heating around the stem and with aboveground height using data from two studies: a low-intensity surface fire and a more intense crown fire. The model allows for improved understanding and prediction of the effects of wildland fire on injury and mortality of trees of different species and sizes. PMID:23894599

  5. FireStem2D--a two-dimensional heat transfer model for simulating tree stem injury in fires.

    PubMed

    Chatziefstratiou, Efthalia K; Bohrer, Gil; Bova, Anthony S; Subramanian, Ravishankar; Frasson, Renato P M; Scherzer, Amy; Butler, Bret W; Dickinson, Matthew B

    2013-01-01

    FireStem2D, a software tool for predicting tree stem heating and injury in forest fires, is a physically-based, two-dimensional model of stem thermodynamics that results from heating at the bark surface. It builds on an earlier one-dimensional model (FireStem) and provides improved capabilities for predicting fire-induced mortality and injury before a fire occurs by resolving stem moisture loss, temperatures through the stem, degree of bark charring, and necrotic depth around the stem. We present the results of numerical parameterization and model evaluation experiments for FireStem2D that simulate laboratory stem-heating experiments of 52 tree sections from 25 trees. We also conducted a set of virtual sensitivity analysis experiments to test the effects of unevenness of heating around the stem and with aboveground height using data from two studies: a low-intensity surface fire and a more intense crown fire. The model allows for improved understanding and prediction of the effects of wildland fire on injury and mortality of trees of different species and sizes.

  6. Modelling wildland fire propagation by tracking random fronts

    NASA Astrophysics Data System (ADS)

    Pagnini, G.; Mentrelli, A.

    2014-08-01

    Wildland fire propagation is studied in the literature by two alternative approaches, namely the reaction-diffusion equation and the level-set method. These two approaches are considered alternatives to each other because the solution of the reaction-diffusion equation is generally a continuous smooth function that has an exponential decay, and it is not zero in an infinite domain, while the level-set method, which is a front tracking technique, generates a sharp function that is not zero inside a compact domain. However, these two approaches can indeed be considered complementary and reconciled. Turbulent hot-air transport and fire spotting are phenomena with a random nature and they are extremely important in wildland fire propagation. Consequently, the fire front gets a random character, too; hence, a tracking method for random fronts is needed. In particular, the level-set contour is randomised here according to the probability density function of the interface particle displacement. Actually, when the level-set method is developed for tracking a front interface with a random motion, the resulting averaged process emerges to be governed by an evolution equation of the reaction-diffusion type. In this reconciled approach, the rate of spread of the fire keeps the same key and characterising role that is typical of the level-set approach. The resulting model emerges to be suitable for simulating effects due to turbulent convection, such as fire flank and backing fire, the faster fire spread being because of the actions by hot-air pre-heating and by ember landing, and also due to the fire overcoming a fire-break zone, which is a case not resolved by models based on the level-set method. Moreover, from the proposed formulation, a correction follows for the formula of the rate of spread which is due to the mean jump length of firebrands in the downwind direction for the leeward sector of the fireline contour. The presented study constitutes a proof of concept, and it

  7. Applicability of an integrated plume rise model for the dispersion from wild-land fires

    NASA Astrophysics Data System (ADS)

    Kukkonen, J.; Nikmo, J.; Sofiev, M.; Riikonen, K.; Petäjä, T.; Virkkula, A.; Levula, J.; Schobesberger, S.; Webber, D. M.

    2014-11-01

    We have presented an overview of a mathematical model, BUOYANT, that was originally designed for the evaluation of the dispersion of buoyant plumes originated from major warehouse fires. The model addresses the variations of the cross-plume integrated properties of a buoyant plume in the presence of a vertically varying atmosphere. The model also includes a treatment for a rising buoyant plume interacting with an inversion layer. We have compared the model predictions with the data of two prescribed wild-land fire experiments. For the SCAR-C experiment in Quinault (US) in 1994, the predicted vertical extents of the plume at maximum plume rise were between 500 and 800 m and between 200 and 700 m, using two alternative meteorological data sets. The corresponding observed injection heights of the aerosol particles measured using an airborne lidar (light detection and ranging) ranged from 250 to 600 m. For the prescribed burning experiment in Hyytiälä (Finland) in 2009, the model predictions were compared with plume elevations and diameters, determined based on particulate matter number concentration measurements onboard an aeroplane. However, the agreement between modelled and measured results substantially depends on how the properties of the source term are evaluated, especially regarding the convective heat fluxes from the fire. The results demonstrate that in field experiments on wild-land fires, there are substantial uncertainties in estimating both (i) the source terms for the atmospheric dispersion computations and (ii) the relevant vertical meteorological profiles.

  8. Models of optical quantum computing

    NASA Astrophysics Data System (ADS)

    Krovi, Hari

    2017-03-01

    I review some work on models of quantum computing, optical implementations of these models, as well as the associated computational power. In particular, we discuss the circuit model and cluster state implementations using quantum optics with various encodings such as dual rail encoding, Gottesman-Kitaev-Preskill encoding, and coherent state encoding. Then we discuss intermediate models of optical computing such as boson sampling and its variants. Finally, we review some recent work in optical implementations of adiabatic quantum computing and analog optical computing. We also provide a brief description of the relevant aspects from complexity theory needed to understand the results surveyed.

  9. Fire severity estimated from remote sensing data to evaluate the Coupled Atmosphere-Wildland Fire-Environment (CAWFE) model

    NASA Astrophysics Data System (ADS)

    Oliva, P.; Coen, J.; Schroeder, W.

    2013-12-01

    Fire severity defined as the degree of damage originated from fire on soils and vegetation immediately after the fire, is affected by weather conditions (i.e. wind, air humidity), terrain characteristics (i.e. slope, aspect) and fuel properties (i.e. tree density, fuel moisture content). In this study we evaluated the relationships between fire severity estimated from Earth Observing Advance Land Imager (EO-ALI) images and the heat fluxes produced by the Coupled Atmosphere-Wildland Fire-Environment (CAWFE) model (Coen 2013). We present the results for a large fire occurred in New Mexico in June 2012 which burned 44,330 acres. The EO-ALI sensor (30 m spatial resolution) has nine spectral bands, six of them were designed to mimic Landsat bands and the three additional bands cover 443, 867.5 and 1250 nm. We used a physically-based approach to estimate fire severity developed by De Santis et al. (2009). This method classifies the satellite image into Geophysical Composite burned index (GeoCBI) values, which represent the fire severity within the fire-affected area, using radiative transfer model simulated spectra as reference. This method has been used to characterize fire severity levels using Landsat images and validated with field data (R2 > 0.85). Based on those results we expected a better performance of EO-ALI images due to its improved spectral resolution. On the other hand, CAWFE is composed of two parts: a numerical weather prediction model and a fire behavior module that represents the growth of a wildland fire in response to factors such as wind, terrain, and fuels, and includes the fire's impact on the atmosphere. To perform the evaluation we selected a stratified random sample by fire severity level. The values of maximum heat flux (sensible, latent), and total heat flux showed a higher correlation with the higher levels of fire severity (GeoCBI: 2.8-3) than with the medium levels of fire severity (GeoCBI: 2.3-2.8). However, the total heat flux proved to

  10. Aerosol dispersion and coagulation from a coal-fired power plant: a three dimensional numerical model

    SciTech Connect

    Buckholtz, H.T.; Biermann, A.H.

    1980-01-01

    A computational model to simulate the dispersion and coagulation of aerosols emitted from coal-fired power plants was constructed. In modeling the dispersion of the aerosol, turbulent diffusion and wind-driven advection are treated by a finite-difference method. Molecular coagulation is incorporated in the model to follow shifts in the particle-size distribution. Particulate coagulation is mathematically described by Timiskii's equation. The relevent semi-empirical work of Smirnov is incorporated in the model to provide for the coagultion constant. Input for the model is a bimodal, particle-size distribution measured at an operating coal-fired power plant. Simulations indicate that dispersion competes against coagulation mechanisms to maintain the bimodal shaped distribution for 32 km. Turbulence and particle settling tend to enchance coagulation effects. The size-dependent spatial segregation of particles within the plume is predicted.

  11. Motoneuron model of self-sustained firing after spinal cord injury

    PubMed Central

    Kurian, Mini; Jung, Ranu

    2016-01-01

    Under many conditions spinal motoneurons produce plateau potentials, resulting in self-sustained firing and providing a mechanism for translating short-lasting synaptic inputs into long-lasting motor output. During the acute-stage of spinal cord injury (SCI), the endogenous ability to generate plateaus is lost; however, during the chronic-stage of SCI, plateau potentials reappear with prolonged self-sustained firing that has been implicated in the development of spasticity. In this work, we extend previous modeling studies to systematically investigate the mechanisms underlying the generation of plateau potentials in motoneurons, including the influences of specific ionic currents, the morphological characteristics of the soma and dendrite, and the interactions between persistent inward currents and synaptic input. In particular, the goal of these computational studies is to explore the possible interactions between morphological and electrophysiological changes that occur after incomplete SCI. Model results predict that some of the morphological changes generally associated with the chronic-stage for some types of spinal cord injuries can cause a decrease in self-sustained firing. This and other computational results presented here suggest that the observed increases in self-sustained firing following some types of SCI may occur mainly due to changes in membrane conductances and changes in synaptic activity, particularly changes in the strength and timing of inhibition. PMID:21526348

  12. Using neutral models to identify constraints on low-severity fire regimes.

    Treesearch

    Donald McKenzie; Amy E. Hessl; Lara-Karena B. Kellogg

    2006-01-01

    Climate, topography, fuel loadings, and human activities all affect spatial and temporal patterns of fire occurrence. Because fire is modeled as a stochastic process, for which each fire history is only one realization, a simulation approach is necessary to understand baseline variability, thereby identifying constraints, or forcing functions, that affect fire regimes...

  13. Workshop on Computational Turbulence Modeling

    NASA Technical Reports Server (NTRS)

    1993-01-01

    This document contains presentations given at Workshop on Computational Turbulence Modeling held 15-16 Sep. 1993. The purpose of the meeting was to discuss the current status and future development of turbulence modeling in computational fluid dynamics for aerospace propulsion systems. Papers cover the following topics: turbulence modeling activities at the Center for Modeling of Turbulence and Transition (CMOTT); heat transfer and turbomachinery flow physics; aerothermochemistry and computational methods for space systems; computational fluid dynamics and the k-epsilon turbulence model; propulsion systems; and inlet, duct, and nozzle flow.

  14. Modelling Odor Decoding in the Antennal Lobe by Combining Sequential Firing Rate Models with Bayesian Inference

    PubMed Central

    Cuevas Rivera, Dario; Bitzer, Sebastian; Kiebel, Stefan J.

    2015-01-01

    The olfactory information that is received by the insect brain is encoded in the form of spatiotemporal patterns in the projection neurons of the antennal lobe. These dense and overlapping patterns are transformed into a sparse code in Kenyon cells in the mushroom body. Although it is clear that this sparse code is the basis for rapid categorization of odors, it is yet unclear how the sparse code in Kenyon cells is computed and what information it represents. Here we show that this computation can be modeled by sequential firing rate patterns using Lotka-Volterra equations and Bayesian online inference. This new model can be understood as an ‘intelligent coincidence detector’, which robustly and dynamically encodes the presence of specific odor features. We found that the model is able to qualitatively reproduce experimentally observed activity in both the projection neurons and the Kenyon cells. In particular, the model explains mechanistically how sparse activity in the Kenyon cells arises from the dense code in the projection neurons. The odor classification performance of the model proved to be robust against noise and time jitter in the observed input sequences. As in recent experimental results, we found that recognition of an odor happened very early during stimulus presentation in the model. Critically, by using the model, we found surprising but simple computational explanations for several experimental phenomena. PMID:26451888

  15. Modeling post-fire water erosion mitigation strategies

    NASA Astrophysics Data System (ADS)

    Rulli, M. C.; Offeddu, L.; Santini, M.

    2013-06-01

    Severe wildfires are often followed by significant increase in runoff and erosion, due to vegetation damage and changes in physical and chemical soil properties. Peak flows and sediment yields can increase up to two orders of magnitude, becoming dangerous for human lives and the ecosystem, especially in the wildland-urban interface. Watershed post-fire rehabilitation measures are usually used to mitigate the effects of fire on runoff and erosion, by protecting soil from splash and shear stress detachment and enhancing its infiltration capacity. Modeling post-fire erosion and erosion mitigation strategies can be useful in selecting the effectiveness of a rehabilitation method. In this paper a distributed model based on the Revised Universal Soil Loss Equation (RUSLE), properly parameterized for a Mediterranean basin located in Sardinia, is used to determine soil losses for six different scenarios describing both natural and post-fire basin condition, the last also accounting for the single and combined effect of different erosion mitigation measures. Fire effect on vegetation and soil properties have been mimed by changing soil drainage capacity and organic matter content, and RUSLE factors related to soil cover and protection measures. Model results, validated using measured data on erosion rates from the literature and in situ field campaigns, show the effect of the analyzed rehabilitation treatments in reducing the amount of soil losses with the peculiar characteristics of the spatial distribution of such changes. In particular, the mulching treatment substantially decreases erosion both in its mean value (-75%) and in the spatially distribution of the erosion levels over the burned area . On the contrary, the breaking up of the hydrophobic layer decreases post-fire mean soil losses of about the 14%, although it strongly influences the spatial distribution of the erosion levels.

  16. Measurement strategy and analytic model to determine firing pin force

    NASA Astrophysics Data System (ADS)

    Lesenciuc, Ioan; Suciu, Cornel

    2016-12-01

    As illustrated in literature, ballistics is a branch of theoretical mechanics, which studies the construction and working principles of firearms and ammunition, their effects, as well as the motions of projectiles and bullets1. Criminalistics identification, as part of judiciary identification represents an activity aimed at finding common traits of different objects, objectives, phenomena and beings, but more importantly, traits that differentiate each of them from similar ones2-4. In judicial ballistics, in the case of rifled firearms it is relatively simple for experts to identify the used weapon from traces left on the projectile, as the rifling of the barrel leaves imprints on the bullet, which remain approximately identical even after the respective weapon is fired 100 times with the same barrel. However, in the case of smoothbore firearms, their identification becomes much more complicated. As the firing cap suffers alterations from being hit by the firing pin, determination of the force generated during impact creates the premises for determining the type of firearm used to shoot the respective cartridge. The present paper proposes a simple impact model that can be used to evaluate the force generated by the firing pin during its impact with the firing cap. The present research clearly showed that each rifle, by the combination of the three investigated parameters (impact force maximum value, its variation diagram, and impact time) leave a unique trace. Application of such a method in ballistics can create the perspectives for formulating clear conclusions that eliminate possible judicial errors in this field.

  17. Observed and Modeled Prescribed Fire Emissions and Transport

    NASA Astrophysics Data System (ADS)

    Strenfel, S. J.; Clements, C. B.; Freedman, F. R.; Hiers, J. K.

    2009-12-01

    Prescribed fire is a frequently utilized land-management tool in the Southeastern US. It is estimated > one million acres are consumed annually by prescribed fire in Georgia (Lee et al., 2005) and eight million acres in southern states combined (Wade and Lundsford, 1998). In situ data were obtained from three summer (wet season) and winter (dry) fires with a 10 m instrumented tower at the Joseph W. Jones Ecological Research Center at Ichauway. Fuel consumption and fire-return interval for each burn was ~ 2 tons acre-1 and 2 years, respectively. Emission factors for PM2.5, BC, CO and CO2 were derived using a carbon mass-balance method. Summer (winter) PM2.5, CO, and CO2 emission factors were 13.7 ± 4.1 g kg-1 (8.6 ± 2.0), 25.9 ± 5.2 (16.1 ± 2.2), 1796 ± 30 (1852 ± 13), respectively. Calculated emission factors were compared to emission factors derived from Consume 3.0 model runs. Dry-season winter fires yielded the highest combustion efficiencies. Pollutant dispersion and transport was evaluated with AERMOD utilizing the emission factors and observed meteorological conditions, and results generally agree with in situ measurements made downwind of each burn unit.

  18. BEHAVE: fire behavior prediction and fuel modeling system - BURN subsystem, Part 2

    Treesearch

    Patricia L. Andrews; Carolyn H. Chase

    1989-01-01

    This is the third publication describing the BEHAVE system of computer programs for predicting behavior of wildland fires. This publication adds the following predictive capabilities: distance firebrands are lofted ahead of a wind-driven surface fire, probabilities of firebrands igniting spot fires, scorch height of trees, and percentage of tree mortality. The system...

  19. Modeling of Ceiling Fire Spread and Thermal Radiation.

    DTIC Science & Technology

    1981-10-01

    AD-A1O? 590 FACTORY MUTUAL RESEARCH CORP NORWOOD MASS F/G 21/2 MODELING OF CEILING FIRE SPREAD AND THERMAL RADIATION(U) OCT 81 R L ALPERT,,M K...CEILING FIRE SPREAD AND THERMAL RADIATION R . L. Alpert M. K. Mathews A. T. Modak *1 FEDERAL AVIATION ADMINISTRATION TECHNICAL CENTER Atlantic City Airport...Technical Report Documentation Poeg 1. R ,rt No. 2. Governmont Accession No. 3. Recipient’s Cotlog No. DOT/FAA/CT-81-70 4. Title and Subtitle S. Report

  20. Model of spills and fires from LNG and oil tankers.

    PubMed

    Fay, J A

    2003-01-31

    A comprehensive model for predicting the dynamics of spills from LNG and oil product tankers is constructed from fluid mechanics principles and empirical properties of oil and LNG spills on water. The analysis utilizes the significant tanker hold and discharge flow area dimensions to specify the cargo liquid outflow history and the ensuing pool characteristics, including the establishment of a pool fire. The pool fire area, duration, and heat release rate are determined as functions of the tanker cargo variables. Examples of an LNG and gasoline spill show that for likely discharge flow areas these spills may be regarded as instantaneous, simplifying the evaluation of risk consequences.

  1. Validating the Malheur model for predicting ponderosa pine post-fire mortality using 24 fires in the Pacific Northwest, USA

    Treesearch

    Walter G. Thies; Douglas J. Westlind

    2012-01-01

    Fires, whether intentionally or accidentally set, commonly occur in western interior forests of the US. Following fire, managers need the ability to predict mortality of individual trees based on easily observed characteristics. Previously, a two-factor model using crown scorch and bole scorch proportions was developed with data from 3415 trees for predicting the...

  2. Modeling of integrated environmental control systems for coal-fired power plants. Technical progress report, [period ending December 31, 1987

    SciTech Connect

    Rubin, E.S.

    1988-01-01

    This is the first quarterly report of DOE/PETC Contract No. DE-AC22-87PC79864, entitled, ``Modeling of Integrated Environmental Control Systems for Coal-Fired Power Plants.`` Refining, creating, and documenting of computer models concerning coal/flue gas cleaning and desulfurization are discussed. (VC)

  3. COMPUTER MODELS/EPANET

    EPA Science Inventory

    Pipe network flow analysis was among the first civil engineering applications programmed for solution on the early commercial mainframe computers in the 1960s. Since that time, advancements in analytical techniques and computing power have enabled us to solve systems with tens o...

  4. COMPUTER MODELS/EPANET

    EPA Science Inventory

    Pipe network flow analysis was among the first civil engineering applications programmed for solution on the early commercial mainframe computers in the 1960s. Since that time, advancements in analytical techniques and computing power have enabled us to solve systems with tens o...

  5. 8. Photocopy of photograph showing model display NIKE Hercules firing ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. Photocopy of photograph showing model display NIKE Hercules firing battery, ARADCOM Argus pg. 11, from Institute for Military History, Carlisle Barracks, Carlisle, PA, March 1, 1961 - NIKE Missile Battery PR-79, East Windsor Road south of State Route 101, Foster, Providence County, RI

  6. Targeting forest management through fire and erosion modeling

    Treesearch

    William J. Elliot; Mary Ellen Miller; Nic Enstice

    2016-01-01

    Forests deliver a number of important ecosystem services, including clean water. When forests are disturbed by wildfire, the timing, quantity and quality of runoff are altered. A modelling study was conducted in a forested watershed in California, USA, to determine the risk of wildfire, and the potential post-fire sediment delivery from ~4-ha hillslope polygons within...

  7. Validation of a probabilistic post-fire erosion model

    Treesearch

    Pete Robichaud; William J. Elliot; Sarah A. Lewis; Mary Ellen Miller

    2016-01-01

    Post-fire increases of runoff and erosion often occur and land managers need tools to be able to project the increased risk. The Erosion Risk Management Tool (ERMiT) uses the Water Erosion Prediction Project (WEPP) model as the underlying processor. ERMiT predicts the probability of a given amount of hillslope sediment delivery from a single rainfall or...

  8. Combining fire and erosion modeling to target forest management activities

    Treesearch

    William J. Elliot; Mary Ellen Miller; Nic Enstice

    2015-01-01

    Forests deliver a number of important ecosystem services including clean water. When forests are disturbed by wildfire, the timing, quantity and quality of runoff are altered. A modeling study was carried out in a forested watershed in California to determine the risk of wildfire, and the potential post-fire sediment delivery from approximately 6-ha hillslope polygons...

  9. A mathematical model for predicting fire spread in wildland fuels

    Treesearch

    Richard C. Rothermel

    1972-01-01

    A mathematical fire model for predicting rate of spread and intensity that is applicable to a wide range of wildland fuels and environment is presented. Methods of incorporating mixtures of fuel sizes are introduced by weighting input parameters by surface area. The input parameters do not require a prior knowledge of the burning characteristics of the fuel.

  10. (EDMUNDS, WA) WILDLAND FIRE EMISSIONS MODELING: INTEGRATING BLUESKY AND SMOKE

    EPA Science Inventory

    This presentation is a status update of the BlueSky emissions modeling system. BlueSky-EM has been coupled with the Sparse Matrix Operational Kernel Emissions (SMOKE) system, and is now available as a tool for estimating emissions from wildland fires

  11. A mathematical model of a large open fire

    NASA Technical Reports Server (NTRS)

    Harsha, P. T.; Bragg, W. N.; Edelman, R. B.

    1981-01-01

    A mathematical model capable of predicting the detailed characteristics of large, liquid fuel, axisymmetric, pool fires is described. The predicted characteristics include spatial distributions of flame gas velocity, soot concentration and chemical specie concentrations including carbon monoxide, carbon dioxide, water, unreacted oxygen, unreacted fuel and nitrogen. Comparisons of the predictions with experimental values are also given.

  12. Supporting FIRE-suppression strategies combining fire spread MODelling and SATellite data in an operational context in Portugal: the FIRE-MODSAT project

    NASA Astrophysics Data System (ADS)

    Sá, Ana C. L.; Benali, Akli; Pinto, Renata M. S.; Pereira, José M. C.; Trigo, Ricardo M.; DaCamara, Carlos C.

    2014-05-01

    Large wildfires are infrequent but account for the most severe environmental, ecological and socio-economic impacts. In recent years Portugal has suffered the impact of major heat waves that fuelled records of burnt area exceeding 400.000ha and 300.000ha in 2003 and 2005, respectively. According to the latest IPCC reports, the frequency and amplitude of summer heat waves over Iberia will very likely increase in the future. Therefore, most climate change studies point to an increase in the number and extent of wildfires. Thus, an increase in both wildfire impacts and fire suppression difficulties is expected. The spread of large wildfires results from a complex interaction between topography, meteorology and fuel properties. Wildfire spread models (e.g. FARSITE) are commonly used to simulate fire growth and behaviour and are an essential tool to understand their main drivers. Additionally, satellite active-fire data have been used to monitor the occurrence, extent, and spread of wildfires. Both satellite data and fire spread models provide different types of information about the spatial and temporal distribution of large wildfires and can potentially be used to support strategic decisions regarding fire suppression resource allocation. However, they have not been combined in a manner that fully exploits their potential and minimizes their limitations. A knowledge gap still exists in understanding how to minimize the impacts of large wildfires, leading to the following research question: What can we learn from past large wildfires in order to mitigate future fire impacts? FIRE-MODSAT is a one-year funded project by the Portuguese Foundation for the Science and Technology (FCT) that is founded on this research question, with the main goal of improving our understanding on the interactions between fire spread and its environmental drivers, to support fire management decisions in an operational context and generate valuable information to improve the efficiency of the

  13. Computational model for interfaces

    NASA Astrophysics Data System (ADS)

    Glimm, J.; McBryan, O. A.

    1985-06-01

    Decompositions of the plane into disjoint components separated by curves occur frequently. We describe a package of subroutines which provides facilities for defining, building and modifying such decompositions and for efficiently solving various point and area location problems. Beyond the point that the specification of this package may be useful to others, we reach the broader conclusion that well designed data structures and support routines allow the use of more conceptual or nonnumerical portions of mathematics in the computational process, thereby extending greatly the potential scope of the use of computers in scientific problem solving. Ideas from conceptual mathematics, symbolic computation and computer science can be utilized within the framework of scientific computing and have an important role to play in that area.

  14. Understanding the dynamic climate-fire-ecosystem interactions using the CESM: Fire model development and implications for decadal climate variability

    NASA Astrophysics Data System (ADS)

    Zou, Y.; Wang, Y.; Ke, Z.; Tian, H.; Yang, J.; Liu, Y.

    2016-12-01

    Wildfire plays a critical role in modulating regional to global climate through disturbances on multiple weather, climate and ecosystem processes, while wildfire itself is strongly affected by climate and ecosystems. The climate-fire-ecosystem interactions are complex and not well understood. We developed a region-specific fire model with ecosystem feedbacks in the CESM that provides the modeling capability of understanding these interactions. We conducted two sets of decadal simulations for present (2000-2010) and future (2040-2050) scenarios. Our implementation of the fire model, which includes dynamic plume rise calculations, can reproduce the observations of fire counts and burned area by MODIS fire products and the latest version of Global Fire Emissions Database (GFED4.1s) and those of plum rise height by MISR using either reanalysis meteorological data or CESM simulations in 2000-2010. We conducted model simulations to examine how drought, wildfire, and ecosystems interact, leading to a positive feedback in the regional climate. We further investigate how the feedbacks change in 2040-2050 under the RCP4.5 scenario. These results demonstrate the latest progress of global fire modeling development in climate model studies.

  15. The impact of fires in the UK Met Office's Unified Model and the INFERNO interactive fire scheme

    NASA Astrophysics Data System (ADS)

    Mangeon, S.

    2015-12-01

    Forest fires are a key interaction between the land and the atmosphere. Yet this interaction is often omitted from Earth System Models. We will present the efforts carried out within the UK Met Office: for both its Unified Model (UM8.4) and land surface model (JULES). These efforts have focused on diagnosing fire occurrence and impact on composition. We will present the schemes used for diagnostic fire weather indices, and INFERNO (INteractive Fires and Emissions algoRithm for Natural envirOnments). INFERNO follows a reduced complexity approach and is intended for decadal to centennial scale climate simulations and assessment models for policy making. The scheme uses temperature, relative humidity, precipitation and soil moisture to simulate fuel flammability; once combined with ignitions, INFERNO diagnoses burnt area. Using JULES' carbon scheme, burnt area leads to fire emissions which are inputs to the model's chemistry and aerosol scheme (UKCA). We will show the coupled model performance in capturing burnt area and fire emissions and investigate the role of fires on atmospheric composition interannual variability (in particular CO, and aerosols).

  16. Simulating the effects of fire and climate change on northern Rocky Mountain landscapes using the ecological process model FIRE-BGC

    SciTech Connect

    Keane, R.E.; Ryan, K.; Running, S.W.

    1995-12-31

    A mechanistic successional model, FIRE-BGC (a FIRE BioGeoChemical succession model), has been developed to investigate the role of fire and climate on long-term landscape dynamics in northern Rocky Mountain coniferous forests. This FIRE-BGC application explicitly simulates fire behavior and effects on landscape characteristics. Predictions of evapotranspiration are contrasted with and without fire over 200 years of simulation for the McDonald Drainage, Glacier National Park under current climate conditions are provided as an example of the potential of FIRE-BGC.

