WorldWideScience

Sample records for total lightning activity

  1. Total Lightning Activity Associated with Tornadic Storms

    Science.gov (United States)

    Goodman, Steven J.; Buechler, Dennis; Hodanish, Stephen; Sharp, David; Williams, Earle; Boldi, Bob; Matlin, Anne; Weber, Mark

    1999-01-01

    Severe storms often have high flash rates (in excess of one flash per second) and are dominated by intracloud lightning activity. In addition to the extraordinary flash rates, there is a second distinguishing lightning characteristic of severe storms that seems to be important. When the total lightning history is examined, one finds sudden increases in the lightning rate, which we refer to as lightning "jumps," that precede the occurrence of severe weather by ten or more minutes. These jumps are typically 30-60 flashes/min, and are easily identified as anomalously large derivatives in the flash rate. This relationship is associated with updraft intensification and updraft strength is an important factor in storm severity (through the accumulation of condensate aloft and the stretching of vorticity). In several cases, evidence for diminishment of midlevel rotation and the descent of angular momentum from aloft is present prior to the appearance of the surface tornado. Based on our experience with severe and tornadic storms in Central Florida, we believe the total lightning may augment the more traditional use of NEXRAD radars and storm spotters. However, a more rigorous relation of these jumps to storm kinematics is needed if we are to apply total lightning in a decision tree that leads to improved warning lead times and decreased false alarm rates.

  2. Total Lightning Flash Activity Response to Aerosol over China Area

    Directory of Open Access Journals (Sweden)

    Pengguo Zhao

    2017-01-01

    Full Text Available Twelve years of measurements of aerosol optical depth (AOD, cloud fraction, cloud top height, ice cloud optical thickness and lightning flash density from 2001 to 2012 have been analyzed to investigate the effect of aerosols on electrical activity over an area of China. The results show that increasing aerosol loading inspires the convective intensity, and then increases the lightning flash density. The spatial distribution of the correlation between aerosol loading and electrical activity shows a remarkable regional difference over China. The high-correlation regions embody the positive aerosol microphysical effect on the intensity of the electrical activity, while the large-scale processes may play the main role in convection development and producing lightning in low-correlation regions.

  3. Using Total Lightning Observations to Enhance Lightning Safety

    Science.gov (United States)

    Stano, Geoffrey T.

    2012-01-01

    . SPoRT has been collaborating with the Huntsville National Weather Service (NWS) Office since 2003 and has since included several other offices to better implement LMA observations into real-time applications. Much of that work has focused on the LMA s ability to detect intra-cloud lightning in addition to cloud-to-ground lightning strikes. Combined, these observations are called total lightning. With total lightning observations, NWS offices can enhance their situational awareness and improve severe weather warnings. Just as importantly, the observed intra-cloud flashes often precede the first cloud-to-ground strike by a few minutes. SPoRT and its partner NWS offices are working to develop visualizations and applications to better utilize these data. However, there is a drawback. The LMAs have a short range of no more than 200 km. This is being addressed with the next generation geostationary satellite, GOES-R, which will boast the Geostationary Lightning Mapper (GLM). SPoRT, in conjunction with NOAA s GOES-R Proving Ground, is working to prepare the end user community for the GLM era using the LMA observations as a demonstration tool. Working collaboratively with our NWS partners, SPoRT is working to determine how best to integrate these future observations to improve both severe storm warnings and lightning safety.

  4. Lightning rod ionizing natural ionca - Ionic electrode active trimetallictriac of grounding - Definitive and total solution against 'blackouts' and electrical faults generated by atmospheric charges (lightning)

    Energy Technology Data Exchange (ETDEWEB)

    Cabareda, Luis

    2010-09-15

    The Natural Ionizing System of Electrical Protection conformed by: Lightning Rod Ionizing Natural Ionca and Ionic Electrode Active Trimetallic Triac of Grounding offers Total Protection, Maximum Security and Zero Risk to Clinics, Hospitals, Integral Diagnostic Center, avoiding ''the burning'' of Electronics Cards; Refineries, Tanks and Stations of Fuel Provision; Electrical Substations, Towers and Transmission Lines with transformer protection, motors, elevators, A/C, mechanicals stairs, portable and cooling equipment, electrical plants, others. This New High Technology is the solution to the paradigm of Benjamin Franklin and it's the mechanism to end the 'Blackouts' that produces so many damages and losses throughout the world.

  5. Total Lightning as an Indicator of Mesocyclone Behavior

    Science.gov (United States)

    Stough, Sarah M.; Carey, Lawrence D.; Schultz, Christopher J.

    2014-01-01

    Apparent relationship between total lightning (in-cloud and cloud to ground) and severe weather suggests its operational utility. Goal of fusion of total lightning with proven tools (i.e., radar lightning algorithms. Preliminary work here investigates circulation from Weather Suveilance Radar- 1988 Doppler (WSR-88D) coupled with total lightning data from Lightning Mapping Arrays.

  6. SAETTA: fine-scale observation of the total lightning activity in the framework of the CORSiCA atmospheric observatory

    Science.gov (United States)

    Coquillat, Sylvain; Defer, Eric; Lambert, Dominique; Martin, Jean-Michel; Pinty, Jean-Pierre; Pont, Véronique; Prieur, Serge

    2015-04-01

    Located in the West Mediterranean basin, Corsica is strategically positioned for atmospheric studies referred by MISTRALS/HyMeX and MISTRALS/CHARMEX programs. The implementation of the project of atmospheric observatory CORSiCA (supported by the Collectivité Territoriale de Corse via CPER/FEDER funds) was an opportunity to strengthen the potential observation of convective events causing heavy rainfall and flash floods, by acquiring a total lightning activity detection system adapted to storm tracking at a regional scale. This detection system called SAETTA (Suivi de l'Activité Electrique Tridimensionnelle Totale de l'Atmosphère) is a network of 12 LMA stations (Lightning Mapping Array). Developed by New Mexico Tech (USA), the instrument allows observing lightning flashes in 3D and real time, at high temporal and spatial resolutions. It detects the radiations emitted by cloud discharges in the 60-66 MHz band, in a radius of about 300 km from the centre of the network, in passive mode and standalone (solar panel and battery). Each LMA station samples the signal at high rate (80 microseconds), records data on internal hard disk, and transmits a decimated signal in real-time via the 3G phone network. The decimated data are received on a server that calculates the position of the detected sources by the time-of-arrival method and manages a quasi real-time display on a website. The non decimated data intended for research applications are recovered later on the field. Deployed in May and June 2014, SAETTA operated nominally from July 13 to October 20, 2014. It is to be definitively re-installed in spring 2015 after a hardware updating. The operation of SAETTA is contractually scheduled until the end of 2019, but it is planned to continue well beyond to obtain longer-term observations for addressing issues related to climatic trends. SAETTA has great scientific potential in a broad range of topics: physics of discharge; monitoring and simulation of storm systems

  7. Preliminary Results form the Japanese Total Lightning Network

    Science.gov (United States)

    Hobara, Y.; Ishii, H.; Kumagai, Y.; Liu, C.; Heckman, S.; Price, C. G.; Williams, E. R.

    2015-12-01

    We report on the initial observational results from the first Japanese Total Lightning Detection Network (JTLN) in relation to severe weather phenomena. The University of Electro-Communications (UEC) has deployed the Earth Networks (EN) Total Lightning System over Japan to carry out research on the relationship between thunderstorm activity and severe weather phenomena since 2013. In this paper we first demonstrate the current status of our new network followed by the initial scientific results. The lightning jump algorithm was applied to our total lightning data to study the relationship between total lighting activity and hazardous weather events such as gust fronts and tornadoes over land reported by the JMA (Japanese Meteorological Agency) in 2014. As a result, a clear increase in total lighting flash rate as well as lightning jumps are observed prior to most hazardous weather events (~20 min) indicating potential usefulness for early warning in Japan. Furthermore we are going to demonstrate the relationship of total lightning activities with meteorological radar data focusing particularly on Japanese Tornadic storms.

  8. An Operational Perspective of Total Lightning Information

    Science.gov (United States)

    Nadler, David J.; Darden, Christopher B.; Stano, Geoffrey; Buechler, Dennis E.

    2009-01-01

    The close and productive collaborations between the NWS Warning and Forecast Office, the Short Term Prediction and Research Transition Center at NASA Marshall Space Flight Center and the University of Alabama in Huntsville have provided a unique opportunity for science sharing and technology transfer. One significant technology transfer that has provided immediate benefits to NWS forecast and warning operations is the use of data from the North Alabama Lightning Mapping Array. This network consists of ten VHF receivers deployed across northern Alabama and a base station located at the National Space Science and Technology Center. Preliminary investigations done at WFO Huntsville, along with other similar total lightning networks across the country, have shown distinct correlations between the time rate-of-change of total lightning and trends in intensity/severity of the parent convective cell. Since May 2003 when WFO HUN began receiving these data - in conjunction with other more traditional remotely sensed data (radar, satellite, and surface observations) -- have improved the situational awareness of the WFO staff. The use of total lightning information, either from current ground based systems or future space borne instrumentation, may substantially contribute to the NWS mission, by enhancing severe weather warning and decision-making processes. Operational use of the data has been maximized at WFO Huntsville through a process that includes forecaster training, product implementation, and post event analysis and assessments. Since receiving these data, over 50 surveys have been completed highlighting the use of total lightning information during significant events across the Tennessee Valley. In addition, around 150 specific cases of interest have been archived for collaborative post storm analysis. From these datasets, detailed trending information from radar and total lightning can be compared to corresponding damage reports. This presentation will emphasize

  9. Assessing Operational Total Lightning Visualization Products

    Science.gov (United States)

    Stano, Geoffrey T.; Darden, Christopher B.; Nadler, David J.

    2010-01-01

    In May 2003, NASA's Short-term Prediction Research and Transition (SPoRT) program successfully provided total lightning data from the North Alabama Lightning Mapping Array (NALMA) to the National Weather Service (NWS) office in Huntsville, Alabama. The major accomplishment was providing the observations in real-time to the NWS in the native Advanced Weather Interactive Processing System (AWIPS) decision support system. Within days, the NALMA data were used to issue a tornado warning initiating seven years of ongoing support to the NWS' severe weather and situational awareness operations. With this success, SPoRT now provides real-time NALMA data to five forecast offices as well as working to transition data from total lightning networks at Kennedy Space Center and the White Sands Missile Range to the surrounding NWS offices. The only NALMA product that has been transitioned to SPoRT's partner NWS offices is the source density product, available at a 2 km resolution in 2 min intervals. However, discussions with users of total lightning data from other networks have shown that other products are available, ranging from spatial and temporal variations of the source density product to the creation of a flash extent density. SPoRT and the Huntsville, Alabama NWS are evaluating the utility of these variations as this has not been addressed since the initial transition in 2003. This preliminary analysis will focus on what products will best support the operational warning decision process. Data from 19 April 2009 are analyzed. On this day, severe thunderstorms formed ahead of an approaching cold front. Widespread severe weather was observed, primarily south of the Tennessee River with multiple, weak tornadoes, numerous severe hail reports, and wind. This preliminary analysis is the first step in evaluation which product(s) are best suited for operations. The ultimate goal is selecting a single product for use with all total lightning networks to streamline training and

  10. The GOES-R Geostationary Lightning Mapper (GLM) and the Global Observing System for Total Lightning

    Science.gov (United States)

    Goodman, Steven J.; Blakeslee, R. J.; Koshak, W.; Buechler, D.; Carey, L.; Chronis, T.; Mach, D.; Bateman, M.; Peterson, H.; McCaul, E. W., Jr.; hide

    2014-01-01

    for the existing GOES system currently operating over the Western Hemisphere. New and improved instrument technology will support expanded detection of environmental phenomena, resulting in more timely and accurate forecasts and warnings. Advancements over current GOES include a new capability for total lightning detection (cloud and cloud-to-ground flashes) from the Geostationary Lightning Mapper (GLM), and improved temporal, spatial, and spectral resolution for the next generation Advanced Baseline Imager (ABI). The GLM will map total lightning continuously day and night with near-uniform spatial resolution of 8 km with a product latency of less than 20 sec over the Americas and adjacent oceanic regions. This will aid in forecasting severe storms and tornado activity, and convective weather impacts on aviation safety and efficiency among a number of potential applications. The GLM will help address the National Weather Service requirement for total lightning observations globally to support warning decision-making and forecast services. Science and application development along with pre-operational product demonstrations and evaluations at NWS national centers, forecast offices, and NOAA testbeds will prepare the forecasters to use GLM as soon as possible after the planned launch and check-out of GOES-R in 2016. New applications will use GLM alone, in combination with the ABI, or integrated (fused) with other available tools (weather radar and ground strike networks, nowcasting systems, mesoscale analysis, and numerical weather prediction models) in the hands of the forecaster responsible for issuing more timely and accurate forecasts and warnings.

  11. Observations of Total Lightning Associated with Severe Convection During the Wet Season in Central Florida

    Science.gov (United States)

    Sharp, D.; Williams, E.; Weber, M.; Goodman, Steven J.; Raghavan, R.; Matlin, A.; Boldi, B.

    1998-01-01

    This paper will discuss findings of a collaborative lightning research project between National Aeronautics and Space Administration, the Massachusetts Institute of Technology and the National Weather Service office In Melbourne Florida. In August 1996, NWS/MLB received a workstation which incorporates data from the KMLB WSR-88D, Cloud to Ground (CG) stroke data from the National Lightning Detection Network (NLDN), and 3D volumetric lightning data collected from the Kennedy Space Centers' Lightning Detection And Ranging (LDAR) lightning system. The two primary objectives of this lightning workstation, called Lightning Imaging Sensor Data Applications Display (USDAD), are to: observe how total lightning relates to severe convective storm morphology over central Florida, and compare ground based total lightning data (LDAR) to a satellite based lightning detection system. This presentation will focus on objective #1. The LISDAD system continuously displays CG and total lighting activity overlaid on top of the KMLB composite reflectivity product. This allows forecasters to monitor total lightning activity associated with convective cells occurring over the central Florida peninsula and adjacent coastal waters. The LISDAD system also keeps track of the amount of total lightning data, and associated KMLB radar products with individual convective cells occurring over the region. By clicking on an individual cell, a history table displays flash rate information (CG and total lightning) in one minute increments, along with radar parameter trends (echo tops, maximum dBz and height of maximum dBz) every 5 minutes. This history table Is updated continuously, without user intervention, as long as the cell is identified. Reviewing data collected during the 1997 wet season (21 cases) revealed that storms which produced severe weather (hall greater or = 0.75 in. or wind damage) typically showed a rapid rise In total lightning prior to the onset of severe weather. On average, flash

  12. Assessments of Total Lightning Data Utility in Weather Forecasting

    Science.gov (United States)

    Buechler, Dennis E.; Goodman, Steve; LaCasse, Katherine; Blakeslee, Richard; Darden, Chris

    2005-01-01

    National Weather Service forecasters in Huntsville, Alabama have had access to total lightning data from the North Alabama Lightning Mapping Array (LMA) since 2003. Forecasters can monitor real-time total lightning observations on their AWIPS (Advanced Weather Interactive Processing System (AWIPS) workstations. The lightning data is used to supplement other observations such as radar and satellite data. The lightning data is updated every 2 min, providing more timely evidence of storm growth or decay than is available from 5 min radar scans. Total lightning observations have been used to positively impact warning decisions in a number of instances. A number of approaches are being pursued to assess the usefulness of total lightning measurements to the operational forecasting community in the warning decision process. These approaches, which include both qualitative and quantitative assessment methods, will be discussed. submitted to the American Meteorological Society (AMS) Conference on Meteorological Applications of Lightning Data to be held in San Diego, CA January 9-13,2005. This will be a presentation and an extended abstract will be published on a CD available from the AMS.

  13. Comparisons Between Total Lightning Data, Mesocyclone Strength, and Storm Damage Associated with the Florida Tornado Outbreak of February 23, 1998

    Science.gov (United States)

    Hodanish, S; Sharp, D.; Williams, E.; Boldi, B.; Goodman, Steven J.; Raghavan, R.; Matlin, A.; Weber, M.

    1998-01-01

    During the early morning hours of February 23 1998, the worst tornado outbreak ever recorded occurred over the central Florida peninsula. At least 7 confirmed tornadoes, associated with 4 supercells, developed, with 3 of the tornadoes reaching F3 intensity. Many of the tornadoes where on the ground for tens of miles, uncommon for the state of Florida. A total of 42 people were killed, with over 250 people injured. During the outbreak, National Weather Service Melbourne, in collaboration with the National Aeronautics and Space Administration and the Massachusetts Institute of Technology was collecting data from a unique lightning observing system called Lightning Imaging Sensor Data Applications Display (LISDAD, Boldi et.al., this conference). This system marries radar data collected from the KMLB WSR-88D, cloud to ground data collected from the National Lightning Detection Network, and total lightning data collected from NASKs Lightning Detection And Ranging system. This poster will display, concurrently, total lightning data (displayed in 1 minute increments), time/height storm relative velocity products from the KMLB WSR-88D, and damage information (tornado/hail/wind) from each of the supercell thunderstorms. The primary objective of this poster presentation is to observe how total lightning activity changes as the convective storm intensifies, and how the lightning activity changes with respect to mesocyclone strength (vortex stretching) and damaging weather on the ground.

  14. Characteristics of Lightning within Electrified Snowfall Events using Total Lightning Measurements

    Science.gov (United States)

    Schultz, C. J.; Bruning, E. C.; Lang, T. J.; Kuhlman, K. M.

    2015-12-01

    Lightning within heavy snowfall indicates the presence of heavy snowfall rates. Most studies within the literature examine this phenomenon using ground based networks that are primarily designed for identifying cloud to ground flashes. Thus, very little study of the three dimensional structure of the lightning flashes within heavy snowfall has been accomplished. Herein, total lightning mapping arrays, interferometers and ground based networks like the National Lightning Detection Network (NLDN) are utilized to document the characteristics of these flashes, including flash size, polarity, flash initiation location and inferred charge structure. A total of six events are examined, resulting in a total of approximately 80 flashes. Both individual case studies and overall population statistics will be used to characterize flashes within this winter environment. Many of these flashes are found to initiate from tall objects like television and radio communication towers, and come to ground in multiple locations along their path, resulting in one LMA derived flash containing multiple NLDN identified flashes. Cloud-to-ground flashes of both polarities are noted within the 80 flash sample. In one case, 3 separate flashes which resulted in ground flashes of both polarities were observed coming out of the same overall charge structure. This structure exhibited a highly sloped nature in the LMA data from east to west, and both +IC and -IC components of flashes were observed by the NLDN in the same region where the flashes initiated. A decrease in flash size is noted with time in at least three of these events due to weaker updraft (compared to their summertime thunderstorm counter parts) and smaller available of supercooled liquid water as inferred through trends in radar observations. These limiting factors are hypothesized to result in slower charging rates, and smaller flash sizes with time. Several flashes also exhibit sloped structures that match reflectivity

  15. GPM GROUND VALIDATION EARTH NETWORKS TOTAL LIGHTNING NETWORK (ENTLN) MC3E V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The Earth Networks Total Lightning Network (ENTLN) is an integrated in-cloud (IC) lightning and cloud-to-ground (CG) detection network deployed on a global basis...

  16. An Analysis of Total Lightning Flash Rates Over Florida

    Science.gov (United States)

    Mazzetti, Thomas O.; Fuelberg, Henry E.

    2017-12-01

    Although Florida is known as the "Sunshine State", it also contains the greatest lightning flash densities in the United States. Flash density has received considerable attention in the literature, but lightning flash rate has received much less attention. We use data from the Earth Networks Total Lightning Network (ENTLN) to produce a 5 year (2010-2014) set of statistics regarding total flash rates over Florida and adjacent regions. Instead of tracking individual storms, we superimpose a 0.2° × 0.2° grid over the study region and count both cloud-to-ground (CG) and in-cloud (IC) flashes over 5 min intervals. Results show that the distribution of total flash rates is highly skewed toward small values, whereas the greatest rate is 185 flashes min-1. Greatest average annual flash rates ( 3 flashes min-1) are located near Orlando. The southernmost peninsula, North Florida, and the Florida Panhandle exhibit smaller average annual flash rates ( 1.5 flashes min-1). Large flash rates > 100 flashes min-1 can occur during any season, at any time during the 24 h period, and at any location within the domain. However, they are most likely during the afternoon and early evening in East Central Florida during the spring and summer months.

  17. Variability of lightning activity over India on ENSO time scales

    Science.gov (United States)

    Ahmad, Adnan; Ghosh, Mili

    2017-12-01

    ENSO, the reliable indicator of inter-annual climate variation of the ocean-atmosphere system in the tropical Pacific region, can affect the overall lightning activity which is another atmospheric phenomenon. In the present study, the impact of the ENSO on the total lightning activity over India has been studied for the period 2004-2014. During the El-Nino period (July 2004-April 2005 and July 2009-April 2010), total number of lightning flashes increased by 10% and 18% respectively and during La-Nina period (July 2010-April 2011 and August 2011 to March 2012), the total number of lightning flashes decreased approximately by 19% and 28% respectively as compared to the mean of corresponding period (2004-14) of the Non-ENSO. Seasonal variation of flash density is also examined for the El-Nino and La-Nina period. The result shows that in the El-Nino period of the pre-monsoon and monsoon seasons, there is an increment in the flash density approximately by 48% and 9% respectively than the Non-ENSO and the spatial variation also having high flash density along the foot of Himalayas region. In the post-monsoon season, there is a marginal change in the flash density between El-Nino and the Non-ENSO. In the winter season, there is an increment in flash density in the El-Nino period approximately by 45% than the Non-ENSO. In the La-Nina period of the pre-monsoon and monsoon seasons, there is the decrement in the flash density approximately by the 44% and 24% respectively than the Non-ENSO. In the Post-monsoon season and winter season of La-Nina, the flash density is increased by about 24% and 33% over India. These findings can be applied to do proper planning of lightning induced hazard mitigation as lightning is of one of the major natural disasters of India.

  18. Response of lightning energy and total electron content with sprites over Antarctic Peninsula

    Science.gov (United States)

    Suparta, W.; Yusop, N.

    2017-05-01

    This paper investigates the response of the lightning energy with the total electron content (TEC) derived from GPS over Antarctic Peninsula during St Patrick’s geomagnetic storm. During this event, sprite as one of the mesospheric transient luminous events (TLEs) associated with positive cloud-to-ground (+CG) lightning discharges can be generated. In this work, GPS and lightning data for the period from 14 to 20 March 2015 is analyzed. Geomagnetic activity and electric field data are also processed to relate the geomagnetic storm and lightning. Results show that during St Patrick’s geomagnetic storm, the lighting energy was produced up to ∼257 kJ. The ionospheric TEC was obtained 60 TECU, 38 TECU and 78 TECU between 18:00 and 21:00 UT for OHI3, PALV and ROTH stations, respectively. The peak of lightning energy was observed 14 hours after peaked of TEC. Sprite possibly generated through the electrical coupling process between the top cloud, middle and upper atmosphere with the DC electric field found to be ∼10 mVm-1 which leading to the sprite generation after the return strokes on 18 March 2015.

  19. US COMPOSITE LIGHTNING DAILY TOTAL FROM NATL LIGHTNING NETWORK V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The Global Hydrology Resource Center generates a cloud-to-ground lightning product from the data collected from the U.S. National Lightning Detection Network, a...

  20. US COMPOSITE LIGHTNING 15MIN TOTAL FROM NATL LIGHTNING NETWORK V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The Lightning Imaging Sensor (LIS) Science Computing Facility (SCF) generates a cloud-to-ground lightning product from the data collected from the U.S. National...

  1. Polarimetric radar characteristics of storms with and without lightning activity

    Science.gov (United States)

    Mattos, Enrique V.; Machado, Luiz A. T.; Williams, Earle R.; Albrecht, Rachel I.

    2016-12-01

    This paper analyzes the cloud microphysics in different layers of storms as a function of three-dimensional total lightning density. A mobile X-band polarimetric radar and very high frequency (VHF) sources from Lightning Mapping Array (LMA) observations during the 2011/2012 Brazil spring-summer were used to determine the microphysical signatures of radar vertical profiles and lightning density. This study quantified the behavior of 5.3 million vertical profiles of the horizontal reflectivity (ZH), differential reflectivity (ZDR), specific differential phase (KDP), and correlation coefficient (ρHV). The principal changes in the polarimetric variables occurred only for VHF source rate density greater than 14 VHF sources per km2 in 4 min. These storms showed an enhanced positive KDP in the mixed 1 layer (from 0 to -15°C) probably associated with supercooled liquid water signatures, whereas regions with negative ZDR and KDP and moderate ZH in the mixed 2 layer (from -15 to -40°C) were possibly associated with the presence of conical graupel. The glaciated (above -40°C) and upper part of the mixed 2 layers showed a significant trend to negative KDP with an increase in lightning density, in agreement with vertical alignment of ice particle by the cloud electric field. A conceptual model that presents the microphysical signatures in storms with and without lightning activity was constructed. The observations documented in this study provide an understanding of how the combinations of polarimetric variables could help to identify storms with different lightning density and vice versa.

  2. Nowcasting and forecasting of lightning activity: the Talos project.

    Science.gov (United States)

    Lagouvardos, Kostas; Kotroni, Vassiliki; Kazadzis, Stelios; Giannaros, Theodore; Karagiannidis, Athanassios; Galanaki, Elissavet; Proestakis, Emmanouil

    2015-04-01

    Thunder And Lightning Observing System (TALOS) is a research program funded by the Greek Ministry of Education with the aim to promote excellence in the field of lightning meteorology. The study focuses on exploring the real-time observations provided by the ZEUS lightning detection system, operated by the National Observatory of Athens since 2005, as well as the 10-year long database of the same system. More precisely the main research issues explored are: - lightning climatology over the Mediterranean focusing on lightning spatial and temporal distribution, on the relation of lightning with topographical features and instability and on the importance of aerosols in lightning initiation and enhancement. - nowcasting of lightning activity over Greece, with emphasis on the operational aspects of this endeavour. The nowcasting tool is based on the use of lightning data complemented by high-time resolution METEOSAT imagery. - forecasting of lightning activity over Greece based on the use of WRF numerical weather prediction model. - assimilation of lightning with the aim to improve the model precipitation forecast skill. In the frame of this presentation the main findings of each of the aforementioned issues are highlighted.

  3. The relationship between total cloud lightning behavior and radar derived thunderstorm structure

    OpenAIRE

    Metzger, Eric L.

    2010-01-01

    Approved for public release; distribution is unlimited ng to other thunderstorm parameters. A relationship between total cloud lightning behavior and currently used radar interrogation techniques was found indicating lightning jumps can be classified into three different types. Two types show preponderance for a specific type of severe weather event and lightning behavior while the third show no preference. These findings are of significant interest to the operational meteorological commun...

  4. Lightning

    Science.gov (United States)

    Pampe, William R.

    1970-01-01

    Presents basic physical theory for movement of electric charges in clouds, earth, and air during production of lightning and thunder. Amount of electrical energy produced and heating effects during typical thunderstorms is described. Generalized safety practices are given. (JM)

  5. Total Lightning Characteristics with Respect to Radar-Derived Mesocyclone Strength

    Science.gov (United States)

    Stough, Sarah M.; Carey, Lawrence D.; Schultz, Christopher J.

    2015-01-01

    Recent work investigating the microphysical and kinematic relationship between a storm's updraft, its total lightning production, and manifestations of severe weather has resulted in development of tools for improved nowcasting of storm intensity. The total lightning jump algorithm, which identifies rapid increases in total lightning flash rate that often precede severe events, has shown particular potential to benefit warning operations. Maximizing this capability of total lightning and its operational implementation via the lightning jump may best be done through its fusion with radar and radar-derived intensity metrics. Identification of a mesocyclone, or quasi-steady rotating updraft, in Doppler velocity is the predominant radar-inferred early indicator of severe potential in a convective storm. Fused lightning-radar tools that capitalize on the most robust intensity indicators would allow enhanced situational awareness for increased warning confidence. A foundational step toward such tools comes from a better understanding of the updraft-centric relationship between intensification of total lightning production and mesocyclone development and strength. The work presented here utilizes a sample of supercell case studies representing a spectrum of severity. These storms are analyzed with respect to total lightning flash rate and the lightning jump alongside mesocyclone strength derived objectively from the National Severe Storms Laboratory (NSSL) Mesocyclone Detection Algorithm (MDA) and maximum azimuthal shear through a layer. Early results indicate that temporal similarities exist in the trends between total lightning flash rate and low- to mid-level rotation in supercells. Other characteristics such as polarimetric signatures of rotation, flash size, and cloud-to-ground flash ratio are explored for added insight into the significance of these trends with respect to the updraft and related processes of severe weather production.

  6. Characterizing wind turbine system response to lightning activity

    Energy Technology Data Exchange (ETDEWEB)

    McNiff, B.; LaWhite, N. [McNiff Light Industry, Harborside, ME (United States); Muljadi, E. [National Renewable Energy Lab., Golden, CO (United States)

    1998-07-01

    A lightning protection research program was instituted by National Renewable Energy Laboratory to minimize lightning damage to wind turbines and to further the understanding of effective damage mitigation techniques. To that end, a test program is under way to observe lightning activity, protection system response, and damage at a wind power plant in the Department of Energy (DOE) and Electric Power Research Institute (EPRI) Turbine Verification Program. The authors installed Lightning activated surveillance cameras along with a special storm tracking device to observe the activity in the wind plant area. They instrumented the turbines with lightning and ground current detection devices to log direct and indirect strike activity at each unit. They installed a surge monitor on the utility interface to track incoming activity from the transmission lines. Maintenance logs are used to verify damage and determine downtime and repair costs. Actual strikes to turbines were recorded on video and ancillary devices. The test setup and some results are discussed in this paper.

  7. Convective Induced Turbulence (CIT) Detection via Total Lightning Sensing, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — We proposes to build a prototype Convective-Induced Turbulence (CIT) hazard detection system based on total lightning sensing as an indicator of the location and...

  8. Forest fires caused by lightning activity in Portugal

    Science.gov (United States)

    Russo, Ana; Ramos, Alexandre M.; Benali, Akli; Trigo, Ricardo M.

    2017-04-01

    Wildfires in southern Europe have been causing in the last decades extensive economic and ecological losses and, even human casualties (e.g. Pereira et al., 2011). According to statistics provided by the EC-JRC European Forest Fires Information System (EFFIS) for Europe, the years of 2003 and 2007 represent the most dramatic fire seasons since the beginning of the millennium, followed by the years 2005 and 2012. These extreme years registered total annual burned areas for Europe of over 600.000 ha, reaching 800.000 ha in 2003. Over Iberia and France, the exceptional fire seasons registered in 2003 and 2005 were coincident respectively with one of the most severe heatwaves (Bastos et al., 2014) and droughts of the 20th century (Gouveia et al., 2009). On the other hand, the year 2007 was very peculiar as the area of the Peloponnese was struck by a severe winter drought followed by a subsequent wet spring, being also stricken by three heat heaves during summer and played a major role increasing the susceptibility of the region to wildfires (Gouveia et al., 2016). Some countries have a relatively large fraction of fires caused by natural factors such as lightning, e.g. northwestern USA, Canada, Russia. In contrast, Mediterranean countries such as Portugal has only a small percentage of fire records caused by lightning. Although significant uncertainties remain for the triggering mechanism for the majority of fires registered in the catalog, since they were cataloged without a likely cause. In this work we have used mainly two different databases: 1) the Portuguese Rural Fire Database (PRFD) which is representative of rural fires that have occurred in Continental Portugal, 2002-2009, with the original data provided by the National forestry Authority; 2) lightning discharges location which were extracted from the Portuguese Lightning Location System that has been in service since June of 2002 and is operated by the national weather service - Portuguese Institute for Sea

  9. Lightning activity during the 1999 Superior derecho

    Science.gov (United States)

    Price, Colin G.; Murphy, Brian P.

    2002-12-01

    On 4 July 1999, a severe convective windstorm, known as a derecho, caused extensive damage to forested regions along the United States/Canada border, west of Lake Superior. There were 665,000 acres of forest destroyed in the Boundary Waters Canoe Area Wilderness (BWCAW) in Minnesota and Quetico Provincial Park in Canada, with approximately 12.5 million trees blown down. This storm resulted in additional severe weather before and after the occurrence of the derecho, with continuous cloud-to-ground (CG) lightning occurring for more than 34 hours during its path across North America. At the time of the derecho the percentage of positive cloud-to-ground (+CG) lightning measured by the Canadian Lightning Detection Network (CLDN) was greater than 70% for more than three hours, with peak values reaching 97% positive CG lightning. Such high ratios of +CG are rare, and may be useful indicators of severe weather.

  10. A Total Lightning Perspective of the 20 May 2013 Moore, Oklahoma Supercell

    Science.gov (United States)

    Stano, Geoffrey T.; Schultz, Christopher J.; Carey, Lawrence D.; MacGorman, Don R.; Calhoun, Kristin M.

    2014-01-01

    In the early afternoon of 20 May 2013, a storm initiated to the west-southwest of Newcastle, Oklahoma. This storm would rapidly intensify into the parent supercell of the tornado that struck the city of Moore, Oklahoma. This article describes what contributions total lightning observations from the Oklahoma Lightning Mapping Array could provide to operational forecasters had these observations been available in real-time. This effort includes a focus on the GOES-R pseudo-geostationary lightning mapper demonstration product as well as the NASA SPoRT / Meteorological Development Laboratory's total lightning tracking tool. These observations and tools identified several contributions. Two distinct lightning jumps at 1908 and 1928 UTC provided a lead time of 19 minutes ahead of severe hail and 26 minutes ahead of the Moore, Oklahoma tornado's touchdown. These observations provide strong situational awareness to forecasters, as the lightning jumps are related to the rapid strengthening of the storm's updraft and mesocyclone and serve as a precursor to the stretching of the storm vortex ahead severe weather.

  11. Analysis of warm season thunderstorms using an object-oriented tracking method based on radar and total lightning data

    Directory of Open Access Journals (Sweden)

    T. Rigo

    2010-09-01

    Full Text Available Monitoring thunderstorms activity is an essential part of operational weather surveillance given their potential hazards, including lightning, hail, heavy rainfall, strong winds or even tornadoes. This study has two main objectives: firstly, the description of a methodology, based on radar and total lightning data to characterise thunderstorms in real-time; secondly, the application of this methodology to 66 thunderstorms that affected Catalonia (NE Spain in the summer of 2006. An object-oriented tracking procedure is employed, where different observation data types generate four different types of objects (radar 1-km CAPPI reflectivity composites, radar reflectivity volumetric data, cloud-to-ground lightning data and intra-cloud lightning data. In the framework proposed, these objects are the building blocks of a higher level object, the thunderstorm.

