Coupling the Biophysical and Social Dimensions of Wildfire Risk to Improve Wildfire Mitigation Planning.

Science.gov (United States)

Ager, Alan A; Kline, Jeffrey D; Fischer, A Paige

2015-08-01

We describe recent advances in biophysical and social aspects of risk and their potential combined contribution to improve mitigation planning on fire-prone landscapes. The methods and tools provide an improved method for defining the spatial extent of wildfire risk to communities compared to current planning processes. They also propose an expanded role for social science to improve understanding of community-wide risk perceptions and to predict property owners' capacities and willingness to mitigate risk by treating hazardous fuels and reducing the susceptibility of dwellings. In particular, we identify spatial scale mismatches in wildfire mitigation planning and their potential adverse impact on risk mitigation goals. Studies in other fire-prone regions suggest that these scale mismatches are widespread and contribute to continued wildfire dwelling losses. We discuss how risk perceptions and behavior contribute to scale mismatches and how they can be minimized through integrated analyses of landscape wildfire transmission and social factors that describe the potential for collaboration among landowners and land management agencies. These concepts are then used to outline an integrated socioecological planning framework to identify optimal strategies for local community risk mitigation and improve landscape-scale prioritization of fuel management investments by government entities. © 2015 Society for Risk Analysis.

Carbon recovery rates following different wildfire risk mitigation treatments

Science.gov (United States)

M. Hurteau; M. North

2010-01-01

Sequestered forest carbon can provide a climate change mitigation benefit, but in dry temperate forests, wildfire poses a reversal risk to carbon offset projects. Reducing wildfire risk requires a reduction in and redistribution of carbon stocks, the benefit of which is only realized when wildfire occurs. To estimate the time needed to recover carbon removed and...

Before, During, and After a Wildfire

Centers for Disease Control (CDC) Podcasts

More and more people are making their homes in woodland settings – in or near forests, rural areas, or remote mountain sites - areas in which wildfires are more likely to occur. Wildfires often begin unnoticed. They spread quickly, igniting brush, trees, and homes. CDC recommends taking steps before, during, and after local wildfires to reduce the effect they have on your life.

Wildfire risk in the wildland-urban interface: A simulation study in northwestern Wisconsin

Science.gov (United States)

Massada, Avi Bar; Radeloff, Volker C.; Stewart, Susan I.; Hawbaker, Todd J.

2009-01-01

The rapid growth of housing in and near the wildland–urban interface (WUI) increases wildfirerisk to lives and structures. To reduce fire risk, it is necessary to identify WUI housing areas that are more susceptible to wildfire. This is challenging, because wildfire patterns depend on fire behavior and spread, which in turn depend on ignition locations, weather conditions, the spatial arrangement of fuels, and topography. The goal of our study was to assess wildfirerisk to a 60,000 ha WUI area in northwesternWisconsin while accounting for all of these factors. We conducted 6000 simulations with two dynamic fire models: Fire Area Simulator (FARSITE) and Minimum Travel Time (MTT) in order to map the spatial pattern of burn probabilities. Simulations were run under normal and extreme weather conditions to assess the effect of weather on fire spread, burn probability, and risk to structures. The resulting burn probability maps were intersected with maps of structure locations and land cover types. The simulations revealed clear hotspots of wildfire activity and a large range of wildfirerisk to structures in the study area. As expected, the extreme weather conditions yielded higher burn probabilities over the entire landscape, as well as to different land cover classes and individual structures. Moreover, the spatial pattern of risk was significantly different between extreme and normal weather conditions. The results highlight the fact that extreme weather conditions not only produce higher fire risk than normal weather conditions, but also change the fine-scale locations of high risk areas in the landscape, which is of great importance for fire management in WUI areas. In addition, the choice of weather data may limit the potential for comparisons of risk maps for different areas and for extrapolating risk maps to future scenarios where weather conditions are unknown. Our approach to modeling wildfirerisk to structures can aid fire risk reduction management

Wildfire communication and climate risk mitigation

Science.gov (United States)

Robyn S. Wilson; Sarah M. McCaffrey; Eric. Toman

2017-01-01

Throughout the late 19th century and most of the 20th century, risks associated with wildfire were addressed by suppressing fires as quickly as possible. However, by the 1960s, it became clear that fire exclusion policies were having adverse effects on ecological health, as well as contributing to larger and more damaging wildfires over time. Although federal fire...

Provision of a wildfire risk map: informing residents in the wildland urban interface.

Science.gov (United States)

Mozumder, Pallab; Helton, Ryan; Berrens, Robert P

2009-11-01

Wildfires in the wildland urban interface (WUI) are an increasing concern throughout the western United States and elsewhere. WUI communities continue to grow and thus increase the wildfire risk to human lives and property. Information such as a wildfire risk map can inform WUI residents of potential risks and may help to efficiently sort mitigation efforts. This study uses the survey-based contingent valuation (CV) method to examine annual household willingness to pay (WTP) for the provision of a wildfire risk map. Data were collected through a mail survey of the East Mountain WUI area in the State of New Mexico (USA). The integrated empirical approach includes a system of equations that involves joint estimation of WTP values, along with measures of a respondent's risk perception and risk mitigation behavior. The median estimated WTP is around U.S. $12 for the annual wildfire risk map, which covers at least the costs of producing and distributing available risk information. Further, providing a wildfire risk map can help address policy goals emphasizing information gathering and sharing among stakeholders to mitigate the effects of wildfires.

Before, During, and After a Wildfire

Centers for Disease Control (CDC) Podcasts

2007-11-01

More and more people are making their homes in woodland settings – in or near forests, rural areas, or remote mountain sites - areas in which wildfires are more likely to occur. Wildfires often begin unnoticed. They spread quickly, igniting brush, trees, and homes. CDC recommends taking steps before, during, and after local wildfires to reduce the effect they have on your life.  Created: 11/1/2007 by Emergency Communications System.   Date Released: 11/1/2007.

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

Science.gov (United States)

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

Risk preferences in strategic wildfire decision making: a choice experiment with U.S. wildfire managers.

Science.gov (United States)

Wibbenmeyer, Matthew J; Hand, Michael S; Calkin, David E; Venn, Tyron J; Thompson, Matthew P

2013-06-01

Federal policy has embraced risa management as an appropriate paradigm for wildfire management. Economic theory suggests that over repeated wildfire events, potential economic costs and risas of ecological damage are optimally balanced when management decisions are free from biases, risa aversion, and risa seeking. Of primary concern in this article is how managers respond to wildfire risa, including the potential effect of wildfires (on ecological values, structures, and safety) and the likelihood of different fire outcomes. We use responses to a choice experiment questionnaire of U.S. federal wildfire managers to measure attitudes toward several components of wildfire risa and to test whether observed risa attitudes are consistent with the efficient allocation of wildfire suppression resources. Our results indicate that fire managers' decisions are consistent with nonexpected utility theories of decisions under risa. Managers may overallocate firefighting resources when the likelihood or potential magnitude of damage from fires is low, and sensitivity to changes in the probability of fire outcomes depends on whether probabilities are close to one or zero and the magnitude of the potential harm. © 2012 Society for Risk Analysis.

Risk Preferences, Probability Weighting, and Strategy Tradeoffs in Wildfire Management.

Science.gov (United States)

Hand, Michael S; Wibbenmeyer, Matthew J; Calkin, David E; Thompson, Matthew P

2015-10-01

Wildfires present a complex applied risk management environment, but relatively little attention has been paid to behavioral and cognitive responses to risk among public agency wildfire managers. This study investigates responses to risk, including probability weighting and risk aversion, in a wildfire management context using a survey-based experiment administered to federal wildfire managers. Respondents were presented with a multiattribute lottery-choice experiment where each lottery is defined by three outcome attributes: expenditures for fire suppression, damage to private property, and exposure of firefighters to the risk of aviation-related fatalities. Respondents choose one of two strategies, each of which includes "good" (low cost/low damage) and "bad" (high cost/high damage) outcomes that occur with varying probabilities. The choice task also incorporates an information framing experiment to test whether information about fatality risk to firefighters alters managers' responses to risk. Results suggest that managers exhibit risk aversion and nonlinear probability weighting, which can result in choices that do not minimize expected expenditures, property damage, or firefighter exposure. Information framing tends to result in choices that reduce the risk of aviation fatalities, but exacerbates nonlinear probability weighting. © 2015 Society for Risk Analysis.

TA-54 (Area G) Risk Assessment from Extreme Wildfire Scenarios

Energy Technology Data Exchange (ETDEWEB)

Linn, Rodman Ray [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Koo, Eunmo [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Honig, Kristen Ann [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); White, Judith [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Funk, David John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2016-08-10

Los Alamos National Laboratory (LANL) and surrounding areas have been exposed to at least four significant wildfires since 1977 and there have been numerous others within 50 miles of LANL. Based on this history, wildfires are considered a risk to LANL facilities and their contents. While many LANL facilities are at risk to wildfire to some degree, they are found in a wide variety of conditions, thus they have varying sensitivities to wildfires. Additionally, LANL facilities have various functions and different assets, so they have a wide range of values or consequences if compromised. Therefore, determining the risks and precautions that are warranted to mitigate these risks must be done on a case-by-case basis. In an effort to assess possible wildfire risks to sensitive materials stored in a Perma-Con^® in dome TA-54-0375, a conventional fire risk analysis was performed. This conventional risk analysis is documented in Engineering Evaluation Form AP-FIRE-001-FM1, which is dated 9/28/2015 and was titled ‘Wildland Fire Exposure Evaluation for Building TA-54-0375’ (Hall 2015). This analysis acknowledged that there was significant chance of wildfire in the vicinity of TA-54-0375, but the amount of combustible material surrounding the building was deemed low. The wildland fuels that were closest to the building were largely fine fuels and were not expected to have significant duration of heat release. The prevailing winds at this location are from the south and southwest and the nearest significant upwind fuels (tree crowns or unmown grasses) are at least 300 feet away. Based on these factors the conventional wildland fire risk to TA-54-0375 was deemed minimal, “Acceptable As Is, No Action Required.” This risk evaluation was based on a combined assessment of low probability of wildfires arriving at the site from other directions (where higher fuel loadings might be present) as well as the effective setback of fuels in the direction that fire is

The Impact of CO2-Driven Vegetation Changes on Wildfire Risk

Science.gov (United States)

Skinner, C. B.; Poulsen, C. J.

2017-12-01

While wildfires are a key component of natural ecological restoration and succession, they also pose tremendous risks to human life, health, and property. Wildfire frequency is expected to increase in many regions as the radiative effects of elevated CO2 drive warmer surface air temperatures, earlier spring snow melt, and more frequent meteorological drought. However, high CO2 concentrations will also directly impact vegetation growth and physiology, potentially altering wildfire characteristics through changes in fuel amount and surface hydrology. Depending on the biome and time of year, these vegetation-driven responses may mitigate or enhance radiative-driven wildfire changes. In this study, we use a suite of earth system models from the Coupled Model Intercomparison Project 5 with active biogeophysics and biogeochemistry to understand how the vegetation response to high CO2 (CO2 quadrupling) contributes to future changes in wildfire risk across the globe. Across the models, projected CO2 fertilization enhances aboveground biomass (about a 30% leaf area index (LAI) increase averaged across the globe) during the spring and summer months, increasing the availability of wildfire fuel across all biomes. Despite greater LAI, models robustly project widespread reductions in summer season transpiration (about -15% averaged across the globe) in response to reduced stomatal conductance from CO2 physiological forcing. Reduced transpiration warms summer season near surface temperatures and lowers relative humidity across vegetated regions of the mid-to-high latitudes, heightening the risk of wildfire occurrence. However, as transpiration goes down in response to greater plant water use efficiency, a larger fraction of soil water remains in the soil, potentially halting the spread of wildfires in some regions. Given the myriad ways in which the vegetation response to CO2 may alter wildfire risk, and the robustness of the responses across models, an explicit simulation of

Living in a tinderbox: wildfire risk perceptions and mitigating behaviours

Science.gov (United States)

Patricia A. Champ; Geoffrey H. Donovan; Christopher M. Barth

2013-01-01

The loss of homes to wildfires is an important issue in the USA and other countries. Yet many homeowners living in fire-prone areas do not undertake mitigating actions, such as clearing vegetation, to decrease the risk of losing their home. To better understand the complexity of wildfire risk-mitigation decisions and the role of perceived risk, we conducted a survey of...

Catching fire? Social interactions, beliefs, and wildfire risk mitigation behaviors

Science.gov (United States)

Katherine Dickinson; Hannah Brenkert-Smith; Patricia Champ; Nicholas Flores

2015-01-01

Social interactions are widely recognized as a potential influence on risk-related behaviors. We present a mediation model in which social interactions (classified as formal/informal and generic-fire-specific) are associated with beliefs about wildfire risk and mitigation options, which in turn shape wildfire mitigation behaviors. We test this model using survey data...

Wildfire Risk Assessment in a Typical Mediterranean Wildland-Urban Interface of Greece

Science.gov (United States)

Mitsopoulos, Ioannis; Mallinis, Giorgos; Arianoutsou, Margarita

2015-04-01

The purpose of this study was to assess spatial wildfire risk in a typical Mediterranean wildland-urban interface (WUI) in Greece and the potential effect of three different burning condition scenarios on the following four major wildfire risk components: burn probability, conditional flame length, fire size, and source-sink ratio. We applied the Minimum Travel Time fire simulation algorithm using the FlamMap and ArcFuels tools to characterize the potential response of the wildfire risk to a range of different burning scenarios. We created site-specific fuel models of the study area by measuring the field fuel parameters in representative natural fuel complexes, and we determined the spatial extent of the different fuel types and residential structures in the study area using photointerpretation procedures of large scale natural color orthophotographs. The results included simulated spatially explicit fire risk components along with wildfire risk exposure analysis and the expected net value change. Statistical significance differences in simulation outputs between the scenarios were obtained using Tukey's significance test. The results of this study provide valuable information for decision support systems for short-term predictions of wildfire risk potential and inform wildland fire management of typical WUI areas in Greece.

Wildfire risk assessment in a typical Mediterranean wildland-urban interface of Greece.

Science.gov (United States)

Mitsopoulos, Ioannis; Mallinis, Giorgos; Arianoutsou, Margarita

2015-04-01

The purpose of this study was to assess spatial wildfire risk in a typical Mediterranean wildland-urban interface (WUI) in Greece and the potential effect of three different burning condition scenarios on the following four major wildfire risk components: burn probability, conditional flame length, fire size, and source-sink ratio. We applied the Minimum Travel Time fire simulation algorithm using the FlamMap and ArcFuels tools to characterize the potential response of the wildfire risk to a range of different burning scenarios. We created site-specific fuel models of the study area by measuring the field fuel parameters in representative natural fuel complexes, and we determined the spatial extent of the different fuel types and residential structures in the study area using photointerpretation procedures of large scale natural color orthophotographs. The results included simulated spatially explicit fire risk components along with wildfire risk exposure analysis and the expected net value change. Statistical significance differences in simulation outputs between the scenarios were obtained using Tukey's significance test. The results of this study provide valuable information for decision support systems for short-term predictions of wildfire risk potential and inform wildland fire management of typical WUI areas in Greece.

Assessing Wildfire Risk in Cultural Heritage Properties Using High Spatial and Temporal Resolution Satellite Imagery and Spatially Explicit Fire Simulations: The Case of Holy Mount Athos, Greece

Directory of Open Access Journals (Sweden)

Giorgos Mallinis

2016-02-01

Full Text Available Fire management implications and the design of conservation strategies on fire prone landscapes within the UNESCO World Heritage Properties require the application of wildfire risk assessment at landscape level. The objective of this study was to analyze the spatial variation of wildfire risk on Holy Mount Athos in Greece. Mt. Athos includes 20 monasteries and other structures that are threatened by increasing frequency of wildfires. Site-specific fuel models were created by measuring in the field several fuel parameters in representative natural fuel complexes, while the spatial extent of the fuel types was determined using a synergy of high-resolution imagery and high temporal information from medium spatial resolution imagery classified through object-based analysis and a machine learning classifier. The Minimum Travel Time (MTT algorithm, as it is embedded in FlamMap software, was applied in order to evaluate Burn Probability (BP, Conditional Flame Length (CFL, Fire Size (FS, and Source-Sink Ratio (SSR. The results revealed low burn probabilities for the monasteries; however, nine out of the 20 monasteries have high fire potential in terms of fire intensity, which means that if an ignition occurs, an intense fire is expected. The outputs of this study may be used for decision-making for short-term predictions of wildfire risk at an operational level, contributing to fire suppression and management of UNESCO World Heritage Properties.

AEGIS: a wildfire prevention and management information system

Science.gov (United States)

Kalabokidis, Kostas; Ager, Alan; Finney, Mark; Athanasis, Nikos; Palaiologou, Palaiologos; Vasilakos, Christos

2016-03-01

We describe a Web-GIS wildfire prevention and management platform (AEGIS) developed as an integrated and easy-to-use decision support tool to manage wildland fire hazards in Greece (http://aegis.aegean.gr). The AEGIS platform assists with early fire warning, fire planning, fire control and coordination of firefighting forces by providing online access to information that is essential for wildfire management. The system uses a number of spatial and non-spatial data sources to support key system functionalities. Land use/land cover maps were produced by combining field inventory data with high-resolution multispectral satellite images (RapidEye). These data support wildfire simulation tools that allow the users to examine potential fire behavior and hazard with the Minimum Travel Time fire spread algorithm. End-users provide a minimum number of inputs such as fire duration, ignition point and weather information to conduct a fire simulation. AEGIS offers three types of simulations, i.e., single-fire propagation, point-scale calculation of potential fire behavior, and burn probability analysis, similar to the FlamMap fire behavior modeling software. Artificial neural networks (ANNs) were utilized for wildfire ignition risk assessment based on various parameters, training methods, activation functions, pre-processing methods and network structures. The combination of ANNs and expected burned area maps are used to generate integrated output map of fire hazard prediction. The system also incorporates weather information obtained from remote automatic weather stations and weather forecast maps. The system and associated computation algorithms leverage parallel processing techniques (i.e., High Performance Computing and Cloud Computing) that ensure computational power required for real-time application. All AEGIS functionalities are accessible to authorized end-users through a web-based graphical user interface. An innovative smartphone application, AEGIS App, also

Development and application of a geospatial wildfire exposure and risk calculation tool

Science.gov (United States)

Matthew P. Thompson; Jessica R. Haas; Julie W. Gilbertson-Day; Joe H. Scott; Paul Langowski; Elise Bowne; David E. Calkin

2015-01-01

Applying wildfire risk assessment models can inform investments in loss mitigation and landscape restoration, and can be used to monitor spatiotemporal trends in risk. Assessing wildfire risk entails the integration of fire modeling outputs, maps of highly valued resources and assets (HVRAs), characterization of fire effects, and articulation of relative importance...

Pathology of wildfire risk: A characterization of social and ecological dimensions

Science.gov (United States)

A. Paige Fischer; Thomas A Spies; Toddi A Steelman; Cassandra Moseley; Bart R Johnson; John D Bailey; Alan A Ager; Patrick Bourgeron; Susan Charnley; Brandon M Collins; Jeffrey D Kline; Jessica E Leahy; Jeremy S Littell; James DA Millington; Max Nielsen-Pincus; Christine S Olsen; Travis B Paveglio; Christopher I Roos; Michelle M Steen-Adams; Forrest R Stevens; Jelena Vukomanovic; Eric M White; David M. J. S. Bowman

2016-01-01

Despite dramatic increases in suppression spending, the risk of life and property loss associated with wildfire has continued to rise in recent decades. Economic losses from wildfires have doubled in the United States and suppression expenses have tripled between 2002 and 2012 compared to the decade prior. Loss of property to wildfire has outpaced efforts to reduce...

Application of wildfire simulation models for risk analysis

Science.gov (United States)

Ager, A.; Finney, M.

2009-04-01

Wildfire simulation models are being widely used by fire and fuels specialists in the U.S. to support tactical and strategic decisions related to the mitigation of wildfire risk. Much of this application has resulted from the development of a minimum travel time (MTT) fire spread algorithm (M. Finney) that makes it computationally feasible to simulate thousands of fires and generate burn probability and intensity maps over large areas (10,000 - 2,000,000 ha). The MTT algorithm is parallelized for multi-threaded processing and is imbedded in a number of research and applied fire modeling applications. High performance computers (e.g., 32-way 64 bit SMP) are typically used for MTT simulations, although the algorithm is also implemented in the 32 bit desktop FlamMap3 program (www.fire.org). Extensive testing has shown that this algorithm can replicate large fire boundaries in the heterogeneous landscapes that typify much of the wildlands in the western U.S. In this paper, we describe the application of the MTT algorithm to understand spatial patterns of burn probability (BP), and to analyze wildfire risk to key human and ecological values. The work is focused on a federally-managed 2,000,000 ha landscape in the central interior region of Oregon State, USA. The fire-prone study area encompasses a wide array of topography and fuel types and a number of highly valued resources that are susceptible to fire. We quantitatively defined risk as the product of the probability of a fire and the resulting consequence. Burn probabilities at specific intensity classes were estimated for each 100 x 100 m pixel by simulating 100,000 wildfires under burn conditions that replicated recent severe wildfire events that occurred under conditions where fire suppression was generally ineffective (97th percentile, August weather). We repeated the simulation under milder weather (70th percentile, August weather) to replicate a "wildland fire use scenario" where suppression is minimized to

Integrated national-scale assessment of wildfire risk to human and ecological values

Science.gov (United States)

Matthew P. Thompson; David E. Calkin; Mark A. Finney; Alan A. Ager; Julie W. Gilbertson-Day

2011-01-01

The spatial, temporal, and social dimensions of wildfire risk are challenging U.S. federal land management agencies to meet societal needs while maintaining the health of the lands they manage. In this paper we present a quantitative, geospatial wildfire risk assessment tool, developed in response to demands for improved risk-based decision frameworks. The methodology...

Modeling Wildfire Hazard in the Western Hindu Kush-Himalayas

Science.gov (United States)

Bylow, D.

2012-12-01

Wildfire regimes are a leading driver of global environmental change affecting a diverse array of global ecosystems. Particulates and aerosols produced by wildfires are a primary source of air pollution making the early detection and monitoring of wildfires crucial. The objectives of this study were to model regional wildfire potential and identify environmental, topological, and sociological factors that contribute to the ignition of wildfire events in the Western Hindu Kush-Himalayas of South Asia. The environmental, topological, and sociological factors were used to model regional wildfire potential through multi-criteria evaluation using a method of weighted linear combination. Moderate Resolution Imaging Spectroradiometer (MODIS) and geographic information systems (GIS) data were integrated to analyze regional wildfires and construct the model. Model validation was performed using a holdout cross validation method. The study produced a significant model of wildfire potential in the Western Hindu Kush-Himalayas.; Western Hindu Kush-Himalayas ; Western Hindu Kush-Himalayas Wildfire Potential

Earth, wind, and fire: Wildfire risk perceptions in a hurricane-prone environment

Science.gov (United States)

Soren M. Newman; Matthew S. Carroll; Pamela J. Jakes; Daniel R. Williams; Lorie L. Higgins

2014-01-01

Wildfire is one of several potential disturbances that could have extraordinary impacts on individuals and communities in fire-prone areas. In this article we describe disturbance risk perceptions from interviews with residents in three Florida communities that face significant wildfire and hurricane risk. Although they live in areas characterized by emergency managers...

Assessing Landscape Scale Wildfire Exposure for Highly Valued Resources in a Mediterranean Area

Science.gov (United States)

Alcasena, Fermín J.; Salis, Michele; Ager, Alan A.; Arca, Bachisio; Molina, Domingo; Spano, Donatella

2015-05-01

We used a fire simulation modeling approach to assess landscape scale wildfire exposure for highly valued resources and assets (HVR) on a fire-prone area of 680 km2 located in central Sardinia, Italy. The study area was affected by several wildfires in the last half century: some large and intense fire events threatened wildland urban interfaces as well as other socioeconomic and cultural values. Historical wildfire and weather data were used to inform wildfire simulations, which were based on the minimum travel time algorithm as implemented in FlamMap. We simulated 90,000 fires that replicated recent large fire events in the area spreading under severe weather conditions to generate detailed maps of wildfire likelihood and intensity. Then, we linked fire modeling outputs to a geospatial risk assessment framework focusing on buffer areas around HVR. The results highlighted a large variation in burn probability and fire intensity in the vicinity of HVRs, and allowed us to identify the areas most exposed to wildfires and thus to a higher potential damage. Fire intensity in the HVR buffers was mainly related to fuel types, while wind direction, topographic features, and historically based ignition pattern were the key factors affecting fire likelihood. The methodology presented in this work can have numerous applications, in the study area and elsewhere, particularly to address and inform fire risk management, landscape planning and people safety on the vicinity of HVRs.

Assessing landscape scale wildfire exposure for highly valued resources in a Mediterranean area.

Science.gov (United States)

Alcasena, Fermín J; Salis, Michele; Ager, Alan A; Arca, Bachisio; Molina, Domingo; Spano, Donatella

2015-05-01

We used a fire simulation modeling approach to assess landscape scale wildfire exposure for highly valued resources and assets (HVR) on a fire-prone area of 680 km(2) located in central Sardinia, Italy. The study area was affected by several wildfires in the last half century: some large and intense fire events threatened wildland urban interfaces as well as other socioeconomic and cultural values. Historical wildfire and weather data were used to inform wildfire simulations, which were based on the minimum travel time algorithm as implemented in FlamMap. We simulated 90,000 fires that replicated recent large fire events in the area spreading under severe weather conditions to generate detailed maps of wildfire likelihood and intensity. Then, we linked fire modeling outputs to a geospatial risk assessment framework focusing on buffer areas around HVR. The results highlighted a large variation in burn probability and fire intensity in the vicinity of HVRs, and allowed us to identify the areas most exposed to wildfires and thus to a higher potential damage. Fire intensity in the HVR buffers was mainly related to fuel types, while wind direction, topographic features, and historically based ignition pattern were the key factors affecting fire likelihood. The methodology presented in this work can have numerous applications, in the study area and elsewhere, particularly to address and inform fire risk management, landscape planning and people safety on the vicinity of HVRs.

Coupling the biophysical and social dimensions of wildfire risk to improve wildfire mitigation planning

Science.gov (United States)

Alan A. Ager; Jeffrey D. Kline; A. Paige Fisher

2015-01-01

We describe recent advances in biophysical and social aspects of risk and their potential combined contribution to improve mitigation planning on fire-prone landscapes. The methods and tools provide an improved method for defining the spatial extent of wildfire risk to communities compared to current planning processes. They also propose an expanded role for social...

Investigation of the decline in reported smoking-caused wildfires in the USA from 2000 to 2011

Science.gov (United States)

David T. Butry; Jeffrey P. Prestemon; Douglas S. Thomas

2014-01-01

The number of smoking-caused wildfires has been falling nationwide. In national forests in 2011, smoking-caused wildfires represented only 10% of their 1980 level. No other cause of wildfire has experienced this level of decline. For 12 states, we evaluate the rate of smoking-caused wildfires and find it is a function of weather, other ignitions, the number of adult...

From Data to Knowledge — Faster: GOES Early Fire Detection System to Inform Operational Wildfire Response and Management

Science.gov (United States)

Koltunov, A.; Quayle, B.; Prins, E. M.; Ambrosia, V. G.; Ustin, S.

2014-12-01

Fire managers at various levels require near-real-time, low-cost, systematic, and reliable early detection capabilities with minimal latency to effectively respond to wildfire ignitions and minimize the risk of catastrophic development. The GOES satellite images collected for vast territories at high temporal frequencies provide a consistent and reliable source for operational active fire mapping realized by the WF-ABBA algorithm. However, their potential to provide early warning or rapid confirmation of initial fire ignition reports from conventional sources remains underutilized, partly because the operational wildfire detection has been successfully optimized for users and applications for which timeliness of initial detection is a low priority, contrasting to the needs of first responders. We present our progress in developing the GOES Early Fire Detection (GOES-EFD) system, a collaborative effort led by University of California-Davis and USDA Forest Service. The GOES-EFD specifically focuses on first detection timeliness for wildfire incidents. It is automatically trained for a monitored scene and capitalizes on multiyear cross-disciplinary algorithm research. Initial retrospective tests in Western US demonstrate significantly earlier identification detection of new ignitions than existing operational capabilities and a further improvement prospect. The GOES-EFD-β prototype will be initially deployed for the Western US region to process imagery from GOES-NOP and the rapid and 4 times higher spatial resolution imagery from GOES-R — the upcoming next generation of GOES satellites. These and other enhanced capabilities of GOES-R are expected to significantly improve the timeliness of fire ignition information from GOES-EFD.

A conceptual framework for coupling the biophysical and social dimensions of wildfire to improve fireshed planning and risk mitigation

Science.gov (United States)

Jeff Kline; Alan A. Ager; Paige Fischer

2015-01-01

The need for improved methods for managing wildfire risk is becoming apparent as uncharacteristically large wildfires in the western US and elsewhere exceed government capacities for their control and suppression. We propose a coupled biophysical-social framework to managing wildfire risk that relies on wildfire simulation to identify spatial patterns of wildfire risk...

Social amplification of wildfire risk: The role of social interactions and information sources

Science.gov (United States)

Hannah Brenkert-Smith; Katherine L. Dickinson; Patricia A. Champ; Nicholas Flores

2013-01-01

Wildfire is a persistent and growing threat across much of the western United States. Understanding how people living in fire-prone areas perceive this threat is essential to the design of effective risk management policies. Drawing on the social amplification of risk framework, we develop a conceptual model of wildfire risk perceptions that incorporates the social...

Regional variation in fire weather controls the reported occurrence of Scottish wildfires

Directory of Open Access Journals (Sweden)

G. Matt Davies

2016-11-01

Full Text Available Fire is widely used as a traditional habitat management tool in Scotland, but wildfires pose a significant and growing threat. The financial costs of fighting wildfires are significant and severe wildfires can have substantial environmental impacts. Due to the intermittent occurrence of severe fire seasons, Scotland, and the UK as a whole, remain somewhat unprepared. Scotland currently lacks any form of Fire Danger Rating system that could inform managers and the Fire and Rescue Services (FRS of periods when there is a risk of increased of fire activity. We aimed evaluate the potential to use outputs from the Canadian Fire Weather Index system (FWI system to forecast periods of increased fire risk and the potential for ignitions to turn into large wildfires. We collated four and a half years of wildfire data from the Scottish FRS and examined patterns in wildfire occurrence within different regions, seasons, between urban and rural locations and according to FWI system outputs. We used a variety of techniques, including Mahalanobis distances, percentile analysis and Thiel-Sen regression, to scope the best performing FWI system codes and indices. Logistic regression showed significant differences in fire activity between regions, seasons and between urban and rural locations. The Fine Fuel Moisture Code and the Initial Spread Index did a tolerable job of modelling the probability of fire occurrence but further research on fuel moisture dynamics may provide substantial improvements. Overall our results suggest it would be prudent to ready resources and avoid managed burning when FFMC > 75 and/or ISI > 2.

Regional variation in fire weather controls the reported occurrence of Scottish wildfires.

Science.gov (United States)

Davies, G Matt; Legg, Colin J

2016-01-01

Fire is widely used as a traditional habitat management tool in Scotland, but wildfires pose a significant and growing threat. The financial costs of fighting wildfires are significant and severe wildfires can have substantial environmental impacts. Due to the intermittent occurrence of severe fire seasons, Scotland, and the UK as a whole, remain somewhat unprepared. Scotland currently lacks any form of Fire Danger Rating system that could inform managers and the Fire and Rescue Services (FRS) of periods when there is a risk of increased of fire activity. We aimed evaluate the potential to use outputs from the Canadian Fire Weather Index system (FWI system) to forecast periods of increased fire risk and the potential for ignitions to turn into large wildfires. We collated four and a half years of wildfire data from the Scottish FRS and examined patterns in wildfire occurrence within different regions, seasons, between urban and rural locations and according to FWI system outputs. We used a variety of techniques, including Mahalanobis distances, percentile analysis and Thiel-Sen regression, to scope the best performing FWI system codes and indices. Logistic regression showed significant differences in fire activity between regions, seasons and between urban and rural locations. The Fine Fuel Moisture Code and the Initial Spread Index did a tolerable job of modelling the probability of fire occurrence but further research on fuel moisture dynamics may provide substantial improvements. Overall our results suggest it would be prudent to ready resources and avoid managed burning when FFMC > 75 and/or ISI > 2.

Incentives for Ex Ante wildfire risk mitigation in the wildland-urban interface: The relationship between contingent wildfire insurance and fuel management subsidies

OpenAIRE

Lankoande, Mariam D.; Yoder, Jonathan K.; Wandschneider, Philip R.

2006-01-01

Contingent wildfire insurance and fuel management cost-sharing programs are becoming more prevalent in western states. This paper develops a model to examine the incentive effects of these two mechanisms for private investment in wildfire risk mitigation. The model shows that contingent insurance contracts strengthen incentives for risk mitigation relative to pooled contracts and subsidies induce more risk mitigation effort by reducing margin private costs of mitigation. With pooled insurance...

Assessing influences on social vulnerability to wildfire using surveys, spatial data and wildfire simulations.

Science.gov (United States)

Paveglio, Travis B; Edgeley, Catrin M; Stasiewicz, Amanda M

2018-05-01

A growing body of research focuses on identifying patterns among human populations most at risk from hazards such as wildfire and the factors that help explain performance of mitigations that can help reduce that risk. Emerging policy surrounding wildfire management emphasizes the need to better understand such social vulnerability-or human populations' potential exposure to and sensitivity from wildfire-related impacts, including their ability to reduce negative impacts from the hazard. Studies of social vulnerability to wildfire often pair secondary demographic data with a variety of vegetation and wildfire simulation models to map potential risk. However, many of the assumptions made by those researchers about the demographic, spatial or perceptual factors that influence social vulnerability to wildfire have not been fully evaluated or tested against objective measures of potential wildfire risk. The research presented here utilizes self-reported surveys, GIS data, and wildfire simulations to test the relationships between select perceptual, demographic, and property characteristics of property owners against empirically simulated metrics for potential wildfire related damages or exposure. We also evaluate how those characteristics relate to property owners' performance of mitigations or support for fire management. Our results suggest that parcel characteristics provide the most significant explanation of variability in wildfire exposure, sensitivity and overall wildfire risk, while the positive relationship between income or property values and components of social vulnerability stands in contrast to typical assumptions from existing literature. Respondents' views about agency or government management helped explain a significant amount of variance in wildfire sensitivity, while the importance of wildfire risk in selecting a residence was an important influence on mitigation action. We use these and other results from our effort to discuss updated

Assessing increasing susceptibility to wildfire at the wildland-urban fringe in the western United States

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Kinoshita, A. M.; Hogue, T. S.

2013-05-01

Much of the western U.S. is increasingly susceptible to wildfire activity due to drier conditions, elevated fuel loads, and expanding urbanization. As population increases, development pushes the urban boundary further into wildlands, creating more potential for human interaction at the wildland-urban interface (WUI), primarily from human ignitions and fire suppression policies. The immediate impacts of wildfires include vulnerability to debris flows, flooding, and impaired water quality. Fires also alter longer-term hydrological and ecosystem behavior. The current study utilizes geospatial datasets to investigate historical wildfire size and frequency relative to the WUI for a range of cities across western North America. California, the most populous state in the U.S., has an extensive fire history. The decennial population and acres burned for four major counties (Los Angeles, San Bernardino, San Diego, and Shasta) in California show that increasing wildfire size and frequency follow urbanization trends, with high correlation between the last decade of burned area, urban-fringe proximity, and increasing population. Ultimately, results will provide information on urban fringe communities that are most vulnerable to the risks associated with wildfire and post-fire impacts. In light of evolving land use policies (i.e. forest management and treatment, development at the urban-fringe) and climate change, it is critical to advance our knowledge of the implications that these conditions pose to urban centers, communicate risks to the public, and ultimately provide guidance for wildfire management.

Is timber insurable? A study of wildfire Risks in the U.S. forest sector using spatio-temporal models.

Science.gov (United States)

Xuan Chen; Barry K. Goodwin; Jeffrey P. Prestemon

2014-01-01

In the U.S. forest products industry, wildfire is one of the leading causes of damage and economic losses. While individual wildfire behavior is well studied, new literature is emerging on broad-scale (e.g., county-level) wildfire risks. Our paper studies wildfire risks using crucial informational vari­ ables across both spatio units and time periods....

Extreme Wildfire Spread and Behaviour: Case Studies from North Sardinia, Italy

Science.gov (United States)

Salis, M.; Arca, B.; Ager, A.; Fois, C.; Bacciu, V.; Duce, P.; Spano, D.

2012-04-01

Worldwide, fire seasons are usually characterized by the occurrence of one or more days with extreme environmental conditions, such as heat waves associated with strong winds. On these days, fires can quickly get out of hand originating large and severe wildfires. In these cases, containment and extinguishment phases are critical, considering that the imperative goal is to keep fire crews, people and animals safe. In this work we will present a set of large and severe wildfires occurred with extreme environmental conditions in the northern area of Sardinia. The most recent wildfire we will describe was ignited on July 13, 2011 in the Oschiri municipality (40°43' N; 9°06' E), and burned about 2,500 ha of wooded and herbaceous pastures and oakwoods in few hours. The second wildfire we will present was ignited on July 23, 2009 in the Bonorva municipality (40°25' N; 8° 46' E), and was responsible for the death of two people and several damages to houses, animals and farms. This wildfire lasted on July 25, and burned about 10,000 ha of wooded and herbaceous pastures; the most of the area was burned during the first day. The last wildfire we will describe was ignited on July 23, 2007 in the Oniferi municipality (40°16' N; 9° 16' E) and burned about 9,000 ha of wooded and herbaceous pastures and oakwoods; about 8,000 ha were burned after 11 hours of propagation. All these wildfires were ignited in days characterized by very hot temperatures associated to the effect of air masses moving from inland North Africa to the Mediterranean Basin, and strong winds from west-south west. This is one of the typical weather pattern associated with large and severe wildfires in North Sardinia, and is well documented in the last years. Weather conditions, fuels and topography factors related to each case study will be accurately analyzed. Moreover, a detailed overview of observed fire spread and behavior and post-fire vegetation recovery will be presented. The fire spread and

The Spotting Distribution of Wildfires

Directory of Open Access Journals (Sweden)

Jonathan Martin

2016-06-01

Full Text Available In wildfire science, spotting refers to non-local creation of new fires, due to downwind ignition of brands launched from a primary fire. Spotting is often mentioned as being one of the most difficult problems for wildfire management, because of its unpredictable nature. Since spotting is a stochastic process, it makes sense to talk about a probability distribution for spotting, which we call the spotting distribution. Given a location ahead of the fire front, we would like to know how likely is it to observe a spot fire at that location in the next few minutes. The aim of this paper is to introduce a detailed procedure to find the spotting distribution. Most prior modelling has focused on the maximum spotting distance, or on physical subprocesses. We will use mathematical modelling, which is based on detailed physical processes, to derive a spotting distribution. We discuss the use and measurement of this spotting distribution in fire spread, fire management and fire breaching. The appendix of this paper contains a comprehensive review of the relevant underlying physical sub-processes of fire plumes, launching fire brands, wind transport, falling and terminal velocity, combustion during transport, and ignition upon landing.

Explore inhabitants’ perceptions of wildfire and mitigation behaviours in the Cerrado biome, a fire-prone area of Brazil

Directory of Open Access Journals (Sweden)

Giovanni Santopuoli

2017-05-01

Full Text Available Fire represents an important natural feature of Brazilian landscape, especially in the Cerrado biome. The Cerrado is the economic livelihood of thousands of people from rural areas in Brazil. It is one of the most important hotspot of biodiversity in the world but also it is a fire-prone area thanks to the high flammability index of the vegetation. Residents and native people of this environment use fire very frequently. The majority of wildfires are caused by humans, though there are some aggravating natural factors affecting the risk, intensity and severity of wildfires. Since residents are continuously involved in fire suppression activities, understanding their perceptions is important for the decision makers who must assess the local capacity to preserve natural resources. This study explores perceptions about wildfire risk and fire mitigation behaviors within three municipalities of the state of Tocantins (Brazil. The study demonstrates that survey participants perceived wildfire risk as rather high, although the perceptions were complex and conflicting among interviewees. A wide range of confused perceptions about fire ignition and heterogeneous point of view have carried out form the survey. However, the residence of interviewees and their educational attainment result the variables that significantly (p-value <0.05 affect the inhabitants’ perceptions.

Wildfire risk and home purchase decisions.

Science.gov (United States)

Patricia Champ; Geoffrey Donovan; Christopher Barth

2008-01-01

In the last 20 years, wildfire damages and the costs of wildfire suppression have risen dramatically. This trend has been attributed to three main factors: climate change, increased fuel loads from a century of wildfire suppression, and increased housing development in fire-prone areas., There is little that fire managers can do about climate change, and current fuel...

Simulating wildfire spread behavior between two NASA Active Fire data timeframes

Science.gov (United States)

Adhikari, B.; Hodza, P.; Xu, C.; Minckley, T. A.

2017-12-01

Although NASA's Active Fire dataset is considered valuable in mapping the spatial distribution and extent of wildfires across the world, the data is only available at approximately 12-hour time intervals, creating uncertainties and risks associated with fire spread and behavior between the two Visible Infrared Imaging Radiometer Satellite (VIIRS) data collection timeframes. Our study seeks to close the information gap for the United States by using the latest Active Fire data collected for instance around 0130 hours as an ignition source and critical inputs to a wildfire model by uniquely incorporating forecasted and real-time weather conditions for predicting fire perimeter at the next 12 hour reporting time (i.e. around 1330 hours). The model ingests highly dynamic variables such as fuel moisture, temperature, relative humidity, wind among others, and prompts a Monte Carlo simulation exercise that uses a varying range of possible values for evaluating all possible wildfire behaviors. The Monte Carlo simulation implemented in this model provides a measure of the relative wildfire risk levels at various locations based on the number of times those sites are intersected by simulated fire perimeters. Model calibration is achieved using data at next reporting time (i.e. after 12 hours) to enhance the predictive quality at further time steps. While initial results indicate that the calibrated model can predict the overall geometry and direction of wildland fire spread, the model seems to over-predict the sizes of most fire perimeters possibly due to unaccounted fire suppression activities. Nonetheless, the results of this study show great promise in aiding wildland fire tracking, fighting and risk management.

75 FR 80799 - Preparation of the PEIS for Modernization of Training Infrastructure at Pōhakuloa Training Area, HI

Science.gov (United States)

2010-12-23

... risk of igniting wildfires or may result in a loss of cultural resources. The Army will identify... resources, cultural resources, public services and utilities, wildfires, and hazardous materials and waste. There could be significant impacts to cultural resources, air quality, and risk from igniting wildfires...

A global assessment of wildfire risks to human and environmental water security

Science.gov (United States)

Robinne, François-Nicolas; Parisien, Marc-André; Flannigan, Mike; Miller, Carol; Bladon, Kevin D.

2017-04-01

Extreme wildfire events extensively affect hydrosystem stability and generate an important threat to the reliability of the water supply for human and natural communities. While actively studied at the watershed scale, the development of a global vision of wildfire risk to water security has only been undertaken recently, pointing at potential water security concerns in an era of global changes. In order to address this concern, we propose a global-scale analysis of the wildfire risk to surface water supplies based on the Driving forces-Pressures-States-Impacts-Responses (DPSIR) framework. This framework relies on the cause-and-effect relationships existing between the five categories of the DPSIR chain. Based on the literature, we gathered an extensive set of spatial indicators relevant to fire-induced hydrological hazards and water consumption patterns by human and natural communities. Each indicator was assigned a DPSIR category. Then, we collapsed the information in each category using a principal component analysis in order to extract the most relevant pixel-based information provided by each spatial indicator. Finally, we compiled our five categories using an additive indexation process to produce a spatially-explicit index of the wildfire-water risk (WWR). For comparison purposes, we aggregated index scores by global hydrological regions, or hydrobelts, for analysis. Overall, our results show a distinct pattern of medium-to-high risk levels in areas where sizeable wildfire activity, water resources, and water consumption are concomitant, which mainly encompasses temperate and sub-tropical zones. A closer look at hydrobelts reveals differences in the factors driving the risk, with fire activity being the primary factor of risk in the circumboreal forest, and freshwater resource density being prevalent in tropical areas. We also identified major urban areas across the world whose source waters should be protected from extreme fire events, particularly when

Cost shared wildfire risk mitigation in Log Hill Mesa, Colorado: Survey evidence on participation and willingness to pay

Science.gov (United States)

James R. Meldrum; Patricia A. Champ; Travis Warziniack; Hannah Brenkert-Smith; Christopher M. Barth; Lilia C. Falk

2014-01-01

Wildland-urban interface (WUI) homeowners who do not mitigate the wildfire risk on their properties impose a negative externality on society. To reduce the social costs of wildfire and incentivise homeowners to take action, cost sharing programs seek to reduce the barriers that impede wildfire risk mitigation. Using survey data from a WUI community in western Colorado...

The role of risk perceptions in the risk mitigation process: The case of wildfire in high risk communities

Science.gov (United States)

Wade E. Martin; Ingrid M. Martin; Brian Kent

2009-01-01

An important policy question receiving considerable attention concerns the risk perception-risk mitigation process that guides how individuals choose to address natural hazard risks. This question is considered in the context of wildfire. We analyze the factors that influence risk reduction behaviors by homeowners living in the wildland-urban interface. The factors...

Piloted ignition of live forest fuels

Science.gov (United States)

S. McAllister; I. Grenfell; A. Hadlow; W. M. Jolly; M. Finney; J. Cohen

2012-01-01

The most unpredictable and uncontrollable wildfires are those that burn in the crowns of live vegetation. The fuels that feed these crown fires are mostly live, green foliage. Unfortunately, little is known about how live fuels combust. To understand how live fuels burn, piloted ignition experiments were performed with lodgepole pine and Douglas-fir. The thermal...

Race and wildfire risk perceptions among rural forestland owners in north-central Florida

Science.gov (United States)

Miriam Wyman; Sparkle Malone; Taylor Stein; Cassandra Johnson

2012-01-01

The southern United States is susceptible to wildfire, from its climate, growing seasons, lightning frequency, and decades of fire suppression. With much known about wildfire’s biophysical risks, less is understood about sociodemographic obstacles, including race, income, and education. Blacks in the rural southeastern United States are typically among the most...

Probabilistic risk models for multiple disturbances: an example of forest insects and wildfires

Science.gov (United States)

Haiganoush K. Preisler; Alan A. Ager; Jane L. Hayes

2010-01-01

Building probabilistic risk models for highly random forest disturbances like wildfire and forest insect outbreaks is a challenging. Modeling the interactions among natural disturbances is even more difficult. In the case of wildfire and forest insects, we looked at the probability of a large fire given an insect outbreak and also the incidence of insect outbreaks...

Estimation of wildfire size and risk changes due to fuels treatments

Science.gov (United States)

Cochrane, M.A.; Moran, C.J.; Wimberly, M.C.; Baer, A.D.; Finney, M.A.; Beckendorf, K.L.; Eidenshink, J.; Zhu, Z.

2012-01-01

Human land use practices, altered climates, and shifting forest and fire management policies have increased the frequency of large wildfires several-fold. Mitigation of potential fire behaviour and fire severity have increasingly been attempted through pre-fire alteration of wildland fuels using mechanical treatments and prescribed fires. Despite annual treatment of more than a million hectares of land, quantitative assessments of the effectiveness of existing fuel treatments at reducing the size of actual wildfires or how they might alter the risk of burning across landscapes are currently lacking. Here, we present a method for estimating spatial probabilities of burning as a function of extant fuels treatments for any wildland fire-affected landscape. We examined the landscape effects of more than 72 000 ha of wildland fuel treatments involved in 14 large wildfires that burned 314 000 ha of forests in nine US states between 2002 and 2010. Fuels treatments altered the probability of fire occurrence both positively and negatively across landscapes, effectively redistributing fire risk by changing surface fire spread rates and reducing the likelihood of crowning behaviour. Trade offs are created between formation of large areas with low probabilities of increased burning and smaller, well-defined regions with reduced fire risk.

Advancing effects analysis for integrated, large-scale wildfire risk assessment

Science.gov (United States)

Matthew P. Thompson; David E. Calkin; Julie W. Gilbertson-Day; Alan A. Ager

2011-01-01

In this article, we describe the design and development of a quantitative, geospatial risk assessment tool intended to facilitate monitoring trends in wildfire risk over time and to provide information useful in prioritizing fuels treatments and mitigation measures. The research effort is designed to develop, from a strategic view, a first approximation of how both...

Assessing Watershed-Wildfire Risks on National Forest System Lands in the Rocky Mountain Region of the United States

Directory of Open Access Journals (Sweden)

Jessica R. Haas

2013-07-01

Full Text Available Wildfires can cause significant negative impacts to water quality with resultant consequences for the environment and human health and safety, as well as incurring substantial rehabilitation and water treatment costs. In this paper we will illustrate how state-of-the-art wildfire simulation modeling and geospatial risk assessment methods can be brought to bear to identify and prioritize at-risk watersheds for risk mitigation treatments, in both pre-fire and post-fire planning contexts. Risk assessment results can be particularly useful for prioritizing management of hazardous fuels to lessen the severity and likely impacts of future wildfires, where budgetary and other constraints limit the amount of area that can be treated. Specifically we generate spatially resolved estimates of wildfire likelihood and intensity, and couple that information with spatial data on watershed location and watershed erosion potential to quantify watershed exposure and risk. For a case study location we focus on National Forest System lands in the Rocky Mountain Region of the United States. The Region houses numerous watersheds that are critically important to drinking water supplies and that have been impacted or threatened by large wildfires in recent years. Assessment results are the culmination of a broader multi-year science-management partnership intended to have direct bearing on wildfire management decision processes in the Region. Our results suggest substantial variation in the exposure of and likely effects to highly valued watersheds throughout the Region, which carry significant implications for prioritization. In particular we identified the San Juan National Forest as having the highest concentration of at-risk highly valued watersheds, as well as the greatest amount of risk that can be mitigated via hazardous fuel reduction treatments. To conclude we describe future opportunities and challenges for management of wildfire-watershed interactions.

Using community archetypes to better understand differential community adaptation to wildfire risk.

Science.gov (United States)

Carroll, Matthew; Paveglio, Travis

2016-06-05

One of the immediate challenges of wildfire management concerns threats to human safety and property in residential areas adjacent to non-cultivated vegetation. One approach for relieving this problem is to increase human community 'adaptiveness' to deal with the risk and reality of fire in a variety of landscapes. The challenge in creating 'fire-adapted communities' (FACs) is the great diversity in character and make-up of populations at risk from wildfire. This paper outlines a recently developed categorization scheme for Wildland-Urban Interface (WUI) communities based on a larger conceptual approach for understanding how social diversity is likely to influence the creation of FACs. The WUI categorization scheme situates four community archetypes on a continuum that recognizes dynamic change in human community functioning. We use results from the WUI classification scheme to outline key characteristics associated with each archetype and results from recent case studies to demonstrate the diversity across WUI communities. Differences among key characteristics of local social context will likely result in the need for different adaptation strategies to wildfire. While the WUI archetypes described here may not be broadly applicable to other parts of the world, we argue that the conceptual approach and strategies for systematically documenting local influences on wildfire adaptation have potential for broad application.This article is part of the themed issue 'The interaction of fire and mankind'. © 2016 The Author(s).

College's hot topics? Wildfire and Hazards' risk perception among university's population

Science.gov (United States)

Wuerzer, T.

2014-12-01

This research presents a novel perspective on college students and their risk perception in a fire prone US State; Idaho. Idaho was "top #1" in burned lands by acreage in 2012 with approximate 15% of all US burned lands; in 2013 "top #2". Past studies have conducted surveys on residents in high wildfire risk communities to learn what factors make homeowners more likely to engage in mitigation activities and therefore increase communities' resiliency. This research emphasis is on a population that deals with the threat of fire but is likely less invested through property ownership and other investment of risk; yet, equally threatened in quality of life. Are college students the left-out population in the 'planning for wildfires' and its communication process? Main hypothesis is that a college population will have a different perception and awareness (and therefore mitigation actions) than i.e. residents invested in the wild land urban interface (WUI). Dominant research methodologies in past studies are identified as surveys, focus groups, or interviews focusing on homeowners in fire prone areas that have witnessed wildfire or are exposed to increasing fire risk. Yet again, research on population that has no property ownership, investments at stake, and therefore no direct monetary values associated (but potentially non-monetary), is found little to none in these studies. The university population based study and its findings offers a contrast to current literature related to these traditional residents surveys/interviews. The study's survey and interactive spatial assessment of risk perception with allocation of perceived hazards zones promotes understanding of where risk is apparent for participants. Results are used to inform agencies such as campus emergency management, regional wild fire mitigation efforts, and to enhance public communication. Lessons learned include the challenges of a comprehensive inclusion process when mitigating for hazards and building

Evaluation of forest management systems under risk of wildfire

Science.gov (United States)

Kari Hyytiainen; Robert G. Haight

2010-01-01

We evaluate the economic efficiency of even- and uneven-aged management systems under risk of wildfire. The management problems are formulated for a mixed-conifer stand and approximations of the optimal solutions are obtained using simulation optimization. The Northern Idaho variant of the Forest Vegetation Simulator and its Fire and Fuels Extension is used to predict...

Minority Households' Willingness-to-Pay for Public and Private Wildfire Risk Reduction in Florida

Science.gov (United States)

Gonzalez-Caban, A.; Sanchez, J. J.

2017-12-01

The purpose of this work is to estimate willingness-to-pay (WTP) for minority (African-American and Hispanic) homeowners in Florida for private and public wildfire risk reduction programs and also to test for differences in response between the two groups. A random parameter logit and latent class models allowed us to determine if there is difference in wildfire mitigation program preferences, whether WTP is higher for public or private actions for wildfire risk reduction, and whether households with personal experience and who perceive that they live in higher-risk areas have significantly higher WTP. We also compare FL minority homeowners' WTP values with Florida original homeowners' estimates. Results suggest that FL minority homeowners are willing to invest in public programs, with African-Americans WTP values at a higher rate than Hispanics. In addition, the highest priority for cost sharing funds would go to low-income homeowners, especially to cost-share private actions on their own land. These results may help fire managers optimize allocation of scarce cost-sharing funds for public versus private actions.

Living with wildfire in Colorado

Science.gov (United States)

Patricia A. Champ; Nicholas Flores; Hannah Brenkert-Smith

2010-01-01

In this presentation, we describe results of a survey to homeowners living in wildfire-prone areas of two counties along the Front Range of the Rocky Mountains in Colorado. The survey was designed to elicit information on homeowners' experience with wildfire, perceptions of wildfire risk on their property and neighboring properties, mitigation efforts undertaken...