  17. ClassyFire: automated chemical classification with a comprehensive, computable taxonomy.

    PubMed

    Djoumbou Feunang, Yannick; Eisner, Roman; Knox, Craig; Chepelev, Leonid; Hastings, Janna; Owen, Gareth; Fahy, Eoin; Steinbeck, Christoph; Subramanian, Shankar; Bolton, Evan; Greiner, Russell; Wishart, David S

    2016-01-01

    Scientists have long been driven by the desire to describe, organize, classify, and compare objects using taxonomies and/or ontologies. In contrast to biology, geology, and many other scientific disciplines, the world of chemistry still lacks a standardized chemical ontology or taxonomy. Several attempts at chemical classification have been made; but they have mostly been limited to either manual, or semi-automated proof-of-principle applications. This is regrettable as comprehensive chemical classification and description tools could not only improve our understanding of chemistry but also improve the linkage between chemistry and many other fields. For instance, the chemical classification of a compound could help predict its metabolic fate in humans, its druggability or potential hazards associated with it, among others. However, the sheer number (tens of millions of compounds) and complexity of chemical structures is such that any manual classification effort would prove to be near impossible. We have developed a comprehensive, flexible, and computable, purely structure-based chemical taxonomy (ChemOnt), along with a computer program (ClassyFire) that uses only chemical structures and structural features to automatically assign all known chemical compounds to a taxonomy consisting of >4800 different categories. This new chemical taxonomy consists of up to 11 different levels (Kingdom, SuperClass, Class, SubClass, etc.) with each of the categories defined by unambiguous, computable structural rules. Furthermore each category is named using a consensus-based nomenclature and described (in English) based on the characteristic common structural properties of the compounds it contains. The ClassyFire webserver is freely accessible at http://classyfire.wishartlab.com/. Moreover, a Ruby API version is available at https://bitbucket.org/wishartlab/classyfire_api, which provides programmatic access to the ClassyFire server and database. ClassyFire has been used to

  18. Random Sampling with Interspike-Intervals of the Exponential Integrate and Fire Neuron: A Computational Interpretation of UP-States.

    PubMed

    Steimer, Andreas; Schindler, Kaspar

    2015-01-01

    Oscillations between high and low values of the membrane potential (UP and DOWN states respectively) are an ubiquitous feature of cortical neurons during slow wave sleep and anesthesia. Nevertheless, a surprisingly small number of quantitative studies have been conducted only that deal with this phenomenon's implications for computation. Here we present a novel theory that explains on a detailed mathematical level the computational benefits of UP states. The theory is based on random sampling by means of interspike intervals (ISIs) of the exponential integrate and fire (EIF) model neuron, such that each spike is considered a sample, whose analog value corresponds to the spike's preceding ISI. As we show, the EIF's exponential sodium current, that kicks in when balancing a noisy membrane potential around values close to the firing threshold, leads to a particularly simple, approximative relationship between the neuron's ISI distribution and input current. Approximation quality depends on the frequency spectrum of the current and is improved upon increasing the voltage baseline towards threshold. Thus, the conceptually simpler leaky integrate and fire neuron that is missing such an additional current boost performs consistently worse than the EIF and does not improve when voltage baseline is increased. For the EIF in contrast, the presented mechanism is particularly effective in the high-conductance regime, which is a hallmark feature of UP-states. Our theoretical results are confirmed by accompanying simulations, which were conducted for input currents of varying spectral composition. Moreover, we provide analytical estimations of the range of ISI distributions the EIF neuron can sample from at a given approximation level. Such samples may be considered by any algorithmic procedure that is based on random sampling, such as Markov Chain Monte Carlo or message-passing methods. Finally, we explain how spike-based random sampling relates to existing computational

  19. Assessing the outstanding 2003 fire events in Portugal with a Regional Climate Model

    NASA Astrophysics Data System (ADS)

    Trigo, Ricardo; Jerez, Sonia; Camara, Carlos; Montávez, Juan Pedro

    2013-04-01

    The heatwave that struck western Iberia in the early days of August 2003 was characterized by record high values of both maximum (47.3°C) and minimum (30.6°c) temperatures in Portugal, associated with extremely low humidity levels and relatively intense wind speed (Trigo et al., 2006). These conditions triggered the most devastating sequence of large fires ever registered in Portugal. The estimated total burnt area was about 450.000 ha, including 280.000 ha of forest (Pereira et al., 2011). The outstanding total burnt area value corresponds to roughly 5% of the Portuguese territory, and represents approximately twice the previous maximum observed in 1998 (~220.000 ha), and about four times the long-term average observed between 1980 and 2004. Here we characterise this unusual episode using meteorological fields obtained from both observations and a regional climate model. In this work we use the longest (49-years) high-resolution regional climate simulation available driven by reanalysis data spanning from 1959 to 2007 and covering the entire Iberian Peninsula. This long run was obtained using the MM5 model with a spatial resolution of 10 km. Using this high spatial and temporal resolution we have computed the Canadian Fire Weather Index (FWI) System to produce hourly values of fire risk. The FWI System consists of six components that account for the effects of fuel moisture and wind on fire behaviour (van Wagner, 1987). We show the temporal evolution of high resolution patterns for several fire related variables during the most important days for triggering new fires (the first week of August 2003). Besides the absolute value of Tmax, Tmin, wind (speed and direction), relative humidity and FWI we also evaluate the corresponding anomalies of these fields, obtained after removing the long-term smoothed daily climatology. Pereira M.G., Malamude B.D., Trigo R.M., Alves P.I. (2011) "The History and Characteristics of the 1980-2005 Portuguese Rural Fire Database

  20. 29 CFR Appendix A to Subpart P to... - Model Fire Safety Plan (Non-Mandatory)

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 7 2011-07-01 2011-07-01 false Model Fire Safety Plan (Non-Mandatory) A Appendix A to Subpart P to Part 1915 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH...—Model Fire Safety Plan (Non-Mandatory) Model Fire Safety Plan Note: This appendix is non-mandatory and...

  1. Simulating effects of fire on northern Rocky Mountain landscapes with the ecological process model FIRE-BGC.

    PubMed

    Keane, R E; Ryan, K C; Running, S W

    1996-03-01

    A mechanistic, biogeochemical succession model, FIRE-BGC, was used to investigate the role of fire on long-term landscape dynamics in northern Rocky Mountain coniferous forests of Glacier National Park, Montana, USA. FIRE-BGC is an individual-tree model-created by merging the gap-phase process-based model FIRESUM with the mechanistic ecosystem biogeochemical model FOREST-BGC-that has mixed spatial and temporal resolution in its simulation architecture. Ecological processes that act at a landscape level, such as fire and seed dispersal, are simulated annually from stand and topographic information. Stand-level processes, such as tree establishment, growth and mortality, organic matter accumulation and decomposition, and undergrowth plant dynamics are simulated both daily and annually. Tree growth is mechanistically modeled based on the ecosystem process approach of FOREST-BGC where carbon is fixed daily by forest canopy photosynthesis at the stand level. Carbon allocated to the tree stem at the end of the year generates the corresponding diameter and height growth. The model also explicitly simulates fire behavior and effects on landscape characteristics. We simulated the effects of fire on ecosystem characteristics of net primary productivity, evapotranspiration, standing crop biomass, nitrogen cycling and leaf area index over 200 years for the 50,000-ha McDonald Drainage in Glacier National Park. Results show increases in net primary productivity and available nitrogen when fires are included in the simulation. Standing crop biomass and evapotranspiration decrease under a fire regime. Shade-intolerant species dominate the landscape when fires are excluded. Model tree increment predictions compared well with field data.

  2. Mathematical Modeling and Computational Thinking

    ERIC Educational Resources Information Center

    Sanford, John F.; Naidu, Jaideep T.

    2017-01-01

    The paper argues that mathematical modeling is the essence of computational thinking. Learning a computer language is a valuable assistance in learning logical thinking but of less assistance when learning problem-solving skills. The paper is third in a series and presents some examples of mathematical modeling using spreadsheets at an advanced…

  3. An oscillatory interference model of grid cell firing

    PubMed Central

    Burgess, N; Barry, C; O'Keefe, J

    2009-01-01

    We expand upon our proposal that the oscillatory interference mechanism proposed for the phase precession effect in place cells underlies the grid-like firing pattern of dorsomedial entorhinal grid cells (O'Keefe & Burgess, 2005). The original 1-dimensional interference model is generalized to an appropriate 2-dimensional mechanism. Specifically, dendritic subunits of layer II medial entorhinal stellate cells provide multiple linear interference patterns along different directions, with their product determining the firing of the cell. Connection of appropriate speed- and direction- dependent inputs onto dendritic subunits could result from an unsupervised learning rule which maximizes post-synaptic firing (e.g. competitive learning). These inputs cause the intrinsic oscillation of subunit membrane potential to increase above theta frequency by an amount proportional to the animal's speed of running in the ‘preferred’ direction. The phase difference between this oscillation and a somatic input at theta-frequency essentially integrates velocity so that the interference of the two oscillations reflects distance traveled in the preferred direction. The overall grid pattern is maintained in environmental location by phase reset of the grid cell by place cells receiving sensory input from the environment, and environmental boundaries in particular. We also outline possible variations on the basic model, including the generation of grid-like firing via the interaction of multiple cells rather than via multiple dendritic subunits. Predictions of the interference model are given for the frequency composition of EEG power spectra and temporal autocorrelograms of grid cell firing as functions of the speed and direction of running and the novelty of the environment. PMID:17598147

  4. The use of computer models to predict temperature and smoke movement in high bay spaces

    NASA Technical Reports Server (NTRS)

    Notarianni, Kathy A.; Davis, William D.

    1993-01-01

    The Building and Fire Research Laboratory (BFRL) was given the opportunity to make measurements during fire calibration tests of the heat detection system in an aircraft hangar with a nominal 30.4 (100 ft) ceiling height near Dallas, TX. Fire gas temperatures resulting from an approximately 8250 kW isopropyl alcohol pool fire were measured above the fire and along the ceiling. The results of the experiments were then compared to predictions from the computer fire models DETACT-QS, FPETOOL, and LAVENT. In section A of the analysis conducted, DETACT-QS AND FPETOOL significantly underpredicted the gas temperature. LAVENT at the position below the ceiling corresponding to maximum temperature and velocity provided better agreement with the data. For large spaces, hot gas transport time and an improved fire plume dynamics model should be incorporated into the computer fire model activation routines. A computational fluid dynamics (CFD) model, HARWELL FLOW3D, was then used to model the hot gas movement in the space. Reasonable agreement was found between the temperatures predicted from the CFD calculations and the temperatures measured in the aircraft hangar. In section B, an existing NASA high bay space was modeled using the CFD model. The NASA space was a clean room, 27.4 m (90 ft) high with forced horizontal laminar flow. The purpose of this analysis is to determine how the existing fire detection devices would respond to various size fires in the space. The analysis was conducted for 32 MW, 400 kW, and 40 kW fires.

  5. The use of computer models to predict temperature and smoke movement in high bay spaces

    NASA Astrophysics Data System (ADS)

    Notarianni, Kathy A.; Davis, William D.

    1993-12-01

    The Building and Fire Research Laboratory (BFRL) was given the opportunity to make measurements during fire calibration tests of the heat detection system in an aircraft hangar with a nominal 30.4 (100 ft) ceiling height near Dallas, TX. Fire gas temperatures resulting from an approximately 8250 kW isopropyl alcohol pool fire were measured above the fire and along the ceiling. The results of the experiments were then compared to predictions from the computer fire models DETACT-QS, FPETOOL, and LAVENT. In section A of the analysis conducted, DETACT-QS AND FPETOOL significantly underpredicted the gas temperature. LAVENT at the position below the ceiling corresponding to maximum temperature and velocity provided better agreement with the data. For large spaces, hot gas transport time and an improved fire plume dynamics model should be incorporated into the computer fire model activation routines. A computational fluid dynamics (CFD) model, HARWELL FLOW3D, was then used to model the hot gas movement in the space. Reasonable agreement was found between the temperatures predicted from the CFD calculations and the temperatures measured in the aircraft hangar. In section B, an existing NASA high bay space was modeled using the CFD model. The NASA space was a clean room, 27.4 m (90 ft) high with forced horizontal laminar flow. The purpose of this analysis is to determine how the existing fire detection devices would respond to various size fires in the space. The analysis was conducted for 32 MW, 400 kW, and 40 kW fires.

  6. Computation models of discourse

    SciTech Connect

    Brady, M.; Berwick, R.C.

    1983-01-01

    This book presents papers on artificial intelligence and natural language. Topics considered include recognizing intentions from natural language utterances, cooperative responses from a portable natural language database query system, natural language generation as a computational problem, focusing in the comprehension of definite anaphora, and factors in forming discourse-dependent descriptions.

  7. Computational investigation of carbon-in-ash levels for a wall-fired boiler after low-NOx combustion modifications

    SciTech Connect

    Davis, K.A.; Eddings, E.G.; Heap, M.P.; Facchiano, A.; Hardman, R.R.

    1998-12-31

    Many coal-fired boilers retrofitted with low NOX firing systems are experiencing significant operational difficulties due primarily to (1) increased carbon in the fly ash or (2) increased water wall wastage. This paper presents the results of a computational investigation of a wall-fired boiler that has recently been retrofitted with low NOx burners and overfire air. The focus of this paper is the effect of the retrofit on unburned carbon/NOx and the potential for applying operational and design modifications to minimize unburned carbon without adversely impacting NOx emissions. Although the magnitude of an increase in unburned carbon after a low NOx retrofit is system and coal dependent, it is often the case that reduction in emissions of nitrogen oxides is accompanied by a corresponding increase in the amount of unburned carbon in fly ash. Since low NOX firing systems increase the residence time of coal/char particles in a fuel rich environment, it might be expected that there is insufficient time under high temperature, oxidizing conditions to ensure complete carbon oxidation in a low NOx firing system. A relatively straight forward consideration of the effect of temperature and oxygen concentration on coal particle pyrolysis/oxidation can be used to provide a qualitative understanding of this effect. However, the complex flow patterns and highly nonlinear physical and chemical phenomena in a boiler make it difficult to predict carbon-in-ash (c-i-a) levels without the use of advanced computational tools. The sensitivity of c-i-a to burnout is pointed out in a figure for a coal with 10% ash. Although c-i-a changes slowly for low burnout, it changes very rapidly at the extent of burnout typical of a boiler. When the extent of burnout drops only slightly, from 99.5 to 99 percent for example, the c-i-a doubles, from 4 to 8%, which in many situations would be unacceptable. The importance of fuel efficiency and ash disposal/recycle emphasizes the need for

  8. Jet fire consequence modeling for high-pressure gas pipelines

    NASA Astrophysics Data System (ADS)

    Coccorullo, Ivano; Russo, Paola

    2016-12-01

    A simple and reliable approach for sizing the hazard area potentially affected by a jet fire as consequence of the failure of high-pressure pipeline is proposed. A release rate model, taking pipeline operation properties and source release properties into account, is coupled with SLAB dispersion model and point source radiation model to calculate the hazard distance. The hazard distance is set beyond the distance at which a low chance of fatality can occur to people exposed and a wooden structure is not expected to burn due to radiation heat of jet fire. The comparison between three gases with different physico-chemical properties (i.e. natural gas, hydrogen, ethylene) is shown. The influence of pipeline operating parameters, such as: pressure, pipeline diameter and length, hole size, on the hazard area for the three gases is evaluated. Finally, a simple correlation is proposed for calculating the hazard distance as function of these parameters.

  9. Computational Models for Neuromuscular Function

    PubMed Central

    Valero-Cuevas, Francisco J.; Hoffmann, Heiko; Kurse, Manish U.; Kutch, Jason J.; Theodorou, Evangelos A.

    2011-01-01

    Computational models of the neuromuscular system hold the potential to allow us to reach a deeper understanding of neuromuscular function and clinical rehabilitation by complementing experimentation. By serving as a means to distill and explore specific hypotheses, computational models emerge from prior experimental data and motivate future experimental work. Here we review computational tools used to understand neuromuscular function including musculoskeletal modeling, machine learning, control theory, and statistical model analysis. We conclude that these tools, when used in combination, have the potential to further our understanding of neuromuscular function by serving as a rigorous means to test scientific hypotheses in ways that complement and leverage experimental data. PMID:21687779

  10. Cogeneration Technology Alternatives Study (CTAS). Volume 6: Computer data. Part 2: Residual-fired nocogeneration process boiler

    NASA Technical Reports Server (NTRS)

    Knightly, W. F.

    1980-01-01

    Computer generated data on the performance of the cogeneration energy conversion system are presented. Performance parameters included fuel consumption and savings, capital costs, economics, and emissions of residual fired process boilers.

  11. EARTH, WIND AND FIRE: BUILDING METEOROLOGICALLY-SENSITIVE BIOGENIC AND WILDLAND FIRE EMISSION ESTIMATES FOR AIR QUALITY MODELS

    EPA Science Inventory

    Emission estimates are important for ensuring the accuracy of atmospheric chemical transport models. Estimates of biogenic and wildland fire emissions, because of their sensitivity to meteorological conditions, need to be carefully constructed and closely linked with a meteorolo...

  12. EARTH, WIND AND FIRE: BUILDING METEOROLOGICALLY-SENSITIVE BIOGENIC AND WILDLAND FIRE EMISSION ESTIMATES FOR AIR QUALITY MODELS

    EPA Science Inventory

    Emission estimates are important for ensuring the accuracy of atmospheric chemical transport models. Estimates of biogenic and wildland fire emissions, because of their sensitivity to meteorological conditions, need to be carefully constructed and closely linked with a meteorolo...

  13. On Fire regime modelling using satellite TM time series

    NASA Astrophysics Data System (ADS)

    Oddi, F.; . Ghermandi, L.; Lanorte, A.; Lasaponara, R.

    2009-04-01

    Wildfires can cause an environment deterioration modifying vegetation dynamics because they have the capacity of changing vegetation diversity and physiognomy. In semiarid regions, like the northwestern Patagonia, fire disturbance is also important because it could impact on the potential productivity of the ecosystem. There is reduction plant biomass and with that reducing the animal carrying capacity and/or the forest site quality with negative economics implications. Therefore knowledge of the fires regime in a region is of great importance to understand and predict the responses of vegetation and its possible effect on the regional economy. Studies of this type at a landscape level can be addressed using GIS tools. Satellite imagery allows detect burned areas and through a temporary analysis can be determined to fire regime and detecting changes at landscape scale. The study area of work is located on the east of the city of Bariloche including the San Ramon Ranch (22,000 ha) and its environs in the ecotone formed by the sub Antarctic forest and the patagonian steppe. We worked with multiespectral Landsat TM images and Landsat ETM + 30m spatial resolution obtained at different times. For the spatial analysis we used the software Erdas Imagine 9.0 and ArcView 3.3. A discrimination of vegetation types has made and was determined areas affected by fires in different years. We determined the level of change on vegetation induced by fire. In the future the use of high spatial resolution images combined with higher spectral resolution will allows distinguish burned areas with greater precision on study area. Also the use of digital terrain models derived from satellite imagery associated with climatic variables will allows model the relationship between them and the dynamics of vegetation.

  14. Fire disturbance and vegetation dynamics : analysis and models

    NASA Astrophysics Data System (ADS)

    Thonicke, Kirsten

    2003-04-01

    Studies of the role of disturbance in vegetation or ecosystems showed that disturbances are an essential and intrinsic element of ecosystems that contribute substantially to ecosystem health, to structural diversity of ecosystems and to nutrient cycling at the local as well as global level. Fire as a grassland, bush or forest fire is a special disturbance agent, since it is caused by biotic as well abiotic environmental factors. Fire affects biogeochemical cycles and plays an important role in atmospheric chemistry by releasing climate-sensitive trace gases and aerosols, and thus in the global carbon cycle by releasing approximately 3.9 Gt C p.a. through biomass burning. A combined model to describe effects and feedbacks between fire and vegetation became relevant as changes in fire regimes due to land use and land management were observed and the global dimension of biomass burnt as an important carbon flux to the atmosphere, its influence on atmospheric chemistry and climate as well as vegetation dynamics were emphasized. The existing modelling approaches would not allow these investigations. As a consequence, an optimal set of variables that best describes fire occurrence, fire spread and its effects in ecosystems had to be defined, which can simulate observed fire regimes and help to analyse interactions between fire and vegetation dynamics as well as to allude to the reasons behind changing fire regimes. Especially, dynamic links between vegetation, climate and fire processes are required to analyse dynamic feedbacks and effects of changes of single environmental factors. This led us to the point, where new fire models had to be developed that would allow the investigations, mentioned above, and could help to improve our understanding of the role of fire in global ecology. In conclusion of the thesis, one can state that moisture conditions, its persistence over time and fuel load are the important components that describe global fire pattern. If time series of

  15. HESFIRE: a global fire model to explore the role of anthropogenic and weather drivers

    DOE PAGES

    Le Page, Yannick LB; Morton, Douglas; Bond-Lamberty, Benjamin; ...

    2015-02-13

    Vegetation fires are a major driver of ecosystem dynamics and greenhouse gas emissions. Anticipating potential changes in fire activity and their impacts relies first on a realistic model of fire activity (e.g., fire incidence and interannual variability) and second on a model accounting for fire impacts (e.g., mortality and emissions). In this paper, we focus on our understanding of fire activity and describe a new fire model, HESFIRE (Human–Earth System FIRE), which integrates the influence of weather, vegetation characteristics, and human activities on fires in a stand-alone framework. It was developed with a particular emphasis on allowing fires to spreadmore » over consecutive days given their major contribution to burned areas in many ecosystems. A subset of the model parameters was calibrated through an optimization procedure using observation data to enhance our knowledge of regional drivers of fire activity and improve the performance of the model on a global scale. Modeled fire activity showed reasonable agreement with observations of burned area, fire seasonality, and interannual variability in many regions, including for spatial and temporal domains not included in the optimization procedure. Significant discrepancies are investigated, most notably regarding fires in boreal regions and in xeric ecosystems and also fire size distribution. The sensitivity of fire activity to model parameters is analyzed to explore the dominance of specific drivers across regions and ecosystems. The characteristics of HESFIRE and the outcome of its evaluation provide insights into the influence of anthropogenic activities and weather, and their interactions, on fire activity.« less

  16. Computer-Aided Geometry Modeling

    NASA Technical Reports Server (NTRS)

    Shoosmith, J. N. (Compiler); Fulton, R. E. (Compiler)

    1984-01-01

    Techniques in computer-aided geometry modeling and their application are addressed. Mathematical modeling, solid geometry models, management of geometric data, development of geometry standards, and interactive and graphic procedures are discussed. The applications include aeronautical and aerospace structures design, fluid flow modeling, and gas turbine design.

  17. Applicability of an integrated plume rise model for the dispersion from wild-land fires

    NASA Astrophysics Data System (ADS)

    Kukkonen, J.; Nikmo, J.; Sofiev, M.; Riikonen, K.; Petäjä, T.; Virkkula, A.; Levula, J.; Schobesberger, S.; Webber, D. M.

    2014-01-01

    We have presented an overview of a mathematical model, BUOYANT, that was originally designed for the evaluation of the dispersion of buoyant plumes originated from major warehouse fires. The model addresses the variations of the cross-plume integrated properties of a buoyant plume in the presence of a vertically varying atmosphere. The model also includes a treatment for a rising buoyant plume interacting with an inversion layer. We have compared the model predictions with the data of two prescribed wild-land fire experiments. For the SCAR-C experiment in Quinault (US) in 1994, the predicted vertical extents of the plume at maximum plume rise were between 500-800 m and 200-700 m, using two alternative meteorological datasets. The corresponding observed injection heights of the aerosol particles measured using an airborne LIDAR (LIght Detection And Ranging) ranged from 250 and 600 m. For the prescribed burning experiment in Hyytiälä (Finland) in 2009, the model predictions were compared with plume elevations and diameters, determined based on particulate matter number concentration measurements on board an aeroplane. The agreement of modelled and measured results was good, provided that one assumes the measured maximum convective heat fluxes as input data for the model. The results demonstrate that in field experiments on wild-land fires, there are substantial uncertainties in estimating both (i) the source terms for the atmospheric dispersion computations, and (ii) the relevant vertical meteorological profiles. The results provide more confidence that cross-plume integrated mathematical models, such as the BUOYANT model, can be used to fairly good accuracy for evaluating the dispersion from major wild-land fires.

  18. Practical approximation method for firing-rate models of coupled neural networks with correlated inputs

    NASA Astrophysics Data System (ADS)

    Barreiro, Andrea K.; Ly, Cheng

    2017-08-01

    Rapid experimental advances now enable simultaneous electrophysiological recording of neural activity at single-cell resolution across large regions of the nervous system. Models of this neural network activity will necessarily increase in size and complexity, thus increasing the computational cost of simulating them and the challenge of analyzing them. Here we present a method to approximate the activity and firing statistics of a general firing rate network model (of the Wilson-Cowan type) subject to noisy correlated background inputs. The method requires solving a system of transcendental equations and is fast compared to Monte Carlo simulations of coupled stochastic differential equations. We implement the method with several examples of coupled neural networks and show that the results are quantitatively accurate even with moderate coupling strengths and an appreciable amount of heterogeneity in many parameters. This work should be useful for investigating how various neural attributes qualitatively affect the spiking statistics of coupled neural networks.

  19. First-order fire effects models for land Management: Overview and issues

    Treesearch

    Elizabeth D. Reinhardt; Matthew B. Dickinson

    2010-01-01

    We give an overview of the science application process at work in supporting fire management. First-order fire effects models, such as those discussed in accompanying papers, are the building blocks of software systems designed for application to landscapes over time scales from days to centuries. Fire effects may be modeled using empirical, rule based, or process...

  20. A chance-constrained programming model to allocate wildfire initial attack resources for a fire season

    Treesearch

    Yu Wei; Michael Bevers; Erin Belval; Benjamin Bird

    2015-01-01

    This research developed a chance-constrained two-stage stochastic programming model to support wildfire initial attack resource acquisition and location on a planning unit for a fire season. Fire growth constraints account for the interaction between fire perimeter growth and construction to prevent overestimation of resource requirements. We used this model to examine...

  1. A new method for the analysis of fire spread modeling errors

    Treesearch

    Francis M. Fujioka

    2002-01-01

    Fire spread models have a long history, and their use will continue to grow as they evolve from a research tool to an operational tool. This paper describes a new method to analyse two-dimensional fire spread modeling errors, particularly to quantify the uncertainties of fire spread predictions. Measures of error are defined from the respective spread distances of...

  2. The FireBGCv2 landscape fire and succession model: a research simulation platform for exploring fire and vegetation dynamics

    Treesearch

    Robert E. Keane; Rachel A. Loehman; Lisa M. Holsinger

    2011-01-01

    Fire management faces important emergent issues in the coming years such as climate change, fire exclusion impacts, and wildland-urban development, so new, innovative means are needed to address these challenges. Field studies, while preferable and reliable, will be problematic because of the large time and space scales involved. Therefore, landscape simulation...

  3. Modeling hydrogen-cyanide absorption in fires

    NASA Technical Reports Server (NTRS)

    Cagliostro, D. E.; Islas, A.

    1981-01-01

    A mathematical model is developed for predicting blood concentrations of cyanide as functions of exposure time to constant levels of cyanide in the atmosphere. A toxic gas (which may form as a result of decomposition of combustion materials used in transportation vehicles) is breathed into the alveolar space and transferred from the alveolar space to the blood by a first-order process, dependent on the concentration of the toxicant in the alveolar space. The model predicts that blood cyanide levels are more sensitive to the breathing cycle than to blood circulation. A model estimate of the relative effects of CO and HCN atmospheres, generated in an experimental chamber with an epoxy polymer, shows that toxic effects of cyanide occur long before those of carbon monoxide.

  4. Beyond "fire temperatures": calibrating thermocouple probes and modeling their response to surface fires in hardwood fuels

    Treesearch

    Anthony S. Bova; Matthew B. Dickinson

    2008-01-01

    The maximum temperatures of thermocouples, temperature-sensitive paints, and calorimeters exposed to flames in wildland fires are often called "fire temperatures" but are determined as much by the properties and deployment of the measurement devices as by the fires themselves. Rather than report device temperatures that are not generally comparable among...

  5. Understanding global fire dynamics by classifying and comparing spatial models of vegetation and fire

    Treesearch

    Robert E. Keane; Geoffrey J. Cary; Ian D. Davies; Michael D. Flannigan; Robert H. Gardner; Sandra Lavorel; James M. Lenihan; Chao Li; T. Scott Rupp

    2007-01-01

    Wildland fire is a major disturbance in most ecosystems worldwide (Crutzen and Goldammer 1993). The interaction of fire with climate and vegetation over long time spans, often referred to as the fire regime (Agee 1993; Clark 1993; Swetnam and Baisan 1996; Swetnam 1997), has major effects on dominant vegetation, ecosystem carbon budget, and biodiversity (Gardner et aL...

  6. Modeling impacts of fire severity on successional trajectories and future fire behavior in Alaskan boreal forests

    Treesearch

    Jill F. Johnstone; T. Scott Rupp; Mark Olson; David. Verbyla

    2011-01-01

    Much of the boreal forest in western North America and Alaska experiences frequent, stand-replacing wildfires. Secondary succession after fire initiates most forest stands and variations in fire characteristics can have strong effects on pathways of succession. Variations in surface fire severity that influence whether regenerating forests are dominated by coniferous...

  7. Two-target game model of an air combat with fire-and-forget all-aspect missiles

    NASA Technical Reports Server (NTRS)

    Davidovitz, A.; Shinar, J.