    The methodology is demonstrated with a dataset of thunderstorms whose main characteristics, along the complete life cycle of the convective structures (development, maturity and dissipation, are described statistically. The development and dissipation stages present similar durations in most cases examined. On the contrary, the duration of the maturity phase is much more variable and related to the thunderstorm intensity, defined here in terms of lightning flash rate. Most of the activity of IC and CG flashes is registered in the maturity stage. In the development stage little CG flashes are observed (2% to 5%, while for the dissipation phase is possible to observe a few more CG flashes (10% to 15%. Additionally, a selection of thunderstorms is used to examine general life cycle patterns, obtained from the analysis of normalized (with respect to thunderstorm total duration and maximum value of variables considered thunderstorm parameters. Among other findings, the study indicates that the normalized duration of the three stages of thunderstorm life cycle is similar in most thunderstorms

  12. An Overview of the Total Lightning Jump Algorithm: Past, Present and Future Work

    Science.gov (United States)

    Schultz, Christopher J.; Petersen, Walter A.; Carey, Lawrence D.; Deierling, Wiebke; Kessinger, Cathy

    2011-01-01

    Rapid increases in total lightning prior to the onset of severe and hazardous weather have been observed for several decades. These rapid increases are known as lightning jumps and can precede the occurrence of severe weather by tens of minutes. Over the past decade, a significant effort has been made to quantify lightning jump behavior in relation to its utility as a predictor of severe and hazardous weather. Based on a study of 34 thunderstorms that occurred in the Tennessee Valley, early work conducted in our group at Huntsville determined that it was indeed possible to create a reasonable operational lightning jump algorithm (LJA) based on a statistical framework relying on the variance behavior of the lightning trending signal. We the expanded this framework and tested several variance-related LJA configurations on a much larger sample of 87 severe and non severe thunderstorms. This study determined that a configuration named the "2(sigma)" algorithm had the most promise in development of the operational LJA with a probability of detection (POD) of 87%, a false alarm rate (FAR) of 33%, a Heidke Skill Score (HSS) of 0.75. The 2(sigma) algorithm was then tested on an even larger sample of 711 thunderstorms of all types from four regions of the country where total lightning measurement capability existed. The result was very encouraging.Despite the larger number of storms and the inclusion of different regions of the country, the POD remained high (79%), the FAR was low (36%) and HSS was solid (0.71). Average lead time from jump to severe weather occurrence was 20.65 minutes, with a standard deviation of +/- 15 minutes. Also, trends in total lightning were compared to cloud to ground (CG) lightning trends, and it was determined that total lightning trends had a higher POD (79% vs 66%), lower FAR (36% vs 54 %) and a better HSS (0.71 vs 0.55). From the 711-storm case study it was determined that a majority of missed events were due to severe weather producing

  13. Simulation of Quasi-Linear Mesoscale Convective Systems in Northern China: Lightning Activities and Storm Structure

    Science.gov (United States)

    Wanli, Li

    2017-04-01

    Two intense quasi-linear mesoscale convective systems (QLMCSs) in northern China were simulated using the WRF (Weather Research and Forecasting) model and the 3D-Var (three-dimensional variational) analysis system of the ARPS (Advanced Regional Prediction System) model. A new method in which the lightning density is calculated using both the precipitation and non-precipitation ice mass was developed to reveal the relationship between the lightning activities and QLMCS structures. Results indicate that, compared with calculating the results using two previous methods, the lightning density calculated using the new method presented in this study is in better accordance with observations. Based on the calculated lightning densities using the new method, it was found that most lightning activity was initiated on the right side and at the front of the QLMCSs, where the surface wind field converged intensely. The CAPE was much stronger ahead of the southeastward progressing QLMCS than to the back it, and their lightning events mainly occurred in regions with a large gradient of CAPE. Comparisons between lightning and non-lightning regions indicated that lightning regions featured more intense ascending motion than non-lightning regions; the vertical ranges of maximum reflectivity between lightning and non-lightning regions were very different; and the ice mixing ratio featured no significant differences between the lightning and non-lightning regions.

  14. Activity determination of the Am-241 radioactive lightning rods

    International Nuclear Information System (INIS)

    Dellamano, Jose C.; Minematsu, Denise; Potiens Jr, Ademar J.

    2008-01-01

    Full text: The radioactive lightning rods had been manufactured in Brazil up to 1989, when the Comissao Nacional de Energia Nuclear (CNEN) lifted the license for manufacture, commerce and installation of these devices. Since this date, the radioactive lightning rods have been replaced for conventional protection systems against electric discharges and have been sent to the institutes subordinated to the CNEN, amongst them the Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP). The radioactive lightning rods are constituted in its majority for a central metallic rod where the plates are mounted. Am-241 radioactive sources are fixed in these plates. The treatment of these devices is made in a glove box, where mechanically the sources are separate of the plates and connecting rods, placed in a metallic package and stored for posterior characterization, final packaging, intermediate storage and final disposal. In accordance with manufacturers information had been installed in Brazil, approximately 75,000 units with activities varying between 25 and 92 MBq. Preliminary studies were carried out in some of the 16,000 lightning rods received by the Laboratorio de Rejeitos Radioativos (LRR) of the IPEN-CNEN/SP, and demonstrated that the variation of the values of activity is very bigger. The implantation of a methodology for the radioisotope characterization of the Am-241 removed sources of the radioactive lightning rods is important because the isotope inventory is necessary for the certification of the processes considered for packaging and storage, besides being indispensable data for the final disposal. It is convenient mentioning that one is not about the determination of activity of a radioactive source with geometry and defined characteristics, but the implantation of a measure protocol for groups of sources that will be used in the routine tasks of the LRR. The current work presents the methodology developed for the radioisotope characterization of the Am

  15. The relationship of lightning activity and short-duation rainfall events during warm seasons over the Beijing metropolitan region

    Science.gov (United States)

    Wu, F.; Cui, X.; Zhang, D. L.; Lin, Q.

    2017-12-01

    The relationship between lightning activity and rainfall associated with 2925 short-duration rainfall (SDR) events over the Beijing metropolitan region (BMR) is examined during the warm seasons of 2006-2007, using the cloud-to-ground (CG) and intracloud (IC) lightning data from Surveillance et Alerte Foudre par Interférometrie Radioélectrique (SAFIR)-3000 and 5-min rainfall data from automatic weather stations (AWSs). To facilitate the analysis of the rainfall-lightning correlations, the SDR events are categorized into six different intensity grades according to their hourly rainfall rates (HRRs), and an optimal radius of 10 km from individual AWSs for counting their associated lightning flashes is used. Results show that the lightning-rainfall correlations vary significantly with different intensity grades. Weak correlations (R 0.4) are found in the weak SDR events, and 40-50% of the events are no-flash ones. And moderate correlation (R 0.6) are found in the moderate SDR events, and > 10-20% of the events are no-flash ones. In contrast, high correlations (R 0.7) are obtained in the SDHR events, and < 10% of the events are no-flash ones. The results indicate that lightning activity is observed more frequently and correlated more robust with the rainfall in the SDHR events. Significant time lagged correlations between lightning and rainfall are also found. About 80% of the SDR events could reach their highest correlation coefficients when the associated lightning flashes shift at time lags of < 25 min before and after rainfall begins. The percentages of SDR events with CG or total lightning activity preceding, lagging or coinciding with rainfall shows that (i) in about 55% of the SDR events lightning flashes preceded rainfall; (ii) the SDR events with lightning flashes lagging behind rainfall accounted for about 30%; and (iii) the SDR events without any time shifts accounted for the remaining 15%. Better lightning-rainfall correlations can be attained when time

  16. The relationship of lightning activity and short-duration rainfall events during warm seasons over the Beijing metropolitan region

    Science.gov (United States)

    Wu, Fan; Cui, Xiaopeng; Zhang, Da-Lin; Qiao, Lin

    2017-10-01

    The relationship between lightning activity and rainfall associated with 2925 short-duration rainfall (SDR) events over the Beijing metropolitan region (BMR) is examined during the warm seasons of 2006-2007, using the cloud-to-ground (CG) and intracloud (IC) lightning data from Surveillance et Alerte Foudre par Interférometrie Radioélectrique (SAFIR)-3000 and 5-min rainfall data from automatic weather stations (AWSs). An optimal radius of 10 km around selected AWSs is used to determine the lightning-rainfall relationship. The lightning-rainfall correlations vary significantly, depending upon the intensity of SDR events. That is, correlation coefficient (R 0.7) for the short-duration heavy rainfall (SDHR, i.e., ≥ 20 mm h- 1) events is found higher than that (R 0.4) for the weak SDR (i.e., 5-10 mm h- 1) events, and lower percentage of the SDHR events (< 10%) than the weak SDR events (40-50%) are observed with few flashes. Significant time-lagged correlations between lightning and rainfall are also found. About 80% of the SDR events could reach their highest correlation coefficients when the associated lightning flashes shift at time lags of < 25 min before and after rainfall begins. Those events with lightning preceding rainfall account for 50-60% of the total SDR events. Better lightning-rainfall correlations can be attained when time lags are incorporated, with the use of total (CG and IC) lightning data. These results appear to have important implications for improving the nowcast of SDHR events.

  17. Cloud-to-ground lightning activity in Colombia: A 14-year study using lightning location system data

    Science.gov (United States)

    Herrera, J.; Younes, C.; Porras, L.

    2018-05-01

    This paper presents the analysis of 14 years of cloud-to-ground lightning activity observation in Colombia using lightning location systems (LLS) data. The first Colombian LLS operated from 1997 to 2001. After a few years, this system was upgraded and a new LLS has been operating since 2007. Data obtained from these two systems was analyzed in order to obtain lightning parameters used in designing lightning protection systems. The flash detection efficiency was estimated using average peak current maps and some theoretical results previously published. Lightning flash multiplicity was evaluated using a stroke grouping algorithm resulting in average values of about 1.0 and 1.6 for positive and negative flashes respectively and for both LLS. The time variation of this parameter changes slightly for the years considered in this study. The first stroke peak current for negative and positive flashes shows median values close to 29 kA and 17 kA respectively for both networks showing a great dependence on the flash detection efficiency. The average percentage of negative and positive flashes shows a 74.04% and 25.95% of occurrence respectively. The daily variation shows a peak between 23 and 02 h. The monthly variation of this parameter exhibits a bimodal behavior typical of the regions located near The Equator. The lightning flash density was obtained dividing the study area in 3 × 3 km cells and resulting in maximum average values of 25 and 35 flashes km- 2 year- 1 for each network respectively. A comparison of these results with global lightning activity hotspots was performed showing good correlation. Besides, the lightning flash density variation with altitude shows an inverse relation between these two variables.

  18. Using Satellite Lightning Data as a Hands-On Activity for a Broad Audience

    Science.gov (United States)

    Sinclair, L.; Smith, T.; Smith, D. K.; Weigel, A. M.; Bugbee, K.; Leach, C.

    2017-12-01

    Satellite lightning data archived at the NASA Global Hydrology Resource Center Distributed Active Archive Center (GHRC DAAC) captures the number of lightning flashes occurring within four by four kilometer pixels around the world from January 1998 through October 2014. These data were measured by the Lightning Imaging Sensor (LIS) on the Tropical Rainfall Measuring Mission (TRMM) satellite. As an outreach effort to educate other on the use lightning measurements, the GHRC DAAC developed an interactive color-by-number poster showing accumulated lightning flashes around the world. As participants color the poster it reveals regions of maximum lightning flash counts across the Earth, including Lake Maracaibo in Catatumbo, Venezuela and a region in Congo, Africa. This hands-on activity is a bright, colorful, and inviting way to bring lightning data to a broad audience and can be used for people of many ages, including elementary-aged audiences up to adults.

  19. Results of sprites, lightning activities and thunderstorms in Chinese mainland

    Science.gov (United States)

    Yang, J.; Qie, X.; Feng, G.

    2009-12-01

    Sprites are large brief discharges above thunderstorms and have been observed in many countries of the world. Chinese Sprites Observation Campaign (CSOC) was conducted during the summer of 2007, and a total of 17 sprites were first observed over two thunderstorms. One of the sprites occurred on July 28 above a thunderstorm in Guan County and the center of the storm was about 272 km from the observation site. The other sprites were recorded at the late night of August 1 and in the early morning of August 2, the storm center was 315 km away. Characteristics of the observed sprites, lightning activities and thunderstorms were documented. In addition, comparative analysis of the sprites producing thunderstorms and the non-sprites producing thunderstorms were also presented. The results show that all of the observed sprites occurred in cluster, and their appearances were very different, including ‘columniform sprites’, ‘carrot sprites’ and ‘dancing sprites’, etc, which was not much different from the results obtained in other regions. The duration of the sprites varied from a minimum of 40 ms to a maximum of 160 ms with a mean value of 61 ms. All of the parental +CGs were positive and located in large stratiform regions with radar echo of 20-40 dBZ in the rear of the thunderstorms. The Doppler radar images indicated that comparatively large stratiform regions occurred in the sprites-producing thunderstorms. More cases are needed to test the validity and the universality of these conclusions.

  20. An Analysis of Operational Total Lightning Data During Long-Track Tornadoes

    Science.gov (United States)

    Carcione, Brian C.; Stano, Geoffrey T.

    2012-01-01

    The 27 April 2011 tornado outbreak brought three distinct waves of tornadic thunderstorms to portions of Mississippi, Alabama, Tennessee, and Georgia, striking the Tennessee Valley of north Alabama and southern Tennessee particularly hard. A total of 42 tornado paths were surveyed across the fourteen county area covered by the National Weather Service (NWS) forecast office in Huntsville, Alabama. Ten of these tornadoes were on the ground for at least 20 miles, two had total path lengths over 130 miles, and six tornadoes were classified as violent (EF-4 or EF-5 on the Enhanced Fujita Scale). Many of these tornadoes occurred within the domain of the North Alabama Lightning Mapping Array (NALMA), a ground-based total lightning detection network owned and operated by the NASA Marshall Space Flight Center. Since 2003, the NASA Short-term Prediction Research and Transition Center has supplied data from NALMA in real time to NWS forecast offices in Huntsville, Knoxville/Tri-Cities, Birmingham, and Nashville. Previous research has documented the utility of total lightning information in predicting tornadogenesis, particularly when combined with other remote sensing tools. Basic warning decision-making during events such as 27 April is not the most difficult part of the process; instead, the focus of warning meteorologists shifts to looking for changes in intensity or possible particularly dangerous situations, since doppler radar velocity data often cannot distinguish between weak and strong tornadoes. To that end, this research attempts to determine if any correlation exists between flash densities of the longest-tracked tornadoes over time, and the surveyed wind speeds of the tornadoes. The long-track EF-5 tornado which struck the Hackleburg, Phil Campbell, and Tanner communities in north Alabama was the primary focus of this research due to its intensity and extended life cycle. However, not all tornadoes were available for total lightning analysis due to widespread

  1. Solar 27-day rotational period detected in wide-area lightning activity in Japan

    Science.gov (United States)

    Miyahara, Hiroko; Higuchi, Chika; Terasawa, Toshio; Kataoka, Ryuho; Sato, Mitsuteru; Takahashi, Yukihiro

    2017-04-01

    A signal of the 27-day solar rotational period is often observed in cloud and lightning activities over the globe. Here we provide evidence of the 27-day periodicity of lightning activity in Japan using daily observational records of lightning for AD 1989-2015. The 27-day period is detected with 4.2 standard deviations, but only in wide-area lightning activity covering more than a 105 km2. The 27-day signal is more prominent around the maxima of solar decadal cycles.

  2. Solar 27-day rotational period detected in wide-area lightning activity in Japan

    Directory of Open Access Journals (Sweden)

    H. Miyahara

    2017-04-01

    Full Text Available A signal of the 27-day solar rotational period is often observed in cloud and lightning activities over the globe. Here we provide evidence of the 27-day periodicity of lightning activity in Japan using daily observational records of lightning for AD 1989–2015. The 27-day period is detected with 4.2 standard deviations, but only in wide-area lightning activity covering more than a 105 km2. The 27-day signal is more prominent around the maxima of solar decadal cycles.

  3. SAETTA: high resolution 3D mapping of the lightning activity around Corsica Island

    Science.gov (United States)

    Coquillat, Sylvain; Defer, Eric; Lambert, Dominique; Pinty, Jean-Pierre; Pont, Véronique; Prieur, Serge

    2017-04-01

    In the frame of the French atmospheric observatory CORSiCA (http://www.obs-mip.fr/corsica), a total lightning activity detection system called SAETTA (Suivi de l'Activité Electrique Tridimensionnelle Totale de l'Atmosphère) has been deployed in Corsica Island in order to strengthen the potential of observation of convective events causing heavy rainfall and flash floods in the West Mediterranean basin. SAETTA is a network of 12 LMA stations (Lightning Mapping Array) developed by New Mexico Tech (USA). The instrument allows observing lightning flashes in 3D and real time, at high temporal (80 µs) and spatial resolutions. It detects the radiations emitted by cloud discharges in the 60-66 MHz band, in a radius of about 350 km from the centre of the network, in passive mode and standalone (solar panel and batteries). Initially deployed in May 2014, SAETTA operated from July 13 to October 20 in 2014 and from April 19 to December 1st in 2015. It is now in permanent operation since 16 April 2016. Many high quality observations have been performed so far that provide an accurate location in space and time of the convective events. They also bring interesting dynamical and microphysical features of those events. For example the intensity of the convective surges, the transport of charged ice particles in the stratiform area of the thunderclouds can be deduced from SAETTA observations. Specific events have also been detected as well: bolts-from-the-blue, inter cloud discharges, high level discharges in convective but also in stratiform areas, inverted dipoles. The specific lightning patterns of 2015 illustrate the complex influence of the relief, probably via slope and valley winds over Corsica and via induced lee-side convergences over the sea. SAETTA is expected to operate for at least a decade over Corsica so it will participate to the calibration/validation of upcoming lightning detectors from space such as MTG-LI. It will also be a key instrument during the field

  4. Seasonal forecasting of lightning and thunderstorm activity in tropical and temperate regions of the world.

    Science.gov (United States)

    Dowdy, Andrew J

    2016-02-11

    Thunderstorms are convective systems characterised by the occurrence of lightning. Lightning and thunderstorm activity has been increasingly studied in recent years in relation to the El Niño/Southern Oscillation (ENSO) and various other large-scale modes of atmospheric and oceanic variability. Large-scale modes of variability can sometimes be predictable several months in advance, suggesting potential for seasonal forecasting of lightning and thunderstorm activity in various regions throughout the world. To investigate this possibility, seasonal lightning activity in the world's tropical and temperate regions is examined here in relation to numerous different large-scale modes of variability. Of the seven modes of variability examined, ENSO has the strongest relationship with lightning activity during each individual season, with relatively little relationship for the other modes of variability. A measure of ENSO variability (the NINO3.4 index) is significantly correlated to local lightning activity at 53% of locations for one or more seasons throughout the year. Variations in atmospheric parameters commonly associated with thunderstorm activity are found to provide a plausible physical explanation for the variations in lightning activity associated with ENSO. It is demonstrated that there is potential for accurately predicting lightning and thunderstorm activity several months in advance in various regions throughout the world.

  5. The impact of the Western Ghats on lightning activity on the western coast of India

    Science.gov (United States)

    Kamra, A. K.; Nair, A. A.

    2015-06-01

    The effect of the Western Ghats on the lightning activity across the west coast of India around the coastal metropolitan city of Mumbai during the 1998-2012 period is investigated using data from the Lightning Imaging Sensor (LIS) onboard the Tropical Rainfall Measuring Mission (TRMM) satellite. A land-sea contrast of an order of magnitude in the lightning activity is observed even in a small area across the western coast of India. The shape of a zone of high lightning activity formed almost parallel to the Western Ghats during the onset and withdrawal phases of monsoon, strongly suggests the effect of the Western Ghats in its formation. Seasonal variation of the lightning activity in this area and also in each of its four equal sectors (two each over the Arabian Sea and over land) is bi-annual with one peak each in the onset (May/June) and withdrawal months (September/October) of monsoon and a sharp dip to very low values during the monsoon months (July/August) of maximum seasonal rainfall. The lightning activity in each sector is found to increase over the 1998-2012 period. However, the increase in lightning activity over the sector containing Mumbai is found to be greater during the pre- and post-monsoon periods and smaller during the monsoon period as compared to an identical sector immediately south of it.

  6. Lightning Imaging Sensor (LIS) on the International Space Station (ISS): Launch, Installation, Activation, and First Results

    Science.gov (United States)

    Blakeslee, R. J.; Christian, H. J., Jr.; Mach, D. M.; Buechler, D. E.; Koshak, W. J.; Walker, T. D.; Bateman, M. G.; Stewart, M. F.; O'Brien, S.; Wilson, T. O.; Pavelitz, S. D.; Coker, C.

    2016-12-01

    Over the past 20 years, the NASA Marshall Space Flight Center, the University of Alabama in Huntsville, and their partners developed and demonstrated the effectiveness and value of space-based lightning observations as a remote sensing tool for Earth science research and applications, and, in the process, established a robust global lightning climatology. The observations included measurements from the Lightning Imaging Sensor (LIS) on the Tropical Rainfall Measuring Mission (TRMM) and its Optical Transient Detector (OTD) predecessor that acquired global observations of total lightning (i.e., intracloud and cloud-to-ground discharges) spanning a period from May 1995 through April 2015. As an exciting follow-on to these prior missions, a space-qualified LIS built as a flight-spare for TRMM will be delivered to the International Space Station (ISS) for a 2 year or longer mission, flown as a hosted payload on the Department of Defense (DoD) Space Test Program-Houston 5 (STP-H5) mission. The STP-H5 payload containing LIS is scheduled launch from NASA's Kennedy Space Center to the ISS in November 2016, aboard the SpaceX Cargo Resupply Services-10 (SpaceX-10) mission, installed in the unpressurized "trunk" of the Dragon spacecraft. After the Dragon is berth to ISS Node 2, the payload will be removed from the trunk and robotically installed in a nadir-viewing location on the external truss of the ISS. Following installation on the ISS, the LIS Operations Team will work with the STP-H5 and ISS Operations Teams to power-on LIS and begin instrument checkout and commissioning. Following successful activation, LIS orbital operations will commence, managed from the newly established LIS Payload Operations Control Center (POCC) located at the National Space Science Technology Center (NSSTC) in Huntsville, AL. The well-established and robust processing, archival, and distribution infrastructure used for TRMM was easily adapted to the ISS mission, assuring that lightning

  7. The effects of Sao Paulo urban heat island on lightning activity: Decadal analysis (1999-2009)

    Science.gov (United States)

    Bourscheidt, Vandoir; Pinto, Osmar; Naccarato, Kleber P.

    2016-05-01

    Eleven years of lightning data from the Brazilian Integrated National Lightning Detection Network were used to analyze the effects of the urban heat island (UHI) of Sao Paulo on lightning activity, extending the investigation of previous works. Cloud-to-ground lightning data were analyzed in both spatial and temporal perspectives, using different approaches: flash density, flash rate, thunderstorm hours (TH), and the cell initiation technique (CIT), which aims to identify the onset of thunderstorms. Land surface temperature (LST) from MODIS (Moderate Resolution Imaging Spectroradiometer) was used to analyze the UHI evolution over the years. MODIS data were validated using ground stations, distributed within the urban area. Different time intervals (seasonal and intraday) were used in an attempt to separate local convective systems from synoptic-scale events. The results indicate significant effects of the UHI (using LST) on THs and CIT. The CIT showed a nearly ring pattern, especially during the afternoon (14:00-18:00 LT) of summer months, reinforcing temperature contrast as a condition for storm initiation. The results also suggest an amplification of the UHI effects on thunderstorm activity by local factors (sea and country breeze, synoptic events, and terrain). Higher flash rates were also observed throughout the urban region, which influences the lightning density. Temporal analysis indicates that minimum temperature and lightning activity increase in wintertime. In summary, the results agree with previous studies about the UHI and indicate its importance on lightning occurrence, especially by increasing the temperature contrast and the instability in these regions.

  8. Lightning Activity in the City of SÃO Paulo in the Last 50 Years: a Case Study for the Relation Between Lightning and Global Warming

    Science.gov (United States)

    Pinto, I. R.

    2010-12-01

    The study of the impact of global warming on lightning activity is a key point to understand the impact of global warming on climate changes. However, no specific reference to future changes in lightning activity exists in the last 2007 Intergovernmental Panel on Climate Change (IPCC) report. Since the majority of global lightning activity occurs in the tropics, changes in future global lightning activity will depend on changes in the tropical climate. Nevertheless, the projections given by the contemporary General Circulation Models (GCMs) for the tropical climate have large uncertainties since the simulation of convection is heavily parameterised. This is because the typical scale of this process is smaller than the model resolution. Depending on the convection parameterization adopted it is possible to obtain an increase or, even, a decrease in the global lightning activity. Also a wide range in the spatial variability of the simulated lightning activity is found, attributed to the different parameterizations. Another approach to investigate the lightning-climate relationship is based on data for short periods in a given region, even considering that it may be influenced by factors such as topography, local atmospheric circulation patterns and ocean currents, among others, while not being related to surface temperature or moisture. This approach is used in this article, applied to the city of São Paulo. Thunderstorm, precipitation, temperature and moisture data for this city for the period from 1950 to 2000 obtained by two meteorological stations and lightning data for this city for the period from 1999 to 2007 obtained by the Brazilian Lightning Detection network (BrasilDat) were used in the analysis. In order to gain some insights into possible future changes in global lightning activity data in the city of São Paulo are analyzed and discussed in the context of two specific points: the hypothesis that a hotter and drier global climate predicted by most GCMs

  9. Seasonal prediction of lightning activity in North Western Venezuela: Large-scale versus local drivers

    Science.gov (United States)

    Muñoz, Á. G.; Díaz-Lobatón, J.; Chourio, X.; Stock, M. J.

    2016-05-01

    The Lake Maracaibo Basin in North Western Venezuela has the highest annual lightning rate of any place in the world (~ 200 fl km- 2 yr- 1), whose electrical discharges occasionally impact human and animal lives (e.g., cattle) and frequently affect economic activities like oil and natural gas exploitation. Lightning activity is so common in this region that it has a proper name: Catatumbo Lightning (plural). Although short-term lightning forecasts are now common in different parts of the world, to the best of the authors' knowledge, seasonal prediction of lightning activity is still non-existent. This research discusses the relative role of both large-scale and local climate drivers as modulators of lightning activity in the region, and presents a formal predictability study at seasonal scale. Analysis of the Catatumbo Lightning Regional Mode, defined in terms of the second Empirical Orthogonal Function of monthly Lightning Imaging Sensor (LIS-TRMM) and Optical Transient Detector (OTD) satellite data for North Western South America, permits the identification of potential predictors at seasonal scale via a Canonical Correlation Analysis. Lightning activity in North Western Venezuela responds to well defined sea-surface temperature patterns (e.g., El Niño-Southern Oscillation, Atlantic Meridional Mode) and changes in the low-level meridional wind field that are associated with the Inter-Tropical Convergence Zone migrations, the Caribbean Low Level Jet and tropical cyclone activity, but it is also linked to local drivers like convection triggered by the topographic configuration and the effect of the Maracaibo Basin Nocturnal Low Level Jet. The analysis indicates that at seasonal scale the relative contribution of the large-scale drivers is more important than the local (basin-wide) ones, due to the synoptic control imposed by the former. Furthermore, meridional CAPE transport at 925 mb is identified as the best potential predictor for lightning activity in the Lake

  10. Anomalous lightning activity over the Metropolitan Region of São Paulo due to urban effects

    Science.gov (United States)

    Farias, W. R. G.; Pinto, O., Jr.; Naccarato, K. P.; Pinto, I. R. C. A.

    2009-02-01

    A significant enhancement in the number of negative cloud-to-ground (CG) lightning and a decrease in the percentage of positive CG flashes are observed over the city of São Paulo, similar to observations in other large urban areas. Strong evidence indicates that this anomalous behavior results from several mechanisms related to the urban effect. In this paper, we investigated the importance of the air pollution using CG lightning data provided by the Brazilian lightning detection network (BrasilDAT) for a 6-year period (1999-2004). Due to the large variations in the CG lightning activity in response to different meteorological processes, it is not an easy task to infer the contribution of air pollution to the enhancement in the lightning activity. In order to overcome such difficulty, two approaches were considered: (1) the weekly variation of the number of days with lightning in comparison to the mean concentration of particulate matter (PM 10), as well as other thermodynamical parameters; (2) the variation of the number of CG flashes and the maximum storm flash rate per individual thunderstorm for different levels of pollution. The results of both analyses suggest that: first, the enhancement in the CG lightning activity during the week days over São Paulo metropolitan region is related to the PM 10 concentration (pollution); second, the PM 10 concentration tends to increase the lifetime of the storms and, in consequence, the number of flashes per storm, and not the flash rate of the thunderstorm; and third, the effect of the pollution in the enhancement of the CG lightning activity is probably less significant compared to the effect of the urban heat island.

  11. Analysis of thunderstorm and lightning activity associated with sprites observed during the EuroSprite campaigns

    DEFF Research Database (Denmark)

    Soula, S.; van der Velde, O.; Montanyà, J.

    2009-01-01

    -producing periods followed a maximum in the CG lightning activity and were characterized by a low CG flash rate with a high proportion of + CG flashes, typically around 50%. All sprites were associated with + CGs except one which was observed after a − CG as detected by the Météorage network. This − CG...... a subsequent CG flash (median value lightning process associated with a sprite consisted of 7 CG flashes....

  12. Sao Paulo Lightning Mapping Array (SP-LMA): Network Assessment and Analyses for Intercomparison Studies and GOES-R Proxy Activities

    Science.gov (United States)

    Bailey, J. C.; Blakeslee, R. J.; Carey, L. D.; Goodman, S. J.; Rudlosky, S. D.; Albrecht, R.; Morales, C. A.; Anselmo, E. M.; Neves, J. R.; Buechler, D. E.

    2014-01-01

    A 12 station Lightning Mapping Array (LMA) network was deployed during October 2011 in the vicinity of Sao Paulo, Brazil (SP-LMA) to contribute total lightning measurements to an international field campaign [CHUVA - Cloud processes of tHe main precipitation systems in Brazil: A contribUtion to cloud resolVing modeling and to the GPM (GlobAl Precipitation Measurement)]. The SP-LMA was operational from November 2011 through March 2012 during the Vale do Paraiba campaign. Sensor spacing was on the order of 15-30 km, with a network diameter on the order of 40-50km. The SP-LMA provides good 3-D lightning mapping out to 150 km from the network center, with 2-D coverage considerably farther. In addition to supporting CHUVA science/mission objectives, the SP-LMA is supporting the generation of unique proxy data for the Geostationary Lightning Mapper (GLM) and Advanced Baseline Imager (ABI), on NOAA's Geostationary Operational Environmental Satellite-R (GOES-R: scheduled for a 2015 launch). These proxy data will be used to develop and validate operational algorithms so that they will be ready to use on "day1" following the GOES-R launch. As the CHUVA Vale do Paraiba campaign opportunity was formulated, a broad community-based interest developed for a comprehensive Lightning Location System (LLS) intercomparison and assessment study, leading to the participation and/or deployment of eight other ground-based networks and the space-based Lightning Imaging Sensor (LIS). The SP-LMA data is being intercompared with lightning observations from other deployed lightning networks to advance our understanding of the capabilities/contributions of each of these networks toward GLM proxy and validation activities. This paper addresses the network assessment including noise reduction criteria, detection efficiency estimates, and statistical and climatological (both temporal and spatially) analyses for intercomparison studies and GOES-R proxy activities.

  13. The Impact of Active Conductors on Czech and Hungarian Lightning Protection Legislation

    Directory of Open Access Journals (Sweden)

    Jan Mikeš

    2013-01-01

    Full Text Available This paper summarizes the developmental conditions for the emergence of protection against lightning. It reviews the legislation especially in the Czech Republic over the last 15 years, and its application for active lightning conductors. The paper presents examples of the damage caused bylightning strikes on buildings protected by ESE lightning rods constructed using the French nationalstandard NFC 17-102 [1] and STN 34 1391 [2]. Installation of lightning conductors based on thesestandards is not, however, in accordance with the valid legislation in the Czech Republic and Hungary.In response to a growing number of ESE installations in the Czech Republic, it is vital to inform boththe broader professional publc and the lay public of cases involving failures of this type of lightningconductor.

  14. Lightning Imaging Sensor (LIS) on the International Space Station (ISS): Launch, Installation, Activation, and First Results

    Science.gov (United States)

    Blakeslee, R. J.; Christian, H. J., Jr.; Mach, D. M.; Buechler, D. E.; Wharton, N. A.; Stewart, M. F.; Ellett, W. T.; Koshak, W. J.; Walker, T. D.

    2017-12-01

    Over two decades, the NASA Marshall Space Flight Center, the University of Alabama in Huntsville, and their partners developed and demonstrated the effectiveness and value of space-based lightning observations as a remote sensing tool for Earth science research and applications, and, in the process, established a robust global lightning climatology. The Lightning Imaging Sensor (LIS) on the Tropical Rainfall Measuring Mission (TRMM) provided global observations of tropical lightning for an impressive 17 years before that mission came to a close in April 2015. Now a space-qualified LIS, built as the flight spare for TRMM, has been installed on the International Space Station (ISS) for a minimum two year mission following its SpaceX launch on February 19, 2017. The LIS, flown as a hosted payload on the Department of Defense Space Test Program-Houston 5 (STP-H5) mission, was robotically installed in an Earth-viewing position on the outside of the ISS, providing a great opportunity to not only extend the 17-year TRMM LIS record of tropical lightning measurements but also to expand that coverage to higher latitudes missed by the TRMM mission. Since its activation, LIS has continuously observed the amount, rate, and radiant energy lightning within its field-of-view as it orbits the Earth. A major focus of this mission is to better understand the processes which cause lightning, as well as the connections between lightning and subsequent severe weather events. This understanding is a key to improving weather predictions and saving lives and property here in the United States and around the world. The LIS measurements will also help cross-validate observations from the new Geostationary Lightning Mapper (GLM) operating on NOAA's newest weather satellite GOES-16. An especially unique contribution from the ISS platform will be the availability of real-time lightning data, especially valuable for operational forecasting and warning applications over data sparse regions such

  15. Packaging Waste and Hitting Home Runs: How Education and Lightning Strike Detection Technology Supports Company and Community Activities

    International Nuclear Information System (INIS)

    Deecke, T.A.; Hyde, J.V.; Hylko, J.M.

    2006-01-01

    The weather is the most significant and unmanageable variable when performing environmental remediation activities. This variable can contribute to the failure of a project in two ways: 1) severe injury to an employee or employees following a cloud-to-ground lightning strike without prior visual or audible warnings; and 2) excessive 'down time' associated with mobilization and demobilization activities after a false alarm (e.g., lightning was seen in the distance but was actually moving away from the site). Therefore, in order for a project to be successful from both safety and financial viewpoints, the uncertainties associated with inclement weather, specifically lightning, need to be understood to eliminate the element of surprise. This paper discusses educational information related to the history and research of lightning, how lightning storms develop, types of lightning, the mechanisms of lightning injuries and fatalities, and follow-up medical treatment. Fortunately, lightning storm monitoring does not have to be either costly or elaborate. WESKEM, LLC selected the Boltek StormTracker Lightning Detection System with the Aninoquisi Lightning 2000 TM software. This fixed system, used in combination with online weather web pages, monitors and alarms WESKEM, LLC field personnel in the event of an approaching lightning storm. This application was expanded to justify the purchase of the hand-held Sky Scan Lightning/Storm Detector Model P5 used by the Heath Youth Athletic Association (HYAA) which is a non-profit, charitable organization offering sports programs for the youth and young adults in the local community. Fortunately, a lightning injury or fatality has never occurred on a WESKEM Paducah project or an HYAA-sponsored event. Using these fixed and hand-held systems will continue to prevent such injuries from occurring in the foreseeable future. (authors)

  16. Lightning Activity Analyses with Respect to the SPCZ Location and to Surface Air Humidity Around Tahiti

    Science.gov (United States)

    Ortega, P.; Guignes, T.