Risk analysis procedure for post-wildfire natural hazards in British Columbia

Science.gov (United States)

Jordan, Peter

2010-05-01

Following a severe wildfire season in 2003, and several subsequent damaging debris flow and flood events, the British Columbia Forest Service developed a procedure for analysing risks to public safety and infrastructure from such events. At the same time, the Forest Service undertook a research program to determine the extent of post-wildfire hazards, and examine the hydrologic and geomorphic processes contributing to the hazards. The risk analysis procedure follows the Canadian Standards Association decision-making framework for risk management (which in turn is based on international standards). This has several steps: identification of risk, risk analysis and estimation, evaluation of risk tolerability, developing control or mitigation strategies, and acting on these strategies. The Forest Service procedure deals only with the first two steps. The results are passed on to authorities such as the Provincial Emergency Program and local government, who are responsible for evaluating risks, warning residents, and applying mitigation strategies if appropriate. The objective of the procedure is to identify and analyse risks to public safety and infrastructure. The procedure is loosely based on the BAER (burned area emergency response) program in the USA, with some important differences. Our procedure focuses on identifying risks and warning affected parties, not on mitigation activities such as broadcast erosion control measures. Partly this is due to limited staff and financial resources. Also, our procedure is not multi-agency, but is limited to wildfires on provincial forest land; in British Columbia about 95% of forest land is in the publicly-owned provincial forest. Each fire season, wildfires are screened by size and proximity to values at risk such as populated areas. For selected fires, when the fire is largely contained, the procedure begins with an aerial reconnaissance of the fire, and photography with a hand-held camera, which can be used to make a

Increased Wildfire Risk Driven by Climate and Development Interactions in the Bolivian Chiquitania, Southern Amazonia.

Science.gov (United States)

Devisscher, Tahia; Anderson, Liana O; Aragão, Luiz E O C; Galván, Luis; Malhi, Yadvinder

2016-01-01

Wildfires are becoming increasingly dominant in tropical landscapes due to reinforcing feedbacks between land cover change and more severe dry conditions. This study focused on the Bolivian Chiquitania, a region located at the southern edge of Amazonia. The extensive, unique and well-conserved tropical dry forest in this region is susceptible to wildfires due to a marked seasonality. We used a novel approach to assess fire risk at the regional level driven by different development trajectories interacting with changing climatic conditions. Possible future risk scenarios were simulated using maximum entropy modelling with presence-only data, combining land cover, anthropogenic and climatic variables. We found that important determinants of fire risk in the region are distance to roads, recent deforestation and density of human settlements. Severely dry conditions alone increased the area of high fire risk by 69%, affecting all categories of land use and land cover. Interactions between extreme dry conditions and rapid frontier expansion further increased fire risk, resulting in potential biomass loss of 2.44±0.8 Tg in high risk area, about 1.8 times higher than the estimates for the 2010 drought. These interactions showed particularly high fire risk in land used for 'extensive cattle ranching', 'agro-silvopastoral use' and 'intensive cattle ranching and agriculture'. These findings have serious implications for subsistence activities and the economy in the Chiquitania, which greatly depend on the forestry, agriculture and livestock sectors. Results are particularly concerning if considering the current development policies promoting frontier expansion. Departmental protected areas inhibited wildfires when strategically established in areas of high risk, even under drought conditions. However, further research is needed to assess their effectiveness accounting for more specific contextual factors. This novel and simple modelling approach can inform fire and land

Wildfire disturbance, erosion and sedimentation risks following the Waldo Canyon Fire in Colorado

Science.gov (United States)

Flint, K.; Kinoshita, A. M.; Chin, A.; Florsheim, J. L.; Nourbakhshbeidokhti, S.

2016-12-01

Wildfire is a landscape-scale disturbance that causes abrupt changes to hydrological responses and sediment flux during subsequent storms. Burning hillslope vegetation during wildfires induces changes to sediment supply and stream flow magnitude. Altered post-fire processes such as channel erosion and sedimentation or flooding enhance downstream hazards that may threaten human populations and physical aquatic habitat over various time scales. Using data from a small drainage basin (Williams Canyon, 4.7 km2) in the Colorado front range burned by the 2012 Waldo Fire as a case study, we investigate post-fire recovery and assess changes in fire-related risks to downstream areas. Our local ground-based precipitation, field measurements, terrestrial Light Detection and Ranging (LiDAR) scanning together with satellite-based remote sensing data (i.e. Landsat) provide a basis for time series analyses of reach-scale erosion and sedimentation response to rainfall patterns as vegetation patterns change following the wildfire. As a first step in quantifying the likelihood and consequences of specific risk scenarios, we examine changes in the combined probability of storm flows and post-fire erosion and sedimentation as vegetation recovers within the study watershed. We explore possible feedbacks and thresholds related to vegetation-hydrology-sediment interactions following wildfire under changing climate regimes. This information is needed to assist in post-fire management to promote sustainability of wildland fluvial systems.

Application of Wildfire Risk Assessment Results to Wildfire Response Planning in the Southern Sierra Nevada, California, USA

Directory of Open Access Journals (Sweden)

Matthew P. Thompson

2016-03-01

Full Text Available How wildfires are managed is a key determinant of long-term socioecological resiliency and the ability to live with fire. Safe and effective response to fire requires effective pre-fire planning, which is the main focus of this paper. We review general principles of effective federal fire management planning in the U.S., and introduce a framework for incident response planning consistent with these principles. We contextualize this framework in relation to a wildland fire management continuum based on federal fire management policy in the U.S. The framework leverages recent advancements in spatial wildfire risk assessment—notably the joint concepts of in situ risk and source risk—and integrates assessment results with additional geospatial information to develop and map strategic response zones. We operationalize this framework in a geographic information system (GIS environment based on landscape attributes relevant to fire operations, and define Potential wildland fire Operational Delineations (PODs as the spatial unit of analysis for strategic response. Using results from a recent risk assessment performed on several National Forests in the Southern Sierra Nevada area of California, USA, we illustrate how POD-level summaries of risk metrics can reduce uncertainty surrounding potential losses and benefits given large fire occurrence, and lend themselves naturally to design of fire and fuel management strategies. To conclude we identify gaps, limitations, and uncertainties, and prioritize future work to support safe and effective incident response.

Probability of ignition - a better approach than ignition margin

International Nuclear Information System (INIS)

Ho, S.K.; Perkins, L.J.

1989-01-01

The use of a figure of merit - the probability of ignition - is proposed for the characterization of the ignition performance of projected ignition tokamaks. Monte Carlo and analytic models have been developed to compute the uncertainty distribution function for ignition of a given tokamak design, in terms of the uncertainties inherent in the tokamak physics database. A sample analysis with this method indicates that the risks of not achieving ignition may be unacceptably high unless the accepted margins for ignition are increased. (author). Letter-to-the-editor. 12 refs, 2 figs, 2 tabs

Increased Wildfire Risk Driven by Climate and Development Interactions in the Bolivian Chiquitania, Southern Amazonia.

Directory of Open Access Journals (Sweden)

Tahia Devisscher

Full Text Available Wildfires are becoming increasingly dominant in tropical landscapes due to reinforcing feedbacks between land cover change and more severe dry conditions. This study focused on the Bolivian Chiquitania, a region located at the southern edge of Amazonia. The extensive, unique and well-conserved tropical dry forest in this region is susceptible to wildfires due to a marked seasonality. We used a novel approach to assess fire risk at the regional level driven by different development trajectories interacting with changing climatic conditions. Possible future risk scenarios were simulated using maximum entropy modelling with presence-only data, combining land cover, anthropogenic and climatic variables. We found that important determinants of fire risk in the region are distance to roads, recent deforestation and density of human settlements. Severely dry conditions alone increased the area of high fire risk by 69%, affecting all categories of land use and land cover. Interactions between extreme dry conditions and rapid frontier expansion further increased fire risk, resulting in potential biomass loss of 2.44±0.8 Tg in high risk area, about 1.8 times higher than the estimates for the 2010 drought. These interactions showed particularly high fire risk in land used for 'extensive cattle ranching', 'agro-silvopastoral use' and 'intensive cattle ranching and agriculture'. These findings have serious implications for subsistence activities and the economy in the Chiquitania, which greatly depend on the forestry, agriculture and livestock sectors. Results are particularly concerning if considering the current development policies promoting frontier expansion. Departmental protected areas inhibited wildfires when strategically established in areas of high risk, even under drought conditions. However, further research is needed to assess their effectiveness accounting for more specific contextual factors. This novel and simple modelling approach can

Globally-Applicable Predictive Wildfire Model   a Temporal-Spatial GIS Based Risk Analysis Using Data Driven Fuzzy Logic Functions

Science.gov (United States)

van den Dool, G.

2017-11-01

This study (van den Dool, 2017) is a proof of concept for a global predictive wildfire model, in which the temporal-spatial characteristics of wildfires are placed in a Geographical Information System (GIS), and the risk analysis is based on data-driven fuzzy logic functions. The data sources used in this model are available as global datasets, but subdivided into three pilot areas: North America (California/Nevada), Europe (Spain), and Asia (Mongolia), and are downscaled to the highest resolution (3-arc second). The GIS is constructed around three themes: topography, fuel availability and climate. From the topographical data, six derived sub-themes are created and converted to a fuzzy membership based on the catchment area statistics. The fuel availability score is a composite of four data layers: land cover, wood loads, biomass, biovolumes. As input for the climatological sub-model reanalysed daily averaged, weather-related data is used, which is accumulated to a global weekly time-window (to account for the uncertainty within the climatological model) and forms the temporal component of the model. The final product is a wildfire risk score (from 0 to 1) by week, representing the average wildfire risk in an area. To compute the potential wildfire risk the sub-models are combined usinga Multi-Criteria Approach, and the model results are validated against the area under the Receiver Operating Characteristic curve.

Improving fire season definition by optimized temporal modelling of daily human-caused ignitions.

Science.gov (United States)

Costafreda-Aumedes, S; Vega-Garcia, C; Comas, C

2018-07-01

Wildfire suppression management is usually based on fast control of all ignitions, especially in highly populated countries with pervasive values-at-risk. To minimize values-at-risk loss by improving response time of suppression resources it is necessary to anticipate ignitions, which are mainly caused by people. Previous studies have found that human-ignition patterns change spatially and temporally depending on socio-economic activities, hence, the deployment of suppression resources along the year should consider these patterns. However, full suppression capacity is operational only within legally established fire seasons, driven by past events and budgets, which limits response capacity and increases damages out of them. The aim of this study was to assess the temporal definition of fire seasons from the perspective of human-ignition patterns for the case study of Spain, where people cause over 95% of fires. Humans engage in activities that use fire as a tool in certain periods within a year, and in locations linked to specific spatial factors. Geographic variables (population, infrastructures, physiography and land uses) were used as explanatory variables for human-ignition patterns. The changing influence of these geographic variables on occurrence along the year was analysed with day-by-day logistic regression models. Daily models were built for all the municipal units in the two climatic regions in Spain (Atlantic and Mediterranean Spain) from 2002 to 2014, and similar models were grouped within continuous periods, designated as ignition-based seasons. We found three ignition-based seasons in the Mediterranean region and five in the Atlantic zones, not coincidental with calendar seasons, but with a high degree of agreement with current legally designated operational fire seasons. Our results suggest that an additional late-winter-early-spring fire season in the Mediterranean area and the extension of this same season in the Atlantic zone should be re

Assessment of Wildfire Risk in Southern California with Live Fuel Moisture Measurement and Remotely Sensed Vegetation Water Content Proxies

Science.gov (United States)

Jia, S.; Kim, S. H.; Nghiem, S. V.; Kafatos, M.

2017-12-01

Live fuel moisture (LFM) is the water content of live herbaceous plants expressed as a percentage of the oven-dry weight of plant. It is a critical parameter in fire ignition in Mediterranean climate and routinely measured in sites selected by fire agencies across the U.S. Vegetation growing cycle, meteorological metrics, soil type, and topography all contribute to the seasonal and inter-annual variation of LFM, and therefore, the risk of wildfire. The optical remote sensing-based vegetation indices (VIs) have been used to estimate the LFM. Comparing to the VIs, microwave remote sensing products have advantages like less saturation effect in greenness and representing the water content of the vegetation cover. In this study, we established three models to evaluate the predictability of LFM in Southern California using MODIS NDVI, vegetation temperature condition index (VTCI) from downscaled Soil Moisture Active Passive (SMAP) products, and vegetation optical depth (VOD) derived by Land Parameter Retrieval Model. Other ancillary variables, such as topographic factors (aspects and slope) and meteorological metrics (air temperature, precipitation, and relative humidity), are also considered in the models. The model results revealed an improvement of LFM estimation from SMAP products and VOD, despite the uncertainties introduced in the downscaling and parameter retrieval. The estimation of LFM using remote sensing data can provide an assessment of wildfire danger better than current methods using NDVI-based growing seasonal index. Future study will test the VOD estimation from SMAP data using the multi-temporal dual channel algorithm (MT-DCA) and extend the LFM modeling to a regional scale.

Using NASA Satellite Observations to Map Wildfire Risk in the United States for Allocation of Fire Management Resources

Science.gov (United States)

Farahmand, A.; Reager, J. T., II; Behrangi, A.; Stavros, E. N.; Randerson, J. T.

2017-12-01

Fires are a key disturbance globally acting as a catalyst for terrestrial ecosystem change and contributing significantly to both carbon emissions and changes in surface albedo. The socioeconomic impacts of wildfire activities are also significant with wildfire activity results in billions of dollars of losses every year. Fire size, area burned and frequency are increasing, thus the likelihood of fire danger, defined by United States National Interagency Fire Center (NFIC) as the demand of fire management resources as a function of how flammable fuels (a function of ignitability, consumability and availability) are from normal, is an important step toward reducing costs associated with wildfires. Numerous studies have aimed to predict the likelihood of fire danger, but few studies use remote sensing data to map fire danger at scales commensurate with regional management decisions (e.g., deployment of resources nationally throughout fire season with seasonal and monthly prediction). Here, we use NASA Gravity Recovery And Climate Experiment (GRACE) assimilated surface soil moisture, NASA Atmospheric Infrared Sounder (AIRS) vapor pressure deficit, NASA Moderate Resolution Imaging Spectroradiometer (MODIS) enhanced vegetation index products and landcover products, along with US Forest Service historical fire activity data to generate probabilistic monthly fire potential maps in the United States. These maps can be useful in not only government operational allocation of fire management resources, but also improving understanding of the Earth System and how it is changing in order to refine predictions of fire extremes.

Risk management plan for the National Ignition Facility

International Nuclear Information System (INIS)

Brereton, S.; Lane, M.; Smith, C.; Yatabe, J.

1998-01-01

The National Ignition Facility (NIF) is a U.S. Department of Energy inertial confinement laser fusion facility, currently under construction at the Lawrence Livermore National Laboratory (LLNL). NIF is a critical tool for the Department of Energy (DOE) science- based Stockpile Stewardship and Management Program. In addition, it represents a major step towards realizing inertial confinement fusion as a source of energy. The NIF will focus 192 laser beams onto spherical targets containing a mixture of deuterium and tritium, causing them to implode. This will create the high temperatures and pressures necessary for these targets to undergo fusion. The plan is for NIF to achieve ignition (i.e., self-heating of the fuel) and energy gain (i.e., more fusion energy produced than laser energy deposited) in the laboratory for the first time. A Risk Management Plan was prepared for the NIF design and construction Project. The plan was prepared in accordance with the DOE Life Cycle Asset Management Good Practice Guide. The objectives of the plan were to: (1) identify the risks to the completion of the Project in terms of meeting technical and regulatory requirements, cost, and schedule, (2) assess the risks in terms of likelihood of occurrence and their impact potential relative to technical performance, ES ampersand H (environment, safety and health), costs, and schedule, and (3) address each risk in terms of suitable risk management measures. Major risk elements were identified for the NIF Project. A risk assessment methodology was developed, which was utilized to rank the Project risks with respect to one another. Those elements presenting greater risk were readily identified by this process. This paper describes that methodology and the results

Measuring the efficacy of a wildfire education program in Colorado Springs.

Science.gov (United States)

G.H. Donovan; P.A. Champ; D.T. Butry

2007-01-01

We examine an innovative wildfire risk education program in Colorado Springs, which rated the wildfire risk of 35,000 homes in the city's wildland urban interface. Evidence from home sales before and after the program's implementation suggests that the program was successful at changing homebuyers' attitudes toward wildfire risk, particularly preferences...

Predicting Geomorphic and Hydrologic Risks after Wildfire Using Harmonic and Stochastic Analyses

Science.gov (United States)

Mikesell, J.; Kinoshita, A. M.; Florsheim, J. L.; Chin, A.; Nourbakhshbeidokhti, S.

2017-12-01

Wildfire is a landscape-scale disturbance that often alters hydrological processes and sediment flux during subsequent storms. Vegetation loss from wildfires induce changes to sediment supply such as channel erosion and sedimentation and streamflow magnitude or flooding. These changes enhance downstream hazards, threatening human populations and physical aquatic habitat over various time scales. Using Williams Canyon, a basin burned by the Waldo Canyon Fire (2012) as a case study, we utilize deterministic and statistical modeling methods (Fourier series and first order Markov chain) to assess pre- and post-fire geomorphic and hydrologic characteristics, including of precipitation, enhanced vegetation index (EVI, a satellite-based proxy of vegetation biomass), streamflow, and sediment flux. Local precipitation, terrestrial Light Detection and Ranging (LiDAR) scanning, and satellite-based products are used for these time series analyses. We present a framework to assess variability of periodic and nonperiodic climatic and multivariate trends to inform development of a post-wildfire risk assessment methodology. To establish the extent to which a wildfire affects hydrologic and geomorphic patterns, a Fourier series was used to fit pre- and post-fire geomorphic and hydrologic characteristics to yearly temporal cycles and subcycles of 6, 4, 3, and 2.4 months. These cycles were analyzed using least-squares estimates of the harmonic coefficients or amplitudes of each sub-cycle's contribution to fit the overall behavior of a Fourier series. The stochastic variances of these characteristics were analyzed by composing first-order Markov models and probabilistic analysis through direct likelihood estimates. Preliminary results highlight an increased dependence of monthly post-fire hydrologic characteristics on 12 and 6-month temporal cycles. This statistical and probabilistic analysis provides a basis to determine the impact of wildfires on the temporal dependence of

Coupling of Bayesian Networks with GIS for wildfire risk assessment on natural and agricultural areas of the Mediterranean

Science.gov (United States)

Scherb, Anke; Papakosta, Panagiota; Straub, Daniel

2014-05-01

Wildfires cause severe damages to ecosystems, socio-economic assets, and human lives in the Mediterranean. To facilitate coping with wildfire risks, an understanding of the factors influencing wildfire occurrence and behavior (e.g. human activity, weather conditions, topography, fuel loads) and their interaction is of importance, as is the implementation of this knowledge in improved wildfire hazard and risk prediction systems. In this project, a probabilistic wildfire risk prediction model is developed, with integrated fire occurrence and fire propagation probability and potential impact prediction on natural and cultivated areas. Bayesian Networks (BNs) are used to facilitate the probabilistic modeling. The final BN model is a spatial-temporal prediction system at the meso scale (1 km2 spatial and 1 day temporal resolution). The modeled consequences account for potential restoration costs and production losses referred to forests, agriculture, and (semi-) natural areas. BNs and a geographic information system (GIS) are coupled within this project to support a semi-automated BN model parameter learning and the spatial-temporal risk prediction. The coupling also enables the visualization of prediction results by means of daily maps. The BN parameters are learnt for Cyprus with data from 2006-2009. Data from 2010 is used as validation data set. A special focus is put on the performance evaluation of the BN for fire occurrence, which is modeled as binary classifier and thus, could be validated by means of Receiver Operator Characteristic (ROC) curves. With the final best models, AUC values of more than 70% for validation could be achieved, which indicates potential for reliable prediction performance via BN. Maps of selected days in 2010 are shown to illustrate final prediction results. The resulting system can be easily expanded to predict additional expected damages in the mesoscale (e.g. building and infrastructure damages). The system can support planning of

Exploring how alternative mapping approaches influence fireshed assessment and human community exposure to wildfire

Science.gov (United States)

Joe H. Scott; Matthew P. Thompson; Julie W. Gilbertson-Day

2015-01-01

Attaining fire-adapted human communities has become a key focus of collaborative planning on landscapes across the western United States and elsewhere. The coupling of fire simulation with GIS has expanded the analytical base to support such planning efforts, particularly through the "fireside" concept that identifies areas where wildfires could ignite and...

Measures to suppress ignition risk on full-face heading machines

Energy Technology Data Exchange (ETDEWEB)

Seeliger, A; Marx, W -E; Radtke, H

1987-12-01

Within the Research Development project 'Measures to suppress ignition risk on full-facers' the Institute of Mechanical Engineering of the Westfaelische Berggewerkskasse (WBK) has formulated concepts to reduce the ignition danger caused by the cutting action of full-face heading machines. Since the cooling of the rock surface in the immediate vicinity of the roller bits represents an effective preventive measure against ignition of firedamp, the machine manufacturers recommend the installation of a nozzle close to each disc holder whose water jet hits the point immediately behind and on the roller bit itself. The shape of nozzles to be employed should be such that they generate a water jet whose fan is capable of creating air velocities of about 10 m/s along the cutting track of the roller bits. This will achieve an additional degree of safety from ignition of any firedamp that may be present, because the duration of a juxtaposition between a possible hot surface and firedamp for energy exchange is reduced. The water could be fed to the individual nozzles at a pressure of 60 to 80 bar through a rotary distributor in the borer head. Following an analysis of the most frequent ignition causes a rotation and temperature monitoring system was developed for the roller bits of a borer head. 5 figs.

Locating Spatial Variation in the Association Between Wildland Fire Risk and Social Vulnerability Across Six Southern States

Science.gov (United States)

Poudyal, Neelam C.; Johnson-Gaither, Cassandra; Goodrick, Scott; Bowker, J. M.; Gan, Jianbang

2012-03-01

Wildland fire in the South commands considerable attention, given the expanding wildland urban interface (WUI) across the region. Much of this growth is propelled by higher income retirees and others desiring natural amenity residential settings. However, population growth in the WUI increases the likelihood of wildfire fire ignition caused by people, as humans account for 93% of all wildfires fires in the South. Coexisting with newly arrived, affluent WUI populations are working class, poor or otherwise socially vulnerable populations. The latter groups typically experience greater losses from environmental disasters such as wildfire because lower income residents are less likely to have established mitigation programs in place to help absorb loss. We use geographically weighted regression to examine spatial variation in the association between social vulnerability (SOVUL) and wildfire risk. In doing so, we identify "hot spots" or geographical clusters where SOVUL varies positively with wildfire risk across six Southern states—Alabama, Arkansas, Florida, Georgia, Mississippi, and South Carolina. These clusters may or may not be located in the WUI. These hot spots are most prevalent in South Carolina and Florida. Identification of these population clusters can aid wildfire managers in deciding which communities to prioritize for mitigation programming.

Decision making for wildfires: A guide for applying a risk management process at the incident level

Science.gov (United States)

Mary A. Taber; Lisa M. Elenz; Paul G. Langowski

2013-01-01

This publication focuses on the thought processes and considerations surrounding a risk management process for decision making on wildfires. The publication introduces a six element risk management cycle designed to encourage sound risk-informed decision making in accordance with Federal wildland fire policy, although the process is equally applicable to non-Federal...

Wildfire Policy in Mediterranean France: How Far is it Efficient and Sustainable?

Science.gov (United States)

Curt, Thomas; Frejaville, Thibaut

2018-03-01

A new fire policy reinforcing aggressive fire suppression was established in Mediterranean France in response to the devastating wildfires of the 1990s, but to what extent this has changed fire activity yet remains poorly understood. For this purpose, we compared the number and location of ignitions and of burned areas between two 20-year periods (1975-1994 vs. 1995-2014), in parallel to the changes in fuel covering, human activity promoting ignitions, and fire weather. The number of fires decreased almost continuously since 1975, but sharply after 1994, suggesting an effect of better fire prevention due to the new policy. But the major change in fire activity is a considerable reduction in fire size and burned areas after 1994, especially during summer and in the most fire-prone places, in response to massive efforts put into fire suppression. These reductions have occurred while the covering by fuel biomass, the human pressure on ignition, and the fire weather index increased, thus making the study area more hazardous. Our results suggest that a strategy of aggressive fire suppression has great potential for counterbalancing the effects of climate changes and human activities and for controlling fire activity in the short term. However, we discuss whether such a suppression-oriented approach is sustainable in the context of global changes, which cast new fire challenges as demonstrated by the devastative fires of 2003 and 2016. We advocate for a more comprehensive fire policy to come. © 2017 Society for Risk Analysis.

Quantification of annual wildfire risk; A spatio-temporal point process approach.

Directory of Open Access Journals (Sweden)

Paula Pereira

2013-10-01

Full Text Available Policy responses for local and global firemanagement depend heavily on the proper understanding of the fire extent as well as its spatio-temporal variation across any given study area. Annual fire risk maps are important tools for such policy responses, supporting strategic decisions such as location-allocation of equipment and human resources. Here, we define risk of fire in the narrow sense as the probability of its occurrence without addressing the loss component. In this paper, we study the spatio-temporal point patterns of wildfires and model them by a log Gaussian Cox processes. Themean of predictive distribution of randomintensity function is used in the narrow sense, as the annual fire risk map for next year.

Creating a spatially-explicit index: a method for assessing the global wildfire-water risk

Science.gov (United States)

Robinne, François-Nicolas; Parisien, Marc-André; Flannigan, Mike; Miller, Carol; Bladon, Kevin D.

2017-04-01

The wildfire-water risk (WWR) has been defined as the potential for wildfires to adversely affect water resources that are important for downstream ecosystems and human water needs for adequate water quantity and quality, therefore compromising the security of their water supply. While tools and methods are numerous for watershed-scale risk analysis, the development of a toolbox for the large-scale evaluation of the wildfire risk to water security has only started recently. In order to provide managers and policy-makers with an adequate tool, we implemented a method for the spatial analysis of the global WWR based on the Driving forces-Pressures-States-Impacts-Responses (DPSIR) framework. This framework relies on the cause-and-effect relationships existing between the five categories of the DPSIR chain. As this approach heavily relies on data, we gathered an extensive set of spatial indicators relevant to fire-induced hydrological hazards and water consumption patterns by human and natural communities. When appropriate, we applied a hydrological routing function to our indicators in order to simulate downstream accumulation of potentially harmful material. Each indicator was then assigned a DPSIR category. We collapsed the information in each category using a principal component analysis in order to extract the most relevant pixel-based information provided by each spatial indicator. Finally, we compiled our five categories using an additive indexation process to produce a spatially-explicit index of the WWR. A thorough sensitivity analysis has been performed in order to understand the relationship between the final risk values and the spatial pattern of each category used during the indexation. For comparison purposes, we aggregated index scores by global hydrological regions, or hydrobelts, to get a sense of regional DPSIR specificities. This rather simple method does not necessitate the use of complex physical models and provides a scalable and efficient tool

Wildfires and tourist behaviors in Florida

Science.gov (United States)

Brijesh Thapa; Ignatius Cahyanto; Stephen M. Holland; James D. Absher

2013-01-01

The impacts of wildfires on tourism have largely been examined with emphasis on economic losses and recovery strategies. Given the limited research from a demand perspective, this study examined tourist risk perceptions and reactionary behaviors toward wildfires in Florida. Data (N ¼ 771) was collected among a U.S. sample of non-resident overnight leisure travelers...

Capacity to adapt to environmental change: evidence from a network of organizations concerned with increasing wildfire risk

Directory of Open Access Journals (Sweden)

A. Paige. Fischer

2017-03-01

Full Text Available Because wildfire size and frequency are expected to increase in many forested areas in the United States, organizations involved in forest and wildfire management could arguably benefit from working together and sharing information to develop strategies for how to adapt to this increasing risk. Social capital theory suggests that actors in cohesive networks are positioned to build trust and mutual understanding of problems and act collectively to address these problems, and that actors engaged with diverse partners are positioned to access new information and resources that are important for innovation and complex problem solving. We investigated the patterns of interaction within a network of organizations involved in forest and wildfire management in Oregon, USA, for evidence of structural conditions that create opportunities for collective action and learning. We used descriptive statistical analysis of social network data gathered through interviews to characterize the structure of the network and exponential random graph modeling to identify key factors in the formation of network ties. We interpreted our findings through the lens of social capital theory to identify implications for the network's capacity to engage in collective action and complex problem-solving about how to adapt to environmental change. We found that tendencies to associate with others with similar management goals, geographic emphases, and attitudes toward wildfire were strong mechanisms shaping network structure, potentially constraining interactions among organizations with diverse information and resources and limiting opportunities for learning and complex problem-solving needed for adaptation. In particular, we found that organizations with fire protection and forest restoration goals comprised distinct networks despite sharing concern about the problem of increasing wildfire risk.

Modelling of spatial prediction of fire ignition risk in the Antalya-Manavgat district

Directory of Open Access Journals (Sweden)

Coşkun Okan Güney

2016-07-01

Full Text Available The aim of this study was to present the fire ignition risk for Manavgat-Antalya District to enable the planning of firefighting sources in a more qualified way. From sites within the study area, where forest fires broke out or not during the past five years, we obtained geographical coordinates, climate data, topographical data and variables like bedrock, stand types, settlement areas, roads and power lines and prepared them with geographical information systems. For all variables we performed Wilcoxon rank-sum test, interspecific correlation analysis and logistic regression analysis and obtained 4 different models. When ROC analysis was applied to these models, model 4 was determined as the most significant model and therefore used to prepare the fire ignition risk map for the Manavgat-Antalya District. According to this map, ignition risk within the study area was highest in and around settlement areas where roads and power lines concentrate and Turkish red pine is distributed, but it was lowest afar of settlement areas without roads and where species apart from Turkish red pine are distributed. According to the results some suggestions were made.

Experimental investigations of the minimum ignition energy and the minimum ignition temperature of inert and combustible dust cloud mixtures

Energy Technology Data Exchange (ETDEWEB)

Addai, Emmanuel Kwasi, E-mail: emmanueladdai41@yahoo.com; Gabel, Dieter; Krause, Ulrich

2016-04-15

Highlights: • Ignition sensitivity of a highly flammable dust decreases upon addition of inert dust. • Minimum ignition temperature of a highly flammable dust increases when inert concentration increase. • Minimum ignition energy of a highly flammable dust increases when inert concentration increase. • The permissible range for the inert mixture to minimize the ignition risk lies between 60 to 80%. - Abstract: The risks associated with dust explosions still exist in industries that either process or handle combustible dust. This explosion risk could be prevented or mitigated by applying the principle of inherent safety (moderation). This is achieved by adding an inert material to a highly combustible material in order to decrease the ignition sensitivity of the combustible dust. The presented paper deals with the experimental investigation of the influence of adding an inert dust on the minimum ignition energy and the minimum ignition temperature of the combustible/inert dust mixtures. The experimental investigation was done in two laboratory scale equipment: the Hartmann apparatus and the Godbert-Greenwald furnace for the minimum ignition energy and the minimum ignition temperature test respectively. This was achieved by mixing various amounts of three inert materials (magnesium oxide, ammonium sulphate and sand) and six combustible dusts (brown coal, lycopodium, toner, niacin, corn starch and high density polyethylene). Generally, increasing the inert materials concentration increases the minimum ignition energy as well as the minimum ignition temperatures until a threshold is reached where no ignition was obtained. The permissible range for the inert mixture to minimize the ignition risk lies between 60 to 80%.

Experimental investigations of the minimum ignition energy and the minimum ignition temperature of inert and combustible dust cloud mixtures

International Nuclear Information System (INIS)

Addai, Emmanuel Kwasi; Gabel, Dieter; Krause, Ulrich

2016-01-01

Highlights: • Ignition sensitivity of a highly flammable dust decreases upon addition of inert dust. • Minimum ignition temperature of a highly flammable dust increases when inert concentration increase. • Minimum ignition energy of a highly flammable dust increases when inert concentration increase. • The permissible range for the inert mixture to minimize the ignition risk lies between 60 to 80%. - Abstract: The risks associated with dust explosions still exist in industries that either process or handle combustible dust. This explosion risk could be prevented or mitigated by applying the principle of inherent safety (moderation). This is achieved by adding an inert material to a highly combustible material in order to decrease the ignition sensitivity of the combustible dust. The presented paper deals with the experimental investigation of the influence of adding an inert dust on the minimum ignition energy and the minimum ignition temperature of the combustible/inert dust mixtures. The experimental investigation was done in two laboratory scale equipment: the Hartmann apparatus and the Godbert-Greenwald furnace for the minimum ignition energy and the minimum ignition temperature test respectively. This was achieved by mixing various amounts of three inert materials (magnesium oxide, ammonium sulphate and sand) and six combustible dusts (brown coal, lycopodium, toner, niacin, corn starch and high density polyethylene). Generally, increasing the inert materials concentration increases the minimum ignition energy as well as the minimum ignition temperatures until a threshold is reached where no ignition was obtained. The permissible range for the inert mixture to minimize the ignition risk lies between 60 to 80%.

Preventing erosive risks after wildfire in Spain: advances and gaps

Science.gov (United States)

Fernández Filgueira, Cristina; Vega Hidalgo, José A.; Fontúrbel Lliteras, Teresa

2017-04-01

Galicia (NW Spain) is one of the most wildfire-affected areas in Western Europe and where the highest soil losses following fire are recorded in the Iberian Peninsula. During the last decade, mitigation of hydrological and erosive risk has been an important objective for researchers and forest managers. For this reason, research carried out has focused on three main issues: i) the development of operational tools to prioritize post-fire soil stabilization actions, based on soil burn severity indicators and remote sensed information, and testing of their ability to reflect degradation risk in relevant soil properties and subsequent soil erosion, ii) the development and testing of different soil stabilization treatments and their effectiveness for reducing erosion, following their application at broad scale, under the specific environmental conditions of Galicia and iii) the assessment of the performance of current erosion models as well as the development of empirical models to predict post-fire soil losses. On the other hand, the use of forest resources is an essential component of the regional incomes in NW Spain and consequently there is a pressing necessity for investigation on techniques suitable for reconciling soil conservation and sustainable use of those resources. In the framework of wildfire impacts this involve many and complex challenges. This scenario contrast with most of the Iberian Peninsula under Mediterranean influence where salvage logging is not a priority. As in other regions, post-fire hydrologic and erosive risk modeling, including threatened resources vulnerability evaluation is also a capital research need, particularly in a climate change context where dramatic changes in drivers such as precipitation, evapotranspiration and fire regime are expected. The study was funded by the National Institute of Agricultural Research of Spain (INIA) through project RTA2014-00011-C06-02, cofunded by FEDER and the Plan de Mejora e Innovación Forestal de

Managing wildfire events: risk-based decision making among a group of federal fire managers

Science.gov (United States)

Robyn S. Wilson; Patricia L. Winter; Lynn A. Maguire; Timothy. Ascher

2011-01-01

Managing wildfire events to achieve multiple management objectives involves a high degree of decision complexity and uncertainty, increasing the likelihood that decisions will be informed by experience-based heuristics triggered by available cues at the time of the decision. The research reported here tests the prevalence of three risk-based biases among 206...

Wildfires and post-fire erosion risk in a coastal area under severe anthropic pressure associated with the touristic fluxes

Science.gov (United States)

Canu, Annalisa; Arca, Bachisio; Pellizzaro, Grazia; Valeriano Pintus, Gian; Ferrara, Roberto; Duce, Pierpaolo

2017-04-01

In the last decades a rapid and intense development of the tourism industry led to an increasing of anthropic pressure on several coastal areas of Sardinia. This fact not only modified the coastal aesthetics, but has also generated an increase of risk for the environment. This phenomenon affected also the ancient structure of the landscape with a negative impact mainly caused by the following factors: land abandonment, wildfire occurrence, post-fire erosion, urbanization. These regional changes can be analyzed in detail by considering the geo-diachronic dynamics. The main objectives of this work were i) to perform a diachronic analysis of land use and land cover dynamics, ii) to analyse the recent dynamics of wildfires, and iii) to predict the soil erosion risk in relation to land use change occurred between the 1950s and the 2000s. The study was realized in a coastal area located in North-East Sardinia where the geo-historical processes were summarized and organized in a geographic information system that has been employed to examine the landscape variations at three different time steps: 1954, 1977 and 2000. In addition, different scenarios of wildfire propagation were simulated by FlamMap in order to estimate the spatial pattern of fire danger factors in the study area. Afterwards, maps of post-fire soil erosion were produced to identify the temporal and spatial variations of the erosion risk. The results show how the changes in land use and the significant and rapid increase of the residential areas affect the risk of both wildfires and post-fire soil erosion. The study reveals the capabilities of this type of approach and can be used by management agencies and policy makers e in sustainable landscape management planning. This approach can be extended to other regions of the Mediterranean basin characterized by complex interactions among landscape and anthropic factors affecting the environmental risk.

Examining Atmospheric and Ecological Drivers of Wildfires, Modeling Wildfire Occurrence in the Southwest United States, and Using Atmospheric Sounding Observations to Verify National Weather Service Spot Forecasts

Science.gov (United States)

Nauslar, Nicholas J.

This dissertation is comprised of three different papers that all pertain to wildland fire applications. The first paper performs a verification analysis on mixing height, transport winds, and Haines Index from National Weather Service spot forecasts across the United States. The final two papers, which are closely related, examine atmospheric and ecological drivers of wildfire for the Southwest Area (SWA) (Arizona, New Mexico, west Texas, and Oklahoma panhandle) to better equip operational fire meteorologists and managers to make informed decisions on wildfire potential in this region. The verification analysis here utilizes NWS spot forecasts of mixing height, transport winds and Haines Index from 2009-2013 issued for a location within 50 km of an upper sounding location and valid for the day of the fire event. Mixing height was calculated from the 0000 UTC sounding via the Stull, Holzworth, and Richardson methods. Transport wind speeds were determined by averaging the wind speed through the boundary layer as determined by the three mixing height methods from the 0000 UTC sounding. Haines Index was calculated at low, mid, and high elevation based on the elevation of the sounding and spot forecast locations. Mixing height forecasts exhibited large mean absolute errors and biased towards over forecasting. Forecasts of transport wind speeds and Haines Index outperformed mixing height forecasts with smaller errors relative to their respective means. The rainfall and lightning associated with the North American Monsoon (NAM) can vary greatly intra- and inter-annually and has a large impact on wildfire activity across the SWA by igniting or suppressing wildfires. NAM onset thresholds and subsequent dates are determined for the SWA and each Predictive Service Area (PSA), which are sub-regions used by operational fire meteorologists to predict wildfire potential within the SWA, April through September from 1995-2013. Various wildfire activity thresholds using the number

Wildfire air pollution hazard during the 21st century

Science.gov (United States)

Knorr, Wolfgang; Dentener, Frank; Lamarque, Jean-François; Jiang, Leiwen; Arneth, Almut

2017-07-01

Wildfires pose a significant risk to human livelihoods and are a substantial health hazard due to emissions of toxic smoke. Previous studies have shown that climate change, increasing atmospheric CO2, and human demographic dynamics can lead to substantially altered wildfire risk in the future, with fire activity increasing in some regions and decreasing in others. The present study re-examines these results from the perspective of air pollution risk, focussing on emissions of airborne particulate matter (PM2. 5), combining an existing ensemble of simulations using a coupled fire-dynamic vegetation model with current observation-based estimates of wildfire emissions and simulations with a chemical transport model. Currently, wildfire PM2. 5 emissions exceed those from anthropogenic sources in large parts of the world. We further analyse two extreme sets of future wildfire emissions in a socio-economic, demographic climate change context and compare them to anthropogenic emission scenarios reflecting current and ambitious air pollution legislation. In most regions of the world, ambitious reductions of anthropogenic air pollutant emissions have the potential to limit mean annual pollutant PM2. 5 levels to comply with World Health Organization (WHO) air quality guidelines for PM2. 5. Worst-case future wildfire emissions are not likely to interfere with these annual goals, largely due to fire seasonality, as well as a tendency of wildfire sources to be situated in areas of intermediate population density, as opposed to anthropogenic sources that tend to be highest at the highest population densities. However, during the high-fire season, we find many regions where future PM2. 5 pollution levels can reach dangerous levels even for a scenario of aggressive reduction of anthropogenic emissions.

Integrating pixel- and polygon-based approaches to wildfire risk assessment: Application to a high-value watershed on the Pike and San Isabel National Forests, Colorado, USA

Science.gov (United States)

Matthew P. Thompson; Julie W. Gilbertson-Day; Joe H. Scott

2015-01-01

We develop a novel risk assessment approach that integrates complementary, yet distinct, spatial modeling approaches currently used in wildfire risk assessment. Motivation for this work stems largely from limitations of existing stochastic wildfire simulation systems, which can generate pixel-based outputs of fire behavior as well as polygon-based outputs of simulated...

Research and development supporting risk-based wildfire effects prediction for fuels and fire management: Status and needs

Science.gov (United States)

Kevin Hyde; Matthew B. Dickinson; Gil Bohrer; David Calkin; Louisa Evers; Julie Gilbertson-Day; Tessa Nicolet; Kevin Ryan; Christina Tague

2013-01-01

Wildland fire management has moved beyond a singular focus on suppression, calling for wildfire management for ecological benefit where no critical human assets are at risk. Processes causing direct effects and indirect, long-term ecosystem changes are complex and multidimensional. Robust risk-assessment tools are required that account for highly variable effects on...

ArcFuels: an ArcMap toolbar for fuel treatment planning and wildfire risk assessment

Science.gov (United States)

Nicole M. Vaillant; Alan A. Ager

2014-01-01

Fire behavior modeling and geospatial analysis can provide tremendous insight to land managers in defining both the benefits and potential impacts of fuel treatments in the context of land management goals and public expectations. ArcFuels is a streamlined fuel management planning and wildfire risk assessment system that creates a trans-scale (stand to large landscape...

Analyzing wildfire exposure on Sardinia, Italy

Science.gov (United States)

Salis, Michele; Ager, Alan A.; Arca, Bachisio; Finney, Mark A.; Alcasena, Fermin; Bacciu, Valentina; Duce, Pierpaolo; Munoz Lozano, Olga; Spano, Donatella

2014-05-01

We used simulation modeling based on the minimum travel time algorithm (MTT) to analyze wildfire exposure of key ecological, social and economic features on Sardinia, Italy. Sardinia is the second largest island of the Mediterranean Basin, and in the last fifty years experienced large and dramatic wildfires, which caused losses and threatened urban interfaces, forests and natural areas, and agricultural productions. Historical fires and environmental data for the period 1995-2009 were used as input to estimate fine scale burn probability, conditional flame length, and potential fire size in the study area. With this purpose, we simulated 100,000 wildfire events within the study area, randomly drawing from the observed frequency distribution of burn periods and wind directions for each fire. Estimates of burn probability, excluding non-burnable fuels, ranged from 0 to 1.92x10-3, with a mean value of 6.48x10-5. Overall, the outputs provided a quantitative assessment of wildfire exposure at the landscape scale and captured landscape properties of wildfire exposure. We then examined how the exposure profiles varied among and within selected features and assets located on the island. Spatial variation in modeled outputs resulted in a strong effect of fuel models, coupled with slope and weather. In particular, the combined effect of Mediterranean maquis, woodland areas and complex topography on flame length was relevant, mainly in north-east Sardinia, whereas areas with herbaceous fuels and flat areas were in general characterized by lower fire intensity but higher burn probability. The simulation modeling proposed in this work provides a quantitative approach to inform wildfire risk management activities, and represents one of the first applications of burn probability modeling to capture fire risk and exposure profiles in the Mediterranean basin.

Evaluating Alternative Prescribed Burning Policies to Reduce Net Economic Damages from Wildfire

OpenAIRE

D. Evan Mercer; Jeffrey P. Prestemon; David T. Butry; John M. Pye

2007-01-01

We estimate a wildfire risk model with a new measure of wildfire output, intensity-weighted risk and use it in Monte Carlo simulations to estimate welfare changes from alternative prescribed burning policies. Using Volusia County, Florida as a case study, an annual prescribed burning rate of 13% of all forest lands maximizes net welfare; ignoring the effects on wildfire intensity may underestimate optimal rates of prescribed burning. Our estimated supply function for prescribed fire services ...

Experimental investigations of the minimum ignition energy and the minimum ignition temperature of inert and combustible dust cloud mixtures.

Science.gov (United States)

Addai, Emmanuel Kwasi; Gabel, Dieter; Krause, Ulrich

2016-04-15

The risks associated with dust explosions still exist in industries that either process or handle combustible dust. This explosion risk could be prevented or mitigated by applying the principle of inherent safety (moderation). This is achieved by adding an inert material to a highly combustible material in order to decrease the ignition sensitivity of the combustible dust. The presented paper deals with the experimental investigation of the influence of adding an inert dust on the minimum ignition energy and the minimum ignition temperature of the combustible/inert dust mixtures. The experimental investigation was done in two laboratory scale equipment: the Hartmann apparatus and the Godbert-Greenwald furnace for the minimum ignition energy and the minimum ignition temperature test respectively. This was achieved by mixing various amounts of three inert materials (magnesium oxide, ammonium sulphate and sand) and six combustible dusts (brown coal, lycopodium, toner, niacin, corn starch and high density polyethylene). Generally, increasing the inert materials concentration increases the minimum ignition energy as well as the minimum ignition temperatures until a threshold is reached where no ignition was obtained. The permissible range for the inert mixture to minimize the ignition risk lies between 60 to 80%. Copyright © 2016 Elsevier B.V. All rights reserved.

Target design for shock ignition

International Nuclear Information System (INIS)

Schurtz, G; Ribeyre, X; Lafon, M

2010-01-01

The conventional approach of laser driven inertial fusion involves the implosion of cryogenic shells of deuterium-tritium ice. At sufficiently high implosion velocities, the fuel ignites by itself from a central hot spot. In order to reduce the risks of hydrodynamic instabilities inherent to large implosion velocities, it was proposed to compress the fuel at low velocity, and ignite the compressed fuel by means of a convergent shock wave driven by an intense spike at the end of the laser pulse. This scheme, known as shock ignition, reduces the risks of shell break-up during the acceleration phase, but it may be impeded by a low coupling efficiency of the laser pulse with plasma at high intensities. This work provides a relationship between the implosion velocity and the laser intensity required to ignite the target by a shock. The operating domain of shock ignition at different energies is described.

Wildfire risk reduction in the United States: Leadership staff perceptions of local fire department roles and responsibilities

Science.gov (United States)

Rachel S. Madsen; Hylton J. G. Haynes; Sarah M. McCaffrey

2018-01-01

As wildland fires have had increasing negative impacts on a range of human values, in many parts of the United States (U.S.) and around the world, collaborative risk reduction efforts among agencies, homeowners, and fire departments are needed to improve wildfire safety and mitigate risk. Using interview data from 46 senior officers from local fire departments around...

Assessing Climate Change Impacts on Wildfire Exposure in Mediterranean Areas.

Science.gov (United States)

Lozano, Olga M; Salis, Michele; Ager, Alan A; Arca, Bachisio; Alcasena, Fermin J; Monteiro, Antonio T; Finney, Mark A; Del Giudice, Liliana; Scoccimarro, Enrico; Spano, Donatella

2017-10-01

We used simulation modeling to assess potential climate change impacts on wildfire exposure in Italy and Corsica (France). Weather data were obtained from a regional climate model for the period 1981-2070 using the IPCC A1B emissions scenario. Wildfire simulations were performed with the minimum travel time fire spread algorithm using predicted fuel moisture, wind speed, and wind direction to simulate expected changes in weather for three climatic periods (1981-2010, 2011-2040, and 2041-2070). Overall, the wildfire simulations showed very slight changes in flame length, while other outputs such as burn probability and fire size increased significantly in the second future period (2041-2070), especially in the southern portion of the study area. The projected changes fuel moisture could result in a lengthening of the fire season for the entire study area. This work represents the first application in Europe of a methodology based on high resolution (250 m) landscape wildfire modeling to assess potential impacts of climate changes on wildfire exposure at a national scale. The findings can provide information and support in wildfire management planning and fire risk mitigation activities. © 2016 Society for Risk Analysis.

Israel wildfires: future trends, impacts and mitigation strategies

Science.gov (United States)

Wittenberg, Lea

2017-04-01

Forest fires in the Euro-Mediterranean region burn about 450,000 ha each year. In Israel, the frequency and extent of wildfires have been steadily increasing over the past decades, culminating in several large and costly fires in 2010, 2012 and 2016. The extensive development of forest areas since the 1950's and the accumulation of fuel in the forests, has led to increased occurrences of high intensity fires. Land-use changes and human population growth are the most prevailing and common determinant of wildfire occurrence and impacts. Climate extremes, possibly already a sign of regional climate change, are another frequent determinant of increasing wildfire risk. Therefore, the combination of extreme dry spells, high fuel loads and increased anthropogenic pressure on the open spaces result in an overall amplified wildfire risk. These fires not only cause loss of life and damage to properties but also carry serious environmental repercussions. Combustion of standing vegetation and the leaf litter leave the soil bare and vulnerable to runoff and erosion, thereby increasing risks of flooding. Today, all of Israel's open spaces, forests, natural parks, major metropolitan centers, towns and villages are embedded within the wildland urban interface (WUI). Typically, wildfires near or in the WUI occur on uplands and runoff generated from the burned area poses flooding risks in urban and agricultural zones located downstream. Post-fire management aims at reducing associated hazards as collapsing trees and erosion risk. Often the time interval between a major fire and the definition of priority sites is in the order of days-to-weeks since administrative procedures, financial estimates and implementation of post-fire salvage logging operations require time. Defining the magnitude of the burn scar and estimating its potential impact on runoff and erosion must therefore be done quickly. A post-fire burn severity, runoff and erosion model is a useful tool in estimating

Examining alternative fuel management strategies and the relative contribution of National Forest System land to wildfire risk to adjacent homes - A pilot assessment on the Sierra National Forest, California, USA

Science.gov (United States)

Joe H. Scott; Matthew P. Thompson; Julie W. Gilbertson-Day

2016-01-01

Determining the degree of risk that wildfires pose to homes, where across the landscape the risk originates, and who can best mitigate risk are integral elements of effective co-management of wildfire risk. Developing assessments and tools to help provide this information is a high priority for federal land management agencies such as the US Forest Service (...

Comparing resource values at risk from wildfires with Forest Service fire suppression expenditures: Examples from 2003 western Montana wildfire season

Science.gov (United States)

David Calkin; Kevin Hyde; Krista Gebert; Greg Jones

2005-01-01

Determining the economic effectiveness of wildfire suppression activities is complicated by difficulties in identifying the area that would have burned and the associated resource value changes had suppression resources not been employed. We developed a case study using break-even analysis for two large wildfires from the 2003 fire season in western Montana -- the...

Does personal experience affect choice-based preferences for wildfire protection programs?

Science.gov (United States)

Armando González-Cabán; Thomas P. Holmes; John B. Loomis; José J. Sánchez

2013-01-01

In this paper, we investigate homeowner preferences and willingness to pay for wildfire protection programs using a choice experiment with three attributes: risk, loss, and cost. A phone-mail-phone survey was used to collect data from homeowners predominantly living in medium and high wildfire risk communities in Florida. We tested three hypotheses: (1) homeowner...

A simulation of probabilistic wildfire risk components for the continental United States

Science.gov (United States)

Mark A. Finney; Charles W. McHugh; Isaac C. Grenfell; Karin L. Riley; Karen C. Short

2011-01-01

This simulation research was conducted in order to develop a large-fire risk assessment system for the contiguous land area of the United States. The modeling system was applied to each of 134 Fire Planning Units (FPUs) to estimate burn probabilities and fire size distributions. To obtain stable estimates of these quantities, fire ignition and growth was simulated for...

Creation a Geo Big Data Outreach and Training Collaboratory for Wildfire Community

Science.gov (United States)

Altintas, I.; Sale, J.; Block, J.; Cowart, C.; Crawl, D.

2015-12-01

student internships. Students have worked closely with WIFIRE researchers on various projects including the development of statistical models of wildfire ignition probabilities for southern California, and the development of a smartphone app for crowd-sourced wildfire reporting through social networks such as Twitter and Facebook.

Predicted fates of ground-nesting bees in soil heated by wildfire: Thermal tolerances of life stages and a survey of nesting depths

Science.gov (United States)

James H. Cane; John L. Neff

2011-01-01

Periodic wildfire defines plant community composition and dynamics in many of the world's semi-arid biomes, whose climates and floras also favor wild bee diversity. Invasive flammable grasses, deforestation, historical fire suppression and human ignition are increasing fire frequency and intensifying its severity, as well as introducing fire to previously...

Appendix 2: Risk-based framework and risk case studies. Risk assessment for wildfire in the Western United States.

Science.gov (United States)

David L. Peterson; Jeremy S. Littell

2012-01-01

Wildfire is one of the two most significant disturbance agents (the other being insects) in forest ecosystems of the Western United States, and in a warmer climate, will drive changes in forest composition, structure, and function (Dale et al. 2001, McKenzie et al. 2004). Although wildfire is highly stochastic in space and time, sufficient data exist to establish clear...

Wildfire air pollution hazard during the 21st century

Directory of Open Access Journals (Sweden)

W. Knorr

2017-07-01

Full Text Available Wildfires pose a significant risk to human livelihoods and are a substantial health hazard due to emissions of toxic smoke. Previous studies have shown that climate change, increasing atmospheric CO2, and human demographic dynamics can lead to substantially altered wildfire risk in the future, with fire activity increasing in some regions and decreasing in others. The present study re-examines these results from the perspective of air pollution risk, focussing on emissions of airborne particulate matter (PM2. 5, combining an existing ensemble of simulations using a coupled fire–dynamic vegetation model with current observation-based estimates of wildfire emissions and simulations with a chemical transport model. Currently, wildfire PM2. 5 emissions exceed those from anthropogenic sources in large parts of the world. We further analyse two extreme sets of future wildfire emissions in a socio-economic, demographic climate change context and compare them to anthropogenic emission scenarios reflecting current and ambitious air pollution legislation. In most regions of the world, ambitious reductions of anthropogenic air pollutant emissions have the potential to limit mean annual pollutant PM2. 5 levels to comply with World Health Organization (WHO air quality guidelines for PM2. 5. Worst-case future wildfire emissions are not likely to interfere with these annual goals, largely due to fire seasonality, as well as a tendency of wildfire sources to be situated in areas of intermediate population density, as opposed to anthropogenic sources that tend to be highest at the highest population densities. However, during the high-fire season, we find many regions where future PM2. 5 pollution levels can reach dangerous levels even for a scenario of aggressive reduction of anthropogenic emissions.

