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At least 397 records · Page 22

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NASA NTRS2006

Ozone Production from the 2004 North American Boreal Fires

We examine the ozone production from boreal forest fires based on a case study of wildfires in Alaska and Canada in summer 2004. The model simulations were performed with the chemistry transport model, MOZART-4, and were evaluated by comparison with a comprehensive set of aircraft measurements. In the analysis we use measurements and model simulations of carbon monoxide (CO) and ozone (O3) at the PICO-NARE station located in the Azores within the pathway of North American outflow. The modeled mixing ratios were used to test the robustness of the enhancement ratio deltaO3/deltaCO (defined as the excess O3 mixing ratio normalized by the increase in CO) and the feasibility for using this ratio in estimating the O3 production from the wildfires. Modeled and observed enhancement ratios are about 0.25 ppbv/ppbv which is in the range of values found in the literature, and results in a global net O3 production of 12.9 2 Tg O3 during summer 2004. This matches the net O3 production calculated in the model for a region extending from Alaska to the East Atlantic (9-11 Tg O3) indicating that observations at PICO-NARE representing photochemically well-aged plumes provide a good measure of the O3 production of North American boreal fires. However, net chemical loss of fire related O3 dominates in regions far downwind from the fires (e.g. Europe and Asia) resulting in a global net O3 production of 6 Tg O3 during the same time period. On average, the fires increased the O3 burden (surface-300 mbar) over Alaska and Canada during summer 2004 by about 7-9%, and over Europe by about 2-3%.

Pfister, G. G.↗

NASA NTRS2008

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

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

Schneider, P.↗

NASA NTRS2005

Vehicle Assembly Building Fire Mishap Investigation Report. Volume I of V

On January 13, 2005, at approximately 1355, smoke was noticed on the 4th floor of D Tower in the Vehicle Assembly Building (VAB). Subsequently, a 911 call was made, a fire alarm pull station was activated, and the VAB was evacuated. The source of the smoke was determined to be a fire on the Low Bay M/N section roof near the Launch Control Center (LCC) Crossover. Due to the high visibility of the mishap, the KSC Center Director appointed a Mishap Investigation Board. Damage to government property was limited to the roof and a small number of ceiling tiles that were damaged by the fire fighters during the response. At the time of the mishap, there were hazardous commodities in the VAB including Solid Rocket Motors (SRMs) with open grain due to Solid Rocket Booster (SRB) igniter inspections. The Board agrees with the SGS Fire Services' theory that large amounts of smoke concentrated in the VAB D Tower and moved downward into the cable tunnel. The Board determined the proximate cause of this incident to be torching. HRI was installing a torch applied roof membrane which resulted in the ignition of combustible materials under the membrane near a wooden roof expansion joint. The torch applied roofing method is a universally accepted safe industry practice when applied to non-combustible surfaces. The combination of an open flame torch and combustible materiaLs presents an increased level of risk even with skilled applicators. The addition of high winds to this combination results in a risk the Board thinks can not be adequately mitigated. An appropriate risk assessment and analysis must be performed on the proposed roofing method to be used on high visibility facilities which represent unique national assets even when using common industry practices for repair and modification. The Board identified three root causes which contributed to or created the proximate cause and, if eliminated or modified, would have prevented the mishap: 1. Combustible materials in existing roof system 2. Wind speed and direction 3. Inadequate fire watch technique. Two contributing factors were identified which may have contributed to the occurrence but, if eliminated or modified, would not have prevented the occurrence: 1. HRI rushed to dry in and seal the roof on January 13 because heavy rain was predicted for the next day 2. No guidance on torching in windy conditions A total of 17 significant observations were noted during this investigation, which could lead to another mishap, or increase the severity of a mishap, but were not contributing factors in this mishap.