    2006-12-01

    The South Pacific Convergence Zone (SPCZ) is located from the West Pacific warm pool and trends Southeast towards French Polynesia. The Island Climate Update monthly publishes the mean location deduced from the outgoing long-wave radiation anomalies or higher rainfall. On the other hand, the Wide World Lightning Location Network monthly provides data from which the lightning activity distribution in the 0°-30° South latitude and 150°-240° West longitude area can be drawn. Scanning this rectangle from West to East the location of the maximum lightning activity can be located versus the longitude. Fitting the location of these maximum with a polynomial function leads to a curve comparable with the monthly mean position of the SPCZ, showing that this band of cloudiness is the main source of lightning in this whole area. Besides, relations between surface atmospheric parameters, the number of thunder days and the number of flashes recorded around Tahiti have been analyzed using, the absolute humidity and the lightning activity recorded during the last nine years with the help of CIGRE Lightning Flash Counters. Since it is known that the cloud base is closely related to the boundary layer relative humidity, the aim of the analysis was to sort out a correlation between this parameter and the lightning activity. No correlation has been clearly put in evidence with the number of thunder days but the monthly mean values of the amount of flashes recorded exhibit similar oscillation with air humidity over a 9 year long period including the several phases of the ENSO.

  17. Numerical modeling of an intense precipitation event and its associated lightning activity over northern Greece

    Science.gov (United States)

    Pytharoulis, I.; Kotsopoulos, S.; Tegoulias, I.; Kartsios, S.; Bampzelis, D.; Karacostas, T.

    2016-03-01

    This study investigates an intense precipitation event and its lightning activity that affected northern Greece and primarily Thessaloniki on 15 July 2014. The precipitation measurement of 98.5 mm in 15 h at the Aristotle University of Thessaloniki set a new absolute record maximum. The thermodynamic analysis indicated that the event took place in an environment that could support deep thunderstorm activity. The development of this intense event was associated with significant low-level convergence and upper-level divergence even before its triggering and a positive vertical gradient of relative vorticity advection. The high resolution (1.667 km × 1.667 km) non-hydrostatic WRF-ARW numerical weather prediction model was used to simulate this intense precipitation event, while the Lightning Potential Index was utilized to calculate the potential for lightning activity. Sensitivity experiments suggested that although the strong synoptic forcing assumed primary role in the occurrence of intense precipitation and lightning activity, their spatiotemporal variability was affected by topography. The application of the very fine resolution topography of NASA Shuttle Radar Topographic Mission improved the simulated precipitation and the calculated lightning potential.

  18. Characteristics of cloud-to-ground lightning activity over Seoul, South Korea in relation to an urban effect

    OpenAIRE

    S. K. Kar; Y.-A. Liou; K.-J. Ha

    2007-01-01

    Cloud-to-ground (CG) lightning flash data collected by the lightning detection network installed at the Korean Meteorological Administration (KMA) have been used to study the urban effect on lightning activity over and around Seoul, the largest metropolitan city of South Korea, for the period of 1989–1999. Negative and positive flash density and the percentage of positive flashes have been calculated. Calculation reveals that an enhancement of approximately 60% and 42% are observed,...

  19. Enhancement of cloud-to-ground lightning activity over Taipei, Taiwan in relation to urbanization

    Science.gov (United States)

    Kar, S. K.; Liou, Y. A.

    2014-10-01

    Collecting the cloud-to-ground (CG) lightning flash data from Tai-Power Company of Taiwan, a long term study has been performed to investigate the enhancement of lightning activity in and around Taipei City, the largest metropolitan city of Taiwan, in relation to urbanization, for the period of 2005-2010. Results reveal that negative flash density is enhanced by approximately 64% while the positive flash density is enhanced by 48%, over and downwind of the city compared with other neighboring areas. On the other hand a decrease of nearly 24% in the percentage of positive flashes occurs over and downwind of Taipei compared to upwind values. We have also investigated the effect of urbanization on peak current of both polarities but no significant effect is noticed. Possible influence of urban particulate matter on the enhancement of CG lightning activity has been analyzed utilizing the annual averages of PM10 (particulate matter with aerodynamic diameter smaller than 10 μm) and SO2 (sulfur dioxide) concentrations data. Interesting results are found, indicating the higher concentrations of PM10 and SO2 contributes to the CG lightning enhancement. Both the concentrations exhibit a positive linear correlation with the percent change in CG flashes from the upwind to the urban area and from the upwind to the downwind area. However, the correlation coefficient for PM10 concentrations is comparatively much lower than SO2 concentrations. Positive correlations of 0.55 and 0.68 are found for the PM10 and SO2 concentrations, respectively, when compared separately with the percent change in CG flashes from the upwind to the downwind area, indicating the influence of aerosols on urban CG lightning enhancement. Hourly variation of lightning flashes show that the urban effects on CG lightning is prominent in the afternoon and early evening hours. The results obtained from the present analysis corroborate the results reported in the literature by other researchers.

  20. Total Lightning and Radar Storm Characteristics Associated with Severe Storms in Central Florida

    Science.gov (United States)

    Goodman, Steven J; Raghavan, R.; Buechler, Dennis; Hodanish, S.; Sharp, D.; Williams, E.; Boldi, B.; Matlin, A.; Weber, M.

    1998-01-01

    This paper examines the three dimensional characteristics of lightning flashes and severe storms observed in Central Florida during 1997-1998. The lightning time history of severe and tornadic storms were captured during the on-going ground validation campaign supporting the Lightning Imaging Sensor (LIS) experiment on the Tropical Rainfall Measuring Mission (TRMM). The ground validation campaign is a collaborative experiment that began in 1997 and involves scientists at the Global Hydrology and Climate Center, MIT/Lincoln Laboratories, and the NWS Forecast Office at Melbourne, FL. Lightning signatures that may provide potential early warning of severe storms are being evaluated by the forecasters at the NWS/MLB office. Severe storms with extreme flash rates sometimes exceeding 300 per minute and accompanying rapid increases in flash rate prior to the onset of the severe weather (hall, damaging winds, tornadoes) have been reported by Hodanish et al. and Williams et al. (1998-this conference). We examine the co-evolving changes in storm structure (mass, echo top, shear, latent heat release) and kinematics associated with these extreme and rapid flash rate changes over time. The flash frequency and density are compared with the three dimensional radar reflectivity structure of the storm to help interpret the possible mechanisms producing the extreme and rapidly increasing flash rates. For two tornadic storms examined thus far, we find the burst of lightning is associated with the development of upper level rotation in the storm. In one case, the lightning burst follows the formation of a bounded weak echo region (BWER). The flash rates diminish with time as the rotation develops to the ground in conjunction with the decent of the reflectivity core. Our initial findings suggest the dramatic increase of flash rates is associated with a sudden and dramatic increase in storm updraft intensity which we hypothesize is stretching vertical vorticity as well as enhancing the

  1. Geomagnetic and sunspot activity associations and ionospheric effects of lightning phenomena at Trivandrum near dip equator

    Science.gov (United States)

    Girish, T. E.; Eapen, P. E.

    2008-12-01

    From a study of thunder/lightning observations in Trivandrum (near dip equator) for selected years between 1853 and 2005, we could find an inverse relation of the same with sunspot activity and associations with enhancements in diurnal range of local geomagnetic declination. The results seem to suggest lightning-associated modulation of E-region dynamo currents in the equatorial ionosphere and the thunderstorm activity near dip equator probably acts as a moderator to regulate electric potential gradient changes in the global electric circuit due to solar activity changes.

  2. Comparison of lightning activity in the two most active areas of the Congo Basin

    Science.gov (United States)

    Kigotsi, Jean K.; Soula, Serge; Georgis, Jean-François

    2018-02-01

    A comparison of the lightning activity in the two most active areas (Area_max for the main maximum and Area_sec for the secondary maximum) of the Congo Basin is made with data obtained by the World Wide Lightning Location Network (WWLLN) during 2012 and 2013. Both areas of same size (5° × 5°) exhibit flash counts in a ratio of about 1.32 for both years and very different distributions of the flash rate density (FRD) with maximums in a ratio of 1.94 and 2.59 for 2012 and 2013, respectively. The FRD is much more widely distributed in Area_sec, which means the whole area contributes more or less equal to the lightning activity. The diurnal cycle is much more pronounced in Area_max than in Area_sec with a ratio between the maximum and the minimum of 15.4 and 4.7, respectively. However, the minimum and maximum of the hourly flash rates are observed roughly at the same time in both areas, between 07:00 and 09:00 UTC and between 16:00 and 17:00 UTC, respectively. In Area_sec the proportion of days with low lightning rate (0-1000 flashes per day) is much larger (˜ 45 % in 2013) compared to Area_max (˜ 23 % in 2013). In Area_max the proportion of days with moderate lightning rate (1001-6000 flashes per day) is larger (˜ 68.5 % in 2013) compared to Area_sec (˜ 46 % in 2013). The very intense convective events are slightly more numerous in Area_sec. In summary, the thunderstorm activity in Area_sec is more variable at different scales of time (annually and daily), in intensity and in location. Area_max combines two favourable effects for thunderstorm development, the convergence associated with the African easterly jet of the Southern Hemisphere (AEJ-S) and a geographic effect due to the orography and the presence of a lake. The location of the strong convection in Area_sec is modulated by the distance of westward propagation/regeneration of mesoscale convective systems (MCSs) in relation to the phase of Kelvin waves.

  3. Effects of lightning and other meteorological factors on fire activity in the North American boreal forest: implications for fire weather forecasting

    Directory of Open Access Journals (Sweden)

    D. Peterson

    2010-07-01

    Full Text Available The effects of lightning and other meteorological factors on wildfire activity in the North American boreal forest are statistically analyzed during the fire seasons of 2000–2006 through an integration of the following data sets: the MODerate Resolution Imaging Spectroradiometer (MODIS level 2 fire products, the 3-hourly 32-km gridded meteorological data from North American Regional Reanalysis (NARR, and the lightning data collected by the Canadian Lightning Detection Network (CLDN and the Alaska Lightning Detection Network (ALDN. Positive anomalies of the 500 hPa geopotential height field, convective available potential energy (CAPE, number of cloud-to-ground lightning strikes, and the number of consecutive dry days are found to be statistically important to the seasonal variation of MODIS fire counts in a large portion of Canada and the entirety of Alaska. Analysis of fire occurrence patterns in the eastern and western boreal forest regions shows that dry (in the absence of precipitation lightning strikes account for only 20% of the total lightning strikes, but are associated with (and likely cause 40% of the MODIS observed fire counts in these regions. The chance for ignition increases when a threshold of at least 10 dry strikes per NARR grid box and at least 10 consecutive dry days is reached. Due to the orientation of the large-scale pattern, complex differences in fire and lightning occurrence and variability were also found between the eastern and western sub-regions. Locations with a high percentage of dry strikes commonly experience an increased number of fire counts, but the mean number of fire counts per dry strike is more than 50% higher in western boreal forest sub-region, suggesting a geographic and possible topographic influence. While wet lightning events are found to occur with a large range of CAPE values, a high probability for dry lightning occurs only when 500 hPa geopotential heights are above ~5700 m and CAPE values are

  4. Initial observations of cloud-to-ground lightning activity in microburst producing storms

    Science.gov (United States)

    Buechler, Dennis E.; Goodman, Steven J.

    1988-01-01

    Preliminary observations of cloud-to-ground lightning activity associated with wet microburst producing storms observed during the summer of 1986 near Huntsville, AL are presented. Reflectivity and velocity measurements obtained from two 10 cm Doppler radars are used to identify and characterize the microburst windshears and their parent clouds. A four-station lightning location network is used to characterize the ground discharges produced by these storms. Results show cloud-to-ground flashes preceding the microburst onset by 0 - 28 minutes and suggest that any storm in a microburst environment that produces a discharge to ground has the potential to generate an intense downdraft.

  5. Activity determination of the Am-241 sources from radioactive lightning rods

    International Nuclear Information System (INIS)

    Minematsu, Denise; Dellamano, Jose Claudio; Ferreira, Robson de Jesus

    2009-01-01

    The authorization for manufacture commerce and installation of radioactive lightning rods, in Brazil, was lifted in 1989 by the National Nuclear Energy Commission - CNEN (Resolution no 4/89). Since this date, these devices have been replaced and have been sent to the Institutes subordinated to the CNEN, amongst them the Nuclear and Energy Research Institute - IPEN-CNEN/SP. Radioactive Waste Management Laboratory - RWML of the IPEN - CNEN/SP had received, approximately, 16,000 units up to the end of 2008. The radioactive lightning rod is constituted in its majority, for a central metallic rod, where two or three metallic plates are mounted. In these plates, on average, six Am-241 sources are fixed. The process used for the radioactive lightning rods treatment is the dismantling of the device and the withdrawal of the sources from the metallic plates. The activity values of the lightning rods sources, supplied by the manufacturers, vary from two to three orders of magnitude and therefore it is necessary to characterize these sources. This paper describes the methodology used to measure the actual activity of each Am-241 sources extracted from the radioactive lightning rods. The first step was to sample tens of Am-241 sources and carry out the activity measurements for further use in the system calibration. The equipment used in this first stage was a gamma spectrometer, previously calibrated with an Am-241 standard source, in agreement with the same arrangement and same geometry in the measures of the sources. Results show that there are sources with similar activity values of those supplied by the manufacturers, but there are also sources with no activity - or also activity very low compared with the expected value -, as well as sources contend other radionuclides. (author)

  6. Characteristics of lightning activity in tropical cyclones developed over North Indian Ocean basin during 2010-2015

    Science.gov (United States)

    Ranalkar, M. R.; Pawar, S. D.; Pradeep Kumar, P.

    2017-05-01

    The characteristics of lightning activity in tropical cyclones (TCs) over North Indian Ocean (NIO) are presented using sample of 21 TCs developed during 2010-2015 using TRMM and World Wide Lightning Location Network (WWLLN) datasets along with information from annual reports of Regional Specialized Meteorological Center (RSMC), New Delhi. The microphysical features such as Polarization Corrected Brightness Temperature (PCT), attenuation corrected reflectivity factor, Ice Water Path (IWP) play a pivotal role in development of convective systems within TCs. The TCs exhibited systematic variation in lightning flashes per day within 300 km of estimated center during their life cycle irrespective of their severity and flash rate within 300 km of storm center. The lightning flashes ranged from 1 to 3500 flashes per day during pre-cyclone stage, 100 to 8000 flashes per day during cyclone stage and 0 to 4300 flashes per day during post-cyclone stage. The TCs produced maximum flash density in eyewall region (20-40 km) and outer rainband region (200-260 km). The WWLLN recorded 165,512 flashes within 300 km of TC centers during their life cycle. The maximum flashes occurred during cyclone stage followed by pre-cyclone and post-cyclone. The time variation of flash rate for all cyclones was episodic and primarily peaked during late night and early morning hours. The diurnal variation of lightning flashes during TCs due to variation in detection efficiency of WWLLN also controls temporal distribution of lightning activity. During rapid intensification, TCs produced profuse lightning flashes per hour. Episodic lightning flashes per hour occurred during weakening stage and prior to landfall. It is evident that outbreaks of lightning flashes prior to maximum intensity change as manifested in maximum sustained wind speed and fall in estimated central pressure (ECP) indicate potential predictive value of lightning activity for TC intensity change.

  7. Seasonal and diurnal variation of lightning activity over southern Africa and correlation with European whistler observations

    Directory of Open Access Journals (Sweden)

    A. B. Collier

    2006-03-01

    Full Text Available Lightning Imaging Sensor (LIS data have been analysed to ascertain the statistical pattern of lightning occurrence over southern Africa. The diurnal and seasonal variations are mapped in detail. The highest flash rates (107.2 km-2 y-1 occur close to the equator but maxima are also found over Madagascar (32.1 km-2 y-1 and South Africa (26.4 km-2 y-1. A feature of the statistics is a relatively steady contribution from over the ocean off the east coast of South Africa that appears to be associated with the Agulhas current. Lightning statistics are of intrinsic meteorological interest but they also relate to the occurrence of whistlers in the conjugate region. Whistler observations are made at Tihany, Hungary. Statistics reveal that the period of most frequent whistler occurrence does not correspond to the maximum in lightning activity in the conjugate region but is strongly influenced by ionospheric illumination and other factors. The whistler/flash ratio, R, shows remarkable variations during the year and has a peak that is narrowly confined to February and March.

  8. Evidence for the influence of land uses and soil types on cloud-to-ground lightning activity in Asturias (Spain)

    Science.gov (United States)

    Sisniega, David Prieto; García, Manuel Mora; Menéndez, Susana Fernández; Soriano, Luís Rivas; de Pablo Dávila, Fernando

    2018-05-01

    The present study analyses the impact of the different categories of land use and types of soils on cloud-to-ground (CG) lightning activity in the region of Asturias (Spain). Thirteen (fifteen) land uses (types of soils) and a range of fourteen years (2000 to 2013) of CG-lightning flash data were considered to complete the study. Some areas that have suffered the strong impact of human activity (urban, mining, and industrial) were associated with the increase of CG-lightning activity. When considering vegetated areas, areas with non-agricultural vegetation, arable land and permanent crops, it was showed a greater CG activity. With reference to the types of soils, Fluvisols, Regosols/Cambic-Arenosols, and Luvisols, these seemed to be associated to the increase of CG-lightning activity. The results found for the region of Asturias are different from those reported by Mora et al. (2015) for the region of Castilla y Leon (Spain).

  9. Role of drop distortion in enhancing the lightning activity in clouds formed over cities

    Science.gov (United States)

    Bhalwankar, Rohini; Kamra, A. K.

    2013-03-01

    Atmospheric pollutants can modify the electrification and lightning activity in thunderclouds. Laboratory simulation experiments show that distortion of water drops is more when drops are formed from water polluted with Sulfate/Nitrate salts than that from distilled water and the difference in distortions is more in a higher electric field. Further, the polluted water drops falling in a horizontal electric field can trigger a discharge on their surface and the discharge can propagate as a streamer in lower electric fields as compared to that from distilled water drops. The difference in electrical conductivities of polluted and unpolluted water drops is most likely the key factor for manifestation of these differences. It is proposed that the enhanced distortion of polluted drops coupled with the change in their characteristics to trigger and propagate a discharge in lower electric fields may significantly contribute to the enhancement of lightning activity observed in clouds formed over big cities.

  10. Relationship between median intensities of electromagnetic emissions in the VLF range and lightning activity

    Czech Academy of Sciences Publication Activity Database

    Němec, František; Santolík, Ondřej; Parrot, M.; Rodger, C. J.

    2010-01-01

    Roč. 115, - (2010), A08315/1-A08315/10 ISSN 0148-0227 R&D Projects: GA ČR GA205/09/1253; GA ČR GAP205/10/2279; GA MŠk ME09107 Institutional research plan: CEZ:AV0Z30420517 Keywords : lightning activity * VLF electromagnetic waves * DEMETER satellite Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 3.303, year: 2010

  11. Pre-Launch GOES-R Risk Reduction Activities for the Geostationary Lightning Mapper

    Science.gov (United States)

    Goodman, S. J.; Blakeslee, R. J.; Boccippio, D. J.; Christian, H. J.; Koshak, W. J.; Petersen, W. A.

    2005-01-01

    The GOES-R Geostationary Lightning Mapper (GLM) is a new instrument planned for GOES-R that will greatly improve storm hazard nowcasting and increase warning lead time day and night. Daytime detection of lightning is a particularly significant technological advance given the fact that the solar illuminated cloud-top signal can exceed the intensity of the lightning signal by a factor of one hundred. Our approach is detailed across three broad themes which include: Data Processing Algorithm Readiness, Forecast Applications, and Radiance Data Mining. These themes address how the data will be processed and distributed, and the algorithms and models for developing, producing, and using the data products. These pre-launch risk reduction activities will accelerate the operational and research use of the GLM data once GOES-R begins on-orbit operations. The GLM will provide unprecedented capabilities for tracking thunderstorms and earlier warning of impending severe and hazardous weather threats. By providing direct information on lightning initiation, propagation, extent, and rate, the GLM will also capture the updraft dynamics and life cycle of convective storms, as well as internal ice precipitation processes. The GLM provides information directly from the heart of the thunderstorm as opposed to cloud-top only. Nowcasting applications enabled by the GLM data will expedite the warning and response time of emergency management systems, improve the dispatch of electric power utility repair crews, and improve airline routing around thunderstorms thereby improving safety and efficiency, saving fuel and reducing delays. The use of GLM data will assist the Bureau of Land Management (BLM) and the Forest Service in quickly detecting lightning ground strikes that have a high probability of causing fires. Finally, GLM data will help assess the role of thunderstorms and deep convection in global climate, and will improve regional air quality and global chemistry/climate modeling

  12. Applicability of ultralow-frequency global resonances for investigating lightning activity on Venus

    International Nuclear Information System (INIS)

    Nikolaenko, A.P.; Rabinovich, L.M.

    1987-01-01

    The application to experiments on Venus of methods of investigating global lightning activity that are used on earth in the ultralow-frequency range is discussed. Calculations of the electromagnetic fields in the range from a few Hertz to tens of Hertz are carried out in the framework of the model of the lower ionosphere of Venus, which generalizes the information about the planet's atmosphere which is presently available. The calculations showed that observations of global resonances on Venus must, as on the earth, allow one to obtain data about the global distribution of lightning in space and time, and to make the values of the parameters of the lower ionosphere model more precise

  13. Effect of bacterial ice nuclei on the frequency and intensity of lightning activity inferred by the BRAMS model

    Directory of Open Access Journals (Sweden)

    F. L. T. Gonçalves

    2012-07-01

    Full Text Available Many studies from the last decades have shown that airborne microorganisms can be intrinsically linked to atmospheric processes. Certain bacteria may constitute the most active ice nuclei found in the atmosphere and might have some influence on the formation of ice crystals in clouds. This study deals with the ice nucleation activity of Pseudomonas syringae inside of thunderstorms through numerical simulations using BRAMS (Brazilian Regional Atmospheric Model System. The numerical simulations were developed in order to investigate the effect on the total amount of rainwater as a function of ice nuclei (IN P. syringae concentrations with different scenarios (classified as S2 to S4 scenarios corresponding to a maximum of 102 to 104 IN bacteria per liter of cloud water plus the BRAMS default (classified as S5 scenario. Additionally, two other scenarios were included without any IN (S1 and the sum of RAMS default and S4 scenario (classified as S6. The chosen radiosonde data is for 3 March 2003, typical summertime in São Paulo City which presents a strong convective cell. The objective of the simulations was to analyze the effect of the IN concentrations on the BRAMS modeled cloud properties and precipitation. The simulated electrification of the cloud permitted analysis of the total flashes estimated from precipitable and non-precipitable ice mass fluxes in two different lightning frequencies. Among all scenarios, only S4 and S6 presented a tendency to decrease the total cloud water, and all bacteria scenarios presented a tendency to decrease the total amount of rain (−8%, corroborating other reports in the literature. All bacteria scenarios also present higher precipitable ice concentrations compared to S5 scenario, the RAMS default. The main results present the total flash number per simulation as well. From the results, the total flash numbers, from both lightning frequencies, in S4 and S6 scenarios

  14. Broad-band spectral studies of optical lightnings and possible correlation with solar activity

    International Nuclear Information System (INIS)

    Bhat, C.L.; Sapru, M.L.; Kaul, R.K.; Razdan, H.

    1984-01-01

    Optical pulses from lightning discharges have been recorded in a ground-based experiment, meant primarily for the detection of cosmic X- and γ-ray bursts through the atmospheric fluorescence technique. It is shown that the spectral ratio Asub(v)/Asub(y), i.e. the ratio of pulse amplitudes in the violet to that in yellow wavelength bands (3400-4300 A and 4400-6000 A respectively) provides a good indication of the lightning channel temperature, the range of derived temperatures extending from 5.000 K to 60.000 K. Based on the distribution of observed Asub(v)/Asub(y) values on a daily basis, it has been possible to separate the observed lightning activity into two classes. One class of event is shown to be correlated with the peaking of the global atmospheric electric field and occurs preferentially on days when the ground-level cosmic ray intensity shows a significant decrease in association with an increase in geomagnetic activity. The results are discussed in terms of the contemporary views regarding solar control of atmospheric electricity and the various sun-weather correlations reported earlier. (author)

  15. An Optical Lightning Simulator in an Electrified Cloud-Resolving Model to Prepare the Future Space Lightning Missions

    Science.gov (United States)

    Bovalo, Christophe; Defer, Eric; Pinty, Jean-Pierre

    2016-04-01

    The future decade will see the launch of several space missions designed to monitor the total lightning activity. Among these missions, the American (Geostationary Lightning Mapper - GLM) and European (Lightning Imager - LI) optical detectors will be onboard geostationary satellites (GOES-R and MTG, respectively). For the first time, the total lightning activity will be monitored over the full Earth disk and at a very high temporal resolution (2 and 1 ms, respectively). Missions like the French Tool for the Analysis of Radiation from lightNIng and Sprites (TARANIS) and ISS-LIS will bring complementary information in order to better understand the lightning physics and to improve the weather prediction (nowcasting and forecasting). Such missions will generate a huge volume of new and original observations for the scientific community and weather prediction centers that have to be prepared. Moreover, before the launch of these missions, fundamental questions regarding the interpretation of the optical signal property and its relation to cloud optical thickness and lightning discharge processes need to be further investigated. An innovative approach proposed here is to use the synergy existing in the French MesoNH Cloud-Resolving Model (CRM). Indeed, MesoNH is one of the only CRM able to simulate the lifecycle of electrical charges generated within clouds through non-inductive charging process (dependent of the 1-moment microphysical scheme). The lightning flash geometry is based on a fractal law while the electrical field is diagnosed thanks to the Gauss' law. The lightning optical simulator is linked to the electrical scheme as the lightning radiance at 777.4 nm is a function of the lightning current, approximated by the charges neutralized along the lightning path. Another important part is the scattering of this signal by the hydrometeors (mainly ice particles) that is taken into account. Simulations at 1-km resolution are done over the Langmuir Laboratory (New

  16. Verification of a Schumann Resonance Inversion Method for Global Lightning Activity in Absolute Units

    Science.gov (United States)

    Williams, E. R.; Guha, A.; Liu, Y.; Boldi, R. A.; Pracser, E.; Said, R.; Satori, G.; Bozoki, T.; Bor, J.; Atkinson, M.; Beggan, C.; Cummer, S.; Lyu, F.; Fain, B.; Hobara, Y.; Alexander, K.; Kulak, A.; McCraty, R.; Mlynarczyk, J.; Montanya, J.; Moore, R. C.; Neska, M.; Ortega, P.; Price, C. G.; Rawat, R.; Sato, M.; Sinha, A. K.; Yampolski, Y.

    2017-12-01

    The global reach of single, calibrated ELF receivers operating in the Schumann resonance (SR) band (3-50 Hz) has been verified by global maps of energetic Q-burst locations and vertical charge moment change, and by locations of independently verified transient luminous events in a wide variety of locations worldwide. It has also been previously shown that with as few as six ELF receivers in widely separated locations, multi-station, multi-modal SR parameters extracted from the SR "background" signal can be inverted to provide the centroid locations of continental lightning "chimneys" (Asia, Africa, Americas) and their respective lightning activities in absolute units (coul2 km2/sec). This inversion method involves a propagation model for the Earth-ionosphere cavity with day-night asymmetry. The Earth is now populated with more than 30 calibrated ELF receivers making continuous time series observations. This circumstance is exploited in the present study to verify the findings of the ELF inversion method. During the period May 17-20 and 23-24, 2015, two independent sets of nine ELF receivers each, in widely-separated geographical locations (first set: Antarctica (3 sites), Hungary, Japan (2 sites), Poland, Spitzbergen, and USA; second set: Antarctica, Canada, Cape Verde Island, Lithuania, New Zealand, Saudi Arabia, Scotland, Tahiti, and USA), are used to compare the locations and source strengths of lightning chimneys. Detailed comparisons will be shown over Universal Time for selected days.

  17. Nowcasting the lightning activity in Peninsular Malaysia using the GPS PWV during the 2009 inter-monsoons

    Directory of Open Access Journals (Sweden)

    Wayan Suparta

    2014-05-01

    Full Text Available The spatial and temporal radio wave delay of the Global Positioning System (GPS signal can be manipulated to estimate the precipitable water vapor (PWV which favorable for meteorological applications. A rapid change of the water vapor amount was a precondition for the unbalanced atmospheric charges, which noticeably associated with the development of convective cloud as a lightning chamber. According to this fact, GPS derived PWV will be utilized to nowcasting the lightning event for the next couple of hours. The variances of PWV of four-selected station of the Peninsular Malaysia during the past two inter-monsoons events in May and November 2009 were analyzed. To clarify the response, the changes of PWV in hourly Δ (max-min before the lightning event was investigated with minimum value 2 mm and is maintained at least three consecutive hours. There are 177 samples were extracted from this method and 69% of the sample showed the lightning occurrence with an average duration was after the six consecutive hours. The lightning day with 2 mm Δ was also higher than the fair weather of 6.3%. These findings suggest that the GPS data can be proposed further as a guide to nowcast the occurrence of lightning activity.

  18. A lightning climatology of the South-West Indian Ocean

    Directory of Open Access Journals (Sweden)

    C. Bovalo

    2012-08-01

    Full Text Available The World Wide Lightning Location Network (WWLLN data have been used to perform a lightning climatology in the South-West Indian Ocean (SWIO region from 2005 to 2011. Maxima of lightning activity were found in the Maritime Continent and southwest of Sri Lanka (>50 fl km−2 yr−1 but also over Madagascar and above the Great Lakes of East Africa (>10–20 fl km−2 yr−1. Lightning flashes within tropical storms and tropical cyclones represent 50 % to 100 % of the total lightning activity in some oceanic areas of the SWIO (between 10° S and 20° S.

    The SWIO is characterized by a wet season (November to April and a dry season (May to October. As one could expect, lightning activity is more intense during the wet season as the Inter Tropical Convergence Zone (ITCZ is present over all the basin. Flash density is higher over land in November–December–January with values reaching 3–4 fl km−2 yr−1 over Madagascar. During the dry season, lightning activity is quite rare between 10° S and 25° S. The Mascarene anticyclone has more influence on the SWIO resulting in shallower convection. Lightning activity is concentrated over ocean, east of South Africa and Madagascar.

    A statistical analysis has shown that El Niño–Southern Oscillation mainly modulates the lightning activity up to 56.8% in the SWIO. The Indian Ocean Dipole has a significant contribution since ~49% of the variability is explained by this forcing in some regions. The Madden–Julian Oscillation did not show significative impact on the lightning activity in our study.

  19. Lightning and Climate

    Science.gov (United States)

    Williams, E.

    2012-12-01

    Lightning is of interest in the domain of climate change for several reasons: (1) thunderstorms are extreme forms of moist convection, and lightning flash rate is a sensitive measure of that extremity, (2) thunderstorms are deep conduits for delivering water substance from the boundary layer to the upper troposphere and stratosphere, and (3) global lightning can be monitored continuously and inexpensively within a natural framework (the Earth-ionosphere waveguide and Schumann resonances). Lightning and temperature, and lightning and upper tropospheric water vapor, are positively correlated on weather-related time scales (diurnal, semiannual, and annual) with a lightning temperature sensitivity of order 10% per oC. Lightning also follows temperature variations on the ENSO time scale, both locally and globally. The response of lightning in some of its extreme forms (exceptional flash rates and the prevalence of sprite-producing mesoscale lightning, for example) to temperature variations will be addressed. Consistently obtained records of lightning activity on longer time scales are scarce as stable detection networks are uncommon. As a consequence, thunder day data have been used to extend the lightning record for climate studies, with evidence for increases over decades in urban areas. Global records of lightning following Schumann resonance intensity and from space-based optical sensors (OTD and LIS) are consistent with the record of ionospheric potential representing the global electrical circuit in showing flat behavior over the few decades. This flatness is not well understood, though the majority of all lightning flashes are found in the tropics, the most closely regulated portion of the atmosphere. Other analysis of frequency variations of Schumann resonances in recent decades shows increased lightning in the northern hemisphere, where the global warming is most pronounced. The quantity more fundamental than temperature for lightning control is cloud buoyancy

  20. Monitoring of lightning activity based on simultaneous measurement of electric field and electric field-change in the Tokyo metropolitan area

    Science.gov (United States)

    Yamashita, K.; Ohya, H.; Takahashi, Y.; Sato, M.

    2017-12-01

    Main objective of this study is nowcast of thunderstorm activity that causes extreme weather, such as torrential rain, based on lightning observation. Lightning observation has been focused on as an effective way for nowcast of thunderstorm activity. Spatial distribution of lightning discharge has been used as a proxy of the presence or absence of deep convection, which generates thunderstorm. We have constructed sensor network for lightning observation in the Tokyo metropolitan area, Japan, since 2013. In this network, VLF sensors (frequency range is 1 - 40 kHz) to measure electric field radiated from lightning discharges are distributed about 100 km apart. Additionally, slow antenna and electric field mill are also installed to detect electric field-change by lightning discharge. In this study, evaluations of not only spatial distribution but also scale distribution of lightning activity have been examined based on simultaneous measurement of electric field and electric field-change. As a scale of lightning discharge, charge moment change is derived. Preceding observation shows that there is extremely huge lightning whose scale is more than hundreds times bigger than that of averaged event. Estimation of scale for each lightning discharge would makes it possible to evaluate not only existence but also strength of atmospheric convection in thunderstorm area quantitatively. Based on lighting observation in the Tokyo metropolitan area, we start to construct new sensor network for real-time monitoring of lightning activity from this year. VLF sensors, slow antenna and electric field mill are mounted on real-time weather observation system named POTEKA developed by Meisei Electric Co., Ltd. and will be distributed in Metro Manila, Philippines under the 5-year project (SATREPS). At the presentation, observation in the Tokyo metropolitan area are summarized as a prototype for lightning observation that will be carried out in Metro Manila, Philippines.

  1. Characteristics of the structure change based on radar parameters and lightning activity on a big hailstorm case

    Science.gov (United States)

    Yi, Xiaoyuan; Zhang, Yijun; Sun, Xiaolei

    2017-04-01

    lightning activity was investigated, with the result that the radar parameters were able to describe properly the feature of merger process and the change of hailstorm structure change, and pulled ahead of the total lightning flash peak for 12min. The introduction of radar parameters were stated below: V40:the echo volume within the scope of 40dBZ reflects the size of the core of strong echo and its height, and it partly reflects the spatial size and intensity of the convective clouds set within the scope of research. upFV40(downFV40):the volume variability of the V40 above(under) -15? layer. ETS11:the sum of grids of the top which are above 11km of echo,not only reflects the development the thunderstorm' height, but also the size, and it is the parameter describing development of the thunderstorm system.