Assessing the hydrologic response to wildfires in mountainous regions

Science.gov (United States)

Havel, Aaron; Tasdighi, Ali; Arabi, Mazdak

2018-04-01

This study aims to understand the hydrologic responses to wildfires in mountainous regions at various spatial scales. The Soil and Water Assessment Tool (SWAT) was used to evaluate the hydrologic responses of the upper Cache la Poudre Watershed in Colorado to the 2012 High Park and Hewlett wildfire events. A baseline SWAT model was established to simulate the hydrology of the study area between the years 2000 and 2014. A procedure involving land use and curve number updating was implemented to assess the effects of wildfires. Application of the proposed procedure provides the ability to simulate the hydrologic response to wildfires seamlessly through mimicking the dynamic of the changes due to wildfires. The wildfire effects on curve numbers were determined comparing the probability distribution of curve numbers after calibrating the model for pre- and post-wildfire conditions. Daily calibration and testing of the model produced very good results. No-wildfire and wildfire scenarios were created and compared to quantify changes in average annual total runoff volume, water budgets, and full streamflow statistics at different spatial scales. At the watershed scale, wildfire conditions showed little impact on the hydrologic responses. However, a runoff increase up to 75 % was observed between the scenarios in sub-watersheds with high burn intensity. Generally, higher surface runoff and decreased subsurface flow were observed under post-wildfire conditions. Flow duration curves developed for burned sub-watersheds using full streamflow statistics showed that less frequent streamflows become greater in magnitude. A linear regression model was developed to assess the relationship between percent burned area and runoff increase in Cache la Poudre Watershed. A strong (R2 > 0.8) and significant (p statistics through application of flow duration curves revealed that the wildfires had a higher effect on peak flows, which may increase the risk of flash floods in post-wildfire

A Mixed Logit Model of Homeowner Preferences for Wildfire Hazard Reduction

Science.gov (United States)

Thomas P. Holmes; John Loomis; Armando Gonzalez-Caban

2010-01-01

People living in the wildland-urban interface (WUI) are at greater risk of suffering major losses of property and life from wildfires. Over the past several decades the prevailing view has been that wildfire risk in rural areas was exogenous to the activities of homeowners. In response to catastrophic fires in the WUI over the past few years, recent approaches to fire...

Structure ignition assessment model (SIAM)\\t

Science.gov (United States)

Jack D. Cohen

1995-01-01

Major wildland/urban interface fire losses, principally residences, continue to occur. Although the problem is not new, the specific mechanisms are not well known on how structures ignite in association with wildland fires. In response to the need for a better understanding of wildland/urban interface ignition mechanisms and a method of assessing the ignition risk,...

Situating Hazard Vulnerability: People's Negotiations with Wildfire Environments in the U.S. Southwest

Science.gov (United States)

Collins, Timothy W.; Bolin, Bob

2009-09-01

This article is based on a multimethod study designed to clarify influences on wildfire hazard vulnerability in Arizona’s White Mountains, USA. Findings reveal that multiple factors operating across scales generate socially unequal wildfire risks. At the household scale, conflicting environmental values, reliance on fire insurance and firefighting institutions, a lack of place dependency, and social vulnerability (e.g., a lack of financial, physical, and/or legal capacity to reduce risks) were found to be important influences on wildfire risk. At the regional-scale, the shift from a resource extraction to environmental amenity-based economy has transformed ecological communities, produced unequal social distributions of risks and resources, and shaped people’s social and environmental interactions in everyday life. While working-class locals are more socially vulnerable than amenity migrants to wildfire hazards, they have also been more active in attempting to reduce risks in the aftermath of the disastrous 2002 Rodeo-Chediski fire. Social tensions between locals and amenity migrants temporarily dissolved immediately following the disaster, only to be exacerbated by the heightened perception of risk and the differential commitment to hazard mitigation displayed by these groups over a 2-year study period. Findings suggest that to enhance wildfire safety, environmental managers should acknowledge the environmental benefits associated with hazardous landscapes, the incentives created by risk management programs, and the specific constraints to action for relevant social groups in changing human-environmental context.

Outreach Programs, Peer Pressure, and Common Sense: What Motivates Homeowners to Mitigate Wildfire Risk?

Science.gov (United States)

McCaffrey, Sarah M.; Stidham, Melanie; Toman, Eric; Shindler, Bruce

2011-09-01

In recent years, altered forest conditions, climate change, and the increasing numbers of homes built in fire prone areas has meant that wildfires are affecting more people. An important part of minimizing the potential negative impacts of wildfire is engaging homeowners in mitigating the fire hazard on their land. It is therefore important to understand what makes homeowners more or less willing to take action. The research presented here comes from a study that interviewed a total of 198 homeowners in six communities in the western United States about the activities they had undertaken to mitigate their fire risk, the factors that contributed to their decisions, and their future intentions. The current paper reports on findings from the first half of the longitudinal study, after 3 years we will return to interview the current homeowner on the same properties to assess maintenance actions and facilitating and limiting factors. Overall we found a body of individuals who understand the fire risk, are taking numerous mitigation actions, and think that these actions have reduced their risk. These homeowners typically did not expect the government to do it for them: they wanted information about what to do and, in some cases, assistance with the work, but saw taking care of their property primarily as their responsibility. Responses also show that key information sources and motivating factors vary by location and that it is not inherently necessary to have relationships between community members to create defensible space.

Modeling anthropogenic and natural fire ignitions in an inner-alpine valley

Directory of Open Access Journals (Sweden)

G. Vacchiano

2018-03-01

Full Text Available Modeling and assessing the factors that drive forest fire ignitions is critical for fire prevention and sustainable ecosystem management. In southern Europe, the anthropogenic component of wildland fire ignitions is especially relevant. In the Alps, however, the role of fire as a component of disturbance regimes in forest and grassland ecosystems is poorly known. The aim of this work is to model the probability of fire ignition for an Alpine region in Italy using a regional wildfire archive (1995–2009 and MaxEnt modeling. We analyzed separately (i winter forest fires, (ii winter fires on grasslands and fallow land, and (iii summer fires. Predictors were related to morphology, climate, and land use; distance from infrastructures, number of farms, and number of grazing animals were used as proxies for the anthropogenic component. Collinearity among predictors was reduced by a principal component analysis. Regarding ignitions, 30 % occurred in agricultural areas and 24 % in forests. Ignitions peaked in the late winter–early spring. Negligence from agrosilvicultural activities was the main cause of ignition (64 %; lightning accounted for 9 % of causes across the study time frame, but increased from 6 to 10 % between the first and second period of analysis. Models for all groups of fire had a high goodness of fit (AUC 0.90–0.95. Temperature was proportional to the probability of ignition, and precipitation was inversely proportional. Proximity from infrastructures had an effect only on winter fires, while the density of grazing animals had a remarkably different effect on summer (positive correlation and winter (negative fires. Implications are discussed regarding climate change, fire regime changes, and silvicultural prevention. Such a spatially explicit approach allows us to carry out spatially targeted fire management strategies and may assist in developing better fire management plans.

Modeling anthropogenic and natural fire ignitions in an inner-alpine valley

Science.gov (United States)

Vacchiano, Giorgio; Foderi, Cristiano; Berretti, Roberta; Marchi, Enrico; Motta, Renzo

2018-03-01

Modeling and assessing the factors that drive forest fire ignitions is critical for fire prevention and sustainable ecosystem management. In southern Europe, the anthropogenic component of wildland fire ignitions is especially relevant. In the Alps, however, the role of fire as a component of disturbance regimes in forest and grassland ecosystems is poorly known. The aim of this work is to model the probability of fire ignition for an Alpine region in Italy using a regional wildfire archive (1995-2009) and MaxEnt modeling. We analyzed separately (i) winter forest fires, (ii) winter fires on grasslands and fallow land, and (iii) summer fires. Predictors were related to morphology, climate, and land use; distance from infrastructures, number of farms, and number of grazing animals were used as proxies for the anthropogenic component. Collinearity among predictors was reduced by a principal component analysis. Regarding ignitions, 30 % occurred in agricultural areas and 24 % in forests. Ignitions peaked in the late winter-early spring. Negligence from agrosilvicultural activities was the main cause of ignition (64 %); lightning accounted for 9 % of causes across the study time frame, but increased from 6 to 10 % between the first and second period of analysis. Models for all groups of fire had a high goodness of fit (AUC 0.90-0.95). Temperature was proportional to the probability of ignition, and precipitation was inversely proportional. Proximity from infrastructures had an effect only on winter fires, while the density of grazing animals had a remarkably different effect on summer (positive correlation) and winter (negative) fires. Implications are discussed regarding climate change, fire regime changes, and silvicultural prevention. Such a spatially explicit approach allows us to carry out spatially targeted fire management strategies and may assist in developing better fire management plans.

Evaluating alternative prescribed burning policies to reduce net economic damages from wildfire

Science.gov (United States)

D. Evan Mercer; Jeffrey P. Prestemon; David T. Butry; John M. Pye

2007-01-01

We estimate a wildfire risk model with a new measure of wildfire output, intensity-weighted risk and use it in Monte Carlo simulations to estimate welfare changes from alternative prescribed burning policies. Using Volusia County, Florida as a case study, an annual prescribed burning rate of 13% of all forest lands maximizes net welfare; ignoring the effects on...

Desertification and other ecological impacts produced by the historic Rodeo-Chediski Wildfire of 2000, Arizona, USA

Science.gov (United States)

Neary, D.; Ffolliott, P.; Stropki, C.

2009-04-01

The Rodeo-Chediski Wildfire - the largest in Arizona's history - damaged or destroyed ecosystem resources and disrupted ecosystem functioning in a largely mosaic pattern throughout the ponderosa pine (Pinus ponderosa) forests exposed to the burn. Impacts of this wildfire on tree overstories were studied on two watersheds in the area burned; one watershed burned by a high severity (stand-replacing) fire, while the other watershed burned by a low severity (stand-modifying) fire. The Rodeo-Chediski wildfire damaged or destroyed ecosystem resources and disrupted the ecological functioning on much of the 189,015 ha impacted by the burning. Intermingling chaparral shrub communities and pinyon-juniper woodlands at lower elevations and ponderosa pine forests at high elevations were located within the burned area. The wildfire was caused by two human ignitions that merged into one inferno. The Rodeo Fire was started by an arsonist on June 18, 2002, while the Chediski Fire was ignited as a signal fire by a stranded motorist on June 20th. The two fires merged on June 26, 2002, to become the Rodeo-Chediski Wildfire. The combined wildfires were contained on July 7th at a suppression (firefighting) cost of about €37.9 million (USA 50 million). However, the estimated costs associated with property losses; losses of ecosystem, anthropological, and cultural resources; and post-fire rehabilitation efforts increased the costs of the wildfire to over €114 million (USA 150 million). About one-half of the total area that was burned by the Rodeo-Chediski Wildfire experienced a high-severity fire, other areas burned at a low- to medium-severity fire, and still other areas were largely unburned according to a Burned Area Emergency Rehabilitation (BAER) report and fire severity map prepared shortly after containment of the wildfire. A mosaic of areas burned at varying fire severities within intermingling unburned areas resulted. Post-fire rehabilitation efforts, including establishment

The effect of personal experience on choice-based preferences for wildfire protection programs

Science.gov (United States)

Tom Holmes; Armando Gonzalez-Caban; John Loomis; Jose Sanchez

2013-01-01

In this paper, we investigate homeowner preferences and willingness to pay for wildfire protection programs using a choice experiment with three attributes: risk, loss and cost. Preference heterogeneity among survey respondents was examined using three econometric models and risk preferences were evaluated by comparing willingness to pay for wildfire protection...

Characterizing Early Succession Following Wildfires at Different Severities in Boreal Bog and Fen Peatlands

Science.gov (United States)

Ernst, E. J.; Bourgeau-Chavez, L. L.; Kane, E. S.; Wagenbrenner, J. W.; Endres, S.

2016-12-01

The Arctic-boreal region is experiencing changes in climate, trending toward warmer summers, resulting in a greater occurrence of wildfires with longer burning periods and higher intensities. Drought-like conditions have dried surface fuels, leading to a higher probability of ignition, even in lowland peatlands. Previous work has been done to characterize post-fire succession rates in Arctic-boreal upland sites, but much less is known of fire effects and early successional dynamics in lowlands. Wildland fires are the number one disturbance in Canada's Northwest Territories (NWT), which characteristically burn at high intensities with large flame fronts, and result in some of the biggest wildfires in the world. Areas surrounding the Great Slave Lake, NWT—including parts of the Taiga Plains, Taiga Shield, and Boreal Plains ecozones—experienced exceptional wildfire activity in 2014 and 2015. We characterized burn severity of the bog and fen peat surface and canopy layers at several burned sites. To determine if the severe ground or crown wildfires were stand-replacing events, we characterized post-fire vegetation in peatlands in 2015 and 2016 based on seedling regeneration. We stratified sites according to estimated water residence times across the three ecozones and made comparisons between data collected at the same sites across years. This work adds much needed context for post-fire succession in boreal peatland ecosystems, as the susceptibility of these systems to burning will continue to increase with a warming climate.

Mitigation of emissions from wildfires in Australia: potential for use of managed prescribed fire in eucalypt dominated vegetation, present and future. (Invited)

Science.gov (United States)

Bradstock, R.; Price, O.; Williams, D.; Hutley, L.

2010-12-01

Species of Eucalyptus and other closely related genera dominate woodlands and forests in the moist regions of tropical and temperate Australia. Respectively, these savanna woodlands and open forests are highly fire prone, though fire regimes are fundamentally different due to inherent influences of weather, fuels, ignitions and terrain. Fuel reduction via prescribed burning is commonly used in both savanna woodlands and temperate, open forests with the intention of reducing the incidence, extent and intensity of wildfires and subsequent risk to human and environmental assets. The prospect of mitigation of greenhouse gas emissions from wildfires provides further impetus for extensive use of prescribed fire. This potential is dependent on a number of key factors, namely the efficacy of this fuel reduction technique and the relative difference in the intensity of prescribed fires and wildfires. We present a conceptual model of the potential for prescribed fire to mitigate emissions based on these key factors. Prescribed burning requires an outlay of emissions in return for a saving through a reduction in area burned and intensity of subsequent wildfires. If the reduction in area burned by wildfires, achieved through prescribed burning, is relatively small then the reduction in intensity of wildfires must be relatively large in order to achieve a net reduction in emissions. This is not the case if prescribed burning has a strong effect in reducing the size of wildfires. Contemporary data indicate that the effect of prescribed burning in reducing area burned by wildfires is high in savanna woodlands but relatively low in forests. Corresponding potential for mitigation of emissions is therefore high and low respectively. We tested this prediction for forests by estimating fire intensity and fuel consumption using a range of fuel accumulation models for south eastern Australian forests. The results indicate that at the level of effectiveness of prescribed fire achieved

Restoring forest structure and process stabilizes forest carbon in wildfire-prone southwestern ponderosa pine forests.

Science.gov (United States)

Hurteau, Matthew D; Liang, Shuang; Martin, Katherine L; North, Malcolm P; Koch, George W; Hungate, Bruce A

2016-03-01

Changing climate and a legacy of fire-exclusion have increased the probability of high-severity wildfire, leading to an increased risk of forest carbon loss in ponderosa pine forests in the southwestern USA. Efforts to reduce high-severity fire risk through forest thinning and prescribed burning require both the removal and emission of carbon from these forests, and any potential carbon benefits from treatment may depend on the occurrence of wildfire. We sought to determine how forest treatments alter the effects of stochastic wildfire events on the forest carbon balance. We modeled three treatments (control, thin-only, and thin and burn) with and without the occurrence of wildfire. We evaluated how two different probabilities of wildfire occurrence, 1% and 2% per year, might alter the carbon balance of treatments. In the absence of wildfire, we found that thinning and burning treatments initially reduced total ecosystem carbon (TEC) and increased net ecosystem carbon balance (NECB). In the presence of wildfire, the thin and burn treatment TEC surpassed that of the control in year 40 at 2%/yr wildfire probability, and in year 51 at 1%/yr wildfire probability. NECB in the presence of wildfire showed a similar response to the no-wildfire scenarios: both thin-only and thin and burn treatments increased the C sink. Treatments increased TEC by reducing both mean wildfire severity and its variability. While the carbon balance of treatments may differ in more productive forest types, the carbon balance benefits from restoring forest structure and fire in southwestern ponderosa pine forests are clear.

Science You Can Use Bulletin: Fire on the mountain: What motivates homeowners to reduce their wildfire risk?

Science.gov (United States)

Sue Miller; Patty Champ; Hannah Brenkert-Smith

2013-01-01

New home building in the wildland-urban interface (WUI) continues unabated, despite the high financial and human costs of fighting fires in these areas. The goal of this research is to understand, through surveys and expert assessments, the attitudes and perceptions of WUI homeowners as they relate to taking action to reduce wildfire risk on their property. It also...

National Ignition Facility risk management plan, rev. 1

International Nuclear Information System (INIS)

Brereton, S J; Lane, M A

1998-01-01

The initial release of the National Ignition Facility (AUF) Risk Management Plan (LLNL, 1997a) was prepared in accordance with the DOE Life Cycle Asset Management Good Practice Guide (DOE, 1996a) and supported Critical Decision 3 (CD3), Approval to Initiate Construction (DOE, 1997a). The objectives of the plan were to: (1) Identify the risks to the completion of the Project in terms of meeting technical and regulatory requirements, cost, and schedule. (2) Assess the risks in terms of likelihood of occurrence and their impact potential relative to technical performance, ES and H (environmental, safety and health), costs, and schedule. (3) Address suitable risk mitigation measures for each identified risk. This revision of the Risk Management Plan considers project risks and vulnerabilities after CD3 (DOE, 1997a) was approved by the Secretary of Energy. During the one-year period since the initial release, the vulnerabilities of greatest concern have been the litigation of the Programmatic Environmental Impact Statement (PEIS) (DOE, 1996b) by a group of environmental organizations led by the Natural Resources Defense Council; the finding and successful clean-up of polychlorinated biphenyl (PCB)-filled electrical capacitors at the NIF site excavation; the FY98 congressional budget authorization and request for the FY99 budget authorization; funding for Inertial Confinement Fusion (ICF)/NIF programmatic activities (including French and other sources of funding); and finally, progress in the core science and technology, and optics program that form the basis for the NIF design

The potential of satellite data to study individual wildfire events

Science.gov (United States)

Benali, Akli; López-Saldana, Gerardo; Russo, Ana; Sá, Ana C. L.; Pinto, Renata M. S.; Nikos, Koutsias; Owen, Price; Pereira, Jose M. C.

2014-05-01

Large wildfires have important social, economic and environmental impacts. In order to minimize their impacts, understand their main drivers and study their dynamics, different approaches have been used. The reconstruction of individual wildfire events is usually done by collection of field data, interviews and by implementing fire spread simulations. All these methods have clear limitations in terms of spatial and temporal coverage, accuracy, subjectivity of the collected information and lack of objective independent validation information. In this sense, remote sensing is a promising tool with the potential to provide relevant information for stakeholders and the research community, by complementing or filling gaps in existing information and providing independent accurate quantitative information. In this work we show the potential of satellite data to provide relevant information regarding the dynamics of individual large wildfire events, filling an important gap in wildfire research. We show how MODIS active-fire data, acquired up to four times per day, and satellite-derived burnt perimeters can be combined to extract relevant information wildfire events by describing the methods involved and presenting results for four regions of the world: Portugal, Greece, SE Australia and California. The information that can be retrieved encompasses the start and end date of a wildfire event and its ignition area. We perform an evaluation of the information retrieved by comparing the satellite-derived parameters with national databases, highlighting the strengths and weaknesses of both and showing how the former can complement the latter leading to more complete and accurate datasets. We also show how the spatio-temporal distribution of wildfire spread dynamics can be reconstructed using satellite-derived active-fires and how relevant descriptors can be extracted. Applying graph theory to satellite active-fire data, we define the major fire spread paths that yield

Wildfire and Spatial Patterns in Forests in Northwestern Mexico: The United States Wishes It Had Similar Fire Problems

Directory of Open Access Journals (Sweden)

Scott L. Stephens

2008-12-01

Full Text Available Knowledge of the ecological effect of wildfire is important to resource managers, especially from forests in which past anthropogenic influences, e.g., fire suppression and timber harvesting, have been limited. Changes to forest structure and regeneration patterns were documented in a relatively unique old-growth Jeffrey pine-mixed conifer forest in northwestern Mexico after a July 2003 wildfire. This forested area has never been harvested and fire suppression did not begin until the 1970s. Fire effects were moderate especially considering that the wildfire occurred at the end of a severe, multi-year (1999-2003 drought. Shrub consumption was an important factor in tree mortality and the dominance of Jeffrey pine increased after fire. The Baja California wildfire enhanced or maintained a patchy forest structure; similar spatial heterogeneity should be included in US forest restoration plans. Most US forest restoration plans include thinning from below to separate tree crowns and attain a narrow range for residual basal area/ha. This essentially produces uniform forest conditions over broad areas that are in strong contrast to the resilient forests in northern Baja California. In addition to producing more spatial heterogeneity in restoration plans of forests that once experienced frequent, low-moderate intensity fire regimes, increased use of US wildfire management options such as wildland fire use as well as appropriate management responses to non-natural ignitions could also be implemented at broader spatial scales to increase the amount of burning in western US forests.

Fire spread estimation on forest wildfire using ensemble kalman filter

Science.gov (United States)

Syarifah, Wardatus; Apriliani, Erna

2018-04-01

Wildfire is one of the most frequent disasters in the world, for example forest wildfire, causing population of forest decrease. Forest wildfire, whether naturally occurring or prescribed, are potential risks for ecosystems and human settlements. These risks can be managed by monitoring the weather, prescribing fires to limit available fuel, and creating firebreaks. With computer simulations we can predict and explore how fires may spread. The model of fire spread on forest wildfire was established to determine the fire properties. The fire spread model is prepared based on the equation of the diffusion reaction model. There are many methods to estimate the spread of fire. The Kalman Filter Ensemble Method is a modified estimation method of the Kalman Filter algorithm that can be used to estimate linear and non-linear system models. In this research will apply Ensemble Kalman Filter (EnKF) method to estimate the spread of fire on forest wildfire. Before applying the EnKF method, the fire spread model will be discreted using finite difference method. At the end, the analysis obtained illustrated by numerical simulation using software. The simulation results show that the Ensemble Kalman Filter method is closer to the system model when the ensemble value is greater, while the covariance value of the system model and the smaller the measurement.

Land use planning and wildfire: development policies influence future probability of housing loss

Science.gov (United States)

Syphard, Alexandra D.; Massada, Avi Bar; Butsic, Van; Keeley, Jon E.

2013-01-01

Increasing numbers of homes are being destroyed by wildfire in the wildland-urban interface. With projections of climate change and housing growth potentially exacerbating the threat of wildfire to homes and property, effective fire-risk reduction alternatives are needed as part of a comprehensive fire management plan. Land use planning represents a shift in traditional thinking from trying to eliminate wildfires, or even increasing resilience to them, toward avoiding exposure to them through the informed placement of new residential structures. For land use planning to be effective, it needs to be based on solid understanding of where and how to locate and arrange new homes. We simulated three scenarios of future residential development and projected landscape-level wildfire risk to residential structures in a rapidly urbanizing, fire-prone region in southern California. We based all future development on an econometric subdivision model, but we varied the emphasis of subdivision decision-making based on three broad and common growth types: infill, expansion, and leapfrog. Simulation results showed that decision-making based on these growth types, when applied locally for subdivision of individual parcels, produced substantial landscape-level differences in pattern, location, and extent of development. These differences in development, in turn, affected the area and proportion of structures at risk from burning in wildfires. Scenarios with lower housing density and larger numbers of small, isolated clusters of development, i.e., resulting from leapfrog development, were generally predicted to have the highest predicted fire risk to the largest proportion of structures in the study area, and infill development was predicted to have the lowest risk. These results suggest that land use planning should be considered an important component to fire risk management and that consistently applied policies based on residential pattern may provide substantial benefits for

Optimizing Precipitation Thresholds for Best Correlation Between Dry Lightning and Wildfires

Science.gov (United States)

Vant-Hull, Brian; Thompson, Tollisha; Koshak, William

2018-03-01

This work examines how to adjust the definition of "dry lightning" in order to optimize the correlation between dry lightning flash count and the climatology of large (>400 km2) lightning-ignited wildfires over the contiguous United States (CONUS). The National Lightning Detection Network™ and National Centers for Environmental Prediction Stage IV radar-based, gauge-adjusted precipitation data are used to form climatic data sets. For a 13 year analysis period over CONUS, a correlation of 0.88 is found between annual totals of wildfires and dry lightning. This optimal correlation is found by defining dry lightning as follows: on a 0.1° hourly grid, a precipitation threshold of no more than 0.3 mm may accumulate during any hour over a period of 3-4 days preceding the flash. Regional optimized definitions vary. When annual totals are analyzed as done here, no clear advantage is found by weighting positive polarity cloud-to-ground (+CG) lightning differently than -CG lightning. The high variability of dry lightning relative to the precipitation and lightning from which it is derived suggests it would be an independent and useful climate indicator.

Examining heterogeneity and wildfire management expenditures using spatially and temporally descriptive data

Science.gov (United States)

Michael S. Hand; Matthew P. Thompson; Dave Calkin

2016-01-01

Increasing costs of wildfire management have highlighted the need to better understand suppression expenditures and potential tradeoffs of land management activities that may affect fire risks. Spatially and temporally descriptive data is used to develop a model of wildfire suppression expenditures, providing new insights into the role of spatial and temporal...

Hydrologic responses to restored wildfire regimes revealed by soil moisture-vegetation relationships

Science.gov (United States)

Boisramé, Gabrielle; Thompson, Sally; Stephens, Scott

2018-02-01

Many forested mountain watersheds worldwide evolved with frequent fire, which Twentieth Century fire suppression activities eliminated, resulting in unnaturally dense forests with high water demand. Restoration of pre-suppression forest composition and structure through a variety of management activities could improve forest resilience and water yields. This study explores the potential for "managed wildfire", whereby naturally ignited fires are allowed to burn, to alter the water balance. Interest in this type of managed wildfire is increasing, yet its long-term effects on water balance are uncertain. We use soil moisture as a spatially-distributed hydrologic indicator to assess the influence of vegetation, fire history and landscape position on water availability in the Illilouette Creek Basin in Yosemite National Park. Over 6000 manual surface soil moisture measurements were made over a period of three years, and supplemented with continuous soil moisture measurements over the top 1m of soil in three sites. Random forest and linear mixed effects models showed a dominant effect of vegetation type and history of vegetation change on measured soil moisture. Contemporary and historical vegetation maps were used to upscale the soil moisture observations to the basin and infer soil moisture under fire-suppressed conditions. Little change in basin-averaged soil moisture was inferred due to managed wildfire, but the results indicated that large localized increases in soil moisture had occurred, which could have important impacts on local ecology or downstream flows.

Wildfire Activity Across the Triassic-Jurassic Boundary in the Polish Basin: Evidence from New Fossil Charcoal & Carbon-isotope Data

Science.gov (United States)

Pointer, R.; Belcher, C.; Hesselbo, S. P.; Hodbod, M.; Pieńkowski, G.

2017-12-01

New fossil charcoal abundance and carbon-isotope data from two sedimentary cores provide new evidence of extreme environmental conditions in the Polish Basin during the Latest Triassic to Earliest Jurassic. Sedimentary cores from the Polish Basin provide an excellent record of terrestrial environmental conditions across the Triassic-Jurassic Boundary, a time of climatic extremes. Previous work has shown that the marine realm was affected by a large perturbation to the carbon cycle across the Triassic-Jurassic Boundary (manifested by large negative and positive carbon-isotope excursions) and limited records of charcoal abundance and organic geochemistry have indicated important changes in fire regime in the coeval ecosystems. Here we present two new carbon-isotope records generated from fossil plant matter across the Triassic-Jurassic boundary, and present new charcoal records. The charcoal abundance data confirm that there was variation in wildfire activity during the Late Triassic-Early Jurassic in the Polish Basin. Peaks in the number of fossil charcoal fragments present occur in both sedimentary cores, and increases in fossil charcoal abundance are linked to wildfires, signalling a short-lived rise in wildfire activity. Fossil charcoal abundance does not appear to be fully controlled by total organic matter content, depositional environment or bioturbation. We argue that increased wildfire activity is likely caused by an increase in ignition of plant material as a result of an elevated number of lightning strikes. Global warming (caused by a massive input of carbon into the atmosphere, as indicated by carbon-isotope data) can increase storm activity, leading to increased numbers of lightning strikes. Previous Triassic-Jurassic Boundary wildfire studies have found fossil charcoal abundance peaks at other northern hemisphere sites (Denmark & Greenland), and concluded that they represent increases in wildfire activity in the earliest Jurassic. Our new charcoal and

Airborne Measurements and Emission Estimates of Greenhouse Gases and Other Trace Constituents From the 2013 California Yosemite Rim Wildfire

Science.gov (United States)

Yates, E. L.; Iraci, L. T.; Singh, H. B.; Tanaka, T.; Roby, M. C.; Hamill, P.; Clements, C. B.; Lareau, N.; Contezac, J.; Blake, D. R.;

Economics of wildfire management: The development and application of suppression expenditure models

Science.gov (United States)

Michael S. Hand; Krista M. Gebert; Jingjing Liang; David E. Calkin; Matthew P. Thompson; Mo Zhou

2014-01-01

In the United States, increased wildland fire activity over the last 15 years has resulted in increased pressure to balance the cost, benefits, and risks of wildfire management. Amid increased public scrutiny and a highly variable wildland fire environment, a substantial body of research has developed to study factors affecting the cost-effectiveness of wildfire...

Wildfire smoke exposure and human health: Significant gaps in research for a growing public health issue.

Science.gov (United States)

Black, Carolyn; Tesfaigzi, Yohannes; Bassein, Jed A; Miller, Lisa A

2017-10-01

Understanding the effect of wildfire smoke exposure on human health represents a unique interdisciplinary challenge to the scientific community. Population health studies indicate that wildfire smoke is a risk to human health and increases the healthcare burden of smoke-impacted areas. However, wildfire smoke composition is complex and dynamic, making characterization and modeling difficult. Furthermore, current efforts to study the effect of wildfire smoke are limited by availability of air quality measures and inconsistent air quality reporting among researchers. To help address these issues, we conducted a substantive review of wildfire smoke effects on population health, wildfire smoke exposure in occupational health, and experimental wood smoke exposure. Our goal was to evaluate the current literature on wildfire smoke and highlight important gaps in research. In particular we emphasize long-term health effects of wildfire smoke, recovery following wildfire smoke exposure, and health consequences of exposure in children. Copyright © 2017 Elsevier B.V. All rights reserved.

The Human and Physical Determinants of Wildfires and Burnt Areas in Israel

Science.gov (United States)

Levin, Noam; Tessler, Naama; Smith, Andrew; McAlpine, Clive

2016-09-01

Wildfires are expected to increase in Mediterranean landscapes as a result of climate change and changes in land-use practices. In order to advance our understanding of human and physical factors shaping spatial patterns of wildfires in the region, we compared two independently generated datasets of wildfires for Israel that cover approximately the same study period. We generated a site-based dataset containing the location of 10,879 wildfires (1991-2011), and compared it to a dataset of burnt areas derived from MODIS imagery (2000-2011). We hypothesized that the physical and human factors explaining the spatial distribution of burnt areas derived from remote sensing (mostly large fires, >100 ha) will differ from those explaining site-based wildfires recorded by national agencies (mostly small fires, human activities, improving the management of forest areas and raising public awareness to fire risk are key considerations in reducing fire danger.

An early warning system to forecast the close of the spring burning window from satellite-observed greenness.

Science.gov (United States)

Pickell, Paul D; Coops, Nicholas C; Ferster, Colin J; Bater, Christopher W; Blouin, Karen D; Flannigan, Mike D; Zhang, Jinkai

2017-10-27

Spring represents the peak of human-caused wildfire events in populated boreal forests, resulting in catastrophic loss of property and human life. Human-caused wildfire risk is anticipated to increase in northern forests as fuels become drier, on average, under warming climate scenarios and as population density increases within formerly remote regions. We investigated springtime human-caused wildfire risk derived from satellite-observed vegetation greenness in the early part of the growing season, a period of increased ignition and wildfire spread potential from snow melt to vegetation green-up with the aim of developing an early warning wildfire risk system. The initial system was developed for 392,856 km 2 of forested lands with satellite observations available prior to the start of the official wildfire season and predicted peak human-caused wildfire activity with 10-day accuracy for 76% of wildfire-protected lands by March 22. The early warning system could have significant utility as a cost-effective solution for wildfire managers to prioritize the deployment of wildfire protection resources in wildfire-prone landscapes across boreal-dominated ecosystems of North America, Europe, and Russia using open access Earth observations.

Outreach programs, peer pressure, and common sense: What motivates homeowners to mitigate wildfire risk?

Science.gov (United States)

Sarah M. McCaffrey; Melanie Stidham; Eric Toman; Bruce. Shindler

2011-01-01

In recent years, altered forest conditions, climate change, and the increasing numbers of homes built in fire prone areas has meant that wildfires are affecting more people. An important part of minimizing the potential negative impacts of wildfire is engaging homeowners in mitigating the fire hazard on their land. It is therefore important to understand what makes...

Fusion ignition via a magnetically-assisted fast ignition approach

OpenAIRE

Wang, W. -M.; Gibbon, P.; Sheng, Z. -M.; Li, Y. T.; Zhang, J.

2016-01-01

Significant progress has been made towards laser-driven fusion ignition via different schemes, including direct and indirect central ignition, fast ignition, shock ignition, and impact ignition schemes. However, to reach ignition conditions, there are still various technical and physical challenges to be solved for all these schemes. Here, our multi-dimensional integrated simulation shows that the fast-ignition conditions could be achieved when two 2.8 petawatt heating laser pulses counter-pr...

Assessing wildfire occurrence probability in Pinus pinaster Ait. stands in Portugal

Energy Technology Data Exchange (ETDEWEB)

Marques, S.; Garcia-Gonzalo, J.; Botequim, B.; Ricardo, A.; Borges, J. G.; Tome, M.; Oliveira, M. M.

2012-11-01

Maritime pine (Pinus pinaster Ait.) is an important conifer from the western Mediterranean Basin extending over 22% of the forest area in Portugal. In the last three decades nearly 4% of Maritime pine area has been burned by wildfires. Yet no wildfire occurrence probability models are available and forest and fire management planning activities are thus carried out mostly independently of each other. This paper presents research to address this gap. Specifically, it presents a model to assess wildfire occurrence probability in regular and pure Maritime pine stands in Portugal. Emphasis was in developing a model based on easily available inventory data so that it might be useful to forest managers. For that purpose, data from the last two Portuguese National Forest Inventories (NFI) and data from wildfire perimeters in the years from 1998 to 2004 and from 2006 to 2007 were used. A binary logistic regression model was build using biometrics data from the NFI. Biometric data included indicators that might be changed by operations prescribed in forest planning. Results showed that the probability of wildfire occurrence in a stand increases in stand located at steeper slopes and with high shrubs load while it decreases with precipitation and with stand basal area. These results are instrumental for assessing the impact of forest management options on wildfire probability thus helping forest managers to reduce the risk of wildfires. (Author) 57 refs.

Combining ungrouped and grouped wildfire data to estimate fire risk

KAUST Repository

Hernandez-Magallanes, I.

2013-01-01

particular year. The probability model is based on the wildfire point process. Assuming a smooth intensity function, a locally weighted likelihood fit is used, which incorporates the group effect. A logit model is used under the assumption of the existence

Just blowing smoke? Residents’ social construction of communication about wildfire

Science.gov (United States)

Travis Paveglio; Matthew S. Carroll; James D. Absher; Todd. Norton

2009-01-01

This study uses social constructionism as a basis for understanding the effectiveness of communication about wildfire risk between agency officials and wildland-urban interface (WUI) residents. Risk communication literature demonstrates a welldocumented difference in the way land managers and stakeholders conceptualize risk. This is especially true of fire because...

Ignition and fusion burn in fast ignition scheme

International Nuclear Information System (INIS)

Takabe, Hideaki

1998-01-01

The target physics of fast ignition is briefly reviewed by focusing on the ignition and fusion burn in the off-center ignition scheme. By the use of a two dimensional hydrodynamic code with an alpha heating process, the ignition condition is studied. It is shown that the ignition condition of the off-center ignition scheme coincides with that of the the central isochoric model. After the ignition, a nuclear burning wave is seen to burn the cold main fuel with a velocity of 2 - 3 x 10 8 cm/s. The spark energy required for the off-center ignition is 2 - 3 kJ or 10 - 15 kJ for the core density of 400 g/cm 3 or 200 g/cm 3 , respectively. It is demonstrated that a core gain of more than 2,000 is possible for a core energy of 100 kJ with a hot spark energy of 13 kJ. The requirement for the ignition region's heating time is also discussed by modeling a heating source in the 2-D code. (author)

Contribution of human, climate and biophysical drivers to the spatial distribution of wildfires in a French Mediterranean area: where do wildfires start and spread?

Science.gov (United States)

Ruffault, Julien; Mouillot, Florent; Moebius, Flavia

2013-04-01

Understanding the contribution of biophysical and human drivers to the spatial distribution of fires at regional scale has many ecological and economical implications in a context of on-going global changes. However these fire drivers often interact in complex ways, such that disentangling and assessing the relative contribution of human vs. biophysical factors remains a major challenge. Indeed, the identification of biophysical conditions that promote fires are confused by the inherent stochasticity in fire occurrences and fire spread on the one hand and, by the influence of human factors -through both fire ignition and suppression - on the other. Moreover, different factors may drive fire ignition and fire spread, in such a way that the areas with the highest density of ignitions may not coincide with those where large fires occur. In the present study, we investigated the drivers of fires ignition and spread in a Mediterranean area of southern France. We used a 17 years fire database (the PROMETHEE database from 1989-2006) combined with a set of 8 explanatory variables describing the spatial pattern in ignitions, vegetation and fire weather. We first isolated the weather conditions affecting the fire occurrence and their spread using a statistical model of the weather/fuel water status for each fire event.. The results of these statistical models were used to map the fire weather in terms of average number of days with suitable conditions for burning. Then, we used Boosted regression trees (BRT) models to assess the relative importance of the different variables on the distribution of wildfire with different sizes and to assess the relationship between each variables and fire occurrence and spread probabilities. We found that human activities explained up to 50 % of the spatial distribution of fire ignitions (SDI). The distribution of large fire was chiefly explained by fuel characteristics (about 40%). Surprisingly, the weather indices explained only 20 % of

Ignition probability of fine dead surface fuels of native Patagonian forests or Argentina

Directory of Open Access Journals (Sweden)

Lucas O. Bianchi

2014-04-01

Full Text Available Aim of study: The Canadian Forest Fire Weather Index (FWI is being implemented all over the world. This index is being adapted to the Argentinean ecosystems since the year 2000. With the objective of calibrating the Fine Fuel Moisture Code (FFMC of the FWI system to Patagonian forests, we studied the relationship between ignition probability and fine dead surface fuel moisture content (MC as an indicator of potential fire ignition.Area of study: The study area is located in northwestern Patagonia, Argentina, and comprised two main forest types (cypress and ñire grown under a Mediterranean climate, with a dry summer and precipitations during winter and autumn (~500-800 mm per year.Material and Methods: We conducted lab ignition tests fires to determine the threshold of fine dead fuel ignition at different MC levels. Moisture content of dead fine surface fuels in the field was measured every 10-15 days from November to March for three seasons. We calculated the FFMC during these seasons and correlated it with the measured MC by applying a logistic regression model. We combined the results of the ignition tests and of the regressions to suggest FFMC categories for estimating fire danger in Patagonian forests.Main results: The ignition threshold occurred at MC values of 21.5 and 25.0% for cypress and ñire sites, respectively. The MC measured varied from 7.3 to 129.6%, and the calculated FFMC varied between 13.4 and 92.6. Highly significant regressions resulted when FFMC was related to MC. The ignition threshold corresponded to a FFMC=85. We proposed to divide the FFMC scale in three fire danger categories: Low (FFMC≤85, High (8589.Research highlights: Our results provide a useful tool for predicting fire danger in these ecosystems, and are a contribution to the development of the Argentinean Fire Danger Rating and a reference for similar studies in other countries where the FWI is being implemented

Experimental determination of self-heating and self-ignition risks associated with the dusts of agricultural materials commonly stored in silos.

Science.gov (United States)

Ramírez, Alvaro; García-Torrent, Javier; Tascón, Alberto

2010-03-15

Agricultural products stored in silos, and their dusts, can undergo oxidation and self-heating, increasing the risk of self-ignition and therefore of fires and explosions. The aim of the present work was to determine the thermal susceptibility (as reflected by the Maciejasz index, the temperature of the emission of flammable volatile substances and the combined information provided by the apparent activation energy and the oxidation temperature) of icing sugar, bread-making flour, maize, wheat, barley, alfalfa, and soybean dusts, using experimental methods for the characterisation of different types of coal (no standardised procedure exists for characterising the thermal susceptibility of either coal or agricultural products). In addition, the thermal stability of wheat, i.e., the risk of self-ignition determined as a function of sample volume, ignition temperature and storage time, was determined using the methods outlined in standard EN 15188:2007. The advantages and drawbacks of the different methods used are discussed. (c) 2009 Elsevier B.V. All rights reserved.

Multiple UAV Cooperation for Wildfire Monitoring

Science.gov (United States)

Lin, Zhongjie

Wildfires have been a major factor in the development and management of the world's forest. An accurate assessment of wildfire status is imperative for fire management. This thesis is dedicated to the topic of utilizing multiple unmanned aerial vehicles (UAVs) to cooperatively monitor a large-scale wildfire. This is achieved through wildfire spreading situation estimation based on on-line measurements and wise cooperation strategy to ensure efficiency. First, based on the understanding of the physical characteristics of the wildfire propagation behavior, a wildfire model and a Kalman filter-based method are proposed to estimate the wildfire rate of spread and the fire front contour profile. With the enormous on-line measurements from on-board sensors of UAVs, the proposed method allows a wildfire monitoring mission to benefit from on-line information updating, increased flexibility, and accurate estimation. An independent wildfire simulator is utilized to verify the effectiveness of the proposed method. Second, based on the filter analysis, wildfire spreading situation and vehicle dynamics, the influence of different cooperation strategies of UAVs to the overall mission performance is studied. The multi-UAV cooperation problem is formulated in a distributed network. A consensus-based method is proposed to help address the problem. The optimal cooperation strategy of UAVs is obtained through mathematical analysis. The derived optimal cooperation strategy is then verified in an independent fire simulation environment to verify its effectiveness.

Application of wildfire risk assessment results to wildfire response planning in the southern Sierra Nevada, California, USA

Science.gov (United States)

Matthew P. Thompson; Phil Bowden; April Brough; Joe H. Scott; Julie Gilbertson-Day; Alan Taylor; Jennifer Anderson; Jessica Haas

2016-01-01

How wildfires are managed is a key determinant of long-term socioecological resiliency and the ability to live with fire. Safe and effective response to fire requires effective pre-fire planning, which is the main focus of this paper. We review general principles of effective federal fire management planning in the U.S., and introduce a framework for incident...

Adapt to more wildfire in western North American forests as climate changes.

Science.gov (United States)

Schoennagel, Tania; Balch, Jennifer K; Brenkert-Smith, Hannah; Dennison, Philip E; Harvey, Brian J; Krawchuk, Meg A; Mietkiewicz, Nathan; Morgan, Penelope; Moritz, Max A; Rasker, Ray; Turner, Monica G; Whitlock, Cathy

2017-05-02

Wildfires across western North America have increased in number and size over the past three decades, and this trend will continue in response to further warming. As a consequence, the wildland-urban interface is projected to experience substantially higher risk of climate-driven fires in the coming decades. Although many plants, animals, and ecosystem services benefit from fire, it is unknown how ecosystems will respond to increased burning and warming. Policy and management have focused primarily on specified resilience approaches aimed at resistance to wildfire and restoration of areas burned by wildfire through fire suppression and fuels management. These strategies are inadequate to address a new era of western wildfires. In contrast, policies that promote adaptive resilience to wildfire, by which people and ecosystems adjust and reorganize in response to changing fire regimes to reduce future vulnerability, are needed. Key aspects of an adaptive resilience approach are ( i ) recognizing that fuels reduction cannot alter regional wildfire trends; ( ii ) targeting fuels reduction to increase adaptation by some ecosystems and residential communities to more frequent fire; ( iii ) actively managing more wild and prescribed fires with a range of severities; and ( iv ) incentivizing and planning residential development to withstand inevitable wildfire. These strategies represent a shift in policy and management from restoring ecosystems based on historical baselines to adapting to changing fire regimes and from unsustainable defense of the wildland-urban interface to developing fire-adapted communities. We propose an approach that accepts wildfire as an inevitable catalyst of change and that promotes adaptive responses by ecosystems and residential communities to more warming and wildfire.

Wildfire spread, hazard and exposure metric raster grids for central Catalonia

Directory of Open Access Journals (Sweden)

Fermín J. Alcasena

2018-04-01

Full Text Available We provide 40 m resolution wildfire spread, hazard and exposure metric raster grids for the 0.13 million ha fire-prone Bages County in central Catalonia (northeastern Spain corresponding to node influence grid (NIG, crown fraction burned (CFB and fire transmission to residential houses (TR. Fire spread and behavior data (NIG, CFB and fire perimeters were generated with fire simulation modeling considering wildfire season extreme fire weather conditions (97th percentile. Moreover, CFB was also generated for prescribed fire (Rx mild weather conditions. The TR smoothed grid was obtained with a geospatial analysis considering large fire perimeters and individual residential structures located within the study area. We made these raster grids available to assist in the optimization of wildfire risk management plans within the study area and to help mitigate potential losses from catastrophic events. Keywords: Catalonia, Wildfire exposure, Fire transmission, Crown fire activity, Prescribed fires

Synoptic patterns associated with wildfires caused by lightning in Castile and Leon, Spain

Directory of Open Access Journals (Sweden)

E. García-Ortega

2011-03-01

Full Text Available The Iberian Peninsula presents the highest number of wildfires in Europe. In the NW of Spain in particular, wildfires are the natural risk with the greatest economic impact in this region. Wildfires caused by lightning are closely related to the triggering of convective phenomena. The prediction of thunderstorms is a very complex task because these weather events have a local character and are highly dependent on mesoscale atmospheric conditions. The development of convective storms is directly linked to the existence of a synoptic environment favoring convection. The aim of this study is to classify the atmospheric patterns that provide favorable environments for the occurrence of wildfires caused by lightning in the region of Castile and Leon, Spain. The database used for the study contains 376 wildfire days from the period 1987–2006. NCEP data reanalysis has been used. The atmospheric fields used to characterise each day were: geopotential heights and temperatures at 500 hPa and 850 hPa, relative humidity and the horizontal wind at 850 hPa. A Principal Component Analysis in T-mode followed by a Cluster Analysis resulted in a classification of wildfire days into five clusters. The characteristics of these clusters were analysed and described, focusing particularly on the study of those wildfire days in which more than one wildfire was detected. In these cases the main feature observed was the intensification of the disturbance typical of the cluster to which the wildfire belongs.

Economics of wildfire management the development and application of suppression expenditure models

CERN Document Server

Hand, Michael S; Liang, Jingjing; Thompson, Matthew P

2014-01-01

In this age of climatic and financial uncertainty, it becomes increasingly important to balance the cost, benefits and risk of wildfire management. In the United States, increased wildland fire activity over the last 15 years has resulted in drastic damage and loss of life. An associated rapid increase in fire management costs has consumed higher portions of budgets of public entities involved in wildfire management, challenging their ability to fulfill other responsibilities. Increased public scrutiny highlights the need to improve wildland fire management for cost effectiveness. This book closely examines the development of basic wildfire suppression cost models for the United States and their application to a wide range of settings from informing incident decision making to programmatic review. The book also explores emerging trends in suppression costs and introduces new spatially explicit cost models to account for characteristics of the burned landscape. Finally, it discusses how emerging risk assessmen...

Measuring the effect of fuel treatments on forest carbon using landscape risk analysis

Directory of Open Access Journals (Sweden)

A. A. Ager

2010-12-01

Full Text Available Wildfire simulation modelling was used to examine whether fuel reduction treatments can potentially reduce future wildfire emissions and provide carbon benefits. In contrast to previous reports, the current study modelled landscape scale effects of fuel treatments on fire spread and intensity, and used a probabilistic framework to quantify wildfire effects on carbon pools to account for stochastic wildfire occurrence. The study area was a 68 474 ha watershed located on the Fremont-Winema National Forest in southeastern Oregon, USA. Fuel reduction treatments were simulated on 10% of the watershed (19% of federal forestland. We simulated 30 000 wildfires with random ignition locations under both treated and untreated landscapes to estimate the change in burn probability by flame length class resulting from the treatments. Carbon loss functions were then calculated with the Forest Vegetation Simulator for each stand in the study area to quantify change in carbon as a function of flame length. We then calculated the expected change in carbon from a random ignition and wildfire as the sum of the product of the carbon loss and the burn probabilities by flame length class. The expected carbon difference between the non-treatment and treatment scenarios was then calculated to quantify the effect of fuel treatments. Overall, the results show that the carbon loss from implementing fuel reduction treatments exceeded the expected carbon benefit associated with lowered burn probabilities and reduced fire severity on the treated landscape. Thus, fuel management activities resulted in an expected net loss of carbon immediately after treatment. However, the findings represent a point in time estimate (wildfire immediately after treatments, and a temporal analysis with a probabilistic framework used here is needed to model carbon dynamics over the life cycle of the fuel treatments. Of particular importance is the long-term balance between emissions from the

Measuring the effect of fuel treatments on forest carbon using landscape risk analysis

Science.gov (United States)

Ager, A. A.; Finney, M. A.; McMahan, A.; Cathcart, J.

2010-12-01

Wildfire simulation modelling was used to examine whether fuel reduction treatments can potentially reduce future wildfire emissions and provide carbon benefits. In contrast to previous reports, the current study modelled landscape scale effects of fuel treatments on fire spread and intensity, and used a probabilistic framework to quantify wildfire effects on carbon pools to account for stochastic wildfire occurrence. The study area was a 68 474 ha watershed located on the Fremont-Winema National Forest in southeastern Oregon, USA. Fuel reduction treatments were simulated on 10% of the watershed (19% of federal forestland). We simulated 30 000 wildfires with random ignition locations under both treated and untreated landscapes to estimate the change in burn probability by flame length class resulting from the treatments. Carbon loss functions were then calculated with the Forest Vegetation Simulator for each stand in the study area to quantify change in carbon as a function of flame length. We then calculated the expected change in carbon from a random ignition and wildfire as the sum of the product of the carbon loss and the burn probabilities by flame length class. The expected carbon difference between the non-treatment and treatment scenarios was then calculated to quantify the effect of fuel treatments. Overall, the results show that the carbon loss from implementing fuel reduction treatments exceeded the expected carbon benefit associated with lowered burn probabilities and reduced fire severity on the treated landscape. Thus, fuel management activities resulted in an expected net loss of carbon immediately after treatment. However, the findings represent a point in time estimate (wildfire immediately after treatments), and a temporal analysis with a probabilistic framework used here is needed to model carbon dynamics over the life cycle of the fuel treatments. Of particular importance is the long-term balance between emissions from the decay of dead trees

Simultaneous measurement of ignition energy and current signature for brush discharges

International Nuclear Information System (INIS)

Fast, Lars; Andersson, Birgitta; Smallwood, Jeremy; Holdstock, Paul; Paasi, Jaakko

2011-01-01

Accurate prediction of the probability of ignition arising from charged insulators is a crucial element of risk assessment in process industry. Incendiary brush discharges can occur when a large or grounded conductor approaches a charged insulator in the presence of a flammable atmosphere. This paper describes ignition tests based on an IEC standard method and simultaneously recorded temporal distribution of current released in the discharges, using a discharge probe integrated with the ignition probe. Ignition and non-ignition results are compared with peak discharge current and charge transferred in the discharge. No clear ignition threshold was found for either of these parameters. No major differences were found between igniting and non-igniting waveforms.

Particulate Air Pollution from Wildfires in the Western US under Climate Change.

Science.gov (United States)

Liu, Jia Coco; Mickley, Loretta J; Sulprizio, Melissa P; Dominici, Francesca; Yue, Xu; Ebisu, Keita; Anderson, Georgiana Brooke; Khan, Rafi F A; Bravo, Mercedes A; Bell, Michelle L

2016-10-01

Wildfire can impose a direct impact on human health under climate change. While the potential impacts of climate change on wildfires and resulting air pollution have been studied, it is not known who will be most affected by the growing threat of wildfires. Identifying communities that will be most affected will inform development of fire management strategies and disaster preparedness programs. We estimate levels of fine particulate matter (PM 2.5 ) directly attributable to wildfires in 561 western US counties during fire seasons for the present-day (2004-2009) and future (2046-2051), using a fire prediction model and GEOS-Chem, a 3-D global chemical transport model. Future estimates are obtained under a scenario of moderately increasing greenhouse gases by mid-century. We create a new term "Smoke Wave," defined as ≥2 consecutive days with high wildfire-specific PM 2.5 , to describe episodes of high air pollution from wildfires. We develop an interactive map to demonstrate the counties likely to suffer from future high wildfire pollution events. For 2004-2009, on days exceeding regulatory PM 2.5 standards, wildfires contributed an average of 71.3% of total PM 2.5 . Under future climate change, we estimate that more than 82 million individuals will experience a 57% and 31% increase in the frequency and intensity, respectively, of Smoke Waves. Northern California, Western Oregon and the Great Plains are likely to suffer the highest exposure to widlfire smoke in the future. Results point to the potential health impacts of increasing wildfire activity on large numbers of people in a warming climate and the need to establish or modify US wildfire management and evacuation programs in high-risk regions. The study also adds to the growing literature arguing that extreme events in a changing climate could have significant consequences for human health.

Empirical evidence for multi-scaled controls on wildfire size distributions in California

Science.gov (United States)

Povak, N.; Hessburg, P. F., Sr.; Salter, R. B.