    1989-01-01

    An air combat duel between similar aggressive fighter aircraft, both equipped with the same type of guided missiles, is formulated as a two-target differential game using the dynamic model of the game of two identical cars. Each of the identical target sets represents the effective firing envelope of an all-aspect fire-and-forget air-to-air missile. The firing range limits depend on the target aspect angle and are approximated by analytical functions. The maximum range, computed by taking into account the optimal missile avoidance maneuver of the target, determines the no-escape firing envelope. The solution consists of the decomposition of the game space into four regions: the respective winning zones of the two opponents, the draw zone, and the region where the game terminates by a mutual kill. The solution provides a new insight for future air combat analysis.

  8. Two-target game model of an air combat with fire-and-forget all-aspect missiles

    NASA Technical Reports Server (NTRS)

    Davidovitz, A.; Shinar, J.

    1989-01-01

    An air combat duel between similar aggressive fighter aircraft, both equipped with the same type of guided missiles, is formulated as a two-target differential game using the dynamic model of the game of two identical cars. Each of the identical target sets represents the effective firing envelope of an all-aspect fire-and-forget air-to-air missile. The firing range limits depend on the target aspect angle and are approximated by analytical functions. The maximum range, computed by taking into account the optimal missile avoidance maneuver of the target, determines the no-escape firing envelope. The solution consists of the decomposition of the game space into four regions: the respective winning zones of the two opponents, the draw zone, and the region where the game terminates by a mutual kill. The solution provides a new insight for future air combat analysis.

  9. Computational models of syntactic acquisition.

    PubMed

    Yang, Charles

    2012-03-01

    The computational approach to syntactic acquisition can be fruitfully pursued by integrating results and perspectives from computer science, linguistics, and developmental psychology. In this article, we first review some key results in computational learning theory and their implications for language acquisition. We then turn to examine specific learning models, some of which exploit distributional information in the input while others rely on a constrained space of hypotheses, yet both approaches share a common set of characteristics to overcome the learning problem. We conclude with a discussion of how computational models connects with the empirical study of child grammar, making the case for computationally tractable, psychologically plausible and developmentally realistic models of acquisition. WIREs Cogn Sci 2012, 3:205-213. doi: 10.1002/wcs.1154 For further resources related to this article, please visit the WIREs website.

  10. Fire risk analysis: general conceptual framework for describing models.

    PubMed

    Hall, J R; Sekizawa, A

    1991-02-01

    A general conceptual framework has been developed as an aid to discussions of alternative approaches to fire risk analysis. The purpose is to show how each alternative seeks to address a few common concerns. Basic concepts and key elements--notably scenario structures, appropriate probability functions, and security and outcome measures--are defined and discussed, as are types of modeling approaches. A number of diverse examples are then presented using the framework to illustrate its value in making comparisons.

  11. Considerations in Scale-Modeling of Large Urban Fires

    DTIC Science & Technology

    1984-11-15

    is inconsequential and that all molecular transport processes are unimportant). The nondimensional parameters to be preserved between the model and...fuel bed. Parker, Corlett and B. T. Lee [!3] also come to a similar conclusion based * on the following two points. First, in large fires, molecular ...to USDA Forest Service, Prepared by Instituto Nacional "de Tecnica Aeroespacial, Madrid, Spain, (May, 1967). "" 57. S.L. Lee and G.M. Hellman

  12. A process-based fire parameterization of intermediate complexity in a Dynamic Global Vegetation Model

    NASA Astrophysics Data System (ADS)

    Li, F.; Zeng, X. D.; Levis, S.

    2012-07-01

    A process-based fire parameterization of intermediate complexity has been developed for global simulations in the framework of a Dynamic Global Vegetation Model (DGVM) in an Earth System Model (ESM). Burned area in a grid cell is estimated by the product of fire counts and average burned area of a fire. The scheme comprises three parts: fire occurrence, fire spread, and fire impact. In the fire occurrence part, fire counts rather than fire occurrence probability are calculated in order to capture the observed high burned area fraction in areas of high fire frequency and realize parameter calibration based on MODIS fire counts product. In the fire spread part, post-fire region of a fire is assumed to be elliptical in shape. Mathematical properties of ellipses and some mathematical derivations are applied to improve the equation and assumptions of an existing fire spread parameterization. In the fire impact part, trace gas and aerosol emissions due to biomass burning are estimated, which offers an interface with atmospheric chemistry and aerosol models in ESMs. In addition, flexible time-step length makes the new fire parameterization easily applied to various DGVMs. Global performance of the new fire parameterization is assessed by using an improved version of the Community Land Model version 3 with the Dynamic Global Vegetation Model (CLM-DGVM). Simulations are compared against the latest satellite-based Global Fire Emission Database version 3 (GFED3) for 1997-2004. Results show that simulated global totals and spatial patterns of burned area and fire carbon emissions, regional totals and spreads of burned area, global annual burned area fractions for various vegetation types, and interannual variability of burned area are reasonable, and closer to GFED3 than CLM-DGVM simulations with the commonly used Glob-FIRM fire parameterization and the old fire module of CLM-DGVM. Furthermore, average error of simulated trace gas and aerosol emissions due to biomass burning

  13. Modelling post-fire vegetation recovery in Portugal

    NASA Astrophysics Data System (ADS)

    Bastos, A.; Gouveia, C.; Dacamara, C. C.; Trigo, R. M.

    2011-05-01

    Wildfires in Mediterranean Europe have been increasing in number and extension over the last decades and constitute one of the major disturbances of these ecosystems. Portugal is the country with more burnt area in the last decade and the years of 2003 and 2005 were particularly devastating, the total burned areas of 425 000 and 338 000 ha being several times higher than the corresponding average. The year of 2005 further coincided with one of the most severe droughts since early 20th century. Due to different responses of vegetation to diverse fire regimes and to the complexity of landscape structures, fires have complex effects on vegetation recovery. Remote sensing has revealed to be a powerful tool in studying vegetation dynamics and in monitoring post-fire vegetation recovery, which is crucial to land-management and to prevent erosion. The main goals of the present work are (i) to assess the accuracy of a vegetation recovery model previously developed by the authors; (ii) to assess the model's performance, namely its sensitivity to initial conditions, to the temporal length of the input dataset and to missing data; (iii) to study vegetation recovery over two selected areas that were affected by two large wildfire events in the fire seasons of 2003 and 2005, respectively. The study relies on monthly values of NDVI over 11 yr (1998-2009), at 1 × 1 km spatial resolution, as obtained by the VEGETATION instrument. According to results from sensitivity analysis, the model is robust and able to provide good estimations of recovery times of vegetation when the regeneration process is regular, even when missing data is present. In what respect to the two selected burnt scars, results indicate that fire damage is a determinant factor of regeneration, as less damaged vegetation recovers more rapidly, which is mainly justified by the high coverage of Pinus Pinaster over the area, and by the fact that coniferous forests tend to recover slower than transitional woodland

  14. Modelling post-fire vegetation recovery in Portugal

    NASA Astrophysics Data System (ADS)

    Bastos, A.; Gouveia, C. M.; Dacamara, C. C.; Trigo, R. M.

    2011-12-01

    Wildfires in Mediterranean Europe have been increasing in number and extension over the last decades and constitute one of the major disturbances of these ecosystems. Portugal is the country with more burnt area in the last decade and the years of 2003 and 2005 were particularly devastating, the total burned areas of 425 000 and 338 000 ha being several times higher than the corresponding average. The year of 2005 further coincided with one of the most severe droughts since early 20th century. Due to different responses of vegetation to diverse fire regimes and to the complexity of landscape structures, fires have complex effects on vegetation recovery. Remote sensing has revealed to be a powerful tool in studying vegetation dynamics and in monitoring post-fire vegetation recovery, which is crucial to land-management and to prevent erosion. The main goals of the present work are (i) to assess the accuracy of a vegetation recovery model previously developed by the authors; (ii) to assess the model's performance, namely its sensitivity to initial conditions, to the temporal length of the input dataset and to missing data; (iii) to study vegetation recovery over two selected areas that were affected by two large wildfire events in the fire seasons of 2003 and 2005, respectively. The study relies on monthly values of NDVI over 11 years (1998-2009), at 1 km × 1 km spatial resolution, as obtained by the VEGETATION instrument. According to results from sensitivity analysis, the model is robust and able to provide good estimations of recovery times of vegetation when the regeneration process is regular, even when missing data is present. In respect to the two selected burnt scars, results indicate that fire damage is a determinant factor of regeneration, as less damaged vegetation recovers more rapidly, which is mainly justified by the high coverage of Pinus pinaster over the area, and by the fact that coniferous forests tend to recover slower than transitional woodland

  15. Computational Modeling of Space Physiology

    NASA Technical Reports Server (NTRS)

    Lewandowski, Beth E.; Griffin, Devon W.

    2016-01-01

    The Digital Astronaut Project (DAP), within NASAs Human Research Program, develops and implements computational modeling for use in the mitigation of human health and performance risks associated with long duration spaceflight. Over the past decade, DAP developed models to provide insights into space flight related changes to the central nervous system, cardiovascular system and the musculoskeletal system. Examples of the models and their applications include biomechanical models applied to advanced exercise device development, bone fracture risk quantification for mission planning, accident investigation, bone health standards development, and occupant protection. The International Space Station (ISS), in its role as a testing ground for long duration spaceflight, has been an important platform for obtaining human spaceflight data. DAP has used preflight, in-flight and post-flight data from short and long duration astronauts for computational model development and validation. Examples include preflight and post-flight bone mineral density data, muscle cross-sectional area, and muscle strength measurements. Results from computational modeling supplement space physiology research by informing experimental design. Using these computational models, DAP personnel can easily identify both important factors associated with a phenomenon and areas where data are lacking. This presentation will provide examples of DAP computational models, the data used in model development and validation, and applications of the model.

  16. toolkit computational mesh conceptual model.

    SciTech Connect

    Baur, David G.; Edwards, Harold Carter; Cochran, William K.; Williams, Alan B.; Sjaardema, Gregory D.

    2010-03-01

    The Sierra Toolkit computational mesh is a software library intended to support massively parallel multi-physics computations on dynamically changing unstructured meshes. This domain of intended use is inherently complex due to distributed memory parallelism, parallel scalability, heterogeneity of physics, heterogeneous discretization of an unstructured mesh, and runtime adaptation of the mesh. Management of this inherent complexity begins with a conceptual analysis and modeling of this domain of intended use; i.e., development of a domain model. The Sierra Toolkit computational mesh software library is designed and implemented based upon this domain model. Software developers using, maintaining, or extending the Sierra Toolkit computational mesh library must be familiar with the concepts/domain model presented in this report.

  17. Fast Computation of CMH Model

    NASA Technical Reports Server (NTRS)

    Patel, Umesh D.; DellaTorre, Edward; Day, John H. (Technical Monitor)

    2001-01-01

    A fast differential equation approach for the DOK model has been extented to the CMH model. Also, a cobweb technique for calculating the CMH model is also presented. The two techniques are contrasted from the point of view of flexibility and computation time.

  18. Research and application of the heat transfer model of Coalfield fire

    NASA Astrophysics Data System (ADS)

    Weiguo, Dong; Zhongyong, Cai; Chunxia, Xu

    2010-05-01

    Coalfield fire is a common disaster of human. The status of coalfield fire in the world, the ways and character of coalfield fire heat transfer, were introduced in this paper on the purpose of quantifying the coal burnt in the Coalfield fire, the greenhouse gas released and the exploitation of CDM methodology. The heat of coalfield fire was released into the atmosphere by four ways: radiation, convection, carried by concentrated emission gas and dispersing emission gas. Based on the conservative principle, the heat transfer model of Coalfield fire was established. Based on the energy conservation law and the element conservation principle, the quantity of coal burned and CO2 released of the Coalfield fire can be calculated through the quantity of heat transferred. Applying this model into the practical calculation of the south fire zone of Shuixi Gou Coalfield Fire, Jimsar County, Xinjiang, P.R. China, the result show that the burnt coal of this fire zone is about 41.6 kiloton per year; the quantity of CO2 released is about 106.3 kiloton per year. The establishment of the heat transfer model of Coalfield fire has very important signification for quantifying the evaluation of the influence of coalfield fire to environment and resource, also for exploiting coalfield fire extinguishing CDM methodology.

  19. Modeling the performance of coated LPG tanks engulfed in fires.

    PubMed

    Landucci, Gabriele; Molag, Menso; Cozzani, Valerio

    2009-12-15

    The improvement of passive fire protection of storage vessels is a key factor to enhance safety among the LPG distribution chain. A thermal and mechanical model based on finite elements simulations was developed to assess the behaviour of full size tanks used for LPG storage and transportation in fire engulfment scenarios. The model was validated by experimental results. A specific analysis of the performance of four different reference coating materials was then carried out, also defining specific key performance indicators (KPIs) to assess design safety margins in near-miss simulations. The results confirmed the wide influence of coating application on the expected vessel time to failure due to fire engulfment. A quite different performance of the alternative coating materials was evidenced. General correlations were developed among the vessel time to failure and the effective coating thickness in full engulfment scenarios, providing a preliminary assessment of the coating thickness required to prevent tank rupture for a given time lapse. The KPIs defined allowed the assessment of the available safety margins in the reference scenarios analyzed and of the robustness of thermal protection design.

  20. Incorporating anthropogenic influences into fire probability models: Effects of development and climate change on fire activity in California

    NASA Astrophysics Data System (ADS)

    Mann, M.; Moritz, M.; Batllori, E.; Waller, E.; Krawchuk, M.; Berck, P.

    2014-12-01

    The costly interactions between humans and natural fire regimes throughout California demonstrate the need to understand the uncertainties surrounding wildfire, especially in the face of a changing climate and expanding human communities. Although a number of statistical and process-based wildfire models exist for California, there is enormous uncertainty about the location and number of future fires. Models estimate an increase in fire occurrence between nine and fifty-three percent by the end of the century. Our goal is to assess the role of uncertainty in climate and anthropogenic influences on the state's fire regime from 2000-2050. We develop an empirical model that integrates novel information about the distribution and characteristics of future plant communities without assuming a particular distribution, and improve on previous efforts by integrating dynamic estimates of population density at each forecast time step. Historically, we find that anthropogenic influences account for up to fifty percent of the total fire count, and that further housing development will incite or suppress additional fires according to their intensity. We also find that the total area burned is likely to increase but at a slower than historical rate. Previous findings of substantially increased numbers of fires may be tied to the assumption of static fuel loadings, and the use of proxy variables not relevant to plant community distributions. We also find considerable agreement between GFDL and PCM model A2 runs, with decreasing fire counts expected only in areas of coastal influence below San Francisco and above Los Angeles. Due to potential shifts in rainfall patterns, substantial uncertainty remains for the semiarid deserts of the inland south. The broad shifts of wildfire between California's climatic regions forecast in this study point to dramatic shifts in the pressures plant and human communities will face by midcentury. The information provided by this study reduces the

  1. Predicting post-fire tree mortality for 14 conifers in the Pacific Northwest, USA: Model evaluation, development, and thresholds

    Treesearch

    Lindsay M. Grayson; Robert A. Progar; Sharon M. Hood

    2017-01-01

    Fire is a driving force in the North American landscape and predicting post-fire tree mortality is vital to land management. Post-fire tree mortality can have substantial economic and social impacts, and natural resource managers need reliable predictive methods to anticipate potential mortality following fire events. Current fire mortality models are limited to a few...

  2. Using a stochastic model and cross-scale analysis to evaluate controls on historical low-severity fire regimes

    Treesearch

    Maureen C. Kennedy; Donald. McKenzie

    2010-01-01

    Fire-scarred trees provide a deep temporal record of historical fire activity, but identifying the mechanisms therein that controlled landscape fire patterns is not straightforward. We use a spatially correlated metric for fire co-occurrence between pairs of trees (the Sørensen distance variogram), with output from a neutral model for fire history, to infer the...

  3. Mediterranean maquis fuel model development and mapping to support fire modeling

    NASA Astrophysics Data System (ADS)

    Bacciu, V.; Arca, B.; Pellizzaro, G.; Salis, M.; Ventura, A.; Spano, D.; Duce, P.

    2009-04-01

    Fuel load data and fuel model maps represent a critical issue for fire spread and behaviour modeling. The availability of accurate input data at different spatial and temporal scales can allow detailed analysis and predictions of fire hazard and fire effects across a landscape. Fuel model data are used in spatially explicit fire growth models to attain fire behaviour information for fuel management in prescribed fires, fire management applications, firefighters training, smoke emissions, etc. However, fuel type characteristics are difficult to be parameterized due to their complexity and variability: live and dead materials with different size contribute in different ways to the fire spread and behaviour. In the last decades, a strong help was provided by the use of remote sensing imagery at high spatial and spectral resolution. Such techniques are able to capture fine scale fuel distributions for accurate fire growth projections. Several attempts carried out in Europe were devoted to fuel classification and map characterization. In Italy, fuel load estimation and fuel model definition are still critical issues to be addressed due to the lack of detailed information. In this perspective, the aim of the present work was to propose an integrated approach based on field data collection, fuel model development and fuel model mapping to provide fuel models for the Mediterranean maquis associations. Field data needed for the development of fuel models were collected using destructive and non destructive measurements in experimental plots located in Northern Sardinia (Italy). Statistical tests were used to identify the main fuel types that were classified into four custom fuel models. Subsequently, a supervised classification by the Maximum Likelihood algorithm was applied on IKONOS images to identify and map the different types of maquis vegetation. The correspondent fuel model was then associated to each vegetation type to obtain the fuel model map. The results show the

  4. Modelling the propagation of smoke from a tanker fire in a built-up area.

    PubMed

    Brzozowska, Lucyna

    2014-02-15

    The paper presents the application of a Lagrangian particle model to problems connected with safety in road transport. Numerical simulations were performed for a hypothetical case of smoke emission from a tanker fire in a built-up area. Propagation of smoke was analysed for three wind directions. A diagnostic model was used to determine the air velocity field, whereas the dispersion of pollutants was analysed by means of a Lagrangian particle model (Brzozowska, 2013). The Idrisi Andes geographic information system was used to provide data on landforms and on their aerodynamic roughness. The presented results of computations and their analysis exemplify a possible application of the Lagrangian particle model: evaluation of mean (averaged over time) concentrations of pollutants and their distribution in the considered area (especially important due to the protection of people, animals and plants) and simulation of the propagation of harmful compounds in time as well as performing computations for cases of the potential effects of road incidents.

  5. Computer simulation study of the relationship between the profile of excitatory postsynaptic potential and stimulus-correlated motoneuron firing.

    PubMed

    Piotrkiewicz, Maria; Kudina, Lydia; Jakubiec, Michal

    2009-03-01

    This paper shows the results of computer simulation of changes in motoneuron (MN) firing evoked by a repetitively applied synaptic volley that consists of a single excitatory postsynaptic potential (EPSP). Spike trains produced by the threshold-crossing MN model were analyzed as experimental results. Various output functions were applied for analysis; the most useful was a peristimulus time histogram, a special modification of a raster plot and a peristimulus time frequencygram (PSTF). It has been shown that all functions complement each other in distinguishing between the genuine results evoked by the excitatory volley and the secondary results of the EPSP-evoked synchronization. The EPSP rising edge was best reproduced by the PSTF. However, whereas the EPSP rise time could be estimated quite accurately, especially for high EPSP amplitudes at high MN firing rates, the EPSP amplitude estimate was also influenced by factors unrelated to the synaptic volley, such as the afterhyperpolarization duration of the MN or the amplitude of synaptic noise, which cannot be directly assessed in human experiments. Thus, the attempts to scale any estimate of the EPSP amplitude in millivolts appear to be useless. The decaying phase of the EPSP cannot be reproduced accurately by any of the functions. For the short EPSPs, it is extinguished by the generation of an action potential and a subsequent decrease in the MN excitability. For longer EPSPs, it is inseparable from the secondary effects of synchronization. Thus, the methods aimed at extracting information about long-lasting and complex postsynaptic potentials from stimulus-correlated MN firing, should be refined, and the theoretical considerations checked in computer simulations.

  6. FOCUS: a fire management planning system -- final report

    Treesearch

    Frederick W. Bratten; James B. Davis; George T. Flatman; Jerold W. Keith; Stanley R. Rapp; Theodore G. Storey

    1981-01-01

    FOCUS (Fire Operational Characteristics Using Simulation) is a computer simulation model for evaluating alternative fire management plans. This final report provides a broad overview of the FOCUS system, describes two major modules-fire suppression and cost, explains the role in the system of gaming large fires, and outlines the support programs and ways of...

  7. Measurement of Fire Radiative Energy from Space and Implications for Fire-Disaster Monitoring and Smoke Emissions Modeling

    NASA Technical Reports Server (NTRS)

    Ichoku, Charles

    2008-01-01

    Measurement of fire radiative energy (FRE) release rate or power (FRP) from satellite provides a vital mechanism for distinguishing different strengths of fires. Analysis of 1-km resolution fire data, acquired globally by the MODerate-resolution Imaging Spectro-radiometer (MODIS) sensor aboard the Terra and Aqua satellites from 2000 to 2006, showed instantaneous FRP values ranging between 0.02 MW and 1866 MW, to which simple thresholds can be applied to categorize fires by strength, in a similar fashion as the strengths of earthquakes and hurricanes. Analysis of regional mean FRP per unit area of land (FRP flux) shows that at peak fire season in certain regions, fires can be responsible for up to 0.2 W/m2 at peak time of day. When considered as the active fire contribution to the direct surface radiative forcing (RF) in the different fire regions, this order of magnitude of FRF fluxes is non negligible. It has been determined experimentally that the amount of FRE released by a fire over the course of its duration is directly proportional to the amount of biomass consumed by it. Furthermore, at the satellite observation scale, the rate of release of FRE (i.e. FRP) is proportional to the rate of biomass consumption, and that of emission of smoke particulates and eventually also other smoke constituents. Therefore, current research efforts are geared toward deriving simple parameterizations that will facilitate direct input of FRP measurements in models, not only to improve the accuracy of burned-biomass and smoke emissions estimations, but also to reduce the hitherto practiced heavy reliance on multiple indirect parameters with indeterminate uncertainties.

  8. Measurement of Fire Radiative Energy from Space and Implications for Fire-Disaster Monitoring and Smoke Emissions Modeling

    NASA Technical Reports Server (NTRS)

    Ichoku, Charles

    2008-01-01

    Measurement of fire radiative energy (FRE) release rate or power (FRP) from satellite provides a vital mechanism for distinguishing different strengths of fires. Analysis of 1-km resolution fire data, acquired globally by the MODerate-resolution Imaging Spectro-radiometer (MODIS) sensor aboard the Terra and Aqua satellites from 2000 to 2006, showed instantaneous FRP values ranging between 0.02 MW and 1866 MW, to which simple thresholds can be applied to categorize fires by strength, in a similar fashion as the strengths of earthquakes and hurricanes. Analysis of regional mean FRP per unit area of land (FRP flux) shows that at peak fire season in certain regions, fires can be responsible for up to 0.2 W/m2 at peak time of day. When considered as the active fire contribution to the direct surface radiative forcing (RF) in the different fire regions, this order of magnitude of FRF fluxes is non negligible. It has been determined experimentally that the amount of FRE released by a fire over the course of its duration is directly proportional to the amount of biomass consumed by it. Furthermore, at the satellite observation scale, the rate of release of FRE (i.e. FRP) is proportional to the rate of biomass consumption, and that of emission of smoke particulates and eventually also other smoke constituents. Therefore, current research efforts are geared toward deriving simple parameterizations that will facilitate direct input of FRP measurements in models, not only to improve the accuracy of burned-biomass and smoke emissions estimations, but also to reduce the hitherto practiced heavy reliance on multiple indirect parameters with indeterminate uncertainties.

  9. 75 FR 20516 - Special Conditions: Cirrus Design Corporation, Model SF50; Fire Extinguishing for Upper Aft...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-20

    ...; Fire Extinguishing for Upper Aft Fuselage Mounted Engine AGENCY: Federal Aviation Administration (FAA... protect such installed engines from fires, were not envisioned in the development of the part 23 normal... fire extinguishing system for the engine on the model SF50 is required. Regulations requiring...

  10. Spatially explicit modeling of mixed-severity fire regimes and landscape dynamics

    Treesearch

    Michael C. Wimberly; Rebecca S.H. Kennedy

    2008-01-01

    Simulation models of disturbance and succession are being increasingly applied to characterize landscape composition and dynamics under natural fire regimes, and to evaluate alternative management strategies for ecological restoration and fire hazard reduction. However, we have a limited understanding of how landscapes respond to changes in fire frequency, and about...

  11. A foundation for initial attack simulation: the Fried and Fried fire containment model

    Treesearch

    Jeremy S. Fried; Burton D. Fried

    2010-01-01

    The Fried and Fried containment algorithm, which models the effect of suppression efforts on fire growth, allows simulation of any mathematically representable fire shape, provides for "head" and "tail" attack tactics as well as parallel attack (building fireline parallel to but at some offset distance from the free-burning fire perimeter, alone and...

  12. Challenges of assessing fire and burn severity using field measures, remote sensing and modelling

    Treesearch

    Penelope Morgan; Robert E. Keane; Gregory K. Dillon; Theresa B. Jain; Andrew T. Hudak; Eva C. Karau; Pamela G. Sikkink; Zachery A. Holden; Eva K. Strand

    2014-01-01

    Comprehensive assessment of ecological change after fires have burned forests and rangelands is important if we are to understand, predict and measure fire effects. We highlight the challenges in effective assessment of fire and burn severity in the field and using both remote sensing and simulation models. We draw on diverse recent research for guidance on assessing...

  13. Assessing accuracy of point fire intervals across landscapes with simulation modelling

    Treesearch

    Russell A. Parsons; Emily K. Heyerdahl; Robert E. Keane; Brigitte Dorner; Joseph Fall

    2007-01-01

    We assessed accuracy in point fire intervals using a simulation model that sampled four spatially explicit simulated fire histories. These histories varied in fire frequency and size and were simulated on a flat landscape with two forest types (dry versus mesic). We used three sampling designs (random, systematic grids, and stratified). We assessed the sensitivity of...

  14. Modeling very large-fire occurrences over the continental United States from weather and climate forcing

    Treesearch

    R Barbero; J T Abatzoglou; E A Steel

    2014-01-01

    Very large-fires (VLFs) have widespread impacts on ecosystems, air quality, fire suppression resources, and in many regions account for a majority of total area burned. Empirical generalized linear models of the largest fires (>5000 ha) across the contiguous United States (US) were developed at ¡­60 km spatial and weekly temporal resolutions using solely atmospheric...

  15. Allocating resources to large wildland fires: a model with stochastic production rates

    Treesearch

    Romain Mees; David Strauss

    1992-01-01

    Wildland fires that grow out of the initial attack phase are responsible for most of the damage and burned area. We model the allocation of fire suppression resources (ground crews, engines, bulldozers, and airdrops) to these large fires. The fireline at a given future time is partitioned into homogeneous segments on the basis of fuel type, available resources, risk,...

  16. EcoSmart Fire as structure ignition model in wildland urban interface: predictions and validations

    Treesearch

    Mark A. Dietenberger; Charles R. Boardman

    2016-01-01

    EcoSmartFire is a Windows program that models heat damage and piloted ignition of structures from radiant exposure to discrete landscaped tree fires. It calculates the radiant heat transfer from cylindrical shaped fires to the walls and roof of the structure while accounting for radiation shadowing, attenuation, and ground reflections. Tests of litter burn, a 0.6 m...

  17. Firing patterns in a random network cellular automata model of the brain

    NASA Astrophysics Data System (ADS)

    Acedo, L.; Lamprianidou, E.; Moraño, J.-A.; Villanueva-Oller, J.; Villanueva, R.-J.

    2015-10-01

    One of the main challenges in the simulation of even reduced areas of the brain is the presence of a large number of neurons and a large number of connections among them. Even from a theoretical point of view, the behaviour of dynamical models of complex networks with high connectivity is unknown, precisely because the cost of computation is still unaffordable and it will likely be in the near future. In this paper we discuss the simulation of a cellular automata network model of the brain including up to one million sites with a maximum average of three hundred connections per neuron. This level of connectivity was achieved thanks to a distributed computing environment based on the BOINC (Berkeley Open Infrastructure for Network Computing) platform. Moreover, in this work we consider the interplay among excitatory neurons (which induce the excitation of their neighbours) and inhibitory neurons (which prevent resting neurons from firing and induce firing neurons to pass to the refractory state). Our objective is to classify the normal (noisy but asymptotically constant patterns) and the abnormal (high oscillations with spindle-like behaviour) patterns of activity in the model brain and their stability and parameter ranges in order to determine the role of excitatory and inhibitory compensatory effects in healthy and diseased individuals.

  18. Assessing the value of increased model resolution in forecasting fire danger

    Treesearch

    Jeanne Hoadley; Miriam Rorig; Ken Westrick; Larry Bradshaw; Sue Ferguson; Scott Goodrick; Paul Werth

    2003-01-01

    The fire season of 2000 was used as a case study to assess the value of increasing mesoscale model resolution for fire weather and fire danger forecasting. With a domain centered on Western Montana and Northern Idaho, MM5 simulations were run at 36, 12, and 4-km resolutions for a 30 day period at the height of the fire season. Verification analyses for meteorological...