  2. Characteristics of cloud-to-ground lightning activity over Seoul, South Korea in relation to an urban effect

    Directory of Open Access Journals (Sweden)

    S. K. Kar

    2007-11-01

    Full Text Available Cloud-to-ground (CG lightning flash data collected by the lightning detection network installed at the Korean Meteorological Administration (KMA have been used to study the urban effect on lightning activity over and around Seoul, the largest metropolitan city of South Korea, for the period of 1989–1999. Negative and positive flash density and the percentage of positive flashes have been calculated. Calculation reveals that an enhancement of approximately 60% and 42% are observed, respectively, for negative and positive flash density over and downwind of the city. The percentage decrease of positive flashes occurs over and downwind of Seoul and the amount of decrease is nearly 20% compared to upwind values. The results are in good agreement with those obtained by Steiger et al. (2002 and Westcott (1995. CG lightning activities have also been considered in relation to annual averages of PM10 (particulate matter with an aerodynamic diameter smaller than 10 μm and sulphur dioxide (SO2 concentrations. Interesting results are found, indicating that the higher concentration of SO2 contributes to the enhancement of CG lightning flashes. On the other hand, the contribution from PM10 concentration has not appeared in this study to be as significant as SO2 in the enhancement of CG lightning flashes. Correlation coefficients of 0.33 and 0.64 are found between the change in CG lightning flashes and the PM10 and SO2, respectively, for upwind to downwind areas, suggesting a significant influence of the increased concentration of SO2 on the enhancement of CG flashes.

  3. Characteristics of cloud-to-ground lightning activity over Seoul, South Korea in relation to an urban effect

    Directory of Open Access Journals (Sweden)

    S. K. Kar

    2007-11-01

    Full Text Available Cloud-to-ground (CG lightning flash data collected by the lightning detection network installed at the Korean Meteorological Administration (KMA have been used to study the urban effect on lightning activity over and around Seoul, the largest metropolitan city of South Korea, for the period of 1989–1999. Negative and positive flash density and the percentage of positive flashes have been calculated. Calculation reveals that an enhancement of approximately 60% and 42% are observed, respectively, for negative and positive flash density over and downwind of the city. The percentage decrease of positive flashes occurs over and downwind of Seoul and the amount of decrease is nearly 20% compared to upwind values. The results are in good agreement with those obtained by Steiger et al. (2002 and Westcott (1995. CG lightning activities have also been considered in relation to annual averages of PM10 (particulate matter with an aerodynamic diameter smaller than 10 μm and sulphur dioxide (SO2 concentrations. Interesting results are found, indicating that the higher concentration of SO2 contributes to the enhancement of CG lightning flashes. On the other hand, the contribution from PM10 concentration has not appeared in this study to be as significant as SO2 in the enhancement of CG lightning flashes. Correlation coefficients of 0.33 and 0.64 are found between the change in CG lightning flashes and the PM10 and SO2, respectively, for upwind to downwind areas, suggesting a significant influence of the increased concentration of SO2 on the enhancement of CG flashes.

  4. Modulation of UK lightning by heliospheric magnetic field polarity

    Science.gov (United States)

    Owens, M. J.; Scott, C. J.; Lockwood, M.; Barnard, L.; Harrison, R. G.; Nicoll, K.; Watt, C.; Bennett, A. J.

    2014-11-01

    Observational studies have reported solar magnetic modulation of terrestrial lightning on a range of time scales, from days to decades. The proposed mechanism is two-step: lightning rates vary with galactic cosmic ray (GCR) flux incident on Earth, either via changes in atmospheric conductivity and/or direct triggering of lightning. GCR flux is, in turn, primarily controlled by the heliospheric magnetic field (HMF) intensity. Consequently, global changes in lightning rates are expected. This study instead considers HMF polarity, which doesn't greatly affect total GCR flux. Opposing HMF polarities are, however, associated with a 40-60% difference in observed UK lightning and thunder rates. As HMF polarity skews the terrestrial magnetosphere from its nominal position, this perturbs local ionospheric potential at high latitudes and local exposure to energetic charged particles from the magnetosphere. We speculate as to the mechanism(s) by which this may, in turn, redistribute the global location and/or intensity of thunderstorm activity.

  5. Lightning Injuries

    Science.gov (United States)

    ... to electrical equipment or telephone lines inside a house. Lightning can injure a person several ways: Lightning ... a feathering, branching pattern, consist of clusters of tiny pinpoint spots like a cigarette burn, or consist ...

  6. Using the VAHIRR Radar Algorithm to Investigate Lightning Cessation

    Science.gov (United States)

    Stano, Geoffrey T.; Schultz, Elise V.; Petersen, Walter A.

    2012-01-01

    Accurately determining the threat posed by lightning is a major area for improved operational forecasts. Most efforts have focused on the initiation of lightning within a storm, with far less effort spent investigating lightning cessation. Understanding both components, initiation and cessation, are vital to improving lightning safety. Few organizations actively forecast lightning onset or cessation. One such organization is the 45th Weather Squadron (45WS) for the Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS). The 45WS has identified that charged anvil clouds remain a major threat of continued lightning and can greatly extend the window of a potential lightning strike. Furthermore, no discernable trend of total lightning activity has been observed consistently for all storms. This highlights the need for more research to find a robust method of knowing when a storm will cease producing lightning. Previous lightning cessation work has primarily focused on forecasting the cessation of cloud-to -ground lightning only. A more recent, statistical study involved total lightning (both cloud-to-ground and intracloud). Each of these previous works has helped the 45WS take steps forward in creating improved and ultimately safer lightning cessation forecasts. Each study has either relied on radar data or recommended increased use of radar data to improve cessation forecasts. The reasoning is that radar data is able to either directly or by proxy infer more about dynamical environment leading to cloud electrification and eventually lightning cessation. The authors of this project are focusing on a two ]step approach to better incorporate radar data and total lightning to improve cessation forecasts. This project will utilize the Volume Averaged Height Integrated Radar Reflectivity (VAHIRR) algorithm originally developed during the Airborne Field Mill II (ABFM II) research project. During the project, the VAHIRR product showed a trend of increasing

  7. Birth of ball lightning

    Science.gov (United States)

    Lowke, J. J.; Smith, D.; Nelson, K. E.; Crompton, R. W.; Murphy, A. B.

    2012-10-01

    Many observations of ball lightning report a ball of light, about 10 cm in diameter, moving at about walking speed, lasting up to 20 s and frequently existing inside of houses and even aeroplanes. The present paper reports detailed observations of the initiation or birth of ball lightning. In two cases, navigation crew of aircraft saw ball lightning form at the windscreen inside the cockpit of their planes. In the first case, the ball lightning occurred during a thunderstorm, with much lightning activity outside of the plane. In the second case, large "horns" of electrical corona were seen outside of the plane at the surface of the radome, just prior to the formation of the ball lightning. A third case reports ball lightning formed inside of a house, during a thunderstorm, at a closed glass window. It is proposed, based on two-dimensional calculations of electron and ion transport, that ball lightning in these cases is driven and formed by atmospheric ions impinging and collecting on the insulating surface of the glass or Perspex windows. This surface charge can produce electric fields inside of the cockpit or room sufficient to sustain an electric discharge. Charges of opposite sign to those outside of the window accumulate on the inside surface of the glass, leaving a ball of net charge moving inside of the cockpit or room to produce a pulsed discharge on a microsecond time scale.

  8. About the variations on lightning activity in Brazil from 1960s to 1990s based on thunderstorm days: preliminary results

    Science.gov (United States)

    Pinto, O.; Pinto, I. R.

    2009-12-01

    Thunder day frequencies (TD) have been collected throughout the world in a systematic way since the beginning of the twenty century, producing the longest lightning-related data set available to investigate possible climatic changes in the global, tropical or, even, regional lightning activity. Such changes may be related to natural climate variations associated with many different large scale phenomena and/or to anthropogenic warming variations. The role of each component may be different at different spatial scales. In Brazil TD data have been recorded in many stations throughout the country. In this report, TD data from 1960s to 1990s in different stations in Brazil are analyzed looking for variations related to volcanic eruptions, El Niño Southern Oscillation (ENSO), tropical Atlantic sea-surface temperature (SST) anomaly, Pacific Decadal Oscillation (POD), solar irradiance and urban effects. The preliminary results are discussed in the context of their implications for future climatic changes in the lightning activity.

  9. The lightning climatology of South Africa

    Directory of Open Access Journals (Sweden)

    Morné Gijben

    2012-03-01

    Full Text Available In 2005, the South African Weather Service installed a state-of-the-art cloud-to-ground lightning detection network across the country. The data recorded by this network in 2006 was utilised in the development of an initial lightning climatology of South Africa. Until 2010, this climatology was based on data from a single year. This paper updates this climatology with the lightning data for the 2006–2010 period, which is the first actual lightning climatology by the South African Weather Service based on data covering 5 years. A number of different maps were created from these lightning data. These were lightning ground flash density, median peak kiloampere, percentage positive and average flash multiplicity maps. These four maps were in turn used to develop lightning intensity risk, positive lightning risk and total lightning risk maps. Analysis of the maps showed that the highest concentrations of lightning are found over the central to northern interior of the country, with areas along the northern parts of the eastern escarpment experiencing the highest flash densities and falling within the extreme risk category. Both the positive and total lightning risks are severe for almost the entire country. Only towards the west of the country does the lightning risk decrease. This lightning climatology can now be used throughout South Africa for various disciplines. It will be especially useful for setting lightning safety standards and identifying priority areas for installing lightning conductors and conducting public awareness campaigns.

  10. NOx production by lightning in Hector: first airborne measurements during SCOUT-O3/ACTIVE

    Directory of Open Access Journals (Sweden)

    D. Brunner

    2009-11-01

    Full Text Available During the SCOUT-O3/ACTIVE field phase in November–December 2005, airborne in situ measurements were performed inside and in the vicinity of thunderstorms over northern Australia with several research aircraft (German Falcon, Russian M55 Geophysica, and British Dornier-228. Here a case study from 19 November is presented in detail on the basis of airborne trace gas measurements (NO, NOy, CO, O3 and stroke measurements from the German LIghtning Location NETwork (LINET, set up in the vicinity of Darwin during the field campaign. The anvil outflow from three different types of thunderstorms was probed by the Falcon aircraft: (1 a continental thunderstorm developing in a tropical airmass near Darwin, (2 a mesoscale convective system (MCS, known as Hector, developing within the tropical maritime continent (Tiwi Islands, and (3 a continental thunderstorm developing in a subtropical airmass ~200 km south of Darwin. For the first time detailed measurements of NO were performed in the Hector outflow. The highest NO mixing ratios were observed in Hector with peaks up to 7 nmol mol−1 in the main anvil outflow at ~11.5–12.5 km altitude. The mean NOx (=NO+NO2 mixing ratios during these penetrations (~100 km width varied between 2.2 and 2.5 nmol mol−1. The NOx contribution from the boundary layer (BL, transported upward with the convection, to total anvil-NOx was found to be minor (x (LNOx in the well-developed Hector system was estimated to 0.6–0.7 kg(N s−1. The highest average stroke rate of the probed thunderstorms was observed in the Hector system with 0.2 strokes s−1 (here only strokes with peak currents ≥10 kA contributing to LNOx were considered. The LNOx mass flux and the stroke rate were combined to estimate the LNOx production rate in the different thunderstorm types. For a better comparison with other studies, LINET strokes were scaled with Lightning Imaging Sensor (LIS flashes. The LNOx production rate per LIS flash was estimated

  11. Lightning Activity Relative to the Microphysical and Kinematic Structure of Storms during a Thunder-Snow Episode on 29-30 November 2006

    Science.gov (United States)

    Emersic, C.; Macgorman, D.; Schuur, T.; Lund, N.; Payne, C.; Bruning, E.

    2007-12-01

    We have examined lightning activity relative to the microphysical and kinematic structure of a winter thunderstorm complex (a thunder-snow episode) observed east of Norman, Oklahoma during the evening of 29-30 November 2006. Polarimetric radar provided information about the type of particles present in various regions of the storms. The Lightning Mapping Array (LMA) recorded VHF signals produced by developing lightning channels. The times of arrival of these lightning signals across the array were then used to reconstruct the location and structure of lightning, and these reconstructions were overlaid with radar data to examine the relationship between lightning properties and storm particle types. Four storms in this winter complex have been examined. It was inferred from lightning structure that, in their mature stage, all cells we examined had a positive tripole electrical structure (an upper positive charge center, a midlevel negative charge center, and a lower positive charge center). The storms began with lightning activity in the lower dipole (lower positive and midlevel negative regions), but this evolved into lightning activity throughout the tripole structure within approximately 15-20 minutes. In the longer lived storms, the mature stage lasted for approximately 1.5-2 hours. During this stage, the lower positive charge region was situated less than 5 km above ground, the midlevel negative charge region was typically above 5 km, and the upper positive charge region was located at an altitude of less than 10 km in all the storm cells analyzed. The charge regions descended over approximately the last 30 minutes of lightning activity, the lower charge regions eventually reaching ground. This resulted in the loss of the lower positive charge center and the subsequent diminishment of the lower negative charge center. Lightning initiation usually coincided with the edges of regions of high reflectivity and was coincident with the presence of graupel and ice

  12. Measurement of electromagnetic waves in ELF and VLF bands to monitor lightning activity in the Maritime Continent

    Science.gov (United States)

    Yamashita, Kozo; Takahashi, Yukihiro; Ohya, Hiroyo; Tsuchiya, Fuminori; Sato, Mitsuteru; Matsumoto, Jun

    2013-04-01

    Data of lightning discharge has been focused on as an effective way for monitoring and nowcasting of thunderstorm activity which causes extreme weather. Spatial distribution of lightning discharge has been used as a proxy of the presence or absence of deep convection. Latest observation shows that there is extremely huge lightning whose scale is more than hundreds times bigger than that of averaged event. This result indicates that lightning observation should be carried out to estimate not only existence but also scale for quantitative evaluation of atmospheric convection. In this study, lightning observation network in the Maritime Continent is introduced. This network is consisted of the sensors which make possible to measure electromagnetic wave radiated from lightning discharges. Observation frequency is 0.1 - 40 kHz for the measurement of magnetic field and 1 - 40 kHz for that of electric field. Sampling frequency is 100 kHz. Waveform of electromagnetic wave is recorded by personal computer. We have already constructed observation stations at Tainan in Taiwan (23.1N, 121.1E), Saraburi in Thailand (14.5N, 101.0E), and Pontianak in Indonesia (0.0N, 109.4E). Furthermore, we plan to install the monitoring system at Los Banos in Philippines (14.18, 121.25E) and Hanoi in Viet Nam. Data obtained by multipoint observation is synchronized by GPS receiver installed at each station. By using data obtained by this network, location and scale of lightning discharge can be estimated. Location of lightning is determined based on time of arrival method. Accuracy of geolocation could be less than 10km. Furthermore, charge moment is evaluated as a scale of each lightning discharge. It is calculated from electromagnetic waveform in ELF range (3-30 kHz). At the presentation, we will show the initial result about geolocation for source of electromagnetic wave and derivation of charge moment value based on the measurement of ELF and VLF sferics.

  13. On the sensitivity of cloud-to-ground lightning activity to surface air temperature changes at different timescales in São Paulo, Brazil

    Science.gov (United States)

    Pinto, O.; Pinto, I. R. C. A.

    2008-10-01

    This paper presents a study about the sensitivity of cloud-to-ground (CG) lightning activity to changes in surface air temperature at daily, monthly, yearly, and decadal timescales in the city of São Paulo (Brazil). Lightning data collected in the city by the Brazilian Lightning Detection Network (BrasilDat) from 1999 to 2006 and thunderstorm day data obtained from 1951 to 2006 were analyzed and compared with surface air temperature data. The lightning activity increases significantly with increasing temperature, with a sensitivity of approximately 40% per 1°C for daily and monthly timescales and approximately 30% per 1°C for decadal timescale. For the yearly timescale, the increase is not statistically significant. The lower sensitivity for the decadal timescale suggests that the lightning sensitivity to changes in surface air temperature decreases for larger timescales, in agreement with what is expected on the basis of convective adjustment. The decadal lightning sensitivity found in this study is in reasonable agreement with the increase in the global lightning activity estimated by most climate models. The study is the first to investigate in detail this relationship in a large urban area inside the tropics and should contribute to the effort to understand the impact of the global warming on lightning activity.

  14. Solar wind modulation of UK lightning

    Science.gov (United States)

    Davis, Chris; Harrison, Giles; Lockwood, Mike; Owens, Mathew; Barnard, Luke

    2013-04-01

    The response of lightning rates in the UK to arrival of high speed solar wind streams at Earth is investigated using a superposed epoch analysis. The fast solar wind streams' arrivals are determined from modulation of the solar wind Vy component, measured by the Advanced Composition Explorer (ACE) spacecraft. Lightning rate changes around these event times are then determined from the very low frequency Arrival Time Difference (ATD) system of the UK Met Office. Arrival of high speed streams at Earth is found to be preceded by a decrease in total solar irradiance and an increase in sunspot number and Mg II emissions. These are consistent with the high speed stream's source being co-located with an active region appearing on the Eastern solar limb and rotating at the 27 day rate of the Sun. Arrival of the high speed stream at Earth also coincides with a rapid decrease in cosmic ray flux and an increase in lightning rates over the UK, persisting for around 40 days. The lightning rate increase is corroborated by an increase in the total number of thunder days observed by UK Met stations, again for around 40 days after the arrival of a high speed solar wind stream. This increase in lightning may be beneficial to medium range forecasting of hazardous weather.

  15. Ball lightning.

    OpenAIRE

    Stenhoff, Mark

    1988-01-01

    Ball lightning is alleged by some to be a rare atmospheric phenomenon usually associated with thunderstorms, while others hold that it does not exist. This controversy has continued for centuries. This study comprises a critical evaluation of evidence for the existence of ball lightning. An historical review of the controversy is first presented, giving a chronological account of developments in ball lightning theories and of important observations alleged to be of the phenomenon. Other pheno...

  16. Lightning Technology.

    Science.gov (United States)

    1980-04-01

    thunder . The thunder signals were recorded on a second FM magnetic tape channel. In this manner, the time of occurrence, the nature of the lightning ...from the Kiva to the lightning cur- rent element of interest is based on the assumption that the time from flash to thunder multiplied by the speed of...some corona-like discharges before the main lightning event. The acoustically determined (per section 4) thunder sources are displayed in figure 5.4

  17. Lightning activity, rainfall and flash flooding – occasional or interrelated events? A case study in the island of Crete

    Directory of Open Access Journals (Sweden)

    A. G. Koutroulis

    2012-04-01

    Full Text Available The majority of cyclones passing over Crete in late autumn to early winter originate from southwest, west and northwest and are of varying size and intensity. A number of these cyclones cause flash floods. The present study reports the possible relationships between lighting activity and high precipitation related to flash flood events. In this study an attempt was made to correlate the lightning number and location, recorded by the ZEUS lightning detection system, with the rainfall characteristics for sixteen rain events (4 flood and 12 non-flood events on the island of Crete, during the period 2008–2009. Spatiotemporal analysis of rain and rain rate with flash count was performed with respect to distance (radius of flashes from raingauge location at various temporal scales, in order to examine the correlation of accumulated rainfall and lightning activity. The maximum attained statistical significant correlation was obtained within a circular area of an average radius of 15 km around the raingauge, and an average time lag of flash count prior precipitation accumulation of 15 min. The maximum correlation between the lightning and rainfall data is obtained for shorter time lags for the flood events (15 min than the non-flood events (25 min, that could reflect the faster propagation of flood triggering storms due to high convective activity. Results show increased lightning activity occurring during flood triggering storms, by an average of four times higher. Furthermore, there is evidence that the number of flashes that occur during a precipitation event is related to precipitation depth when the latter is adequate to produce a flood event. Differences between flood and non-flood producing storms need to be further assessed by analyzing more independent parameters, including the synoptic conditions and dominant flash flood hydrological generating processes.

  18. Ball lightning burn.

    Science.gov (United States)

    Selvaggi, Gennaro; Monstrey, Stan; von Heimburg, Dennis; Hamdi, Mustapha; Van Landuyt, Koen; Blondeel, Phillip

    2003-05-01

    Ball lightning is a rare physical phenomenon, which is not yet completely explained. It is similar to lightning but with different, peculiar characteristics. It can be considered a mix of fire and electricity, concentrated in a fireball with a diameter of 20-cm that most commonly appears suddenly, even in indoor conditions, during a thunderstorm. It moves quickly for several meters, can change direction, and ultimately disappears. During a great storm, a 28-year-old man and his 5-year-old daughter sustained burn wounds after ball lightning came from the outdoors through a chimney. These two patients demonstrated signs of fire and electrical injuries. The father, who lost consciousness, sustained superficial second-degree burn wounds bilaterally on the zygomatic area and deep second-degree burn wounds on his right hand (total body surface area, 4%). His daughter demonstrated superficial second-degree burn wounds on the left part of the face and deep second-degree and third-degree burn wounds (total body surface area, 30%) on the left neck, both upper arms, and the back. In this article, the authors report the first two cases of burn injuries resulting from ball lightning contact indoors. The literature on this rare phenomenon is reviewed to elucidate the nature of ball lightning. Emphasis is placed on the nature of injuries after ball lightning contact, the therapy used, and the long-term complications.

  19. Simultaneous Observation of Lightning and Terrestrial Gamma-ray Flashes

    Science.gov (United States)

    Alnussirat, S.; Christian, H. J., Jr.; Fishman, G. J.; Burchfield, J. C.

    2017-12-01

    The relative timing between TGFs and lightning optical emissions is a critical parameter that may elucidate the production mechanism(s) of TGFs. In this work, we study the correlation between optical emissions detected by the Geostationary Lightning Mapper (GLM) and TGFs triggered by the Fermi-GBM. The GLM is the only instrument that detects total lightning activities (IC and CG) continuously (day and night) over a large area of the Earth, with very high efficiency and location accuracy. The unique optical emission data from the GLM will enable us to study, for the first time, the lightning activity before and after the TGF production. From this investigation, we hope to clarify the production mechanism of TGFs and the characteristics of thundercloud cells that produce them. A description of the GLM concept and operation will be presented and as well as the preliminary results of the TGF-optical emission correlation.

  20. New results about the study of the lightning activity and characteristics over the large urban area of the city of São Paulo

    Science.gov (United States)

    Farias, W. R.; Pinto, O.; Pinto, I. R.

    2009-12-01

    The urban effect on lightning activity has been studied in many places around the world. The Metropolitan Region of São Paulo (MRSP) in the Southeast region of Brazil is one of the greatest and more populous urban areas of the world with a density of about 3000 inhabitants/km2. Similar to observations in other large urban areas, there is a significant enhancement in the number of negative cloud-to-ground (CG) lightning and a decrease in the percentage of positive CG flashes over the city of São Paulo. This work investigates the role of air polluted on lightning in MRSP. The CG lightning data set used was provided by Brazilian lightning detection network (BrasilDAT) for a period of 10 years (1999 - 2008). In this period, only days with CG flashes during the spring and summer seasons (from October to March) were considered and, for these days, only lightning data from 14 h to 20 h LT, were considered since this period corresponds to the time of the day with maximum lightning activity. The air polluted data set used in this work, was provided by the São Paulo environmental agencies (CETESB). The main results are: there is a tendency of increase in the ratio between lightning activity in the center area and surrounding area of the MRSP during the ten years in agreement with the same tendency observed for the number of automotive vehicles circulating on the center area of the city; there is a statistical significant increase in the CG lightning activity during the week days over MRSP related to the PM10 concentration. Apparently the increase in the lightning activity is related to an increase in the lifetime of the storms and, in consequence, the number of flashes per storm, and not to the mean flash rate of the storms. However, the increase also suggest that the effect of the pollution in the enhancement of the CG lightning activity is probably less significant compared to the effect of the urban heat island. A similar study is being done for other lightning spot

  1. Ball lightning risk to aircraft

    Science.gov (United States)

    Doe, R.; Keul, A.

    2009-04-01

    Lightning is a rare but regular phenomenon for air traffic. Aircraft are designed to withstand lightning strikes. Research on lightning and aircraft can be called detailed and effective. In the last 57 years, 18 reported lightning aviation disasters with a fatality figure of at least 714 persons occurred. For comparison, the last JACDEC ten-year average fatality figure was 857. The majority encountered lightning in the climb, descent, approach and/or landing phase. Ball lightning, a metastable, rare lightning type, is also seen from and even within aircraft, but former research only reported individual incidents and did not generate a more detailed picture to ascertain whether it constitutes a significant threat to passenger and aircraft safety. Lacking established incident report channels, observations were often only passed on as "air-travel lore". In an effort to change this unsatisfactory condition, the authors have collected a first international dataset of 38 documented ball lightning aircraft incidents from 1938 to 2001 involving 13 reports over Europe, 13 over USA/Canada, and 7 over Russia. 18 (47%) reported ball lightning outside the aircraft, 18 (47%) inside, 2 cases lacked data. 8 objects caused minor damage, 8 major damage (total: 42%), only one a crash. No damage was reported in 18 cases. 3 objects caused minor crew injury. In most cases, ball lightning lasted several seconds. 11 (29%) incidents ended with an explosion of the object. A cloud-aircraft lightning flash was seen in only 9 cases (24%) of the data set. From the detailed accounts of air personnel in the last 70 years, it is evident that ball lightning is rarely, but consistently observed in connection with aircraft and can also occur inside the airframe. Reports often came from multiple professional witnesses and in several cases, damages were investigated by civil or military authorities. Although ball lightning is no main air traffic risk, the authors suggest that incident and accident

  2. Comparison of Lightning Activity and Radar-Retrieved Microphysical Properties in EULINOX Storms

    OpenAIRE

    Fehr, T.; Dotzek, N.; Höller, H.

    2005-01-01

    A combined analysis of microphysical thunderstorm properties derived by C-band polarimetric Doppler radar measurements and lightning observations from two ground-based systems are presented. Three types of storms, a multicell, a supercell, and a squall line, that were observed during the European Lightning Nitrogen Oxides project (EULINOX) are investigated. Correlations are sought between the mass of rain, graupel, hail, and snow derived form radar observations at different height levels and ...

  3. Nowcast of thunderstorm and typhoon activity based on lightning detection and flexible operation of micro-satellites

    Science.gov (United States)

    Takahashi, Y.

    2016-12-01

    It has become known that lightning activity represents the thunderstorm activity, namely, the intensity and area of precipitation and/or updraft. Thunderstorm is also important as a proxy of the energy input from ocean to atmosphere in typhoon, meaning that if we could monitor the thunderstorm with lightning we could predict the maximum wind velocity near the typhoon center by one or two days before. Constructing ELF and VLF radio wave observation network in Southeast Asia (AVON) and a regional dense network of automated weather station in a big city, we plan to establish the monitoring system for thunderstorm development in western pacific warm pool (WPWP) where typhoon is formed and in detail in big city area. On the other hand, some developing countries in SE-Asia are going to own micro-satellites dedicated to meteorological remote sensing. Making use of the lightning activity data measured by the ground-based networks, and information on 3-D structures of thunderclouds observed by the flexible on-demand operation of the remote-sensing micro-satellites, we would establish a new methodology to obtain very detail semi-real time information that cannot be achieved only with existing observation facilities, such as meteorological radar or large meteorological satellite. Using this new system we try to issue nowcast for the local thunderstorm and for typhoons. The first attempt will be carried out in Metro Manila in Philippines and WPWP as one of the SATREPS projects.

  4. Lightning Injuries

    Science.gov (United States)

    ... News) Small Study Uncovers Brain Disease in Former Soccer Players (Video) Anterior Cruciate Ligament (Video) Resisted Finger Abduction and Extension With Putty Additional Content Medical News Lightning Injuries By Daniel P. Runde, MD, MME, Assistant Clinical ...

  5. Lightning Protection

    Science.gov (United States)

    1994-01-01

    Kit-built airplanes are more affordable because they are assembled by the owner and do not require Federal Aviation Administration (FAA) certification. The Glasair III, is an advanced technology homebuilt, constructed of a fiberglass and graphite fiber composite material, and equipped with digital instruments. Both technologies make the airplane more susceptible to lightning effects. When Glasair manufacturer, Stoddard-Hamilton, decided that lightning protection would enable more extensive instrument flight and make the plane more marketable, they proposed a joint development program to NASA Langley Research Center (LAR). Under a Small Business Innovation Research (SBIR) contract, Langley contractors designed and tested a lightning protection system, and the Glasair III-LP became the first kit-built composite aircraft to be lightning tested and protection-verified under FAA guidelines for general aviation aircraft.

  6. Lightning strikes

    International Nuclear Information System (INIS)

    Dance, B.

    1982-01-01

    If a nuclear weapon were struck by a powerful lightning flash, what would happen Scientists have assembled a simulator to produce exceptionally powerful discharges to try to find the answer to this question by practical test. The Sandia facility enables the extremely powerful lightning discharges which occur only once in every hundred lightning strokes to be duplicated. A bolt is composed of a series of strokes between two clouds or between one cloud and the earth. The simulator consists of four circuits, an inductor, a resistor and a special crowbar-switch developed at Sandia. The crowbar is for accuracy in the simulation of a lightning stroke. The test data is conveyed to computers for analysis by means of fibre-optic links. The first series of tests involve the warhead for the Air-Launched Cruise Missile

  7. Evidence for solar wind modulation of lightning

    Science.gov (United States)

    Scott, C. J.; Harrison, R. G.; Owens, M. J.; Lockwood, M.; Barnard, L.

    2014-05-01

    The response of lightning rates over Europe to arrival of high speed solar wind streams at Earth is investigated using a superposed epoch analysis. Fast solar wind stream arrival is determined from modulation of the solar wind V y component, measured by the Advanced Composition Explorer spacecraft. Lightning rate changes around these event times are determined from the very low frequency arrival time difference (ATD) system of the UK Met Office. Arrival of high speed streams at Earth is found to be preceded by a decrease in total solar irradiance and an increase in sunspot number and Mg II emissions. These are consistent with the high speed stream’s source being co-located with an active region appearing on the Eastern solar limb and rotating at the 27 d period of the Sun. Arrival of the high speed stream at Earth also coincides with a small (˜1%) but rapid decrease in galactic cosmic ray flux, a moderate (˜6%) increase in lower energy solar energetic protons (SEPs), and a substantial, statistically significant increase in lightning rates. These changes persist for around 40 d in all three quantities. The lightning rate increase is corroborated by an increase in the total number of thunder days observed by UK Met stations, again persisting for around 40 d after the arrival of a high speed solar wind stream. This result appears to contradict earlier studies that found an anti-correlation between sunspot number and thunder days over solar cycle timescales. The increase in lightning rates and thunder days that we observe coincides with an increased flux of SEPs which, while not being detected at ground level, nevertheless penetrate the atmosphere to tropospheric altitudes. This effect could be further amplified by an increase in mean lightning stroke intensity that brings more strokes above the detection threshold of the ATD system. In order to remove any potential seasonal bias the analysis was repeated for daily solar wind triggers occurring during the summer

  8. Lightning incidents in Mongolia

    Directory of Open Access Journals (Sweden)

    Myagmar Doljinsuren

    2015-11-01

    Full Text Available This is one of the first studies that has been conducted in Mongolia on the distribution of lightning incidents. The study covers a 10-year period from 2004 to 2013. The country records a human death rate of 15.4 deaths per 10 million people per year, which is much higher than that of many countries with similar isokeraunic level. The reason may be the low-grown vegetation observed in most rural areas of Mongolia, a surface topography, typical to steppe climate. We suggest modifications to Gomes–Kadir equation for such countries, as it predicts a much lower annual death rate for Mongolia. The lightning incidents spread over the period from May to August with the peak of the number of incidents occurring in July. The worst lightning affected region in the country is the central part. Compared with impacts of other convective disasters such as squalls, thunderstorms and hail, lightning stands as the second highest in the number of incidents, human deaths and animal deaths. Economic losses due to lightning is only about 1% of the total losses due to the four extreme weather phenomena. However, unless precautionary measures are not promoted among the public, this figure of losses may significantly increase with time as the country is undergoing rapid industrialization at present.

  9. Lightning Forecasts and Data Assimilation into Numerical Weather Prediction Models

    Science.gov (United States)

    MacGorman, D. R.; Mansell, E. R.; Fierro, A.; Ziegler, C.

    2012-12-01

    coverage even farther into remote regions and provides the most promising means for routine thunderstorm detection over oceans. On-going research is continually expanding the methods used to assimilate lightning data, which began with simple techniques for assimilating CG data and now are being extended to assimilate total lightning data. Most approaches either have used the lightning data simply to indicate where the subgrid scale convective parameterization of a model should produce deep convection or have used the lightning data to indicate how to modify a model variable related to thunderstorms, such as rainfall rate or water vapor mixing ratio. The developing methods for explicitly predicting lightning activity provide another, more direct means for assimilating total lightning data, besides providing information valuable to the general public and to many governmental and commercial enterprises. Such a direct approach could be particularly useful for ensemble techniques used to produce probabilistic thunderstorm forecasts.

  10. Modulation of UK lightning and the atmospheric electric circuit by heliospheric magnetic field polarity

    Science.gov (United States)

    Owens, Mathew; Scott, Chris; Lockwood, Mike; Barnard, Luke; Harrison, Giles; Nicoll, Keri; Watt, Clare; Bennett, Alec

    2015-04-01

    Observational studies have reported solar magnetic modulation of terrestrial lightning on a range of time scales, from days to decades. The proposed mechanism is two-step: lightning rates vary with galactic cosmic ray (GCR) flux incident on Earth, either via changes in atmospheric conductivity and/or direct triggering of lightning. GCR flux is, in turn, primarily controlled by the heliospheric magnetic field (HMF) intensity. Consequently, global changes in lightning rates are expected. This study instead considers HMF polarity, which doesn't greatly affect total GCR flux. Opposing HMF polarities are, however, associated with a 40 to 60% difference in observed UK lightning and thunder rates. As HMF polarity skews the terrestrial magnetosphere from its nominal position, this perturbs local ionospheric potential at high latitudes and local exposure to energetic charged particles from the magnetosphere. We speculate as to the mechanism(s) by which this may, in turn, redistribute the global location and/or intensity of thunderstorm activity.

  11. Lightning Imaging Sensor (LIS) on the International Space Station (ISS): Launch, Installation, Activation and First Results

    Science.gov (United States)

    Blakeslee, R. J.; Christian, H. J.; Mach, D. M.; Buechler, D. E.; Wharton, N. A.; Stewart, M. F.; Ellett, W. T.; Koshak, W. J.; Walker, T. D.; Virts, K.; hide

    2017-01-01

    Mission: Fly a flight-spare LIS (Lightning Imaging Sensor) on ISS to take advantage of unique capabilities provided by the ISS (e.g., high inclination, real time data); Integrate LIS as a hosted payload on the DoD Space Test Program-Houston 5 (STP-H5) mission and launch on a Space X rocket for a minimum 2 year mission. Measurement: NASA and its partners developed and demonstrated effectiveness and value of using space-based lightning observations as a remote sensing tool; LIS measures lightning (amount, rate, radiant energy) with storm scale resolution, millisecond timing, and high detection efficiency, with no land-ocean bias. Benefit: LIS on ISS will extend TRMM (Tropical Rainfall Measuring Mission) time series observations, expand latitudinal coverage, provide real time data to operational users, and enable cross-sensor calibration.

  12. Inversion of Multi-Station Schumann Resonance Background Records for Global Lightning Activity in Absolute Units

    Science.gov (United States)

    Williams, E. R.; Mushtak, V. C.; Guha, A.; Boldi, R. A.; Bor, J.; Nagy, T.; Satori, G.; Sinha, A. K.; Rawat, R.; Hobara, Y.; Sato, M.; Takahashi, Y.; Price, C. G.; Neska, M.; Alexander, K.; Yampolski, Y.; Moore, R. C.; Mitchell, M. F.; Fraser-Smith, A. C.

