Science.gov

Sample records for active fire observations

  1. Patterns of fire activity over Indonesia and Malaysia from polar and geostationary satellite observations

    NASA Astrophysics Data System (ADS)

    Hyer, Edward J.; Reid, Jeffrey S.; Prins, Elaine M.; Hoffman, Jay P.; Schmidt, Christopher C.; Miettinen, Jukka I.; Giglio, Louis

    2013-03-01

    Biomass burning patterns over the Maritime Continent of Southeast Asia are examined using a new active fire detection product based on application of the Wildfire Automated Biomass Burning Algorithm (WF_ABBA) to data from the imagers on the MTSAT geostationary satellites operated by the Japanese space agency JAXA. Data from MTSAT-1R and MTSAT-2 covering 34 months from September 2008 to July 2011 are examined for a study region consisting of Indonesia, Malaysia, and nearby environs. The spatial and temporal distributions of fires detected in the MTSAT WF_ABBA product are described and compared with active fire observations from MODIS MOD14 data. Land cover distributions for the two instruments are examined using a new 250 m land cover product from the National University of Singapore. The two products show broadly similar patterns of fire activity, land cover distribution of fires, and pixel fire radiative power (FRP). However, the MTSAT WF_ABBA data differ from MOD14 in important ways. Relative to MODIS, the MTSAT WF_ABBA product has lower overall detection efficiency, but more fires detected due to more frequent looks, a greater relative fraction of fires in forest and a lower relative fraction of fires in open areas, and significantly higher single-pixel retrieved FRP. The differences in land cover distribution and FRP between the MTSAT and MODIS products are shown to be qualitatively consistent with expectations based on pixel size and diurnal sampling. The MTSAT WF_ABBA data are used to calculate coverage-corrected diurnal cycles of fire for different regions within the study area. These diurnal cycles are preliminary but demonstrate that the fraction of diurnal fire activity sampled by the two MODIS sensors varies significantly by region and vegetation type. Based on the results from comparison of the two fire products, a series of steps is outlined to account for some of the systematic biases in each of these satellite products in order to produce a

  2. Multisensor Fire Observations

    NASA Technical Reports Server (NTRS)

    Boquist, C.

    2004-01-01

    This DVD includes animations of multisensor fire observations from the following satellite sources: Landsat, GOES, TOMS, Terra, QuikSCAT, and TRMM. Some of the animations are included in multiple versions of a short video presentation on the DVD which focuses on the Hayman, Rodeo-Chediski, and Biscuit fires during the 2002 North American fire season. In one version of the presentation, MODIS, TRMM, GOES, and QuikSCAT data are incorporated into the animations of these wildfires. These data products provided rain, wind, cloud, and aerosol data on the fires, and monitored the smoke and destruction created by them. Another presentation on the DVD consists of a panel discussion, in which experts from academia, NASA, and the U.S. Forest Service answer questions on the role of NASA in fighting forest fires, the role of the Terra satellite and its instruments, including the Moderate Resolution Imaging Spectroradiometer (MODIS), in fire fighting decision making, and the role of fire in the Earth's climate. The third section of the DVD features several animations of fires over the years 2001-2003, including animations of global and North American fires, and specific fires from 2003 in California, Washington, Montana, and Arizona.

  3. Active Fire Mapping Program

    MedlinePlus

    Active Fire Mapping Program Current Large Incidents (Home) New Large Incidents Fire Detection Maps MODIS Satellite Imagery VIIRS Satellite Imagery Fire Detection GIS Data Fire Data in Google Earth ...

  4. Combining Satellite Observations of Fire Activity and Numerical Weather Prediction to Improve the Prediction of Smoke Emissions

    NASA Astrophysics Data System (ADS)

    Peterson, D. A.; Wang, J.; Hyer, E. J.; Ichoku, C. M.

    2012-12-01

    Smoke emissions estimates used in air quality and visibility forecasting applications are currently limited by the information content of satellite fire observations, and the lack of a skillful short-term forecast of changes in fire activity. This study explores the potential benefits of a recently developed sub-pixel-based calculation of fire radiative power (FRPf) from the MODerate Resolution Imaging Spectroradiometer (MODIS), which provides more precise estimates of the radiant energy (over the retrieved fire area) that in turn, improves estimates of the thermal buoyancy of smoke plumes and may be helpful characterizing the meteorological effects on fire activity for large fire events. Results show that unlike the current FRP product, the incorporation of FRPf produces a statistically significant correlation (R = 0.42) with smoke plume height data provided by the Multi-angle Imaging SpectroRadiometer (MISR) and several meteorological variables, such as surface wind speed and temperature, which may be useful for discerning cases where smoke was injected above the boundary layer. Drawing from recent advances in numerical weather prediction (NWP), this study also examines the meteorological conditions characteristic of fire ignition, growth, decay, and extinction, which are used to develop an automated, 24-hour prediction of satellite fire activity. Satellite fire observations from MODIS and geostationary sensors show that the fire prediction model is an improvement (RMSE reduction of 13 - 20%) over the forecast of persistence commonly used by near-real-time fire emission inventories. The ultimate goal is to combine NWP data and satellite fire observations to improve both analysis and prediction of biomass-burning emissions, through improved understanding of the interactions between fire activity and weather at scales appropriate for operational modeling. This is a critical step toward producing a global fire prediction model and improving operational forecasts of

  5. South America Fire Observations

    NASA Video Gallery

    From space, we can understand fires in ways that are impossible from the ground. NASA research has contributed to much improved detection of fire for scientific purposes using satellite remote sens...

  6. FIRE I - Extended Time Observations Data Sets

    Atmospheric Science Data Center

    2013-08-01

    FIRE I - Extended Time Observations Data Sets First ISCCP Regional Experiment (FIRE) I - Extended Time Observations were conducted in Utah. Relevant Documents:  FIRE Project Guide FIRE I - Extended Time Observations Home Page SCAR-B Block:  ...

  7. Evaluating greenhouse gas emissions inventories for agricultural burning using satellite observations of active fires.

    PubMed

    Lin, Hsiao-Wen; Jin, Yufang; Giglio, Louis; Foley, Jonathan A; Randerson, James T

    2012-06-01

    Fires in agricultural ecosystems emit greenhouse gases and aerosols that influence climate on multiple spatial and temporal scales. Annex 1 countries of the United Nations Framework Convention on Climate Change (UNFCCC), many of which ratified the Kyoto Protocol, are required to report emissions of CH4 and N2O from these fires annually. In this study, we evaluated several aspects of this reporting system, including the optimality of the crops targeted by the UNFCCC globally and within Annex 1 countries, and the consistency of emissions inventories among different countries. We also evaluated the success of individual countries in capturing interannual variability and long-term trends in agricultural fire activity. In our approach, we combined global high-resolution maps of crop harvest area and production, derived from satellite maps and ground-based census data, with Terra and Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) measurements of active fires. At a global scale, we found that adding ground nuts (e.g., peanuts), cocoa, cotton and oil palm, and removing potato, oats, rye, and pulse other from the list of 14 crops targeted by the UNFCCC increased the percentage of active fires covered by the reporting system by 9%. Optimization led to a different recommended list for Annex 1 countries, requiring the addition of sunflower, cotton, rapeseed, and alfalfa and the removal of beans, sugarcane, pulse others, and tuber-root others. Extending emissions reporting to all Annex 1 countries (from the current set of 19 countries) would increase the efficacy of the reporting system from 6% to 15%, and further including several non-Annex 1 countries (Argentina, Brazil, China, India, Indonesia, Thailand, Kazakhstan, Mexico, and Nigeria) would capture over 55% of active fires in croplands worldwide. Analyses of interannual trends from the United States and Australia showed the importance of both intensity of fire use and crop production in controlling year

  8. A short-term predictor of satellite-observed fire activity in the North American boreal forest: Toward improving the prediction of smoke emissions

    NASA Astrophysics Data System (ADS)

    Peterson, David; Hyer, Edward; Wang, Jun

    2013-06-01

    A statistical model, based on numerical weather prediction (NWP), is developed to predict the subsequent day's satellite observations of fire activity in the North American boreal forest during the fire season (24-h forecast). In conjunction with the six components of the Canadian Forest Fire Danger Rating System and other NWP outputs, fire data from the MODerate Resolution Imaging Spectroradiometer (MODIS) and the Geostationary Operational Environmental Satellites (GOES) are used to examine the meteorological separability between the largest fire growth and decay events, with a focus on central Alaska during the large fire season of 2004. This combined information is analyzed in three steps including a maximum likelihood classification, multiple regression, and empirical correction, from which the meteorological effects on fire growth and decay are statistically established to construct the fire prediction model. Both MODIS and GOES fire observations show that the NWP-based fire prediction model is an improvement over the forecast of persistence commonly used by near-real-time fire emission inventories. Results from an independent test (2005 fire season) show that the root-mean-square error (RMSE) of predicted MODIS fire observations is reduced by 5.2% compared with a persistence forecast. Improvements are strongest (RMSE reduction of 11.4%) for cases with observed decay or extinction of fires. Similar results are obtained from additional independent tests using the 2004 and 2005 GOES satellite fire observations. This study uniquely demonstrates the value and importance of combining NWP data and satellite fire observations to predict biomass-burning emissions, which is a critical step toward producing a global short-term fire prediction model and improving operational forecasts of smoke transport at large spatial scales.

  9. Remote optical observations of actively burning biomass fires using potassium line spectral emission

    NASA Astrophysics Data System (ADS)

    Magidimisha, Edwin; Griffith, Derek J.

    2016-02-01

    Wildland fires are a widespread, seasonal and largely man-made hazard which have a broad range of negative effects. These wildfires cause not only the destruction of homes, infrastructure, cultivated forests and natural habitats but also contribute to climate change through greenhouse gas emissions and aerosol particle production. Global satellite-based monitoring of biomass burning using thermal infrared sensors is currently a powerful tool to assist in finding ways to establish suppression strategies and to understand the role that fires play in global climate change. Advances in silicon-based camera technology present opportunities to resolve the challenge of ubiquitous wildfire early detection in a cost-effective manner. This study investigated several feasibility aspects of detecting wildland fires using near-infrared (NIR) spectral line emissions from electronically excited potassium (K) atoms at wavelengths of 766.5 and 769.9 nm, during biomass burning.

  10. Controls on fire activity over the Holocene

    NASA Astrophysics Data System (ADS)

    Kloster, S.; Brücher, T.; Brovkin, V.; Wilkenskjeld, S.

    2014-11-01

    Changes in fire activity over the last 8000 years are simulated with a global fire model driven by changes in climate and vegetation cover. The changes were separated into those caused through variations in fuel availability, fuel moisture or wind speed which react differently to changes in climate. Disentangling these controlling factors helps to understand the overall climate control on fire activity over the Holocene. Globally the burned area is simulated to increase by 2.5% between 8000 and 200 cal yr BP with larger regional changes compensating on a global scale. Despite the absence of anthropogenic fire ignitions, the simulated trends in fire activity agree reasonably well with continental scale reconstructions from charcoal records, with the exception of Europe. For some regions the change in fire activity is predominantly controlled through changes in fuel availability (Australia-Monsoon, American Tropics/Subtropics). For other regions changes in fuel moisture are more important for the overall trend in fire activity (North America, Sub-Saharan Africa, Europe, Asia-Monsoon). In Sub-Saharan Africa, for example, changes in fuel moisture alone lead to an increase in fire activity between 8000 and 200 cal yr BP, while changes in fuel availability lead to a decrease. Overall, the fuel moisture control is dominating the simulated fire activity for Sub-Saharan Africa. The simulations clearly demonstrate that both changes in fuel availability and changes in fuel moisture are important drivers for the fire activity over the Holocene. Fuel availability and fuel moisture do, however, have different climate controls. As such observed changes in fire activity can not be related to single climate parameters such as precipitation or temperature alone. Fire models, as applied in this study, in combination with observational records can help to understand the climate control on fire activity, which is essential to project future fire activity.

  11. Controls on fire activity over the Holocene

    NASA Astrophysics Data System (ADS)

    Kloster, S.; Brucher, T.; Brovkin, V.; Wilkenskjeld, S.

    2015-05-01

    Changes in fire activity over the last 8000 years are simulated with a global fire model driven by changes in climate and vegetation cover. The changes were separated into those caused through variations in fuel availability, fuel moisture or wind speed, which react differently to changes in climate. Disentangling these controlling factors helps in understanding the overall climate control on fire activity over the Holocene. Globally the burned area is simulated to increase by 2.5% between 8000 and 200 cal yr BP, with larger regional changes compensating nearly evening out on a global scale. Despite the absence of anthropogenic fire ignitions, the simulated trends in fire activity agree reasonably well with continental-scale reconstructions from charcoal records, with the exception of Europe. For some regions the change in fire activity is predominantly controlled through changes in fuel availability (Australia monsoon, Central America tropics/subtropics). For other regions changes in fuel moisture are more important for the overall trend in fire activity (North America, Sub-Saharan Africa, Europe, Asia monsoon). In Sub-Saharan Africa, for example, changes in fuel moisture alone lead to an increase in fire activity between 8000 and 200 cal yr BP, while changes in fuel availability lead to a decrease. Overall, the fuel moisture control is dominating the simulated fire activity for Sub-Saharan Africa. The simulations clearly demonstrate that both changes in fuel availability and changes in fuel moisture are important drivers for the fire activity over the Holocene. Fuel availability and fuel moisture do, however, have different climate controls. As such, observed changes in fire activity cannot be related to single climate parameters such as precipitation or temperature alone. Fire models, as applied in this study, in combination with observational records can help in understanding the climate control on fire activity, which is essential to project future fire

  12. New fire diurnal cycle characterizations to improve fire radiative energy assessments made from MODIS observations

    NASA Astrophysics Data System (ADS)

    Andela, N.; Kaiser, J. W.; van der Werf, G. R.; Wooster, M. J.

    2015-08-01

    Accurate near real time fire emissions estimates are required for air quality forecasts. To date, most approaches are based on satellite-derived estimates of fire radiative power (FRP), which can be converted to fire radiative energy (FRE) which is directly related to fire emissions. Uncertainties in these FRE estimates are often substantial. This is for a large part because the most often used low-Earth orbit satellite-based instruments such as the Moderate Resolution Imaging Spectroradiometer (MODIS) have a relatively poor sampling of the usually pronounced fire diurnal cycle. In this paper we explore the spatial variation of this fire diurnal cycle and its drivers using data from the geostationary Meteosat Spinning Enhanced Visible and Infrared Imager (SEVIRI). In addition, we sampled data from the SEVIRI instrument at MODIS detection opportunities to develop two approaches to estimate hourly FRE based on MODIS active fire detections. The first approach ignored the fire diurnal cycle, assuming persistent fire activity between two MODIS observations, while the second approach combined knowledge on the climatology of the fire diurnal cycle with active fire detections to estimate hourly FRE. The full SEVIRI time series, providing full coverage of the fire diurnal cycle, were used to evaluate the results. Our study period comprised of 3 years (2010-2012), and we focused on Africa and the Mediterranean basin to avoid the use of potentially lower quality SEVIRI data obtained at very far off-nadir view angles. We found that the fire diurnal cycle varies substantially over the study region, and depends on both fuel and weather conditions. For example, more "intense" fires characterized by a fire diurnal cycle with high peak fire activity, long duration over the day, and with nighttime fire activity are most common in areas of large fire size (i.e., large burned area per fire event). These areas are most prevalent in relatively arid regions. Ignoring the fire diurnal

  13. Suomi NPP VIIRS active fire product status

    NASA Astrophysics Data System (ADS)

    Ellicott, E. A.; Csiszar, I. A.; Schroeder, W.; Giglio, L.; Wind, B.; Justice, C. O.

    2012-12-01

    We provide an overview of the evaluation and development of the Active Fires product derived from the Visible Infrared Imager Radiometer Suite (VIIRS) sensor on the Suomi National Polar-orbiting Partnership (SNPP) satellite during the first year of on-orbit data. Results from the initial evaluation of the standard SNPP Active Fires product, generated by the SNPP Interface Data Processing System (IDPS), supported the stabilization of the VIIRS Sensor Data Record (SDR) product. This activity focused in particular on the processing of the dual-gain 4 micron VIIRS M13 radiometric measurements into 750m aggregated data, which are fundamental for active fire detection. Following the VIIRS SDR product's Beta maturity status in April 2012, correlative analysis between VIIRS and near-simultaneous fire detections from the Moderate Resolution Imaging Spectroradiometer (MODIS) on the NASA Earth Observing System Aqua satellite confirmed the expected relative detection rates driven primarily by sensor differences. The VIIRS Active Fires Product Development and Validation Team also developed a science code that is based on the latest MODIS Collection 6 algorithm and provides a full spatially explicit fire mask to replace the sparse array output of fire locations from a MODIS Collection 4 equivalent algorithm in the current IDPS product. The Algorithm Development Library (ADL) was used to support the planning for the transition of the science code into IDPS operations in the future. Product evaluation and user outreach was facilitated by a product website that provided end user access to fire data in user-friendly format over North America as well as examples of VIIRS-MODIS comparisons. The VIIRS fire team also developed an experimental product based on 375m VIIRS Imagery band measurements and provided high quality imagery of major fire events in US. By August 2012 the IDPS product achieved Beta maturity, with some known and documented shortfalls related to the processing of

  14. Investigation of Biomass Combustion Rate of Fire Radiative Energy Using Multiple-Satellite-observed Active Fires and Landsat TM Burn Severities across the Continental United States

    NASA Astrophysics Data System (ADS)

    Li, F.; Zhang, X.; Kondragunta, S.

    2015-12-01

    Biomass burning is a major source of atmospheric aerosol and greenhouse gases that substantially influence climate and regional air quality. However, the accuracy of biomass burning emissions estimated using traditional method is limited by large uncertainties in burned area and fuel loading. Alternatively, fire radiative energy (FRE) has recently been demonstrated to be linearly related to biomass combustion, which potentially improves the estimation of biomass burning emissions. The FRE-based combustion rate is 0.368-0.453 kg/MJ according to field controlled experiments while it varies from 1.37-4.5 kg/MJ derived from satellite-based bottom-up and top-down aerosol optical thickness estimates. Here we investigate the FRE combustion rate in over 1000 burn scars from 2011 to 2012 across the Continental United States (CONUS). Specifically, FRE was calculated by combining the high spatial observations from the Moderate Resolution Imaging Spectroradiometer (MODIS) and the high temporal observations from the Geostationary Operational Environmental Satellite (GOES). Biomass consumption in burn scars was modeled using Landsat TM 30m burn severities, 30m fuel loading from Fuel Characteristic Classification System, and combustion completeness compiled from recent literatures. The combustion rate was then investigated by correlating FRE to biomass consumption across CONUS and Bailey's ecoregions. Our results show that the combustion rate can be extracted from the linear relationship between biomass consumption and FRE. The combustion rate is 0.415±10% kg/MJ across CONUS, which is similar to the rate derived from field experiments. However, it varies from 0.18-1.9 kg/MJ among ecoregions. This implies that a single combustion rate could produce large uncertainty in the estimation of biomass consumption at large scales. We suggest that ecoregion specified combustion rates should help to improve the accuracy of quantifying biomass burning emissions regionally and globally.

  15. Projecting climate-driven increases in North American fire activity

    NASA Astrophysics Data System (ADS)

    Wang, D.; Morton, D. C.; Collatz, G. J.

    2013-12-01

    Climate regulates fire activity through controls on vegetation productivity (fuels), lightning ignitions, and conditions governing fire spread. In many regions of the world, human management also influences the timing, duration, and extent of fire activity. These coupled interactions between human and natural systems make fire a complex component of the Earth system. Satellite data provide valuable information on the spatial and temporal dynamics of recent fire activity, as active fires, burned area, and land cover information can be combined to separate wildfires from intentional burning for agriculture and forestry. Here, we combined satellite-derived burned area data with land cover and climate data to assess fire-climate relationships in North America between 2000-2012. We used the latest versions of the Global Fire Emissions Database (GFED) burned area product and Modern-Era Retrospective Analysis for Research and Applications (MERRA) climate data to develop regional relationships between burned area and potential evaporation (PE), an integrated dryness metric. Logistic regression models were developed to link burned area with PE and individual climate variables during and preceding the fire season, and optimal models were selected based on Akaike Information Criterion (AIC). Overall, our model explained 85% of the variance in burned area since 2000 across North America. Fire-climate relationships from the era of satellite observations provide a blueprint for potential changes in fire activity under scenarios of climate change. We used that blueprint to evaluate potential changes in fire activity over the next 50 years based on twenty models from the Coupled Model Intercomparison Project Phase 5 (CMIP5). All models suggest an increase of PE under low and high emissions scenarios (Representative Concentration Pathways (RCP) 4.5 and 8.5, respectively), with largest increases in projected burned area across the western US and central Canada. Overall, near

  16. Biomass burning emissions estimated with a global fire assimilation system based on observed fire radiative power

    NASA Astrophysics Data System (ADS)

    Kaiser, J. W.; Heil, A.; Andreae, M. O.; Benedetti, A.; Chubarova, N.; Jones, L.; Morcrette, J.-J.; Razinger, M.; Schultz, M. G.; Suttie, M.; van der Werf, G. R.

    2011-07-01

    The Global Fire Assimilation System (GFASv1.0) calculates biomass burning emissions by assimilating Fire Radiative Power (FRP) observations from the MODIS instruments onboard the Terra and Aqua satellites. It corrects for gaps in the observations, which are mostly due to cloud cover, and filters spurious FRP observations of volcanoes, gas flares and other industrial activity. The combustion rate is subsequently calculated with land cover-specific conversion factors. Emission factors for 40 gas-phase and aerosol trace species have been compiled from a literature survey. The corresponding daily emissions have been calculated on a global 0.5° × 0.5° grid from 2003 to the present. General consistency with the Global Fire Emission Database version 3.1 (GFED3.1) within its accuracy is achieved while maintaining the advantages of an FRP-based approach: GFASv1.0 makes use of the quantitative information on the combustion rate that is contained in the observations, and it detects fires in real time at high spatial and temporal resolution. GFASv1.0 indicates omission errors in GFED3.1 due to undetected small fires. It also exhibits slightly longer fire seasons in South America and North Africa and a slightly shorter fire season in Southeast Asia. GFASv1.0 has already been used for atmospheric reactive gas simulations in an independent study, which found good agreement with atmospheric observations. We have performed simulations of the atmospheric aerosol distribution with and without the assimilation of MODIS aerosol optical depth (AOD). They indicate that the emissions of particulate matter need to be boosted with a factor of 2-4 to reproduce the global distribution of organic matter and black carbon. This discrepancy is also evident in the comparison of previously published top-down and bottom-up estimates. For the time being, a global enhancement of the particulate matter emissions by 3.4 is recommended. Validation with independent AOD and PM10 observations recorded

  17. Biomass burning emissions estimated with a global fire assimilation system based on observed fire radiative power

    NASA Astrophysics Data System (ADS)

    Kaiser, J. W.; Heil, A.; Andreae, M. O.; Benedetti, A.; Chubarova, N.; Jones, L.; Morcrette, J.-J.; Razinger, M.; Schultz, M. G.; Suttie, M.; van der Werf, G. R.

    2012-01-01

    The Global Fire Assimilation System (GFASv1.0) calculates biomass burning emissions by assimilating Fire Radiative Power (FRP) observations from the MODIS instruments onboard the Terra and Aqua satellites. It corrects for gaps in the observations, which are mostly due to cloud cover, and filters spurious FRP observations of volcanoes, gas flares and other industrial activity. The combustion rate is subsequently calculated with land cover-specific conversion factors. Emission factors for 40 gas-phase and aerosol trace species have been compiled from a literature survey. The corresponding daily emissions have been calculated on a global 0.5° × 0.5° grid from 2003 to the present. General consistency with the Global Fire Emission Database version 3.1 (GFED3.1) within its accuracy is achieved while maintaining the advantages of an FRP-based approach: GFASv1.0 makes use of the quantitative information on the combustion rate that is contained in the FRP observations, and it detects fires in real time at high spatial and temporal resolution. GFASv1.0 indicates omission errors in GFED3.1 due to undetected small fires. It also exhibits slightly longer fire seasons in South America and North Africa and a slightly shorter fire season in Southeast Asia. GFASv1.0 has already been used for atmospheric reactive gas simulations in an independent study, which found good agreement with atmospheric observations. We have performed simulations of the atmospheric aerosol distribution with and without the assimilation of MODIS aerosol optical depth (AOD). They indicate that the emissions of particulate matter need to be boosted by a factor of 2-4 to reproduce the global distribution of organic matter and black carbon. This discrepancy is also evident in the comparison of previously published top-down and bottom-up estimates. For the time being, a global enhancement of the particulate matter emissions by 3.4 is recommended. Validation with independent AOD and PM10 observations recorded

  18. Aging assessment for active fire protection systems

    SciTech Connect

    Ross, S.B.; Nowlen, S.P.; Tanaka, T.

    1995-06-01

    This study assessed the impact of aging on the performance and reliability of active fire protection systems including both fixed fire suppression and fixed fire detection systems. The experience base shows that most nuclear power plants have an aggressive maintenance and testing program and are finding degraded fire protection system components before a failure occurs. Also, from the data reviewed it is clear that the risk impact of fire protection system aging is low. However, it is assumed that a more aggressive maintenance and testing program involving preventive diagnostics may reduce the risk impact even further.

  19. New Model Predicts Fire Activity in South America

    NASA Video Gallery

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

  20. Observations of marine stratocumulus clouds during FIRE

    NASA Technical Reports Server (NTRS)

    Albrecht, Bruce A.; Randall, David A.; Nicholls, Stephen

    1988-01-01

    The First International Satellite Cloud Climatology Project Regional Experiment (FIRE) to study extensive fields of stratocumulus clouds off the coast of California is presented. Measurements on the regional and detailed local scales were taken, allowing for a wide interpretation of the mean, turbulent, microphysical, radiative, and chemical characteristics of stratocumulus. Multiple aircraft and ground-based remote-sensing systems were used to study the time evolution of the boundary layer structure over a three-week period, and probes from tethered balloons were used to measure turbulence and to collect cloud-microphysical and cloud-radiative data. The observations provide a base for studying the generation maintenance and dissipation of stratocumulus clouds, and could aid in developing numerical models and improved methods for retrieving cloud properties by satellite.

  1. Remote Sensing of Fires and Smoke from the Earth Observing System MODIS Instrument

    NASA Technical Reports Server (NTRS)

    Kaufman, Y. J.; Hao, W. M.; Justice, C.; Giglio, L.; Herring, D.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    The talk will include review of the MODIS (Moderate Resolution Imaging Spectrometer) algorithms and performance e.g. the MODIS algorithm and the changes in the algorithm since launch. Comparison of MODIS and ASTER fire observations. Summary of the fall activity with the Forest Service in use of MODIS data for the fires in the North-West. Validation on the ground of the MODIS fire product.

  2. Management and climate contributions to satellite-derived active fire trends in the contiguous United States

    PubMed Central

    Lin, Hsiao-Wen; McCarty, Jessica L; Wang, Dongdong; Rogers, Brendan M; Morton, Douglas C; Collatz, G James; Jin, Yufang; Randerson, James T

    2014-01-01

    Fires in croplands, plantations, and rangelands contribute significantly to fire emissions in the United States, yet are often overshadowed by wildland fires in efforts to develop inventories or estimate responses to climate change. Here we quantified decadal trends, interannual variability, and seasonality of Terra Moderate Resolution Imaging Spectroradiometer (MODIS) observations of active fires (thermal anomalies) as a function of management type in the contiguous U.S. during 2001–2010. We used the Monitoring Trends in Burn Severity database to identify active fires within the perimeter of large wildland fires and land cover maps to identify active fires in croplands. A third class of fires defined as prescribed/other included all residual satellite active fire detections. Large wildland fires were the most variable of all three fire types and had no significant annual trend in the contiguous U.S. during 2001–2010. Active fires in croplands, in contrast, increased at a rate of 3.4% per year. Cropland and prescribed/other fire types combined were responsible for 77% of the total active fire detections within the U.S and were most abundant in the south and southeast. In the west, cropland active fires decreased at a rate of 5.9% per year, likely in response to intensive air quality policies. Potential evaporation was a dominant regulator of the interannual variability of large wildland fires, but had a weaker influence on the other two fire types. Our analysis suggests it may be possible to modify landscape fire emissions within the U.S. by influencing the way fires are used in managed ecosystems. Key Points Wildland, cropland, and prescribed fires had different trends and patterns Sensitivity to climate varied with fire type Intensity of air quality regulation influenced cropland burning trends PMID:26213662

  3. Impacts of changing fire weather conditions on reconstructed trends in U.S. wildland fire activity from 1979 to 2014

    NASA Astrophysics Data System (ADS)

    Freeborn, Patrick H.; Jolly, W. Matt; Cochrane, Mark A.

    2016-11-01

    One component of climate-fire interactions is the relationship between weather conditions concurrent with burning (i.e., fire danger) and the magnitude of fire activity. Here daily environmental conditions are associated with daily observations of fire activity within ecoregions across the continental United States (CONUS) by aligning the latter 12 years of a 36 year gridded fire danger climatology with the Moderate Resolution Imaging Spectroradiometer fire products. Results reveal that although modern relationships (2003-2014) vary regionally, fires across the majority of CONUS are more likely to be present and burning more vigorously as fire danger increases. Applying modern relationships to the entire climatology (1979-2014) indicates that in the absence of other influences, changes in fire danger have significantly increased the number of days per year that fires are burning across 42-49% of CONUS (by area) while also significantly increasing daily fire growth and daily heat release across 37-45% of CONUS. Increases in the fire activity season length coupled with an intensification of daily burning characteristics resulted in a CONUS-wide +0.02 Mha yr-1 trend in burned area, a 10.6 g m-2 yr-1 trend in the amount of fuel consumed per unit burned area, and ultimately a +0.51 Tg yr-1 trend in dry matter consumption. Overall, the results demonstrate regional variations in the response of fires to changes in fire danger and that weather conditions concurrent with burning have a three-pronged impact on the magnitude of fire activity by affecting the seasonal duration, spatial extent, and combustion intensity.

  4. Burned area, active fires and biomass burning - approaches to account for emissions from fires in Tanzania

    NASA Astrophysics Data System (ADS)

    Ruecker, Gernot; Hoffmann, Anja; Leimbach, David; Tiemann, Joachim; Ng'atigwa, Charles

    2013-04-01

    Eleven years of data from the globally available MODIS burned area and the MODS Active Fire Product have been analysed for Tanzania in conjunction with GIS data on land use and cover to provide a baseline for fire activity in this East African country. The total radiated energy (FRE) emitted by fires that were picked up by the burned area and active fire product is estimated based on a spatio-temporal clustering algorithm over the burned areas, and integration of the fire radiative power from the MODIS Active Fires product over the time of burning and the area of each burned area cluster. Resulting biomass combusted by unit area based on Woosteŕs scaling factor for FRE to biomass combusted is compared to values found in the literature, and to values found in the Global Fire Emissions Database (GFED). Pyrogenic emissions are then estimated using emission factors. According to our analysis, an average of 11 million ha burn annually (ranging between 8.5 and 12.9 million ha) in Tanzania corresponding to between 10 and 14 % of Tanzaniás land area. Most burned area is recorded in the months from May to October. The land cover types most affected are woodland and shrubland cover types: they comprise almost 70 % of Tanzania's average annual burned area or 6.8 million ha. Most burning occurs in gazetted land, with an annual average of 3.7 million ha in forest reserves, 3.3 million ha in game reserves and 1.46 million ha in national parks, totalling close to 8.5 million ha or 77 % of the annual average burned area of Tanzania. Annual variability of burned area is moderate for most of the analysed classes, and in most cases there is no clear trend to be detected in burned area, except for the Lindi region were annual burned area appears to be increasing. Preliminary results regarding emissions from fires show that for larger fires that burn over a longer time, biomass burned derived through the FRP method compares well to literature values, while the integration over

  5. Untrained Forward Observer (UFO) Translator for Call for Fire

    DTIC Science & Technology

    2013-09-01

    release; distribution is unlimited UNTRAINED FORWARD OBSERVER ( UFO ) TRANSLATOR FOR CALL FOR FIRE by Regan R. King September 2013 Thesis...DATE September 2013 3. REPORT TYPE AND DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE UNTRAINED FORWARD OBSERVER ( UFO ) TRANSLATOR FOR CALL...application, which we call the Untrained Forward Observer ( UFO ) Translator, capable of assisting untrained observers in performing Call for Fire by asking a

  6. 1. OVERVIEW SHOWING FIRING CONTROL BLOCKHOUSE 0502 AND ADJACENT OBSERVATION ...

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

    1. OVERVIEW SHOWING FIRING CONTROL BLOCKHOUSE 0502 AND ADJACENT OBSERVATION TOWER. WATER BRAKE TROUGH SEGMENT AT LOWER RIGHT. Looking north northeast. - Edwards Air Force Base, South Base Sled Track, Firing & Control Blockhouse for 10,000-foot Track, South of Sled Track at midpoint of 20,000-foot track, Lancaster, Los Angeles County, CA

  7. Management and climate contributions to satellite-derived active fire trends in the contiguous United States.

    PubMed

    Lin, Hsiao-Wen; McCarty, Jessica L; Wang, Dongdong; Rogers, Brendan M; Morton, Douglas C; Collatz, G James; Jin, Yufang; Randerson, James T

    2014-04-01

    Fires in croplands, plantations, and rangelands contribute significantly to fire emissions in the United States, yet are often overshadowed by wildland fires in efforts to develop inventories or estimate responses to climate change. Here we quantified decadal trends, interannual variability, and seasonality of Terra Moderate Resolution Imaging Spectroradiometer (MODIS) observations of active fires (thermal anomalies) as a function of management type in the contiguous U.S. during 2001-2010. We used the Monitoring Trends in Burn Severity database to identify active fires within the perimeter of large wildland fires and land cover maps to identify active fires in croplands. A third class of fires defined as prescribed/other included all residual satellite active fire detections. Large wildland fires were the most variable of all three fire types and had no significant annual trend in the contiguous U.S. during 2001-2010. Active fires in croplands, in contrast, increased at a rate of 3.4% per year. Cropland and prescribed/other fire types combined were responsible for 77% of the total active fire detections within the U.S and were most abundant in the south and southeast. In the west, cropland active fires decreased at a rate of 5.9% per year, likely in response to intensive air quality policies. Potential evaporation was a dominant regulator of the interannual variability of large wildland fires, but had a weaker influence on the other two fire types. Our analysis suggests it may be possible to modify landscape fire emissions within the U.S. by influencing the way fires are used in managed ecosystems.

  8. Detection, evaluation, and analysis of global fire activity using MODIS data

    NASA Astrophysics Data System (ADS)

    Giglio, Louis

    Global biomass burning plays a significant role in regional and global climate change, and spaceborne sensors offer the only practical way to monitor fire activity at these scales. This dissertation primarily concerns the development, evaluation, and use of the NASA Terra and Aqua MODIS instruments for fire monitoring. MODIS is the first satellite sensor designed specifically for global monitoring of fires. An improved operational fire detection algorithm was developed for the MODIS instrument. This algorithm offers a sensitivity to small, cool fires and minimizes false alarm rates. To support the accuracy assessment of the MODIS global fire product, an operational fire detection algorithm was developed and evaluated for the ASTER instrument, which provides higher resolution observations coincident with the Terra MODIS. The unique data set of multi-year MODIS day and night fire observations was used to analyze the global distribution of biomass burning using five different temporal metrics which included, for the first time, mean fire radiative power, a measure of fire intensity. The metrics show the planetary extent, seasonality, and interannual variability of fire. Recognizing differences in fire activity between morning and afternoon overpasses, the impact of the diurnal cycle of fire activity was addressed using seven years of fire data from the VIRS sensor on-board the TRMM satellite. A strong diurnal cycle was found in all regions, with the time of peak burning varying between approximately 13:00 and 18:30 local time. Given interest in area burned among atmospheric chemical transport and carbon cycle modelers, a data set was developed utilizing the MODIS global fire and vegetation cover products to estimate monthly burned area at 1-degree spatial resolution. The methods, products and results presented in this thesis provide the global change research and fire management communities with products for global fire monitoring and are currently being used in the

  9. Combining satellite-based fire observations and ground-based lightning detections to identify lightning fires across the conterminous USA

    USGS Publications Warehouse

    Bar-Massada, A.; Hawbaker, T.J.; Stewart, S.I.; Radeloff, V.C.

    2012-01-01

    Lightning fires are a common natural disturbance in North America, and account for the largest proportion of the area burned by wildfires each year. Yet, the spatiotemporal patterns of lightning fires in the conterminous US are not well understood due to limitations of existing fire databases. Our goal here was to develop and test an algorithm that combined MODIS fire detections with lightning detections from the National Lightning Detection Network to identify lightning fires across the conterminous US from 2000 to 2008. The algorithm searches for spatiotemporal conjunctions of MODIS fire clusters and NLDN detected lightning strikes, given a spatiotemporal lag between lightning strike and fire ignition. The algorithm revealed distinctive spatial patterns of lightning fires in the conterminous US While a sensitivity analysis revealed that the algorithm is highly sensitive to the two thresholds that are used to determine conjunction, the density of fires it detected was moderately correlated with ground based fire records. When only fires larger than 0.4 km2 were considered, correlations were higher and the root-mean-square error between datasets was less than five fires per 625 km2 for the entire study period. Our algorithm is thus suitable for detecting broad scale spatial patterns of lightning fire occurrence, and especially lightning fire hotspots, but has limited detection capability of smaller fires because these cannot be consistently detected by MODIS. These results may enhance our understanding of large scale patterns of lightning fire activity, and can be used to identify the broad scale factors controlling fire occurrence.

  10. Exploiting the power law distribution properties of satellite fire radiative power retrievals: A method to estimate fire radiative energy and biomass burned from sparse satellite observations

    NASA Astrophysics Data System (ADS)

    Kumar, S. S.; Roy, D. P.; Boschetti, L.; Kremens, R.

    2011-10-01

    Instantaneous estimates of the power released by fire (fire radiative power, FRP) are available with satellite active fire detection products. The temporal integral of FRP provides an estimate of the fire radiative energy (FRE) that is related linearly to the amount of biomass burned needed by the atmospheric emissions modeling community. The FRE, however, is sensitive to satellite temporal and spatial FRP undersampling due to infrequent satellite overpasses, cloud and smoke obscuration, and failure to detect cool and/or small fires. Satellite FRPs derived over individual burned areas and fires have been observed to exhibit power law distributions. This property is exploited to develop a new way to derive FRE, as the product of the fire duration and the expected FRP value derived from the FRP power law probability distribution function. The method is demonstrated and validated by the use of FRP data measured with a dual-band radiometer over prescribed fires in the United States and by the use of FRP data retrieved from moderate resolution imaging spectroradiometer (MODIS) active-fire detections over Brazilian deforestation and Australian savanna fires. The biomass burned derived using the conventional FRP temporal integration and power law FRE estimation methods is compared with biomass burned measurements (prescribed fires) and available fuel load information reported in the literature (Australian and Brazilian fires). The results indicate that the FRE power law derivation method may provide more reliable burned biomass estimates under sparse satellite FRP sampling conditions and correct for satellite active-fire detection omission errors if the FRP power law distribution parameters and the fire duration are known.

  11. Synchronous fire activity in the tropical high Andes: an indication of regional climate forcing.

    PubMed

    Román-Cuesta, R M; Carmona-Moreno, C; Lizcano, G; New, M; Silman, M; Knoke, T; Malhi, Y; Oliveras, I; Asbjornsen, H; Vuille, M

    2014-06-01

    Global climate models suggest enhanced warming of the tropical mid and upper troposphere, with larger temperature rise rates at higher elevations. Changes in fire activity are amongst the most significant ecological consequences of rising temperatures and changing hydrological properties in mountainous ecosystems, and there is a global evidence of increased fire activity with elevation. Whilst fire research has become popular in the tropical lowlands, much less is known of the tropical high Andean region (>2000 masl, from Colombia to Bolivia). This study examines fire trends in the high Andes for three ecosystems, the Puna, the Paramo and the Yungas, for the period 1982-2006. We pose three questions: (i) is there an increased fire response with elevation? (ii) does the El Niño- Southern Oscillation control fire activity in this region? (iii) are the observed fire trends human driven (e.g., human practices and their effects on fuel build-up) or climate driven? We did not find evidence of increased fire activity with elevation but, instead, a quasicyclic and synchronous fire response in Ecuador, Peru and Bolivia, suggesting the influence of high-frequency climate forcing on fire responses on a subcontinental scale, in the high Andes. ENSO variability did not show a significant relation to fire activity for these three countries, partly because ENSO variability did not significantly relate to precipitation extremes, although it strongly did to temperature extremes. Whilst ENSO did not individually lead the observed regional fire trends, our results suggest a climate influence on fire activity, mainly through a sawtooth pattern of precipitation (increased rainfall before fire-peak seasons (t-1) followed by drought spells and unusual low temperatures (t0), which is particularly common where fire is carried by low fuel loads (e.g., grasslands and fine fuel). This climatic sawtooth appeared as the main driver of fire trends, above local human influences and fuel build

  12. Vortical structures in pool fires: Observation, speculation, and simulation

    SciTech Connect

    Tieszen, S.R.; Nicolette, V.F.; Gritzo, L.A.; Moya, J.L.; Holen, J.K.

    1996-11-01

    While all fires are complex and involve many phenomena, this report is limited to large, turbulent liquid-hydrocarbon pool fires. Large, liquid-hydrocarbon pool fires present a risk in petrochemical storage and processing facilities and transportation systems that contain large amounts of liquid hydrocarbons. This report describes observations, speculations, and numerical simulations of vortical structures in pool fires. Vortical structures are observed in fires with length scales ranging from those that bend millimeter-thick flame zones to those that entrain air many meters from the edge of the fire to its centerline. The authors propose that baroclinic vorticity generation is primarily responsible for production of rotational motion at small scale and that amalgamation is responsible for the production of large-scale rotational structures from the myriad of small-scale structures. Numerical simulations show that vortical structures having time-mean definitions can be resolved with a Reynolds-Average Navier-Stokes (RANS) approach. However, for vortical structures without time-mean definition, RANS is inappropriate, and another technique, such as Large Eddy Simulation (LES), should be employed. 39 refs., 52 figs., 3 tabs.

  13. 29 CFR 553.210 - Fire protection activities.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... charged with forest fire fighting responsibilities, and who direct or engage in (1) fire spotting or... 29 Labor 3 2010-07-01 2010-07-01 false Fire protection activities. 553.210 Section 553.210 Labor... OF THE FAIR LABOR STANDARDS ACT TO EMPLOYEES OF STATE AND LOCAL GOVERNMENTS Fire Protection and...

  14. Plans for the Sentinel-3 SLSTR Active Fire Product

    NASA Astrophysics Data System (ADS)

    Wooster, Martin; Xu, Weidong

    2010-05-01

    The Sea and Land Surface Temperature Radiometer (SLSTR) will fly on the ESA Sentinel-3 satellites as a follow-on to the highly successful ERS/ENVISAR (A)ATSR series of imaging radiometers. SLSTR has been designed to offer a series of new capabilities over and above those of the forunner instruments (including an increased number of spectral channels, a much wider swath width, and an increased revisit frequency) whist still maintaining the key characteristics of dual-view, high accuracy and high precision radiometry. Included in the SLSTR-design are two dedicated "fire channels" that will allow unsaturated thermal spectral radiance observations over even high intensity and/or large open vegetation fires. Data from these and the other spectral channels will be used to generate an operational near real-time SLSTR active fire detection and fire radiative power product, to be used for both scientific studies on wildfire causes, behaviour and effects, and also operational applications involved with forecasting the short-term atmospheric impact of wildfire smoke. This work will present the plans for the SLSTR fire product, including details of the algorithm design and performance analysis, and an evaluation of the ver1 algorithm using MODIS data of global fire events.

  15. Cirrus parameterization from the FIRE ER-2 observations

    NASA Technical Reports Server (NTRS)

    Spinhirne, James D.

    1990-01-01

    Primary goals for the FIRE field experiments were validation of satellite cloud retrievals and study of cloud radiation parameters. The radiometers and lidar observations which were acquired from the NASA ER-2 high altitude aircraft during the FIRE cirrus field study may be applied to derive quantities which would be applicable for comparison to satellite retrievals and to define the cirrus radiative characteristics. The analysis involves parameterization of the vertical cloud distribution and relative radiance effects. An initial case study from the 28 Oct. 1986 cirrus experiment has been carried out, and results from additional experiment days are to be reported. The observations reported are for 1 day. Analysis of the many other cirrus observation cases from the FIRE study show variability of results.

  16. Satellite observations of NOx and VOC emissions from fires

    NASA Astrophysics Data System (ADS)

    Zoogman, P.; Chance, K.; Huang, G.; Gonzalez Abad, G.; Miller, C. E.; Nowlan, C. R.; Liu, X.

    2015-12-01

    We present estimates of NOx, formaldehyde, and glyoxal emissions from biomass burning events derived from enhancements measured by OMI (Ozone Monitoring Instrument). Emissions from biomass burning can vary greatly both regionally and from event to event, but previous work has been unable to fully explain this variability. Satellite observations from OMI offer a powerful tool to observe biomass burning events by providing observations globally over a range of environmental conditions that effect emissions of NOx, formaldehyde, and glyoxal. We will expand on previous studies by using OMI measurements to investigate not only the dependence of the emissions of each of these species on fire intensity but also the dependence of the ratios of these species. Fire intensity is quantified by using fire radiative power quantified by the MODIS (Moderate-Resolution Imaging Spectrometer) satellite instrument. We also account for variation of emissions and their ratios due to available fuel loading and fire types, which are affected by regional (e.g. biome type) and meteorological (e.g. wind, temperature, rainfall) factors. Furthermore, in individual case studies we will constrain how the chemical processing of primary fire emissions effects the secondary formation of VOCs and ozone by exploiting the temporal and spatial evolution of these interspecies relationships.

  17. Vegetation shifts observed in arctic tundra 17 years after fire

    USGS Publications Warehouse

    Barrett, Kirsten; Rocha, Adrian V.; van de Weg, Martine Janet; Shaver, Gaius

    2012-01-01

    With anticipated climate change, tundra fires are expected to occur more frequently in the future, but data on the long-term effects of fire on tundra vegetation composition are scarce. This study addresses changes in vegetation structure that have persisted for 17 years after a tundra fire on the North Slope of Alaska. Fire-related shifts in vegetation composition were assessed from remote-sensing imagery and ground observations of the burn scar and an adjacent control site. Early-season remotely sensed imagery from the burn scar exhibits a low vegetation index compared with the control site, whereas the late-season signal is slightly higher. The range and maximum vegetation index are greater in the burn scar, although the mean annual values do not differ among the sites. Ground observations revealed a greater abundance of moss in the unburned site, which may account for the high early growing season normalized difference vegetation index (NDVI) anomaly relative to the burn. The abundance of graminoid species and an absence of Betula nana in the post-fire tundra sites may also be responsible for the spectral differences observed in the remotely sensed imagery. The partial replacement of tundra by graminoid-dominated ecosystems has been predicted by the ALFRESCO model of disturbance, climate and vegetation succession.

  18. Quantifying pyroconvective injection heights using observations of fire energy: sensitivity of spaceborne observations of carbon monoxide

    NASA Astrophysics Data System (ADS)

    Gonzi, S.; Palmer, P. I.; Paugam, R.; Wooster, M.; Deeter, M. N.

    2015-04-01

    We use observations of active fire area and fire radiative power (FRP) from the NASA Moderate Resolution Imaging Spectroradiometers (MODIS), together with a parameterized plume rise model, to estimate biomass burning injection heights during 2006. We use these injection heights in the GEOS-Chem (Goddard Earth Observing System Chemistry) atmospheric chemistry transport model to vertically distribute biomass burning emissions of carbon monoxide (CO) and to study the resulting atmospheric distribution. For 2006, we use over half a million FRP and fire area observations as input to the plume rise model. We find that convective heat fluxes and active fire area typically lie in the range of 1-100 kW m-2 and 0.001-100 ha, respectively, although in rare circumstances the convective heat flux can exceed 500 kW m-2. The resulting injection heights have a skewed probability distribution with approximately 80% of the injections remaining within the local boundary layer (BL), with occasional injection height exceeding 8 km. We do not find a strong correlation between the FRP-inferred surface convective heat flux and the resulting injection height, with environmental conditions often acting as a barrier to rapid vertical mixing even where the convective heat flux and active fire area are large. We also do not find a robust relationship between the underlying burnt vegetation type and the injection height. We find that CO columns calculated using the MODIS-inferred injection height (MODIS-INJ) are typically -9 to +6% different to the control calculation in which emissions are emitted into the BL, with differences typically largest over the point of emission. After applying MOPITT (Measurement of Pollution in the Troposphere) v5 scene-dependent averaging kernels we find that we are much less sensitive to our choice of injection height profile. The differences between the MOPITT and the model CO columns (max bias ~ 50%), due largely to uncertainties in emission inventories, are

  19. Mapping the Daily Progression of Large Wildland Fires Using MODIS Active Fire Data

    NASA Technical Reports Server (NTRS)

    Veraverbeke, Sander; Sedano, Fernando; Hook, Simon J.; Randerson, James T.; Jin, Yufang; Rogers, Brendan

    2013-01-01

    High temporal resolution information on burned area is a prerequisite for incorporating bottom-up estimates of wildland fire emissions in regional air transport models and for improving models of fire behavior. We used the Moderate Resolution Imaging Spectroradiometer (MODIS) active fire product (MO(Y)D14) as input to a kriging interpolation to derive continuous maps of the evolution of nine large wildland fires. For each fire, local input parameters for the kriging model were defined using variogram analysis. The accuracy of the kriging model was assessed using high resolution daily fire perimeter data available from the U.S. Forest Service. We also assessed the temporal reporting accuracy of the MODIS burned area products (MCD45A1 and MCD64A1). Averaged over the nine fires, the kriging method correctly mapped 73% of the pixels within the accuracy of a single day, compared to 33% for MCD45A1 and 53% for MCD64A1.

  20. Space-based observational constraints for 1-D fire smoke plume-rise models

    NASA Astrophysics Data System (ADS)

    Val Martin, Maria; Kahn, Ralph A.; Logan, Jennifer A.; Paugam, Ronan; Wooster, Martin; Ichoku, Charles

    2012-11-01

    We use a plume height climatology derived from space-based Multiangle Imaging Spectroradiometer (MISR) observations to evaluate the performance of a widely used plume-rise model. We initialize the model with assimilated meteorological fields from the NASA Goddard Earth Observing System and estimated fuel moisture content at the location and time of the MISR measurements. Fire properties that drive the plume-rise model are difficult to constrain, and we test the model with four estimates each of active fire area and total heat flux, obtained from Moderate Resolution Imaging Spectroradiometer (MODIS) fire radiative power (FRP) thermal anomalies available for each MISR plume and other empirical data. We demonstrate the degree to which the fire dynamical heat flux (related to active fire area and sensible heat flux) and atmospheric stability structure influence plume rise, although entrainment and possibly other less well constrained factors are also likely to be significant. Using atmospheric stability conditions, MODIS FRP, and MISR plume heights, we find that smoke plumes reaching high altitudes are characterized by higher FRP and weaker atmospheric stability conditions than those at low altitude, which tend to remain confined below the boundary layer, consistent with earlier results. However, over the diversity of conditions studied, the model simulations generally underestimate the plume height dynamic range observed by MISR and do not reliably identify plumes injected into the free troposphere, key information needed for atmospheric models to simulate smoke dispersion. We conclude that embedding in large-scale atmospheric studies an advanced plume-rise model using currently available fire constraints remains a difficult proposition, and we propose a simplified model that crudely constrains plume injection height based on two main physical factors for which some observational constraints often exist. Field experiments aimed at directly measuring fire and smoke

  1. Spatial and temporal dimensions of fire activity in the fire-prone eastern Canadian taiga.

    PubMed

    Erni, Sandy; Arseneault, Dominique; Parisien, Marc-André; Bégin, Yves

    2017-03-01

    The forest age mosaic is a fundamental attribute of the North American boreal forest. Given that fires are generally lethal to trees, the time since last fire largely determines the composition and structure of forest stands and landscapes. Although the spatiotemporal dynamics of such mosaics has long been assumed to be random under the overwhelming influence of severe fire weather, no long-term reconstruction of mosaic dynamics has been performed from direct field evidence. In this study, we use fire length as a proxy for fire extent across the fire-prone eastern Canadian taiga and systematically reconstruct the spatiotemporal variability of fire extent and fire intervals, as well as the resulting forest age along a 340-km transect for the 1840-2013 time period. Our results indicate an extremely active fire regime over the last two centuries, with an overall burn rate of 2.1% of the land area yr(-1) , mainly triggered by seasonal anomalies of high temperature and severe drought. However, the rejuvenation of the age mosaic was strongly patterned in space and time due to the intrinsically lower burn rates in wetland-dominated areas and, more importantly, to the much-reduced likelihood of burning of stands up to 50 years postfire. An extremely high burn rate of ~5% yr(-1) would have characterized our study region during the last century in the absence of such fuel age effect. Although recent burn rates and fire sizes are within their range of variability of the last 175 years, a particularly severe weather event allowed a 2013 fire to spread across a large fire refuge, thus shifting the abundance of mature and old forest to a historic low. These results provide reference conditions to evaluate the significance and predict the spatiotemporal dynamics and impacts of the currently strengthening fire activity in the North American boreal forest.

  2. VIIRS active fire detection in Siberian boreal forests

    NASA Astrophysics Data System (ADS)

    Shvetsov, Eugene; Ponomarev, Evgenii

    2015-04-01

    The Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi National Polar-orbiting Partnership (S-NPP) satellite provides 12h global coverage at spatial resolutions of 375 m and 750 m. Current operational VIIRS Active Fire Product builds on the Moderate Resolution Imaging Spectroradiometer (MODIS) Collection 4 fire algorithm applying the similar combination of tests to the corresponding VIIRS 750 m data. This study investigates the application of VIIRS fire detection approaches based on 750m and 375m data in boreal forests of Siberia. VIIRS active fire detection product is compared to current Terra/ Aqua MODIS 1 km active fire product (MOD14/ MYD14) and Landsat-8 images are used for visual interpretation of areas containing active biomass burning. We utilize two VIIRS active fire products: based on MODIS Collection 6 algorithm for 750m data, and based on fire algorithm for 375 m data proposed by Schroeder et al. (2014). Both day and night fire detections are used for the analysis. In the present study we consider large fires complexes in the Eastern Siberia which burned for several weeks in July and August of 2014. We perform the comparison using 0.25 x 0.25 degree grid on a daily basis. Another objective of this study is to investigate the consistency of fire radiative power (FRP) retrievals between MODIS active fire product and VIIRS active fire product and to include VIIRS data into fire radiative energy (FRE) calculation which is related linearly to the total biomass consumption and pyrogenic emissions.

  3. Contribution of Earth Observation and meteorological datasets for the design and development of a national fire risk assessment system (NFOFRAS)

    NASA Astrophysics Data System (ADS)

    Katagis, Thomas; Bliziotis, Dimitris; Liantinioti, Chrysa; Gitas, Ioannis Z.; Charalampopoulou, Betty

    2016-08-01

    During the past decades, forest fires have increased both in frequency and severity thus, increasing the life threats for people and environment and leading countries to spend vast amounts of resources in fighting forest fires. Besides anthropogenic activities, climatic and environmental changes are considered as driving factors affecting fire occurrence and vegetation succession. Especially in the Mediterranean region, the development and existence of effective tools and services is crucial for assisting pre-fire planning and preparedness. The collaborative project NFOFRAS aims at introducing an innovative and effective system for rating forest fire risk, and is based on existing technology and standards that have been developed by countries with a long and a very successful involvement in this field. During the first phase of the project a detailed documentation of the proposed methodology was composed. In addition, Earth Observation (EO) and meteorological datasets were utilized for producing accurate pre-fire measurements over a selected study area in Greece.

  4. Fires and Smoke Observed from the Earth Observing System MODIS Instrument: Products, Validation, and Operational Use

    NASA Technical Reports Server (NTRS)

    Kaufman, Y. J.; Ichoku, C.; Giglio, L.; Korontzi, S.; Chu, D. A.; Hao, W. M.; Justice, C. O.; Lau, William K. M. (Technical Monitor)

    2001-01-01

    The MODIS sensor, launched on NASA's Terra satellite at the end of 1999, was designed with 36 spectral channels for a wide array of land, ocean, and atmospheric investigations. MODIS has a unique ability to observe fires, smoke, and burn scars globally. Its main fire detection channels saturate at high brightness temperatures: 500 K at 4 microns and 400 K at 11 microns, which can only be attained in rare circumstances at the I kin fire detection spatial resolution. Thus, unlike other polar orbiting satellite sensors with similar thermal and spatial resolutions, but much lower saturation temperatures (e.g. AVHRR and ATSR), MODIS can distinguish between low intensity ground surface fires and high intensity crown forest fires. Smoke column concentration over land is for the first time being derived from the MOMS solar channels, extending from 0.41 microns to 2.1 microns. The smoke product has been provisionally validated both globally and regionally over southern Africa and central and south America. Burn scars are observed from MODIS even in the presence of smoke, using the 1.2 to 2.1 micron channels. MODIS burned area information is used to estimate pyrogenic emissions. A wide range of these fire and related products and validation are demonstrated for the wild fires that occurred in northwestern United States in the summer of 2000. The MODIS rapid response system and direct broadcast capability is being developed to enable users to obtain and generate data in near real time. It is expected that health and land management organizations will use these systems for monitoring the occurrence of fires and the dispersion of smoke within two to six hours after data acquisition.

  5. Recent Extreme Forest Fire Activity in Western Russia: Fire Danger Conditions, Fire Behavior and Smoke Transport

    NASA Astrophysics Data System (ADS)

    Stocks, B. J.; Fromm, M.; Goldammer, J.; Carr, R.; Sukhinin, A. I.

    2010-12-01

    During the summer of 2010, widespread forest and peatland fires in western Russia burned over hundreds of thousands of hectares, burning over croplands, destroying hundreds of homes, and directly causing the death of more than 50 people. Unprecedented drought conditions, combined with an extended heat wave, resulted in extreme fire danger conditions and explosive fire behavior in a region of Russia not noted for large fires. Several fires exhibited pyroconvection, injecting smoke directly into the upper troposphere and lower stratosphere, while deep-burning fires created major regional smoke problems. This smoke persisted in the heavily-populated areas around Moscow, exposing millions to high levels of ozone and particulate matter, and creating both immediate and longer-term health risks. This presentation will explore the drought conditions leading to the catastrophic fire behavior experienced in western Russia, and analyze fire behavior in terms of fuel consumption, smoke production, fire intensity levels, and pyroconvection. Impacts of regional and long-range smoke transport will also be discussed.

  6. Atlantic SSTs control regime shifts in forest fire activity of Northern Scandinavia

    PubMed Central

    Drobyshev, Igor; Bergeron, Yves; Vernal, Anne de; Moberg, Anders; Ali, Adam A.; Niklasson, Mats

    2016-01-01

    Understanding the drivers of the boreal forest fire activity is challenging due to the complexity of the interactions driving fire regimes. We analyzed drivers of forest fire activity in Northern Scandinavia (above 60 N) by combining modern and proxy data over the Holocene. The results suggest that the cold climate in northern Scandinavia was generally characterized by dry conditions favourable to periods of regionally increased fire activity. We propose that the cold conditions over the northern North Atlantic, associated with low SSTs, expansion of sea ice cover, and the southward shift in the position of the subpolar gyre, redirect southward the precipitation over Scandinavia, associated with the westerlies. This dynamics strengthens high pressure systems over Scandinavia and results in increased regional fire activity. Our study reveals a previously undocumented teleconnection between large scale climate and ocean dynamics over the North Atlantic and regional boreal forest fire activity in Northern Scandinavia. Consistency of the pattern observed annually through millennium scales suggests that a strong link between Atlantic SST and fire activity on multiple temporal scales over the entire Holocene is relevant for understanding future fire activity across the European boreal zone. PMID:26940995

  7. Atlantic SSTs control regime shifts in forest fire activity of Northern Scandinavia.

    PubMed

    Drobyshev, Igor; Bergeron, Yves; Vernal, Anne de; Moberg, Anders; Ali, Adam A; Niklasson, Mats

    2016-03-04

    Understanding the drivers of the boreal forest fire activity is challenging due to the complexity of the interactions driving fire regimes. We analyzed drivers of forest fire activity in Northern Scandinavia (above 60 N) by combining modern and proxy data over the Holocene. The results suggest that the cold climate in northern Scandinavia was generally characterized by dry conditions favourable to periods of regionally increased fire activity. We propose that the cold conditions over the northern North Atlantic, associated with low SSTs, expansion of sea ice cover, and the southward shift in the position of the subpolar gyre, redirect southward the precipitation over Scandinavia, associated with the westerlies. This dynamics strengthens high pressure systems over Scandinavia and results in increased regional fire activity. Our study reveals a previously undocumented teleconnection between large scale climate and ocean dynamics over the North Atlantic and regional boreal forest fire activity in Northern Scandinavia. Consistency of the pattern observed annually through millennium scales suggests that a strong link between Atlantic SST and fire activity on multiple temporal scales over the entire Holocene is relevant for understanding future fire activity across the European boreal zone.

  8. The Southern Annular Mode determines interannual and centennial-scale fire activity in temperate southwest Tasmania, Australia

    NASA Astrophysics Data System (ADS)

    Mariani, Michela; Fletcher, Michael-Shawn

    2016-02-01

    Southern Annular Mode (SAM) is the primary mode of atmospheric variability in the Southern Hemisphere. While it is well established that the current anthropogenic-driven trend in SAM is responsible for decreased rainfall in southern Australia, its role in driving fire regimes in this region has not been explored. We examined the connection between fire activity and SAM in southwest Tasmania, which lies in the latitudinal band of strongest correlation between SAM and rainfall in the Southern Hemisphere. We reveal that fire activity during a fire season is significantly correlated with the phase of SAM in the preceding year using superposed epoch analysis. We then synthesized new 14 charcoal records from southwest Tasmania spanning the last 1000 years, revealing a tight coupling between fire activity and SAM at centennial timescales, observing a multicentury increase in fire activity over the last 500 years and a spike in fire activity in the 21st century in response to natural and anthropogenic SAM trends.

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

    USGS Publications Warehouse

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

    1998-01-01

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

  10. Introduced annual grass increases regional fire activity across the arid western USA (1980-2009).

    PubMed

    Balch, Jennifer K; Bradley, Bethany A; D'Antonio, Carla M; Gómez-Dans, José

    2013-01-01

    Non-native, invasive grasses have been linked to altered grass-fire cycles worldwide. Although a few studies have quantified resulting changes in fire activity at local scales, and many have speculated about larger scales, regional alterations to fire regimes remain poorly documented. We assessed the influence of large-scale Bromus tectorum (hereafter cheatgrass) invasion on fire size, duration, spread rate, and interannual variability in comparison to other prominent land cover classes across the Great Basin, USA. We compared regional land cover maps to burned area measured using the Moderate Resolution Imaging Spectroradiometer (MODIS) for 2000-2009 and to fire extents recorded by the USGS registry of fires from 1980 to 2009. Cheatgrass dominates at least 6% of the central Great Basin (650 000 km(2) ). MODIS records show that 13% of these cheatgrass-dominated lands burned, resulting in a fire return interval of 78 years for any given location within cheatgrass. This proportion was more than double the amount burned across all other vegetation types (range: 0.5-6% burned). During the 1990s, this difference was even more extreme, with cheatgrass burning nearly four times more frequently than any native vegetation type (16% of cheatgrass burned compared to 1-5% of native vegetation). Cheatgrass was also disproportionately represented in the largest fires, comprising 24% of the land area of the 50 largest fires recorded by MODIS during the 2000s. Furthermore, multi-date fires that burned across multiple vegetation types were significantly more likely to have started in cheatgrass. Finally, cheatgrass fires showed a strong interannual response to wet years, a trend only weakly observed in native vegetation types. These results demonstrate that cheatgrass invasion has substantially altered the regional fire regime. Although this result has been suspected by managers for decades, this study is the first to document recent cheatgrass-driven fire regimes at a regional

  11. ENSO controls interannual fire activity in southeast Australia

    NASA Astrophysics Data System (ADS)

    Mariani, M.; Fletcher, M.-S.; Holz, A.; Nyman, P.

    2016-10-01

    El Niño-Southern Oscillation (ENSO) is the main mode controlling the variability in the ocean-atmosphere system in the South Pacific. While the ENSO influence on rainfall regimes in the South Pacific is well documented, its role in driving spatiotemporal trends in fire activity in this region has not been rigorously investigated. This is particularly the case for the highly flammable and densely populated southeast Australian sector, where ENSO is a major control over climatic variability. Here we conduct the first region-wide analysis of how ENSO controls fire activity in southeast Australia. We identify a significant relationship between ENSO and both fire frequency and area burnt. Critically, wavelet analyses reveal that despite substantial temporal variability in the ENSO system, ENSO exerts a persistent and significant influence on southeast Australian fire activity. Our analysis has direct application for developing robust predictive capacity for the increasingly important efforts at fire management.

  12. The AVHRR component of a long-term global active fire data record

    NASA Astrophysics Data System (ADS)

    Csiszar, I. A.; Giglio, L.; Schroeder, W.; Justice, C. O.

    2010-12-01

    The increased thermal signal in the 3.7 µm channel, together with radiometric measurements in the longwave and shortwave channels, enable the detection of thermal anomalies from AVHRR for a wide range of environmental and observing conditions. The AVHRR has been used worldwide for operational fire monitoring and for research purposes since at least the early 1990s. The long data record of AVHRR makes it an essential part of a long-term, multisensor record of fire activity. Fire Disturbance is an Essential Climate Variable (ECV) defined by the Global Climate Observing System (GCOS). Within the Fire Disturbance ECV, active fire occurrence is one of the supplementary variables. General requirements for long-term satellite-based data records for ECVs are articulated in the GCOS Climate Monitoring Principles for satellite measurements, which specify requirements both for observing systems and for product generation and distribution. In this paper we provide an overview of the history of fire monitoring from AVHRR, and the potential and limitations for establishing a long-term data record in the context of the GCOS Climate Monitoring Principles. Major sensor-related challenges include the relatively low saturation level of the 3.7 µm channel, the orbital drift of the early NOAA satellites and pixel geolocation inaccuracies. Additionally, fire detection requires full resolution observations and therefore the globally and systematically available Global Area Coverage (GAC) data are inadequate for global active fire monitoring. The need for the compilation and reprocessing of full resolution measurements from on-board Local Area Coverage (LAC) data and direct-readout High Resolution Picture Transmission (HRPT) receiving stations is articulated by the Fire Mapping and Monitoring Implementation Team of the Global Observation of Forest and Landcover Dynamics (GOFC-GOLD) program, in collaboration with the Committee on Earth Observation Satellites. As fire detection

  13. Early warning of active fire hotspots through NASA FIRMS fire information system

    NASA Astrophysics Data System (ADS)

    Ilavajhala, S.; Davies, D.; Schmaltz, J. E.; Murphy, K. J.

    2014-12-01

    Forest fires and wildfires can threaten ecosystems, wildlife, property, and often, large swaths of populations. Early warning of active fire hotspots plays a crucial role in planning, managing, and mitigating the damaging effects of wildfires. The NASA Fire Information for Resource Management System (FIRMS) has been providing active fire location information to users in easy-to-use formats for the better part of last decade, with a view to improving the alerting mechanisms and response times to fight forest and wildfires. FIRMS utilizes fires flagged as hotspots by the MODIS instrument flying aboard the Aqua and Terra satellites and sends early warning of detected hotspots via email in near real-time or as daily and weekly summaries. The email alerts can also be customized to send alerts for a particular region of interest, a country, or a specific protected area or park. In addition, a web mapping component, named "Web Fire Mapper" helps query and visualize hotspots. A newer version of Web Fire Mapper is being developed to enhance the existing visualization and alerting capabilities. Plans include supporting near real-time imagery from Aqua and Terra satellites to provide a more helpful context while viewing fires. Plans are also underway to upgrade the email alerts system to provide mobile-formatted messages and short text messages (SMS). The newer version of FIRMS will also allow users to obtain geo-located image snapshots, which can be imported into local GIS software by stakeholders to help further analyses. This talk will discuss the FIRMS system, its enhancements and its role in helping map, alert, and monitor fire hotspots by providing quick data visualization, querying, and download capabilities.

  14. Fire!

    ERIC Educational Resources Information Center

    Jones, Rebecca

    1996-01-01

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

  15. MISR and AirMISR Simultaneously Observe African Grassland Fires

    NASA Technical Reports Server (NTRS)

    2000-01-01

    These images of northeastern South Africa, near Kruger National Park, were acquired on September 7, 2000. The left image shows an 85-kilometer wide x 200-kilometer long area captured by MISR's aftward-viewing 45-degree camera. At lower left are the Drakensberg Mountains; to the east of this range a large burn scar with thin smoke plumes from still-smoldering fires is visible. Near the top of the image another large burn scar with an open-pit mine at its western edge can be seen. Other burn scars are scattered throughout the image.