  19. FNAS computational modeling

    NASA Technical Reports Server (NTRS)

    Franz, J. R.

    1993-01-01

    Numerical calculations of the electronic properties of liquid II-VI semiconductors, particularly CdTe and ZnTe were performed. The measured conductivity of these liquid alloys were modeled by assuming that the dominant temperature effect is the increase in the number of dangling bonds with increasing temperature. For low to moderate values of electron correlation, the calculated conductivity as a function of dangling bond concentration closely follows the measured conductivity as a function of temperature. Both the temperature dependence of the chemical potential and the thermal smearing in region of the Fermi surface have a large effect on calculated values of conductivity.

  20. Computer Security Models

    DTIC Science & Technology

    1984-09-01

    database data model. .- .- Brat it lea •.•<:’ - SUBJECTS: People, devices, processes, etc. i-’-" L" ". - OBJECTS: Data stored in the database and...uniquely identify data granules. It is not necessarily stored in the database with the data granule, but is either a tuple identifier (tid) in relational...the database management system. The user who first stores the data is allowed to retrieve or modify that data in case there are inputting errors. Add

  1. Classification Model for Forest Fire Hotspot Occurrences Prediction Using ANFIS Algorithm

    NASA Astrophysics Data System (ADS)

    Wijayanto, A. K.; Sani, O.; Kartika, N. D.; Herdiyeni, Y.

    2017-01-01

    This study proposed the application of data mining technique namely Adaptive Neuro-Fuzzy inference system (ANFIS) on forest fires hotspot data to develop classification models for hotspots occurrence in Central Kalimantan. Hotspot is a point that is indicated as the location of fires. In this study, hotspot distribution is categorized as true alarm and false alarm. ANFIS is a soft computing method in which a given inputoutput data set is expressed in a fuzzy inference system (FIS). The FIS implements a nonlinear mapping from its input space to the output space. The method of this study classified hotspots as target objects by correlating spatial attributes data using three folds in ANFIS algorithm to obtain the best model. The best result obtained from the 3rd fold provided low error for training (error = 0.0093676) and also low error testing result (error = 0.0093676). Attribute of distance to road is the most determining factor that influences the probability of true and false alarm where the level of human activities in this attribute is higher. This classification model can be used to develop early warning system of forest fire.

  2. Computational modeling of properties

    NASA Technical Reports Server (NTRS)

    Franz, Judy R.

    1994-01-01

    A simple model was developed to calculate the electronic transport parameters in disordered semiconductors in strong scattered regime. The calculation is based on a Green function solution to Kubo equation for the energy-dependent conductivity. This solution together with a rigorous calculation of the temperature-dependent chemical potential allows the determination of the dc conductivity and the thermopower. For wise-gap semiconductors with single defect bands, these transport properties are investigated as a function of defect concentration, defect energy, Fermi level, and temperature. Under certain conditions the calculated conductivity is quite similar to the measured conductivity in liquid II-VI semiconductors in that two distinct temperature regimes are found. Under different conditions the conductivity is found to decrease with temperature; this result agrees with measurements in amorphous Si. Finally the calculated thermopower can be positive or negative and may change sign with temperature or defect concentration.

  3. Component Breakout Computer Model

    DTIC Science & Technology

    1987-04-29

    Weapon Systems: A Policy Analysis." The Rand Graduate Institute. November 1983. Boger . D. "Statistical Models for Estimating Overhead Costs." M. S...SQUARE SCREEN PROGRAM BO DLS 70 LOCATE 3,5 100 PRINT " I I I I I I I I I I I I I I t I I I t I I i iiitiii I I I I i t I i 110 LOCATE 4,5 I 20...GOTO 4620 4610 REM ***********«««*«««**#«***********#******»,*###!^5|[^,„<c#,5|c„ dl -r C^M EED SUPPORT .c.50 REM A6(6)...N0 OF EMPLOYEES 4660 IF

  4. Thermal modeling of carbon-epoxy laminates in fire environments.

    SciTech Connect

    McGurn, Matthew T. , Buffalo, NY); DesJardin, Paul Edward , Buffalo, NY); Dodd, Amanda B.

    2010-10-01

    A thermal model is developed for the response of carbon-epoxy composite laminates in fire environments. The model is based on a porous media description that includes the effects of gas transport within the laminate along with swelling. Model comparisons are conducted against the data from Quintere et al. Simulations are conducted for both coupon level and intermediate scale one-sided heating tests. Comparisons of the heat release rate (HRR) as well as the final products (mass fractions, volume percentages, porosity, etc.) are conducted. Overall, the agreement between available the data and model is excellent considering the simplified approximations to account for flame heat flux. A sensitivity study using a newly developed swelling model shows the importance of accounting for laminate expansion for the prediction of burnout. Excellent agreement is observed between the model and data of the final product composition that includes porosity, mass fractions and volume expansion ratio.

  5. Modeling epoxy foams exposed to fire-like heat fluxes.

    SciTech Connect

    Hobbs, Michael L.

    2004-11-01

    A decomposition chemistry and heat transfer model to predict the response of removable epoxy foam (REF) exposed to fire-like heat fluxes is described. The epoxy foam was created using a perfluorohexane blowing agent with a surfactant. The model includes desorption of the blowing agent and surfactant, thermal degradation of the epoxy polymer, polymer fragment transport, and vapor-liquid equilibrium. An effective thermal conductivity model describes changes in thermal conductivity with reaction extent. Pressurization is modeled assuming: (1) no strain in the condensed-phase, (2) no resistance to gas-phase transport, (3) spatially uniform stress fields, and (4) no mass loss from the system due to venting. The model has been used to predict mass loss, pressure rise, and decomposition front locations for various small-scale and large-scale experiments performed by others. The framework of the model is suitable for polymeric foams with absorbed gases.

  6. Issues in Numerical Simulation of Fire Suppression

    SciTech Connect

    Tieszen, S.R.; Lopez, A.R.

    1999-04-12

    This paper outlines general physical and computational issues associated with performing numerical simulation of fire suppression. Fire suppression encompasses a broad range of chemistry and physics over a large range of time and length scales. The authors discuss the dominant physical/chemical processes important to fire suppression that must be captured by a fire suppression model to be of engineering usefulness. First-principles solutions are not possible due to computational limitations, even with the new generation of tera-flop computers. A basic strategy combining computational fluid dynamics (CFD) simulation techniques with sub-grid model approximations for processes that have length scales unresolvable by gridding is presented.

  7. Ch. 33 Modeling: Computational Thermodynamics

    SciTech Connect

    Besmann, Theodore M

    2012-01-01

    This chapter considers methods and techniques for computational modeling for nuclear materials with a focus on fuels. The basic concepts for chemical thermodynamics are described and various current models for complex crystalline and liquid phases are illustrated. Also included are descriptions of available databases for use in chemical thermodynamic studies and commercial codes for performing complex equilibrium calculations.

  8. Efficient Computational Model of Hysteresis

    NASA Technical Reports Server (NTRS)

    Shields, Joel

    2005-01-01

    A recently developed mathematical model of the output (displacement) versus the input (applied voltage) of a piezoelectric transducer accounts for hysteresis. For the sake of computational speed, the model is kept simple by neglecting the dynamic behavior of the transducer. Hence, the model applies to static and quasistatic displacements only. A piezoelectric transducer of the type to which the model applies is used as an actuator in a computer-based control system to effect fine position adjustments. Because the response time of the rest of such a system is usually much greater than that of a piezoelectric transducer, the model remains an acceptably close approximation for the purpose of control computations, even though the dynamics are neglected. The model (see Figure 1) represents an electrically parallel, mechanically series combination of backlash elements, each having a unique deadband width and output gain. The zeroth element in the parallel combination has zero deadband width and, hence, represents a linear component of the input/output relationship. The other elements, which have nonzero deadband widths, are used to model the nonlinear components of the hysteresis loop. The deadband widths and output gains of the elements are computed from experimental displacement-versus-voltage data. The hysteresis curve calculated by use of this model is piecewise linear beyond deadband limits.

  9. acme: The Amendable Coal-Fire Modeling Exercise. A C++ Class Library for the Numerical Simulation of Coal-Fires

    NASA Astrophysics Data System (ADS)

    Wuttke, Manfred W.

    2017-04-01

    At LIAG, we use numerical models to develop and enhance understanding of coupled transport processes and to predict the dynamics of the system under consideration. Topics include geothermal heat utilization, subrosion processes, and spontaneous underground coal fires. Although the details make it inconvenient if not impossible to apply a single code implementation to all systems, their investigations go along similar paths: They all depend on the solution of coupled transport equations. We thus saw a need for a modular code system with open access for the various communities to maximize the shared synergistic effects. To this purpose we develop the oops! ( open object-oriented parallel solutions) - toolkit, a C++ class library for the numerical solution of mathematical models of coupled thermal, hydraulic and chemical processes. This is used to develop problem-specific libraries like acme( amendable coal-fire modeling exercise), a class library for the numerical simulation of coal-fires and applications like kobra (Kohlebrand, german for coal-fire), a numerical simulation code for standard coal-fire models. Basic principle of the oops!-code system is the provision of data types for the description of space and time dependent data fields, description of terms of partial differential equations (pde), their discretisation and solving methods. Coupling of different processes, described by their particular pde is modeled by an automatic timescale-ordered operator-splitting technique. acme is a derived coal-fire specific application library, depending on oops!. If specific functionalities of general interest are implemented and have been tested they will be assimilated into the main oops!-library. Interfaces to external pre- and post-processing tools are easily implemented. Thus a construction kit which can be arbitrarily amended is formed. With the kobra-application constructed with acme we study the processes and propagation of shallow coal seam fires in particular in

  10. Prediction of forest fires occurrences with area-level Poisson mixed models.

    PubMed

    Boubeta, Miguel; Lombardía, María José; Marey-Pérez, Manuel Francisco; Morales, Domingo

    2015-05-01

    The number of fires in forest areas of Galicia (north-west of Spain) during the summer period is quite high. Local authorities are interested in analyzing the factors that explain this phenomenon. Poisson regression models are good tools for describing and predicting the number of fires per forest areas. This work employs area-level Poisson mixed models for treating real data about fires in forest areas. A parametric bootstrap method is applied for estimating the mean squared errors of fires predictors. The developed methodology and software are applied to a real data set of fires in forest areas of Galicia. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Fire in the Brazilian Amazon: A Spatially Explicit Model for Policy Impact Analysis

    NASA Technical Reports Server (NTRS)

    Arima, Eugenio Y.; Simmons, Cynthia S.; Walker, Robert T.; Cochrane, Mark A.

    2007-01-01

    This article implements a spatially explicit model to estimate the probability of forest and agricultural fires in the Brazilian Amazon. We innovate by using variables that reflect farmgate prices of beef and soy, and also provide a conceptual model of managed and unmanaged fires in order to simulate the impact of road paving, cattle exports, and conservation area designation on the occurrence of fire. Our analysis shows that fire is positively correlated with the price of beef and soy, and that the creation of new conservation units may offset the negative environmental impacts caused by the increasing number of fire events associated with early stages of frontier development.

  12. Fire in the Brazilian Amazon: A Spatially Explicit Model for Policy Impact Analysis

    NASA Technical Reports Server (NTRS)

    Arima, Eugenio Y.; Simmons, Cynthia S.; Walker, Robert T.; Cochrane, Mark A.

    2007-01-01

    This article implements a spatially explicit model to estimate the probability of forest and agricultural fires in the Brazilian Amazon. We innovate by using variables that reflect farmgate prices of beef and soy, and also provide a conceptual model of managed and unmanaged fires in order to simulate the impact of road paving, cattle exports, and conservation area designation on the occurrence of fire. Our analysis shows that fire is positively correlated with the price of beef and soy, and that the creation of new conservation units may offset the negative environmental impacts caused by the increasing number of fire events associated with early stages of frontier development.

  13. Turbulence radiation interaction modeling in hydrocarbon pool fire simulations

    SciTech Connect

    BURNS,SHAWN P.

    1999-12-01

    The importance of turbulent fluctuations in temperature and species concentration in thermal radiation transport modeling for combustion applications is well accepted by the radiation transport and combustion communities. A number of experimental and theoretical studies over the last twenty years have shown that fluctuations in the temperature and species concentrations may increase the effective emittance of a turbulent flame by as much as 50% to 300% over the value that would be expected from the mean temperatures and concentrations. With the possibility of such a large effect on the principal mode of heat transfer from a fire, it is extremely important for fire modeling efforts that turbulence radiation interaction be well characterized and possible modeling approaches understood. Toward this end, this report seeks to accomplish three goals. First, the principal turbulence radiation interaction closure terms are defined. Second, an order of magnitude analysis is performed to understand the relative importance of the various closure terms. Finally, the state of the art in turbulence radiation interaction closure modeling is reviewed. Hydrocarbon pool fire applications are of particular interest in this report and this is the perspective from which this review proceeds. Experimental and theoretical analysis suggests that, for this type of heavily sooting flame, the turbulent radiation interaction effect is dominated by the nonlinear dependence of the Planck function on the temperature. Additional effects due to the correlation between turbulent fluctuations in the absorptivity and temperature may be small relative to the Planck function effect for heavily sooting flames. This observation is drawn from a number of experimental and theoretical discussions. Nevertheless, additional analysis and data is needed to validate this observation for heavily sooting buoyancy dominated plumes.

  14. Analytical modeling of intumescent coating thermal protection system in a JP-5 fuel fire environment

    NASA Technical Reports Server (NTRS)

    Clark, K. J.; Shimizu, A. B.; Suchsland, K. E.; Moyer, C. B.

    1974-01-01

    The thermochemical response of Coating 313 when exposed to a fuel fire environment was studied to provide a tool for predicting the reaction time. The existing Aerotherm Charring Material Thermal Response and Ablation (CMA) computer program was modified to treat swelling materials. The modified code is now designated Aerotherm Transient Response of Intumescing Materials (TRIM) code. In addition, thermophysical property data for Coating 313 were analyzed and reduced for use in the TRIM code. An input data sensitivity study was performed, and performance tests of Coating 313/steel substrate models were carried out. The end product is a reliable computational model, the TRIM code, which was thoroughly validated for Coating 313. The tasks reported include: generation of input data, development of swell model and implementation in TRIM code, sensitivity study, acquisition of experimental data, comparisons of predictions with data, and predictions with intermediate insulation.

  15. A hidden Markov model approach to neuron firing patterns.

    PubMed Central

    Camproux, A C; Saunier, F; Chouvet, G; Thalabard, J C; Thomas, G

    1996-01-01

    Analysis and characterization of neuronal discharge patterns are of interest to neurophysiologists and neuropharmacologists. In this paper we present a hidden Markov model approach to modeling single neuron electrical activity. Basically the model assumes that each interspike interval corresponds to one of several possible states of the neuron. Fitting the model to experimental series of interspike intervals by maximum likelihood allows estimation of the number of possible underlying neuron states, the probability density functions of interspike intervals corresponding to each state, and the transition probabilities between states. We present an application to the analysis of recordings of a locus coeruleus neuron under three pharmacological conditions. The model distinguishes two states during halothane anesthesia and during recovery from halothane anesthesia, and four states after administration of clonidine. The transition probabilities yield additional insights into the mechanisms of neuron firing. Images FIGURE 3 PMID:8913581

  16. Computational Modeling of Multiphase Reactors.

    PubMed

    Joshi, J B; Nandakumar, K

    2015-01-01

    Multiphase reactors are very common in chemical industry, and numerous review articles exist that are focused on types of reactors, such as bubble columns, trickle beds, fluid catalytic beds, etc. Currently, there is a high degree of empiricism in the design process of such reactors owing to the complexity of coupled flow and reaction mechanisms. Hence, we focus on synthesizing recent advances in computational and experimental techniques that will enable future designs of such reactors in a more rational manner by exploring a large design space with high-fidelity models (computational fluid dynamics and computational chemistry models) that are validated with high-fidelity measurements (tomography and other detailed spatial measurements) to provide a high degree of rigor. Understanding the spatial distributions of dispersed phases and their interaction during scale up are key challenges that were traditionally addressed through pilot scale experiments, but now can be addressed through advanced modeling.

  17. A comparison of gray and non-gray modeling approaches to radiative transfer in pool fire simulations.

    PubMed

    Krishnamoorthy, Gautham

    2010-10-15

    Decoupled radiative heat transfer calculations of 30 cm-diameter toluene and heptane pool fires are performed employing the discrete ordinates method. The composition and temperature fields within the fires are created from detailed experimental measurements of soot volume fractions based on absorption and emission, temperature statistics and correlations found in the literature. The measured temperature variance data is utilized to compute the temperature self-correlation term for modeling turbulence-radiation interactions. In the toluene pool fire, the presence of cold soot near the fuel surface is found to suppress the average radiation feedback to the pool surface by 27%. The performances of four gray and three non-gray radiative property models for the gases are also compared. The average variations in radiative transfer predictions due to differences in the spectroscopic and experimental databases employed in the property model formulations are found to be between 10% and 20%. Clear differences between the gray and non-gray modeling strategies are seen when the mean beam length is computed based on traditionally employed geometric relations. Therefore, a correction to the mean beam length is proposed to improve the agreement between gray and non-gray modeling in simulations of open pool fires.

  18. Fire pollution for preindustrial, present day and future conditions in an interactive Earth System Model

    NASA Astrophysics Data System (ADS)

    Mezuman, Keren; Bauer, Susanne; Tsigaridis, Kostas

    2017-04-01

    A climate model with prognostic biomass burning allows us to study the drivers, feedbacks, and interactions of fire in time periods outside of the satellite era. As recent works have shown (e.g. Westerling et al., 2006; Veira et al., 2016) a region's fire activity is sensitive to changing temperatures and the arrival of spring, i.e. a changing climate. Other than regulating the atmospheric carbon monoxide budget, fires release to the atmosphere a suite of reactive gases and aerosol particles that affect air quality. We set out to study fire pollution of different regions in the world under different climate conditions by further developing the GISS fire model (Pechony and Shindell, 2009, 2010). We correlated the modeled flammability with MODIS fire counts, in a vegetation specific parameterization, which allowed us for the first time to interactively simulate climate and fire activity with GISS-ModelE2.1. Biomass burning occurrence was driven by environmental factors such as vapor pressure deficit and precipitation, as well as natural and anthropogenic ignition. With this new method we were able to attribute the source of the fire to either natural or anthropogenic origin. Present day results were evaluated against GFED4 data. Our results indicate that fire pollution is high in all time periods, but expected to play a bigger role in the future. We also show that humans play an important role in the spatial distribution of fire activity, and in curbing fire pollution.

  19. Interactive modelling of forest fires and their impacts on atmospheric composition

    NASA Astrophysics Data System (ADS)

    Mangeon, S.; Voulgarakis, A.; Folberth, G.

    2016-12-01

    Forest and wildland fires are a significant emission source of gases and aerosols to the atmosphere. In particular, biomass burning has been shown to be a significant driver of interannual variability and short-term climate forcings. Fires emit a wide variety of compounds to the atmosphere, from greenhouse gases to aerosols. Conversely, weather and climate also drive fire occurrence, creating potential feedbacks between climate, atmospheric composition, and fire. Here, we will present INFERNO (INteractive Fires and Emissions algoRithm for Natural envirOnments, described in Mangeon et al., 2016), a reduced complexity approach to global fire modelling coupled to interactive atmospheric composition in the UK Met Office's Unified Model. We will first show the coupled model's performance in capturing burnt area and fire emissions. We will then demonstrate how fires impact atmospheric composition in the global model for present-day scenarios: with our interactive scheme but also with reference datasets of global fire emissions, as well as in simulations assuming no fire emissions. In particular, we will investigate the role of fires on the mean present-day state, the seasonal cycle, and the interannual variability of important atmospheric constituents (e.g., CO and aerosols).

  20. The Cerro Grande Fire - From Wildlife Modeling Through the Fire Aftermath

    SciTech Connect

    Rudell, T. M.; Gille, R. W.

    2001-01-01

    The Cerro Grande Fire developed from a prescribed burn by the National Park Service at Bandelier National Monument near Los Alamos, New Mexico. When the burn went out of control and became a wildfire, it attracted worldwide attention because it threatened the birthplace of the atomic bomb, Los Alamos National Laboratory (LANL). Was LANL prepared for a fire? What lessons have been learned?

  1. The Cerro Grande Fire - From Wildfire Modeling Through the Fire Aftermath

    SciTech Connect

    Rudell, T. M.; Gille, R. W.

    2001-01-01

    The Cerro Grande Fire developed from a prescribed burn by the National Park Service at Bandelier National Monument near Los Alamos, New Mexico. When the burn went out of control and became a wildfire, it attracted worldwide attention because it threatened the birthplace of the atomic bomb, Los Alamos National Laboratory (LANL). Was LANL prepared for a fire? What lessons have been learned?

  2. Modelling the impacts of reoccurring fires in tropical savannahs using Biome-BGC.

    NASA Astrophysics Data System (ADS)

    Fletcher, Charlotte; Petritsch, Richard; Pietsch, Stephan

    2010-05-01

    Fires are a dominant feature of tropical savannahs and have occurred throughout history by natural as well as human-induced means. These fires have a profound influence on the landscape in terms of flux dynamics and vegetative species composition. This study attempts to understand the impacts of fire regimes on flux dynamics and vegetation composition in savannahs using the Biome-BGC model. The Batéké Plateau, Gabon - an area of savannah grasslands in the Congo basin, serves as a case-study. To achieve model validation for savannahs, data sets from stands with differing levels of past burning are used. It is hypothesised that the field measurements from those stands with lower-levels of past burning will correlate with the Biome-BGC model output, meaning that the model is validated for the savannah excluding fire regimes. However, in reality, fire is frequent in the savannah. Data on past fire events are available from the Moderate Resolution Imaging Spectroradiometer (MODIS) to provide the fire regimes of the model. As the field data-driven measurements of the burnt stands are influenced by fire in the savannah, this will therefore result in a Biome-BGC model validated for the impacts of fire on savannah ecology. The validated model can then be used to predict the savannah's flux dynamics under the fire scenarios expected with climate and/or human impact change.

  3. Verification of the naval oceanic vertical aerosol model during FIRE

    NASA Technical Reports Server (NTRS)

    Davidson, K. L.; Deleeuw, G.; Gathman, S. G.; Jensen, D. R.

    1990-01-01

    The value of Naval Oceanic Vertical Aerosol Model (NOVAM) is illustrated for estimating the non-uniform and non-logarithmic extinction profiles, based on a severe test involving conditions close to and beyond the limits of applicability of NOVAM. A more comprehensive evaluation of NOVAM from the FIRE data is presented, which includes a clear-air case. For further evaluation more data are required on the vertical structure of the extinction in the marine atmospheric boundary layer (MABL), preferably for different meteorological conditions and in different geographic areas (e.g., ASTEX).

  4. Rapid response tools and datasets for post-fire hydrological modeling applied to the High Park Fire

    NASA Astrophysics Data System (ADS)

    Dobre, M.; Miller, M. E.; MacDonald, L. H.; Elliot, W. J.; Billmire, M.; Kampf, S. K.; Robichaud, P. R.; Schmeer, S.; Serocki, E.

    2016-12-01

    Post-fire flooding and erosion can pose a serious threat to life, property and natural resources. Time is critical in post-fire remediation as plans and treatments must be developed and deployed before the first major storms to be effective. We have developed an interactive database for the continental United States to facilitate rapid assessment of runoff and erosion risks from burned watersheds. This interactive database allows modelers to upload earth observations of soil burn severity and quickly download spatially-explicit model inputs at either 10- or 30-m resolution for process-based models, particularly WEPP based models (http://geodjango.mtri.org/geowepp/). Other modeling applications include agriculture, construction, or mining. The online database has allowed post-fire remediation teams in the western U.S. to rapidly predict post-fire erosion and effects of mulching treatments for over a dozen fires ranging in size from 4-540 km2. There is an urgent need for field data to validate these modeling efforts. One of the first fires to utilize this database was the High Park Fire, which burned approximately 330 km2 in northcentral Colorado in June 2012. Beginning in late summer of 2012 rainfall, site characteristics, and sediment production were measured for 21 unmulched and 8 mulched hillslopes. In 2013 sediment yields from unmulched and mulched hillslopes averaged 7.9 and 3.0 Mg ha-1, respectively, and these values dropped by more than an order of magnitude in 2014. Initial comparisons of measured and predicted hillslope sediment yields were poorly correlated, although they are of a similar order of magnitude. The causes of the poor correlation are being evaluated, and include a discrepancy between the small scale of the measured hillslopes and the much larger scale of the modeled hillslopes, problems with some sediment fences overtopping, an exceptionally large and long duration storm in September 2013, and the lack of suspended sediment data. Additional

  5. Computational models of adult neurogenesis

    NASA Astrophysics Data System (ADS)

    Cecchi, Guillermo A.; Magnasco, Marcelo O.

    2005-10-01

    Experimental results in recent years have shown that adult neurogenesis is a significant phenomenon in the mammalian brain. Little is known, however, about the functional role played by the generation and destruction of neurons in the context of an adult brain. Here, we propose two models where new projection neurons are incorporated. We show that in both models, using incorporation and removal of neurons as a computational tool, it is possible to achieve a higher computational efficiency that in purely static, synapse-learning-driven networks. We also discuss the implication for understanding the role of adult neurogenesis in specific brain areas like the olfactory bulb and the dentate gyrus.

  6. Rapid response tools and datasets for post-fire modeling: Linking Earth Observations and process-based hydrological models to support post-fire remediation

    Treesearch

    M. E. Miller; M. Billmire; W. J. Elliot; K. A. Endsley; P. R. Robichaud

    2015-01-01

    Preparation is key to utilizing Earth Observations and process-based models to support post-wildfire mitigation. Post-fire flooding and erosion can pose a serious threat to life, property and municipal water supplies. Increased runoff and sediment delivery due to the loss of surface cover and fire-induced changes in soil properties are of great concern. Remediation...

  7. Nano-filled epoxy: Mechanical and fire behavior and modeling of nanocomposite columns under fire

    NASA Astrophysics Data System (ADS)

    Bietto, Stefano

    2007-12-01

    In this work, fracture, mechanical, and flammability tests, along with a modeling of the stability of nanocomposite columns under fire are presented for nano-filled Diglycidyl Ether of Bisphenol A epoxy. The nanofillers used are montmorillonite nanoclays and carbon nanofibers. Three types of nanocomposites are manufactured: epoxy-clay, epoxy-carbon nanofiber, and epoxy-clay-carbon nanofiber nanocomposites. Fracture tests performed include Izod impact and fracture toughness, for the determination of the net Izod impact strength, the stress intensity factor, and the critical energy release rate. With static mechanical tests the tensile and flexural properties of the nanocomposites are measured. Flammability tests made by cone calorimetry are used to determine the Heat Release Rate, Mass Loss Rate, time to ignition, to Peak of heat Release rate and to flameout, and total smoke and heat released. A mathematical modeling of the stability of columns, made of the same nanocomposites tested, burning continuously in one side is performed. Three configurations are considered: uniform burning along the span, and burning spot at the center and at the corner of the column. The testing and the mathematical modeling reveal the higher mechanical strength and superior flammability properties produced by addition of nanofillers.

  8. Enhanced absorption cycle computer model

    NASA Astrophysics Data System (ADS)

    Grossman, G.; Wilk, M.

    1993-09-01

    Absorption heat pumps have received renewed and increasing attention in the past two decades. The rising cost of electricity has made the particular features of this heat-powered cycle attractive for both residential and industrial applications. Solar-powered absorption chillers, gas-fired domestic heat pumps, and waste-heat-powered industrial temperature boosters are a few of the applications recently subjected to intensive research and development. The absorption heat pump research community has begun to search for both advanced cycles in various multistage configurations and new working fluid combinations with potential for enhanced performance and reliability. The development of working absorption systems has created a need for reliable and effective system simulations. A computer code has been developed for simulation of absorption systems at steady state in a flexible and modular form, making it possible to investigate various cycle configurations with different working fluids. The code is based on unit subroutines containing the governing equations for the system's components and property subroutines containing thermodynamic properties of the working fluids. The user conveys to the computer an image of his cycle by specifying the different subunits and their interconnections. Based on this information, the program calculates the temperature, flow rate, concentration, pressure, and vapor fraction at each state point in the system, and the heat duty at each unit, from which the coefficient of performance (COP) may be determined. This report describes the code and its operation, including improvements introduced into the present version. Simulation results are described for LiBr-H2O triple-effect cycles, LiCl-H2O solar-powered open absorption cycles, and NH3-H2O single-effect and generator-absorber heat exchange cycles. An appendix contains the user's manual.