    2014-12-01

    Every lightning flash contributes energy to the TEM mode of the natural global waveguide that contains the Earth's Schumann resonances. The modest attenuation at ELF (0.1 dB/Mm) allows for the continuous monitoring of the global lightning with a small number of receiving stations worldwide. In this study, nine ELF receiving sites (in Antarctica (3 sites), Hungary, India, Japan, Poland, Spitsbergen and USA) are used to provide power spectra at 12-minute intervals in two absolutely calibrated magnetic fields and occasionally, one electric field, with up to five resonance modes each. The observables are the extracted modal parameters (peak intensity, peak frequency and Q-factor) for each spectrum. The unknown quantities are the geographical locations of three continental lightning 'chimneys' and their lightning source strengths in absolute units (C2 km2/sec). The unknowns are calculated from the observables by the iterative inversion of an evolving 'sensitivity matrix' whose elements are the partial derivatives of each observable for all receiving sites with respect to each unknown quantity. The propagation model includes the important day-night asymmetry of the natural waveguide. To overcome the problem of multiple minima (common in inversion problems of this kind), location information from the World Wide Lightning Location Network has been used to make initial guess solutions based on centroids of stroke locations in each chimney. Results for five consecutive days in 2009 (Jan 7-11) show UT variations with the African chimney dominating on four of five days, and America dominating on the fifth day. The amplitude variations in absolute source strength exceed that of the 'Carnegie curve' of the DC global circuit by roughly twofold. Day-to-day variations in chimney source strength are of the order of tens of percent. Examination of forward calculations performed with the global inversion solution often show good agreement with the observed diurnal variations at

  13. A study of lightning activity over land and oceanic regions of India

    Indian Academy of Sciences (India)

    Otherwise, in the absence of a flash, in fair weather condition, it is nearly impossible to know that the earth's ...... representing different climate regimes. Annual mean lightning flash count and no. of stations on which these means are based. Normalized value. Flash. Standard. No. of of flash count, i.e.,. Climate regime count.

  14. Effect of urbanization on lightning over four metropolitan cities of India

    Science.gov (United States)

    Lal, D. M.; Pawar, S. D.

    2011-01-01

    In the recent years the effect of urbanization on local convections and lightning has been studied very extensively. Here we have analyzed the last 8 years (from 2001 to 2008) data of total lightning, Aerosol Optical Depth (AOD) and rainfall over two inland and two coastal metropolitan cities of India, to study the effect of urbanization on lightning. The lightning and rainfall data are taken from TRMM satellite and AOD data is taken from Moderate Resolution Imaging Spectroradiometer (MODIS) aboard the Terra (EOS AM) and Aqua (EOS PM) satellites. Our analysis shows that both the inland cities show considerable enhancement, where as both the coastal cities do not show enhancement in lightning, in the last 8 years. The results show that, over a inland city, where aerosol concentration is not increased appreciably in last few years the enhancement in convective activity and lightning is controlled by thermodynamic effect, where as, where aerosol concentration show increasing trend, aerosols play major roll in enhancement in lightning activity. It has been also found that over a city where aerosol concentration show increasing trend, lightning show a sharp increase due to combined positive effect of thermodynamics and aerosols, however rainfall show only small increase because of negative effect of aerosols on rainfall. The analysis of lightning, aerosols and rainfall over coastal cities do not show any increasing trend in rainfall and lightning activity which suggest that during premonsoon period all these parameters are controlled by large scale processes and therefore heat island effect or aerosol effect are not observed in both the coastal cities.

  15. Lightning Bugs

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 7; Issue 9. Lightning Bugs. B Gajendra Babu M Kannan. General Article Volume 7 Issue 9 September 2002 pp 49-55. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/007/09/0049-0055. Keywords.

  16. Processes for the administration give the radio-active lightning rod in Brazil

    International Nuclear Information System (INIS)

    Torres de Miranda, L.E.; Vicente, R.

    1998-01-01

    Radioactive lightning rods were manufactured in Brazil until 1989, when the national nuclear authority lifted the licenses to using radioactive sources in this consumer product. Since then, the installed devices are being replaced by Franklin type rods and being collected for treatment as radioactive waste. In this report we present options for the treatment of this radioactive waste. The conclusions may serve as input to the process of decision on the overall management strategic to be adopted by the authorities

  17. TOTAL 2003 activities report in brief

    International Nuclear Information System (INIS)

    2004-01-01

    This activities report presents the activities of the petroleum industry Group Total for the year 2003. The following topics are detailed: the corporate social responsibility with the environment stewardship, the energy future management, the safety enhancing, the human resources and the ethics and local development; the shareholder information with the Total share and the share-holding structure; the activities with informations on the Group, the main events, the upstream exploration and production,, the downstream refining, marketing, trading and shipping, the chemicals with overview 2003, base chemical and polymers, performance and specialities. (A.L.B.)

  18. Lightning NOx Estimates from Space-Based Lightning Imagers

    Science.gov (United States)

    Koshak, William J.

    2017-01-01

    The intense heating of air by a lightning channel, and subsequent rapid cooling, leads to the production of lightning nitrogen oxides (NOx = NO + NO2) as discussed in Chameides [1979]. In turn, the lightning nitrogen oxides (or "LNOx" for brevity) indirectly influences the Earth's climate because the LNOx molecules are important in controlling the concentration of ozone (O3) and hydroxyl radicals (OH) in the atmosphere. Climate is most sensitive to O3 in the upper troposphere, and LNOx is the most important source of NOx in the upper troposphere at tropical and subtropical latitudes; hence, lightning is a useful parameter to monitor for climate assessments. The National Climate Assessment (NCA) program was created in response to the Congressionally-mandated Global Change Research Act (GCRA) of 1990. Thirteen US government organizations participate in the NCA program which examines the effects of global change on the natural environment, human health and welfare, energy production and use, land and water resources, human social systems, transportation, agriculture, and biological diversity. The NCA focuses on natural and human-induced trends in global change, and projects major trends 25 to 100 years out. In support of the NCA, the NASA Marshall Space Flight Center (MSFC) continues to assess lightning-climate inter-relationships. This activity applies a variety of NASA assets to monitor in detail the changes in both the characteristics of ground- and space- based lightning observations as they pertain to changes in climate. In particular, changes in lightning characteristics over the conterminous US (CONUS) continue to be examined by this author using data from the Tropical Rainfall Measuring Mission Lightning Imaging Sensor. In this study, preliminary estimates of LNOx trends derived from TRMM/LIS lightning optical energy observations in the 17 yr period 1998-2014 are provided. This represents an important first step in testing the ability to make remote retrievals

  19. Characterization of infrasound from lightning

    Science.gov (United States)

    Assink, J. D.; Evers, L. G.; Holleman, I.; Paulssen, H.

    2008-08-01

    During thunderstorm activity in the Netherlands, electromagnetic and infrasonic signals are emitted due to the process of lightning and thunder. It is shown that correlating infrasound detections with results from a electromagnetic lightning detection network is successful up to distances of 50 km from the infrasound array. Infrasound recordings clearly show blastwave characteristics which can be related to cloud-ground discharges, with a dominant frequency between 1-5 Hz. Amplitude measurements of CG discharges can partly be explained by the beam pattern of a line source with a dominant frequency of 3.9 Hz, up to a distance of 20 km. The ability to measure lightning activity with infrasound arrays has both positive and negative implications for CTBT verification purposes. As a scientific application, lightning studies can benefit from the worldwide infrasound verification system.

  20. Terrestrial gamma-ray flash production by lightning

    Science.gov (United States)

    Carlson, Brant E.

    Terrestrial gamma-ray flashes (TGFs) are brief flashes of gamma-rays originating in the Earth's atmosphere and observed by satellites. First observed in 1994 by the Burst And Transient Source Experiment on board the Compton Gamma-Ray Observatory, TGFs consist of one or more ˜1 ms pulses of gamma-rays with a total fluence of ˜1/cm2, typically observed when the satellite is near active thunderstorms. TGFs have subsequently been observed by other satellites to have a very hard spectrum (harder than dN/d E ∝ 1/ E ) that extends from below 25 keV to above 20 MeV. When good lightning data exists, TGFs are closely associated with measurable lightning discharge. Such discharges are typically observed to occur within 300 km of the sub-satellite point and within several milliseconds of the TGF observation. The production of these intense energetic bursts of photons is the puzzle addressed herein. The presence of high-energy photons implies a source of bremsstrahlung, while bremsstrahlung implies a source of energetic electrons. As TGFs are associated with lightning, fields produced by lightning are naturally suggested to accelerate these electrons. Initial ideas about TGF production involved electric fields high above thunderstorms as suggested by upper atmospheric lightning research and the extreme energies required for lower-altitude sources. These fields, produced either quasi-statically by charges in the cloud and ionosphere or dynamically by radiation from lightning strokes, can indeed drive TGF production, but the requirements on the source lightning are too extreme and therefore not common enough to account for all existing observations. In this work, studies of satellite data, the physics of energetic electron and photon production, and consideration of lightning physics motivate a new mechanism for TGF production by lightning current pulses. This mechanism is then developed and used to make testable predictions. TGF data from satellite observations are compared

  1. Lightning safety awareness of visitors in three California national parks.

    Science.gov (United States)

    Weichenthal, Lori; Allen, Jacoby; Davis, Kyle P; Campagne, Danielle; Snowden, Brandy; Hughes, Susan

    2011-09-01

    To assess the level of lightning safety awareness among visitors at 3 national parks in the Sierra Nevada Mountains of California. A 12-question, short answer convenience sample survey was administered to participants 18 years of age and over concerning popular trails and points of interest with known lightning activity. There were 6 identifying questions and 5 knowledge-based questions pertaining to lightning that were scored on a binary value of 0 or 1 for a total of 10 points for the survey instrument. Volunteers in Fresno, California, were used as a control group. Participants were categorized as Sequoia and Kings Canyon National Park (SEKI), frontcountry (FC), or backcountry (BC); Yosemite National Park (YNP) FC or BC; and Fresno. Analysis of variance (ANOVA) was used to test for differences between groups. 467 surveys were included for analysis: 77 in Fresno, 192 in SEKI, and 198 in YNP. National park participants demonstrated greater familiarity with lightning safety than individuals from the metropolitan community (YNP 5.84 and SEKI 5.65 vs Fresno 5.14, P = .0032). There were also differences noted between the BC and FC subgroups (YNP FC 6.07 vs YNP BC 5.62, P = .02; YNP FC 6.07 vs SEKI FC 5.58, P = .02). Overall results showed that participants had certain basic lightning knowledge but lacked familiarity with other key lightning safety recommendations. While there are statistically significant differences in lightning safety awareness between national parks and metropolitan participants, the clinical impact of these findings are debatable. This study provides a starting point for providing educational outreach to visitors in these national parks. Copyright © 2011 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.

  2. Possible linkage between supernovae, increased terrestrial lightning, and wildfire activity in the Late Miocene and Early Pleistocene

    Science.gov (United States)

    Thomas, B. C.; Feulner, G.; Melott, A. L.; Kirsten, T.; von Bloh, W.

    2017-12-01

    Radioisotopes from deep-sea deposits show that Earth was affected by nearby supernovae about 2.5 and 8 million years ago. Recent modelling work shows that high-energy particles from these events resulted in greatly enhanced ionization of the troposphere. This could have led to an increase in wildfires via more frequent lightning. Here we show that published data on global fire activity from charcoal records reveal a marked increase in wildfires around the times of the supernova explosions. We use a dynamic global vegetation model to assess the impact of increased lightning frequency on vegetation patterns, finding a patchy global decrease in tree cover. Regionally, vegetation changes are particularly pronounced in western North America, the Mediterranean, Central Asia, Northern Indochina, subtropical South America, Africa and Australia, and notably East Africa, in agreement with empirical evidence for a global shift towards savannas during the Pleistocene. Our results demonstrate that moderately nearby supernovae have the potential to affect life on Earth even if they are too distant to initiate a mass extinction. Finally, we note that the shift from forest to savannah biomes in the East African Rift Valley region has been tentatively linked to hominin evolution in this region.

  3. Optical characteristics of lightning and thunderstorm currents

    Science.gov (United States)

    Krider, E. P.; Blakeslee, R. J.

    1985-01-01

    Researchers determined that lightning can be used to determine the diurnal variations of thunderstorms, i.e., storms that produce audible thunder, and that these variations are also in good agreement with diurnal variations in rainfall and convective activity. Measurements of the Maxwell current density, J sub m, under active thunderstorms show that this physical quantity is quasi-steady between lightning discharges and that lightning does not produce large changes in J sub m. Maps of J sub m show contours of iso-current density that are consistent with the locations of radar echos and the locations of where lightning has altered the cloud charge distribution.

  4. Cloud-to-Ground Lightning Estimates Derived from SSMI Microwave Remote Sensing and NLDN

    Science.gov (United States)

    Winesett, Thomas; Magi, Brian; Cecil, Daniel

    2015-01-01

    Lightning observations are collected using ground-based and satellite-based sensors. The National Lightning Detection Network (NLDN) in the United States uses multiple ground sensors to triangulate the electromagnetic signals created when lightning strikes the Earth's surface. Satellite-based lightning observations have been made from 1998 to present using the Lightning Imaging Sensor (LIS) on the NASA Tropical Rainfall Measuring Mission (TRMM) satellite, and from 1995 to 2000 using the Optical Transient Detector (OTD) on the Microlab-1 satellite. Both LIS and OTD are staring imagers that detect lightning as momentary changes in an optical scene. Passive microwave remote sensing (85 and 37 GHz brightness temperatures) from the TRMM Microwave Imager (TMI) has also been used to quantify characteristics of thunderstorms related to lightning. Each lightning detection system has fundamental limitations. TRMM satellite coverage is limited to the tropics and subtropics between 38 deg N and 38 deg S, so lightning at the higher latitudes of the northern and southern hemispheres is not observed. The detection efficiency of NLDN sensors exceeds 95%, but the sensors are only located in the USA. Even if data from other ground-based lightning sensors (World Wide Lightning Location Network, the European Cooperation for Lightning Detection, and Canadian Lightning Detection Network) were combined with TRMM and NLDN, there would be enormous spatial gaps in present-day coverage of lightning. In addition, a globally-complete time history of observed lightning activity is currently not available either, with network coverage and detection efficiencies varying through the years. Previous research using the TRMM LIS and Microwave Imager (TMI) showed that there is a statistically significant correlation between lightning flash rates and passive microwave brightness temperatures. The physical basis for this correlation emerges because lightning in a thunderstorm occurs where ice is first

  5. [Lightning strikes and lightning injuries in prehospital emergency medicine. Relevance, results, and practical implications].

    Science.gov (United States)

    Hinkelbein, J; Spelten, O; Wetsch, W A

    2013-01-01

    Up to 32.2% of patients in a burn center suffer from electrical injuries. Of these patients, 2-4% present with lightning injuries. In Germany, approximately 50 people per year are injured by a lightning strike and 3-7 fatally. Typically, people involved in outdoor activities are endangered and affected. A lightning strike usually produces significantly higher energy doses as compared to those in common electrical injuries. Therefore, injury patterns vary significantly. Especially in high voltage injuries and lightning injuries, internal injuries are of special importance. Mortality ranges between 10 and 30% after a lightning strike. Emergency medical treatment is similar to common electrical injuries. Patients with lightning injuries should be transported to a regional or supraregional trauma center. In 15% of all cases multiple people may be injured. Therefore, it is of outstanding importance to create emergency plans and evacuation plans in good time for mass gatherings endangered by possible lightning.

  6. Small, Continual Lightning Activity in the Overshooting Turret of Supercell Storms

    Science.gov (United States)

    Macgorman, D.; Kuhlman, K.; Bruning, E.; Rust, D.; Krehbiel, P.; Rison, B.

    2007-12-01

    Several supercell storms have occurred within the region in which the Oklahoma Lightning Mapping Array (OKLMA) maps all three spatial dimensions of lightning. These storms span much of the supercell spectrum -- from non-tornadic storms to storms that produced strong tornadoes and from low-precipitation to heavy- precipitation morphologies. As noted by several studies, supercell storms tend to have much larger flash rates than ordinary isolated thunderstorms; maximum rates are typically hundreds of flashes per minute, even when considering only flashes that produce at least ten mapped points per flash. However, the OKLMA indicates that most of the flashes occurring within the main body of the storm during periods of high flash rates have quite small spatial extents, many with a long dimension of 3-10 km. Not usually included in these flash rates are a large number that appear to be isolated points (sometimes called singletons), each failing criteria of distance or time for associating it with other points in a flash. Often determining whether these isolated points are artifacts of the OKLMA is difficult, but in the overshooting top, they present a coherent pattern that appears plausible. They are distributed throughout a cap having horizontal dimensions comparable to that of the overshooting top and sitting near or on the upper surface. They occur continually, though they are too far apart in time or space to be associated in a flash with each other. A comparison with high-resolution reflectivity data for one storm observed by the two mobile 5-cm wavelength SMART-R radars shows that these isolated points were most concentrated near the top of the 40 dBZ echo in the overshooting turret, but some occurred higher, in regions of small reflectivity or just above the overshooting top. These points may be similar to the continual lightning noted by Bill Taylor in the upper region of a severe storm in the early 1980s.

  7. Signatures in Lightning Activity during Tennessee Valley Severe Storms of 5-6 May 2003

    Science.gov (United States)

    Gatlin, Patrick N.; Goodman, Steven J.

    2004-01-01

    During the first week of May 2003, the Tennessee Valley experienced 14 tornadoes. Those that moved across the Tennessee Valley Region of northern Alabama and southern Tennessee provided an opportunity for study us- ing the North Alabama Lightning Mapping Array (LMA). On 5 May a classic supercell trekked across southern Tennessee spawning several tornadoes producing FO-F3 damage; on 6 May a high precipitation supercell moved across northern Alabama producing several FO-F1 tornadoes. The life cycle of these supercells will be discussed by presenting their electrical and radar evolution.

  8. The life-cycle of hailstorms: Lightning, radar reflectivity and rotation characteristics

    Science.gov (United States)

    Wapler, Kathrin

    2017-09-01

    An 8-year analysis of hailstorms is presented. A comprehensive set of six hundred hailstorms that occurred in 172 different days in various parts of Germany is used to characterise these events. The analysed observations include measurements from a lightning location system, precipitation radar, as well as information from automated cell detection algorithms based on radar reflectivity and radial winds which are combined with severe weather reports. Additionally to the storms' parameters during the time of the observed hail, the temporal evolution of the storms' characteristics is analysed in order to study the convective life-cycle and identify parameters with predictive skill. A special focus is on the lightning characteristics of the convective cells. A feature that is shown to occur in many of the analysed severe hail cases is the lightning jump, i.e., a rapid increase in the total lightning density. It occurs well before the observed hail and has thus a great potential to increase the lead time of warnings of severe hail events. Instead of fixed thresholds for the definition of a lightning jump, a lightning jump intensity parameter is introduced and tested. The analysis also reveals that half to the storms show a pulsating lightning activity. Nearly three quarters of the hail events are associated with a mesocyclone that was automatically detected in radar data. As expected, high reflectivity values were measured during the time of the observed hail.

  9. The NASA Thunderstorm Observations and Research (ThOR) Mission: Lightning Mapping from Space to Improve the Short-term Forecasting of Severe Storms

    Science.gov (United States)

    Goodman, S. J.; Christian, H. J.; Boccippio, D. J.; Koshak, W. J.; Cecil, D. J.; Arnold, James E. (Technical Monitor)

    2002-01-01

    The ThOR mission uses a lightning mapping sensor in geostationary Earth orbit to provide continuous observations of thunderstorm activity over the Americas and nearby oceans. The link between lightning activity and cloud updrafts is the basis for total lightning observations indicating the evolving convective intensification and decay of storms. ThOR offers a national operational demonstration of the utility of real-time total lightning mapping for earlier and more reliable identification of potentially severe and hazardous storms. Regional pilot projects have already demonstrated that the dominance in-cloud lightning and increasing in-cloud lash rates are known to precede severe weather at the surface by tens of minutes. ThOR is currently planned for launch in 2005 on a commercial or research satellite. Real-time data will be provided to selected NWS Weather Forecast Offices and National Centers (EMC/AWC/SPC) for evaluation.

  10. The Houston Lightning Mapping Array: Installation, Operation, and Preliminary Results

    Science.gov (United States)

    Orville, R. E.; Cullen, M. R.; Rodeheffer, D.; Krehbiel, P. R.; Rison, W.

    2012-12-01

    The Houston Lightning Mapping Array (LMA) was established in April 2012 and is a network of twelve time-of-arrival lightning sensors operating in the VHF around Houston, Texas. The network sensors are built by New Mexico Institute of Mining and Technology. Built stand-alone units, these LMA sensors use solar panels and cellular data modems for Internet connectivity. This enables the units to be placed in strategic locations at sites to minimize noise and interference by reducing dependence on wired power or communications lines. Twelve sensors are distributed around the Houston and provide total lightning data for the fourth most populated American city. The primary research goals of the network are to investigate the structure of total lightning within thunderstorm development and to examine any potential impact of the urban environment on lightning characteristics. Furthermore, the proximity to the coast and the Gulf of Mexico presents the opportunity to examine the total lightning structure within tropical cyclones that impact the Texas coastline. The availability of real-time LMA data provides a decision support tool for advanced warning of thunderstorm development. We present efforts with the Houston/Galveston Weather Forecast Office and the Spaceflight Meteorology Group at Johnson Space Center to integrate the real-time LMA data into operational display software. The network of 12 sensors has been operating continuously since installation in mid-April with 10 sensors surrounding the Houston area plus one in College Station and one in Galveston. Analysis of recent data will investigate three-dimensional thunderstorm activity.

  11. The North Alabama Lightning Mapping Array: Recent Severe Storm Observations and Future Prospects

    Science.gov (United States)

    Goodman, S. J.; Blakeslee, R.; Christian, H.; Koshak, W.; Bailey, J.; Hall, J.; McCaul, E.; Buechler, D.; Darden, C.; Burks, J.

    2004-01-01

    The North Alabama Lightning Mapping Array became operational in November 2001 as a principal component of a severe weather test bed to infuse new science and technology into the short-term forecasting of severe and hazardous weather, principally within nearby National Weather Service forecast offices. Since the installation of the LMA, it has measured the total lightning activity of a large number of severe weather events, including three supercell tornado outbreaks, two supercell hailstorm events, and numerous microburst-producing storms and ordinary non-severe thunderstorms. The key components of evolving storm morphology examined are the time rate-of-change (temporal trending) of storm convective and precipitation characteristics that can be diagnosed in real-time using NEXRAD WSR-88D Doppler radar (echo growth and decay, precipitation structures and velocity features, outflow boundaries), LMA (total lightning flash rate and its trend) and National Lightning Detection Network (cloud-to- ground lightning, its polarity and trends). For example, in a transitional season supercell tornado outbreak, peak total flash rates for typical supercells in Tennessee reached 70-100/min, and increases in the total flash rate occurred during storm intensification as much as 20-25 min prior to at least some of the tornadoes. The most intense total flash rate measured during this outbreak (over 800 flashes/min) occurred in a storm in Alabama. In the case of a severe summertime pulse thunderstorm in North Alabama, the peak total flash rate reached 300/min, with a strong increase in total lightning evident some 9 min before damaging winds were observed at the surface. In this paper we provide a sampling of LMA observations and products during severe weather events to illustrate the capability of the system, and discuss the prospects for improving the short-term forecasting of convective weather using total lightning data.

  12. Lightning Applications in Weather and Climate Research

    Science.gov (United States)

    Price, Colin G.

    2013-11-01

    Thunderstorms, and lightning in particular, are a major natural hazard to the public, aviation, power companies, and wildfire managers. Lightning causes great damage and death every year but also tells us about the inner working of storms. Since lightning can be monitored from great distances from the storms themselves, lightning may allow us to provide early warnings for severe weather phenomena such as hail storms, flash floods, tornadoes, and even hurricanes. Lightning itself may impact the climate of the Earth by producing nitrogen oxides (NOx), a precursor of tropospheric ozone, which is a powerful greenhouse gas. Thunderstorms themselves influence the climate system by the redistribution of heat, moisture, and momentum in the atmosphere. What about future changes in lightning and thunderstorm activity? Many studies show that higher surface temperatures produce more lightning, but future changes will depend on what happens to the vertical temperature profile in the troposphere, as well as changes in water balance, and even aerosol loading of the atmosphere. Finally, lightning itself may provide a useful tool for tracking climate change in the future, due to the nonlinear link between lightning, temperature, upper tropospheric water vapor, and cloud cover.

  13. Lightning activity with rainfall during El Nino and La Nina events over India

    Science.gov (United States)

    Tinmaker, M. I. R.; Aslam, M. Y.; Ghude, Sachin D.; Chate, D. M.

    2017-10-01

    This paper appraises the association of lightning flash count (FC) with rainfall using the satellite-borne Lightning Imaging Sensor's (LIS) data along with gridded rainfall data (0.5o × 0.5o) for Indian summer monsoon seasons over 10 years (2001-2010). During strong El Nino years, 2002 and 2009, FCs were greater in magnitude by about 26.5 % and 37 %, than the long-term average, respectively, while during weak El Nino year (2004), it was more by 8 %. During the same years, the rainfall was deficient by about 10 % than the long-term average. Similarly, a rise in aerosol optical depth (AOD) over its average value (by about 15 % and 20 %) reduces the ratio of rainfall to FC (RLR) by 41 % and 44 % for strong El Nino years 2002 and 2009, respectively, and for weak El Nino year (2004), a 6.5 % rise in AOD lowers the RLR by 20 %. Bowen ratio more by 11 % and 17 % of its average value reduces the RLR by 41 % and 44 % for strong El Nino years 2002 and 2009, respectively, and, also, Bowen ratio higher by 8 % for 2004 declines RLR by 20 %. On the other hand, Bowen ratio less by 9 % and 6 % raises the RLR by 19 % and 56 % for moderate La Nina year (2007) and strong La Nina year (2010), respectively. Results for the daily rainfall, AOD and Bowen ratio over Indian regions, are discussed for strong El Nino and La Nina years. Correlations of FC with AOD and Bowen ratio of 0.66 and 0.71, respectively, while, that of FC with ONI of 0.56 indicates numerous (fewer) break days during El Nino (La Nina) years.

  14. Disposition of Lightning Activity Due to Pollution Load during Dissimilar Seasons as Observed from Satellite and Ground-Based Data

    Directory of Open Access Journals (Sweden)

    Anirban Middey

    2016-05-01

    Full Text Available The precise role of air pollution on the climate and local weather has been an issue for quite a long time. Among the diverse issues, the effects of air pollution on lightning are of recent interest. Exploration over several years (2004 to 2011 has been made over Gangetic West Bengal of India using lightning flash data from TRMM-LIS (Tropical Rainfall Measuring Mission-Lightning Imaging Sensor, atmospheric pollutants, and rainfall data during pre-monsoon (April and May and monsoon (June, July, August and September seasons. Near-surface pollutants such as PM10 and SO2 have a good positive association with aerosol optical depth (AOD for both the pre-monsoon and monsoon months. High atmospheric aerosol loading correlates well with pre-monsoon and monsoon lightning flashes. However, rainfall has a dissimilar effect on lightning flashes. Flash count is positively associated with pre-monsoon rainfall (r = 0.64, but the reverse relation (r = −0.4 is observed for monsoon rainfall. Apart from meteorological factors, wet deposition of atmospheric pollutant may be considered a crucial factor for decreased lightning flash count in monsoon. The variation in the monthly average tropospheric column amount of NO2, from the Tropospheric Emission Monitoring Internet Service (TEMIS, is synchronic with average lightning flash rate. It has a good linear association with flash count for both pre-monsoon and monsoon seasons. The effect of lightning on tropospheric NO2 production is evident from the monthly average variation in NO2 on lightning and non-lightning days.

  15. A model for lightning in littoral areas

    NARCIS (Netherlands)

    Blaj, M.A.; Leferink, Frank Bernardus Johannes

    2009-01-01

    The littoral or coastal areas are different compared to the maritime or continental areas considering lightning. Only the last years some research about these areas has been carried out. The need for a model, regarding the lightning activity in these areas is much needed. And now, with the changes

  16. High Impact Weather Forecasts and Warnings with the GOES-R Geostationary Lightning Mapper (GLM)

    Science.gov (United States)

    Goodman, Steven; Blakeslee, Richard; Koshak, William; Mach, Douglas

    2011-01-01

    The Geostationary Operational Environmental Satellite (GOES-R) is the next series to follow the existing GOES system currently operating over the Western Hemisphere. A major advancement over the current GOES include a new capability for total lightning detection (cloud and cloud-to-ground flashes) from the Geostationary Lightning Mapper (GLM). The GLM will operate continuously day and night with near-uniform spatial resolution of 8 km with a product refresh rate of less than 20 sec over the Americas and adjacent oceanic regions. This will aid in forecasting severe storms and tornado activity, and convective weather impacts on aviation safety and efficiency. In parallel with the instrument development, a GOES-R Risk Reduction Science Team and Algorithm Working Group Lightning Applications Team have begun to develop cal/val performance monitoring tools and new applications using the GLM alone, in conjunction with other instruments, and merged or blended integrated observing system products combining satellite, radar, in-situ and numerical models. Proxy total lightning data from the NASA Lightning Imaging Sensor (LIS) on the Tropical Rainfall Measuring Mission (TRMM) satellite and regional ground-based lightning networks are being used to develop the pre-launch algorithms, test data sets, and applications, as well as improve our knowledge of thunderstorm initiation and evolution. In this presentation we review the planned implementation of the instrument and suite of operational algorithms.

  17. The saptio-temporal distribution of lightning over the southern Levant and its relation to the regional synoptic systems

    Science.gov (United States)

    Shalev, S.; Izsak, T.; Saaroni, H.; Yair, Y.; Ziv, B.

    2010-09-01

    The saptio-temporal distribution of lightning flashes over the southern Levant is derived from data obtained from the Lightning Positioning and Tracking System (LPATS) operated by the Israeli Electrical Company (IEC). The system has an aerial coverage in a range of ~ 500 Km around central Israel, including the southeastern Mediterranean Sea, Israel, Lebanon, western Syria and Jordan and the eastern part of Sinai Peninsula and the Red Sea. The study period includes 4 years. The spatial distribution of lightning flash density indicated the highest concentration over the sea, and is attributed to the contribution of sensible and latent heat fluxes. Other centers of high flash density appear along the coastal plain, expressing the friction effect of the coastline, and along orographic barriers, especially in northern Israel. The intra-annual distribution shows a complete absence of lightning in the eastern Mediterranean during the summer (JJA) which is due to the persistent existence of the subtropical high above the region. The vast majority of the lightning activity occurs during 7 months between October and April. Even though over 65% of the rainfall is obtained in the winter months (DJF) only 35% of the lightning is obtained in the winter and October is the richest month, with 40% of total annual number of lightning flashes. This is attributed mostly to tropical intrusions, i.e., Red Sea Trough (RST), which is characterized by high static instability. Cyprus lows are the synoptic system contributing the vast majority, >80%, of the rainfall in Israel, but only 42% of the lightning, whereas the RST, a minor contributor of rainfall, shares 48% of the lightning. However, during the winter 66% of the lightning flashes are associated with Cyprus lows and 25% with RST while during the autumn months the ratio is reversed: only 27% are associated with Cyprus lows and the majority (63%) occurs during RST. It was found that over 80% of the days defined as Cyprus lows were

  18. National Athletic Trainers' Association position statement: lightning safety for athletics and recreation.

    Science.gov (United States)

    Walsh, Katie M; Cooper, Mary Ann; Holle, Ron; Rakov, Vladimir A; Roeder, William P; Ryan, Michael

    2013-01-01

    To present recommendations for the education, prevention, and management of lightning injuries for those involved in athletics or recreation. Lightning is the most common severe-storm activity encountered annually in the United States. The majority of lightning injuries can be prevented through an aggressive educational campaign, vacating outdoor activities before the lightning threat, and an understanding of the attributes of a safe place from the hazard. This position statement is focused on supplying information specific to lightning safety and prevention and treatment of lightning injury and providing lightning-safety recommendations for the certified athletic trainer and those who are involved in athletics and recreation.

  19. Lightning injuries in sports and recreation.

    Science.gov (United States)

    Thomson, Eric M; Howard, Thomas M

    2013-01-01

    The powers of lightning have been worshiped and feared by all known human cultures. While the chance of being struck by lightning is statistically very low, that risk becomes much greater in those who frequently work or play outdoors. Over the past 2 yr, there have been nearly 50 lightning-related deaths reported within the United States, with a majority of them associated with outdoor recreational activities. Recent publications primarily have been case studies, review articles, and a discussion of a sixth method of injury. The challenge in reducing lightning-related injuries in organized sports has been addressed well by both the National Athletic Trainers' Association and the National Collegiate Athletic Association in their guidelines on lightning safety. Challenges remain in educating the general population involved in recreational outdoor activities that do not fall under the guidelines of organized sports.

  20. Tropic lightning: myth or menace?

    Science.gov (United States)

    McCarthy, John

    2014-11-01

    Lightning is one of the leading causes of death related to environmental disaster. Of all lightning fatalities documented between 2006 and 2012, leisure activities contributed the largest proportion of deaths, with water-associated, sports, and camping being the most common. Despite the prevalence of these activities throughout the islands, Hawai'i has had zero documented lightning fatalities since weather data tracking was initiated in 1959. There is a common misconception that lightning does not strike the ground in Hawai'i. This myth may contribute to a potentially dangerous false sense of security, and recognition of warning signs and risk factor modification remain the most important prevention strategies. Lightning damage occurs on a spectrum, from minor burns to multi-organ dysfunction. After injury, initial treatment should focus on "reverse triage" and immediate cardiopulmonary resuscitation when indicated, followed by transfer to a healthcare facility. Definitive treatment entails monitoring and management of potential sequelae, to include cardiovascular, neurologic, dermatologic, ophthalmologic, audiovestibular, and psychiatric complications.

  1. Spatio-temporal dimension of lightning flashes based on three-dimensional Lightning Mapping Array

    Science.gov (United States)

    López, Jesús A.; Pineda, Nicolau; Montanyà, Joan; Velde, Oscar van der; Fabró, Ferran; Romero, David

    2017-11-01

    3D mapping system like the LMA - Lightning Mapping Array - are a leap forward in lightning observation. LMA measurements has lead to an improvement on the analysis of the fine structure of lightning, allowing to characterize the duration and maximum extension of the cloud fraction of a lightning flash. During several years of operation, the first LMA deployed in Europe has been providing a large amount of data which now allows a statistical approach to compute the full duration and horizontal extension of the in-cloud phase of a lightning flash. The "Ebro Lightning Mapping Array" (ELMA) is used in the present study. Summer and winter lighting were analyzed for seasonal periods (Dec-Feb and Jun-Aug). A simple method based on an ellipse fitting technique (EFT) has been used to characterize the spatio-temporal dimensions from a set of about 29,000 lightning flashes including both summer and winter events. Results show an average lightning flash duration of 440 ms (450 ms in winter) and a horizontal maximum length of 15.0 km (18.4 km in winter). The uncertainties for summer lightning lengths were about ± 1.2 km and ± 0.7 km for the mean and median values respectively. In case of winter lightning, the level of uncertainty reaches up to 1 km and 0.7 km of mean and median value. The results of the successful correlation of CG discharges with the EFT method, represent 6.9% and 35.5% of the total LMA flashes detected in summer and winter respectively. Additionally, the median value of lightning lengths calculated through this correlative method was approximately 17 km for both seasons. On the other hand, the highest median ratios of lightning length to CG discharges in both summer and winter were reported for positive CG discharges.