    Just above the center of the lefthand image is a polygonal burn scar with a set of smoke plumes from actively burning fires at its southwestern tip. The righthand image, which is a 'zoomed-in' view of the area, was acquired almost simultaneously by MISR's airborne counterpart, AirMISR, aboard a NASA ER-2 high-altitude aircraft. AirMISR contains a single camera that rotates to different view angles; when this image was acquired the camera was pointed straight downward. Because the ER-2 aircraft flies at an altitude of 20 kilometers, whereas the Terra spacecraft orbits the Earth 700 kilometers above the ground, the AirMISR image has 35 times finer spatial resolution. The AirMISR image covers about 9 kilometers x 9 kilometers. Unlike the MISR view, the AirMISR data are in 'raw' form and processing to remove radiometric and geometric distortions has not yet been performed.

    Fires such as those shown in the images are deliberately set to burn off dry vegetation, and constitute a widespread agricultural practice in many parts of Africa. These MISR and AirMISR images are part of an international field, aircraft, and satellite data collection and analysis campaign known as SAFARI-2000, the Southern Africa Regional Science Initiative. SAFARI-2000 is designed, in part, to study the effects of large-scale human activities on the regional climate, meteorology, and ecosystems.

    MISR was built and is managed by NASA's Jet Propulsion Laboratory

  16. Human-caused fires limit convection in tropical Africa: First temporal observations and attribution

    NASA Astrophysics Data System (ADS)

    Tosca, M. G.; Diner, D. J.; Garay, M. J.; Kalashnikova, O. V.

    2015-08-01

    It is well established that smoke particles modify clouds, which in turn affects climate. However, no study has quantified the temporal dynamics of aerosol-cloud interactions with direct observations. Here for the first time, we use temporally offset satellite observations from northern Africa between 2006 and 2010 to quantitatively measure the effect of fire aerosols on convective cloud dynamics. We attribute a reduction in cloud fraction during periods of high aerosol optical depths to a smoke-driven inhibition of convection. We find that higher smoke burdens limit upward vertical motion, increase surface pressure, and increase low-level divergence—meteorological indicators of convective suppression. These results are corroborated by climate simulations that show a smoke-driven increase in regionally averaged shortwave tropospheric heating and decrease in convective precipitation during the fire season. Our results suggest that in tropical regions, anthropogenic fire initiates a positive feedback loop where increased aerosol emissions limit convection, dry the surface, and enable increased fire activity via human ignition.

  17. A comparison of remote sensing of active fires from MODIS and VIIRS

    NASA Astrophysics Data System (ADS)

    Csiszar, I.; Schroeder, W.; Giglio, L.; Ellicott, E.; Justice, C. O.

    2012-04-01

    The Moderate Resolution Imaging Spectroradiometer (MODIS) on board the NASA EOS Terra and Aqua satellites was the first sensor on medium-resolution polar orbiting missions with dedicated bands for the detection and characterization of high temperature objects, predominantly actively burning fires. The MODIS active fire data record now extends to over a decade and is a result of multiple re-processing of the data with improved algorithms resulting from extensive product validation. The active fire product from the Visible Infrared Imager Radiometer Suite (VIIRS) on the NPOESS Preparatory Project (NPP) satellite, launched on October 28, 2011, and on future JPSS (Joint Polar Satellite System) satellites, represents a continuation of the MODIS data record. VIIRS has capabilities for active fire detection and characterization for a broad range of fires, and observing and environmental conditions. While NPP and Aqua have similar orbital characteristics and compatible sampling of the diurnal cycle of fire activity, sensor differences result in inherent differences in the expected fire observations. The differences between the MODIS and VIIRS moderate resolution "M" band pixel sizes (nominally, 1km vs. 750m at nadir) lead to differences in the lower detection limits. The VIIRS along-scan aggregation scheme is aimed at reducing the increase of pixel size towards the edges of the swath and thus results in an overall improvement of performance for off-nadir conditions, but also in a more complex variation of detection limits with satellite view angle. In addition, spatial aggregation impacts within-pixel variation of contribution to the radiometric signal, which in turn impacts retrieval of the Fire Radiative Power. These issues can be analyzed by purely theoretical simulations and by a hybrid empirical-theoretical modeling framework that incorporates actual fire observations from higher spatial resolution sensors, such as the Advanced Spaceborne Thermal Emission and

  18. Satellite-observed photosynthetic trends across boreal North America associated with climate and fire disturbance

    PubMed Central

    Goetz, Scott J.; Bunn, Andrew G.; Fiske, Gregory J.; Houghton, R. A.

    2005-01-01

    We analyzed trends in a time series of photosynthetic activity across boreal North America over 22 years (1981 through 2003). Nearly 15% of the region displayed significant trends, of which just over half involved temperature-related increases in growing season length and photosynthetic intensity, mostly in tundra. In contrast, forest areas unaffected by fire during the study period declined in photosynthetic activity and showed no systematic change in growing season length. Stochastic changes across the time series were predominantly associated with a frequent and increasing fire disturbance regime. These trends have implications for the direction of feedbacks to the climate system and emphasize the importance of longer term synoptic observations of arctic and boreal biomes. PMID:16174745

  19. Satellite-observed photosynthetic trends across boreal North America associated with climate and fire disturbance.

    PubMed

    Goetz, Scott J; Bunn, Andrew G; Fiske, Gregory J; Houghton, R A

    2005-09-20

    We analyzed trends in a time series of photosynthetic activity across boreal North America over 22 years (1981 through 2003). Nearly 15% of the region displayed significant trends, of which just over half involved temperature-related increases in growing season length and photosynthetic intensity, mostly in tundra. In contrast, forest areas unaffected by fire during the study period declined in photosynthetic activity and showed no systematic change in growing season length. Stochastic changes across the time series were predominantly associated with a frequent and increasing fire disturbance regime. These trends have implications for the direction of feedbacks to the climate system and emphasize the importance of longer term synoptic observations of arctic and boreal biomes.

  20. The Yellowstone Fires as Observed by SIR-C SAR

    NASA Technical Reports Server (NTRS)

    Rignot, Eric; Despain, Don; Holecz, Francesco

    1996-01-01

    Covers SIR-C (Spaceborne Imaging Radar C) SAR (Synthetic Aperture Radar) imaging of the 1988 Yellowstone National Forest fires. Discusses some of the images and data collected, and some conclusions drawn from them about both the fires, and SIR-C SAR imaging capabilities.

  1. Advanced fire observation by the Intelligent Infrared Sensor prototype FOCUS on the International Space Station

    NASA Astrophysics Data System (ADS)

    Oertel, D.; Haschberger, P.; Tank, V.; Lanzl, F.; Zhukov, B.; Jahn, H.; Briess, K.; Lorenz, E.; Roeser, H.-P.; Ginati, A.; Tobehn, C.; Schulte in den Bäumen, J.; Christmann, U.

    1999-01-01

    Current and planned operational space-borne Earth observation systems provide spatially, radiometrically or temporally crude data for the detection and monitoring of high temperature phenomena on the surface of our planet. High Temperature Events (HTE) very often cause environmental disasters. Such HTE are forest and savannah fires, fires of open coal mines, volcanic activities and others (e.g. fires of oil wells, pipelines etc.). A simultaneous co-registration of a combination of infrared (IR) and visible (VIS) channels is the key for a reliable autonomous on-board detection of High Temperature Events (HTE) on Earth surface, such as vegetation fires and volcano eruptions. This is the main feature of the FOCUS experiment. Furthermore there are ecology-oriented objectives of the FOCUS experiment mainly related to spectrometric/imaging remote inspection and parameter extraction of selected HTEs, and to the assessment of some ecological consequences of HTEs, such as aerosol and gas emission. Based on own experimental work and supported by Co-Investigators from Italy, Greece, France, Spain, Russia and Germany, DLR proposed in 1997 to use the International Space Station (ISS) in its early utilization phase as a platform and test-bed for an Intelligent Infrared Sensor prototype FOCUS of a future Environmental Disaster Recognition Satellite System. FOCUS is considered by ESA as an important mission combining a number of proven technologies and observation techniques to provide the scientific and operational user community with key data for the classification and monitoring of forest fires. FOCUS was selected as one of five European ``Groupings'' to be flown as an externally mounted payload during the early utilisation phase of the ISS. The FOCUS Phase A Study will be performed by OHB-System, DLR and Zeiss from September 1998 until May 1999.

  2. Further observations on back-firing in the motor nerve fibres of a muscle during twitch contractions.

    PubMed Central

    Buller, A J; Proske, U

    1978-01-01

    1. The tension developed by a muscle in response to a single supramaximal nerve volley is often the sum of two contractions, the second resulting from re-excitation of some nerve terminals during the first contraction. Re-excitation or back-firing can be prevented if the muscle nerve is stimulated twice with the second volley arriving in the muscle at a time when muscle fibres are still refractory following the first volley (Brown & Matthews, 1960). 2. Back-firing has been studied here in the medial gastrocnemius muscle of the spinal cat and responses have been recorded, either representing the summed activity of the muscle's motor supply or discharges of single functional motor axons. 3. When stimulating at a distance from the muscle, the second of two shocks is effective in suppressing back-firing over a narrower range of stimulus intervals than when stimulating close to the muscle. 4. The amount of back-firing can be reduced by stretching the muscle. At a length corresponding to the optimum for a twitch little if any back-firing remains. 5. Measurements of threshold to electrical stimulation of single functional motor axons suggests that low threshold axons are more likely to show back-firing. In the majority of cases, most or all of the motor units in the muscle have to be active before back-firing can be observed. PMID:745126

  3. FIRE

    Atmospheric Science Data Center

    2017-03-16

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

  4. 105-DR Large Sodium Fire Facility closure activities evaluation report

    SciTech Connect

    Adler, J.G.

    1996-04-11

    This report evaluates the closure activities at the 105-DR Large Sodium Fire Facility. The evaluation compares these activities to the regulatory requirements and closure plan requirements. The report concludes that the areas identified in the closure plan can be clean closed. This report summarizes and evaluates the closure activities performed in support of partial closure of the 105-DR Large Sodium Fire Facility (LSFF). This evaluation will be used in assessing the condition of the 105-DR LSFF for the purpose of meeting the partial clean closure conditions described in the 105-DR Large Sodium Fire Facility Closure Plan (DOE-RL 1995). Based on the evaluation of the decontamination activities, sampling activities, and sample data, it is has been determined that the partial clean closure conditions for the 105-DR LSFF have been met.

  5. Relationship between the interannual variability of satellite-observed fires and sea surface temperature anomalies

    NASA Astrophysics Data System (ADS)

    Chen, Y.; Randerson, J. T.; Morton, D. C.; DeFries, R. S.; Collatz, G. J.; Kasibhatla, P. S.; Giglio, L.; Jin, Y.; Marlier, M.

    2011-12-01

    Fire is a worldwide phenomenon that occurs in multiple biomes and regions, and has large impacts on ecosystems, air quality, and global climate. High fire years are often associated with an extended dry season and anomalously low levels of precipitation. Sea surface temperatures (SST) may regulate the precipitation variability on land through teleconnections. Here we investigated the relationship between year-to-year changes in satellite-derived estimates of fire activity and SST anomalies. Using South America as an example, we demonstrated an approach to predict regional annual fire season severity with 3-5 month lead times. We found that the Oceanic Niño Index (ONI) was correlated with interannual fire activity in the eastern Amazon whereas the Atlantic Multidecadal Oscillation (AMO) index was more closely linked with fires in the southern and southwestern Amazon. We then extended this approach to examine the relationship between fire occurrences and SSTs for other important fire regions, using SST anomalies from different regions within the Pacific, Atlantic, and Indian Oceans. We determined regions where SST changes had significant impacts on the annual fire season severity, as well as the optimal lead times of fire prediction for each region. This study will be of use in several different ways to inform mitigation and adaptation strategies related to climate change.

  6. Vegetation stress and summer fire activity in Portugal

    NASA Astrophysics Data System (ADS)

    Carlos, DaCamara; Sílvia, Nunes

    2013-04-01

    Fire activity in Mediterranean Europe is closely related to the climatological background where the occurrence of rainy and mild winters, followed by warm and dry summers, may induce high levels of vegetation stress over the different regions making them prone to the occurrence of fire events. The aim of the present study is to investigate whether years of very high or very low levels of fire activity over forests in Portugal are linked to contrasting vegetation cycles associated to high and low degrees of vegetation stress during the summer season. The present study relies on time series of yearly amounts of burned areas provided by Instituto de Conservação da Natureza e das Florestas (ICNF), the national authority for forests as well as on monthly values of NDVI and of brightness temperature as obtained from the Mediterranean Extended Daily One Km AVHRR Data Set (MEDOKADS) product provided by the Free University of Berlin. Both datasets cover the 16-year period from 1990 to 2005. The area of forest is first identified by means of a k-means cluster analysis that is performed on climatological yearly means of NDVI and brightness temperature. Monthly means of NDVI and of brightness temperature are then evaluated over the area of forest and composites are made for severe and mild years of fire activity defined as those with yearly burned areas respectively above the third quartile and below the first quartile. The composite of severe years presents a brightness temperature cycle with values above average during spring and summer together with values of NDVI below average during summer, the behavior of both parameters providing an indication of vegetation stress. In contrast, the composite of mild years of fire activity presents an NDVI cycle with values well below average during spring, an indication of lack of biomass, and a brightness temperature cycle with values below average during spring and summer, an indication that vegetation is not under stress. Results

  7. Global fire activity patterns (1996-2006) and climatic influence: an analysis using the World Fire Atlas

    NASA Astrophysics Data System (ADS)

    Le Page, Y.; Pereira, J. M. C.; Trigo, R.; da Camara, C.; Oom, D.; Mota, B.

    2008-04-01

    Vegetation fires have been acknowledged as an environmental process of global scale, which affects the chemical composition of the troposphere, and has profound ecological and climatic impacts. However, considerable uncertainty remains, especially concerning intra and inter-annual variability of fire incidence. The main goals of our global-scale study were to characterise spatial-temporal patterns of fire activity, to identify broad geographical areas with similar vegetation fire dynamics, and to analyse the relationship between fire activity and the El Niño-Southern Oscillation. This study relies on 10 years (mid 1996-mid 2006) of screened European Space Agency World Fire Atlas (WFA) data, obtained from Along Track Scanning Radiometer (ATSR) and Advanced ATSR (AATSR) imagery. Empirical Orthogonal Function analysis was used to reduce the dimensionality of the dataset. Regions of homogeneous fire dynamics were identified with cluster analysis, and interpreted based on their eco-climatic characteristics. The impact of 1997-1998 El Niño is clearly dominant over the study period, causing increased fire activity in a variety of regions and ecosystems, with variable timing. Overall, this study provides the first global decadal assessment of spatial-temporal fire variability and confirms the usefulness of the screened WFA for global fire ecoclimatology research.

  8. Vorticity and turbulence observations during a wildland fire on sloped terrain

    NASA Astrophysics Data System (ADS)

    Contezac, J.; Clements, C. B.; Hall, D.; Seto, D.; Davis, B.

    2013-12-01

    that winds were continuing to transport heat towards the slope. As the winds shifted with the fire whirl, heat flux values returned to ambient indicating the passage of the fire plume. A 0.15 hPa decrease in pressure was also observed at the first tower during this period. Further analyses to be presented include vorticity estimates from the Doppler lidar and turbulence kinetic energy measurements from the in situ towers.

  9. Obtaining a Pragmatic Representation of Fire Disturbance in Dynamic Vegetation Models by Assimilating Earth Observation Data

    NASA Astrophysics Data System (ADS)

    Kantzas, Euripides; Quegan, Shaun

    2015-04-01

    Fire constitutes a violent and unpredictable pathway of carbon from the terrestrial biosphere into the atmosphere. Despite fire emissions being in many biomes of similar magnitude to that of Net Ecosystem Exchange, even the most complex Dynamic Vegetation Models (DVMs) embedded in IPCC General Circulation Models poorly represent fire behavior and dynamics, a fact which still remains understated. As DVMs operate on a deterministic, grid cell-by-grid cell basis they are unable to describe a host of important fire characteristics such as its propagation, magnitude of area burned and stochastic nature. Here we address these issues by describing a model-independent methodology which assimilates Earth Observation (EO) data by employing image analysis techniques and algorithms to offer a realistic fire disturbance regime in a DVM. This novel approach, with minimum model restructuring, manages to retain the Fire Return Interval produced by the model whilst assigning pragmatic characteristics to its fire outputs thus allowing realistic simulations of fire-related processes such as carbon injection into the atmosphere and permafrost degradation. We focus our simulations in the Arctic and specifically Canada and Russia and we offer a snippet of how this approach permits models to engage in post-fire dynamics hitherto absent from any other model regardless of complexity.

  10. Estimating Landscape Fire Particulate Matter (PM) Emissions over Southern Africa using MSG-SEVIRI Fire Radiative Power (FRP) and MODIS Aerosol Optical Thickness Observations

    NASA Astrophysics Data System (ADS)

    Mota, Bernardo; Wooster, Martin J.

    2016-04-01

    The approach to estimating landscape fire fuel consumption based on the remotely sensed fire radiative power (FRP) thermal energy release rate, as opposed to burned area, is now relatively widely used in studies of fire emissions, including operationally within the Copernicus Atmosphere Monitoring Service (CAMS). Nevertheless, there are still limitations to the approach, including uncertainties associated with using only the few daily overpasses typically provided by polar orbiting satellite systems, the conversion between FRP and smoke emissions, and the increased likelihood that the more frequent data from geostationary systems fails to detect the (probably highly numerous) smaller (i.e. low FRP) component of a regions fire regime. In this study, we address these limitations to directly estimate fire emissions of Particular Matter (PM; or smoke aerosols) by presenting an approach combining the "bottom-up" FRP observations available every 15 minutes across Africa from the Meteosat Spinning Enhanced Visible and Infrared Imager (SEVIRI) Fire Radiative Product (FRP) processed at the EUMETSAT LSA SAF, and the "top-down" aerosol optical thickness (AOT) measures of the fire plumes themselves as measured by the Moderate-resolution Imaging Spectro-radiometer (MODIS) sensors aboard the Terra (MOD04_L2) and Aqua (MYD04_L2) satellites. We determine PM emission coefficients that relate directly to FRP measures by combining these two datasets, and the use of the almost continuous geostationary FRP observations allows us to do this without recourse to (uncertain) data on wind speed at the (unknown) height of the matching plume. We also develop compensation factors to address the detection limitations of small/low intensity (low FRP) fires, and remove the need to estimate fuel consumption by going directly from FRP to PM emissions. We derive the smoke PM emissions coefficients per land cover class by comparing the total fire radiative energy (FRE) released from individual fires

  11. Fire emissions simulated by prescribing burned area observations in a global vegetation model

    NASA Astrophysics Data System (ADS)

    Khlystova, Iryna G.; Wilkenskjeld, Stiig; Kloster, Silvia

    2014-05-01

    The emissions of trace gases and aerosols from large vegetation fires into the atmosphere have an important climate impact. In this study we integrate observed burned area into a global vegetation model to derive global fire emissions. A global continuous burned area products provided by GFED (Global Fire Emissions Dataset) were obtained from MODIS (and pre-MODIS) satellites and are available for the time period 1997-2011. We integrate the global burned area product into the global vegetation model JSBACH, a land part of the Earth-System model developed at the Max Planck Institute for Meteorology. JSBACH simulates land biomass in terms of carbon, which can be combined with the satellite burned area information to derive fire carbon emissions. Some assumptions on fire fuel consumptions have to be made during the integration of satellite burned area into the JSBACH. This includes processes such as tree mortality and combustion completeness, i.e. how much of the vegetation biomass gets combusted during a fire. Partially, this information can be also obtained from measurements. In this study we follow closely the approach of GFED, incorporating also GFED supplemental information, to simulate fuel consumption in JSBACH. And we compare simulated by this approach fire carbon emissions with the fire emissions from GFED. Global vegetation models often use prescribed land cover maps. The simulated in the JSBACH vegetation biomass and thus the simulated fire carbon emissions critically depend on the land cover distribution. In our study we derive fire carbon emissions using two different land cover parameterizations, based on two different satellite datasets. We will present the results obtained from simulations using the JSBACH standard MODIS based vegetation distribution and compare them to the results derived using the recently released ESA CCI land cover satellite product to demonstrate the sensitivity of simulated fire carbon emissions to the underlying land cover

  12. Constraints on global fire activity vary across a resource gradient.

    PubMed

    Krawchuk, Meg A; Moritz, Max A

    2011-01-01

    We provide an empirical, global test of the varying constraints hypothesis, which predicts systematic heterogeneity in the relative importance of biomass resources to burn and atmospheric conditions suitable to burning (weather/climate) across a spatial gradient of long-term resource availability. Analyses were based on relationships between monthly global wildfire activity, soil moisture, and mid-tropospheric circulation data from 2001 to 2007, synthesized across a gradient of long-term averages in resources (net primary productivity), annual temperature, and terrestrial biome. We demonstrate support for the varying constraints hypothesis, showing that, while key biophysical factors must coincide for wildfires to occur, the relative influence of resources to burn and moisture/weather conditions on fire activity shows predictable spatial patterns. In areas where resources are always available for burning during the fire season, such as subtropical/tropical biomes with mid-high annual long-term net primary productivity, fuel moisture conditions exert their strongest constraint on fire activity. In areas where resources are more limiting or variable, such as deserts, xeric shrublands, or grasslands/savannas, fuel moisture has a diminished constraint on wildfire, and metrics indicating availability of burnable fuels produced during the antecedent wet growing seasons reflect a more pronounced constraint on wildfire. This macro-scaled evidence for spatially varying constraints provides a synthesis with studies performed at local and regional scales, enhances our understanding of fire as a global process, and indicates how sensitivity to future changes in temperature and precipitation may differ across the world.

  13. Force Protection for Fire Fighters: Warm Zone Operations at Paramilitary Style Active Shooter Incidents in a Multi-Hazard Environment as a Fire Service Core Competency

    DTIC Science & Technology

    2012-03-01

    Radiological, Nuclear, Explosive CFD Charlotte Fire Department EMS Emergency Medical Services FDNY Fire Department of New York FEMA...that not only the CFD [Charlotte Fire Department] but the fire service in general is not prepared to respond to ASI’s [Active Shooter Incidents] and...cooperatively. Police officers used their bullet resistant shields to protect fire fighters engaged in fire suppression until heat and smoke conditions forced

  14. Kinematic structure of a wildland fire plume observed by Doppler lidar

    NASA Astrophysics Data System (ADS)

    Charland, A. M.; Clements, C. B.

    2013-04-01

    Wildland fires present a challenging environment to make meteorological measurements. Observations in the vicinity of wildland fires are needed to better understand fire-atmosphere interactions and to provide data for the evaluation of coupled fire-atmosphere models. An observational study was conducted during a low-intensity prescribed fire in an area of complex terrain with grass fuels east of San José, California. A ground-based scanning Doppler lidar acquired radial wind velocities and backscatter intensity in and around the fire plume from multiple horizontal and vertical scans. The development of a convergence zone was consistently observed to exist downwind of the plume and was indicated by a decrease in radial velocity of 3-5 m s-1. Divergence calculations made from the lidar radial velocities showed that the magnitude of convergence ranged between -0.06 and -0.08 s-1 downwind of the plumes, while a maximum of -0.14 s-1 occurred within the plume near the fire front. Increased radial velocities were observed at the plume boundary, indicating fire-induced acceleration of the wind into the base of the convection column above the fire front. Thermodynamic measurements made with radiosondes showed the smoke plume had a potential temperature perturbation of 3.0 to 4.4 K and an increase in water vapor mixing ratio of 0.5 to 1.0 g kg-1. Plume heights determined from sequential range height indicator scans provided estimates of vertical velocity between 0.4 and 0.6 m s-1, representing the ambient background vertical velocity as the top of the plume likely reached equilibrium.

  15. A biophysical observation model for field potentials of networks of leaky integrate-and-fire neurons

    PubMed Central

    beim Graben, Peter; Rodrigues, Serafim

    2013-01-01

    We present a biophysical approach for the coupling of neural network activity as resulting from proper dipole currents of cortical pyramidal neurons to the electric field in extracellular fluid. Starting from a reduced three-compartment model of a single pyramidal neuron, we derive an observation model for dendritic dipole currents in extracellular space and thereby for the dendritic field potential (DFP) that contributes to the local field potential (LFP) of a neural population. This work aligns and satisfies the widespread dipole assumption that is motivated by the “open-field” configuration of the DFP around cortical pyramidal cells. Our reduced three-compartment scheme allows to derive networks of leaky integrate-and-fire (LIF) models, which facilitates comparison with existing neural network and observation models. In particular, by means of numerical simulations we compare our approach with an ad hoc model by Mazzoni et al. (2008), and conclude that our biophysically motivated approach yields substantial improvement. PMID:23316157

  16. A biophysical observation model for field potentials of networks of leaky integrate-and-fire neurons.

    PubMed

    Beim Graben, Peter; Rodrigues, Serafim

    2012-01-01

    We present a biophysical approach for the coupling of neural network activity as resulting from proper dipole currents of cortical pyramidal neurons to the electric field in extracellular fluid. Starting from a reduced three-compartment model of a single pyramidal neuron, we derive an observation model for dendritic dipole currents in extracellular space and thereby for the dendritic field potential (DFP) that contributes to the local field potential (LFP) of a neural population. This work aligns and satisfies the widespread dipole assumption that is motivated by the "open-field" configuration of the DFP around cortical pyramidal cells. Our reduced three-compartment scheme allows to derive networks of leaky integrate-and-fire (LIF) models, which facilitates comparison with existing neural network and observation models. In particular, by means of numerical simulations we compare our approach with an ad hoc model by Mazzoni et al. (2008), and conclude that our biophysically motivated approach yields substantial improvement.

  17. Late Holocene fire activity recorded in a Greenland ice core

    NASA Astrophysics Data System (ADS)

    Zennaro, P.; Barbante, C.; Kehrwald, N.; Zangrando, R.; Gambaro, A.; Gabrieli, J.

    2012-04-01

    The pyrolysis compounds from the thermal decomposition of cellulose during burning events are the dominant smoke tracers in continental airsheds. Important compounds from biomass burning include monosaccharide anhydrides (MAs). Levoglucosan is a MA produced by combusing cellulose at a temperatures of 300°C or greater. Ice cores contain these specific molecular markers and other pyrochemical evidence that provides much-needed information on the role of fire in regions with no existing data of past fire activity. Here, we use atmospheric and snow levoglucosan concentrations to trace fire emissions from a boreal forest fire source in the Canadian Shield through transport and deposition at Summit, Greenland (72°35'N 38°25' W, 3048 masl). Atmospheric and surface samples suggest that levoglucosan in snow can record biomass burning events up to 1000s of kilometers away. Levoglucosan does degrade by interacting with hydroxyl radicals in the atmosphere, but it is emitted in large quantities, allowing the use as a biomass burning tracer. These quantified atmospheric biomass burning emissions and associated parallel oxalate and levoglucosan peaks in snow pit samples validates levoglucosan as a proxy for past biomass burning in snow records and by extension in ice cores. The temporal and spatial resolution of chemical markers in ice cores matches the core in which they are measured. The spatial resolution of chemical markers in ice cores depends on the core location where low-latitude ice cores primarily reflect regional climate parameters, and polar ice cores integrate hemispheric signals. We present levoglucosan flux, and hence past fire activity, measured during the late Holocene in the NEEM, Greenland (77°27' N; 51°3'W, 2454 masl) ice core. We compare the NEEM results with multiple major Northern Hemisphere climate and cultural parameters.

  18. Validation of MODIS and SEVIRI Active Fire Monitoring products over Western Romania. Case study: Arad County

    NASA Astrophysics Data System (ADS)

    Oanea, Lavinia; Alina Ristea, Mihaela

    2014-05-01

    At the national level, the issue of wildfire monitoring represents a long debated topic. However, in the present situation, fire management requires various improvements in terms of detection, monitoring and post-fire analysis. The objectives of this study are to validate the data provided by MODIS (Terra and Aqua) Active Fire Monitoring and SEVIRI (MSG) FIR (Active Fire Monitoring) satellite products, with wildfires field data from The Romanian General Inspectorate for Emergency Situations (IGSU) (1), to chart the efficiency of satellite products in locating fires and study their strengths and weaknesses using a SWOT analysis (2). This is the initial step of a larger project that aims to implement an online Geographic Information System for fire management that will ease wildfire data manipulation and facilitate the decision making process. In order to do so, the current study objectives must be achieved. Our general strategy is to determine the consistency of direct (field measurements) and indirect (satellite data) observations. Depending on the amount of field information, the fire characteristics (location, frequency, extension area, moment of occurrence, type of fire, and others) will be studied through a statistical analysis. The products show some peculiar restrictiveness like spatial and temporal resolution. Specifically, we will process and interpret satellite products to identify wildfires according to the data from IGSU using specialized software. The case study for the application of these procedures is a set of fire events from Arad county - Romania, that occurred between 2007 and 2013. In order to do so, it is important to compare results from different sensors with field information through various methods and to use only consistent results. The results will play an important role in achieving the above mentioned informational system, which will integrate field information, satellite data and values of parameters that influence the evolution of

  19. Effect of the selective noradrenergic reuptake inhibitor reboxetine on the firing activity of noradrenaline and serotonin neurons.

    PubMed

    Szabo, S T; Blier, P

    2001-06-01

    Reboxetine is a non-tricyclic antidepressant with selective noradrenergic (NA) reuptake-blocking effects. The effects of acute and sustained administration of reboxetine, on the firing activity of locus coeruleus NA neurons and dorsal raphe 5-HT neurons, were assessed using in vivo extracellular unitary recording in rats anaesthetized with chloral hydrate. Reboxetine (0.1-1.25 mg/kg, i.v.) dose-dependently decreased the firing activity of NA neurons (ED50 = 480 +/- 14 microg/kg). A 2-day treatment with reboxetine at 1.25, 2.5, 5, or 10 mg/kg per day (using osmotic minipumps implanted subcutaneously) produced significant decreases of 52%, 68%, 81%, and 83%, respectively, of NA firing activity. When the reboxetine treatment (2.5 mg/kg per day) duration was prolonged to 7 days, a 66% decrease in NA firing activity was observed which further decreased to 80% after 21 days of treatment. In contrast, 5-HT neuron firing rate remained unaltered following short- and long-term reboxetine treatments. The suppressant effect of the alpha2-adrenoceptor agonist clonidine on the firing activity of NA neurons was unchanged in long-term reboxetine-treated rats, but its effect on the firing activity of 5-HT neurons was blunted. The enhancement of NA firing activity by the 5-HT1A agonist 8-OH-DPAT was abolished in long-term reboxetine-treated rats, whereas, the inhibitory effect of the 5-HT2 agonist DOI was attenuated by about three-fold. In conclusion, sustained NA reuptake blockade by reboxetine lead to profound alterations in the function of NA neurons and of 5-HT receptors modulating their firing activity.

  20. Application of MODIS-Derived Active Fire Radiative Energy to Fire Disaster and Smoke Pollution Monitoring

    NASA Technical Reports Server (NTRS)

    Ichoku, Charles; Kaufman, Yoram J.; Hao, Wei Min; Habib, Shahid

    2004-01-01

    The radiative energy emitted by large fires and the corresponding smoke aerosol loading are simultaneously measured from the MODIS sensor from both the Terra and Aqua satellites. Quantitative relationships between the rates of emission of fire radiative energy and smoke are being developed for different fire-prone regions of the globe. Preliminary results are presented. When fully developed, the system will enable the use of MODIS direct broadcast fire data for near real-time monitoring of fire strength and smoke emission as well as forecasting of fire progression and smoke dispersion, several hours to a few days in advance.

  1. Seasonal Comparison of Observed Water Vapor Enhancement in Prescribed Fire Smoke Plumes

    NASA Astrophysics Data System (ADS)

    Kiefer, C. M.; Clements, C. B.; Potter, B. E.; Strenfel, S. J.; Hiers, J. K.

    2009-12-01

    In situ measurements of temperature and relative humidity were obtained during multiple prescribed fires in a longleaf pine ecosystem at the Joseph W. Jones Ecological Research Center at Ichauway, Georgia in July 2008 and January 2009. A 10 m tower was constructed to capture fire front plume conditions, while radiosondes were launched so smoke plume characteristics aloft could be quantified. As soon as significant smoke from the fire was observed, radiosondes were launched downwind of the fire front and ascended directly into the smoke plumes. Radiosondes were also launched before and after each burn to obtain ambient background conditions. These two measurement platforms provide a unique dataset of smoke plume moisture to determine how moisture enhancement from fire smoke alters the dynamics of the plume. Additionally, seasonal variations in ambient environmental conditions seem to have had an impact on increased plume moisture. Comparisons between summer and winter, as well as tower and radiosonde data will be presented. Results show moisture enhancement occurred in both summer and winter prescribed fires, with tower based measurements capturing greater plume moisture than radiosonde measurements. Preliminary results show plume water vapor mixing ratio was on the order of 1-5 g kg-1 and 0.8-1.4 g kg-1 greater in the summer from tower and radiosonde data, respectively.

  2. Assessment of the Utility of the Advanced Himawari Imager to Detect Active Fire Over Australia

    NASA Astrophysics Data System (ADS)

    Hally, B.; Wallace, L.; Reinke, K.; Jones, S.

    2016-06-01

    Wildfire detection and attribution is an issue of importance due to the socio-economic impact of fires in Australia. Early detection of fires allows emergency response agencies to make informed decisions in order to minimise loss of life and protect strategic resources in threatened areas. Until recently, the ability of land management authorities to accurately assess fire through satellite observations of Australia was limited to those made by polar orbiting satellites. The launch of the Japan Meteorological Agency (JMA) Himawari-8 satellite, with the 16-band Advanced Himawari Imager (AHI-8) onboard, in October 2014 presents a significant opportunity to improve the timeliness of satellite fire detection across Australia. The near real-time availability of images, at a ten minute frequency, may also provide contextual information (background temperature) leading to improvements in the assessment of fire characteristics. This paper investigates the application of the high frequency observation data supplied by this sensor for fire detection and attribution. As AHI-8 is a new sensor we have performed an analysis of the noise characteristics of the two spectral bands used for fire attribution across various land use types which occur in Australia. Using this information we have adapted existing algorithms, based upon least squares error minimisation and Kalman filtering, which utilise high frequency observations of surface temperature to detect and attribute fire. The fire detection and attribution information provided by these algorithms is then compared to existing satellite based fire products as well as in-situ information provided by land management agencies. These comparisons were made Australia-wide for an entire fire season - including many significant fire events (wildfires and prescribed burns). Preliminary detection results suggest that these methods for fire detection perform comparably to existing fire products and fire incident reporting from relevant

  3. Observations of a seasonal cycle in NOx emissions from fires in the African savanna

    NASA Astrophysics Data System (ADS)

    Mebust, A. K.; Cohen, R. C.

    2012-12-01

    Nitrogen oxide (NOx) emissions from wildfires account for ~15% of the global total, inducing large fluctuations in the chemical production and loss rates of O3 and CH4 and thereby affecting Earth's radiative balance. NOx emissions from fires depend on fuel N content, combustion stage, and total biomass burned; sparse observations limit current understanding of the variability in these factors across biomes. Here we use satellite-based measurements to study emission coefficients (ECs), a value proportional to emission factors i.e. NOx emitted per unit of biomass burned, from fires in African savannas. NOx ECs decrease steadily across the fire season, rather than remaining constant as is currently assumed. We speculate that this is due to reallocation of nutrients, including N, to plant roots after the growing season. We account for the observed cycle in the GEOS-Chem chemical transport model to show the impacts on monthly tropospheric ozone.

  4. Circum-Mediterranean fire activity and climate changes during the mid Holocene environmental transition (8500-2500 cal yr BP)

    NASA Astrophysics Data System (ADS)

    Vannière, Boris; Power, Mitch J.; Roberts, Neil; Tinner, Willy; Carrión, José; Magny, Michel; Bartlein, Patrick

    2010-05-01

    In this contribution I will present a synthesis of mid- to late-Holocene fire activity from the Mediterranean basin and explore the linkages among fire, climate variability and seasonality, and people through several climatic and ecological transitions. Regional fire histories were created from 36 radiocarbon-dated sedimentary charcoal records, available from the Global Charcoal Database. During the mid-Holocene "Thermal Maximum", charcoal records from the northern Mediterranean suggest the region was more fire prone while records from the southern Mediterranean indicate a decrease in fire activity associated with wetter-than-present summers. A North-South partition at 40-43°N is apparent in the central and western Mediterranean. In the context of orbitally-induced summer insolation decrease, South Mediterranean wet conditions could be linked to the Afro-Asian summer monsoon which weakened after ca. 8000-6000 cal yr BP. Relatively abrupt changes in fire regime observed at ca. 5500-5000 cal yr BP may be associated to a threshold in this weakening influence of the orbitally-driven Afro-Asian monsoon strength. Charcoal records of past fire activity appear sensitive to both orbitally-forced climate changes and shorter lived excursions which may be related to cold events apparent in the North Atlantic record of ice-rafted debris. These results contradict former notions of gradual aridification of the entire region due to climatic forcing and/or human activities. In contrast, they suggest: 1) Teleconnections between the Mediterranean area and other climatic regions, in particular the North Atlantic and the low-latitude monsoon areas, influenced past fire regimes; 2) Gradual forcing, such as changes in orbital parameters, may have triggered more abrupt shifts in fire regime, either directly or indirectly through these teleconnections.

  5. Bootstrap testing for cross-correlation under low firing activity.

    PubMed

    González-Montoro, Aldana M; Cao, Ricardo; Espinosa, Nelson; Cudeiro, Javier; Mariño, Jorge

    2015-06-01

    A new cross-correlation synchrony index for neural activity is proposed. The index is based on the integration of the kernel estimation of the cross-correlation function. It is used to test for the dynamic synchronization levels of spontaneous neural activity under two induced brain states: sleep-like and awake-like. Two bootstrap resampling plans are proposed to approximate the distribution of the test statistics. The results of the first bootstrap method indicate that it is useful to discern significant differences in the synchronization dynamics of brain states characterized by a neural activity with low firing rate. The second bootstrap method is useful to unveil subtle differences in the synchronization levels of the awake-like state, depending on the activation pathway.

  6. Incorporating Anthropogenic Influences into Fire Probability Models: Effects of Human Activity and Climate Change on Fire Activity in California

    PubMed Central

    Batllori, Enric; Moritz, Max A.; Waller, Eric K.; Berck, Peter; Flint, Alan L.; Flint, Lorraine E.; Dolfi, Emmalee

    2016-01-01

    The costly interactions between humans and wildfires throughout California demonstrate the need to understand the relationships between them, especially in the face of a changing climate and expanding human communities. Although a number of statistical and process-based wildfire models exist for California, there is enormous uncertainty about the location and number of future fires, with previously published estimates of increases ranging from nine to fifty-three percent by the end of the century. Our goal is to assess the role of climate and anthropogenic influences on the state’s fire regimes from 1975 to 2050. We develop an empirical model that integrates estimates of biophysical indicators relevant to plant communities and anthropogenic influences at each forecast time step. Historically, we find that anthropogenic influences account for up to fifty percent of explanatory power in the model. We also find that the total area burned is likely to increase, with burned area expected to increase by 2.2 and 5.0 percent by 2050 under climatic bookends (PCM and GFDL climate models, respectively). Our two climate models show considerable agreement, but due to potential shifts in rainfall patterns, substantial uncertainty remains for the semiarid inland deserts and coastal areas of the south. Given the strength of human-related variables in some regions, however, it is clear that comprehensive projections of future fire activity should include both anthropogenic and biophysical influences. Previous findings of substantially increased numbers of fires and burned area for California may be tied to omitted variable bias from the exclusion of human influences. The omission of anthropogenic variables in our model would overstate the importance of climatic ones by at least 24%. As such, the failure to include anthropogenic effects in many models likely overstates the response of wildfire to climatic change. PMID:27124597

  7. Incorporating Anthropogenic Influences into Fire Probability Models: Effects of Human Activity and Climate Change on Fire Activity in California.

    PubMed

    Mann, Michael L; Batllori, Enric; Moritz, Max A; Waller, Eric K; Berck, Peter; Flint, Alan L; Flint, Lorraine E; Dolfi, Emmalee

    2016-01-01

    The costly interactions between humans and wildfires throughout California demonstrate the need to understand the relationships between them, especially in the face of a changing climate and expanding human communities. Although a number of statistical and process-based wildfire models exist for California, there is enormous uncertainty about the location and number of future fires, with previously published estimates of increases ranging from nine to fifty-three percent by the end of the century. Our goal is to assess the role of climate and anthropogenic influences on the state's fire regimes from 1975 to 2050. We develop an empirical model that integrates estimates of biophysical indicators relevant to plant communities and anthropogenic influences at each forecast time step. Historically, we find that anthropogenic influences account for up to fifty percent of explanatory power in the model. We also find that the total area burned is likely to increase, with burned area expected to increase by 2.2 and 5.0 percent by 2050 under climatic bookends (PCM and GFDL climate models, respectively). Our two climate models show considerable agreement, but due to potential shifts in rainfall patterns, substantial uncertainty remains for the semiarid inland deserts and coastal areas of the south. Given the strength of human-related variables in some regions, however, it is clear that comprehensive projections of future fire activity should include both anthropogenic and biophysical influences. Previous findings of substantially increased numbers of fires and burned area for California may be tied to omitted variable bias from the exclusion of human influences. The omission of anthropogenic variables in our model would overstate the importance of climatic ones by at least 24%. As such, the failure to include anthropogenic effects in many models likely overstates the response of wildfire to climatic change.

  8. Methamphetamine Regulation of Firing Activity of Dopamine Neurons.

    PubMed

    Lin, Min; Sambo, Danielle; Khoshbouei, Habibeh

    2016-10-05

    Methamphetamine (METH) is a substrate for the dopamine transporter that increases extracellular dopamine levels by competing with dopamine uptake and increasing reverse transport of dopamine via the transporter. METH has also been shown to alter the excitability of dopamine neurons. The mechanism of METH regulation of the intrinsic firing behaviors of dopamine neurons is less understood. Here we identified an unexpected and unique property of METH on the regulation of firing activity of mouse dopamine neurons. METH produced a transient augmentation of spontaneous spike activity of midbrain dopamine neurons that was followed by a progressive reduction of spontaneous spike activity. Inspection of action potential morphology revealed that METH increased the half-width and produced larger coefficients of variation of the interspike interval, suggesting that METH exposure affected the activity of voltage-dependent potassium channels in these neurons. Since METH has been shown to affect Ca(2+) homeostasis, the unexpected findings that METH broadened the action potential and decreased the amplitude of afterhyperpolarization led us to ask whether METH alters the activity of Ca(2+)-activated potassium (BK) channels. First, we identified BK channels in dopamine neurons by their voltage dependence and their response to a BK channel blocker or opener. While METH suppressed the amplitude of BK channel-mediated unitary currents, the BK channel opener NS1619 attenuated the effects of METH on action potential broadening, afterhyperpolarization repression, and spontaneous spike activity reduction. Live-cell total internal reflection fluorescence microscopy, electrophysiology, and biochemical analysis suggest METH exposure decreased the activity of BK channels by decreasing BK-α subunit levels at the plasma membrane.

  9. Canadian and Siberian Boreal Fire Activity during ARCTAS Spring and Summer Phases

    NASA Astrophysics Data System (ADS)

    Stocks, B. J.; Fromm, M. D.; Soja, A. J.; Servranckx, R.; Lindsey, D.; Hyer, E.

    2009-12-01

    The summer phase of ARCTAS (Arctic Research of the Composition of the Troposphere from Aircraft and Satellites) was designed specifically around forest fire activity in the Canadian boreal forest, and located in areas of northern Canada where summer forest fires are ubiquitous. Lightning fires are most often allowed to burn naturally in these regions, and a number of large free-burning fires in northern Saskatchewan in late June/early July 2008 provided excellent targets during the summer phase of ARCTAS. Smoke generated by a large number of early spring fires in Kazakhstan and southern Siberia unexpectedly made a significant contribution to arctic haze during the Alaska-based spring phase of ARCTAS, Numerous smoke plumes were sampled during the spring phase of ARCTAS, creating interest in the origin and characteristics of the fires in the source regions of East Asia. This presentation is designed to connect aircraft and satellite smoke chemistry/transport measurements with ground-based measurements of fire activity during the spring and summer phases of ARCTAS. The Canadian Forest Fire Danger Rating System (CFFDRS) is used to determine forest fire danger conditions in regions of fire activity, and these measurements are in turn used to project fire behavior characteristics. Fuel consumption, spread rates, and frontal fire intensity are calculated using the CFFDRS. Energy release rates at ground level are related to convection/smoke column development and smoke injection heights.

  10. Do monkey F5 mirror neurons show changes in firing rate during repeated observation of natural actions?

    PubMed

    Kilner, J M; Kraskov, A; Lemon, R N

    2014-03-01

    Mirror neurons were first discovered in area F5 of macaque monkeys. In humans, noninvasive studies have demonstrated an increased blood oxygen level-dependent (BOLD) signal in homologous motor areas during action observation. One approach to demonstrating that this indicates the existence of mirror neurons in humans has been to employ functional (f)MRI adaptation to test whether the same population of neurons is active during both observation and execution conditions. Although a number of human studies have reported fMRI adaptation in these areas, a recent study has shown that macaque mirror neurons do not attenuate their firing rate with two repetitions. Here we investigated whether mirror neurons modulate their firing rate when monkeys observed the same repeated natural action multiple times. We recorded from 67 mirror neurons in area F5 of two macaque monkeys while they observed an experimenter perform a reach-to-grasp action on a small food reward using a precision grip. Although no changes were detectable for the first two repetitions, we show that both the firing rate and the latency at which mirror neurons discharged during observation were subtly modulated by the repetition of the observed action over 7-10 trials. Significant adaption was mostly found in the period immediately before the grasp was performed. We also found that the local field potential activity in F5 (beta-frequency range, 16-23 Hz), which is attenuated during action observation, also showed systematic changes with repeated observation. These LFP changes occurred well in advance of the mirror neuron adaptation. We conclude that macaque mirror neurons can show intra-modal adaptation, but whether this is related to fMRI adaptation of the BOLD signal requires further investigation.

  11. Corticothalamic Activation Modulates Thalamic Firing Through Glutamate "Metabotropic" Receptors

    NASA Astrophysics Data System (ADS)

    McCormick, David A.; von Krosigk, Marcus

    1992-04-01

    The mammalian thalamus forms an obligatory relay for nearly all sensory information that reaches the cerebral cortex. The transmission of sensory information by the thalamus varies in a state-dependent manner, such that during slow wave sleep or drowsiness thalamic responsiveness is markedly reduced, whereas during the waking, attentive state transmission is enhanced. Although activation of brainstem inputs to thalamic neurons has long been assumed to underlie this gating of sensory transfer through the thalamus, numerically the largest input to thalamic relay neurons derives from layer VI cells of the cerebral cortex. Here we report that activation of corticothalamic fibers causes a prolonged excitatory postsynaptic potential in guinea pig dorsal lateral geniculate relay neurons resulting from the reduction of a potassium conductance, consistent with the activation of glutamatergic "metabotropic" receptors. This slow depolarization can switch firing of thalamic neurons from the burst firing mode, which is prevalent during slow wave sleep, to the single spike mode, which is prevalent during waking, thereby facilitating transmission of sensory information through the thalamus. This prolonged enhancement of thalamic transfer may allow the cerebral cortex to gate or control selective fields of sensory inputs in a manner that facilitates arousal, attention, and cognition.

  12. Observational evidence on the effects of mega-fires on the frequency of hydrogeomorphic hazards. The case of the Peloponnese fires of 2007 in Greece.

    PubMed

    Diakakis, M; Nikolopoulos, E I; Mavroulis, S; Vassilakis, E; Korakaki, E

    2017-08-15

    Even though rare, mega-fires raging during very dry and windy conditions, record catastrophic impacts on infrastructure, the environment and human life, as well as extremely high suppression and rehabilitation costs. Apart from the direct consequences, mega-fires induce long-term effects in the geomorphological and hydrological processes, influencing environmental factors that in turn can affect the occurrence of other natural hazards, such as floods and mass movement phenomena. This work focuses on the forest fire of 2007 in Peloponnese, Greece that to date corresponds to the largest fire in the country's record that burnt 1773km(2), causing 78 fatalities and very significant damages in property and infrastructure. Specifically, this work examines the occurrence of flood and mass movement phenomena, before and after this mega-fire and analyses different influencing factors to investigate the degree to which the 2007 fire and/or other parameters have affected their frequency. Observational evidence based on several data sources collected during the period 1989-2016 show that the 2007 fire has contributed to an increase of average flood and mass movement events frequency by approximately 3.3 and 5.6 times respectively. Fire affected areas record a substantial increase in the occurrence of both phenomena, presenting a noticeably stronger increase compared to neighbouring areas that have not been affected. Examination of the monthly occurrence of events showed an increase even in months of the year were rainfall intensity presented decreasing trends. Although no major land use changes has been identified and chlorophyll is shown to recover 2years after the fire incident, differences on the type of vegetation as tall forest has been substituted with lower vegetation are considered significant drivers for the observed increase in flood and mass movement frequency in the fire affected areas.

  13. Composition, size and cloud condensation nuclei activity of biomass burning aerosol from northern Australian savannah fires

    NASA Astrophysics Data System (ADS)

    Mallet, Marc D.; Cravigan, Luke T.; Milic, Andelija; Alroe, Joel; Ristovski, Zoran D.; Ward, Jason; Keywood, Melita; Williams, Leah R.; Selleck, Paul; Miljevic, Branka

    2017-03-01

    The vast majority of Australia's fires occur in the tropical north of the continent during the dry season. These fires are a significant source of aerosol and cloud condensation nuclei (CCN) in the region, providing a unique opportunity to investigate the biomass burning aerosol (BBA) in the absence of other sources. CCN concentrations at 0.5 % supersaturation and aerosol size and chemical properties were measured at the Australian Tropical Atmospheric Research Station (ATARS) during June 2014. CCN concentrations reached over 104 cm-3 when frequent and close fires were burning - up to 45 times higher than periods with no fires. Both the size distribution and composition of BBA appeared to significantly influence CCN concentrations. A distinct diurnal trend in the proportion of BBA activating to cloud droplets was observed, with an activation ratio of 40 ± 20 % during the night and 60 ± 20 % during the day. BBA was, on average, less hygroscopic during the night (κ = 0. 04 ± 0.03) than during the day (κ = 0.07 ± 0.05), with a maximum typically observed just before midday. Size-resolved composition of BBA showed that organics comprised a constant 90 % of the aerosol volume for aerodynamic diameters between 100 and 200 nm. While this suggests that the photochemical oxidation of organics led to an increase in the hygroscopic growth and an increase in daytime activation ratios, it does not explain the decrease in hygroscopicity after midday. Modelled CCN concentrations assuming typical continental hygroscopicities produced very large overestimations of up to 200 %. Smaller, but still significant, overpredictions up to ˜ 100 % were observed using aerosol mass spectrometer (AMS)- and hygroscopicity tandem differential mobility analyser (H-TDMA)-derived hygroscopicities as well as campaign night and day averages. The largest estimations in every case occurred during the night, when the small variations in very weakly hygroscopic species corresponded to large

  14. Vertical distribution of clouds over Hampton, Virginia observed by lidar under the ECLIPS and FIRE ETO programs

    NASA Technical Reports Server (NTRS)

    Vaughan, M. A.; Winker, D. M.

    1994-01-01

    Intensive cloud lidar observations have been made by NASA Langley Research Center during the two observation phases of the ECLIPS project. Less intensive but longer term observations have been conducted as part of the FIRE extended time observation (ETO) program since 1987. We present a preliminary analysis of the vertical distribution of clouds based on these observations. A mean cirrus thickness of just under 1 km has been observed with a mean altitude of about 80 percent of the tropopause height. Based on the lidar data, cirrus coverage was estimated to be just under 20 percent, representing roughly 50 percent of all clouds studied. Cirrus was observed to have less seasonal variation than lower clouds. Mid-level clouds are found to occur primarily in association with frontal activity.

  15. An algorithm to detect fire activity using Meteosat: fine tuning and quality assesment

    NASA Astrophysics Data System (ADS)

    Amraoui, M.; DaCamara, C. C.; Ermida, S. L.

    2012-04-01

    Hot spot detection by means of sensors on-board geostationary satellites allows studying wildfire activity at hourly and even sub-hourly intervals, an advantage that cannot be met by polar orbiters. Since 1997, the Satellite Application Facility for Land Surface Analysis has been running an operational procedure that allows detecting active fires based on information from Meteosat-8/SEVIRI. This is the so-called Fire Detection and Monitoring (FD&M) product and the procedure takes advantage of the temporal resolution of SEVIRI (one image every 15 min), and relies on information from SEVIRI channels (namely 0.6, 0.8, 3.9, 10.8 and 12.0 μm) together with information on illumination angles. The method is based on heritage from contextual algorithms designed for polar, sun-synchronous instruments, namely NOAA/AVHRR and MODIS/TERRAAQUA. A potential fire pixel is compared with the neighboring ones and the decision is made based on relative thresholds as derived from the pixels in the neighborhood. Generally speaking, the observed fire incidence compares well against hot spots extracted from the global daily active fire product developed by the MODIS Fire Team. However, values of probability of detection (POD) tend to be quite low, a result that may be partially expected by the finer resolution of MODIS. The aim of the present study is to make a systematic assessment of the impacts on POD and False Alarm Ratio (FAR) of the several parameters that are set in the algorithms. Such parameters range from the threshold values of brightness temperature in the IR3.9 and 10.8 channels that are used to select potential fire pixels up to the extent of the background grid and thresholds used to statistically characterize the radiometric departures of a potential pixel from the respective background. The impact of different criteria to identify pixels contaminated by clouds, smoke and sun glint is also evaluated. Finally, the advantages that may be brought to the algorithm by adding

  16. Contrasting Spatial Patterns in Active-Fire and Fire-Suppressed Mediterranean Climate Old-Growth Mixed Conifer Forests

    PubMed Central

    Fry, Danny L.; Stephens, Scott L.; Collins, Brandon M.; North, Malcolm P.; Franco-Vizcaíno, Ernesto; Gill, Samantha J.

    2014-01-01

    In Mediterranean environments in western North America, historic fire regimes in frequent-fire conifer forests are highly variable both temporally and spatially. This complexity influenced forest structure and spatial patterns, but some of this diversity has been lost due to anthropogenic disruption of ecosystem processes, including fire. Information from reference forest sites can help management efforts to restore forests conditions that may be more resilient to future changes in disturbance regimes and climate. In this study, we characterize tree spatial patterns using four-ha stem maps from four old-growth, Jeffrey pine-mixed conifer forests, two with active-fire regimes in northwestern Mexico and two that experienced fire exclusion in the southern Sierra Nevada. Most of the trees were in patches, averaging six to 11 trees per patch at 0.007 to 0.014 ha−1, and occupied 27–46% of the study areas. Average canopy gap sizes (0.04 ha) covering 11–20% of the area were not significantly different among sites. The putative main effects of fire exclusion were higher densities of single trees in smaller size classes, larger proportion of trees (≥56%) in large patches (≥10 trees), and decreases in spatial complexity. While a homogenization of forest structure has been a typical result from fire exclusion, some similarities in patch, single tree, and gap attributes were maintained at these sites. These within-stand descriptions provide spatially relevant benchmarks from which to manage for structural heterogeneity in frequent-fire forest types. PMID:24586472

  17. Contrasting spatial patterns in active-fire and fire-suppressed Mediterranean climate old-growth mixed conifer forests.

    PubMed

    Fry, Danny L; Stephens, Scott L; Collins, Brandon M; North, Malcolm P; Franco-Vizcaíno, Ernesto; Gill, Samantha J

    2014-01-01

    In Mediterranean environments in western North America, historic fire regimes in frequent-fire conifer forests are highly variable both temporally and spatially. This complexity influenced forest structure and spatial patterns, but some of this diversity has been lost due to anthropogenic disruption of ecosystem processes, including fire. Information from reference forest sites can help management efforts to restore forests conditions that may be more resilient to future changes in disturbance regimes and climate. In this study, we characterize tree spatial patterns using four-ha stem maps from four old-growth, Jeffrey pine-mixed conifer forests, two with active-fire regimes in northwestern Mexico and two that experienced fire exclusion in the southern Sierra Nevada. Most of the trees were in patches, averaging six to 11 trees per patch at 0.007 to 0.014 ha(-1), and occupied 27-46% of the study areas. Average canopy gap sizes (0.04 ha) covering 11-20% of the area were not significantly different among sites. The putative main effects of fire exclusion were higher densities of single trees in smaller size classes, larger proportion of trees (≥ 56%) in large patches (≥ 10 trees), and decreases in spatial complexity. While a homogenization of forest structure has been a typical result from fire exclusion, some similarities in patch, single tree, and gap attributes were maintained at these sites. These within-stand descriptions provide spatially relevant benchmarks from which to manage for structural heterogeneity in frequent-fire forest types.

  18. Multiplatform inversion of the 2013 Rim Fire smoke emissions using regional-scale modeling: important nocturnal fire activity, air quality, and climate impacts

    NASA Astrophysics Data System (ADS)

    Saide, P. E.; Peterson, D. A.; da Silva, A. M., Jr.; Ziemba, L. D.; Anderson, B.; Diskin, G. S.; Sachse, G. W.; Hair, J. W.; Butler, C. F.; Fenn, M. A.; Jimenez, J. L.; Campuzano Jost, P.; Dibb, J. E.; Yokelson, R. J.; Toon, B.; Carmichael, G. R.

    2014-12-01

    Large wildfire events are increasingly recognized for their adverse effects on air quality and visibility, thus providing motivation for improving smoke emission estimates. The Rim Fire, one of the largest events in California's history, produced a large smoke plume that was sampled by the Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) DC-8 aircraft with a full suite of in-situ and remote sensing measurements on 26-27 August 2013. We developed an inversion methodology which uses the WRF-Chem modeling system to constrain hourly fire emissions, using as initial estimates the NASA Quick Fire Emissions Dataset (QFED). This method differs from the commonly performed top-down estimates that constrain daily (or longer time scale) emissions. The inversion method is able to simultaneously improve the model fit to various SEAC4RS airborne measurements (e.g., organic aerosol, carbon monoxide (CO), aerosol extinction), ground based measurements (e.g., AERONET aerosol optical depth (AOD), CO), and satellite data (MODIS AOD) by modifying fire emissions and utilizing the information content of all these measurements. Preliminary results show that constrained emissions for a 6 day period following the largest fire growth are a factor 2-4 higher than the initial top-down estimates. Moreover, there is a tendency to increase nocturnal emissions by factors sometimes larger than 20, indicating that vigorous fire activity continued during the night. This deviation from a typical diurnal cycle is confirmed using geostationary satellite data. The constrained emissions also have a larger day-to-day variability than the initial emissions and correlate better to daily area burned estimates as observed by airborne infrared measurements (NIROPS). Experiments with the assimilation system show that performing the inversion using only satellite AOD data produces much smaller correction factors than when using all available data

  19. Fire activity as a function of fire-weather seasonal severity and antecedent climate across spatial scales in southern Europe and Pacific western USA

    NASA Astrophysics Data System (ADS)

    Urbieta, Itziar R.; Zavala, Gonzalo; Bedia, Joaquín; Gutiérrez, José M.; San Miguel-Ayanz, Jesús; Camia, Andrea; Keeley, Jon E.; Moreno, José M.

    2015-11-01

    Climate has a strong influence on fire activity, varying across time and space. We analyzed the relationships between fire-weather conditions during the main fire season and antecedent water-balance conditions and fires in two Mediterranean-type regions with contrasted management histories: five southern countries of the European Union (EUMED)(all fires); the Pacific western coast of the USA (California and Oregon, PWUSA)(national forest fires). Total number of fires (≥1 ha), number of large fires (≥100 ha) and area burned were related to mean seasonal fire weather index (FWI), number of days over the 90th percentile of the FWI, and to the standardized precipitation-evapotranspiration index (SPEI) from the preceding 3 (spring) or 8 (autumn through spring) months. Calculations were made at three spatial aggregations in each area, and models related first-difference (year-to-year change) of fires and FWI/climate variables to minimize autocorrelation. An increase in mean seasonal FWI resulted in increases in the three fire variables across spatial scales in both regions. SPEI contributed little to explain fires, with few exceptions. Negative water-balance (dry) conditions from autumn through spring (SPEI8) were generally more important than positive conditions (moist) in spring (SPEI3), both of which contributed positively to fires. The R2 of the models generally improved with increasing area of aggregation. For total number of fires and area burned, the R2 of the models tended to decrease with increasing mean seasonal FWI. Thus, fires were more susceptible to change with climate variability in areas with less amenable conditions for fires (lower FWI) than in areas with higher mean FWI values. The relationships were similar in both regions, albeit weaker in PWUSA, probably due to the wider latitudinal gradient covered in PWUSA than in EUMED. The large variance explained by some of the models indicates that large-scale seasonal forecast could help anticipating fire

  20. Fire and climate in Mongolia (1532-2010 Common Era)

    NASA Astrophysics Data System (ADS)

    Hessl, Amy E.; Brown, Peter; Byambasuren, Oyunsanaa; Cockrell, Shawn; Leland, Caroline; Cook, Ed; Nachin, Baatarbileg; Pederson, Neil; Saladyga, Thomas; Suran, Byambagerel

    2016-06-01

    Recent increases in wildland fire, warming temperatures, and land use change have coincided in many forested regions, making it difficult to parse causes of elevated fire activity. Here we use 20 multicentury fire scar chronologies (464 fire scar samples) from Mongolia to evaluate the role of climate forcing of fire in the context of livestock grazing and minimal fire suppression. We observe no change in fire return intervals post-1900; however, since the 1500s, periods of drought are coincident with more fire and shorter fire return intervals. We observe same year and some antecedent year effects of drought on fire, a pattern typical of semiarid forests elsewhere. During the instrumental period, drought remains an important driver of fire; however, limited fire activity in recent decades may be due to the coincidence of drought and intensive grazing that have synergized to reduce fuel continuity and fire spread.

  1. Analysis of the GOES 6.7 micrometer channel observations during FIRE 2

    NASA Technical Reports Server (NTRS)

    Soden, B. J.; Ackerman, S. A.; Starr, David

    1993-01-01

    Clouds form in moist environments. FIRE Phase II Cirrus Implementation Plan (August, 1990) noted the need for mesoscale measurements of upper tropospheric water vapor content. These measurements are needed for initializing and verifying numerical weather prediction models and for describing the environment in which cirrus clouds develop and dissipate. Various instruments where deployed to measure the water vapor amounts of the upper troposphere during FIRE II (e.g. Raman lidar, CLASS sonds and new cryogenic frost hygrometer on-board aircraft). The formation, maintenance and dissipation of cirrus clouds involve the time variation of the water budget of the upper troposphere. The GOES 6.7 mu m radiance observations are sensitive to the upper tropospheric relative humidity, and therefore proved extremely valuable in planning aircraft missions during the field phase of FIRE II. Warm 6.7 mu m equivalent black body temperatures indicate a relatively dry upper troposphere and were associated with regions generally free of cirrus clouds. Regions that were colder, implying more moisture was available may or may not have had cirrus clouds present. Animation of a time sequence of 6.7 mu m images was particularly useful in planning various FIRE missions. The 6.7 mu m observations can also be very valuable in the verification of model simulations and describing the upper tropospheric synoptic conditions. A quantitative analysis of the 6.7 mu m measurement is required to successfully incorporate these satellite observations into describing the upper tropospheric water vapor budget. Recently, Soden and Bretherton (1993) have proposed a method of deriving an upper tropospheric humidity based on observations from the GOES 6.7 mu m observations. The method is summarized in the next section. In their paper they compare their retrieval method to radiance simulations. Observations were also compared to ECMWF model output to assess the model performance. The FIRE experiment provides a

  2. Contribution of peat fires to the 2015 Indonesian fires

    NASA Astrophysics Data System (ADS)

    Kaiser, Johannes W.; Heil, Angelika; Wooster, Martin J.; van der Werf, Guido R.

    2016-04-01

    Indonesia experienced widespread fires and severe air quality degradation due to smoke during September and October 2015. The fires are thought to have originated from the combination of El-Niño-induced drought and human activities. Fires ignited for land clearing escaped into drained peatlands and burned until the onset of the monsoonal rain. In addition to the health impact, these fires are thought to have emitted large amounts of greenhouse gases, e.g. more than Japan over the entire year. The Copernicus Atmosphere Monitoring Service (CAMS) has detected and quantified the fires with the Global Fire Assimilation System (GFAS) and the smoke dispersion with the Chemistry-Integrated Forecasting System (C-IFS) in near real time. GFAS and C-IFS are constrained by satellite-based observations of fire and smoke constituents, respectively. The distinction between peat and above-ground fires is a crucial and difficult step in fire emission estimation as it introduces errors of up to one order of magnitude. Here, we quantify the contribution of peat fires to the total emission flux of the 2015 Indonesian fires by (1) using an improved peat map in GFAS and (2) analysing the observed diurnal cycle of the fire activity as represented in a new development for GFAS. Furthermore, we link the fires occurrence to economic activity by analysing the coincidence with concessions for palm oil plantations and other industrial forest uses.

  3. Using Macroscopic Charcoal to Reconstruct the Holocene Fire Activity of the Willamette Valley, Oregon and Washington

    NASA Astrophysics Data System (ADS)

    Walsh, M. K.; Whitlock, C.; Bartlein, P. J.; Pearl, C. A.

    2006-12-01

    High-resolution macroscopic charcoal analysis of two lacustrine records has revealed the Holocene fire activity of the Willamette Valley, located between the Coast and Cascade ranges of southwestern Washington and northwestern Oregon. The Willamette Valley experienced major environmental and cultural changes during the Holocene, however, its long-term fire history is poorly known. Of particular interest are shifts in fire activity that occurred in response to (1) millennial- and centennial-scale climate and vegetation changes (e.g., the Early Holocene warm period, the Little Ice Age) and (2) major shifts in human activity and population size (e.g., Native American population decline, Euro-American settlement). Macroscopic charcoal analysis of contiguous core samples was used to reconstruct fire activity at each site. Charcoal source (i.e., herbaceous or woody) was also determined based on particle morphology. Charcoal influx was decomposed into a peak component (which indicates fire episodes) and a background component (which indicates changes in burnable biomass). Charcoal records from Battle Ground Lake and Beaver Lake reveal major shifts in fire activity that are consistent with known changes in regional climate on orbital time scales. The Battle Ground Lake charcoal data, for example, show a general increase in fire frequency from the beginning of the Holocene to a maximum of ~18 fire episodes/1000 years at 6500 cal yr BP, associated with the early Holocene insolation maximum and its influence on summer drought, followed by a decrease to ~5 fire episodes/1000 years at present. Similar trends are indicated by the Beaver Lake charcoal data. Both records also indicate shifts in fire activity that suggest the possibility of anthropogenic burning, but at different times at each site. Additional records are being analyzed to examine the spatial and temporal patterns of fire activity across the Willamette Valley as a whole.

  4. Holocene fire activity in the Carpathian region: regional climate vs. local controls

    NASA Astrophysics Data System (ADS)

    Florescu, Gabriela; Feurdean, Angelica

    2015-04-01

    Introduction. Fire drives significant changes in ecosystem structure and function, diversity, species evolution, biomass dynamics and atmospheric composition. Palaeodata and model-based studies have pointed towards a strong connection between fire activity, climate, vegetation and people. Nevertheless, the relative importance of these factors appears to be strongly variable and a better understanding of these factors and their interaction needs a thorough investigation over multiple spatial (local to global) and temporal (years to millennia) scales. In this respect, sedimentary charcoal, associated with other proxies of climate, vegetation and human impact, represents a powerful tool of investigating changes in past fire activity, especially in regions with scarce fire dataset such as the CE Europe. Aim. To increase the spatial and temporal coverage of charcoal records and facilitate a more critical examination of the patterns, drivers and consequences of biomass burning over multiple spatial and temporal scales in CE Europe, we have investigated 6 fossil sequences in the Carpathian region (northern Romania). These are located in different geographical settings, in terms of elevation, vegetation composition, topography and land-use. Specific questions are: i) determine trends in timing and magnitude of fire activity, as well as similarities and differences between elevations; ii) disentangle the importance of regional from local controls in fire activity; iii) evaluate ecological consequences of fire on landscape composition, structure and diversity. Methods. We first determine the recent trends in fire activity (the last 150 years) from charcoal data and compare them with instrumental records of temperature, precipitation, site history and topography for a better understanding of the relationship between sedimentary charcoal and historical fire activity. We then statistically quantify centennial to millennial trends in fire activity (frequency, magnitude) based on

  5. Characterization of smoke plume emissions and dynamics from prescribed and wildland fires using high-resolution field observations and a coupled fire-atmosphere model

    NASA Astrophysics Data System (ADS)

    Yedinak, Kara M.