  9. Error associated with model predictions of wildland fire rate of spread

    Treesearch

    Miguel G. Cruz; Martin E. Alexander

    2015-01-01

    How well can we expect to predict the spread rate of wildfires and prescribed fires? The degree of accuracy in model predictions of wildland fire behaviour characteristics are dependent on the model's applicability to a given situation, the validity of the model's relationships, and the reliability of the model input data (Alexander and Cruz 2013b#. We...

  10. Computational Modeling Method for Superalloys

    NASA Technical Reports Server (NTRS)

    Bozzolo, Guillermo; Noebe, Ronald D.; Gayda, John

    1997-01-01

    Computer modeling based on theoretical quantum techniques has been largely inefficient due to limitations on the methods or the computer needs associated with such calculations, thus perpetuating the notion that little help can be expected from computer simulations for the atomistic design of new materials. In a major effort to overcome these limitations and to provide a tool for efficiently assisting in the development of new alloys, we developed the BFS method for alloys, which together with the experimental results from previous and current research that validate its use for large-scale simulations, provide the ideal grounds for developing a computationally economical and physically sound procedure for supplementing the experimental work at great cost and time savings.

  11. Random Sampling with Interspike-Intervals of the Exponential Integrate and Fire Neuron: A Computational Interpretation of UP-States

    PubMed Central

    Steimer, Andreas; Schindler, Kaspar

    2015-01-01

    Oscillations between high and low values of the membrane potential (UP and DOWN states respectively) are an ubiquitous feature of cortical neurons during slow wave sleep and anesthesia. Nevertheless, a surprisingly small number of quantitative studies have been conducted only that deal with this phenomenon’s implications for computation. Here we present a novel theory that explains on a detailed mathematical level the computational benefits of UP states. The theory is based on random sampling by means of interspike intervals (ISIs) of the exponential integrate and fire (EIF) model neuron, such that each spike is considered a sample, whose analog value corresponds to the spike’s preceding ISI. As we show, the EIF’s exponential sodium current, that kicks in when balancing a noisy membrane potential around values close to the firing threshold, leads to a particularly simple, approximative relationship between the neuron’s ISI distribution and input current. Approximation quality depends on the frequency spectrum of the current and is improved upon increasing the voltage baseline towards threshold. Thus, the conceptually simpler leaky integrate and fire neuron that is missing such an additional current boost performs consistently worse than the EIF and does not improve when voltage baseline is increased. For the EIF in contrast, the presented mechanism is particularly effective in the high-conductance regime, which is a hallmark feature of UP-states. Our theoretical results are confirmed by accompanying simulations, which were conducted for input currents of varying spectral composition. Moreover, we provide analytical estimations of the range of ISI distributions the EIF neuron can sample from at a given approximation level. Such samples may be considered by any algorithmic procedure that is based on random sampling, such as Markov Chain Monte Carlo or message-passing methods. Finally, we explain how spike-based random sampling relates to existing

  12. Real Time Fire Reconnaissance Satellite Monitoring System Failure Model

    NASA Astrophysics Data System (ADS)

    Nino Prieto, Omar Ariosto; Colmenares Guillen, Luis Enrique

    2013-09-01

    In this paper the Real Time Fire Reconnaissance Satellite Monitoring System is presented. This architecture is a legacy of the Detection System for Real-Time Physical Variables which is undergoing a patent process in Mexico. The methodologies for this design are the Structured Analysis for Real Time (SA- RT) [8], and the software is carried out by LACATRE (Langage d'aide à la Conception d'Application multitâche Temps Réel) [9,10] Real Time formal language. The system failures model is analyzed and the proposal is based on the formal language for the design of critical systems and Risk Assessment; AltaRica. This formal architecture uses satellites as input sensors and it was adapted from the original model which is a design pattern for physical variation detection in Real Time. The original design, whose task is to monitor events such as natural disasters and health related applications, or actual sickness monitoring and prevention, as the Real Time Diabetes Monitoring System, among others. Some related work has been presented on the Mexican Space Agency (AEM) Creation and Consultation Forums (2010-2011), and throughout the International Mexican Aerospace Science and Technology Society (SOMECYTA) international congress held in San Luis Potosí, México (2012). This Architecture will allow a Real Time Fire Satellite Monitoring, which will reduce the damage and danger caused by fires which consumes the forests and tropical forests of Mexico. This new proposal, permits having a new system that impacts on disaster prevention, by combining national and international technologies and cooperation for the benefit of humankind.

  13. Climate Modeling Computing Needs Assessment

    NASA Astrophysics Data System (ADS)

    Petraska, K. E.; McCabe, J. D.

    2011-12-01

    This paper discusses early findings of an assessment of computing needs for NASA science, engineering and flight communities. The purpose of this assessment is to document a comprehensive set of computing needs that will allow us to better evaluate whether our computing assets are adequately structured to meet evolving demand. The early results are interesting, already pointing out improvements we can make today to get more out of the computing capacity we have, as well as potential game changing innovations for the future in how we apply information technology to science computing. Our objective is to learn how to leverage our resources in the best way possible to do more science for less money. Our approach in this assessment is threefold: Development of use case studies for science workflows; Creating a taxonomy and structure for describing science computing requirements; and characterizing agency computing, analysis, and visualization resources. As projects evolve, science data sets increase in a number of ways: in size, scope, timelines, complexity, and fidelity. Generating, processing, moving, and analyzing these data sets places distinct and discernable requirements on underlying computing, analysis, storage, and visualization systems. The initial focus group for this assessment is the Earth Science modeling community within NASA's Science Mission Directorate (SMD). As the assessment evolves, this focus will expand to other science communities across the agency. We will discuss our use cases, our framework for requirements and our characterizations, as well as our interview process, what we learned and how we plan to improve our materials after using them in the first round of interviews in the Earth Science Modeling community. We will describe our plans for how to expand this assessment, first into the Earth Science data analysis and remote sensing communities, and then throughout the full community of science, engineering and flight at NASA.

  14. Computer program for calculating and plotting fire direction and rate of spread.

    Treesearch

    James E. Eenigenburg

    1987-01-01

    Presents an analytical procedure that uses a FORTRAN 77 program to estimate fire direction and rate of spread. The program also calculates the variability of these parameters, both for subsections of the fire and for the fires as a whole. An option in the program allows users with a CALCOMP plotter to obtain a map of the fire with spread vectors.

  15. The Effect of Computer-Based Simulation Training on Fire Ground Incident Commander Decision Making

    ERIC Educational Resources Information Center

    Hall, Kurt A.

    2010-01-01

    Since the establishment of the first volunteer fire brigades in the United States, firefighters have lost their lives in fire fighting operations at emergency incidents and live-fire training activities. While there are various reasons for these firefighter deaths and injuries, the United States Fire Administration (2002) reported that many of…

  16. The Effect of Computer-Based Simulation Training on Fire Ground Incident Commander Decision Making

    ERIC Educational Resources Information Center

    Hall, Kurt A.

    2010-01-01

    Since the establishment of the first volunteer fire brigades in the United States, firefighters have lost their lives in fire fighting operations at emergency incidents and live-fire training activities. While there are various reasons for these firefighter deaths and injuries, the United States Fire Administration (2002) reported that many of…

  17. An intermediate process-based fire parameterization in Dynamic Global Vegetation Model

    NASA Astrophysics Data System (ADS)

    Li, F.; Zeng, X.

    2011-12-01

    An intermediate process-based fire parameterization has been developed for global fire simulation. It fits the framework of Dynamic Global Vegetation Model (DGVM) which has been a pivot component in Earth System Model (ESM). The fire parameterization comprises three parts: fire occurrence, fire spread, and fire impact. In the first part, the number of fires is determined by ignition counts due to anthropogenic and natural causes and three constraints: fuel load, fuel moisture, and human suppression. Human caused ignition and suppression is explicitly considered as a nonlinear function of population density. The fire counts rather than fire occurrence probability is estimated to avoid underestimating the observed high burned area fraction in tropical savannas where fire occurs frequently. In the second part, post-fire region is assumed to be elliptical in shape with the wind direction along the major axis and the point of ignition at one of the foci. Burned area is determined by fire spread rate,fire duration, and fire counts. Mathematical characteristics of ellipse and some mathematical derivations are used to avoid redundant and unreasonable equations and assumptions in the CTEM-FIRE and make the parameterization equations self-consistently. In the third part, the impact of fire on vegetation component and structure, carbon cycle, trace gases and aerosol emissions are taken into account. The new estimates of trace gas and aerosol emissions due to biomass burning offers an interface with aerosol and atmospheric chemistry model in ESMs. Furthermore, in the new fire parameterization, fire occurrence part and fire spread part can be updated hourly or daily, and fire impact part can be updated daily, monthly, or annually. Its flexibility in selection of time-step length makes it easily applied to various DGVMs. The improved Community Land Model 3.0's Dynamic Global Vegetation Model (CLM-DGVM) is used as the model platform to assess the global performance of the new

  18. What determines area burned in large landscapes? Insights from a decade of comparative landscape-fire modelling

    Treesearch

    Geoffrey J. Cary; Robert E. Keane; Mike D. Flannigan; Ian D. Davies; Russ A. Parsons

    2015-01-01

    Understanding what determines area burned in large landscapes is critical for informing wildland fire management in fire-prone environments and for representing fire activity in Dynamic Global Vegetation Models. For the past ten years, a group of landscape-fire modellers have been exploring the relative influence of key determinants of area burned in temperate and...

  19. Developing custom fire behavior fuel models from ecologically complex fuel structures for upper Atlantic Coastal Plain forests

    Treesearch

    Bernard R. Parresol; Joe H. Scott; Anne Andreu; Susan Prichard; Laurie Kurth

    2012-01-01

    Currently geospatial fire behavior analyses are performed with an array of fire behavior modeling systems such as FARSITE, FlamMap, and the Large Fire Simulation System. These systems currently require standard or customized surface fire behavior fuel models as inputs that are often assigned through remote sensing information. The ability to handle hundreds or...

  20. The Egg Series: Using Simple Computer Models

    ERIC Educational Resources Information Center

    Statz, Joyce; Miller, Leland

    1978-01-01

    A model computer which uses a common egg carton to represent computer memory is suggested for giving students a basic understanding of a computer's organization. Several programs using the model are included. (MN)

  1. Research and management issues in large-scale fire modeling

    Treesearch

    David L. Peterson; Daniel L. Schmoldt

    2000-01-01

    In 1996, a team of North American fire scientists and resource managers convened to assess the effects of fire disturbance on ecosystems and to develop scientific recommendations for future fire research and management activities. These recommendations - elicited with the Analytic Hierarchy Process - include numerically ranked scientific and managerial questions and...

  2. Computational Modeling of Mitochondrial Function

    PubMed Central

    Cortassa, Sonia; Aon, Miguel A.

    2012-01-01

    The advent of techniques with the ability to scan massive changes in cellular makeup (genomics, proteomics, etc.) has revealed the compelling need for analytical methods to interpret and make sense of those changes. Computational models built on sound physico-chemical mechanistic basis are unavoidable at the time of integrating, interpreting, and simulating high-throughput experimental data. Another powerful role of computational models is predicting new behavior provided they are adequately validated. Mitochondrial energy transduction has been traditionally studied with thermodynamic models. More recently, kinetic or thermo-kinetic models have been proposed, leading the path toward an understanding of the control and regulation of mitochondrial energy metabolism and its interaction with cytoplasmic and other compartments. In this work, we outline the methods, step-by-step, that should be followed to build a computational model of mitochondrial energetics in isolation or integrated to a network of cellular processes. Depending on the question addressed by the modeler, the methodology explained herein can be applied with different levels of detail, from the mitochondrial energy producing machinery in a network of cellular processes to the dynamics of a single enzyme during its catalytic cycle. PMID:22057575

  3. Kilohertz Frequency Deep Brain Stimulation Is Ineffective at Regularizing the Firing of Model Thalamic Neurons.

    PubMed

    Couto, João; Grill, Warren M

    2016-01-01

    Deep brain stimulation (DBS) is an established therapy for movement disorders, including tremor, dystonia, and Parkinson's disease, but the mechanisms of action are not well understood. Symptom suppression by DBS typically requires stimulation frequencies ≥100 Hz, but when the frequency is increased above ~2 kHz, the effectiveness in tremor suppression declines (Benabid et al., 1991). We sought to test the hypothesis that the decline in efficacy at high frequencies is associated with desynchronization of the activity generated within a population of stimulated neurons. Regularization of neuronal firing is strongly correlated with tremor suppression by DBS, and desynchronization would disrupt the regularization of neuronal activity. We implemented computational models of CNS axons with either deterministic or stochastic membrane dynamics, and quantified the response of populations of model nerve fibers to extracellular stimulation at different frequencies and amplitudes. As stimulation frequency was increased from 2 to 80 Hz the regularity of neuronal firing increased (as assessed with direct estimates of entropy), in accord with the clinical effects on tremor of increasing stimulation frequency (Kuncel et al., 2006). Further, at frequencies between 80 and 500 Hz, increasing the stimulation amplitude (i.e., the proportion of neurons activated by the stimulus) increased the regularity of neuronal activity across the population, in accord with the clinical effects on tremor of stimulation amplitude (Kuncel et al., 2007). However, at stimulation frequencies above 1 kHz the regularity of neuronal firing declined due to irregular patterns of action potential generation and conduction block. The reductions in neuronal regularity that occurred at high frequencies paralleled the previously reported decline in tremor reduction and may be responsible for the loss of efficacy of DBS at very high frequencies. This analysis provides further support for the hypothesis that

  4. Kilohertz Frequency Deep Brain Stimulation Is Ineffective at Regularizing the Firing of Model Thalamic Neurons

    PubMed Central

    Couto, João; Grill, Warren M.

    2016-01-01

    Deep brain stimulation (DBS) is an established therapy for movement disorders, including tremor, dystonia, and Parkinson's disease, but the mechanisms of action are not well understood. Symptom suppression by DBS typically requires stimulation frequencies ≥100 Hz, but when the frequency is increased above ~2 kHz, the effectiveness in tremor suppression declines (Benabid et al., 1991). We sought to test the hypothesis that the decline in efficacy at high frequencies is associated with desynchronization of the activity generated within a population of stimulated neurons. Regularization of neuronal firing is strongly correlated with tremor suppression by DBS, and desynchronization would disrupt the regularization of neuronal activity. We implemented computational models of CNS axons with either deterministic or stochastic membrane dynamics, and quantified the response of populations of model nerve fibers to extracellular stimulation at different frequencies and amplitudes. As stimulation frequency was increased from 2 to 80 Hz the regularity of neuronal firing increased (as assessed with direct estimates of entropy), in accord with the clinical effects on tremor of increasing stimulation frequency (Kuncel et al., 2006). Further, at frequencies between 80 and 500 Hz, increasing the stimulation amplitude (i.e., the proportion of neurons activated by the stimulus) increased the regularity of neuronal activity across the population, in accord with the clinical effects on tremor of stimulation amplitude (Kuncel et al., 2007). However, at stimulation frequencies above 1 kHz the regularity of neuronal firing declined due to irregular patterns of action potential generation and conduction block. The reductions in neuronal regularity that occurred at high frequencies paralleled the previously reported decline in tremor reduction and may be responsible for the loss of efficacy of DBS at very high frequencies. This analysis provides further support for the hypothesis that

  5. Modeling Forest Fire Occurrences Using Count-Data Mixed Models in Qiannan Autonomous Prefecture of Guizhou Province in China

    PubMed Central

    Ji, Ping

    2015-01-01

    Forest fires can cause catastrophic damage on natural resources. In the meantime, it can also bring serious economic and social impacts. Meteorological factors play a critical role in establishing conditions favorable for a forest fire. Effective prediction of forest fire occurrences could prevent or minimize losses. This paper uses count data models to analyze fire occurrence data which is likely to be dispersed and frequently contain an excess of zero counts (no fire occurrence). Such data have commonly been analyzed using count data models such as a Poisson model, negative binomial model (NB), zero-inflated models, and hurdle models. Data we used in this paper is collected from Qiannan autonomous prefecture of Guizhou province in China. Using the fire occurrence data from January to April (spring fire season) for the years 1996 through 2007, we introduced random effects to the count data models. In this study, the results indicated that the prediction achieved through NB model provided a more compelling and credible inferential basis for fitting actual forest fire occurrence, and mixed-effects model performed better than corresponding fixed-effects model in forest fire forecasting. Besides, among all meteorological factors, we found that relative humidity and wind speed is highly correlated with fire occurrence. PMID:25790309

  6. Modeling forest fire occurrences using count-data mixed models in Qiannan autonomous prefecture of Guizhou province in China.

    PubMed

    Xiao, Yundan; Zhang, Xiongqing; Ji, Ping

    2015-01-01

    Forest fires can cause catastrophic damage on natural resources. In the meantime, it can also bring serious economic and social impacts. Meteorological factors play a critical role in establishing conditions favorable for a forest fire. Effective prediction of forest fire occurrences could prevent or minimize losses. This paper uses count data models to analyze fire occurrence data which is likely to be dispersed and frequently contain an excess of zero counts (no fire occurrence). Such data have commonly been analyzed using count data models such as a Poisson model, negative binomial model (NB), zero-inflated models, and hurdle models. Data we used in this paper is collected from Qiannan autonomous prefecture of Guizhou province in China. Using the fire occurrence data from January to April (spring fire season) for the years 1996 through 2007, we introduced random effects to the count data models. In this study, the results indicated that the prediction achieved through NB model provided a more compelling and credible inferential basis for fitting actual forest fire occurrence, and mixed-effects model performed better than corresponding fixed-effects model in forest fire forecasting. Besides, among all meteorological factors, we found that relative humidity and wind speed is highly correlated with fire occurrence.

  7. [Prediction model of human-caused fire occurrence in the boreal forest of northern China].

    PubMed

    Guo, Fu-tao; Su, Zhang-wen; Wang, Guang-yu; Wang, Qiang; Sun, Long; Yang, Ting-ting

    2015-07-01

    The Chinese boreal forest is an important forest resource in China. However, it has been suffering serious disturbances of forest fires, which were caused equally by natural disasters (e.g., lightning) and human activities. The literature on human-caused fires indicates that climate, topography, vegetation, and human infrastructure are significant factors that impact the occurrence and spread of human-caused fires. But the studies on human-caused fires in the boreal forest of northern China are limited and less comprehensive. This paper applied the spatial analysis tools in ArcGIS 10.0 and Logistic regression model to investigate the driving factors of human-caused fires. Our data included the geographic coordinates of human-caused fires, climate factors during year 1974-2009, topographic information, and forest map. The results indicated that distance to railway (x1) and average relative humidity (x2) significantly impacted the occurrence of human-caused fire in the study area. The logistic model for predicting the fire occurrence probability was formulated as P= 1/[11+e-(3.026-0.00011x1-0.047x2)] with an accuracy rate of 80%. The above model was used to predict the monthly fire occurrence during the fire season of 2015 based on the HADCM2 future weather data. The prediction results showed that the high risk of human-caused fire occurrence concentrated in the months of April, May, June and August, while April and May had higher risk of fire occurrence than other months. According to the spatial distribution of possibility of fire occurrence, the high fire risk zones were mainly in the west and southwest of Tahe, where the major railways were located.

  8. Measuring behaviours for escaping from house fires: use of latent variable models to summarise multiple behaviours.

    PubMed

    Ploubidis, G B; Edwards, P; Kendrick, D

    2015-12-15

    This paper reports the development and testing of a construct measuring parental fire safety behaviours for planning escape from a house fire. Latent variable modelling of data on parental-reported fire safety behaviours and plans for escaping from a house fire and multivariable logistic regression to quantify the association between groups defined by the latent variable modelling and parental-report of having a plan for escaping from a house fire. Data comes from 1112 participants in a cluster randomised controlled trial set in children's centres in 4 study centres in the UK. A two class model provided the best fit to the data, combining responses to five fire safety planning behaviours. The first group ('more behaviours for escaping from a house fire') comprised 86% of participants who were most likely to have a torch, be aware of how their smoke alarm sounds, to have external door and window keys accessible, and exits clear. The second group ('fewer behaviours for escaping from a house fire') comprised 14% of participants who were less likely to report these five behaviours. After adjusting for potential confounders, participants allocated to the 'more behaviours for escaping from a house fire group were 2.5 times more likely to report having an escape plan (OR 2.48; 95% CI 1.59-3.86) than those in the "fewer behaviours for escaping from a house fire" group. Multiple fire safety behaviour questions can be combined into a single binary summary measure of fire safety behaviours for escaping from a house fire. Our findings will be useful to future studies wishing to use a single measure of fire safety planning behaviour as measures of outcome or exposure. NCT 01452191. Date of registration 13/10/2011.

  9. Computational modelling approaches to vaccinology.

    PubMed

    Pappalardo, Francesco; Flower, Darren; Russo, Giulia; Pennisi, Marzio; Motta, Santo

    2015-02-01

    Excepting the Peripheral and Central Nervous Systems, the Immune System is the most complex of somatic systems in higher animals. This complexity manifests itself at many levels from the molecular to that of the whole organism. Much insight into this confounding complexity can be gained through computational simulation. Such simulations range in application from epitope prediction through to the modelling of vaccination strategies. In this review, we evaluate selectively various key applications relevant to computational vaccinology: these include technique that operates at different scale that is, from molecular to organisms and even to population level.

  10. Neurometric Modeling: Computational Modeling of Individual Brains

    DTIC Science & Technology

    2011-05-16

    Army Research Office P.O. Box 12211 Research Triangle Park, NC 27709-2211 15. SUBJECT TERMS Neural networks, computational neuroscience, fMRI ...obtained using functional MRI. Algorithmic processing of these measurements can exploit a variety of statistical machine learning methods to... statistical machine learning methods to synthesize a new kind of neuro-cognitive model, which we call neurometric models. These executable models could be

  11. Computational Modeling for Bedside Application

    PubMed Central

    Kerckhoffs, Roy C.P.; Narayan, Sanjiv M.; Omens, Jeffrey H.; Mulligan, Lawrence J.; McCulloch, Andrew D.

    2008-01-01

    With growing computer power, novel diagnostic and therapeutic medical technologies, coupled with an increasing knowledge of pathophysiology from gene to organ systems, it is increasingly feasible to apply multi-scale patient-specific modeling based on proven disease mechanisms to guide and predict the response to therapy in many aspects of medicine. This is an exciting and relatively new approach, for which efficient methods and computational tools are of the utmost importance. Already, investigators have designed patient-specific models in almost all areas of human physiology. Not only will these models be useful on a large scale in the clinic to predict and optimize the outcome from surgery and non-interventional therapy, but they will also provide pathophysiologic insights from cell to tissue to organ system, and therefore help to understand why specific interventions succeed or fail. PMID:18598988

  12. Obtaining a Pragmatic Representation of Fire Disturbance in Dynamic Vegetation Models by Assimilating Earth Observation Data

    NASA Astrophysics Data System (ADS)

    Kantzas, Euripides; Quegan, Shaun

    2015-04-01

    Fire constitutes a violent and unpredictable pathway of carbon from the terrestrial biosphere into the atmosphere. Despite fire emissions being in many biomes of similar magnitude to that of Net Ecosystem Exchange, even the most complex Dynamic Vegetation Models (DVMs) embedded in IPCC General Circulation Models poorly represent fire behavior and dynamics, a fact which still remains understated. As DVMs operate on a deterministic, grid cell-by-grid cell basis they are unable to describe a host of important fire characteristics such as its propagation, magnitude of area burned and stochastic nature. Here we address these issues by describing a model-independent methodology which assimilates Earth Observation (EO) data by employing image analysis techniques and algorithms to offer a realistic fire disturbance regime in a DVM. This novel approach, with minimum model restructuring, manages to retain the Fire Return Interval produced by the model whilst assigning pragmatic characteristics to its fire outputs thus allowing realistic simulations of fire-related processes such as carbon injection into the atmosphere and permafrost degradation. We focus our simulations in the Arctic and specifically Canada and Russia and we offer a snippet of how this approach permits models to engage in post-fire dynamics hitherto absent from any other model regardless of complexity.

  13. Study on the effect of the operating condition on a pulverized coal-fired furnace using computational fluid dynamics commercial code

    SciTech Connect

    Manish Kumar; Santi Gopal Sahu . man_manna@yahoo.com

    2007-12-15

    Computer models for coal combustion are not sufficiently accurate to enable the design of pulverized coal fired furnaces or the selection of coal based on combustion behavior. Most comprehensive combustion models can predict with reasonable accuracy flow fields and heat transfer but usually with a much lesser degree of accuracy than the combustion of coal particles through char burnout. Computational fluid dynamics (CFD) modeling is recognized widely to be a cost-effective, advanced tool for optimizing the design and operating condition of the pulverized coal-fired furnaces for achieving cleaner and efficient power generation. Technologists and researchers are paying remarkable attention to CFD because of its value in the pulverized fuel fired furnace technology and its nonintrusiveness, sophistication, and ability to significantly reduce the time and expense involved in the design, optimization, trouble-shooting, and repair of power generation equipment. An attempt to study the effect of one of the operating conditions, i.e., burner tilts on coal combustion mechanisms, furnace exit gas temperature (FEGT), and heat flux distribution pattern, within the furnace has been made in this paper by modeling a 210 MW boiler using commercial CFD code FLUENT. 5 refs., 8 figs.

  14. Modeling of integrated environmental control systems for coal-fired power plants

    SciTech Connect

    Rubin, E.S.

    1989-10-01

    The general goal of this research project is to enhance, and transfer to DOE, a new computer simulation model for analyzing the performance and cost of environmental control systems for coal-fired power plants. Systems utilizing pre-combustion, combustion, or post-combustion control methods, individually or in combination, may be considered. A unique capability of this model is the probabilistic representation of uncertainty in model input parameters. This stochastic simulation capability allows the performance and cost of environmental control systems to be quantified probabilistically, accounting for the interactions among all uncertain process and economic parameters. This method facilitates more rigorous comparisons between conventional and advanced clean coal technologies promising improved cost and/or effectiveness for SO{sub 2} and NO{sub x} removal. Detailed modeling of several pre-combustion and post-combustion processes of interest to DOE/PETC have been selected for analysis as part of this project.

  15. Computational Model for Cell Morphodynamics

    NASA Astrophysics Data System (ADS)

    Shao, Danying; Rappel, Wouter-Jan; Levine, Herbert

    2010-09-01

    We develop a computational model, based on the phase-field method, for cell morphodynamics and apply it to fish keratocytes. Our model incorporates the membrane bending force and the surface tension and enforces a constant area. Furthermore, it implements a cross-linked actin filament field and an actin bundle field that are responsible for the protrusion and retraction forces, respectively. We show that our model predicts steady state cell shapes with a wide range of aspect ratios, depending on system parameters. Furthermore, we find that the dependence of the cell speed on this aspect ratio matches experimentally observed data.

  16. Modelling global computations with KLAIM.

    PubMed

    De Nicola, Rocco; Loreti, Michele

    2008-10-28

    A new area of research, known as Global Computing, is by now well established. It aims at defining new models of computation based on code and data mobility over wide-area networks with highly dynamic topologies, and at providing infrastructures to support coordination and control of components originating from different, possibly untrusted, fault-prone, malicious or selfish sources. In this paper, we present our contribution to the field of Global Computing that is centred on Kernel Language for Agents Interaction and Mobility (KLAIM). KLAIM is an experimental language specifically designed to programme distributed systems consisting of several mobile components that interact through multiple distributed tuple spaces. We present some of the key notions of the language and discuss how its formal semantics can be exploited to reason about qualitative and quantitative aspects of the specified systems.

  17. Radiative Transfer Modeling of a Large Pool Fire by Discrete Ordinates, Discrete Transfer, Ray Tracing, Monte Carlo and Moment Methods

    NASA Technical Reports Server (NTRS)

    Jensen, K. A.; Ripoll, J.-F.; Wray, A. A.; Joseph, D.; ElHafi, M.

    2004-01-01

    Five computational methods for solution of the radiative transfer equation in an absorbing-emitting and non-scattering gray medium were compared on a 2 m JP-8 pool fire. The temperature and absorption coefficient fields were taken from a synthetic fire due to the lack of a complete set of experimental data for fires of this size. These quantities were generated by a code that has been shown to agree well with the limited quantity of relevant data in the literature. Reference solutions to the governing equation were determined using the Monte Carlo method and a ray tracing scheme with high angular resolution. Solutions using the discrete transfer method, the discrete ordinate method (DOM) with both S(sub 4) and LC(sub 11) quadratures, and moment model using the M(sub 1) closure were compared to the reference solutions in both isotropic and anisotropic regions of the computational domain. DOM LC(sub 11) is shown to be the more accurate than the commonly used S(sub 4) quadrature technique, especially in anisotropic regions of the fire domain. This represents the first study where the M(sub 1) method was applied to a combustion problem occurring in a complex three-dimensional geometry. The M(sub 1) results agree well with other solution techniques, which is encouraging for future applications to similar problems since it is computationally the least expensive solution technique. Moreover, M(sub 1) results are comparable to DOM S(sub 4).