2014-12-01

Ecological theory asserts that regional wildfire size distributions are examples of self-organized critical (SOC) systems. Controls on SOC event-size distributions by virtue are purely endogenous to the system and include the (1) frequency and pattern of ignitions, (2) distribution and size of prior fires, and (3) lagged successional patterns after fires. However, recent work has shown that the largest wildfires often result from extreme climatic events, and that patterns of vegetation and topography may help constrain local fire spread, calling into question the SOC model's simplicity. Using an atlas of >12,000 California wildfires (1950-2012) and maximum likelihood estimation (MLE), we fit four different power-law models and broken-stick regressions to fire-size distributions across 16 Bailey's ecoregions. Comparisons among empirical fire size distributions across ecoregions indicated that most ecoregion's fire-size distributions were significantly different, suggesting that broad-scale top-down controls differed among ecoregions. One-parameter power-law models consistently fit a middle range of fire sizes (~100 to 10000 ha) across most ecoregions, but did not fit to larger and smaller fire sizes. We fit the same four power-law models to patch size distributions of aspect, slope, and curvature topographies and found that the power-law models fit to a similar middle range of topography patch sizes. These results suggested that empirical evidence may exist for topographic controls on fire sizes. To test this, we used neutral landscape modeling techniques to determine if observed fire edges corresponded with aspect breaks more often than expected by random. We found significant differences between the empirical and neutral models for some ecoregions, particularly within the middle range of fire sizes. Our results, combined with other recent work, suggest that controls on ecoregional fire size distributions are multi-scaled and likely are not purely SOC. California

Target designs for energetics experiments on the National Ignition Facility

International Nuclear Information System (INIS)

Meezan, N B; Glenzer, S H; Suter, L J

2008-01-01

The goal of the first hohlraum energetics experiments on the National Ignition Facility (NIF) [G. H. Miller et al, Optical Eng. 43, 2841 (2004)] is to select the hohlraum design for the first ignition experiments. Sub-scale hohlraums heated by 96 of the 192 laser beams on the NIF are used to emulate the laser-plasma interaction behavior of ignition hohlraums. These 'plasma emulator' targets are 70% scale versions of the 1.05 MJ, 300 eV ignition hohlraum and have the same energy-density as the full-scale ignition designs. Radiation-hydrodynamics simulations show that the sub-scale target is a good emulator of plasma conditions inside the ignition hohlraum, reproducing density n e within 10% and temperature T e within 15% along a laser beam path. Linear backscatter gain analysis shows the backscatter risk to be comparable to that of the ignition target. A successful energetics campaign will allow the National Ignition Campaign to focus its efforts on optimizing ignition hohlraums with efficient laser coupling

High-Gain Shock Ignition on the National Ignition Facility

Science.gov (United States)

Perkins, L. J.; Lafortune, K.; Bailey, D.; Lambert, M.; MacKinnon, A.; Blackfield, D.; Comley, A.; Schurtz, G.; Ribeyre, X.; Lebel, E.; Casner, A.; Craxton, R. S.; Betti, R.; McKenty, P.; Anderson, K.; Theobald, W.; Schmitt, A.; Atzeni, S.; Schiavi, A.

2010-11-01

Shock ignition offers the possibility for a near-term test of high-gain ICF on the NIF at less than 1MJ drive energy and with day-1 laser hardware. We will summarize the status of target performance simulations, delineate the critical issues and describe the R&D program to be performed in order to test the potential of a shock-ignited target on NIF. In shock ignition, compressed fuel is separately ignited by a late-time laser-driven shock and, because capsule implosion velocities are significantly lower than those required for conventional hotpot ignition, simulations indicate that fusion energy gains of 60 may be achievable at laser energies around 0.5MJ. Like fast ignition, shock ignition offers high gain but requires only a single laser with less demanding timing and focusing requirements. Conventional symmetry and stability constraints apply, thus a key immediate step towards attempting shock ignition on NIF is to demonstrate adequacy of low-mode uniformity and shock symmetry under polar drive

Future respiratory hospital admissions from wildfire smoke under climate change in the Western US

Science.gov (United States)

Coco Liu, Jia; Mickley, Loretta J.; Sulprizio, Melissa P.; Yue, Xu; Peng, Roger D.; Dominici, Francesca; Bell, Michelle L.

2016-12-01

Background. Wildfires are anticipated to be more frequent and intense under climate change. As a result, wildfires may emit more air pollutants that can harm health in communities in the future. The health impacts of wildfire smoke under climate change are largely unknown. Methods. We linked projections of future levels of fine particulate matter (PM2.5) specifically from wildfire smoke under the A1B climate change scenario using the GEOS-Chem model for 2046-2051, present-day estimates of hospital admission impacts from wildfire smoke, and future population projections to estimate the change in respiratory hospital admissions for persons ≥65 years by county (n = 561) from wildfire PM2.5 under climate change in the Western US. Results. The increase in intense wildfire smoke days from climate change would result in an estimated 178 (95% confidence interval: 6.2, 361) additional respiratory hospital admissions in the Western US, accounting for estimated future increase in the elderly population. Climate change is estimated to impose an additional 4990 high-pollution smoke days. Central Colorado, Washington and southern California are estimated to experience the highest percentage increase in respiratory admissions from wildfire smoke under climate change. Conclusion. Although the increase in number of respiratory admissions from wildfire smoke seems modest, these results provide important scientific evidence of an often-ignored aspect of wildfire impact, and information on their anticipated spatial distribution. Wildfires can cause serious social burdens such as property damage and suppression cost, but can also raise health problems. The results provide information that can be incorporated into development of environmental and health policies in response to climate change. Climate change adaptation policies could incorporate scientific evidence on health risks from natural disasters such as wildfires.

Pulse heating and ignition for off-centre ignited targets

International Nuclear Information System (INIS)

Mahdy, A.I.; Takabe, H.; Mima, K.

1999-01-01

An off-centre ignition model has been used to study the ignition conditions for laser targets related to the fast ignition scheme. A 2-D hydrodynamic code has been used, including alpha particle heating. The main goal of the study is the possibility of obtaining a high gain ICF target with fast ignition. In order to determine the ignition conditions, samples with various compressed core densities having different spark density-radius product (i.e. areal density) values were selected. The study was carried out in the presence of an external heating source, with a constant heating rate. A dependence of the ignition conditions on the heating rate of the external pulse is demonstrated. For a given set of ignition conditions, our simulation showed that an 11 ps pulse with 17 kJ of injected energy into the spark area was required to achieve ignition for a compressed core with a density of 200 g/cm 3 and 0.5 g/cm 2 spark areal density. It is shown that the ignition conditions are highly dependent on the heating rate of the external pulse. (author)

UAS Developments Supporting Wildfire Observations

Science.gov (United States)

Ambrosia, V. G.; Dahlgren, R. P.; Watts, A.; Reynolds, K. W.; Ball, T.

2014-12-01

Wildfires are regularly occurring emergency events that threaten life, property, and natural resources in every U.S. State and many countries around the world. Despite projections that $1.8 billion will be spent by U.S. Federal agencies alone on wildfires in 2014, the decades-long trend of increasing fire size, severity, and cost is expected to continue. Furthermore, the enormous potential for UAS (and concomitant sensor systems) to serve as geospatial intelligence tools to improve the safety and effectiveness of fire management, and our ability to forecast fire and smoke movements, remains barely tapped. Although orbital sensor assets are can provide the geospatial extent of wildfires, generally those resources are limited in use due to their spatial and temporal resolution limitations. These two critical elements make orbital assets of limited utility for tactical, real-time wildfire management, or for continuous scientific analysis of the temporal dynamics related to fire energy release rates and plume concentrations that vary significantly thru a fire's progression. Large UAS platforms and sensors can and have been used to monitor wildfire events at improved temporal, spatial and radiometric scales, but more focus is being placed on the use of small UAS (sUAS) and sensors to support wildfire observation strategies. The use of sUAS is therefore more critical for TACTICAL management purposes, rather than strategic observations, where small-scale fire developments are critical to understand. This paper will highlight the historical development and use of UAS for fire observations, as well as the current shift in focus to smaller, more affordable UAS for more rapid integration into operational use on wildfire events to support tactical observation strategies, and support wildfire science measurement inprovements.

Preliminary results from a survey of U.S. Forest Service wildfire managers' attitudes toward aviation personnel exposure and risk

Science.gov (United States)

Matthew Wibbenmeyer; Michael Hand; David Calkin

2012-01-01

The U.S. Department of Agriculture, Forest Service (USFS) has, in recent years, increasingly emphasized the importance of safety to its employees, but wildfire management remains a risky endeavor. While wildfire management decisions affecting safety and exposure of firefighters to the wildland fire environment may be aided by decision support tools such the Wildfire...

Safety analysis and risk assessment of the National Ignition Facility

International Nuclear Information System (INIS)

Brereton, S.; McLouth, L.; Odell, B.

1996-01-01

The National Ignition Facility (NIF) is a proposed U.S. Department of Energy inertial confinement laser fusion facility. The candidate sites for locating the NIF are: Los Alamos National Laboratory, Sandia National Laboratory, the Nevada Test Site, and Lawrence Livermore National Laboratory (LLNL), the preferred site. The NIF will operate by focusing 192 laser beams onto a tiny deuterium-tritium target located at the center of a spherical target chamber. The NIF mission is to achieve inertial confinement fusion (ICF) ignition, access physical conditions in matter of interest to nuclear weapons physics, provide an above ground simulation capability for nuclear weapons effects testing, and contribute to the development of inertial fusion for electrical power production. The NIF has been classified as a radiological, low hazard facility on the basis of a preliminary hazards analysis and according to the DOE methodology for facility classification. This requires that a safety analysis be prepared under DOE Order 5481.1B, Safety Analysis and Review System. A draft Preliminary Safety Analysis Report (PSAR) has been written, and this will be finalized later in 1996. This paper summarizes the safety issues associated with the operation of the NIF and the methodology used to study them. It provides a summary of the methodology, an overview of the hazards, estimates maximum routine and accidental exposures for the preferred site of LLNL, and concludes that the risks from NIF operations are low

Rebuilding and new housing development after wildfire

Science.gov (United States)

Patricia M. Alexandre; Miranda H. Mockrin; Susan I. Stewart; Roger B. Hammer; Volker C. Radeloff

2015-01-01

The number of wildland-urban interface communities affected by wildfire is increasing, and both wildfire suppression and losses are costly. However, little is known about post-wildfire response by homeowners and communities after buildings are lost. Our goal was to characterise rebuilding and new development after wildfires across the conterminous United States. We...

Analyzing the transmission of wildfire exposure on a fire-prone landscape in Oregon, USA

Science.gov (United States)

Alan A. Ager; Michelle A. Day; Mark A. Finney; Ken Vance-Borland; Nicole M. Vaillant

2014-01-01

We develop the idea of risk transmission from large wildfires and apply network analyses to understand its importance on a 0.75 million ha US national forest. Wildfires in the western US frequently burn over long distances (e.g., 20–50 km) through highly fragmented landscapes with respect to ownership, fuels, management intensity, population density, and ecological...

Shock Timing Plan for the National Ignition Campaign

Science.gov (United States)

Munro, D. H.; Robey, H. F.; Spears, B. K.; Boehly, T. R.

2006-10-01

We report progress on the design of the shock timing tuning procedure for the 2010 ignition campaign at the National Ignition Facility. Our keyhole target design provides adequate drive surrogacy for us to time the first three shocks empirically. The major risk to our plan is hard x-ray preheat, which can cause the diagnostic window to become opaque.

Post-wildfire recovery of water yield in the Sydney Basin water supply catchments: An assessment of the 2001/2002 wildfires

Science.gov (United States)

Heath, J. T.; Chafer, C. J.; van Ogtrop, F. F.; Bishop, T. F. A.

2014-11-01

Wildfire is a recurring event which has been acknowledged by the literature to impact the hydrological cycle of a catchment. Hence, wildfire may have a significant impact on water yield levels within a catchment. In Australia, studies of the effect of fire on water yield have been limited to obligate seeder vegetation communities. These communities regenerate from seed banks in the ground or within woody fruits and are generally activated by fire. In contrast, the Sydney Basin is dominated by obligate resprouter communities. These communities regenerate from fire resistant buds found on the plant and are generally found in regions where wildfire is a regular occurrence. The 2001/2002 wildfires in the Sydney Basin provided an opportunity to investigate the impacts of wildfire on water yield in a number of catchments dominated by obligate resprouting communities. The overall aim of this study was to investigate whether there was a difference in water yield post-wildfire. Four burnt subcatchments and 3 control subcatchments were assessed. A general additive model was calibrated using pre-wildfire data and then used to predict post-wildfire water yield using post-wildfire data. The model errors were analysed and it was found that the errors for all subcatchments showed similar trends for the post-wildfire period. This finding demonstrates that wildfires within the Sydney Basin have no significant medium-term impact on water yield.

Integration of Lightning- and Human-Caused Wildfire Occurrence Models

DEFF Research Database (Denmark)

Vilar, Lara; Nieto Solana, Hector; Martín, M. Pilar

2010-01-01

Fire risk indices are useful tools for fire prevention actions by fire managers. A fire ignition is either the result of lightning or human activities. In European Mediterranean countries most forest fires are due to human activities. However, lightning is still an important fire ignition source...... probability models at 1 × 1 km grid cell resolution in two regions of Spain: Madrid, which presents a high fire incidence due to human activities; and Aragón, one of the most affected regions in Spain by lightning-fires. For validation, independent fire ignition points were used to compute the Receiver...

Are wildfire management resources in the United States efficiently allocated to protect resources at risk? A case study from Montana

Science.gov (United States)

Derek T. O' Donnell; Tyron J. Venna; David E. Calkin

2014-01-01

Federal wildfire management agencies in the United States are under substantial pressure to reduce and economically justify their expenditures. To support economically efficient management of wildfires, managers need better estimates of the resource benefits and avoided damage costs associated with alternative wildfire management strategies. This paper reports findings...

Perceptions of Post-Wildfire Landscape Change and Recovery

Science.gov (United States)

Kooistra, C. M.; Hall, T. E.; Paveglio, T.; Carroll, M.; Smith, A. M.

2013-12-01

Considering the dynamic nature of the earth and climate systems and the increasing potential for widespread forest disturbances, it is important to understand the implications of landscape changes, and perceptions of changes, on people's responses to forest disturbances. Understanding how people perceive landscape change over time following forest disturbances helps researchers, land managers, and community leaders identify important biophysical and social characteristics that influence the vulnerability of people who experience forest disturbances, as well as their responses to those disturbances. This poster describes people's perceptions of landscape change following a significant wildfire. The lightning ignited Dahl fire burned 12 miles southeast of Roundup, MT mostly on private land in the summer of June 2012. The fire burned approximately 22,000 acres and destroyed 73 residences. We conducted interviews in the summer of 2013 with more than 40 residents, land managers, emergency personnel, and other stakeholders. While interviews covered several topics, this poster focuses on responses to questions regarding perceptions of short- and long-term landscape change after the fire, including both social and biophysical perspectives. Interviews revealed that people's understanding of the role of wildfires as a natural ecosystem process, as well as their connections with the landscape (i.e., sense of place), were important factors that influenced their perceptions of landscape change after the fire. Many respondents discussed the landscape ';recovering' to pre-fire conditions in longer-term timeframes, such as ';multiple generations.' They often referenced previous wildfires, the Hawk Creek fire (1984) and the Majeras fire (2006), by explaining how parts of the landscape affected by the Dahl fire might compare to certain areas of the previous fires. Variations in recovery expectations were often based on perceptions of the severity of the fire (especially temperature

Wildfires in Siberian Mountain Forest

Science.gov (United States)

Kharuk, V.; Ponomarev, E. I.; Antamoshkina, O.

2017-12-01

The annual burned area in Russia was estimated as 0.55 to 20 Mha with >70% occurred in Siberia. We analyzed Siberian wildfires distribution with respect to elevation, slope steepness and exposure. In addition, wildfires temporal dynamic and latitudinal range were analyzed. We used daily thermal anomalies derived from NOAA/AVHRR and Terra/MODIS satellites (1990-2016). Fire return intervals were (FRI) calculated based on the dendrochronology analysis of samples taken from trees with burn marks. Spatial distribution of wildfires dependent on topo features: relative burned area increase with elevation increase (ca. 1100 m), switching to following decrease. The wildfires frequency exponentially decreased within lowlands - highlands transition. Burned area is increasing with slope steepness increase (up to 5-10°). Fire return intervals (FRI) on the southfacing slopes are about 30% longer than on the north facing. Wildfire re-occurrence is decreasing exponentially: 90% of burns were caused by single fires, 8.5% by double fires, 1% burned three times, and on about 0.05% territory wildfires occurred four times (observed period: 75 yr.). Wildfires area and number, as well as FRI, also dependent on latitude: relative burned area increasing exponentially in norward direction, whereas relative fire number is exponentially decreasing. FRI increases in the northward direction: from 80 years at 62°N to 200 years at the Arctic Circle, and to 300 years at the northern limit of closed forests ( 71+°N). Fire frequency, fire danger period and FRI are strongly correlated with incoming solar radiation (r = 0.81 - 0.95). In 21-s century, a positive trend of wildfires number and area observed in mountain areas in all Siberia. Thus, burned area and number of fires in Siberia are significantly increased since 1990th (R2 =0.47, R2 =0.69, respectively), and that increase correlated with air temperatures and climate aridity increases. However, wildfires are essential for supporting fire

A polar-drive shock-ignition design for the National Ignition Facility

Energy Technology Data Exchange (ETDEWEB)

Anderson, K. S.; McKenty, P. W.; Collins, T. J. B.; Craxton, R. S.; Delettrez, J. A.; Marozas, J. A.; Skupsky, S.; Shvydky, A. [Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623 (United States); Betti, R. [Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623 (United States); Fusion Science Center, University of Rochester, Rochester, New York 14623 (United States); Departments of Mechanical Engineering and Physics, University of Rochester, Rochester, New York 14627 (United States); Hohenberger, M.; Theobald, W.; Lafon, M.; Nora, R. [Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623 (United States); Fusion Science Center, University of Rochester, Rochester, New York 14623 (United States)

2013-05-15

Shock ignition [R. Betti et al., Phys. Rev. Lett. 98, 155001 (2007)] is being pursued as a viable option to achieve ignition on the National Ignition Facility (NIF). Shock-ignition target designs use a high-intensity laser spike at the end of a low-adiabat assembly pulse to launch a spherically convergent strong shock to ignite the hot spot of an imploding capsule. A shock-ignition target design for the NIF is presented. One-dimensional simulations indicate an ignition threshold factor of 4.1 with a gain of 58. A polar-drive beam-pointing configuration for shock-ignition experiments on the NIF at 750 kJ is proposed. The capsule design is shown to be robust to the various one- and two-dimensional effects and nonuniformities anticipated on the NIF. The target is predicted to ignite with a gain of 38 when including all anticipated levels of nonuniformity and system uncertainty.

The Ignition Target for the National Ignition Facility

International Nuclear Information System (INIS)

Atherton, L J; Moses, E I; Carlisle, K; Kilkenny, J

2007-01-01

The National Ignition Facility (NIF) is a 192 beam Nd-glass laser facility presently under construction at Lawrence Livermore National Laboratory (LLNL) for performing inertial confinement fusion (ICF) and experiments studying high energy density (HED) science. When completed in 2009, NIF will be able to produce 1.8 MJ, 500 TW of ultraviolet light for target experiments that will create conditions of extreme temperatures (>10 8 K), pressures (10-GBar) and matter densities (> 100 g/cm 3 ). A detailed program called the National Ignition Campaign (NIC) has been developed to enable ignition experiments in 2010, with the goal of producing fusion ignition and burn of a deuterium-tritium (DT) fuel mixture in millimeter-scale target capsules. The first of the target experiments leading up to these ignition shots will begin in 2008. Targets for the National Ignition Campaign are both complex and precise, and are extraordinarily demanding in materials fabrication, machining, assembly, cryogenics and characterization. An overview of the campaign for ignition will be presented, along with technologies for target fabrication, assembly and metrology and advances in growth and x-ray imaging of DT ice layers. The sum of these efforts represents a quantum leap in target precision, characterization, manufacturing rate and flexibility over current state-of-the-art

Economic optimisation of wildfire intervention activities

Science.gov (United States)

David T. Butry; Jeffrey P. Prestemon; Karen L. Abt; Ronda Sutphen

2010-01-01

We describe how two important tools of wildfire management, wildfire prevention education and prescribed fire for fuels management, can be coordinated to minimise the combination of management costs and expected societal losses resulting from wildland fire. We present a long-run model that accounts for the dynamics of wildfire, the effects of fuels management on...

Succession Stages of Tundra Plant Communities Following Wildfire Disturbance in Arctic Alaska

Science.gov (United States)

Breen, A. L.; Hollingsworth, T. N.; Mack, M. C.; Jones, B. M.

2015-12-01

Rapid climate change is affecting climate-sensitive disturbance regimes throughout the world. In particular, the impacts of climate change on Arctic disturbance regimes are poorly understood because landscape-scale disturbances are infrequent or occur in remote localities. Wildfire in Arctic Alaska is presently limited by ignition source and favorable burn weather. With rapid climate change, a lengthening growing season, and subsequent increase in plant biomass and productivity, wildfire frequency and annual area burned in tundra ecosystems is expected to increase over the next century. Yet, post-fire tundra vegetation succession is inadequately characterized except at a few point locations. We identify succession stages of tussock tundra communities following wildfire using a chronosequence of 65 relevés in 10 tundra fire scars (1971-2011) and nearby unburned tundra from sites on the Seward Peninsula and northern foothills of the Brooks Range. We used the Braun-Blanquét approach to classify plant communities, and applied nonmetric multidimentional scaling (NMDS) to identify ecological gradients underlying community differentiation. The ordination revealed a clear differentiation between unburned and burned tundra communities. Ecological gradients, reflected by ordination axes, correspond to fire history (e.g., time since last fire, number of times burned, burn severity) and a complex productivity gradient. Post-fire species richness is less than unburned tundra; primarily reflected as a decrease in lichen species and turnover of bryophyte species immediately post-fire. Species richness of grasses increases post-fire and is greatest in communities that burned more than once in the past 30 years. Shrub cover and total aboveground biomass are greatest in repeat burn sites. We review and discuss our results focusing on the implications of a changing tundra fire regime, its effect on vegetation succession trajectories, and subsequent rates of carbon sequestration and

Shock Tube Ignition Delay Data Affected by Localized Ignition Phenomena

KAUST Repository

Javed, Tamour

2016-12-29

Shock tubes have conventionally been used for measuring high-temperature ignition delay times ~ O(1 ms). In the last decade or so, the operating regime of shock tubes has been extended to lower temperatures by accessing longer observation times. Such measurements may potentially be affected by some non-ideal phenomena. The purpose of this work is to measure long ignition delay times for fuels exhibiting negative temperature coefficient (NTC) and to assess the impact of shock tube non-idealities on ignition delay data. Ignition delay times of n-heptane and n-hexane were measured over the temperature range of 650 – 1250 K and pressures near 1.5 atm. Driver gas tailoring and long length of shock tube driver section were utilized to measure ignition delay times as long as 32 ms. Measured ignition delay times agree with chemical kinetic models at high (> 1100 K) and low (< 700 K) temperatures. In the intermediate temperature range (700 – 1100 K), however, significant discrepancies are observed between the measurements and homogeneous ignition delay simulations. It is postulated, based on experimental observations, that localized ignition kernels could affect the ignition delay times at the intermediate temperatures, which lead to compression (and heating) of the bulk gas and result in expediting the overall ignition event. The postulate is validated through simple representative computational fluid dynamic simulations of post-shock gas mixtures which exhibit ignition advancement via a hot spot. The results of the current work show that ignition delay times measured by shock tubes may be affected by non-ideal phenomena for certain conditions of temperature, pressure and fuel reactivity. Care must, therefore, be exercised in using such data for chemical kinetic model development and validation.

Dormant season grazing may decrease wildfire probability by increasing fuel moisture and reducing fuel amount and continuity

Science.gov (United States)

1. Wildfire is an ecological and economic risk for many semi-arid rangelands across the globe. This coupled with extreme wildfire seasons and mega-fires over the last decade have resulted in a call for more pre-suppression management actions. Dormant season grazing has been suggested as a treatment...

Wildfire Smoke Health Watch

Centers for Disease Control (CDC) Podcasts

2012-07-23

Smoke from wildfires can be dangerous to your health. In this podcast, you will learn the health threats of wildfire smoke and steps you can take to minimize these effects.  Created: 7/23/2012 by Office of Public Health Preparedness and Response (PHPR).   Date Released: 7/23/2012.

Estimation of wildfire size and risk changes due to fuels treatments

Science.gov (United States)

M. A. Cochrane; C. J. Moran; M. C. Wimberly; A. D. Baer; M. A. Finney; K. L. Beckendorf; J. Eidenshink; Z. Zhu

2012-01-01

Human land use practices, altered climates, and shifting forest and fire management policies have increased the frequency of large wildfires several-fold. Mitigation of potential fire behaviour and fire severity have increasingly been attempted through pre-fire alteration of wildland fuels using mechanical treatments and prescribed fires. Despite annual treatment of...

What are the most fire-dangerous atmospheric circulations in the Eastern-Mediterranean? Analysis of the synoptic wildfire climatology.

Science.gov (United States)

Paschalidou, A K; Kassomenos, P A

2016-01-01

Wildfire management is closely linked to robust forecasts of changes in wildfire risk related to meteorological conditions. This link can be bridged either through fire weather indices or through statistical techniques that directly relate atmospheric patterns to wildfire activity. In the present work the COST-733 classification schemes are applied in order to link wildfires in Greece with synoptic circulation patterns. The analysis reveals that the majority of wildfire events can be explained by a small number of specific synoptic circulations, hence reflecting the synoptic climatology of wildfires. All 8 classification schemes used, prove that the most fire-dangerous conditions in Greece are characterized by a combination of high atmospheric pressure systems located N to NW of Greece, coupled with lower pressures located over the very Eastern part of the Mediterranean, an atmospheric pressure pattern closely linked to the local Etesian winds over the Aegean Sea. During these events, the atmospheric pressure has been reported to be anomalously high, while anomalously low 500hPa geopotential heights and negative total water column anomalies were also observed. Among the various classification schemes used, the 2 Principal Component Analysis-based classifications, namely the PCT and the PXE, as well as the Leader Algorithm classification LND proved to be the best options, in terms of being capable to isolate the vast amount of fire events in a small number of classes with increased frequency of occurrence. It is estimated that these 3 schemes, in combination with medium-range to seasonal climate forecasts, could be used by wildfire risk managers to provide increased wildfire prediction accuracy. Copyright © 2015 Elsevier B.V. All rights reserved.

Regional modeling of large wildfires under current and potential future climates in Colorado and Wyoming, USA

Science.gov (United States)

West, Amanda; Kumar, Sunil; Jarnevich, Catherine S.

2016-01-01

Regional analysis of large wildfire potential given climate change scenarios is crucial to understanding areas most at risk in the future, yet wildfire models are not often developed and tested at this spatial scale. We fit three historical climate suitability models for large wildfires (i.e. ≥ 400 ha) in Colorado andWyoming using topography and decadal climate averages corresponding to wildfire occurrence at the same temporal scale. The historical models classified points of known large wildfire occurrence with high accuracies. Using a novel approach in wildfire modeling, we applied the historical models to independent climate and wildfire datasets, and the resulting sensitivities were 0.75, 0.81, and 0.83 for Maxent, Generalized Linear, and Multivariate Adaptive Regression Splines, respectively. We projected the historic models into future climate space using data from 15 global circulation models and two representative concentration pathway scenarios. Maps from these geospatial analyses can be used to evaluate the changing spatial distribution of climate suitability of large wildfires in these states. April relative humidity was the most important covariate in all models, providing insight to the climate space of large wildfires in this region. These methods incorporate monthly and seasonal climate averages at a spatial resolution relevant to land management (i.e. 1 km2) and provide a tool that can be modified for other regions of North America, or adapted for other parts of the world.

Development and application of a probabilistic method for wildfire suppression cost modeling

Science.gov (United States)

Matthew P. Thompson; Jessica R. Haas; Mark A. Finney; David E. Calkin; Michael S. Hand; Mark J. Browne; Martin Halek; Karen C. Short; Isaac C. Grenfell

2015-01-01

Wildfire activity and escalating suppression costs continue to threaten the financial health of federal land management agencies. In order to minimize and effectively manage the cost of financial risk, agencies need the ability to quantify that risk. A fundamental aim of this research effort, therefore, is to develop a process for generating risk-based metrics for...

Radiological assessments for the National Ignition Facility

International Nuclear Information System (INIS)

Hong, Kou-John; Lazaro, M.A.

1996-01-01

The potential radiological impacts of the National Ignition Facility (NIF), a proposed facility for fusion ignition and high energy density experiments, were assessed for five candidate sites to assist in site selection. The GENII computer program was used to model releases of radionuclides during normal NIF operations and a postulated accident and to calculate radiation doses to the public. Health risks were estimated by converting the estimated doses into health effects using a standard cancer fatality risk factor. The greatest calculated radiation dose was less than one thousandth of a percent of the dose received from natural background radiation; no cancer fatalities would be expected to occur in the public as the result of normal operations. The highest dose conservatively estimated to result from a postulated accident could lead to one in one million risk of cancer

Spatial and temporal changes in land cover and its relation to the wildfire risk in Montes de Zuera (NE-Spain)

Science.gov (United States)

Iñiguez-Remón, E.; Badía-Villas, D.; Ibarra-Benlloch, P.

2012-04-01

Land cover changes in a territory can be as result of the diverse human activities, and also, by the dynamic natural ecosystem. The analysis of these changes constitutes a fundamental indicator in improving the knowledge towards a potential sustainable development (OSE, 2006). This paper analyzes the evolution of the land cover at detailed scale 1:5000, along the years 1957, 1984, and 2005, in the Montes de Zuera (UTM: 665000-680000 East /4640000-4650000 North), nearby Zaragoza city (NE-Spain). Despite they are located in the midst of the semiarid Central Ebro Basin, the area have an uncommon, extensive and dense forest cover. For these reasons, Montes de Zuera form part of the "Natura 2000 Network" of Aragon. Because this region has a high incidence of wildfires and, as a measure to prevent them, land cover changes have been analyzed in this study. To get this objective, a methodology is developed based on GIS and Remote Sensing tools, and this makes it possible to establish the relationship between the dynamic land cover and "fire hazard". According to FAO (1986), fire hazard is the measure of risk of wildfire, which is explained by the presence of combustible materials available to burn (Chuvieco et al, 2004). It is understood that the areas with major fire hazard present a high vulnerability to suffer vast wildfires. To develop this work, the type of vegetation, its distribution and the state of maturity of the forest masses are analyzed. Moreover, the wildfires that occurred during the last five decades have been located, and the forest masses and the processes (anthropic and natural) associated to them have been characterized in the regions affected by vast wildfires. Moreover, the cartography of fire hazard is obtained, and this is useful tool to fre prevention and to promote the sustainable management of the forest masses. Two regions with high rate of fire hazards are differentiated (region 1 and region 2). The Aleppo pine cover occupies the majority of

Ignition and Inertial Confinement Fusion at The National Ignition Facility

International Nuclear Information System (INIS)

Moses, E.

2009-01-01

The National Ignition Facility (NIF), the world's largest and most powerful laser system for inertial confinement fusion (ICF) and for studying high-energy-density (HED) science, is now operational at Lawrence Livermore National Laboratory (LLNL). The NIF is now conducting experiments to commission the laser drive, the hohlraum and the capsule and to develop the infrastructure needed to begin the first ignition experiments in FY 2010. Demonstration of ignition and thermonuclear burn in the laboratory is a major NIF goal. NIF will achieve this by concentrating the energy from the 192 beams into a mm 3 -sized target and igniting a deuterium-tritium mix, liberating more energy than is required to initiate the fusion reaction. NIF's ignition program is a national effort managed via the National Ignition Campaign (NIC). The NIC has two major goals: execution of DT ignition experiments starting in FY2010 with the goal of demonstrating ignition and a reliable, repeatable ignition platform by the conclusion of the NIC at the end of FY2012. The NIC will also develop the infrastructure and the processes required to operate NIF as a national user facility. The achievement of ignition at NIF will demonstrate the scientific feasibility of ICF and focus worldwide attention on laser fusion as a viable energy option. A laser fusion-based energy concept that builds on NIF, known as LIFE (Laser Inertial Fusion Energy), is currently under development. LIFE is inherently safe and can provide a global carbon-free energy generation solution in the 21st century. This paper describes recent progress on NIF, NIC, and the LIFE concept.

Pattern and process of prescribed fires influence effectiveness at reducing wildfire severity in dry coniferous forests

Science.gov (United States)

Arkle, Robert S.; Pilliod, David S.; Welty, Justin L.

2012-01-01

We examined the effects of three early season (spring) prescribed fires on burn severity patterns of summer wildfires that occurred 1–3 years post-treatment in a mixed conifer forest in central Idaho. Wildfire and prescribed fire burn severities were estimated as the difference in normalized burn ratio (dNBR) using Landsat imagery. We used GIS derived vegetation, topography, and treatment variables to generate models predicting the wildfire burn severity of 1286–5500 30-m pixels within and around treated areas. We found that wildfire severity was significantly lower in treated areas than in untreated areas and significantly lower than the potential wildfire severity of the treated areas had treatments not been implemented. At the pixel level, wildfire severity was best predicted by an interaction between prescribed fire severity, topographic moisture, heat load, and pre-fire vegetation volume. Prescribed fire severity and vegetation volume were the most influential predictors. Prescribed fire severity, and its influence on wildfire severity, was highest in relatively warm and dry locations, which were able to burn under spring conditions. In contrast, wildfire severity peaked in cooler, more mesic locations that dried later in the summer and supported greater vegetation volume. We found considerable evidence that prescribed fires have landscape-level influences within treatment boundaries; most notable was an interaction between distance from the prescribed fire perimeter and distance from treated patch edges, which explained up to 66% of the variation in wildfire severity. Early season prescribed fires may not directly target the locations most at risk of high severity wildfire, but proximity of these areas to treated patches and the discontinuity of fuels following treatment may influence wildfire severity and explain how even low severity treatments can be effective management tools in fire-prone landscapes.

Recent progress in ignition fusion research on the National Ignition Facility

International Nuclear Information System (INIS)

Leeper, Ramon J.

2011-01-01

This paper will review the ignition fusion research program that is currently being carried out on the National Ignition Facility (NIF) located at Lawrence Livermore National Laboratory. This work is being conducted under the auspices of the National Ignition Campaign (NIC) that is a broad collaboration of national laboratories and universities that together have developed a detailed research plan whose goal is ignition in the laboratory. The paper will begin with a description of the NIF facility and associated experimental facilities. The paper will then focus on the ignition target and hohlraum designs that will be tested in the first ignition attempts on NIF. The next topic to be introduced will be a description of the diagnostic suite that has been developed for the initial ignition experiments on NIF. The paper will then describe the experimental results that were obtained in experiments conducted during the fall of 2009 on NIF. Finally, the paper will end with a description of the detailed experimental plans that have been developed for the first ignition campaign that will begin later this year. (author)

Net benefits of wildfire prevention education efforts

Science.gov (United States)

Jeffrey P. Prestemon; David T. Butry; Karen L. Abt; Ronda Sutphen

2010-01-01

Wildfire prevention education efforts involve a variety of methods, including airing public service announcements, distributing brochures, and making presentations, which are intended to reduce the occurrence of certain kinds of wildfires. A Poisson model of preventable Florida wildfires from 2002 to 2007 by fire management region was developed. Controlling for...

The economic benefits of wildfire prevention education

Science.gov (United States)

L.A. Hermansen-Baez; J.P. Prestemon; D.T. Butry; K.L. Abt; R. Sutphen

2011-01-01

While there are many activities that can limit damages from wildfires, such as firefighting efforts and prescribed burning, wildfire prevention education programs can be particularly beneficial. This was confirmed through a study conducted by the Southern Research Station and the National Institute of Standards and Technology that demonstrated that wildfire prevention...

Wildfires in Chernobyl-contaminated forests and risks to the population and the environment: a new nuclear disaster about to happen?

Science.gov (United States)

Evangeliou, Nikolaos; Balkanski, Yves; Cozic, Anne; Hao, Wei Min; Møller, Anders Pape

2014-12-01

Radioactive contamination in Ukraine, Belarus and Russia after the Chernobyl accident left large rural and forest areas to their own fate. Forest succession in conjunction with lack of forest management started gradually transforming the landscape. During the last 28 years dead wood and litter have dramatically accumulated in these areas, whereas climate change has increased temperature and favored drought. The present situation in these forests suggests an increased risk of wildfires, especially after the pronounced forest fires of 2010, which remobilized Chernobyl-deposited radioactive materials transporting them thousand kilometers far. For the aforementioned reasons, we study the consequences of different forest fires on the redistribution of (137)Cs. Using the time frequency of the fires that occurred in the area during 2010, we study three scenarios assuming that 10%, 50% and 100% of the area are burnt. We aim to sensitize the scientific community and the European authorities for the foreseen risks from radioactivity redistribution over Europe. The global model LMDZORINCA that reads deposition density of radionuclides and burnt area from satellites was used, whereas risks for the human and animal population were calculated using the Linear No-Threshold (LNT) model and the computerized software ERICA Tool, respectively. Depending on the scenario, whereas between 20 and 240 humans may suffer from solid cancers, of which 10-170 may be fatal. ERICA predicts insignificant changes in animal populations from the fires, whereas the already extreme radioactivity background plays a major role in their living quality. The resulting releases of (137)Cs after hypothetical wildfires in Chernobyl's forests are classified as high in the International Nuclear Events Scale (INES). The estimated cancer incidents and fatalities are expected to be comparable to those predicted for Fukushima. This is attributed to the fact that the distribution of radioactive fallout after the

Wildfires in Chernobyl-contaminated forests and risks to the population and the environment: A new nuclear disaster about to happen?

International Nuclear Information System (INIS)

Evangeliou, Nikolaos; Balkanski, Yves; Cozic, Anne

2014-01-01

Radioactive contamination in Ukraine, Belarus and Russia after the Chernobyl accident left large rural and forest areas to their own fate. Forest succession in conjunction with lack of forest management started gradually transforming the landscape. During the last 28 years dead wood and litter have dramatically accumulated in these areas, whereas climate change has increased temperature and favored drought. The present situation in these forests suggests an increased risk of wildfires, especially after the pronounced forest fires of 2010, which re-mobilized Chernobyl-deposited radioactive materials transporting them thousand kilometers far. For the aforementioned reasons, we study the consequences of different forest fires on the redistribution of 137 Cs. Using the time frequency of the fires that occurred in the area during 2010, we study three scenarios assuming that 10%, 50% and 100% of the area are burnt. We aim to sensitize the scientific community and the European authorities for the foreseen risks from radioactivity redistribution over Europe. The global model LMDZORINCA that reads deposition density of radionuclides and burnt area from satellites was used, whereas risks for the human and animal population were calculated using the Linear No-Threshold (LNT) model and the computerized software ERICA Tool, respectively. Depending on the scenario, whereas between 20 and 240 humans may suffer from solid cancers, of which 10-170 may be fatal. ERICA predicts insignificant changes in animal populations from the fires, whereas the already extreme radioactivity background plays a major role in their living quality. The resulting releases of 137 Cs after hypothetical wildfires in Chernobyl's forests are classified as high in the International Nuclear Events Scale (INES). The estimated cancer incidents and fatalities are expected to be comparable to those predicted for Fukushima. This is attributed to the fact that the distribution of radioactive fallout after the

Transboundary Collaborations to Enhance Wildfire Suppression in Protected Areas of the Black Sea Region

Directory of Open Access Journals (Sweden)

G. N. Zaimes

2016-05-01

Full Text Available For the most effective and efficient management of certain natural resources (e.g. protected areas and disasters (e.g. wildfires transboundary approaches are needed. In addition in the management of protected areas, the role of wildfire should be incorporated, something that was ignored in the past and led to catastrophic wildfires. The Black Sea is a region that wildfires in the protected areas are expected to increase. This has to do with the abandonment of rural areas and the higher temperatures, especially during summer, due to climate change. Interesting is also the fact that some countries of the region have extensive experience while other do not have neither the experience nor the necessary infrastructures to face large wildfires. A transboundary collaboration would be very beneficial to the countries with limited experiences and capacities to suppress wildfires. The objective of this study is to be proactive by developing innovative tools to help suppress wildfires and enhancing the knowledge on wildfires and protected areas. The innovative tools included 4 different research activities and products. Firstly, an online Digital Geodatabase for the six pilot areas was developed. Next forest fire fuels and maps were developed while a forest fire behavior model was run to create the overall fire risk maps for the pilot areas. To estimate water resources and watershed streamflows the hydrologic model SWAT was validated and calibrated for the pilot areas. The final activities included a multi-criteria decision analysis to select the optimal location of the water reservoirs and the use of spatial analyst to provide the optimal routes to reach reservoirs by the fire vehicles. To enhance the responsible agency personnel along with stakeholders knowledge of the region, a Neighborhood Network with regular quarterly meetings was established. Participants for all six project countries were present in the meetings. Overall, new tool that will enhance

Progress Toward Ignition on the National Ignition Facility

International Nuclear Information System (INIS)

Kauffman, R.L.

2011-01-01

The principal approach to ignition on the National Ignition Facility (NIF) is indirect drive. A schematic of an ignition target is shown in Figure 1. The laser beams are focused through laser entrance holes at each end of a high-Z cylindrical case, or hohlraum. The lasers irradiate the hohlraum walls producing x-rays that ablate and compress the fuel capsule in the center of the hohlraum. The hohlraum is made of Au, U, or other high-Z material. For ignition targets, the hohlraum is ∼0.5 cm diameter by ∼1 cm in length. The hohlraum absorbs the incident laser energy producing x-rays for symmetrically imploding the capsule. The fuel capsule is a ∼2-mm-diameter spherical shell of CH, Be, or C filled with DT fuel. The DT fuel is in the form of a cryogenic layer on the inside of the capsule. X-rays ablate the outside of the capsule, producing a spherical implosion. The imploding shell stagnates in the center, igniting the DT fuel. NIC has overseen installation of all of the hardware for performing ignition experiments, including commissioning of approximately 50 diagnostic systems in NIF. The diagnostics measure scattered optical light, x-rays from the hohlraum over the energy range from 100 eV to 500 keV, and x-rays, neutrons, and charged particles from the implosion. An example of a diagnostic is the Magnetic Recoil Spectrometer (MRS) built by a collaboration of scientists from MIT, UR-LLE, and LLNL shown in Figure 2. MRS measures the neutron spectrum from the implosion, providing information on the neutron yield and areal density that are metrics of the quality of the implosion. Experiments on NIF extend ICF research to unexplored regimes in target physics. NIF can produce more than 50 times the laser energy and more than 20 times the power of any previous ICF facility. Ignition scale hohlraum targets are three to four times larger than targets used at smaller facilities, and the ignition drive pulses are two to five times longer. The larger targets and longer

Mortality related to air pollution with the moscow heat wave and wildfire of 2010.

Science.gov (United States)

Shaposhnikov, Dmitry; Revich, Boris; Bellander, Tom; Bedada, Getahun Bero; Bottai, Matteo; Kharkova, Tatyana; Kvasha, Ekaterina; Lezina, Elena; Lind, Tomas; Semutnikova, Eugenia; Pershagen, Göran

2014-05-01

Prolonged high temperatures and air pollution from wildfires often occur together, and the two may interact in their effects on mortality. However, there are few data on such possible interactions. We analyzed day-to-day variations in the number of deaths in Moscow, Russia, in relation to air pollution levels and temperature during the disastrous heat wave and wildfire of 2010. Corresponding data for the period 2006-2009 were used for comparison. Daily average levels of PM10 and ozone were obtained from several continuous measurement stations. The daily number of nonaccidental deaths from specific causes was extracted from official records. Analyses of interactions considered the main effect of temperature as well as the added effect of prolonged high temperatures and the interaction with PM10. The major heat wave lasted for 44 days, with 24-hour average temperatures ranging from 24°C to 31°C and PM10 levels exceeding 300 μg/m on several days. There were close to 11,000 excess deaths from nonaccidental causes during this period, mainly among those older than 65 years. Increased risks also occurred in younger age groups. The most pronounced effects were for deaths from cardiovascular, respiratory, genitourinary, and nervous system diseases. Continuously increasing risks following prolonged high temperatures were apparent during the first 2 weeks of the heat wave. Interactions between high temperatures and air pollution from wildfires in excess of an additive effect contributed to more than 2000 deaths. Interactions between high temperatures and wildfire air pollution should be considered in risk assessments regarding health consequences of climate change.

Understanding change: Wildfire in Larimer County, Colorado

Science.gov (United States)

Hannah Brenkert-Smith; Patricia A. Champ

2013-01-01

Wildfire activity continues to plague communities in the American West. Three causes are often identified as key contributors to the wildfire problem: accumulated fuels on public lands due to a history of suppressing wildfires; climate change; and an influx of residents into fire prone areas referred to as the wildland-urban interface (WUI). The latter of these...

Understanding change: Wildfire in Boulder County, Colorado

Science.gov (United States)

Hannah Brenkert-Smith; Patricia A. Champ; Amy L. Telligman

2013-01-01

Wildfire activity continues to plague communities in the American West. Three causes are often identified as key contributors to the wildfire problem: accumulated fuels on public lands due to a history of suppressing wildfires; climate change; and an influx of residents into fire prone areas referred to as the wildland-urban interface (WUI). The latter of these...

Mitigating wildfire carbon loss in managed northern peatlands through restoration

Science.gov (United States)

Granath, Gustaf; Moore, Paul A.; Lukenbach, Maxwell C.; Waddington, James M.

2016-06-01

Northern peatlands can emit large amounts of carbon and harmful smoke pollution during a wildfire. Of particular concern are drained and mined peatlands, where management practices destabilize an array of ecohydrological feedbacks, moss traits and peat properties that moderate water and carbon losses in natural peatlands. Our results demonstrate that drained and mined peatlands in Canada and northern Europe can experience catastrophic deep burns (>200 t C ha-1 emitted) under current weather conditions. Furthermore, climate change will cause greater water losses in these peatlands and subject even deeper peat layers to wildfire combustion. However, the rewetting of drained peatlands and the restoration of mined peatlands can effectively lower the risk of these deep burns, especially if a new peat moss layer successfully establishes and raises peat moisture content. We argue that restoration efforts are a necessary measure to mitigate the risk of carbon loss in managed peatlands under climate change.

Does charge transfer correlate with ignition probability?

International Nuclear Information System (INIS)

Holdstock, Paul

2008-01-01

Flammable or explosive atmospheres exist in many industrial environments. The risk of ignition caused by electrostatic discharges is very real and there has been extensive study of the incendiary nature of sparks and brush discharges. It is clear that in order to ignite a gas, an amount of energy needs to be delivered to a certain volume of gas within a comparatively short time. It is difficult to measure the energy released in an electrostatic discharge directly, but it is possible to approximate the energy in a spark generated from a well defined electrical circuit. The spark energy required to ignite a gas, vapour or dust cloud can be determined by passing such sparks through them. There is a relationship between energy and charge in a capacitive circuit and so it is possible to predict whether or not a spark discharge will cause an ignition by measuring the charge transferred in the spark. Brush discharges are in many ways less well defined than sparks. Nevertheless, some work has been done that has established a relationship between charge transferred in brush discharges and the probability of igniting a flammable atmosphere. The question posed by this paper concerns whether such a relationship holds true in all circumstances and if there is a universal correlation between charge transfer and ignition probability. Data is presented on discharges from textile materials that go some way to answering this question.

Amphibian responses to wildfire in the western united states: Emerging patterns from short-term studies

Science.gov (United States)

Hossack, B.R.; Pilliod, D.S.

2011-01-01

The increased frequency and severity of large wildfires in the western United States is an important ecological and management issue with direct relevance to amphibian conservation. Although the knowledge of fire effects on amphibians in the region is still limited relative to most other vertebrate species, we reviewed the current literature to determine if there are evident patterns that might be informative for conservation or management strategies. Of the seven studies that compared pre- and post-wildfire data on a variety of metrics, ranging from amphibian occupancy to body condition, two reported positive responses and five detected negative responses by at least one species. Another seven studies used a retrospective approach to compare effects of wildfire on populations: two studies reported positive effects, three reported negative effects from wildfire, and two reported no effects. All four studies that included plethodontid salamanders reported negative effects on populations or individuals; these effects were greater in forests where fire had been suppressed and in areas that burned with high severity. Species that breed in streams are also vulnerable to post-wildfire changes in habitat, especially in the Southwest. Wildfire is also important for maintaining suitable habitat for diverse amphibian communities, although those results may not be evident immediately after an area burns. We expect that wildfire will extirpate few healthy amphibian populations, but it is still unclear how populations will respond to wildfire in the context of land management (including pre- and post-fire timber harvest) and fragmentation. Wildfire may also increase the risk of decline or extirpation for small, isolated, or stressed (e.g., from drought or disease) populations. Improved understanding of how these effects vary according to changes in fire frequency and severity are critical to form more effective conservation strategies for amphibians in the western United States.

Safety Implementation of Hydrogen Igniters and Recombiners for Nuclear Power Plant Severe Accident Management

Institute of Scientific and Technical Information of China (English)

XIAO Jianjun; ZHOU Zhiwei; JING Xingqing

2006-01-01

Hydrogen combustion in a nuclear power plant containment building may threaten the integrity of the containment. Hydrogen recombiners and igniters are two methods to reduce hydrogen levels in containment buildings during severe accidents. The purpose of this paper is to evaluate the safety implementation of hydrogen igniters and recombiners. This paper analyzes the risk of deliberate hydrogen ignition and investigates three mitigation measures using igniters only, hydrogen recombiners only or a combination of recombiners and igniters. The results indicate that steam can effectively control the hydrogen flame acceleration and the deflagration-to-detonation transition.

Electrostatic hazards of charging of bedclothes and ignition in medical facilities.

Science.gov (United States)

Endo, Yuta; Ohsawa, Atsushi; Yamaguma, Mizuki

2018-02-26

We investigated the charge generated on bedclothes (cotton and polyester) during bedding exchange with different humidities and the ignitability of an alcohol-based hand sanitizer (72.3 mass% ethanol) due to static spark with different temperatures to identify the hazards of electrostatic shocks and ignitions occurring previously in medical facilities. The results indicated that charging of the polyester bedclothes may induce a human body potential of over about 10 kV, resulting in shocks even at a relative humidity of 50%, and a human body potential of higher than about 8 kV can cause a risk for the ignition of the hand sanitizer. The grounding of human bodies via footwear and flooring, therefore, is essential to avoid such hazards (or to reduce such risks).

Assessing Wildland Fire Risk Transmission to Communities in Northern Spain

Directory of Open Access Journals (Sweden)

Fermín J. Alcasena

2017-01-01

Full Text Available We assessed potential economic losses and transmission to residential houses from wildland fires in a rural area of central Navarra (Spain. Expected losses were quantified at the individual structure level (n = 306 in 14 rural communities by combining fire model predictions of burn probability and fire intensity with susceptibility functions derived from expert judgement. Fire exposure was estimated by simulating 50,000 fire events that replicated extreme (97th percentile historical fire weather conditions. Spatial ignition probabilities were used in the simulations to account for non-random ignitions, and were estimated from a fire occurrence model generated with an artificial neural network. The results showed that ignition probability explained most of spatial variation in risk, with economic value of structures having only a minor effect. Average expected loss to residential houses from a single wildfire event in the study area was 7955€, and ranged from a low of 740 to the high of 28,725€. Major fire flow-paths were analyzed to understand fire transmission from surrounding municipalities and showed that incoming fires from the north exhibited strong pathways into the core of the study area, and fires spreading from the south had the highest likelihood of reaching target residential structures from the longest distances (>5 km. Community firesheds revealed the scale of risk to communities and extended well beyond administrative boundaries. The results provided a quantitative risk assessment that can be used by insurance companies and local landscape managers to prioritize and allocate investments to treat wildland fuels and identify clusters of high expected loss within communities. The methodological framework can be extended to other fire-prone southern European Union countries where communities are threatened by large wildland fires.

Rapid growth of the US wildland-urban interface raises wildfire risk

Science.gov (United States)

Volker C. Radeloff; David P. Helmers; H. Anu Kramer; Miranda H. Mockrin; Patricia M. Alexandre; Avi Bar-Massada; Van Butsic; Todd J. Hawbaker; Sebastián Martinuzzi; Alexandra D. Syphard; Susan I. Stewart

2018-01-01

The wildland-urban interface (WUI) is the area where houses and wildland vegetation meet or intermingle, and where wildfire problems are most pronounced. Here we report that the WUI in the United States grew rapidly from 1990 to 2010 in terms of both number of new houses (from 30.8 to 43.4 million; 41% growth) and land area (from 581,000 to 770,000 km2...

Measuring the consequences of wildfires in a Bayesian network with vulnerability and exposure indicators

Science.gov (United States)

Papakosta, Panagiota; Botzler, Sebastian; Krug, Kai; Straub, Daniel

2013-04-01

Mediterranean climate type areas have always been experiencing fire events. However, population growth and expansion of urban centers into wildland areas during the 20th century (expansion of wildland-urban interface) has increased the threat to humans and their activities. Life and property losses, damage on infrastructure and crops, and forest degradation are some of the damages caused by wildfires. Although fires repeatedly occur along the Mediterranean basin, not all areas have experienced severe consequences. The extent of damage by wildfires is influenced by several factors, such as population density, vegetation type, topography, weather conditions and social preparedness [1]. Wildfire consequence estimation by means of vulnerability and exposure indicators is an essential part of wildfire risk analysis. Vulnerability indicators express the conditions that increase the susceptibility of a site to the impact of wildfires and exposure indicators describe the elements at risk [2],[3]. Appropriate indicators to measure wildfire vulnerability and exposure can vary with scale and site. The consequences can be classified into economic, social, environmental and safety, and they can be tangible (human life losses, buildings damaged) or intangible (damage of cultural heritage site). As a consequence, a variety of approaches exist and there is a lack of generalized unified easy-to-implement methodologies. In this study we present a methodology for measuring consequences of wildfires in a Mediterranean area in the mesoscale (1 km² spatial resolution). Vulnerability and exposure indicators covering all consequence levels are identified and their interrelations are stressed. Variables such as building materials, roofing type, and average building values are included in the economic vulnerability level. Safety exposure is expressed by population density, demographic structure, street density and distance to closest fire station. Environmental vulnerability of protected

A burning problem: social dynamics of disaster risk reduction through wildfire mitigation

Science.gov (United States)

Susan Charnley; Melissa R. Poe; Alan A. Ager; Thomas A. Spies; Emily K. Platt; Keith A. Olsen

2015-01-01

Disasters result from hazards affecting vulnerable people. Most disasters research by anthropologists focuses on vulnerability; this article focuses on natural hazards. We use the case of wildfire mitigation on United States Forest Service lands in the northwestern United States to examine social, political, and economic variables at multiple scales that influence fire...