    Smoke plumes associated with wildland fires are difficult to characterize due to the non-linear behavior of the variables involved. Plume chemistry is largely modeled using emission factors to represent the relative trace gas and aerosol species emitted. Plume dynamics are modeled based on assumptions of plume vertical distribution and atmospheric dispersion. In the studies presented here, near and in-source measurements of emissions from prescribed burns are used to characterize the variability of emission factors from low-intensity fires. Emissions factors were found to be in the same range as those from other, similar studies in the literature and it appears that the emission factors may be sensitive to small differences in surface conditions such as fuel moisture, surface wind speed, and the ratio of live to dead fuels. We also used two coupled fire atmosphere models, which utilize the Weather Research and Forecasting (WRF) model called WRF-Fire and WRF-Sfire, to investigate the role that atmospheric stability plays in influencing plume rise as well as developing a technique for assessing plume rise and the vertical distribution of pollutants in regional air quality models. Plume heights, as well as rate of growth of the fire, were found to be sensitive to atmospheric stability while fire rate of spread was not. The plume center-of-mass technique was demonstrated to work well but has slightly low estimates compared to observations.

  6. (Star)bursts of FIRE: observational signatures of bursty star formation in galaxies

    NASA Astrophysics Data System (ADS)

    Sparre, Martin; Hayward, Christopher C.; Feldmann, Robert; Faucher-Giguère, Claude-André; Muratov, Alexander L.; Kereš, Dušan; Hopkins, Philip F.

    2017-04-01

    Galaxy formation models are now able to reproduce observed relations such as the relation between galaxies' star formation rates (SFRs) and stellar masses (M*) and the stellar-mass-halo-mass relation. We demonstrate that comparisons of the short-time-scale variability in galaxy SFRs with observational data provide an additional useful constraint on the physics of galaxy formation feedback. We apply SFR indicators with different sensitivity time-scales to galaxies from the Feedback in Realistic Environments (FIRE) simulations. We find that the SFR-M* relation has a significantly greater scatter when the Hα-derived SFR is considered compared with when the far-ultraviolet (FUV)-based SFR is used. This difference is a direct consequence of bursty star formation because the FIRE galaxies exhibit order-of-magnitude SFR variations over time-scales of a few Myr. We show that the difference in the scatter between the simulated Hα- and FUV-derived SFR-M* relations at z = 2 is consistent with observational constraints. We also find that the Hα/FUV ratios predicted by the simulations at z = 0 are similar to those observed for local galaxies except for a population of low-mass (M* ≲ 109.5 M⊙) simulated galaxies with lower Hα/FUV ratios than observed. We suggest that future cosmological simulations should compare the Hα/FUV ratios of their galaxies with observations to constrain the feedback models employed.

  7. Fire activity inside and outside protected areas in Sub-Saharan Africa: a continental analysis of fire and its implications for biodiversity and land management

    NASA Astrophysics Data System (ADS)

    Palumbo, Ilaria; Gregoire, Jean-Marie; Simonetti, Dario; Punga, Mihkel; Dubois, Gregoire

    2010-05-01

    Fire is an important ecological factor in many natural ecosystems. Without doubt one of the biomes with the highest fire activity in the world is the African savannah. Savannahs have evolved with fires since climate in these regions is characterized by definite dry and wet seasons that create the conditions for burning. During the wet months the herbaceous vegetation shows a quick growth, followed by a long dry period during which the abundant build-up of fine materials becomes highly flammable and most of fires occur. Animals and plants are adapted to these conditions and their lives depend on recurrent fires. In this context fire becomes an essential element to promote biodiversity and nature conservation. Park managers are using programmed fires as a tool to maintain the habitats and favorable conditions to the animal communities. Satellite products like burned areas and active fire maps are a valuable mean to analyze the fire activity and provide support to experts working for conservation and natural resource management. In the framework of the Digital Observatory for Protected Areas (DOPA), the MONDE group (Monitoring Natural Resources for Development) of the Joint Research Centre of the European Commission is using satellite products to analyze the fire occurrence and its effects on protected areas located in sub-Saharan Africa. Information on the fire activity was derived from the MODIS fire products (active fires and burned areas) and allows the DOPA to provide support to park managers as well as to experts working for conservation and natural resource management. We assessed 741 protected areas classified by the IUCN (International Union for Conservation of Nature) with a level of protection between class I and IV. The MODIS datasets are available since the year 2000 and were used to characterize the spatio-temporal distribution of fires over a period of 10 years. Information on fire activity was extracted for the protected areas and a 25km buffer zone

  8. Fire activity inside and outside protected areas in Sub-Saharan Africa: a continental analysis of fire and its implications for biodiversity and management

    NASA Astrophysics Data System (ADS)

    Palumbo, Ilaria; Gregoire, Jean-Marie; Simonetti, Dario; Punga, Mihkel; Dubois, Gregoire

    2010-05-01

    Fire is an important ecological factor in many natural ecosystems. Without doubt one of the biomes with the highest fire activity in the world is the African savannah. Savannahs have evolved with fires since climate in these regions is characterized by definite dry and wet seasons that create the conditions for burning. During the wet months the herbaceous vegetation shows a quick growth, followed by a long dry period during which the abundant build-up of fine materials becomes highly flammable and most of fires occur. Animals and plants are adapted to these conditions and their lives depend on recurrent fires. In this context fire becomes an essential element to promote biodiversity and nature conservation. Park managers are using programmed fires as a tool to maintain the habitats and favorable conditions to the animal communities. Satellite products like burned areas and active fire maps are a valuable mean to analyze the fire activity and provide support to experts working for conservation and natural resource management. In the framework of the Digital Observatory for Protected Areas (DOPA), the MONDE group (Monitoring Natural Resources for Development) of the Joint Research Centre of the European Commission is using satellite products to analyze the fire occurrence and its effects on protected areas located in sub-Saharan Africa. Information on the fire activity was derived from the MODIS fire products (active fires and burned areas) and allows the DOPA to provide support to park managers as well as to experts working for conservation and natural resource management. We assessed 741 protected areas classified by the IUCN (International Union for Conservation of Nature) with a level of protection between class I and IV. The MODIS datasets are available since the year 2000 and were used to characterize the spatio-temporal distribution of fires over a period of 10 years. Information on fire activity was extracted for the protected areas and a 25km buffer zone

  9. Holocene fire activity and vegetation response in South-Eastern Iberia

    NASA Astrophysics Data System (ADS)

    Gil-Romera, Graciela; Carrión, José S.; Pausas, Juli G.; Sevilla-Callejo, Miguel; Lamb, Henry F.; Fernández, Santiago; Burjachs, Francesc

    2010-05-01

    Since fire has been recognized as an essential disturbance in Mediterranean landscapes, the study of long-term fire ecology has developed rapidly. We have reconstructed a sequence of vegetation dynamics and fire changes across south-eastern Iberia by coupling records of climate, fire, vegetation and human activities. We calculated fire activity anomalies (FAAs) in relation to 3 ka cal BP for 10-8 ka cal BP, 6 ka cal BP, 4 ka cal BP and the present. For most of the Early to the Mid-Holocene uneven, but low fire events were the main vegetation driver at high altitudes where broadleaved and coniferous trees presented a highly dynamic post-fire response. At mid-altitudes in the mainland Segura Mountains, fire activity remained relatively stable, at similar levels to recent times. We hypothesize that coastal areas, both mountains and lowlands, were more fire-prone landscapes as biomass was more likely to have accumulated than in the inland regions, triggering regular fire events. The wet and warm phase towards the Mid-Holocene (between ca 8 and 6 ka cal BP) affected the whole region and promoted the spread of mesophytic forest co-existing with Pinus, as FAAs appear strongly negative at 6 ka cal BP, with a less important role of fire. Mid and Late Holocene landscapes were shaped by an increasing aridity trend and the rise of human occupation, especially in the coastal mountains where forest disappeared from ca 2 ka cal BP. Mediterranean-type vegetation (evergreen oaks and Pinus pinaster- halepensis types) showed the fastest post-fire vegetation dynamics over time.

  10. Effects of biotic feedback and harvest management on boreal forest fire activity under climate change.

    PubMed

    Krawchuk, Meg A; Cumming, Steve G

    2011-01-01

    Predictions of future fire activity over Canada's boreal forests have primarily been generated from climate data following assumptions that direct effects of weather will stand alone in contributing to changes in burning. However, this assumption needs explicit testing. First, areas recently burned can be less likely to burn again in the near term, and this endogenous regulation suggests the potential for self-limiting, negative biotic feedback to regional climate-driven increases in fire. Second, forest harvest is ongoing, and resulting changes in vegetation structure have been shown to affect fire activity. Consequently, we tested the assumption that fire activity will be driven by changes in fire weather without regulation by biotic feedback or regional harvest-driven changes in vegetation structure in the mixedwood boreal forest of Alberta, Canada, using a simulation experiment that includes the interaction of fire, stand dynamics, climate change, and clear cut harvest management. We found that climate change projected with fire weather indices calculated from the Canadian Regional Climate Model increased fire activity, as expected, and our simulations established evidence that the magnitude of regional increase in fire was sufficient to generate negative feedback to subsequent fire activity. We illustrate a 39% (1.39-fold) increase in fire initiation and 47% (1.47-fold) increase in area burned when climate and stand dynamics were included in simulations, yet 48% (1.48-fold) and 61% (1.61-fold) increases, respectively, when climate was considered alone. Thus, although biotic feedbacks reduced burned area estimates in important ways, they were secondary to the direct effect of climate on fire. We then show that ongoing harvest management in this region changed landscape composition in a way that led to reduced fire activity, even in the context of climate change. Although forest harvesting resulted in decreased regional fire activity when compared to unharvested

  11. How fire history, fire suppression practices and climate change affect wildfire regimes in Mediterranean landscapes.

    PubMed

    Brotons, Lluís; Aquilué, Núria; de Cáceres, Miquel; Fortin, Marie-Josée; Fall, Andrew

    2013-01-01

    Available data show that future changes in global change drivers may lead to an increasing impact of fires on terrestrial ecosystems worldwide. Yet, fire regime changes in highly humanised fire-prone regions are difficult to predict because fire effects may be heavily mediated by human activities We investigated the role of fire suppression strategies in synergy with climate change on the resulting fire regimes in Catalonia (north-eastern Spain). We used a spatially-explicit fire-succession model at the landscape level to test whether the use of different firefighting opportunities related to observed reductions in fire spread rates and effective fire sizes, and hence changes in the fire regime. We calibrated this model with data from a period with weak firefighting and later assess the potential for suppression strategies to modify fire regimes expected under different levels of climate change. When comparing simulations with observed fire statistics from an eleven-year period with firefighting strategies in place, our results showed that, at least in two of the three sub-regions analysed, the observed fire regime could not be reproduced unless taking into account the effects of fire suppression. Fire regime descriptors were highly dependent on climate change scenarios, with a general trend, under baseline scenarios without fire suppression, to large-scale increases in area burnt. Fire suppression strategies had a strong capacity to compensate for climate change effects. However, strong active fire suppression was necessary to accomplish such compensation, while more opportunistic fire suppression strategies derived from recent fire history only had a variable, but generally weak, potential for compensation of enhanced fire impacts under climate change. The concept of fire regime in the Mediterranean is probably better interpreted as a highly dynamic process in which the main determinants of fire are rapidly modified by changes in landscape, climate and

  12. Controls on interannual variability in lightning-caused fire activity in the western US

    NASA Astrophysics Data System (ADS)

    Abatzoglou, John T.; Kolden, Crystal A.; Balch, Jennifer K.; Bradley, Bethany A.

    2016-04-01

    Lightning-caused wildfires account for a majority of burned area across the western United States (US), yet lightning remains among the more unpredictable spatiotemporal aspects of the fire environment and a challenge for both modeling and managing fire activity. A data synthesis of cloud-to-ground lightning strikes, climate and fire data across the western US from 1992 to 2013 was conducted to better understand geographic variability in lightning-caused wildfire and the factors that influence interannual variability in lightning-caused wildfire at regional scales. Distinct geographic variability occurred in the proportion of fires and area burned attributed to lightning, with a majority of fires in the interior western US attributed to lightning. Lightning ignition efficiency was highest across the western portion of the region due to the concomitance of peak lightning frequency and annual nadir in fuel moisture in mid-to-late summer. For most regions the number of total and dry lightning strikes exhibited strong interannual correlation with the number of lightning-caused fires, yet were a poor predictor of area burned at regional scales. Commonality in climate-fire relationships for regional annual area burned by lightning- versus human-ignited fires suggests climate conditions, rather than lightning activity, are the predominant control of interannual variability in area burned by lightning-caused fire across much of the western US.

  13. Modeling the effects of fire severity and climate warming on active layer and soil carbon dynamics of black spruce forests across the landscape in interior Alaska

    USGS Publications Warehouse

    Genet, H.; McGuire, Anthony David; Barrett, K.; Breen, A.; Euskirchen, E.S.; Johnstone, J.F.; Kasischke, E.S.; Melvin, A.M.; Bennett, A.; Mack, M.C.; Rupp, T.S.; Schuur, A.E.G.; Turetsky, M.R.; Yuan, F.

    2013-01-01

    There is a substantial amount of carbon stored in the permafrost soils of boreal forest ecosystems, where it is currently protected from decomposition. The surface organic horizons insulate the deeper soil from variations in atmospheric temperature. The removal of these insulating horizons through consumption by fire increases the vulnerability of permafrost to thaw, and the carbon stored in permafrost to decomposition. In this study we ask how warming and fire regime may influence spatial and temporal changes in active layer and carbon dynamics across a boreal forest landscape in interior Alaska. To address this question, we (1) developed and tested a predictive model of the effect of fire severity on soil organic horizons that depends on landscape-level conditions and (2) used this model to evaluate the long-term consequences of warming and changes in fire regime on active layer and soil carbon dynamics of black spruce forests across interior Alaska. The predictive model of fire severity, designed from the analysis of field observations, reproduces the effect of local topography (landform category, the slope angle and aspect and flow accumulation), weather conditions (drought index, soil moisture) and fire characteristics (day of year and size of the fire) on the reduction of the organic layer caused by fire. The integration of the fire severity model into an ecosystem process-based model allowed us to document the relative importance and interactions among local topography, fire regime and climate warming on active layer and soil carbon dynamics. Lowlands were more resistant to severe fires and climate warming, showing smaller increases in active layer thickness and soil carbon loss compared to drier flat uplands and slopes. In simulations that included the effects of both warming and fire at the regional scale, fire was primarily responsible for a reduction in organic layer thickness of 0.06 m on average by 2100 that led to an increase in active layer thickness

  14. Modeling the effects of fire severity and climate warming on active layer thickness and soil carbon storage of black spruce forests across the landscape in interior Alaska

    SciTech Connect

    Genet, Helene; McGuire, A. David; Barrett, K.; Breen, Amy; Euskirchen, Eugenie S; Johnstone, J. F.; Kasischke, Eric S.; Melvin, A. M.; Bennett, A.; Mack, M. C.; Rupp, Scott T.; Schuur, Edward; Turetsky, M. R.; Yuan, Fengming

    2013-01-01

    There is a substantial amount of carbon stored in the permafrost soils of boreal forest ecosystems, where it is currently protected from decomposition. The surface organic horizons insulate the deeper soil from variations in atmospheric temperature. The removal of these insulating horizons through consumption by fire increases the vulnerability of permafrost to thaw, and the carbon stored in permafrost to decomposition. In this study we ask how warming and fire regime may influence spatial and temporal changes in active layer and carbon dynamics across a boreal forest landscape in interior Alaska. To address this question, we (1) developed and tested a predictive model of the effect of fire severity on soil organic horizons that depends on landscape-level conditions and (2) used this model to evaluate the long-term consequences of warming and changes in fire regime on active layer and soil carbon dynamics of black spruce forests across interior Alaska. The predictive model of fire severity, designed from the analysis of field observations, reproduces the effect of local topography (landform category, the slope angle and aspect and flow accumulation), weather conditions (drought index, soil moisture) and fire characteristics (day of year and size of the fire) on the reduction of the organic layercaused by fire. The integration of the fire severity model into an ecosystem process-based model allowed us to document the relative importance and interactions among local topography, fire regime and climate warming on active layer and soil carbon dynamics. Lowlands were more resistant to severe fires and climate warming, showing smaller increases in active layer thickness and soil carbon loss compared to drier flat uplands and slopes. In simulations that included the effects of both warming and fire at the regional scale, fire was primarily responsible for a reduction in organic layer thickness of 0.06 m on average by 2100 that led to an increase in active layer thickness

  15. Fire Activity and Severity in the Western US Vary along Proxy Gradients Representing Fuel Amount and Fuel Moisture

    PubMed Central

    Parks, Sean A.; Parisien, Marc-André; Miller, Carol; Dobrowski, Solomon Z.

    2014-01-01

    Numerous theoretical and empirical studies have shown that wildfire activity (e.g., area burned) at regional to global scales may be limited at the extremes of environmental gradients such as productivity or moisture. Fire activity, however, represents only one component of the fire regime, and no studies to date have characterized fire severity along such gradients. Given the importance of fire severity in dictating ecological response to fire, this is a considerable knowledge gap. For the western US, we quantify relationships between climate and the fire regime by empirically describing both fire activity and severity along two climatic water balance gradients, actual evapotranspiration (AET) and water deficit (WD), that can be considered proxies for fuel amount and fuel moisture, respectively. We also concurrently summarize fire activity and severity among ecoregions, providing an empirically based description of the geographic distribution of fire regimes. Our results show that fire activity in the western US increases with fuel amount (represented by AET) but has a unimodal (i.e., humped) relationship with fuel moisture (represented by WD); fire severity increases with fuel amount and fuel moisture. The explicit links between fire regime components and physical environmental gradients suggest that multivariable statistical models can be generated to produce an empirically based fire regime map for the western US. Such models will potentially enable researchers to anticipate climate-mediated changes in fire recurrence and its impacts based on gridded spatial data representing future climate scenarios. PMID:24941290

  16. Fire activity and severity in the western US vary along proxy gradients representing fuel amount and fuel moisture.

    PubMed

    Parks, Sean A; Parisien, Marc-André; Miller, Carol; Dobrowski, Solomon Z

    2014-01-01

    Numerous theoretical and empirical studies have shown that wildfire activity (e.g., area burned) at regional to global scales may be limited at the extremes of environmental gradients such as productivity or moisture. Fire activity, however, represents only one component of the fire regime, and no studies to date have characterized fire severity along such gradients. Given the importance of fire severity in dictating ecological response to fire, this is a considerable knowledge gap. For the western US, we quantify relationships between climate and the fire regime by empirically describing both fire activity and severity along two climatic water balance gradients, actual evapotranspiration (AET) and water deficit (WD), that can be considered proxies for fuel amount and fuel moisture, respectively. We also concurrently summarize fire activity and severity among ecoregions, providing an empirically based description of the geographic distribution of fire regimes. Our results show that fire activity in the western US increases with fuel amount (represented by AET) but has a unimodal (i.e., humped) relationship with fuel moisture (represented by WD); fire severity increases with fuel amount and fuel moisture. The explicit links between fire regime components and physical environmental gradients suggest that multivariable statistical models can be generated to produce an empirically based fire regime map for the western US. Such models will potentially enable researchers to anticipate climate-mediated changes in fire recurrence and its impacts based on gridded spatial data representing future climate scenarios.

  17. Increasing late winter-early spring fire activity in Northern Spain: climate change or human footprint?

    NASA Astrophysics Data System (ADS)

    Carracedo Martín, Virginia; García Codron, Juan Carlos; Rasilla Álvarez, Domingo

    2016-04-01

    Most of the fire activity across Spain concentrates during the summer months, but a secondary peak appears also during late winter and early spring (February and March). This peak represents a tiny fraction of the burned surface but in northern Spain becomes the main fire season, representing up to 60 % of the total burned surface. Moreover, the impact of this "unseasonal" fire regime is becoming more relevant; an analysis of the temporal evolution of the burned surface since 2005 shows that the suppression efforts of summer forest fires have apparently succeeded, while the opposite has occurred with late winter-early spring forest fires. For example, during March 2012 more than 22,000 ha were burned in the Spanish provinces of Asturias and Cantabria, while about 14,000 suffers the effects of fires in Northern Portugal. Anthropogenic factor (mostly linked to an extensive cattle farming in the mountains) are the main cause of such fire activity, but atmospheric factors also play a relevant role in the spread of this fires. Consequently, the main aim of this poster is to explore if the recent evolution of forest fires in the study area are consequence of an aggravation of the atmospheric conditions driving to more fire risk conditions, or other factor could also explain the increase in fire activity. Burned surface data obtained from official statistics since 1971 were compared with atmospheric data at two temporal scales: daily fire risk values calculated from synoptic records and long term drought indices (SPI and SPEI). The results show a long term increase in both daily fire risk and drought conditions, but this trend can be related to the background warming of the area, rather to an increase in the frequency and magnitude of the extreme fire weather events. Thus, we consider that the regional atmospheric evolution cannot explain by itself the recent increase in late winter-early spring fire activity. Additional anthropogenic factors, such as recent changes in

  18. Indonesian fire activity and smoke pollution in 2015 show persistent nonlinear sensitivity to El Niño-induced drought

    NASA Astrophysics Data System (ADS)

    Field, Robert D.; van der Werf, Guido R.; Fanin, Thierry; Fetzer, Eric J.; Fuller, Ryan; Jethva, Hiren; Levy, Robert; Livesey, Nathaniel J.; Luo, Ming; Torres, Omar; Worden, Helen M.

    2016-08-01

    The 2015 fire season and related smoke pollution in Indonesia was more severe than the major 2006 episode, making it the most severe season observed by the NASA Earth Observing System satellites that go back to the early 2000s, namely active fire detections from the Terra and Aqua Moderate Resolution Imaging Spectroradiometers (MODIS), MODIS aerosol optical depth, Terra Measurement of Pollution in the Troposphere (MOPITT) carbon monoxide (CO), Aqua Atmospheric Infrared Sounder (AIRS) CO, Aura Ozone Monitoring Instrument (OMI) aerosol index, and Aura Microwave Limb Sounder (MLS) CO. The MLS CO in the upper troposphere showed a plume of pollution stretching from East Africa to the western Pacific Ocean that persisted for 2 mo. Longer-term records of airport visibility in Sumatra and Kalimantan show that 2015 ranked after 1997 and alongside 1991 and 1994 as among the worst episodes on record. Analysis of yearly dry season rainfall from the Tropical Rainfall Measurement Mission (TRMM) and rain gauges shows that, due to the continued use of fire to clear and prepare land on degraded peat, the Indonesian fire environment continues to have nonlinear sensitivity to dry conditions during prolonged periods with less than 4 mm/d of precipitation, and this sensitivity appears to have increased over Kalimantan. Without significant reforms in land use and the adoption of early warning triggers tied to precipitation forecasts, these intense fire episodes will reoccur during future droughts, usually associated with El Niño events.

  19. Indonesian fire activity and smoke pollution in 2015 show persistent nonlinear sensitivity to El Niño-induced drought.

    PubMed

    Field, Robert D; van der Werf, Guido R; Fanin, Thierry; Fetzer, Eric J; Fuller, Ryan; Jethva, Hiren; Levy, Robert; Livesey, Nathaniel J; Luo, Ming; Torres, Omar; Worden, Helen M

    2016-08-16

    The 2015 fire season and related smoke pollution in Indonesia was more severe than the major 2006 episode, making it the most severe season observed by the NASA Earth Observing System satellites that go back to the early 2000s, namely active fire detections from the Terra and Aqua Moderate Resolution Imaging Spectroradiometers (MODIS), MODIS aerosol optical depth, Terra Measurement of Pollution in the Troposphere (MOPITT) carbon monoxide (CO), Aqua Atmospheric Infrared Sounder (AIRS) CO, Aura Ozone Monitoring Instrument (OMI) aerosol index, and Aura Microwave Limb Sounder (MLS) CO. The MLS CO in the upper troposphere showed a plume of pollution stretching from East Africa to the western Pacific Ocean that persisted for 2 mo. Longer-term records of airport visibility in Sumatra and Kalimantan show that 2015 ranked after 1997 and alongside 1991 and 1994 as among the worst episodes on record. Analysis of yearly dry season rainfall from the Tropical Rainfall Measurement Mission (TRMM) and rain gauges shows that, due to the continued use of fire to clear and prepare land on degraded peat, the Indonesian fire environment continues to have nonlinear sensitivity to dry conditions during prolonged periods with less than 4 mm/d of precipitation, and this sensitivity appears to have increased over Kalimantan. Without significant reforms in land use and the adoption of early warning triggers tied to precipitation forecasts, these intense fire episodes will reoccur during future droughts, usually associated with El Niño events.

  20. Indonesian fire activity and smoke pollution in 2015 show persistent nonlinear sensitivity to El Niño-induced drought

    PubMed Central

    Field, Robert D.; van der Werf, Guido R.; Fanin, Thierry; Fetzer, Eric J.; Fuller, Ryan; Jethva, Hiren; Levy, Robert; Livesey, Nathaniel J.; Luo, Ming; Torres, Omar; Worden, Helen M.

    2016-01-01

    The 2015 fire season and related smoke pollution in Indonesia was more severe than the major 2006 episode, making it the most severe season observed by the NASA Earth Observing System satellites that go back to the early 2000s, namely active fire detections from the Terra and Aqua Moderate Resolution Imaging Spectroradiometers (MODIS), MODIS aerosol optical depth, Terra Measurement of Pollution in the Troposphere (MOPITT) carbon monoxide (CO), Aqua Atmospheric Infrared Sounder (AIRS) CO, Aura Ozone Monitoring Instrument (OMI) aerosol index, and Aura Microwave Limb Sounder (MLS) CO. The MLS CO in the upper troposphere showed a plume of pollution stretching from East Africa to the western Pacific Ocean that persisted for 2 mo. Longer-term records of airport visibility in Sumatra and Kalimantan show that 2015 ranked after 1997 and alongside 1991 and 1994 as among the worst episodes on record. Analysis of yearly dry season rainfall from the Tropical Rainfall Measurement Mission (TRMM) and rain gauges shows that, due to the continued use of fire to clear and prepare land on degraded peat, the Indonesian fire environment continues to have nonlinear sensitivity to dry conditions during prolonged periods with less than 4 mm/d of precipitation, and this sensitivity appears to have increased over Kalimantan. Without significant reforms in land use and the adoption of early warning triggers tied to precipitation forecasts, these intense fire episodes will reoccur during future droughts, usually associated with El Niño events. PMID:27482096

  1. Drought, Fire and Insects in Western US Forests: Observations to Improve Regional Land System Modeling

    NASA Astrophysics Data System (ADS)

    Law, B. E.; Yang, Z.; Berner, L. T.; Hicke, J. A.; Buotte, P.; Hudiburg, T. W.

    2015-12-01

    Drought, fire and insects are major disturbances in the western US, and conditions are expected to get warmer and drier in the future. We combine multi-scale observations and modeling with CLM4.5 to examine the effects of these disturbances on forests in the western US. We modified the Community Land Model, CLM4.5, to improve simulated drought-related mortality in forests, and prediction of insect outbreaks under future climate conditions. We examined differences in plant traits that represent species variation in sensitivity to drought, and redefined plant groupings in PFTs. Plant traits, including sapwood area: leaf area ratio and stemwood density were strongly correlated with water availability during the ecohydrologic year. Our database of co-located observations of traits for 30 tree species was used to produce parameterization of the model by species groupings according to similar traits. Burn area predicted by the new fire model in CLM4.5 compares well with recent years of GFED data, but has a positive bias compared with Landsat-based MTBS. Biomass mortality over recent decades increased, and was captured well by the model in general, but missed mortality trends of some species. Comparisons with AmeriFlux data showed that the model with dynamic tree mortality only (no species trait improvements) overestimated GPP in dry years compared with flux data at semi-arid sites, and underestimated GPP at more mesic sites that experience dry summers. Simulations with both dynamic tree mortality and species trait parameters improved estimates of GPP by 17-22%; differences between predicted and observed NEE were larger. Future projections show higher productivity from increased atmospheric CO2 and warming that somewhat offsets drought and fire effects over the next few decades. Challenges include representation of hydraulic failure in models, and availability of species trait and carbon/water process data in disturbance- and drought-impacted regions.

  2. In-situ Observations of Mid-latitude Forest Fire Plumes Deep in the Stratosphere

    NASA Technical Reports Server (NTRS)

    Jost, Hans-Juerg; Drdla, Katja; Stohl, Andreas; Pfister, Leonhard; Loewenstein, Max; Lopez, Jimena P.; Hudson, Paula K.; Murphy, Daniel M.; Cziczo, Daniel J.; Fromm, Michael

    2004-01-01

    We observed a plume of air highly enriched in carbon monoxide and particles in the stratosphere at altitudes up to 15.8 km. It can be unambiguously attributed to North American forest fires. This plume demonstrates an extratropical direct transport path from the planetary boundary layer several kilometers deep into the stratosphere, which is not fully captured by large-scale atmospheric transport models. This process indicates that the stratospheric ozone layer could be sensitive to changes in forest burning associated with climatic warming.

  3. Movement observation specifies motor programs activated by the action observed objective.

    PubMed

    Lago, Angel; Fernandez-del-Olmo, Miguel

    2011-04-15

    There are human cortical areas that fire both when a person executes an action and when he observes someone performing a similar action. The observer activates a motor program that resembles the observed action. However, it is not known whether the motor program activated via action observation is muscle specific. In this study, using simple pulse transcranial magnetic stimulation (TMS) applied over the primary motor cortex (M1), we investigated whether the Mirror System activates a muscle specific motor program, or codes the observed action in terms of its goal. The results showed that when subjects observed a static effector in front of an object, cortical excitability was enhanced even in muscles not involved in the observed movement, but that are able to achieve the goal of the action. When there was an effector-object interaction the motor program activated via action observation is muscle specific. These results suggest that when subjects observe an object related action there is an activation of a motor program based on the observed action goal, that is transformed into a muscle specific program when the subject shows an effector-object interaction.

  4. Blending forest fire smoke forecasts with observed data can improve their utility for public health applications

    NASA Astrophysics Data System (ADS)

    Yuchi, Weiran; Yao, Jiayun; McLean, Kathleen E.; Stull, Roland; Pavlovic, Radenko; Davignon, Didier; Moran, Michael D.; Henderson, Sarah B.

    2016-11-01

    Fine particulate matter (PM2.5) generated by forest fires has been associated with a wide range of adverse health outcomes, including exacerbation of respiratory diseases and increased risk of mortality. Due to the unpredictable nature of forest fires, it is challenging for public health authorities to reliably evaluate the magnitude and duration of potential exposures before they occur. Smoke forecasting tools are a promising development from the public health perspective, but their widespread adoption is limited by their inherent uncertainties. Observed measurements from air quality monitoring networks and remote sensing platforms are more reliable, but they are inherently retrospective. It would be ideal to reduce the uncertainty in smoke forecasts by integrating any available observations. This study takes spatially resolved PM2.5 estimates from an empirical model that integrates air quality measurements with satellite data, and averages them with PM2.5 predictions from two smoke forecasting systems. Two different indicators of population respiratory health are then used to evaluate whether the blending improved the utility of the smoke forecasts. Among a total of six models, including two single forecasts and four blended forecasts, the blended estimates always performed better than the forecast values alone. Integrating measured observations into smoke forecasts could improve public health preparedness for smoke events, which are becoming more frequent and intense as the climate changes.

  5. Rapid response tools and datasets for post-fire modeling: linking Earth Observations and process-based hydrological models to support post-fire remediation

    NASA Astrophysics Data System (ADS)

    Miller, M. E.; Billmire, M.; Elliot, W. J.; Endsley, K. A.; Robichaud, P. R.

    2015-04-01

    Preparation is key to utilizing Earth Observations and process-based models to support post-wildfire mitigation. Post-fire flooding and erosion can pose a serious threat to life, property and municipal water supplies. Increased runoff and sediment delivery due to the loss of surface cover and fire-induced changes in soil properties are of great concern. Remediation plans and treatments must be developed and implemented before the first major storms in order to be effective. One of the primary sources of information for making remediation decisions is a soil burn severity map derived from Earth Observation data (typically Landsat) that reflects fire induced changes in vegetation and soil properties. Slope, soils, land cover and climate are also important parameters that need to be considered. Spatially-explicit process-based models can account for these parameters, but they are currently under-utilized relative to simpler, lumped models because they are difficult to set up and require spatially-explicit inputs (digital elevation models, soils, and land cover). Our goal is to make process-based models more accessible by preparing spatial inputs before a fire, so that datasets can be rapidly combined with soil burn severity maps and formatted for model use. We are building an online database (http://geodjango.mtri.org/geowepp /) for the continental United States that will allow users to upload soil burn severity maps. The soil burn severity map is combined with land cover and soil datasets to generate the spatial model inputs needed for hydrological modeling of burn scars. Datasets will be created to support hydrological models, post-fire debris flow models and a dry ravel model. Our overall vision for this project is that advanced GIS surface erosion and mass failure prediction tools will be readily available for post-fire analysis using spatial information from a single online site.

  6. Firing Behavior and Network Activity of Single Neurons in Human Epileptic Hypothalamic Hamartoma

    PubMed Central

    Steinmetz, Peter N.; Wait, Scott D.; Lekovic, Gregory P.; Rekate, Harold L.; Kerrigan, John F.

    2013-01-01

    Objective: Human hypothalamic hamartomas (HH) are intrinsically epileptogenic and are associated with treatment-resistant gelastic seizures. The basic cellular mechanisms responsible for seizure onset within HH are unknown. We used intra-operative microwire recordings of single neuron activity to measure the spontaneous firing rate of neurons and the degree of functional connection between neurons within the tumor. Technique: Fourteen patients underwent transventricular endoscopic resection of HH for treatment-resistant epilepsy. Prior to surgical resection, single neuron recordings from bundled microwires (total of nine contacts) were obtained from HH tissue. Spontaneous activity was recorded for two or three 5-min epochs under steady-state general anesthesia. Off-line analysis included cluster analysis of single unit activity and probability analysis of firing relationships between pairs of neurons. Results: Altogether, 222 neurons were identified (mean 6 neurons per recording epoch). Cluster analysis of single neuron firing utilizing a mixture of Gaussians model identified two distinct populations on the basis of firing rate (median firing frequency 0.6 versus 15.0 spikes per second; p < 10−5). Cluster analysis identified three populations determined by levels of burst firing (median burst indices of 0.015, 0.18, and 0.39; p < 10−15). Unbiased analysis of spontaneous single unit behavior showed that 51% of all possible neuron pairs within each recording epoch had a significant level of firing synchrony (p < 10−15). The subgroup of neurons with higher median firing frequencies was more likely to demonstrate synchronous firing (p < 10−7). Conclusion: Hypothalamic hamartoma tissue in vivo contains neurons which fire spontaneously. The activity of single neurons is diverse but distributes into at least two electrophysiological phenoytpes. Functional linkage between single neurons suggests that HH neurons exist within local networks that may

  7. Atmospheric CH4 and CO2 enhancements and biomass burning emission ratios derived from satellite observations of the 2015 Indonesian fire plumes

    NASA Astrophysics Data System (ADS)

    Parker, Robert J.; Boesch, Hartmut; Wooster, Martin J.; Moore, David P.; Webb, Alex J.; Gaveau, David; Murdiyarso, Daniel

    2016-08-01

    The 2015-2016 strong El Niño event has had a dramatic impact on the amount of Indonesian biomass burning, with the El Niño-driven drought further desiccating the already-drier-than-normal landscapes that are the result of decades of peatland draining, widespread deforestation, anthropogenically driven forest degradation and previous large fire events. It is expected that the 2015-2016 Indonesian fires will have emitted globally significant quantities of greenhouse gases (GHGs) to the atmosphere, as did previous El Niño-driven fires in the region. The form which the carbon released from the combustion of the vegetation and peat soils takes has a strong bearing on its atmospheric chemistry and climatological impacts. Typically, burning in tropical forests and especially in peatlands is expected to involve a much higher proportion of smouldering combustion than the more flaming-characterised fires that occur in fine-fuel-dominated environments such as grasslands, consequently producing significantly more CH4 (and CO) per unit of fuel burned. However, currently there have been no aircraft campaigns sampling Indonesian fire plumes, and very few ground-based field campaigns (none during El Niño), so our understanding of the large-scale chemical composition of these extremely significant fire plumes is surprisingly poor compared to, for example, those of southern Africa or the Amazon.Here, for the first time, we use satellite observations of CH4 and CO2 from the Greenhouse gases Observing SATellite (GOSAT) made in large-scale plumes from the 2015 El Niño-driven Indonesian fires to probe aspects of their chemical composition. We demonstrate significant modifications in the concentration of these species in the regional atmosphere around Indonesia, due to the fire emissions.Using CO and fire radiative power (FRP) data from the Copernicus Atmosphere Service, we identify fire-affected GOSAT soundings and show that peaks in fire activity are followed by subsequent large

  8. Advanced fire-resistant forms of activated carbon and methods of adsorbing and separating gases using same

    SciTech Connect

    Xiong, Yongliang; Wang, Yifeng

    2016-04-19

    A method of removing a target gas from a gas stream is disclosed. The method uses advanced, fire-resistant activated carbon compositions having vastly improved fire resistance. Methods for synthesizing the compositions are also provided. The advanced compositions have high gas adsorption capacities and rapid adsorption kinetics (comparable to commercially-available activated carbon), without having any intrinsic fire hazard.

  9. Utilizing GIS Technology to Improve Fire Prevention Activities in an Urban Fire Department.

    PubMed

    Shields, Wendy C; Shields, Timothy M; McDonald, Eileen M; Perry, Elise C; Hanna, Peter; Gielen, Andrea C

    2015-01-01

    The Baltimore City Fire Department (BCFD) has been installing smoke alarms city wide for more than three decades. Though data on each visit are entered into a database, no system existed for using these data for planning or evaluation. The objective of this study is to use Geographic Information System (GIS) technology and existing databases to 1) determine the number of residences in need of a home visit; 2) determine total visits, visits per household, and number of homes entered for eligible households; and 3) demonstrate integration of various data via GIS for use in prevention planning. The tax assessment database was queried to determine the number of eligible (as determined by BCFD policy) residences in need of a visit. Each attempted BCFD home visit was coded to identify, if the BCFD personnel interacted with residents ("pass door") and installed alarms. Home visits were geocoded and compared to the tax assessment database to determine city wide pass door rates. Frequency of visits was run by individual residences to measure efficiency. A total of 206,850 residences met BCFD eligibility for a home visit. In 2007, the BCFD attempted 181,757 home visits and 177,213 were successfully geocoded to 122,118 addresses. A total of 122,118 eligible residences (59%) received a home visit. A total of 35,317 residences (29%) received a repeat visit attempt. The pass door rate was 22% (46,429) of all residences. GIS technology offers a promising means for fire departments to plan and evaluate the fire prevention services they provide.

  10. Measurements in large pool fires with an actively cooled calorimeter

    SciTech Connect

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

    1995-12-31

    The pool fire thermal test described in Safety Series 6 published by the International Atomic Energy Agency (IAEA) or Title 10, Code of Federal Regulations, Part 71 (10CFR71) in the United States is one of the most difficult tests that a container for larger ``Type B`` quantities of nuclear materials must pass. If retests of a container are required, costly redesign and project delays can result. Accurate measurements and modeling of the pool fire environment will ultimately lower container costs by assuring that containers past the pool fire test on the first attempt. Experiments indicate that the object size or surface temperature of the container can play a role in determining local heat fluxes that are beyond the effects predicted from the simple radiative heat transfer laws. An analytical model described by Nicolette and Larson 1990 can be used to understand many of these effects. In this model a gray gas represents soot particles present in the flame structure. Close to the container surface, these soot particles are convectively and radiatively cooled and interact with incident energy from the surrounding fire. This cooler soot cloud effectively prevents some thermal radiation from reaching the container surface, reducing the surface heat flux below the value predicted by a transparent medium model. With some empirical constants, the model suggested by Nicolette and Larson can be used to more accurately simulate the pool fire environment. Properly formulated, the gray gas approaches also fast enough to be used with standard commercial computer codes to analyze shipping containers. To calibrate this type of model, accurate experimental measurements of radiative absorption coefficients, flame temperatures, and other parameters are necessary. A goal of the calorimeter measurements described here is to obtain such parameters so that a fast, useful design tool for large pool fires can be constructed.

  11. A study of marine stratocumulus using lidar and other FIRE aircraft observations

    NASA Technical Reports Server (NTRS)

    Jensen, Jorgen B.; Lenschow, Donald H.

    1990-01-01

    The National Center for Atmospheric Research (NCAR) airborne infrared lidar system (NAILS) used in the 1987 First ISCCP Regional Experiment (FIRE) off the coast of California is a 10.6 microns wavelength carbon dioxide lidar system constructed by Ron Schwiesow and co-workers at NCAR. The lidar is particularly well suited for detailed observations of cloud shapes; i.e., height of cloud top (when flying above cloud and looking down) and cloud base (when flying below cloud and looking up) along the flight path. A brief summary of the lidar design characteristics is given. The lidar height resolution of plus or minus 3 m allows for the distance between the aircraft and cloud edge to be determined with this accuracy; however, the duration of the emitted pulse is approximately 3 microseconds, which corresponds to a 500 m pulse length. Therefore, variations in backscatter intensities within the clouds can normally not be resolved. Hence the main parameter obtainable from the lidar is distance to cloud; in some cases the cloud depth can also be determined. During FIRE the lidar was operational on 7 of the 10 Electra flights, and data were taken when the distance between cloud and aircraft (minimum range) was at least 500 m. The lidar was usually operated at 8 Hz, which at a flight speed of 100 m s(-1) translates into a horizontal resolution of about 12 m. The backscatter as function of time (equivalent to distance) for each laser pulse is stored in digital form on magnetic tape. Currently, three independent variables are available to the investigators on the FIRE Electra data tapes: lidar range to cloud, strength of return (relative power), and pulse width of return, which is related to penetration depth.

  12. Changes in Fire Activity and Geomorphic Processes During the Early Neoglacial in Southern New Mexico

    NASA Astrophysics Data System (ADS)

    Frechette, J. D.; Meyer, G. A.

    2006-12-01

    The Sacramento Mountains contain numerous small alluvial fans produced by low-order tributaries in ponderosa pine dominated mixed-conifer forests. Arroyos up to 12 m deep in the main valleys expose a 9000 year record of geomorphic change within these fans. Identification and dating of fire-related fan deposits allows us to examine the changing importance of fire-related geomorphic processes through time, and assess the role of climate change in modulating wildfire activity. Data from the middle Rio Peñasco valley show that prior to 4500 cal yr BP fans are dominated by poorly sorted facies containing large clasts and abundant charcoal, typical of fire-related debris-flow deposits. After 4500 BP, charcoal is less common and sediments are finer-grained with features indicative of gradual aggradation and cumulic soil development. Although tree-ring fire-scar studies indicate a low-severity surface- fire regime during the 400 yrs prior to Euro-American settlement, we have identified several fire-related debris- flow deposits dating to the late Holocene that indicate high-severity fires. Fire-related deposits, however, account for a much smaller volume of sediment than prior to 4500 BP. Although the early part of the record is less complete, decreased fire-related sedimentation prior to 6000 BP is also suggested. Increased fire-related sedimentation 6000-4500 BP indicates that fire regimes were significantly different during the middle Holocene, when many paleoclimate records from the region indicate a generally warmer climate. Most recently, deep arroyos, which predate recent severe fires, have formed along the main valley. The lack of comparable paleochannels in the stratigraphic record suggests that these arroyos are the unprecedented result of postsettlement land-use changes. The distinct decrease in fire-related sedimentation after 4500 BP corresponds to a shift towards cooler and wetter conditions at a number of sites in the southwestern USA and northern Mexico

  13. Observations of rapid-fire event tremor at Lascar volcano, Chile

    USGS Publications Warehouse

    Asch, Guenter; Wylegalla, K.; Hellweg, M.; Seidl, D.; Rademacher, H.

    1996-01-01

    During the Proyecto de Investigacio??n Sismolo??gica de la Cordillera Occidental (PISCO '94) in the Atacama desert of Northern Chile, a continuously recording broadband seismic station was installed to the NW of the currently active volcano, Lascar. For the month of April, 1994, an additional network of three, short period, three-component stations was deployed around the volcano to help discriminate its seismic signals from other local seismicity. During the deployment, the volcanic activity at Lascar appeared to be limited mainly to the emission of steam and SO2. Tremor from Lascar is a random, ??rapid-fire?? series of events with a wide range of amplitudes and a quasi-fractal structure. The tremor is generated by an ensemble of independent elementary sources clustered in the volcanic edifice. In the short-term, the excitation of the sources fluctuates strongly, while the long-term power spectrum is very stationary.

  14. Optogenetic activation of septal GABAergic afferents entrains neuronal firing in the medial habenula

    PubMed Central

    Choi, Kyuhyun; Lee, Youngin; Lee, Changwoo; Hong, Seokheon; Lee, Soonje; Kang, Shin Jung; Shin, Ki Soon

    2016-01-01

    The medial habenula (MHb) plays an important role in nicotine-related behaviors such as nicotine aversion and withdrawal. The MHb receives GABAergic input from the medial septum/diagonal band of Broca (MS/DB), yet the synaptic mechanism that regulates MHb activity is unclear. GABA (γ -aminobutyric acid) is a major inhibitory neurotransmitter activating both GABAA receptors and GABAB receptors. Depending on intracellular chloride concentration, however, GABAA receptors also function in an excitatory manner. In the absence of various synaptic inputs, we found that MHb neurons displayed spontaneous tonic firing at a rate of about ~4.4 Hz. Optogenetic stimulation of MS/DB inputs to the MHb evoked GABAA receptor-mediated synaptic currents, which produced stimulus-locked neuronal firing. Subsequent delayed yet lasting activation of GABAB receptors attenuated the intrinsic tonic firing. Consequently, septal GABAergic input alone orchestrates both excitatory GABAA and inhibitory GABAB receptors, thereby entraining the firing of MHb neurons. PMID:27703268

  15. Hinode Observes an Active Sun

    NASA Video Gallery

    The X-ray Telescope on the Japanese/NASA mission Hinode has been observing the full sun, nearly continuously, for an extended period. In this movie significant small-scale dynamic events can be obs...

  16. An Overview of Recent Geostationary Fire Monitoring Activities and Applications in the Western Hemisphere

    NASA Astrophysics Data System (ADS)

    McRae, D. J.; Conard, S. G.; Ivanova, G. A.; Sukhinin, A. I.; Hao, W. M.; Koutzenogii, K. P.; Prins, E. M.; Schmidt, C. C.; Feltz, J. M.

    2002-05-01

    Over the past twenty years the international scientific research and environmental monitoring communities have recognized the vital role environmental satellites can play in detecting and monitoring active fires both regionally and around the globe for hazards applications and to better understand the extent and impact of biomass burning on the global environment. Both groups have stressed the importance of utilizing operational satellites to produce routine fire products and to ensure long-term stable records of fire activity for applications such as land-use/land cover change analyses and global climate change research. The current NOAA GOES system provides the unique opportunity to detect fires throughout the Western Hemisphere every half-hour from a series of nearly identical satellites for a period of 15+ years. This presentation will provide an overview of the GOES biomass burning monitoring program at UW-Madison Cooperative Institute for Meteorological Satellite Studies (CIMSS) with an emphasis on recent applications of the new GOES Wildfire Automated Biomass Burning Algorithm (WF_ABBA). For the past 8 years, CIMSS has utilized the GOES-8 imager to monitor biomass burning trends in South America. Since September 2000, CIMSS has been producing half-hourly fire products in real-time for most of the Western Hemisphere. The WF_ABBA half-hourly fire product is providing new insights into diurnal, spatial, seasonal and interannual fire dynamics in North, Central, and South America. In North America these products are utilized to detect and monitor wildfires in northerly and remote locations. In South America the diurnal GOES fire product is being used as an indicator of land-use and land-cover change and carbon dynamics along the borders between Brazil, Peru, and Bolivia. The Navy is assimilating the Wildfire ABBA fire product into the Navy Aerosol Analysis and Prediction System (NAAPS) to analyze and predict aerosol loading and transport as part of the NASA

  17. Calibration of VIIRS F1 Sensor Fire Detection Band Using lunar Observations

    NASA Technical Reports Server (NTRS)

    McIntire, Jeff; Efremova, Boryana; Xiong, Xiaoxiong

    2012-01-01

    Visible Infrared Imager Radiometer Suite (VIIRS) Fight 1 (Fl) sensor includes a fire detection band at roughly 4 microns. This spectral band has two gain states; fire detection occurs in the low gain state above approximately 345 K. The thermal bands normally utilize an on-board blackbody to provide on-orbit calibration. However, as the maximum temperature of this blackbody is 315 K, the low gain state of the 4 micron band cannot be calibrated in the same manner as the rest of the thermal bands. Regular observations of the moon provide an alternative calibration source. The lunar surface temperature has been recently mapped by the DIVINER sensor on the LRO platform. The periodic on-board high gain calibration along with the DIVINER surface temperatures was used to determine the emissivity and solar reflectance of the lunar surface at 4 microns; these factors and the lunar data are then used to fit the low gain calibration coefficients of the 4 micron band. Furthermore, the emissivity of the lunar surface is well known near 8.5 microns due to the Christiansen feature (an emissivity maximum associated with Si-O stretching vibrations) and the solar reflectance is negligible. Thus, the 8.5 micron band is used for relative calibration with the 4 micron band to de-trend any temporal variations. In addition, the remaining thermal bands are analyzed in a similar fashion, with both calculated emissivities and solar reflectances produced.

  18. TES observations of the interannual variability of PAN over Northern Eurasia and the relationship to springtime fires

    NASA Astrophysics Data System (ADS)

    Zhu, Liye; Fischer, Emily V.; Payne, Vivienne H.; Worden, John R.; Jiang, Zhe

    2015-09-01

    Peroxyacetyl nitrate (PAN) plays an important role in atmospheric chemistry through its impact on remote oxidant and nitrogen budgets. PAN is formed rapidly in boreal fire plumes through the oxidation of short-lived volatile organic compounds in the presence of nitrogen oxide radicals. Here we present new satellite observations of PAN from the Tropospheric Emission Spectrometer (TES) over northern Eurasia for April 2006-2010. We observe large interannual variability in TES PAN observations, and we show that fires are one source of this variability using (1) Moderate Resolution Imaging Spectroradiometer Mean Fire Radiative Power observations and (2) Hybrid Single-Particle Lagrangian Integrated Trajectory backward trajectories. We also show that cold springtime temperatures and enhanced vertical mixing in the lower free troposphere over northeastern Eurasia likely played a role in the detection of PAN from TES in April 2006 in this region.

  19. A trend analysis of global fire activity. Is it land use or climate the main driver?

    NASA Astrophysics Data System (ADS)

    Bistinas, Ioannis; Oom, Duarte; Silva, Joao M. N.; Lopez-Saldaña, Gerardo; Pereira, Jose M. C.

    2016-04-01

    We perform a global trend analysis of active fire counts at 0.5o spatial resolution, using 156 months (January 2001 - December 2013) of MODIS Climate Modelling Grid data (TERRA). We use the Contextual Mann-Kendall (CMK) test to assess the statistical significance at cell level and found that 13% of the global land area displays statistically significant active fire count trends, with a slight predominance of negative trends (50.63% of the total significant cells). We perform the same trend analysis with the unexplained variability (residuals) between active fires and the Fire Weather Index (FWI) that is used as a proxy for climate. There is agreement between the main patterns from the trend analysis coming from the residuals and the active fire trends, implying that the main contemporary fire trends are not climate driven. Spatially coherent patches with significant trends were found in all continents (with the obvious exception of Antarctica). The majority of significant trends occur in areas of high fire incidence, and both increasing and decreasing trends appear to be associated with land use change processes. The analysis reveals large negative trends at the Sahel and between Russia and Kazakhstan, whereas a massive and coherent positive trend appears in southeastern Asia. Smaller patches of positive trends appear in southeastern United States and in Mexico, as well as in Brazil and between Argentina and Paraguay, and in Asia in India. There are also negative trends in Brazil, Argentina and in Australia. The study highlights the land use activities as the main driver of these trends, but also the need for data driven analyses and longer time series for future studies in order to gain better knowledge on fire occurrence.

  20. Sentinel-3 Satellite Applications In The Monitoring Of The Active Forest Fires

    NASA Astrophysics Data System (ADS)

    Calle, A.; Gonzalez-Alonso, F.

    2013-12-01

    FRP (Fire Radiative Power) is the magnitude associated to the thermal radiance which explains the ecological effects of active fire; it is the component of the chemical power released from burning vegetation and emitted as radiation during the process of combustion. In this paper, a discussion of the procedures for active fire FRP is presented: The Dozier method, the MODIS (Moderate Resolution Imaging Spectroradiometer) fire detection algorithm and semi-empirical relation-ship based on previous studies of BIRD (Bi-spectral InfraRed Detection) satellite. These procedures, described above, are applied to simulated data by a radiative transfer model, based on Sentinel-3/SLSTR spectral characteristics in order to analyze the impact of atmospheric conditions on FRP estimations.

  1. Fire Effects on Microbial Enzyme Activities in Larch Forests of the Siberian Arctic

    NASA Astrophysics Data System (ADS)

    Ludwig, S.; Alexander, H. D.; Bulygina, E. B.; Mann, P. J.; Natali, S.

    2012-12-01

    Arctic forest ecosystems are warming at an accelerated rate relative to lower latitudes, with global implications for C cycling within these regions. As climate continues to warm and dry, wildfire frequency and severity are predicted to increase, creating a positive feedback to climate warming. Increased fire activity will also influence the microenvironment experienced by soil microbes in disturbed soils. Because soil microbes regulate carbon (C) and nitrogen (N) cycling between terrestrial ecosystems and the atmosphere, it is important to understand microbial response to fires, particularly in the understudied larch forests in the Siberian Arctic. In this project, we created experimental burn plots in a mature larch forest in the Kolyma River watershed of Northeastern Siberia. Plots were burned at several treatments: control (no burn), low, moderate, and severe. After, 1 and 8 d post-fire, we measured soil organic layer depth, soil organic matter (SOM) content, soil moisture, and CO2 flux from the plots. Additionally, we leached soils and measured dissolved organic carbon (DOC), total dissolved nitrogen (TDN), NH4, NO3, soluble reactive phosphorus (SRP), and chromophoric dissolved organic matter (CDOM). Furthermore, we measured extracellular activity of four enzymes involved in soil C and nutrient cycling (leucine aminopeptidase (LAP), β-glucosidase, phosphatase, and phenol oxidase). One day post-fire, LAP activity was similarly low in all treatments, but by 8 d post-fire, LAP activity was lower in burned plots compared to control plots, likely due to increased nitrogen content with increasing burn severity. Phosphatase activity decreased with burn severity 1 d post-fire, but after 8 d, moderate and severe burn plots exhibited increased phosphatase activity. Coupled with trends in LAP activity, this suggests a switch in nutrient limitation from N to phosphorus that is more pronounced with burn severity. β-glucosidase activity similarly decreased with burn

  2. Evaluating Greenhouse Gas Emissions Reporting Systems for Agricultural Waste Burning Using MODIS Active Fires

    NASA Astrophysics Data System (ADS)

    Lin, H.; Jin, Y.; Giglio, L.; Foley, J. A.; Randerson, J. T.

    2010-12-01

    Fires in agricultural ecosystems emit greenhouse gases and aerosols that influence climate on multiple spatial and temporal scales. Annex 1 countries of the United Nations Framework Convention on Climate Change (UNFCCC), many of which ratified the Kyoto Protocol, are required to report emissions of CO2, CH4 and N2O from these fires annually. We evaluated several aspects of this reporting system, including the optimality of the crops targeted by the UNFCCC globally and within Annex 1 countries and the consistency of emissions reporting among countries. We also evaluated the success of the individual countries in capturing interannual variability and long-term trends in agricultural fire activity. We combined global crop maps with Terra and Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) active fire detections. At a global scale, we recommend adding ground nuts, cocoa, cotton and oil palm, and removing potato, oats, pulse other and rye from the UNFCCC list of 14 crops. This leads to an overall increase of 6% of the active fires covered by the reporting system. Optimization led to a different recommended list for Annex 1 countries. Extending emissions reporting to all Annex 1 countries (from the current set of 19 countries) would increase the efficacy of the reporting system from 10% to 20%, and further including several non-Annex 1 countries (Argentina, Brazil, China, India, Indonesia, Thailand, Kazakhstan, Mexico and Nigeria) would capture over 58% of active fires in croplands worldwide. Analyses of interannual trends from the U.S. and Australia showed the importance of both intensity of fire use and crop production in controlling year-to-year variations in agricultural fire emissions. Remote sensing provides an efficient tool for an independent assessment of current UNFCCC emissions reporting system; and, if combined with census data, field experiments and expert opinion, has the potential for improving the robustness of the next generation inventory

  3. IRAS observations of active galaxies

    NASA Technical Reports Server (NTRS)

    Neugebauer, G.; Soifer, B. T.; Rowan-Robinson, M.

    1985-01-01

    The IRAS survey gives an unbiased view of the infrared properties of the active galaxies. Seyfert galaxies occupy much the same area in color-color plots as to normal infrared bright galaxies, but extend the range towards flatter 60 to 25 mm slopes. Statistically the Seyfert 1 galaxies can be distinguished from the Seyfert 2 galaxies, lying predominantly closer to the area with constant slopes between 25 and 200 mm. The infrared measurements of the Seyfert galaxies cannot distinguish between the emission mechanisms in these objects although they agree with the currently popular ideas; they do provide a measure of the total luminosity of the Seyferts. The quasar's position in the color-color diagrams continue the trend of the Seyferts. The quasar 3C48 is shown to be exceptional among the radio loud quasars in that it has a high infrared luminosity which dominates the power output of the quasar and is most likely associated with the underlying host galaxy.

  4. Observations and analysis of organic aerosol evolution in some prescribed fire smoke plumes

    NASA Astrophysics Data System (ADS)

    May, A. A.; Lee, T.; McMeeking, G. R.; Akagi, S.; Sullivan, A. P.; Urbanski, S.; Yokelson, R. J.; Kreidenweis, S. M.

    2015-06-01

    Open biomass burning is a significant source of primary air pollutants such as particulate matter (PM) and non-methane organic gases (NMOG). However, the physical and chemical atmospheric processing of these emissions during transport is poorly understood. Atmospheric transformations of biomass burning emissions have been investigated in environmental chambers, but there have been limited opportunities to investigate these transformations in the atmosphere. In this study, we deployed a suite of real-time instrumentation on a Twin Otter aircraft to sample smoke from prescribed fires in South Carolina, conducting measurements at both the source and downwind to characterize smoke evolution with atmospheric aging. Organic aerosol (OA) within the smoke plumes was quantified using an aerosol mass spectrometer (AMS); refractory black carbon (rBC) was quantified using a single-particle soot photometer, and carbon monoxide (CO) and carbon dioxide (CO2) were measured using a cavity ring-down spectrometer. During the two fires for which we were able to obtain aerosol aging data, normalized excess mixing ratios and "export factors" of conserved species (rBC, CO, CO2) suggested that changes in emissions at the source did not account for most of the differences observed in samples of increasing age. An investigation of AMS mass fragments indicated that the in-plume fractional contribution (fm/z) to OA of the primary fragment (m/z 60) decreased downwind, while the fractional contribution of the secondary fragment (m/z 44) increased. Increases in f44 are typically interpreted as indicating chemical aging of OA. Likewise, we observed an increase in the O : C elemental ratio downwind, which is usually associated with aerosol aging. However, the rapid mixing of these plumes into the background air suggests that these chemical transformations may be attributable to the different volatilities of the compounds that fragment to these m/z in the AMS. The gas-particle partitioning behavior

  5. Observations and analysis of organic aerosol evolution in some prescribed fire smoke plumes

    NASA Astrophysics Data System (ADS)

    May, A. A.; Lee, T.; McMeeking, G. R.; Akagi, S.; Sullivan, A. P.; Urbanski, S.; Yokelson, R. J.; Kreidenweis, S. M.

    2015-01-01

    Open biomass burning is a significant source of primary air pollutants such as particulate matter and non-methane organic gases. However, the physical and chemical atmospheric processing of these emissions during transport is poorly understood. Atmospheric transformations of biomass burning emissions have been investigated in environmental chambers, but there have been limited opportunities to investigate these transformations in the atmosphere. In this study, we deployed a suite of real-time instrumentation on a Twin Otter aircraft to sample smoke from prescribed fires in South Carolina, conducting measurements at both the source and downwind to characterize smoke evolution with atmospheric aging. Organic aerosol (OA) within the smoke plumes was quantified using an Aerosol Mass Spectrometer (AMS), along with refractory black carbon (rBC) using a Single Particle Soot Photometer and carbon monoxide (CO) and carbon dioxide (CO2) using a Cavity Ring-Down Spectrometer. During the two fires for which we were able to obtain aerosol aging data, normalized excess mixing ratios and "export factors" of conserved species (rBC, CO, CO2) were unchanged with increasing sample age. Investigation of AMS mass fragments indicated that the in-plume fractional contribution (fm/z) to OA of the primary fragment (m/z 60) decreased downwind, while the fractional contribution of the secondary fragment (m/z 44) increased. Increases in f44 are typically interpreted as indicating chemical production of secondary OA (SOA). Likewise, we observed an increase in the O : C elemental ratio downwind, which is usually associated with aerosol aging. However, the rapid mixing of these plumes into the background air suggests that these chemical transformations may be attributable to the different volatilities of the compounds that fragment to these m/z in the AMS. The gas-particle partitioning behavior of the bulk OA observed during the study was consistent with the predictions from a parameterization

  6. Tropospheric ozone enhancements during the Indonesian Forest Fire Events in 1994 and in 1997 as revealed by ground-based observations

    NASA Astrophysics Data System (ADS)

    Fujiwara, M.; Kita, K.; Kawakami, S.; Ogawa, T.; Komala, N.; Saraspriya, S.; Suripto, A.

    Pronounced enhancements of total and tropospheric ozone were observed with the Brewer spectrophotometer and ozonesondes at Watukosek (7.5°S, 112.6°E), Indonesia in 1994 and in 1997 when extensive forest fires were reported in Indonesia. The integrated tropospheric ozone increased from 20 DU to 40 DU in October 1994 and to 55 DU in October 1997. On October 13, 1994, most ozone mixing ratios were more than 50 ppbv throughout the troposphere and exceeded 80 ppbv at some altitudes. On October 22, 1997, the concentrations were more than 50 ppbv throughout the troposphere and exceeded 100 ppbv at several altitudes. The coincidences of the ozone enhancements with the forest fires suggest the photochemical production of tropospheric ozone due to its precursors emitted from the fires for both cases. The years of 1994 and 1997 correspond to El Niño events when convective activity becomes low in Indonesia. Thus, in this region, it is likely that pronounced enhancements of tropospheric ozone associated with extensive forest fires due to sparse precipitation may take place with a period of a few years coinciding with El Niño events. This is in a marked contrast to the situation in South America and Africa where large-scale biomass burnings occur every year.

  7. Tropical Tropospheric Ozone and Smoke Interactions: Satellite Observations During the 1997 Indonesian Fires

    NASA Technical Reports Server (NTRS)

    Thompson, A. M.; Witte, J. C.; Herman, J. R.; Hudson, R. D.; Frolov, A. D.; Kochhar, A. K.; Fujiwara, M.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    Biomass burning generates hydrocarbons, nitrogen oxides and carbon monoxide that lead to tropospheric ozone pollution. Other combustion products form soot and various aerosol particles that make up smoke. Since early 1997 smoke and tropospheric ozone have been monitored in real-time from TOMS (Total Ozone Mapping Spectrometer) at toms.gsfc.nasa.gov (smoke aerosol) and metosrv2.umd.edu/-tropo (tropospheric ozone). The striking increase in smoke and tropospheric ozone observed during the 1997 Indonesian fires was the first extreme episode observed. During the August-November period, plumes of excess ozone and smoke coincided at times but were decoupled at other times, a phenomenon followed with trajectories. Thus, trans-boundary evolution of smoke and ozone differed greatly. The second discovery of the 1997 TOMS record was a dynamical interaction of ozone with the strong El Nino Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) that led to a jump in tropospheric ozone in March 1997 over the entire Indian Ocean, well ahead of the intense burning period. A climatology of smoke and tropospheric ozone from a 1980's TOMS instrument shows offsets in the timing of these pollutants - further evidence that factors other than biomass burning exert a strong influence on tropical tropospheric ozone.

  8. Remotely-sensed active fire data for protected area management: eight-year patterns in the Manas National Park, India.

    PubMed

    Takahata, Chihiro; Amin, Rajan; Sarma, Pranjit; Banerjee, Gitanjali; Oliver, William; Fa, John E

    2010-02-01

    The Terai-Duar savanna and grasslands, which once extended along most of the Himalayan foothills, now only remain in a number of protected areas. Within these localities, grassland burning is a major issue, but data on frequency and distribution of fires are limited. Here, we analysed the incidence of active fires, which only occur during the dry season (Nov.-Mar.), within a significant area of Terai grasslands: the Manas National Park (MNP), India. We obtained locations of 781 fires during the 2000-2008 dry seasons, from the Fire Information for Resource Management System (FIRMS) that delivers global MODIS hotspot/fire locations using remote sensing and GIS technologies. Annual number of fires rose significantly from around 20 at the start of the study period to over 90 after 2002, with most (85%) detected between December and January. Over half of the fires occurred in tall grasslands, but fire density was highest in wetland and riverine vegetation, dry at the time. Most burning took place near rivers, roads and the park boundary, suggesting anthropogenic origins. A kernel density map of all recorded fires indicated three heavily burnt areas in the MNP, all within the tall grasslands. Our study demonstrates, despite some technical caveats linked to fire detection technology, which is improving, that remote fire data can be a practical tool in understanding fire concentration and burning temporal patterns in highly vulnerable habitats, useful in guiding management.

  9. Remotely-Sensed Active Fire Data for Protected Area Management: Eight-Year Patterns in the Manas National Park, India

    NASA Astrophysics Data System (ADS)

    Takahata, Chihiro; Amin, Rajan; Sarma, Pranjit; Banerjee, Gitanjali; Oliver, William; Fa, John E.

    2010-02-01

    The Terai-Duar savanna and grasslands, which once extended along most of the Himalayan foothills, now only remain in a number of protected areas. Within these localities, grassland burning is a major issue, but data on frequency and distribution of fires are limited. Here, we analysed the incidence of active fires, which only occur during the dry season (Nov.-Mar.), within a significant area of Terai grasslands: the Manas National Park (MNP), India. We obtained locations of 781 fires during the 2000-2008 dry seasons, from the Fire Information for Resource Management System (FIRMS) that delivers global MODIS hotspot/fire locations using remote sensing and GIS technologies. Annual number of fires rose significantly from around 20 at the start of the study period to over 90 after 2002, with most (85%) detected between December and January. Over half of the fires occurred in tall grasslands, but fire density was highest in wetland and riverine vegetation, dry at the time. Most burning took place near rivers, roads and the park boundary, suggesting anthropogenic origins. A kernel density map of all recorded fires indicated three heavily burnt areas in the MNP, all within the tall grasslands. Our study demonstrates, despite some technical caveats linked to fire detection technology, which is improving, that remote fire data can be a practical tool in understanding fire concentration and burning temporal patterns in highly vulnerable habitats, useful in guiding management.

  10. Impacts of a Fire Smoke Plume on Deep Convective Clouds Observed during DC3

    NASA Astrophysics Data System (ADS)

    Takeishi, A.; Storelvmo, T.; Zagar, M.

    2014-12-01

    While the ability of aerosols to act as cloud condensation nuclei (CCN) and ice nuclei (IN) is well recognized, the effects of changing aerosol number concentrations on convective clouds have only been studied extensively in recent years. As deep convective clouds can produce heavy precipitation and may sometimes bring severe damages, especially in the tropics, we need to understand the changes in the convective systems that could stem from aerosol perturbations. By perturbing convective clouds, it has also been proposed that aerosols can affect large-scale climate. According to the convective invigoration mechanism, an increase in the aerosol concentration could lead to a larger amount of rainfall and higher vertical velocities in convective clouds, due to an increase in the latent heat release aloft. With some of the satellite observations supporting this mechanism, it is necessary to understand how sensitive the model simulations actually are to aerosol perturbations. This study uses the Weather Research and Forecasting (WRF) model as a cloud-resolving model to reproduce deep convective clouds observed during the Deep Convective Clouds and Chemistry (DC3) field campaign. The convective cloud of our interest was observed in northeastern Colorado on June 22nd in 2012, with a plume of forest fire smoke flowing into its core. Compared to other convective cells observed in the same area on different days, our aircraft data analysis shows that the convective cloud in question included more organic aerosols and more CCN. These indicate the influence of the biomass burning. We compare the results from simulations with different microphysics schemes and different cloud or ice number concentrations. These sensitivity tests tell us how different the amount and the pattern of precipitation would have been if the aerosol concentration had been higher or lower on that day. Both the sensitivity to aerosol perturbation and the reproducibility of the storm are shown to highly

  11. Effects of naltrexone on firing activity of rat cortex neurons and its interactions with ethanol.

    PubMed

    Kozhechkin, S N; Mednikova, Yu S; Kolik, L G

    2013-09-01

    Naltrexone dose-dependently decreased neuron firing rate in the rat frontal cortex after intravenous (1-20 mg/kg) and microelectrophoretic administration. Microelectrophoretic applications of naltrexone reduced the excitatory neuronal response of neurons to low doses of ethanol (electroosmotic application) and potentiated depression of firing activity induced by ethanol in high doses. We concluded that opioid peptides take part in generation of spontaneous neuronal activity in the frontal cortex and neuronal excitation caused by ethanol in low doses. Naltrexone acts as a synergist of ethanol in its depressive effect on cortical neurons.