Kight, Ira↗

NASA NTRS2012

Radiative Forcing Due to Enhancements in Tropospheric Ozone and Carbonaceous Aerosols Caused by Asian Fires During Spring 2008

Simulations of tropospheric ozone and carbonaceous aerosol distributions, conducted with the Real-time Air Quality Modeling System (RAQMS), are used to study the effects of major outbreaks of fires that occurred in three regions of Asia, namely Thailand, Kazakhstan, and Siberia, during spring 2008. RAQMS is a global scale meteorological and chemical modeling system. Results from these simulations, averaged over April 2008, indicate that tropospheric ozone column increases by more than 10 Dobson units (DU) near the Thailand region, and by lesser amounts in the other regions due to the fires. Widespread increases in the optical depths of organic and black carbon aerosols are also noted. We have used an off-line radiative transfer model to evaluate the direct radiative forcing due to the fire-induced changes in atmospheric composition. For clear sky, the monthly averaged radiative forcing at the top of the atmosphere (TOA) is mostly negative with peak values less than -12 W/sq m occurring near the fire regions. The negative forcing represents the increased outgoing shortwave radiation caused by scattering due to carbonaceous aerosols. At high latitudes, the radiative forcing is positive due to the presence of absorbing aerosols over regions of high surface albedo. Regions of positive forcing at TOA are more pronounced under total sky conditions. The monthly averaged radiative forcing at the surface is mostly negative, and peak values of less than -30 W/sq m occur near the fire regions. Persistently large negative forcing at the surface could alter the surface energy budget and potentially weaken the hydrological cycle.

Natarajan, Murali↗

NASA NTRS2015

Hot-Fire Testing of a 1N AF-M315E Thruster

This hot-fire test continues NASA investigation of green propellant technologies for future missions. To show the potential for green propellants to replace some hydrazine systems in future spacecraft, NASA Marshall Space Flight Center (MSFC) is continuing to embark on hot-fire test campaigns with various green propellant blends. NASA completed a hot-fire test of a 1N AF-M315E monopropellant thruster at the Marshall Space Flight Center in the small altitude test stand located in building 4205. The thruster is a ground test article used for basic performance determination and catalyst studies. The purpose of the hot-fire testing was for performance determination of a 1N size thruster and form a baseline from which to study catalyst performance and life with follow-on testing to be conducted at a later date. The thruster performed as expected. The result of the hot-fire testing are presented in this paper and presentation.

Burnside, Christopher G.↗

NASA NTRS2016

Evaluation of Containment Boxes as a Fire Mitigation Method in Elevated Oxygen Conditions

NASA performed testing to evaluate the efficacy of fire containment boxes without forced ventilation. Configurational flammability testing was performed on a simulation avionics box replicating critical design features and filled with materials possessing representative flammability characteristics. This paper discusses the box's ability, under simulated end-use conditions, to inhibit the propagation of combustion to surrounding materials. Analysis was also performed to evaluate the potential for the fire containment box to serve as an overheat/ignition source to temperature sensitive equipment (such as items with lithium-ion batteries). Unrealistically severe combustion scenarios were used as a means to better understand the fire containment mechanism. These scenarios were achieved by utilizing materials/fuels not typically used in space vehicles due to flammability concerns. Oxygen depletion, during combustion within the fire containment boxes, drove self-extinguishment and proved an effective method of fire containment

Juarez, Alfredo↗

NASA NTRS2016

Use of a Small Unmanned Aircraft System for Autonomous Fire Spotting at the Great Dismal Swamp

This paper describes the results of a set of experiments and analyses conducted to evaluate the capability of small unmanned aircraft systems (sUAS) to spot nascent fires in the Great Dismal Swamp (GDS) National Wildlife Refuge. This work is the result of a partnership between the National Aeronautics and Space Administration and the US Fish and Wildlife service specifically to investigate sUAS usage for fire-spotting. The objectives of the current effort were to: 1) Determine suitability and utility of low-cost Small Unmanned Aircraft Systems (sUAS) to detect nascent fires at GDS; 2) Identify and assess the necessary National Airspace System (NAS) integration issues; and 3) Provide information to GDS and the community on system requirements and concepts-of-operation (CONOPS) for conducting fire detection/support mission in the National Airspace and (4) Identify potential applications of intelligent autonomy that would enable or benefit this high-value mission. In addition, data on the ability of various low-cost sensors to detect smoke plumes and fire hot spots was generated during the experiments as well as identifying a path towards a future practical mission utility by using sUAS in beyond visual-line-of-sight operation in the National Airspace System (NAS).