  18. Using the Cropland Data Layer to Develop Fire Fuels Maps for Fire Emissions Modeling in the Conterminous US

    NASA Astrophysics Data System (ADS)

    McCarty, J. L.; French, N. H.; Hamermesh, N.; Billmire, M.

    2011-12-01

    Spatial quantification of smoke emissions from biomass fires, including wildfire, prescribed fire, or cropland burning, requires information on the material burning. The type of biomass, also referred to as fuel, and the density of the biomass, known as fuel loading, are two factors considered when calculating the amount of biomass consumed and emissions released during a burn. For non-agricultural systems, fuel characteristics that influence fire conditions and emissions have been mapped across the US using the Fuel Characterization and Classification System (FCCS) developed at the US Forest Service's Pacific Northwest Research Station. FCCS information on fuel type and loading has been used in fire consumption and emissions models for several applications. We present new data on fuels for agricultural lands, including rangelands and croplands, not previously quantified within FCCS. These fuel descriptions are being integrated into the FCCS and mapped for the Conterminous US. We present a new set of maps of FCCS fuels for the Conterminous US that integrates croplands and other agricultural lands into the existing FCCS map. Cropland mapping is taken from the annual U.S. Department of Agriculture National Agricultural Statistics Service Cropland Data Layer. The annually updated FCCS map can be used to make spatially comprehensive estimates of fire emissions across the country for emissions inventories, pollution mapping, and carbon cycling studies.

  19. Calibrating a forest landscape model to simulate frequent fire in Mediterranean-type shrublands

    USGS Publications Warehouse

    Syphard, A.D.; Yang, J.; Franklin, J.; He, H.S.; Keeley, J.E.

    2007-01-01

    In Mediterranean-type ecosystems (MTEs), fire disturbance influences the distribution of most plant communities, and altered fire regimes may be more important than climate factors in shaping future MTE vegetation dynamics. Models that simulate the high-frequency fire and post-fire response strategies characteristic of these regions will be important tools for evaluating potential landscape change scenarios. However, few existing models have been designed to simulate these properties over long time frames and broad spatial scales. We refined a landscape disturbance and succession (LANDIS) model to operate on an annual time step and to simulate altered fire regimes in a southern California Mediterranean landscape. After developing a comprehensive set of spatial and non-spatial variables and parameters, we calibrated the model to simulate very high fire frequencies and evaluated the simulations under several parameter scenarios representing hypotheses about system dynamics. The goal was to ensure that observed model behavior would simulate the specified fire regime parameters, and that the predictions were reasonable based on current understanding of community dynamics in the region. After calibration, the two dominant plant functional types responded realistically to different fire regime scenarios. Therefore, this model offers a new alternative for simulating altered fire regimes in MTE landscapes. ?? 2007 Elsevier Ltd. All rights reserved.

  20. Forest fire effects on transpiration: process modeling of sapwood area reduction

    NASA Astrophysics Data System (ADS)

    Michaletz, Sean; Johnson, Edward

    2010-05-01

    Transpiration is a hydrological process that is strongly affected by forest fires. In crown fires, canopy fine fuels (foliage, buds, and small branches) combust, which kills individual trees and stops transpiration of the entire stand. In surface fires (intensities ≤ 2500 kW m-1), however, effects on transpiration are less predictable becuase heat transfer from the passing fireline can injure or kill fine roots, leaves, and sapwood; post-fire transpiration of forest stands is thus governed by fire effects on individual tree water budgets. Here, we consider fire effects on cross-sectional sapwood area. A two-dimensional model of transient bole heating is used to estimate radial isotherms for a range of fireline intensities typical of surface fires. Isotherms are then used to drive three processes by which heat may reduce sapwood area: 1) necrosis of living cells in contact with xylem conduits, which prevents repair of natural embolism; 2) relaxation of viscoelastic conduit wall polymers (cellulose, hemicelloluse, and lignin), which reduces cross-sectional conduit area; and 3) boiling of metastable water under tension, which causes conduit embolism. Results show that these processes operate on different time scales, suggesting that fire effects on transpiration vary with time since fire. The model can be linked with a three-dimensional physical fire spread model to predict size-dependent effects on individual trees, which can be used to estimate scaling of individual tree and stand-level transpiration.

  1. Multi-model estimates of fire emissions and air quality degradation in Southeast Asia

    NASA Astrophysics Data System (ADS)

    Marlier, M. E.; DeFries, R. S.; Kasibhatla, P. S.; Voulgarakis, A.; Kinney, P. L.; Shindell, D. T.; Randerson, J. T.

    2011-12-01

    Like fossil fuel pollution, fire emissions affect both climate change and air quality. In this study, we combine satellite-derived fire estimates and atmospheric modeling to quantify potential population exposure to particulate matter and ozone from fires in Southeast Asia from 1997 to 2007. This region has large interannual variability in fire activity due to El Niño-induced droughts and anthropogenic drivers. Though typically too wet to combust, increased sources of deforestation and degradation are enhancing the susceptibility of forests and underlying carbon-rich peat deposits to fire during drought, as documented in the extreme fires of the 1997-98 El Niño. Concerns of a positive feedback between fire activity and a warming climate would further increase the influence of fires on air quality degradation. Monthly fire emissions are estimated from the Global Fire Emissions Database (GFED version 3) and transported in two atmospheric models to assess population exposure. We show that during strong El Niño years, fires contribute to daily fine particulate matter and afternoon maximum ozone surface concentrations over 150 μg/m3 and 240 μg/m3, respectively. Exposure to these two types of pollutants increases mortality and hospital admissions from respiratory and cardiovascular diseases, even at low concentrations. This fire pollutant burden corresponds to 200 added days per year exceeding the World Health Organization fine particulate matter guideline and exposes up to 50 million additional people to more than 25 days above the most extreme pollutant concentrations. Our results indicate that substantial health and economic co-benefits would result from reducing fires in locations where transported emissions lead to enhanced exposure to air pollution during high fire years.

  2. Reconstruction of fire regimes through integrated paleoecological proxy data and ecological modeling

    PubMed Central

    Iglesias, Virginia; Yospin, Gabriel I.; Whitlock, Cathy

    2015-01-01

    Fire is a key ecological process affecting vegetation dynamics and land cover. The characteristic frequency, size, and intensity of fire are driven by interactions between top-down climate-driven and bottom-up fuel-related processes. Disentangling climatic from non-climatic drivers of past fire regimes is a grand challenge in Earth systems science, and a topic where both paleoecology and ecological modeling have made substantial contributions. In this manuscript, we (1) review the use of sedimentary charcoal as a fire proxy and the methods used in charcoal-based fire history reconstructions; (2) identify existing techniques for paleoecological modeling; and (3) evaluate opportunities for coupling of paleoecological and ecological modeling approaches to better understand the causes and consequences of past, present, and future fire activity. PMID:25657652

  3. Reconstruction of fire regimes through integrated paleoecological proxy data and ecological modeling.

    PubMed

    Iglesias, Virginia; Yospin, Gabriel I; Whitlock, Cathy

    2014-01-01

    Fire is a key ecological process affecting vegetation dynamics and land cover. The characteristic frequency, size, and intensity of fire are driven by interactions between top-down climate-driven and bottom-up fuel-related processes. Disentangling climatic from non-climatic drivers of past fire regimes is a grand challenge in Earth systems science, and a topic where both paleoecology and ecological modeling have made substantial contributions. In this manuscript, we (1) review the use of sedimentary charcoal as a fire proxy and the methods used in charcoal-based fire history reconstructions; (2) identify existing techniques for paleoecological modeling; and (3) evaluate opportunities for coupling of paleoecological and ecological modeling approaches to better understand the causes and consequences of past, present, and future fire activity.

  4. An experimental and modeling study of fires in ventilated ducts; Part 1: Liquid fuels

    SciTech Connect

    Comitis, S.C.; Glasser, D.; Young, B.D. . Dept. of Chemical Engineering)

    1994-03-01

    A theoretical model for fire propagation through a fuel-lined duct with a radially well-mixed axial flow is presented. The gas-phase is modeled as a steady-state process whereas the condensed-phase (fuel source) is taken to be the cause of transient fire propagation along the duct. Experiments were performed in a small-scale duct where fire propagation and gas temperature histories were acquired. Experimental results confirm hypotheses of pseudo-steady-state gas-phase processes. Theory and experiment display transient fire propagation for typical duct fire scenarios where initial fuel mass loading is constant with respect to duct length. The phenomena observed, as predicted by theory, is an initial jump'' of the fully developed combustion process followed by convergence to a steady-state constant fire propagation speed. The theory is in all important aspects able to quantitatively model the experimental results.

  5. Fire behavior modeling to assess net benefits of forest treatments on fire hazard mitigation and bioenergy production in Northeastern California

    Treesearch

    David J. Ganz; David S. Saah; Klaus Barber; Mark Nechodom

    2007-01-01

    The fire behavior modeling described here, conducted as part of the Biomass to Energy (B2E) life cycle assessment, is funded by the California Energy Commission to evaluate the potential net benefits associated with treating and utilizing forest biomass. The B2E project facilitates economic, environmental, energy, and effectiveness assessments of the potential public...

  6. Visualizing ultrasound through computational modeling

    NASA Technical Reports Server (NTRS)

    Guo, Theresa W.

    2004-01-01

    The Doppler Ultrasound Hematocrit Project (DHP) hopes to find non-invasive methods of determining a person s blood characteristics. Because of the limits of microgravity and the space travel environment, it is important to find non-invasive methods of evaluating the health of persons in space. Presently, there is no well developed method of determining blood composition non-invasively. This projects hopes to use ultrasound and Doppler signals to evaluate the characteristic of hematocrit, the percentage by volume of red blood cells within whole blood. These non-invasive techniques may also be developed to be used on earth for trauma patients where invasive measure might be detrimental. Computational modeling is a useful tool for collecting preliminary information and predictions for the laboratory research. We hope to find and develop a computer program that will be able to simulate the ultrasound signals the project will work with. Simulated models of test conditions will more easily show what might be expected from laboratory results thus help the research group make informed decisions before and during experimentation. There are several existing Matlab based computer programs available, designed to interpret and simulate ultrasound signals. These programs will be evaluated to find which is best suited for the project needs. The criteria of evaluation that will be used are 1) the program must be able to specify transducer properties and specify transmitting and receiving signals, 2) the program must be able to simulate ultrasound signals through different attenuating mediums, 3) the program must be able to process moving targets in order to simulate the Doppler effects that are associated with blood flow, 4) the program should be user friendly and adaptable to various models. After a computer program is chosen, two simulation models will be constructed. These models will simulate and interpret an RF data signal and a Doppler signal.

  7. Theory-Based Cartographic Risk Model Development and Application for Home Fire Safety.

    PubMed

    Furmanek, Stephen; Lehna, Carlee; Hanchette, Carol

    There is a gap in the use of predictive risk models to identify areas at risk for home fires and burn injury. The purpose of this study was to describe the creation, validation, and application of such a model using a sample from an intervention study with parents of newborns in Jefferson County, KY, as an example. Performed was a literature search to identify risk factors for home fires and burn injury in the target population. Obtained from the American Community Survey at the census tract level and synthesized to create a predictive cartographic risk model was risk factor data. Model validation was performed through correlation, regression, and Moran's I with fire incidence data from open records. Independent samples t-tests were used to examine the model in relation to geocoded participant addresses. Participant risk level for fire rate was determined and proximity to fire station service areas and hospitals. The model showed high and severe risk clustering in the northwest section of the county. Strongly correlated with fire rate was modeled risk; the best predictive model for fire risk contained home value (low), race (black), and non high school graduates. Applying the model to the intervention sample, the majority of participants were at lower risk and mostly within service areas closest to a fire department and hospital. Cartographic risk models were useful in identifying areas at risk and analyzing participant risk level. The methods outlined in this study are generalizable to other public health issues.

  8. Transition between Functional Regimes in an Integrate-And-Fire Network Model of the Thalamus

    PubMed Central

    Barardi, Alessandro; Mazzoni, Alberto

    2016-01-01

    The thalamus is a key brain element in the processing of sensory information. During the sleep and awake states, this brain area is characterized by the presence of two distinct dynamical regimes: in the sleep state activity is dominated by spindle oscillations (7 − 15 Hz) weakly affected by external stimuli, while in the awake state the activity is primarily driven by external stimuli. Here we develop a simple and computationally efficient model of the thalamus that exhibits two dynamical regimes with different information-processing capabilities, and study the transition between them. The network model includes glutamatergic thalamocortical (TC) relay neurons and GABAergic reticular (RE) neurons described by adaptive integrate-and-fire models in which spikes are induced by either depolarization or hyperpolarization rebound. We found a range of connectivity conditions under which the thalamic network composed by these neurons displays the two aforementioned dynamical regimes. Our results show that TC-RE loops generate spindle-like oscillations and that a minimum level of clustering (i.e. local connectivity density) in the RE-RE connections is necessary for the coexistence of the two regimes. We also observe that the transition between the two regimes occurs when the external excitatory input on TC neurons (mimicking sensory stimulation) is large enough to cause a significant fraction of them to switch from hyperpolarization-rebound-driven firing to depolarization-driven firing. Overall, our model gives a novel and clear description of the role that the two types of neurons and their connectivity play in the dynamical regimes observed in the thalamus, and in the transition between them. These results pave the way for the development of efficient models of the transmission of sensory information from periphery to cortex. PMID:27598260

  9. Transition between Functional Regimes in an Integrate-And-Fire Network Model of the Thalamus.

    PubMed

    Barardi, Alessandro; Garcia-Ojalvo, Jordi; Mazzoni, Alberto

    2016-01-01

    The thalamus is a key brain element in the processing of sensory information. During the sleep and awake states, this brain area is characterized by the presence of two distinct dynamical regimes: in the sleep state activity is dominated by spindle oscillations (7 - 15 Hz) weakly affected by external stimuli, while in the awake state the activity is primarily driven by external stimuli. Here we develop a simple and computationally efficient model of the thalamus that exhibits two dynamical regimes with different information-processing capabilities, and study the transition between them. The network model includes glutamatergic thalamocortical (TC) relay neurons and GABAergic reticular (RE) neurons described by adaptive integrate-and-fire models in which spikes are induced by either depolarization or hyperpolarization rebound. We found a range of connectivity conditions under which the thalamic network composed by these neurons displays the two aforementioned dynamical regimes. Our results show that TC-RE loops generate spindle-like oscillations and that a minimum level of clustering (i.e. local connectivity density) in the RE-RE connections is necessary for the coexistence of the two regimes. We also observe that the transition between the two regimes occurs when the external excitatory input on TC neurons (mimicking sensory stimulation) is large enough to cause a significant fraction of them to switch from hyperpolarization-rebound-driven firing to depolarization-driven firing. Overall, our model gives a novel and clear description of the role that the two types of neurons and their connectivity play in the dynamical regimes observed in the thalamus, and in the transition between them. These results pave the way for the development of efficient models of the transmission of sensory information from periphery to cortex.

  10. Parallel computing in enterprise modeling.

    SciTech Connect

    Goldsby, Michael E.; Armstrong, Robert C.; Shneider, Max S.; Vanderveen, Keith; Ray, Jaideep; Heath, Zach; Allan, Benjamin A.

    2008-08-01

    This report presents the results of our efforts to apply high-performance computing to entity-based simulations with a multi-use plugin for parallel computing. We use the term 'Entity-based simulation' to describe a class of simulation which includes both discrete event simulation and agent based simulation. What simulations of this class share, and what differs from more traditional models, is that the result sought is emergent from a large number of contributing entities. Logistic, economic and social simulations are members of this class where things or people are organized or self-organize to produce a solution. Entity-based problems never have an a priori ergodic principle that will greatly simplify calculations. Because the results of entity-based simulations can only be realized at scale, scalable computing is de rigueur for large problems. Having said that, the absence of a spatial organizing principal makes the decomposition of the problem onto processors problematic. In addition, practitioners in this domain commonly use the Java programming language which presents its own problems in a high-performance setting. The plugin we have developed, called the Parallel Particle Data Model, overcomes both of these obstacles and is now being used by two Sandia frameworks: the Decision Analysis Center, and the Seldon social simulation facility. While the ability to engage U.S.-sized problems is now available to the Decision Analysis Center, this plugin is central to the success of Seldon. Because Seldon relies on computationally intensive cognitive sub-models, this work is necessary to achieve the scale necessary for realistic results. With the recent upheavals in the financial markets, and the inscrutability of terrorist activity, this simulation domain will likely need a capability with ever greater fidelity. High-performance computing will play an important part in enabling that greater fidelity.

  11. Cosmic logic: a computational model

    SciTech Connect

    Vanchurin, Vitaly

    2016-02-01

    We initiate a formal study of logical inferences in context of the measure problem in cosmology or what we call cosmic logic. We describe a simple computational model of cosmic logic suitable for analysis of, for example, discretized cosmological systems. The construction is based on a particular model of computation, developed by Alan Turing, with cosmic observers (CO), cosmic measures (CM) and cosmic symmetries (CS) described by Turing machines. CO machines always start with a blank tape and CM machines take CO's Turing number (also known as description number or Gödel number) as input and output the corresponding probability. Similarly, CS machines take CO's Turing number as input, but output either one if the CO machines are in the same equivalence class or zero otherwise. We argue that CS machines are more fundamental than CM machines and, thus, should be used as building blocks in constructing CM machines. We prove the non-computability of a CS machine which discriminates between two classes of CO machines: mortal that halts in finite time and immortal that runs forever. In context of eternal inflation this result implies that it is impossible to construct CM machines to compute probabilities on the set of all CO machines using cut-off prescriptions. The cut-off measures can still be used if the set is reduced to include only machines which halt after a finite and predetermined number of steps.

  12. Minimal Models of Multidimensional Computations

    PubMed Central

    Fitzgerald, Jeffrey D.; Sincich, Lawrence C.; Sharpee, Tatyana O.

    2011-01-01

    The multidimensional computations performed by many biological systems are often characterized with limited information about the correlations between inputs and outputs. Given this limitation, our approach is to construct the maximum noise entropy response function of the system, leading to a closed-form and minimally biased model consistent with a given set of constraints on the input/output moments; the result is equivalent to conditional random field models from machine learning. For systems with binary outputs, such as neurons encoding sensory stimuli, the maximum noise entropy models are logistic functions whose arguments depend on the constraints. A constraint on the average output turns the binary maximum noise entropy models into minimum mutual information models, allowing for the calculation of the information content of the constraints and an information theoretic characterization of the system's computations. We use this approach to analyze the nonlinear input/output functions in macaque retina and thalamus; although these systems have been previously shown to be responsive to two input dimensions, the functional form of the response function in this reduced space had not been unambiguously identified. A second order model based on the logistic function is found to be both necessary and sufficient to accurately describe the neural responses to naturalistic stimuli, accounting for an average of 93% of the mutual information with a small number of parameters. Thus, despite the fact that the stimulus is highly non-Gaussian, the vast majority of the information in the neural responses is related to first and second order correlations. Our results suggest a principled and unbiased way to model multidimensional computations and determine the statistics of the inputs that are being encoded in the outputs. PMID:21455284

  13. Modeling the Effect of Climate Change on Large Fire Size, Counts, and Intensities Using the Large Fire Simulator (FSim)

    NASA Astrophysics Data System (ADS)

    Riley, K. L.; Haas, J. R.; Finney, M.; Abatzoglou, J. T.

    2013-12-01

    Changes in climate can be expected to cause changes in wildfire activity due to a combination of shifts in weather (temperature, precipitation, relative humidity, wind speed and direction) and vegetation. Changes in vegetation could include type conversions, altered forest structure, and shifts in species composition, the effects of which could be mitigated or exacerbated by management activities. Further, changes in suppression response and effectiveness may alter potential wildfire activity, as well as the consequences of wildfire. Feedbacks among these factors are extremely complex and uncertain. The ability to anticipate changes driven by fire weather (largely outside of human control) can lead to development of fire and fuel management strategies aimed at mitigating current and future risk. Therefore, in this study we focus on isolating the effects of climate-induced changes in weather on wildfire activity. Specifically, we investigated the effect of changes in weather on fire activity in the Canadian Rockies ecoregion, which encompasses Glacier National Park and several large wilderness areas to the south. To model the ignition, growth, and containment of wildfires, we used the Large Fire Simulator (FSim), which we coupled with current and projected future climatic conditions. Weather streams were based on data from 14 downscaled Global Circulation Models (GCMs) from the Coupled Model Intercomparison Project Phase 5 (CMIP5) using the Representative Concentration Pathways (RCP) 45 and 85 for the years 2040-2060. While all GCMs indicate increases in temperature for this area, which would be expected to exacerbate fire activity, precipitation predictions for the summer wildfire season are more variable, ranging from a decrease of approximately 50 mm to an increase of approximately 50 mm. Windspeeds are generally predicted to decrease, which would reduce rates of spread and fire intensity. The net effect of these weather changes on the size, number, and intensity

  14. On wildfire complexity, simple models and environmental templates for fire size distributions

    NASA Astrophysics Data System (ADS)

    Boer, M. M.; Bradstock, R.; Gill, M.; Sadler, R.

    2012-12-01

    Vegetation fires affect some 370 Mha annually. At global and continental scales, fire activity follows predictable spatiotemporal patterns driven by gradients and seasonal fluctuations of primary productivity and evaporative demand that set constraints for fuel accumulation rates and fuel dryness, two key ingredients of fire. At regional scales, fires are also known to affect some landscapes more than others and within landscapes to occur preferentially in some sectors (e.g. wind-swept ridges) and rarely in others (e.g. wet gullies). Another common observation is that small fires occur relatively frequent yet collectively burn far less country than relatively infrequent large fires. These patterns of fire activity are well known to management agencies and consistent with their (informal) models of how the basic drivers and constraints of fire (i.e. fuels, ignitions, weather) vary in time and space across the landscape. The statistical behaviour of these landscape fire patterns has excited the (academic) research community by showing some consistency with that of complex dynamical systems poised at a phase transition. The common finding that the frequency-size distributions of actual fires follow power laws that resemble those produced by simple cellular models from statistical mechanics has been interpreted as evidence that flammable landscapes operate as self-organising systems with scale invariant fire size distributions emerging 'spontaneously' from simple rules of contagious fire spread and a strong feedback between fires and fuel patterns. In this paper we argue that the resemblance of simulated and actual fire size distributions is an example of equifinality, that is fires in model landscapes and actual landscapes may show similar statistical behaviour but this is reached by qualitatively different pathways or controlling mechanisms. We support this claim with two key findings regarding simulated fire spread mechanisms and fire-fuel feedbacks. Firstly, we

  15. Computational Models of Rock Failure

    NASA Astrophysics Data System (ADS)

    May, Dave A.; Spiegelman, Marc

    2017-04-01

    Practitioners in computational geodynamics, as per many other branches of applied science, typically do not analyse the underlying PDE's being solved in order to establish the existence or uniqueness of solutions. Rather, such proofs are left to the mathematicians, and all too frequently these results lag far behind (in time) the applied research being conducted, are often unintelligible to the non-specialist, are buried in journals applied scientists simply do not read, or simply have not been proven. As practitioners, we are by definition pragmatic. Thus, rather than first analysing our PDE's, we first attempt to find approximate solutions by throwing all our computational methods and machinery at the given problem and hoping for the best. Typically this approach leads to a satisfactory outcome. Usually it is only if the numerical solutions "look odd" that we start delving deeper into the math. In this presentation I summarise our findings in relation to using pressure dependent (Drucker-Prager type) flow laws in a simplified model of continental extension in which the material is assumed to be an incompressible, highly viscous fluid. Such assumptions represent the current mainstream adopted in computational studies of mantle and lithosphere deformation within our community. In short, we conclude that for the parameter range of cohesion and friction angle relevant to studying rocks, the incompressibility constraint combined with a Drucker-Prager flow law can result in problems which have no solution. This is proven by a 1D analytic model and convincingly demonstrated by 2D numerical simulations. To date, we do not have a robust "fix" for this fundamental problem. The intent of this submission is to highlight the importance of simple analytic models, highlight some of the dangers / risks of interpreting numerical solutions without understanding the properties of the PDE we solved, and lastly to stimulate discussions to develop an improved computational model of

  16. Assessing accuracy of a probabilistic model for very large fire in the Rocky Mountains: A High Park Fire case study

    NASA Astrophysics Data System (ADS)

    Stavros, E.; Abatzoglou, J. T.; Larkin, N.; McKenzie, D.; Steel, A.

    2012-12-01

    Across the western United States, the largest wildfires account for a major proportion of the area burned and substantially affect mountain forests and their associated ecosystem services, among which is pristine air quality. These fires commandeer national attention and significant fire suppression resources. Despite efforts to understand the influence of fuel loading, climate, and weather on annual area burned, few studies have focused on understanding what abiotic factors enable and drive the very largest wildfires. We investigated the correlation between both antecedent climate and in-situ biophysical variables and very large (>20,000 ha) fires in the western United States from 1984 to 2009. We built logistic regression models, at the spatial scale of the national Geographic Area Coordination Centers (GACCs), to estimate the probability that a given day is conducive to a very large wildfire. Models vary in accuracy and in which variables are the best predictors. In a case study of the conditions of the High Park Fire, neighboring Fort Collins, Colorado, occurring in early summer 2012, we evaluate the predictive accuracy of the Rocky Mountain model.

  17. Technologies of Physical Monitoring and Mathematical Modeling for Estimation of Ground Forest Fuel Fire Condition

    NASA Astrophysics Data System (ADS)

    Baranovskiy, Nikolay V.; Bazarov, Alexandr V.

    2016-02-01

    Description of new experimental installations for the control of parameters of environment with a view of monitoring of forest fires presented in article. Stationary and mobile variants developed. Typical results of operation of installations during a fire-dangerous season of 2015 in vicinities of Ulan-Ude (Republic Buryatiya, Russia) presented. One-dimensional mathematical model of forest fuel drying which can be used for monitoring of forest fire danger with attraction of environmental parameters data during fire-dangerous season offered. Verification of mathematical model with use of known experimental data spent.

  18. Dynamic modeling of a single-stage downward firing, entrained flow gasifier

    SciTech Connect

    Kasule, J., Turton, R., Bhattacharyya, D., Zitney, S.

    2012-01-01

    The gasifier is the heart of the integrated gasification combined cycle (IGCC), a technology that has emerged as an attractive alternative to conventional coal-fired power plant technology due to its higher efficiency and cleaner environmental performance especially with the option of CO{sub 2} capture and sequestration. Understanding the optimal performance of the gasifier is therefore paramount for the efficient operation of IGCC power plants. Numerous gasifier models of varying complexity have been developed to study the various aspects of gasifier performance. These range from simple one-dimensional (1D) process-type models to rigorous higher order 2-3D models based on computational fluid dynamics (CFD). Whereas high-fidelity CFD models can accurately predict most key aspects of gasifier performance, they are computationally expensive and typically take hours to days to execute on high-performance computers. Therefore, faster 1D partial differential equation (PDE)-based models are required for use in dynamic simulation studies, control system analysis, and training applications. A number of 1D gasifier models can be found in the literature, but most are steady-state models that have limited application in the practical operation of the gasifier. As a result, 1D PDE-based dynamic models are needed to further study and predict gasifier performance under a wide variety of process conditions and disturbances. In the current study, a 1D transient model of a single-stage downward-fired GE/Texaco-type entrained-flow gasifier has been developed. The model comprises mass, momentum and energy balances for the gas and solid phases. The model considers the initial gasification processes of water evaporation and coal devolatilization. In addition, the key heterogeneous and homogeneous chemical reactions have been modeled. The resulting time-dependent PDE model is solved using the well-known method of lines approach in Aspen Custom Modeler®, whereby the PDEs in the spatial

  19. A model of gas mixing into single-entrance tree cavities during wildland fires

    Treesearch

    A.S. Bova; G. Bohrer; Matthew Dickinson

    2011-01-01

    The level of protection to fauna provided by tree cavities during wildland fires is not well understood. Here we present a model for estimating the transport of combustion gases into cylindrical, single-entrance cavities during exposures caused by different wildland fire scenarios. In these shelters, the entrance occurs near the top of the cavity. This empirical model...

  20. Evaluating crown fire rate of spread predictions from physics-based models

    Treesearch

    C. M. Hoffman; J. Ziegler; J. Canfield; R. R. Linn; W. Mell; C. H. Sieg; F. Pimont

    2015-01-01

    Modeling the behavior of crown fires is challenging due to the complex set of coupled processes that drive the characteristics of a spreading wildfire and the large range of spatial and temporal scales over which these processes occur. Detailed physics-based modeling approaches such as FIRETEC and the Wildland Urban Interface Fire Dynamics Simulator (WFDS) simulate...

  1. Tree injury and mortality in fires: developing process-based models

    Treesearch

    Bret W. Butler; Matthew B. Dickinson

    2010-01-01

    Wildland fire managers are often required to predict tree injury and mortality when planning a prescribed burn or when considering wildfire management options; and, currently, statistical models based on post-fire observations are the only tools available for this purpose. Implicit in the derivation of statistical models is the assumption that they are strictly...