  12. REFINING FIRE EMISSIONS FOR AIR QUALITY MODELING WITH REMOTELY-SENSED FIRE COUNTS: A WILDFIRE CASE STUDY

    EPA Science Inventory

    This paper examines the use of Moderate Resolution Imaging Spectroradiometer (MODIS) observed active fire data (pixel counts) to refine the National Emissions Inventory (NEI) fire emission estimates for major wildfire events. This study was motivated by the extremely limited info...

  13. Measurement of inter- and intra-annual variability of landscape fire activity at a continental scale: the Australian case

    NASA Astrophysics Data System (ADS)

    Williamson, Grant J.; Prior, Lynda D.; Jolly, W. Matt; Cochrane, Mark A.; Murphy, Brett P.; Bowman, David M. J. S.

    2016-03-01

    Climate dynamics at diurnal, seasonal and inter-annual scales shape global fire activity, although difficulties of assembling reliable fire and meteorological data with sufficient spatio-temporal resolution have frustrated quantification of this variability. Using Australia as a case study, we combine data from 4760 meteorological stations with 12 years of satellite-derived active fire detections to determine day and night time fire activity, fire season start and end dates, and inter-annual variability, across 61 objectively defined climate regions in three climate zones (monsoon tropics, arid and temperate). We show that geographic patterns of landscape burning (onset and duration) are related to fire weather, resulting in a latitudinal gradient from the monsoon tropics in winter, through the arid zone in all seasons except winter, and then to the temperate zone in summer and autumn. Peak fire activity precedes maximum lightning activity by several months in all regions, signalling the importance of human ignitions in shaping fire seasons. We determined median daily McArthur forest fire danger index (FFDI50) for days and nights when fires were detected: FFDI50 varied substantially between climate zones, reflecting effects of fire management in the temperate zone, fuel limitation in the arid zone and abundance of flammable grasses in the monsoon tropical zone. We found correlations between the proportion of days when FFDI exceeds FFDI50 and the Southern Oscillation index across the arid zone during spring and summer, and Indian Ocean dipole mode index across south-eastern Australia during summer. Our study demonstrates that Australia has a long fire weather season with high inter-annual variability relative to all other continents, making it difficult to detect long term trends. It also provides a way of establishing robust baselines to track changes to fire seasons, and supports a previous conceptual model highlighting multi-temporal scale effects of climate in

  14. Human and climate impacts on Holocene fire activity recorded in polar and mountain ice cores

    NASA Astrophysics Data System (ADS)

    Kehrwald, Natalie; Zennaro, Piero; Kirchgeorg, Torben; Li, Quanlian; Wang, Ninglian; Power, Mitchell; Zangrando, Roberta; Gabrielli, Paolo; Thompson, Lonnie; Gambaro, Andrea; Barbante, Carlo

    2014-05-01

    Fire is one of the major influences of biogeochemical change on local to hemispheric scales through emitting greenhouse gases, altering atmospheric chemistry, and changing primary productivity. Levoglucosan (1,6-anhydro-β-D-glucopyranose) is a specific molecular that can only be produced by cellulose burning at temperatures > 300°C, comprises a major component of smoke plumes, and can be transported across > 1000 km distances. Levoglucosan is deposited on and archived in glaciers over glacial interglacial cycles resulting in pyrochemical evidence for exploring interactions between fire, climate and human activity. Ice core records provide records of past biomass burning from regions of the world with limited paleofire data including polar and low-latitude, high-altitude regions. Here, we present Holocene fire activity records from the NEEM, Greenland (77° 27'N; 51° 3'W; 2454 masl), EPICA Dome C, Antarctica (75° 06'S; 123° 21'E; 3233 masl), Kilimanjaro, Tanzania (3° 05'S, 21.2° E, 5893 masl) and the Muztagh, China (87.17° E; 36.35° N; 5780 masl ice cores. The NEEM ice core reflects boreal fire activity from both North American and Eurasian sources. Temperature is the dominant control of NEEM levoglucosan flux over decadal to millennial time scales, while droughts influence fire activity over sub-decadal timescales. Our results demonstrate the prominence of Siberian fire sources during intense multiannual droughts. Unlike the NEEM core, which incorporates the largest land masses in the world as potential fire sources, EPICA Dome C is located far from any possible fire source. However, EPICA Dome C levoglucosan concentrations are consistently above detection limits and demonstrate a substantial 1000-fold increase in fire activity beginning approximately 800 years ago. This significant and sustained increase coincides with Maori arrival and dispersal in New Zealand augmented by later European arrival in Australia. The EPICA Dome C levoglucosan profile is

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

    SciTech Connect

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

    2015-02-13

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

  16. Seasonal forecasting of fire over Kalimantan, Indonesia

    NASA Astrophysics Data System (ADS)

    Spessa, A. C.; Field, R. D.; Pappenberger, F.; Langner, A.; Englhart, S.; Weber, U.; Stockdale, T.; Siegert, F.; Kaiser, J. W.; Moore, J.

    2015-03-01

    Large-scale fires occur frequently across Indonesia, particularly in the southern region of Kalimantan and eastern Sumatra. They have considerable impacts on carbon emissions, haze production, biodiversity, health, and economic activities. In this study, we demonstrate that severe fire and haze events in Indonesia can generally be predicted months in advance using predictions of seasonal rainfall from the ECMWF System 4 coupled ocean-atmosphere model. Based on analyses of long, up-to-date series observations on burnt area, rainfall, and tree cover, we demonstrate that fire activity is negatively correlated with rainfall and is positively associated with deforestation in Indonesia. There is a contrast between the southern region of Kalimantan (high fire activity, high tree cover loss, and strong non-linear correlation between observed rainfall and fire) and the central region of Kalimantan (low fire activity, low tree cover loss, and weak, non-linear correlation between observed rainfall and fire). The ECMWF seasonal forecast provides skilled forecasts of burnt and fire-affected area with several months lead time explaining at least 70% of the variance between rainfall and burnt and fire-affected area. Results are strongly influenced by El Niño years which show a consistent positive bias. Overall, our findings point to a high potential for using a more physical-based method for predicting fires with several months lead time in the tropics rather than one based on indexes only. We argue that seasonal precipitation forecasts should be central to Indonesia's evolving fire management policy.

  17. FIRE Data and Information

    Atmospheric Science Data Center

    2015-11-13

    ... a series of field missions which have collected cirrus and marine stratocumulus cloud parameters from aircraft, satellite and ... FIRE I - Cirrus Home Page FIRE I - Marine Stratocumulus Home Page FIRE I - Extended Time Observations ...

  18. Where's the Fire?

    ERIC Educational Resources Information Center

    Needham, Dorothy

    1977-01-01

    National Fire Protection Week is a perfect time for launching a fire safety learning center. The activities described here are intended to help children recognize fire hazards in their homes, play areas and public buildings; learn how to act intelligently in fire emergencies; be able to share their knowledge of fire safety with others and…

  19. Functional activity of soil microbial communities in post-fire pine stands of Tolyatti, Samara oblast

    NASA Astrophysics Data System (ADS)

    Maksimova, E. Yu.; Kudinova, A. G.; Abakumov, E. V.

    2017-02-01

    The state of microbial communities in gray-humus soils (Eutric Fluvic Arenosols (Ochric)) of pine stands in the city of Tolyatti after forest fires of 2010 is analyzed. It is shown that fires exert negative effects on the structure and metabolic activity of microbial communities in the postpyrogenic soils. The content of the carbon of microbial biomass and the intensity of microbial respiration in the upper organic horizons of the post-fire plots decrease by 6.5 and 3.4 times, respectively, in comparison with those in the soils of background plots. However, the fire has not affected the studied microbiological parameters of the soils at the depths of more than 10 cm. The maximum content of the carbon of microbial biomass carbon and the maximum intensity of microbial respiration have been found in the subsurface AY2 and AC horizons two-three years the fire. An increase in the microbial metabolic quotient (the ratio of soil respiration to microbial biomass) attests to the disturbance of the ecophysiological state of soil microbial communities after the pyrogenic impact.

  20. Predicting fire activity in the US over the next 50 years using new IPCC climate projections

    NASA Astrophysics Data System (ADS)

    Wang, D.; Morton, D. C.; Collatz, G. J.

    2012-12-01

    Fire is an integral part of the Earth system with both direct and indirect effects on terrestrial ecosystems, the atmosphere, and human societies (Bowman et al. 2009). Climate conditions regulate fire activities through a variety of ways, e.g., influencing the conditions for ignition and fire spread, changing vegetation growth and decay and thus the accumulation of fuels for combustion (Arora and Boer 2005). Our recent study disclosed the burned area (BA) in US is strongly correlated with potential evaporation (PE), a measurement of climatic dryness derived from National Centers for Environmental Prediction (NCEP) North American Regional Reanalysis (NARR) climate data (Morton et al. 2012). The correlation varies spatially and temporally. With regard to fire of peak fire seasons, Northwestern US, Great Plains and Alaska have the strongest BA/PE relationship. Using the recently released the Global Fire Emissions Database (GFED) Version 3 (van der Werf et al. 2010), we showed increasing BA in the last decade in most of NCA regions. Longer time series of Monitoring Trends in Burn Severity (MTBS) (Eidenshink et al. 2007) data showed the increasing trends occurred in all NCA regions from 1984 to 2010. This relationship between BA and PE provides us the basis to predict the future fire activities in the projected climate conditions. In this study, we build spatially explicit predictors using the historic PE/BA relationship. PE from 2011 to 2060 is calculated from the Coupled Model Intercomparison Project Phase 5 (CMIP5) data and the historic PE/BA relationship is then used to estimate BA. This study examines the spatial pattern and temporal dynamics of the future US fires driven by new climate predictions for the next 50 years. Reference: Arora, V.K., & Boer, G.J. (2005). Fire as an interactive component of dynamic vegetation models. Journal of Geophysical Research-Biogeosciences, 110 Bowman, D.M.J.S., Balch, J.K., Artaxo, P., Bond, W.J., Carlson, J.M., Cochrane, M.A., D

  1. Report on observational activity in (summer) 2015

    NASA Astrophysics Data System (ADS)

    Zejda, M.

    2016-03-01

    A short report on the author's observational activity in 2015 and the last 20 years is given. In total this means almost 900 nights, about a half million of CCD frames and thousands of photometric measurements.

  2. Observing shadow motions: resonant activity within the observer's motor system?

    PubMed

    Alaerts, Kaat; Van Aggelpoel, Tinne; Swinnen, Stephan P; Wenderoth, Nicole

    2009-09-25

    Several studies have demonstrated that the human motor cortex is activated by the mere observation of actions performed by others. In the present study, we explored whether the perception of 'impoverished motion stimuli', such as shadow animations, is sufficient to activate motor areas. To do so, transcranial magnetic stimulation (TMS) was applied over the hand area of the primary motor cortex (M1) while subjects observed shadow animations depicting finger motions. Data showed that resonant motor responses in M1 were only found when a biological effector was recognized from the observed shadow animation. Interestingly, M1 responses were similar for observing shadow or real motions. Therefore, the loss of 'pictorial' movement features in a shadow animation appeared to have no effect on motor resonance in M1. In summary, these findings suggest that the 'recognition' of biological motion from sparse visual input is both necessary and sufficient to recruit motor areas. This supports the hypothesis that the motor system is involved in recognizing the actions performed by others.

  3. Bayesian active learning of neural firing rate maps with transformed gaussian process priors.

    PubMed

    Park, Mijung; Weller, J Patrick; Horwitz, Gregory D; Pillow, Jonathan W

    2014-08-01

    A firing rate map, also known as a tuning curve, describes the nonlinear relationship between a neuron's spike rate and a low-dimensional stimulus (e.g., orientation, head direction, contrast, color). Here we investigate Bayesian active learning methods for estimating firing rate maps in closed-loop neurophysiology experiments. These methods can accelerate the characterization of such maps through the intelligent, adaptive selection of stimuli. Specifically, we explore the manner in which the prior and utility function used in Bayesian active learning affect stimulus selection and performance. Our approach relies on a flexible model that involves a nonlinearly transformed gaussian process (GP) prior over maps and conditionally Poisson spiking. We show that infomax learning, which selects stimuli to maximize the information gain about the firing rate map, exhibits strong dependence on the seemingly innocuous choice of nonlinear transformation function. We derive an alternate utility function that selects stimuli to minimize the average posterior variance of the firing rate map and analyze the surprising relationship between prior parameterization, stimulus selection, and active learning performance in GP-Poisson models. We apply these methods to color tuning measurements of neurons in macaque primary visual cortex.

  4. [Electrical activities of bursting-firing neurons in epileptic network reestablishment of rat hippocampus].

    PubMed

    Wang, Wen-Ting; Qin, Xing-Kui; Yin, Shi-Jin; Han, Dan

    2003-12-25

    ipsilateral or contralateral anterior dorsal HPC were elicited by the ATPDH. The results obtained suggest that bursting-firing of single BFNs is produced by the ATPDH in the anterior dorsal HPC along the longitudinal axis of the ipsilateral HPC or across the hemisphere to the opposite HPC. Rhythmic activities of the BFN may be implicated in the epileptic network reestablishment of the HPC. On the other hand, synaptic modulation of the BFN temporal series might be responsible for pathophysiological information transmission in the HPC-epileptic network.

  5. High pre-industrial and modern Tibetan Plateau fire activity

    NASA Astrophysics Data System (ADS)

    Kehrwald, N. M.; Li, Q.; Wang, N.; Zennaro, P.; Zangrando, R.; Barbante, C.

    2013-12-01

    The South Asian brown cloud created from a mix of biomass burning and fossil fuel aerosols is warming the atmosphere between 5000 to 7000 meters above sea level (m asl) along the southern slope of the Himalaya. The extent to which this atmospheric brown cloud is transported up and over the 7000 to 8000 m asl ridge of the Himalaya and northward across the Tibetan Plateau is unknown. Intense Eastern Asian industry and associated coal burning may also export fossil fuel burning products to the Tibetan Plateau. In addition, local cooking, agricultural and natural fires emit combustion products that alter atmospheric chemistry and are deposited on glacier surfaces. It is essential to differentiate between the effects of fossil fuel and biomass burning across the Tibetan Plateau to determine if combustion products affect glacier surfaces and, by extension, glacier volume. The specific biomarker levoglucosan can only be produced by biomass burning at temperatures of 300°C or higher and is trapped and preserved in glaciers across the globe. This specificity may allow the possibility of differentiating between fossil fuel and biomass burning contributions when comparing levoglucosan concentrations with more general ice core combustion proxies such as black carbon. Here, we present a biomass burning record from the entire 164 m Muztag ice core (36.35°N; 87.17°E; 5780 m asl) and from a southwest to northeast transect of snow pits across the Tibetan Plateau. Multiple total organic carbon and dissolved organic carbon surface samples demonstrate organic carbon concentrations at or near detection limits. However, these samples have high levoglucosan concentrations suggesting that the biomass burning recorded in these sites may be from a regional rather than local source. The Tibetan Plateau levoglucosan concentrations are surprisingly substantially greater than Kilimanjaro levoglucosan concentrations, where Kilimanjaro is located in a relatively similar low-latitude high

  6. Seven hundred years of human-driven and climate-influenced fire activity in a British Columbia coastal temperate rainforest

    PubMed Central

    Gavin, Daniel G.; Starzomski, Brian M.

    2016-01-01

    While wildland fire is globally most common at the savannah-grassland ecotone, there is little evidence of fire in coastal temperate rainforests. We reconstructed fire activity with a ca 700-year fire history derived from fire scars and stand establishment from 30 sites in a very wet (up to 4000 mm annual precipitation) temperate rainforest in coastal British Columbia, Canada. Drought and warmer temperatures in the year prior were positively associated with fire events though there was little coherence of climate indices on the years of fires. At the decadal scale, fires were more likely to occur after positive El Niño-Southern Oscillation and Pacific Decadal Oscillation phases and exhibited 30-year periods of synchrony with the negative phase of the Arctic Oscillation. Fire frequency was significantly inversely correlated with the distance from former Indigenous habitation sites and fires ceased following cultural disorganization caused by disease and other European impacts in the late nineteenth century. Indigenous people were likely to have been the primary ignition source in this and many coastal temperate rainforest settings. These data are directly relevant to contemporary forest management and discredit the myth of coastal temperate rainforests as pristine landscapes. PMID:27853581

  7. Coastal Change Processes Project data report for oceanographic observations near Fire Island, New York, February through May 2014

    USGS Publications Warehouse

    Armstrong, Brandy N.; Warner, John C.; List, Jeffrey H.; Martini, Marinna A.; Montgomery, Ellyn T.; Traykovski, Peter A.; Voulgaris, George

    2015-01-01

    An oceanographic field study during February through May 2014 investigated processes that control the sediment-transport dynamics along the western part of Fire Island, New York. This report describes the project background, field program, instrumentation configuration, and locations of the sensors deployed. The data collected, including meteorological observations, are presented as time-series plots for data visualization. Additionally, individual links to the database containing digital data files are available as part of this report.

  8. Coastal Change Processes Project data report for observations near Fire Island, New York, January to April 2012

    USGS Publications Warehouse

    Armstrong, Brandy N.; Warner, John C.; List, Jeffrey H.; Martini, Marinna A.; Montgomery, Ellyn T.; Voulgaris, George; Traykovski, Peter A.

    2015-01-01

    An oceanographic field study during January through April 2012 investigated processes that control the sediment-transport dynamics near Fire Island, New York. This report describes the project background, field program, instrumentation configuration, and locations of the sensors deploymed. The data collected and supporting meteorological observations are presented as time series plots for data visualization. Additionally, individual, links to the database containing digital data files are available as part of this report.

  9. Support for Astronaut's View of Mexican/ Central American Fires and on-Line Earth Observations Training Manual

    NASA Technical Reports Server (NTRS)

    Kaminski, Charles F., Jr.

    1999-01-01

    A small project to compile remote sensing and in-site data to review the processes leading to the May 1998 Mexican/Central American fires was undertaken. A web page based on this project was assembled. The second project initiated involved an interactive and on-line program that will replace the paper version of the Earth Observations Preflight Training Manual. Technical support was provided to Prof. Marvin Glasser as needed.

  10. Changes on permafrost and active layer characteristics after the tundra fire in summer 2002 in Seward Peninsula, Alaska

    NASA Astrophysics Data System (ADS)

    Sawada, Y.; Harada, K.; Fukuda, M.; Narita, K.

    2006-12-01

    Thermal, water and electrical conditions of permafrost after the tundra fire occurred in summer 2002 were studied in Seward Peninsula, southwest Alaska, in order to evaluate the effect of tundra fire on the arctic permafrost terrains. Field observations were made in summer 2005 and 2006. Four sites were established where the slope direction and surface disturbance condition are different; south- or north-facing, and burned or unburned. At each site ground temperature, water content, thermal conductivity and EC were measured by pit survey, and the seasonal thawed depth measurements were also conducted by using the steel rod from the ground surface. Transient electromagnetic soundings for deeper part and 1D and 2D DC resistivity soundings for shallow part were carried out in the four sites. We compared these field data among the four sites, highlighting in significant differences between burned and unburned sites. Burned sites have deeper thawing depths, and it may correspond with the thin organic soil in the burned sites. Due to the removal of litter and organic soil by the fire, thermal and hydrological regimes of active layer have drastically changed in the burned sites.

  11. Beyond blow-up in excitatory integrate and fire neuronal networks: Refractory period and spontaneous activity.

    PubMed

    Cáceres, María J; Perthame, Benoît

    2014-06-07

    The Network Noisy Leaky Integrate and Fire equation is among the simplest model allowing for a self-consistent description of neural networks and gives a rule to determine the probability to find a neuron at the potential v. However, its mathematical structure is still poorly understood and, concerning its solutions, very few results are available. In the midst of them, a recent result shows blow-up in finite time for fully excitatory networks. The intuitive explanation is that each firing neuron induces a discharge of the others; thus increases the activity and consequently the discharge rate of the full network. In order to better understand the details of the phenomena and show that the equation is more complex and fruitful than expected, we analyze further the model. We extend the finite time blow-up result to the case when neurons, after firing, enter a refractory state for a given period of time. We also show that spontaneous activity may occur when, additionally, randomness is included on the firing potential VF in regimes where blow-up occurs for a fixed value of VF.

  12. The influence of lightning activity and anthropogenic factors on large-scale characteristics of natural fires

    NASA Astrophysics Data System (ADS)

    Eliseev, A. V.; Mokhov, I. I.; Chernokulsky, A. V.

    2017-01-01

    A module for simulating of natural fires (NFs) in the climate model of the A.M. Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences (IAP RAS CM), is extended with respect to the influence of lightning activity and population density on the ignition frequency and fire suppression. The IAP RAS CM is used to perform numerical experiments in accordance with the conditions of the project that intercompares climate models, CMIP5 (Coupled Models Intercomparison Project, phase 5). The frequency of lightning flashes was assigned in accordance with the LIS/OTD satellite data. In the calculations performed, anthropogenic ignitions play an important role in NF occurrences, except for regions at subpolar latitudes and, to a lesser degree, tropical and subtropical regions. Taking into account the dependence of fire frequency on lightning activity and population density intensifies the influence of characteristics of natural fires on the climate changes in tropics and subtropics as compared to the version of the IAP RAS CM that does not take the influence of ignition sources on the large-scale characteristics of NFs into consideration.

  13. Effects of serotonin (5-hydroxytryptamine, 5-HT) reuptake inhibition plus 5-HT(2A) receptor antagonism on the firing activity of norepinephrine neurons.

    PubMed

    Szabo, Steven T; Blier, Pierre

    2002-09-01

    YM992 [(S)-2-[[(7-fluoro-4-indanyl)oxy]methyl]morpholine monohydrochloride] is a selective serotonin (5-hydroxytryptamine; 5-HT) reuptake inhibitor (SSRI) and a potent 5-HT(2A) antagonist. The aim of the present study was to assess, using in vivo extracellular unitary recordings, the effect of acute and sustained administration of YM992 (40 mg kg(-1) day(-1) s.c., using osmotic minipumps) on the spontaneous firing activity of locus coeruleus (LC) norepinephrine (NE) neurons. Acute intravenous injection of YM992 (4 mg kg(-1)) significantly decreased NE neuron firing activity by 29% and blocked the inhibitory effect of a subsequent injection of the 5-HT(2) agonist DOI [1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane hydrochloride]. A 2-day treatment with YM992 decreased the firing rate of NE neurons by 66%, whereas a partial recovery was observed after a 7-day treatment and a complete one after a 21-day treatment. Following the injection of the alpha(2)-adrenoceptor antagonist idazoxan (1 mg kg(-1) i.v.), NE neuron firing was equalized in controls and 2-day YM992-treated rats. This put into evidence an increased degree of activation of alpha(2)-adrenergic autoreceptors in the treated rats. The suppressant effect of the alpha(2)-adrenoceptor agonist clonidine was significantly decreased in long-term YM992-treated rats. The recovery of LC firing activity after long-term YM992 administration could thus be explained by a decreased sensitivity of alpha(2)-adrenergic autoreceptors. Sustained SSRI administration leads to a gradual reduction of the firing activity of NE neurons during long-term administration, whereas YM992 produced opposite effects. The exact basis for the increased synaptic availability of NE by YM992 remains to be elucidated. This NE activity, resulting from 5-HT reuptake inhibition plus 5-HT(2A) receptor antagonism, might confer additional benefits in affective and anxiety disorders.

  14. Using SEVIRI fire observations to drive smoke plumes in the CMAQ air quality model: a case study over Antalya in 2008

    NASA Astrophysics Data System (ADS)

    Baldassarre, G.; Pozzoli, L.; Schmidt, C. C.; Unal, A.; Kindap, T.; Menzel, W. P.; Whitburn, S.; Coheur, P.-F.; Kavgaci, A.; Kaiser, J. W.

    2015-07-01

    Among the atmospheric emission sources, wildfires are episodic events characterized by large spatial and temporal variability. Therefore, accurate information on gaseous and aerosol emissions from fires for specific regions and seasons is critical for air quality forecasts. The Spinning Enhanced Visible and Infrared Imager (SEVIRI) in geostationary orbit provides fire observations over Africa and the Mediterranean with a temporal resolution of 15 min. It thus resolves the complete fire life cycle and captures the fires' peak intensities, which is not possible in Moderate Resolution Imaging Spectroradiometer (MODIS) fire emission inventories like the Global Fire Assimilation System (GFAS). We evaluate two different operational fire radiative power (FRP) products derived from SEVIRI, by studying a large forest fire in Antalya, Turkey, in July-August 2008. The EUMETSAT Land Surface Analysis Satellite Applications Facility (LSA SAF) has higher FRP values during the fire episode than the Wildfire Automated Biomass Burning Algorithm (WF_ABBA). It is also in better agreement with the co-located, gridded MODIS FRP. Both products miss small fires that frequently occur in the region and are detected by MODIS. Emissions are derived from the FRP products. They are used along-side GFAS emissions in smoke plume simulations with the Weather Research and Forecasting (WRF) model and the Community Multiscale Air Quality (CMAQ) model. In comparisons with MODIS aerosol optical thickness (AOT) and Infrared Atmospheric Sounding Interferometer (IASI), CO and NH3 observations show that including the diurnal variability of fire emissions improves the spatial distribution and peak concentrations of the simulated smoke plumes associated with this large fire. They also show a large discrepancy between the currently available operational FRP products, with the LSA SAF being the most appropriate.

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  16. Impacts of tundra fire on active layer condition and estimation of true resistivity value of soil in Seward Peninsula, Alaska

    NASA Astrophysics Data System (ADS)

    Harada, K.; Sawada, Y.; Narita, K.; Fukuda, M.

    2007-12-01

    In Seward Peninsula, southwest Alaska, large tundra fires were occurred in 1997 and 2002, and a discontinuous permafrost area burned widely near the Kougarok River. After fires, a vegetation condition was destroyed and a ground surface thermal condition was changed. Then, field observations were conducted at burned and unburned sites in summer 2005, 2006 and 2007, in order to clarify impacts of the tundra fire on thermal and water conditions of active layer. From pit surveys, ground temperatures at burned sites showed 4-5 °C higher values than those at unburned sites. Soil water contents at burned sites showed relative high values in 2005, but low in 2006. Active layer thicknesses were significantly different between burned and unburned sites, about 60cm and 40cm, respectively. There is no significant increasing of the thickness between 2005 and 2006, however, the thickness in 2007 at north-facing sites increased to 80cm at the burned site and 50cm at the unburned site, respectively. Apparent electrical resistivity values up to 1m deep were obtained from electrical soundings in 2006, and values at burned sites were lower than those at unburned sites due to the thick active layer whose resistivity value is relatively low. As an apparent resistivity value is generally produced from the combination of a true resistivity value and a thickness of a layer, a simple calculation was carried out in order to estimate a true resistivity value of unfrozen mineral soil in the active layer. The calculated results showed that the true resistivity at burned sites was higher than that at unburned sites, which was seemed to correspond to a relative low water condition. This result is in agreement with the measured result of water content in 2006. Using this method, the apparent resistivity may show a soil water condition.

  17. Smoke Dispersion Modeling Over Complex Terrain Using High-Resolution Meteorological Data and Satellite Observations: The FireHub Platform

    NASA Technical Reports Server (NTRS)

    Solomos, S.; Amiridis, V.; Zanis, P.; Gerasopoulos, E.; Sofiou, F. I.; Herekakis, T.; Brioude, J.; Stohl, A.; Kahn, R. A.; Kontoes, C.

    2015-01-01

    A total number of 20,212 fire hot spots were recorded by the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite instrument over Greece during the period 2002e2013. The Fire Radiative Power (FRP) of these events ranged from 10 up to 6000 MW at 1 km resolution, and many of these fire episodes resulted in long-range transport of smoke over distances up to several hundred kilometers. Three different smoke episodes over Greece are analyzed here using real time hot-spot observations from the Spinning Enhanced Visible and Infrared Imager (SEVIRI) satellite instrument as well as from MODIS hot-spots. Simulations of smoke dispersion are performed with the FLEXPART-WRF model and particulate matter emissions are calculated directly from the observed FRP. The modeled smoke plumes are compared with smoke stereo-heights from the Multiangle Imaging Spectroradiometer (MISR) instrument and the sensitivities to atmospheric and modeling parameters are examined. Driving the simulations with high resolution meteorology (4 4 km) and using geostationary satellite data to identify the hot spots allows the description of local scale features that govern smoke dispersion. The long-range transport of smoke is found to be favored over the complex coastline environment of Greece due to the abrupt changes between land and marine planetary boundary layers (PBL) and the decoupling of smoke layers from the surface.

  18. Smoke dispersion modeling over complex terrain using high resolution meteorological data and satellite observations - The FireHub platform

    NASA Astrophysics Data System (ADS)

    Solomos, S.; Amiridis, V.; Zanis, P.; Gerasopoulos, E.; Sofiou, F. I.; Herekakis, T.; Brioude, J.; Stohl, A.; Kahn, R. A.; Kontoes, C.

    2015-10-01

    A total number of 20,212 fire hot spots were recorded by the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite instrument over Greece during the period 2002-2013. The Fire Radiative Power (FRP) of these events ranged from 10 up to 6000 MW at 1 km resolution, and many of these fire episodes resulted in long-range transport of smoke over distances up to several hundred kilometers. Three different smoke episodes over Greece are analyzed here using real time hot-spot observations from the Spinning Enhanced Visible and Infrared Imager (SEVIRI) satellite instrument as well as from MODIS hot-spots. Simulations of smoke dispersion are performed with the FLEXPART-WRF model and particulate matter emissions are calculated directly from the observed FRP. The modeled smoke plumes are compared with smoke stereo-heights from the Multiangle Imaging Spectroradiometer (MISR) instrument and the sensitivities to atmospheric and modeling parameters are examined. Driving the simulations with high resolution meteorology (4 × 4 km) and using geostationary satellite data to identify the hot spots allows the description of local scale features that govern smoke dispersion. The long-range transport of smoke is found to be favored over the complex coastline environment of Greece due to the abrupt changes between land and marine planetary boundary layers (PBL) and the decoupling of smoke layers from the surface.

  19. Design of an actively cooled plate calorimeter for the investigation of pool fire heat fluxes

    SciTech Connect

    Koski, J. A.; Keltner, N. R.; Nicolette, V. F.; Wix, S. D.

    1992-01-01

    For final qualification of shipping containers for transport of hazardous materials, thermal testing in accordance with regulations such as 10CFR71 must be completed. Such tests typically consist of 30 minute exposures with the container fully engulfed in flames from a large, open pool of JP4 jet engine fuel. Despite careful engineering analyses of the container, testing often reveals design problems that must be solved by modification and expensive retesting of the container. One source of this problem is the wide variation in surface heat flux to the container that occurs in pool fires. Average heat fluxes of 50 to 60 kW/m{sup 2} are typical and close the values implied by the radiation model in 10CFR71, but peak fluxes up to 150 kW/m{sup 2} are routinely observed in fires. Heat fluxes in pool fires have been shown to be a function of surface temperature of the container, height above the pool, surface orientation, wind, and other variables. If local variations in the surface heat flux to the container could be better predicted, design analyses would become more accurate, and fewer problems will be uncovered during testing. The objective of the calorimeter design described in this paper is to measure accurately pool fire heat fluxes under controlled conditions, and to provide data for calibration of improved analytical models of local flame-surface interactions.

  20. Electrophysiological characterization of Grueneberg ganglion olfactory neurons: spontaneous firing, sodium conductance, and hyperpolarization-activated currents.

    PubMed

    Liu, Cambrian Y; Xiao, Cheng; Fraser, Scott E; Lester, Henry A; Koos, David S

    2012-09-01

    Mammals rely on their acute olfactory sense for their survival. The most anterior olfactory subsystem in the nose, the Grueneberg ganglion (GG), plays a role in detecting alarm pheromone, cold, and urinary compounds. GG neurons respond homogeneously to these stimuli with increases in intracellular [Ca(2+)] or transcription of immediate-early genes. In this electrophysiological study, we used patch-clamp techniques to characterize the membrane properties of GG neurons. Our results offer evidence of functional heterogeneity in the GG. GG neurons fire spontaneously and independently in several stable patterns, including phasic and repetitive single-spike modes of discharge. Whole cell recordings demonstrated two distinct voltage-gated fast-inactivating Na(+) currents with different steady-state voltage dependencies and different sensitivities to tetrodotoxin. Hodgkin-Huxley simulations showed that these Na(+) currents confer dual mechanisms of action potential generation and contribute to different firing patterns. Additionally, GG neurons exhibited hyperpolarization-activated inward currents that modulated spontaneous firing in vitro. Thus, in GG neurons, the heterogeneity of firing patterns is linked to the unusual repertoire of ionic currents. The membrane properties described here will aid the interpretation of chemosensory function in the GG.

  1. The Built Environment Predicts Observed Physical Activity

    PubMed Central

    Kelly, Cheryl; Wilson, Jeffrey S.; Schootman, Mario; Clennin, Morgan; Baker, Elizabeth A.; Miller, Douglas K.

    2014-01-01

    Background: In order to improve our understanding of the relationship between the built environment and physical activity, it is important to identify associations between specific geographic characteristics and physical activity behaviors. Purpose: Examine relationships between observed physical activity behavior and measures of the built environment collected on 291 street segments in Indianapolis and St. Louis. Methods: Street segments were selected using a stratified geographic sampling design to ensure representation of neighborhoods with different land use and socioeconomic characteristics. Characteristics of the built environment on-street segments were audited using two methods: in-person field audits and audits based on interpretation of Google Street View imagery with each method blinded to results from the other. Segments were dichotomized as having a particular characteristic (e.g., sidewalk present or not) based on the two auditing methods separately. Counts of individuals engaged in different forms of physical activity on each segment were assessed using direct observation. Non-parametric statistics were used to compare counts of physically active individuals on each segment with built environment characteristic. Results: Counts of individuals engaged in physical activity were significantly higher on segments with mixed land use or all non-residential land use, and on segments with pedestrian infrastructure (e.g., crosswalks and sidewalks) and public transit. Conclusion: Several micro-level built environment characteristics were associated with physical activity. These data provide support for theories that suggest changing the built environment and related policies may encourage more physical activity. PMID:24904916

  2. Injection of mineral dust into the free troposphere during fire events observed with polarization lidar at Limassol, Cyprus

    NASA Astrophysics Data System (ADS)

    Nisantzi, A.; Mamouri, R. E.; Ansmann, A.; Hadjimitsis, D.

    2014-11-01

    Four-year observations (2010-2014) with EARLINET polarization lidar and AERONET sun/sky photometer at Limassol (34.7° N, 33° E), Cyprus, were used to study the soil dust content in lofted fire smoke plumes advected from Turkey. This first systematic attempt to characterize less than 3-day-old smoke plumes in terms of particle linear depolarization ratio (PDR), measured with lidar, contributes to the more general effort to properly describe the life cycle of free-tropospheric smoke-dust mixtures from the emission event to phases of long-range transport (> 4 days after emission). We found significant PDR differences with values from 9 to 18% in lofted aerosol layers when Turkish fires contributed to the aerosol burden and of 3-13 % when Turkish fires were absent. High Ångström exponents of 1.4-2.2 during all these events with lofted smoke layers, occurring between 1 and 3 km height, suggest the absence of a pronounced particle coarse mode. When plotted vs. travel time (spatial distance between Limassol and last fire area), PDR decreased strongly from initial values around 16-18% (1 day travel) to 4-8% after 4 days of travel caused by deposition processes. This behavior was found to be in close agreement with findings described in the literature. Computation of particle extinction coefficient and mass concentrations, derived from the lidar observations, separately for fine-mode dust, coarse-mode dust, and non-dust aerosol components show extinction-related dust fractions on the order of 10% (for PDR =4%, travel times > 4 days) and 50% (PDR =15%, 1 day travel time) and respective mass-related dust fractions of 25% (PDR =4%) to 80% (PDR =15%). Biomass burning should therefore be considered as another source of free tropospheric soil dust.

  3. Vegetation changes caused by fire in the Florida flatwoods as observed by remote sensing

    NASA Technical Reports Server (NTRS)

    Mealor, W. T., Jr.; Prunty, M. C., Jr.

    1969-01-01

    The nature of the flatwoods and the role that ground fires have played in maintaining them are discussed. Emphasis is placed on the areal and temporal extent of burns as recorded uniformly by remote sensors. Thermal infrared, color infrared, and Ektachrome imagery were obtained from sensors flown by a NASA aircraft at 15,000 feet over a test site in Osceola County, Florida, in March 1968. The overall pattern of burning can be sequenced and mapped uniformly from the imagery. By comparing the various imagery, areal and temporal extent of burned areas can be determined. It was concluded that remote sensed imagery provides more accurate and areally comprehensive media for assessing the impact of ground fires on the landscape of the flatwoods region than are available from any other data source.

  4. Earth observation archive activities at DRA Farnborough

    NASA Technical Reports Server (NTRS)

    Palmer, M. D.; Williams, J. M.

    1993-01-01

    Space Sector, Defence Research Agency (DRA), Farnborough have been actively involved in the acquisition and processing of Earth Observation data for over 15 years. During that time an archive of over 20,000 items has been built up. This paper describes the major archive activities, including: operation and maintenance of the main DRA Archive, the development of a prototype Optical Disc Archive System (ODAS), the catalog systems in use at DRA, the UK Processing and Archive Facility for ERS-1 data, and future plans for archiving activities.

  5. ESA Fire CCI product assessment

    NASA Astrophysics Data System (ADS)

    Heil, Angelika; Yue, Chao; Mouillot, Florent; Storm, Thomas; Chuvieco, Emilio; Kaiser, Johannes

    2016-04-01

    Vegetation fires are a major disturbance in the Earth System. Fires change the biophysical properties and dynamics of ecosystems and alter terrestrial carbon pools. By altering the atmosphere's composition, fire emissions exert a significant climate forcing. To realistically model past and future changes of the Earth System, fire disturbances must be taken into account. Related modelling efforts require consistent global burned area observations covering at least 10 to 20 years. Guided by the specific requirements of a wide range of end users, the ESA fire_cci project is currently computing a new global burned area dataset. It applies a newly developed spectral change detection algorithm upon the full ENVISAT-MERIS archive (2002 to 2012). The algorithm relies on MODIS active fire information as "seed". A first, formally validated version has been released for the period 2006 to 2008. It comprises a pixel burned area product (spatial resolution of 333 m) with date detection information and a biweekly grid product at 0.5 degree spatial resolution. We compare fire_cci burned area with other global burned area products (MCD64, GFED4(s), GEOLAND) and a set of active fires data (hotspots from MODIS, TRMM, AATSR and fire radiative power from GFAS). Output from the ongoing processing of the full MERIS timeseries will be incorporated into the study, as far as available. The analysis of patterns of agreement and disagreement between fire_cci and other products provides a better understanding of product characteristics and uncertainties. The intercomparison of the 2006-2008 fire_cci time series shows a close agreement with GFED4 data in terms of global burned area and the general spatial and temporal patterns. Pronounced differences, however, emerge for specific regions or fire events. Burned area mapped by fire_cci tends to be notably higher in regions where small agricultural fires predominate. The improved detection of small agricultural fires by fire_cci can be related to

  6. Regular theta-firing neurons in the nucleus incertus during sustained hippocampal activation.

    PubMed

    Martínez-Bellver, Sergio; Cervera-Ferri, Ana; Martínez-Ricós, Joana; Ruiz-Torner, Amparo; Luque-Garcia, Aina; Luque-Martinez, Aina; Blasco-Serra, Arantxa; Guerrero-Martínez, Juan; Bataller-Mompeán, Manuel; Teruel-Martí, Vicent

    2015-04-01

    This paper describes the existence of theta-coupled neuronal activity in the nucleus incertus (NI). Theta rhythm is relevant for cognitive processes such as spatial navigation and memory processing, and can be recorded in a number of structures related to the hippocampal activation including the NI. Strong evidence supports the role of this tegmental nucleus in neural circuits integrating behavioural activation with the hippocampal theta rhythm. Theta oscillations have been recorded in the local field potential of the NI, highly coupled to the hippocampal waves, although no rhythmical activity has been reported in neurons of this nucleus. The present work analyses the neuronal activity in the NI in conditions leading to sustained hippocampal theta in the urethane-anaesthetised rat, in order to test whether such activation elicits a differential firing pattern. Wavelet analysis has been used to better define the neuronal activity already described in the nucleus, i.e., non-rhythmical neurons firing at theta frequency (type I neurons) and fast-firing rhythmical neurons (type II). However, the most remarkable finding was that sustained stimulation activated regular-theta neurons (type III), which were almost silent in baseline conditions and have not previously been reported. Thus, we describe the electrophysiological properties of type III neurons, focusing on their coupling to the hippocampal theta. Their spike rate, regularity and phase locking to the oscillations increased at the beginning of the stimulation, suggesting a role in the activation or reset of the oscillation. Further research is needed to address the specific contribution of these neurons to the entire circuit.

  7. Cirrus cloud properties derived from coincident GOES and lidar data during the 1986 FIRE Cirrus Intensive Field Observations (IFO)

    NASA Technical Reports Server (NTRS)

    Minnis, Patrick; Alvarez, Jose M.; Young, David F.; Heck, Patrick W.; Sassen, Kenneth

    1990-01-01

    One of the main difficulties in detecting cirrus clouds and determining their correct altitude using satellite measurements is their nonblackness. In the present algorithm (Rossow et al., 1985) used by the International Satellite Cloud Climatology Project (ISCCP), the cirrus cloud emissivity is estimated from the derived cloud reflectance using a theoretical model relating visible (VIS, 0.65 micron) optical depth to infrared (IR, 10.5 micron) emissivity. At this time, it is unknown how accurate this approach is or how the derived cloud altitude relates to the physical properties of the cloud. The First ISCCP Regional Experiment (FIRE) presents opportunities for determining how the observed radiances depend on the cloud properties. During the FIRE Cirrus Intensive Field Observations (IFO, see Starr, 1987), time series of cloud thickness, height, and relative optical densities were measured from several surface-based lidars. Cloud microphysics and radiances at various wavelengths were also measured simultaneously over these sites from aircraft at specific times during the IFO (October 19 to November 2, 1986). Satellite-observed radiances taken simultaneously can be matched with these data to determine their relationships to the cirrus characteristics. The first step is taken toward relating all of these variables to the satellite observations. Lidar-derived cloud heights are used to determine cloud temperatures which are used to estimate cloud emissivities from the satellite IR radiances. These results are then correlated to the observed VIS reflectances for various solar zenith angles.

  8. Injection of mineral dust into the free troposphere during fire events observed with polarization lidar at Limassol, Cyprus

    NASA Astrophysics Data System (ADS)

    Nisantzi, A.; Mamouri, R. E.; Ansmann, A.; Hadjimitsis, D.

    2014-06-01

    Four-year observations (2010-2014) with EARLINET polarization lidar and AERONET sun/sky photometer at Limassol (34.7° N, 33° E), Cyprus, were used to study the soil dust content in lofted fire smoke plumes advected from Turkey. This first systematic attempt to characterize less than 3 days old smoke plumes in terms of particle depolarization contributes to the more general effort to properly describe the life cycle of free-tropospheric smoke-dust mixtures from the emission event to phases of long-range transport (>4 days after emission). We found significant differences in the particle depolarization ratio (PDR) with values from 9-18% in lofted aerosol layers when Turkish fires contributed to the aerosol burden and of 3-13% when Turkish fires were absent. High Ångström exponents of 1.4-2.2 during all these events with lofted smoke layers, occuring between 1 and 3 km height, suggest the absence of a pronounced particle coarse mode. When plotted vs. the travel time (spatial distance between Limassol and last fire area), PDR decreased strongly from initial values around 16-18% (one day travel) to 4-8% after 4 days of travel caused by deposition processes. This behavior was found to be in close agreement with the literature. Computation of particle extinction coefficient and mass concentrations, separately for fine-mode dust, coarse-mode dust, and non-dust aerosol components show extinction-related dust fractions of the order of 10% (for PDR = 4%, travel times >4 days) and 50% (PDR = 15%, one day travel time) and mass-related dust fractions of 25% (PDR = 4%) to 80% (PDR = 15%). Biomass burning should be considered as another source of free tropospheric soil dust.

  9. Zaca Fire

    NASA Technical Reports Server (NTRS)

    2007-01-01

    On August 7, 2007, the Zaca fire continued to burn in the Los Padres National Forest near Santa Barbara, California. The fire started more than a month ago, on July 4, and has burned 69,800 acres. The fire remains in steep, rocky terrain with poor access. The continued poor access makes containment difficult in the wilderness area on the eastern flank. So far only one outbuilding has been destroyed; but over 450 homes are currently threatened. Over 2300 fire personnel, aided by four air tankers and 15 helicopters, are working to contain this massive fire. Full containment is expected on September 1.

    The image covers 45.2 x 46.1 km, and is centered near 34.6 degrees north latitude, 119.7 degrees west longitude.

    With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER images Earth to map and monitor the changing surface of our planet.

    ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra spacecraft. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products.

    The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping, and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission

  10. Vegetation Response to Holocene Variations in Climate and Fire Activity in Southwestern Oregon

    NASA Astrophysics Data System (ADS)

    White, A.; Briles, C.; Whitlock, C. L.

    2014-12-01

    Past ecosystem responses to fire and climate change have been well studied in many parts of the Pacific Northwest, but forest history of the southern Cascades is poorly understood. Pollen and charcoal records from Hobart Lake (42.099°N, 122.482°W, 1458m) in southwestern Oregon were analyzed to reconstruct past changes in vegetation and fire activity. The watershed today supports mixed conifer forest of Abies, Pseudotsuga, Cupressaceae, and Pinus. From 8000 to 3500 cal yr BP, the forest had more xerophytic species, such as Pinus and Cupressaceae, and higher frequency of fires than at present, suggesting a climate that was warmer and drier than current conditions. The last 3500 cal years was characterized by increasing mesophytic taxa, such as Abies and Pseudotsuga, and decreasing fire activity; these trends are consistent with the establishment of cooler wetter conditions in the late Holocene. Changes in the abundance of Abies and Pseudotsuga pollen were compared at multiple sites to better understand their history in relation to long-term variations in climate and local disturbance. The pollen record suggests that Abies (i.e., Abies concolor, A. magnifica, A. amabilis or A. grandis) was abundant during the late-glacial period in a widespread subalpine forest that was present at all elevations. The genus declined in abundance during the early Holocene when it was best represented at higher elevations. Abies species gradually became more widespread and abundant during the mid- and late Holocene consistent with cooler conditions and expansion of closed mesic forest. Pseudotsuga was most abundant at low-elevation sites in the Coast and Cascade ranges during the early Holocene and then most abundant in more southern, mid-elevation sites in the Klamath and southern Cascade ranges in the late Holocene. Thus, the regional conifer history was strongly governed by variations in the summer insolation as they relate to changes in summer effective moisture.

  11. Ca(2+)-activated ion currents triggered by ryanodine receptor-mediated Ca(2+) release control firing of inhibitory neurons in the prepositus hypoglossi nucleus.

    PubMed

    Saito, Yasuhiko; Yanagawa, Yuchio

    2013-01-01

    Spontaneous miniature outward currents (SMOCs) are known to exist in smooth muscles and peripheral neurons, and evidence for the presence of SMOCs in central neurons has been accumulating. SMOCs in central neurons are induced through Ca(2+)-activated K(+) (K(Ca)) channels, which are activated through Ca(2+)-induced Ca(2+) release from the endoplasmic reticulum via ryanodine receptors (RyRs). Previously, we found that some neurons in the prepositus hypoglossi nucleus (PHN) showed spontaneous outward currents (SOCs). In the present study, we used whole cell recordings in slice preparations of the rat brain stem to investigate the following: 1) the ionic mechanisms of SOCs, 2) the types of neurons exhibiting frequent SOCs, and 3) the effect of Ca(2+)-activated conductance on neuronal firing. Pharmacological analyses revealed that SOCs were induced via the activation of small-conductance-type K(Ca) (SK) channels and RyRs, indicating that SOCs correspond to SMOCs. An analysis of the voltage responses to current pulses of the fluorescence-expressing inhibitory neurons of transgenic rats revealed that inhibitory neurons frequently exhibited SOCs. Abolition of SOCs via blockade of SK channels enhanced the frequency of spontaneous firing of inhibitory PHN neurons. However, abolition of SOCs via blockade of RyRs reduced the firing frequency and hyperpolarized the membrane potential. Similar reductions in firing frequency and hyperpolarization were also observed when Ca(2+)-activated nonselective cation (CAN) channels were blocked. These results suggest that, in inhibitory neurons in the PHN, Ca(2+) release via RyRs activates SK and CAN channels, and these channels regulate spontaneous firing in a complementary manner.

  12. Integrated Active Fire Retrievals and Biomass Burning Emissions Using Complementary Near-Coincident Ground, Airborne and Spaceborne Sensor Data

    NASA Technical Reports Server (NTRS)

    Schroeder, Wilfrid; Ellicott, Evan; Ichoku, Charles; Ellison, Luke; Dickinson, Matthew B.; Ottmar, Roger D.; Clements, Craig; Hall, Dianne; Ambrosia, Vincent; Kremens, Robert

    2013-01-01

    Ground, airborne and spaceborne data were collected for a 450 ha prescribed fire implemented on 18 October 2011 at the Henry W. Coe State Park in California. The integration of various data elements allowed near coincident active fire retrievals to be estimated. The Autonomous Modular Sensor-Wildfire (AMS) airborne multispectral imaging system was used as a bridge between ground and spaceborne data sets providing high quality reference information to support satellite fire retrieval error analyses and fire emissions estimates. We found excellent agreement between peak fire radiant heat flux data (less than 1% error) derived from near-coincident ground radiometers and AMS. Both MODIS and GOES imager active fire products were negatively influenced by the presence of thick smoke, which was misclassified as cloud by their algorithms, leading to the omission of fire pixels beneath the smoke, and resulting in the underestimation of their retrieved fire radiative power (FRP) values for the burn plot, compared to the reference airborne data. Agreement between airborne and spaceborne FRP data improved significantly after correction for omission errors and atmospheric attenuation, resulting in as low as 5 difference between AquaMODIS and AMS. Use of in situ fuel and fire energy estimates in combination with a collection of AMS, MODIS, and GOES FRP retrievals provided a fuel consumption factor of 0.261 kg per MJ, total energy release of 14.5 x 10(exp 6) MJ, and total fuel consumption of 3.8 x 10(exp 6) kg. Fire emissions were calculated using two separate techniques, resulting in as low as 15 difference for various species

  13. Phenotypic plasticity of post-fire activity and thermal biology of a free-ranging small mammal.

    PubMed

    Stawski, Clare; Körtner, Gerhard; Nowack, Julia; Geiser, Fritz

    2016-05-15

    Ecosystems can change rapidly and sometimes irreversibly due to a number of anthropogenic and natural factors, such as deforestation and fire. How individual animals exposed to such changes respond behaviourally and physiologically is poorly understood. We quantified the phenotypic plasticity of activity patterns and torpor use - a highly efficient energy conservation mechanism - in brown antechinus (Antechinus stuartii), a small Australian marsupial mammal. We compared groups in densely vegetated forest areas (pre-fire and control) with a group in a burned, open habitat (post-fire). Activity and torpor patterns differed among groups and sexes. Females in the post-fire group spent significantly less time active than the other groups, both during the day and night. However, in males only daytime activity declined in the post-fire group, although overall activity was also reduced on cold days in males for all groups. The reduction in total or diurnal activity in the post-fire group was made energetically possible by a ~3.4-fold and ~2.2-fold increase in the proportion of time females and males, respectively, used torpor in comparison to that in the pre-fire and control groups. Overall, likely due to reproductive needs, torpor was more pronounced in females than in males, but low ambient temperatures increased torpor bout duration in both sexes. Importantly, for both male and female antechinus and likely other small mammals, predator avoidance and energy conservation - achieved by reduced activity and increased torpor use - appear to be vital for post-fire survival where ground cover and refuges have been obliterated.

  14. Transition in subicular burst firing neurons from epileptiform activity to suppressed state by feedforward inhibition.

    PubMed

    Sah, Nirnath; Sikdar, Sujit K

    2013-08-01

    The subiculum, a para-hippocampal structure positioned between the cornu ammonis 1 subfield and the entorhinal cortex, has been implicated in temporal lobe epilepsy in human patients and in animal models of epilepsy. The structure is characterized by the presence of a significant population of burst firing neurons that has been shown previously to lead epileptiform activity locally. Phase transitions in epileptiform activity in neurons following a prolonged challenge with an epileptogenic stimulus has been shown in other brain structures, but not in the subiculum. Considering the importance of the subicular burst firing neurons in the propagation of epileptiform activity to the entorhinal cortex, we have explored the phenomenon of phase transitions in the burst firing neurons of the subiculum in an in vitro rat brain slice model of epileptogenesis. Whole-cell patch-clamp and extracellular field recordings revealed a distinct phenomenon in the subiculum wherein an early hyperexcitable state was followed by a late suppressed state upon continuous perfusion with epileptogenic 4-aminopyridine and magnesium-free medium. The suppressed state was characterized by inhibitory post-synaptic potentials in pyramidal excitatory neurons and bursting activity in local fast-spiking interneurons at a frequency of 0.1-0.8 Hz. The inhibitory post-synaptic potentials were mediated by GABAA receptors that coincided with excitatory synaptic inputs to attenuate action potential discharge. These inhibitory post-synaptic potentials ceased following a cut between the cornu ammonis 1 and subiculum. The suppression of epileptiform activity in the subiculum thus represents a homeostatic response towards the induced hyperexcitability. Our results suggest the importance of feedforward inhibition in exerting this homeostatic control.

  15. 77 FR 1945 - Agency Information Collection Activities: Proposed Collection; Comment Request, National Fire...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-12

    ...; Comment Request, National Fire Department Census AGENCY: Federal Emergency Management Agency, DHS. ACTION... collect data for the development and continuation of the National Fire Department Census. DATES: Comments..., Statistician, United States Fire Administration, National Fire Data Center, (301) 447-1154 for...

  16. Co-emergence of multi-scale cortical activities of irregular firing, oscillations and avalanches achieves cost-efficient information capacity.

    PubMed

    Yang, Dong-Ping; Zhou, Hai-Jun; Zhou, Changsong

    2017-02-01

    The brain is highly energy consuming, therefore is under strong selective pressure to achieve cost-efficiency in both cortical connectivities and activities. However, cost-efficiency as a design principle for cortical activities has been rarely studied. Especially it is not clear how cost-efficiency is related to ubiquitously observed multi-scale properties: irregular firing, oscillations and neuronal avalanches. Here we demonstrate that these prominent properties can be simultaneously observed in a generic, biologically plausible neural circuit model that captures excitation-inhibition balance and realistic dynamics of synaptic conductance. Their co-emergence achieves minimal energy cost as well as maximal energy efficiency on information capacity, when neuronal firing are coordinated and shaped by moderate synchrony to reduce otherwise redundant spikes, and the dynamical clusterings are maintained in the form of neuronal avalanches. Such cost-efficient neural dynamics can be employed as a foundation for further efficient information processing under energy constraint.

  17. Co-emergence of multi-scale cortical activities of irregular firing, oscillations and avalanches achieves cost-efficient information capacity

    PubMed Central

    Zhou, Hai-Jun; Zhou, Changsong

    2017-01-01

    The brain is highly energy consuming, therefore is under strong selective pressure to achieve cost-efficiency in both cortical connectivities and activities. However, cost-efficiency as a design principle for cortical activities has been rarely studied. Especially it is not clear how cost-efficiency is related to ubiquitously observed multi-scale properties: irregular firing, oscillations and neuronal avalanches. Here we demonstrate that these prominent properties can be simultaneously observed in a generic, biologically plausible neural circuit model that captures excitation-inhibition balance and realistic dynamics of synaptic conductance. Their co-emergence achieves minimal energy cost as well as maximal energy efficiency on information capacity, when neuronal firing are coordinated and shaped by moderate synchrony to reduce otherwise redundant spikes, and the dynamical clusterings are maintained in the form of neuronal avalanches. Such cost-efficient neural dynamics can be employed as a foundation for further efficient information processing under energy constraint. PMID:28192429

  18. PDF neuron firing phase-shifts key circadian activity neurons in Drosophila.

    PubMed

    Guo, Fang; Cerullo, Isadora; Chen, Xiao; Rosbash, Michael

    2014-06-17

    Our experiments address two long-standing models for the function of the Drosophila brain circadian network: a dual oscillator model, which emphasizes the primacy of PDF-containing neurons, and a cell-autonomous model for circadian phase adjustment. We identify five different circadian (E) neurons that are a major source of rhythmicity and locomotor activity. Brief firing of PDF cells at different times of day generates a phase response curve (PRC), which mimics a light-mediated PRC and requires PDF receptor expression in the five E neurons. Firing also resembles light by causing TIM degradation in downstream neurons. Unlike light however, firing-mediated phase-shifting is CRY-independent and exploits the E3 ligase component CUL-3 in the early night to degrade TIM. Our results suggest that PDF neurons integrate light information and then modulate the phase of E cell oscillations and behavioral rhythms. The results also explain how fly brain rhythms persist in constant darkness and without CRY.

  19. HEROES Observations of a Quiescent Active Region

    NASA Astrophysics Data System (ADS)

    Shih, A. Y.; Christe, S.; Gaskin, J.; Wilson-Hodge, C.

    2014-12-01

    Hard X-ray (HXR) observations of solar flares reveal the signatures of energetic electrons, and HXR images with high dynamic range and high sensitivity can distinguish between where electrons are accelerated and where they stop. Even in the non-flaring corona, high-sensitivity HXR measurements may be able to detect the presence of electron acceleration. The High Energy Replicated Optics to Explore the Sun (HEROES) balloon mission added the capability of solar observations to an existing astrophysics balloon payload, HERO, which used grazing-incidence optics for direct HXR imaging. HEROES measures HXR emission from ~20 to ~75 keV with an angular resolution of 33" HPD. HEROES launched on 2013 September 21 from Fort Sumner, New Mexico, and had a successful one-day flight. We present the detailed analysis of the 7-hour observation of AR 11850, which sets new upper limits on the HXR emission from a quiescent active region, with corresponding constraints on the numbers of tens of keV energetic electrons present. Using the imaging capability of HEROES, HXR upper limits are also obtained for the quiet Sun surrounding the active region. We also discuss what can be achieved with new and improved HXR instrumentation on balloons.

  20. CH4 and CO distributions over tropical fires during October 2006 as observed by the Aura TES satellite instrument and modeled by GEOS-Chem

    NASA Astrophysics Data System (ADS)

    Worden, J.; Wecht, K.; Frankenberg, C.; Alvarado, M.; Bowman, K.; Kort, E.; Kulawik, S.; Lee, M.; Payne, V.; Worden, H.

    2013-04-01

    Tropical fires represent a highly uncertain source of atmospheric methane (CH4) because of the variability of fire emissions and the dependency of the fire CH4 emission factors (g kg-1 dry matter burned) on fuel type and combustion phase. In this paper we use new observations of CH4 and CO in the free troposphere from the Aura Tropospheric Emission Sounder (TES) satellite instrument to place constraints on the role of tropical fire emissions versus microbial production (e.g. in wetlands and livestock) during the (October) 2006 El Niño, a time of significant fire emissions from Indonesia. We first compare the global CH4 distributions from TES using the GEOS-Chem model. We find a mean bias between the observations and model of 26.3 ppb CH4 that is independent of latitude between 50° S and 80° N, consistent with previous validation studies of TES CH4 retrievals using aircraft measurements. The slope of the distribution of CH4 versus CO as observed by TES and modeled by GEOS-Chem is consistent (within the TES observation error) for air parcels over the Indonesian peat fires, South America, and Africa. The CH4 and CO distributions are correlated between R = 0.42 and R = 0.46, with these correlations primarily limited by the TES random error. Over Indonesia, the observed slope of 0.13 (ppb ppb-1) ±0.01, as compared to a modeled slope of 0.153 (ppb ppb-1) ±0.005 and an emission ratio used within the GEOS-Chem model of approximately 0.11 (ppb ppb-1), indicates that most of the observed methane enhancement originated from the fire. Slopes of 0.47 (ppb ppb-1) ±0.04 and 0.44 (ppb ppb-1) ±0.03 over South America and Africa show that the methane in the observed air parcels primarily came from microbial-generated emissions. Sensitivity studies using GEOS-Chem show that part of the observed correlation for the Indonesian observations and most of the observed correlations over South America and Africa are a result of transport and mixing of the fire and nearby microbial

  1. CH4 and CO distributions over tropical fires as observed by the Aura TES satellite instrument and modeled by GEOS-Chem

    NASA Astrophysics Data System (ADS)

    Worden, J.; Wecht, K.; Frankenberg, C.; Alvarado, M.; Bowman, K.; Kort, E.; Kulawik, S.; Lee, M.; Payne, V.; Worden, H.

    2012-10-01

    Tropical fires represent a highly uncertain source of atmospheric methane (CH4) because of the variability of fire emissions and the dependency of the fire CH4 emission factors (g kg-1 dry matter burned) on fuel type and combustion phase. In this paper we use new observations of CH4 and CO in the free troposphere from the Aura Tropospheric Emission Sounder (TES) satellite instrument to place constraints on the role of tropical fire emissions versus microbial production (e.g. in wetlands and livestock) during the (October) 2006 El Nino, a time of significant peat fire emissions from Indonesia We first evaluate the global CH4 distributions from TES using the GEOS-Chem model. We find a mean bias between the observations and model of 26.3 ppb CH4 that is independent of latitude between 50° S and 80° N consistent with previous validation studies of TES CH4 retrievals using aircraft measurements. The slope of the distribution of CH4 versus CO as observed by TES and modeled by GEOS-Chem is consistent (within the TES observation error) for air parcels over the Indonesian peat fires, South America, and Africa. The CH4 and CO distributions are correlated between R = 0.42 and R = 0.46, with these correlations primarily limited by the TES random error. Over Indonesia, the observed slope of 0.13 (ppb ppb-1) ± 0.01, as compared to a modeled slop of 0.153 (ppb ppb-1) ± 0.005 and an emission ratio used within the GEOS-Chem model of approximately 0.11 (ppb ppb-1) indicates that most of the observed methane enhancement originated from the fire. Slopes of 0.47 (ppb ppb-1) ± 0.04 and 0.44 (ppb ppb-1) ± 0.03 over South America and Africa show that the methane in the observed air parcels primarily came from microbial generated emissions. Sensitivity studies using GEOS-Chem show that part of the observed correlation for the Indonesian observations and most of the observed correlations over South America and Africa are a result of transport and mixing of the fire and nearby

  2. CO2 lidar observations of Mount Pinatubo debris: FIRE 2 and longer-term measurements

    NASA Technical Reports Server (NTRS)

    Levinson, David H.; Post, Madison J.; Grund, Christian J.

    1993-01-01

    The volcanic debris in the stratosphere from the June 1991 eruption of Mt. Pinatubo first appeared over the NOAA Wave Propagation Laboratory (WPL) field site near Boulder, Colorado (40.15 N, 105.23 W), in July of 1991. The presence of the Pinatubo cloud has allowed us to characterize both the tropospheric and stratospheric aerosol backscatter using the NOAA/WPL CO2 Doppler lidar. The lidar has measured vertical backscatter profiles at lambda = 10.59 mu m for over a decade. Analysis of this dense set of profiles reveals the effects of atmospheric and microphysical processes during the buildup and decay of Mt. Pinatubo's clouds. Further information on the NOAA lidar, specifically calibrations using a hard target, can be found in Post and Cupp (1990). We present results of those measurements for June 15, 1991, through December 31, 1992. During that period of longer-term measurements, WPL took part in FIRE II (First ISCCP (International Satellite Cloud Climatology Project) Regional Experiment II), from November 12 through December 8, 1991, measuring vertical backscatter profiles almost daily. One of the mechanisms for purging stratospheric aerosols is tropopause folding, which occurs in cold-core extratropical cyclones. Tropospheric mass loading occurs during folding events which can substantially increase the amount of ice nuclei in the upper troposphere, and may affect the formation of cirrus in that region. Spring and fall are prominent times for tropopause folding events because of the migration of the subtropical and polar jet streams during the transition seasons. Sassen has suggested that the volcanic aerosols from Pinatubo played a role in the formation of cirrus during FIRE II, particularly during a period of moist subtropical flow on December 5-6, 1991.

  3. MESSENGER Observations of Substorm Activity at Mercury

    NASA Astrophysics Data System (ADS)

    Sun, W. J.; Slavin, J. A.; Fu, S.; Raines, J. M.; Zong, Q. G.; Poh, G.; Jia, X.; Sundberg, T.; Gershman, D. J.; Pu, Z.; Zurbuchen, T.; Shi, Q.

    2015-12-01

    MErcury Surface, Space ENviroment, GEochemistry, and Ranging (MESSENGER) magnetic field and plasma measurements taken during crossings of Mercury's magnetotail from 2011 to 2014 have been investigated for substorms. A number of events with clear Earth-like growth phase and expansion phase signatures were found. The thinning of the plasma sheet and the increase of magnetic field intensity in the lobe were observed during the growth phase and plasma sheet was observed to thicken during the expansion phase, which are similar to the observations at Earth. But the time scale of Mercury's substorm is only several minutes comparing with the several hours at Earth [Sun et al., 2015a]. Detailed analysis of magnetic field fluctuations during the substorm expansion phase have revealed low frequency plasma waves, e.g. Pi2-like pulsations. The By fluctuations accompanying substorm dipolarizations are consistent with pulses of field-aligned currents near the high latitude edge of the plasma sheet. Further study shows that they are near-circularly polarized electromagnetic waves, most likely Alfvén waves. Soon afterwards the plasma sheet thickened and MESSENGER detected a series of compressional waves. We have also discussed their possible sources [Sun et al., 2015b]. Sun, W.-J., J. A. Slavin, S. Y. Fu, et al. (2015a), MESSENGER observations of magnetospheric substorm activity in Mercury's near magnetotail. Geophys. Res. Lett., 42, 3692-3699. doi: 10.1002/2015GL064052.Sun, W.-J., J. A. Slavin, S. Y. Fu, et al. (2015b), MESSENGER observations of Alfvénic and compressional waves during Mercury's substorms. Geophys. Res. Lett., 42, in press. doi: 10.1002/ 2015GL065452.

  4. Contributions of microbial activity and ash deposition to post-fire nitrogen availability in a pine savanna

    NASA Astrophysics Data System (ADS)

    Ficken, Cari D.; Wright, Justin P.

    2017-01-01

    Many ecosystems experience drastic changes to soil nutrient availability associated with fire, but the magnitude and duration of these changes are highly variable among vegetation and fire types. In pyrogenic pine savannas across the southeastern United States, pulses of soil inorganic nitrogen (N) occur in tandem with ecosystem-scale nutrient losses from prescribed burns. Despite the importance of this management tool for restoring and maintaining fire-dependent plant communities, the contributions of different mechanisms underlying fire-associated changes to soil N availability remain unclear. Pulses of N availability following fire have been hypothesized to occur through (1) changes to microbial cycling rates and (2) direct ash deposition. Here, we document fire-associated changes to N availability across the growing season in a longleaf pine savanna in North Carolina. To differentiate between possible mechanisms driving soil N pulses, we measured net microbial cycling rates and changes to soil δ15N before and after a burn. Our findings refute both proposed mechanisms: we found no evidence for changes in microbial activity, and limited evidence that ash deposition could account for the increase in ammonium availability to more than 5-25 times background levels. Consequently, we propose a third mechanism to explain post-fire patterns of soil N availability, namely that (3) changes to plant sink strength may contribute to ephemeral increases in soil N availability, and encourage future studies to explicitly test this mechanism.

  5. Projected changes in daily fire spread across Canada over the next century

    NASA Astrophysics Data System (ADS)

    Wang, Xianli; Parisien, Marc-André; Taylor, Steve W.; Candau, Jean-Noël; Stralberg, Diana; Marshall, Ginny A.; Little, John M.; Flannigan, Mike D.