Future Wildfire and Managed Fire Interactions in the Lake Tahoe Basin

Science.gov (United States)

Scheller, R.; Kretchun, A.

2017-12-01

Managing large forested landscape in the context of a changing climate and altered disturbance regimes presents new challenges and require integrated assessments of forest disturbance, management, succession, and the carbon cycle. Successful management under these circumstances will require information about trade-offs among multiple objectives and opportunities for spatially optimized landscape-scale management. Improved information about the effects of climate on forest communities, disturbance feedbacks, and the effectiveness of mitigation strategies enables actionable options for landscape managers. We evaluated the effects of fire suppression, wildfires, and forest fuel (thinning) treatments on the long-term carbon storage potential for Lake Tahoe Basin (LTB) forests under various climate futures. We simulated management scenarios that encompass fuel treatments across the larger landscape, beyond the Wildland Urban Interface. We improved upon current fire modeling under climate change via an integrated fire modeling module that, a) explicitly captures the influence of climate, fuels, topography, active fire management (e.g., fire suppression), and fuel treatments, and b) can be parameterized from available data, e.g., remote sensing, field reporting, fire databases, expert opinion. These improvements increase geographic flexibility and decrease reliance on broad historical fire regime statistics - imperfect targets for a no analog future and require minimal parameterization and calibration. We assessed the interactions among fuel treatments, prescribe fire, fire suppression, and stochastically recurring wildfires. Predicted changes in climate and ignition patterns in response to future climatic conditions, vegetation dynamics, and fuel treatments indicate larger potential long-term effects on C emissions, forest structure, and forest composition than prior studies.

Spatial and temporal patterns of wildfires in the Northern Alps

Science.gov (United States)

Heel, Michael; Sass, Oliver; Friedmann, Arne; Wetzel, Karl-Friedrich

2010-05-01

Wildfires in the northern Alps are rare compared to e.g. the Mediterranean region. However, fires occurring on the dry, south-exposed slopes of the inner-alpine valleys can constitute a significant disturbance of the ecosystems in the sub-alpine belt. We reconstructed the younger regional wildfire history (last few centuries) of a part of the the Northern Limestone Alps using chronicles, forestry and fire brigade records as well as historical pictures (postcards, aerial photos etc.), local names and interviews with local people. The long-term fire frequency was investigated using mire drillings, charcoal in soils and dendrochronology. In the surrounding of the Karwendel, Wetterstein and Mieminger Mountains we have identified c. 400 forest fires to date. The earliest detected fire dates to more than 2900 years; the largest one (in 1705) affected an area of several thousand hectares. Approximately 90% of the fires are man-made (negligence, arson, railway) which explains the concentration on the south-exposed slopes of the densely populated Inn valley. Most of the larger fires take place in the altitudinal belt between 1400 and 1900 m a.s.l.; apart from very few exceptions, they are restricted to southerly orientations. Locally, mean recurrence intervals of 200-300 years occur which is similar to e.g. boreal forests in Canada. We observed a strong seasonality with 40% of the fires occurring in spring and 30% in summer. There is a weak correlation with the weather conditions in the one or two weeks before the fire with dry periods promoting wildfire ignition and burnt area size; however, there are many exceptions from the rule. The 1940ies stands out for more than twice as much fires than in all other decades which is both due to climatic and anthropogenic causes. Today, there is an apparent trend towards more frequent and smaller fires. The frequency is biased by the multitude of available documentation today (e.g. websites of fire brigades), while the decreasing size

Using rainwater harvesting techniques for firefighting in forest plantations

Science.gov (United States)

P. Garcia-Chevesich; R. Valdes-Pineda; D. Neary; R. Pizarro

2015-01-01

Fire is a natural component of forest ecosystems in parts of North America, South America, Europe, Australia, Africa and the Mediterranean region. These fires are usually uncontrolled wildfires in areas of ignitable vegetation but can also be prescribed fires set for vegetation management purposes. Wildfires are commonly characterised based on cause of ignition,...

Polishing the prism: improving wildfire mitigation planning by coupling landscape and social dimensions

Science.gov (United States)

Geoffrey Koch; Alan Ager; Jeff Kline; Paige Fischer

2016-01-01

Effectively addressing wildfire risk to communities on large multi-owner landscapes requires an understanding of the biophysical factors that influence risk, such as fuel loads, topography, and weather, and social factors such as the capacity and willingness for communities to engage in fire-mitigation activities. Biophysical and social processes often are disconnected...

Dual coil ignition system

Energy Technology Data Exchange (ETDEWEB)

Huberts, Garlan J.; Qu, Qiuping; Czekala, Michael Damian

2017-03-28

A dual coil ignition system is provided. The dual coil ignition system includes a first inductive ignition coil including a first primary winding and a first secondary winding, and a second inductive ignition coil including a second primary winding and a second secondary winding, the second secondary winding connected in series to the first secondary winding. The dual coil ignition system further includes a diode network including a first diode and a second diode connected between the first secondary winding and the second secondary winding.

The hidden cost of wildfires: Economic valuation of health effects of wildfire smoke exposure in Southern California

Science.gov (United States)

Richardson, L.A.; Champ, P.A.; Loomis, J.B.

2012-01-01

There is a growing concern that human health impacts from exposure to wildfire smoke are ignored in estimates of monetized damages from wildfires. Current research highlights the need for better data collection and analysis of these impacts. Using unique primary data, this paper quantifies the economic cost of health effects from the largest wildfire in Los Angeles County's modern history. A cost of illness estimate is $9.50 per exposed person per day. However, theory and empirical research consistently find that this measure largely underestimates the true economic cost of health effects from exposure to a pollutant in that it ignores the cost of defensive actions taken as well as disutility. For the first time, the defensive behavior method is applied to calculate the willingness to pay for a reduction in one wildfire smoke induced symptom day, which is estimated to be $84.42 per exposed person per day. ?? 2011.

Ignition delay times of Gasoline Distillation Cuts measured with Ignition Quality Tester

KAUST Repository

Naser, Nimal

2017-04-21

Tailoring fuel properties to maximize the efficiency of internal combustion engines is a way towards achieving cleaner combustion systems. In this work, the ignition properties of various gasoline fuel distillation cuts are analyzed to better understand fuel properties of the full boiling range fuel. An advanced distillation column (ADC) provides a more realistic representation of volatility characteristics, which can be modeled using equilibrium thermodynamic methods. The temperature reported is that of the liquid, as opposed to the vapor temperature in conventional ASTM D86 distillation standard. Various FACE (fuels for advanced combustion engines) gasolines were distilled and various cuts were obtained. The separated fractions were then tested in an ignition quality tester (IQT) to see the effect of chemical composition of different fractions on their ignition delay time. Fuels with lower aromatic content showed decreasing ignition delay time with increasing boiling point (i.e., molecular weight). However, fuels with higher aromatic content showed an initial decrease in ignition delay time with increasing boiling point, followed by drastic increase in ignition delay time due to fractions containing aromatics. This study also provides an understanding on contribution of different fractions to the ignition delay time of the fuel, which provides insights into fuel stratification utilized in gasoline compression ignition (GCI) engines to tailor heat release rates.

Best management practices for creating a community wildfire protection plan

Science.gov (United States)

Pamela J. Jakes; Christine Esposito; Sam Burns; Antony S. Cheng; Kristen C. Nelson; Victoria E. Sturtevant; Daniel R. Williams

2012-01-01

A community wildfire protection plan (CWPP) is a means of bringing local solutions to wildland fire management. In developing and implementing CWPPs, communities assume a leadership role in reducing wildfi re risk on federal and nonfederal land. In this publication, we identify best management practices for CWPP development and implementation based on the experiences...

Fire ignition during laser surgery in pet rodents

Directory of Open Access Journals (Sweden)

Collarile Tommaso

2012-09-01

Full Text Available Abstract Background Laser surgery is an attractive alternative to other means of section device in terms of tissue inflammation and interaction, which has been extensively used in human and veterinary medicine. Although accidental ignition during laser surgeries is sporadically reported in human medical literature, to the authors’ knowledge this is the first report regarding laser-dependent fire ignition during surgery in veterinary medicine. Case presentation Two rodents, a 13-month old, 27-gram, male pet mouse (Mus musculus and a 1-year old, female Russian hamster (Phodopus sungorus, underwent surgical removal of masses with diode laser. During the surgical procedures fires ignited from the face masks. The mouse presented severe burns on the head and both forelimbs, it was hospitalized and approximately 2 months after surgery burns were resolved. The hamster presented severe burns on the face and the proximal regions of the body. At 72 hours from the accident the hamster was euthanized. Conclusion The present report suggests that fire ignition is a potential life-threatening complication of laser surgery in non-intubated rodents maintained under volatile anesthesia. High oxygen concentrations, the presence of combustible, and the narrowness of the surgical field with the face mask during laser surgery on rodents are risk factors for fire ignition.

Forecasting European Wildfires Today and in the Future

Science.gov (United States)

Navarro Abellan, Maria; Porras Alegre, Ignasi; María Sole, Josep; Gálvez, Pedro; Bielski, Conrad; Nurmi, Pertti

2017-04-01

probabilistic output of the FWI for different regions in Europe. This work will improve the currently available information to various wildfire information users such as fire departments, the civil protection, local authorities, etc., where accurate and reliable information in extreme weather situations are vital for improving planning and risk management.

Fuels planning: science synthesis and integration; environmental consequences fact sheet 03: structure fires in the wildland-urban interface

Science.gov (United States)

Steve Sutherland

2004-01-01

National Fire Protection Association (NFPA) data indicate that wildfires destroyed approximately 9,000 homes between 1985 and 1994 in the United States. The loss of homes to wildfire has had a significant impact on Federal fire policy. This fact sheet discusses the causes of home ignitions in the wildland-urban interface, home ignition zones, how to reduce home...

Human influence on the abundance and connectivity of high-risk fuels in mixed forests of northern Wisconsin, USA

Science.gov (United States)

Brian R. Sturtevant; Patrick A. Zoller; Eric J. Gustafson; David T. Cleland

2004-01-01

Though fire is considered a "natural" disturbance, humans heavily influence modern wildfire regimes. Humans influence fires both directly, by igniting and suppressing fires, and indirectly, by either altering vegetation, climate, or both. We used the LANDIS disturbance and succession model to compare the relative importance of a direct human influence (...

Human influence on the abundance and connectivity of high-risk fuels in mixed forests of northern Wisconsin, USA

Science.gov (United States)

Brian R. Sturtevant; Patrick A. Zollner; Eric J. Gustafson; David T. Cleland

2004-01-01

Though fire is considered a "natural" disturbance, humans heavily influence modern wildfire regimes. Humans influence fires both directly, by igniting and suppressing fires, and indirectly, by either altering vegetation, climate, or both. We used the LANDIS disturbance and succession model to compare the relative importance of a direct human influence...

The Evaluation of a Risk Degree for the Process of a Brown Coal Spontaneous Ignition on Dumps with Using of Modern Numeric Methods

Science.gov (United States)

Klouda, Petr; Moni, Vlastimil; Řehoř, Michal; Blata, Jan; Helebrant, František

2018-06-01

The article is a summary of information about evaluation of a risk degree for a brown coal spontaneous ignition which is realized on the base of a database analysis of information about the development of stative quantities and desorbated gases in the stored bodies of the brown coal. The data were gained from the long term complex measurements which were realized at chosen companies during the coal mining in the previous parts of the project. In the last part of the project, we examined results of temperature models from thermographs with results of gasses and coal samples from the mines. Then, the influence of atmospheric conditions (insolation, water downfall, changes of barometric pressure etc.), the influence of coal mass degradation, the influence of physical and chemical factors, and the influence of other defective factors on the process of the coal spontaneous ignition. The gasmetry was assess with gas in-situ samples and laboratory gas models of indicative gasses for the spontaneous ignition, which were taken from the method of the thermic oxidation with the aim of the correlation finding for an epicentre of temperature within the spontaneous ignition.

Stability of Ignition Transients

OpenAIRE

V.E. Zarko

1991-01-01

The problem of ignition stability arises in the case of the action of intense external heat stimuli when, resulting from the cut-off of solid substance heating, momentary ignition is followed by extinction. Physical pattern of solid propellant ignition is considered and ignition criteria available in the literature are discussed. It is shown that the above mentioned problem amounts to transient burning at a given arbitrary temperature distribution in the condensed phase. A brief survey...

Geospatial Analysis Application to Forecast Wildfire Occurrences in South Carolina

Directory of Open Access Journals (Sweden)

Stephen L. Sperry

2012-05-01

Full Text Available Wildfire occurrence and intensity have increased over the last few decades and, at times, have been national news. Wildfire occurrence is somewhat predictable based on physical factors like meteorological conditions, fuel loads, and vegetation dynamics. Socioeconomic factors have been not been widely used in wildfire occurrence models. We used a geospatial (or geographical information system analysis approach to identify socioeconomic variables that contribute to wildfire occurrence. Key variables considered were population change, population density, poverty rate, educational level, geographic mobility, and road density (transportation network. Hot spot analysis was the primary research tool. Wildfire occurrence seemed to be positively related to low population densities, low levels of population change, high poverty rate, low educational attainment level, and low road density. Obviously, some of these variables are correlated and this is a complex problem. However, socioeconomic variables appeared to contribute to wildfire occurrence and should be considered in development of wildfire occurrence forecasting models.

Ignition probabilities for Compact Ignition Tokamak designs

International Nuclear Information System (INIS)

Stotler, D.P.; Goldston, R.J.

1989-09-01

A global power balance code employing Monte Carlo techniques had been developed to study the ''probability of ignition'' and has been applied to several different configurations of the Compact Ignition Tokamak (CIT). Probability distributions for the critical physics parameters in the code were estimated using existing experimental data. This included a statistical evaluation of the uncertainty in extrapolating the energy confinement time. A substantial probability of ignition is predicted for CIT if peaked density profiles can be achieved or if one of the two higher plasma current configurations is employed. In other cases, values of the energy multiplication factor Q of order 10 are generally obtained. The Ignitor-U and ARIES designs are also examined briefly. Comparisons of our empirically based confinement assumptions with two theory-based transport models yield conflicting results. 41 refs., 11 figs

Hydrometeorological conditions preceding wildfire, and the subsequent burning of a fen watershed in Fort McMurray, Alberta, Canada

Science.gov (United States)

Elmes, Matthew C.; Thompson, Dan K.; Sherwood, James H.; Price, Jonathan S.

2018-01-01

The destructive nature of the ˜ 590 000 ha Horse river wildfire in the Western Boreal Plain (WBP), northern Alberta, in May of 2016 motivated the investigation of the hydrometeorological conditions that preceded the fire. Historical climate and field hydrometeorological data from a moderate-rich fen watershed were used to (a) identify whether the spring 2016 conditions were outside the range of natural variability for WBP climate cycles, (b) explain the observed patterns in burn severity across the watershed, and (c) identify whether fall and winter moisture signals observed in peatlands and lowland forests in the region are indicative of wildfire. Field hydrometeorological data from the fen watershed confirmed the presence of cumulative moisture deficits prior to the fire. Hydrogeological investigations highlighted the susceptibility of fen and upland areas to water table and soil moisture decline over rain-free periods (including winter), due to the watershed's reliance on supply from localized flow systems originating in topographic highs. Subtle changes in topographic position led to large changes in groundwater connectivity, leading to greater organic soil consumption by fire in wetland margins and at high elevations. The 2016 spring moisture conditions measured prior to the ignition of the fen watershed were not illustrated well by the Drought Code (DC) when standard overwintering procedures were applied. However, close agreement was found when default assumptions were replaced with measured duff soil moisture recharge and incorporated into the overwintering DC procedure. We conclude that accumulated moisture deficits dating back to the summer of 2015 led to the dry conditions that preceded the fire. The infrequent coinciding of several hydrometeorological conditions, including low autumn soil moisture, a modest snowpack, lack of spring precipitation, and high spring air temperatures and winds, ultimately led to the Horse river wildfire spreading widely and

Towards enhanced risk management: Planning, decision making and monitoring of US wildfire response

Science.gov (United States)

Christopher J. Dunn; David E. Calkin; Matthew P. Thompson

2017-01-01

Wildfire’s economic, ecological and social impacts are on the rise, fostering the realisation that business-as-usual fire management in the United States is not sustainable. Current response strategies may be inefficient and contributing to unnecessary responder exposure to hazardous conditions, but significant knowledge gaps constrain clear and comprehensive...

A tale of two fires: The relative effectiveness of past wildfires in mitigating wildfire behavior and effects

Science.gov (United States)

Robert W. Gray; Susan J. Prichard

2015-01-01

The incidence of large, costly landscape-scale fires in western North America is increasing. To combat these fires, researchers and managers have expressed increased interest in investigating the effectiveness of past, stand-replacing wildfires as bottom-up controls on fire spread and severity. Specifically, how effective are past wildfires in mitigating the behavior...

Power conditioning for the National Ignition Facility

International Nuclear Information System (INIS)

Larson, D.W.; Anderson, R.; Boyes, J.

1994-01-01

A cost-effective, 320-MJ power-conditioning system has been completed for the proposed National Ignition Facility (NIF). The design features include metallized dielectric capacitors, a simple topology, and large (1.6-MJ) module size. Experimental results address the technical risks associated with the design

Wildfire Risk Management on a Landscape with Public and Private Ownership: Who Pays for Protection?

Science.gov (United States)

Busby, Gwenlyn; Albers, Heidi J.

2010-02-01

Wildfire, like many natural hazards, affects large landscapes with many landowners and the risk individual owners face depends on both individual and collective protective actions. In this study, we develop a spatially explicit game theoretic model to examine the strategic interaction between landowners’ hazard mitigation decisions on a landscape with public and private ownership. We find that in areas where ownership is mixed, the private landowner performs too little fuel treatment as they “free ride”—capture benefits without incurring the costs—on public protection, while areas with public land only are under-protected. Our central result is that this pattern of fuel treatment comes at a cost to society because public resources focus in areas with mixed ownership, where local residents capture the benefits, and are not available for publicly managed land areas that create benefits for society at large. We also find that policies that encourage public expenditures in areas with mixed ownership, such as the Healthy Forest Restoration Act of 2003 and public liability for private values, subsidize the residents who choose to locate in the high-risk areas at the cost of lost natural resource benefits for others.

Determination of parameters used to prevent ignition of stored materials and to protect against explosions in food industries.

Science.gov (United States)

Ramírez, Alvaro; García-Torrent, Javier; Aguado, Pedro J

2009-08-30

There are always risks associated with silos when the stored material has been characterized as prone to self-ignition or explosion. Further research focused on the characterization of agricultural materials stored in silos is needed due to the lack of data found in the literature. The aim of this study was to determine the ignitability and explosive parameters of several agricultural products commonly stored in silos in order to assess the risk of ignition and dust explosion. Minimum Ignition Temperature, with dust forming a cloud and deposited in a layer, Lower Explosive Limit, Minimum Ignition Energy, Maximum Explosion Pressure and Maximum Explosion Pressure Rise were determined for seven agricultural materials: icing sugar, maize, wheat and barley grain dust, alfalfa, bread-making wheat and soybean dust. Following characterization, these were found to be prone to producing self-ignition when stored in silos under certain conditions.

Hot Surface Ignition

OpenAIRE

Tursyn, Yerbatyr; Goyal, Vikrant; Benhidjeb-Carayon, Alicia; Simmons, Richard; Meyer, Scott; Gore, Jay P.

2015-01-01

Undesirable hot surface ignition of flammable liquids is one of the hazards in ground and air transportation vehicles, which primarily occurs in the engine compartment. In order to evaluate the safety and sustainability of candidate replacement fuels with respect to hot surface ignition, a baseline low lead fuel (Avgas 100 LL) and four experimental unleaded aviation fuels recommended for reciprocating aviation engines were considered. In addition, hot surface ignition properties of the gas tu...

Harvesting morels after wildfire in Alaska.

Science.gov (United States)

Tricia L. Wurtz; Amy L. Wiita; Nancy S. Weber; David Pilz

2005-01-01

Morels are edible, choice wild mushrooms that sometimes fruit prolifically in the years immediately after an area has been burned by wildfire. Wildfires are common in interior Alaska; an average of 708,700 acres burned each year in interior Alaska between 1961 and 2000, and in major fire years, over 2 million acres burned. We discuss Alaska's boreal forest...

How risk management can prevent future wildfire disasters in the wildland-urban interface

Science.gov (United States)

David E. Calkin; Jack D. Cohen; Mark A. Finney; Matthew P. Thompson

2014-01-01

Recent fire seasons in the western United States are some of the most damaging and costly on record. Wildfires in the wildlandurban interface on the Colorado Front Range, resulting in thousands of homes burned and civilian fatalities, although devastating, are not without historical reference. These fires are consistent with the characteristics of large, damaging,...

Probabilistic assessment of wildfire hazard and municipal watershed exposure

Science.gov (United States)

Joe Scott; Don Helmbrecht; Matthew P. Thompson; David E. Calkin; Kate Marcille

2012-01-01

The occurrence of wildfires within municipal watersheds can result in significant impacts to water quality and ultimately human health and safety. In this paper, we illustrate the application of geospatial analysis and burn probability modeling to assess the exposure of municipal watersheds to wildfire. Our assessment of wildfire exposure consists of two primary...

Fish and fire: Post-wildfire sediment dynamics and implications for the viability of trout populations

Science.gov (United States)

Murphy, B. P.; Czuba, J. A.; Belmont, P.; Budy, P.; Finch, C.

2017-12-01

Episodic events in steep landscapes, such as wildfire and mass wasting, contribute large pulses of sediment to rivers and can significantly alter the quality and connectivity of fish habitat. Understanding where these sediment inputs occur, how they are transported and processed through the watershed, and their geomorphic effect on the river network is critical to predicting the impact on ecological aquatic communities. The Tushar Mountains of southern Utah experienced a severe wildfire in 2010, resulting in numerous debris flows and the extirpation of trout populations. Following many years of habitat and ecological monitoring in the field, we have developed a modeling framework that links post-wildfire debris flows, fluvial sediment routing, and population ecology in order to evaluate the impact and response of trout to wildfire. First, using the Tushar topographic and wildfire parameters, as well as stochastic precipitation generation, we predict the post-wildfire debris flow probabilities and volumes of mainstem tributaries using the Cannon et al. [2010] model. This produces episodic hillslope sediment inputs, which are delivered to a fluvial sediment, river-network routing model (modified from Czuba et al. [2017]). In this updated model, sediment transport dynamics are driven by time-varying discharge associated with the stochastic precipitation generation, include multiple grain sizes (including gravel), use mixed-size transport equations (Wilcock & Crowe [2003]), and incorporate channel slope adjustments with aggradation and degradation. Finally, with the spatially explicit adjustments in channel bed elevation and grain size, we utilize a new population viability analysis (PVA) model to predict the impact and recovery of fish populations in response to these changes in habitat. Our model provides a generalizable framework for linking physical and ecological models and for evaluating the extirpation risk of isolated fish populations throughout the

Progress of impact ignition

International Nuclear Information System (INIS)

Murakami, M.; Nagatomo, H.; Johzaki, T.

2010-11-01

In impact ignition scheme, a portion of the fuel (the impactor) is accelerated to a super-high velocity, compressed by convergence, and collided with a precompressed main fuel. This collision generates shock waves in both the impactor and the main fuel. Since the density of the impactor is generally much lower than that of the main fuel, the pressure balance ensures that the shock-heated temperature of the impactor is significantly higher than that of the main fuel. Hence, the impactor can reach ignition temperature and thus become an igniter. Here we report major new results on recent impact ignition research: (1) A maximum velocity ∼ 1000 km/s has been achieved under the operation of NIKE KrF laser at Naval Research Laboratory (laser wavelength=0.25μm) in the use of a planar target made of plastic and (2) We have performed two-dimensional simulation for burn and ignition to show the feasibility of the impact ignition. (author)

Goals, obstacles and effective strategies of wildfire mitigation programs in the Wildland-Urban Interface

Science.gov (United States)

Margaret A. Reams; Terry K. Haines; Cheryl R. Renner; Michael W. Wascom; Harish Kingre

2005-01-01

The dramatic expansion into the Wildland–Urban Interface (WUI) places property, natural assets, and human life at risk from wildfire destruction. The U.S. National Fire Plan encourages communities to implement laws and outreach programs for pre-fire planning to mitigate the risk to area residents. Starting in 2003, we surveyed the administrators of regulatory and...

Equilibrium ignition for ICF capsules

International Nuclear Information System (INIS)

Lackner, K.S.; Colgate, S.A.; Johnson, N.L.; Kirkpatrick, R.C.; Menikoff, R.; Petschek, A.G.

1993-01-01

There are two fundamentally different approaches to igniting DT fuel in an ICF capsule which can be described as equilibrium and hot spot ignition. In both cases, a capsule which can be thought of as a pusher containing the DT fuel is imploded until the fuel reaches ignition conditions. In comparing high-gain ICF targets using cryogenic DT for a pusher with equilibrium ignition targets using high-Z pushers which contain the radiation. The authors point to the intrinsic advantages of the latter. Equilibrium or volume ignition sacrifices high gain for lower losses, lower ignition temperature, lower implosion velocity and lower sensitivity of the more robust capsule to small fluctuations and asymmetries in the drive system. The reduction in gain is about a factor of 2.5, which is small enough to make the more robust equilibrium ignition an attractive alternative

Progress Towards Ignition on the National Ignition Facility

Science.gov (United States)

Edwards, John

2012-10-01

Since completion of the National Ignition Facility (NIF) construction project in March 2009, a wide variety of diagnostics, facility infrastructure, and experimental platforms have been commissioned in pursuit of generating the conditions necessary to reach thermonuclear ignition in the laboratory via the inertial confinement approach. NIF's capabilities and infrastructure include over 50 X-ray, optical, and nuclear diagnostics systems and the ability to shoot cryogenic DT layered capsules. There are two main approaches to ICF: direct drive in which laser light impinges directly on a capsule containing a solid layer of DT fuel, and indirect drive in which the laser light is first converted to thermal X-rays. To date NIF has been conducting experiments using the indirect drive approach, injecting up to 1.8MJ of ultraviolet light (0.35 micron) into 1 cm scale cylindrical gold or gold-coated uranium, gas-filled hohlraums, to implode 1mm radius plastic capsules containing solid DT fuel layers. In order to achieve ignition conditions the implosion must be precisely controlled. The National Ignition Campaign (NIC), an international effort with the goal of demonstrating thermonuclear burn in the laboratory, is making steady progress toward this. Utilizing precision pulse-shaping experiments in early 2012 the NIC achieve fuel rhoR of approximately 1.2 gm/cm^2 with densities of around 600-800 g/cm^3 along with neutron yields within about a factor of 5 necessary to enter a regime in which alpha particle heating will become important. To achieve these results, experimental platforms were developed to carefully control key attributes of the implosion. This talk will review NIF's capabilities and the progress toward ignition, as well as the physics of ignition targets on NIF and on other facilities. Acknowledgement: this work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Investigating the Impacts of Wildfires on Air Quality in the Western US

Science.gov (United States)

Yates, E. L.; Iraci, L. T.; Singh, H. B.; Ambrosia, V. G.; Clements, C. B.; Gore, W.; Lareau, N.; Quayle, B.; Ryoo, J. M.; Schroeder, W.; Tanaka, T.

2015-12-01

Wildfire emissions are an important source of a wide range of trace gases and particles that can impact local, regional and global air quality, climate forcing, biogeochemical cycles and human health. In the western US, wildfires dominate over prescribed fires. However, limited sampling of wildfire emissions means western US emission estimates rely largely on data from prescribed fires, which may not be a suitable proxy for wildfire emissions. Further, interactions of wildfire emissions with urban pollution, commonly the case with California wildfires, are complex and poorly understood. The Alpha Jet Atmospheric eXperiment (AJAX) sampled a variety of Californian wildfire plumes during 2013 and 2014. In addition to wildfire plumes, flights sample upwind, background conditions allowing for an assessment of enhancement ratios of trace gas species (carbon dioxide, methane and ozone). This paper presents airborne measurements of multiple trace constituents downwind of a variety of Californian wildfires, with a focus on the exceptionally large Yosemite Rim wildfire during summer 2013. During its intense burning phases, the Rim wildfire was sampled by AJAX on 29 August as well as by the NASA DC-8, as part of its SEAC4RS mission, on 26 and 27 August. AJAX revisited the wildfire on 10 September when it had reached its smoldering phase. The more extensive payload of the DC-8 helped to bridge key measurements that were not available as part of the AJAX payload (e. g. carbon monoxide). The emission ratios (ER), emission factors (EF) and combustion efficiency are compared with previous wildfire studies. Integration of AJAX data with other available datasets, such as SEAC4RS, Lidar data from the California State University Mobile Atmospheric Profiling System (CSU-MAPS), MODIS/VIIRS Fire Radiative Power (FRP) and surface ozone and meteorology measurements is explored to assess the impacts of wildfires on downwind air quality including the densely populated California central

New Developments in Wildfire Pollution Forecasting at the Canadian Meteorological Centre

Science.gov (United States)

Pavlovic, Radenko; Chen, Jack; Munoz-Alpizar, Rodrigo; Davignon, Didier; Beaulieu, Paul-Andre; Landry, Hugo; Menard, Sylvain; Gravel, Sylvie; Moran, Michael

2017-04-01

Environment and Climate Change Canada's air quality forecast system with near-real-time wildfire emissions, named FireWork, was developed in 2012 and has been run by the Canadian Meteorological Centre Operations division (CMCO) since 2013. In June 2016 this system was upgraded to operational status and wildfire smoke forecasts for North America are now available to the general public. FireWork's ability to model the transport and diffusion of wildfire smoke plumes has proved to be valuable to regional air quality forecasters and emergency first responders. Some of the most challenging issues with wildfire pollution modelling concern the production of wildfire emission estimates and near-source dispersion within the air quality model. As a consequence, FireWork is undergoing constant development. During the massive Fort McMurray wildfire event in western Canada in May 2016, for example, different wildfire emissions processing approaches and wildfire emissions injection and dispersion schemes were tested within the air quality model. Work on various FireWork components will continue in order to deliver a new operational version of the forecasting system for the 2017 wildfire season. Some of the proposed improvements will be shown in this presentation along with current and planned FireWork post-processing products.

Ignition on the National Ignition Facility: a path towards inertial fusion energy

International Nuclear Information System (INIS)

Moses, Edward I.

2009-01-01

The National Ignition Facility (NIF), the world's largest and most powerful laser system for inertial confinement fusion (ICF) and experiments studying high-energy-density (HED) science, is nearing completion at Lawrence Livermore National Laboratory (LLNL). NIF, a 192-beam Nd-glass laser facility, will produce 1.8 MJ, 500 TW of light at the third-harmonic, ultraviolet light of 351 nm. The NIF project is scheduled for completion in March 2009. Currently, all 192 beams have been operationally qualified and have produced over 4.0 MJ of light at the fundamental wavelength of 1053 nm, making NIF the world's first megajoule laser. The principal goal of NIF is to achieve ignition of a deuterium-tritium (DT) fuel capsule and provide access to HED physics regimes needed for experiments related to national security, fusion energy and for broader scientific applications. The plan is to begin 96-beam symmetric indirect-drive ICF experiments early in FY2009. These first experiments represent the next phase of the National Ignition Campaign (NIC). This national effort to achieve fusion ignition is coordinated through a detailed plan that includes the science, technology and equipment such as diagnostics, cryogenic target manipulator and user optics required for ignition experiments. Participants in this effort include LLNL, General Atomics, Los Alamos National Laboratory, Sandia National Laboratory and the University of Rochester Laboratory for Energetics (LLE). The primary goal for NIC is to have all of the equipment operational and integrated into the facility soon after project completion and to conduct a credible ignition campaign in 2010. When the NIF is complete, the long-sought goal of achieving self-sustaining nuclear fusion and energy gain in the laboratory will be much closer to realization. Successful demonstration of ignition and net energy gain on NIF will be a major step towards demonstrating the feasibility of inertial fusion energy (IFE) and will likely focus

Ignition on the National Ignition Facility: a path towards inertial fusion energy

Science.gov (United States)

Moses, Edward I.

2009-10-01

The National Ignition Facility (NIF), the world's largest and most powerful laser system for inertial confinement fusion (ICF) and experiments studying high-energy-density (HED) science, is nearing completion at Lawrence Livermore National Laboratory (LLNL). NIF, a 192-beam Nd-glass laser facility, will produce 1.8 MJ, 500 TW of light at the third-harmonic, ultraviolet light of 351 nm. The NIF project is scheduled for completion in March 2009. Currently, all 192 beams have been operationally qualified and have produced over 4.0 MJ of light at the fundamental wavelength of 1053 nm, making NIF the world's first megajoule laser. The principal goal of NIF is to achieve ignition of a deuterium-tritium (DT) fuel capsule and provide access to HED physics regimes needed for experiments related to national security, fusion energy and for broader scientific applications. The plan is to begin 96-beam symmetric indirect-drive ICF experiments early in FY2009. These first experiments represent the next phase of the National Ignition Campaign (NIC). This national effort to achieve fusion ignition is coordinated through a detailed plan that includes the science, technology and equipment such as diagnostics, cryogenic target manipulator and user optics required for ignition experiments. Participants in this effort include LLNL, General Atomics, Los Alamos National Laboratory, Sandia National Laboratory and the University of Rochester Laboratory for Energetics (LLE). The primary goal for NIC is to have all of the equipment operational and integrated into the facility soon after project completion and to conduct a credible ignition campaign in 2010. When the NIF is complete, the long-sought goal of achieving self-sustaining nuclear fusion and energy gain in the laboratory will be much closer to realization. Successful demonstration of ignition and net energy gain on NIF will be a major step towards demonstrating the feasibility of inertial fusion energy (IFE) and will likely focus

High frequency ignition arrangement

Energy Technology Data Exchange (ETDEWEB)

Canup, R E

1977-03-03

The invention concerns an HF ignition arrangement for combustion engines with a transistor oscillator. As this oscillator requires a current of 10A, with peak currents up to about 50A, it is not sensible to take this current through the remote ignition switch for switching it on and off. According to the invention the HF high voltage transformer of the ignition is provided with a control winding, which only requires a few milliamps DC and which can therefore be switched via the ignition switch. If the ignition switch is in the 'running' position, then a premagnetising DC current flows through the control winding, which suppresses the oscillation of the oscillator which has current flowing through it, until this current is interrupted by the interruptor contacts controlled by the combustion engine, so that the oscillations of the oscillator start immediately; the oscillator only continues to oscillate during the period during which the interruptor contacts controlled by the machine are open and interrupt the premagnetisation current. The control winding is short circuited in the 'off' position of the ignition switch.

Laser-plasma interaction physics for shock ignition

Directory of Open Access Journals (Sweden)

Goyon C.

2013-11-01

Full Text Available In the shock ignition scheme, the ICF target is first compressed with a long (nanosecond pulse before creating a convergent shock with a short (∼100 ps pulse to ignite thermonuclear reactions. This short pulse is typically (∼2.1015–1016 W/cm2 above LPI (Laser Plasma Instabilities thresholds. The plasma is in a regime where the electron temperature is expected to be very high (2–4 keV and the laser coupling to the plasma is not well understood. Emulating LPI in the corona requires large and hot plasmas produced by high-energy lasers. We conducted experiments on the LIL (Ligne d'Integration Laser, 10 kJ at 3ω and the LULI2000 (0.4 kJ at 2ω facilities, to approach these conditions and study absorption and LPI produced by a high intensity beam in preformed plasmas. After introducing the main risks associated with the short pulse propagation, we present the latest experiment we conducted on LPI in relevant conditions for shock ignition.

Reaching ignition in the tokamak

International Nuclear Information System (INIS)

Furth, H.P.

1985-06-01

This review covers the following areas: (1) the physics of burning plasmas, (2) plasma physics requirements for reaching ignition, (3) design studies for ignition devices, and (4) prospects for an ignition project

Robustness studies of ignition targets for the National Ignition Facility in two dimensions

International Nuclear Information System (INIS)

Clark, Daniel S.; Haan, Steven W.; Salmonson, Jay D.

2008-01-01

Inertial confinement fusion capsules are critically dependent on the integrity of their hot spots to ignite. At the time of ignition, only a certain fractional perturbation of the nominally spherical hot spot boundary can be tolerated and the capsule still achieve ignition. The degree to which the expected hot spot perturbation in any given capsule design is less than this maximum tolerable perturbation is a measure of the ignition margin or robustness of that design. Moreover, since there will inevitably be uncertainties in the initial character and implosion dynamics of any given capsule, all of which can contribute to the eventual hot spot perturbation, quantifying the robustness of that capsule against a range of parameter variations is an important consideration in the capsule design. Here, the robustness of the 300 eV indirect drive target design for the National Ignition Facility [Lindl et al., Phys. Plasmas 11, 339 (2004)] is studied in the parameter space of inner ice roughness, implosion velocity, and capsule scale. A suite of 2000 two-dimensional simulations, run with the radiation hydrodynamics code LASNEX, is used as the data base for the study. For each scale, an ignition region in the two remaining variables is identified and the ignition cliff is mapped. In accordance with the theoretical arguments of Levedahl and Lindl [Nucl. Fusion 37, 165 (1997)] and Kishony and Shvarts [Phys. Plasmas 8, 4925 (2001)], the location of this cliff is fitted to a power law of the capsule implosion velocity and scale. It is found that the cliff can be quite well represented in this power law form, and, using this scaling law, an assessment of the overall (one- and two-dimensional) ignition margin of the design can be made. The effect on the ignition margin of an increase or decrease in the density of the target fill gas is also assessed

Effects of accelerated wildfire on future fire regimes and implications for the United States federal fire policy

Directory of Open Access Journals (Sweden)

Alan A. Ager

2017-12-01

Full Text Available Wildland fire suppression practices in the western United States are being widely scrutinized by policymakers and scientists as costs escalate and large fires increasingly affect social and ecological values. One potential solution is to change current fire suppression tactics to intentionally increase the area burned under conditions when risks are acceptable to managers and fires can be used to achieve long-term restoration goals in fire adapted forests. We conducted experiments with the Envision landscape model to simulate increased levels of wildfire over a 50-year period on a 1.2 million ha landscape in the eastern Cascades of Oregon, USA. We hypothesized that at some level of burned area fuels would limit the growth of new fires, and fire effects on the composition and structure of forests would eventually reduce future fire intensity and severity. We found that doubling current rates of wildfire resulted in detectable feedbacks in area burned and fire intensity. Area burned in a given simulation year was reduced about 18% per unit area burned in the prior five years averaged across all scenarios. The reduction in area burned was accompanied by substantially lower fire severity, and vegetation shifted to open forest and grass-shrub conditions at the expense of old growth habitat. Negative fire feedbacks were slightly moderated by longer-term positive feedbacks, in which the effect of prior area burned diminished during the simulation. We discuss trade-offs between managing fuels with wildfire versus prescribed fire and mechanical fuel treatments from a social and policy standpoint. The study provides a useful modeling framework to consider the potential value of fire feedbacks as part of overall land management strategies to build fire resilient landscapes and reduce wildfire risk to communities in the western U.S. The results are also relevant to prior climate-wildfire studies that did not consider fire feedbacks in projections of future

Exposure to electrocution by automotive ignition system in the work environment of car service employees

OpenAIRE

Bernard Fryśkowski; Dorota Świątek-Fryśkowska

2014-01-01

Automotive ignition system diagnostic procedures involve a specific kind of action due to the presence of high voltage pulses rated of roughly several dozen kilovolts. Therefore, the repairers employed at car service coming into direct contact with electrical equipment of ignition systems are exposed to risk of electric shock. Typically, the electric discharge energy of automotive ignition systems is not high enough to cause fibrillation due to the electric effect on the heart. Nevertheless, ...

Ignition tuning for the National Ignition Campaign

Directory of Open Access Journals (Sweden)

Landen O.

2013-11-01

Full Text Available The overall goal of the indirect-drive inertial confinement fusion [1] tuning campaigns [2] is to maximize the probability of ignition by experimentally correcting for likely residual uncertainties in the implosion and hohlraum physics [3] used in our radiation-hydrodynamic computational models, and by checking for and resolving unexpected shot-to-shot variability in performance [4]. This has been started successfully using a variety of surrogate capsules that set key laser, hohlraum and capsule parameters to maximize ignition capsule implosion velocity, while minimizing fuel adiabat, core shape asymmetry and ablator-fuel mix.

The impact of wildfire on stream fishes in an Atlantic-Mediterranean climate: evidence from an 18-year chronosequence

Directory of Open Access Journals (Sweden)

Monaghan K.A.

2016-01-01

Full Text Available The predicted increase in wildfires associated with climate change poses a risk to freshwater biodiversity that may be exacerbated by river regulation. We studied the effects of wildfire and river management on the fish assemblages of Atlantic-Mediterranean streams in northern Portugal. Employing a chronosquence survey covering an 18-year gradient of impact-recovery from major fire events (ca. 100% catchment burnt, we assessed the ecological response with respect to time since wildfire, interpreting fish assemblages in the context of species traits and characteristics of the river habitat. Non-burnt sites (N = 18; surveyed 4 years previously were compared to burnt sites (N = 14, two of which were part of the non-burnt set, thus providing a Before-After Impact comparison (BAI; N = 2. Across burnt sites richness and abundance were not related to time since wildfire. BAI revealed a contrast in the response of different species that corresponded to descriptive evidence from the chronosequence of burnt sites. As resource specialists, Salmo trutta were negatively impacted by wildfire; Iberian endemic cyprinids, characterized by generalist traits, demonstrated resistance. Habitat structure was a key determinant of wildfire-impact, increasing with channel slope and the degree of channelization. The low abundance of migratory taxa (S. trutta and Anguilla anguilla at burnt sites suggested the importance of fish mobility to post-fire recovery. These data demonstrate that trait profiles and habitat descriptions provide pragmatic information for the management of rivers in fire-susceptible regions and suggest that the rehabilitation of these upland stream habitats might enhance ecological resistance and resilience to catchment wildfire.

The Central Pine Barrens of Long Island, New York - Steps to improve community preparedness for wildfire

Science.gov (United States)

Rachel Hudson; Kristen Nelson; Erika Lang

2004-01-01

This handout provides cooperators and high fire risk communities in the area in and around the central pine barrens of Long Island, New York examples of steps to take to increase wildfire preparedness.

Modelling of hot surface ignition within gas turbines subject to flammable gas in the intake

DEFF Research Database (Denmark)

Pedersen, Lea Duedahl; Nielsen, Kenny Krogh; Yin, Chungen

2017-01-01

Controlling risks associated with fires and explosions from leaks of flammable fluids at oil and gas facilities is paramount to ensuring safe operations. The gas turbine is a significant potential source of ignition; however, the residual risk is still not adequately understood. A model has been...... but decreases with increase in initial mixture temperature and pressure. The model shows a great potential in reliable prediction of the risk of hot surface ignition within gas turbines in the oil and gas industry. In the future, a dedicated experimental study will be performed not only to improve...

Mapping the Relationship Between Wildfire and Poverty

Science.gov (United States)

Kathy Lynn; Wendy Gerlitz

2006-01-01

Wildfires and related government roles and responsibilities for federal wildland management are prominent in our national consciousness because of the increased severity in the last decade of fires on and around public lands. In recent years, laws, strategies, and implementation documents have been issued to direct federal efforts for wildfire prevention, firefighting...

Mercury in terrestrial forested systems with highly elevated mercury deposition in southwestern China: The risk to insects and potential release from wildfires

International Nuclear Information System (INIS)

Zhou, Jun; Wang, Zhangwei; Sun, Ting; Zhang, Huan; Zhang, Xiaoshan

2016-01-01

Forests are considered a pool of mercury in the global mercury cycle. However, few studies have investigated the distribution of mercury in the forested systems in China. Tieshanping forest catchment in southwest China was impacted by mercury emissions from industrial activities and coal combustions. Our work studied mercury content in atmosphere, soil, vegetation and insect with a view to estimating the potential for mercury release during forest fires. Results of the present study showed that total gaseous mercury (TGM) was highly elevated and the annual mean concentration was 3.51 ± 1.39 ng m"−"2. Of the vegetation tissues, the mercury concentration follows the order of leaf/needle > root > bark > branch > bole wood for each species. Total ecosystem mercury pool was 103.5 mg m"−"2 and about 99.4% of the mercury resides in soil layers (0–40 cm). The remaining 0.6% (0.50 mg m"−"2) of mercury was stored in biomass. The large mercury stocks in the forest ecosystem pose a serious threat for large pluses to the atmospheric mercury during potential wildfires and additional ecological stress to forest insect: dung beetles, cicada and longicorn, with mercury concentration of 1983 ± 446, 49 ± 38 and 7 ± 5 ng g"−"1, respectively. Hence, the results obtained in the present study has implications for global estimates of mercury storage in forests, risks to forest insect and potential release to the atmosphere during wildfires. - Highlights: • Mercury in air, soil, biomass and insect were studied at a subtropical forest. • 99.4% of the total ecosystem mercury pools was resided in soil layers. • High mercury pools were large pulses to the atmosphere during potential wildfires. • High mercury deposition in forest pose an ecological stress to insect. - Large mercury pools in forest pose a serious threat for large pluses to the atmospheric mercury during potential wildfires and ecological stress to insect.

In ecoregions across western USA streamflow increases during post-wildfire recovery

Science.gov (United States)

Wine, Michael L.; Cadol, Daniel; Makhnin, Oleg

2018-01-01

Continued growth of the human population on Earth will increase pressure on already stressed terrestrial water resources required for drinking water, agriculture, and industry. This stress demands improved understanding of critical controls on water resource availability, particularly in water-limited regions. Mechanistic predictions of future water resource availability are needed because non-stationary conditions exist in the form of changing climatic conditions, land management paradigms, and ecological disturbance regimes. While historically ecological disturbances have been small and could be neglected relative to climatic effects, evidence is accumulating that ecological disturbances, particularly wildfire, can increase regional water availability. However, wildfire hydrologic impacts are typically estimated locally and at small spatial scales, via disparate measurement methods and analysis techniques, and outside the context of climate change projections. Consequently, the relative importance of climate change driven versus wildfire driven impacts on streamflow remains unknown across the western USA. Here we show that considering wildfire in modeling streamflow significantly improves model predictions. Mixed effects modeling attributed 2%-14% of long-term annual streamflow to wildfire effects. The importance of this wildfire-linked streamflow relative to predicted climate change-induced streamflow reductions ranged from 20%-370% of the streamflow decrease predicted to occur by 2050. The rate of post-wildfire vegetation recovery and the proportion of watershed area burned controlled the wildfire effect. Our results demonstrate that in large areas of the western USA affected by wildfire, regional predictions of future water availability are subject to greater structural uncertainty than previously thought. These results suggest that future streamflows may be underestimated in areas affected by increased prevalence of hydrologically relevant ecological

Estimating wildfire response costs in Alaska's changing climate

Science.gov (United States)

Climate change is altering wildfire activity across Alaska, with increased area burned projected for the future. Changes in wildfire are expected to affect the need for management and suppression resources, however the potential economic implications of these needs have not been ...

Spreading like wildfire

Science.gov (United States)

2017-11-01

The 2017 wildfire season has seen unusually high fire levels in many parts of the world, with extensive and severe fires occurring in Chile, the Mediterranean, Russia, the US, Canada and even Greenland. Is this a sign of things to come?

Review: laser ignition for aerospace propulsion

Directory of Open Access Journals (Sweden)

Steven A. O’Briant

2016-03-01

This paper aims to provide the reader an overview of advanced ignition methods, with an emphasis on laser ignition and its applications to aerospace propulsion. A comprehensive review of advanced ignition systems in aerospace applications is performed. This includes studies on gas turbine applications, ramjet and scramjet systems, and space and rocket applications. A brief overview of ignition and laser ignition phenomena is also provided in earlier sections of the report. Throughout the reading, research papers, which were presented at the 2nd Laser Ignition Conference in April 2014, are mentioned to indicate the vast array of projects that are currently being pursued.

Modelling auto ignition of hydrogen in a jet ignition pre-chamber

Energy Technology Data Exchange (ETDEWEB)

Boretti, Alberto A. [School of Science and Engineering, University of Ballarat, PO Box 663, Ballarat, Victoria 3353 (Australia)

2010-04-15

Spark-less jet ignition pre-chambers are enablers of high efficiencies and load control by quantity of fuel injected when coupled with direct injection of main chamber fuel, thus permitting always lean burn bulk stratified combustion. Towards the end of the compression stroke, a small quantity of hydrogen is injected within the pre-chamber, where it mixes with the air entering from the main chamber. Combustion of the air and fuel mixture then starts within the pre-chamber because of the high temperature of the hot glow plug, and then jets of partially combusted hot gases enter the main chamber igniting there in the bulk, over multiple ignition points, lean stratified mixtures of air and fuel. The paper describes the operation of the spark-less jet ignition pre-chamber coupling CFD and CAE engine simulations to allow component selection and engine performance evaluation. (author)

Wind erosion of soils burned by wildfire

Science.gov (United States)

N. S. Wagenbrenner; M. J. Germino; B. K. Lamb; R. B. Foltz; P. R. Robichaud

2011-01-01

Wind erosion and aeolian transport processes are largely unstudied in the post-wildfire environment, but recent studies have shown that wind erosion can play a major role in burned landscapes. A wind erosion monitoring system was installed immediately following a wildfire in southeastern Idaho, USA to measure wind erosion from the burned area (Figure 1). This paper...

Is Managed Wildfire Protecting Yosemite National Park from Drought?

Science.gov (United States)

Boisrame, G. F. S.; Thompson, S. E.; Stephens, S.; Collins, B.; Kelly, M.; Tague, N.

2016-12-01

Fire suppression in many dry forest types has left a legacy of dense, homogeneous forests. Such landscapes have high water demands and fuel loads, and when burned can result in catastrophically large fires. These characteristics are undesirable in the face of projected warming and drying in the Western US. This project explores the potential of managed wildfire - a forest management strategy in which fires caused by lightning are allowed to burn naturally as long as certain safety parameters are met - to reverse the effects of fire suppression. The Illilouette Creek Basin in Yosemite National Park has experienced 40 years of managed wildfire, reducing forest cover and increasing meadow and shrubland areas. We have collected evidence from field measurements and remote sensing which suggest that managed wildfire increases landscape and hydrologic heterogeneity, and likely improves resilience to disturbances such as fire and drought. Vegetation maps created from aerial photos show an increase in landscape heterogeneity following the introduction of managed wildfire. Soil moisture observations during the drought years of 2013-2016 suggest that transitions from dense forest to shrublands or meadows can increase summer soil moisture. In the winter of 2015-2016, snow depth measurements showed deeper spring snowpacks in burned areas compared to dense forests. Our study provides a unique view of relatively long-term effects of managed wildfire on vegetation change, ecohydrology, and drought resistance. Understanding these effects is increasingly important as the use of managed wildfire becomes more widely accepted, and as the likelihood of both drought and wildfire increases.

Assessing the prospects for achieving double-shell ignition on the National Ignition Facility using vacuum hohlraums

International Nuclear Information System (INIS)

Amendt, Peter; Cerjan, C.; Hamza, A.; Hinkel, D. E.; Milovich, J. L.; Robey, H. F.

2007-01-01

The goal of demonstrating ignition on the National Ignition Facility [J. D. Lindl et al., Phys. Plasmas 11, 339 (2003)] has motivated a revisit of double-shell (DS) targets as a complementary path to the cryogenic baseline approach. Expected benefits of DS ignition targets include noncryogenic deuterium-tritium (DT) fuel preparation, minimal hohlraum-plasma-mediated laser backscatter, low threshold-ignition temperatures (≅4 keV) for relaxed hohlraum x-ray flux asymmetry tolerances, and minimal (two-) shock timing requirements. On the other hand, DS ignition presents several formidable challenges, encompassing room-temperature containment of high-pressure DT (≅790 atm) in the inner shell, strict concentricity requirements on the two shells ( 2 nanoporous aerogels with suspended Cu particles. A prototype demonstration of an ignition DS is planned for 2008, incorporating the needed novel nanomaterials science developments and the required fabrication tolerances for a realistic ignition attempt after 2010

Smouldering peat fires in polluted landscapes and their impact on heavy metal mobilisation

Science.gov (United States)

Clay, Gareth; Rothwell, James; Shuttleworth, Emma

2016-04-01

Whilst wildfires are commonly viewed as a threat confined to Southern Europe, Australia, and North America, recognition of wildfire hazard in the UK has been growing in recent years. UK wildfires often occur on heathland vegetation underlain by peat. These areas can contain industrially-derived legacy pollutants, such as mercury, lead, and arsenic. Ignition of the peat can lead to long-term smouldering fires that are difficult to extinguish, leading to large-scale damage. While work on assessing post-fire damage of peatlands has focussed on carbon and nutrient dynamics, there has been little attention on the release of heavy metals following wildfires. This paper presents initial data from a preliminary study to assess heavy metal release from smouldering peat fires. A homogenised sample of peat from the Peak District National Park, UK was ignited, monitored using thermocouples and an IR camera, and left to smoulder until self-extinguished (~9 hours). Total mass loss was 61%. Samples of pre- and post-burn peat were analysed for their heavy metal concentrations using XRF, ICP-MS, and CVAFS. Sample analysis is ongoing, but initial data shows that there is a substantial (3x) relative enrichment in heavy metal concentrations in post-fire ash. This has important implications for subsequent mobilisation in the aquatic and terrestrial environments, as well as consequences for human health risk through atmospheric redistribution.

Reversed field pinch ignition requirements

International Nuclear Information System (INIS)

Werley, K.A.