  2. Computational Models of Cognitive Control

    PubMed Central

    O’Reilly, Randall C.; Herd, Seth A.; Pauli, Wolfgang M.

    2010-01-01

    Cognitive control refers to the ability to perform task-relevant processing in the face of other distractions or other forms of interference, in the absence of strong environmental support. It depends on the integrity of the prefrontal cortex and associated biological structures (e.g., the basal ganglia). Computational models have played an influential role in developing our understanding of this system, and we review current developments in three major areas: dynamic gating of prefrontal representations, hierarchies in the prefrontal cortex, and reward, motivation, and goal-related processing in prefrontal cortex. Models in these and other areas are advancing the field further forward. PMID:20185294

  3. FIRES: Fire Information Retrieval and Evaluation System - A program for fire danger rating analysis

    Treesearch

    Patricia L. Andrews; Larry S. Bradshaw

    1997-01-01

    A computer program, FIRES: Fire Information Retrieval and Evaluation System, provides methods for evaluating the performance of fire danger rating indexes. The relationship between fire danger indexes and historical fire occurrence and size is examined through logistic regression and percentiles. Historical seasonal trends of fire danger and fire occurrence can be...

  4. Transparency of Computational Intelligence Models

    NASA Astrophysics Data System (ADS)

    Owotoki, Peter; Mayer-Lindenberg, Friedrich

    This paper introduces the behaviour of transparency of computational intelligence (CI) models. Transparency reveals to end users the underlying reasoning process of the agent embodying CI models. This is of great benefit in applications (e.g. data mining, entertainment and personal robotics) with humans as end users because it increases their trust in the decisions of the agent and their acceptance of its results. Our integrated approach, wherein rules are just one of other transparency factors (TF), differs from previous related efforts which have focused mostly on generation of comprehensible rules as explanations. Other TF include degree of confidence measure and visualization of principal features. The transparency quotient is introduced as a measure of the transparency of models based on these factors. The transparency enabled generalized exemplar model has been developed to demonstrate the TF and transparency concepts introduced in this paper.

  5. Workshop on Computational Turbulence Modeling

    NASA Technical Reports Server (NTRS)

    Shabbir, A. (Compiler); Shih, T.-H. (Compiler); Povinelli, L. A. (Compiler)

    1994-01-01

    The purpose of this meeting was to discuss the current status and future development of turbulence modeling in computational fluid dynamics for aerospace propulsion systems. Various turbulence models have been developed and applied to different turbulent flows over the past several decades and it is becoming more and more urgent to assess their performance in various complex situations. In order to help users in selecting and implementing appropriate models in their engineering calculations, it is important to identify the capabilities as well as the deficiencies of these models. This also benefits turbulence modelers by permitting them to further improve upon the existing models. This workshop was designed for exchanging ideas and enhancing collaboration between different groups in the Lewis community who are using turbulence models in propulsion related CFD. In this respect this workshop will help the Lewis goal of excelling in propulsion related research. This meeting had seven sessions for presentations and one panel discussion over a period of two days. Each presentation session was assigned to one or two branches (or groups) to present their turbulence related research work. Each group was asked to address at least the following points: current status of turbulence model applications and developments in the research; progress and existing problems; and requests about turbulence modeling. The panel discussion session was designed for organizing committee members to answer management and technical questions from the audience and to make concluding remarks.

  6. Fire dynamics during the 20th century simulated by the Community Land Model

    SciTech Connect

    Kloster, Silvia; Mahowald, Natalie; Randerson, Jim; Thornton, Peter E; Hoffman, Forrest M; Levis, Sam; Lawrence, Peter J.; Feddema, Johan J.; Oleson, Keith; Lawrence, David M.

    2011-01-01

    Fire is an integral Earth System process that interacts with climate in multiple ways. Here we assessed the parametrization of fires in the Community Land Model (CLM-CN) and improved the ability of the model to reproduce contemporary global patterns of burned areas and fire emissions. In addition to wildfires we extended CLM-CN to account for fires related to deforestation. We compared contemporary fire carbon emissions predicted by the model to satellite-based estimates in terms of magnitude and spatial extent as well as interannual and seasonal variability. Long-term trends during the 20th century were compared with historical estimates. Overall we found the best agreement between simulation and observations for the fire parametrization based on the work by Arora and Boer (2005). We obtained substantial improvement when we explicitly considered human caused ignition and fire suppression as a function of population density. Simulated fire carbon emissions ranged between 2.0 and 2.4 Pg C/year for the period 1997 2004. Regionally the simulations had a low bias over Africa and a high bias over South America when compared to satellite-based products. The net terrestrial carbon source due to land use change for the 1990s was 1.2 Pg C/year with 11% stemming from deforestation fires. During 2000 2004 this flux decreased to 0.85 Pg C/year with a similar relative contribution from deforestation fires. Between 1900 and 1960 we predicted a slight downward trend in global fire emissions caused by reduced fuels as a consequence of wood harvesting and also by increases in fire suppression. The model predicted an upward trend during the last three decades of the 20th century as a result of climate variations and large burning events associated with ENSO-induced drought conditions.

  7. Modelling Middle Infrared Thermal Imagery from Observed or Simulated Active Fire

    NASA Astrophysics Data System (ADS)

    Paugam, R.; Gastellu-Etchegorry, J. P.; Mell, W.; Johnston, J.; Filippi, J. B.

    2016-12-01

    The Fire Radiative Power (FRP) is used in the atmospheric and fire communities to estimate fire emission. For example, the current version of the emission inventory GFAS is using FRP observation from the MODIS sensors to derive daily global distribution of fire emissions. Although the FRP product is widely accepted, most of its theoretical justifications are still based on small scale burns. When up-scaling to large fires effects of view angle, canopy cover, or smoke absorption are still unknown. To cover those questions, we are building a system based on the DART radiative transfer model to simulate the middle infrared radiance emitted by a propagating fire front and propagating in the surrounding scene made of ambient vegetation and plume aerosols. The current version of the system was applied to fire ranging from a 1m2 to 7ha. The 3D fire scene used as input in DART is made of the flame, the vegetation (burnt and unburnt), and the plume. It can be either set up from [i] 3D physical based model scene (ie WFDS, mainly applicable for small scale burn), [ii] coupled 2D fire spread - atmospheric models outputs (eg ForeFire-MesoNH) or [iii] derived from thermal imageries observations (here plume effects are not considered). In the last two cases, as the complexity of physical processes occurring in the flame (in particular soot formation and emission) is not to solved, the flames structures are parameterized with (a) temperature and soot concentration based on empirical derived profiles and (b) 3D triangular shape hull interpolated at the fire front location. Once the 3D fire scene is set up, DART is then used to render thermal imageries in the middle infrared. Using data collected from burns conducted at different scale, the modelled thermal imageries are compared against observations, and effects of view angle are discussed.

  8. Fire, ice, water, and dirt: A simple climate model.

    PubMed

    Kroll, John

    2017-07-01

    A simple paleoclimate model was developed as a modeling exercise. The model is a lumped parameter system consisting of an ocean (water), land (dirt), glacier, and sea ice (ice) and driven by the sun (fire). In comparison with other such models, its uniqueness lies in its relative simplicity yet yielding good results. For nominal values of parameters, the system is very sensitive to small changes in the parameters, yielding equilibrium, steady oscillations, and catastrophes such as freezing or boiling oceans. However, stable solutions can be found, especially naturally oscillating solutions. For nominally realistic conditions, natural periods of order 100kyrs are obtained, and chaos ensues if the Milankovitch orbital forcing is applied. An analysis of a truncated system shows that the naturally oscillating solution is a limit cycle with the characteristics of a relaxation oscillation in the two major dependent variables, the ocean temperature and the glacier ice extent. The key to getting oscillations is having the effective emissivity decreasing with temperature and, at the same time, the effective ocean albedo decreases with increasing glacier extent. Results of the original model compare favorably to the proxy data for ice mass variation, but not for temperature variation. However, modifications to the effective emissivity and albedo can be made to yield much more realistic results. The primary conclusion is that the opinion of Saltzman [Clim. Dyn. 5, 67-78 (1990)] is plausible that the external Milankovitch orbital forcing is not sufficient to explain the dominant 100kyr period in the data.

  9. Fire, ice, water, and dirt: A simple climate model

    NASA Astrophysics Data System (ADS)

    Kroll, John

    2017-07-01

    A simple paleoclimate model was developed as a modeling exercise. The model is a lumped parameter system consisting of an ocean (water), land (dirt), glacier, and sea ice (ice) and driven by the sun (fire). In comparison with other such models, its uniqueness lies in its relative simplicity yet yielding good results. For nominal values of parameters, the system is very sensitive to small changes in the parameters, yielding equilibrium, steady oscillations, and catastrophes such as freezing or boiling oceans. However, stable solutions can be found, especially naturally oscillating solutions. For nominally realistic conditions, natural periods of order 100kyrs are obtained, and chaos ensues if the Milankovitch orbital forcing is applied. An analysis of a truncated system shows that the naturally oscillating solution is a limit cycle with the characteristics of a relaxation oscillation in the two major dependent variables, the ocean temperature and the glacier ice extent. The key to getting oscillations is having the effective emissivity decreasing with temperature and, at the same time, the effective ocean albedo decreases with increasing glacier extent. Results of the original model compare favorably to the proxy data for ice mass variation, but not for temperature variation. However, modifications to the effective emissivity and albedo can be made to yield much more realistic results. The primary conclusion is that the opinion of Saltzman [Clim. Dyn. 5, 67-78 (1990)] is plausible that the external Milankovitch orbital forcing is not sufficient to explain the dominant 100kyr period in the data.

  10. The effectiveness and limitations of fuel modeling using the fire and fuels extension to the Forest Vegetation Simulator

    Treesearch

    Erin K. Noonan-Wright; Nicole M. Vaillant; Alicia L. Reiner

    2014-01-01

    Fuel treatment effectiveness is often evaluated with fire behavior modeling systems that use fuel models to generate fire behavior outputs. How surface fuels are assigned, either using one of the 53 stylized fuel models or developing custom fuel models, can affect predicted fire behavior. We collected surface and canopy fuels data before and 1, 2, 5, and 8 years after...

  11. Modeling tree-level fuel connectivity to evaluate the effectiveness of thinning treatments for reducing crown fire potential

    Treesearch

    Marco A. Contreras; Russell A. Parsons; Woodam Chung

    2012-01-01

    Land managers have been using fire behavior and simulation models to assist in several fire management tasks. These widely-used models use average attributes to make stand-level predictions without considering spatial variability of fuels within a stand. Consequently, as the existing models have limitations in adequately modeling crown fire initiation and propagation,...

  12. Dynamics of the exponential integrate-and-fire model with slow currents and adaptation.

    PubMed

    Barranca, Victor J; Johnson, Daniel C; Moyher, Jennifer L; Sauppe, Joshua P; Shkarayev, Maxim S; Kovačič, Gregor; Cai, David

    2014-08-01

    In order to properly capture spike-frequency adaptation with a simplified point-neuron model, we study approximations of Hodgkin-Huxley (HH) models including slow currents by exponential integrate-and-fire (EIF) models that incorporate the same types of currents. We optimize the parameters of the EIF models under the external drive consisting of AMPA-type conductance pulses using the current-voltage curves and the van Rossum metric to best capture the subthreshold membrane potential, firing rate, and jump size of the slow current at the neuron's spike times. Our numerical simulations demonstrate that, in addition to these quantities, the approximate EIF-type models faithfully reproduce bifurcation properties of the HH neurons with slow currents, which include spike-frequency adaptation, phase-response curves, critical exponents at the transition between a finite and infinite number of spikes with increasing constant external drive, and bifurcation diagrams of interspike intervals in time-periodically forced models. Dynamics of networks of HH neurons with slow currents can also be approximated by corresponding EIF-type networks, with the approximation being at least statistically accurate over a broad range of Poisson rates of the external drive. For the form of external drive resembling realistic, AMPA-like synaptic conductance response to incoming action potentials, the EIF model affords great savings of computation time as compared with the corresponding HH-type model. Our work shows that the EIF model with additional slow currents is well suited for use in large-scale, point-neuron models in which spike-frequency adaptation is important.

  13. Impacts of Boreal Forest Fires and Post-Fire Succession on Energy Budgets and Climate in the Community Earth System Model

    NASA Astrophysics Data System (ADS)

    Rogers, B. M.; Randerson, J. T.; Bonan, G. B.

    2011-12-01

    Vegetation compositions of boreal forests are determined largely by recovery patterns after large-scale disturbances, the most notable of which is wildfire. Forest compositions exert large controls on regional energy and greenhouse gas budgets by affecting surface albedo, net radiation, turbulent energy fluxes, and carbon stocks. Impacts of boreal forest fires on climate are therefore products of direct fire effects, including charred surfaces and emitted aerosols and greenhouse gasses, and post-fire vegetation succession, which affects carbon and energy exchange for many decades after the initial disturbance. Climate changes are expected to be greatest at high latitudes, leading many to project increases in boreal forest fires. While numerous studies have documented the effects of post-fire landscape on energy and gas budgets in boreal forests, to date no continental analysis using a coupled model has been performed. In this study we quantified the effects of boreal forest fires and post-fire succession on regional and global climate using model experiments in the Community Earth System Model. We used 20th century climate data and MODIS vegetation continuous fields and land cover classes to identify boreal forests across North America and Eurasia. Historical fire return intervals were derived from a regression approach utilizing the Canadian and Alaskan Large Fire Databases, the Global Fire Emissions Database v3, and land cover and climate data. Succession trajectories were derived from the literature and MODIS land cover over known fire scars. Major improvements in model-data comparisons of long-term energy budgets were observed by prescribing post-fire vegetation succession. Global simulations using historical and future burn area scenarios highlight the potential impacts on climate from changing fire regimes and provide motivation for including vegetation succession in coupled simulations.

  14. Historical and future fire occurrence (1850 to 2100) simulated in CMIP5 Earth System Models

    NASA Astrophysics Data System (ADS)

    Kloster, Silvia; Lasslop, Gitta

    2017-03-01

    Earth System Models (ESMs) have recently integrated fire processes in their vegetation model components to account for fire as an important disturbance process for vegetation dynamics and agent in the land carbon cycle. The present study analyses the performance of ESMs that participated in the 5th Coupled Model Intercomparison Project (CMIP5) in simulating historical and future fire occurrence. The global present day (1981 to 2005) burned area simulated in the analysed ESMs ranges between 149 and 208Mha, which is substantially lower than the most recent observation based estimate of 399Mha (GFEDv4s averaged over the time period 1997 to 2015). Simulated global fire carbon emissions, however, are with 2.0PgC/year to 2.7PgC/year on the higher end compared to the GFEDv4s estimate of 2.2PgC/year. Regionally, largest differences are found for Africa. Over the historical period (1850 to 2005) changes in simulated fire carbon emissions range between an increase of +43% and a decrease of -35%. For the future (2005 to 2100) we analysed the CMIP5 simulations following the representative concentration pathways (RCPs) 26, 45, and 85, for which the strongest changes in global fire carbon emissions simulated in the single ESMs amount to +8%, +52% and +58%, respectively. Overall, however, there is little agreement between the single ESMs on how fire occurrence changed over the past or will change in the future. Furthermore, contrasting simulated changes in fire carbon emissions and changes in annual mean precipitation shows no emergent pattern among the different analysed ESMs on the regional or global scale. This indicates differences in the single fire model representations that should be subject of upcoming fire model intercomparison studies. The increasing information derived from observational datasets (charcoal, ice-cores, satellite, inventories) will help to further constrain the trajectories of fire models.

  15. A stochastic Forest Fire Model for future land cover scenarios assessment

    NASA Astrophysics Data System (ADS)

    Fiorucci, P.; Holmes, T.; Gaetani, F.; D'Andrea, M.

    2009-04-01

    Land cover change and forest fire interaction under climate and socio-economics changes, is one of the main issues of the 21th century. The capability of defining future scenarios of land cover and fire regime allow forest managers to better understand the best actions to be carried out and their long term effects. In this paper a new methodology for land cover change simulations under climate change and fire disturbance is presented and discussed. The methodology is based on the assumption that forest fires exhibits power law frequency-area distribution. The well known Forest Fire Model (FFM), which is an example of self organized criticality, is able to reproduce this behavior. Starting from this observation, a modified version of the FFM has been developed. The new model, called Modified Forest Fire Model (MFFM) introduces several new features. A stochastic model for vegetation growth and regrowth after fire occurrence has been implemented for different kind of vegetations. In addition, a stochastic fire propagation model taking into account topography and vegetation cover has been introduced. The MFFM has been developed with the purpose of estimating vegetation cover changes and fire regimes over a time windows of many years for a given spatial region. Two different case studies have been carried out. The first case study is related with Liguria (Italy), a region of 5400 km2 lying between the Cote d'Azur, France, and Tuscany, Italy, on the northwest coast of the Tyrrhenian Sea. This region is characterized by Mediterranean fire regime. The second case study has been carried out in California (Florida) on a region having similar area and characterized by similar climate conditions. In both cases the model well represents the actual fire regime in terms of power law parameters proving interesting results about future land cover scenarios under climate, land use and socio-economics change.

  16. Simulating the Effects of Fire on Forests in the Russian Far East: Integrating a Fire Danger Model and the FAREAST Forest Growth Model Across a Complex Landscape

    NASA Astrophysics Data System (ADS)

    Sherman, N. J.; Loboda, T.; Sun, G.; Shugart, H. H.; Csiszar, I.

    2008-12-01

    The remaining natural habitat of the critically endangered Amur tiger (Panthera tigris altaica) and Amur leopard (Panthera pardus orientalis) is a vast, biologically and topographically diverse area in the Russian Far East (RFE). Although wildland fire is a natural component of ecosystem functioning in the RFE, severe or repeated fires frequently re-set the process of forest succession, which may take centuries to return the affected forests to the pre-fire state and thus significantly alters habitat quality and long-term availability. The frequency of severe fire events has increased over the last 25 years, leading to irreversible modifications of some parts of the species' habitats. Moreover, fire regimes are expected to continue to change toward more frequent and severe events under the influence of climate change. Here we present an approach to developing capabilities for a comprehensive assessment of potential Amur tiger and leopard habitat availability throughout the 21st century by integrating regionally parameterized fire danger and forest growth models. The FAREAST model is an individual, gap-based model that simulates forest growth in a single location and demonstrates temporally explicit forest succession leading to mature forests. Including spatially explicit information on probabilities of fire occurrence at 1 km resolution developed from the regionally specific remotely -sensed data-driven fire danger model improves our ability to provide realistic long-term projections of potential forest composition in the RFE. This work presents the first attempt to merge the FAREAST model with a fire disturbance model, to validate its outputs across a large region, and to compare it to remotely-sensed data products as well as in situ assessments of forest structure. We ran the FAREAST model at 1,000 randomly selected points within forested areas in the RFE. At each point, the model was calibrated for temperature, precipitation, slope, elevation, and fire

  17. Anticipating the severity of the fire season in Northern Portugal using statistical models based on meteorological indices of fire danger

    NASA Astrophysics Data System (ADS)

    Nunes, Sílvia A.; DaCamara, Carlos C.; Turkman, Kamil F.; Ermida, Sofia L.; Calado, Teresa J.

    2017-04-01

    Like in other regions of Mediterranean Europe, climate and weather are major drivers of fire activity in Portugal. The aim of the present study is to assess the role played by meteorological factors on inter-annual variability of burned area over a region of Portugal characterized by large fire activity. Monthly cumulated values of burned area in August are obtained from the fire database of ICNF, the Portuguese authority for forests. The role of meteorological factors is characterized by means of Daily Severity Rating, DSR, an index of meteorological fire danger, which is derived from meteorological fields as obtained from ECMWF Interim Reanalysis. The study area is characterized by the predominance of forest, with high percentages of maritime pine and eucalyptus, two species with high flammability in summer. The time series of recorded burned area in August during 1980-2011 is highly correlated (correlation coefficient of 0.93) with the one for whole Portugal. First, a normal distribution model is fitted to the 32-year sample of decimal logarithms of monthly burned area. The model is improved by introducing two covariates:(1) the top-down meteorological factor (DSRtd) which consists of daily cumulated values of DSR since April 1 to July 31 and may be viewed as the cumulated stress on vegetation due to meteorological conditions during the pre-fire season; (2) the bottom-up factor (DSRbu) which consists of the square root of the mean of the squared daily deviations (restricted to days with positive departures of DSR from the corresponding long term mean) and may be viewed as the contribution of days characterized by extreme weather conditions favoring the onset and spreading of wildfires. Three different statistical models are then developed: the "climate anomaly" model, using DSRtd as covariate, the "weather anomaly", using DSRbu as covariate, and the "combined" model using both variables as covariates. These models are used to define background fire danger, fire

  18. Incorporating Anthropogenic Influences into Fire Probability Models: Effects of Human Activity and Climate Change on Fire Activity in California

    PubMed Central

    Batllori, Enric; Moritz, Max A.; Waller, Eric K.; Berck, Peter; Flint, Alan L.; Flint, Lorraine E.; Dolfi, Emmalee

    2016-01-01

    The costly interactions between humans and wildfires throughout California demonstrate the need to understand the relationships between them, especially in the face of a changing climate and expanding human communities. Although a number of statistical and process-based wildfire models exist for California, there is enormous uncertainty about the location and number of future fires, with previously published estimates of increases ranging from nine to fifty-three percent by the end of the century. Our goal is to assess the role of climate and anthropogenic influences on the state’s fire regimes from 1975 to 2050. We develop an empirical model that integrates estimates of biophysical indicators relevant to plant communities and anthropogenic influences at each forecast time step. Historically, we find that anthropogenic influences account for up to fifty percent of explanatory power in the model. We also find that the total area burned is likely to increase, with burned area expected to increase by 2.2 and 5.0 percent by 2050 under climatic bookends (PCM and GFDL climate models, respectively). Our two climate models show considerable agreement, but due to potential shifts in rainfall patterns, substantial uncertainty remains for the semiarid inland deserts and coastal areas of the south. Given the strength of human-related variables in some regions, however, it is clear that comprehensive projections of future fire activity should include both anthropogenic and biophysical influences. Previous findings of substantially increased numbers of fires and burned area for California may be tied to omitted variable bias from the exclusion of human influences. The omission of anthropogenic variables in our model would overstate the importance of climatic ones by at least 24%. As such, the failure to include anthropogenic effects in many models likely overstates the response of wildfire to climatic change. PMID:27124597

  19. Incorporating Anthropogenic Influences into Fire Probability Models: Effects of Human Activity and Climate Change on Fire Activity in California.

    PubMed

    Mann, Michael L; Batllori, Enric; Moritz, Max A; Waller, Eric K; Berck, Peter; Flint, Alan L; Flint, Lorraine E; Dolfi, Emmalee

    2016-01-01

    The costly interactions between humans and wildfires throughout California demonstrate the need to understand the relationships between them, especially in the face of a changing climate and expanding human communities. Although a number of statistical and process-based wildfire models exist for California, there is enormous uncertainty about the location and number of future fires, with previously published estimates of increases ranging from nine to fifty-three percent by the end of the century. Our goal is to assess the role of climate and anthropogenic influences on the state's fire regimes from 1975 to 2050. We develop an empirical model that integrates estimates of biophysical indicators relevant to plant communities and anthropogenic influences at each forecast time step. Historically, we find that anthropogenic influences account for up to fifty percent of explanatory power in the model. We also find that the total area burned is likely to increase, with burned area expected to increase by 2.2 and 5.0 percent by 2050 under climatic bookends (PCM and GFDL climate models, respectively). Our two climate models show considerable agreement, but due to potential shifts in rainfall patterns, substantial uncertainty remains for the semiarid inland deserts and coastal areas of the south. Given the strength of human-related variables in some regions, however, it is clear that comprehensive projections of future fire activity should include both anthropogenic and biophysical influences. Previous findings of substantially increased numbers of fires and burned area for California may be tied to omitted variable bias from the exclusion of human influences. The omission of anthropogenic variables in our model would overstate the importance of climatic ones by at least 24%. As such, the failure to include anthropogenic effects in many models likely overstates the response of wildfire to climatic change.

  20. MODEL IDENTIFICATION AND COMPUTER ALGEBRA.

    PubMed

    Bollen, Kenneth A; Bauldry, Shawn

    2010-10-07

    Multiequation models that contain observed or latent variables are common in the social sciences. To determine whether unique parameter values exist for such models, one needs to assess model identification. In practice analysts rely on empirical checks that evaluate the singularity of the information matrix evaluated at sample estimates of parameters. The discrepancy between estimates and population values, the limitations of numerical assessments of ranks, and the difference between local and global identification make this practice less than perfect. In this paper we outline how to use computer algebra systems (CAS) to determine the local and global identification of multiequation models with or without latent variables. We demonstrate a symbolic CAS approach to local identification and develop a CAS approach to obtain explicit algebraic solutions for each of the model parameters. We illustrate the procedures with several examples, including a new proof of the identification of a model for handling missing data using auxiliary variables. We present an identification procedure for Structural Equation Models that makes use of CAS and that is a useful complement to current methods.

  1. Modeling Payload Stowage Impacts on Fire Risks On-Board the International Space Station

    NASA Technical Reports Server (NTRS)

    Anton, Kellie e.; Brown, Patrick F.

    2010-01-01

    The purpose of this presentation is to determine the risks of fire on-board the ISS due to non-standard stowage. ISS stowage is constantly being reexamined for optimality. Non-standard stowage involves stowing items outside of rack drawers, and fire risk is a key concern and is heavily mitigated. A Methodology is needed to account for fire risk due to non-standard stowage to capture the risk. The contents include: 1) Fire Risk Background; 2) General Assumptions; 3) Modeling Techniques; 4) Event Sequence Diagram (ESD); 5) Qualitative Fire Analysis; 6) Sample Qualitative Results for Fire Risk; 7) Qualitative Stowage Analysis; 8) Sample Qualitative Results for Non-Standard Stowage; and 9) Quantitative Analysis Basic Event Data.

  2. Modeling wildland fire propagation with level set methods

    Treesearch

    V. Mallet; D.E Keyes; F.E. Fendell

    2009-01-01

    Level 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...

  3. Modification of VanWagner's canopy fire propagation model

    Treesearch

    James Dickinson; Andrew Robinson; Richy Harrod; Paul Gessler; Alistair Smith

    2007-01-01

    The conditions necessary for the combustion of canopy fuels are not well known but are assumed to be highly influenced by the volume through which the canopy fuels are dispersed, known as canopy bulk density (CBD). Propagating crown fire is defined as a continuous wall of flame from the bottom to the top of the canopy, implying crown fire propagation is actually...

  4. WILDLAND FIRE EMISSION MODELING: INTEGRATING BLUESKY AND SMOKE

    EPA Science Inventory

    This presentation is a summary of an improved method to estimate emissions from wildland fires. An interagency agreement between the US Forest Service and the US EPA has made it possible for these two agencies to collaborate in the study of wildland fires.

  5. WILDLAND FIRE EMISSION MODELING: INTEGRATING BLUESKY AND SMOKE

    EPA Science Inventory

    This presentation is a summary of an improved method to estimate emissions from wildland fires. An interagency agreement between the US Forest Service and the US EPA has made it possible for these two agencies to collaborate in the study of wildland fires.

  6. Wildland fire emissions, carbon, and climate: Modeling fuel consumption

    Treesearch

    Roger D. Ottmar

    2014-01-01

    Fuel consumption specifies the amount of vegetative biomass consumed during wildland fire. It is a two-stage process of pyrolysis and combustion that occurs simultaneously and at different rates depending on the characteristics and condition of the fuel, weather, topography, and in the case of prescribed fire, ignition rate and pattern. Fuel consumption is the basic...

  7. Guidance on spatial wildland fire analysis: models, tools, and techniques

    Treesearch

    Richard D. Stratton

    2006-01-01

    There is an increasing need for spatial wildland fire analysis in support of incident management, fuel treatment planning, wildland-urban assessment, and land management plan development. However, little guidance has been provided to the field in the form of training, support, or research examples. This paper provides guidance to fire managers, planners, specialists,...

  8. Application of a statistical emulator to fire emission modeling

    Treesearch

    Marwan Katurji; Jovanka Nikolic; Shiyuan Zhong; Scott Pratt; Lejiang Yu; Warren E. Heilman

    2015-01-01

    We have demonstrated the use of an advanced Gaussian-Process (GP) emulator to estimate wildland fire emissions over a wide range of fuel and atmospheric conditions. The Fire Emission Production Simulator, or FEPS, is used to produce an initial set of emissions data that correspond to some selected values in the domain of the input fuel and atmospheric parameters for...

  9. Modelling study of NOx removal in oil-fired waste off-gases under electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Zwolińska, Ewa; Sun, Yongxia; Chmielewski, A. G.; Nichipor, H.; Bulka, S.