    2017-02-01

    In the face of climate change, predicting and understanding future fire regimes across Canada is a high priority for wildland fire research and management. Due in large part to the difficulties in obtaining future daily fire weather projections, one of the major challenges in predicting future fire activity is to estimate how much of the change in weather potential could translate into on-the-ground fire spread. As a result, past studies have used monthly, annual, or multi-decadal weather projections to predict future fires, thereby sacrificing information relevant to day-to-day fire spread. Using climate projections from the fifth phase of the Coupled Model Intercomparison Project (CMIP5), historical weather observations, MODIS fire detection data, and the national fire database of Canada, this study investigated potential changes in the number of active burning days of wildfires by relating ‘spread days’ to patterns of daily fire-conducive weather. Results suggest that climate change over the next century may have significant impacts on fire spread days in almost all parts of Canada’s forested landmass; the number of fire spread days could experience a 2-to-3-fold increase under a high CO2 forcing scenario in eastern Canada, and a greater than 50% increase in western Canada, where the fire potential is already high. The change in future fire spread is critical in understanding fire regime changes, but is also imminently relevant to fire management operations and in fire risk mitigation.

  6. NASA Fire Protection Coordinators' Conference

    NASA Technical Reports Server (NTRS)

    Clark, Theodore

    2001-01-01

    Fire prevention activities at NASA's Stennis Space Center are reviewed in this viewgraph presentation. The Fire Prevention Office of the Fire Department at NASA Stennis conducts inspections and issues small appliance permits, while the Operations Section responds to emergencies.

  7. Motor activity in the isolated spinal cord of the chick embryo: synaptic drive and firing pattern of single motoneurons.

    PubMed

    O'Donovan, M J

    1989-03-01

    The cellular mechanisms underlying embryonic motility were investigated using intracellular recording from motoneurons and electrotonic recording from muscle nerves during motor activity generated by an isolated spinal cord preparation of 12- to 15-d-old chick embryos. DC-coupled recordings from sartorius (a flexor) and femorotibialis (an extensor) muscle nerves revealed that both sets of motoneurons were depolarized at the same time in each cycle even when the motoneurons fired out of phase. Sartorius motoneurons fired briefly on the rising phase of the depolarization and then stopped firing before discharging a second burst of spikes as the depolarization decayed. By contrast, femorotibialis motoneurons fired at the peak of their depolarization, which was coincident with the interruption in sartorius activity. Intracellular recordings from antidromically identified motoneurons confirmed that flexor and extensor motoneurons were depolarized at the same time during each cycle of activity. The discharge of femorotibialis motoneurons, and others presumed to be extensors, followed changes in membrane potential so that maximal firing occurred during peak depolarization. The relationship between discharge and membrane potential was different in sartorius motoneurons (and in others presumed to be flexors) because they fired briefly on the rising phase of the depolarization and then stopped firing during peak depolarization. In some of these cells firing resumed as the membrane potential decayed back to rest. Intracellular injection of depolarizing current into sartorius motoneurons during motor activity reversed the direction of the membrane potential change from depolarizing to hyperpolarizing during the pause in sartorius discharge. In addition, the discharge evoked by the depolarizing current was blocked during the reversed part of the synaptic potential revealing its inhibitory nature. The occurrence of the IPSP was accompanied by a large reduction in motoneuronal

  8. Repeated Habitat Disturbances by Fire Decrease Local Effective Population Size.

    PubMed

    Schrey, Aaron W; Ragsdale, Alexandria K; McCoy, Earl D; Mushinsky, Henry R

    2016-07-01

    Effective population size is a fundamental parameter in population genetics, and factors that alter effective population size will shape the genetic characteristics of populations. Habitat disturbance may have a large effect on genetic characteristics of populations by influencing immigration and gene flow, particularly in fragmented habitats. We used the Florida Sand Skink (Plestiodon reynoldsi) to investigate the effect of fire-based habitat disturbances on the effective population size in the highly threatened, severely fragmented, and fire dependent Florida scrub habitat. We screened 7 microsatellite loci in 604 individuals collected from 12 locations at Archbold Biological Station. Archbold Biological Station has an active fire management plan and detailed records of fires dating to 1967. Our objective was to determine how the timing, number, and intervals between fires affect effective population size, focusing on multiple fires in the same location. Effective population size was higher in areas that had not been burned for more than 10 years and decreased with number of fires and shorter time between fires. A similar pattern was observed in abundance: increasing abundance with time-since-fire and decreasing abundance with number of fires. The ratio of effective population size to census size was higher at sites with more recent fires and tended to decrease with time-since-last-fire. These results suggest that habitat disturbances, such as fire, may have a large effect in the genetic characteristics of local populations and that Florida Sand Skinks are well adapted to the natural fire dynamics required to maintain Florida scrub.

  9. Assessing the Role of Vegetation Fires in CO Vertical Profile Anomalies in 2002-2012 with MOZAIC-IAGOS Airborne Observations

    NASA Astrophysics Data System (ADS)

    Petetin, H.

    2015-12-01

    Vegetation fires represent a major source of pollution throughout the troposphere, with strong impacts on the atmospheric composition, air quality and radiative balance. Among the myriad of compounds emitted by these fires, carbon monoxide represents one of the dominant species, and due to its long lifetime, can be transported over very large distances. In the framework of the MOZAIC-IAGOS program, carbon monoxide is routinely measured since 2002 by several commercial aircraft, which provides a unique dataset of CO vertical profiles throughout troposphere. In this study, we investigate the role of vegetation fires in the strong CO anomalies observed in troposphere during the 2002-2012 period. FLEXPART backward simulations coupled with anthropogenic and biomass burning emission inventories are used to trace the geographical origin of these anomalies, which provides valuable informations on the long-range transport of vegetation fire plumes and their subsequent impact on downwind regions.

  10. EUV Observations of Active Region Dynamics

    NASA Astrophysics Data System (ADS)

    Deluca, E. E.; Cirtain, J. W.; del Zanna, G.; Mason, H. E.; Martens, P. C.; Schmelz, J.; Golub, L.

    2005-05-01

    Data collected during SoHO JOP 146, in collaboration with TRACE, is used to investigate the physical characteristics of coronal active region loops as a function of time and position along and across loop structures. These data include TRACE images in all three EUV passbands, and simultaneous CDS spectroscopic observations. Preliminary measurements of the loop temperature both along the loop half-length and loop cross-section are presented as a function of time. We will show the temperature and density profiles of several structures as a function of position, show changes in temperature and density with time and characterize the coronal background emission. Questions raised by these results will be greatly advanced with the high resolution spectra available from the EIS on Solar-B.

  11. Assessment of post-fire changes of hydrological regime of watersheds based on the analysis of remote sensing data and standard hydrometeorological observations

    NASA Astrophysics Data System (ADS)

    Semenova, Olga; Mikheeva, Anna; Nesterova, Natalia; Lebedeva, Luidmila

    2016-04-01

    Forest fires are regular at large territories of Siberia. Fire occurrence is expected to increase in the future due to climate change and anthropogenic influence. Though there are many studies on vegetation and landscapes transformation after fire the analysis of associated hydrological and geomorphologic changes in permafrost environments in Russia are rare. Broadening our previous study on fire impact on hydrology in remote area of the Baikal region (Semenova et al., 2015a, b; Lebedeva et al., 2014) the following objectives for this study were set up: i) describe changes in streamflow after extensive 2003 forest fire in several middle-size river basins in Siberian permafrost zone ii) assess change in sediment flux after the fire in the same catchments iii) attribute found responses to dominating landscapes and the level of vegetation disturbance and other factors, iv) analyze the mechanisms of those changes using the analysis of ground and remote sensing data. Following severe drought 2002-2003 extensive fires occurred in spring and summer of 2003 in the southeast part of Russia when more than 20 million ha were affected by disaster. Vast remote regions in Transbaikal region lack any special observations on fire impact of 2003 on hydrological regime of disturbed areas. Therefore hydrological data on water and suspended sediment flow from standard network of Russian Hydrometeorological Service was used combined with remote sensing data analysis to assess post-fire changes. Six watersheds in the upstreams of the Vitim River located at the Vitim Plateau are chosen for this study. In our analysis we used daily river discharge data for 6 gauges and 10-days average suspended sediment discharge for 3 gauges. Semenova et al. (2015a, b) detected short-term impact of fire on runoff manifested in significant increase (up to 40-50 %) of summer flow after the fire. The analysis of suspended sediment data revealed that the impact of fire on sediment flow regime can be traced

  12. The Relationship between Particulate Pollution Levels in Australian Cities, Meteorology, and Landscape Fire Activity Detected from MODIS Hotspots

    PubMed Central

    Price, Owen F.; Williamson, Grant J.; Henderson, Sarah B.; Johnston, Fay; Bowman, David M. J. S.

    2012-01-01

    Smoke from bushfires is an emerging issue for fire managers because of increasing evidence for its public health effects. Development of forecasting models to predict future pollution levels based on the relationship between bushfire activity and current pollution levels would be a useful management tool. As a first step, we use daily thermal anomalies detected by the MODIS Active Fire Product (referred to as “hotspots”), pollution concentrations, and meteorological data for the years 2002 to 2008, to examine the statistical relationship between fire activity in the landscapes and pollution levels around Perth and Sydney, two large Australian cities. Resultant models were statistically significant, but differed in their goodness of fit and the distance at which the strength of the relationship was strongest. For Sydney, a univariate model for hotspot activity within 100 km explained 24% of variation in pollution levels, and the best model including atmospheric variables explained 56% of variation. For Perth, the best radius was 400 km, explaining only 7% of variation, while the model including atmospheric variables explained 31% of the variation. Pollution was higher when the atmosphere was more stable and in the presence of on-shore winds, whereas there was no effect of wind blowing from the fires toward the pollution monitors. Our analysis shows there is a good prospect for developing region-specific forecasting tools combining hotspot fire activity with meteorological data. PMID:23071788

  13. The relationship between particulate pollution levels in Australian cities, meteorology, and landscape fire activity detected from MODIS hotspots.

    PubMed

    Price, Owen F; Williamson, Grant J; Henderson, Sarah B; Johnston, Fay; Bowman, David M J S

    2012-01-01

    Smoke from bushfires is an emerging issue for fire managers because of increasing evidence for its public health effects. Development of forecasting models to predict future pollution levels based on the relationship between bushfire activity and current pollution levels would be a useful management tool. As a first step, we use daily thermal anomalies detected by the MODIS Active Fire Product (referred to as "hotspots"), pollution concentrations, and meteorological data for the years 2002 to 2008, to examine the statistical relationship between fire activity in the landscapes and pollution levels around Perth and Sydney, two large Australian cities. Resultant models were statistically significant, but differed in their goodness of fit and the distance at which the strength of the relationship was strongest. For Sydney, a univariate model for hotspot activity within 100 km explained 24% of variation in pollution levels, and the best model including atmospheric variables explained 56% of variation. For Perth, the best radius was 400 km, explaining only 7% of variation, while the model including atmospheric variables explained 31% of the variation. Pollution was higher when the atmosphere was more stable and in the presence of on-shore winds, whereas there was no effect of wind blowing from the fires toward the pollution monitors. Our analysis shows there is a good prospect for developing region-specific forecasting tools combining hotspot fire activity with meteorological data.

  14. Influence of agricultural activities, forest fires and agro-industries on air quality in Thailand.

    PubMed

    Phairuang, Worradorn; Hata, Mitsuhiko; Furuuchi, Masami

    2017-02-01

    Annual and monthly-based emission inventories in northern, central and north-eastern provinces in Thailand, where agriculture and related agro-industries are very intensive, were estimated to evaluate the contribution of agricultural activity, including crop residue burning, forest fires and related agro-industries on air quality monitored in corresponding provinces. The monthly-based emission inventories of air pollutants, or, particulate matter (PM), NOx and SO2, for various agricultural crops were estimated based on information on the level of production of typical crops: rice, corn, sugarcane, cassava, soybeans and potatoes using emission factors and other parameters related to country-specific values taking into account crop type and the local residue burning period. The estimated monthly emission inventory was compared with air monitoring data obtained at monitoring stations operated by the Pollution Control Department, Thailand (PCD) for validating the estimated emission inventory. The agro-industry that has the greatest impact on the regions being evaluated, is the sugar processing industry, which uses sugarcane as a raw material and its residue as fuel for the boiler. The backward trajectory analysis of the air mass arriving at the PCD station was calculated to confirm this influence. For the provinces being evaluated which are located in the upper northern, lower northern and northeast in Thailand, agricultural activities and forest fires were shown to be closely correlated to the ambient PM concentration while their contribution to the production of gaseous pollutants is much less.

  15. Fire activity as a function of fire–weather seasonal severity and antecedent climate across spatial scales in southern Europe and Pacific western USA

    USGS Publications Warehouse

    Urbieta, Itziar R.; Zavala, Gonzalo; Bedia, Joaquin; Gutierrez, Jose M.; San Miguel-Ayanz, Jesus; Camia, Andrea; Keeley, Jon E.; Moreno, Jose M.

    2015-01-01

    Climate has a strong influence on fire activity, varying across time and space. We analyzed the relationships between fire–weather conditions during the main fire season and antecedent water-balance conditions and fires in two Mediterranean-type regions with contrasted management histories: five southern countries of the European Union (EUMED)(all fires); the Pacific western coast of the USA (California and Oregon, PWUSA)(national forest fires). Total number of fires (≥1 ha), number of large fires (≥100 ha) and area burned were related to mean seasonal fire weather index (FWI), number of days over the 90th percentile of the FWI, and to the standardized precipitation-evapotranspiration index (SPEI) from the preceding 3 (spring) or 8 (autumn through spring) months. Calculations were made at three spatial aggregations in each area, and models related first-difference (year-to-year change) of fires and FWI/climate variables to minimize autocorrelation. An increase in mean seasonal FWI resulted in increases in the three fire variables across spatial scales in both regions. SPEI contributed little to explain fires, with few exceptions. Negative water-balance (dry) conditions from autumn through spring (SPEI8) were generally more important than positive conditions (moist) in spring (SPEI3), both of which contributed positively to fires. The R2 of the models generally improved with increasing area of aggregation. For total number of fires and area burned, the R2 of the models tended to decrease with increasing mean seasonal FWI. Thus, fires were more susceptible to change with climate variability in areas with less amenable conditions for fires (lower FWI) than in areas with higher mean FWI values. The relationships were similar in both regions, albeit weaker in PWUSA, probably due to the wider latitudinal gradient covered in PWUSA than in EUMED. The large variance explained by some of the models indicates that large-scale seasonal forecast could help anticipating

  16. Development of Observational Activities for Introductory Astronomy

    NASA Astrophysics Data System (ADS)

    Marshall, Kevin; Wilson, J.

    2007-05-01

    During the spring of 2006 new laboratory activities were developed for introductory astronomy classes at Georgia State University. The purpose of these labs was to develop hands-on astronomy activates. We first purchased Project Star refracting telescope kits and spectrometer kits, and a Meade Deep Sky Imager CCD. The new materials were tried on a single lab section of 22 students. For comparison purposes a traditional lab section from the same large lecture class was selected as a control group. The students in the experimental group constructed the telescopes and measured their telescope’s, light gathering ability and its angular resolution and compared them to the human eye, and its magnification. The students also built spectrometers and learned how to use them identify different types of light sources such as Mercury vapor lights, high and low pressure sodium lights, fluorescent lights, and other typical light sources. Each student then performed a light pollution investigation of their neighborhood using the spectroscopes they had constructed. In addition all students used these spectroscopes to observe solar Fraunhofer lines. In lab students used a small Schmidt-Cassegrain telescope and the Meade Deep Sky Imager to take photos of objects inside the lab room. After this they took telescopic pictures of the sun and moon on several occasions. The students rally enjoyed most of these activities. Student in the experimental group had slightly higher final exam scores than the students in the control group. However, the drop rate for the control group was higher then the experimental group and so the statistical significance of the result could not be determined. The authors would like to thank the Partnership for Reform in Science and Mathematics (PRISM), funded by NSF, for providing a mini-grant to support this work.

  17. FIRE Science Results 1989

    NASA Technical Reports Server (NTRS)

    Mcdougal, David S. (Editor)

    1990-01-01

    FIRE (First ISCCP Regional Experiment) is a U.S. cloud-radiation research program formed in 1984 to increase the basic understanding of cirrus and marine stratocumulus cloud systems, to develop realistic parameterizations for these systems, and to validate and improve ISCCP cloud product retrievals. Presentations of results culminating the first 5 years of FIRE research activities were highlighted. The 1986 Cirrus Intensive Field Observations (IFO), the 1987 Marine Stratocumulus IFO, the Extended Time Observations (ETO), and modeling activities are described. Collaborative efforts involving the comparison of multiple data sets, incorporation of data measurements into modeling activities, validation of ISCCP cloud parameters, and development of parameterization schemes for General Circulation Models (GCMs) are described.

  18. Defining global syndromes of fire and the relationship of these to biomes, climate and human activity

    NASA Astrophysics Data System (ADS)

    Lehmann, C.; Archibald, S.; Gomez-Dans, J.; Bradstock, R.

    2012-12-01

    Fire is a ubiquitous component of the Earth system that remains poorly understood. To date, global scale understanding of fire is limited largely to the annual extent of burning as detected by satellites. This is problematic because fire is multi-dimensional, and focus on individual metrics belies both the complexity and importance of fire within the Earth system. In an applied sense, the lack of a unified understanding of fire impedes estimation of GHG emissions or prediction of future fire regimes as a consequence of changing patterns of climate and land use. To address this we identified five key characteristics of fire regimes: size, frequency, intensity, season and extent. We combined new global datasets with existing datasets to examine cross-correlations among characteristics. We demonstrate that only certain combinations of fire characteristics are possible and this likely reflects fundamental energetic constraints derived from interactions between under-lying fuel types, climate and rates of re-growth post-fire. For example, very intense fires can only occur infrequently because a system requires a lengthy period to develop sufficient fuel to burn. Further, very cool fires only occur infrequently because fuels are not available to burn. Following, we applied a clustering algorithm to these data to determine whether we could identify syndromes of fire regimes. Pyromes, as global syndromes of fire are conceptually analogous to biomes (global syndromes of vegetation) where the extent of each pyrome is determined solely as a product of the fire characteristics themselves. A point of difference to biomes being that no one has previously attempted to quantify the global range of fire syndromes. We identified five pyromes, four of which we believe represent distinctions between crown, litter and grass-fuelled fires. The relationship of pyromes to biomes and climate are not deterministic as different biomes and climates may be represented within a single pyrome

  19. Somatostatinergic modulation of firing pattern and calcium-activated potassium currents in medium spiny neostriatal neurons.

    PubMed

    Galarraga, E; Vilchis, C; Tkatch, T; Salgado, H; Tecuapetla, F; Perez-Rosello, T; Perez-Garci, E; Hernandez-Echeagaray, E; Surmeier, D J; Bargas, J

    2007-05-11

    Somatostatin is synthesized and released by aspiny GABAergic interneurons of the neostriatum, some of them identified as low threshold spike generating neurons (LTS-interneurons). These neurons make synaptic contacts with spiny neostriatal projection neurons. However, very few somatostatin actions on projection neurons have been described. The present work reports that somatostatin modulates the Ca(2+) activated K(+) currents (K(Ca) currents) expressed by projection cells. These actions contribute in designing the firing pattern of the spiny projection neuron; which is the output of the neostriatum. Small conductance (SK) and large conductance (BK) K(Ca) currents represent between 30% and 50% of the sustained outward current in spiny cells. Somatostatin reduces SK-type K(+) currents and at the same time enhances BK-type K(+) currents. This dual effect enhances the fast component of the after hyperpolarizing potential while reducing the slow component. Somatostatin then modifies the firing pattern of spiny neurons which changed from a tonic regular pattern to an interrupted "stuttering"-like pattern. Semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) tissue expression analysis of dorsal striatal somatostatinergic receptors (SSTR) mRNA revealed that all five SSTR mRNAs are present. However, single cell RT-PCR profiling suggests that the most probable receptor in charge of this modulation is the SSTR2 receptor. Interestingly, aspiny interneurons may exhibit a "stuttering"-like firing pattern. Therefore, somatostatin actions appear to be the entrainment of projection neurons to the rhythms generated by some interneurons. Somatostatin is then capable of modifying the processing and output of the neostriatum.

  20. 77 FR 7171 - Agency Information Collection Activities: Proposed Collection; Comment Request, National Fire...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-10

    ...; Comment Request, National Fire Incident Reporting System (NFIRS) v5.0 AGENCY: Federal Emergency Management... National Fire Incident Reporting System (NFIRS) v5.0. The program provides a well established mechanism, using standardized reporting methods, to collect and analyze fire incident data at the Federal,...

  1. 76 FR 31364 - Agency Information Collection Activities; Submission for OMB Review; Comment Request; Fire Brigades

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-31

    ...; Fire Brigades ACTION: Notice. SUMMARY: The Department of Labor (DOL) is submitting the Occupational Safety and Health Administration (OSHA) sponsored information collection request (ICR) titled, ``Fire... INFORMATION: The Fire Brigade Standard codified at 29 CFR 1910.156 requires each covered employer...

  2. 78 FR 6133 - Agency Information Collection Activities; Submission for OMB Review; Comment Request; Fire...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-29

    ...; Fire Protection in Underground Coal Mines ACTION: Notice. SUMMARY: The Department of Labor (DOL) is...) revision titled, ``Fire Protection in Underground Coal Mines,'' to the Office of Management and Budget (OMB... event of an emergency. In addition, various sections of part 75 require fire drills to be...

  3. Analysis of Aircraft, Radiosonde and Radar Observations in Cirrus Clouds Observed During FIRE II: The Interactions Between Environmental Structure, Turbulence and Cloud Microphysical Properties

    NASA Technical Reports Server (NTRS)

    Smith, Samantha A.; DelGenio, Anthony D.

    1999-01-01

    Ways to determine the turbulence intensity and the horizontal variability in cirrus clouds have been investigated using FIRE-II aircraft, radiosonde and radar data. Higher turbulence intensities were found within some, but not all, of the neutrally stratified layers. It was also demonstrated that the stability of cirrus layers with high extinction values decrease in time, possibly as a result of radiative destabilization. However, these features could not be directly related to each other in any simple manner. A simple linear relationship was observed between the amount of horizontal variability in the ice water content and its average value. This was also true for the extinction and ice crystal number concentrations. A relationship was also suggested between the variability in cloud depth and the environmental stability across the depth of the cloud layer, which requires further investigation.

  4. Validation of satellite retrievals of cloud microsphysics and liquid water path using observations from FIRE

    NASA Technical Reports Server (NTRS)

    Rossow, W.; White, A.; Han, Q.; Welch, R.; Chou, J.

    1995-01-01

    Cloud effective radii (r(sub e)) and cloud liquid water path (LWP) are derived from ISCCP spatially sampled satellite data and validated with ground-based pyranometer and microwave radiometer measurements taken on San Nicolas Island during the 1987 FIRE IFO. Values of r(sub e) derived from the ISCCP data are also compared to values retrieved by a hybrid method that uses the combination of LWP derived from microwave measurement and optical thickness derived from GOES data. The results show that there is significant variability in cloud properties over a 100 km x 80 km area and that the values at San Nicolas Island are not necessarily representative of the surrounding cloud field. On the other hand, even though there were large spatial variations in optical depth, the r(sub e) values remained relatively constant (with sigma less than or equal to 2-3 microns in most cases) in the marine stratocumulus. Furthermore, values of r(sub e) derived from the upper portion of the cloud generally are representative of the entire stratiform cloud. When LWP values are less than 100 g m(exp -2), then LWP values derived from ISCCP data agree well with those values estimated from ground-based microwave measurements. In most cases LWP differences were less than 20 g m(exp -2). However, when LWP values become large (e.g., greater than or equal to 200 g m(exp -2)), then relative differences may be as large as 50%- 100%. There are two reasons for this discrepancy in the large LWP clouds: (1) larger vertical inhomogeneities in precipitating clouds and (2) sampling errors on days of high spatial variability of cloud optical thicknesses. Variations of r(sub e) in stratiform clouds may indicate drizzle: clouds with droplet sizes larger than 15 microns appear to be associated with drizzling, while those less than 10 microns are indicative of nonprecipitating clouds. Differences in r(sub e) values between the GOES and ISCCP datasets are found to be 0.16 +/- 0.98 micron.

  5. Models Constraints from Observations of Active Galaxies

    NASA Astrophysics Data System (ADS)

    Riffel, R.; Pastoriza, M. G.; Rodríguez-Ardila, A.; Dametto, N. Z.; Ruschel-Dutra, D.; Riffel, R. A.; Storchi-Bergmann, T.; Martins, L. P.; Mason, R.; Ho, L. C.; Palomar XD Team

    2015-08-01

    Studying the unresolved stellar content of galaxies generally involves disentangling the various components contributing to the spectral energy distribution (SED), and fitting a combination of simple stellar populations (SSPs) to derive information about age, metallicity, and star formation history. In the near-infrared (NIR, 0.85-2.5 μm), the thermally pulsing asymptotic giant branch (TP-AGB) phase - the last stage of the evolution of intermediate-mass (M ≲ 6 M⊙) stars - is a particularly important component of the SSP models. These stars can dominate the emission of stellar populations with ages ˜ 0.2-2 Gyr, being responsible for roughly half of the luminosity in the K band. In addition, when trying to describe the continuum observed in active galactic nuclei, the signatures of the central engine and from the dusty torus cannot be ignored. Over the past several years we have developed a method to disentangle these three components. Our synthesis shows significant differences between Seyfert 1 (Sy 1) and Seyfert 2 (Sy 2) galaxies. The central few hundred parsecs of our galaxy sample contain a substantial fraction of intermediate-age populations with a mean metallicity near solar. Two-dimensional mapping of the near-infrared stellar population of the nuclear region of active galaxies suggests that there is a spatial correlation between the intermediate-age stellar population and a partial ring of low stellar velocity dispersion (σ*). Such an age is consistent with a scenario in which the origin of the low-σ* rings is a past event which triggered an inflow of gas and formed stars which still keep the colder kinematics of the gas from which they have formed. We also discuss the fingerprints of features attributed to TP-AGB stars in the spectra of the nuclear regions of nearby galaxies.

  6. Global Burned Area and Biomass Burning Emissions from Small Fires

    NASA Technical Reports Server (NTRS)

    Randerson, J. T.; Chen, Y.; vanderWerf, G. R.; Rogers, B. M.; Morton, D. C.

    2012-01-01

    In several biomes, including croplands, wooded savannas, and tropical forests, many small fires occur each year that are well below the detection limit of the current generation of global burned area products derived from moderate resolution surface reflectance imagery. Although these fires often generate thermal anomalies that can be detected by satellites, their contributions to burned area and carbon fluxes have not been systematically quantified across different regions and continents. Here we developed a preliminary method for combining 1-km thermal anomalies (active fires) and 500 m burned area observations from the Moderate Resolution Imaging Spectroradiometer (MODIS) to estimate the influence of these fires. In our approach, we calculated the number of active fires inside and outside of 500 m burn scars derived from reflectance data. We estimated small fire burned area by computing the difference normalized burn ratio (dNBR) for these two sets of active fires and then combining these observations with other information. In a final step, we used the Global Fire Emissions Database version 3 (GFED3) biogeochemical model to estimate the impact of these fires on biomass burning emissions. We found that the spatial distribution of active fires and 500 m burned areas were in close agreement in ecosystems that experience large fires, including savannas across southern Africa and Australia and boreal forests in North America and Eurasia. In other areas, however, we observed many active fires outside of burned area perimeters. Fire radiative power was lower for this class of active fires. Small fires substantially increased burned area in several continental-scale regions, including Equatorial Asia (157%), Central America (143%), and Southeast Asia (90%) during 2001-2010. Globally, accounting for small fires increased total burned area by approximately by 35%, from 345 Mha/yr to 464 Mha/yr. A formal quantification of uncertainties was not possible, but sensitivity

  7. Interpretation of Aura satellite observations of CO and aerosol index related to the December 2006 Australia fires

    NASA Astrophysics Data System (ADS)

    Luo, M.; Boxe, C.; Jiang, J.; Nassar, R.; Livesey, N.

    2009-11-01

    Enhanced Carbon Monoxide (CO) in the upper troposphere (UT) is shown by collocated Tropospheric Emission Spectrometer (TES) and Microwave Limb Sounder (MLS) measurements near and down-wind from the known wildfire region of SE Australia from 12-19 December 2006. Enhanced UV aerosol index (AI) derived from Ozone Monitoring Instrument (OMI) measurements correlate with these high CO concentrations. HYSPLIT model back trajectories trace selected air parcels to the SE Australia fire region as their initial location, where TES observes enhanced CO in the upper and lower troposphere. Simultaneously, they show a lack of vertical advection along their tracks. TES retrieved CO vertical profiles in the higher and lower southern latitudes are examined together with the averaging kernels and show that TES CO retrievals are most sensitive at approximately 300-400 hPa. The enhanced CO observed by TES at the upper (215 hPa) and lower (681 hPa) troposphere are, therefore, influenced by mid-tropospheric CO. GEOS-Chem model simulations with an 8-day emission inventory, as the wildfire source over Australia, are sampled to the TES/MLS observation times and locations. These simulations only show CO enhancements in the lower troposphere near and down-wind from the wildfire region of SE Australia with drastic underestimates of UT CO. Although CloudSat along-track ice-water content curtains are examined to see whether possible vertical convection events can explain the high UT CO values, sparse observations of collocated Aura CO and CloudSat along-track ice-water content measurements for the single event precludes any conclusive correlation. Vertical convection that uplift fire-induced CO (i.e. most notably referred to as pyro-cumulonimbus, pyroCb) may provide an explanation for the incongruence between these simulations and the TES/MLS observations of enhanced CO in the UT. Future GEOS-Chem simulations are needed to validate this conjecture as the the PyroCb mechanism is currently not

  8. Interpretation of Aura Satellite Observations of CO and Aerosol Index related to the December 2006 Australia Fires

    NASA Astrophysics Data System (ADS)

    Luo, M.; Boxe, C. S.; Jiang, J. H.; Nassar, R.; Logan, J. A.; Livesey, N. J.

    2009-12-01

    Enhanced Carbon Monoxide (CO) in the upper troposphere (UT) is shown by collocated Tropospheric Emission Spectrometer (TES) and Microwave Limb Sounder (MLS) measurements near and down-wind from the known wildfire region of SE Australia, December 12th-19th, 2006. Enhanced UV aerosol index (AI) derived from Ozone Monitoring Instrument (OMI) measurements correlate with these high CO concentrations. HYSPLIT model back trajectories trace selected air parcels to the SE Australia fire region from the initial locations with enhanced TES CO in the upper and lower troposphere. Simultaneously, they show a lack of vertical advection along their tracks. TES retrieved CO vertical profiles in the higher and lower southern latitudes are examined together with the averaging kernels and show that TES CO retrievals are most sensitive at approximately 300-400 hPa. The enhanced CO observed by TES at the upper (215 hPa) and lower (681 hPa) troposphere are therefore influenced by mid-tropospheric CO. GEOS-Chem model simulations with an 8-day emissions inventory as the wildfire source over Australia, are sampled to the TES/MLS observation times and locations. These simulations only show CO enhancements in the lower troposphere near and down-wind from the wildfire region of SE Australia with drastic underestimates of UT CO. Although CloudSat along-track ice-water content curtains are examined to see whether possible vertical convection events can explain the high UT CO values, sparse observations of collocated Aura CO and CloudSat along-track ice-water content measurements for the single event precludes any conclusive correlation. Vertical convection that uplift fire-induced CO (i.e., most notably referred to as pyro-cumulonimbus (pyroCb)) is likely responsible for the TES/MLS observations. The PyroCb mechanism is currently not incorporated in GEOS-Chem, thus providing a potential explanation for the incongruence between its simulations and TES/MLS observations of enhanced CO in the UT.

  9. Cannabinoid Receptor Activation Reverses Kainate-Induced Synchronized Population Burst Firing in Rat Hippocampus

    PubMed Central

    Mason, Rob; Cheer, Joseph F.

    2009-01-01

    Cannabinoids have been shown to possess anticonvulsant properties in whole animal models of epilepsy. The present investigation sought to examine the effects of cannabinoid receptor activation on kainic acid (KA)-induced epileptiform neuronal excitability. Under urethane anesthesia, acute KA treatment (10 mg kg−1, i.p.) entrained the spiking mode of simultaneously recorded neurons from random firing to synchronous bursting (% change in burst rate). Injection of the high-affinity cannabinoid agonist (-)-11-hydroxy-8-tetrahydrocannabinol-dimethyl-heptyl (HU210, 100 μg kg−1, i.p.) following KA markedly reduced the burst frequency (% decrease in burst frequency) and reversed synchronized firing patterns back to baseline levels. Pre-treatment with the central cannabinoid receptor (CB1) antagonist N-piperidino-5-(4-clorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-3-pyrazole-carboxamide (rimonabant, SR141716A 3 mg kg−1, i.p.) completely prevented the actions of HU210. The present results indicate that cannabinoids exert their antiepileptic effects by impeding pathological synchronization of neuronal networks in the hippocampus. PMID:19562087

  10. Effect of fire on soil microbial composition and activity in a Pinus canariensis forest and over time recovery

    NASA Astrophysics Data System (ADS)

    Ramírez Rojas, Irene; Fernández Lugo, Silvia; Arévalo Sierra, Jose Ramon; Pérez Fernández, María

    2016-04-01

    Wildfires are recurrent disturbances to forest ecosystems of Pinus canariensis, but their effects on soil microbial communities are not well characterized and have not previously been compared directly. Effects of fires on soil biotic properties are strongly dependent on the intensity of the fire, as well as on the type of soil and vegetation cover. This study aims at developing a comprehensive picture of the soil and vegetation dynamics to natural fries in an experiment comprising prescribed burning. The study was conducted at sites with similar soil, climatic, and other properties in a Canary pine forest in the Canary Islands, Spain. Soil microbial communities were assessed following four treatments: control, burnt soil the day after the fire, burnt soil three months after the fire and burnt soil six months after the. Burn treatments were conducted by the stuff from Cabildo de Canarias (Spain) on the 4th and 5th of June 2014. As a general rule, the organic carbon and the microbial biomass tend to decrease in the surface horizon after the fire, but the system responds increasing microbial activities and restoring soil variables in the subsequent months after the burning. Microbial biomass carbon significantly decreased in the burnt soils with their maximum negative effect immediately after the fire and during autumn, six months after the fire. Microbial biomass nitrogen also decreased in the burnt site immediately after the fire but increased in the following months, probably because of microbial assimilation of the increased amounts of available NH4+ and NO3- due to burning. Bacterial community composition was analyzed by metagenomics analyses Illumina showing strong variations amongst horizons and burning treatment both in total numbers and their composition. Changes in plant community were also monitored at the level of germination and plant recovery. Although fire negatively affects germination, seedling survival improves by increased growth rates of seedlings

  11. Impact of fire, landscape position, aspect, and soil depth on microbial extracellular enzyme activities in the Jemez River Basin Critical Zone Observatory.

    NASA Astrophysics Data System (ADS)

    Fairbanks, D.; Murphy, M. A.; Frost, G.; Chorover, J.; Gallery, R. E.; Rich, V. I.

    2014-12-01

    Fire frequency and severity are increasing across the western US, and post-fire recovery and effects on critical zone structure are not fully understood. Resident microbiota (bacteria and fungi) transform the majority of carbon in ecosystems, and the structure of these communities influence seedling establishment and the trajectory of vegetative recovery as well as biogeochemical cycling. We surveyed changes in microbial composition and activity after wildfire to better understand soil microbial resilience and fire ecology. Specifically, we assessed potential extracellular enzyme activities in response to fire severity across landscape position and aspect. We sampled 18 days after containment of the June 2013 Thompson Ridge Fire in the Jemez River Basin Critical Zone Observatory, across a gradient of burn severities in a mixed-conifer zero order basin. We subsampled six depths through the surface soil profile and measured potential activities of seven hydrolytic enzymes using established fluorometric techniques. Four of these enzymes hydrolyze C-rich substrates (β-glucosidase [BG], β-D-cellubiosidase [CB], xylosidase [XYL], and α-glucosidase [AG], two hydrolyze N-rich substrates N-acetyl-β-glucosaminidase [NAG] and leucine aminopeptidase [LAP]), and one hydrolyzes a P-rich substrate (acid phosphatase [PHOS]). Results showed decreased activities with depth for BG, CB, and LAP. Significantly higher potential enzyme activity was observed for convergent sites relative to planar or divergent sites across all depths sampled. Additionally, we looked at shifts in enzyme nutrient acquisition ratios that correspond with resource limitations relative to microbial stoichiometric demands. Higher acquisition potential is interpreted as greater resource allocation towards nutrient acquisition. Results showed a variance in resource acquisition potential with depth for C relative to N, with greater resources being allocated towards acquiring C at shallower depth. Conversely

  12. Forest fires in the insular Caribbean.

    PubMed

    Robbins, A Marcus J; Eckelmann, Claus-Martin; Quiñones, Maya

    2008-12-01

    This paper presents a summary of the forest fire reports in the insular Caribbean derived from both management reports and an analysis of publicly available Moderate Resolution Imaging Spectrodiometer (MODIS) satellite active fire products from the region. A vast difference between the amount of fires reported by land managers and fire points in the MODIS Fire Information for Resource Management System data can be observed. Future research is recommended to better understand the nature of these differences. While there is a general lack of available statistical data on forest fires in the Caribbean, a few general observations can be made: Forest fires occur mainly in dry forest types (500 to 1000 mm of mean annual rainfall). These are also the areas where most human settlements are located. Lowland high forests and montane forests with higher rainfall (1000 and more mm y(-1)) are less susceptible to forest fire, but they can burn in exceptionally dry years. Most of the dry forest ecosystems in the Caribbean can be considered to be fire-sensitive ecosystems, while the pine forests in the Caribbean (Cuba, Dominican Republic, and the Bahamas) are maintained by wildfires. In fire-sensitive ecosystems, uncontrolled burning often encourages the spread of alien invasive species. A Caribbean Fire Management Cooperation Strategy was developed between 2005 and 2006 under auspices of the Food and Agriculture Organization of the United Nations. This regional strategy aims to strengthen Caribbean fire management networking by encouraging closer collaboration among countries with similar ecological conditions. The strategy for the Caribbean identifies a number of research, training, and management activities to improve wildfire management capacity in the Caribbean.

  13. Effects of periplocoside X on midgut cells and digestive enzymes activity of the soldiers of red imported fire ant.

    PubMed

    Li, Yan; Zeng, Xin-Nian

    2013-07-01

    The pathological effects of ingested periplocoside X, an insecticidal component isolated from the root of Periploca sepium Bunge, on the midgut epithelial cells of the soldiers of red imported fire ant were studied and the symptom was described. The results showed that periplocoside X could induce a severe, time-dependent cytotoxicity in the midgut epithelial cells. An optical microscopy showed that epithelial cells swelled firstly and then lysed. Transmission electron microscopy (TEM) showed that numerous swollen lysosomes were appeared, microvilli were disrupted and sloughed off, and the numbers of the rough endoplasmic reticulum and the mitochondria decreased sharply in earlier stage. Numerous vacuoles were observed in the later stage. Finally, periplocoside X resulted in cell death by cytolysis. Assay of main three digestive enzymes activity indicated that amylase activity was significantly inhibited, but no significant changes were seen for lipase activity and total protease activity. So it is suggested that periplocoside X induced mainly to organic damage of midgut epithelium cells of insect. In all, insect midgut is one of targets for periplocoside X.

  14. High-frequency observations of signals and noise near RSON: implications for the discrimination of ripple-fired mining blasts

    SciTech Connect

    Smith, A.T.; Grose, R.D.

    1987-04-27

    Discrimination of large chemical explosions from possible clandestine nuclear tests is a significant issue for seismic verification. Unless discrimination is possible, the numerous mining blasts within the USSR would give ample opportunity for concealing a clandestine test. Evernden et al. (1986) advocate high frequencies as a means to detect these clandestine tests; however, mining blasts must still give a unique signature for their discrimination. Specific conditions are also necessary for high-frequency verification: low attenuation and quiet seismic stations are among the most important. In this study we address these problems under conditions representing a best case scenerio. During the summer of 1985, LLNL deployed a regional array and high-frequency station near RSON (Red Lake, Ontario, Canada) to study regional seismic signals at a low-noise site with excellent propagation characteristics, the continental shield. One objective was to evaluate the performance of regional seismic arrays and high-frequency stations in this geological environment. Using high-frequency data from mining blasts within the Masabi Iron Range in northern Minnesota (distance of 400 km), we observed the high-frequency P/sub n/ phase of ripple-fired blasts, modelled their source properties, and evaluated a possible discriminant for chemical explosions. This study suggests the existence of a distinctive signature for large chemical explosions: strong, high-frequency spectral peaks in the P spectra introduced by delay shooting or ripple-firing. Its application depends, however, on a frequency band extending to at least 35 Hz at regional distances and predictably quiet seismic sites.

  15. Advanced Fire Information System - A real time fire information system for Africa

    NASA Astrophysics Data System (ADS)

    Frost, P. E.; Roy, D. P.

    2012-12-01

    The Council for Scientific and Industrial Research (CSIR) lead by the Meraka Institute and supported by the South African National Space Agency (SANSA) developed the Advanced Fire Information System (AFIS) to provide near real time fire information to a variety of operational and science fire users including disaster managers, fire fighters, farmers and forest managers located across Southern and Eastern Africa. The AFIS combines satellite data with ground based observations and statistics and distributes the information via mobile phone technology. The system was launched in 2004, and Eskom (South Africa' and Africa's largest power utility) quickly became the biggest user and today more than 300 Eskom line managers and support staff receive cell phone and email fire alert messages whenever a wildfire is within 2km of any of the 28 000km of Eskom electricity transmission lines. The AFIS uses Earth observation satellites from NASA and Europe to detect possible actively burning fires and their fire radiative power (FRP). The polar orbiting MODIS Terra and Aqua satellites provide data at around 10am, 15pm, 22am and 3am daily, while the European Geostationary MSG satellite provides 15 minute updates at lower spatial resolution. The AFIS processing system ingests the raw satellite data and within minutes of the satellite overpass generates fire location and FRP based fire intensity information. The AFIS and new functionality are presented including an incident report and permiting system that can be used to differentiate between prescribed burns and uncontrolled wild fires, and the provision of other information including 5-day fire danger forecasts, vegetation curing information and historical burned area maps. A new AFIS mobile application for IOS and Android devices as well as a fire reporting tool are showcased that enable both the dissemination and alerting of fire information and enable user upload of geo tagged photographs and on the fly creation of fire reports

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

    DOE PAGES

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

    2015-02-13

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

  17. Differential modulation of repetitive firing and synchronous network activity in neocortical interneurons by inhibition of A-type K+ channels and Ih

    PubMed Central

    Williams, Sidney B.; Hablitz, John J.

    2015-01-01

    GABAergic interneurons provide the main source of inhibition in the neocortex and are important in regulating neocortical network activity. In the presence 4-aminopyridine (4-AP), CNQX, and D-APV, large amplitude GABAA-receptor mediated depolarizing responses were observed in the neocortex. GABAergic networks are comprised of several types of interneurons, each with its own protein expression pattern, firing properties, and inhibitory role in network activity. Voltage-gated ion channels, especially A-type K+ channels, differentially regulate passive membrane properties, action potential (AP) waveform, and repetitive firing properties in interneurons depending on their composition and localization. HCN channels are known modulators of pyramidal cell intrinsic excitability and excitatory network activity. Little information is available regarding how HCN channels functionally modulate excitability of individual interneurons and inhibitory networks. In this study, we examined the effect of 4-AP on intrinsic excitability of fast-spiking basket cells (FS-BCs) and Martinotti cells (MCs). 4-AP increased the duration of APs in both FS-BCs and MCs. The repetitive firing properties of MCs were differentially affected compared to FS-BCs. We also examined the effect of Ih inhibition on synchronous GABAergic depolarizations and synaptic integration of depolarizing IPSPs. ZD 7288 enhanced the amplitude and area of evoked GABAergic responses in both cell types. Similarly, the frequency and area of spontaneous GABAergic depolarizations in both FS-BCs and MCs were increased in presence of ZD 7288. Synaptic integration of IPSPs in MCs was significantly enhanced, but remained unaltered in FS-BCs. These results indicate that 4-AP differentially alters the firing properties of interneurons, suggesting MCs and FS-BCs may have unique roles in GABAergic network synchronization. Enhancement of GABAergic network synchronization by ZD 7288 suggests that HCN channels attenuate inhibitory

  18. Fire parameterization on a global scale

    NASA Astrophysics Data System (ADS)

    Pechony, O.; Shindell, D. T.

    2009-08-01

    We present a convenient physically based global-scale fire parameterization algorithm for global climate models. We indicate environmental conditions favorable for fire occurrence based on calculation of the vapor pressure deficit as a function of location and time. Two ignition models are used. One assumes ubiquitous ignition, the other incorporates natural and anthropogenic sources, as well as anthropogenic fire suppression. Evaluation of the method using Global Precipitation Climatology Project precipitation, National Centers for Environmental Prediction/National Center for Atmospheric Research temperature and relative humidity, and Moderate Resolution Imaging Spectroradiometer (MODIS) Leaf Area Index as a proxy for global vegetation density gives results in remarkable correspondence with global fire patterns observed from the MODIS and Visible and Infrared Scanner satellite instruments. The parameterized fires successfully reproduce the spatial distribution of global fires as well as the seasonal variability. The interannual variability of global fire activity derived from the 20-year advanced very high resolution radiometer record are well reproduced using Goddard Institute for Space Studies general circulation models climate simulations, as is the response to the climate changes following the eruptions of El Chichon and Mount Pinatubo. In conjunction with climate models and data sets on vegetation changes with time, the suggested fire parameterization offers the possibility to estimate relative variations of global fire activity for past and future climates.

  19. Drivers of recent trends in African landscape fires

    NASA Astrophysics Data System (ADS)

    Andela, Niels; van der Werf, Guido R.

    2014-05-01

    Wildfires play an important role in savannah ecosystem dynamics and are an important source of emissions of (greenhouse) gasses and aerosols. Africa is nowadays responsible for about 70% of global burned area and about 50% of fire carbon emissions. Although it has been reported that fire activity varies according to climatic and anthropogenic influences, much remains unclear about the drivers of the spatial distribution of fire activity over the continent and its temporal dynamics. Resolving the drivers of this spatiotemporal variability is crucial to understand the future role of fire on the African continent. Satellite observations are the preferred way to monitor fire activity at this scale and the satellite fire record starts to be long enough to study recent trends in fire occurrence, the subject of our work. We developed a model to account for variations in fire activity due to climate, and investigated the role of sea surface temperatures on rainfall patterns and thus fire dynamics. Spatial variation and trends in land cover were used to improve understanding of underlying trends caused by socio-economic changes. Results elucidate the importance of various drivers on recent trends in African landscape fires and allow new insights in the future of African fire dynamics.

  20. Impact and Recovery Pattern of a Spring Fire on a Pacific Coast Marsh - Observations and Implications for Endangered Species

    NASA Astrophysics Data System (ADS)

    Brown, L. N.; Willis, K. S.; Ambrose, R. F.; MacDonald, G. M.

    2015-12-01

    The flammability of California coastal marsh vegetation is highest in winter and spring when dominant high marsh plants such as Sarcocornia pacifica are dormant. With climate change the number of cool-season fires are increasing in the state, and marsh systems are becoming more vulnerable to fire disturbance. Very little information exists in peer-reviewed or grey literature on the presence of fire in Pacific Coast tidal marshes. In 1993, the Green Meadows fire in Ventura County, California burned a small portion of tidally influenced Sarcocornia­-dominated marsh at Point Mugu. After the May 2013 Springs Fire burned a similar portion of the salt marsh vegetation, we conducted a two-year vegetation recovery survey using transects of surface vegetation plots and MODIS derived NDVI remote sensing monitoring. Recovery during the first year was limited. Sixteen months into the recovery period, percent plant coverage reached an average of approximately 60% for all plots in the burned area, as opposed to an average of 100% in control plots, and remained at that level for the duration of the study. NDVI did not approach near pre-fire conditions until 19 months after the fire. While recovery may have been influenced by California's current extreme drought conditions, the recurrence of fire and rate of recovery raise many important questions as to the role of fire in Pacific coast tidal marshes. For example, the lack of Salicornia cover over more than an entire breeding season would be detrimental to protected species such as Rallus obsoletus. Fire adds new vulnerabilities on critical tidal marsh habitat already taxed by the threat of sea-level rise, coastal squeeze and invasive species.

  1. Fire as Technology

    ERIC Educational Resources Information Center

    Rudolph, Robert N.

    2011-01-01

    In this article, the author describes a project that deals with fire production as an aspect of technology. The project challenges students to be survivors in a five-day classroom activity. Students research various materials and methods to produce fire without the use of matches or other modern combustion devices, then must create "fire" to keep…

  2. Evaluation of Biogenic and Fire Emissions in a Global Chemistry Model with NOMADSS, DC3 and SEAC4RS observations

    NASA Astrophysics Data System (ADS)

    Emmons, L. K.; Wiedinmyer, C.; Park, M.; Kaser, L.; Apel, E. C.; Guenther, A. B.

    2014-12-01

    Numerous measurements of compounds produced by biogenic and fire emissions were made during several recent field campaigns in the southeast United States, providing a unique data set for emissions and chemical model evaluation. The NCAR Community Atmosphere Model with Chemistry (CAM-chem) is coupled to the Community Land Model (CLM), which includes the biogenic emissions model MEGAN-v2.1, allowing for online calculation of emissions from vegetation for 150 compounds. Simulations of CAM-chem for summers 2012 and 2013 are evaluated with the aircraft and ground-based observations from DC3, NOMADSS and SEAC4RS. Comparison of directly emitted biogenic species, such as isoprene, terpenes, methanol and acetone, are used to evaluate the MEGAN emissions. Evaluation of oxidation products, including methyl vinyl ketone (MVK), methacrolein, formaldehyde, and other oxygenated VOCs are used to test the model chemistry mechanism. In addition, several biomass burning inventories are used in the model, including FINN, QFED, and FLAMBE, and are compared for their impact on atmospheric composition and ozone production, and evaluated with the aircraft observations.

  3. Glial potassium channels activated by neuronal firing or intracellular cyclic AMP in Helix.

    PubMed

    Gommerat, I; Gola, M

    1996-09-15

    1. Cell-attached and whole cell patch clamp experiments were performed on satellite glial cells adhering to the cell body of neurones in situ within the nervous system of the snail Helix pomatia. The underlying neurone was under current or voltage-clamp control. 2. Neuronal firing induced a delayed (20-30 s) persistent (3-4 min) increase in the opening probability of glial K+ channels. The channels were also activated by perfusing the ganglion with a depolarizing high-K+ saline, except when the underlying neurone was prevented from depolarizing under voltage-clamp conditions. 3. Two K(+)-selective channels were detected in the glial membrane. The channel responding to neuronal firing was present in 95% of the patches (n = 393). It had a unitary conductance of 56 pS, a Na+ :K+ permeability ratio < 0.02 and displayed slight inward rectification in symmetrical [K+] conditions. It was sensitive to TEA, Ba2+ and Cs+. The following results refer to this channel as studied in the cell-attached configuration. 4. The glial K+ channel was activated by bath application of the membrane-permeant cyclic AMP derivatives 8-bromo-cAMP and dibutyryl-cAMP, the adenylyl cyclase activator forskolin and the diesterase inhibitors IBMX, theophylline and caffeine. It was insensitive to cyclic GMP activators and to conditions that might alter the intracellular [Ca2+] (ionomycin, low-Ca2+ saline and Ca2+ channel blockers). 5. The forskolin-induced changes in channel behaviour (open and closed time distributions, burst duration, short and long gaps within bursts) could be accounted for by a four-state model (3 closed states, 1 open state) by simply changing one of the six rate parameters. 6. The present results suggest that the signal sent by an active neurone to satellite glial cells is confined to the glial cells round that neurone. The effect of this signal on the class of glial K+ channels studied can be mimicked by an increase in glial cAMP concentration. The subsequent delayed opening

  4. Glial potassium channels activated by neuronal firing or intracellular cyclic AMP in Helix.

    PubMed Central

    Gommerat, I; Gola, M

    1996-01-01

    1. Cell-attached and whole cell patch clamp experiments were performed on satellite glial cells adhering to the cell body of neurones in situ within the nervous system of the snail Helix pomatia. The underlying neurone was under current or voltage-clamp control. 2. Neuronal firing induced a delayed (20-30 s) persistent (3-4 min) increase in the opening probability of glial K+ channels. The channels were also activated by perfusing the ganglion with a depolarizing high-K+ saline, except when the underlying neurone was prevented from depolarizing under voltage-clamp conditions. 3. Two K(+)-selective channels were detected in the glial membrane. The channel responding to neuronal firing was present in 95% of the patches (n = 393). It had a unitary conductance of 56 pS, a Na+ :K+ permeability ratio < 0.02 and displayed slight inward rectification in symmetrical [K+] conditions. It was sensitive to TEA, Ba2+ and Cs+. The following results refer to this channel as studied in the cell-attached configuration. 4. The glial K+ channel was activated by bath application of the membrane-permeant cyclic AMP derivatives 8-bromo-cAMP and dibutyryl-cAMP, the adenylyl cyclase activator forskolin and the diesterase inhibitors IBMX, theophylline and caffeine. It was insensitive to cyclic GMP activators and to conditions that might alter the intracellular [Ca2+] (ionomycin, low-Ca2+ saline and Ca2+ channel blockers). 5. The forskolin-induced changes in channel behaviour (open and closed time distributions, burst duration, short and long gaps within bursts) could be accounted for by a four-state model (3 closed states, 1 open state) by simply changing one of the six rate parameters. 6. The present results suggest that the signal sent by an active neurone to satellite glial cells is confined to the glial cells round that neurone. The effect of this signal on the class of glial K+ channels studied can be mimicked by an increase in glial cAMP concentration. The subsequent delayed opening

  5. [The "Mining Rescue System and Mine Fires" Working Group. Tasks, results, future activities].

    PubMed

    Coenders, A

    1983-01-01

    The president of the working party presents details of its principal tasks in the past and in the present time. These can be summed up in a study of the problems mentioned below and the subsequent elaboration of recommendations for the benefit of the governments, guidelines, information reports and research proposals. The principal problems that were or are still under study are: --prevention of fires: shaft equipment, hydraulic fluids, belt conveyors, . . .; --detection of mine fires and spontaneous combustion; --fighting of mine fires: shaft fires, construction of stoppings, openings and recovering of fire zones, . . .; --coordination and rescue equipment: escape and rescue breathing apparatus, flameproof clothing, rescue of trapped miners; --stabilization of ventilation in the event of fire, . . . The speaker stresses the importance of the information exchange and the atmosphere of fellowship and solidarity that prevails in the working party.

  6. Miscellaneous observations of active galactic nuclei. II.

    NASA Astrophysics Data System (ADS)

    Goncalves, A. C.; Veron, P.; Veron-Cetty, M.-P.

    1998-01-01

    We observed 37 AGN candidates and classified them on the basis of their spectroscopic properties; three are confirmed QSOs, one is a BL Lac object, nine are Seyfert 1 galaxies, four Seyfert 2s, while twenty are HII regions. Based on observations collected at the Observatoire de Haute-Provence (CNRS), France, and at the European Southern Observatory, La Silla, Chili.

  7. Work activities and the onset of first-time low back pain among New York City fire fighters.

    PubMed

    Nuwayhid, I A; Stewart, W; Johnson, J V

    1993-03-01

    In a prospective study of first-time low back pain among New York City fire fighters, a total of 115 cases and 109 randomly selected controls were interviewed by telephone between December 1988 and July 1989 to examine the role of recent work activities in the onset of first-time low back pain. After adjusting for known risk factors and off-duty activities, statistically significant high-risk work activities included operating a charged hose inside a building (odds ratio (OR) = 3.26), climbing ladders (OR = 3.18), breaking windows (OR = 4.45), cutting structures (OR = 6.47), looking for hidden fires (OR = 4.32), and lifting objects > or = 18 kg (OR = 3.07). Low-risk activities included connecting hydrants to pumpers (OR = 0.36), pulling booster hose (OR = 0.19), and participating in drills (OR = 0.09) or physical training (OR = 0.16). When further adjusted for exposure to smoke (OR = 13.59), a surrogate for severity of alarms, the ORs associated with high-risk activities were no longer significant. This, however, does not diminish the role of activities in the onset of low back pain. Instead, it suggests an inseparable role for activities and environmental hazards. To examine this, the risk of low back pain was measured within five work zones sequential in time relative to location and distance from a structural fire. The risk gradually increased as the fire fighter moved away from the firehouse (OR = 0.10) and closer to the site of fire (OR = 3.91).

  8. Microvariability Observations of Three Active Galactic Nuclei

    NASA Astrophysics Data System (ADS)

    Clements, S. D.; Hirschmann, A.; Jenks, A.; Keshishian, G.; Torres, Y.

    2000-12-01

    Microvariability observations are presented for three objects - the BL Lac object OQ 530, the OVV quasar 3CR 345, and the very high redshift quasar PSS 1057+4555. All objects were observed using the 0.76m telescope at the Rosemary Hill Observatory. The object OQ 530 was observed in the R band during three nights in June of 1997. Observations in the V and I bands were made of the OVV quasar 3CR 345 in May of 2000. The microvariability behavior reported here for OQ 530 and 3CR 345 is compared to the previously reported behavior for these objects. In addition, observations were carried out over four nights in March and May of 2000 to search for microvariability of the very high redshift (z = 4.10) quasar PSS 1057+4555. The data presented here for these three objects are discussed in relation to current models for microvariability.

  9. Long-term deforestation in NW Spain: linking the Holocene fire history to vegetation change and human activities

    NASA Astrophysics Data System (ADS)

    Kaal, Joeri; Carrión Marco, Yolanda; Asouti, Eleni; Martín Seijo, Maria; Martínez Cortizas, Antonio; Costa Casáis, Manuela; Criado Boado, Felipe

    2011-01-01

    The Holocene fire regime is thought to have had a key role in deforestation and shrubland expansion in Galicia (NW Spain) but the contribution of past societies to vegetation burning remains poorly understood. This may be, in part, due to the fact that detailed fire records from areas in close proximity to archaeological sites are scarce. To fill this gap, we performed charcoal analysis in five colluvial soils from an archaeological area (Campo Lameiro) and compared the results to earlier studies from this area and palaeo-ecological literature from NW Spain. This analysis allowed for the reconstruction of the vegetation and fire dynamics in the area during the last ca 11 000 yrs. In the Early Holocene, Fabaceae and Betula sp. were dominant in the charcoal record. Quercus sp. started to replace these species around 10 000 cal BP, forming a deciduous forest that prevailed during the Holocene Thermal Maximum until ˜5500 cal BP. Following that, several cycles of potentially fire-induced forest regression with subsequent incomplete recovery eventually led to the formation of an open landscape dominated by shrubs (Erica sp. and Fabaceae). Major episodes of forest regression were (1) ˜5500-5000 cal BP, which marks the mid-Holocene cooling after the Holocene Thermal Maximum, but also the period during which agropastoral activities in NW Spain became widespread, and (2) ˜2000-1500 cal BP, which corresponds roughly to the end of the Roman Warm Period and the transition from the Roman to the Germanic period. The low degree of chronological precision, which is inherent in fire history reconstructions from colluvial soils, made it impossible to distinguish climatic from human-induced fires. Nonetheless, the abundance of synanthropic pollen indicators (e.g. Plantago lanceolata and Urtica dioica) since at least ˜6000 cal BP strongly suggests that humans used fire to generate and maintain pasture.

  10. Activation of nicotinic acetylcholine receptors enhances a slow calcium-dependent potassium conductance and reduces the firing of stratum oriens interneurons.

    PubMed

    Griguoli, Marilena; Scuri, Rossana; Ragozzino, Davide; Cherubini, Enrico

    2009-09-01

    A large variety of distinct locally connected GABAergic cells are present in the hippocampus. By releasing GABA into principal cells and interneurons, they exert a powerful control on neuronal excitability and are responsible for network oscillations crucial for information processing in the brain. Here, whole-cell patch clamp recordings in current and voltage clamp mode were used to study the functional role of nicotinic acetylcholine receptors (nAChRs) on the firing properties of stratum oriens interneurons in hippocampal slices from transgenic mice expressing enhanced green fluorescent protein in a subpopulation of GABAergic cells containing somatostatin (GIN mice). Unexpectedly, activation of nAChRs by nicotine or endogenously released acetylcholine strongly enhanced spike frequency adaptation. This effect was blocked by apamin, suggesting the involvement of small calcium-dependent potassium channels (SK channels). Nicotine-induced reduction in firing frequency was dependent on intracellular calcium rise through calcium-permeable nAChRs and voltage-dependent calcium channels activated by the depolarizing action of nicotine. Calcium imaging experiments directly showed that nicotine effects on firing rate were correlated with large increases in intracellular calcium. Furthermore, blocking ryanodine receptors with ryanodine or sarcoplasmic-endoplasmic reticulum calcium ATPase with thapsygargin or cyclopiazonic acid fully prevented the effects of nicotine, suggesting that mobilization of calcium from the internal stores contributed to the observed effects. By regulating cell firing, cholinergic signalling through nAChRs would be instrumental for fine-tuning the output of stratum oriens interneurons and correlated activity at the network level.

  11. Analytically tractable studies of traveling waves of activity in integrate-and-fire neural networks.

    PubMed

    Zhang, Jie; Osan, Remus

    2016-05-01

    In contrast to other large-scale network models for propagation of electrical activity in neural tissue that have no analytical solutions for their dynamics, we show that for a specific class of integrate and fire neural networks the acceleration depends quadratically on the instantaneous speed of the activity propagation. We use this property to analytically compute the network spike dynamics and to highlight the emergence of a natural time scale for the evolution of the traveling waves. These results allow us to examine other applications of this model such as the effect that a nonconductive gap of tissue has on further activity propagation. Furthermore we show that activity propagation also depends on local conditions for other more general connectivity functions, by converting the evolution equations for network dynamics into a low-dimensional system of ordinary differential equations. This approach greatly enhances our intuition into the mechanisms of the traveling waves evolution and significantly reduces the simulation time for this class of models.

  12. Analytically tractable studies of traveling waves of activity in integrate-and-fire neural networks

    NASA Astrophysics Data System (ADS)

    Zhang, Jie; Osan, Remus

    2016-05-01

    In contrast to other large-scale network models for propagation of electrical activity in neural tissue that have no analytical solutions for their dynamics, we show that for a specific class of integrate and fire neural networks the acceleration depends quadratically on the instantaneous speed of the activity propagation. We use this property to analytically compute the network spike dynamics and to highlight the emergence of a natural time scale for the evolution of the traveling waves. These results allow us to examine other applications of this model such as the effect that a nonconductive gap of tissue has on further activity propagation. Furthermore we show that activity propagation also depends on local conditions for other more general connectivity functions, by converting the evolution equations for network dynamics into a low-dimensional system of ordinary differential equations. This approach greatly enhances our intuition into the mechanisms of the traveling waves evolution and significantly reduces the simulation time for this class of models.

  13. Activity patterns and parasitism rates of fire ant decapitating flies (Diptera:Phoridae:Pseudacteon spp.) in their native Argentina

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Technical Abstract: This work describes the annual and daily activity patterns of two parasitoid fly communities of the fire ant S. invicta (Hymenoptera: Formicidae) in their native Argentina. Pseudacteon (Diptera: Phoridae) flies were censused monthly for one year at two sites in northwestern Corr...

  14. Advanced fire-resistant forms of activated carbon and methods of adsorbing and separating gases using same

    SciTech Connect

    Xiong, Yongliang; Wang, Yifeng

    2015-02-03

    Advanced, fire-resistant activated carbon compositions useful in adsorbing gases; and having vastly improved fire resistance are provided, and methods for synthesizing the compositions are also provided. The advanced compositions have high gas adsorption capacities and rapid adsorption kinetics (comparable to commercially-available activated carbon), without having any intrinsic fire hazard. They also have superior performance to Mordenites in both adsorption capacities and kinetics. In addition, the advanced compositions do not pose the fibrous inhalation hazard that exists with use of Mordenites. The fire-resistant compositions combine activated carbon mixed with one or more hydrated and/or carbonate-containing minerals that release H.sub.2O and/or CO.sub.2 when heated. This effect raises the spontaneous ignition temperature to over 500.degree. C. in most examples, and over 800.degree. C. in some examples. Also provided are methods for removing and/or separating target gases, such as Krypton or Argon, from a gas stream by using such advanced activated carbons.

  15. High firing rate of neonatal hippocampal interneurons is caused by attenuation of afterhyperpolarizing potassium currents by tonically active kainate receptors.

    PubMed

    Segerstråle, Mikael; Juuri, Juuso; Lanore, Frédéric; Piepponen, Petteri; Lauri, Sari E; Mulle, Christophe; Taira, Tomi

    2010-05-12

    In the neonatal hippocampus, the activity of interneurons shapes early network bursts that are important for the establishment of neuronal connectivity. However, mechanisms controlling the firing of immature interneurons remain elusive. We now show that the spontaneous firing rate of CA3 stratum lucidum interneurons markedly decreases during early postnatal development because of changes in the properties of GluK1 (formerly known as GluR5) subunit-containing kainate receptors (KARs). In the neonate, activation of KARs by ambient glutamate exerts a tonic inhibition of the medium-duration afterhyperpolarization (mAHP) by a G-protein-dependent mechanism, permitting a high interneuronal firing rate. During development, the amplitude of the apamine-sensitive K+ currents responsible for the mAHP increases dramatically because of decoupling between KAR activation and mAHP modulation, leading to decreased interneuronal firing. The developmental shift in the KAR function and its consequences on interneuronal activity are likely to have a fundamental role in the maturation of the synchronous neuronal oscillations typical for adult hippocampal circuitry.

  16. Fire and ice: GRaND observations of Vesta and Ceres by Dawn

    NASA Astrophysics Data System (ADS)

    Prettyman, Thomas H.; Yamashita, Naoyuki; Toplis, Michael J.; Y McSween, Harry; Schorghofer, Norbert; Marchi, Simone; Feldman, William C.; Castillo-Rogez, Julie; Raymond, Carol; Russell, Christopher T.; Dawn Science Team

    2016-10-01

    In June of 2016, Dawn completed its primary mission to explore the asteroid (4) Vesta and the dwarf planet (1) Ceres, the largest bodies in the main belt. At both targets, Dawn's Gamma Ray and Neutron Detector (GRaND) acquired several months of global elemental mapping data. Gamma ray and neutron spectra were analyzed to determine the bulk elemental composition of the uppermost meter of the regolith within broad surface regions. Measurements of global Fe/Si, Fe/O, and K/Th ratios buttress the connection between Vesta and the Howardite, Eucrite and Diogenite (HED) meteorites. Their parent body underwent igneous differentiation to form an iron-rich core, ultramafic mantle, and basaltic crust. In some regions, GRaND measurements show that hydrogen is concentrated in Vesta's otherwise anhydrous, basaltic regolith. Multiple lines of evidence support exogenic delivery of hydrogen by the infall of carbonaceous chondrites. In comparison, the regolith of Ceres contains orders of magnitude more hydrogen, which must have originated from within. Near Ceres' equator, the elemental composition of the regolith resembles the aqueously altered CI/CM chondrites (based on H, Fe, K, C and compositional parameters). Increased concentrations of hydrogen observed by GRaND at high latitudes likely result from the presence of extensive near-surface water ice, as anticipated by Fanale and Salvail (1989). GRaND data provide evidence that the action of water altered Ceres on a global scale, resulting in widespread hydrated minerals and residual water ice that has survived to the present day. We describe how GRaND elemental measurements constrain chemical and physical processes that shaped Ceres and discuss implications for the origins of Ceres and similar main belt objects.Fanale, F. P. and J. R. Salvail (1989), The water regime of asteroid (1) Ceres, Icarus, Vol. 82, Issue 1, pp. 97-110, doi:10.1016/0019-1035(89)90026-2.

  17. How wild is your model fire? Constraining WRF-Chem wildfire smoke simulations with satellite observations

    NASA Astrophysics Data System (ADS)

    Fischer, E. V.; Ford, B.; Lassman, W.; Pierce, J. R.; Pfister, G.; Volckens, J.; Magzamen, S.; Gan, R.