Logan, Michael J.↗

NASA NTRS2016

Fire Detection Tradeoffs as a Function of Vehicle Parameters

Fire survivability depends on the detection of and response to a fire before it has produced an unacceptable environment in the vehicle. This detection time is the result of interplay between the fire burning and growth rates; the vehicle size; the detection system design; the transport time to the detector (controlled by the level of mixing in the vehicle); and the rate at which the life support system filters the atmosphere, potentially removing the detected species or particles. Given the large differences in critical vehicle parameters (volume, mixing rate and filtration rate) the detection approach that works for a large vehicle (e.g. the ISS) may not be the best choice for a smaller crew capsule. This paper examines the impact of vehicle size and environmental control and life support system parameters on the detectability of fires in comparison to the hazard they present. A lumped element model was developed that considers smoke, heat, and toxic product release rates in comparison to mixing and filtration rates in the vehicle. Recent work has quantified the production rate of smoke and several hazardous species from overheated spacecraft polymers. These results are used as the input data set in the lumped element model in combination with the transport behavior of major toxic products released by overheating spacecraft materials to evaluate the necessary alarm thresholds to enable appropriate response to the fire hazard.

microgravity↗

NASA NTRS2016

Fire Detection Tradeoffs as a Function of Vehicle Parameters

microgravity↗

NASA NTRS2016

Agricultural Fires in the Southeastern U.S. During SEAC4RS: Emissions of Trace Gases and Particles and Evolution of Ozone, Reactive Nitrogen, and Organic Aerosol

Emissions from 15 agricultural fires in the southeastern U.S. were measured from the NASA DC-8 research aircraft during the summer 2013 Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) campaign. This study reports a detailed set of emission factors (EFs) for 25 trace gases and 6 fine particle species. The chemical evolution of the primary emissions in seven plumes was examined in detail for ~1.2 h. A Lagrangian plume cross-section model was used to simulate the evolution of ozone (O3), reactive nitrogen species, and organic aerosol (OA). Observed EFs are generally consistent with previous measurements of crop residue burning, but the fires studied here emitted high amounts of SO2 and fine particles, especially primary OA and chloride. Filter-based measurements of aerosol light absorption implied that brown carbon (BrC) was ubiquitous in the plumes. In aged plumes, rapid production of O3, peroxyacetyl nitrate (PAN), and nitrate was observed with (Delta)O3/(Delta)CO, (Delta)PAN/(Delta)NOy, and (Delta)nitrate/(Delta)NOy reaching approx. 0.1, approx. 0.3, and approx.0.3. For five selected cases, the model reasonably simulated O3 formation but underestimated PAN formation. No significant evolution of OA mass or BrC absorption was observed. However, a consistent increase in oxygen-to-carbon (O/C) ratios of OA indicated that OA oxidation in the agricultural fire plumes was much faster than in urban and forest fire plumes. Finally, total annual SO2, NOx, and CO emissions from agricultural fires in Arkansas, Louisiana, Mississippi, and Missouri were estimated (within a factor of approx. 2) to be equivalent to approx. 2% SO2 from coal combustion and approx. 1% NOx and approx. 9% CO from mobile sources.