  2. A proposed experiment on ball lightning model

    Energy Technology Data Exchange (ETDEWEB)

    Ignatovich, Vladimir K., E-mail: v.ignatovi@gmail.com [Frank Laboratory for Neutron Physics, Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); Ignatovich, Filipp V. [1565 Jefferson Rd., 420, Rochester, NY 14623 (United States)

    2011-09-19

    Highlights: → We propose to put a glass sphere inside an excited gas. → Then to put a light ray inside the glass in a whispering gallery mode. → If the light is resonant to gas excitation, it will be amplified at every reflection. → In ms time the light in the glass will be amplified, and will melt the glass. → A liquid shell kept integer by electrostriction forces is the ball lightning model. -- Abstract: We propose an experiment for strong light amplification at multiple total reflections from active gaseous media.

  3. Visual Analytics approach for Lightning data analysis and cell nowcasting

    Science.gov (United States)

    Peters, Stefan; Meng, Liqiu; Betz, Hans-Dieter

    2013-04-01

    Thunderstorms and their ground effects, such as flash floods, hail, lightning, strong wind and tornadoes, are responsible for most weather damages (Bonelli & Marcacci 2008). Thus to understand, identify, track and predict lightning cells is essential. An important aspect for decision makers is an appropriate visualization of weather analysis results including the representation of dynamic lightning cells. This work focuses on the visual analysis of lightning data and lightning cell nowcasting which aim to detect and understanding spatial-temporal patterns of moving thunderstorms. Lightnings are described by 3D coordinates and the exact occurrence time of lightnings. The three-dimensionally resolved total lightning data used in our experiment are provided by the European lightning detection network LINET (Betz et al. 2009). In all previous works, lightning point data, detected lightning cells and derived cell tracks are visualized in 2D. Lightning cells are either displayed as 2D convex hulls with or without the underlying lightning point data. Due to recent improvements of lightning data detection and accuracy, there is a growing demand on multidimensional and interactive visualization in particular for decision makers. In a first step lightning cells are identified and tracked. Then an interactive graphic user interface (GUI) is developed to investigate the dynamics of the lightning cells: e.g. changes of cell density, location, extension as well as merging and splitting behavior in 3D over time. In particular a space time cube approach is highlighted along with statistical analysis. Furthermore a lightning cell nowcasting is conducted and visualized. The idea thereby is to predict the following cell features for the next 10-60 minutes including location, centre, extension, density, area, volume, lifetime and cell feature probabilities. The main focus will be set to a suitable interactive visualization of the predicted featured within the GUI. The developed visual

  4. Lightning enhancement over major oceanic shipping lanes

    Science.gov (United States)

    Thornton, Joel A.; Virts, Katrina S.; Holzworth, Robert H.; Mitchell, Todd P.

    2017-09-01

    Using 12 years of high-resolution global lightning stroke data from the World Wide Lightning Location Network (WWLLN), we show that lightning density is enhanced by up to a factor of 2 directly over shipping lanes in the northeastern Indian Ocean and the South China Sea as compared to adjacent areas with similar climatological characteristics. The lightning enhancement is most prominent during the convectively active season, November-April for the Indian Ocean and April-December in the South China Sea, and has been detectable from at least 2005 to the present. We hypothesize that emissions of aerosol particles and precursors by maritime vessel traffic lead to a microphysical enhancement of convection and storm electrification in the region of the shipping lanes. These persistent localized anthropogenic perturbations to otherwise clean regions are a unique opportunity to more thoroughly understand the sensitivity of maritime deep convection and lightning to aerosol particles.

  5. The lightning flash

    CERN Document Server

    Cooray, Vernon

    2014-01-01

    With contributions from today's leading lightning engineers and researchers, this updated 2nd edition of Vernon Cooray's classic text, The Lightning Flash provides the reader with an essential introduction to lightning and its impact on electrical and electronic equipment. Providing the reader with a thorough background into almost every aspect of lightning and its impact on electrical and electronic equipment, this new edition is updated throughout and features eight new chapters that bring the science up to date.

  6. Lightning safety of animals.

    Science.gov (United States)

    Gomes, Chandima

    2012-11-01

    This paper addresses a concurrent multidisciplinary problem: animal safety against lightning hazards. In regions where lightning is prevalent, either seasonally or throughout the year, a considerable number of wild, captive and tame animals are injured due to lightning generated effects. The paper discusses all possible injury mechanisms, focusing mainly on animals with commercial value. A large number of cases from several countries have been analyzed. Economically and practically viable engineering solutions are proposed to address the issues related to the lightning threats discussed.

  7. New Physical Mechanism for Lightning

    Science.gov (United States)

    Artekha, Sergey N.; Belyan, Andrey V.

    2018-02-01

    The article is devoted to electromagnetic phenomena in the atmosphere. The set of experimental data on the thunderstorm activity is analyzed. It helps to identify a possible physical mechanism of lightning flashes. This mechanism can involve the formation of metallic bonds in thunderclouds. The analysis of the problem is performed at a microphysical level within the framework of quantum mechanics. The mechanism of appearance of metallic conductivity includes the resonant tunneling of electrons along resonance-percolation trajectories. Such bonds allow the charges from the vast cloud charged subsystems concentrate quickly in lightning channel. The formation of metal bonds in the thunderstorm cloudiness is described as the second-order phase transition. A successive mechanism for the process of formation and development of the lightning channel is suggested. This mechanism is associated with the change in the orientation of crystals in growing electric field. Possible consequences of the quantum-mechanical mechanism under discussion are compared with the results of observations.

  8. Acoustic Manifestations of Natural versus Triggered Lightning

    Science.gov (United States)

    Arechiga, R. O.; Johnson, J. B.; Edens, H. E.; Rison, W.; Thomas, R. J.; Eack, K.; Eastvedt, E. M.; Aulich, G. D.; Trueblood, J.

    2010-12-01

    Positive leaders are rarely detected by VHF lightning detection systems; positive leader channels are usually outlined only by recoil events. Positive cloud-to-ground (CG) channels are usually not mapped. The goal of this work is to study the types of thunder produced by natural versus triggered lightning and to assess which types of thunder signals have electromagnetic activity detected by the lightning mapping array (LMA). Towards this end we are investigating the lightning detection capabilities of acoustic techniques, and comparing them with the LMA. In a previous study we used array beam forming and time of flight information to locate acoustic sources associated with lightning. Even though there was some mismatch, generally LMA and acoustic techniques saw the same phenomena. To increase the database of acoustic data from lightning, we deployed a network of three infrasound arrays (30 m aperture) during the summer of 2010 (August 3 to present) in the Magdalena mountains of New Mexico, to monitor infrasound (below 20 Hz) and audio range sources due to natural and triggered lightning. The arrays were located at a range of distances (60 to 1400 m) surrounding the triggering site, called the Kiva, used by Langmuir Laboratory to launch rockets. We have continuous acoustic measurements of lightning data from July 20 to September 18 of 2009, and from August 3 to September 1 of 2010. So far, lightning activity around the Kiva was higher during the summer of 2009. We will present acoustic data from several interesting lightning flashes including a comparison between a natural and a triggered one.

  9. Global Frequency and Distribution of Lightning as Observed from Space by the Optical Transient Detector

    Science.gov (United States)

    Christian, Hugh J.; Blakeslee, Richard J.; Boccippio, Dennis J.; Boeck, William L.; Bucchler, Dennis E.; Driscoll, Kevin T.; Goodman, Steven J.; Hall, John M.; Koshak, William J.; Mach, Douglas M.; hide

    2002-01-01

    The Optical Transient Detector (OTD) is a space-based instrument specifically designed to detect and locate lightning discharges as it orbits the Earth. This instrument is a scientific payload on the MicroLab-1 satellite that was launched into a low-earth, 70 deg. inclination orbit in April 1995. Given the orbital trajectory of the satellite, most regions of the earth are observed by the OTD instrument more than 400 times during a one year period, and the average duration of each observation is 2 minutes. The OTD instrument optically detects lightning flashes that occur within its 1300x1300 sq km field-of-view during both day and night conditions. A statistical examination of OTD lightning data reveals that nearly 1.4 billion flashes occur annually over the entire earth. This annual flash count translates to an average of 44 +/- 5 lightning flashes (intracloud and cloud-to-ground combined) occurring around the globe every second, which is well below the traditional estimate of 100 flashes per second that was derived in 1925 from world thunder-day records. The range of uncertainty for the OTD global totals represents primarily the uncertainty (and variability) in the flash detection efficiency of the instrument. The OTD measurements have been used to construct lightning climatology maps that demonstrate the geographical and seasonal distribution of lightning activity for the globe. An analysis of this annual lightning distribution confirms that lightning occurs mainly over land areas, with an average land:ocean ratio of 10:1. A dominant Northern Hemisphere summer peak occurs in the annual cycle, and evidence is found for a tropically-driven semiannual cycle.

  10. Recent Advancements in Lightning Jump Algorithm Work

    Science.gov (United States)

    Schultz, Christopher J.; Petersen, Walter A.; Carey, Lawrence D.

    2010-01-01

    In the past year, the primary objectives were to show the usefulness of total lightning as compared to traditional cloud-to-ground (CG) networks, test the lightning jump algorithm configurations in other regions of the country, increase the number of thunderstorms within our thunderstorm database, and to pinpoint environments that could prove difficult for any lightning jump configuration. A total of 561 thunderstorms have been examined in the past year (409 non-severe, 152 severe) from four regions of the country (North Alabama, Washington D.C., High Plains of CO/KS, and Oklahoma). Results continue to indicate that the 2 lightning jump algorithm configuration holds the most promise in terms of prospective operational lightning jump algorithms, with a probability of detection (POD) at 81%, a false alarm rate (FAR) of 45%, a critical success index (CSI) of 49% and a Heidke Skill Score (HSS) of 0.66. The second best performing algorithm configuration was the Threshold 4 algorithm, which had a POD of 72%, FAR of 51%, a CSI of 41% and an HSS of 0.58. Because a more complex algorithm configuration shows the most promise in terms of prospective operational lightning jump algorithms, accurate thunderstorm cell tracking work must be undertaken to track lightning trends on an individual thunderstorm basis over time. While these numbers for the 2 configuration are impressive, the algorithm does have its weaknesses. Specifically, low-topped and tropical cyclone thunderstorm environments are present issues for the 2 lightning jump algorithm, because of the suppressed vertical depth impact on overall flash counts (i.e., a relative dearth in lightning). For example, in a sample of 120 thunderstorms from northern Alabama that contained 72 missed events by the 2 algorithm 36% of the misses were associated with these two environments (17 storms).

  11. Total's LNG activities from Algeria to Yemen

    International Nuclear Information System (INIS)

    Vedrenne, J.P.

    1997-01-01

    In March 1995, further to an international tender, Total was awarded the leadership of the first LNG project in Yemen. On January 1997 Total announced the extension of the share-holding of the Yemen LNG Co. to include the companies with interests in the Marib area (Hunt-Exxon-Yukong). The Marib area will supply the gas to the future liquefaction plant. The ratification of these agreements confirms the role of Total as lead shareholder with 36% in the share-holding structure and guarantees gas supply from the Marib licence, operated by Hunt-Exxon. (author)

  12. Lightning Mapping and the Nowcasting of Severe Storms

    Science.gov (United States)

    Goodman, S.; Darden, C.; Burks, J.

    2005-01-01

    This paper describes a successful research and operational collaboration between NASA scientists and NWS forecasters to improve severe stor m warnings using real-time data from a regional VHF total lightning mapping array (LMA). Key objectives of our research using LMA data ar e: a) Identification of intensifying and weakening storms using the time rate-of-change of total flash rate; b) Improved severe storm poten tial situational awareness; c) Evaluation of the potential of total f lash rate trend to improve severe storm probability of detection (POD ) and lead time; and d) Validation of mesoscale model forecasts of th understorm initiation. The LMA data are distributed for ingest and di splay in the WFO AWIPS decision support system, and archived at each WFO for case studies, event playbacks, and assessments using the NWS Warning Event Simulator. The Huntsville WFO has upgraded severe thund erstorm warnings to verified tornado warnings and avoided a false ala rm on a severe storm through the added information on storm growth, intensification, and decay that can be deduced from the magnitude and temporal trend of total flash rates. We present detailed case studies of the observed relationships between lightning activity and tornadi c storm development as determined by radar reflectivity and velocity fields, and thunderstorms forecast by the Weather Research and Foreca st (WRF) model. From these collaborative studies, forecasters can eva luate the added value of total lightning data within the forecast and warning decision-making process (http://weather.msfc.nasa.gov/sport) .

  13. Lightning protection for wind turbines in Vietnam

    Directory of Open Access Journals (Sweden)

    Thuan Nguyen

    2017-01-01

    Full Text Available Wind energy has become increasingly important in the total electrical energy supply mix in Vietnam over the last few years. Small, kW turbines were installed in isolated areas a decade ago, while wind farms of several MW to few hundred MW are now being connected directly to national grid, with many additional projects in planning or under construction to fulfill an objective of 6% of the total installed capacity by 2030 (approximately 6200 MW of wind energy component. The increase in wind farm generation results in increased damage from lightning. In this paper, the annual frequency of lightning strikes to wind turbines in Vietnam is calculated using electrogeometric model. Reported lightning incidents to three major wind farms in Vietnam are summarized. Possible causes of failure are discussed, and an EMTP simulation for each incident was performed accordingly. The simulations suggest the failure mechanisms as well the potential of improved grounding to reduce lightning induced damage in future windfarms.

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

    Science.gov (United States)

    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.

  15. LIS 0.1 DEGREE VERY HIGH RESOLUTION GRIDDED LIGHTNING FULL CLIMATOLOGY (VHRFC) V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The LIS 0.1 Degree Very High Resolution Gridded Lightning Full Climatology (VHRFC) dataset consists of gridded full climatologies of total lightning flash rates seen...

  16. LIS 0.1 DEGREE VERY HIGH RESOLUTION GRIDDED LIGHTNING SEASONAL CLIMATOLOGY (VHRSC) V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The LIS 0.1 Degree Very High Resolution Gridded Lightning Seasonal Climatology (VHRSC) dataset consists of gridded seasonal climatologies of total lightning flash...

  17. LIS 0.1 DEGREE VERY HIGH RESOLUTION GRIDDED LIGHTNING ANNUAL CLIMATOLOGY (VHRAC) V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The LIS 0.1 Degree Very High Resolution Gridded Lightning Annual Climatology (VHRAC) dataset consists of gridded annual climatologies of total lightning flash rates...

  18. LIS 0.1 DEGREE VERY HIGH RESOLUTION GRIDDED LIGHTNING MONTHLY CLIMATOLOGY (VHRMC) V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The LIS 0.1 Degree Very High Resolution Gridded Lightning Monthly Climatology (VHRMC) dataset consists of gridded monthly climatologies of total lightning flash...

  19. LIS 0.1 DEGREE VERY HIGH RESOLUTION GRIDDED LIGHTNING DIURNAL CLIMATOLOGY (VHRDC) V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The LIS 0.1 Degree Very High Resolution Gridded Lightning Diurnal Climatology (VHRDC) dataset consists of gridded diurnal climatologies of total lightning flash...

  20. Lightning characteristics observed by a VLF/LF lightning detection network (LINET in Brazil, Australia, Africa and Germany

    Directory of Open Access Journals (Sweden)

    H. Höller

    2009-10-01

    Full Text Available This paper describes lightning characteristics as obtained in four sets of lightning measurements during recent field campaigns in different parts of the world from mid-latitudes to the tropics by the novel VLF/LF (very low frequency/low frequency lightning detection network (LINET. The paper gives a general overview on the approach, and a synopsis of the statistical results for the observation periods as a whole and for one special day in each region. The focus is on the characteristics of lightning which can specifically be observed by this system like intra-cloud and cloud-to-ground stroke statistics, vertical distributions of intra-cloud strokes or peak current distributions. Some conclusions regarding lightning produced NOx are also presented as this was one of the aims of the tropical field campaigns TROCCINOX (Tropical Convection, Cirrus and Nitrogen Oxides Experiment and TroCCiBras (Tropical Convection and Cirrus Experiment Brazil in Brazil during January/February 2005, SCOUT-O3 (Stratospheric-Climate Links with Emphasis on the Upper Troposphere and Lower Stratosphere and TWP-ICE (Tropical Warm Pool-International Cloud Experiment during November/December 2005 and January/February 2006, respectively, in the Darwin area in N-Australia, and of AMMA (African Monsoon Multidisciplinary Analyses in W-Africa during June–November 2006.

    Regional and temporal characteristics of lightning are found to be dependent on orographic effects (e.g. S-Germany, Brazil, Benin, land-sea breeze circulations (N-Australia and especially the evolution of the monsoons (Benin, N-Australia. Large intra-seasonal variability in lightning occurrence was found for the Australian monsoon between the strong convection during build-up and break phases and the weak active monsoon phase with only minor lightning activity. Total daily lightning stroke rates can be of comparable intensity in all regions with the heaviest events found in Germany and N

  1. Weekly Cycle of Lightning: Evidence of Storm Invigoration by Pollution

    Science.gov (United States)

    Bell, Thomas L.; Rosenfeld, Daniel; Kim, Kyu-Myong

    2009-01-01

    We have examined summertime 1998 2009 U.S. lightning data from the National Lightning Detection Network (NLDN) to look for weekly cycles in lightning activity. As was found by Bell et al. (2008) for rain over the southeast U.S., there is a significant weekly cycle in afternoon lightning activity that peaks in the middle of the week there. The weekly cycle appears to be reduced over population centers. Lightning activity peaks on weekends over waters near the SE U.S. The statistical significance of weekly cycles over the western half of the country is generally small. We found no evidence of a weekly cycle of synoptic-scale forcing that might explain these patterns. The lightning behavior is entirely consistent with the explanation suggested by Bell et al. (2008) for the cycles in rainfall and other atmospheric data from the SE U.S., that aerosols can cause storms to intensify in humid, convectively unstable environments.

  2. A projected decrease in lightning under climate change

    Science.gov (United States)

    Finney, Declan L.; Doherty, Ruth M.; Wild, Oliver; Stevenson, David S.; MacKenzie, Ian A.; Blyth, Alan M.

    2018-02-01

    Lightning strongly influences atmospheric chemistry1-3, and impacts the frequency of natural wildfires4. Most previous studies project an increase in global lightning with climate change over the coming century1,5-7, but these typically use parameterizations of lightning that neglect cloud ice fluxes, a component generally considered to be fundamental to thunderstorm charging8. As such, the response of lightning to climate change is uncertain. Here, we compare lightning projections for 2100 using two parameterizations: the widely used cloud-top height (CTH) approach9, and a new upward cloud ice flux (IFLUX) approach10 that overcomes previous limitations. In contrast to the previously reported global increase in lightning based on CTH, we find a 15% decrease in total lightning flash rate with IFLUX in 2100 under a strong global warming scenario. Differences are largest in the tropics, where most lightning occurs, with implications for the estimation of future changes in tropospheric ozone and methane, as well as differences in their radiative forcings. These results suggest that lightning schemes more closely related to cloud ice and microphysical processes are needed to robustly estimate future changes in lightning and atmospheric composition.

  3. Postmaterialism Influencing Total Entrepreneurial Activity across Nations

    NARCIS (Netherlands)

    L.M. Uhlaner (Lorraine); A.R. Thurik (Roy)

    2006-01-01

    textabstractThe relative stability of differences in entrepreneurial activity across countries suggests that other than economic factors are at play. The objective of this paper is to explore how postmaterialism may explain these differences. A distinction is made between nascent entrepreneurship,

  4. Laboratory-produced ball lightning

    Science.gov (United States)

    Golka, Robert K., Jr.

    1994-05-01

    For 25 years I have actively been searching for the true nature of ball lightning and attempting to reproduce it at will in the laboratory. As one might expect, many unidentified lights in the atmosphere have been called ball lightning, including Texas Maffa lights (automobile headlights), flying saucers (UFOs), swamp gas in Ann Arbor, Michigan, etc. For 15 years I thought ball lightning was strictly a high-voltage phenomenon. It was not until 1984 when I was short-circuiting the electrical output of a diesel electric railroad locomotive that I realized that the phenomenon was related more to a high current. Although I am hoping for some other types of ball lightning to emerge such as strictly electrostatic-electromagnetic manifestations, I have been unlucky in finding laboratory provable evidence. Cavity-formed plasmodes can be made by putting a 2-inch burning candle in a home kitchen microwave oven. The plasmodes float around for as long as the microwave energy is present.

  5. Lightning phenomenology in the Tampa Bay Area

    Science.gov (United States)

    Peckham, D. W.; Uman, M. A.; Wilcox, C. E., Jr.

    1984-01-01

    A commercial lightning-locating system (LLS) was employed in the study of lightning phenomenology in the Tampa Bay area of Florida. The LLS output included the time, location, number of strokes per flash, and initial peak magnetic field value of first strokes for lightning ground flashes lowering negative charge. Attention is given to the design and the operation of the LLS, and the experimental results. Measured properties of each of 111 storms are given in a number of tables. It was observed that the apparent motion associated with the lightning activity in storm systems was not due to the motion of the individual single-peak and multiple-peak storms but rather to the successive growth of new storms near previously active storms.

  6. TRMM-Based Lightning Climatology

    Science.gov (United States)

    Cecil, Daniel J.; Buechler, Dennis E.; Blakeslee, Richard J.

    2011-01-01

    Gridded climatologies of total lightning flash rates seen by the spaceborne Optical Transient Detector (OTD) and Lightning Imaging Sensor (LIS) have been updated. OTD collected data from May 1995 to March 2000. LIS data (equatorward of about 38 deg) has been added for 1998-2010. Flash counts from each instrument are scaled by the best available estimates of detection efficiency. The long LIS record makes the merged climatology most robust in the tropics and subtropics, while the high latitude data is entirely from OTD. The mean global flash rate from the merged climatology is 46 flashes per second. The peak annual flash rate at 0.5 deg scale is 160 fl/square km/yr in eastern Congo. The peak monthly average flash rate at 2.5 scale is 18 fl/square km/mo, from early April to early May in the Brahmaputra Valley of far eastern India. Lightning decreases in this region during the monsoon season, but increases further north and west. A monthly average peak from early August to early September in northern Pakistan also exceeds any monthly averages from Africa, despite central Africa having the greatest yearly average. Most continental regions away from the equator have an annual cycle with lightning flash rates peaking in late spring or summer. The main exceptions are India and southeast Asia, with springtime peaks in April and May. For landmasses near the equator, flash rates peak near the equinoxes. For many oceanic regions, the peak flash rates occur in autumn. This is particularly noticeable for the Mediterranean and North Atlantic. Landmasses have a strong diurnal cycle of lightning, with flash rates generally peaking between 3-5 pm local solar time. The central United States flash rates peak later, in late evening or early night. Flash rates peak after midnight in northern Argentina. These regions are known for large, intense, long-lived mesoscale convective systems.

  7. Using Cloud-to-Ground Lightning Climatologies to Initialize Gridded Lightning Threat Forecasts for East Central Florida

    Science.gov (United States)

    Lambert, Winnie; Sharp, David; Spratt, Scott; Volkmer, Matthew

    2005-01-01

    Each morning, the forecasters at the National Weather Service in Melbourn, FL (NWS MLB) produce an experimental cloud-to-ground (CG) lightning threat index map for their county warning area (CWA) that is posted to their web site (http://www.srh.weather.gov/mlb/ghwo/lightning.shtml) . Given the hazardous nature of lightning in central Florida, especially during the warm season months of May-September, these maps help users factor the threat of lightning, relative to their location, into their daily plans. The maps are color-coded in five levels from Very Low to Extreme, with threat level definitions based on the probability of lightning occurrence and the expected amount of CG activity. On a day in which thunderstorms are expected, there are typically two or more threat levels depicted spatially across the CWA. The locations of relative lightning threat maxima and minima often depend on the position and orientation of the low-level ridge axis, forecast propagation and interaction of sea/lake/outflow boundaries, expected evolution of moisture and stability fields, and other factors that can influence the spatial distribution of thunderstorms over the CWA. The lightning threat index maps are issued for the 24-hour period beginning at 1200 UTC (0700 AM EST) each day with a grid resolution of 5 km x 5 km. Product preparation is performed on the AWIPS Graphical Forecast Editor (GFE), which is the standard NWS platform for graphical editing. Currently, the forecasters create each map manually, starting with a blank map. To improve efficiency of the forecast process, NWS MLB requested that the Applied Meteorology Unit (AMU) create gridded warm season lightning climatologies that could be used as first-guess inputs to initialize lightning threat index maps. The gridded values requested included CG strike densities and frequency of occurrence stratified by synoptic-scale flow regime. The intent is to increase consistency between forecasters while enabling them to focus on

  8. Lightning signature as an index for the determination of the ...

    African Journals Online (AJOL)

    West African rains are mainly due to the squall-line activities. Squall lines are groups of active thunderstorm clouds that are aligned with the ITCZ in front. The clouds are electrically active and 90% of lightning recorded occurs during squall lines associated thunderstorms. The results of measurements of lightning count from ...

  9. When lightning strikes: bolting down the facts & fiction.

    Science.gov (United States)

    Usatch, Ben

    2009-04-01

    MYTH: There's no danger from lightning until the rain starts. FACT: Lightning often precedes the storm by up to 10 miles. A reasonable guideline is the "30-30 rule," by which you count the seconds between the flash and the thunder. If the time span is less than 30 seconds, seek shelter. Additionally, wait a full 30 minutes from last lightning flash to resume outdoor activities.

  10. The Elusive Evidence of Volcanic Lightning.

    Science.gov (United States)

    Genareau, K; Gharghabi, P; Gafford, J; Mazzola, M

    2017-11-14

    Lightning strikes are known to morphologically alter and chemically reduce geologic formations and deposits, forming fulgurites. A similar process occurs as the result of volcanic lightning discharge, when airborne volcanic ash is transformed into lightning-induced volcanic spherules (LIVS). Here, we adapt the calculations used in previous studies of lightning-induced damage to infrastructure materials to determine the effects on pseudo-ash samples of simplified composition. Using laboratory high-current impulse experiments, this research shows that within the lightning discharge channel there is an ideal melting zone that represents roughly 10% or less of the total channel radius at which temperatures are sufficient to melt the ash, regardless of peak current. The melted ash is simultaneously expelled from the channel by the heated, expanding air, permitting particles to cool during atmospheric transport before coming to rest in ash fall deposits. The limited size of this ideal melting zone explains the low number of LIVS typically observed in volcanic ash despite the frequent occurrence of lightning during explosive eruptions.

  11. Lightning Behavior and its Dependence on Storm Kinematic and Precipitation Processes in Northern Alabama

    Science.gov (United States)

    Johnson, Elsie V.; Petersen, W. A,

    2009-01-01

    Numerous case studies and recent modeling studies have found that various metrics of updraft intensity appear to be reasonably well correlated to lightning production in thunderstorms, particularly severe thunderstorms. Indeed, the relationship between updraft and lightning flash rate is hypothesized to be the physical connection between a lightning "jump" signature and manifestations of severe weather such as tornadic activity. This study further examines this connection using a combination of dual Doppler wind retrievals made with the UAH ARMOR dual polarimetric and KHTX WSR 88D Doppler radar pair, together with northern Alabama Lightning Mapping Array (LMA) data. The dual Doppler data were used to construct three dimensional wind fields and the retrieved vertical velocity fields were subsequently compared to collocated total lightning flash rates observed by the LMA. Particular attention was paid to the timing of updraft pulses relative to changes in the flash rate, with the goal of assessing impacts on warning decision lead time. Results from the analysis of severe and non severe thunderstorms in Northern Alabama will be presented including the EF 4 tornado producing supercell on 6 February 2008.

  12. Lightning Observations from the International Space Station (ISS) for Science Research and Operational Applications

    Science.gov (United States)

    Blakeslee, R. J.; Christian, H. J.; Mach, D. M.; Buechler, D. E.; Koshak, W. J.; Walker, T. D.; Bateman, M.; Stewart, M. F.; O'Brien, S.; Wilson, T.; hide

    2015-01-01

    There exist several core science applications of LIS lightning observations, that range from weather and climate to atmospheric chemistry and lightning physics due to strong quantitative connections that can be made between lightning and other geophysical processes of interest. The space-base vantage point, such as provided by ISS LIS, still remains an ideal location to obtain total lightning observations on a global basis.

  13. The use of a potential lightning index in multi-microphysical cloud-resolving simulations of a V-shape convective system.

    Science.gov (United States)

    Lagasio, Martina; Parodi, Antonio; Procopio, Renato; Rachidi, Farhad; Fiori, Elisabetta

    2017-04-01

    Lightning activity is a characteristic phenomenon of severe weather as confirmed by many studies on different weather regimes that reveal strong interplay between lightning phenomena and extreme rainfall process in thunderstorms. The improvement of the so-called total (i.e. cloud-to-ground and intra-cloud) lightning observation systems in the last decades has allowed to investigate the relationship between the lightning flash rate and the kinematic and microphysical properties of severe hydro-meteorological events characterized by strong convection. V-shape back-building Mesoscale Convective Systems (MCSs) occurring over short periods of time have hit several times the Liguria region located in north-western Italy in the period between October 2010 and November 2014, generating flash-flood events responsible for hundreds of fatalities and millions of euros of damage. All these events showed an area of intense precipitation sweeping an arc of a few degrees around the warm conveyor belt originating about 50-60 km from the Liguria coastline. A second main ingredient was the presence of a convergence line, which supported the development and the maintenance of the aforementioned back-building process. Other common features were the persistence of such geometric configuration for many hours and the associated strong lightning activity. A methodological approach for the evaluation of these types of extreme rainfall and lightning convective events is presented for a back-building MCS event occurred in Genoa in 2014. A microphysics driven ensemble of WRF simulations at cloud-permitting grid spacing (1 km) with different microphysics parameterizations is used and compared to the available observational radar and lightning data. To pursue this aim, the performance of the Lightning Potential Index (LPI) as a measure of the potential for charge generation and separation that leads to lightning occurrence in clouds, is computed and analyzed to gain further physical insight in

  14. Lightning injury: a review.

    Science.gov (United States)

    Ritenour, Amber E; Morton, Melinda J; McManus, John G; Barillo, David J; Cancio, Leopoldo C

    2008-08-01

    Lightning is an uncommon but potentially devastating cause of injury in patients presenting to burn centers. These injuries feature unusual symptoms, high mortality, and significant long-term morbidity. This paper will review the epidemiology, physics, clinical presentation, management principles, and prevention of lightning injuries.

  15. Lightning Often Strikes Twice

    Science.gov (United States)

    2005-01-01

    Contrary to popular misconception, lightning often strikes the same place twice. Certain conditions are just ripe for a bolt of electricity to come zapping down; and a lightning strike is powerful enough to do a lot of damage wherever it hits. NASA created the Accurate Location of Lightning Strikes technology to determine the ground strike point of lightning and prevent electrical damage in the immediate vicinity of the Space Shuttle launch pads at Kennedy Space Center. The area surrounding the launch pads is enmeshed in a network of electrical wires and components, and electronic equipment is highly susceptible to lightning strike damage. The accurate knowledge of the striking point is important so that crews can determine which equipment or system needs to be retested following a strike. Accurate to within a few yards, this technology can locate a lightning strike in the perimeter of the launch pad. As an added bonus, the engineers, then knowing where the lightning struck, can adjust the variables that may be attracting the lightning, to create a zone that will be less susceptible to future strikes.

  16. Volcanic Lightning in Eruptions of Sakurajima Volcano

    Science.gov (United States)

    Edens, Harald; Thomas, Ronald; Behnke, Sonja; McNutt, Stephen; Smith, Cassandra; Farrell, Alexandra; Van Eaton, Alexa; Cimarelli, Corrado; Cigala, Valeria; Eack, Ken; Aulich, Graydon; Michel, Christopher; Miki, Daisuke; Iguchi, Masato

    2016-04-01

    In May 2015 a field program was undertaken to study volcanic lightning at the Sakurajima volcano in southern Japan. One of the main goals of the study was to gain a better understanding of small electrical discharges in volcanic eruptions, expanding on our earlier studies of volcanic lightning at Augustine and Redoubt volcanoes in Alaska, USA, and Eyjafjallajökull in Iceland. In typical volcanic eruptions, electrical activity occurs at the onset of an eruption as a near-continual production of VHF emissions at or near to the volcanic vent. These emissions can occur at rates of up to tens of thousands of emissions per second, and are referred to as continuous RF. As the ash cloud expands, small-scale lightning flashes of several hundred meters length begin to occur while the continuous RF ceases. Later on during the eruption larger-scale lightning flashes may occur within the ash cloud that are reminiscent of regular atmospheric lightning. Whereas volcanic lightning flashes are readily observed and reasonably well understood, the nature and morphology of the events producing continuous RF are unknown. During the 2015 field program we deployed a comprehensive set of instrumentation, including a 10-station 3-D Lightning Mapping Array (LMA) that operated in 10 μs high time resolution mode, slow and fast ΔE antennas, a VHF flat-plate antenna operating in the 20-80 MHz band, log-RF waveforms within the 60-66 MHz band, an infra-red video camera, a high-sensitivity Watec video camera, two high-speed video cameras, and still cameras. We give an overview of the Sakurajima field program and present preliminary results using correlated LMA, waveforms, photographs and video recordings of volcanic lightning at Sakurajima volcano.

  17. The Intra-Cloud Lightning Fraction in the Contiguous United States

    Science.gov (United States)

    Medici, Gina; Cummins, Kenneth L.; Koshak, William J.; Rudlosky, Scott D.; Blakeslee, Richard J.; Goodman, Steven J.; Cecil, Daniel J.; Bright, David R.

    2015-01-01

    Lightning is dangerous and destructive; cloud-to-ground (CG) lightning flashes can start fires, interrupt power delivery, destroy property and cause fatalities. Its rate-of-occurrence reflects storm kinematics and microphysics. For decades lightning research has been an important focus, and advances in lightning detection technology have been essential contributors to our increasing knowledge of lightning. A significant step in detection technology is the Geostationary Lightning Mapper (GLM) to be onboard the Geostationary Operational Environment Satellite R-Series (GOES-R) to be launched in early 2016. GLM will provide continuous "Total Lightning" observations [CG and intra-cloud lightning (IC)] with near-uniform spatial resolution over the Americas by measuring radiance at the cloud tops from the different types of lightning. These Total Lightning observations are expected to significantly improve our ability to nowcast severe weather. It may be important to understand the long-term regional differences in the relative occurrence of IC and CG lightning in order to understand and properly use the short-term changes in Total Lightning flash rate for evaluating individual storms.