    2015-12-01

    Exposure to high concentrations of particulate matter (PM) present during acute pollution events is associated with adverse health effects. While many anthropogenic pollution sources are regulated in the United States, emissions from wildfires are difficult to characterize and control. With wildfire frequency and intensity in the western U.S. projected to increase, it is important to more precisely determine the effect that wildfire emissions have on human health, and whether improved forecasts of these air pollution events can mitigate the health risks associated with wildfires. One of the challenges associated with determining health risks associated with wildfire emissions is that the low spatial resolution of surface monitors means that surface measurements may not be representative of a population's exposure, due to steep concentration gradients. To obtain better estimates of ambient exposure levels for health studies, a chemical transport model (CTM) can be used to simulate the evolution of a wildfire plume as it travels over populated regions downwind. Improving the performance of a CTM would allow the development of a new forecasting framework that could better help decision makers estimate and potentially mitigate future health impacts. We use the Weather Research and Forecasting model with online chemistry (WRF-Chem) to simulate wildfire plume evolution. By varying the model resolution, meteorology reanalysis initial conditions, and biomass burning inventories, we are able to explore the sensitivity of model simulations to these various parameters. Satellite observations are used first to evaluate model skill, and then to constrain the model results. These data are then used to estimate population-level exposure, with the aim of better characterizing the effects that wildfire emissions have on human health.

  18. A novel active fire protection approach for structural steel members using NiTi shape memory alloy

    NASA Astrophysics Data System (ADS)

    Sadiq, H.; Wong, M. B.; Al-Mahaidi, R.; Zhao, X. L.

    2013-02-01

    A novel active fire protection approach, based on integrating a shape memory alloy, NiTi, with a steel structure, was proposed to satisfy the fire resistance requirements in structural design. To demonstrate the principles of this approach, a simple structure in the form of a simply supported steel beam was used. The internal action of the beam due to a transverse applied load was reduced by utilizing the shape memory effect in the NiTi alloy at rising temperatures. As a result, the net internal action from the load design was kept below the deteriorated load capacity of the beam during the fire scenario for period of time that was longer than that of the original beam without the NiTi alloy. By integrating the NiTi alloy into the beam system, the structure remained stable even though the steel temperature exceeded the critical temperature which may have caused the original beam structure to collapse. Prior to testing the composite NiTi-steel beam under simulated fire conditions, the NiTi alloy specimens were characterized at high temperatures. At 300 °C, the stiffness of the specimens increased by three times and its strength by four times over that at room temperature. The results obtained from the high-temperature characterization highlighted the great potential of the alloy being used in fire engineering applications.

  19. Frequency requirements for active earth observation sensors

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The foundation and rationale for the selection of microwave frequencies for active remote sensing usage and for subsequent use in determination of sharing criteria and allocation strategies for the WARC-79 are presented.

  20. Impact of antecedent climate on fire regimes in coastal California

    USGS Publications Warehouse

    Keeley, J.E.

    2004-01-01

    Severe fire weather is a major determinant of fire size in coastal California; however, it is unclear to what extent antecedent climate also controls fire activity. This study investigates the relationship between fire activity and climate in central coastal and southern California. Climate variables included the Palmer Drought Severity Index (PDSI), total monthly precipitation, mean monthly maximum temperature and the autumn and winter Southern Oscillation Indices (SOI). For both the central coast and the south coast regions there was no significant relationship between growing season PDSI, precipitation or temperature and number of fires. When examined by season, summer temperatures were positively correlated with number of fires in the central coast and autumn PDSI and precipitation were negatively correlated with fire occurrence in the south coast region. Area burned was not correlated with any current year climate variables in southern California although, in the central coast, drought during spring and autumn were correlated, but explained less than 10% of the variation in the area burned. Although there was a modest relationship between the Southern Oscillation Index (SOI) and local climate parameters, there was only a relatively weak relationship with fire activity. The importance of autumn foehn winds is illustrated by the observation that large fires occur most commonly during the autumn, regardless of PDSI. Antecedent climate, however, does appear to play some role in determining the length of the fire season on these landscape as PDSI is consistently related to the occurrence of large fires that occur before or after the autumn months.

  1. OBSERVING CORONAL NANOFLARES IN ACTIVE REGION MOSS

    SciTech Connect

    Testa, Paola; DeLuca, Ed; Golub, Leon; Korreck, Kelly; Weber, Mark; De Pontieu, Bart; Martinez-Sykora, Juan; Title, Alan; Hansteen, Viggo; Cirtain, Jonathan; Winebarger, Amy; Kobayashi, Ken; Kuzin, Sergey; Walsh, Robert; DeForest, Craig

    2013-06-10

    The High-resolution Coronal Imager (Hi-C) has provided Fe XII 193A images of the upper transition region moss at an unprecedented spatial ({approx}0.''3-0.''4) and temporal (5.5 s) resolution. The Hi-C observations show in some moss regions variability on timescales down to {approx}15 s, significantly shorter than the minute-scale variability typically found in previous observations of moss, therefore challenging the conclusion of moss being heated in a mostly steady manner. These rapid variability moss regions are located at the footpoints of bright hot coronal loops observed by the Solar Dynamics Observatory/Atmospheric Imaging Assembly in the 94 A channel, and by the Hinode/X-Ray Telescope. The configuration of these loops is highly dynamic, and suggestive of slipping reconnection. We interpret these events as signatures of heating events associated with reconnection occurring in the overlying hot coronal loops, i.e., coronal nanoflares. We estimate the order of magnitude of the energy in these events to be of at least a few 10{sup 23} erg, also supporting the nanoflare scenario. These Hi-C observations suggest that future observations at comparable high spatial and temporal resolution, with more extensive temperature coverage, are required to determine the exact characteristics of the heating mechanism(s).

  2. Sciencing with Mother Goose: Observation Activities with Chicken Little.

    ERIC Educational Resources Information Center

    Angus, Carolyn

    1996-01-01

    Provides sample observation activities to accompany the nursery tale of Chicken Little. Includes five activities that involve the skills of observing, communicating, comparing, ordering, and categorizing to engage students in hands-on science. (DDR)

  3. Evaluation of activated carbon for control of mercury from coal-fired boilers

    SciTech Connect

    Miller, S.; Laudal, D.; Dunham, G.

    1995-11-01

    The ability to remove mercury from power plant flue gas may become important because of the Clean Air Act amendments` requirement that the U.S. Environmental Protection Agency (EPA) assess the health risks associated with these emissions. One approach for mercury removal, which may be relatively simple to retrofit, is the injection of sorbents, such as activated carbon, upstream of existing particulate control devices. Activated carbon has been reported to capture mercury when injected into flue gas upstream of a spray dryer baghouse system applied to waste incinerators or coal-fired boilers. However, the mercury capture ability of activated carbon injected upstream of an electrostatic precipitator (ESP) or baghouse operated at temperatures between 200{degrees} and 400{degrees}F is not well known. A study sponsored by the U.S. Department of Energy and the Electric power Research Institute is being conducted at the University of North Dakota Energy & Environmental Research Center (EERC) to evaluate whether mercury control with sorbents can be a cost-effective approach for large power plants. Initial results from the study were reported last year. This paper presents some of the recent project results. Variables of interest include coal type, sorbent type, sorbent addition rate, collection media, and temperature.

  4. Activity of bifenthrin, chlorfenapyr, fipronil, and thiamethoxam against red imported fire ants (Hymenoptera: Formicidae).

    PubMed

    Wiltz, B A; Suiter, D R; Gardner, W A

    2010-06-01

    Bifenthrin, chlorfenapyr, fipronil, and thiamethoxam were evaluated for activity against the red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae). Mobility impairment and lethal times were determined after topical treatments. Both immobilization and mortality occurred most quickly with bifenthrin, followed by thiamethoxam, chlorfenapyr, and fipronil. Mortality due to horizontal exposure was evaluated at 10, 20, or 30 degrees C, with three ratios of topically treated donor ant corpses to live recipients (5, 10, or 20% donors). Bifenthrin had the greatest horizontal activity of the chemicals tested. For chlorfenapyr, the only treatments having higher mortality than controls were the highest percentage donors at either 10 or 30 degrees C. Horizontal activity of fipronil was temperature dependent only with the highest proportion of donors and was lower than that ofbifenthrin but higher than that of chlorfenapyr or thiamethoxam. Mean mortality due to thiamethoxam was similar to that with chlorfenapyr. Significant mortality occurred in all of the 20 and 30 degrees C thiamethoxam treatments, but none of the 10 degrees C treatments. Effectiveness as a barrier was evaluated by providing a choice between bridges treated with insecticide or water. Although bifenthrin did not provide an impenetrable barrier, it was the only treatment having fewer ants than its paired control bridge. Mortality data suggest that a reduction in recruitment rather than repellency account for this result.

  5. Modeling fire occurrence as a function of landscape

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

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

  6. Role of melatonin, serotonin 2B, and serotonin 2C receptors in modulating the firing activity of rat dopamine neurons.

    PubMed

    Chenu, Franck; Shim, Stacey; El Mansari, Mostafa; Blier, Pierre

    2014-02-01

    Melatonin has been widely used for the management of insomnia, but is devoid of antidepressant effect in the clinic. In contrast, agomelatine which is a potent melatonin receptor agonist is an effective antidepressant. It is, however, a potent serotonin 2B (5-HT(2B)) and serotonin 2C (5-HT(2C)) receptor antagonist as well. The present study was aimed at investigating the in vivo effects of repeated administration of melatonin (40 mg/kg/day), the 5-HT(2C) receptor antagonist SB 242084 (0.5 mg/kg/day), the selective 5-HT(2B) receptor antagonist LY 266097 (0.6 mg/kg/day) and their combination on ventral tegmental area (VTA) dopamine (DA), locus coeruleus (LC) norepinephrine (NE), and dorsal raphe nucleus (DRN) serotonin (5-HT) firing activity. Administration of melatonin twice daily increased the number of spontaneously active DA neurons but left the firing of NE neurons unaltered. Long-term administration of melatonin and SB 242084, by themselves, had no effect on the firing rate and burst parameters of 5-HT and DA neurons. Their combination, however, enhanced only the number of spontaneously active DA neurons, while leaving the firing of 5-HT neurons unchanged. The addition of LY 266097, which by itself is devoid of effect, to the previous regimen increased for DA neurons the number of bursts per minute and the percentage of spikes occurring in bursts. In conclusion, the combination of melatonin receptor activation as well as 5-HT(2C) receptor blockade resulted in a disinhibition of DA neurons. When 5-HT(2B) receptors were also blocked, the firing and the bursting activity of DA neurons were both enhanced, thus reproducing the effect of agomelatine.

  7. Ozone monitoring instrument observations of interannual increases in SO2 emissions from Indian coal-fired power plants during 2005-2012.

    PubMed

    Lu, Zifeng; Streets, David G; de Foy, Benjamin; Krotkov, Nickolay A

    2013-12-17

    Due to the rapid growth of electricity demand and the absence of regulations, sulfur dioxide (SO2) emissions from coal-fired power plants in India have increased notably in the past decade. In this study, we present the first interannual comparison of SO2 emissions and the satellite SO2 observations from the Ozone Monitoring Instrument (OMI) for Indian coal-fired power plants during the OMI era of 2005-2012. A detailed unit-based inventory is developed for the Indian coal-fired power sector, and results show that its SO2 emissions increased dramatically by 71% during 2005-2012. Using the oversampling technique, yearly high-resolution OMI maps for the whole domain of India are created, and they reveal a continuous increase in SO2 columns over India. Power plant regions with annual SO2 emissions greater than 50 Gg year(-1) produce statistically significant OMI signals, and a high correlation (R = 0.93) is found between SO2 emissions and OMI-observed SO2 burdens. Contrary to the decreasing trend of national mean SO2 concentrations reported by the Indian Government, both the total OMI-observed SO2 and annual average SO2 concentrations in coal-fired power plant regions increased by >60% during 2005-2012, implying the air quality monitoring network needs to be optimized to reflect the true SO2 situation in India.

  8. Ozone Monitoring Instrument Observations of Interannual Increases in SO2 Emissions from Indian Coal-fired Power Plants During 2005-2012

    NASA Technical Reports Server (NTRS)

    Lu, Zifeng; Streets, David D.; de Foy, Benjamin; Krotkov, Nickolay A.

    2014-01-01

    Due to the rapid growth of electricity demand and the absence of regulations, sulfur dioxide (SO2) emissions from coal-fired power plants in India have increased notably in the past decade. In this study, we present the first interannual comparison of SO2 emissions and the satellite SO2 observations from the Ozone Monitoring Instrument (OMI) for Indian coal-fired power plants during the OMI era of 2005-2012. A detailed unit-based inventory is developed for the Indian coal-fired power sector, and results show that its SO2 emissions increased dramatically by 71 percent during 2005-2012. Using the oversampling technique, yearly high-resolution OMI maps for the whole domain of India are created, and they reveal a continuous increase in SO2 columns over India. Power plant regions with annual SO2 emissions greater than 50 Gg year-1 produce statistically significant OMI signals, and a high correlation (R equals 0.93) is found between SO2 emissions and OMI-observed SO2 burdens. Contrary to the decreasing trend of national mean SO2 concentrations reported by the Indian Government, both the total OMI-observed SO2 and average SO2 concentrations in coal-fired power plant regions increased by greater than 60 percent during 2005-2012, implying the air quality monitoring network needs to be optimized to reflect the true SO2 situation in India.

  9. Holocene fire dynamics in Fennoscandia

    NASA Astrophysics Data System (ADS)

    Clear, Jennifer; Seppa, Heikki; Kuosmanen, Niina; Molinari, Chiara; Lehsten, Veiko; Allen, Katherine; Bradshaw, Richard

    2015-04-01

    Prescribed burning is advocated in Fennoscandia to promote regeneration and to encourage biodiversity. This method of forest management is based on the perception that fire was much more frequent in the recent past and over a century of active fire suppression has created a boreal forest ecosystem almost free of natural fire. The absence of fire is thought to have contributed to the widespread dominance of Picea abies (Norway spruce) with the successive spruce dominated forest further reducing fire ignition potential. However, humans have altered the natural fire dynamics of Fennoscandia since the early- to mid-Holocene and disentangling the anthropogenic driven fire dynamics from the natural fire dynamics is challenging. Through palaeoecology and sedimentary charcoal deposits we are able to explore the Holocene spatial and temporal variability and changing drivers of fire and vegetation dynamics in Fennoscandia. At the local-scale, two forest hollow environments (<20km apart) were analysed for high resolution macroscopic charcoal and pollen analysis and their fire and vegetation history are compared to identify unique and mutual changes in disturbance history. Pollen derived quantitative reconstruction of vegetation at both the local- and regional-scale identifies local-scale disturbance dynamics and large-scale ecosystem response. Spatio-temporal heterogeneity and variability in biomass burning is explored throughout Fennoscandia and Denmark to identify the changing drives of fire dynamics throughout the Holocene. Palaeo-vegetation reconstructions are compared to process-based, climate driven dynamic vegetation model output to test the significance of fire frequency as a driver of vegetation composition and dynamics. Early-Holocene fire regimes in Fennoscandia are driven by natural climate variations and fuel availability. The establishment and spread of Norway spruce is driven by an increase in continentality of climate, but local natural and anthropogenic

  10. Excellent c-Si surface passivation by thermal atomic layer deposited aluminum oxide after industrial firing activation

    NASA Astrophysics Data System (ADS)

    Liao, B.; Stangl, R.; Ma, F.; Mueller, T.; Lin, F.; Aberle, A. G.; Bhatia, C. S.; Hoex, B.

    2013-09-01

    We demonstrate that by using a water (H2O)-based thermal atomic layer deposited (ALD) aluminum oxide (Al2O3) film, excellent surface passivation can be attained on planar low-resistivity silicon wafers. Effective carrier lifetime values of up to 12 ms and surface recombination velocities as low as 0.33 cm s-1 are achieved on float-zone wafers after a post-deposition thermal activation of the Al2O3 passivation layer. This post-deposition activation is achieved using an industrial high-temperature firing process which is commonly used for contact formation of standard screen-printed silicon solar cells. Neither a low-temperature post-deposition anneal nor a silicon nitride capping layer is required in this case. Deposition temperatures in the 100-400 °C range and peak firing temperatures of about 800 °C (set temperature) are investigated. Photoluminescence imaging shows that the surface passivation is laterally uniform. Corona charging and capacitance-voltage measurements reveal that the negative fixed charge density near the AlOx/c-Si interface increases from 1.4 × 1012 to 3.3 × 1012 cm-2 due to firing, while the midgap interface defect density reduces from 3.3 × 1011 to 0.8 × 1011 cm-2 eV-1. This work demonstrates that direct firing activation of thermal ALD Al2O3 is feasible, which could be beneficial for solar cell manufacturing.

  11. Observational Activities at Manipur University, India (Abstract)

    NASA Astrophysics Data System (ADS)

    Singh, K. Y.; Meitei, I. A.; Singh, S. A.; Singh, R. B.

    2015-06-01

    (Abstract only) We have innovatively designed and constructed three observatories each costing a few hundred USD for housing three small Schmidt-Cassegrain type telescopes namely, Celestron CGE925, Celestron CGE1400, Meade 12-inch LX200GPS. These observatories are completely different in design and are found to be perfectly usable for doing serious work on astronomical observation and measurements. The observatory with the Celestron CGE1400 telescope has been inducted, since January 2012, as one of the observatories of the international “Orion Project” headquartered at Phoenix, Arizona, which is dedicated for photometric and spectroscopic observations of five bright variable stars of the Orion constellation namely, Betelgeuse (alpha Ori), Rigel (beta Ori), Mintaka (delta Ori), Alnilam (epsilon Ori) and Alnitak (zeta Ori). Using this observatory, we have been producing BVRI photometric data for the five stars of the Orion project. The other observatory with the Meade 12-inch LX200GPS telescope is being inducted into service for CCD photometric study of SU UMa stars in connection with implementation of a project funded by Indian Space Research Organization (ISRO). In the present paper, we would like to describe our self-built observatories, our observational facilities, the BVRI photometric data that we acquired for the Orion project, and our future plan for observation of variable stars of interest.

  12. DETERMINATION OF PERFLUOROCARBOXYLATES IN GROUNDWATER IMPACTED BY FIRE-FIGHTING ACTIVITY. (R821195)

    EPA Science Inventory

    Perfluorinated surfactants are used in aqueous film forming foam (AFFF)
    formulations, which are used to extinguish hydrocarbon-fuel fires. Virtually
    nothing is known about the occurrence of perfluorinated surfactants in the
    environment, in particular, at fire-train...

  13. Fire and nitrogen alter axillary bud number and activity in purple threeawn

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Belowground accumulation of vegetative buds provides a reservoir of meristems that can be utilized following disturbance. Perennial grass bud banks are the primary source of nearly all tiller growth, yet understanding of fire and nitrogen effects on bud banks is limited. We tested effects of fire ...

  14. Esterase in imported fire ants, Solenopsis invicata and S. richteri (Hymenoptera: Formicidae): activity, kinetics and variation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Black imported fire ant, Solenopsis richteri, is closely related to the notorious red imported fire ant, Solenopsis invicta. Despite being very similar in biology and behavior, S. invicta is a much more successful invader. In contrast to S. invicta that has invaded numberous countries and regions,...

  15. 76 FR 29011 - Agency Information Collection Activities; Submission for OMB Review; Comment Request; Fire...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-19

    ...; Fire Protection in Shipyard Employment ACTION: Notice. SUMMARY: The Department of Labor (DOL) is... (ICR) titled, ``Fire Protection in Shipyard Employment,'' to the Office of Management and Budget (OMB... not a toll-free number) or by e-mail at DOL_PRA_PUBLIC@dol.gov . SUPPLEMENTARY INFORMATION: The...

  16. Unaltered Network Activity and Interneuronal Firing During Spontaneous Cortical Dynamics In Vivo in a Mouse Model of Severe Myoclonic Epilepsy of Infancy

    PubMed Central

    De Stasi, Angela Michela; Farisello, Pasqualina; Marcon, Iacopo; Cavallari, Stefano; Forli, Angelo; Vecchia, Dania; Losi, Gabriele; Mantegazza, Massimo; Panzeri, Stefano; Carmignoto, Giorgio; Bacci, Alberto; Fellin, Tommaso

    2016-01-01

    Severe myoclonic epilepsy of infancy (SMEI) is associated with loss of function of the SCN1A gene encoding the NaV1.1 sodium channel isoform. Previous studies in Scn1a−/+ mice during the pre-epileptic period reported selective reduction in interneuron excitability and proposed this as the main pathological mechanism underlying SMEI. Yet, the functional consequences of this interneuronal dysfunction at the circuit level in vivo are unknown. Here, we investigated whether Scn1a−/+ mice showed alterations in cortical network function. We found that various forms of spontaneous network activity were similar in Scn1a−/+ during the pre-epileptic period compared with wild-type (WT) in vivo. Importantly, in brain slices from Scn1a−/+ mice, the excitability of parvalbumin (PV) and somatostatin (SST) interneurons was reduced, epileptiform activity propagated more rapidly, and complex synaptic changes were observed. However, in vivo, optogenetic reduction of firing in PV or SST cells in WT mice modified ongoing network activities, and juxtasomal recordings from identified PV and SST interneurons showed unaffected interneuronal firing during spontaneous cortical dynamics in Scn1a−/+ compared with WT. These results demonstrate that interneuronal hypoexcitability is not observed in Scn1a−/+ mice during spontaneous activities in vivo and suggest that additional mechanisms may contribute to homeostatic rearrangements and the pathogenesis of SMEI. PMID:26819275

  17. Role of the Duff Layer in Post-fire Soil Hydrology and Erosion: Field and Modelling Observations

    NASA Astrophysics Data System (ADS)

    Martin, Y. E.; Johnson, E. A.; Gallaway, J.

    2010-12-01

    Wildfires are generally thought to result in increased propensity for overland flow and soil erosion in the immediate years following the disturbance. Despite documentation of significant post-fire soil erosion in certain well-studied regional settings, the relevance of such findings to other regions remains questionable. In studies with notable post-fire soil erosion, the duff layer may be removed and hydrophobicity may develop, thus increasing the likelihood of soil erosion. Unfortunately, scenarios of negligible post-fire erosion most often go unreported by land managers and researchers, making it difficult to evaluate the pervasiveness of post-fire soil erosion and the environmental conditions under which notable post-fire soil erosion does and does not occur. A field study was designed to measure post-fire soil erosion in response to a high-intensity crown fire that occurred in the summer of 2003 within a closed canopy, boreal forest in Kootenay National Park, British Columbia, Canada. Measured soil erosion was very low in 2004 and 2005, although significant rainfall events did occur. We put forth the suggestion that a likely cause of our low erosion rates is the existence of notable post-fire duff coverage (duff includes both fermentation and humus soil organic layers) at our field site. The role of duff in soil hydrology is often ignored, perhaps because it is most often not seen as a limiting factor in soil infiltration. However, the duff layer provides a zone of detention storage for precipitation, thus enhancing infiltration into the underlying mineral soil. Furthermore, the duff layer presents a physical barrier to soil entrainment. Duff may thus help to effectively buffer the soil against the effects of high rainfall intensities. Few studies have explicitly highlighted the role of post-fire duff coverage in influencing soil erosional response. A widely held perception is that high-intensity crown fires remove most or all of the duff layer. In fact, this

  18. Fire ants actively control spacing and orientation within self-assemblages.

    PubMed

    Foster, Paul C; Mlot, Nathan J; Lin, Angela; Hu, David L

    2014-06-15

    To overcome obstacles and survive harsh environments, fire ants link their bodies together to form self-assemblages such as rafts, bridges and bivouacs. Such structures are examples of self-assembling and self-healing materials, as ants can quickly create and break links with one another in response to changes in their environment. Because ants are opaque, the arrangement of the ants within these three-dimensional networks was previously unknown. In this experimental study, we applied micro-scale computed tomography, or micro-CT, to visualize the connectivity, arrangement and orientation of ants within an assemblage. We identified active and geometric mechanisms that ants use to obtain favorable packing properties with respect to well-studied packing of inert objects such as cylinders. Ants use their legs to push against their neighbors, doubling their spacing relative to random packing of cylinders. These legs also permit active control of their orientation, an ability ants use to arrange themselves perpendicularly rather than in parallel. Lastly, we found an important role of ant polymorphism in promoting self-aggregation: a large distribution of ant sizes permits small ants to fit between the legs of larger ants, a phenomenon that increases the number of average connections per ant. These combined mechanisms lead to low packing fraction and high connectivity, which increase raft buoyancy and strength during flash floods.

  19. Comparison of the Hazard Mapping System (HMS) fire product to ground-based fire records in Georgia, USA

    NASA Astrophysics Data System (ADS)

    Hu, Xuefei; Yu, Chao; Tian, Di; Ruminski, Mark; Robertson, Kevin; Waller, Lance A.; Liu, Yang

    2016-03-01

    Biomass burning has a significant and adverse impact on air quality, climate change, and various ecosystems. The Hazard Mapping System (HMS) detects fires using data from multiple satellite sensors in order to maximize its fire detection rate. However, to date, the detection rate of the HMS fire product for small fires has not been well studied, especially using ground-based fire records. This paper utilizes the 2011 fire information compiled from ground observations and burn authorizations in Georgia to assess the comprehensiveness of the HMS active fire product. The results show that detection rates of the hybrid HMS increase substantially by integrating multiple satellite instruments. The detection rate increases dramatically from 3% to 80% with an increase in fire size from less than 0.02 km2 to larger than 2 km2, resulting in detection of approximately 12% of all recorded fires which represent approximately 57% of the total area burned. The spatial pattern of detection rates reveals that grid cells with high detection rates are generally located in areas where large fires occur frequently. The seasonal analysis shows that overall detection rates in winter and spring (12% and 13%, respectively) are higher than those in summer and fall (3% and 6%, respectively), mainly because of higher percentages of large fires (>0.19 km2) that occurred in winter and spring. The land cover analysis shows that detection rates are 2-7 percentage points higher in land cover types that are prone to large fires such as forestland and shrub land.

  20. Impact of fire on active layer and permafrost microbial communities and metagenomes in an upland Alaskan boreal forest

    PubMed Central

    Taş, Neslihan; Prestat, Emmanuel; McFarland, Jack W; Wickland, Kimberley P; Knight, Rob; Berhe, Asmeret Asefaw; Jorgenson, Torre; Waldrop, Mark P; Jansson, Janet K

    2014-01-01

    Permafrost soils are large reservoirs of potentially labile carbon (C). Understanding the dynamics of C release from these soils requires us to account for the impact of wildfires, which are increasing in frequency as the climate changes. Boreal wildfires contribute to global emission of greenhouse gases (GHG—CO2, CH4 and N2O) and indirectly result in the thawing of near-surface permafrost. In this study, we aimed to define the impact of fire on soil microbial communities and metabolic potential for GHG fluxes in samples collected up to 1 m depth from an upland black spruce forest near Nome Creek, Alaska. We measured geochemistry, GHG fluxes, potential soil enzyme activities and microbial community structure via 16SrRNA gene and metagenome sequencing. We found that soil moisture, C content and the potential for respiration were reduced by fire, as were microbial community diversity and metabolic potential. There were shifts in dominance of several microbial community members, including a higher abundance of candidate phylum AD3 after fire. The metagenome data showed that fire had a pervasive impact on genes involved in carbohydrate metabolism, methanogenesis and the nitrogen cycle. Although fire resulted in an immediate release of CO2 from surface soils, our results suggest that the potential for emission of GHG was ultimately reduced at all soil depths over the longer term. Because of the size of the permafrost C reservoir, these results are crucial for understanding whether fire produces a positive or negative feedback loop contributing to the global C cycle. PMID:24722629

  1. Impact of fire on active layer and permafrost microbial communities and metagenomes in an upland Alaskan boreal forest.

    PubMed

    Taş, Neslihan; Prestat, Emmanuel; McFarland, Jack W; Wickland, Kimberley P; Knight, Rob; Berhe, Asmeret Asefaw; Jorgenson, Torre; Waldrop, Mark P; Jansson, Janet K

    2014-09-01

    Permafrost soils are large reservoirs of potentially labile carbon (C). Understanding the dynamics of C release from these soils requires us to account for the impact of wildfires, which are increasing in frequency as the climate changes. Boreal wildfires contribute to global emission of greenhouse gases (GHG-CO2, CH4 and N2O) and indirectly result in the thawing of near-surface permafrost. In this study, we aimed to define the impact of fire on soil microbial communities and metabolic potential for GHG fluxes in samples collected up to 1 m depth from an upland black spruce forest near Nome Creek, Alaska. We measured geochemistry, GHG fluxes, potential soil enzyme activities and microbial community structure via 16SrRNA gene and metagenome sequencing. We found that soil moisture, C content and the potential for respiration were reduced by fire, as were microbial community diversity and metabolic potential. There were shifts in dominance of several microbial community members, including a higher abundance of candidate phylum AD3 after fire. The metagenome data showed that fire had a pervasive impact on genes involved in carbohydrate metabolism, methanogenesis and the nitrogen cycle. Although fire resulted in an immediate release of CO2 from surface soils, our results suggest that the potential for emission of GHG was ultimately reduced at all soil depths over the longer term. Because of the size of the permafrost C reservoir, these results are crucial for understanding whether fire produces a positive or negative feedback loop contributing to the global C cycle.

  2. Depopulation of rural landscapes exacerbates fire activity in the western Amazon.

    PubMed

    Uriarte, María; Pinedo-Vasquez, Miquel; DeFries, Ruth S; Fernandes, Katia; Gutierrez-Velez, Victor; Baethgen, Walter E; Padoch, Christine

    2012-12-26

    Destructive fires in Amazonia have occurred in the past decade, leading to forest degradation, carbon emissions, impaired air quality, and property damage. Here, we couple climate, geospatial, and province-level census data, with farmer surveys to examine the climatic, demographic, and land use factors associated with fire frequency in the Peruvian Amazon from 2000 to 2010. Although our results corroborate previous findings elsewhere that drought and proximity to roads increase fire frequency, the province-scale analysis further identifies decreases in rural populations as an additional factor. Farmer survey data suggest that increased burn scar frequency and size reflect increased flammability of emptying rural landscapes and reduced capacity to control fire. With rural populations projected to decline, more frequent drought, and expansion of road infrastructure, fire risk is likely to increase in western Amazonia. Damage from fire can be reduced through warning systems that target high-risk locations, coordinated fire fighting efforts, and initiatives that provide options for people to remain in rural landscapes.

  3. Depopulation of rural landscapes exacerbates fire activity in the western Amazon

    PubMed Central

    Uriarte, María; Pinedo-Vasquez, Miquel; DeFries, Ruth S.; Fernandes, Katia; Gutierrez-Velez, Victor; Baethgen, Walter E.; Padoch, Christine

    2012-01-01

    Destructive fires in Amazonia have occurred in the past decade, leading to forest degradation, carbon emissions, impaired air quality, and property damage. Here, we couple climate, geospatial, and province-level census data, with farmer surveys to examine the climatic, demographic, and land use factors associated with fire frequency in the Peruvian Amazon from 2000 to 2010. Although our results corroborate previous findings elsewhere that drought and proximity to roads increase fire frequency, the province-scale analysis further identifies decreases in rural populations as an additional factor. Farmer survey data suggest that increased burn scar frequency and size reflect increased flammability of emptying rural landscapes and reduced capacity to control fire. With rural populations projected to decline, more frequent drought, and expansion of road infrastructure, fire risk is likely to increase in western Amazonia. Damage from fire can be reduced through warning systems that target high-risk locations, coordinated fire fighting efforts, and initiatives that provide options for people to remain in rural landscapes. PMID:23236144

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

    PubMed

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

    2015-01-01

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

  5. Solar Activity Studies using Microwave Imaging Observations

    NASA Technical Reports Server (NTRS)

    Gopalswamy, N.

    2016-01-01

    We report on the status of solar cycle 24 based on polar prominence eruptions (PEs) and microwave brightness enhancement (MBE) information obtained by the Nobeyama radioheliograph. The north polar region of the Sun had near-zero field strength for more than three years (2012-2015) and ended only in September 2015 as indicated by the presence of polar PEs and the lack of MBE. The zero-polar-field condition in the south started only around 2013, but it ended by June 2014. Thus the asymmetry in the times of polarity reversal switched between cycle 23 and 24. The polar MBE is a good proxy for the polar magnetic field strength as indicated by the high degree of correlation between the two. The cross-correlation between the high- and low-latitude MBEs is significant for a lag of approximately 5.5 to 7.3 years, suggesting that the polar field of one cycle indicates the sunspot number of the next cycle in agreement with the Babcock-Leighton mechanism of solar cycles. The extended period of near-zero field in the north-polar region should result in a weak and delayed sunspot activity in the northern hemisphere in cycle 25.

  6. Fatigue-related firing of distal muscle nociceptors reduces voluntary activation of proximal muscles of the same limb.

    PubMed

    Kennedy, David S; McNeil, Chris J; Gandevia, Simon C; Taylor, Janet L

    2014-02-15

    With fatiguing exercise, firing of group III/IV muscle afferents reduces voluntary activation and force of the exercised muscles. These afferents can also act across agonist/antagonist pairs, reducing voluntary activation and force in nonfatigued muscles. We hypothesized that maintained firing of group III/IV muscle afferents after a fatiguing adductor pollicis (AP) contraction would decrease voluntary activation and force of AP and ipsilateral elbow flexors. In two experiments (n = 10) we examined voluntary activation of AP and elbow flexors by measuring changes in superimposed twitches evoked by ulnar nerve stimulation and transcranial magnetic stimulation of the motor cortex, respectively. Inflation of a sphygmomanometer cuff after a 2-min AP maximal voluntary contraction (MVC) blocked circulation of the hand for 2 min and maintained firing of group III/IV muscle afferents. After a 2-min AP MVC, maximal AP voluntary activation was lower with than without ischemia (56.2 ± 17.7% vs. 76.3 ± 14.6%; mean ± SD; P < 0.05) as was force (40.3 ± 12.8% vs. 57.1 ± 13.8% peak MVC; P < 0.05). Likewise, after a 2-min AP MVC, elbow flexion voluntary activation was lower with than without ischemia (88.3 ± 7.5% vs. 93.6 ± 3.9%; P < 0.05) as was torque (80.2 ± 4.6% vs. 86.6 ± 1.0% peak MVC; P < 0.05). Pain during ischemia was reported as Moderate to Very Strong. Postfatigue firing of group III/IV muscle afferents from the hand decreased voluntary drive and force of AP. Moreover, this effect decreased voluntary drive and torque of proximal unfatigued muscles, the elbow flexors. Fatigue-sensitive group III/IV muscle nociceptors act to limit voluntary drive not only to fatigued muscles but also to unfatigued muscles within the same limb.

  7. Cassini UVIS Observations Show Active Saturn's Rings

    NASA Astrophysics Data System (ADS)

    Esposito, L.; Colwell, J. E.; UVIS Team

    2004-12-01

    The Cassini Ultraviolet Imaging Spectrograph (UVIS) is part of the remote sensing payload of the NASA/ESA Cassini spacecraft. This spectrograph includes channels for extreme UV and far UV spectroscopic imaging, high speed photometry of stellar occultations, solar EUV occultation, and a hydrogen/deuterium absorption cell. We report our initial results from UVIS observations of Saturn's rings. Dynamic interactions between neutrals, ions, rings, moons and meteoroids produce a highly structured and time variable Saturn system Oxygen in the Saturn system dominates the magnetosphere. Observed fluctuations indicate close interactions with plasma sources. Stochastic events in the E ring may be the ultimate source. The spectral signature of water ice is seen on Phoebe and in Saturn's rings. Water ice is mixed non-uniformly with darker constituents. The high structure of the UV ring reflectance argues that collisional transport dominates ballistic transport in darkening the rings. Our preliminary results support the idea that rings are recycled fragments of moons: the current processes are more important than history and initial conditions. The spectra along the UVIS SOI radial scan indicate varying amounts of water ice. In the A ring, the ice fraction increases outward to a maximum at the outer edge. This large-scale variation is consistent with initially pure ice that has suffered meteoritic bombardment over the age of the Solar system (Cuzzi and Estrada 1998). We also see variations over scales of 1000 - 3000 km, which cannot be explained by this mechanism. Ballistic transport of spectrally neutral extrinsic pollutants from meteoroids striking the rings has a typical throw distance of 6000 km (Durisen et al 1989), too long to explain this finer structure. We propose a class of smaller renewal events, in which a small moon residing within the rings is shattered by an external impactor (Colwell and Esposito 1993, Barbara and Esposito 2002, Esposito and Colwell 2003). The

  8. Social observation enhances cross-environment activation of hippocampal place cell patterns.

    PubMed

    Mou, Xiang; Ji, Daoyun

    2016-10-03

    Humans and animals frequently learn through observing or interacting with others. The local enhancement theory proposes that presence of social subjects in an environment facilitates other subjects' understanding of the environment. To explore the neural basis of this theory, we examined hippocampal place cells, which represent spatial information, in rats as they stayed in a small box while a demonstrator rat running on a separate, nearby linear track, and as they ran on the same track themselves. We found that place cell firing sequences during self-running on the track also appeared in the box. This cross-environment activation occurred even prior to any self-running experience on the track and was absent without a demonstrator. Our data thus suggest that social observation can facilitate the observer's spatial representation of an environment without actual self-exploration. This finding may contribute to neural mechanisms of local enhancement.

  9. Idaho Fires

    NASA Technical Reports Server (NTRS)

    2001-01-01

    [figure removed for brevity, see original site] Figure 1 Click on image for larger version

    This full-frame ASTER image, acquired August 30, 2000, covers an area of 60 by 60 km in the Salmon River Mountains, Idaho. In this color infrared composite, vegetation is red, clouds are white, and smoke from forest fires is blue. An enlargement (Figure 1) covers an area of 12 x 15 km. A thermal infrared band is displayed in red, a short wave infrared band is displayed in green, and a visible band is displayed in blue. In this combination, fires larger than about 50 m appear yellow because they are bright in both infrared bands. Smaller fires appear green because they are too small to be seen by the 90 m thermal pixels, but large enough to be detected in the 30 m short wave infrared pixels. We are able to see through the smoke in the infrared bands, whereas in the visible bands, the smoke obscures detection of the active fires. This image is located at 44.8 degrees north latitude and 114.8 degrees west longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  10. Assessing fire risk in Portugal during the summer fire season

    NASA Astrophysics Data System (ADS)

    Dacamara, C. C.; Pereira, M. G.; Trigo, R. M.

    2009-04-01

    Since 1998, Instituto de Meteorologia, the Portuguese Weather Service has relied on the Canadian Fire Weather Index (FWI) System (van Wagner, 1987) to produce daily forecasts of fire risk. The FWI System consists of six components that account for the effects of fuel moisture and wind on fire behavior. The first three components, i.e. the Fine Fuel Moisture Code (FFMC), the Duff Moisture Code (DMC) and the Drought Code (DC) respectively rate the average moisture content of surface litter, decomposing litter, and organic (humus) layers of the soil. Wind effects are then added to FFMC leading to the Initial Spread Index (ISI) that rates fire spread. The remaining two fuel moisture codes (DMC and DC) are in turn combined to produce the Buildup Index (BUI) that is a rating of the total amount of fuel available for combustion. BUI is finally combined with ISI to produce the Fire Weather Index (FWI) that represents the rate of fire intensity. Classes of fire danger and levels of preparedness are commonly defined on an empirical way for a given region by calibrating the FWI System against wildfire activity as defined by the recorded number of events and by the observed burned area over a given period of time (Bovio and Camia, 1998). It is also a well established fact that distributions of burned areas are heavily skewed to the right and tend to follow distributions of the exponential-type (Cumming, 2001). Based on the described context, a new procedure is presented for calibrating the FWI System during the summer fire season in Portugal. Two datasets were used covering a 28-year period (1980-2007); i) the official Portuguese wildfire database which contains detailed information on fire events occurred in the 18 districts of Continental Portugal and ii) daily values of the six components of the FWI System as derived from reanalyses (Uppala et al., 2005) of the European Centre for Medium-Range Weather Forecasts (ECMWF). Calibration of the FWI System is then performed in two

  11. Modeling of the thermal influence of fires on the physicochemical properties and microbial activity of litter in cryogenic soils

    NASA Astrophysics Data System (ADS)

    Masyagina, O. V.; Tokareva, I. V.; Prokushkin, A. S.

    2014-08-01

    Periodic surface fires in the cryolithozone (the northern taiga subzone) are the main factor determining the qualitative and quantitative characteristics of the soil organic matter. The specific features of the changes in the physicochemical parameters and microbial activity of the organic horizons in the cryogenic soils under larch forests of the northern taiga after the impact of high temperatures were revealed. The temperatures of fires of different intensity were simulated in laboratory conditions. The thermal impact on the litter organic matter during the surface fires may increase the CO2 emission from the surface of the soil in the postfire communities due to the destruction of organic compounds only for a short time. After fires of high intensity with strong mineralization of the litters, during a period of more than 1 month, the pyrogenic effect on the organic horizons of the soils under the larch forests of the cryolithozone determined the reduction of the CO2 emissions in the freshly burned areas as compared to the intact stands.

  12. A NASA-NOAA Update on Global Fire Monitoring Capabilities for Studying Fire-Climate Interactions: Focus on Northern Eurasia

    NASA Astrophysics Data System (ADS)

    Gutman, G.; Csiszar, I.

    2012-04-01

    The global, long-term effects of fires are not well understood and we are learning more every year about its global impacts and potential feedbacks to climate change. The frequency, intensity, severity, and emissions of fires may be changing as a result of climate warming as has been manifested by the observations in northern Eurasia. The climate-fire interaction may produce important societal and environmental impacts in the long run. NASA and NOAA have been developing long-term fire datasets and improving systems to monitor active fires, study fire severity, fire growth, emissions into the atmosphere, and fire effects on carbon stocks. Almost every year there are regions in the world that experience particularly severe fires. For example, less than two years ago the European part of Russia was the focus of attention due to the anomalous heat and dry wave with record high temperatures that caused wildfires rage for weeks and that led to thousands of deaths. The fires also have spread to agricultural land and damaged crops, causing sharp increases of global wheat commodity prices. Remote sensing observations are widely used to monitor fire occurrence, fire spread; smoke dispersion, and atmospheric pollutant levels. In the context of climate warming and acute interest to large-scale emissions from various land-cover disturbances studying spatial-temporal dynamics of forest fire activity is critical. NASA supports several activities related to fires and the Earth system. These include GOFC-GOLD Fire Project Office at University of Maryland and the Rapid Response System for global fire monitoring. NASA has funded many research projects on biomass burning, which cover various geographic regions of the world and analyze impacts of fires on atmospheric carbon in support of REDD initiative, as well as on atmospheric pollution with smoke. Monitoring active fires, studying their severity and burned areas, and estimating fire-induced atmospheric emissions has been the

  13. Smoke Extracts and Nicotine, but not Tobacco Extracts, Potentiate Firing and Burst Activity of Ventral Tegmental Area Dopaminergic Neurons in Mice

    PubMed Central

    Marti, Fabio; Arib, Ouafa; Morel, Carole; Dufresne, Virginie; Maskos, Uwe; Corringer, Pierre-Jean; de Beaurepaire, Renaud; Faure, Philippe

    2011-01-01

    Nicotine prominently mediates the behavioral effects of tobacco consumption, either through smoking or when taking tobacco by snuff or chew. However, many studies question the exclusive role of nicotine in these effects. The use of preparations containing all the components of tobacco, such as tobacco and smoke extracts, may be more suitable than nicotine alone to investigate the behavioral effects of smoking and tobacco intake. In the present study, the electrophysiological effects of tobacco and smoke on ventral tegmental area dopaminergic (DA) neurons were examined in vivo in anesthetized wild-type (WT), β2-nicotinic acetylcholine receptor (nAChR) knockout (β2−/−), α4−/−, and α6−/− mice and compared with those of nicotine alone. In WT mice, smoke and nicotine had similar potentiating effects on DA cell activity, but the action of tobacco on neuronal firing was weak and often inhibitory. In particular, nicotine triggered strong bursting activity, whereas no bursting activity was observed after tobacco extract (ToE) administration. In β2−/− mice, nicotine or extract elicited no modification of the firing patterns of DA cells, indicating that extract acts predominantly through nAChRs. The differences between DA cell activation profiles induced by tobacco and nicotine alone observed in WT persisted in α6−/− mice but not in α4−/− mice. These results would suggest that tobacco has lower addiction-generating properties compared with either nicotine alone or smoke. The weak activation and prominent inhibition obtained with ToEs suggest that tobacco contains compounds that counteract some of the activating effects of nicotine and promote inhibition on DA cell acting through α4β2*-nAChRs. The nature of these compounds remains to be elucidated. It nevertheless confirms that nicotine is the main substance involved in the tobacco addiction-related activation of mesolimbic DA neurons. PMID:21716264

  14. Comparison of Interglacial fire dynamics in Southern Africa

    NASA Astrophysics Data System (ADS)

    Brücher, Tim; Daniau, Anne-Laure

    2016-04-01

    Responses of fire activity to a change in climate are still uncertain and biases exist by integrating this non-linear process into global modeling of the Earth system. Warming and regional drying can force fire activity in two opposite directions: an increase in fire in fuel supported ecosystems or a fire reduction in fuel-limited ecosystems. Therefore, climate variables alone can not be used to estimate the fire risk because vegetation variability is an important determinant of fire dynamics and responds itself to change in climate. Southern Africa (south of 20°S) paleofire history reconstruction obtained from the analysis of microcharcoal preserved in a deep-sea core located off Namibia reveals changes of fire activity on orbital timescales in the precession band. In particular, increase in fire is observed during glacial periods, and reduction of fire during interglacials such as the Eemian and the Holocene. The Holocene was characterized by even lower level of fire activity than Eemian. Those results suggest the alternance of grass-fueled fires during glacials driven by increase in moisture and the development of limited fueled ecosystems during interglacials characterized by dryness. Those results question the simulated increase in the fire risk probability projected for this region under a warming and drying climate obtained by Pechony and Schindell (2010). To explore the validity of the hypotheses we conducted a data-model comparison for both interglacials from 126.000 to 115.000 BP for the Eemian and from 8.000 to 2.000 BP for the Holocene. Data out of a transient, global modeling study with a Vegetation-Fire model of full complexity (JSBACH) is used, driven by a Climate model of intermediate complexity (CLIMBER). Climate data like precipitation and temperature as well as vegetation data like soil moisture, productivity (NPP) on plant functional type level are used to explain trends in fire activity. The comparison of trends in fire activity during the

  15. Developing a Global, Short-Term Fire Weather Forecasting Tool Using NWP Input Meteorology and Satellite Fire Data

    NASA Astrophysics Data System (ADS)

    Peterson, D. A.; Hyer, E. J.; Wang, J.

    2011-12-01

    In order to meet the emerging need for better estimates of biomass burning emissions in air quality and climate models, a statistical model is developed to characterize the effect of a given set of meteorological conditions on the following day's fire activity, including ignition and spread potential. Preliminary tests are conducted within several spatial domains of the North American boreal forest by investigating a wide range of meteorological information, including operational fire weather forecasting indices, such as the Canadian Forest Fire Danger Rating System (CFFDRS). However, rather than using local noon surface station data, the six components of the CFFDRS are modified to use inputs from the North America Regional Reanalysis (NARR) and the Navy's Operational Global Atmospheric Prediction System Model (NOGAPS). The Initial Spread Index (ISI) and the Fire Weather Index (FWI) are shown to be the most relevant components of the CFFDRS for short-term changes in fire activity. However, both components are found to be highly sensitive to variations in relative humidity and wind speed input data. Several variables related to fire ignition from dry lighting, such as instability and the synoptic pattern, are also incorporated. Cases of fire ignition, growth, decay, and extinction are stratified using satellite fire observations from the Geostationary Operational Environmental Satellites (GOES) and the MODerate Resolution Imaging Spectroradiometer (MODIS) and compared to the available suite of meteorological information. These comparisons reveal that combinations of meteorological variables, such as the FWI, ISI, and additional indices developed for this study, produce the greatest separability between major fire growth and decay cases, which are defined by the observed change in fire counts and fire radiative power. This information is used to derive statistical relationships affecting the short-term changes in fire activity and subsequently applied to other

  16. Determination of platinum and palladium in geological materials by neutron-activation analysis after fire-assay preconcentration

    USGS Publications Warehouse

    Rowe, J.J.; Simon, F.O.

    1971-01-01

    Fire-asay preconcentration followed by neutron-activation analysis permits the determination of as little as 0.5 ppM of platinum and 0.5 ppM of palladium on a 20-g sample. Platinum and palladium are separated with carriers and beta-counted. Results for the platinum and palladium content of seven U.S.G.S. standard rocks are presented. ?? 1971.

  17. Mexican forest fires and their decadal variations

    NASA Astrophysics Data System (ADS)

    Velasco Herrera, Graciela

    2016-11-01

    A high forest fire season of two to three years is regularly observed each decade in Mexican forests. This seems to be related to the presence of the El Niño phenomenon and to the amount of total solar irradiance. In this study, the results of a multi-cross wavelet analysis are reported based on the occurrence of Mexican forest fires, El Niño and the total solar irradiance for the period 1970-2014. The analysis shows that Mexican forest fires and the strongest El Niño phenomena occur mostly around the minima of the solar cycle. This suggests that the total solar irradiance minima provide the appropriate climatological conditions for the occurrence of these forest fires. The next high season for Mexican forest fires could start in the next solar minimum, which will take place between the years 2017 and 2019. A complementary space analysis based on MODIS active fire data for Mexican forest fires from 2005 to 2014 shows that most of these fires occur in cedar and pine forests, on savannas and pasturelands, and in the central jungles of the Atlantic and Pacific coasts.

  18. Estimating fire radiative power obscuration by tree canopies through laboratory experiments: Estimating fire radiative energy in a longleaf pine forest from airborne thermal imagery

    NASA Astrophysics Data System (ADS)

    Mathews, William

    Remote sensing has been proven as a useful tool in characterizing the effects of fire on a landscape scale. The radiant energy released during biomass burning can be measured remotely, and is directly related to the rate biomass consumed from the fire. This is an important measurement as it can characterize fire effects on the ground along with provide important information about the amount of gases produced by the fire. One source of error associated with estimating the fire radiative energy (FRE) remotely is the obscuration of the signal by the forest canopy. We quantify the relationship between canopy cover and the amount of energy observed by a sensor rom laboratory experiments. A prescribed fire was conducted in northwestern Florida and a suite of pre-, active, and post-fire measurements were taken by an interdisciplinary team. From those data we measured the amount of biomass consumed by the fire FRE estimates.

  19. Increased dopamine D2 receptor activity in the striatum alters the firing pattern of dopamine neurons in the ventral tegmental area

    PubMed Central

    Krabbe, Sabine; Duda, Johanna; Schiemann, Julia; Poetschke, Christina; Schneider, Gaby; Kandel, Eric R.; Liss, Birgit; Roeper, Jochen; Simpson, Eleanor H.

    2015-01-01

    There is strong evidence that the core deficits of schizophrenia result from dysfunction of the dopamine (DA) system, but details of this dysfunction remain unclear. We previously reported a model of transgenic mice that selectively and reversibly overexpress DA D2 receptors (D2Rs) in the striatum (D2R-OE mice). D2R-OE mice display deficits in cognition and motivation that are strikingly similar to the deficits in cognition and motivation observed in patients with schizophrenia. Here, we show that in vivo, both the firing rate (tonic activity) and burst firing (phasic activity) of identified midbrain DA neurons are impaired in the ventral tegmental area (VTA), but not in the substantia nigra (SN), of D2R-OE mice. Normalizing striatal D2R activity by switching off the transgene in adulthood recovered the reduction in tonic activity of VTA DA neurons, which is concordant with the rescue in motivation that we previously reported in our model. On the other hand, the reduction in burst activity was not rescued, which may be reflected in the observed persistence of cognitive deficits in D2R-OE mice. We have identified a potential molecular mechanism for the altered activity of DA VTA neurons in D2R-OE mice: a reduction in the expression of distinct NMDA receptor subunits selectively in identified mesolimbic DA VTA, but not nigrostriatal DA SN, neurons. These results suggest that functional deficits relevant for schizophrenia symptoms may involve differential regulation of selective DA pathways. PMID:25675529

  20. Soil microbiological properties and enzymatic activities of long-term post-fire recovery in dry and semiarid Aleppo pine (Pinus halepensis M.) forest stands

    NASA Astrophysics Data System (ADS)

    Hedo, J.; Lucas-Borja, M. E.; Wic, C.; Andrés Abellán, M.; de Las Heras, J.

    2014-10-01

    Wildfires affecting forest ecosystems and post-fire silvicultural treatments may cause considerable changes in soil properties. The capacity of different microbial groups to recolonize soil after disturbances is crucial for proper soil functioning. The aim of this work was to investigate some microbial soil properties and enzyme activities in semiarid and dry Aleppo pine (Pinus halepensis M.) forest stands. Different plots affected by a wildfire event 17 years ago without or with post-fire silvicultural treatments five years after the fire event were selected. A mature Aleppo pine stand unaffected by wildfire and not thinned was used as a control. Physicochemical soil properties (soil texture, pH, carbonates, organic matter, electrical conductivity, total N and P), soil enzymes (urease, phosphatase, β-glucosidase and dehydrogenase activities), soil respiration and soil microbial biomass carbon were analysed in the selected forests areas and plots. The main finding was that long time after this fire event produces no differences in the microbiological soil properties and enzyme activities of soil after comparing burned and thinned, burned and not thinned, and mature plots. Thus, the long-term consequences and post-fire silvicultural management in the form of thinning have a significant effect on the site recovery after fire. Moreover, significant site variation was generally seen in soil enzyme activities and microbiological parameters. We conclude that total vegetation restoration normalises microbial parameters, and that wildfire and post-fire silvicultural treatments are not significant factors of soil properties after 17 years.

  1. Fires in Southern Georgia

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Several large fires were burning in southern Georgia on April 29, 2007, when the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite passed overhead and captured this image. Places where MODIS detected actively burning fires are outlined in red. The Roundabout Fire sprang up on April 27, according to the U.S. Southern Area Coordination Center, and was about 3,500 acres as of April 30. That fire was threatening homes in the community of Kirkland. Meanwhile, south of Waycross, two large blazes were burning next to each other in the northern part of Okefenokee Swamp. The Sweat Farm Road Fire threatened the town of Waycross in previous weeks, but at the end of April, activity had moved to the southeastern perimeter. The fire had affected more than 50,000 acres of timber (including pine tree plantations) and swamps. Scores of residences scattered throughout the rural area are threatened. The Big Turnaround Complex is burning to the east. The 26,000-acre fire was extremely active over the weekend, with flame lengths more than 60 feet (just over 18 meters) in places. The two blazes appeared to overlap in fire perimeter maps available from the U.S. Geospatial Multi-Agency Coordination Team. According to the Southern Area Coordination Center morning report on April 30, the Sweat Farm Road Fire 'will be a long term fire. Containment and control will depend on significant rainfall, due to the inaccessible swamp terrain.' No expected containment date was available for the Big Turnaround Complex Fire, either. Describing that fire, the report stated, 'Heavy fuel loading, high fire danger, and difficulty of access continue to hamper suppression efforts.' The large image provided above has a spatial resolution (level of detail) of 250 meters per pixel. The MODIS Rapid Response Team provides twice-daily images of the region in additional resolutions. They also provide a version of the image that shows smoke plumes stretching out across the Atlantic Ocean.

  2. Nitrogen oxides and PAN in plumes from boreal fires during ARCTAS-B and their impact on ozone: an integrated analysis of aircraft and satellite observations

    NASA Astrophysics Data System (ADS)

    Alvarado, M. J.; Logan, J. A.; Mao, J.; Apel, E.; Riemer, D.; Blake, D.; Cohen, R. C.; Min, K.-E.; Perring, A. E.; Browne, E. C.; Wooldridge, P. J.; Diskin, G. S.; Sachse, G. W.; Fuelberg, H.; Sessions, W. R.; Harrigan, D. L.; Huey, G.; Liao, J.; Case-Hanks, A.; Jimenez, J. L.; Cubison, M. J.; Vay, S. A.; Weinheimer, A. J.; Knapp, D. J.; Montzka, D. D.; Flocke, F. M.; Pollack, I. B.; Wennberg, P. O.; Kurten, A.; Crounse, J.; St. Clair, J. M.; Wisthaler, A.; Mikoviny, T.; Yantosca, R. M.; Carouge, C. C.; Le Sager, P.

    2010-10-01

    We determine enhancement ratios for NOx, PAN, and other NOy species from boreal biomass burning using aircraft data obtained during the ARCTAS-B campaign and examine the impact of these emissions on tropospheric ozone in the Arctic. We find an initial emission factor for NOx of 1.06 g NO per kg dry matter (DM) burned, much lower than previous observations of boreal plumes, and also one third the value recommended for extratropical fires. Our analysis provides the first observational confirmation of rapid PAN formation in a boreal smoke plume, with 40% of the initial NOx emissions being converted to PAN in the first few hours after emission. We find little clear evidence for ozone formation in the boreal smoke plumes during ARCTAS-B in either aircraft or satellite observations, or in model simulations. Only a third of the smoke plumes observed by the NASA DC8 showed a correlation between ozone and CO, and ozone was depleted in the plumes as often as it was enhanced. Special observations from the Tropospheric Emission Spectrometer (TES) also show little evidence for enhanced ozone in boreal smoke plumes between 15 June and 15 July 2008. Of the 22 plumes observed by TES, only 4 showed ozone increasing within the smoke plumes, and even in those cases it was unclear that the increase was caused by fire emissions. Using the GEOS-Chem atmospheric chemistry model, we show that boreal fires during ARCTAS-B had little impact on the median ozone profile measured over Canada, and had little impact on ozone within the smoke plumes observed by TES.

  3. Nitrogen oxides and PAN in plumes from boreal fires during ARCTAS-B and their impact on ozone: an integrated analysis of aircraft and satellite observations

    NASA Astrophysics Data System (ADS)

    Alvarado, M. J.; Logan, J. A.; Mao, J.; Apel, E.; Riemer, D.; Blake, D.; Cohen, R. C.; Min, K.-E.; Perring, A. E.; Browne, E. C.; Wooldridge, P. J.; Diskin, G. S.; Sachse, G. W.; Fuelberg, H.; Sessions, W. R.; Harrigan, D. L.; Huey, G.; Liao, J.; Case-Hanks, A.; Jimenez, J. L.; Cubison, M. J.; Vay, S. A.; Weinheimer, A. J.; Knapp, D. J.; Montzka, D. D.; Flocke, F. M.; Pollack, I. B.; Wennberg, P. O.; Kurten, A.; Crounse, J.; St. Clair, J. M.; Wisthaler, A.; Mikoviny, T.; Yantosca, R. M.; Carouge, C. C.; Le Sager, P.

    2010-06-01

    We determine enhancement ratios for NOx, PAN, and other NOy species from boreal biomass burning using aircraft data obtained during the ARCTAS-B campaign and examine the impact of these emissions on tropospheric ozone in the Arctic. We find an initial emission factor for NOx of 1.06 g NO per kg dry matter (DM) burned, much lower than previous observations of boreal plumes, and also one third the value recommended for extratropical fires. Our analysis provides the first observational confirmation of rapid PAN formation in a boreal smoke plume, with 40% of the initial NOx emissions being converted to PAN in the first few hours after emission. We find little clear evidence for ozone formation in the boreal smoke plumes during ARCTAS-B in either aircraft or satellite observations, or in model simulations. Only a third of the smoke plumes observed by the NASA DC8 showed a correlation between ozone and CO, and ozone was depleted in the plumes as often as it was enhanced. Special observations from the Tropospheric Emission Spectrometer (TES) also show little evidence for enhanced ozone in boreal smoke plumes between 15 June and 15 July 2008. Of the 22 plumes observed by TES, only 4 showed ozone increasing within the smoke plumes, and even in those cases it was unclear that the increase was caused by fire emissions. Using the GEOS-Chem atmospheric chemistry model, we show that boreal fires during ARCTAS-B had little impact on the median ozone profile measured over Canada, and had little impact on ozone within the smoke plumes observed by TES.

  4. Using Global Geo-information for Disaster Risk Reduction Following the UN Sendai Framework: Climate Change and Disruptions to Global Fire Activity

    NASA Astrophysics Data System (ADS)

    Ganz, D.

    2015-12-01

    Despite the knowledge that climate induced fire activity will threaten ecosystems and human well-being throughout the world, there are few fire projections at global scales and almost none from a broad range of global climate models (GCMs). The following study presents global fire datasets and environmental variables used to build spatial statistical baseline models of fire probability and examine the environmental controls on fire activity. As the UN Sendai Framework requires an update of hazard databases and an integration additional manmade hazards in the calculation of risks, this global fire study examines the magnitude and direction of change over two projection periods, 2010-2039 and 2070-2099. From the GCM ensemble results, the study identified areas of consensus for increases or decreases in fires. This type of information may inform policies and strategies of fire-prone nations to better utilize baseline and projection geo-information for enhancing disaster preparedness for what the Sendai Framework is calling an effective response, and to "Build Back Better" in recovery, rehabilitation and reconstruction. Certain biomes are sensitive to constraints on biomass productivity while others to atmospheric conditions promoting combustion. Substantial and rapid shifts are projected for future fire activity across vast portions of the globe. In the near term, the most consistent increases in fire activity occur in biomes with already somewhat warm climates; decreases are less pronounced and concentrated primarily in a few tropical and subtropical biomes. However, models do not agree on the direction of near-term changes across more than 50% of terrestrial lands. Although these models demonstrated that long-term environmental norms captured chronic fire probability patterns, future work is needed to assess how annual variation in climate variables could add more explanatory power. This study provides an examination of global disruptions to fire activity using a

  5. Fatigue-related firing of muscle nociceptors reduces voluntary activation of ipsilateral but not contralateral lower limb muscles.

    PubMed

    Kennedy, David S; Fitzpatrick, Siobhan C; Gandevia, Simon C; Taylor, Janet L

    2015-02-15

    During fatiguing upper limb exercise, maintained firing of group III/IV muscle afferents can limit voluntary drive to muscles within the same limb. It is not known if this effect occurs in the lower limb. We investigated the effects of group III/IV muscle afferent firing from fatigued ipsilateral and contralateral extensor muscles and ipsilateral flexor muscles of the knee on voluntary activation of the knee extensors. In three experiments, we examined voluntary activation of the knee extensors by measuring changes in superimposed twitches evoked by femoral nerve stimulation. Subjects attended on 2 days for each experiment. On one day a sphygmomanometer cuff occluded blood flow of the fatigued muscles to maintain firing of group III/IV muscle afferents. After a 2-min extensor contraction (experiment 1; n = 9), mean voluntary activation was lower with than without maintained ischemia (47 ± 19% vs. 87 ± 8%, respectively; P < 0.001). After a 2-min knee flexor maximal voluntary contraction (MVC) (experiment 2; n = 8), mean voluntary activation was also lower with than without ischemia (59 ± 21% vs. 79 ± 9%; P < 0.01). After the contralateral (left) MVC (experiment 3; n = 8), mean voluntary activation of the right leg was similar with or without ischemia (92 ± 6% vs. 93 ± 4%; P = 0.65). After fatiguing exercise, activity in group III/IV muscle afferents reduces voluntary activation of the fatigued muscle and nonfatigued antagonist muscles in the same leg. However, group III/IV muscle afferents from the fatigued left leg had no effect on the unfatigued right leg. This suggests that any "crossover" of central fatigue in the lower limbs is not mediated by group III/IV muscle afferents.

  6. The Ofidia Project: a Retrospective Fire Danger Forecast Analysis in Mediterranean Environment

    NASA Astrophysics Data System (ADS)

    Sirca, C.; Bacciu, V. M.; Salis, M.; Mirto, L.; Fiore, S.; Aloisio, G.; Spano, D.

    2015-12-01

    OFIDIA (Operational FIre Danger preventIon plAtform) is a two-year project started in May 2013 funded by the European Territorial Cooperation Programme Greece Italy (2007 - 2013). The project aims to improve the operational capability of forecasting, preventing, and fighting forest wildfires, and enhance the cross-border cooperation for fire danger assessment. More specifically, OFIDIA aims at developing an operational fire danger prevention platform, with the ability for near real-time fire danger forecast and fire behaviour analysis in Apulia (Italy) and Epirus (Greece) regions to help forest fires services in the effective prevention and response to forecasted danger.One of the preliminary activities of the project was the evaluation of fire danger performances by analysing the relationship between the predicted daily fire danger and observed fire activity (number of fires and area burned). To achieve this task, fire activity and danger patterns were characterised and their relationships were investigated for the period 2000-2012. The Italian Forest Service (CFS, Corpo Forestale dello Stato) provided fire statistics at NUT03 level. The data were homogenized and uncertainties corrected, and then burned area and number of fires were analysed according to the main fire regime characteristics (seasonality, fire return interval, fire incidence, fire size distribution, etc). Then, three fire danger models (FFWI, FWI, and IFI) were selected and computed starting from the fifth-generation Pennsylvania State University-National Center for Atmospheric Research Mesoscale Model (MM5) forecast.Results showed a high inter- and intra-annual variability in fire activiy, also considering the different type of affected vegetation. As for other Mediterranean areas, a smaller number of large fires caused a high proportion of burned area. Furthermore, fire activity showed significant correlations with the outputs obtained by the applied models. High relationships were found between

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

    USGS Publications Warehouse

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

    2016-01-01

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

  8. Developing and evaluating a synoptic and diurnally varying time series of global fire emissions

    NASA Astrophysics Data System (ADS)

    Mu, M.; Randerson, J. T.; Giglio, L.; van der Werf, G. R.; Hyer, E.; Prins, E.

    2008-12-01

    To assess how recent changes in fire activity and burned area influence climate and human health, we need to improve our understanding of fire emissions. Information on synoptic and diurnal time scales may be particularly relevant for capturing interactions between climate drivers of fire activity and atmospheric transport of particulate and trace gas emissions. Developing emissions time series at this high temporal resolution requires combining active fire products with burned area information that is typically available only at monthly or annual intervals. Here we used several different active fire products from MODIS and GOES to distribute monthly fire emissions from Global Fire Emissions Database version 2 (GFEDv2) at a 3-hour time step. This process required several steps. First, we used the 8-day overpass corrected climate modeling grid active fires from MODIS AQUA and TERRA to distribute emissions during 8-day intervals within a year. In a second step we distributed emissions day by day within each 8-day interval using raw active fire detections from MODIS. In a final step we used GOES active fire observations to construct mean diurnal cycles for different vegetation types and latitude zones. These mean cycles were then applied to the daily emissions. The results show reasonable agreement of daily fire activity as compared with GOES, VIRS, and ATSR active fire products. We constructed mean diurnal cycles from GOES observations for three different land types: forest, shrublands and savannas, and grasses and crops in different latitude zones. We found that maximum fire activity occurred in the early afternoon 12:00-3:00 PM and minimum fire activity occurred at night from 00:00 to 6:00 AM. The diurnal cycles varied substantially in different land cover types and regions with boreal forest fires, for example, showing substantially more burning in late afternoon and night than fires in grassland or cropland areas. Fires in shrublands and savannas and grasslands

  9. A Global Tour of Fire

    NASA Video Gallery

    Fire observations from around the world taken over nearly 10 years are shown in this visualization of NASA satellite data. This visualization leads viewers on a narrated global tour of fire detecti...

  10. Context Matters: Systematic Observation of Place-Based Physical Activity.

    PubMed

    McKenzie, Thomas L

    2016-12-01

    Physical activity is place-based, and being able to assess the number of people and their characteristics in specific locations is important both for public health surveillance and for practitioners in their design of physical activity spaces and programs. Although physical activity measurement has improved recently, many investigators avoid or are at a loss regarding the assessment of physical activity in explicit locations, especially in open environments where many people come and go in a seemingly indiscriminate fashion. Direct, systematic observation exceeds other methods in simultaneously assessing physical activity and the contexts in which it occurs. This commentary summarizes the development and use of 2 validated observation tools: the System for Observing Play and Leisure in Youth (SOPLAY) and System for Observing Play and Active Recreation in Communities (SOPARC). Their use is well supported by both behavior-analytic principles and social-ecological theory, and their methods have utility for both researchers and practitioners.

  11. Calcium influx through N-type channels and activation of SK and TRP-like channels regulates tonic firing of neurons in rat paraventricular thalamus.

    PubMed

    Wong, Adrian Y C; Borduas, Jean-Francois; Clarke, Stephen; Lee, Kevin F H; Béïque, Jean-Claude; Bergeron, Richard

    2013-11-01

    The thalamus is a major relay and integration station in the central nervous system. While there is a large body of information on the firing and network properties of neurons contained within sensory thalamic nuclei, less is known about the neurons located in midline thalamic nuclei, which are thought to modulate arousal and homeostasis. One midline nucleus that has been implicated in mediating stress responses is the paraventricular nucleus of the thalamus (PVT). Like other thalamic neurons, these neurons display two distinct firing modes, burst and tonic. In contrast to burst firing, little is known about the ionic mechanisms modulating tonic firing in these cells. Here we performed a series of whole cell recordings to characterize tonic firing in PVT neurons in acute rat brain slices. We found that PVT neurons are able to fire sustained, low-frequency, weakly accommodating trains of action potentials in response to a depolarizing stimulus. Unexpectedly, PVT neurons displayed a very high propensity to enter depolarization block, occurring at stimulus intensities that would elicit tonic firing in other thalamic neurons. The tonic firing behavior of these cells is modulated by a functional interplay between N-type Ca(2+) channels and downstream activation of small-conductance Ca(2+)-dependent K(+) (SK) channels and a transient receptor potential (TRP)-like conductance. Thus these ionic conductances endow PVT neurons with a narrow dynamic range, which may have fundamental implications for the integrative properties of this nucleus.