OA mass or BrC absorption↗

NASA NTRS2017

Quantifying Black Carbon Deposition Over the Greenland Ice Sheet from Forest Fires in Canada

Black carbon (BC) concentrations observed in 22 snowpits sampled in the northwest sector of the Greenland ice sheet in April 2014 have allowed us to identify a strong and widespread BC aerosol deposition event, which was dated to have accumulated in the pits from two snow storms between 27 July and 2 August 2013. This event comprises a significant portion (57 on average across all pits) of total BC deposition over 10 months (July 2013 to April 2014). Here we link this deposition event to forest fires burning in Canada during summer 2013 using modeling and remote sensing tools. Aerosols were detected by both the Cloud-Aerosol Lidar with Orthogonal Polarization (on board CALIPSO) and Moderate Resolution Imaging Spectroradiometer (Aqua) instruments during transport between Canada and Greenland. We use high-resolution regional chemical transport modeling (WRF-Chem) combined with high-resolution fire emissions (FINNv1.5) to study aerosol emissions, transport, and deposition during this event. The model captures the timing of the BC deposition event and shows that fires in Canada were the main source of deposited BC. However, the model underpredicts BC deposition compared to measurements at all sites by a factor of 2100. Underprediction of modeled BC deposition originates from uncertainties in fire emissions and model treatment of wet removal of aerosols. Improvements in model descriptions of precipitation scavenging and emissions from wildfires are needed to correctly predict deposition, which is critical for determining the climate impacts of aerosols that originate from fires.

albedo↗

NASA NTRS2017

Saffire: A Novel Approach to Study of Spacecraft Fire Safety Using Un-Manned Spacecraft

The Saffire Experiment represents the first test of spacecraft fires at a scale relevant to real spacecraft. Although large-scale fire tests on Earth are conducted for every type of habitable structure (buildings, planes, trains, automobiles, ships and mines) they had never been attempted in a space experiment for obvious reasons of practicality and safety. This is despite the fact that fire is a catastrophic hazard for spaceflight where the crew has very limited or no escape options. The spread and growth of a fire, combined with its interactions with the vehicle cannot be expected to scale linearly from small-scale test data, and so there is a substantial gap in our ability to predict the behavior of spacecraft fire and also its impact on the spacecraft habitability and operability. The experiments were performed aboard the Cygnus vehicle, a large unmanned resupply spacecraft to the International Space Station (ISS). The experiment was installed in the Cygnus vehicle, and remained dormant during docked operations. Once the vehicle was reloaded with ISS trash, it unberthed and moved to a separate orbit. The Saffire experiment was initiated by ground command and downlinked the data before the vehicle re-entered into the earth's atmosphere. The downloaded test data show resolved the question of whether flame growth will achieve a steady size and demonstrated that the size of the enclosure surrounding the sample has more impact on the flame spread than anticipated.

microgravity↗

NASA NTRSDate not supplied

NASA Update: Wildland Fire Element

As the NASA ESD, Applied Science Program, Associate Program Manager responsible for the agency's Wildland Fire Program portfolio, Vince Ambrosia manages and oversees NASA's participation in developments of Earth Observations capabilities supporting improved wildland fire management. The Wildland Fire Program has been subsumed within the ASP Disaster Program element and focuses on the NASA progress developments of the Group on Earth Observations (GEO) Global Wildfire Information System, where V. Ambrosia also serves as the GEO-GWIS NASA representative to the international panel. The NASA GWIS developments for the past year are highlighted in the briefing. In addition, other wildland fire-related NASA projects are also highlighted in this presentation, providing a context for the various successful developments and operationalization of Earth Observing systems data by partner entities and organizations involved in fire management.

Vince Ambrosia↗

NASA NTRSDate not supplied

In Situ Measurements of Ammonia In Plumes Emitted From Wildfires And Agricultural Fires in the US

Emissions of trace gases and particles from fires have a major impact on climate, visibility, air quality, and public health. Biomass burning emissions include reactive nitrogen gases, among which ammonia (NH3) plays a prominent role. NH3 is a short-lived gas that acts as precursor for secondary inorganic aerosols. This process is still poorly constrained in downwind fire plumes. In summer 2019, NASA and NOAA carried out the joint airborne FIREX-AQ (Fire Influence on Regional to global Environments and Air Quality) mission over the continental US to sample plumes from wildfires and agricultural fires. On board the NASA DC-8, we used a modified PTR-ToF-MS instrument for measuring NH3 in situ and at high time resolution. Over the course of the mission, we collected a large set of NH3 data in plumes emitted from fires differing in fuel type and burning stage. Herein, we will present the measured NH3 emissions ratios and factors, compare them with the literature, and investigate the dependence of NH3 emissions on fuel type and burning conditions.