1991-01-01

Plasma models are described and used to calculated numerically the transport confinement (nτ E ) requirements and steady state operation points for both the reversed field pinch (RFP) and the tokamak. The models are used to examine the CIT tokamak ignition conditions and the RFP experimental and ignition conditions. Physics differences between RFPs and tokamaks and their consequences for a D-T ignition machine are discussed. Compared with a tokamak, the ignition RFP has many physics advantages, including Ohmic heating to ignition (no need for auxiliary heating systems), higher beta, lower ignition current, less sensitivity of ignition requirements to impurity effects, no hard disruptions (associated with beta or density limits) and successful operation with high radiation fractions (f RAD ∼ 0.95). These physics advantages, coupled with important engineering advantages associated with lower external magnetic field, larger aspect ratios and smaller plasma cross-sections, translate to significant cost reductions for both ignition and reactor applications. The primary drawback of the RFP is the uncertainty that the present scaling will extrapolate to reactor regimes. Devices that are under construction should go a long way toward resolving this scaling uncertainty. The 4 MA ZTH is expected to extend the nτ E transport scaling data by three orders of magnitude above the results of ZT-40M, and, if the present scaling holds, ZTH is expected to achieve a D-T equivalent scientific energy breakeven, Q = 1. A base case RFP ignition point is identified with a plasma current of 8.1 MA and no auxiliary heating. (author). 19 refs, 11 figs, 3 tabs

Wildfire: distributed, Grid-enabled workflow construction and execution

Directory of Open Access Journals (Sweden)

Issac Praveen

2005-03-01

Full Text Available Abstract Background We observe two trends in bioinformatics: (i analyses are increasing in complexity, often requiring several applications to be run as a workflow; and (ii multiple CPU clusters and Grids are available to more scientists. The traditional solution to the problem of running workflows across multiple CPUs required programming, often in a scripting language such as perl. Programming places such solutions beyond the reach of many bioinformatics consumers. Results We present Wildfire, a graphical user interface for constructing and running workflows. Wildfire borrows user interface features from Jemboss and adds a drag-and-drop interface allowing the user to compose EMBOSS (and other programs into workflows. For execution, Wildfire uses GEL, the underlying workflow execution engine, which can exploit available parallelism on multiple CPU machines including Beowulf-class clusters and Grids. Conclusion Wildfire simplifies the tasks of constructing and executing bioinformatics workflows.

Stakeholder understandings of wildfire mitigation: A case of shared and contested meanings

Science.gov (United States)

Joseph G. Champ; Jeffrey J. Brooks; Daniel R. Williams

2012-01-01

This article identifies and compares meanings of wildfire risk mitigation for stakeholders in the Front Range of Colorado, USA. We examine the case of a collaborative partnership sponsored by government agencies and directed to decrease hazardous fuels in interface areas. Data were collected by way of key informant interviews and focus groups. The analysis is guided by...

Tokamak and RFP ignition requirements

International Nuclear Information System (INIS)

Werley, K.A.

1991-01-01

A plasma model is applied to calculate numerically transport- confinement (nτ E ) requirements and steady-state operation tokamak. The CIT tokamak and RFP ignition conditions are examined. Physics differences between RFP and tokamaks, and their consequences for a DT ignition machine, are discussed. The ignition RFP, compared to a tokamak, has many physics advantages, including ohmic heating to ignition (no need for auxiliary heating systems), higher beta, low ignition current, less sensitivity of ignition requirements to impurity effects, no hard disruptions (associated with beta or density limits), and successful operation with high radiation fractions (f RAD ∼ 0.95). These physics advantages, coupled with important engineering advantages associated with lower external magnetic fields, larger aspect ratios, and smaller plasma cross sections translate into significant cost reductions for both ignition and power reactor. The primary drawback of the RFP is the uncertainty that the present confinement scaling will extrapolate to reactor regimes. The 4-MA ZTH was expected to extend the nτ E transport scaling data three order of magnitude above ZT-40M results, and if the present scaling held, to achieve a DT-equivalent scientific energy breakeven, Q=1. A basecase RFP ignition point is identified with a plasma current of 8.1 MA and no auxiliary heating. 16 refs., 4 figs., 1 tab

Ignition of Aluminum Particles and Clouds

Energy Technology Data Exchange (ETDEWEB)

Kuhl, A L; Boiko, V M

2010-04-07

Here we review experimental data and models of the ignition of aluminum (Al) particles and clouds in explosion fields. The review considers: (i) ignition temperatures measured for single Al particles in torch experiments; (ii) thermal explosion models of the ignition of single Al particles; and (iii) the unsteady ignition Al particles clouds in reflected shock environments. These are used to develop an empirical ignition model appropriate for numerical simulations of Al particle combustion in shock dispersed fuel explosions.

Ignition parameters and early flame kernel development of laser-ignited combustible gas mixtures

International Nuclear Information System (INIS)

Kopecek, H.; Wintner, E.; Ruedisser, D.; Iskra, K.; Neger, T.

2002-01-01

Full text: Laser induced breakdown of focused pulsed laser radiation, the subsequent plasma formation and thermalization offers a possibility of ignition of combustible gas mixtures free from electrode interferences, an arbitrary choice of the location within the medium and exact timing regardless of the degree of turbulence. The development and the decreasing costs of solid state laser technologies approach the pay-off for the higher complexity of such an ignition system due to several features unique to laser ignition. The feasability of laser ignition was demonstrated in an 1.5 MW(?) natural gas engine, and several investigations were performed to determine optimal ignition energies, focus shapes and laser wavelengths. The early flame kernel development was investigated by time resolved planar laser induced fluorescence of the OH-radical which occurs predominantly in the flame front. The flame front propagation showed typical features like toroidal initial flame development, flame front return and highly increased flame speed along the laser focus axis. (author)

Real-time estimation of wildfire perimeters from curated crowdsourcing

Science.gov (United States)

Zhong, Xu; Duckham, Matt; Chong, Derek; Tolhurst, Kevin

2016-04-01

Real-time information about the spatial extents of evolving natural disasters, such as wildfire or flood perimeters, can assist both emergency responders and the general public during an emergency. However, authoritative information sources can suffer from bottlenecks and delays, while user-generated social media data usually lacks the necessary structure and trustworthiness for reliable automated processing. This paper describes and evaluates an automated technique for real-time tracking of wildfire perimeters based on publicly available “curated” crowdsourced data about telephone calls to the emergency services. Our technique is based on established data mining tools, and can be adjusted using a small number of intuitive parameters. Experiments using data from the devastating Black Saturday wildfires (2009) in Victoria, Australia, demonstrate the potential for the technique to detect and track wildfire perimeters automatically, in real time, and with moderate accuracy. Accuracy can be further increased through combination with other authoritative demographic and environmental information, such as population density and dynamic wind fields. These results are also independently validated against data from the more recent 2014 Mickleham-Dalrymple wildfires.

Technology and the study of wildfire: Middle school students study the impacts of wildfire

Science.gov (United States)

Fox-Gliessman, D.; Kerski, J.J.

2005-01-01

Various technologies that can assist students in exploring the human and environmental impacts of wildfire and in communicating their findings are discussed. Wildfires occur in many parts of the world, and provide an excellent opportunity for students to study local and global interdisciplinary issues using technology. Prior to the beginning of the field study, students take instructions in both their math and science classes about the distinction and appropriate uses of quantitative and qualitative data. Use of computer programs such as Excel spreadsheets which can contain data, and interaction of research and technology group with students, can help them collect best of the information and in making an accurate report.

A comparative experimental study on engine operating on premixed charge compression ignition and compression ignition mode

Directory of Open Access Journals (Sweden)

Bhiogade Girish E.

2017-01-01

Full Text Available New combustion concepts have been recently developed with the purpose to tackle the problem of high emissions level of traditional direct injection Diesel engines. A good example is the premixed charge compression ignition combustion. A strategy in which early injection is used causing a burning process in which the fuel burns in the premixed condition. In compression ignition engines, soot (particulate matter and NOx emissions are an extremely unsolved issue. Premixed charge compression ignition is one of the most promising solutions that combine the advantages of both spark ignition and compression ignition combustion modes. It gives thermal efficiency close to the compression ignition engines and resolves the associated issues of high NOx and particulate matter, simultaneously. Premixing of air and fuel preparation is the challenging part to achieve premixed charge compression ignition combustion. In the present experimental study a diesel vaporizer is used to achieve premixed charge compression ignition combustion. A vaporized diesel fuel was mixed with the air to form premixed charge and inducted into the cylinder during the intake stroke. Low diesel volatility remains the main obstacle in preparing premixed air-fuel mixture. Exhaust gas re-circulation can be used to control the rate of heat release. The objective of this study is to reduce exhaust emission levels with maintaining thermal efficiency close to compression ignition engine.

Airborne measurements of western U.S. wildfire emissions: Comparison with prescribed burning and air quality implications: Western U.S. Wildfire Emissions

Energy Technology Data Exchange (ETDEWEB)

Liu, Xiaoxi [School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta Georgia USA; Now at Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder Colorado USA; Now at Department of Chemistry, University of Colorado Boulder, Boulder Colorado USA; Huey, L. Gregory [School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta Georgia USA; Yokelson, Robert J. [Department of Chemistry, University of Montana, Missoula Montana USA; Selimovic, Vanessa [Department of Chemistry, University of Montana, Missoula Montana USA; Simpson, Isobel J. [Department of Chemistry, University of California, Irvine California USA; Müller, Markus [Department of Chemistry, University of Montana, Missoula Montana USA; Institute for Ion Physics and Applied Physics, University of Innsbruck, Innsbruck Austria; Jimenez, Jose L. [Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder Colorado USA; Department of Chemistry, University of Colorado Boulder, Boulder Colorado USA; Campuzano-Jost, Pedro [Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder Colorado USA; Department of Chemistry, University of Colorado Boulder, Boulder Colorado USA; Beyersdorf, Andreas J. [NASA Langley Research Center, Hampton Virginia USA; Now at Department of Chemistry, California State University, San Bernardino California USA; Blake, Donald R. [Department of Chemistry, University of California, Irvine California USA; Butterfield, Zachary [Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos New Mexico USA; Now at Department of Atmospheric, Oceanic, and Space Sciences, University of Michigan, Ann Arbor Michigan USA; Choi, Yonghoon [NASA Langley Research Center, Hampton Virginia USA; Science Systems and Applications, Inc., Hampton Virginia USA; Crounse, John D. [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena California USA; Day, Douglas A. [Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder Colorado USA; Department of Chemistry, University of Colorado Boulder, Boulder Colorado USA; Diskin, Glenn S. [NASA Langley Research Center, Hampton Virginia USA; Dubey, Manvendra K. [Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos New Mexico USA; Fortner, Edward [Center for Aerosol and Cloud Chemistry, Aerodyne Research Inc., Billerica Massachusetts USA; Hanisco, Thomas F. [Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center, Greenbelt Maryland USA; Hu, Weiwei [Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder Colorado USA; Department of Chemistry, University of Colorado Boulder, Boulder Colorado USA; King, Laura E. [School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta Georgia USA; Kleinman, Lawrence [Environmental and Climate Sciences Department, Brookhaven National Laboratory, Upton New York USA; Meinardi, Simone [Department of Chemistry, University of California, Irvine California USA; Mikoviny, Tomas [Department of Chemistry, University of Oslo, Oslo Norway; Onasch, Timothy B. [Center for Aerosol and Cloud Chemistry, Aerodyne Research Inc., Billerica Massachusetts USA; Palm, Brett B. [Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder Colorado USA; Department of Chemistry, University of Colorado Boulder, Boulder Colorado USA; Peischl, Jeff [Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder Colorado USA; Earth System Research Laboratory, National Oceanic and Atmospheric Administration, Boulder Colorado USA; Pollack, Ilana B. [Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder Colorado USA; Earth System Research Laboratory, National Oceanic and Atmospheric Administration, Boulder Colorado USA; Now at Department of Atmospheric Science, Colorado State University, Fort Collins Colorado USA; Ryerson, Thomas B. [Earth System Research Laboratory, National Oceanic and Atmospheric Administration, Boulder Colorado USA; Sachse, Glen W. [NASA Langley Research Center, Hampton Virginia USA; Sedlacek, Arthur J. [Environmental and Climate Sciences Department, Brookhaven National Laboratory, Upton New York USA; Shilling, John E. [Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA; Springston, Stephen [Environmental and Climate Sciences Department, Brookhaven National Laboratory, Upton New York USA; St. Clair, Jason M. [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena California USA; Now at Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center, Greenbelt Maryland USA; Now at Joint Center for Earth Systems Technology, University of Maryland, Baltimore County, Baltimore Maryland USA; Tanner, David J. [School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta Georgia USA; Teng, Alexander P. [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena California USA; Wennberg, Paul O. [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena California USA; Division of Engineering and Applied Science, California Institute of Technology, Pasadena California USA; Wisthaler, Armin [Institute for Ion Physics and Applied Physics, University of Innsbruck, Innsbruck Austria; Department of Chemistry, University of Oslo, Oslo Norway; Wolfe, Glenn M. [Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center, Greenbelt Maryland USA; Joint Center for Earth Systems Technology, University of Maryland, Baltimore County, Baltimore Maryland USA

2017-06-14

Wildfires emit significant amounts of pollutants that degrade air quality. Plumes from three wildfires in the western U.S. were measured from aircraft during the Studies of Emissions and Atmospheric Composition, Clouds, and Climate Coupling by Regional Surveys (SEAC4RS) and the Biomass Burning Observation Project (BBOP), both in summer 2013. This study reports an extensive set of emission factors (EFs) for over 80 gases and 5 components of submicron particulate matter (PM1) from these temperate wildfires. These include rarely, or never before, measured oxygenated volatile organic compounds and multifunctional organic nitrates. The observed EFs are compared with previous measurements of temperate wildfires, boreal forest fires, and temperate prescribed fires. The wildfires emitted high amounts of PM1 (with organic aerosol (OA) dominating the mass) with an average EF that is more than two times the EFs for prescribed fires. The measured EFs were used to estimate the annual wildfire emissions of carbon monoxide, nitrogen oxides, total nonmethane organic compounds, and PM1 from 11 western U.S. states. The estimated gas emissions are generally comparable with the 2011 National Emissions Inventory (NEI). However, our PM1 emission estimate (1530 ± 570 Gg yr-1) is over three times that of the NEI PM2.5 estimate and is also higher than the PM2.5 emitted from all other sources in these states in the NEI. This study indicates that the source of OA from BB in the western states is significantly underestimated. In addition, our results indicate prescribed burning may be an effective method to reduce fine particle emissions.

Federal Wildfire Activities. Current Strategy and Issues Needing Attention

National Research Council Canada - National Science Library

1999-01-01

Concerned about the rising costs of preparing for and controlling wildfires, you asked us to provide information on how the Forest Service and the Bureau of Land Management manage their wildfire programs...

Development of multi-year land cover data to assess wildfire impacts to coastal watersheds and the nearshore environment

Science.gov (United States)

Morrison, Katherine D.

In the Mediterranean ecosystems of coastal California, wildfire is a common disturbance that can significantly alter vegetation in watersheds that transport sediment and nutrients to the adjacent nearshore oceanic environment. We assess the impact of two wildfires that burned in 2008 on land cover and to the nearshore environment along the Big Sur coast in central California. We created a multi-year land cover dataset to assess changes to coastal watersheds as a result of fire. This land cover dataset was then used to model changes in nonpoint source pollutants transported to the nearshore environment. Results indicate post-fire increases in percent export compared to pre-fire years and also link wildfire severity to the specific land cover changes that subsequently increase exports of pollutants and sediment to the nearshore environment. This approach is a replicable across watersheds and also provides a framework for including the nearshore environment as a value at risk terrestrial land management revolving around wildfire, including suppression, thinning, and other activities that change land cover at a landscape scale.

Design of ignition targets for the National Ignition Facility

International Nuclear Information System (INIS)

Haan, S.W.; Dittrich, T.R.; Marinak, M.M.; Hinkel, D.E.

1999-01-01

This is a brief update on the work being done to design ignition targets for the National Ignition Facility. Updates are presented on three areas of current activity : improvements in modeling, work on a variety of targets spanning the parameter space of possible ignition targets ; and the setting of specifications for target fabrication and diagnostics. Highlights of recent activity include : a simulation of the Rayleigh-Taylor instability growth on an imploding capsule, done in 3D on a 72degree by 72degree wedge, with enough zones to resolve modes out to 100 ; and designs of targets at 250eV and 350eV, as well as the baseline 300 eV ; and variation of the central DT gas density, which influences both the Rayleigh-Taylor growth and the smoothness of the DT ice layer

A novel three-axis cylindrical hohlraum designed for inertial confinement fusion ignition

Science.gov (United States)

Kuang, Longyu; Li, Hang; Jing, Longfei; Lin, Zhiwei; Zhang, Lu; Li, Liling; Ding, Yongkun; Jiang, Shaoen; Liu, Jie; Zheng, Jian

2016-10-01

A novel ignition hohlraum for indirect-drive inertial confinement fusion is proposed, which is named three-axis cylindrical hohlraum (TACH). TACH is a kind of 6 laser entrance holes (LEHs) hohlraum, which is orthogonally jointed of three cylindrical hohlraums. Laser beams are injected through every entrance hole with the same incident angle of 55°. A view-factor simulation result shows that the time-varying drive asymmetry of TACH is less than 1.0% in the whole drive pulse period without any supplementary technology. Coupling efficiency of TACH is close to that of 6 LEHs spherical hohlraum with corresponding size. Its plasma-filling time is close to that of typical cylindrical ignition hohlraum. Its laser plasma interaction has as low backscattering as the outer cone of the cylindrical ignition hohlraum. Therefore, TACH combines most advantages of various hohlraums and has little predictable risk, providing an important competitive candidate for ignition hohlraum.

Repeated wildfires alter forest recovery of mixed-conifer ecosystems.

Science.gov (United States)

Stevens-Rumann, Camille; Morgan, Penelope

2016-09-01

Most models project warmer and drier climates that will contribute to larger and more frequent wildfires. However, it remains unknown how repeated wildfires alter post-fire successional patterns and forest structure. Here, we test the hypothesis that the number of wildfires, as well as the order and severity of wildfire events interact to alter forest structure and vegetation recovery and implications for vegetation management. In 2014, we examined forest structure, composition, and tree regeneration in stands that burned 1-18 yr before a subsequent 2007 wildfire. Three important findings emerged: (1) Repeatedly burned forests had 15% less woody surface fuels and 31% lower tree seedling densities compared with forests that only experienced one recent wildfire. These repeatedly burned areas are recovering differently than sites burned once, which may lead to alternative ecosystem structure. (2) Order of burn severity (high followed by low severity compared with low followed by high severity) did influence forest characteristics. When low burn severity followed high, forests had 60% lower canopy closure and total basal area with 92% fewer tree seedlings than when high burn severity followed low. (3) Time between fires had no effect on most variables measured following the second fire except large woody fuels, canopy closure and tree seedling density. We conclude that repeatedly burned areas meet many vegetation management objectives of reduced fuel loads and moderate tree seedling densities. These differences in forest structure, composition, and tree regeneration have implications not only for the trajectories of these forests, but may reduce fire intensity and burn severity of subsequent wildfires and may be used in conjunction with future fire suppression tactics. © 2016 by the Ecological Society of America.

[Exposure to electrocution by automotive ignition system in the work environment of car service employees].

Science.gov (United States)

Fryśkowski, Bernard; Swiatek-Fryśkowska, Dorota

2014-01-01

Automotive ignition system diagnostic procedures involve a specific kind of action due to the presence of high voltage pulses rated of roughly several dozen kilovolts. Therefore, the repairers employed at car service coming into direct contact with electrical equipment of ignition systems are exposed to risk of electric shock. Typically, the electric discharge energy of automotive ignition systems is not high enough to cause fibrillation due to the electric effect on the heart. Nevertheless, there are drivers and car service employees who use electronic cardiac pacemakers susceptible to high voltage pulses. The influence of high-voltage ignition systems on the human body, especially in case of electric injury, has not been comprehensively elucidated. Therefore, relatively few scientific papers address this problem. The aim of this paper is to consider the electrical injury danger from automotive ignition systems, especially in people suffering from cardiac diseases. Some examples of the methods to reduce electric shock probability during diagnostic procedures of spark-ignition combustion engines are presented and discussed.

Wildfire ash: its production and hydro-eco-geomorphic effects in forested landscapes

Science.gov (United States)

Doerr, S. H.; Bodi, M.; Santin, C.; Balfour, V.; Woods, S.; Mataix-Solera, J.; Cerda, A.; Shakesby, R.

2012-12-01

Fire, whether ignited naturally or by humans, is one of the most important disturbance agents in many of the world's forested ecosystems. Amongst its direct consequences is the deposition of a range of solid and largely powdery residues on the ground consisting of charred organic material including charcoal and residual mineral material. This fragile 'ash' layer can be removed in large quantities from hillslopes within days by wind or water erosion, with the latter facilitating its transfer to the hydrological system. Probably as a result of its ephemeral nature and not being soil, vegetation or litter, ash has seen limited attention in studies on hydrological impacts of wildfire. Those few studies available show that ash can substantially affect the hydrological system. When present on hillslopes as a water-absorbent layer, it can reduce surface runoff, protect soil against rainsplash erosion, and its leachates can reportedly reduce soil erodibility by promoting flocculation of dispersed clays. In contrast, however, ash can also increase surface runoff by blocking soil pores or by forming a crust. Furthermore, ash is thought capable of promoting debris flows. Its net effect probably depends on the nature of the ash and soil including their respective water repellency levels, the pore size distribution of the soil, and general terrain and rainfall characteristics. Being very mobile, ash can be the source of substantial organic and inorganic sediment inputs, and of solute influxes into the fluvial system. These can affect water quality sometimes with detrimental effects on aquatic organisms and domestic water supply. This presentation aims to provide an overview of the current knowledge base regarding the production and potential effects of wildfire ash on the hydrological system in and beyond forested landscapes..The late Scott Woods examining a thick ash layer following a severe fire in a conifer forest. Montana, USA.

Risk and Cooperation: Managing Hazardous Fuel in Mixed Ownership Landscapes

Science.gov (United States)

Fischer, A. Paige; Charnley, Susan

2012-06-01

Managing natural processes at the landscape scale to promote forest health is important, especially in the case of wildfire, where the ability of a landowner to protect his or her individual parcel is constrained by conditions on neighboring ownerships. However, management at a landscape scale is also challenging because it requires cooperation on plans and actions that cross ownership boundaries. Cooperation depends on people's beliefs and norms about reciprocity and perceptions of the risks and benefits of interacting with others. Using logistic regression tests on mail survey data and qualitative analysis of interviews with landowners, we examined the relationship between perceived wildfire risk and cooperation in the management of hazardous fuel by nonindustrial private forest (NIPF) owners in fire-prone landscapes of eastern Oregon. We found that NIPF owners who perceived a risk of wildfire to their properties, and perceived that conditions on nearby public forestlands contributed to this risk, were more likely to have cooperated with public agencies in the past to reduce fire risk than owners who did not perceive a risk of wildfire to their properties. Wildfire risk perception was not associated with past cooperation among NIPF owners. The greater social barriers to private-private cooperation than to private-public cooperation, and perceptions of more hazardous conditions on public compared with private forestlands may explain this difference. Owners expressed a strong willingness to cooperate with others in future cross-boundary efforts to reduce fire risk, however. We explore barriers to cooperative forest management across ownerships, and identify models of cooperation that hold potential for future collective action to reduce wildfire risk.

Wildfire, wildlands, and people: understanding and preparing for wildfire in the wildland-urban interface - a Forests on the Edge report

Science.gov (United States)

S. M. Stein; J. Menakis; M. A. Carr; S. J. Comas; S. I. Stewart; H. Cleveland; L. Bramwell; V. C. Radeloff

2013-01-01

Fire has historically played a fundamental ecological role in many of America's wildland areas. However, the rising number of homes in the wildland-urban interface (WUI), associated impacts on lives and property from wildfire, and escalating costs of wildfire management have led to an urgent need for communities to become "fire-adapted." We present maps...

Analysis of cyclic variations during mode switching between spark ignition and controlled auto-ignition combustion operations

OpenAIRE

Chen, T; Zhao, H; Xie, H; He, B

2014-01-01

© IMechE 2014. Controlled auto-ignition, also known as homogeneous charge compression ignition, has been the subject of extensive research because of their ability to provide simultaneous reductions in fuel consumption and NOx emissions from a gasoline engine. However, due to its limited operation range, switching between controlled auto-ignition and spark ignition combustion is needed to cover the complete operating range of a gasoline engine for passenger car applications. Previous research...

The National Ignition Facility. The path to ignition and inertial fusion energy

International Nuclear Information System (INIS)

Eric Storm

2010-01-01

Complete text of publication follows. The National Ignition Facility (NIF), the world's largest and most energetic laser system built for studying inertial confinement fusion (ICF) and high-energy-density (HED) science, is now operational at Lawrence Livermore National Laboratory (LLNL). NIF's 192 beams are capable of producing 1.8 MJ and 500 TW of ultraviolet light and are configured to create pressures as high as 100 GB, matter temperatures approaching 10 9 and densities over 1000 g/cm 3 . With these capabis70lities, the NIF will enable exploring scientific problems in strategic defense, basic science and fusion energy. One of the early NIF campaigns is focusing on demonstrating laboratory-scale thermonuclear ignition and burn to produce net fusion energy gains of 10-20 with 1.2 to 1.4 MJ of 0.35 μm light. NIF ignition experiments began late in FY2009 as part of the National Ignition Campaign (NIC). Participants of NIC include LLNL, General Atomics, Los Alamos National Laboratory, Sandia National Laboratory, and the University of Rochester Laboratory for Energetics (LLE) as well as variety of national and international collaborators. The results from these initial experiments show great promise for the relatively near-term achievement of ignition. Capsule implosion experiments at energies up to 1.2 MJ have demonstrated laser energetics, radiation temperatures, and symmetry control that scale to ignition conditions. Of particular importance is the demonstration of peak hohlraum temperatures near 300 eV with low overall backscatter less than 10%. Cryogenic target capability and additional diagnostics are being installed in preparation for layered target deuterium-tritium implosions to be conducted later in 2010. The goal for NIC is to demonstrate a predictable fusion experimental platform by the end of 2012. Successful demonstration of ignition and net energy gain on NIF will be a major step towards demonstrating the feasibility of Inertial Fusion Energy (IFE) and

A Comparative Study of Cycle Variability of Laser Plug Ignition vs Classical Spark Plug Ignition in Combustion Engines

Science.gov (United States)

Done, Bogdan

2017-10-01

Over the past 30 years numerous studies and laboratory experiments have researched the use of laser energy to ignite gas and fuel-air mixtures. The actual implementation of this laser application has still to be fully achieved in a commercial automotive application. Laser Plug Ignition as a replacement for Spark Plug Ignition in the internal combustion engines of automotive vehicles, offers several potential benefits such as extending lean burn capability, reducing the cyclic variability between combustion cycles and decreasing the total amount of ignition costs, and implicitly weight and energy requirements. The paper presents preliminary results of cycle variability study carried on a SI Engine equipped with laser Plug Ignition system. Versus classic ignition system, the use of the laser Plug Ignition system assures the reduction of the combustion process variability, reflected in the lower values of the coefficient of variability evaluated for indicated mean effective pressure, maximum pressure, maximum pressure angle and maximum pressure rise rate. The laser plug ignition system was mounted on an experimental spark ignition engine and tested at the regime of 90% load and 2800 rev/min, at dosage of λ=1.1. Compared to conventional spark plug, laser ignition assures the efficiency at lean dosage.

Effect of flow velocity and temperature on ignition characteristics in laser ignition of natural gas and air mixtures

Science.gov (United States)

Griffiths, J.; Riley, M. J. W.; Borman, A.; Dowding, C.; Kirk, A.; Bickerton, R.

2015-03-01

Laser induced spark ignition offers the potential for greater reliability and consistency in ignition of lean air/fuel mixtures. This increased reliability is essential for the application of gas turbines as primary or secondary reserve energy sources in smart grid systems, enabling the integration of renewable energy sources whose output is prone to fluctuation over time. This work details a study into the effect of flow velocity and temperature on minimum ignition energies in laser-induced spark ignition in an atmospheric combustion test rig, representative of a sub 15 MW industrial gas turbine (Siemens Industrial Turbomachinery Ltd., Lincoln, UK). Determination of minimum ignition energies required for a range of temperatures and flow velocities is essential for establishing an operating window in which laser-induced spark ignition can operate under realistic, engine-like start conditions. Ignition of a natural gas and air mixture at atmospheric pressure was conducted using a laser ignition system utilizing a Q-switched Nd:YAG laser source operating at 532 nm wavelength and 4 ns pulse length. Analysis of the influence of flow velocity and temperature on ignition characteristics is presented in terms of required photon flux density, a useful parameter to consider during the development laser ignition systems.

National database for calculating fuel available to wildfires

Science.gov (United States)

Donald McKenzie; Nancy H.F. French; Roger D. Ottmar

2012-01-01

Wildfires are increasingly emerging as an important component of Earth system models, particularly those that involve emissions from fires and their effects on climate. Currently, there are few resources available for estimating emissions from wildfires in real time, at subcontinental scales, in a spatially consistent manner. Developing subcontinental-scale databases...

Airborne measurements of western U.S. wildfire emissions: Comparison with prescribed burning and air quality implications: Western U.S. Wildfire Emissions

International Nuclear Information System (INIS)

Liu, Xiaoxi; University of Colorado, Boulder, CO; Huey, L. Gregory; Yokelson, Robert J.; Selimovic, Vanessa

2017-01-01

Wildfires emit significant amounts of pollutants that degrade air quality. Plumes from three wildfires in the western U.S. were measured from aircraft during the Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) and the Biomass Burning Observation Project (BBOP), both in summer 2013. This study reports an extensive set of emission factors (EFs) for over 80 gases and 5 components of submicron particulate matter (PM 1 ) from these temperate wildfires. These include rarely, or never before, measured oxygenated volatile organic compounds and multifunctional organic nitrates. The observed EFs are compared with previous measurements of temperate wildfires, boreal forest fires, and temperate prescribed fires. Furthermore, the wildfires emitted high amounts of PM 1 (with organic aerosol (OA) dominating the mass) with an average EF that is more than 2 times the EFs for prescribed fires. The measured EFs were used to estimate the annual wildfire emissions of carbon monoxide, nitrogen oxides, total nonmethane organic compounds, and PM 1 from 11 western U.S. states. The estimated gas emissions are generally comparable with the 2011 National Emissions Inventory (NEI). However, our PM 1 emission estimate (1530 ± 570 Gg yr -1 ) is over 3 times that of the NEI PM2.5 estimate and is also higher than the PM2.5 emitted from all other sources in these states in the NEI. This study indicates that the source of OA from biomass burning in the western states is significantly underestimated. Additionally, our results indicate that prescribed burning may be an effective method to reduce fine particle emissions.

Shock ignition of high gain inertial fusion capsules

International Nuclear Information System (INIS)

Schurtz, G.; Ribeyre, X.; Lebel, E.; Casner, A.

2010-01-01

Complete text of publication follows. Inertial Confinement Fusion relies on the compression of small amounts of an equimolar mix of Deuterium and Tritium (DT) up to volumic masses of several hundreds of g/cm 3 . Such high densities are obtained by means of the implosion of a spherical shell made of cryogenic DT fuel. In the conventional scheme a hot spot is formed in the central part of the pellet at the end of the implosion. If the pressure of this hot spot is large enough (several hundreds of Gbars), thermonuclear heating occurs with a characteristic time shorter than the hydrodynamic confinement time and the target self ignites. Since the central hot spot pressure results from the conversion of the shell kinetic energy into thermal energy, the threshold for the ignition of a given mass of DT is a direct function of the implosion velocity. Typical implosion velocities for central self ignition are of the order of 400 km/s. Such high velocities imply both a strong acceleration of the shell and the use of large aspect ration shells in order to optimize the hydrodynamic efficiency of the implosion, at least in direct drive. These two features strongly enhance the risk of shell beak up at time of acceleration under the Rayleigh-Taylor instability. Furthermore the formation of the hot spot may itself the unstable, this reducing its effective mass. High compression may be achieved at much lower velocities, thus reducing the energy budget and enhancing the implosion safety, but the corresponding fuel assembly requires an additional heating in order to reach ignition. This heating may be obtained from a 70-100 kJ laser pulse, delivered in 10-15 ps (Fast Ignition). An alternative idea is to boost up the central pressure of a target imploded at a sub-ignition velocity by means of a convergent strong shock launched at the end of the compression phase. This Shock Ignition (SI) concept has been suggested in 1983 by Scherbakov et al. More recently, R. Betti et al. developed

The evolution of Smokey Bear: Environmental education about wildfire for youth

Science.gov (United States)

Heidi L. Ballard; Emily Evans; Victoria E. Sturtevant; Pamela. Jakes

2012-01-01

Many environmental education programs in the United States educate youth about the prevention of wildfire and its role in ecosystems.We reviewed 50 wildfire education programs for youth (WEY) in the U.S. through an Internet search and interviews with program providers. We investigated whether they reflect current wildfire science, environmental education (EE)...

Two-stage Lagrangian modeling of ignition processes in ignition quality tester and constant volume combustion chambers

KAUST Repository

Alfazazi, Adamu

2016-08-10

The ignition characteristics of isooctane and n-heptane in an ignition quality tester (IQT) were simulated using a two-stage Lagrangian (TSL) model, which is a zero-dimensional (0-D) reactor network method. The TSL model was also used to simulate the ignition delay of n-dodecane and n-heptane in a constant volume combustion chamber (CVCC), which is archived in the engine combustion network (ECN) library (http://www.ca.sandia.gov/ecn). A detailed chemical kinetic model for gasoline surrogates from the Lawrence Livermore National Laboratory (LLNL) was utilized for the simulation of n-heptane and isooctane. Additional simulations were performed using an optimized gasoline surrogate mechanism from RWTH Aachen University. Validations of the simulated data were also performed with experimental results from an IQT at KAUST. For simulation of n-dodecane in the CVCC, two n-dodecane kinetic models from the literature were utilized. The primary aim of this study is to test the ability of TSL to replicate ignition timings in the IQT and the CVCC. The agreement between the model and the experiment is acceptable except for isooctane in the IQT and n-heptane and n-dodecane in the CVCC. The ability of the simulations to replicate observable trends in ignition delay times with regard to changes in ambient temperature and pressure allows the model to provide insights into the reactions contributing towards ignition. Thus, the TSL model was further employed to investigate the physical and chemical processes responsible for controlling the overall ignition under various conditions. The effects of exothermicity, ambient pressure, and ambient oxygen concentration on first stage ignition were also studied. Increasing ambient pressure and oxygen concentration was found to shorten the overall ignition delay time, but does not affect the timing of the first stage ignition. Additionally, the temperature at the end of the first stage ignition was found to increase at higher ambient pressure

Efficient and Equitable Design of Wildfire Mitigation Programs

Science.gov (United States)

Thomas P. Holmes; Karen L. Abt; Robert Huggett; Jeffrey P. Prestemon

2007-01-01

Natural resource economists have addresssed the economic effienciency of expenditures on wildfire mitigation for nearly a century (Gope and Gorte 1979). Beginning with the work of Sparhawk (1925), the theory of efficent wildfire mitigation developed alolng conceptual lines drawn form neoclassical economics. The objective of the traditional least-cost-plus-loss model...

Development and testing of hydrogen ignition devices

International Nuclear Information System (INIS)

Renfro, D.; Smith, L.; Thompson, L.; Clever, R.

1982-01-01

Controlled ignition systems for the mitigation of hydrogen produced during degraded core accidents have been installed recently in several light water reactor (LWR) containments. This paper relates the background of the thermal igniter approach and its application to LWR controlled ignition systems. The process used by the Tennessee Valley Authority (TVA) to select a hydrogen mitigation system in general and an igniter type in particular is described. Descriptions of both the Interim Distributed Ignition System and the Permanent Hydrogen Mitigation System installed by TVA are included as examples. Testing of igniter durability at TVA's Singleton Materials Engineering Laboratory and of igniter performance at Atomic Energy of Canada's Whiteshell Nuclear Research Establishment is presented

Rapid increases and time-lagged declines in amphibian occupancy after wildfire.

Science.gov (United States)

Hossack, Blake R; Lowe, Winsor H; Corn, Paul Stephen

2013-02-01

Climate change is expected to increase the frequency and severity of drought and wildfire. Aquatic and moisture-sensitive species, such as amphibians, may be particularly vulnerable to these modified disturbance regimes because large wildfires often occur during extended droughts and thus may compound environmental threats. However, understanding of the effects of wildfires on amphibians in forests with long fire-return intervals is limited. Numerous stand-replacing wildfires have occurred since 1988 in Glacier National Park (Montana, U.S.A.), where we have conducted long-term monitoring of amphibians. We measured responses of 3 amphibian species to fires of different sizes, severity, and age in a small geographic area with uniform management. We used data from wetlands associated with 6 wildfires that burned between 1988 and 2003 to evaluate whether burn extent and severity and interactions between wildfire and wetland isolation affected the distribution of breeding populations. We measured responses with models that accounted for imperfect detection to estimate occupancy during prefire (0-4 years) and different postfire recovery periods. For the long-toed salamander (Ambystoma macrodactylum) and Columbia spotted frog (Rana luteiventris), occupancy was not affected for 6 years after wildfire. But 7-21 years after wildfire, occupancy for both species decreased ≥ 25% in areas where >50% of the forest within 500 m of wetlands burned. In contrast, occupancy of the boreal toad (Anaxyrus boreas) tripled in the 3 years after low-elevation forests burned. This increase in occupancy was followed by a gradual decline. Our results show that accounting for magnitude of change and time lags is critical to understanding population dynamics of amphibians after large disturbances. Our results also inform understanding of the potential threat of increases in wildfire frequency or severity to amphibians in the region. ©2012 Society for Conservation Biology.

Design risk analysis comparison between low-activation composite and aluminum alloy target chamber for the National Ignition Facility

International Nuclear Information System (INIS)

Streckert, H.H.; Schleicher, R.W.

1997-01-01

The baseline design for the target chamber for the National Ignition Facility (NIF) consists of an aluminum alloy spherical shell. A low-activation composite chamber (e.g., carbon fiber/epoxy) has important advantages such as enhanced environmental and safety characteristics, improved chamber accessibility due to reduced neutron-induced radioactivity, and elimination of the concrete shield. However, it is critical to determine the design and manufacturing risk for the first application. The replacement of such a critical component requires a detailed development risk assessment. A semiquantitative approach to risk assessment has been applied to this problem based on failure modes, effects, and criticality analysis. This analysis consists of a systematic method for organizing the collective judgment of the designers to identify failure modes, estimate probabilities, judge the severity of the consequence, and illustrate risk in a matrix representation. The results of the analyses indicate that the composite chamber has a reasonably high probability of success in the NIF application. The aluminum alloy chamber, however, represents a lower risk, partially based on a more mature technology. 8 refs., 4 figs., 5 tabs

Auto-Ignition and Spray Characteristics of n-Heptane and iso-Octane Fuels in Ignition Quality Tester

KAUST Repository

Jaasim, Mohammed

2018-04-04

Numerical simulations were conducted to systematically assess the effects of different spray models on the ignition delay predictions and compared with experimental measurements obtained at the KAUST ignition quality tester (IQT) facility. The influence of physical properties and chemical kinetics over the ignition delay time is also investigated. The IQT experiments provided the pressure traces as the main observables, which are not sufficient to obtain a detailed understanding of physical (breakup, evaporation) and chemical (reactivity) processes associated with auto-ignition. A three-dimensional computational fluid dynamics (CFD) code, CONVERGE™, was used to capture the detailed fluid/spray dynamics and chemical characteristics within the IQT configuration. The Reynolds-averaged Navier-Stokes (RANS) turbulence with multi-zone chemistry sub-models was adopted with a reduced chemical kinetic mechanism for n-heptane and iso-octane. The emphasis was on the assessment of two common spray breakup models, namely the Kelvin-Helmholtz/Rayleigh-Taylor (KH-RT) and linearized instability sheet atomization (LISA) models, in terms of their influence on auto-ignition predictions. Two spray models resulted in different local mixing, and their influence in the prediction of auto-ignition was investigated. The relative importance of physical ignition delay, characterized by spray evaporation and mixing processes, in the overall ignition behavior for the two different fuels were examined. The results provided an improved understanding of the essential contribution of physical and chemical processes that are critical in describing the IQT auto-ignition event at different pressure and temperature conditions, and allowed a systematic way to distinguish between the physical and chemical ignition delay times.

On the effects of wildfires on precipitation in Southern Africa

Science.gov (United States)

De Sales, Fernando; Okin, Gregory S.; Xue, Yongkang; Dintwe, Kebonye

2018-03-01

This study investigates the impact of wildfire on the climate of Southern Africa. Moderate resolution imaging spectroradiometer derived burned area fraction data was implemented in a set of simulations to assess primarily the role of wildfire-induced surface changes on monthly precipitation. Two post-fire scenarios are examined namely non-recovering and recovering vegetation scenarios. In the former, burned vegetation fraction remains burned until the end of the simulations, whereas in the latter it is allowed to regrow following a recovery period. Control simulations revealed that the model can dependably capture the monthly precipitation and surface temperature averages in Southern Africa thus providing a reasonable basis against which to assess the impacts of wildfire. In general, both wildfire scenarios have a negative impact on springtime precipitation. September and October were the only months with statistically significant precipitation changes. During these months, precipitation in the region decreases by approximately 13 and 9% in the non-recovering vegetation scenario, and by about 10 and 6% in the recovering vegetation wildfire scenario, respectively. The primary cause of precipitation deficit is the decrease in evapotranspiration resulting from a reduction in surface net radiation. Areas impacted by the precipitation reduction includes the Luanda, Kinshasa, and Brazzaville metropolitan areas, The Angolan Highlands, which are the source of the Okavango Rive, and the Okavango Delta region. This study suggests that a probable intensification in wildfire frequency and extent resulting from projected population increase and global warming in Southern Africa could potentially exacerbate the impacts of wildfires in the region's seasonal precipitation.

Assessing wildfire exposure in the Wildland-Urban Interface area of the mountains of central Argentina.

Science.gov (United States)

Argañaraz, J P; Radeloff, V C; Bar-Massada, A; Gavier-Pizarro, G I; Scavuzzo, C M; Bellis, L M

2017-07-01

Wildfires are a major threat to people and property in Wildland Urban Interface (WUI) communities worldwide, but while the patterns of the WUI in North America, Europe and Oceania have been studied before, this is not the case in Latin America. Our goals were to a) map WUI areas in central Argentina, and b) assess wildfire exposure for WUI communities in relation to historic fires, with special emphasis on large fires and estimated burn probability based on an empirical model. We mapped the WUI in the mountains of central Argentina (810,000 ha), after digitizing the location of 276,700 buildings and deriving vegetation maps from satellite imagery. The areas where houses and wildland vegetation intermingle were classified as Intermix WUI (housing density > 6.17 hu/km 2 and wildland vegetation cover > 50%), and the areas where wildland vegetation abuts settlements were classified as Interface WUI (housing density > 6.17 hu/km 2 , wildland vegetation cover planning aimed at reducing wildfire risk in WUI communities. Copyright © 2017 Elsevier Ltd. All rights reserved.

The volume ignition for ICF ignition target

International Nuclear Information System (INIS)

Li, Y. S.; He, X. T.; Yu, M.

1997-01-01

Compared with central model, volume ignition has no hot spot, avoids the mixing at the hot-cold interface, the α-particle escaping, and the high convergence, greatly reduces the sharp demanding for uniformity. In laser indirect driving, from theoretical estimation and computational simulation, we have proved that using a tamper with good heat resistance, the DT fuel can be ignited in LTE at ∼3 KeV and then evolves to the non-LTE ignition at >5 KeV. In this case, 1 MJ radiation energy in the hohlraum could cause near 10 MJ output for a pellet with 0.2 mg DT fuel. We have compared results with and without α-particle transport, it shows that in the condition of ρR>0.5 g/cm 2 of DT fuel, both have the same results. For the system with ρR≅0.5 g/cm 2 we can use α-particle local deposition scheme. The non-uniformly doped tamper with density ρ≅1-5 g/cc can reduce mixing due to the small convergence ratio. The input energy is deposited in DT and tamper during the implosion, we try to reduce the tamper energy by changing the ratio of CH and doped Au and the thickness of the tamper

Ignition inhibitors for cellulosic materials

International Nuclear Information System (INIS)

Alvares, N.J.

1976-01-01

By exposing samples to various irradiance levels from a calibrated thermal radiation source, the ignition responses of blackened alpha-cellulose and cotton cloth with and without fire-retardant additives were compared. Samples treated with retardant compounds which showed the most promise were then isothermally pyrolyzed in air for comparisons between the pyrolysis rates. Alpha-cellulose samples containing a mixture of boric acid, borax, and ammonium di-hydrogen phosphate could not be ignited by irradiances up to 4.0 cal cm -2 s-1 (16.7 W/cm 2 ). At higher irradiances the specimens ignited, but flaming lasted only until the flammable gases were depleted. Cotton cloth containing a polymeric retardant with the designation THPC + MM was found to be ignition-resistant to all irradiances below 7.0 cal cm -2 s -1 (29.3 W/cm 2 ). Comparison of the pyrolysis rates of the retardant-treated alpha-cellulose and the retardant-treated cotton showed that the retardant mechanism is qualitatively the same. Similar ignition-response measurements were also made with specimens exposed to ionizing radiation. It was observed that gamma radiation results in ignition retardance of cellulose, while irradiation by neutrons does not

A polygon-based modeling approach to assess exposure of resources and assets to wildfire

Science.gov (United States)

Matthew P. Thompson; Joe Scott; Jeffrey D. Kaiden; Julie W. Gilbertson-Day

2013-01-01

Spatially explicit burn probability modeling is increasingly applied to assess wildfire risk and inform mitigation strategy development. Burn probabilities are typically expressed on a per-pixel basis, calculated as the number of times a pixel burns divided by the number of simulation iterations. Spatial intersection of highly valued resources and assets (HVRAs) with...

Exposure to electrocution by automotive ignition system in the work environment of car service employees

Directory of Open Access Journals (Sweden)

Bernard Fryśkowski

2014-06-01

Full Text Available Automotive ignition system diagnostic procedures involve a specific kind of action due to the presence of high voltage pulses rated of roughly several dozen kilovolts. Therefore, the repairers employed at car service coming into direct contact with electrical equipment of ignition systems are exposed to risk of electric shock. Typically, the electric discharge energy of automotive ignition systems is not high enough to cause fibrillation due to the electric effect on the heart. Nevertheless, there are drivers and car service employees who use electronic cardiac pacemakers susceptible to high voltage pulses. The influence of high-voltage ignition systems on the human body, especially in case of electric injury, has not been comprehensively elucidated. Therefore, relatively few scientific papers address this problem. The aim of this paper is to consider the electrical injury danger from automotive ignition systems, especially in people suffering from cardiac diseases. Some examples of the methods to reduce electric shock probability during diagnostic procedures of spark-ignition combustion engines are presented and discussed. Med Pr 2014;65(3:419–427

Numerical Analysis of the Interaction between Thermo-Fluid Dynamics and Auto-Ignition Reaction in Spark Ignition Engines

Science.gov (United States)

Saijyo, Katsuya; Nishiwaki, Kazuie; Yoshihara, Yoshinobu

The CFD simulations were performed integrating the low-temperature oxidation reaction. Analyses were made with respect to the first auto-ignition location in the case of a premixed-charge compression auto-ignition in a laminar flow field and in the case of the auto-ignition in an end gas during an S. I. Engine combustion process. In the latter simulation, the spatially-filtered transport equations were solved to express fluctuating temperatures in a turbulent flow in consideration of strong non-linearity to temperature in the reaction equations. It is suggested that the first auto-ignition location does not always occur at higher-temperature locations and that the difference in the locations of the first auto-ignition depends on the time period during which the local end gas temperature passes through the region of shorter ignition delay, including the NTC region.

Effects of wildfire on soil nutrients in Mediterranean ecosystem

NARCIS (Netherlands)

Caon, L.; Vallejo, V.R.; Ritsema, C.J.; Geissen, V.

2014-01-01

High-intensity and fast-spreading wildfires are natural in the Mediterranean basin. However, since 1960, wildfire occurrence has increased because of changes in land use, which resulted in extensive land abandonment, increases in the fuel load and continuity in the landscape. The level of soil

Heavy ion fusion targets; issues for fast ignition

International Nuclear Information System (INIS)

Bangerter, Roger O.

2014-01-01

During the last 36 years researchers have suggested and evaluated a large number of target designs for heavy ion inertial fusion. The different target designs can be classified according to their mode of ignition, their method of implosion, and their size. Ignition modes include hot-spot ignition and fast ignition. Methods of implosion include direct drive and indirect drive. Historically there has been significant work on indirectly driven targets with hot-spot ignition. Recently there has been increasing interest in directly driven targets with ion driven fast ignition. In principle, fast ignition might lead to improved target performance. On the other hand, fast ignition imposes stringent requirements on accelerators and beam physics. Furthermore, fast ignition magnifies the importance of a number of traditional target physics issues associated with ion beam energy deposition and fuel preheat. This paper will discuss the advantages and disadvantages of the various classes of targets. It will also discuss some issues that must be resolved to assess the feasibility of ion fast ignition

Post-wildfire soil erosion in the Mediterranean: Review and future research directions

Science.gov (United States)

Shakesby, R. A.

2011-04-01

Wildfires increased dramatically in frequency and extent in the European Mediterranean region from the 1960s, aided by a general warming and drying trend, but driven primarily by socio-economic changes, including rural depopulation, land abandonment and afforestation with flammable species. Published research into post-wildfire hydrology and soil erosion, beginning during the 1980s in Spain, has been followed by studies in other European Mediterranean countries together with Israel and has now attained a sufficiently large critical mass to warrant a major review. Although variations in climate, vegetation, soil, topography and fire severity cause differences in Mediterranean post-wildfire erosion, the long history of human landscape impact up to the present day is responsible for some its distinctive characteristics. This paper highlights these characteristics in reviewing wildfire impacts on hydrology, soil properties and soil erosion by water. The 'mosaic' nature of many Mediterranean landscapes (e.g. an intricate land-use pattern, abandoned terraces and tracks interrupting slopes) may explain sometimes conflicting post-fire hydrological and erosional responses at different sites and spatial scales. First-year post-wildfire soil losses at point- (average, 45-56 t ha - 1 ) and plot-scales (many Aspect is important, with more erosion reported for south- than north-facing slopes, which is attributed to greater fire frequency, slower vegetation recovery on the former and with soil characteristics more prone to erosion (e.g. lower aggregate stability). Post-fire wind erosion is a potentially important but largely neglected process. Gauging the degradational significance of wildfires has relied on comparison with unburnt land, but the focus for comparison should be switched to other agents of soil disturbance and/or currently poorly understood soil renewal rates. Human impact on land use and vegetation may alter expected effects (increased fire activity and post-wildfire

Fundamental Studies of Ignition Process in Large Natural Gas Engines Using Laser Spark Ignition

Energy Technology Data Exchange (ETDEWEB)

Azer Yalin; Bryan Willson

2008-06-30

Past research has shown that laser ignition provides a potential means to reduce emissions and improve engine efficiency of gas-fired engines to meet longer-term DOE ARES (Advanced Reciprocating Engine Systems) targets. Despite the potential advantages of laser ignition, the technology is not seeing practical or commercial use. A major impediment in this regard has been the 'open-path' beam delivery used in much of the past research. This mode of delivery is not considered industrially practical owing to safety factors, as well as susceptibility to vibrations, thermal effects etc. The overall goal of our project has been to develop technologies and approaches for practical laser ignition systems. To this end, we are pursuing fiber optically coupled laser ignition system and multiplexing methods for multiple cylinder engine operation. This report summarizes our progress in this regard. A partial summary of our progress includes: development of a figure of merit to guide fiber selection, identification of hollow-core fibers as a potential means of fiber delivery, demonstration of bench-top sparking through hollow-core fibers, single-cylinder engine operation with fiber delivered laser ignition, demonstration of bench-top multiplexing, dual-cylinder engine operation via multiplexed fiber delivered laser ignition, and sparking with fiber lasers. To the best of our knowledge, each of these accomplishments was a first.

Wildfires in Chile: A review

Science.gov (United States)

Úbeda, Xavier; Sarricolea, Pablo

2016-11-01

This paper reviews the literature examining the wildfire phenomenon in Chile. Since ancient times, Chile's wildfires have shaped the country's landscape, but today, as in many other parts of the world, the fire regime - pattern, frequency and intensity - has grown at an alarming rate. In 2014, > 8000 fires were responsible for burning c. 130,000 ha, making it the worst year in Chile's recent history. The reasons for this increase appear to be the increment in the area planted with flammable species; the rejection of these landscape modifications on the part of local communities that target these plantations in arson attacks; and, the adoption of intensive forest management practices resulting in the accumulation of a high fuel load. These trends have left many native species in a precarious situation and forest plantation companies under considerable financial pressure. An additional problem is posed by fires at the wildland urban interface (WUI), threatening those inhabitants that live in Chile's most heavily populated cities. The prevalence of natural fires in Chile; the relationship between certain plant species and fire in terms of seed germination strategies and plant adaptation; the relationship between fire and invasive species; and, the need for fire prevention systems and territorial plans that include fire risk assessments are some of the key aspects discussed in this article. Several of the questions raised will require further research, including just how fire-dependent the ecosystems in Chile are, how the forest at the WUI can be better managed to prevent human and material damage, and how best to address the social controversy that pits the Mapuche population against the timber companies.

Lubricant induced pre-ignition in an optical spark-ignition engine

OpenAIRE

Dingle, Simon Frederick

2014-01-01

This thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University London This work focuses on the introduction of lubricant into the combustion chamber and the effect that this has on pre-ignition. Apparently for the first time, the work presented provides detailed full-bore optical data for lubricant induced pre-ignition and improves understanding of the super-knock phenomena that affects modern downsized gasoline engines. A new single-cylinder optical r...

Predicting wildfires

Science.gov (United States)

Patricia Andrews; Mark Finney; Mark Fischetti

2007-01-01

The number of catastrophic wildfires in the U.S. has been steadily rising. The nation has spent more than $1 billion annually to suppress such fires in eight of the past 10 years. In 2005 a record 8.7 million acres burned, only to be succeeded by 9.9 million acres in 2006. And this year is off to a furious start. To a great extent, the increase in fires stems from a...

50 CFR 35.7 - Control of wildfires, insects, pest plants, and disease.

Science.gov (United States)

2010-10-01

... 50 Wildlife and Fisheries 6 2010-10-01 2010-10-01 false Control of wildfires, insects, pest plants... MANAGEMENT General Rules § 35.7 Control of wildfires, insects, pest plants, and disease. To the extent necessary, the Director shall prescribe measures to control wildfires, insects, pest plants, and disease to...