  18. Nowcasting of Lightning-Related Accidents in Africa

    Science.gov (United States)

    Ihrlich, Laura; Price, Colin

    2016-04-01

    Tropical Africa is the world capital of thunderstorm activity with the highest density of strikes per square kilometer per year. As a result it is also the continent with perhaps the highest casualties and injuries from direct lightning strikes. This region of the globe also has little lightning protection of rural homes and schools, while many casualties occur during outdoor activities (e.g. farming, fishing, sports, etc.) In this study we investigated two lightning-caused accidents that got wide press coverage: A lightning strike to a Cheetah Center in Namibia which caused a huge fire and great destruction (16 October 2013), and a plane crash in Mali where 116 people died (24 July 2014). Using data from the World Wide Lightning Location Network (WWLLN) we show that the lightning data alone can provide important early warning information that can be used to reduce risks and damages and loss of life from lightning strikes. We have developed a now-casting scheme that allows for early warnings across Africa with a relatively low false alarm rate. To verify the accuracy of our now-cast, we have performed some statistical analysis showing relatively high skill at providing early warnings (lead time of a few hours) based on lightning alone. Furthermore, our analysis can be used in forensic meteorology for determining if such accidents are caused by lightning strikes.

  19. Infrasound Observations from Lightning

    Science.gov (United States)

    Arechiga, R. O.; Johnson, J. B.; Edens, H. E.; Thomas, R. J.; Jones, K. R.

    2008-12-01

    To provide additional insight into the nature of lightning, we have investigated its infrasound manifestations. An array of three stations in a triangular configuration, with three sensors each, was deployed during the Summer of 2008 (July 24 to July 28) in the Magdalena mountains of New Mexico, to monitor infrasound (below 20 Hz) sources due to lightning. Hyperbolic formulations of time of arrival (TOA) measurements and interferometric techniques were used to locate lightning sources occurring over and outside the network. A comparative analysis of simultaneous Lightning Mapping Array (LMA) data and infrasound measurements operating in the same area was made. The LMA locates the sources of impulsive RF radiation produced by lightning flashes in three spatial dimensions and time, operating in the 60 - 66 MHz television band. The comparison showed strong evidence that lightning does produce infrasound. This work is a continuation of the study of the frequency spectrum of thunder conducted by Holmes et al., who reported measurements of infrasound frequencies. The integration of infrasound measurements with RF source localization by the LMA shows great potential for improved understanding of lightning processes.

  20. Lightning in aeronautics

    International Nuclear Information System (INIS)

    Lago, F

    2014-01-01

    It is generally accepted that a civilian aircraft is struck, on average, once or twice per year. This number tends to indicate that a lightning strike risk is far from being marginal and so requires that aircraft manufacturers have to demonstrate that their aircraft is protected against lightning. The first generation of aircrafts, which were manufactured mainly in aluminium alloy and had electromechanical and pneumatic controls, had a natural immunity to the effects of lightning. Nowadays, aircraft structures are made primarily with composite materials and flight controls are mostly electronic. This aspect of the ''more composite and more electric'' aircraft demands to aircraft manufacturers to pay a particular attention to the lightning protection and to its certification by testing and/or analysis. It is therefore essential to take this risk into account when designing the aircraft. Nevertheless, it is currently impossible to reproduce the entire lightning phenomenon in testing laboratories and the best way to analyse the lightning protection is to reproduce its effects. In this context, a number of standards and guides are produced by standards committees to help laboratories and aircraft manufacturers to perform realistic tests. Although the environment of a laboratory is quite different from those of a storm cloud, the rules of aircraft design, the know-how of aircraft manufacturers, the existence of international work leading to a better understanding of the lightning phenomenon and standards more precise, permit, today, to consider the risk as properly controlled

  1. Preliminary lightning observations over Greece

    Science.gov (United States)

    Chronis, Themis G.

    2012-02-01

    The first Precision Lightning Network, monitoring the Cloud-to-Ground (CG) lightning stroke activity over Greece and surrounding waters is operated and maintained by the Hellenic National Meteorological Service. This paper studies the regional (land/water interface), seasonal and diurnal variability of the CG strokes as a function of density, polarity and peak current. Additional investigation uniquely links the CG stroke current to sea surface salinity and cloud electrical capacitance. In brief, this study's major findings area as follows: (1) The seasonal maps of thunder days agree well with the regional climatic convective characteristics of the study area, (2) the CG diurnal variability is consistent with the global lightning activity observations over land and ocean, (3) the maxima of monthly averaged CG counts are located over land and water during typical summer and fall months respectively for both polarities, (4) CG peak currents show a distinct seasonality with larger currents during relatively colder months and smaller currents during summer months, and (5) strong linear trends between -CGs and sea surface salinity; (6) this trend is absent for +CGs data analysis of the employed database relate to the thunderstorm's RC constant and agrees with previous numerical modeling studies.

  2. Optimization of lightning warning areas at Cape Canaveral/Kennedy Space Center

    OpenAIRE

    Ceschini, Erin M.

    2013-01-01

    Approved for public release; distribution is unlimited Lightning is the primary weather hazard to spaceflight operations. At CCAFS/KSC, there are 13 individual lightning warning circles centered on locations with considerable outdoor operational activity. Reducing the number of individual lightning warning circles by combining existing warning circles or creating new warning areas based on lightning patterns has the potential benefit of reducing the workload of the forecasters on duty. How...

  3. Simulating lightning tests to radar system

    NARCIS (Netherlands)

    Blaj, M.A.; Buesink, Frederik Johannes Karel; Leferink, Frank Bernardus Johannes

    2010-01-01

    The risk of destruction due to lightning makes simulating the effects of lightning strikes a necessity. We modeled a radar enclosure and simulated the effect of a lightning strike. The results have been validated using full threat lightning current tests.

  4. Integration of Lightning- and Human-Caused Wildfire Occurrence Models

    DEFF Research Database (Denmark)

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

    2010-01-01

    Fire risk indices are useful tools for fire prevention actions by fire managers. A fire ignition is either the result of lightning or human activities. In European Mediterranean countries most forest fires are due to human activities. However, lightning is still an important fire ignition source...... in some regions. Integration of lightning and human fire occurrence probability into fire risk indices would be necessary to have a complete picture of the causal agents and their relative importance in fire occurrence. We present two methods for the integration of lightning and human fire occurrence...... probability models at 1 × 1 km grid cell resolution in two regions of Spain: Madrid, which presents a high fire incidence due to human activities; and Aragón, one of the most affected regions in Spain by lightning-fires. For validation, independent fire ignition points were used to compute the Receiver...

  5. Improving Lightning and Precipitation Prediction of Severe Convection Using Lightning Data Assimilation With NCAR WRF-RTFDDA

    Science.gov (United States)

    Wang, Haoliang; Liu, Yubao; Cheng, William Y. Y.; Zhao, Tianliang; Xu, Mei; Liu, Yuewei; Shen, Si; Calhoun, Kristin M.; Fierro, Alexandre O.

    2017-11-01

    In this study, a lightning data assimilation (LDA) scheme was developed and implemented in the National Center for Atmospheric Research Weather Research and Forecasting-Real-Time Four-Dimensional Data Assimilation system. In this LDA method, graupel mixing ratio (qg) is retrieved from observed total lightning. To retrieve qg on model grid boxes, column-integrated graupel mass is first calculated using an observation-based linear formula between graupel mass and total lightning rate. Then the graupel mass is distributed vertically according to the empirical qg vertical profiles constructed from model simulations. Finally, a horizontal spread method is utilized to consider the existence of graupel in the adjacent regions of the lightning initiation locations. Based on the retrieved qg fields, latent heat is adjusted to account for the latent heat releases associated with the formation of the retrieved graupel and to promote convection at the observed lightning locations, which is conceptually similar to the method developed by Fierro et al. Three severe convection cases were studied to evaluate the LDA scheme for short-term (0-6 h) lightning and precipitation forecasts. The simulation results demonstrated that the LDA was effective in improving the short-term lightning and precipitation forecasts by improving the model simulation of the qg fields, updrafts, cold pool, and front locations. The improvements were most notable in the first 2 h, indicating a highly desired benefit of the LDA in lightning and convective precipitation nowcasting (0-2 h) applications.

  6. Thunderstorm-/lightning-induced ionospheric perturbation: An observation from equatorial and low-latitude stations around Hong Kong

    Science.gov (United States)

    Kumar, Sanjay; Chen, Wu; Chen, Mingli; Liu, Zhizhao; Singh, R. P.

    2017-08-01

    Total electron content (TEC) computed from the network of Global Positioning System over Hong Kong area known as Hong Kong Sat-Ref-network has been used to study perturbation in the ionosphere from thunder storm activity. Data for geomagnetic quiet day (Kp lightning activity was measured from Total Lightning sensor LS8000 over/around the Hong Kong region. Deviation in vertical TEC (DTEC) and the rate of change of TEC index (ROTI) have been derived and compared for lightning day of 1 April 2014 and nonlightning day of 7 April 2014. An analysis showed reduction in TEC during evening hour (up to 1245 UT), whereas an enhancement during nighttime hour on the lightning day is observed. The variations in DTEC during nonlightning day are found to be insignificant in comparison to that during the lightning day. The ionospheric perturbation in TEC has been noticed up to a distance around 500 km and more from the lightning center. ROTI is found to vary from 3 to 60 total electron content unit (TECU)/min (1 TECU = 1016 el m-2) on the day of thunderstorm activity, whereas ROTI is insignificant on nonlightning days. Signature of density bubbles in slant TEC data and periodicities (10-100 min) in DTEC data are observed. For the same pseudorandom numbers (1, 10, 13, 23, and 28) strong amplitude scintillations are also observed at a close by station. Amplitude scintillations are proposed to be caused by plasma bubbles. The results are tentatively explained by thunderstorm-induced electric fields and gravity waves.

  7. Upward Lightning in Brazil

    Science.gov (United States)

    Schumann, C.; Saba, M. M.; Alves, J.; Warner, T. A.; Albrecht, R. I.; Bie, L. L.

    2012-12-01

    Observations of upward lightning from tall objects have been reported since 1939. Interest in this subject has grown recently, some of it because of the rapid expansion of wind power generation. Also, with the increasing number of tall buildings and towers, there will be a corresponding increase in the number of upward lightning flashes from these structures. Reports from recent field observations are beginning to address the nature of upward lightning initiation, but much still needs to be learned. Examples are studies of upward lightning from towers in winter thunderstorms in Japan (Wang and Takagi, 2010; and Lu et al., 2009) and summer thunderstorms in Europe (Miki et al., 2005; Flache et al., 2008; and Diendorfer et al., 2009; Zhou et al., 2011) and in North America (Mazur and Ruhnke, 2011; Hussein et al., 2011; Warner, 2011, and Warner et al., 2011). Up to January 2012, no upward flash had ever been registered in Brazil. With the help of some video cameras, we recorded 15 upward lightning which started from one of the towers located on Peak Jaraguá in the city of São Paulo. This paper describes the first results of this field campaign. A combination of high-speed video and standard definition video were used to record upward lightning flashes from multiple towers in Sao Paulo, Brazil, a city located in southeastern Brazil with a population over 10 million people, an average elevation of around 800 meters above sea level, and a flash density of 15 flashes/km2/year. Observations of 15 upward flashes made with these assets were analyzed along with BrasilDAT Lightning Detection Network and a lightning mapping array (LMA) and electric field sensors.

  8. Estimates of lightning NOx production from GOME satellite observations

    Directory of Open Access Journals (Sweden)

    K. F. Boersma

    2005-01-01

    Full Text Available Tropospheric NO2 column retrievals from the Global Ozone Monitoring Experiment (GOME satellite spectrometer are used to quantify the source strength and 3-D distribution of lightning produced nitrogen oxides (NOx=NO+NO2. A sharp increase of NO2 is observed at convective cloud tops with increasing cloud top height, consistent with a power-law behaviour with power 5±2. Convective production of clouds with the same cloud height are found to produce NO2 with a ratio 1.6/1 for continents compared to oceans. This relation between cloud properties and NO2 is used to construct a 10:30 local time global lightning NO2 production map for 1997. An extensive statistical comparison is conducted to investigate the capability of the TM3 chemistry transport model to reproduce observed patterns of lightning NO2 in time and space. This comparison uses the averaging kernel to relate modelled profiles of NO2 to observed NO2 columns. It exploits a masking scheme to minimise the interference of other NOx sources on the observed total columns. Simulations are performed with two lightning parameterizations, one relating convective preciptation (CP scheme to lightning flash distributions, and the other relating the fifth power of the cloud top height (H5 scheme to lightning distributions. The satellite-retrieved NO2 fields show significant correlations with the simulated lightning contribution to the NO2 concentrations for both parameterizations. Over tropical continents modelled lightning NO2 shows remarkable quantitative agreement with observations. Over the oceans however, the two model lightning parameterizations overestimate the retrieved NO2 attributed to lightning. Possible explanations for these overestimations are discussed. The ratio between satellite-retrieved NO2 and modelled lightning NO2 is used to rescale the original modelled lightning NOx production. Eight estimates of the lightning NOx production in 1997 are obtained from spatial and temporal

  9. Intracloud lightning data in Brazil using LF detection range: first results

    Science.gov (United States)

    Naccarato, K.; Pinto, O.

    2009-12-01

    Brazil installed in 2007/2008 two LS7000 new generation Vaisala sensors in State of São Paulo (Southeastern Brazil) and two LS8000 sensors in State of Paraná (Southern Brazil). The sensors are located in São José dos Campos/SP (LS7000), Cachoeira Paulista/SP (LS7000), Novo Horizonte/PR (LS8000) and Santa Terezinha/PR (LS8000). According to the manufacturer, they can provide about 30% of intracloud activity data using LF (100-400kHz) detection range. Previous studies demonstrated that the new generation sensors (LSX000 series) has a higher detection efficiency compared to the latter generation sensors (IMPACT series) with a significant increase in the number of cloud-to-ground (CG) strokes reported with peak current lower than 20kA. However, a fraction of these events are intracloud (IC) discharges, which can be used together with the CG lightning information to provide total lighting data in the LF range. In the present work, the lightning data were provided by all 49 network sensors (including the LSX000 sensors) based on the IC/CG discrimination default criteria adopted by the manufacturer (waveform peak-to-zero time). Figure 1 shows the peak current distribution of the lightning strokes in State of Sao Paulo including the new LS7000 sensors compared to the solutions using the old IMPACT sensors. The number of low peak current events (from -5kA to +5kA) detected by the network with the LS7000 is significantly higher. Based on these results, the temporal and spatial variations of the IC lightning will be evaluated and compared to the corresponding variations of the CG lightning. Figure 1 - IC/CG lightning detection from IMPACT sensors (gray line) and LS7000 sensors (black line) showing the IC detection between -5kA and +5kA.

  10. The physics of lightning

    Science.gov (United States)

    Dwyer, Joseph R.; Uman, Martin A.

    2014-01-01

    Despite being one of the most familiar and widely recognized natural phenomena, lightning remains relatively poorly understood. Even the most basic questions of how lightning is initiated inside thunderclouds and how it then propagates for many tens of kilometers have only begun to be addressed. In the past, progress was hampered by the unpredictable and transient nature of lightning and the difficulties in making direct measurements inside thunderstorms, but advances in instrumentation, remote sensing methods, and rocket-triggered lightning experiments are now providing new insights into the physics of lightning. Furthermore, the recent discoveries of intense bursts of X-rays and gamma-rays associated with thunderstorms and lightning illustrate that new and interesting physics is still being discovered in our atmosphere. The study of lightning and related phenomena involves the synthesis of many branches of physics, from atmospheric physics to plasma physics to quantum electrodynamics, and provides a plethora of challenging unsolved problems. In this review, we provide an introduction to the physics of lightning with the goal of providing interested researchers a useful resource for starting work in this fascinating field. By what physical mechanism or mechanisms is lightning initiated in the thundercloud? What is the maximum cloud electric field magnitude and over what volume of the cloud? What, if any, high energy processes (runaway electrons, X-rays, gamma rays) are involved in lightning initiation and how? What is the role of various forms of ice and water in lightning initiation? What physical mechanisms govern the propagation of the different types of lightning leaders (negative stepped, first positive, negative dart, negative dart-stepped, negative dart-chaotic) between cloud and ground and the leaders inside the cloud? What is the physical mechanism of leader attachment to elevated objects on the ground and to the flat ground? What are the characteristics

  11. The Physics of Lightning

    Science.gov (United States)

    Rakov, V. A.

    2013-11-01

    An overview of the physics of cloud-to-ground lightning is given, including its initiation, propagation, and attachment to ground. Discharges artificially initiated (triggered) from natural thunderclouds using the rocket-and-wire technique are discussed with a view toward studying properties of natural lightning. Both conventional and runaway breakdown mechanisms of lightning initiation in thunderclouds are reviewed, as is the role of the lower positive charge region in facilitating different types of lightning. New observations of negative-leader stepping and its attachment to ground are compared to similar processes in long laboratory sparks. The mechanism and parameters of compact intracloud lightning discharges that are thought to be the most intense natural producers of HF-VHF (3-300 MHz) radiation on Earth are reviewed. The M-component mode of charge transfer to ground and its difference from the leader/return-stroke mode are discussed. Lightning interaction with the ionosphere and the production of energetic radiation (X-rays and gamma radiation) by cloud-to-ground leaders are considered.

  12. Situational Lightning Climatologies

    Science.gov (United States)

    Bauman, William; Crawford, Winifred

    2010-01-01

    Research has revealed distinct spatial and temporal distributions of lightning occurrence that are strongly influenced by large-scale atmospheric flow regimes. It was believed there were two flow systems, but it has been discovered that actually there are seven distinct flow regimes. The Applied Meteorology Unit (AMU) has recalculated the lightning climatologies for the Shuttle Landing Facility (SLF), and the eight airfields in the National Weather Service in Melbourne (NWS MLB) County Warning Area (CWA) using individual lightning strike data to improve the accuracy of the climatologies. The software determines the location of each CG lightning strike with 5-, 10-, 20-, and 30-nmi (.9.3-, 18.5-, 37-, 55.6-km) radii from each airfield. Each CG lightning strike is binned at 1-, 3-, and 6-hour intervals at each specified radius. The software merges the CG lightning strike time intervals and distance with each wind flow regime and creates probability statistics for each time interval, radii, and flow regime, and stratifies them by month and warm season. The AMU also updated the graphical user interface (GUI) with the new data.

  13. Habitual physical activity and sports participation after total ankle arthroplasty.

    Science.gov (United States)

    Naal, Florian D; Impellizzeri, Franco M; Loibl, Markus; Huber, Martin; Rippstein, Pascal F

    2009-01-01

    There is a lack of detailed information about habitual physical activity levels and the sports participation of patients after total ankle arthroplasty. The proportion of sports active patients increases after total ankle arthroplasty, and the majority of patients will meet current recommendations for health-enhancing physical activity. Case series; Level of evidence, 4. The authors assessed the pre- and postoperative participation in sports and recreational activities of 101 patients at a mean of 3.7 years after total ankle arthroplasty. Activity levels were determined with use of the University of California at Los Angeles (UCLA) activity scale. The International Physical Activity Questionnaire (IPAQ) was used to quantify habitual physical activity levels and to calculate the proportion of patients meeting current guidelines for health-enhancing physical activity. The American Orthopaedic Foot and Ankle Society (AOFAS) hindfoot score was used as the clinical outcome measure. Radiographs were studied for tibial and talar radiolucencies, and any association between radiolucencies, activity levels, and sports participation was determined. Preoperatively, 62.4% of the patients were active in sports; 66.3% were active after surgery (P=.56). The patients were active in 3.0 +/- 1.8 different sports and recreational activities preoperatively and in 3.0 +/- 1.6 activities after surgery (P =1.0). The sports frequency remained unchanged, with 2.0 +/- 1.6 sessions per week before total ankle arthroplasty and 2.3 +/- 1.7 sessions per week postoperatively (P=.19). Overall, the patients were active in sports and recreation for 3.9 +/- 3.8 hours per week pre-operatively, and for 4.7 +/- 3.9 hours per week after surgery (P=.14). The most common disciplines after total ankle arthroplasty were swimming, cycling, and fitness/weight training. Sixty-five percent of the patients stated that surgery had improved their sports ability. The UCLA activity levels increased significantly from

  14. Decreased arylesterase activity and increased total Decreased arylesterase activity and increased total oxidative status in rosacea

    Directory of Open Access Journals (Sweden)

    Sertac Sener

    2017-10-01

    Full Text Available Background: Rosacea is an inflammatory skin disease of face. In recent years, it is revealed that imbalance is significant in oxidant/antioxidant system in pathophysiology. Objective: In this study, the role of oxidative stress on rosacea was investigated. Methods: 34 rosacea patients and 33 healthy control cases between 18 and 70 years old are included in the study. In all the cases, serum lipids, Paraoxonase1(PON1, stimulated Paraoxonase1(stPON1, Arylesterase(ARES, Total Oxidant Status (TOS and Total Antioxidant Status (TAS levels are measured. Results: ARES levels were significantly lower and TOS levels were significantly higher in the patient group (p<0,001. Oxidative Stress Index(OSI was found to be shifted towards the oxidative side in the patient group (p<0,001. Conclusion: This situation shows that oxidative stress may have a role in the rosacea pathophysiology

  15. Phytochemical screening, total phenolic, total flavonoids contents and antioxidant activity of cinchona ledgeriana leaves ethanol extract

    Science.gov (United States)

    Sundowo, Andini; Artanti, Nina; Hanafi, M.; Minarti, Primahana, Gian

    2017-11-01

    C ledgeriana is a medicinal plant that contains alkaloids, especially on the barks for commercial production of quinine as antimalarial. The main alkaloids in this plant are cinchonine, cinchonidine, quinine and quinidine. Besides for antiamalarial this plant is also commonly used to treat whooping cough, influenza and dysentery. Compare to other medicinal plants, nowadays only very few studies were conducted in Cinchona species. Our current study aims to determine the content of phytochemical, total phenol and total flavonoids from C. ledgeriana leaves 70% ethanol extract. The extraction was performed by maceration method using 70% ethanol solvent and then fractionated into hexane, ethylacetate and butanol. Phytochemical screening was performed to determine the content of alkaloids, flavonoids, terpenoids, tannins and saponins. Total phenol and flavonoid contents of the extract were determined by Folin-Ciocalteu and alumunium chloride colorimetric methods using gallic acid and quercetin as standards. The antioxidant activity was determined by using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. The results of phytochemical screening showed that the 70% ethanol extract of C. ledgeriana leaves contained alkaloids, flavonoids, terpenoids, tannins and saponins. The total phenol and total flavonoids analysis showed that ethyl acetate fraction had the highest total phenol (40.23%) and total flavonoids (65.34%).

  16. Lightning characteristics of derecho producing mesoscale convective systems

    Science.gov (United States)

    Bentley, Mace L.; Franks, John R.; Suranovic, Katelyn R.; Barbachem, Brent; Cannon, Declan; Cooper, Stonie R.

    2016-06-01

    Derechos, or widespread, convectively induced wind storms, are a common warm season phenomenon in the Central and Eastern United States. These damaging and severe weather events are known to sweep quickly across large spatial regions of more than 400 km and produce wind speeds exceeding 121 km h-1. Although extensive research concerning derechos and their parent mesoscale convective systems already exists, there have been few investigations of the spatial and temporal distribution of associated cloud-to-ground lightning with these events. This study analyzes twenty warm season (May through August) derecho events between 2003 and 2013 in an effort to discern their lightning characteristics. Data used in the study included cloud-to-ground flash data derived from the National Lightning Detection Network, WSR-88D imagery from the University Corporation for Atmospheric Research, and damaging wind report data obtained from the Storm Prediction Center. A spatial and temporal analysis was conducted by incorporating these data into a geographic information system to determine the distribution and lightning characteristics of the environments of derecho producing mesoscale convective systems. Primary foci of this research include: (1) finding the approximate size of the lightning activity region for individual and combined event(s); (2) determining the intensity of each event by examining the density and polarity of lightning flashes; (3) locating areas of highest lightning flash density; and (4) to provide a lightning spatial analysis that outlines the temporal and spatial distribution of flash activity for particularly strong derecho producing thunderstorm episodes.

  17. Using cloud ice flux to parametrise large-scale lightning

    Directory of Open Access Journals (Sweden)

    D. L. Finney

    2014-12-01

    Full Text Available Lightning is an important natural source of nitrogen oxide especially in the middle and upper troposphere. Hence, it is essential to represent lightning in chemistry transport and coupled chemistry–climate models. Using ERA-Interim meteorological reanalysis data we compare the lightning flash density distributions produced using several existing lightning parametrisations, as well as a new parametrisation developed on the basis of upward cloud ice flux at 440 hPa. The use of ice flux forms a link to the non-inductive charging mechanism of thunderstorms. Spatial and temporal distributions of lightning flash density are compared to tropical and subtropical observations for 2007–2011 from the Lightning Imaging Sensor (LIS on the Tropical Rainfall Measuring Mission (TRMM satellite. The well-used lightning flash parametrisation based on cloud-top height has large biases but the derived annual total flash density has a better spatial correlation with the LIS observations than other existing parametrisations. A comparison of flash density simulated by the different schemes shows that the cloud-top height parametrisation has many more instances of moderate flash densities and fewer low and high extremes compared to the other parametrisations. Other studies in the literature have shown that this feature of the cloud-top height parametrisation is in contrast to lightning observations over certain regions. Our new ice flux parametrisation shows a clear improvement over all the existing parametrisations with lower root mean square errors (RMSEs and better spatial correlations with the observations for distributions of annual total, and seasonal and interannual variations. The greatest improvement with the new parametrisation is a more realistic representation of the zonal distribution with a better balance between tropical and subtropical lightning flash estimates. The new parametrisation is appropriate for testing in chemistry transport and chemistry

  18. Changes in total carbohydrate and total antioxidant activity induced by gamma irradiation of wheat flour

    International Nuclear Information System (INIS)

    Manupriya, B.R.; Shenoy, K. Bhasker; Patil, Shrikant L.; Somashekarappa, H.M.

    2015-01-01

    Wheat is a staple food grain in India after rice and occupies number one position in the world. The wheat crop not only gives food grains but also gives fodder for animals. Among many preservation methods irradiation is a current technique used to overcome infestation, contamination and spoilage of stored grains. The present study is aimed to check the changes in composition of irradiated wheat flour. Wheat flour was exposed to five different irradiation doses (0.25 KGy, 0.5KGy, 1KGy, 5KGy and 10 KGy) by using 60 Co gamma-irradiation chamber. Irradiated flour was stored in air sealed polyethylene pouch and plastic container at room temperature for different time intervals (0 th day, 1 month and 3 months). The stored flour was checked for total antioxidant activity by phosphomolybdate method and total carbohydrates concentration by phenol-sulphuric acid method. On 0 th day total antioxidant activity and total carbohydrate concentration was found to be increased at 0.5KGy (0.113 mg/ml and 0.045 mg/ml respectively) when compared to control (0.79 mg/ml and 39.5 mg/ml). Similarly for 1 month stored samples of air sealed polyethylene pouch total antioxidant activity and total carbohydrate concentration was observed to be increased at 0.5KGy (0.117 mg/ml and 0.045mg/ml respectively) when compared to control (0.096 mg/ml and 0.035 mg/ml). But in case of stored samples of plastic container total antioxidant activity increased at 0.25KGy (0.060 mg/ml) and total carbohydrate increased at 5KGy (0.051 mg/ml). Increased and decreased values were found in both factors for 3 months stored samples of air sealed polyethylene pouch and plastic container. Total antioxidant activity increased at 5KGy (0.072 mg/ml) for polyethylene bag samples and at 0.5KGy (0.137 mg/ml) for plastic container sample. Same way total carbohydrate concentration increased at 0.25KGy (0.046 mg/ml) and at 1KGy (0.045 mg/ml) respectively. This increase is due to affects of γ-irradiation on biomolecules by

  19. The start of lightning: Evidence of bidirectional lightning initiation

    OpenAIRE

    Montany?, Joan; van der Velde, Oscar; Williams, Earle R.

    2015-01-01

    Lightning flashes are known to initiate in regions of strong electric fields inside thunderstorms, between layers of positively and negatively charged precipitation particles. For that reason, lightning inception is typically hidden from sight of camera systems used in research. Other technology such as lightning mapping systems based on radio waves can typically detect only some aspects of the lightning initiation process and subsequent development of positive and negative leader...

  20. Global Lightning Response to Forbush Decreases in Short-term

    Science.gov (United States)

    Li, H.; Wu, Q.; Wang, C.

    2017-12-01

    During the past three decades, particular scientific attention has been drawn to the potential link between solar activities and global climate change. How the sun modulates the climate has always been controversial. There are three relatively widely accepted mechanisms illustrating this process: the total solar irradiance (TSI), the solar ultraviolet radiation (SUR), and the space weather mechanisms. As for space weather mechanism, the sun influences the microphysical process in cloud by modulating the cosmic ray flux and thus changes the cloud cover, which finally affects the earth's radiation balance. Unfortunately, the lack of related observations and some opposite research results make this mechanism rather debatable. In order to provide possible evidence for space weather mechanism, we study the influence of Forbush decreases (FDs) of galactic cosmic ray on global lightning activities, which to some extent represents the basic process of cosmic ray-atmospheric coupling. We use the daily lightning counts from 1998 to 2014 observed by LIS sensor aboard the TRMM satellite. Considering the "diurnal distribution" (occurring more in the afternoon than in the morning) and the "seasonal distribution" (occurring more in summer than in winter) of lightning activities as well as the 49-day precession of TRMM satellite, the daily lightning counts show an intricate periodic fluctuation. We propose a 3-step approach - latitude zone limitation, orbit branch selection and local time normalization - to eliminate it. As for FDs, we select them by checking the hourly neutron counts variation of each month of 17 years obtained from the Oulu Cosmic Ray Station. During the selection, we choose the FDs which are "strong" (decrease more than 6%) and "standard" (strongly decrease in a few hours to one day and gradually recover in about one week) to diminish the meteorological influence and other possible disturbance. For both case study and temporal superposition of several cases

  1. LOFAR lightning imaging: Mapping lightning with nanosecond precision

    NARCIS (Netherlands)

    B.M. Hare; O. Scholten; A. Bonardi; S. Buitink; A. Corstanje; U. M. Ebert (Ute); H. Falcke; J.R. Hörandel (Jörg); H. Leijnse; P. Mitra; K. Mulrey; A. Nelles; J.P. Rachen; L. Rossetto; C. Rutjes (Casper); P. Schellart; S. Thoudam; T.N.G. Trinh (Gia); S. ter Veen (Sander); T. Winchen

    2018-01-01

    textabstractLightning mapping technology has proven instrumental in understanding lightning. In this work we present a pipeline that can use lightning observed by the LOw-Frequency ARray (LOFAR) radio telescope to construct a 3D map of the flash. We show that LOFAR has unparalleled precision, on the

  2. Laboratory demonstration of ball lightning

    Energy Technology Data Exchange (ETDEWEB)

    Egorov, Anton I; Stepanov, Sergei I; Shabanov, Gennadii D [B.P. Konstantinov St. Petersburg Institute of Nuclear Physics, Russian Academy of Sciences, Gatchina, Leningrad region, Rusian Federation (Russian Federation)

    2004-01-31

    A common laboratory facility for creating glowing flying plasmoids akin to a natural ball lightning, allowing a number of experiments to be performed to investigate the main properties of ball lightning, is described. (methodological notes)

  3. Emergency Preparedness and Response - Lightning

    Science.gov (United States)

    ... for Pet Owners Frequently Asked Questions Additional Information Lightning Language: English Español (Spanish) Recommend on Facebook Tweet ... you know what to do when you see lightning or when you hear thunder as a warning. ...

  4. Lightning Sensors for Observing, Tracking and Nowcasting Severe Weather

    Directory of Open Access Journals (Sweden)

    Colin Price

    2008-01-01

    Full Text Available Severe and extreme weather is a major natural hazard all over the world, oftenresulting in major natural disasters such as hail storms, tornados, wind storms, flash floods,forest fires and lightning damages. While precipitation, wind, hail, tornados, turbulence,etc. can only be observed at close distances, lightning activity in these damaging stormscan be monitored at all spatial scales, from local (using very high frequency [VHF]sensors, to regional (using very low frequency [VLF] sensors, and even global scales(using extremely low frequency [ELF] sensors. Using sensors that detect the radio wavesemitted by each lightning discharge, it is now possible to observe and track continuouslydistant thunderstorms using ground networks of sensors. In addition to the number oflightning discharges, these sensors can also provide information on lightningcharacteristics such as the ratio between intra-cloud and cloud-to-ground lightning, thepolarity of the lightning discharge, peak currents, charge removal, etc. It has been shownthat changes in some of these lightning characteristics during thunderstorms are oftenrelated to changes in the severity of the storms. In this paper different lightning observingsystems are described, and a few examples are provided showing how lightning may beused to monitor storm hazards around the globe, while also providing the possibility ofsupplying short term forecasts, called nowcasting.

  5. The Use of the North Alabama Lightning Mapping Array (NALMA) in the Real-Time Operational Warning Environment During the March 2nd, 2012 Severe Weather Outbreak in Northern Alabama

    Science.gov (United States)

    White, Kristopher; Carcione, Brian; Schultz, Christopher J.; Stano, Geoffrey T.; Carey, Lawrence D.

    2012-01-01

    The North Alabama Lightning Mapping Array (NALMA) is a three-dimensional very high frequency (VHF) detection network consisting of 11 sensors spread across north central Alabama and two sensors located in the Atlanta, Georgia region. The primary advantage of this network is that it detects total lightning, or the combination of both cloud-to-ground and intra-cloud lightning, instead of cloud-to-ground lightning alone. This helps to build a complete picture of storm evolution and development, and can serve as a proxy for storm updraft strength, particularly since intra-cloud lightning makes up the majority of all lightning in a typical thunderstorm. While the NALMA data do not directly indicate severe weather, they can indirectly indicate when a storm is strengthening (weakening) due to increases (decreases) in updraft strength, as the updraft is responsible for charging mechanisms within the storm. Data output are VHF radiation sources, which are produced during lightning breakdown processes. These sources are made into 2x2 km source density grids and are ported into the Advanced Weather Interactive Processing System (AWIPS) for National Weather Service (NWS) offices in Huntsville, AL, Nashville, TN, Morristown, TN, and Birmingham, AL, in near real-time. An increase in sources, or source densities, correlates to increased lightning activity and trends in updraft magnitude as long as the storm is within about 125 km of the center of the LMA network. Operationally, these data have been used at the Huntsville NWS office since early 2003 through a collaborative effort with NASA s Short-term Prediction Research and Transition (SPoRT) Center. Since then, total lightning observations have become an essential tool for forecasters during real-time warning operations. One of the operational advantages of the NALMA is the two-minute temporal resolution of the data. This provides forecasters with two to three updates during a typical volume scan of the WSR-88D radar.