  12. Standard-resolution TOVS observations for the FIRE/SRB Wisconsin experiment region from October 9 through November 2, 1986

    NASA Technical Reports Server (NTRS)

    Whitlock, Charles H.; Lecroy, Stuart R.; Darnell, Wayne L.

    1987-01-01

    Maps and concise tables are presented which show TIROS Operational Vertical Sounder (TOVS) box centroid locations, box size, and vertical sounding products from the NOAA-6 and -9 satellites for the FIRE/SRB (First ISCCP Regional Experiment/Surface Radiation Budget) Wisconsin experiment region during October 9 through November 2, 1986. In addition to the operational standard products, relative reflectance is calculated and presented based on values from HIRS/2 Band 20 measurements.

  13. Near and far field contamination modeling in a large scale enclosure: Fire Dynamics Simulator comparisons with measured observations.

    PubMed

    Ryder, Noah L; Schemel, Christopher F; Jankiewicz, Sean P

    2006-03-17

    The occurrence of a fire, no matter how small, often exposes objects to significant levels of contamination from the products of combustion. The production and dispersal of these contaminants has been an issue of relevance in the field of fire science for many years, though little work has been done to examine the contamination levels accumulated within an enclosure some time after an incident. This phenomenon is of great importance when considering the consequences associated with even low level contamination of sensitive materials, such as food, pharmaceuticals, clothing, electrical equipment, etc. Not only does such exposure present a localized hazard, but also the shipment of contaminated goods places distant recipients at risk. It is the intent of this paper to use a well-founded computational fluid dynamic (CFD) program, the Fire Dynamics Simulator (FDS), a large eddy simulation (LES) code developed by National Institute of Standards and Technology (NIST), to model smoke dispersion in order to assess the subject of air contamination and post fire surface contamination in a warehouse facility. Measured results are then compared with the results from the FDS model. Two components are examined: the production rate of contaminates and the trajectory of contaminates caused by the forced ventilation conditions. Each plays an important role in determining the extent to which the products of combustion are dispersed and the levels to which products are exposed to the contaminants throughout the enclosure. The model results indicate a good first-order approximation to the measured surface contamination levels. The proper application of the FDS model can provide a cost and time efficient means of evaluating contamination levels within a defined volume.

  14. Biscuit Fire, OR

    NASA Technical Reports Server (NTRS)

    2002-01-01

    In southwest Oregon, the Biscuit Fire continues to grow. This image, acquired from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite on August 14, 2002, shows the pillars of smoke arising from the fires. Active fire areas are in red. More than 6,000 fire personnel are assigned to the Biscuit Fire alone, which was 390,276 acres as of Thursday morning, August 15, and only 26 percent contained. Among the resources threatened are thousands of homes, three nationally designated wild and scenic rivers, and habitat for several categories of plants and animals at risk of extinction. Firefighters currently have no estimate as to when the fire might be contained.

    With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER will image Earth for the next six years to map and monitor the changing surface of our planet.

    ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products.

    The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping, and monitoring dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.

    Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, Calif., is the U.S. science team leader; Bjorn Eng of JPL is the project manager

  15. Intumescent Coatings as Fire Retardants

    NASA Technical Reports Server (NTRS)

    Fish, R. H.; Fohlen, G. M.; Parker, J. A.; Sawko, P. M.

    1970-01-01

    Fire-retardant paint, when activated by the heat of fire, reacts to form a thick, low-density, polymeric coating or char layer. Water vapor and sulphur dioxide are released during the intumescent reaction.

  16. An aerosol boomerang: Rapid around-the-world transport of smoke from the December 2006 Australian forest fires observed from space

    NASA Astrophysics Data System (ADS)

    Dirksen, Ruud J.; Folkert Boersma, K.; de Laat, Jos; Stammes, Piet; van der Werf, Guido R.; Val Martin, Maria; Kelder, Hennie M.

    2009-11-01

    We investigate rapid around-the-world transport of a smoke aerosol plume released by intense forest fires in southeastern Australia in December 2006. During the first half of December 2006, southeastern Australia suffered from severe drought and exceptionally high temperatures. On 14 December 2006, a passing cold front in combination with the intense heat from the fires causing pyro-convective lofting, injected a large mass of aerosol particles into the jet stream. We track the resulting aerosol plume using Aerosol Absorbing Index (AAI) observations from the Ozone Monitoring Instrument (OMI) and find that it circumnavigated the world in 12 days. Using observations from OMI and the CALIOP (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation) spaceborne lidar, we show that the plume resided in the high troposphere at different stages of its evolution. In absence of CALIOP data, we explored OMI O2-O2 pressures to obtain information on the aerosol plume height. Detailed radiative transfer calculations suggest that the current OMI O2-O2 retrievals contain useful information on the altitude of the aerosol plume under specific conditions (high AAI, no clouds below). The observed two-dimensional evolution of the smoke aerosol plume and the vertical distribution of the plume detected by CALIOP is matched by simulations with the TM4 chemistry transport model for an injection height of 248 hPa (˜10 km). Injection heights at the surface and at 540 hPa (˜5 km) resulted in simulated vertical distributions that were 2-3 km too low relative to CALIOP observations and showed less agreement with the AAI patterns. The high injection altitude of 10 km mimics the effect of pyro-convective lofting as the additional buoyancy from the intense fires is not accounted for in the model. TM4 simulations with an inert and a water-soluble tracer reproduce the observed dilution of the plume and show that the latter gives the best agreement with the observations, suggesting that

  17. Soldiers and marksmen under fire: monitoring performance with neural correlates of small arms fire localization

    PubMed Central

    Sherwin, Jason; Gaston, Jeremy

    2013-01-01

    Important decisions in the heat of battle occur rapidly and a key aptitude of a good combat soldier is the ability to determine whether he is under fire. This rapid decision requires the soldier to make a judgment in a fraction of a second, based on a barrage of multisensory cues coming from multiple modalities. The present study uses an oddball paradigm to examine listener ability to differentiate shooter locations from audio recordings of small arms fire. More importantly, we address the neural correlates involved in this rapid decision process by employing single-trial analysis of electroencephalography (EEG). In particular, we examine small arms expert listeners as they differentiate the sounds of small arms firing events recorded at different observer positions relative to a shooter. Using signal detection theory, we find clear neural signatures related to shooter firing angle by identifying the times of neural discrimination on a trial-to-trial basis. Similar to previous results in oddball experiments, we find common windows relative to the response and the stimulus when neural activity discriminates between target stimuli (forward fire: observer 0° to firing angle) vs. standards (off-axis fire: observer 90° to firing angle). We also find, using windows of maximum discrimination, that auditory target vs. standard discrimination yields neural sources in Brodmann Area 19 (BA 19), i.e., in the visual cortex. In summary, we show that single-trial analysis of EEG yields informative scalp distributions and source current localization of discriminating activity when the small arms experts discriminate between forward and off-axis fire observer positions. Furthermore, this perceptual decision implicates brain regions involved in visual processing, even though the task is purely auditory. Finally, we utilize these techniques to quantify the level of expertise in these subjects for the chosen task, having implications for human performance monitoring in combat. PMID

  18. Pantoea applied genomics to understand and improve biocontrol activity against fire blight

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pantoea agglomerans and P. vagans (ex. Erwinia herbicola) are common epiphytes of pome fruit flowers and three strains (E325, P10c, C9-1) have been commercially developed as effective biocontrol products for managing fire blight (Erwinia amylovora). Antibiotics as a standard, reliable chemical optio...

  19. Green leaf volatiles, fire and nonanoic acid activate MAPkinases in the model grass species Lolium temulentum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Forage and turf related grasses are utilized in diverse environments where they are routinely subjected to herbicides and exposed to fire and volatiles after cutting, however very little is known concerning the perception or molecular responses to these different stresses or compounds. In the model ...

  20. Libby South Fire, Washington

    NASA Technical Reports Server (NTRS)

    2002-01-01

    On July 9, 2001, a fire burned about 15 miles south of Twisp, Washington, that officials believe was caused by human error. NASA's Moderate-resolution Imaging Spectroradiometer on the Terra satellite observed the fire, indicated with a red dot in this image, on July 10, after the fire had already consumed about 1,240 acres. On July 10, another fire-called the Thirty Mile Fire-trapped 21 firefighters and 2 civilians in a narrow canyon in the Chewuch River Valley, north of Winthrop, WA. (That fire did not erupt until later in the day after this image was acquired and is therefore not visible.) Tragically, four firefighters were killed and six people were injured, including the two civilians. Rolling debris, rugged and steep terrain, and limited access are impeding efforts to contain the now 8,200-acre fire, which according to current fire incident reports, is completely uncontained. Nearly all the areas in the full-size image, including Washington (center), Idaho (right), Oregon (bottom) are in a state of severe drought, which means the region could be in for another devastating fire season. Another fire is visible in Idaho in the full-size image just east of where Idaho borders with Washington and Oregon. Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team

  1. Larch Forests of Middle Siberia: Long-Term Trends in Fire Return Intervals

    NASA Technical Reports Server (NTRS)

    Kharuk, Viacheslav I.; Dvinskaya, Mariya L.; Petrov, Ilya A.; Im, Sergei T.; Ranson, Kenneth J.

    2016-01-01

    Fire history within the northern larch forests of Central Siberia was studied (65+degN). Fires within this area are predominantly caused by lightning strikes rather than human activity. Mean fire return intervals (FRIs) were found to be 112 +/- 49 years (based on firescars) and 106 +/- 36 years (based on firescars and tree natality dates). FRIs were increased with latitude increase and observed to be about 80 years at 64N, about 200 years near the Arctic Circle and about 300 years nearby the northern range limit of larch stands (approx.71+degN). Northward FRIs increase correlated with incoming solar radiation (r = -0.95). Post- Little Ice Age (LIA) warming (after 1850) caused approximately a doubling of fire events (in comparison with a similar period during LIA). The data obtained support a hypothesis of climate-induced fire frequency increase. Keywords Fire ecology Fire history Fire frequency Siberian wildfires Larch forests Climate change

  2. Amazon Forest Responses to Drought and Fire

    NASA Astrophysics Data System (ADS)

    Morton, D. C.

    2015-12-01

    Deforestation and agricultural land uses provide a consistent source of ignitions along the Amazon frontier during the dry season. The risk of understory fires in Amazon forests is amplified by drought conditions, when fires at the forest edge may spread for weeks before rains begin. Fire activity also impacts the regional response of intact forests to drought through diffuse light effects and nutrient redistribution, highlighting the complexity of feedbacks in this coupled human and natural system. This talk will focus on recent advances in our understanding of fire-climate feedbacks in the Amazon, building on research themes initiated under NASA's Large-scale Biosphere-Atmosphere Experiment in Amazonia (LBA). NASA's LBA program began in the wake of the 1997-1998 El Niño, a strong event that exposed the vulnerability of Amazon forests to drought and fire under current climate and projections of climate change. With forecasts of another strong El Niño event in 2015-2016, this talk will provide a multi-scale synthesis of Amazon forest responses to drought and fire based on field measurements, airborne lidar data, and satellite observations of fires, rainfall, and terrestrial water storage. These studies offer new insights into the mechanisms governing fire season severity in the southern Amazon and regional variability in carbon losses from understory fires. The contributions from remote sensing to our understanding of drought and fire in Amazon forests reflect the legacy of NASA's LBA program and the sustained commitment to interdisciplinary research across the Amazon region.

  3. Forest fire danger index based on modifying Nesterov Index, fuel, and anthropogenic activities using MODIS TERRA, AQUA and TRMM satellite datasets

    NASA Astrophysics Data System (ADS)

    Suresh Babu, K. V.; Roy, Arijit; Ramachandra Prasad, P.

    2016-05-01

    Forest fire has been regarded as one of the major causes of degradation of Himalayan forests in Uttarakhand. Forest fires occur annually in more than 50% of forests in Uttarakhand state, mostly due to anthropogenic activities and spreads due to moisture conditions and type of forest fuels. Empirical drought indices such as Keetch-Byram drought index, the Nesterov index, Modified Nesterov index, the Zhdanko index which belongs to the cumulative type and the Angstrom Index which belongs to the daily type have been used throughout the world to assess the potential fire danger. In this study, the forest fire danger index has been developed from slightly modified Nesterov index, fuel and anthropogenic activities. Datasets such as MODIS TERRA Land Surface Temperature and emissivity (MOD11A1), MODIS AQUA Atmospheric profile product (MYD07) have been used to determine the dew point temperature and land surface temperature. Precipitation coefficient has been computed from Tropical Rainfall measuring Mission (TRMM) product (3B42RT). Nesterov index has been slightly modified according to the Indian context and computed using land surface temperature, dew point temperature and precipitation coefficient. Fuel type danger index has been derived from forest type map of ISRO based on historical fire location information and disturbance danger index has been derived from disturbance map of ISRO. Finally, forest fire danger index has been developed from the above mentioned indices and MODIS Thermal anomaly product (MOD14) has been used for validating the forest fire danger index.

  4. Fighting Fire with Fire.

    ERIC Educational Resources Information Center

    Spoor, Dana L.

    1996-01-01

    School districts are integrating security and life-safety systems into school buildings to protect students and property. This proactive approach includes sprinkler systems, fire alarms, and security systems that monitor door movement. Some school districts that are incorporating the latest life-safety technology are in Missouri, Ohio, California,…

  5. Spatiotemporal patterns of tundra fires: late-Quaternary charcoal records from Alaska

    NASA Astrophysics Data System (ADS)

    Chipman, M. L.; Hudspith, V.; Higuera, P. E.; Duffy, P. A.; Kelly, R.; Oswald, W. W.; Hu, F. S.

    2015-02-01

    Anthropogenic climate change has altered many ecosystem processes in the Arctic tundra and may have resulted in unprecedented fire activity. Evaluating the significance of recent fires requires knowledge from the paleo-fire record because observational data in the Arctic span only several decades, much shorter than the natural fire rotation in Arctic tundra regions. Here we report results of charcoal analysis on lake sediments from four Alaskan lakes to infer the broad spatial and temporal patterns of tundra fire occurrence over the past 35 000 years. Background charcoal accumulation rates are low in all records (range = 0-0.05 pieces cm-2 year-1), suggesting minimal biomass burning across our study areas. Charcoal peak analysis reveals that the mean fire return interval (FRI; years between consecutive fire events) ranged from 1648 to 6045 years at our sites, and that the most recent fire events occurred from 882 to 7031 years ago, except for the CE 2007 Anaktuvuk River Fire. These mean FRI estimates are longer than the fire rotation periods estimated for the past 63 years in the areas surrounding three of the four study lakes. This result suggests that the frequency of tundra burning was higher over the recent past compared to the late Quaternary in some tundra regions. However, the ranges of FRI estimates from our paleo-fire records overlap with the expected values based on fire-rotation-period estimates from the observational fire data, and thus quantitative differences are not significant. Together with previous tundra-fire reconstructions, these data suggest that the rate of tundra burning was spatially variable and that fires were extremely rare in our study areas throughout the late Quaternary. Given the rarity of tundra burning over multiple millennia in our study areas and the pronounced effects of fire on tundra ecosystem processes such as carbon cycling, dramatic tundra ecosystem changes are expected if anthropogenic climate change leads to more frequent

  6. Dynamics of vegetation and soils of oak/saw palmetto scrub after fire: Observations from permanent transects

    NASA Technical Reports Server (NTRS)

    Schmalzer, Paul A.; Hinkle, G. Ross

    1991-01-01

    Ten permanent 15 m transects previously established in two oak/saw palmetto scrub stands burned in December 1986, while two transects remained unburned. Vegetation in the greater than 0.5 m and the less than 0.5 m layers on these transects was sampled at 6, 12, 18, 24, and 36 months postburn and determined structural features of the vegetation (height, percent bare ground, total cover). The vegetation data were analyzed from each sampling by height layer using detrended correspondence analysis ordination. Vegetation data for the greater than 0.5 m layer for the entire time sequence were combined and analyzed using detrended correspondence analysis ordination. Soils were sampled at 6, 12, 18, and 24 months postburn and analyzed for pH, conductivity, organic matter, exchangeable cations (Ca, Mg, K, Na), NO3-N, NH4-N, Al, available metals (Cu, Fe, Mn, Zn), and PO4-P. Shrub species recovered at different rates postfire with saw palmetto reestablishing cover greater than 0.5 m within one year, but the scrub oaks had not returned to preburn cover greater than 0.5 m in 3 years after the fire. These differences in growth rates resulted in dominance shifts after the fire with saw palmetto increasing relative to the scrub oaks. Overall changes in species richness were minor, although changes occurred in species richness by height layers due to different growth rates. Soils of well drained and poorly drained sites differed markedly. Soil responses to the fire appeared minor. Soil pH increased at 6 and 12 months postfire; calcium increased at 6 months postburn. Nitrate-nitrogen increased at 12 months postburn. Low values of conductivity, PO4-P, Mg, K, Na, and Fe at 12 months postburn may be related to heavy rainfall the preceding month. Seasonal variability in some soil parameters appeared to occur.

  7. Soil microbiological properties and enzymatic activities of long-term post-fire recovery in dry and semiarid Aleppo pine (Pinus halepensis M.) forest stands

    NASA Astrophysics Data System (ADS)

    Hedo, J.; Lucas-Borja, M. E.; Wic, C.; Andrés-Abellán, M.; de Las Heras, J.

    2015-02-01

    Wildfires affecting forest ecosystems and post-fire silvicultural treatments may cause considerable changes in soil properties. The capacity of different microbial groups to recolonise soil after disturbances is crucial for proper soil functioning. The aim of this work was to investigate some microbial soil properties and enzyme activities in semiarid and dry Aleppo pine (Pinus halepensis M.) forest stands. Different plots affected by a wildfire event 17 years ago without or with post-fire silvicultural treatments 5 years after the fire event were selected. A mature Aleppo pine stand, unaffected by wildfire and not thinned was used as a control. Physicochemical soil properties (soil texture, pH, carbonates, organic matter, electrical conductivity, total N and P), soil enzymes (urease, phosphatase, β-glucosidase and dehydrogenase activities), soil respiration and soil microbial biomass carbon were analysed in the selected forests areas and plots. The main finding was that long time after this fire event produces no differences in the microbiological soil properties and enzyme activities of soil after comparing burned and thinned, burned and not thinned, and mature plots. Moreover, significant site variation was generally seen in soil enzyme activities and microbiological parameters. We conclude that total vegetation recovery normalises post-fire soil microbial parameters, and that wildfire and post-fire silvicultural treatments are not significant factors affecting soil properties after 17 years.

  8. Observational methods used to assess rat behavior: general activity.

    PubMed

    Paul, Carol Ann; Beltz, Barbara; Berger-Sweeney, Joanne

    2007-09-01

    INTRODUCTIONThe activity-inactivity continuum is an important parameter of behavior, and quantification of overall locomotor activity in the rat should identify it as a naturally nocturnal animal. Disruptions in nocturnal activity can be caused by damage in visual inputs to the brain or damage in the hypothalamus. Many commercial devices are available to measure activity automatically; some can be integrated with a computer to allow overnight monitoring in the absence of an observer. A less sophisticated but still accurate method of measuring activity is to create a home-made activity chamber by replacing the bottom of a box with Plexiglas or by marking lines on the bottom of a clean rat cage so that the observer can record rat activity by noting when the lines are crossed, while simultaneously recording other behaviors. Activity in rat pups can be observed as soon as they are 10 days old using smaller activity chambers. This protocol describes the construction of a home-made activity chamber and how to measure four activities: locomotion, rearing, circling, and grooming.

  9. Estimation of Fire Radiative Energy in Siberia Using MODIS Data

    NASA Astrophysics Data System (ADS)

    Shvetsov, Eugene; Ponomarev, Evgenii

    2014-05-01

    The intensity of heat release during biomass combustion is an important characteristic of wildfires. Space-borne systems, such as MODIS radiometer, provide observations of fire locations, as well as an estimate of the amount of radiant energy emitted by the fire. Such measures of fire radiative power (FRP) provide information on the fireline heat release intensity and on the rate of biomass combustion in large scale and are important for the analysis of fire impact on vegetation. In this study we analyzed the spatial distribution and temporal dynamics of detected wildfires in Siberia considering their radiative power. For the analysis we used database of fire detections made by MODIS instrument located on TERRA and AQUA satellites for 2002- 2013. For the detected fire pixels the frequency of their occurrence was calculated depending on the radiative power. More than 80% of all detected pixels had radiative power less than 100 MW. The distribution of fires according to their radiative power values was obtained for different regions of Siberia characterized by various vegetation and climatic conditions. Geospatial analysis performed using vegetation maps for the territory of Siberia and GIS layers of active fire detections showed that fires in deciduous and pine forests generally had lower intensities than fires in larch and spruce/fir forests. The rate of biomass combustion and the amount of heat emitted are strongly related to fuel moisture and therefore to weather conditions. In this study weather conditions were characterized using Russian and Canadian weather fire danger indices. Using images obtained during day and night satellite passes daily and long-term dynamics of fire radiative power was calculated. The long-term dynamics of fire radiative power measured by MODIS sensor was compared to weather fire danger indices calculated using on-ground weather stations data located in several Siberian regions mostly liable to fires. For most of the weather stations

  10. Fire in the Earth System: A deep time perspective

    NASA Astrophysics Data System (ADS)

    Scott, Andrew C.; Glasspool, Ian J.; Bond, William J.; Collinson, Margaret E.

    2010-05-01

    angiosperms. Early angiosperms were predominantly herbaceous and appear to have favoured disturbed habitats. As has been noted fires were frequent during this interval and represents a major ecological disturbance factor. A large proportion of our understanding of early angiosperm evolution comes from charcoalified flowers. This is also the case with C4 grasslands where fire appears to be a major contributor to their success. However, we observe a decrease in fire activity from the mid-Eocene onwards, especially in wetland habitats and we note especially the evolution of a more modern tropical rainforest structure that does not promote fire.

  11. Dose- and Rate-Dependent Effects of Cocaine on Striatal Firing Related to Licking

    PubMed Central

    Tang, Chengke; Mittler, Taliah; Duke, Dawn C.; Zhu, Yun; Pawlak, Anthony P.; West, Mark O.

    2011-01-01

    To examine the role of striatal mechanisms in cocaine-induced stereotyped licking, we investigated the acute effects of cocaine on striatal neurons in awake, freely moving rats before and after cocaine administration (0, 5, 10, or 20 mg/kg). Stereotyped licking was induced only by the high dose. Relative to control (saline), cocaine reduced lick duration and concurrently increased interlick interval, particularly at the high dose, but it did not affect licking rhythm. Firing rates of striatal neurons phasically related to licking movements were compared between matched licks before and after injection, minimizing any influence of sensorimotor variables on changes in firing. Both increases and decreases in average firing rate of striatal neurons were observed after cocaine injection, and these changes exhibited a dose-dependent pattern that strongly depended on predrug firing rate. At the middle and high doses relative to the saline group, the average firing rates of slow firing neurons were increased by cocaine, resulting from a general elevation of movement-related firing rates. In contrast, fast firing neurons showed decreased average firing rates only in the high-dose group, with reduced firing rates across the entire range for these neurons. Our findings suggest that at the high dose, increased phasic activity of slow firing striatal neurons and simultaneously reduced phasic activity of fast firing striatal neurons may contribute, respectively, to the continual initiation of stereotypic movements and the absence of longer movements. PMID:17991811

  12. Talking Fire Alarms Calm Kids.

    ERIC Educational Resources Information Center

    Executive Educator, 1984

    1984-01-01

    The new microprocessor-based fire alarm systems can help to control smoke movement throughout school buildings by opening vents and doors, identify the burning section, activate voice alarms, provide firefighters with telephone systems during the fire, and release fire-preventing gas. (KS)

  13. A hydroclimatic model of global fire patterns

    NASA Astrophysics Data System (ADS)

    Boer, Matthias

    2015-04-01

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

  14. Fire investigation

    NASA Astrophysics Data System (ADS)

    Gomberg, A.

    There was considerable progress made on several fronts of fire investigation in the United States in recent years. Progress was made in increasing the quantity of fire investigation and reporting, through efforts to develop the National Fire Incident Reporting System. Improving overall quality of fire investigation is the objective of efforts such as the Fire Investigation Handbook, which was developed and published by the National Bureau of Standards, and the upgrading and expanding of the ""dictionary'' of fire investigation and reporting, the NFPA 901, Uniform Coding for Fire Protection, system. The science of fire investigation as furthered also by new approaches to post fire interviews being developed at the University of Washington, and by in-depth research into factors involved in several large loss fires, including the MGM Grand Hotel in Las Vegas. Finally, the use of special study fire investigations - in-depth investigations concentrating on specific fire problems - is producing new glimpses into the nature of the national fire problem. A brief description of the status of efforts in each of these areas is discussed.

  15. Conservation threats due to human-caused increases in fire frequency in Mediterranean-climate ecosystems.

    PubMed

    Syphard, Alexandra D; Radeloff, Volker C; Hawbaker, Todd J; Stewart, Susan I

    2009-06-01

    Periodic wildfire is an important natural process in Mediterranean-climate ecosystems, but increasing fire recurrence threatens the fragile ecology of these regions. Because most fires are human-caused, we investigated how human population patterns affect fire frequency. Prior research in California suggests the relationship between population density and fire frequency is not linear. There are few human ignitions in areas with low population density, so fire frequency is low. As population density increases, human ignitions and fire frequency also increase, but beyond a density threshold, the relationship becomes negative as fuels become sparser and fire suppression resources are concentrated. We tested whether this hypothesis also applies to the other Mediterranean-climate ecosystems of the world. We used global satellite databases of population, fire activity, and land cover to evaluate the spatial relationship between humans and fire in the world's five Mediterranean-climate ecosystems. Both the mean and median population densities were consistently and substantially higher in areas with than without fire, but fire again peaked at intermediate population densities, which suggests that the spatial relationship is complex and nonlinear. Some land-cover types burned more frequently than expected, but no systematic differences were observed across the five regions. The consistent association between higher population densities and fire suggests that regardless of differences between land-cover types, natural fire regimes, or overall population, the presence of people in Mediterranean-climate regions strongly affects the frequency of fires; thus, population growth in areas now sparsely settled presents a conservation concern. Considering the sensitivity of plant species to repeated burning and the global conservation significance of Mediterranean-climate ecosystems, conservation planning needs to consider the human influence on fire frequency. Fine-scale spatial

  16. Pinus contorta invasions increase wildfire fuel loads and may create a positive feedback with fire.

    PubMed

    Taylor, Kimberley T; Maxwell, Bruce D; McWethy, David B; Pauchard, Aníbal; Nuñez, Martín A; Whitlock, Cathy

    2017-03-01

    Invasive plant species that have the potential to alter fire regimes have significant impacts on native ecosystems. Concern that pine invasions in the Southern Hemisphere will increase fire activity and severity and subsequently promote further pine invasion prompted us to examine the potential for feedbacks between Pinus contorta invasions and fire in Patagonia and New Zealand. We determined how fuel loads and fire effects were altered by P. contorta invasion. We also examined post-fire plant communities across invasion gradients at a subset of sites to assess how invasion alters the post-fire vegetation trajectory. We found that fuel loads and soil heating during simulated fire increase with increasing P. contorta invasion age or density at all sites. However, P. contorta density did not always increase post-fire. In the largest fire, P. contorta density only increased significantly post-fire where the pre-fire P. contorta density was above an invasion threshold. Below this threshold, P. contorta did not dominate after fire and plant communities responded to fire in a similar manner as uninvaded communities. The positive feedback observed at high densities is caused by the accumulation of fuel that in turn results in greater soil heating during fires and high P. contorta density post-fire. Therefore, a positive feedback may form between P. contorta invasions and fire, but only above an invasion density threshold. These results suggest that management of pine invasions before they reach the invasion density threshold is important for reducing fire risk and preventing a transition to an alternate ecosystem state dominated by pines and novel understory plant communities.

  17. The role of fire in the boreal carbon budget

    USGS Publications Warehouse

    Harden, J.W.; Trumbore, S.E.; Stocks, B.J.; Hirsch, A.; Gower, S.T.; O'Neill, K. P.; Kasischke, E.S.

    2000-01-01

    To reconcile observations of decomposition rates, carbon inventories, and net primary production (NPP), we estimated long-term averages for C exchange in boreal forests near Thompson, Manitoba. Soil drainage as defined by water table, moss cover, and permafrost dynamics, is the dominant control on direct fire emissions. In upland forests, an average of about 10-30% of annual NPP was likely consumed by fire over the past 6500 years since these landforms and ecosystems were established. This long-term, average fire emission is much larger than has been accounted for in global C cycle models and may forecast an increase in fire activity for this region. While over decadal to century times these boreal forests may be acting as slight net sinks for C from the atmosphere to land, periods of drought and severe fire activity may result in net sources of C from these systems.

  18. Fire-probability maps for the Brazilian Amazonia

    NASA Astrophysics Data System (ADS)

    Cardoso, Manoel; Sampaio, Gilvan; Obregon, Guillermo; Nobre, Carlos

    2010-05-01

    Most fires in Amazonia result from the combination between climate and land-use factors. They occur mainly in the dry season and are used as an inexpensive tool for land clearing and management. However, their unintended consequences are of important concern. Fire emissions are the most important sources of greenhouse gases and aerosols in the region, accidental fires are a major threat to protected areas, and frequent fires may lead to permanent conversion of forest areas into savannas. Fire-activity models have thus become important tools for environmental analyses in Amazonia. They are used, for example, in warning systems for monitoring the risk of burnings in protected areas, to improve the description of biogeochemical cycles and vegetation composition in ecosystem models, and to help estimate the long-term potential for savannas in biome models. Previous modeling studies for the whole region were produced in units of satellite fire pixels, which complicate their direct use for environmental applications. By reinterpreting remote-sensing based data using a statistical approach, we were able to calibrate models for the whole region in units of probability, or chance of fires to occur. The application of these models for years 2005 and 2006 provided maps of fire potential at 3-month and 0.25-deg resolution as a function of precipitation and distance from main roads. In both years, the performance of the resulting maps was better for the period July-September. During these months, most of satellite-based fire observations were located in areas with relatively high chance of fire, as determined by the modeled probability maps. In addition to reproduce reasonably well the areas presenting maximum fire activity as detected by remote sensing, the new results in units of probability are easier to apply than previous estimates from fire-pixel models.

  19. Fire-probability maps for the Brazilian Amazonia

    NASA Astrophysics Data System (ADS)

    Cardoso, M.; Nobre, C.; Obregon, G.; Sampaio, G.

    2009-04-01

    Most fires in Amazonia result from the combination between climate and land-use factors. They occur mainly in the dry season and are used as an inexpensive tool for land clearing and management. However, their unintended consequences are of important concern. Fire emissions are the most important sources of greenhouse gases and aerosols in the region, accidental fires are a major threat to protected areas, and frequent fires may lead to permanent conversion of forest areas into savannas. Fire-activity models have thus become important tools for environmental analyses in Amazonia. They are used, for example, in warning systems for monitoring the risk of burnings in protected areas, to improve the description of biogeochemical cycles and vegetation composition in ecosystem models, and to help estimate the long-term potential for savannas in biome models. Previous modeling studies for the whole region were produced in units of satellite fire pixels, which complicate their direct use for environmental applications. By reinterpreting remote-sensing based data using a statistical approach, we were able to calibrate models for the whole region in units of probability, or chance of fires to occur. The application of these models for years 2005 and 2006 provided maps of fire potential at 3-month and 0.25-deg resolution as a function of precipitation and distance from main roads. In both years, the performance of the resulting maps was better for the period July-September. During these months, most of satellite-based fire observations were located in areas with relatively high chance of fire, as determined by the modeled probability maps. In addition to reproduce reasonably well the areas presenting maximum fire activity as detected by remote sensing, the new results in units of probability are easier to apply than previous estimates from fire-pixel models.

  20. Dynamics, Patterns and Causes of Fires in Northwestern Amazonia

    PubMed Central

    Armenteras, Dolors; Retana, Javier

    2012-01-01

    According to recent studies, two widespread droughts occurred in the Amazon basin, one during 2005 and one during 2010. The drought increased the prevalence of climate-driven fires over most of the basin. Given the importance of human-atmosphere-vegetation interactions in tropical rainforests, these events have generated concerns over the vulnerability of this area to climate change. This paper focuses on one of the wettest areas of the basin, Northwestern Amazonia, where the interactions between the climate and fires are much weaker and where little is known about the anthropogenic drivers of fires. We have assessed the response of fires to climate over a ten-year period, and analysed the socio-economic and demographic determinants of fire occurrence. The patterns of fires and climate and their linkages in Northwestern Amazonia differ from the enhanced fire response to climate variation observed in the rest of Amazonia. The highest number of recorded fires in Northwestern Amazonia occurred in 2004 and 2007, and this did not coincide with the periods of extreme drought experienced in Amazonia in 2005 and 2010. Rather, during those years, Northwestern Amazonia experienced a relatively small numbers of fire hotspots. We have shown that fire occurrence correlated well with deforestation and was determined by anthropogenic drivers, mainly small-scale agriculture, cattle ranching (i.e., pastures) and active agricultural frontiers (including illegal crops). Thus, the particular climatic conditions for air convergence and rainfall created by proximity to the Andes, coupled with the presence of one of the most active colonisation fronts in the region, make this region differently affected by the general drought-induced fire patterns experienced by the rest of the Amazon. Moreover, the results suggest that, even in this wet region, humans are able to modify the frequency of fires and impact these historically well preserved forests. PMID:22523580

  1. Dynamics, patterns and causes of fires in Northwestern Amazonia.

    PubMed

    Armenteras, Dolors; Retana, Javier

    2012-01-01

    According to recent studies, two widespread droughts occurred in the Amazon basin, one during 2005 and one during 2010. The drought increased the prevalence of climate-driven fires over most of the basin. Given the importance of human-atmosphere-vegetation interactions in tropical rainforests, these events have generated concerns over the vulnerability of this area to climate change. This paper focuses on one of the wettest areas of the basin, Northwestern Amazonia, where the interactions between the climate and fires are much weaker and where little is known about the anthropogenic drivers of fires. We have assessed the response of fires to climate over a ten-year period, and analysed the socio-economic and demographic determinants of fire occurrence. The patterns of fires and climate and their linkages in Northwestern Amazonia differ from the enhanced fire response to climate variation observed in the rest of Amazonia. The highest number of recorded fires in Northwestern Amazonia occurred in 2004 and 2007, and this did not coincide with the periods of extreme drought experienced in Amazonia in 2005 and 2010. Rather, during those years, Northwestern Amazonia experienced a relatively small numbers of fire hotspots. We have shown that fire occurrence correlated well with deforestation and was determined by anthropogenic drivers, mainly small-scale agriculture, cattle ranching (i.e., pastures) and active agricultural frontiers (including illegal crops). Thus, the particular climatic conditions for air convergence and rainfall created by proximity to the Andes, coupled with the presence of one of the most active colonisation fronts in the region, make this region differently affected by the general drought-induced fire patterns experienced by the rest of the Amazon. Moreover, the results suggest that, even in this wet region, humans are able to modify the frequency of fires and impact these historically well preserved forests.

  2. Kv3.1/Kv3.2 channel positive modulators enable faster activating kinetics and increase firing frequency in fast-spiking GABAergic interneurons.

    PubMed

    Boddum, Kim; Hougaard, Charlotte; Xiao-Ying Lin, Julie; von Schoubye, Nadia Lybøl; Jensen, Henrik Sindal; Grunnet, Morten; Jespersen, Thomas

    2017-02-24

    Due to their fast kinetic properties, Kv3.1 voltage gated potassium channels are important in setting and controlling firing frequency in neurons and pivotal in generating high frequency firing of interneurons. Pharmacological activation of Kv3.1 channels may possess therapeutic potential for treatment of epilepsy, hearing disorders, schizophrenia and cognitive impairments. Here we thoroughly investigate the selectivity and positive modulation of the two small molecules, EX15 and RE01, on Kv3 channels. Selectivity studies, conducted in Xenopus laevis oocytes confirmed a positive modulatory effect of the two compounds on Kv3.1 and to a minor extent on Kv3.2 channels. RE01 had no effect on the Kv3.3 and Kv3.4 channels, whereas EX15 had an inhibitory impact on the Kv3.4 mediated current. Voltage-clamp experiments in monoclonal hKv3.1b/HEK293 cells (34 °C) revealed that the two compounds indeed induced larger currents and faster activation kinetics. They also decrease the speed of deactivation and shifted the voltage dependence of activation, to a more negative activation threshold. Application of action potential clamping and repetitive stimulation protocols of hKv3.1b expressing HEK293 cells revealed that EX15 and RE01 significantly increased peak amplitude, half width and decay time of Kv3.1 mediated currents, even during high-frequency action potential clamping (250 Hz). In rat hippocampal slices, EX15 and RE01 increased neuronal excitability in fast-spiking interneurons in dentate gyrus. Action potential frequency was prominently increased at minor depolarizing steps, whereas more marginal effects of EX15 and RE01 were observed after stronger depolarizations. In conclusion, our results suggest that EX15 and RE01 positive modulation of Kv3.1 and Kv3.2 currents facilitate increased firing frequency in fast-spiking GABAergic interneurons.

  3. Developmental Changes in Hippocampal CA1 Single Neuron Firing and Theta Activity during Associative Learning

    PubMed Central

    Kim, Jangjin; Goldsberry, Mary E.; Harmon, Thomas C.; Freeman, John H.

    2016-01-01

    Hippocampal development is thought to play a crucial role in the emergence of many forms of learning and memory, but ontogenetic changes in hippocampal activity during learning have not been examined thoroughly. We examined the ontogeny of hippocampal function by recording theta and single neuron activity from the dorsal hippocampal CA1 area while rat pups were trained in associative learning. Three different age groups [postnatal days (P)17-19, P21-23, and P24-26] were trained over six sessions using a tone conditioned stimulus (CS) and a periorbital stimulation unconditioned stimulus (US). Learning increased as a function of age, with the P21-23 and P24-26 groups learning faster than the P17-19 group. Age- and learning-related changes in both theta and single neuron activity were observed. CA1 pyramidal cells in the older age groups showed greater task-related activity than the P17-19 group during CS-US paired sessions. The proportion of trials with a significant theta (4–10 Hz) power change, the theta/delta ratio, and theta peak frequency also increased in an age-dependent manner. Finally, spike/theta phase-locking during the CS showed an age-related increase. The findings indicate substantial developmental changes in dorsal hippocampal function that may play a role in the ontogeny of learning and memory. PMID:27764172

  4. Variation in soil enzyme activity as a function of vegetation amount, type, and spatial structure in fire-prone Mediterranean shrublands.

    PubMed

    Mayor, Ángeles G; Goirán, Silvana B; Vallejo, V Ramón; Bautista, Susana

    2016-12-15

    Fire-prone Mediterranean shrublands may be seriously threatened by land degradation due to progressive opening of the vegetation cover driven by increasing drought and fire recurrence. However, information about the consequences of this opening process for critical ecosystem functions is scant. In this work, we studied the influence of vegetation amount, type, and spatial pattern in the variation of extracellular soil enzyme activity (acid phosphatase, β-glucosidase, and urease) in fire-prone shrublands in eastern Spain. Soil was sampled in vegetation-patch and open-interpatch microsites in 15 shrubland sites affected by large wildfires in 1991. On average, the activities of the three enzymes were 1.5 (β-glucosidase and urease) to 1.7 (acid phosphatase) times higher in soils under vegetation patches than in adjacent interpatches. In addition, phosphatase activity for both microsites significantly decreased with the fragmentation of the vegetation. This result was attributed to a lower influence of roots -the main source of acid phosphatase- in the bigger interpatches of the sites with lower patch cover, and to feedbacks between vegetation pattern, redistribution of resources, and soil quality during post-fire vegetation dynamics. Phosphatase activity was also 1.2 times higher in patches of resprouter plants than in patches of non-resprouters, probably due to the faster post-fire recovery and older age of resprouter patches in these fire-prone ecosystems. The influence on the studied enzymes of topographic and climatic factors acting at the landscape scale was insignificant. According to our results, variations in the cover, pattern, and composition of vegetation patches may have profound impacts on soil enzyme activity and associated nutrient cycling processes in fire-prone Mediterranean shrublands, particularly in those related to phosphorus.

  5. Fire ants

    MedlinePlus

    ... please enable JavaScript. Fire ants are red-colored insects. A sting from a fire ant delivers a ... poison control. Those who have an allergy to insect bites or stings should carry a bee sting ...

  6. Understory Fires

    NASA Video Gallery

    The flames of understory fires in the southern Amazon reach on average only a few feet tall, but the fire type can claim anywhere from 10 to 50 percent of a burn area's trees. Credit: NASA/Doug Morton

  7. Less wiring, more firing: low-performing older adults compensate for impaired white matter with greater neural activity.

    PubMed

    Daselaar, Sander M; Iyengar, Vijeth; Davis, Simon W; Eklund, Karl; Hayes, Scott M; Cabeza, Roberto E

    2015-04-01

    The reliable neuroimaging finding that older adults often show greater activity (over-recruitment) than younger adults is typically attributed to compensation. Yet, the neural mechanisms of over-recruitment in older adults (OAs) are largely unknown. Rodent electrophysiology studies have shown that as number of afferent fibers within a circuit decreases with age, the fibers that remain show higher synaptic field potentials (less wiring, more firing). Extrapolating to system-level measures in humans, we proposed and tested the hypothesis that greater activity in OAs compensates for impaired white-matter connectivity. Using a neuropsychological test battery, we measured individual differences in executive functions associated with the prefrontal cortex (PFC) and memory functions associated with the medial temporal lobes (MTLs). Using event-related functional magnetic resonance imaging, we compared activity for successful versus unsuccessful trials during a source memory task. Finally, we measured white-matter integrity using diffusion tensor imaging. The study yielded 3 main findings. First, low-executive OAs showed greater success-related activity in the PFC, whereas low-memory OAs showed greater success-related activity in the MTLs. Second, low-executive OAs displayed white-matter deficits in the PFC, whereas low-memory OAs displayed white-matter deficits in the MTLs. Finally, in both prefrontal and MTL regions, white-matter decline and success-related activations occurred in close proximity and were negatively correlated. This finding supports the less-wiring-more-firing hypothesis, which provides a testable account of compensatory over-recruitment in OAs.

  8. Interprofessional pharmacy observation activity for third-year dental students.

    PubMed

    Conway, Susan E; Smith, Winter J; Truong, Teresa H; Shadid, Jill

    2014-09-01

    Interprofessional learning is a key component of today's health sciences education. Within a two-course series in dental pharmacology and therapeutics, a dental curriculum was revised to provide an interprofessional activity to expose dental students to a community pharmacy setting. The objectives of this activity were to augment students' learning about drug laws and prescription writing, as well as to foster interprofessional relationships and collaboration between pharmacists and dentists. Dental students were scheduled for one-hour observations at community pharmacies on campus. Learning objectives to guide this activity focused on demonstrating community pharmacy operating procedures, identifying ways to minimize prescribing and dosing errors, and understanding how pharmacists can assist dentists in prescribing. Following the observation, students were required to submit a written assignment, which accounted for 14 percent of their course grade. All 119 dental students (100 percent) enrolled in the course for the summers of 2012 and 2013 completed the activity. The average grade on the written assignment was 96.2 out of 100. At the end of the course, students were asked to participate in an online course evaluation survey, for which response rates were 37 percent and 43 percent for 2012 and 2013, respectively. The students rated the pharmacy observation activity favorably on this course evaluation. The pharmacy observation activity provided a successful interprofessional component to the didactic pharmacy course and was well received by the dental students as well as the community pharmacists.

  9. Research in fire prevention.

    PubMed

    Pearce, N

    1985-10-01

    This paper describes in broad terms, the fire testing programme we carried out on whole bed assemblies in 1984. It should be clear that the tests were carried out in a thoroughly rigorous scientific manner. As always there is more to be done. The immediate task of finding the so called 'safe' bed assembly is proceeding with the search this year for safer pillows. Softer barrier foams are now being produced and it may be that the NHS could use full depth foam mattresses rather than a barrier foam wrap. On the engineering side I have explained the false alarm problem, and I have reviewed some of the research we are doing to see that new technology is used to give us better systems in future. Life safety sprinkler systems give the possibility of truly active fire protection in patient areas. They will enhance fire safety but at the moment no trade-offs can be offered in other areas of fire protection--either active or passive. My final point is that although I have considered the Department's fire research by looking separately at specific projects, the fire safety of a hospital must always be considered as a total package. To be effective, individual components of fire safety must not be considered in isolation but as part of the overall fire safety system.

  10. Dynamics of active regions observed with Hinode XRT

    NASA Astrophysics Data System (ADS)

    Sakao, Taro

    We present dynamics of active regions observed with the X-Ray Telescope (XRT) aboard Hinode. XRT is a grazing-incidence imager with a Walter Type-I-like mirror of 34 cm diameter with a back-illuminated CCD device. The XRT can image the X-ray corona of the Sun with angular resolution consistent with 1 arcsec CCD pixel size. In addition to this unprecedentedly-high angular resolution ever achieved as a solar X-ray telescope, enhanced sensitivity of the CCD towards longer X-ray wavelengths (particularly beyond 50 Angstroms) enables XRT to image, and perform temperature diagnostics on, a wide range of coronal plasmas from those as low as 1 MK to high-temperature plasmas even exceeding 10 MK. This adds a notable advantage to the XRT such that it can observe most, if not all, active phenomena taking place in and around active regions. Since the beginning of observations with XRT on 23 October 2006, the XRT has so far made various interesting observations regarding active regions. These include (1) continuous outflow of plasmas from the edge of a solar active region that is likely to be a source of (slow) solar wind, (2) clear signature of eruptions for activities even down to GOES B-level, (3) detailed structure and evolution of flaring loops, (4) formation of large-scale hot loops around active regions, and so on. Dynamic phenomena in and around active regions observed with Hinode XRT will be presented and their possible implications to the Sun-Earth connection investigation will be discussed.

  11. Nitrogen oxides and PAN in plumes from boreal fires during ARCTAS-B and their impact on ozone: An integrated analysis of aircraft and satellite observations

    NASA Astrophysics Data System (ADS)

    Alvarado, M. J.; Logan, J. A.; Mao, J.; Apel, E. C.; Riemer, D. D.; Blake, D. R.; Cohen, R. C.; Min, K.; Perring, A. E.; Browne, E. C.; Wooldridge, P. J.; Diskin, G. S.; Sachse, G. W.; Fuelberg, H. E.; Sessions, W.; Harrigan, D. L.; Huey, L. G.; Liao, J.; Case Hanks, A. T.; Jimenez, J. L.; Cubison, M.; Weinheimer, A. J.; Knapp, D. J.; Flocke, F. M.; Wennberg, P. O.; Kuerten, A.; Crounse, J.; St. Clair, J.; Wisthaler, A.; Vay, S. A.; Arctas Science Team

    2010-12-01

    We determine enhancement ratios for NOx , PAN, and other NOy species from boreal biomass burning using aircraft data obtained during the ARCTAS-B campaign and examine the impact of these emissions on tropospheric ozone in the Arctic. We find an initial emission factor for NOx of 1.06 g NO per kg dry matter (DM) burned, one third the value recommended for extratropical fires. Our analysis provides the first observational confirmation of rapid PAN formation in a boreal smoke plume, with 40% of the initial NOx emissions being converted to PAN in the first few hours after emission. We find little clear evidence for ozone formation in the boreal smoke plumes during ARCTAS-B in either aircraft or satellite observations, or in model simulations. Only a third of the smoke plumes observed by the NASA DC8 showed a correlation between ozone and CO, and ozone was depleted in the plumes as often as it was enhanced. Special observations from the Tropospheric Emission Spectrometer (TES) also show little evidence for enhanced ozone in boreal smoke plumes between 15 June and 15 July 2008. Using the GEOS-Chem atmospheric chemistry model, we show that boreal fires during ARCTAS-B had little impact on the median ozone profile measured over Canada, and had little impact on ozone within the smoke plumes observed by TES. We show that the modeled ozone levels are more sensitive to estimates of injection height, total biomass consumed and NOy emission factor than to the initial partitioning of the NOy emissions between NOx and PAN.

  12. AVHRR-based drought-observing system for monitoring the environment and socioeconomic activities

    NASA Astrophysics Data System (ADS)

    Kogan, F.

    From all natural disaster, drought is the least understandable and the most damaging environmental phenomenon. Although in pre-satellite era, climate data were used for drought monitoring, drought specifics created problems in early drought detection start/end, monitoring its expansion/contraction, intensity and area coverage and the most important, timely estimation of the impacts on the environment and socioeconomic activities. The latest prevented to take prompt measures in mitigating negative consequences of drought for the society. Advances in remote sensing of the past ten years, contributed to the development of comprehensive drought monitoring system and numerous applications, which helped to make decisions for monitoring the environment and predicting sustainable socioeconomic activities. This paper discusses satellite-based land-surface observing system, which provides wells of information used for monitoring such unusual natural disaster as drought. This system was developed from the observations of the Advanced Very High Resolution Radiometer (AVHRR) flown on NOAA operational polar-orbiting satellites. The AVHRR data were packed into the Global Vegetation Index (GVI) product, which have served the global community since 1981. The GVI provided reflectances and indices (4 km spacial resolution) every seven days for each 16 km map cell between 75EN and 55ES covering all land ecosystems. The data includes raw and calibrated radiances in the visible, near infrared and infrared spectral bands, processed (with eliminated high frequency noise) radiances, normalized difference vegetation index (NDVI), 20-year climatology, vegetation condition indices and also products, such as vegetation health, drought, vegetation fraction, fire risk etc. In the past ten years, users around the world used this information addressing different issues of drought impacts on socioeconomic activities and responded positively to real time drought information place regularly on the

  13. Galileo SSI Observations of Volcanic Activity at Tvashtar Catena, Io

    NASA Technical Reports Server (NTRS)

    Milazzo, M. P.; Keszthely, L. P.; Radebaugh, J.; Davies, A. G.; Turtle, E. P.; Geissler, P.; Klaasen, K. P.; McEwen, A. S.

    2005-01-01

    Introduction: We report on the analysis of the Galileo SSI's observations of the volcanic activity at Tvashtar Catena, Io as discussed by Milazzo et al. Galileo's Solid State Imager (SSI) observed Tvashtar Catena (63 deg N, 120 deg W) four times between November 1999 and October 2001, providing a unique look at the distinctive high latitude volcanism on Io. The November 1999 observation spatially resolved, for the first time, an active extraterrestrial fissure eruption. The brightness temperature of the lavas at the November 1999 fissure eruption was 1300 K. The second observation (orbit I27, February 2000) showed a large (approx. 500 sq km) region with many, small spots of hot, active lava. The third observation was taken in conjunction with a Cassini observation in December 2000 and showed a Pele-like plume deposition ring, while the Cassini images revealed a 400 km high Pele-type plume above the Catena. The final Galileo SSI observation of Tvashtar was acquired in October 2001, and all obvious (to SSI) activity had ceased, although data from Galileo's Near Infrared Mapping Spectrometer (NIMS) indicated that there was still significant thermal emission from the Tvashtar region. We have concentrated on analyzing the style of eruption during orbit I27 (February 2000). Comparison with a lava flow cooling model indicates that the behavior of the Tvashtar eruption during I27 does not match that of "simple" advancing lava flows. Instead, it may be an active lava lake or a complex set of lava flows with episodic, overlapping (in time and space) eruptions.

  14. Observed Helicity of Active Regions in Solar Cycle 21

    NASA Technical Reports Server (NTRS)

    Hagyard, M. J.; Pevtsov, A. A.; Blehm, Z.; Smith, J. E.; Six, Frank (Technical Monitor)

    2003-01-01

    We report the results of a study of helicity in solar active regions during the peak of activity in solar cycle 21 from observations with the Marshall Space Flight Center's solar vector magnetograph. Using the force-free parameter alpha as the proxy for helicity, we calculated an average value of alpha for each of 60 active regions from a total of 449 vector magnetograms that were obtained during the period 1980 March to November. The signs of these average values of alpha were correlated with the latitude of the active regions to test the hemispheric rule of helicity that has been proposed for solar magnetic fields: negative helicity predominant in northern latitudes, positive in the southern ones. We have found that of the 60 regions that were observed, 30 obey the hemispheric rule and 30 do not.

  15. Observed Divergence in the Attitudes of Incumbents and Supervisors as Subject Matter Experts in Job Analysis: A Study of the Fire Captain Rank.

    ERIC Educational Resources Information Center

    Mueller, Michael; Belcher, Greg

    2000-01-01

    A study compared attitudes of 20 incumbent fire captains and 11 supervisors about critical aspects of a fire captain's job. Results showed that they agree substantially about the criticality of tasks and moderately agree about Fire Captain attributes. (Contains 41 notes and references.) (JOW)

  16. A seizure-induced gain-of-function in BK channels is associated with elevated firing activity in neocortical pyramidal neurons

    PubMed Central

    Shruti, Sonal; Clem, Roger L.; Barth, Alison L.

    2009-01-01

    SUMMARY A heritable gain-of-function in BK channel activity has been associated with spontaneous seizures in both rodents and humans. We find that chemoconvulsant-induced seizures induce a gain-of-function in BK channel current that is associated with abnormal, elevated network excitability. Action potential half-width, evoked firing rate, and spontaneous network activity in vitro were all altered 24 hrs following picrotoxin-induced seizures in layer 2/3 pyramidal cells in the neocortex of young mice (P13-P16). Action potential half-width and firing output could be normalized to control values by application of BK channel antagonists in vitro. Thus, both inherited and acquired BK channel gain-of-functions are linked to abnormal excitability. Because BK channel antagonists can reduce elevated firing activity in neocortical neurons, BK channels might serve as a new target for anticonvulsant therapy. PMID:18387812

  17. Observation procedures characterizing occupational physical activities: critical review.

    PubMed

    Denis, D; Lortie, M; Rossignol, M

    2000-01-01

    The first objective of this paper is to compare the observation procedures proposed to characterize physical work. The second objective is to examine the following 3 methodological issues: reliability, observer training, and internal validity. Seventy-two papers were reviewed, 38 of which proposed a new or modified observation grid. The observation variables identified were broken down into 7 categories as follows: posture, exertion, load handled, work environment, use of feet, use of hands, and activities or tasks performed. The review revealed the variability of existing procedures. The examination of methodological issues showed that observation data can be reliable and can present an adequate internal validity. However, little information about the conditions necessary to achieve good reliability was available.

  18. Regional Observation of Seismic Activity in Baekdu Mountain

    NASA Astrophysics Data System (ADS)

    Kim, Geunyoung; Che, Il-Young; Shin, Jin-Soo; Chi, Heon-Cheol

    2015-04-01

    Seismic unrest in Baekdu Mountain area between North Korea and Northeast China region has called attention to geological research community in Northeast Asia due to her historical and cultural importance. Seismic bulletin shows level of seismic activity in the area is higher than that of Jilin Province of Northeast China. Local volcanic observation shows a symptom of magmatic unrest in period between 2002 and 2006. Regional seismic data have been used to analyze seismic activity of the area. The seismic activity could be differentiated from other seismic phenomena in the region by the analysis.

  19. Teaching Writing. Three Seasonal Activities to Hone Kids' Observation Skills.

    ERIC Educational Resources Information Center

    Power, Brenda

    1997-01-01

    The seasonal activities presented are: observing herbs to encourage use of the senses in writing; watching a jack-o'-lantern wither to learn skills in writing details; and building snowmen to learn to explain a string of events in writing. (SM)

  20. Burst-firing activity of presumed 5-HT neurones of the rat dorsal raphe nucleus: electrophysiological analysis by antidromic stimulation.

    PubMed

    Hajós, M; Sharp, T

    1996-11-18

    We recently reported raphe neurones which frequently fired spikes in short bursts. However, the action potentials were broad and the neurones fired in a slow and regular pattern, suggesting they were an unusual type of 5-hydroxytryptamine (5-HT) neurone. In the present study, we investigated whether these putative burst-firing 5-HT neurones project to the forebrain and whether all spikes fired in bursts propagate along the axon. In anaesthetised rats, electrical stimulation of the medial forebrain bundle evoked antidromic spikes in both burst-firing neurones and in single-spiking, classical 5-HT neurones recorded in the dorsal raphe nucleus. Although the antidromic spike latency of the single-spiking and burst-firing neurones showed a clear overlap, burst-firing neurones had a significantly shorter latency than single-spiking neurones. For both burst-firing neurones and classical 5-HT neurones, antidromic spikes made collisions with spontaneously occurring spikes. Furthermore, in all burst-firing neurones tested, first, second and third order spikes in a burst could be made to collide with antidromic spike. Interestingly, in a small number of burst-firing neurones, antidromic stimulation evoked spike doublets, similar to those recorded spontaneously. From these data we conclude that burst-firing neurones in the dorsal raphe nucleus project to the forebrain, and each spike generated by the burst propagates along the axon and could thereby release transmitter (5-HT).

  1. First OSIRIS observations of active areas on comet 67P

    NASA Astrophysics Data System (ADS)

    Vincent, J.-B.; Sierks, H.; Oklay, N.; Agarwal, J.; Güttler, C.; Bodewits, D.; Osiris Team

    2014-04-01

    After a successful exit from hibernation, Rosetta started observing its final target comet 67P in March 2014 with the two OSIRIS cameras WAC and NAC (Wide Angle and Narrow Angle Camera) [1]. By the time of this conference, the spacecraft will have flown from 5 million to 50 km from the nucleus surface, reaching a resolution of 1 meter/pixel in the NAC images. During that period, the comet heliocentric distance varies from 4.3 to 3.2 AU and we will observe how the early activity develops. We know that cometary surfaces are not fully active; only a small fraction of the surface emits gas and dust. However we do not yet understand why it happens in that way, and what to expect on 67P. Recent publications using data from ground-based telescopes have proposed different interpretations for the distribution of active sources, from one to three at various latitudes [2, 3]. There is some evidence for different levels of activity in the northern and southern hemispheres, but these variations can only be constrained with close range data. In August 2014, OSIRIS will map the surface of the comet at high resolution, and perform weekly monitoring of the activity, especially the faintest jets. With these images and the inversion code COSSIM [4], we will be able to link observed features in the coma or on the limb to physical spots on the surface. On other comets visited by spacecrafts the activity has sometimes been associated with smooth areas, rough terrains, or specific morphologic features (cliff, crater, rim, . . . ). We will present a first look at how activity and terrain are linked on 67P, and look at variations of composition, morphology, or both. We will compare this identification of active areas to previous publications.

  2. Observational evidence for enhanced magnetic activity of superflare stars.

    PubMed

    Karoff, Christoffer; Knudsen, Mads Faurschou; De Cat, Peter; Bonanno, Alfio; Fogtmann-Schulz, Alexandra; Fu, Jianning; Frasca, Antonio; Inceoglu, Fadil; Olsen, Jesper; Zhang, Yong; Hou, Yonghui; Wang, Yuefei; Shi, Jianrong; Zhang, Wei

    2016-03-24

    Superflares are large explosive events on stellar surfaces one to six orders-of-magnitude larger than the largest flares observed on the Sun throughout the space age. Due to the huge amount of energy released in these superflares, it has been speculated if the underlying mechanism is the same as for solar flares, which are caused by magnetic reconnection in the solar corona. Here, we analyse observations made with the LAMOST telescope of 5,648 solar-like stars, including 48 superflare stars. These observations show that superflare stars are generally characterized by larger chromospheric emissions than other stars, including the Sun. However, superflare stars with activity levels lower than, or comparable to, the Sun do exist, suggesting that solar flares and superflares most likely share the same origin. The very large ensemble of solar-like stars included in this study enables detailed and robust estimates of the relation between chromospheric activity and the occurrence of superflares.

  3. Observational evidence for enhanced magnetic activity of superflare stars

    PubMed Central

    Karoff, Christoffer; Knudsen, Mads Faurschou; De Cat, Peter; Bonanno, Alfio; Fogtmann-Schulz, Alexandra; Fu, Jianning; Frasca, Antonio; Inceoglu, Fadil; Olsen, Jesper; Zhang, Yong; Hou, Yonghui; Wang, Yuefei; Shi, Jianrong; Zhang, Wei

    2016-01-01

    Superflares are large explosive events on stellar surfaces one to six orders-of-magnitude larger than the largest flares observed on the Sun throughout the space age. Due to the huge amount of energy released in these superflares, it has been speculated if the underlying mechanism is the same as for solar flares, which are caused by magnetic reconnection in the solar corona. Here, we analyse observations made with the LAMOST telescope of 5,648 solar-like stars, including 48 superflare stars. These observations show that superflare stars are generally characterized by larger chromospheric emissions than other stars, including the Sun. However, superflare stars with activity levels lower than, or comparable to, the Sun do exist, suggesting that solar flares and superflares most likely share the same origin. The very large ensemble of solar-like stars included in this study enables detailed and robust estimates of the relation between chromospheric activity and the occurrence of superflares. PMID:27009381

  4. Comparison of the genotoxic activities of extracts from ambient and forest fire polluted air. [Humans

    SciTech Connect

    Viau, C.J.; Lockard, J.M.; Enoch, H.G.; Sabharwal, P.S.

    1982-01-01

    The genotoxicity of airborne organic particles from forest fire smoke was compared to that from nonsmoky (ambient) urban air using the Salmonella reversion assay and the sister chromatid exchange (SCE) assay in cultured human lymphocytes. Salmonella strains TA98 and TA100 were used with and without the addition of Aroclor-induced rat liver homogenate (S9). Each sample induced dose-related increases in mutagenicity and SCE. However, on the basis of the volume of air sampled, the smoke-filled air induced 12 to 14 times more bacterial reversions in TA 100 and 16-38 times more reversion in TA98 than ambient air. Similarly, on a volume basis smoky air induced 43 times more SCE in human lymphocytes than did ambient air. The results indicate that the increased mutagenicity was due not only to the heavier particulate load of the air, but also to the increased specific mutagenicity of the particles.

  5. Spatiotemporal patterns of tundra fires: late-Quaternary charcoal records from Alaska

    NASA Astrophysics Data System (ADS)

    Chipman, M. L.; Hudspith, V.; Higuera, P. E.; Duffy, P. A.; Kelly, R.; Oswald, W. W.; Hu, F. S.

    2015-07-01

    Anthropogenic climate change has altered many ecosystem processes in the Arctic tundra and may have resulted in unprecedented fire activity. Evaluating the significance of recent fires requires knowledge from the paleofire record because observational data in the Arctic span only several decades, much shorter than the natural fire rotation in Arctic tundra regions. Here we report results of charcoal analysis on lake sediments from four Alaskan lakes to infer the broad spatial and temporal patterns of tundra-fire occurrence over the past 35 000 years. Background charcoal accumulation rates are low in all records (range is 0-0.05 pieces cm-2 yr-1), suggesting minimal biomass burning across our study areas. Charcoal peak analysis reveals that the mean fire-return interval (FRI; years between consecutive fire events) ranged from ca. 1650 to 6050 years at our sites, and that the most recent fire events occurred from ca. 880 to 7030 years ago, except for the CE 2007 Anaktuvuk River Fire. These mean FRI estimates are longer than the fire rotation periods estimated for the past 63 years in the areas surrounding three of the four study lakes. This result suggests that the frequency of tundra burning was higher over the recent past compared to the late Quaternary in some tundra regions. However, the ranges of FRI estimates from our paleofire records overlap with the expected values based on fire-rotation-period estimates from the observational fire data, and the differences are statistically insignificant. Together with previous tundra-fire reconstructions, these data suggest that the rate of tundra burning was spatially variable and that fires were extremely rare in our study areas throughout the late Quaternary. Given the rarity of tundra burning over multiple millennia in our study areas and the pronounced effects of fire on tundra ecosystem processes such as carbon cycling, dramatic tundra ecosystem changes are expected if anthropogenic climate change leads to more

  6. Fire in Fennoscandia: A palaeo-perspective of spatial and temporal variability in fire frequency and vegetation dynamics

    NASA Astrophysics Data System (ADS)

    Clear, Jennifer; Bradshaw, Richard; Seppä, Heikki

    2014-05-01

    Active fire suppression in Fennoscandia has created a boreal forest ecosystem that is almost free of fire. Absence of fire is thought to have contributed to the widespread dominance of Picea abies (Norway spruce), though the character and structure of spruce forests operates as a positive feedback retarding fire frequency. This lack of fire and dominance by Picea abies may have assisted declines in deciduous tree species, with a concomitant loss of floristic diversity. Forest fires are driven by a complex interplay between natural (climate, vegetation and topography) and anthropogenic disturbance and through palaeoecology we are able to explore spatio-temporal variability in the drivers of fire, changing fire dynamics and the subsequent consequences for forest succession, development and floristic diversity over long timescales. High resolution analysis of palaeoenvironmental proxies (pollen and macroscopic charcoal) allows Holocene vegetation and fire dynamics to be reconstructed at the local forest-stand scale. Comparisons of fire histories with pollen-derived quantitative reconstruction of vegetation at local- and regional-scales identify large-scale ecosystem responses and local-scale disturbance. Spatio-temporal heterogeneity and variability in biomass burning is explored to identify the drivers of fire and palaeovegetation reconstructions are compared to process-based, climate-driven dynamic vegetation model output to test the significance of fire frequency as a driver of vegetation composition and dynamics. Fire was not always so infrequent in the northern European forest with early-Holocene fire regimes driven by natural climate variations and fuel availability. The establishment and spread of Picea abies was probably driven by an increase in continentality of climate, but local natural and anthropogenic ecosystem disturbance may have aided this spread. Picea expansion led to a step-wise reduction in regional biomass burning and here we show the now

  7. Small conductance Ca2+-activated K+ channels regulate firing properties and excitability in parasympathetic cardiac motoneurons in the nucleus ambiguus.

    PubMed

    Lin, Min; Hatcher, Jeff T; Chen, Qin-Hui; Wurster, Robert D; Cheng, Zixi Jack

    2010-12-01

    Small conductance Ca(2+)-activated K(+) channels (SK) regulate action potential (AP) firing properties and excitability in many central neurons. However, the functional roles of SK channels of parasympathetic cardiac motoneurons (PCMNs) in the nucleus ambiguus have not yet been well characterized. In this study, the tracer X-rhodamine-5 (and 6)-isothiocyanate (XRITC) was injected into the pericardial sac to retrogradely label PCMNs in FVB mice at postnatal days 7-9. Two days later, XRITC-labeled PCMNs in brain stem slices were identified. With the use of whole cell current clamp, single APs and spike trains of different frequencies were evoked by current injections. We found that 1) PCMNs have two different firing patterns: the majority of PCMNs (90%) exhibited spike frequency adaptation (SFA) and the rest (10%) showed less or no adaptation; 2) application of the specific SK channel blocker apamin significantly increased spike half-width in single APs and trains and reduced the spike frequency-dependent AP broadening in trains; 3) SK channel blockade suppressed afterhyperpolarization (AHP) amplitude following single APs and trains and abolished spike-frequency dependence of AHP in trains; and 4) SK channel blockade increased the spike frequency but did not alter the pattern of SFA. Using whole cell voltage clamp, we measured outward currents and afterhyperpolarization current (I(AHP)). SK channel blockade revealed that SK-mediated outward currents had both transient and persistent components. After bath application of apamin and Ca(2+)-free solution, we found that apamin-sensitive and Ca(2+)-sensitive I(AHP) were comparable, confirming that SK channels may contribute to a major portion of Ca(2+)-activated K(+) channel-mediated I(AHP). These results suggest that PCMNs have SK channels that significantly regulate AP repolarization, AHP, and spike frequency but do not affect SFA. We conclude that activation of SK channels underlies one of the mechanisms for negative

  8. NIMS Observes Increased Activity at Loki Patera, Io

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Loki Patera, historically the most active and persistent hot spot on Io, is located on the hemisphere of Io always facing Jupiter. Loki Patera was the site of two plumes during the Voyager encounters, which were not seen during the early orbits of Galileo. Ground-based observers reported Loki Patera to be unusually dim during this time, marking a period of low volcanic activity.

    On 21 February 1997, during Galileo's sixth orbit, the Near Infrared Mapping Spectrometer (NIMS) on the Galileo spacecraft observed Io in daylight from a range of approximately 703,000 km (440,000 miles). The image on the left shows Io at a wavelength of 2.95 microns. Loki Patera is seen to be relatively quiescent (at longer wavelengths which are more sensitive to thermal emission, Loki Patera is more noticeable).