Studies into laser ignition of confined pyrotechnics

Energy Technology Data Exchange (ETDEWEB)

Ahmad, S.R.; Russell, D.A. [Centre for Applied Laser Spectroscopy, DASSR, Defence Academy, Cranfield University, Shrivenham, Swindon (United Kingdom)

2008-10-15

Ignition tests were carried out on three different pyrotechnics using laser energy from the multimode output from an Ar-Ion laser (av) at 500 nm and a near-IR diode laser pigtailed to a fibre optic cable and operating at 808 nm. The pyrotechnics investigated were: G20 black powder, SR44 and SR371C. The confined ignition tests were conducted in a specially designed ignition chamber. Pyrotechnics were ignited by a free space beam entering the chamber through an industrial sapphire window in the case of the Ar-ion laser. For the NIR diode laser, fibre was ducted through a block into direct contact with the pyrotechnic. The Ar-Ion laser was chosen as this was found to ignite all three pyrotechnics in the unconfined condition. It also allowed for a direct comparison of confined/unconfined results to be made. The threshold laser flux densities to initiate reproducible ignitions at this wavelength were found to be between {proportional_to}12.7 and {proportional_to}0.16 kW cm{sup -2}. Plotted on the ignition maps are the laser flux densities versus the start of ignition times for the three confined pyrotechnics. It was found from these maps that the times for confined ignition were substantially lower than those obtained for unconfined ignition under similar experimental conditions. For the NIR diode laser flux densities varied between {proportional_to}6.8 and {proportional_to}0.2 kW cm{sup -2}. The minimum ignition times for the NIR diode laser for SR371C ({proportional_to}11.2 ms) and G20 ({proportional_to}17.1 ms) were faster than those achieved by the use of the Ar-ion laser. However, the minimum ignition time was shorter ({proportional_to}11.7 ms) with the Ar-ion laser for SR44. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

Relating the octane numbers of fuels to ignition delay times measured in an ignition quality tester (IQT)

KAUST Repository

Naser, Nimal; Yang, Seung Yeon; Kalghatgi, Gautam; Chung, Suk-Ho

2016-01-01

an ignition quality tester. A baseline data of ignition delay times were determined using an ignition quality tester at a charge pressure of 21.3 bar between 770 and 850 K and an equivalence ratio of 0.7 for various primary reference fuels (PRFs, mixtures

Central ignition scenarios for TFTR

International Nuclear Information System (INIS)

Zweben, S.J.; Redi, M.H.; Bateman, G.

1986-03-01

The possibility of obtaining ignition in TFTR by means of very centrally peaked density profiles is examined. It is shown that local central alpha heating can be made to exceed local central energy losses (''central ignition'') under global conditions for which Q greater than or equal to 1. Time dependent 1-D transport simulations show that the normal global ignition requirements are substantially relaxed for plasmas with peaked density profiles. 18 refs., 18 figs

Modelling piloted ignition of wood and plastics

International Nuclear Information System (INIS)

Blijderveen, Maarten van; Bramer, Eddy A.; Brem, Gerrit

2012-01-01

Highlights: ► We model piloted ignition times of wood and plastics. ► The model is applied on a packed bed. ► When the air flow is above a critical level, no ignition can take place. - Abstract: To gain insight in the startup of an incinerator, this article deals with piloted ignition. A newly developed model is described to predict the piloted ignition times of wood, PMMA and PVC. The model is based on the lower flammability limit and the adiabatic flame temperature at this limit. The incoming radiative heat flux, sample thickness and moisture content are some of the used variables. Not only the ignition time can be calculated with the model, but also the mass flux and surface temperature at ignition. The ignition times for softwoods and PMMA are mainly under-predicted. For hardwoods and PVC the predicted ignition times agree well with experimental results. Due to a significant scatter in the experimental data the mass flux and surface temperature calculated with the model are hard to validate. The model is applied on the startup of a municipal waste incineration plant. For this process a maximum allowable primary air flow is derived. When the primary air flow is above this maximum air flow, no ignition can be obtained.

Assessing exposure of human and ecological values to wildfire in Sardinia, Italy

Science.gov (United States)

Michele Salis; Alan A. Ager; Bachisio Arca; Mark A. Finney; Valentina Bacciu; Pierpaolo Duce; Donatella. Spano

2012-01-01

We used simulation modelling to analyze spatial variation in wildfire exposure relative to key social and economic features on the island of Sardinia, Italy. Sardinia contains a high density of urban interfaces, recreational values and highly valued agricultural areas that are increasingly being threatened by severe wildfires. Historical fire data and wildfire...

Current research issues related to post-wildfire runoff and erosion processes

Science.gov (United States)

Moody, John A.; Shakesby, Richard A.; Robichaud, Peter R.; Cannon, Susan H.; Martin, Deborah A.

2013-01-01

Research into post-wildfire effects began in the United States more than 70 years ago and only later extended to other parts of the world. Post-wildfire responses are typically transient, episodic, variable in space and time, dependent on thresholds, and involve multiple processes measured by different methods. These characteristics tend to hinder research progress, but the large empirical knowledge base amassed in different regions of the world suggests that it should now be possible to synthesize the data and make a substantial improvement in the understanding of post-wildfire runoff and erosion response. Thus, it is important to identify and prioritize the research issues related to post-wildfire runoff and erosion. Priority research issues are the need to: (1) organize and synthesize similarities and differences in post-wildfire responses between different fire-prone regions of the world in order to determine common patterns and generalities that can explain cause and effect relations; (2) identify and quantify functional relations between metrics of fire effects and soil hydraulic properties that will better represent the dynamic and transient conditions after a wildfire; (3) determine the interaction between burned landscapes and temporally and spatially variable meso-scale precipitation, which is often the primary driver of post-wildfire runoff and erosion responses; (4) determine functional relations between precipitation, basin morphology, runoff connectivity, contributing area, surface roughness, depression storage, and soil characteristics required to predict the timing, magnitudes, and duration of floods and debris flows from ungaged burned basins; and (5) develop standard measurement methods that will ensure the collection of uniform and comparable runoff and erosion data. Resolution of these issues will help to improve conceptual and computer models of post-wildfire runoff and erosion processes.

Ignition of Cellulosic Paper at Low Radiant Fluxes

Science.gov (United States)

White, K. Alan

1996-01-01

The ignition of cellulosic paper by low level thermal radiation is investigated. Past work on radiative ignition of paper is briefly reviewed. No experimental study has been reported for radiative ignition of paper at irradiances below 10 Watts/sq.cm. An experimental study of radiative ignition of paper at these low irradiances is reported. Experimental parameters investigated and discussed include radiant power levels incident on the sample, the method of applying the radiation (focussed vs. diffuse Gaussian source), the presence and relative position of a separate pilot ignition source, and the effects of natural convection (buoyancy) on the ignition process in a normal gravity environment. It is observed that the incident radiative flux (in W/sq.cm) has the greatest influence on ignition time. For a given flux level, a focussed Gaussian source is found to be advantageous to a more diffuse, lower amplitude, thermal source. The precise positioning of a pilot igniter relative to gravity and to the fuel sample affects the ignition process, but the precise effects are not fully understood. Ignition was more readily achieved and sustained with a horizontal fuel sample, indicating the buoyancy plays a role in the ignition process of cellulosic paper. Smoldering combustion of doped paper samples was briefly investigated, and results are discussed.

Integrating wildfire plume rises within atmospheric transport models

Science.gov (United States)

Mallia, D. V.; Kochanski, A.; Wu, D.; Urbanski, S. P.; Krueger, S. K.; Lin, J. C.

2016-12-01

Wildfires can generate significant pyro-convection that is responsible for releasing pollutants, greenhouse gases, and trace species into the free troposphere, which are then transported a significant distance downwind from the fire. Oftentimes, atmospheric transport and chemistry models have a difficult time resolving the transport of smoke from these wildfires, primarily due to deficiencies in estimating the plume injection height, which has been highlighted in previous work as the most important aspect of simulating wildfire plume transport. As a result of the uncertainties associated with modeled wildfire plume rise, researchers face difficulties modeling the impacts of wildfire smoke on air quality and constraining fire emissions using inverse modeling techniques. Currently, several plume rise parameterizations exist that are able to determine the injection height of fire emissions; however, the success of these parameterizations has been mixed. With the advent of WRF-SFIRE, the wildfire plume rise and injection height can now be explicitly calculated using a fire spread model (SFIRE) that is dynamically linked with the atmosphere simulated by WRF. However, this model has only been tested on a limited basis due to computational costs. Here, we will test the performance of WRF-SFIRE in addition to several commonly adopted plume parameterizations (Freitas, Sofiev, and Briggs) for the 2013 Patch Springs (Utah) and 2012 Baker Canyon (Washington) fires, for both of which observations of plume rise heights are available. These plume rise techniques will then be incorporated within a Lagrangian atmospheric transport model (STILT) in order to simulate CO and CO2 concentrations during NASA's CARVE Earth Science Airborne Program over Alaska during the summer of 2012. Initial model results showed that STILT model simulations were unable to reproduce enhanced CO concentrations produced by Alaskan fires observed during 2012. Near-surface concentrations were drastically

The Effect of Prescribed Burns and Wildfire on Vegetation in Bastrop State Park, TX

Science.gov (United States)

Justice, C. J.

2014-12-01

In 2011, central Texas had its worst drought since the 1950's. This, in conjunction with the strong winds produced by Tropical Storm Lee created conditions that made possible the Bastrop County Complex Fire in September 2011. These record-breaking wildfires burned over 95% of the 6,565-acre Bastrop State Park (BSP). Since 2003, BSP had been using prescribed burns as a management practice to reduce fuel load and prevent high severity wildfires. Although these prescribed fires did not prevent the 2011 wildfires they may have mitigated their effects. This study considered the effect of prescribed burn history and wildfire burn severity on vegetation recovery in BSP since the 2011 wildfire. The hypotheses of this study are that prescribed burn history and wildfire burn severity separately and jointly have affected post wildfire vegetation. To test these hypotheses, data were collected in 2013 from 46 plots across BSP using the Fire Effects Monitoring and Inventory (FIREMON) protocol to determine herbaceous plant density, shrub density, overstory density, and midstory tree density. Data were analyzed using analyses of variance (ANOVA) to determine the effects of prescribed fire and wildfire severity on these vegetation measurements. It was found that more severely burned plots had more herbaceous plants, fewer midstory trees, and lower shrub densities than less severely burned plots. Contrary to an initial hypotheses, there were few relationships between prescribed burn history and wildfire effects. The only significant effect detected for prescribed burning was the positive effect of prescribed fire on midstory tree density, but only for plots that were not severely burned in the wildfire. In this system, burn severity had a greater effect on post-wildfire vegetation than prescribed burns.

Shock ignition targets: gain and robustness vs ignition threshold factor

Science.gov (United States)

Atzeni, Stefano; Antonelli, Luca; Schiavi, Angelo; Picone, Silvia; Volponi, Gian Marco; Marocchino, Alberto

2017-10-01

Shock ignition is a laser direct-drive inertial confinement fusion scheme, in which the stages of compression and hot spot formation are partly separated. The hot spot is created at the end of the implosion by a converging shock driven by a final ``spike'' of the laser pulse. Several shock-ignition target concepts have been proposed and relevant gain curves computed (see, e.g.). Here, we consider both pure-DT targets and more facility-relevant targets with plastic ablator. The investigation is conducted with 1D and 2D hydrodynamic simulations. We determine ignition threshold factors ITF's (and their dependence on laser pulse parameters) by means of 1D simulations. 2D simulations indicate that robustness to long-scale perturbations increases with ITF. Gain curves (gain vs laser energy), for different ITF's, are generated using 1D simulations. Work partially supported by Sapienza Project C26A15YTMA, Sapienza 2016 (n. 257584), Eurofusion Project AWP17-ENR-IFE-CEA-01.

Qualification of Magnesium/Teflon/Viton Pyrotechnic Composition Used in Rocket Motors Ignition System

Directory of Open Access Journals (Sweden)

Luciana de Barros

2016-04-01

Full Text Available The application of fluoropolymers in high-energy-release pyrotechnic compositions is common in the space and defense areas. Pyrotechnic compositions of magnesium/Teflon/Viton are widely used in military flares and pyrogen igniters for igniting the solid propellant of a rocket motor. Pyrotechnic components are considered high-risk products as they may cause catastrophic accidents if initiated or ignited inadvertently. To reduce the hazards involved in the handling, storage and transportation of these devices, the magnesium/Teflon/Viton composition was subjected to various sensitivity tests, DSC and had its stability and compatibility tested with other materials. This composition obtained satisfactory results in all the tests, which qualifies it as safe for production, handling, use, storage and transportation.

14 CFR 33.69 - Ignitions system.

Science.gov (United States)

2010-01-01

... STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.69 Ignitions system. Each..., except that only one igniter is required for fuel burning augmentation systems. [Amdt. 33-6, 39 FR 35466... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Ignitions system. 33.69 Section 33.69...

Assessing fire risk in the wildland-urban interface.

Science.gov (United States)

Robert G. Haight; David T. Cleland; Roger B. Hammer; Volker B. Radeloff; T. Scott Rupp

2004-01-01

Identifying areas of the wildland-urban interface (WUI) that are prone to severe wildfire is an important step in prioritizing fire prevention and preparedness projects. Our objective is to determine at a regional scale the relative risk of severe wildfire in WUI areas and the numbers of people and houses in high-risk areas. For a study area in northern lower Michigan...

Physical studies of fast ignition in China

International Nuclear Information System (INIS)

He, X T; Cai, Hong-bo; Wu, Si-zhong; Cao, Li-hua; Zhang, Hua; He, Ming-qing; Chen, Mo; Wu, Jun-feng; Zhou, Cang-tao; Zhou, Wei-Min; Shan, Lian-qiang; Wang, Wei-wu; Zhang, Feng; Bi, Bi; Zhao, Zong-qing; Gu, Yu-qiu; Zhang, Bao-han; Wang, Wei; Fang, Zhi-heng; Lei, An-le

2015-01-01

Fast ignition approach to inertial confinement fusion is one of the important goals today, in addition to central hot spot ignition in China. The SG-IIU and PW laser facilities are coupled to investigate the hot spot formation for fast ignition. The SG-III laser facility is almost completed and will be coupled with tens kJ PW lasers for the demonstration of fast ignition. In recent years, for physical studies of fast ignition, we have been focusing on the experimental study of implosion symmetry, M-band radiation preheating and mixing, advanced fast ignition target design, and so on. In addition, the modeling capabilities and code developments enhanced our ability to perform the hydro-simulation of the compression implosion, and the particle-in-cell (PIC) and hybrid-PIC simulation of the generation, transport and deposition of relativistic electron beams. Considerable progress has been achieved in understanding the critical issues of fast ignition. (paper)

Incorporating fine-scale drought information into an eastern US wildfire hazard model

Science.gov (United States)

Matthew P. Peters; Louis R. Iverson

2017-01-01

Wildfires in the eastern United States are generally caused by humans in locations where human development and natural vegetation intermingle, e.g. the wildland–urban interface (WUI). Knowing where wildfire hazards are elevated across the forested landscape may help land managers and property owners plan or allocate resources for potential wildfire threats. In an...

The Application for a Prediction of the Coal Spontaneous Ignition - Predisam

Science.gov (United States)

Moni, Vlastimil; Klouda, Petr; Blata, Jan; Helebrant, František

2017-06-01

The article follows the research of the project number TA01020351 called "The research of possibilities when predicting steam origin and consequent spontaneous ignition of brown coal fuels" which was researched with the support of the Technological Agency in the Czech Republic in 2011-2014 in the connection with a realized technical research. Therefore, it gives a summary information about the evaluation of the risk degree for the origin of spontaneous ignitions of the brown coal. The presented way of evaluation is based on a numeric expression of a value for MHU criteria - the point load of particular indicators is added together with other results gained from this research project. Then, more information is taken from companies running the dumps of brown coal products - both for suppliers (mining companies) and big consumers (power engineering). The complex knowledge about prediction of the origin of the spontaneous ignition enables to make an early response to eliminate a threat of mining fire in open pit mines or on the dumps of coal products. Consequently, it reduces the risk of fire and breakdowns of transportation means DPD, heavy machines and preparation plants. The working injuries are reduced as well - burns by coal in fire or inhalation of gas products from imperfect combustion.

Hot-wire ignition of AN-based emulsions

Energy Technology Data Exchange (ETDEWEB)

Turcotte, Richard; Goldthorp, Sandra; Badeen, Christopher M. [Canadian Explosives Research Laboratory, Natural Resources Canada, Ottawa, Ontario, K1A 0G1 (Canada); Chan, Sek Kwan [Orica Canada Inc., Brownsburg-Chatham, Quebec (Canada)

2008-12-15

Emulsions based on ammonium nitrate (AN) and water locally ignited by a heat source do not undergo sustained combustion when the pressure is lower than some threshold value usually called the Minimum Burning Pressure (MBP). This concept is now being used by some manufacturers as a basis of safety. However, before a technique to reliably measure MBP values can be designed, one must have a better understanding of the ignition mechanism. Clearly, this is required to avoid under ignitions which could lead to the erroneous interpretation of failures to ignite as failures to propagate. In the present work, facilities to prepare and characterize emulsions were implemented at the Canadian Explosives Research Laboratory. A calibrated hot-wire ignition system operated in a high-pressure vessel was also built. The system was used to study the ignition characteristics of five emulsion formulations as a function of pressure and ignition source current. It was found that these mixtures exhibit complicated pre-ignition stages and that the appearance of endotherms when the pressure is lowered below some threshold value correlates with the MBP. Thermal conductivity measurements using this hot-wire system are also reported. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

Overlapping Bark Beetle Outbreaks, Salvage Logging and Wildfire Restructure a Lodgepole Pine Ecosystem

Directory of Open Access Journals (Sweden)

Charles C. Rhoades

2018-02-01

Full Text Available The 2010 Church’s Park Fire burned beetle-killed lodgepole pine stands in Colorado, including recently salvage-logged areas, creating a fortuitous opportunity to compare the effects of salvage logging, wildfire and the combination of logging followed by wildfire. Here, we examine tree regeneration, surface fuels, understory plants, inorganic soil nitrogen and water infiltration in uncut and logged stands, outside and inside the fire perimeter. Subalpine fir recruitment was abundant in uncut, unburned, beetle-killed stands, whereas lodgepole pine recruitment was abundant in cut stands. Logging roughly doubled woody fuel cover and halved forb and shrub cover. Wildfire consumed all conifer seedlings in uncut and cut stands and did not stimulate new conifer regeneration within four years of the fire. Aspen regeneration, in contrast, was relatively unaffected by logging or burning, alone or combined. Wildfire also drastically reduced cover of soil organic horizons, fine woody fuels, graminoids and shrubs relative to unburned, uncut areas; moreover, the compound effect of logging and wildfire was generally similar to wildfire alone. This case study documents scarce conifer regeneration but ample aspen regeneration after a wildfire that occurred in the later stage of a severe beetle outbreak. Salvage logging had mixed effects on tree regeneration, understory plant and surface cover and soil nitrogen, but neither exacerbated nor ameliorated wildfire effects on those resources.

Relating the octane numbers of fuels to ignition delay times measured in an ignition quality tester (IQT)

KAUST Repository

Naser, Nimal

2016-09-21

A methodology for estimating the octane index (OI), the research octane number (RON) and the motor octane number (MON) using ignition delay times from a constant volume combustion chamber with liquid fuel injection is proposed by adopting an ignition quality tester. A baseline data of ignition delay times were determined using an ignition quality tester at a charge pressure of 21.3 bar between 770 and 850 K and an equivalence ratio of 0.7 for various primary reference fuels (PRFs, mixtures of isooctane and n-heptane). Our methodology was developed using ignition delay times for toluene reference fuels (mixtures of toluene and n-heptane). A correlation between the OI and the ignition delay time at the initial charge temperature enabled the OI of non-PRFs to be predicted at specified temperatures. The methodology was validated using ignition delay times for toluene primary reference fuels (ternary mixtures of toluene, iso-octane, and n-heptane), fuels for advanced combustion engines (FACE) gasolines, and certification gasolines. Using this methodology, the RON, the MON, and the octane sensitivity were estimated in agreement with values obtained from standard test methods. A correlation between derived cetane number and RON is also provided. (C) 2016 Elsevier Ltd. All rights reserved.

Wildfire Dynamics and Occasional Precipitation during Active Fire Season in Tropical Lowland of Nepal

Directory of Open Access Journals (Sweden)

Krishna Bahadur Bhujel

2017-10-01

Full Text Available Occasional precipitation plays a vital role in reducing the effect of wildfire. This precipitation is especially important for countries like Nepal, where wildfires are a common seasonal event. Approximately 0.1 million hectare of forest area is affected annually due to wildfires in active fire season. The study on the relation of these forms of occasional precipitation with wildfire incidence is still lacking. This research was objectively carried out to examine the correlation of occasional precipitation with wildfire incidence and burnt area. The Moderate Resolution Imaging Spector-Radiometer (MODIS satellite images and precipitation records for 15 years gathered from Department of Hydrology and Metrology were used as input data for this study. The images were analyzed by using ArcGIS function while the precipitation records were analyzed by using Statistical Package for the Social Science (SPSS program. The linear regression model was applied to find correlation of occasional precipitation with wildfire incidence and burnt area. Analysis revealed decreasing trend of precipitation in study area. We found significant correlation (p<0.05 of precipitation with wildfire incidence and burnt area. Findings will be useful for policy makers, implementers and researchers to manage wildfire in sustainable basis.

Desensitizing nano powders to electrostatic discharge ignition

International Nuclear Information System (INIS)

Steelman, Ryan; Daniels, Michael A.

2015-01-01

Electrostatic discharge (ESD) is a main cause for ignition in powder media ranging from grain silos to fireworks. Nanoscale particles are orders of magnitude more ESD ignition sensitive than their micron scale counterparts. This study shows that at least 13 vol. % carbon nanotubes (CNT) added to nano-aluminum and nano-copper oxide particles (nAl + CuO) eliminates ESD ignition sensitivity. The CNT act as a conduit for electric energy and directs electric charge through the powder to desensitize the reactive mixture to ignition. For nanoparticles, the required CNT concentration for desensitizing ESD ignition acts as a diluent to quench energy propagation.

Public Response to Wildfire: Is the Australian "Stay and Defend or Leave Early" Approach an Option for Wildfire Management in the United States?

Science.gov (United States)

Sarah M. McCaffrey; Alan Rhodes

2009-01-01

In the United States, the increasing costs and negative impacts of wildfires are causing fire managers and policymakers to reexamine traditional approaches to fire management including whether mass evacuation of populations threatened by wildfire is always the most appropriate option. This article examines the Australian "stay and defend or leave early" (SDLE...

Ignition circuit for combustion engines

Energy Technology Data Exchange (ETDEWEB)

Becker, H W

1977-05-26

The invention refers to the ignition circuit for combustion engines, which are battery fed. The circuit contains a transistor and an oscillator to produce an output voltage on the secondary winding of an output transformer to supply an ignition current. The plant is controlled by an interrupter. The purpose of the invention is to form such a circuit that improved sparks for ignition are produced, on the one hand, and that on the other hand, the plant can continue to function after loss of the oscillator. The problem is solved by the battery and the secondary winding of the output transformers of the oscillator are connected via a rectifier circuit to produce a resultant total voltage with the ignition coil from the battery voltage and the rectified pulsating oscillator output.

The national ignition facility: path to ignition in the laboratory

International Nuclear Information System (INIS)

Moses, E.I.; Bonanno, R.E.; Haynam, C.A.; Kauffman, R.L.; MacGowan, B.J.; Patterson Jr, R.W.; Sawicki, R.H.; Van Wonterghem, B.M.

2007-01-01

The National Ignition Facility (NIF) is a 192-beam laser facility presently under construction at Lawrence Livermore National Laboratory. When completed, NIF will be a 1.8-MJ, 500-TW ultraviolet laser system. Its missions are to obtain fusion ignition of deuterium-tritium plasmas in ICF (Inertial Confinement Fusion) targets and to perform high energy density experiments in support of the U.S. nuclear weapons stockpile. The NIF facility will consist of 2 laser bays, 4 capacitor areas, 2 laser switchyards, the target area and the building core. The laser is configured in 4 clusters of 48 beams, 2 in each laser bay. Four of the NIF beams have been already commissioned to demonstrate laser performance and to commission the target area including target and beam alignment and laser timing. During this time, NIF has demonstrated on a single-beam basis that it will meet its performance goals and has demonstrated its precision and flexibility for pulse shaping, pointing, timing and beam conditioning. It also performed 4 important experiments for ICF and High Energy Density Science. Presently, the project is installing production hardware to complete the project in 2009 with the goal to begin ignition experiments in 2010. An integrated plan has been developed including the NIF operations, user equipment such as diagnostics and cryogenic target capability, and experiments and calculations to meet this goal. This talk will provide NIF status, the plan to complete NIF, and the path to ignition. (authors)

Policy change and governance at the wildland-urban interface: the case of post-wildfire impacts in Boise, Idaho

Science.gov (United States)

Lindquist, Eric

2013-04-01

In the summer of 2012 over 1.7 million acres (approximately 6900 sq kilometers) were burned from wildfires in the state of Idaho in the Western United States. While most of the these fires were in rural and wilderness areas, several significant fires occurred at the wildland-urban interface (WUI), threatening houses, communities and the built environment as never before. As the population of the Mountain West in the United States grows, the WUI (the area where homes are being built adjacent to traditionally wild or rural areas and the built environment encroaches on wildlands) is rapidly becoming an at risk area for human habitation. Efforts to make these areas more resilient and sustainable in the face of increasing fire risk, due to increasing drought and climate change, are resulting in efforts to change or adapt disaster response and planning policy. An increase in stakeholders, however, with diverse objectives and resources presents an opportunity to assess the current governance situation for policy change in response to wildland fires in the dynamic and complex context of the WUI. The research presented here will focus on the case of Treasure Valley region of southwest Idaho and Boise, the capitol city of Idaho. This region is illustrative of the growing urban western United States and the pressures from a growing population pushing into the WUI. This research frames fire policy and decision making at the wildland-urban interface within public policy process theory using the example of the summer of 2012 forest fires in Idaho (USA) and focuses on subsequents impact these fires are having on fire planning and policy in the Boise metropolitan region. The focus is on the diverse stakeholders (federal, state and regional agencies, tourism, agriculture and private sector interests, homeowner organizations, and fire response and recovery agencies) and their roles and responsibilities, their interactions, decision and policy processes, the use of science in

Surface breakdown igniter for mercury arc devices

Science.gov (United States)

Bayless, John R.

1977-01-01

Surface breakdown igniter comprises a semiconductor of medium resistivity which has the arc device cathode as one electrode and has an igniter anode electrode so that when voltage is applied between the electrodes a spark is generated when electrical breakdown occurs over the surface of the semiconductor. The geometry of the igniter anode and cathode electrodes causes the igniter discharge to be forced away from the semiconductor surface.

Wildfire Detection and Tracking over Greece Using MSG‑SEVIRI Satellite Data

Directory of Open Access Journals (Sweden)

Nicolaos I. Sifakis

2011-03-01

Full Text Available Greece is a high risk Mediterranean country with respect to wildfires. This risk has been increasing under the impact of climate change, and in summer 2007 approximately 200,000 ha of vegetated land were burnt. The SEVIRI sensor, on board the Meteosat Second Generation (MSG geostationary satellite, is the only spaceborne sensor providing five and 15-minute observations of Europe in 12 spectral channels, including a short-wave infrared band sensitive to fire radiative temperature. In August 2007, when the bulk of the destructive wildfires started in Greece, the receiving station, operated by the Institute for Space Applications and Remote Sensing, provided us with a time series of MSG-SEVIRI images. These images were processed in order to test the reliability of a real‑time detection and tracking system and its complementarity to conventional means provided by the Fire Brigade. EUMETSAT’s Active Fire Monitoring (FIR image processing algorithm for fire detection and monitoring was applied to SEVIRI data, then fine-tuned according to Greek conditions, and evaluated. Alarm announcements from the Fire Brigade’s archives were used as ground truthing data in order to assess detection reliability and system performance. During the examined period, MSG-SEVIRI data successfully detected 82% of the fire events in Greek territory with less than 1% false alarms.

Evaluation of the Revolver Ignition Design at the National Ignition Facility Using Polar-Direct-Drive Illumination

Science.gov (United States)

McKenty, P. W.; Collins, T. J. B.; Marozas, J. A.; Campbell, E. M.; Molvig, K.; Schmitt, M.

2017-10-01

The direct-drive ignition design Revolver employs a triple-shell target using a beryllium ablator, a copper driver, and an eventual gold pusher. Symmetric numerical calculations indicate that each of the three shells exhibit low convergence ( 3to 5) resulting in a modest gain (G 4) for 1.7 MJ of incident laser energy. Studies are now underway to evaluate the robustness of this design employing polar direct drive (PDD) at the National Ignition Facility. Integral to these calculations is the leveraging of illumination conditioning afforded by research done to demonstrate ignition for a traditional PDD hot-spot target design. Two-dimensional simulation results, employing nonlocal electron-thermal transport and cross-beam energy transport, will be presented that indicate ignition using PDD. A study of the allowed levels of long-wavelength perturbations (target offset and power imbalance) not precluding ignition will also be examined. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

Wildfires Tracked by Minnesota DNR

Data.gov (United States)

Minnesota Department of Natural Resources — This theme shows the locations of wildfires for which the DNR was the primary responding agency. These include fires not only on state lands, but also rural private...

Design of a deuterium and tritium-ablator shock ignition target for the National Ignition Facility

International Nuclear Information System (INIS)

Terry, Matthew R.; Perkins, L. John; Sepke, Scott M.

2012-01-01

Shock ignition presents a viable path to ignition and high gain on the National Ignition Facility (NIF). In this paper, we describe the development of the 1D design of 0.5 MJ class, all-deuterium and tritium (fuel and ablator) shock ignition target that should be reasonably robust to Rayleigh-Taylor fluid instabilities, mistiming, and hot electron preheat. The target assumes “day one” NIF hardware and produces a yield of 31 MJ with reasonable allowances for laser backscatter, absorption efficiency, and polar drive power variation. The energetics of polar drive laser absorption require a beam configuration with half of the NIF quads dedicated to launching the ignitor shock, while the remaining quads drive the target compression. Hydrodynamic scaling of the target suggests that gains of 75 and yields 70 MJ may be possible.

Wildfire Mitigation and Private Lands: Managing Long-Term Vulnerabilities

Science.gov (United States)

Brian Muller; Stacey Schulte

2006-01-01

Long-term management of wildfire vulnerability requires strategies that address complex interactions between fire ecology and human settlement. In this paper, we examine the integration of wildfire mitigation and land use planning in county governments in the western U.S. This research relies on data from two sources. First, we conducted a survey of land use...

Physical characteristics of welding arc ignition process

Science.gov (United States)

Shi, Linan; Song, Yonglun; Xiao, Tianjiao; Ran, Guowei

2012-07-01

The existing research of welding arc mainly focuses on the stable combustion state and the research on the mechanism of welding arc ignition process is quite lack. The tungsten inert gas(TIG) touch arc ignition process is observed via a high speed camera and the high time resolution spectral diagnosis system. The changing phenomenon of main ionized element provided the electrons in the arc ignition is found. The metallic element is the main contributor to provide the electrons at the beginning of the discharging, and then the excitated shielding gas element replaces the function of the metallic element. The electron density during the period of the arc ignition is calculated by the Stark-broadened lines of Hα. Through the discussion with the repeatability in relaxation phenomenon, the statistical regularity in the arc ignition process is analyzed. The similar rules as above are observed through the comparison with the laser-assisted arc ignition experiments and the metal inert gas(MIG) arc ignition experiments. This research is helpful to further understanding on the generation mechanism of welding arc ignition and also has a certain academic and practical significance on enriching the welding physical theoretical foundation and improving the precise monitoring on automatic arc welding process.

Understanding Biomass Ignition in Power Plant Mills

DEFF Research Database (Denmark)

Schwarzer, Lars; Jensen, Peter Arendt; Glarborg, Peter

2017-01-01

. This is not very well explained by apply-ing conventional thermal ignition theory. An experimental study at lab scale, using pinewood as an example fuel, was conducted to examine self-heating and self-ignition. Supplemental experiments were performed with bituminous coal. Instead of characterizing ignition......Converting existing coal fired power plants to biomass is a readily implemented strategy to increase the share of renewable energy. However, changing from one fuel to another is not straightforward: Experience shows that wood pellets ignite more readily than coal in power plant mills or storages...... temperature in terms of sample volume, mass-scaling seems more physically correct for the self-ignition of solids. Findings also suggest that the transition between self-heating and self-ignition is controlled both by the availability of reactive material and temperature. Comparison of experiments at 20...

Laser Ignition Microthruster Experiments on KKS-1

Science.gov (United States)

Nakano, Masakatsu; Koizumi, Hiroyuki; Watanabe, Masashi; Arakawa, Yoshihiro

A laser ignition microthruster has been developed for microsatellites. Thruster performances such as impulse and ignition probability were measured, using boron potassium nitrate (B/KNO3) solid propellant ignited by a 1 W CW laser diode. The measured impulses were 60 mNs ± 15 mNs with almost 100 % ignition probability. The effect of the mixture ratios of B/KNO3 on thruster performance was also investigated, and it was shown that mixture ratios between B/KNO3/binder = 28/70/2 and 38/60/2 exhibited both high ignition probability and high impulse. Laser ignition thrusters designed and fabricated based on these data became the first non-conventional microthrusters on the Kouku Kousen Satellite No. 1 (KKS-1) microsatellite that was launched by a H2A rocket as one of six piggyback satellites in January 2009.

Development status of the ignition system for Vinci

NARCIS (Netherlands)

Frenken, G.; Vermeulen, E.; Bouquet, F.; Sanders, H.M.

2002-01-01

The development status of ignition system for the new cryogenic upper stage engine Vinci is presented. The concept differs from existing upper stage ignition systems as its functioning is engine independent. The system consists of a spark torch igniter, a highpressure igniter feed system and an

Development of fast ignition integrated interconnecting code (FI3) for fast ignition scheme

International Nuclear Information System (INIS)

Nagatomo, H.; Johzaki, T.; Mima, K.; Sunahara, A.; Nishihara, K.; Izawa, Y.; Sakagami, H.; Nakao, Y.; Yokota, T.; Taguchi, T.

2005-01-01

The numerical simulation plays an important role in estimating the feasibility and performance of the fast ignition. There are two key issues in numerical analysis for the fast ignition. One is the controlling the implosion dynamics to form a high density core plasma in non-spherical implosion, and the other is heating core plasma efficiency by the short pulse high intense laser. From initial laser irradiation to final fusion burning, all the physics are coupling strongly in any phase, and they must be solved consistently in computational simulation. However, in general, it is impossible to simulate laser plasma interaction and radiation hydrodynamics in a single computational code, without any numerical dissipation, special assumption or conditional treatment. Recently, we have developed 'Fast Ignition Integrated Interconnecting code' (FI 3 ) which consists of collective Particle-in-Cell code, Relativistic Fokker-Planck hydro code, and 2-dimensional radiation hydrodynamics code. And those codes are connecting with each other in data-flow bases. In this paper, we will present detail feature of the FI 3 code, and numerical results of whole process of fast ignition. (author)

The physics basis for ignition using indirect-drive targets on the National Ignition Facility

International Nuclear Information System (INIS)

Lindl, John D.; Amendt, Peter; Berger, Richard L.; Glendinning, S. Gail; Glenzer, Siegfried H.; Haan, Steven W.; Kauffman, Robert L.; Landen, Otto L.; Suter, Laurence J.

2004-01-01

The 1990 National Academy of Science final report of its review of the Inertial Confinement Fusion Program recommended completion of a series of target physics objectives on the 10-beam Nova laser at the Lawrence Livermore National Laboratory as the highest-priority prerequisite for proceeding with construction of an ignition-scale laser facility, now called the National Ignition Facility (NIF). These objectives were chosen to demonstrate that there was sufficient understanding of the physics of ignition targets that the laser requirements for laboratory ignition could be accurately specified. This research on Nova, as well as additional research on the Omega laser at the University of Rochester, is the subject of this review. The objectives of the U.S. indirect-drive target physics program have been to experimentally demonstrate and predictively model hohlraum characteristics, as well as capsule performance in targets that have been scaled in key physics variables from NIF targets. To address the hohlraum and hydrodynamic constraints on indirect-drive ignition, the target physics program was divided into the Hohlraum and Laser-Plasma Physics (HLP) program and the Hydrodynamically Equivalent Physics (HEP) program. The HLP program addresses laser-plasma coupling, x-ray generation and transport, and the development of energy-efficient hohlraums that provide the appropriate spectral, temporal, and spatial x-ray drive. The HEP experiments address the issues of hydrodynamic instability and mix, as well as the effects of flux asymmetry on capsules that are scaled as closely as possible to ignition capsules (hydrodynamic equivalence). The HEP program also addresses other capsule physics issues associated with ignition, such as energy gain and energy loss to the fuel during implosion in the absence of alpha-particle deposition. The results from the Nova and Omega experiments approach the NIF requirements for most of the important ignition capsule parameters, including

Impact of wildfires on ozone exceptional events in the Western u.s.

Science.gov (United States)

Jaffe, Daniel A; Wigder, Nicole; Downey, Nicole; Pfister, Gabriele; Boynard, Anne; Reid, Stephen B

2013-10-01

Wildfires generate substantial emissions of nitrogen oxides (NOx) and volatile organic compounds (VOCs). As such, wildfires contribute to elevated ozone (O3) in the atmosphere. However, there is a large amount of variability in the emissions of O3 precursors and the amount of O3 produced between fires. There is also significant interannual variability as seen in median O3, organic carbon and satellite derived carbon monoxide mixing ratios in the western U.S. To better understand O3 produced from wildfires, we developed a statistical model that estimates the maximum daily 8 h average (MDA8) O3 as a function of several meteorological and temporal variables for three urban areas in the western U.S.: Salt Lake City, UT; Boise, ID; and Reno, NV. The model is developed using data from June-September 2000-2012. For these three locations, the statistical model can explain 60, 52, and 27% of the variability in daily MDA8. The Statistical Model Residual (SMR) can give information on additional sources of O3 that are not explained by the usual meteorological pattern. Several possible O3 sources can explain high SMR values on any given day. We examine several cases with high SMR that are due to wildfire influence. The first case considered is for Reno in June 2008 when the MDA8 reached 82 ppbv. The wildfire influence for this episode is supported by PM concentrations, the known location of wildfires at the time and simulations with the Weather and Research Forecasting Model with Chemistry (WRF-Chem) which indicates transport to Reno from large fires burning in California. The contribution to the MDA8 in Reno from the California wildfires is estimated to be 26 ppbv, based on the SMR, and 60 ppbv, based on WRF-Chem. The WRF-Chem model also indicates an important role for peroxyacetyl nitrate (PAN) in producing O3 during transport from the California wildfires. We hypothesize that enhancements in PAN due to wildfire emissions may lead to regional enhancements in O3 during high

Places where wildfire potential and social vulnerability coincide in the coterminous United States

Science.gov (United States)

Gabriel Wigtil; Roger B. Hammer; Jeffrey D. Kline; Miranda H. Mockrin; Susan I. Stewart; Daniel Roper; Volker C. Radeloff

2016-01-01

The hazards-of-place model posits that vulnerability to environmental hazards depends on both biophysical and social factors. Biophysical factors determine where wildfire potential is elevated, whereas social factors determine where and how people are affected by wildfire. We evaluated place vulnerability to wildfire hazards in the coterminous US. We developed...

Understanding the Factors that Influence Perceptions of Post-Wildfire Landscape Recovery Across 25 Wildfires in the Northwestern United States

Science.gov (United States)

Kooistra, C.; Hall, T. E.; Paveglio, T.; Pickering, M.

2018-01-01

Disturbances such as wildfire are important features of forested landscapes. The trajectory of changes following wildfires (often referred to as landscape recovery) continues to be an important research topic among ecologists and wildfire scientists. However, the landscape recovery process also has important social dimensions that may or may not correspond to ecological or biophysical perspectives. Perceptions of landscape recovery may affect people's attitudes and behaviors related to forest and wildfire management. We explored the variables that influence people's perceptions of landscape recovery across 25 fires that occurred in 2011 or 2012 in the United States of Washington, Oregon, Idaho, and Montana and that represented a range of fire behavior characteristics and landscape impacts. Residents near each of the 25 fires were randomly selected to receive questionnaires about their experiences with the nearby fire, including perceived impacts and how the landscape had recovered since the fire. People generally perceived landscapes as recovering, even though only one to two years had passed. Regression analysis suggested that perceptions of landscape recovery were positively related to stronger beliefs about the ecological role of fire and negatively related to loss of landscape attachment, concern about erosion, increasing distance from the fire perimeter, and longer lasting fires. Hierarchical linear modeling (HLM) analysis indicated that the above relationships were largely consistent across fires. These findings highlight that perceptions of post-fire landscape recovery are influenced by more than vegetation changes and include emotional and cognitive factors. We discuss the management implications of these findings.

Smoke Ready Toolbox for Wildfires

Science.gov (United States)

This site provides an online Smoke Ready Toolbox for Wildfires, which lists resources and tools that provide information on health impacts from smoke exposure, current fire conditions and forecasts and strategies to reduce exposure to smoke.

Ion beam heating for fast ignition

International Nuclear Information System (INIS)

Gus'kov, S.Yu.; Limpouch, J.; Klimo, O.

2010-01-01

Complete text of publication follows. The characteristics features of the formation of the spatial distribution of the energy transferred to the plasma from a beam of ions with different initial energies, masses and charges under fast ignition conditions are determined. The motion of the Bragg peak is extended with respect to the spatial distribution of the temperature of the ion-beam-heated medium. The parameters of the ion beams are determined to initiate different regimes of fast ignition of thermonuclear fuel precompressed to a density of 300-500 g/cm 3 - the edge regime, in which the ignition region is formed at the outer boundary of the fuel, and the internal regime, in which the ignition region is formed in central parts of the fuel. The conclusion on the requirements for fast ignition by light and heavy ion beams is presented. It is shown that the edge heating with negative temperature gradient is described by a self-similar solution. Such a temperature distribution is the reason of the fact that the ignited beam energy at the edge heating is larger than the minimal ignition energy by factor 1.65. The temperature Bragg peak may be produced by ion beam heating in the reactor scale targets with pR-parameter larger than 3-4 g/cm 2 . In particular, for central ignition of the targets with pR-parameters in the range of 4-8 g/cm 2 the ion beam energy should be, respectively, from 5 to 7 times larger than the minimal ignition energy. The work by S.Ye. Gus'kov, D.V. Il'in, and V.E. Sherman was supported by the Ministry of Education and Science of the Russian Federation under the program 'Development of the Scientific Potential of High Education for 2009-2010' (project no. 2.1.1/1505) and the Russian Foundation for Basic Research (project no. 08-02-01394 a ). The work by J. Limpouch and O. Klimo was supported by the Czech Ministry of Education (project no. LC528, MSM6840770022).

Multitemporal Modelling of Socio-Economic Wildfire Drivers in Central Spain between the 1980s and the 2000s: Comparing Generalized Linear Models to Machine Learning Algorithms.

Science.gov (United States)

Vilar, Lara; Gómez, Israel; Martínez-Vega, Javier; Echavarría, Pilar; Riaño, David; Martín, M Pilar

2016-01-01

The socio-economic factors are of key importance during all phases of wildfire management that include prevention, suppression and restoration. However, modeling these factors, at the proper spatial and temporal scale to understand fire regimes is still challenging. This study analyses socio-economic drivers of wildfire occurrence in central Spain. This site represents a good example of how human activities play a key role over wildfires in the European Mediterranean basin. Generalized Linear Models (GLM) and machine learning Maximum Entropy models (Maxent) predicted wildfire occurrence in the 1980s and also in the 2000s to identify changes between each period in the socio-economic drivers affecting wildfire occurrence. GLM base their estimation on wildfire presence-absence observations whereas Maxent on wildfire presence-only. According to indicators like sensitivity or commission error Maxent outperformed GLM in both periods. It achieved a sensitivity of 38.9% and a commission error of 43.9% for the 1980s, and 67.3% and 17.9% for the 2000s. Instead, GLM obtained 23.33, 64.97, 9.41 and 18.34%, respectively. However GLM performed steadier than Maxent in terms of the overall fit. Both models explained wildfires from predictors such as population density and Wildland Urban Interface (WUI), but differed in their relative contribution. As a result of the urban sprawl and an abandonment of rural areas, predictors like WUI and distance to roads increased their contribution to both models in the 2000s, whereas Forest-Grassland Interface (FGI) influence decreased. This study demonstrates that human component can be modelled with a spatio-temporal dimension to integrate it into wildfire risk assessment.

EXPERIMENTS AND COMPUTATIONAL MODELING OF PULVERIZED-COAL IGNITION; FINAL

International Nuclear Information System (INIS)

Samuel Owusu-Ofori; John C. Chen

1999-01-01

Under typical conditions of pulverized-coal combustion, which is characterized by fine particles heated at very high rates, there is currently a lack of certainty regarding the ignition mechanism of bituminous and lower rank coals as well as the ignition rate of reaction. furthermore, there have been no previous studies aimed at examining these factors under various experimental conditions, such as particle size, oxygen concentration, and heating rate. Finally, there is a need to improve current mathematical models of ignition to realistically and accurately depict the particle-to-particle variations that exist within a coal sample. Such a model is needed to extract useful reaction parameters from ignition studies, and to interpret ignition data in a more meaningful way. The authors propose to examine fundamental aspects of coal ignition through (1) experiments to determine the ignition temperature of various coals by direct measurement, and (2) modeling of the ignition process to derive rate constants and to provide a more insightful interpretation of data from ignition experiments. The authors propose to use a novel laser-based ignition experiment to achieve their first objective. Laser-ignition experiments offer the distinct advantage of easy optical access to the particles because of the absence of a furnace or radiating walls, and thus permit direct observation and particle temperature measurement. The ignition temperature of different coals under various experimental conditions can therefore be easily determined by direct measurement using two-color pyrometry. The ignition rate-constants, when the ignition occurs heterogeneously, and the particle heating rates will both be determined from analyses based on these measurements

Definition of Ignition in Inertial Confinement Fusion

Science.gov (United States)

Christopherson, A. R.; Betti, R.

2017-10-01

Defining ignition in inertial confinement fusion (ICF) is an unresolved problem. In ICF, a distinction must be made between the ignition of the hot spot and the propagation of the burn wave in the surrounding dense fuel. Burn propagation requires that the hot spot is robustly ignited and the dense shell exhibits enough areal density. Since most of the energy gain comes from burning the dense shell, in a scale of increasing yields, hot-spot ignition comes before high gains. Identifying this transition from hot-spot ignition to burn-wave propagation is key to defining ignition in general terms applicable to all fusion approaches that use solid DT fuel. Ad hoc definitions such as gain = 1 or doubling the temperature are not generally valid. In this work, we show that it is possible to identify the onset of ignition through a unique value of the yield amplification defined as the ratio of the fusion yield including alpha-particle deposition to the fusion yield without alphas. Since the yield amplification is a function of the fractional alpha energy fα =EαEα 2Ehs 2Ehs (a measurable quantity), it appears possible not only to define ignition but also to measure the onset of ignition by the experimental inference of the fractional alpha energy and yield amplification. This material is based upon work supported by the Department of Energy Office of Fusion Energy Services under Award Number DE-FC02-04ER54789 and National Nuclear Security Administration under Award Number DE-NA0001944.

Effects of forest management on California Spotted Owls: implications for reducing wildfire risk in fire‐prone forests.

Science.gov (United States)

Tempel, Douglas J; Gutiérrez, R J; Whitmore, Sheila A; Reetz, Matthew J; Stoelting, Ricka E; Berigan, William J; Seamans, Mark E; Zachariah Peery, M

Management of many North American forests is challenged by the need to balance the potentially competing objectives of reducing risks posed by high-severity wildfires and protecting threatened species. In the Sierra Nevada, California, concern about high-severity fires has increased in recent decades but uncertainty exists over the effects of fuel-reduction treatments on species associated with older forests, such as the California Spotted Owl (Strix occidentalis occidentalis). Here, we assessed the effects of forest conditions, fuel reductions, and wildfire on a declining population of Spotted Owls in the central Sierra Nevada using 20 years of demographic data collected at 74 Spotted Owl territories. Adult survival and territory colonization probabilities were relatively high, while territory extinction probability was relatively low, especially in territories that had relatively large amounts of high canopy cover (≥70%) forest. Reproduction was negatively associated with the area of medium-intensity timber harvests characteristic of proposed fuel treatments. Our results also suggested that the amount of edge between older forests and shrub/sapling vegetation and increased habitat heterogeneity may positively influence demographic rates of Spotted Owls. Finally, high-severity fire negatively influenced the probability of territory colonization. Despite correlations between owl demographic rates and several habitat variables, life stage simulation (sensitivity) analyses indicated that the amount of forest with high canopy cover was the primary driver of population growth and equilibrium occupancy at the scale of individual territories. Greater than 90% of medium-intensity harvests converted high-canopy-cover forests into lower-canopy-cover vegetation classes, suggesting that landscape-scale fuel treatments in such stands could have short-term negative impacts on populations of California Spotted Owls. Moreover, high-canopy-cover forests declined by an average of

Study of ignition in a high compression ratio SI (spark ignition) methanol engine using LES (large eddy simulation) with detailed chemical kinetics

International Nuclear Information System (INIS)

Zhen, Xudong; Wang, Yang

2013-01-01

Methanol has been recently used as an alternative to conventional fuels for internal combustion engines in order to satisfy some environmental and economical concerns. In this paper, the ignition in a high compression ratio SI (spark ignition) methanol engine was studied by using LES (large eddy simulation) with detailed chemical kinetics. A 21-species, 84-reaction methanol mechanism was adopted to simulate the auto-ignition process of the methanol/air mixture. The MIT (minimum ignition temperature) and MIE (minimum ignition energy) are two important properties for designing safety standards and understanding the ignition process of combustible mixtures. The effects of the flame kernel size, flame kernel temperature and equivalence ratio were also examined on MIT, MIE and IDP (ignition delay period). The methanol mechanism was validated by experimental test. The simulated results showed that the flame kernel size, temperature and energy dramatically affected the values of the MIT, MIE and IDP for a methanol/air mixture, the value of the ignition delay period was not only related to the flame kernel energy, but also to the flame kernel temperature. - Highlights: • We used LES (large eddy simulation) coupled with detailed chemical kinetics to simulate methanol ignition. • The flame kernel size and temperature affected the minimum ignition temperature. • The flame kernel temperature and energy affected the ignition delay period. • The equivalence ratio of methanol–air mixture affected the ignition delay period

A sustained-arc ignition system for internal combustion engines

Science.gov (United States)

Birchenough, A. G.

1977-01-01

A sustained-arc ignition system was developed for internal combustion engines. It produces a very-long-duration ignition pulse with an energy in the order of 100 millijoules. The ignition pulse waveform can be controlled to predetermined actual ignition requirements. The design of the sustained-arc ignition system is presented in the report.

Science You Can Use Bulletin: Wildfire triage: Targeting mitigation based on social, economic, and ecological values

Science.gov (United States)

Karl Malcolm; Matthew Thompson; Dave Calkin; Mark Finney; Alan Ager

2012-01-01

Evaluating the risks of wildfire relative to the valuable resources found in any managed landscape requires an interdisciplinary approach. Researchers at the Rocky Mountain Research Station and Western Wildland Threat Assessment Center developed such a process, using a combination of techniques rooted in fire modeling and ecology, economics, decision sciences, and the...

Chemical Kinetics of Hydrocarbon Ignition in Practical Combustion Systems

International Nuclear Information System (INIS)

Westbrook, C.K.

2000-01-01

Chemical kinetic factors of hydrocarbon oxidation are examined in a variety of ignition problems. Ignition is related to the presence of a dominant chain branching reaction mechanism that can drive a chemical system to completion in a very short period of time. Ignition in laboratory environments is studied for problems including shock tubes and rapid compression machines. Modeling of the laboratory systems are used to develop kinetic models that can be used to analyze ignition in practical systems. Two major chain branching regimes are identified, one consisting of high temperature ignition with a chain branching reaction mechanism based on the reaction between atomic hydrogen with molecular oxygen, and the second based on an intermediate temperature thermal decomposition of hydrogen peroxide. Kinetic models are then used to describe ignition in practical combustion environments, including detonations and pulse combustors for high temperature ignition, and engine knock and diesel ignition for intermediate temperature ignition. The final example of ignition in a practical environment is homogeneous charge, compression ignition (HCCI) which is shown to be a problem dominated by the kinetics intermediate temperature hydrocarbon ignition. Model results show why high hydrocarbon and CO emissions are inevitable in HCCI combustion. The conclusion of this study is that the kinetics of hydrocarbon ignition are actually quite simple, since only one or two elementary reactions are dominant. However, there are many combustion factors that can influence these two major reactions, and these are the features that vary from one practical system to another

Rating a Wildfire Mitigation Strategy with an Insurance Premium: A Boreal Forest Case Study

Directory of Open Access Journals (Sweden)

Georgina Rodriguez-Baca

2016-05-01

Full Text Available Risk analysis entails the systematic use of historical information to determine the frequency, magnitude and effects of unexpected events. Wildfire in boreal North America is a key driver of forest dynamics and may cause very significant economic losses. An actuarial approach to risk analysis based on cumulative probability distributions was developed to reduce the adverse effects of wildfire. To this effect, we developed spatially explicit landscape models to simulate the interactions between harvest, fire and forest succession over time in a boreal forest of eastern Canada. We estimated the amount of reduction of timber harvest necessary to build a buffer stock of sufficient size to cover fire losses and compared it to an insurance premium estimated in units of timber volume from the probability of occurrence and the amount of damage. Overall, the timber harvest reduction we applied was much more costly than the insurance premium even with a zero interest rate. This is due to the fact that the insurance premium is directly related to risk while the timber harvest reduction is not and, as a consequence, is much less efficient. These results, especially the comparison with a standard indicator such as an insurance premium, have useful implications at the time of choosing a mitigation strategy to protect timber supplies against risk without overly diminishing the provision of services from the forest. They are also promoting the use of insurance against disastrous events in forest management planning.

Ignition and spread of electrical wire fires

OpenAIRE

Huang, Xinyan

2012-01-01

Ignition of electrical wires by external heating is investigated in order to gain a better understanding of the initiation of electrical-wire fires. An ignition-to- spread model is developed to systematically explain ignition and the following transition to spread. The model predicts that for a higher-conductance wire it is more difficult to achieve ignition and the weak flame may extinguish during the transition phase because of a large conductive heat loss along the wire core. Wires with tw...

Ignition experiment - alternatives

International Nuclear Information System (INIS)

Knobloch, A.F.