    2015-08-01

    Computer simulations for high concentration of NOx removal from oil-fired waste off-gases under electron beam irradiation were carried out by using the Computer code "Kinetic" and GEAR method. 293 reactions involving 64 species were used for the modelling calculations. The composition of simulated oil-fired off-gas was the same as the experimental conditions. The calculations were made for following system: (75.78% N2+11.5% CO2+8.62% H2O+4.1% O2), NOx concentration varies from 200 ppm to 1500 ppm. Calculation results qualitatively agree with the experimental results. Furthermore the influence of temperature, SO2 concentration and ammonia addition is discussed.

  10. Fire-BGC: A mechanistic ecological process model for simulating fire succession on coniferous forest landscapes of the northern Rocky Mountains. Forest Service research paper

    SciTech Connect

    Keane, R.E.; Morgan, P.; Running, S.W.

    1996-03-01

    An ecological process model of vegetation dynamics mechanistically simulates long-term stand dynamics on coniferous landscapes of the Northern Rocky Mountains. This model is used to investigate and evaluate cumulative effects of various fire regimes, including prescribed burning and fire exclusion, on the vegetation and fuel complex of a simulation landscape composed of many stands. Detailed documentation of the model FIRE-BGC (a FIRE BioGeoChemical succession model) with complete discussion of all model parameters is followed with results of an application of the FIRE-BGC to a whitebark pine landscape in the Bob Marshall Wilderness Complex. Simulation results of several management scenarios are contrasted to predict the fate of whitebark pine over 200 years. Model testing reveals predictions within 10 to 30 percent of observed values.

  11. Computational models and resource allocation for supercomputers

    NASA Technical Reports Server (NTRS)

    Mauney, Jon; Agrawal, Dharma P.; Harcourt, Edwin A.; Choe, Young K.; Kim, Sukil

    1989-01-01

    There are several different architectures used in supercomputers, with differing computational models. These different models present a variety of resource allocation problems that must be solved. The computational needs of a program must be cast in terms of the computational model supported by the supercomputer, and this must be done in a way that makes effective use of the machine's resources. This is the resource allocation problem. The computational models of available supercomputers and the associated resource allocation techniques are surveyed. It is shown that many problems and solutions appear repeatedly in very different computing environments. Some case studies are presented, showing concrete computational models and the allocation strategies used.

  12. Morphodynamic modelling of the Fire Island Wilderness Breach

    NASA Astrophysics Data System (ADS)

    Van Ormondt, M.

    2016-02-01

    The Wilderness Breach, located within the Otis Pike High Dunes Federal Wilderness Area on Fire Island, NY, was formed during Hurricane Sandy in October 2012 and has remained open, providing a rare opportunity to study the morphologic evolution of a natural breach. Numerical models were used to hindcast the morphodynamic changes since October 2012 in order to gain a better understanding of the processes that govern breach evolution. The model results were compared against repeat bathymetric surveys and aerial imagery. The best match with observations was obtained when using a combination of Delft3D (for calm conditions) and XBeach (for storms) models. The results show a rapid initial growth and westward migration of the breach, apparently caused by a series of storm events in the winter of 2012-2013. Approximately 18 months after formation, breach morphology is governed by seasonal conditions, and the rate of growth has declined substantially. Results provide insights on natural breach evolution that can be used to inform the management of breaches caused by future storm events.

  13. Development of customized fire behavior fuel models for boreal forests of northeastern China.

    PubMed

    Wu, Zhi Wei; He, Hong Shi; Chang, Yu; Liu, Zhi Hua; Chen, Hong Wei

    2011-12-01

    Knowledge of forest fuels and their potential fire behavior across a landscape is essential in fire management. Four customized fire behavior fuel models that differed significantly in fuels characteristics and environmental conditions were identified using hierarchical cluster analysis based on fuels data collected across a boreal forest landscape in northeastern China. Fuel model I represented the dense and heavily branched Pinus pumila shrubland which has significant fine live woody fuels. These forests occur mainly at higher mountain elevations. Fuel model II is applicable to forests dominated by Betula platyphylla and Populus davidiana occurring in native forests on hill slopes or at low mountain elevations. This fuel model was differentiated from other fuel models by higher herbaceous cover and lower fine live woody loading. The primary coniferous forests dominated by Larix gmelini and Pinus sylvestris L. var. mongolica were classified as fuel model III and fuel model IV. Those fuel models differed from one another in average cover and height of understory shrub and herbaceous layers as well as in aspect. The potential fire behavior for each fuel model was simulated with the BehavePlus5.0 fire behavior prediction system. The simulation results indicated that the Pinus pumila shrubland fuels had the most severe fire behavior for the 97th percentile weather condition, and had the least severe fire behavior under 90th percentile weather condition. Fuel model II presented the least severe fire potential across weather conditions. Fuel model IV resulted in greater fire severity than Fuel model III across the two weather scenarios that were examined.

  14. Predicting watershed post-fire sediment yield with the InVEST sediment retention model: Accuracy and uncertainties

    USGS Publications Warehouse

    Sankey, Joel B.; McVay, Jason C.; Kreitler, Jason R.; Hawbaker, Todd J.; Vaillant, Nicole; Lowe, Scott

    2015-01-01

    Increased sedimentation following wildland fire can negatively impact water supply and water quality. Understanding how changing fire frequency, extent, and location will affect watersheds and the ecosystem services they supply to communities is of great societal importance in the western USA and throughout the world. In this work we assess the utility of the InVEST (Integrated Valuation of Ecosystem Services and Tradeoffs) Sediment Retention Model to accurately characterize erosion and sedimentation of burned watersheds. InVEST was developed by the Natural Capital Project at Stanford University (Tallis et al., 2014) and is a suite of GIS-based implementations of common process models, engineered for high-end computing to allow the faster simulation of larger landscapes and incorporation into decision-making. The InVEST Sediment Retention Model is based on common soil erosion models (e.g., USLE – Universal Soil Loss Equation) and determines which areas of the landscape contribute the greatest sediment loads to a hydrological network and conversely evaluate the ecosystem service of sediment retention on a watershed basis. In this study, we evaluate the accuracy and uncertainties for InVEST predictions of increased sedimentation after fire, using measured postfire sediment yields available for many watersheds throughout the western USA from an existing, published large database. We show that the model can be parameterized in a relatively simple fashion to predict post-fire sediment yield with accuracy. Our ultimate goal is to use the model to accurately predict variability in post-fire sediment yield at a watershed scale as a function of future wildfire conditions.

  15. COMPUTATIONAL FLUID DYNAMICS MODELING ANALYSIS OF COMBUSTORS

    SciTech Connect

    Mathur, M.P.; Freeman, Mark; Gera, Dinesh

    2001-11-06

    In the current fiscal year FY01, several CFD simulations were conducted to investigate the effects of moisture in biomass/coal, particle injection locations, and flow parameters on carbon burnout and NO{sub x} inside a 150 MW GEEZER industrial boiler. Various simulations were designed to predict the suitability of biomass cofiring in coal combustors, and to explore the possibility of using biomass as a reburning fuel to reduce NO{sub x}. Some additional CFD simulations were also conducted on CERF combustor to examine the combustion characteristics of pulverized coal in enriched O{sub 2}/CO{sub 2} environments. Most of the CFD models available in the literature treat particles to be point masses with uniform temperature inside the particles. This isothermal condition may not be suitable for larger biomass particles. To this end, a stand alone program was developed from the first principles to account for heat conduction from the surface of the particle to its center. It is envisaged that the recently developed non-isothermal stand alone module will be integrated with the Fluent solver during next fiscal year to accurately predict the carbon burnout from larger biomass particles. Anisotropy in heat transfer in radial and axial will be explored using different conductivities in radial and axial directions. The above models will be validated/tested on various fullscale industrial boilers. The current NO{sub x} modules will be modified to account for local CH, CH{sub 2}, and CH{sub 3} radicals chemistry, currently it is based on global chemistry. It may also be worth exploring the effect of enriched O{sub 2}/CO{sub 2} environment on carbon burnout and NO{sub x} concentration. The research objective of this study is to develop a 3-Dimensional Combustor Model for Biomass Co-firing and reburning applications using the Fluent Computational Fluid Dynamics Code.

  16. Fire emissions simulated by prescribing burned area observations in a global vegetation model

    NASA Astrophysics Data System (ADS)

    Khlystova, Iryna G.; Wilkenskjeld, Stiig; Kloster, Silvia

    2014-05-01

    The emissions of trace gases and aerosols from large vegetation fires into the atmosphere have an important climate impact. In this study we integrate observed burned area into a global vegetation model to derive global fire emissions. A global continuous burned area products provided by GFED (Global Fire Emissions Dataset) were obtained from MODIS (and pre-MODIS) satellites and are available for the time period 1997-2011. We integrate the global burned area product into the global vegetation model JSBACH, a land part of the Earth-System model developed at the Max Planck Institute for Meteorology. JSBACH simulates land biomass in terms of carbon, which can be combined with the satellite burned area information to derive fire carbon emissions. Some assumptions on fire fuel consumptions have to be made during the integration of satellite burned area into the JSBACH. This includes processes such as tree mortality and combustion completeness, i.e. how much of the vegetation biomass gets combusted during a fire. Partially, this information can be also obtained from measurements. In this study we follow closely the approach of GFED, incorporating also GFED supplemental information, to simulate fuel consumption in JSBACH. And we compare simulated by this approach fire carbon emissions with the fire emissions from GFED. Global vegetation models often use prescribed land cover maps. The simulated in the JSBACH vegetation biomass and thus the simulated fire carbon emissions critically depend on the land cover distribution. In our study we derive fire carbon emissions using two different land cover parameterizations, based on two different satellite datasets. We will present the results obtained from simulations using the JSBACH standard MODIS based vegetation distribution and compare them to the results derived using the recently released ESA CCI land cover satellite product to demonstrate the sensitivity of simulated fire carbon emissions to the underlying land cover

  17. Modeling fire spatial non-stationary in Portugal using GWR and GAMLSS

    NASA Astrophysics Data System (ADS)

    Sá, Ana C. L.; Amaral Turkman, Maria A.; Bistinas, Ioannis; Pereira, José M. C.

    2014-05-01

    Portuguese wildfires are responsible for large environmental, ecological and socio-economic impacts and, in the last decade, vegetation fires consumed on average 140.000ha/year. Portugal has a unique fires-atlas of burnt scar perimeters covering the 1975-2009 period, which allows the assessment of the fire most affected areas. It's crucial to understand the influence of the main drivers of forest fires and its spatial distribution in order to set new management strategies to reduce its impacts. Thus, this study aims at evaluating the spatial stationarity of the fire-environment relationship using two statistical approaches: Geographically Weighted Regression (GWR) and Generalized Additive Models for Location, Scale and Shape (GAMLSS). Analysis was performed using a regular 2kmx2km cell size grid, a total of 21293 observations overlaying the mainland of Portugal. Fire incidence was determined as the number of times each grid cell burned in the 35 years period. For the GWR analysis the group of environmental variables selected as predictors are: ignition source (population density (PD)); vegetation (proportion of forest and shrubland (FORSHR)); and weather (total precipitation of the coldest quarter (PCQ). Results showed that the fire-environment relationship is non-stationary, thus the coefficient estimates of all the predictors vary spatially, both in magnitude and sign. The most statistically significant predictor is FORSHR, followed by the PCQ. Despite the relationship between fire incidence and PD is non-stationary, only 9% of the observations are statistically significant at a 95% level of confidence. When compared with the Ordinary Least Squares (OLS) global model, 53% of the R2 statistic is above the 26% global estimated value, meaning a better explanation of the fire incidence variance with the local model approach. Using the same environmental variables, fire incidence was also modeled using GAMLSS to characterize nonstationarities in fire incidence. It is

  18. Project Fire Model: Summary Progress Report, Period November 1, 1958 to April 30, 1960

    Treesearch

    W.L. Fons; H.D. Bruce; W.Y. Pong; S.S. Richards

    1960-01-01

    This report summarizes progress from November 1, 1958, to April 30, 1960, in a study conducted by the Pacific Southwest Forest and Range Experiment Station of the Forest Service in cooperation with the Office of Civil and Defense Mobilization. Called PROJECT FIRE MODEL for convenience, the project sought to develop and study a laboratory-scale fire which would...

  19. 29 CFR Appendix A to Subpart P to... - Model Fire Safety Plan (Non-Mandatory)

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 7 2012-07-01 2012-07-01 false Model Fire Safety Plan (Non-Mandatory) A Appendix A to Subpart P to Part 1915 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH... Fire Protection in Shipyard Employment Pt. 1915, Subpt. P, App. A Appendix A to Subpart P to Part...

  20. 29 CFR Appendix A to Subpart P of... - Model Fire Safety Plan (Non-Mandatory)

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 7 2014-07-01 2014-07-01 false Model Fire Safety Plan (Non-Mandatory) A Appendix A to Subpart P of Part 1915 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH... Fire Protection in Shipyard Employment Pt. 1915, Subpt. P, App. A Appendix A to Subpart P of Part...

  1. First-order fire effects on herbs and Shrubs: present knowledge and process modeling needs

    Treesearch

    Kirsten Stephan; Melanie Miller; Matthew B. Dickinson

    2010-01-01

    Herbaceous plants and shrubs have received little attention in terms of fire effects modeling despite their critical role in ecosystem integrity and resilience after wildfires and prescribed burns. In this paper, we summarize current knowledge of direct effects of fire on herb and shrub (including cacti) vegetative tissues and seed banks, propose key components for...

  2. Estimating emissions from fires in North America for air quality modeling.

    Treesearch

    Christine Wiedinmyer; Brad Quayle; Chris Geron; Angie Belote; Don McKenzie; Xiaoyang Zhang; Susan O' Neill; Kristina Klos. Wynne

    2006-01-01

    Fires contribute substantial emissions of trace gases and particles to the atmosphere. These emissions can impact air quality and even climate. We have developed a modeling framework to estimate the emissions from fires in North and parts of Central America (10-71 ˚N and 55-175 ˚W) by taking advantage of a combination of complementary satellite and...

  3. 29 CFR Appendix A to Subpart P to... - Model Fire Safety Plan (Non-Mandatory)

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Model Fire Safety Plan (Non-Mandatory) A Appendix A to Subpart P to Part 1915 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) OCCUPATIONAL SAFETY AND HEALTH STANDARDS FOR SHIPYARD EMPLOYMENT Fire Protection in Shipyard...

  4. Fuel treatment effects on modeled landscape level fire behavior in the northern Sierra Nevada

    Treesearch

    J.J. Moghaddas; B.M. Collins; K. Menning; E.E.Y. Moghaddas; S.L. Stephens

    2010-01-01

    Across the western United States, decades of fire exclusion combined with past management history have contributed to the current condition of extensive areas of high-density, shade-tolerant coniferous stands that are increasingly prone to high-severity fires. Here, we report the modeled effects of constructed defensible fuel profile zones and group selection...

  5. Using Modeling and Rehearsal to Teach Fire Safety to Children with Autism

    ERIC Educational Resources Information Center

    Garcia, David; Dukes, Charles; Brady, Michael P.; Scott, Jack; Wilson, Cynthia L.

    2016-01-01

    We evaluated the efficacy of an instructional procedure to teach young children with autism to evacuate settings and notify an adult during a fire alarm. A multiple baseline design across children showed that an intervention that included modeling, rehearsal, and praise was effective in teaching fire safety skills. Safety skills generalized to…

  6. Using Modeling and Rehearsal to Teach Fire Safety to Children with Autism

    ERIC Educational Resources Information Center

    Garcia, David; Dukes, Charles; Brady, Michael P.; Scott, Jack; Wilson, Cynthia L.

    2016-01-01

    We evaluated the efficacy of an instructional procedure to teach young children with autism to evacuate settings and notify an adult during a fire alarm. A multiple baseline design across children showed that an intervention that included modeling, rehearsal, and praise was effective in teaching fire safety skills. Safety skills generalized to…

  7. Modeling hazardous fire potential within a completed fuel treatment network in the northern Sierra Nevada

    Treesearch

    Brandon M. Collins; Heather A. Kramer; Kurt Menning; Colin Dillingham; David Saah; Peter A. Stine; Scott L. Stephens

    2013-01-01

    We built on previous work by performing a more in-depth examination of a completed landscape fuel treatment network. Our specific objectives were: (1) model hazardous fire potential with and without the treatment network, (2) project hazardous fire potential over several decades to assess fuel treatment network longevity, and (3) assess fuel treatment effectiveness and...

  8. Advancing investigation and physical modeling of first-order fire effects on soils

    Treesearch

    William J. Massman; John M. Frank; Sacha J. Mooney

    2010-01-01

    Heating soil during intense wildland fires or slash-pile burns can alter the soil irreversibly, resulting in many significant long-term biological, chemical, physical, and hydrological effects. To better understand these long-term effects, it is necessary to improve modeling capability and prediction of the more immediate, or first-order, effects that fire can have on...

  9. Modeling and risk assessment for soil temperatures beneath prescribed forest fires

    Treesearch

    Haiganoush K. Preisler; Sally M. Haase; Stephen S. Sackett

    2000-01-01

    Prescribed fire is a management tool used by wildland resource management organizations in many ecosystems to reduce hazardous fuels and to achieve a host of other objectives. To study the effects of fire in naturally accumulating fuel conditions, the ambient soil temperature is monitored beneath prescribed burns. In this study we developed a stochastic model for...

  10. Computer modeling of piezoresistive gauges

    SciTech Connect

    Nutt, G. L.; Hallquist, J. O.

    1981-08-07

    A computer model of a piezoresistive gauge subject to shock loading is developed. The time-dependent two-dimensional response of the gauge is calculated. The stress and strain components of the gauge are determined assuming elastic-plastic material properties. The model is compared with experiment for four cases. An ytterbium foil gauge in a PPMA medum subjected to a 0.5 Gp plane shock wave, where the gauge is presented to the shock with its flat surface both parallel and perpendicular to the front. A similar comparison is made for a manganin foil subjected to a 2.7 Gp shock. The signals are compared also with a calibration equation derived with the gauge and medium properties accounted for but with the assumption that the gauge is in stress equilibrium with the shocked medium.

  11. Computer modeling of piezoresistive gauges

    SciTech Connect

    Nutt, G.L.; Hallquist, J.O.

    1981-08-07

    A computer model of a piezoresistive gauge subject to shock loading is developed. The time-dependent two-dimensional response of the gauge is calculated. The stress and strain components of the gauge are determined assuming elastic-plastic material properties. The model is compared with experiment for four cases. An ytterbium foil gauge in a PPMA medium subjected to a 5.0 kbar plane shock wave, where the gauge is presented to the shock with its flat surface both parallel and perpendicular to the front. A similar comparison is made for a manganin foil subjected to a 27.5 kbar shock. The signals are compared also with a calibration equation derived with the gauge and medium properties accounted for but with the assumption that the gauge is in stress equilibrium with the shock medium.

  12. Computing Models for FPGA-Based Accelerators

    PubMed Central

    Herbordt, Martin C.; Gu, Yongfeng; VanCourt, Tom; Model, Josh; Sukhwani, Bharat; Chiu, Matt

    2011-01-01

    Field-programmable gate arrays are widely considered as accelerators for compute-intensive applications. A critical phase of FPGA application development is finding and mapping to the appropriate computing model. FPGA computing enables models with highly flexible fine-grained parallelism and associative operations such as broadcast and collective response. Several case studies demonstrate the effectiveness of using these computing models in developing FPGA applications for molecular modeling. PMID:21603152

  13. Evaluation of vegetation fire smoke plume dynamics and aerosol load using UV scanning lidar and fire-atmosphere modelling during the Mediterranean Letia 2010 experiment

    NASA Astrophysics Data System (ADS)

    Leroy-Cancellieri, V.; Augustin, P.; Filippi, J. B.; Mari, C.; Fourmentin, M.; Bosseur, F.; Morandini, F.; Delbarre, H.

    2013-08-01

    Vegetation fires emit large amount of gases and aerosols which are detrimental to human health. Smoke exposure near and downwind of fires depends on the fire propagation, the atmospheric circulations and the burnt vegetation. A better knowledge of the interaction between wildfire and atmosphere is a primary requirement to investigate fire smoke and particle transport. The purpose of this paper is to highlight the usefulness of an UV scanning lidar to characterize the fire smoke plume and consequently validate fire-atmosphere model simulations. An instrumented burn was conducted in a Mediterranean area typical of ones frequently concern by wildfire with low dense shrubs. Using Lidar measurements positioned near the experimental site, fire smoke plume was thoroughly characterized by its optical properties, edge and dynamics. These parameters were obtained by combining methods based on lidar inversion technique, wavelet edge detection and a backscatter barycenter technique. The smoke plume displacement was determined using a digital video camera coupled with the Lidar. The simulation was performed using a meso-scale atmospheric model in a large eddy simulation configuration (Meso-NH) coupled to a fire propagation physical model (ForeFire) taking into account the effect of wind, slope and fuel properties. A passive numerical scalar tracer was injected in the model at fire location to mimic the smoke plume. The simulated fire smoke plume width remained within the edge smoke plume obtained from lidar measurements. The maximum smoke injection derived from lidar backscatter coefficients and the simulated passive tracer was around 200 m. The vertical position of the simulated plume barycenter was systematically below the barycenter derived from the lidar backscatter coefficients due to the oversimplified properties of the passive tracer compared to real aerosols particles. Simulated speed and horizontal location of the plume compared well with the observations derived from

  14. Rapid response tools and datasets for post-fire modeling: linking Earth Observations and process-based hydrological models to support post-fire remediation

    NASA Astrophysics Data System (ADS)

    Miller, M. E.; Billmire, M.; Elliot, W. J.; Endsley, K. A.; Robichaud, P. R.

    2015-04-01

    Preparation is key to utilizing Earth Observations and process-based models to support post-wildfire mitigation. Post-fire flooding and erosion can pose a serious threat to life, property and municipal water supplies. Increased runoff and sediment delivery due to the loss of surface cover and fire-induced changes in soil properties are of great concern. Remediation plans and treatments must be developed and implemented before the first major storms in order to be effective. One of the primary sources of information for making remediation decisions is a soil burn severity map derived from Earth Observation data (typically Landsat) that reflects fire induced changes in vegetation and soil properties. Slope, soils, land cover and climate are also important parameters that need to be considered. Spatially-explicit process-based models can account for these parameters, but they are currently under-utilized relative to simpler, lumped models because they are difficult to set up and require spatially-explicit inputs (digital elevation models, soils, and land cover). Our goal is to make process-based models more accessible by preparing spatial inputs before a fire, so that datasets can be rapidly combined with soil burn severity maps and formatted for model use. We are building an online database (http://geodjango.mtri.org/geowepp /) for the continental United States that will allow users to upload soil burn severity maps. The soil burn severity map is combined with land cover and soil datasets to generate the spatial model inputs needed for hydrological modeling of burn scars. Datasets will be created to support hydrological models, post-fire debris flow models and a dry ravel model. Our overall vision for this project is that advanced GIS surface erosion and mass failure prediction tools will be readily available for post-fire analysis using spatial information from a single online site.

  15. A supply chain network design model for biomass co-firing in coal-fired power plants

    SciTech Connect

    Md. S. Roni; Sandra D. Eksioglu; Erin Searcy; Krishna Jha

    2014-01-01

    We propose a framework for designing the supply chain network for biomass co-firing in coal-fired power plants. This framework is inspired by existing practices with products with similar physical characteristics to biomass. We present a hub-and-spoke supply chain network design model for long-haul delivery of biomass. This model is a mixed integer linear program solved using benders decomposition algorithm. Numerical analysis indicates that 100 million tons of biomass are located within 75 miles from a coal plant and could be delivered at $8.53/dry-ton; 60 million tons of biomass are located beyond 75 miles and could be delivered at $36/dry-ton.

  16. Rapid Response Tools and Datasets for Post-fire Erosion Modeling: An Online Database to Support Post-fire Erosion Modeling

    NASA Astrophysics Data System (ADS)

    Miller, M. E.; Russel, A. M.; Billmire, M.; Endsley, K.; Elliot, W. E.; Robichaud, P. R.; MacDonald, L. H.; Renschler, C. S.

    2013-12-01

    Once the danger posed by an active wildfire has passed, land managers must rapidly assess risks posed by post-fire runoff and erosion due to fire-induced changes in soil properties and the loss of surface cover. Post-fire assessments and proposals to mitigate risks to downstream areas due to flooding, erosion, and sedimentation are typically undertaken by interdisciplinary Burned Area Emergency Response (BAER) teams. One of the first and most important priorities of a BAER team is the development of a burn severity map that reflects the fire-induced changes in both vegetative cover and soils. Currently these maps are known as BARC (Burned Area Reflectance Classification) maps and they are generated from multi-spectral remote sensing data. BAER teams also have access to many erosion modeling tools and datasets, but process-based, spatially explicit models are currently under-utilized relative to simpler, lumped models because they are more difficult to set up and they require the preparation of spatially-explicit data layers such as digital elevation models (DEM), soils, and land cover. We are working to make spatially-explicit modeling easier by preparing large-scale spatial data sets that can be rapidly combined with burn severity maps and then used to quickly run more accurate, process-based models for spatially explicit predictions of post-fire erosion and runoff. A prototype database consisting of 30-m DEM, soil, land cover, and Monitoring Trends in Burn Severity (MTBS) maps for Colorado has been created for use in GeoWEPP (Geo-spatial interface for the Water Erosion Prediction Project) with Disturbed WEPP parameters developed for post-fire conditions. Additional soil data layers have been gathered to support a spatial empirical debris flow model that also utilizes BARC maps. Future plans include developing the dataset to support other models commonly used by BAER teams. The importance of preparing spatial data ahead of time can be illustrated with two

  17. Field models: Their present and future application in fire safety engineering

    NASA Astrophysics Data System (ADS)

    Pedersen, K. S.; Magnussen, B. F.

    1992-12-01

    Different field models for calculating heat load, fire development, and smoke concentrations have been developed for use in fire safety engineering work. The field model versions of KAMELEON are based on a finite difference solution of the basic equations from fluid dynamics together with different mathematical models. The most important of these models are the kappa-epsilon model of turbulence, the eddy dissipation concept of combustion (EDC), the soot model by Magnussen, and the discrete transfer model for radiation by Shah and Lockwood. All the resulting equations are solved three dimensionally and in transient. A version under development is a calculation tool for flame spread on surface linings. The system uses input data from the cone calorimeter. The paper will mainly deal with the description of the numerical code and especially a version called KAMELEON FIRE E-3D, handling enclosed pool fires.

  18. Computer models for economic and silvicultural decisions

    Treesearch

    Rosalie J. Ingram

    1989-01-01

    Computer systems can help simplify decisionmaking to manage forest ecosystems. We now have computer models to help make forest management decisions by predicting changes associated with a particular management action. Models also help you evaluate alternatives. To be effective, the computer models must be reliable and appropriate for your situation.

  19. Pre-fire and post-fire surface fuel and cover measurements collected in the southeastern United States for model evaluation and development - RxCADRE 2008, 2011 and 2012

    Treesearch

    Roger D. Ottmar; Andrew T. Hudak; Susan J. Prichard; Clinton S. Wright; Joseph C. Restaino; Maureen C. Kennedy; Robert E. Vihnanek

    2016-01-01

    A lack of independent, quality-assured data prevents scientists from effectively evaluating predictions and uncertainties in fire models used by land managers. This paper presents a summary of pre-fire and post-fire fuel, fuel moisture and surface cover fraction data that can be used for fire model evaluation and development. The data were collected in the...

  20. Fire radiative forcing for preindustrial, present day and future conditions in an interactive Earth System Model

    NASA Astrophysics Data System (ADS)

    Mezuman, K.; Bauer, S.; Tsigaridis, K.

    2016-12-01

    A climate model with prognostic biomass burning allows us to study the drivers, feedbacks, and interactions of fire in time periods outside of the satellite era. As recent works have shown (e.g. Westerling et al., 2006; Veira et al., 2016) a region's fire activity is sensitive to changing temperatures and the arrival of spring, i.e. a changing climate. Other than regulating the atmospheric carbon monoxide budget, fires release to the atmosphere a suite of reactive gases and aerosol particles that interact with radiation. We set out to study the fire sensitivity of different regions in the world under different climate conditions by further developing the GISS fire model (Pechony and Shindell, 2009, 2010). We implemented a burnt area parameterization, and added a vegetation specific recovery time, which allowed us for the first time to interactively simulate climate and fire activity with GISS-ModelE2.1. Biomass burning occurrence was driven by environmental factors such as vapor pressure deficit and precipitation, as well as natural and anthropogenic ignition. Present day results were evaluated against GFED4 and MODIS data. Our results indicate that humans play an important role in the spatial distribution of fire activity for present day and 2100. Fire related aerosol-radiation interactions and aerosol-cloud interactions are compared per time period and region.