    A few weeks later, on March 12th 1997, ground based observers using the Infra-Red Telescope Facility (IRTF) on Mauna Kea, Hawaii, observed an intense brightening in the Loki region, so much that Loki was contributing 75% of Io's in-eclipse flux for this hemisphere. A large eruption was taking place! Other ground-based observations through March, April and May tracked the course of the activity and confirmed its location at Loki Patera.

    On 4 April 1997, NIMS again observed Io during the seventh orbit from a range of 556,000 km (348,000 miles), with Loki Patera positioned in darkness, close to the limb. The image on the right shows the increase in activity at Loki Patera, again at 2.95 microns. A preliminary single temperature fit to NIMS orbit seven Loki Patera hot spot data yields a temperature of 500 K and an area of over 800 square kilometers. That the image is so bright at this wavelength is an indication of the areal extent of the activity. It is also probable that some part of the volcanic material being erupted or exposed is at considerably higher temperatures than that of the 500 K single-temperature fit.

    Io is under observation by ground-based observers under

  9. Fires in Myanmar (2007)

    NASA Technical Reports Server (NTRS)

    2007-01-01

    In Southeast Asia, fires are common and widespread throughout the dry season, which roughly spans the northern hemisphere winter months. People set fires to clear crop stubble and brush and to prepare grazing land for a new flush of growth when the rainy season arrives. These intentional fires are too frequently accompanied by accidental fires that invade nearby forests and woodlands. The combination of fires produces a thick haze that alternately lingers and disperses, depending on the weather. This image from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite shows fire activity on March 19, 2007, across eastern India, Myanmar, Thailand, Laos, and China. Places where MODIS detected actively burning fires are marked in red on the image. The darker green areas are generally more wooded areas or forests, while the paler green and tan areas are agricultural land. Smoke pools over low-lying areas of the hilly terrain in gray pockets. The green tops of rolling hills in Thailand emerge from a cloud of low-lying smoke. According to news reports from Thailand, the smoke blanket created air quality conditions that were considered unhealthy for all groups, and it prompted the Thai Air Force to undertake cloud-seeding attempts in an effort to cleanse the skies with rain. Commercial air traffic was halted due to poor visibility.

  10. CROSS-DISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY: Small-World Connections to Induce Firing Activity and Phase Synchronization in Neural Networks

    NASA Astrophysics Data System (ADS)

    Qin, Ying-Hua; Luo, Xiao-Shu

    2009-07-01

    We investigate how the firing activity and the subsequent phase synchronization of neural networks with small-world topological connections depend on the probability p of adding-links. Network elements are described by two-dimensional map neurons (2DMNs) in a quiescent original state. Neurons burst for a given coupling strength when the topological randomness p increases, which is absent in a regular-lattice neural network. The bursting activity becomes frequent and synchronization of neurons emerges as topological randomness further increases. The maximal firing frequency and phase synchronization appear at a particular value of p. However, if the randomness p further increases, the firing frequency decreases and synchronization is apparently destroyed.

  11. MU radar observation of the strong activity of 2006 Quadrantids

    NASA Astrophysics Data System (ADS)

    Abe, S.; Nakamura, T.; Watanabe, J.-I.; Tsutsumi, M.; Fujiwara, Y.; Ueda, M.; Yamamoto, M.-Y.; Mukai, T.

    Prominent activity of the 2006 Quadrantid meteor shower was observed from 18h through 21h UT on January 3 in Japan We carried out using a MU radar located in Shigaraki Japan which is a Mesosphere Stratosphere and Troposphere radar with a frequency and a peak power of 46 5 MHz and 1MW respectively The radar is consists of 475 Yagi antenna elements and the observation was performed in the meteor observation mode In order to calculate the ideal echo rate a response function which is the response of the radar system to a radiant in any position on the sky was considered Background activities were subtracted to estimate the Quadrantids activity with sufficient accuracy Velocity and echo height distribution were also derived Finally meteor radiant distribution RA 231 deg DEC 51 deg was calculated by using several thousands of echoes during Quadrantids activity A new system was installed to enhance the performance of the radar It consists of an Ultra Multi-channel Digital Receiving Subsystem and a Low-loss Signal Transfer Subsystem We will present the details of the 2006 Quadrantids characteristics by means of the new analysis method and the new system

  12. Future Integrated Fire Control

    DTIC Science & Technology

    2005-06-01

    this illustration, the remote unit provides fire control quality ( FCQ ) data of the threat to the firing unit throughout the engagement. The firing...interceptor; tasking sensors & communication resources; ensuring resources are committed; monitoring resource performance; ensuring FCQ data is...FC LoR EoR FP RF PSD Object Observ. R R R L or R R L or R Object Trking/ID L & R R R L or R R L or R FCQ Data Attain. L R& L R L or R

  13. Action observation activates neurons of the monkey ventrolateral prefrontal cortex

    PubMed Central

    Simone, Luciano; Bimbi, Marco; Rodà, Francesca; Fogassi, Leonardo; Rozzi, Stefano

    2017-01-01

    Prefrontal cortex is crucial for exploiting contextual information for the planning and guidance of behavioral responses. Among contextual cues, those provided by others’ behavior are particularly important, in primates, for selecting appropriate reactions and suppressing the inappropriate ones. These latter functions deeply rely on the ability to understand others’ actions. However, it is largely unknown whether prefrontal neurons are activated by action observation. To address this issue, we recorded the activity of ventrolateral prefrontal (VLPF) neurons of macaque monkeys during the observation of videos depicting biological movements performed by a monkey or a human agent, and object motion. Our results show that a population of VLPF neurons respond to the observation of biological movements, in particular those representing goal directed actions. Many of these neurons also show a preference for the agent performing the action. The neural response is present also when part of the observed movement is obscured, suggesting that these VLPF neurons code a high order representation of the observed action rather than a simple visual description of it. PMID:28290511

  14. Modeling the Optical Properties of Biomass Burning Aerosols: Young Smoke Aerosols From Savanna Fires and Comparisons to Observations from SAFARI 2000

    NASA Technical Reports Server (NTRS)

    Matichuk, R. I.; Smith, J. A.; Toon, O. B.; Colarso, P. R.

    2006-01-01

    Annually, farmers in southern Africa manage their land resources and prepare their fields for cultivation by burning crop residual debris, with a peak in the burning season occurring during August and September. The emissions from these fires in southern Africa are among the greatest from fires worldwide, and the gases and aerosol particles produced adversely affect air quality large distances from their source regions, and can even be tracked in satellite imagery as they cross the Atlantic and Pacific Ocean basins. During August and September 2000 an international group of researchers participating in the Southern African Regional Science Initiate field experiment (SAFARI 2000) made extensive ground-based, airborne, and satellite measurements of these gases and aerosols in order to quantify their amounts and effects on Earth's atmosphere. In this study we interpreted the measurements of smoke aerosol particles made during SAFARI 2000 in order to better represent these particles in a numerical model simulating their transport and fate. Typically, smoke aerosols emitted from fires are concentrated by mass in particles about 0.3 micrometers in diameter (1,000,000 micrometers = 1 meter, about 3 feet); for comparison, the thickness of a human hair is about 50 micrometers, almost 200 times as great. Because of the size of these particles, at the surface they can be easily inhaled into the lungs, and in high concentrations have deleterious health effects on humans. Additionally, these particles reflect and absorb sunlight, impacting both visibility and the balance of sunlight reaching -Earth's surface, and ultimately play a role in modulating Earth's climate. Because of these important effects, it is important that numerical models used to estimate Earth's climate response to changes in atmospheric composition accurately represent the quantity and evolution of smoke particles. In our model, called the Community Aerosol and Radiation Model for Atmospheres (CARMA) we used

  15. OBSERVABILITY OF DUAL ACTIVE GALACTIC NUCLEI IN MERGING GALAXIES

    SciTech Connect

    Van Wassenhove, Sandor; Volonteri, Marta; Bellovary, Jillian; Mayer, Lucio; Callegari, Simone; Dotti, Massimo

    2012-03-20

    Supermassive black holes (SMBHs) have been detected in the centers of most nearby massive galaxies. Galaxies today are not only the products of billions of years of galaxy mergers, but also billions of years of SMBH activity as active galactic nuclei (AGNs) that is connected to galaxy mergers. In this context, detection of AGN pairs should be relatively common. Observationally, however, dual AGNs are scant, being just a few percent of all AGNs. In this Letter, we investigate the triggering of AGN activity in merging galaxies via a suite of high-resolution hydrodynamical simulations. We follow the dynamics and accretion onto the SMBHs as they move from separations of tens of kiloparsecs to tens of parsecs. Our resolution, cooling, and star formation implementation produce an inhomogeneous, multi-phase interstellar medium, allowing us to accurately trace star formation and accretion onto the SMBHs. We study the impact of gas content, morphology, and mass ratio, focusing on AGN activity and dynamics across a wide range of relevant conditions. We test when the two AGNs are simultaneously detectable, for how long and at which separations. We find that strong dual AGN activity occurs during the late phases of the mergers, at small separations (<1-10 kpc) below the resolution limit of most surveys. Much of the SMBH accretion is not simultaneous, limiting the dual AGN fraction detectable through imaging and spectroscopy to a few percent, in agreement with observational samples.

  16. Underwater observations of active lava flows from Kilauea volcano, Hawaii

    USGS Publications Warehouse

    Tribble, G.W.

    1991-01-01

    Underwater observation of active submarine lava flows from Kilauea volcano, Hawaii, in March-June 1989 revealed both pillow lava and highly channelized lava streams flowing down a steep and unconsolidated lava delta. The channelized streams were 0.7-1.5 m across and moved at rates of 1-3 m/s. The estimated flux of a stream was 0.7 m3/s. Jets of hydrothermal water and gas bubbles were associated with the volcanic activity. The rapidly moving channelized lava streams represent a previously undescribed aspect of submarine volcanism. -Author

  17. Chemical Bond Activation Observed with an X-ray Laser.

    PubMed

    Beye, Martin; Öberg, Henrik; Xin, Hongliang; Dakovski, Georgi L; Dell'Angela, Martina; Föhlisch, Alexander; Gladh, Jörgen; Hantschmann, Markus; Hieke, Florian; Kaya, Sarp; Kühn, Danilo; LaRue, Jerry; Mercurio, Giuseppe; Minitti, Michael P; Mitra, Ankush; Moeller, Stefan P; Ng, May Ling; Nilsson, Anders; Nordlund, Dennis; Nørskov, Jens; Öström, Henrik; Ogasawara, Hirohito; Persson, Mats; Schlotter, William F; Sellberg, Jonas A; Wolf, Martin; Abild-Pedersen, Frank; Pettersson, Lars G M; Wurth, Wilfried

    2016-09-15

    The concept of bonding and antibonding orbitals is fundamental in chemistry. The population of those orbitals and the energetic difference between the two reflect the strength of the bonding interaction. Weakening the bond is expected to reduce this energetic splitting, but the transient character of bond-activation has so far prohibited direct experimental access. Here we apply time-resolved soft X-ray spectroscopy at a free-electron laser to directly observe the decreased bonding-antibonding splitting following bond-activation using an ultrashort optical laser pulse.

  18. Brain activity modeling in general anesthesia: Enhancing local mean-field models using a slow adaptive firing rate

    NASA Astrophysics Data System (ADS)

    Molaee-Ardekani, B.; Senhadji, L.; Shamsollahi, M. B.; Vosoughi-Vahdat, B.; Wodey, E.

    2007-10-01

    In this paper, an enhanced local mean-field model that is suitable for simulating the electroencephalogram (EEG) in different depths of anesthesia is presented. The main building elements of the model (e.g., excitatory and inhibitory populations) are taken from Steyn-Ross [M. L. Steyn-Ross , Phys. Rev. E 64, 011917 (2001), D. A. Steyn-Ross , Phys. Rev. E 64, 011918 (2001)] and Bojak and Liley [I. Bojak and D. T. Liley, Phys. Rev. E 71, 041902 (2005)] mean-field models and a new slow ionic mechanism is included in the main model. Generally, in mean-field models, some sigmoid-shape functions determine firing rates of neural populations according to their mean membrane potentials. In the enhanced model, the sigmoid function corresponding to excitatory population is redefined to be also a function of the slow ionic mechanism. This modification adapts the firing rate of neural populations to slow ionic activities of the brain. When an anesthetic drug is administered, the slow mechanism may induce neural cells to alternate between two levels of activity referred to as up and down states. Basically, the frequency of up-down switching is in the delta band (0-4Hz) and this is the main reason behind high amplitude, low frequency fluctuations of EEG signals in anesthesia. Our analyses show that the enhanced model may have different working states driven by anesthetic drug concentration. The model is settled in the up state in the waking period, it may switch to up and down states in moderate anesthesia while in deep anesthesia it remains in the down state.

  19. Daily and 3-hourly Variability in Global Fire Emissions and Consequences for Atmospheric Model Predictions of Carbon Monoxide

    NASA Technical Reports Server (NTRS)

    Mu, M.; Randerson, J. T.; vanderWerf, G. R.; Giglio, L.; Kasibhatla, P.; Morton, D.; Collatz, G. J.; DeFries, R. S.; Hyer, E. J.; Prins, E. M.; Griffith, D. W. T.; Wunch, D.; Toon, G. C.; Sherlock, V.; Wennberg, P. O.

    2011-01-01

    Attribution of the causes of atmospheric trace gas and aerosol variability often requires the use of high resolution time series of anthropogenic and natural emissions inventories. Here we developed an approach for representing synoptic- and diurnal-scale temporal variability in fire emissions for the Global Fire Emissions Database version 3 (GFED3). We disaggregated monthly GFED3 emissions during 2003.2009 to a daily time step using Moderate Resolution Imaging Spectroradiometer (MODIS) ]derived measurements of active fires from Terra and Aqua satellites. In parallel, mean diurnal cycles were constructed from Geostationary Operational Environmental Satellite (GOES) Wildfire Automated Biomass Burning Algorithm (WF_ABBA) active fire observations. Daily variability in fires varied considerably across different biomes, with short but intense periods of daily emissions in boreal ecosystems and lower intensity (but more continuous) periods of burning in savannas. These patterns were consistent with earlier field and modeling work characterizing fire behavior dynamics in different ecosystems. On diurnal timescales, our analysis of the GOES WF_ABBA active fires indicated that fires in savannas, grasslands, and croplands occurred earlier in the day as compared to fires in nearby forests. Comparison with Total Carbon Column Observing Network (TCCON) and Measurements of Pollution in the Troposphere (MOPITT) column CO observations provided evidence that including daily variability in emissions moderately improved atmospheric model simulations, particularly during the fire season and near regions with high levels of biomass burning. The high temporal resolution estimates of fire emissions developed here may ultimately reduce uncertainties related to fire contributions to atmospheric trace gases and aerosols. Important future directions include reconciling top ]down and bottom up estimates of fire radiative power and integrating burned area and active fire time series from

  20. Hayman Fire, Colorado

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The Hayman forest fire, started on June 8, is continuing to burn in the Pike National Forest, 57 km (35 miles) south-southwest of Denver. According to the U.S. Forest Service, the fire has consumed more than 90,000 acres and has become Colorado's worst fire ever. In this ASTER image, acquired Sunday, June 16, 2002 at 10:30 am MST, the dark blue area is burned vegetation and the green areas are healthy vegetation. Red areas are active fires, and the blue cloud at the top center is smoke. Meteorological clouds are white. The image covers an area of 32.2 x 35.2 km (20.0 x 21.8 miles), and displays ASTER bands 8-3-2 in red, green and blue.

    This image was acquired on June 16, 2002 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER will image Earth for the next 6 years to map and monitor the changing surface of our planet.

    ASTER is one of five Earth-observing instruments launched December 18,1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, California, is the U.S. Science team leader; Bjorn Eng of JPL is the project manager. The Terra mission is part of NASA's Earth Science Enterprise, a long-term research and technology program designed to examine Earth's land, oceans, atmosphere, ice and life as a total integrated system.

    The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping, and monitoring dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats

  1. Witch Wildland Fire, California

    NASA Technical Reports Server (NTRS)

    2007-01-01

    The October wildfires that plagued southern California were some of the worst on record. One of these, the Witch Wildland fire, burned 198,000 acres north of San Diego, destroying 1125 homes, commercial structures, and outbuildings. Over 3,000 firefighters finally contained the fire two weeks after it started on October 21. Now begins the huge task of planning and implementing mitigation measures to replant and reseed the burned areas. This ASTER image depicts the area after the fire, on November 6; vegetation is green, burned areas are dark red, and urban areas are blue. On the burn severity index image, calculated using infrared and visible bands, red areas are the most severely burned, followed by green and blue. This information can help the US Forest Service to plan post-fire activities.

    With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER images Earth to map and monitor the changing surface of our planet.

    ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra spacecraft. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products.

    The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping, and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory

  2. Fire and smoke retardants

    NASA Astrophysics Data System (ADS)

    Drews, M. J.

    Despite a reduction in Federal regulatory activity, research concerned with flame retardancy and smoke suppression in the private sector appears to be increasing. This trend seem related to the increased utilization of plastics for end uses which traditionally have employed metal or wood products. As a result, new markets have appeared for thermally stable and fire resistance thermoplastic materials, and this in turn has spurred research and development activity. In addition, public awareness of the dangers associated with fire has increased as a result of several highly publicized hotel and restaurant fires within the past two years. The consumers recognition of flammability characteristics as important materials property considerations has increased. The current status of fire and smoke retardant chemistry and research are summarized.

  3. Fire clay

    USGS Publications Warehouse

    Virta, R.L.

    2011-01-01

    The article discusses the latest developments in the fire clay industry, particularly in the U.S., as of June 2011. It claims that the leading fire clay producer in the U.S. is the state of Missouri. The other major producers include California, Texas and Washington. It reports that the use of heavy clay products made of fire clay like brick, cement and lightweight aggregate has increased slightly in 2010.

  4. Fire clay

    USGS Publications Warehouse

    Virta, R.L.

    2006-01-01

    In 2005, six companies mined fire clay in Missouri, Ohio and South Carolina. Production was estimate to be 300 kt with a value of $8.3 million. Missouri was the leading producer state followed by Ohio and South Carolina. For the third consecutive year, sales and use of fire clays have been relatively unchanged. For the next few years, sales of fire clay is forecasted to remain around 300 kt/a.

  5. Firing behavior of vestibular neurons during active and passive head movements: vestibulo-spinal and other non-eye-movement related neurons

    NASA Technical Reports Server (NTRS)

    McCrea, R. A.; Gdowski, G. T.; Boyle, R.; Belton, T.; Peterson, B. W. (Principal Investigator)

    1999-01-01

    The firing behavior of 51 non-eye movement related central vestibular neurons that were sensitive to passive head rotation in the plane of the horizontal semicircular canal was studied in three squirrel monkeys whose heads were free to move in the horizontal plane. Unit sensitivity to active head movements during spontaneous gaze saccades was compared with sensitivity to passive head rotation. Most units (29/35 tested) were activated at monosynaptic latencies following electrical stimulation of the ipsilateral vestibular nerve. Nine were vestibulo-spinal units that were antidromically activated following electrical stimulation of the ventromedial funiculi of the spinal cord at C1. All of the units were less sensitive to active head movements than to passive whole body rotation. In the majority of cells (37/51, 73%), including all nine identified vestibulo-spinal units, the vestibular signals related to active head movements were canceled. The remaining units (n = 14, 27%) were sensitive to active head movements, but their responses were attenuated by 20-75%. Most units were nearly as sensitive to passive head-on-trunk rotation as they were to whole body rotation; this suggests that vestibular signals related to active head movements were cancelled primarily by subtraction of a head movement efference copy signal. The sensitivity of most units to passive whole body rotation was unchanged during gaze saccades. A fundamental feature of sensory processing is the ability to distinguish between self-generated and externally induced sensory events. Our observations suggest that the distinction is made at an early stage of processing in the vestibular system.

  6. Fire clay

    USGS Publications Warehouse

    Virta, R.L.

    2013-01-01

    Four companies mined fire clay in three states in 2012. Production, based on a preliminary survey of the fire clay industry, was estimated to be 230 kt (254,000 st) valued at $6.98 million, an increase from 215 kt (237,000 st) valued at $6.15 million in 2011. Missouri was the leading producing state, followed by Colorado and Texas, in decreasing order by quantity. The number of companies mining fire clay declined in 2012 because several common clay producers that occasionally mine fire clay indicated that they did not do so in 2012.

  7. Active Region Moss: Doppler Shifts from Hinode/EIS Observations

    NASA Technical Reports Server (NTRS)

    Tripathi, Durgesh; Mason, Helen E.; Klimchuk, James A.

    2012-01-01

    Studying the Doppler shifts and the temperature dependence of Doppler shifts in moss regions can help us understand the heating processes in the core of the active regions. In this paper we have used an active region observation recorded by the Extreme-ultraviolet Imaging Spectrometer (EIS) onboard Hinode on 12-Dec- 2007 to measure the Doppler shifts in the moss regions. We have distinguished the moss regions from the rest of the active region by defining a low density cut-off as derived by Tripathi et al. (2010). We have carried out a very careful analysis of the EIS wavelength calibration based on the method described in Young, O Dwyer and Mason (2012). For spectral lines having maximum sensitivity between log T = 5.85 and log T = 6.25 K, we find that the velocity distribution peaks at around 0 km/s with an estimated error of 4 km/s. The width of the distribution decreases with temperature. The mean of the distribution shows a blue shift which increases with increasing temperature and the distribution also shows asymmetries towards blue-shift. Comparing these results with observables predicted from different coronal heating models, we find that these results are consistent with both steady and impulsive heating scenarios. Further observational constraints are needed to distinguish between these two heating scenarios.

  8. Photometric observations of the energetics of small solar active regions

    SciTech Connect

    Lawrence, J.K.; Chapman, G.A. )

    1990-10-01

    The energetics of small solar active regions was investigated using for the analysis the photometric solar images taken from July 29 to September 6, 1984 with the San Fernando Observatory's 28-cm vacuum telescope, vacuum spectroheliograph, and dual 512 element Reticon linear diode arrays. Ten small newly formed regions were observed, whose entire sunspot evolution apparently occurred within the observed disk crossing. Seven of these showed a net energy excess of a few times 10 to the 33th ergs during this time. These results are discussed in connection with the 0.1 percent decline in solar irradiance observed by the SMM/ACRIM and Nimbus 7/ERB radiometers between 1980 and 1986. 35 refs.

  9. Social observation enhances cross-environment activation of hippocampal place cell patterns

    PubMed Central

    Mou, Xiang; Ji, Daoyun

    2016-01-01

    Humans and animals frequently learn through observing or interacting with others. The local enhancement theory proposes that presence of social subjects in an environment facilitates other subjects' understanding of the environment. To explore the neural basis of this theory, we examined hippocampal place cells, which represent spatial information, in rats as they stayed in a small box while a demonstrator rat running on a separate, nearby linear track, and as they ran on the same track themselves. We found that place cell firing sequences during self-running on the track also appeared in the box. This cross-environment activation occurred even prior to any self-running experience on the track and was absent without a demonstrator. Our data thus suggest that social observation can facilitate the observer’s spatial representation of an environment without actual self-exploration. This finding may contribute to neural mechanisms of local enhancement. DOI: http://dx.doi.org/10.7554/eLife.18022.001 PMID:27692067

  10. Continuous gravity observations at active volcanoes through superconducting gravimeters

    NASA Astrophysics Data System (ADS)

    Carbone, Daniele; Greco, Filippo

    2016-04-01

    Continuous gravity measurements at active volcanoes are usually taken through spring gravimeters that are easily portable and do not require much power to work. However, intrinsic limitations dictate that, when used in continuous, these instruments do not provide high-quality data over periods longer than some days. Superconducting gravimeters (SG), that feature a superconducting sphere in a magnetic field as the proof mass, provide better-quality data than spring gravimeters, but are bigger and need mains electricity to work, implying that they cannot be installed close to the active structures of high volcanoes. An iGrav SG was installed on Mt. Etna (Italy) in September 2014 and has worked almost continuously since then. It was installed about 6km from the active craters in the summit zone of the volcano. Such distance is normally too much to observe gravity changes due to relatively fast (minutes to days) volcanic processes. Indeed, mass redistributions in the shallowest part of the plumbing system induce short-wavelength gravity anomalies, centered below the summit craters. Nevertheless, thanks to the high precision and long-term stability of SGs, it was possible to observe low-amplitude changes over a wide range of timescales (minutes to months), likely driven by volcanic activity. Plans are in place for the implementation of a mini-array of SGs at Etna.

  11. The impact of chromospheric activity on observed initial mass functions

    SciTech Connect

    Stassun, Keivan G.; Scholz, Aleks; Dupuy, Trent J.; Kratter, Kaitlin M.

    2014-12-01

    Using recently established empirical calibrations for the impact of chromospheric activity on the radii, effective temperatures, and estimated masses of active low-mass stars and brown dwarfs, we reassess the shape of the initial mass function (IMF) across the stellar/substellar boundary in the Upper Sco star-forming region (age ∼ 5-10 Myr). We adjust the observed effective temperatures to warmer values using the observed strength of the chromospheric Hα emission, and redetermine the estimated masses of objects using pre-main-sequence evolutionary tracks in the H-R diagram. The effect of the activity-adjusted temperatures is to shift the objects to higher masses by 3%-100%. While the slope of the resulting IMF at substellar masses is not strongly changed, the peak of the IMF does shift from ≈0.06 to ≈0.11 M {sub ☉}. Moreover, for objects with masses ≲ 0.2 M {sub ☉}, the ratio of brown dwarfs to stars changes from ∼80% to ∼33%. These results suggest that activity corrections are essential for studies of the substellar mass function, if the masses are estimated from spectral types or from effective temperatures.

  12. The action of prostaglandin E2 and triamcinolone acetonide on the firing activity of lumbar nerve roots.

    PubMed

    Muramoto, T; Atsuta, Y; Iwahara, T; Sato, M; Takemitsu, Y

    1997-01-01

    Sciatica, due to lumbar disc herniation, is understood electrophysiogically to be an ectopic firing originating from a nerve root. The recent concept of chemical radiculitis implies the involvement, not only of mechanical compression, but also of chemical mediators which contribute to the generation of ectopic firing. The present study demonstrates that prostaglandin E2, a chemical mediator of inflammation, provoked the ectopic firing of nerve roots in a canine in vitro model which indicates that it may play a part in the irritation of nerve roots. In contrast, triamcinolone acetonide suppressed the firing induced by prostaglandin suggesting that steroids may be effective in the treatment of root symptoms.

  13. The Heavens on Fire

    NASA Astrophysics Data System (ADS)

    Littmann, Mark

    1998-10-01

    Meteor succeeded meteor in such rapid succession that it was impossible to count them; at times the sky seemed full of them, and the earth was illuminated as with a morning light. Eye-witness accounts such as this, and every spectacular detail of the Leonids, the greatest meteor showers of all, can be found in the acclaimed The Heavens on Fire. In this volume, author Mark Littmann vividly tells the history of meteors, and especially the Leonids, whose terrifying beauty established meteor science. He traces the history and mythology of meteors, profiles the fascinating figures whose discoveries advanced the field, and explores how meteors have changed the course of life on Earth. Crisp illustrations capture the excitement of past meteor showers and help elucidate important concepts. The returning Leonids are now reaching their peak with great activity expected in 1999 and 2000. For all those who wish to take part in this rare experience, Littmann offers advice on how and where to find the best view. Filled with practical tips, clear explanations, and descriptions of a sight that more than one observer has called "brilliant beyond conception," The Heavens on Fire will delight every reader. Mark Littmann teaches astronomy at the University of Tennessee. His previous books include Comet Halley: Once in a Lifetime and Planets Beyond: Discovering the Outer Solar System. Both books were chosen by the Astronomical Society of the Pacific as Astronomy Books of the Year.

  14. Fire monitoring from space: from research to operation

    NASA Astrophysics Data System (ADS)

    Pergola, Nicola; Filizzola, Carolina; Corrado, Rosita; Coviello, Irina; lacava, Teodosio; Marchese, Francesco; Mazzeo, Giuseppe; Paciello, Rossana; Tramutoli, Valerio

    2013-04-01

    Each summer fires rage through European forests, burning hundreds of thousands of hectares per year, as a result of the many (up to 60000) forest fires that usually occur annually in Europe. Fires can threaten public health and safety, destroy property and cause economic damages. Despite of their medium extension (the average burnt area is less than 6 ha), much smaller if compared with other regions like the USA and Canada, the number of simultaneous active fires in Europe can be very high, fomented by weather conditions that, especially in summer times and for countries of South Europe, are particularly favourable to a rapid and dramatic development of flames. Fires still are not only a social problem, but also an environmental emergency, producing a continuous impoverishment of forests and possibly indirectly triggering other natural hazards (e.g. making slopes, without the trees action, more prone to landslides). Additionally, there is a general concern about the loss of biodiversity and the contribution to land degradation that fires may cause. Earth Observation satellite systems have been largely tested for fire detection and monitoring from space. Their spectral capability, synoptic view and revisit times can offer an added value in the operational use not only in real time, during fires fighting activities, but also in near-real or delay time during the phases of risk management and mitigation. However, the practice of an actual operational use of satellite products by end-users is still not usual at European level. This work is based on the experience carried out jointly by CNR-IMAA and the National Civil Protection Department (DPC), in the framework of a five-year agreement in which the operational use of an Earth observation satellite system for fires spotting and monitoring is tested. Satellite-based products, developed not only for detecting fires but also for continuously monitoring their evolution in time domain, have been provided to Civil Protection

  15. Using VHF Lightning Observations to Monitor Explosive Volcanic Activity

    NASA Astrophysics Data System (ADS)

    Behnke, S. A.; Thomas, R. J.; McNutt, S. R.; Krehbiel, P. R.; Rison, W.; Edens, H. E.

    2011-12-01

    Lightning is an integral part of explosive volcanic eruptions and volcanic lightning measurements are a useful tool for volcano monitoring. VHF measurements of volcanic lightning can be made remotely, at distances of up to 100 km. A strategically placed network of 6 or more VHF ground stations could locate lightning in eruption columns from several regional volcanoes, and a minimum of two stations could be used to monitor a single volcano. Such a network would be particularly useful for detection or confirmation of explosive activity in situations where volcanoes are remotely located, and thus lack visual observations, or are not well instrumented with seismic networks. Furthermore, clouds are fully transparent to VHF signals, making lightning detection possible even when weather obscures visual observations. Recent VHF observations of volcanic lightning at Augustine Volcano (Alaska, USA, 2006), Redoubt Volcano (Alaska, USA, 2009) and Eyjafjallajökull (Iceland, 2010) have shown that two basic types of VHF signals are observed during volcanic eruptions, one of which is unique to volcanic activity. The unique signal, referred to as a 'continual RF' signal, was caused by very high rates of small 'vent discharges' occurring directly above the vent in the eruption column and was unlike any observations of lightning in meteorological thunderstorms. Vent discharges were observed to begin immediately following an explosive eruption. The second type of signal is from conventional lightning discharges, such as upward directed 'near-vent lightning' and isolated 'plume lightning.' Near-vent lightning was observed to begin 1-2 minutes following the onset of an explosive eruption while plume lightning began 4 or more minutes after the onset. At Redoubt the plume lightning occurred at such high rates that it rivaled lightning rates of supercell thunderstorms on the Great Plains of the United States. While both types of lightning signals can be used as indicators that explosive

  16. Both novelty and expertise increase action observation network activity

    PubMed Central

    Liew, Sook-Lei; Sheng, Tong; Margetis, John L.; Aziz-Zadeh, Lisa

    2013-01-01

    Our experiences with others affect how we perceive their actions. In particular, activity in bilateral premotor and parietal cortices during action observation, collectively known as the action observation network (AON), is modulated by one's expertise with the observed actions or individuals. However, conflicting reports suggest that AON activity is greatest both for familiar and unfamiliar actions. The current study examines the effects of different types and amounts of experience (e.g., visual, interpersonal, personal) on AON activation. fMRI was used to scan 16 healthy participants without prior experience with individuals with amputations (novices), 11 experienced occupational therapists (OTs) who had varying amounts of experience with individuals with amputations, and one individual born with below-elbow residual limbs (participant CJ), as they viewed video clips of goal-matched actions performed by an individual with residual limbs and by an individual with hands. Participants were given increased visual exposure to actions performed by both effectors midway through the scanning procedure. Novices demonstrated a large AON response to the initial viewing of an individual with residual limbs compared to one with hands, but this signal was attenuated after they received visual exposure to both effectors. In contrast, OTs, who had moderate familiarity with residual limbs, demonstrated a lower AON response upon initial viewing—similar to novices after they received visual exposure. At the other extreme, CJ, who has extreme familiarity with residual limbs both visually and motorically, shows a largely increased left-lateralized AON response, exceeding that of novices and experienced OTs, when viewing the residual limb compared to hand actions. These results suggest that a nuanced model of AON engagement is needed to explain how cases of both extreme experience (CJ) and extreme novelty (novices) can result in the greatest AON activity. PMID:24062656

  17. Initial analysis from a lidar observation campaign of sugar cane fires in the central and western portion of the São Paulo State, Brazil

    NASA Astrophysics Data System (ADS)

    da Silva Lopes, Fábio Juliano; Held, Gerhard; Nakaema, Walter M.; Rodrigues, Patricia F.; Bassan, Jose M.; Landulfo, Eduardo

    2011-11-01

    The central and western portion of the Sao Paulo State has large areas of sugar cane plantations, and due to the growing demand for biofuels, the production is increasing every year. During the harvest period some plantation areas are burnt a few hours before the manual cutting, causing significant quantities of biomass burning aerosol to be injected into the atmosphere. During August 2010, a field campaign has been carried out in Ourinhos, situated in the south-western region of Sao Paulo State. A 2-channel Raman Lidar system and two meteorological S-Band Doppler Radars are used to indentify and quantify the biomass burning plumes. In addiction, CALIPSO Satellite observations were used to compare the aerosol optical properties detected in that region with those retrieved by Raman Lidar system. Although the campaign yielded 30 days of measurements, this paper will be focusing only one case study, when aerosols released from nearby sugar cane fires were detected by the Lidar system during a CALIPSO overpass. The meteorological radar, installed in Bauru, approximately 110 km northeast from the experimental site, had recorded "echoes" (dense smoke comprising aerosols) from several fires occurring close to the Raman Lidar system, which also detected an intense load of aerosol in the atmosphere. HYSPLIT model forward trajectories presented a strong indication that both instruments have measured the same air masss parcels, corroborated with the Lidar Ratio values from the 532 nm elastic and 607 nm Raman N2 channel analyses and data retrieved from CALIPSO have indicated the predominance of aerosol from biomass burning sources.

  18. Facility Activation and Characterization for IPD Workhorse Preburner and Oxidizer Turbopump Hot-Fire Testing at NASA Stennis Space Center

    NASA Technical Reports Server (NTRS)

    Sass, J. P.; Raines, N. G.; Ryan, H. M.

    2004-01-01

    The Integrated Powerhead Demonstrator (IPD) is a 250K lbf (1.1 MN) thrust cryogenic hydrogen/oxygen engine technology demonstrator that utilizes a full flow staged combustion engine cycle. The Integrated Powerhead Demonstrator (IPD) is part of NASA's Next Generation Launch Technology (NGLT) program, which seeks to provide safe, dependable, cost-cutting technologies for future space launch systems. The project also is part of the Department of Defense's Integrated High Payoff Rocket Propulsion Technology (IHPRPT) program, which seeks to increase the performance and capability of today s state-of-the-art rocket propulsion systems while decreasing costs associated with military and commercial access to space. The primary industry participants include Boeing-Rocketdyne and GenCorp Aerojet. The intended full flow engine cycle is a key component in achieving all of the aforementioned goals. The IPD Program recently achieved a major milestone with the successful completion of the IPD Oxidizer Turbopump (OTP) hot-fire test project at the NASA John C. Stennis Space Center (SSC) E-1 test facility in June 2003. A total of nine IPD Workhorse Preburner tests were completed, and subsequently 12 IPD OTP hot-fire tests were completed. The next phase of development involves IPD integrated engine system testing also at the NASA SSC E-1 test facility scheduled to begin in late 2004. Following an overview of the NASA SSC E-1 test facility, this paper addresses the facility aspects pertaining to the activation and testing of the IPD Workhorse Preburner and the IPD Oxidizer Turbopump. In addition, some of the facility challenges encountered during the test project shall be addressed.

  19. Observations of Preflare Activity with TRACE and Yohkoh [Invited

    NASA Astrophysics Data System (ADS)

    Warren, H. P.

    2002-01-01

    Despite several decades of observational and theoretical effort, a complete understanding of solar flares remains elusive. It has been especially difficult to understand how the evolution of the magnetic field triggers a flare and drives the release of energy. In this talk I will review TRACE and Yohkoh observations of pre-flare and impulsive phase dynamics related to nonthermal broadening, flare ribbon evolution, and breakout reconnection. Studies of these phenomena suggest that pre-flare activity is a potentially rich source of information on the mechanisms that power a flare. For example, Yohkoh BCS measurements of nonthermal broadening have shown that the largest nonthermal velocities can occur before the onset of significant hard X-ray emission. This suggests that nonthermal broadening is a signature of a turbulent phase of the flare, which can begin several minutes before the onset of the hard x-ray emission. TRACE observations have also yielded evidence for ribbon brightenings that precede the onset of the hard X-ray emission. The analysis of very high cadence TRACE data, however, indicates that energy release during the pre-flare and impulsive phases of the flare is occurring on different loops. Finally, comparisons of pre-flare TRACE images with potential field extrapolations have shown that pre-flare activity associated with a null point in the field is an essential component of eruptive flares. Understanding the relationships between these phenomena will require coordinated observations between many instruments. I will discuss how future observations from Yohkoh, TRACE, SoHO, HESSI, Stereo, Solar-B, and ground-based observatories will be used to advance our understanding of flare physics.

  20. High Spatial Resolution Fe XII Observations of Solar Active Regions

    NASA Astrophysics Data System (ADS)

    Testa, Paola; De Pontieu, Bart; Hansteen, Viggo

    2016-08-01

    We use UV spectral observations of active regions with the Interface Region Imaging Spectrograph (IRIS) to investigate the properties of the coronal Fe xii 1349.4 Å emission at unprecedented high spatial resolution (˜0.33″). We find that by using appropriate observational strategies (i.e., long exposures, lossless compression), Fe xii emission can be studied with IRIS at high spatial and spectral resolution, at least for high-density plasma (e.g., post-flare loops and active region moss). We find that upper transition region (TR; moss) Fe xii emission shows very small average Doppler redshifts ({v}{{D}} ˜ 3 km s-1) as well as modest non-thermal velocities (with an average of ˜24 km s-1 and the peak of the distribution at ˜15 km s-1). The observed distribution of Doppler shifts appears to be compatible with advanced three-dimensional radiative MHD simulations in which impulsive heating is concentrated at the TR footpoints of a hot corona. While the non-thermal broadening of Fe xii 1349.4 Å peaks at similar values as lower resolution simultaneous Hinode Extreme Ultraviolet Imaging Spectrometer (EIS) measurements of Fe xii 195 Å, IRIS observations show a previously undetected tail of increased non-thermal broadening that might be suggestive of the presence of subarcsecond heating events. We find that IRIS and EIS non-thermal line broadening measurements are affected by instrumental effects that can only be removed through careful analysis. Our results also reveal an unexplained discrepancy between observed 195.1/1349.4 Å Fe xii intensity ratios and those predicted by the CHIANTI atomic database.

  1. The Fluid Mechanics of Fires

    NASA Astrophysics Data System (ADS)

    Baum, Howard

    2005-11-01

    The transport of heat and mass by fire induced flows is discussed with emphasis on the role of fire plumes. The fire plume provides the positive feedback mechanisms that determine the fire strength. It also acts as the pump which mixes the fuel and oxidizer distributes the combustion products in space and time. A brief description of some of the observed properties of isolated fire plumes in the laboratory is followed by a ``kinematic'' representation of plume fluid dynamics. In this model, entrainment is related to the vorticity and heat distributions generated by the fire. The utility of this approach is illustrated by appeal both to experiments on individual laboratory plumes and simulations of mass fires. The interaction of fire plumes with atmospheric winds is illustrated by a smoke dispersion model that couples a simplified description of the stratified atmosphere with a CFD based simulation of the large scale fire induced motions. Fire whirls are a rare but potentially catastrophic phenomenon controlled by the interaction of buoyancy with imposed angular momentum. An ``exact'' solution of the low Mach number combustion equations illustrates the changes induced by rotation. Finally, the simulation fire dynamics in enclosures is illustrated with results from the NIST investigation of the collapse of the World Trade Center towers.

  2. How will climate change affect wildland fire severity in the western US?

    NASA Astrophysics Data System (ADS)

    Parks, Sean A.; Miller, Carol; Abatzoglou, John T.; Holsinger, Lisa M.; Parisien, Marc-André; Dobrowski, Solomon Z.

    2016-03-01

    Fire regime characteristics in North America are expected to change over the next several decades as a result of anthropogenic climate change. Although some fire regime characteristics (e.g., area burned and fire season length) are relatively well-studied in the context of a changing climate, fire severity has received less attention. In this study, we used observed data from 1984 to 2012 for the western United States (US) to build a statistical model of fire severity as a function of climate. We then applied this model to several (n = 20) climate change projections representing mid-century (2040-2069) conditions under the RCP 8.5 scenario. Model predictions suggest widespread reduction in fire severity for large portions of the western US. However, our model implicitly incorporates climate-induced changes in vegetation type, fuel load, and fire frequency. As such, our predictions are best interpreted as a potential reduction in fire severity, a potential that may not be realized due human-induced disequilibrium between plant communities and climate. Consequently, to realize the reductions in fire severity predicted in this study, land managers in the western US could facilitate the transition of plant communities towards a state of equilibrium with the emerging climate through means such as active restoration treatments (e.g., mechanical thinning and prescribed fire) and passive restoration strategies like managed natural fire (under suitable weather conditions). Resisting changes in vegetation composition and fuel load via activities such as aggressive fire suppression will amplify disequilibrium conditions and will likely result in increased fire severity in future decades because fuel loads will increase as the climate warms and fire danger becomes more extreme. The results of our study provide insights to the pros and cons of resisting or facilitating change in vegetation composition and fuel load in the context of a changing climate.

  3. Recent burning of boreal forests exceeds fire regime limits of the past 10,000 years.

    PubMed

    Kelly, Ryan; Chipman, Melissa L; Higuera, Philip E; Stefanova, Ivanka; Brubaker, Linda B; Hu, Feng Sheng

    2013-08-06

    Wildfire activity in boreal forests is anticipated to increase dramatically, with far-reaching ecological and socioeconomic consequences. Paleorecords are indispensible for elucidating boreal fire regime dynamics under changing climate, because fire return intervals and successional cycles in these ecosystems occur over decadal to centennial timescales. We present charcoal records from 14 lakes in the Yukon Flats of interior Alaska, one of the most flammable ecoregions of the boreal forest biome, to infer causes and consequences of fire regime change over the past 10,000 y. Strong correspondence between charcoal-inferred and observational fire records shows the fidelity of sedimentary charcoal records as archives of past fire regimes. Fire frequency and area burned increased ∼6,000-3,000 y ago, probably as a result of elevated landscape flammability associated with increased Picea mariana in the regional vegetation. During the Medieval Climate Anomaly (MCA; ∼1,000-500 cal B.P.), the period most similar to recent decades, warm and dry climatic conditions resulted in peak biomass burning, but severe fires favored less-flammable deciduous vegetation, such that fire frequency remained relatively stationary. These results suggest that boreal forests can sustain high-severity fire regimes for centuries under warm and dry conditions, with vegetation feedbacks modulating climate-fire linkages. The apparent limit to MCA burning has been surpassed by the regional fire regime of recent decades, which is characterized by exceptionally high fire frequency and biomass burning. This extreme combination suggests a transition to a unique regime of unprecedented fire activity. However, vegetation dynamics similar to feedbacks that occurred during the MCA may stabilize the fire regime, despite additional warming.

  4. Long-term fire frequency not linked to prehistoric occupations in northern Swedish boreal forest.

    PubMed

    Carcaillet, Christopher; Bergman, Ingela; Delorme, Séverine; Hornberg, Greger; Zackrisson, Olle

    2007-02-01

    Knowledge of past fire regimes is crucial for understanding the changes in fire frequency that are likely to occur during the coming decades as a result of global warming and land-use change. This is a key issue for the sustainable management of forest biodiversity because fire regimes may be controlled by vegetation, human activities, and/or climate. The present paper aims to reconstruct the pattern of fire frequency over the Holocene at three sites located in the same region in the northern Swedish boreal forest. The fire regime is reconstructed from sedimentary charcoal analysis of small lakes or ponds. This method allows fire events to be characterized, after detrending the charcoal influx series, and allows estimation of the time elapsed between fires. The long-term fire regime, in terms of fire-free intervals, can thus be elucidated. At the three sites, the mean fire-free intervals through the Holocene were long and of similar magnitude (approximately 320 years). This similarity suggests that the ecological processes controlling fire ignition and spread were the same. At the three sites, the intervals were shorter before 8600 cal yr BP (calibrated years before present), between 7500 and 4500 cal yr BP, and after 2500 cal yr BP. Geomorphological and vegetation factors cannot explain the observed change, because the three sites are located in the same large ecological region characterized by Pinus sylvestris-Ericaceae mesic forests, established on morainic deposits at the same elevation. Archaeological chronologies also do not match the fire chronologies. A climatic interpretation is therefore the most likely explanation of the long-term regional pattern of fire. Although recent human activities between the 18th and the 20th centuries have clearly affected the fire regime, the dominant factor controlling it for 10000 years in northern Sweden has probably been climatic.

  5. Drivers of Recent Trends in African Landscape Fires

    NASA Astrophysics Data System (ADS)

    Andela, N.; van der Werf, G.

    2014-12-01

    Landscape fires play an important role in savannah ecosystem dynamics and are an important source of emissions of (greenhouse) gases and aerosols. Within the Monitoring Atmospheric Composition and Climate (MACC) project these fires are monitored using MODIS satellite data which now provides more than a decade of continuous observations. Africa is nowadays responsible for about 70% of global burned area and about 50% of fire carbon emissions, affecting regional air quality and global atmospheric composition. Although it has been reported that fire activity varies according to climatic and anthropogenic influences, much remains unclear about the drivers of the spatial distribution of fire activity over the African continent and its temporal dynamics. Resolving the drivers of this spatiotemporal variability is crucial to understand the future role of fire on the African continent. We developed a model to account for variations in fire activity due to climate, and investigated the role of sea surface temperatures on rainfall patterns and thus fire dynamics. Spatial variation and trends in cropland extent were used to improve understanding of underlying trends caused by socio-economic changes. Over 2001-2012, satellite observations indicate strong but opposing trends in the African hemispheres. Changes in precipitation, driven by the El Niño/Southern Oscillation (ENSO), which changed from El Niño to la Niña dominance over the study period, contributed substantially to the upward trend over southern Africa. This shift also contributed to the downward trend in northern Africa, but here rapid demographic and socio-economic developments contributed equally. Given the economic perspective of Africa and the oscillative nature of ENSO, future African savannah burned area will likely decline. Using MACC and GFED emissions estimates we expect that in the long term this decrease may be so substantial that forests may take over savannas as the main source of global fire

  6. Fire Power

    ERIC Educational Resources Information Center

    Denker, Deb; West, Lee

    2009-01-01

    For education administrators, campus fires are not only a distressing loss, but also a stark reminder that a campus faces risks that require special vigilance. In many ways, campuses resemble small communities, with areas for living, working and relaxing. A residence hall fire may raise the specter of careless youth, often with the complication of…

  7. Returning Fire

    ERIC Educational Resources Information Center

    Gould, Jon B.

    2007-01-01

    Last December saw another predictable report from the Foundation for Individual Rights in Education (FIRE), a self-described watchdog group, highlighting how higher education is supposedly under siege from a politically correct plague of so-called hate-speech codes. In that report, FIRE declared that as many as 96 percent of top-ranked colleges…

  8. Arizona Fires

    Atmospheric Science Data Center

    2014-05-15

    ... and is currently the second largest fire in Arizona history. More than 2,000 people are working to contain the fire, which is being ... bright desert background. The areas with no data (shown in black and present at the oblique angles) are locations where the variable ...

  9. California Fires

    Atmospheric Science Data Center

    2014-05-15

    article title:  Smoke Blankets Northern California     View Larger Image ... strikes sparked more than a thousand fires in northern California. This image was captured by the Multi-angle Imaging ... June 27, 2008 - Smoke from fires in northern California. project:  MISR category:  gallery ...

  10. The spatially varying influence of humans on fire probability in North America

    NASA Astrophysics Data System (ADS)

    Parisien, Marc-André; Miller, Carol; Parks, Sean A.; DeLancey, Evan R.; Robinne, François-Nicolas; Flannigan, Mike D.

    2016-07-01

    Humans affect fire regimes by providing ignition sources in some cases, suppressing wildfires in others, and altering natural vegetation in ways that may either promote or limit fire. In North America, several studies have evaluated the effects of society on fire activity; however, most studies have been regional or subcontinental in scope and used different data and methods, thereby making continent-wide comparisons difficult. We circumvent these challenges by investigating the broad-scale impact of humans on fire activity using parallel statistical models of fire probability from 1984 to 2014 as a function of climate, enduring features (topography and percent nonfuel), lightning, and three indices of human activity (population density, an integrated metric of human activity [Human Footprint Index], and a measure of remoteness [roadless volume]) across equally spaced regions of the United States and Canada. Through a statistical control approach, whereby we account for the effect of other explanatory variables, we found evidence of non-negligible human-wildfire association across the entire continent, even in the most sparsely populated areas. A surprisingly coherent negative relationship between fire activity and humans was observed across the United States and Canada: fire probability generally diminishes with increasing human influence. Intriguing exceptions to this relationship are the continent’s least disturbed areas, where fewer humans equate to less fire. These remote areas, however, also often have lower lightning densities, leading us to believe that they may be ignition limited at the spatiotemporal scale of the study. Our results suggest that there are few purely natural fire regimes in North America today. Consequently, projections of future fire activity should consider human impacts on fire regimes to ensure sound adaptation and mitigation measures in fire-prone areas.

  11. Calcium-Activated SK Channels Influence Voltage-Gated Ion Channels to Determine the Precision of Firing in Globus Pallidus Neurons

    PubMed Central

    Deister, Christopher A.; Chan, C. Savio; Surmeier, D. James; Wilson, Charles J.

    2012-01-01

    Globus pallidus (GP) neurons fire rhythmically in the absence of synaptic input, suggesting that they may encode their inputs as changes in the phase of their rhythmic firing. Action potential afterhyperpolarization (AHP) enhances precision of firing by ensuring that the ion channels recover from inactivation by the same amount on each cycle. Voltage-clamp experiments in slices showed that the longest component of the GP neuron’s AHP is blocked by apamin, a selective antagonist of calcium-activated SK channels. Application of 100 nm apamin also disrupted the precision of firing in perforated-patch and cell-attached recordings. SK channel blockade caused a small depolarization in spike threshold and made it more variable, but there was no reduction in the maximal rate of rise during an action potential. Thus, the firing irregularity was not caused solely by a reduction in voltage-gated Na+ channel availability. Subthreshold voltage ramps triggered a large outward current that was sensitive to the initial holding potential and had properties similar to the A-type K+ current in GP neurons. In numerical simulations, the availability of both Na+ and A-type K+ channels during autonomous firing were reduced when SK channels were removed, and a nearly equal reduction in Na+ and K+ subthreshold-activated ion channel availability produced a large decrease in the neuron’s slope conductance near threshold. This change made the neuron more sensitive to intrinsically generated noise. In vivo, this change would also enhance the sensitivity of GP neurons to small synaptic inputs. PMID:19571136

  12. Directory of workers in the fire field

    NASA Technical Reports Server (NTRS)

    Kuvshinoff, B. W.; Mcleod, S. B.; Katz, R. G.

    1973-01-01

    A directory was compiled to provide a list of workers engaged in fire research, their addresses and affiliations, and their principal fields of activity. The initial criteria for the selection of names for the directory are recent contributions to fire literature, teaching of subjects relevant to fire science, or participation in or support of fire research programs. With some exceptions, fire service personnel and fire protection engineers were excluded because directories already exist for these professionals. Also excluded are investigators engaged principally in studies of propulsion, combustion, and explosion phenomena, because these areas of study are somewhat aside from the main focus of fire research. For purposes of the directory, fire science is taken to be the body of knowledge, art, and skill related to the investigation, analysis, and interpretation of the phenomena of unwanted fires and the evaluation of materials methods, systems, and equipment related to fire safety, prevention, detection, and suppression.

  13. 46 CFR 28.315 - Fire pumps, fire mains, fire hydrants, and fire hoses.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Fire pumps, fire mains, fire hydrants, and fire hoses... After September 15, 1991, and That Operate With More Than 16 Individuals on Board § 28.315 Fire pumps, fire mains, fire hydrants, and fire hoses. (a) Each vessel 36 feet (11.8 meters) or more in length...

  14. 46 CFR 28.315 - Fire pumps, fire mains, fire hydrants, and fire hoses.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Fire pumps, fire mains, fire hydrants, and fire hoses... After September 15, 1991, and That Operate With More Than 16 Individuals on Board § 28.315 Fire pumps, fire mains, fire hydrants, and fire hoses. (a) Each vessel 36 feet (11.8 meters) or more in length...

  15. Geomorphology of coal seam fires

    NASA Astrophysics Data System (ADS)

    Kuenzer, Claudia; Stracher, Glenn B.

    2012-02-01

    . Finally, coal fire geomorphology helps to explain landscape features whose occurrence would otherwise not be understood. Although coal fire-induced thermal anomalies and gas release are also indications of coal fire activity, as addressed by many investigators, no assessment is complete without sound geomorphologic mapping of the fire-induced geomorphologic features.

  16. Forest Fire Smoke Layers Observed in the Free Troposphere over Portugal with a Multiwavelength Raman Lidar: Optical and Microphysical Properties

    PubMed Central

    Nepomuceno Pereira, Sérgio; Guerrero-Rascado, Juan Luis; Silva, Ana Maria; Wagner, Frank

    2014-01-01

    Vertically resolved optical and microphysical properties of biomass burning aerosols, measured in 2011 with a multiwavelength Raman lidar, are presented. The transportation time, within 1-2 days (or less), pointed towards the presence of relatively fresh smoke particles over the site. Some strong layers aloft were observed with particle backscatter and extinction coefficients (at 355 nm) greater than 5 Mm−1 sr−1 and close to 300 Mm−1, respectively. The particle intensive optical properties showed features different from the ones reported for aged smoke, but rather consistent with fresh smoke. The Ångström exponents were generally high, mainly above 1.4, indicating a dominating accumulation mode. Weak depolarization values, as shown by the small depolarization ratio of 5% or lower, were measured. Furthermore, the lidar ratio presented no clear wavelength dependency. The inversion of the lidar signals provided a set of microphysical properties including particle effective radius below 0.2 μm, which is less than values previously observed for aged smoke particles. Real and imaginary parts of refractive index of about 1.5-1.6 and 0.02i, respectively, were derived. The single scattering albedo was in the range between 0.85 and 0.93; these last two quantities indicate the nonnegligible absorbing characteristics of the observed particles. PMID:25114964

  17. Forest fire smoke layers observed in the free troposphere over Portugal with a multiwavelength Raman lidar: optical and microphysical properties.

    PubMed

    Nepomuceno Pereira, Sérgio; Preißler, Jana; Guerrero-Rascado, Juan Luis; Silva, Ana Maria; Wagner, Frank

    2014-01-01

    Vertically resolved optical and microphysical properties of biomass burning aerosols, measured in 2011 with a multiwavelength Raman lidar, are presented. The transportation time, within 1-2 days (or less), pointed towards the presence of relatively fresh smoke particles over the site. Some strong layers aloft were observed with particle backscatter and extinction coefficients (at 355 nm) greater than 5 Mm(-1)sr(-1) and close to 300 Mm(-1), respectively. The particle intensive optical properties showed features different from the ones reported for aged smoke, but rather consistent with fresh smoke. The Ångström exponents were generally high, mainly above 1.4, indicating a dominating accumulation mode. Weak depolarization values, as shown by the small depolarization ratio of 5% or lower, were measured. Furthermore, the lidar ratio presented no clear wavelength dependency. The inversion of the lidar signals provided a set of microphysical properties including particle effective radius below 0.2 μm, which is less than values previously observed for aged smoke particles. Real and imaginary parts of refractive index of about 1.5-1.6 and 0.02i, respectively, were derived. The single scattering albedo was in the range between 0.85 and 0.93; these last two quantities indicate the nonnegligible absorbing characteristics of the observed particles.

  18. Active region upflows. I. Multi-instrument observations

    NASA Astrophysics Data System (ADS)

    Vanninathan, K.; Madjarska, M. S.; Galsgaard, K.; Huang, Z.; Doyle, J. G.

    2015-12-01

    Context. We study upflows at the edges of active regions, called AR outflows, using multi-instrument observations. Aims: This study intends to provide the first direct observational evidence of whether chromospheric jets play an important role in furnishing mass that could sustain coronal upflows. The evolution of the photospheric magnetic field, associated with the footpoints of the upflow region and the plasma properties of active region upflows is investigated with the aim of providing information for benchmarking data-driven modelling of this solar feature. Methods: We spatially and temporally combine multi-instrument observations obtained with the Extreme-ultraviolet Imaging Spectrometer on board the Hinode, the Atmospheric Imaging Assembly and the Helioseismic Magnetic Imager instruments on board the Solar Dynamics Observatory and the Interferometric BI-dimensional Spectro-polarimeter installed at the National Solar Observatory, Sac Peak, to study the plasma parameters of the upflows and the impact of the chromosphere on active region upflows. Results: Our analysis shows that the studied active region upflow presents similarly to those studied previously, i.e. it displays blueshifted emission of 5-20 kms-1 in Fe xii and Fe xiii and its average electron density is 1.8 × 109 cm-3 at 1 MK. The time variation of the density is obtained showing no significant change (in a 3σ error). The plasma density along a single loop is calculated revealing a drop of 50% over a distance of ~20 000 km along the loop. We find a second velocity component in the blue wing of the Fe xii and Fe xiii lines at 105 kms-1 reported only once before. For the first time we study the time evolution of this component at high cadence and find that it is persistent during the whole observing period of 3.5 h with variations of only ±15 kms-1. We also, for the first time, study the evolution of the photospheric magnetic field at high cadence and find that magnetic flux diffusion is

  19. Multi-wavelength Observations of Solar Active Region NOAA 7154

    NASA Technical Reports Server (NTRS)

    Bruner, M. E.; Nitta, N. V.; Frank. Z. A.; Dame, L.; Suematsu, Y.

    2000-01-01

    We report on observations of a solar active region in May 1992 by the Solar Plasma Diagnostic Experiment (SPDE) in coordination with the Yohkoh satellite (producing soft X-ray images) and ground-based observatories (producing photospheric magnetograms and various filtergrams including those at the CN 3883 A line). The main focus is a study of the physical conditions of hot (T is approximately greater than 3 MK) coronal loops at their foot-points. The coronal part of the loops is fuzzy but what appear to be their footpoints in the transition region down to the photosphere are compact. Despite the morphological similarities, the footpoint emission at 10(exp 5) K is not quantitatively correlated with that at approximately 300 km above the tau (sub 5000) = 1 level, suggesting that the heat transport and therefore magnetic field topology in the intermediate layer is complicated. High resolution imaging observations with continuous temperature coverage are crucially needed.

  20. Inference of other's internal neural models from active observation.

    PubMed

    Kim, Kyung-Joong; Cho, Sung-Bae

    2015-02-01

    Recently, there have been several attempts to replicate theory of mind, which explains how humans infer the mental states of other people using multiple sensory input, with artificial systems. One example of this is a robot that observes the behavior of other artificial systems and infers their internal models, mapping sensory inputs to the actuator's control signals. In this paper, we present the internal model as an artificial neural network, similar to biological systems. During inference, an observer can use an active incremental learning algorithm to guess an actor's internal neural model. This could significantly reduce the effort needed to guess other people's internal models. We apply an algorithm to the actor-observer robot scenarios with/without prior knowledge of the internal models. To validate our approach, we use a physics-based simulator with virtual robots. A series of experiments reveal that the observer robot can construct an "other's self-model", validating the possibility that a neural-based approach can be used as a platform for learning cognitive functions.

  1. Dusty Winds in Active Galactic Nuclei: Reconciling Observations with Models

    NASA Astrophysics Data System (ADS)

    Hönig, Sebastian F.; Kishimoto, Makoto

    2017-04-01

    This Letter presents a revised radiative transfer model for the infrared (IR) emission of active galactic nuclei (AGNs). While current models assume that the IR is emitted from a dusty torus in the equatorial plane of the AGNs, spatially resolved observations indicate that the majority of the IR emission from ≲100 pc in many AGNs originates from the polar region, contradicting classical torus models. The new model CAT3D-WIND builds upon the suggestion that the dusty gas around the AGNs consists of an inflowing disk and an outflowing wind. Here, it is demonstrated that (1) such disk+wind models cover overall a similar parameter range of observed spectral features in the IR as classical clumpy torus models, e.g., the silicate feature strengths and mid-IR spectral slopes, (2) they reproduce the 3–5 μm bump observed in many type 1 AGNs unlike torus models, and (3) they are able to explain polar emission features seen in IR interferometry, even for type 1 AGNs at relatively low inclination, as demonstrated for NGC3783. These characteristics make it possible to reconcile radiative transfer models with observations and provide further evidence of a two-component parsec-scale dusty medium around AGNs: the disk gives rise to the 3–5 μm near-IR component, while the wind produces the mid-IR emission. The model SEDs will be made available for download.

  2. Observations on studies useful to asbestos operations and management activities

    SciTech Connect

    Wilmoth, R.C.; Powers, T.J.; Millette, J.R.

    1991-01-01

    Asbestos-containing materials found in buildings may release asbestos fibers into the air. Some of these fibers will eventually settle and attach to room surfaces (walls, furnishings, equipment, floors, and carpet) as part of normal dust. Activities like dusting, sweeping and vacuuming are likely to re-entrain the dust causing exposure to airborne asbestos. The paper discusses data that are largely observational in nature, but are illustrative of general trends of interest to those individuals dealing with the day-to-day problems of asbestos in buildings.

  3. VLBA Observations of AGN Activity in NGC 2617

    NASA Astrophysics Data System (ADS)

    Jencson, J.; Kundert, Kara; Mioduszewski, Amy; Lucy, Adrian; Kadowaki, Jennifer; Mellon, Samuel N.

    2013-08-01

    NGC 2617 is an active galaxy at z=0.0142 (~60 Mpc, 1 mas = 0.3 pc). A strong outburst was discovered by the All Sky Automated Survey for SuperNovae (ASAS-SN) in NGC 2617 at 2013 UT Apr. 10.27. A follow-up optical spectrum indicated a dramatic spectral type change from a Type 1.8 Seyfert to a Type 1 Seyfert within the last decade (Shappee et al. 2013, ATel #5010). Additional follow-up observations by Swift/BAT (Shappee et al.

  4. Seasonal Forecasting of Fires across Southern Borneo, 1997-2010

    NASA Astrophysics Data System (ADS)

    Spessa, Allan; Field, Robert; Kaiser, Johannes; Langner, Andreas; Moore, Jonathan; Pappenberger, Florian; Siegert, Florian; Weber, Ulrich

    2014-05-01

    several studies using historical data have established negative relationships between fires and antecedent rainfall, and/or positive relationships between fires and deforestation in regions affected by El Nino, comparatively little work has attempted to predict fires and emissions in such regions. Ensemble seasonal climate forecasts issued with several months lead-time have been applied to support risk assessment systems in many fields, notably agricultural production and natural disaster management of flooding, heat waves, drought and fire. The USA, for example, has a long-standing seasonal fire danger prediction system. Fire danger monitoring systems have been operating in Indonesia for over a decade, but, as of yet, no fire danger prediction systems exist. Given the effort required to mobilise suppression and prevention measures in Indonesia, one could argue that high fire danger periods must be anticipated months in advance for mitigation and response measures to be effective. To address this need, the goal of our work was to examine the utility of seasonal rainfall forecasts in predicting severe fires in Indonesia more than one month in advance, using southern Borneo (comprising the bulk of Kalimantan) as a case study. Here we present the results of comparing seasonal forecasts of monthly rainfall from ECMWF's System 4 against i) observed rainfall (GPCP), and ii) burnt area and deforestation (MODIS, AVHRR and Landsat) across southern Borneo for the period 1997-2010. Our results demonstrate the utility of using ECMWF's seasonal climate forecasts for predicting fire activity in the region. Potential applications include improved fire mitigation and responsiveness, and improved risk assessments of biodiversity and carbon losses through fire. These are important considerations for forest protection programmes (e.g. REDD+), forest carbon markets and forest (re)insurance enterprises.

  5. Research of Earthquake Potential from Active Fault Observation in Taiwan

    NASA Astrophysics Data System (ADS)

    Chien-Liang, C.; Hu, J. C.; Liu, C. C.; En, C. K.; Cheng, T. C. T.

    2015-12-01

    We utilize GAMIT/GLOBK software to estimate the precise coordinates for continuous GPS (CGPS) data of Central Geological Survey (CGS, MOEA) in Taiwan. To promote the software estimation efficiency, 250 stations are divided by 8 subnets which have been considered by station numbers, network geometry and fault distributions. Each of subnets include around 50 CGPS and 10 international GNSS service (IGS) stations. After long period of data collection and estimation, a time series variation can be build up to study the effect of earthquakes and estimate the velocity of stations. After comparing the coordinates from campaign-mode GPS sites and precise leveling benchmarks with the time series from continuous GPS stations, the velocity field is consistent with previous measurement which show the reliability of observation. We evaluate the slip rate and slip deficit rate of active faults in Taiwan by 3D block model DEFNODE. First, to get the surface fault traces and the subsurface fault geometry parameters, and then establish the block boundary model of study area. By employing the DEFNODE technique, we invert the GPS velocities for the best-fit block rotate rates, long term slip rates and slip deficit rates. Finally, the probability analysis of active faults is to establish the flow chart of 33 active faults in Taiwan. In the past two years, 16 active faults in central and northern Taiwan have been assessed to get the recurrence interval and the probabilities for the characteristic earthquake occurred in 30, 50 and 100 years.

  6. Observations on Multi-Slug Activity - Implications for Volcanic Processes

    NASA Astrophysics Data System (ADS)

    Pering, T. D.; McGonigle, A. J. S.; James, M. R.; Lane, S. J.; Capponi, A.; Tamburello, G.; Aiuppa, A.

    2014-12-01

    The study of single gas slugs in volcanic conduits has received a large amount of focus within the literature. However, the more complex behaviour associated with the rise and burst of multiple slugs has yet to be considered in detail in a volcanic context. Here we combine observations and analyses of such activity using a three-pronged approach consisting of existing gas mass data collected during rapid slug driven activity at Mt. Etna, scaled laboratory analogue experiments, and computer simulations using the Ansys Fluent® fluid dynamics software. Particular focus was applied to the process of coalescence and wake capture during slug expansion and rise. The results indicate a variety of potential features and relationships, including: promotion of coalescence at distances further than predicted wake lengths, approximate maximum gas volume fraction and minimum magma viscosity values for the occurrence of stable multi-slug activity, and in the laboratory regimes a series of linear trends are associated with overall gas volume fraction and burst volume. A previously observed phenomenon at Mt. Etna, whereby larger slug bursting events are subject to a longer repose period prior to the following event, than smaller events, is also evident in the lab setting. By combining all acquired and modelled data, we derive an approximate relation, using existing formulae for slug base rise speed (Viana et al. 2003) and wake length (Campos and Guedes de Carvalho, 1988), to describe a minimum repose period which is likely to follow the burst of a slug at the surface. The outlined work has significant fluid dynamic implications for possible magma and conduit properties which can allow multi-slug activity at volcanic targets.

  7. Research about the location technologies of forest fire detecting based on GIS

    NASA Astrophysics Data System (ADS)

    Zhang, An; Qi, Qingwen; Jiang, Lili; Guo, Chaohui

    2007-06-01

    Forest fire caused damages of property and loss of human life. Detecting a forest fire and get the location is very significant in the fire early warning. More early and more prompt detecting fire and determining fire position as far as possible could avoid and reduce loss of the disaster. At present there are three ways regarding the forest fire early warning and location determining which included: monitoring form Remote Sense Satellite image, manual observation and patrols, and automatic monitoring through CCD camera long-distance video. Overall evaluation regarding the three location technologies in forest fire early warning, the CCD camera detecting method is suitable in the fire rapid Response. An automatic forest fire surveillance system was running to detect the fire by using visible light images from the remote cameras. If a forest fire was detected, an alarm will be activated. The observation point elevation values, vertical offsets, horizontal and vertical scanning angles, and scanning distances will be also be sent to the central control room. The spatial orientation will be computed and showed on the electronic map. Key location technologies based on CCD camera included the image processing technique for automatically detecting forest fire and the visibility analyzes technique for the d