1979-10-01

This report comprises three short papers on cost estimates, integral burn time and alternative versions of Tokamak ignition experiments. These papers were discussed at the ZEPHYR workshop with participants from IPP Garching, MIT Cambridge and PPPL Princeton (Garching July 30 - August 2 1979) (Chapters A, B, C). It is shown, that starting from a practical parameter independent minimum integral burn time of Tokamak ignition experiments (some 10 3 s) by adding a shield for protection of the magnet insulation (permitted neutron dose 10 9 rad) an integral burn time of some 10 4 s can be achieved for only about 30% more outlay. For a substantially longer integral burn time the outlay approaches rather quickly that for a Tokamak reactor. Some examples for alternatives to ZEPHYR are being given, including some with low or no compression. In a further chapter D some early results of evaluating an ignition experiment on the basis of the energy confinement scaling put forward by Coppi and Mazzucato are presented. As opposed to the case of the Alcator scaling used in chapters A through C the minimum integral burn time of Tokamak ignition experiments here depends on the plasma current. Provided neutral injectors up to about 160 keV are available compression boosting is not required with this scaling. The results presented have been obtained neglecting the effects of the toroidal field ripple. (orig.) 891 HT/orig. 892 RKD [de

Electronic ignition system for internal combustion engines

Energy Technology Data Exchange (ETDEWEB)

Crowder, L W

1980-11-20

Mechanical ignition adjustment devices are sensitive to many effects, for example breakage, faults due to manufacturing tolerances, play in the linkage and the effect of a dirty or corrosive environment. It is therefore the purpose of the invention to provide an electronic ignition system which avoids the disadvantages of a mechanical system. The invention provides adjustment of the ignition point, which gives advance of the ignition timing with increasing speed. An output signal is formed, which supersedes the signal supplied by the electronic control system, so that the ignition is advanced. This also occurs with a larger crankshaft angle before top dead centre of the engine. The electronic control system combines with a source of AC time signals which has a generator as electrical transmitter and a DC battery and ignition coil. The rotor of the electrical generator is driven synchronised with the engine. Structural and functional details of the transistor control circuits are given in 5 patent claims.

THE APPLICATION FOR A PREDICTION OF THE COAL SPONTANEOUS IGNITION – PREDISAM

Directory of Open Access Journals (Sweden)

Vlastimil MONI

2017-04-01

Full Text Available The article follows the research of the project number TA01020351 called “The research of possibilities when predicting steam origin and consequent spontaneous ignition of brown coal fuels” which was researched with the support of the Technological Agency in the Czech Republic in 2011-2014 in the connection with a realized technical research. Therefore, it gives a summary information about the evaluation of the risk degree for the origin of spontaneous ignitions of the brown coal. The presented way of evaluation is based on a numeric expression of a value for MHU criteria – the point load of particular indicators is added together with other results gained from this research project. Then, more information is taken from companies running the dumps of brown coal products – both for suppliers (mining companies and big consumers (power engineering. The complex knowledge about prediction of the origin of the spontaneous ignition enables to make an early response to eliminate a threat of mining fire in open pit mines or on the dumps of coal products. Consequently, it reduces the risk of fire and breakdowns of transportation means DPD, heavy machines and preparation plants. The working injuries are reduced as well – burns by coal in fire or inhalation of gas products from imperfect combustion.

Ignition of mercury-free high intensity discharge lamps

International Nuclear Information System (INIS)

Czichy, M; Mentel, J; Awakowicz, P; Hartmann, T

2008-01-01

To achieve a better understanding of the ignition behaviour of D4 lamps for automotive headlights the ignition of mercury-free metal iodide test lamps characterized by a high xenon pressure, a small electrode distance and small electrode-wall distances is investigated. The ignition of these lamps is dominated by a high voltage requirement. Nevertheless lamps are found that show a surprisingly low ignition voltage. Electrical measurements and simultaneous optical observations of the ultra-fast streamer processes show that the breakdown takes place in two different modes. One of the ignition modes which requires a high ignition voltage is characterized by a breakdown in the volume between the electrode tips. The other mode is characterized by streamer discharges along the wall. In this case the cathode, its base and the wall around is involved in the ignition process and the lamp breaks down at low voltages

The IGNITE network: a model for genomic medicine implementation and research.

Science.gov (United States)

Weitzel, Kristin Wiisanen; Alexander, Madeline; Bernhardt, Barbara A; Calman, Neil; Carey, David J; Cavallari, Larisa H; Field, Julie R; Hauser, Diane; Junkins, Heather A; Levin, Phillip A; Levy, Kenneth; Madden, Ebony B; Manolio, Teri A; Odgis, Jacqueline; Orlando, Lori A; Pyeritz, Reed; Wu, R Ryanne; Shuldiner, Alan R; Bottinger, Erwin P; Denny, Joshua C; Dexter, Paul R; Flockhart, David A; Horowitz, Carol R; Johnson, Julie A; Kimmel, Stephen E; Levy, Mia A; Pollin, Toni I; Ginsburg, Geoffrey S

2016-01-05

Patients, clinicians, researchers and payers are seeking to understand the value of using genomic information (as reflected by genotyping, sequencing, family history or other data) to inform clinical decision-making. However, challenges exist to widespread clinical implementation of genomic medicine, a prerequisite for developing evidence of its real-world utility. To address these challenges, the National Institutes of Health-funded IGNITE (Implementing GeNomics In pracTicE; www.ignite-genomics.org ) Network, comprised of six projects and a coordinating center, was established in 2013 to support the development, investigation and dissemination of genomic medicine practice models that seamlessly integrate genomic data into the electronic health record and that deploy tools for point of care decision making. IGNITE site projects are aligned in their purpose of testing these models, but individual projects vary in scope and design, including exploring genetic markers for disease risk prediction and prevention, developing tools for using family history data, incorporating pharmacogenomic data into clinical care, refining disease diagnosis using sequence-based mutation discovery, and creating novel educational approaches. This paper describes the IGNITE Network and member projects, including network structure, collaborative initiatives, clinical decision support strategies, methods for return of genomic test results, and educational initiatives for patients and providers. Clinical and outcomes data from individual sites and network-wide projects are anticipated to begin being published over the next few years. The IGNITE Network is an innovative series of projects and pilot demonstrations aiming to enhance translation of validated actionable genomic information into clinical settings and develop and use measures of outcome in response to genome-based clinical interventions using a pragmatic framework to provide early data and proofs of concept on the utility of these

How can investment in the landscape or the interface reduce the risk of house loss from wildfires? A comparative study between Sydney, Australia and California, USA

Science.gov (United States)

Penman, Trent; Bradstock, Ross; Collins, Luke; Fotheringham, Cj; Keeley, Jon; Labiosa, Bill; Price, Owen; Syphard, Alex

2013-04-01

Wildfire can result in significant losses to people and property. Management agencies undertake a range of actions in the landscape and at the interface to reduce this risk. Data relating to the success of individual treatments varies, with some approaches well understood and others less so. Research has rarely attempted to consider the interactive effects of treatments in order to determine optimal management strategies that reduce the risk of loss. Bayesian Networks provide a statistical framework for undertaking such an analysis. Here we apply Bayesian Networks to examine the trade-offs in investment in preventative actions (e.g., fuel treatment, community education, development controls) and suppressive actions (e.g., initial attack, landscape suppression, property protection) in two fire prone regions -Sydney, Australia and California, USA. Investment in management actions at the interface resulted in the greatest reduction in the risk of house loss for both of the study regions. Landscape treatments had a limited ability to change the risk of house loss.

Proton Fast Ignition

International Nuclear Information System (INIS)

Key, M H; Freeman, R R; Hatchett, S P; MacKinnon, A J; Patel, P K; Snavely, R A; Stephens, R B

2006-04-01

Fast ignition (FI) by a laser generated ballistically focused proton beam is a more recently proposed alternative to the original concept of FI by a laser generated beam of relativistic electrons. It has potential advantages in less complex energy transport into dense plasma. Recent successful target heating experiments motivate further investigation of the feasibility of proton fast ignition. The concept, the physics and characteristics of the proton beams, the recent experimental work on focusing of the beams and heating of solid targets and the overall prospects for proton FI are discussed

Review of the National Ignition Campaign 2009-2012

International Nuclear Information System (INIS)

Lindl, John; Landen, Otto; Edwards, John; Moses, Ed

2014-01-01

The National Ignition Campaign (NIC) was a multi-institution effort established under the National Nuclear Security Administration of DOE in 2005, prior to the completion of the National Ignition Facility (NIF) in 2009. The scope of the NIC was the planning and preparation for and the execution of the first 3 yr of ignition experiments (through the end of September 2012) as well as the development, fielding, qualification, and integration of the wide range of capabilities required for ignition. Besides the operation and optimization of the use of NIF, these capabilities included over 50 optical, x-ray, and nuclear diagnostic systems, target fabrication facilities, experimental platforms, and a wide range of NIF facility infrastructure. The goal of ignition experiments on the NIF is to achieve, for the first time, ignition and thermonuclear burn in the laboratory via inertial confinement fusion and to develop a platform for ignition and high energy density applications on the NIF. The goal of the NIC was to develop and integrate all of the capabilities required for a precision ignition campaign and, if possible, to demonstrate ignition and gain by the end of FY12. The goal of achieving ignition can be divided into three main challenges. The first challenge is defining specifications for the target, laser, and diagnostics with the understanding that not all ignition physics is fully understood and not all material properties are known. The second challenge is designing experiments to systematically remove these uncertainties. The third challenge is translating these experimental results into metrics designed to determine how well the experimental implosions have performed relative to expectations and requirements and to advance those metrics toward the conditions required for ignition. This paper summarizes the approach taken to address these challenges, along with the progress achieved to date and the challenges that remain. At project completion in 2009, NIF lacked

Short-wavelength and three-dimensional instability evolution in National Ignition Facility ignition capsule designs

International Nuclear Information System (INIS)

Clark, D. S.; Haan, S. W.; Cook, A. W.; Edwards, M. J.; Hammel, B. A.; Koning, J. M.; Marinak, M. M.

2011-01-01

Ignition capsule designs for the National Ignition Facility (NIF) [G. H. Miller, E. I. Moses, and C. R. Wuest, Opt. Eng. 443, 2841 (2004)] have continued to evolve in light of improved physical data inputs, improving simulation techniques, and, most recently, experimental data from a growing number of NIF sub-ignition experiments. This paper summarizes a number of recent changes to the cryogenic capsule design and some of our latest techniques in simulating its performance. Specifically, recent experimental results indicated harder x-ray drive spectra in NIF hohlraums than were predicted and used in previous capsule optimization studies. To accommodate this harder drive spectrum, a series of high-resolution 2-D simulations, resolving Legendre mode numbers as high as 2000, were run and the germanium dopant concentration and ablator shell thicknesses re-optimized accordingly. Simultaneously, the possibility of cooperative or nonlinear interaction between neighboring ablator surface defects has motivated a series of fully 3-D simulations run with the massively parallel HYDRA code. These last simulations include perturbations seeded on all capsule interfaces and can use actual measured shell surfaces as initial conditions. 3-D simulations resolving Legendre modes up to 200 on large capsule sectors have run through ignition and burn, and higher resolution simulations resolving as high as mode 1200 have been run to benchmark high-resolution 2-D runs. Finally, highly resolved 3-D simulations have also been run of the jet-type perturbation caused by the fill tube fitted to the capsule. These 3-D simulations compare well with the more typical 2-D simulations used in assessing the fill tube's impact on ignition. Coupled with the latest experimental inputs from NIF, our improving simulation capability yields a fuller and more accurate picture of NIF ignition capsule performance.

Electron Shock Ignition of Inertial Fusion Targets

International Nuclear Information System (INIS)

Shang, W. L.; Betti, R.; Hu, S. X.; Woo, K.; Hao, L.

2017-01-01

Here, it is shown that inertial fusion targets designed with low implosion velocities can be shock ignited using laser–plasma interaction generated hot electrons (hot-e) to obtain high-energy gains. These designs are robust to multimode asymmetries and are predicted to ignite even for significantly distorted implosions. Electron shock ignition requires tens of kilojoules of hot-e, which can only be produced on a large laser facility like the National Ignition Facility, with the laser to hot-e conversion efficiency greater than 10% at laser intensities ~10 16 W/cm 2 .

Development of a pre-ignition submodel for hydrogen engines

Energy Technology Data Exchange (ETDEWEB)

Al-Baghdadi, Sadiq [University of Babylon (Iraq). Dept. of Mechanical Engineering

2005-10-15

In hydrogen-fuelled spark ignition engine applications, the onset of pre-ignition remains one of the prime limitations that needs to be addressed to avoid its incidence and achieve superior performance. This paper describes a new pre-ignition submodel for engine modelling codes. The effects of changes in key operating variables, such as compression ratio, spark timing, intake pressure, and temperature on pre-ignition limiting equivalence ratios are established both analytically and experimentally. With the established pre-ignition model, it is possible not only to investigate whether pre-ignition is observed with changing operating and design parameters, but also to evaluate those parameters' effects on the maximum possible pre-ignition intensity. (author)

3rd Conference on Ignition Systems for Gasoline Engines

CERN Document Server

Sens, Marc

2017-01-01

The volume includes selected and reviewed papers from the 3rd Conference on Ignition Systems for Gasoline Engines in Berlin in November 2016. Experts from industry and universities discuss in their papers the challenges to ignition systems in providing reliable, precise ignition in the light of a wide spread in mixture quality, high exhaust gas recirculation rates and high cylinder pressures. Classic spark plug ignition as well as alternative ignition systems are assessed, the ignition system being one of the key technologies to further optimizing the gasoline engine.

Fire regimes approaching historic norms reduce wildfire-facilitated conversion from forest to non-forest

Science.gov (United States)

Ryan B. Walker; Jonathan D. Coop; Sean A. Parks; Laura Trader

2018-01-01

Extensive high-severity wildfires have driven major losses of ponderosa pine and mixed-conifer forests in the southwestern United States, in some settings catalyzing enduring conversions to nonforested vegetation types. Management interventions to reduce the probability of stand-replacing wildfire have included mechanical fuel treatments, prescribed fire, and wildfire...

Modern Approaches to Wildfire Mitigation by Air and by Ground: An Interdisciplinary Perspective

Science.gov (United States)

Duffin, J.; Lindquist, E.; Pierce, J. L.; Wuerzer, T.; Lawless, B.; McCoy, J.

2013-12-01

In 2012, 1.7 million acres of land burned in Idaho--more than any other state. Boise, Idaho, is situated at the base of the Boise Foothills; this physiographic setting places the area at risk of not only fires along on the Wildland-Urban Interface (WUI), but also at risk for post-fire floods and debris flows in the lower lying neighborhoods adjacent to steep hillslopes. In 1959 and 1994, fires and post-fire debris flows devastated areas of the foothills, and inundated residences with water and mud. Anthropogenically-induced climate change is projected to increased summer temperatures and decrease summer precipitation; the associated increase in fire risk necessitates enhanced wildfire planning in Boise's WUI. Temporal uncertainty with varying weather and vegetation conditions poses problems in defining wildfire risk and requires new methods to address the WUI challenges. Unmanned aerial systems (UAS) could identify and characterize fire hazards to be mapped and used as a management tool. This technology would allow for repeat flights to update risk analysis as the hazards change both annually and multiple times within each fire season. With aerial photography obtained from flights, Structure from Motion software can be used to compile the images and render a 3D model to help quantify biomass. Aerial photographs would also allow for the ability to track seasonal changes in fire risk from vegetation height and inferred moisture content. Boise State University's departments of Geoscience, Community and Regional Planning, and the Public Policy Center are examining the risks and impacts of fire along the Boise WUI. The research integrates the perspectives of the geosciences and social sciences by combining physically-based fire hazards, effective fire management policies, and urban/regional planning in the WUI to provide better spatially-appropriate data and resources to the community and a common reference to assist in unifying the local efforts for fire mitigation

Difference in information needs for wildfire evacuees and non-evacuees

Science.gov (United States)

Sarah M. McCaffrey; Anne-Lise Knox Velez; Jason Alexander. Briefel

2013-01-01

This paper examines whether evacuees from two wildfires displayed different information seeking behavior than non-evacuees. Findings are the results of a mail survey sent to residents affected by wildfires outside Flagstaff, Arizona and Boulder, Colorado in 2010. We found evacuees sought information more actively than non-evacuees and placed a greater emphasis on use...

Avian relationships with wildfire at two dry forest locations with different historical fire regimes

Science.gov (United States)

Quresh Latif; Jamie Sanderlin; Vicki Saab; William Block; Jonathan Dudley

2016-01-01

Wildfire is a key factor influencing bird community composition in western North American forests. We need to understand species and community responses to wildfire and how responses vary regionally to effectively manage dry conifer forests for maintaining biodiversity. We compared avian relationships with wildfire burn severity between two dry forest...

Theory of hydro-equivalent ignition for inertial fusion and its applications to OMEGA and the National Ignition Facility

Energy Technology Data Exchange (ETDEWEB)

Nora, R.; Betti, R.; Bose, A.; Woo, K. M.; Christopherson, A. R.; Meyerhofer, D. D. [Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623-1299 (United States); Fusion Science Center, University of Rochester, 250 East River Road, Rochester, New York 14623-1299 (United States); Department of Physics and/or Mechanical Engineering, University of Rochester, 250 East River Road, Rochester, New York 14623-1299 (United States); Anderson, K. S.; Shvydky, A.; Marozas, J. A.; Collins, T. J. B.; Radha, P. B.; Hu, S. X.; Epstein, R.; Marshall, F. J.; Sangster, T. C. [Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623-1299 (United States); McCrory, R. L. [Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623-1299 (United States); Department of Physics and/or Mechanical Engineering, University of Rochester, 250 East River Road, Rochester, New York 14623-1299 (United States)

2014-05-15

The theory of ignition for inertial confinement fusion capsules [R. Betti et al., Phys. Plasmas 17, 058102 (2010)] is used to assess the performance requirements for cryogenic implosion experiments on the Omega Laser Facility. The theory of hydrodynamic similarity is developed in both one and two dimensions and tested using multimode hydrodynamic simulations with the hydrocode DRACO [P. B. Radha et al., Phys. Plasmas 12, 032702 (2005)] of hydro-equivalent implosions (implosions with the same implosion velocity, adiabat, and laser intensity). The theory is used to scale the performance of direct-drive OMEGA implosions to the National Ignition Facility (NIF) energy scales and determine the requirements for demonstrating hydro-equivalent ignition on OMEGA. Hydro-equivalent ignition on OMEGA is represented by a cryogenic implosion that would scale to ignition on the NIF at 1.8 MJ of laser energy symmetrically illuminating the target. It is found that a reasonable combination of neutron yield and areal density for OMEGA hydro-equivalent ignition is 3 to 6 × 10{sup 13} and ∼0.3 g/cm{sup 2}, respectively, depending on the level of laser imprinting. This performance has not yet been achieved on OMEGA.

Theory of hydro-equivalent ignition for inertial fusion and its applications to OMEGA and the National Ignition Facility

International Nuclear Information System (INIS)

Nora, R.; Betti, R.; Bose, A.; Woo, K. M.; Christopherson, A. R.; Meyerhofer, D. D.; Anderson, K. S.; Shvydky, A.; Marozas, J. A.; Collins, T. J. B.; Radha, P. B.; Hu, S. X.; Epstein, R.; Marshall, F. J.; Sangster, T. C.; McCrory, R. L.

2014-01-01

The theory of ignition for inertial confinement fusion capsules [R. Betti et al., Phys. Plasmas 17, 058102 (2010)] is used to assess the performance requirements for cryogenic implosion experiments on the Omega Laser Facility. The theory of hydrodynamic similarity is developed in both one and two dimensions and tested using multimode hydrodynamic simulations with the hydrocode DRACO [P. B. Radha et al., Phys. Plasmas 12, 032702 (2005)] of hydro-equivalent implosions (implosions with the same implosion velocity, adiabat, and laser intensity). The theory is used to scale the performance of direct-drive OMEGA implosions to the National Ignition Facility (NIF) energy scales and determine the requirements for demonstrating hydro-equivalent ignition on OMEGA. Hydro-equivalent ignition on OMEGA is represented by a cryogenic implosion that would scale to ignition on the NIF at 1.8 MJ of laser energy symmetrically illuminating the target. It is found that a reasonable combination of neutron yield and areal density for OMEGA hydro-equivalent ignition is 3 to 6 × 10 13 and ∼0.3 g/cm 2 , respectively, depending on the level of laser imprinting. This performance has not yet been achieved on OMEGA

Low power arcjet thruster pulse ignition

Science.gov (United States)

Sarmiento, Charles J.; Gruber, Robert P.

1987-01-01

An investigation of the pulse ignition characteristics of a 1 kW class arcjet using an inductive energy storage pulse generator with a pulse width modulated power converter identified several thruster and pulse generator parameters that influence breakdown voltage including pulse generator rate of voltage rise. This work was conducted with an arcjet tested on hydrogen-nitrogen gas mixtures to simulate fully decomposed hydrazine. Over all ranges of thruster and pulser parameters investigated, the mean breakdown voltages varied from 1.4 to 2.7 kV. Ignition tests at elevated thruster temperatures under certain conditions revealed occasional breakdowns to thruster voltages higher than the power converter output voltage. These post breakdown discharges sometimes failed to transition to the lower voltage arc discharge mode and the thruster would not ignite. Under the same conditions, a transition to the arc mode would occur for a subsequent pulse and the thruster would ignite. An automated 11 600 cycle starting and transition to steady state test demonstrated ignition on the first pulse and required application of a second pulse only two times to initiate breakdown.

Capsule Performance Optimization in the National Ignition Campaign

Energy Technology Data Exchange (ETDEWEB)

Landen, O L; MacGowan, B J; Haan, S W; Edwards, J

2009-10-13

A capsule performance optimization campaign will be conducted at the National Ignition Facility to substantially increase the probability of ignition. The campaign will experimentally correct for residual uncertainties in the implosion and hohlraum physics used in our radiation-hydrodynamic computational models before proceeding to cryogenic-layered implosions and ignition attempts. The required tuning techniques using a variety of ignition capsule surrogates have been demonstrated at the Omega facility under scaled hohlraum and capsule conditions relevant to the ignition design and shown to meet the required sensitivity and accuracy. In addition, a roll-up of all expected random and systematic uncertainties in setting the key ignition laser and target parameters due to residual measurement, calibration, cross-coupling, surrogacy, and scale-up errors has been derived that meets the required budget.

Capsule performance optimization in the national ignition campaign

International Nuclear Information System (INIS)

Landen, O L; MacGowan, B J; Haan, S W; Edwards, J

2010-01-01

A capsule performance optimization campaign will be conducted at the National Ignition Facility [1] to substantially increase the probability of ignition. The campaign will experimentally correct for residual uncertainties in the implosion and hohlraum physics used in our radiation-hydrodynamic computational models before proceeding to cryogenic-layered implosions and ignition attempts. The required tuning techniques using a variety of ignition capsule surrogates have been demonstrated at the Omega facility under scaled hohlraum and capsule conditions relevant to the ignition design and shown to meet the required sensitivity and accuracy. In addition, a roll-up of all expected random and systematic uncertainties in setting the key ignition laser and target parameters due to residual measurement, calibration, cross-coupling, surrogacy, and scale-up errors has been derived that meets the required budget.

Capsule performance optimization in the national ignition campaign

Science.gov (United States)

Landen, O. L.; MacGowan, B. J.; Haan, S. W.; Edwards, J.

2010-08-01

A capsule performance optimization campaign will be conducted at the National Ignition Facility [1] to substantially increase the probability of ignition. The campaign will experimentally correct for residual uncertainties in the implosion and hohlraum physics used in our radiation-hydrodynamic computational models before proceeding to cryogenic-layered implosions and ignition attempts. The required tuning techniques using a variety of ignition capsule surrogates have been demonstrated at the Omega facility under scaled hohlraum and capsule conditions relevant to the ignition design and shown to meet the required sensitivity and accuracy. In addition, a roll-up of all expected random and systematic uncertainties in setting the key ignition laser and target parameters due to residual measurement, calibration, cross-coupling, surrogacy, and scale-up errors has been derived that meets the required budget.

Influence of several factors on ignition lag in a compression-ignition engine

Science.gov (United States)

Gerrish, Harold C; Voss, Fred

1932-01-01

This investigation was made to determine the influence of fuel quality, injection advance angle, injection valve-opening pressure, inlet-air pressure, compression ratio, and engine speed on the time lag of auto-ignition of a Diesel fuel oil in a single-cylinder compression-ignition engine as obtained from an analysis of indicator diagrams. Three cam-operated fuel-injection pumps, two pumps cams, and an automatic injection valve with two different nozzles were used. Ignition lag was considered to be the interval between the start of injection of the fuel as determined with a Stroborama and the start of effective combustion as determined from the indicator diagram, the latter being the point where 4.0 x 10(exp-6) pound of fuel had been effectively burned. For this particular engine and fuel it was found that: (1) for a constant start and the same rate of fuel injection up the point of cut-off, a variation in fuel quantity from 1.2 x 10(exp-4) to 4.1 x 10(exp-4) pound per cycle has no appreciable effect on the ignition lag; (2) injection advance angle increases or decreases the lag according to whether density, temperature, or turbulence has the controlling influence; (3) increase in valve-opening pressure slightly increases the lag; and (4) increase of inlet-air pressure, compression ratio, and engine speed reduces the lag.

The use of tritium rich capsules with 25-35% deuterium to achieve ignition at the National Ignition Facility

Science.gov (United States)

Wilson, D. C.; Spears, B. K.; Hatchett, S. P., Ii; Cerjan, C. J.; Springer, P. T.; Clark, D. S.; Edwards, M. J.; Salmonson, J. D.; Weber, S. V.; Hammel, B. A.; Grim, G. P.; Herrmann, H. W.; Wilke, M. D.

2010-08-01

Diagnostics such as neutron yield, ion temperature, image size and shape, and bang time in capsules with >~25 % deuterium fuel show changes due to burn product heating. The comparison of performance between a THD(2%) and THD(35%) can help predict ignition in a TD(50%) capsule. Surrogacy of THD capsules to TD(50%) is incomplete due to variations in fuel molecular vapour pressures. TD(25-35%) capsules might be preferred to study hot spot heating, but at the risk of increased fuel/ablator mixing.

The use of tritium rich capsules with 25-35% deuterium to achieve ignition at the National Ignition Facility

International Nuclear Information System (INIS)

Wilson, D C; Grim, G P; Herrmann, H W; Wilke, M D; Spears, B K; Ii, S P Hatchett; Cerjan, C J; Springer, P T; Clark, D S; Edwards, M J; Salmonson, J D; Weber, S V; Hammel, B A

2010-01-01

Diagnostics such as neutron yield, ion temperature, image size and shape, and bang time in capsules with >∼25 % deuterium fuel show changes due to burn product heating. The comparison of performance between a THD(2%) and THD(35%) can help predict ignition in a TD(50%) capsule. Surrogacy of THD capsules to TD(50%) is incomplete due to variations in fuel molecular vapour pressures. TD(25-35%) capsules might be preferred to study hot spot heating, but at the risk of increased fuel/ablator mixing.

The use of tritium rich capsules with 25-35% deuterium to achieve ignition at the National Ignition Facility

Energy Technology Data Exchange (ETDEWEB)

Wilson, D C; Grim, G P; Herrmann, H W; Wilke, M D [Los Alamos National Laboratory, Los Alamos, NM, 87545 (United States); Spears, B K; Ii, S P Hatchett; Cerjan, C J; Springer, P T; Clark, D S; Edwards, M J; Salmonson, J D; Weber, S V; Hammel, B A, E-mail: dcw@lanl.go [Lawrence Livermore National Laboratory, Livermore, CA, 94550 (United States)

2010-08-01

Diagnostics such as neutron yield, ion temperature, image size and shape, and bang time in capsules with >{approx}25 % deuterium fuel show changes due to burn product heating. The comparison of performance between a THD(2%) and THD(35%) can help predict ignition in a TD(50%) capsule. Surrogacy of THD capsules to TD(50%) is incomplete due to variations in fuel molecular vapour pressures. TD(25-35%) capsules might be preferred to study hot spot heating, but at the risk of increased fuel/ablator mixing.

Wildfire and aspect effects on hydrologic states after the 2010 Fourmile Canyon Fire

Science.gov (United States)

Ebel, Brian A.

2013-01-01

Wildfire can change how soils take in, store, and release water. This study examined differences in how burned and unburned plots on north versus south-facing slope aspects respond to rainfall. The largest wildfire impacts were litter/duff combustion on burned north-facing slopes versus soil-water retention reduction on burned south-facing slopes.Wildfire is one of the most significant disturbances in mountainous landscapes, affecting water supply and ecologic function and setting the stage for natural hazards such as flash floods. The impacts of wildfire can affect the entire hydrologic cycle. Measurements of soil-water content and matric potential in the near surface (top 30 cm) captured the hydrologic state in both burned and unburned hillslopes during the first spring through fall period (1 June–1 Oct. 2011) after the 2010 Fourmile Canyon Fire near Boulder, CO. This time span included different hydrologic periods characterized by cyclonic frontal storms (low-intensity, long duration), convective storms (high-intensity, short duration), and dry periods. In mountainous environments, aspect can also control hydrologic states, so north- vs. south-facing slopes were compared. Wildfire tended to homogenize soil-water contents across aspects and with depth in the soil, yet it also may have introduced an aspect control on matric potential that was not observed in unburned soils. Post-wildfire changes in hydrologic state were observed in south-facing soils, probably reflecting decreased soil-water retention after wildfire. North-facing soils were impacted the most, in terms of hydrologic state, by the loss of water storage in the combusted litter–duff layer and forest canopy, which had provided a large “hydrologic buffering” capacity when unburned. Unsaturated zone measurements showed increased variability in hydrologic states and more rapid state transitions in wildfire-impacted soils. A simple, qualitative analysis suggested that the range of unsaturated

Smoke consequences of new wildfire regimes driven by climate change

Science.gov (United States)

Donald McKenzie; Uma Shankar; Robert E. Keane; E. Natasha Stavros; Warren E. Heilman; Douglas G. Fox; Allen C. Riebau

2014-01-01

Smoke from wildfires has adverse biological and social consequences, and various lines of evidence suggest that smoke from wildfires in the future may be more intense and widespread, demanding that methods be developed to address its effects on people, ecosystems, and the atmosphere. In this paper, we present the essential ingredients of a modeling system for...

Enhanced Model for Fast Ignition

Energy Technology Data Exchange (ETDEWEB)

Mason, Rodney J. [Research Applications Corporation, Los Alamos, NM (United States)

2010-10-12

Laser Fusion is a prime candidate for alternate energy production, capable of serving a major portion of the nation's energy needs, once fusion fuel can be readily ignited. Fast Ignition may well speed achievement of this goal, by reducing net demands on laser pulse energy and timing precision. However, Fast Ignition has presented a major challenge to modeling. This project has enhanced the computer code ePLAS for the simulation of the many specialized phenomena, which arise with Fast Ignition. The improved code has helped researchers to understand better the consequences of laser absorption, energy transport, and laser target hydrodynamics. ePLAS uses efficient implicit methods to acquire solutions for the electromagnetic fields that govern the accelerations of electrons and ions in targets. In many cases, the code implements fluid modeling for these components. These combined features, "implicitness and fluid modeling," can greatly facilitate calculations, permitting the rapid scoping and evaluation of experiments. ePLAS can be used on PCs, Macs and Linux machines, providing researchers and students with rapid results. This project has improved the treatment of electromagnetics, hydrodynamics, and atomic physics in the code. It has simplified output graphics, and provided new input that avoids the need for source code access by users. The improved code can now aid university, business and national laboratory users in pursuit of an early path to success with Fast Ignition.

Two-stage Lagrangian modeling of ignition processes in ignition quality tester and constant volume combustion chambers

KAUST Repository

Alfazazi, Adamu; Kuti, Olawole Abiola; Naser, Nimal; Chung, Suk-Ho; Sarathy, Mani

2016-01-01

The ignition characteristics of isooctane and n-heptane in an ignition quality tester (IQT) were simulated using a two-stage Lagrangian (TSL) model, which is a zero-dimensional (0-D) reactor network method. The TSL model was also used to simulate

An assessment of two off-shore igniter concepts

International Nuclear Information System (INIS)

Guenette, C. C.

1997-01-01

On June 12, 1996, two controlled in-situ oil spill burns (ISB), using a response-prepared ISB system, were conducted in the North Sea, 40 miles off the U. K. coast. The first burn involved fresh crude oil and was ignited with a hand-held igniter using a standard gelled fuel mixture. In the second burn an emulsified crude was used, ignited with a prototype emulsion breaking igniter (EBI) deployed using the Helitorch. The objective was to determine operational practicalities under realistic conditions when responding to a weathered oil situation in an offshore location. This paper is devoted to an assessment of the two igniter systems used during the trials. Results showed that oil aged by 12 hours with a 25 per cent water content burned down to a three-to-four per cent residue. The fire burn survived the two burns intact. The hand-held ignition system worked with fresh oil and the Helitorch lit emulsified oil using EBI. These trials were the first time that the EBI was deployed from a Helitorch slung beneath a helicopter. It was concluded that (1) the simplicity of the logistics required for the hand-held igniter would favour its use over the Helitorch method for fresh or lightly weathered oil, (2) more heavily weathered oils would require the use of an emulsion-breaking type igniter, and (3) aerial deployment of igniters offer the advantage of allowing more accurate positioning. 10 refs.,5 tabs., 3 figs

Gain curves and hydrodynamic modeling for shock ignition

International Nuclear Information System (INIS)

Lafon, M.; Ribeyre, X.; Schurtz, G.

2010-01-01

Ignition of a precompressed thermonuclear fuel by means of a converging shock is now considered as a credible scheme to obtain high gains for inertial fusion energy. This work aims at modeling the successive stages of the fuel time history, from compression to final thermonuclear combustion, in order to provide the gain curves of shock ignition (SI). The leading physical mechanism at work in SI is pressure amplification, at first by spherical convergence, and by collision with the shock reflected at center during the stagnation process. These two effects are analyzed, and ignition conditions are provided as functions of the shock pressure and implosion velocity. Ignition conditions are obtained from a non-isobaric fuel assembly, for which we present a gain model. The corresponding gain curves exhibit a significantly lower ignition threshold and higher target gains than conventional central ignition.

The 2002 Rodeo-Chediski Wildfire's impacts on southwestern ponderosa pine ecosystems, hydrology, and fuels

Science.gov (United States)

Peter F. Ffolliott; Cody L. Stropki; Hui Chen; Daniel G. Neary

2011-01-01

The Rodeo-Chediski Wildfire burned nearly 462,600 acres in north-central Arizona in the summer of 2002. The wildfire damaged or destroyed ecosystem resources and disrupted the hydrologic functioning within the impacted ponderosa pine (Pinus ponderosa) forests in a largely mosaic pattern. Impacts of the wildfire on ecosystem resources, factors important to hydrologic...

Progress in the indirect-drive National Ignition Campaign

International Nuclear Information System (INIS)

Landen, O L; Benedetti, R; Bleuel, D; Bradley, D K; Caggiano, J A; Callahan, D A; Celliers, P M; Cerjan, C J; Clark, D; Collins, G W; Dewald, E L; Dixit, S N; Doeppner, T; Eggert, J; Farley, D; Glenn, S M; Boehly, T R; Edgell, D; Glebov, V; Frenje, J A

2012-01-01

We have carried out precision optimization of inertial confinement fusion ignition scale implosions. We have achieved hohlraum temperatures in excess of the 300 eV ignition goal with hot-spot symmetry and shock timing near ignition specs. Using slower rise pulses to peak power and extended pulses resulted in lower hot-spot adiabat and higher main fuel areal density at about 80% of the ignition goal. Yields are within a factor of 5–6 of that required to initiate alpha dominated burn. It is likely we will require thicker shells (+15–20%) to reach ignition velocity without mixing of ablator material into the hot spot. (paper)

Re-envisioning community-wildfire relations in the U.S. West as adaptive governance

Directory of Open Access Journals (Sweden)

Jesse B. Abrams

2015-09-01

Full Text Available Prompted by a series of increasingly destructive, expensive, and highly visible wildfire crises in human communities across the globe, a robust body of scholarship has emerged to theorize, conceptualize, and measure community-level resilience to wildfires. To date, however, insufficient consideration has been given to wildfire resilience as a process of adaptive governance mediated by institutions at multiple scales. Here we explore the possibilities for addressing this gap through an analysis of wildfire resilience among wildland-urban interface communities in the western region of the United States. We re-engage important but overlooked components of social-ecological system resilience by situating rural communities within their state- to national-level institutional contexts; we then analyze two communities in Nevada and New Mexico in terms of their institutional settings and responses to recent wildfire events. We frame our analysis around the concepts of scale matching, linking within and across scales, and institutional flexibility.

Laser imprint and implications for direct drive ignition with the National Ignition Facility

International Nuclear Information System (INIS)

Weber, S.V.; Glendinning, S.G.; Kalantar, D.H.; Remington, B.A.; Rothenberg, J.E.

1996-01-01

For direct drive ICF, nonuniformities in laser illumination can seed ripples at the ablation front in a process called imprint. Such nonuniformities will grow during the capsule implosion and can penetrate the capsule shell impede ignition, or degrade burn. We have simulated imprint for a number of experiments on tile Nova laser. Results are in generally good agreement with experimental data. We leave also simulated imprint upon National Ignition Facility (NIF) direct drive ignition capsules. Imprint modulation amplitude comparable to the intrinsic surface finish of ∼40 nm is predicted for a laser bandwidth of 0.5 THz. Ablation front modulations experience growth factors up to several thousand, carrying modulation well into the nonlinear regime. Saturation modeling predicts that the shell should remain intact at the time of peak velocity, but penetration at earlier times appears more marginal

Impacts of Wildfires on Land Surface Phenology of Western US Forests

Science.gov (United States)

Wang, J.; Zhang, X.

2017-12-01

Land surface phenology (LSP) characterizes seasonal dynamics of vegetation communities within a satellite pixel. The temporal variation of LSP has been widely associated with recent global climate change. However, few studies have focused on the influence of land disturbance, such as wildfire, on LSP variations, which is particularly true at a continental scale. Wildfire has increased in size and severity in the western United States (US) during last few decades. To explore wildfire impacts on LSP in the western US forest, we analyzed the start of growing season (SOS) integrated from the entire forest area, the burned area, and the unburned area, respectively. Specifically, SOS was derived from time series of daily MODIS surface reflectance product at 250 m using a hybrid piecewise logistic detection model. The annual burn perimeters during 2000-2014 were obtained from Monitoring Trends in Burn Severity maps to study the wildfire effect on the SOS in the subsequent years (2001-2015). The wildfire effect was analyzed at three levels: the entire western US, Environmental Protection Agency's Level III ecoregions, and states. Results show that wildfires basically advance SOS but have diverse effects with different regions and years. Comparing SOS in the burned areas with that in surrounding unburned areas from 2001-2015, it was found that the SOS shift was -3.4 days (-: earlier; +: later) on average in the western US forests, and varied from -16.1 to 13.1 days across ecoregions and from -11.4 to 4.3 days across states. Because of the small proportion of annual burned areas (SOS shift in the burned areas had limited influences on the overall SOS, which caused shifts of -0.06 days over the entire western US, from -0.2 to 0.2 days across ecoregions, and -0.06 to 0.13 days across states. Overall, this study demonstrates that wildfires strongly impact SOS at local areas although the effect in the large region is relatively limited.

Options for an ignited tokamak

International Nuclear Information System (INIS)

Sheffield, J.

1984-02-01

It is expected that the next phase of the fusion program will involve a tokamak with the goals of providing an ignited plasma for pulses of hundreds of seconds. A simple model is described in this memorandum which establishes the physics conditions for such a self-sustaining plasma, for given ion and electron thermal diffusivities, in terms of R/a, b/a, I, B/q, epsilon β/sub p/, anti T/sub i/, and anti T/sub e//anti T/sub i/. The model is used to produce plots showing the wide range of tokamaks that may ignite or have a given ignition margin. The constraints that limit this range are discussed

Development of a simulation model for compression ignition engine running with ignition improved blend

Directory of Open Access Journals (Sweden)

Sudeshkumar Ponnusamy Moranahalli

2011-01-01

Full Text Available Department of Automobile Engineering, Anna University, Chennai, India. The present work describes the thermodynamic and heat transfer models used in a computer program which simulates the diesel fuel and ignition improver blend to predict the combustion and emission characteristics of a direct injection compression ignition engine fuelled with ignition improver blend using classical two zone approach. One zone consists of pure air called non burning zone and other zone consist of fuel and combustion products called burning zone. First law of thermodynamics and state equations are applied in each of the two zones to yield cylinder temperatures and cylinder pressure histories. Using the two zone combustion model the combustion parameters and the chemical equilibrium composition were determined. To validate the model an experimental investigation has been conducted on a single cylinder direct injection diesel engine fuelled with 12% by volume of 2- ethoxy ethanol blend with diesel fuel. Addition of ignition improver blend to diesel fuel decreases the exhaust smoke and increases the thermal efficiency for the power outputs. It was observed that there is a good agreement between simulated and experimental results and the proposed model requires low computational time for a complete run.

Plasma transport in a compact ignition tokamak

International Nuclear Information System (INIS)

Singer, C.E.; Ku, L.P; Bateman, G.

1987-02-01

Nominal predicted plasma conditions in a compact ignition tokamak are illustrated by transport simulations using experimentally calibrated plasma transport models. The range of uncertainty in these predictions is explored by using various models which have given almost equally good fits to experimental data. Using a transport model which best fits the data, thermonuclear ignition occurs in a Compact Ignition Tokamak design with major radius 1.32 m, plasma half-width 0.43 m, elongation 2.0, and toroidal field and plasma current ramped in six seconds from 1.7 to 10.4 T and 0.7 to 10 MA, respectively. Ignition is facilitated by 20 MW of heating deposited off the magnetic axis near the 3 He minority cyclotron resonance layer. Under these conditions, sawtooth oscillations are small and have little impact on ignition. Tritium inventory is minimized by preconditioning most discharges with deuterium. Tritium is injected, in large frozen pellets, only after minority resonance preheating. Variations of the transport model, impurity influx, heating profile, and pellet ablation rates, have a large effect on ignition and on the maximum beta that can be achieved

Ignition modes of nanosecond discharge with bubbles in distilled water

International Nuclear Information System (INIS)

Hamdan, Ahmad; Cha, Min Suk

2015-01-01

Here, we present the microscopic physical characteristics of nanosecond discharges with an array of bubbles in distilled water. In particular, applying a single high-voltage pulse, four delayed intensified charge-coupled device cameras successfully visualized four successive images during a single discharge event. We identified three distinctive modes of ignition inside a bubble, depending on the relative location of the bubble with respect to pin-to-hollow needle electrodes when a single bubble was located in an inter-electrode gap of 1 mm: anode-driven ignition, cathode-driven ignition, and co-ignition near both electrodes. Anode- and cathode-driven ignitions evolved into either a complete propagation of the streamer or an incomplete propagation, which were limited in location by proximity to an ignition location, while co-ignitions consistently showed complete propagation. When we increased the gap to 2 mm to accommodate multiple bubbles in the gap, an ignited bubble near the cathode was able to cause the ignition of an upper adjacent bubble. Bubble–bubble interface zones can also be spots of ignition, such that we observed simultaneous co-ignitions in the zones of bubble–bubble interfaces and near electrodes with triple bubbles. We compared the experimental results of discharge propagation with different ignition modes between Ar, He, and N 2 bubbles. In addition, numerical simulations for static electric fields reasonably supported observed ignition behavior such that field intensity was locally enhanced. (paper)

Kinetic mechanism of plasma-assisted ignition of hydrocarbons

International Nuclear Information System (INIS)

Kosarev, I N; Aleksandrov, N L; Kindysheva, S V; Starikovskaia, S M; Starikovskii, A Yu

2008-01-01

Ignition of hydrocarbon-containing gaseous mixtures has been studied experimentally and numerically under the action of a high-voltage nanosecond discharge at elevated temperatures. Ignition delay times were measured behind a reflected shock wave in stoichiometric C n H 2n+2 : O 2 mixtures (10%) diluted with Ar (90%) for n = 1-5. It was shown that the application of the gas discharge leads to more than an order of magnitude decrease in ignition delay time for all hydrocarbons under consideration. The measured values of ignition delay time agree well with the results of a numerical simulation of the ignition based on the calculation of atom and radical production during the discharge and in its afterglow. The analysis of simulation results showed that a non-equilibrium plasma favours the ignition mainly due to O atoms produced in the active phase of the discharge. (fast track communication)

Preparing for polar-drive ignition on the National Ignition Facility

Directory of Open Access Journals (Sweden)

McKenty P.W.

2013-11-01

Full Text Available The implementation of polar drive (PD at the National Ignition Facility (NIF will enable the execution of direct-drive implosions while the facility is configured for x-ray drive. The Laboratory for Laser Energetics (LLE, in collaboration with LLNL, LANL and GA, is implementing PD on the NIF. LLE has designed and participates in the use of PD implosions for diagnostic commissioning on the NIF. LLE has an active experimental campaign to develop PD in both warm and cryogenic target experiments on OMEGA. LLE and its partners are developing a Polar Drive Project Execution Plan, which will provide a detailed outline of the requirements, resources, and timetable leading to PD-ignition experiments on the NIF.

Levoglucosan Levels in Alaskan Ice Cores as a Record of Past Wildfires

Science.gov (United States)

Dunham, M. E.; Osterberg, E. C.; Kehrwald, N. M.; Kennedy, J.; Ferris, D. G.

2017-12-01

Glaciers in southeast Alaska are significant contributors to global sea-level rise, and therefore understanding the mechanisms driving their recent mass loss is crucial for predicting future sea-level change. Fire activity in Alaska has increased dramatically during the last decade, adding a potential new source of light-absorbing organic material (soot) to the Juneau Icefield that can reduce albedo and enhance surface melt rates. The goal of this project is to create an accurate record of Alaskan wildfires to understand how Alaskan glacial mass balance is affected by the deposition of organic aerosols from wildfires. Previously, oxalate, ammonia, and potassium ion levels have been used as proxies for past wildfire activity, but these ions all have broader emission sources in addition to wildfires. Here we develop a record of past Alaskan fire events and climate from: (1) levels of a biomass burning indicator, levoglucosan, which only forms when cellulose is burned over 300 °C, (2) major ions including oxalate, ammonia, and potassium; (3) the number and size distribution of particles to quantify trace amounts of soot from wildfires; and (4) stable water isotope ratios as a proxy for past temperature in ice cores. We utilize a total of four shallow ice cores, ranging from 7 to 9 m in length, that were collected by a biogeochemistry team during the Juneau Icefield Research Program (JIRP) in 2016. Complications include our limited understanding of the conservation and degradation of levoglucosan over time or during the firnification process. We hypothesize that particle counts will be correlated with levoglucosan peaks, co-varying with wildfire frequency and temperatures over time. Based on previous work, we also expect to find correlations between levoglucosan and oxalate ion concentrations, even though oxalate ions have sources in addition to wildfire activity.

Epidemic cholera spreads like wildfire

Science.gov (United States)

Roy, Manojit; Zinck, Richard D.; Bouma, Menno J.; Pascual, Mercedes

2014-01-01

Cholera is on the rise globally, especially epidemic cholera which is characterized by intermittent and unpredictable outbreaks that punctuate periods of regional disease fade-out. These epidemic dynamics remain however poorly understood. Here we examine records for epidemic cholera over both contemporary and historical timelines, from Africa (1990-2006) and former British India (1882-1939). We find that the frequency distribution of outbreak size is fat-tailed, scaling approximately as a power-law. This pattern which shows strong parallels with wildfires is incompatible with existing cholera models developed for endemic regions, as it implies a fundamental role for stochastic transmission and local depletion of susceptible hosts. Application of a recently developed forest-fire model indicates that epidemic cholera dynamics are located above a critical phase transition and propagate in similar ways to aggressive wildfires. These findings have implications for the effectiveness of control measures and the mechanisms that ultimately limit the size of outbreaks.

Amplification of wildfire area burnt by hydrological drought in the humid tropics

Science.gov (United States)

Taufik, Muh; Torfs, Paul J. J. F.; Uijlenhoet, Remko; Jones, Philip D.; Murdiyarso, Daniel; van Lanen, Henny A. J.

2017-06-01

Borneo's diverse ecosystems, which are typical humid tropical conditions, are deteriorating rapidly, as the area is experiencing recurrent large-scale wildfires, affecting atmospheric composition and influencing regional climate processes. Studies suggest that climate-driven drought regulates wildfires, but these overlook subsurface processes leading to hydrological drought, an important driver. Here, we show that models which include hydrological processes better predict area burnt than those solely based on climate data. We report that the Borneo landscape has experienced a substantial hydrological drying trend since the early twentieth century, leading to progressive tree mortality, more severe than in other tropical regions. This has caused massive wildfires in lowland Borneo during the past two decades, which we show are clustered in years with large areas of hydrological drought coinciding with strong El Niño events. Statistical modelling evidence shows amplifying wildfires and greater area burnt in response to El Niño/Southern Oscillation (ENSO) strength, when hydrology is considered. These results highlight the importance of considering hydrological drought for wildfire prediction, and we recommend that hydrology should be considered in future studies of the impact of projected ENSO strength, including effects on tropical ecosystems, and biodiversity conservation.

Fast-shock ignition: a new approach to inertial confinement fusion

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AH Farahbod

2013-03-01

Full Text Available  A new concept for inertial confinement fusion called fast-shock ignition (FSI is introduced as a credible scheme in order to obtain high target gain. In the proposed model, the separation of fuel ignition into two successive steps, under the suitable conditions, reduces required ignitor energy for the fuel ignition. The main procedure in FSI concept is compressing the fuel up to stagnation. Then, two high intensity short pulse laser spikes with energy and power lower than those required for shock ignition (SI and fast ignition (FI with a proper delay time are launched at the fuel which increases the central hot-spot temperature and completes the ignition of the precompressed fuel. The introduced semi-analytical model indicates that with fast-shock ignition, the total required energy for compressing and igniting the fuel can be slightly reduced in comparison to pure shock ignition. Furthermore, for fuel mass greater than , the target energy gain increases up to 15 percent and the contribution of fast ignitor under the proper conditions could be decreased about 20 percent compared with pure fast ignition. The FSI scheme is beneficial from technological considerations for the construction of short pulse high power laser drivers. The general advantages of fast-shock ignition over pure shock ignition in terms of figure of merit can be more than 1.3.

Advancing Sensor Technology to Monitor Wildfires

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EPA and partners are looking at ways to use miniature sensors to monitor air quality near wildfires. Data from these small sensors can complement measurements obtained from more complex regulatory-grade monitors that are stationary.

Investigating antennas as ignition aid for automotive HID lamps

International Nuclear Information System (INIS)

Bergner, A; Engelhardt, M; Bienholz, S; Ruhrmann, C; Hoebing, T; Groeger, S; Mentel, J; Awakowicz, P

2015-01-01

This paper considers the ignition of mercury-free high-intensity discharge (HID) lamps for car headlights. Due to safety reasons, these lamps need to have a fast run-up phase which is ensured, amongst other things, by a high Xe pressure of roughly 15 bar (cold) in the discharge vessel. The high Xe pressure causes an increased ignition voltage compared with former mercury-containing automotive HID lamps or low-pressure lamps used for general-lighting applications. The increase in ignition voltage can be limited if the electric field in front of the electrodes is raised by an uplifting of the electrical conductivity along the outer wall of the inner bulb either by a conductive layer on its surface or by a dielectric barrier discharge (DBD) within the outer bulb. This paper considers on the one hand conventional antennas deposited by physical vapour deposition (PVD) and on the other hand a combination of these antennas with a DBD within the outer-bulb operated in 100 mbar Ar as ignition aids. In both cases the antenna potential and antenna width are varied. Additionally, the effects of antenna thickness and antenna material are investigated. The ignition voltage, ignition current and light emission during ignition are measured on a nanosecond timescale. Furthermore, for the very first time, the ignition process is recorded in four consecutive intensified charge-coupled device images using a high-speed camera system with a time resolution in the range of nanoseconds. It was found that antennas strongly reduce the ignition voltage of automotive HID lamps. Active antennas reduce the ignition voltage significantly more than passive antennas, proportional to the conductance of the antenna. Combining conventional antennas with an outer-bulb discharge reduces the ignition voltage from 19 kV without any ignition aid to the intrinsic ignition voltage of the lamp below 10 kV, in the best case. (paper)

Ignition experiment in a single-turn-coil tokamak

International Nuclear Information System (INIS)

Carrera, R.; Driga, M.; Gully, J.H.

1989-01-01

A novel concept for a fusion ignition experiment, IGNITEX proposed along the lines of previous ideas for a compact thermonuclear device is analyzed. A single-turn-coil tokamak is analyzed. A single-turn-coil tokamak supplied by homopolar generators can ohmically heat a DT plasma to ignition conditions and maintain a thermally stable ignited phase for about ten energy confinement times. The IGNITEX experiment can provide a simple and relatively inexpensive way to produce and control ignited plasmas for scientific study

Ignition et oxydation des particules de combustible solide pulvérisé Ignition and Oxidation of Pulverized Solid Fuel

Directory of Open Access Journals (Sweden)

De Soete G. G.

2006-11-01

Full Text Available On présente dans cet article, en utilisant la méthode du ruban chauffé, une étude de la compétition entre (1 la dévolatilisation et l'oxydation consécutive des produits de pyrolyse et (2 l'ignition de la matrice solide et sa combustion rapide. La comparaison entre le moment de l'ignition et le début de la pyrolyse permet de déterminer en fonction de la température, de la taille des particules et de la concentration en oxygène, le domaine dans lequel l'ignition d'un combustible solide pyrolysable est du type whole coal ignition (c'est-à-dire lorsque l'ignition intervient avant que la pyrolyse devienne mesurable. Les résultats suggèrent que ce type d'ignition doit s'effectuer en règle générale dans les conditions de mise en oeuvre des combustibles solides pulvérisés dans les flammes industrielles. Dans le cas de l'ignition whole coal , la vitesse de combustion de la matrice solide est inhibée dans la période qui suit l'ignition. Cette inhibition est due d'une part à la difficulté pour l'oxygène de diffuser dans les pores pendant la sortie des produits de pyrolyse, et d'autre part à la consommation préférentielle de l'oxygène dans l'oxydation des produits de pyrolyse, principalement dans le cas où cette oxydation se développe sous forme de flamme. Ce n'est que lorsque la pyrolyse s'achève que la vitesse de combustion hétérogène peut atteindre sa valeur stationnaire normale, qui est alors pratiquement identique à celle du coke. Aux températures situées entre la température d'ignition du combustible solide et la température d'extinction du coke résiduel, la combustion est incomplète, une extinction intervenant à un degré de dévolatilisation d'autant plus grande que la température est élevée. Ce phénomène s'explique qualitativement par la théorie classique d'ignition thermique lorsqu'on l'applique au cas particulier des combustibles solides pyrolysables. Les températures d'ignition ainsi que les d