ammonia↗

NASA NTRS2018

Predicting Rapid Fire Growth (Flashover) Using Generative Adversarial Networks

A flashover occurs when a fire spreads very rapidly through crevices due to intense heat. Flashovers present one of the most frightening and challenging fire phenomena to those who regularly encounter them: firefighters. Firefighters’ safety and lives often depend on their ability to predict flashovers before they occur. Typical pre-flashover fire characteristics include dark smoke, high heat, and rollover (“angel fingers”) and can be quantified by color, size, and shape. Using a color video stream from a firefighter’s body camera, we applied generative adversarial neural networks for image enhancement. The neural networks were trained to enhance very dark fire and smoke patterns in videos and monitor dynamic changes in smoke and fire areas. Preliminary tests with limited flashover training videos showed that we predicted a flashover as early as 55 seconds before it occurred.

Lu, Thomas↗

NASA NTRS2021

Research Questions and Challenges for Improved Spacecraft Fire Detection

This paper describes challenges and recommendations for research to improve spacecraft fire detection. Because crew safety is critical to every spaceflight mission, effective fire detectors must detect a wide variety of fires to ensure the success of future space exploration. Fire emissions are affected by fuel type, heating conditions, gravity and exploration atmosphere. Advances in sensing technology provide a promising basis for future detectors, which must selectively detect a broad variety of fires. Addressing these areas will secure the success of future lunar and deep space missions.

Claire Fortenberry↗

NASA NTRSDate not supplied

Mapping Forest Carbon Stocks to Understand Carbon Implications of Treatment on Wildfire for the Calwood Fire, Boulder County Colorado

Recent, record-breaking wildfire activity in the western U.S. illustrates the need for fire mitigation, such as forest fuels reduction treatments. Forests serve as crucial carbon sinks that combat the increasing effects of climate change, but fuels reduction treatments may remove carbon from forested systems. As a result, forest managers need to find a balance between fire mitigation and carbon preservation. This project partnered with Boulder County Parks and Open Space (BCPOS) and the University of Colorado, Denver to investigate the 2020 Cal-Wood fire in Boulder County, Colorado. Using remote sensing data from Landsat 8 Operational Land Imager, Shuttle Radar Topography Mission, Sentinel-2 MultiSpectral Imagery, and LiDAR, we mapped post-fire forest carbon pools and compared these values with values derived from field measurements. The analysis suggested that fuels reduction treatments did not reduce carbon loss in the presence of wildfire enough to clearly distinguish post-fire carbon between treated and untreated areas. However, the final carbon maps provide BCPOS and researchers with an opportunity to explore carbon estimation models based on remote sensing data as well as a framework to evaluate fuels reduction treatment effectiveness and impact on forest carbon stocks for future wildfire events.

Sarah Hettema↗

DOE OSTI2025

Modeling the impact of smoke from prescribed fire on road visibility

Prescribed fires are planned to achieve conservation and fuel reduction objectives while minimizing smoke ground concentration to limit health impacts and road visibility impairment. Prescribed burns cannot indeed be conducted if those hazards are not within predefined limits. This paper proposes a new framework to evaluate road visibility that overcomes the limitation of the state of the art model, VSMOKE. The framework leverages the fast-running framework QUIC-Fire/QUIC-SMOKE to capture fire and smoke dynamics, and the timing and duration of hazardous conditions on the road network close to the burn unit (within 50–100 km). The paper presents parametric study using a real burn plot at Fort Stewart (GA, USA), under hypothetical wind conditions to understand the interplay between buoyancy and smoke dilution. Here, results showed that faster winds caused fire escape while slower winds did not achieve a complete burn. Furthermore, faster winds featured brief road visibility reduction below braking distance.

54 ENVIRONMENTAL SCIENCES↗