  6. National athletic trainers' association position statement: lightning safety for athletics and recreation.

    Science.gov (United States)

    Walsh, K M; Bennett, B; Cooper, M A; Holle, R L; Kithil, R; López, R E

    2000-10-01

    To educate athletic trainers and others about the dangers of lightning, provide lightning-safety guidelines, define safe structures and locations, and advocate prehospital care for lightning-strike victims. Lightning may be the most frequently encountered severe-storm hazard endangering physically active people each year. Millions of lightning flashes strike the ground annually in the United States, causing nearly 100 deaths and 400 injuries. Three quarters of all lightning casualties occur between May and September, and nearly four fifths occur between 10:00 AM and 7:00 PM, which coincides with the hours for most athletic or recreational activities. Additionally, lightning casualties from sports and recreational activities have risen alarmingly in recent decades. The National Athletic Trainers' Association recommends a proactive approach to lightning safety, including the implementation of a lightning-safety policy that identifies safe locations for shelter from the lightning hazard. Further components of this policy are monitoring local weather forecasts, designating a weather watcher, and establishing a chain of command. Additionally, a flash-to-bang count of 30 seconds or more should be used as a minimal determinant of when to suspend activities. Waiting 30 minutes or longer after the last flash of lightning or sound of thunder is recommended before athletic or recreational activities are resumed. Lightning- safety strategies include avoiding shelter under trees, avoiding open fields and spaces, and suspending the use of land-line telephones during thunderstorms. Also outlined in this document are the prehospital care guidelines for triaging and treating lightning-strike victims. It is important to evaluate victims quickly for apnea, asystole, hypothermia, shock, fractures, and burns. Cardiopulmonary resuscitation is effective in resuscitating pulseless victims of lightning strike. Maintenance of cardiopulmonary resuscitation and first-aid certification should

  7. Response of total phenolic content and antioxidant activities of bush ...

    African Journals Online (AJOL)

    The positive health benefits associated with tea are made possible by the antioxidant activity of phenolic compounds present in tea. The total phenolic content and antioxidant activity of bush tea (Athrixia phylicoides DC.) and special tea (Monsonia burkeana) were studied. The extractions were done in triplicate using cold ...

  8. SECRET OF A BALL LIGHTNING

    Directory of Open Access Journals (Sweden)

    E.V. Savich

    2013-04-01

    Full Text Available A ball lightning is a natural phenomenon that occurs at a streak lightning stroke with its action by thermal and magnetic energy releasing around the streak lightning channel and transforming, in the end, the surrounding air into a steam cloud that transits into ferroelectric state under the magnetic field action.

  9. Lightning and severe thunderstorms in event management.

    Science.gov (United States)

    Walsh, Katie M

    2012-01-01

    There are a few national position stands/guidelines that address environmental conditions in athletics, yet they do not govern all outdoor sports. Extreme heat and cold, lightning, and severe wind can all be fatal, yet the majority of outdoor sports have no published guidelines addressing these conditions in relation to activity. Available research on extreme heat and cold conditions in athletics provides prevention strategies, to include acclimatization. Lightning and severe wind are two environmental conditions to which humans cannot accommodate, and they both can be deadly. There are strong positions on extreme heat/cold and lightning safety in athletics, but none affiliated with severe winds. Medical personnel involved in planning large outdoor sporting events must know of the presence of nationally published weather-related documents and apply them to their event. In addition, research needs to be expanded in the realm of establishing guidelines for safety to participants and spectators in severe wind conditions.

  10. Effect of total hip arthroplasty on recreational and sporting activity.

    Science.gov (United States)

    Chatterji, Urjit; Ashworth, Mark J; Lewis, Peter L; Dobson, Peter J

    2004-06-01

    Common concerns of patients undergoing total hip arthroplasty are whether they can continue with certain recreational and sporting activities or even commence new ones after the procedure. The present paper describes preoperative and postoperative activities, the numbers participating and the time to resume these activities. Between 1 and 2 years after total hip arthroplasty, 216 patients, who had undergone a total of 235 arthroplasties, were surveyed by postal questionnaire to ascertain how the arthroplasty had affected their recreational and sporting ability. Their preoperative and postoperative activity along with the time to resume was recorded. A general hip score and estimate of physical activity was also collected. The number of patients participating in sport increased from 188 preoperatively to 196 postoperatively. Patients stated that the surgery had a beneficial effect on their performance of sporting activities although the number of sporting events decreased. By multiplying individuals by the number of sports they participated in, there were 434 occurrences of sport preoperatively giving a mean for the group of 1.9 sports per patient. Postoperatively this had reduced to 382, giving a mean of 1.7. Five sports showed a significant change for individual patients from pre to postoperation. Those which showed an increase were exercise walking, where 38 patients (16.8%) who did not walk before surgery took up walking afterwards (P aqua aerobics, where 15 took up this activity postoperatively for the first time (P = 0.002). There were three sports which decreased significantly from pre to postoperation. They were, golf where 13 out of 39 (P = 0.005), tennis 13 out of 14 (P = 0.01) and jogging where six out of seven (P = 0.01) patients stopped participating. This study has shown that patients are adopting lower impact activities to participate in after total hip arthroplasty. The total number of patients performing a sport increases postoperatively but the

  11. The start of lightning: Evidence of bidirectional lightning initiation.

    Science.gov (United States)

    Montanyà, Joan; van der Velde, Oscar; Williams, Earle R

    2015-10-16

    Lightning flashes are known to initiate in regions of strong electric fields inside thunderstorms, between layers of positively and negatively charged precipitation particles. For that reason, lightning inception is typically hidden from sight of camera systems used in research. Other technology such as lightning mapping systems based on radio waves can typically detect only some aspects of the lightning initiation process and subsequent development of positive and negative leaders. We report here a serendipitous recording of bidirectional lightning initiation in virgin air under the cloud base at ~11,000 images per second, and the differences in characteristics of opposite polarity leader sections during the earliest stages of the discharge. This case reveals natural lightning initiation, propagation and a return stroke as in negative cloud-to-ground flashes, upon connection to another lightning channel - without any masking by cloud.

  12. Formation of ball lightning

    Energy Technology Data Exchange (ETDEWEB)

    Silberg, P.A. (2833 Lawton Drive, Amarillo, Texas (USA))

    A plasma continuum model for the formation of ball lightning is developed based on a substantial number of reports that the ball is often in the discharge column of a previous lightning stroke. The usual method of setting up the plasma equation for a one-component electron plasma is used. An approximate equation for the plasma is derived from the describing equation which is then solved exactly in terms of the Jacobi elliptic functions. The formation of the ball is based on a nonlinearity of the plasma equation which under certain circumstances permits the field to collapse into a small region. This collapse is interpreted to be ball lightning. The approximate equation derived for the plasma has the same form as a previous equation used to describe the formation of the fireball plasma.

  13. Lightning and precipitation produced by severe weather systems over Belém, Brazil

    Directory of Open Access Journals (Sweden)

    Wanda Maria do Nascimento Ribeiro

    2014-12-01

    Full Text Available CG Lightning flashes events monitored by a LDN of the Amazon Protection System, which included 12 LPATS IV VAISALA sensors distributed over eastern Amazonia, were analyzed during four severe rainstorm occurrences in Belem-PA-Brazil, in the 2006-2007 period. These selected case studies referred to rainfall events, which produced more than 25 mm/hour, or more than 40 mm/ 2 hours of precipitation rate totals, registered by a tipping bucket automatic high-resolution rain gauge, located at 1º 47' 53" S and 48º 30' 16" W. Centered at this location, a 30 ,10 and 5 km radius circles were drawn by means of a geographic information system, and the data from lightning occurrences within this larger area, were set apart for analysis. During these severe storms the CG lightning events, occurred almost randomly over the surrounding defined circle, previously covered by mesoscale convective systems, for all cases studied. This work also showed that the interaction between large-scale and mesoscale weather conditions have a major influence on the intensity of the storms studied cases. In addition to the enhancement of the lightning and precipitation rates, the electric activity within the larger circles can precede the rainfall at central point of the areas

  14. Lightning-Generated NO(x) Seen By OMI during NASA's TC-4 Experiment: First Results

    Science.gov (United States)

    Bucsela, Eric; Pickering, Kenneth E.; Huntemann, Tabitha; Cohen, Ronald; Perring, Anne; Gleason, James; Blakeslee, Richard; Navarro, Dylana Vargas; Segura, Ileana Mora; Hernandez, Alexia Pacheco; hide

    2009-01-01

    We present here case studies identifying upper-tropospheric NO2 produced in convective storms during NASA's Tropical Composition, Cloud and Climate Coupling Experiment (TCi)n July and August 2007. DC8 aircraft missions, flown from the mission base in Costa Rica, recorded in situ NO2 profiles near active storms and in relatively quiet areas. We combine these data with measurements from the Ozone Monitoring Instrument (OMI) on the Aura satellite to estimate the amount of NO2 produced by lightning (LN02) above background levels in the regions influenced by storms. In our analysis, improved off-line processing techniques are employed to minimize known artifacts in the OM1 data. Information on lightning flashes (primarily CG) observed by the surface network operated by the Instituto Costarricense de Electricidad are examined upwind of regions where OM1 indicates enhanced LNO2. Comparisons of the observed flash data with measurements by the TRMM/LIS satellite instrument are used to obtain the lightning detection efficiency for total flashes. Finally, using the NO/NO2 ratio estimated from DC-8 observations, we estimate the average NO(x) production per lightning flash for each case in this study. The magnitudes of the measured NO(x) enhancements are compared with those observed by the DC-8 and with similar OM1 measurements analyzed in mid-latitude experiments.

  15. Total antioxidant activity of yacon tubers cultivated in Brazil

    Directory of Open Access Journals (Sweden)

    Juciane Abreu Ribeiro Pereira

    Full Text Available ABSTRACT Yacon (Smallanthus sonchifolius is a tuberous root from the Andean region in the South America rich em water, fructooligosaccharides and phenolic compounds, some of which are natural antioxidants and may help prevent the deleterious action of free radicals in the body. The yacon has attracted much attention due to their potential health benefits to humans. In this study the levels of total phenolics, tannins, phenolic acids, and total antioxidant activity were measured in the peel and pulp of yacon tubers both in the fresh and flour forms. The flours of yacon presented higher concentrations of total phenolics and tannins, especially peel flour. The yacon pulp flour stood out as the main source of phenolic acids, mainly caffeic and chlorogenic acid. The total antioxidant activity assessed by DPPH (2,2-Diphenyl-1-picrylhydrazyl and ABTS (2,2′-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid assays was higher in the yacon peel flour. The total antioxidant activity was correlated with the total phenolic content and tannins by the DPPH and ABTS assays. These results suggest that yacon can be used as an alternative food source of phenolic compounds that help prevent degenerative processes caused by oxidative stress, especially in the flours form.

  16. First Cloud-to-Ground Lightning Timing Study

    Science.gov (United States)

    Huddleston, Lisa L.

    2013-01-01

    NASA's LSP, GSDO and other programs use the probability of cloud-to-ground (CG) lightning occurrence issued by the 45th Weather Squadron (45 WS) in their daily and weekly lightning probability forecasts. These organizations use this information when planning potentially hazardous outdoor activities, such as working with fuels, or rolling a vehicle to a launch pad, or whenever personnel will work outside and would be at-risk from lightning. These organizations would benefit greatly if the 45 WS could provide more accurate timing of the first CG lightning strike of the day. The Applied Meteorology Unit (AMU) has made significant improvements in forecasting the probability of lightning for the day, but forecasting the time of the first CG lightning with confidence has remained a challenge. To address this issue, the 45 WS requested the AMU to determine if flow regimes, wind speed categories, or a combination of the two could be used to forecast the timing of the first strike of the day in the Kennedy Space Center (KSC)/Cape Canaveral Air Force Station (CCAFS) lightning warning circles. The data was stratified by various sea breeze flow regimes and speed categories in the surface to 5,000-ft layer. The surface to 5,000-ft layer was selected since that is the layer the 45 WS uses to predict the behavior of sea breeze fronts, which are the dominant influence on the occurrence of first lightning in Florida during the warm season. Due to small data sample sizes after stratification, the AMU could not determine a statistical relationship between flow regimes or speed categories and the time of the first CG strike.. As expected, although the amount and timing of lightning activity varies by time of day based on the flow regimes and speed categories, there are extended tails of low lightning activity making it difficult to specify times when the threat of the first lightning flash can be avoided. However, the AMU developed a graphical user interface with input from the 45 WS

  17. Effect of total knee arthroplasty on recreational and sporting activity.

    Science.gov (United States)

    Chatterji, Urjit; Ashworth, Mark J; Lewis, Peter L; Dobson, Peter J

    2005-06-01

    Common concerns of patients undergoing total knee arthroplasty (TKA) are whether they can continue with certain recreational and sporting activities or even commence new ones after the procedure. The present study was designed to determine preoperative and postoperative activities, the numbers participating and the time to resume these activities. Between 1 and 2 years after TKA, patients who had undergone 144 arthroplasties, were surveyed by postal questionnaire to ascertain how the arthroplasty had affected their recreational and sporting ability. Their preoperative and postoperative activity along with the time to resume was recorded. The Oxford knee score and estimate of physical activity was also collected. Out of the 144 TKA performed, 122 participated in sport and recreational activity preoperatively and 108 participated postoperatively. Patients stated that the surgery had a beneficial effect on their performance of sporting and recreational activities although the number of sporting events decreased. By multiplying individuals by the number of activities they participated in, there were 254 occurrences of sport and recreational activities preoperatively giving a mean for the group of 1.76 sports/patient. Postoperatively this had reduced to 204, giving a mean of 1.41. Three activities showed a significant change for individual patients from pre- to postoperation. Those which showed an increase were exercise walking, where 19 patients (13.2%) who did not walk before surgery took up walking afterwards (P aqua aerobics, where five took up aqua aerobics postoperatively for the first time (P < 0.025). Golf was the only sport which had a significant fall in participation from pre- to postoperation, with 10 out of 19 golfers giving up (P < 0.025). The present study has shown that patients are adopting lower impact activities to participate in after TKA. The total number of patients performing a sport decreases postoperatively and the total amount of sport played

  18. Produce documents and media information. [on lightning

    Science.gov (United States)

    Alzmann, Melanie A.; Miller, G.A.

    1994-01-01

    Lightning data and information were collected from the United States, Germany, France, Brazil, China, and Australia for the dual purposes of compiling a global lightning data base and producing publications on the Marshall Space Flight Center's lightning program. Research covers the history of lightning, the characteristics of a storm, types of lightningdischarges, observations from airplanes and spacecraft, the future fole of planes and spacecraft in lightning studies, lightning detection networks, and the relationships between lightning and rainfall. Descriptions of the Optical Transient Dectector, the Lightning Imaging Sensor, and the Lightning Mapper Sensor are included.

  19. NASA storm hazards research in lightning strikes to aircraft

    Science.gov (United States)

    Fisher, B. D.; Brown, P. W.; Plumer, J. A.

    1985-01-01

    The lightning strike condition data gathered in the 1980-1984 period are presented, together with the lightning attachment point analysis for the NASA F-106B research aircraft are presented. The analysis of the experienced 637 direct lightning strikes shows that the highest strike rates (2.1 strikes/min and 13 strikes/penetration) occurred at altitudes between 38,000 and 40,000 ft. The regions of highest risk for an aircraft to experience a direct lightning strike were the areas of thunderstorms where the ambient temperature was colder than -40 C and where the relative turbulence and precipitation intensities were characterized as negligible to light. The presence and location of lightning, therefore, did not necessarily indicate the presence and location of hazardous precipitation and turbulence. The total onboard data show that the lightning attachment patterns on this aircraft fall into four general categories, although the 1984 data suggest that the entire surface of the F-106B may be susceptible to lightning attachment.

  20. rich extract on total polyphenols and antioxidant activity obtained by ...

    African Journals Online (AJOL)

    Z. Ghouila

    USTHB, Organic Functional Analysis Laboratory, 16111 Bab Ezzouar, Algiers, Algeria. 3. Department of General ... Keywords: Ahmeur Bouamer, extraction, grape seeds, total polyphenols, antioxidant activity. ... in food and pharmaceutical industry like BHA and BHT, which their undesirable effect on health was often ...

  1. Haemoglobin and Lung Total and Lysosomal Phosphatase Activity ...

    African Journals Online (AJOL)

    Comparisons were made of the effect of Benson & Hedges cigarette (filter-tipped) and Captain Black cigar (Non filter-tipped) smoke on rat plasma haemoglobin, carboxy-haemoglobin and nicotine levels, average body weight and daily feed intake, lung Total and lysosomal acid phosphatase activity. The results showed that ...

  2. Antioxidant activity study and total phenolic determination of leaf ...

    African Journals Online (AJOL)

    Methodology and results: This work was used to study the antioxidant activity of two extracts of Ximenia americana (Tallow wood) by the methods of ABTS•+ and DPPH using ascorbic acid as standard. It determined the rate of total phenolic in these extracts by the Folin-Ciocalteu (FC) method using Gallic acid as standard.

  3. Making Sense of Total VET Activity: An Initial Market Analysis

    Science.gov (United States)

    National Centre for Vocational Education Research (NCVER), 2016

    2016-01-01

    Following the successful first national publication of total vocational education and training (VET) activity and presentation of various informative data products, NCVER has continued to undertake further analysis of the submitted data. This paper is the first in a suite of the National Centre for Vocational Education Research (NCVER) authored…

  4. Antioxidant activity and total phenolic and flavonoid content of ...

    African Journals Online (AJOL)

    ajl yemi

    2011-12-19

    Dec 19, 2011 ... Full Length Research Paper. Antioxidant activity and total phenolic and flavonoid content of Astragalus squarrosus Bunge. Jinous Asgarpanah1*, Saeed Mohammadi Motamed2, Avishan Farzaneh1, Bahareh. Ghanizadeh1 and Simin Tomraee2. 1Young Researchers Club (YRC), Pharmaceutical Sciences ...

  5. Total Antioxidant Activity, and Hesperidin, Diosmin, Eriocitrin and ...

    African Journals Online (AJOL)

    Total Antioxidant Activity, and Hesperidin, Diosmin, Eriocitrin and Quercetin Contents of Various Lemon Juices. ... Conclusion: The developed method can also be applied to the determination of related extracts of orange cultivars as well as various extracts of medicinal plants. Keywords: Antioxidant, Flavonoid, Hesperidin, ...

  6. Importance of attenuating quadriceps activation deficits after total knee arthroplasty.

    Science.gov (United States)

    Thomas, Abbey C; Stevens-Lapsley, Jennifer E

    2012-04-01

    Total knee arthroplasty (TKA) is associated with persistent quadriceps dysfunction. Because quadriceps dysfunction impairs functional performance, minimizing quadriceps dysfunction by attenuating central activation deficits early after surgery may improve function later in life. Rehabilitation strategies incorporating neuromuscular electrical stimulation and early, aggressive quadriceps strengthening may prove beneficial. Furthermore, surgical approaches, such as minimally invasive TKA, may minimize postoperative quadriceps dysfunction.

  7. Antioxidant activity and total phenolics of some mangroves in ...

    African Journals Online (AJOL)

    SERVER

    2008-03-18

    Mar 18, 2008 ... Deepanjan Banerjee, Shrabana Chakrabarti, Alok K. Hazra, Shivaji Banerjee, Jharna Ray and. Biswapati .... 765 nm was measured (Ultrospec 2000 UV-visible spectrophoto- meter ... Table 1. Total phenolic content, reducing power and antiradical activity of different parts of mangrove plants in Sundarbans.

  8. Cytotoxicity, Total Phenolic Contents and Antioxidant Activity of the ...

    African Journals Online (AJOL)

    The leaves of Annona muricata were extracted using ethanol and the extracts were evaluated for cytotoxicity using Brine Shrimp Lethality Assay, total phenolic content (TPC) and antioxidant activity using DPPH radical scavenging assay. The crude extract showed 73.33 % mortality at 1000 μg/mL concentration and its ...

  9. Climate analysis of lightning launch commit criteria for Kennedy Space Center and Cape Canaveral Air Force Station

    OpenAIRE

    Muller, Eric C.

    2010-01-01

    Approved for public release; distribution is unlimited We have conducted climate analyses of natural lightning activity at Kennedy Space Center and Cape Canaveral Air Force Station (KSC/CCAFS). These analyses were conducted to improve forecasts of lightning related hazards for, and the planning of, space vehicle launches at KSC/CCAFS. If a space vehicle is hit by lightning during launch, the vehicle and payload may sustain irreparable damage. Lightning-based rules for conducting launch a...

  10. Optimizing Precipitation Thresholds for Best Correlation Between Dry Lightning and Wildfires

    Science.gov (United States)

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

    2018-03-01

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

  11. Global distribution of winter lightning: a threat to wind turbines and aircraft

    Science.gov (United States)

    Montanyà, Joan; Fabró, Ferran; van der Velde, Oscar; March, Víctor; Rolfe Williams, Earle; Pineda, Nicolau; Romero, David; Solà, Glòria; Freijo, Modesto

    2016-06-01

    Lightning is one of the major threats to multi-megawatt wind turbines and a concern for modern aircraft due to the use of lightweight composite materials. Both wind turbines and aircraft can initiate lightning, and very favorable conditions for lightning initiation occur in winter thunderstorms. Moreover, winter thunderstorms are characterized by a relatively high production of very energetic lightning. This paper reviews the different types of lightning interactions and summarizes the well-known winter thunderstorm areas. Until now comprehensive maps of global distribution of winter lightning prevalence to be used for risk assessment have been unavailable. In this paper we present the global winter lightning activity for a period of 5 years. Using lightning location data and meteorological re-analysis data, six maps are created: annual winter lightning stroke density, seasonal variation of the winter lightning and the annual number of winter thunderstorm days. In the Northern Hemisphere, the maps confirmed Japan to be one of the most active regions but other areas such as the Mediterranean and the USA are active as well. In the Southern Hemisphere, Uruguay and surrounding area, the southwestern Indian Ocean and the Tasman Sea experience the highest activity. The maps provided here can be used in the development of a risk assessment.

  12. Lightning Imaging with LOFAR

    Directory of Open Access Journals (Sweden)

    Scholten Olaf

    2017-01-01

    Full Text Available We show that LOFAR can be used as a lightning mapping array with a resolution that is orders of magnitude better than existing arrays. In addition the polarization of the radiation can be used to track the direction of the stepping discharges.

  13. Protecting Electronic Equipment in Composite Structures against Lightning

    OpenAIRE

    Blaj, M.A.

    2015-01-01

    Damage resulting from an interaction with lightning current in a military naval vessel, especially in a conflict zone and at the time of a conflict, which leads to the incapacitation of vital activities on the ship, is unacceptable. Because many potential conflict zones are in littoral areas, and because of the increase in lightning activity, both now and expected in the years to come, the provision of protection for naval vessels sailing in those waters should be a high priority. The fact th...

  14. Lightning and radar observations of hurricane Rita landfall

    Energy Technology Data Exchange (ETDEWEB)

    Henderson, Bradley G [Los Alamos National Laboratory; Suszcynsky, David M [Los Alamos National Laboratory; Hamlin, Timothy E [Los Alamos National Laboratory; Jeffery, C A [Los Alamos National Laboratory; Wiens, Kyle C [TEXAS TECH U.; Orville, R E [TEXAS A& M

    2009-01-01

    Los Alamos National Laboratory (LANL) owns and operates an array of Very-Low Frequency (VLF) sensors that measure the Radio-Frequency (RF) waveforms emitted by Cloud-to-Ground (CG) and InCloud (IC) lightning. This array, the Los Alamos Sferic Array (LASA), has approximately 15 sensors concentrated in the Great Plains and Florida, which detect electric field changes in a bandwidth from 200 Hz to 500 kHz (Smith et al., 2002). Recently, LANL has begun development of a new dual-band RF sensor array that includes the Very-High Frequency (VHF) band as well as the VLF. Whereas VLF lightning emissions can be used to deduce physical parameters such as lightning type and peak current, VHF emissions can be used to perform precise 3d mapping of individual radiation sources, which can number in the thousands for a typical CG flash. These new dual-band sensors will be used to monitor lightning activity in hurricanes in an effort to better predict intensification cycles. Although the new LANL dual-band array is not yet operational, we have begun initial work utilizing both VLF and VHF lightning data to monitor hurricane evolution. In this paper, we present the temporal evolution of Rita's landfall using VLF and VHF lightning data, and also WSR-88D radar. At landfall, Rita's northern eyewall experienced strong updrafts and significant lightning activity that appear to mark a transition between oceanic hurricane dynamics and continental thunderstorm dynamics. In section 2, we give a brief overview of Hurricane Rita, including its development as a hurricane and its lightning history. In the following section, we present WSR-88D data of Rita's landfall, including reflectivity images and temporal variation. In section 4, we present both VHF and VLF lightning data, overplotted on radar reflectivity images. Finally, we discuss our observations, including a comparison to previous studies and a brief conclusion.

  15. LM lightning protection and evolutions for larger wind turbine rotor blades

    Energy Technology Data Exchange (ETDEWEB)

    Mortensen, I. [LM Glasfiber Group, Lunderskov (Denmark)

    2005-07-01

    Over 2000 thunder storms are active throughout the world at any given moment, producing approximately 100 flashes of lightning per second. Non-conducting wind turbine blades without conducting components are often struck by lightning and suffer major damage. Statistics have shown that lightning causes 4 to 8 faults per 100 turbines per year in northern Europe, and that 7 to 10 per cent of all lightning damages involve wind turbine blades, which are the most expensive components to repair. There is also an increased risk of inboard puncture for lightning strikes of lower currents. Various lightning protection systems were presented in this paper, as well as optimization methods for different types of wind turbine blades. Multi-receptors, drain receptors, conductive cables and diverter strips were evaluated. Testing procedures for lightning protection components were reviewed. An outline of the Hige voltage test was presented. It was noted that pollution promotes the capture capabilities of wind turbine blades. Extensive high-voltage impact tests have shown that the semi-conductive carbon fibre is struck by lightning as often as the actual lightning receptors. Details of the LM DiverterStrip were presented. The strip captures the lightning strike and guides the way to the receptor. The strip is low maintenance and designed to last for 20 years, with a minimal influence on air flow. In addition, the current travelling in an ionized path above the segments of the LM strip makes a smooth transfer to the receptor. A recent year-long field tests has shown good results, without any wear or lightning damage to the strips. It was concluded that lightning protection reduces insurance costs, and that standard lightning protection systems used for fibre glass blades do not provide sufficient lightning protection for carbon fibre blades. refs., tabs., figs.

  16. Science of Ball Lightning (Fire Ball)

    Science.gov (United States)

    Ohtsuki, Yoshi-Hiko

    1989-08-01

    The Table of Contents for the full book PDF is as follows: * Organizing Committee * Preface * Ball Lightning -- The Continuing Challenge * Hungarian Ball Lightning Observations in 1987 * Nature of Ball Lightning in Japan * Phenomenological and Psychological Analysis of 150 Austrian Ball Lightning Reports * Physical Problems and Physical Properties of Ball Lightning * Statistical Analysis of the Ball Lightning Properties * A Fluid-Dynamical Model for Ball Lightning and Bead Lightning * The Lifetime of Hill's Vortex * Electrical and Radiative Properties of Ball Lightning * The Candle Flame as a Model of Ball Lightning * A Model for Ball Lightning * The High-Temperature Physico-Chemical Processes in the Lightning Storm Atmosphere (A Physico-Chemical Model of Ball Lightning) * New Approach to Ball Lightning * A Calculation of Electric Field of Ball Lightning * The Physical Explanation to the UFO over Xinjiang, Northern West China * Electric Reconnection, Critical Ionization Velocity, Ponderomotive Force, and Their Applications to Triggered and Ball Lightning * The PLASMAK™ Configuration and Ball Lightning * Experimental Research on Ball Lightning * Performance of High-Voltage Test Facility Designed for Investigation of Ball Lightning * List of Participants

  17. A Spatial and Temporal Analysis of Upward Triggered Lightning

    Science.gov (United States)

    Ballweber, A. J.

    2013-12-01

    Alana Ballweber, John H. Helsdon Jr., and Tom A. Warner South Dakota School of Mines and Technology Ten tall communication towers lining the ridge in Rapid City, South Dakota provide a unique opportunity to study the phenomenon of lightning-triggered upward lightning. The Upward Lightning Triggering Study (UPLIGHTS), seeks to determine if upward positive leaders are triggered from these towers by: (1) the approach of horizontally propagating negative stepped leaders associated with either intracloud development or following a positive cloud-to-ground (+CG) return stroke, and/or (2) a +CG return stroke as it propagates through a previously formed leader network near the towers. As part of the UPLIGHTS research, two separate lightning mapping devices were used to aid in a 3D re-creation of the triggering flash, a 3D digital interferometer and a Lightning Mapping Array. Through the use of these two devices, we present findings founded on the analysis of data collected from these assets during the 2013 storm season. Specifically, we quantify the spatial and temporal relationship of the triggering flash leader activity relative to the tall objects when upward leaders develop and when upward leaders fail to develop. Furthermore, the lightning mapping devices were correlated with high-speed optical and electrical field observations to provide a further insight as to why certain flashes trigger upward lightning from tall structures and others do not.

  18. Total phenolics and antioxidant activity of five medicinal plant

    International Nuclear Information System (INIS)

    Sousa, Cleyton Marcos de M.; Silva, Hilris Rocha e; Vieira-Junior, Gerardo Magela; Ayres, Mariane Cruz C.; Costa, Charllyton Luis S. da; Araajo, Delton Servulo; Cavalcante, Luis Carlos D.; Barros, Elcio Daniel S.; Araujo, Paulo Breitner de M.; Brandao, Marcela S.; Chaves, Mariana H.

    2007-01-01

    This paper describes total phenolics content and antioxidant activity in the ethanolic extract of leaves, bark and roots of five medicinal plants: Terminalia brasiliensis Camb., Terminalia fagifolia Mart. and Zucc., Copernicia cerifera (Miller) H.E. Moore, Cenostigma macrophyllum Tul. var. acuminata Teles Freire and Qualea grandiflora Mart. The total phenolics content of the plant extracts, determined by the Folin-Ciocalteu method, varied from 250.0 ±8,2 to 763,63 ±13.03 mg of gallic acid equivalent/g dry EtOH extract. The antioxidant activity of extracts was evaluated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay system. Extract of bark from T. brasiliensis, the most active, with an EC 50 value of 27.59 ± 0.82 μg/mL, was comparable to rutin (EC 50 = 27.80 ± 1.38) and gallic acid (EC 50 = 24.27 ± 0.31), used as positive controls. The relationship between total phenolic content and antioxidant activity was positive and significant for T. brasiliensis, C. macrophyllum and C. cerifera. (author)

  19. Characterizing the Relationships Among Lightning and Storm Parameters: Lightning as a Proxy Variable

    Science.gov (United States)

    Goodman, S. J.; Raghavan, R.; William, E.; Weber, M.; Boldi, B.; Matlin, A.; Wolfson, M.; Hodanish, S.; Sharp. D.

    1997-01-01

    We have gained important insights from prior studies that have suggested relationships between lightning and storm growth, decay, convective rain flux, vertical distribution of storm mass and echo volume in the region, and storm energetics. A study was initiated in the Summer of 1996 to determine how total (in-cloud plus ground) lightning observations might provide added knowledge to the forecaster in the determination and identification of severe thunderstorms and weather hazards in real-time. The Melbourne Weather Office was selected as a primary site to conduct this study because Melbourne is the only site in the world with continuous and open access to total lightning (LDAR) data and a Doppler (WSR-88D) radar. A Lightning Imaging Sensor Data Applications Demonstration (LISDAD) system was integrated into the forecaster's workstation during the Summer 1996 to allow the forecaster to interact in real-time with the multi-sensor data being displayed. LISDAD currently ingests LDAR data, the cloud-to-ground National Lightning Detection Network (NLDN) data, and the Melbourne radar data in f real-time. The interactive features provide the duty forecaster the ability to perform quick diagnostics on storm cells of interest. Upon selection of a storm cell, a pop-up box appears displaying the time-history of various storm parameters (e.g., maximum radar reflectivity, height of maximum reflectivity, echo-top height, NLDN and LDAR lightning flash rates, storm-based vertically integrated liquid water content). This product is archived to aid on detailed post-analysis.

  20. Lightning hazard region over the maritime continent observed from satellite and climate change threat

    Science.gov (United States)

    Ilhamsyah, Y.; Koesmaryono, Y.; Hidayat, R.; Murjaya, J.; Nurjaya, I. W.; Rizwan

    2017-02-01

    Climate change would lead to such hydrometeorological disaster as: flash-flood, landslide, hailstone, lightning, and twister become more likely to happen in the future. In terms of lightning event, one research question arise of where lightning would be mostly to strike over the Maritime Continent (MC)?. The objective of the research is to investigate region with high-density of lightning activity over MC by mapping climatological features of lightning flashes derived from onboard NASA-TRMM Satellite, i.e. Optical Transient Detector/Lightning Imaging Sensor (OTD/LIS). Based on data retrieved since 1995-2013, it is seasonally observed that during transition season March to May, region with high vulnerability of lightning flashes cover the entire Sumatra Island, the Malacca Strait, and Peninsular Malaysia as well as Java Island. High-frequent of lightning activity over the Malacca Strait is unique since it is the only sea-region in the world where lightning flashes are denser. As previously mentioned that strong lightning activity over the strait is driven by mesoscale convective system of Sumatra Squalls due to convergences of land breeze between Sumatra and Peninsular Malaysia. Lightning activity over the strait is continuously observed throughout season despite the intensity reduced. Java Island, most populated island, receive high-density of lightning flashes during rainy season (December to February) but small part in the northwestern of Java Island, e.g., Bogor and surrounding areas, the density of lightning flashes are high throughout season. Northern and southern parts of Kalimantan and Central part of Sulawesi are also prone to lightning activity particularly during transition season March to May and September to November. In the eastern part of MC, Papua receive denser lightning flashes during September to November. It is found that lightning activity are mostly concentrated over land instead of ocean which is in accordance with diurnal convective

  1. Nowcasting lightning using weather radar and a new ice mass estimator

    Science.gov (United States)

    Ruzanski, Evan; Chandrasekar, Venkatachalam

    2017-04-01

    Lightning nowcasts are important for a number of applications and the range, resolution, and volumetric nature of weather radar observations are favorable for nowcasting lightning. Ice aloft, a key component in the atmospheric electrification process, can be estimated using weather radar data. This presentation describes a new model for estimating ice mass aloft and a method of nowcasting lightning activity using weather radar data. Previous research used a cell-based approach to lightning nowcasting and verification, where storm cells were first identified, lightning activity was associated with a particular cell, but lead times and lightning locations were not specified in the forecast. The new method described in this presentation takes a grid-based approach to lightning nowcasting and verification. This approach leverages spatial correlations and potentially complex interactions between storm cells and atmospheric scales. It also makes specific nowcasts in space and time. The new weather radar-based ice mass estimator uses a novel dynamic numerical optimization approach to reframe a simplified bulk microphysical model into a completely data-driven model. Preliminary results show that using this new model significantly improves nowcasts versus using the traditional weather radar-based ice mass estimator or lightning flash-rate density directly for nowcasting first-flash lightning occurrence. A novel verification approach is also described and used to assess this first-flash lightning nowcasting performance.

  2. Eddy Current Model of Ball Lightning

    OpenAIRE

    Shelton, J. D.

    2011-01-01

    Eddy Current Model of Ball Lightning Calculations show that high-energy ball lightning may consist of a ball of plasma containing a large circular electric current arising as an eddy current generated by lightning. Synthetic ball lightning might serve as a method of plasma confinement for purposes of nuclear fusion. In this paper, three articles concerning ball lightning and the related phenomenon of large ball lightning are combined to provide insight into this rarely glimpsed occurrence.

  3. Seasonal variations in the lightning diurnal cycle and implications for the global electric circuit

    Science.gov (United States)

    Blakeslee, Richard J.; Mach, Douglas M.; Bateman, Monte G.; Bailey, Jeffrey C.

    2014-01-01

    Data obtained from the Optical Transient Detector and the Lightning Imaging Sensor satellites (70° and 35° inclination low earth orbits, respectively) are used to statistically determine the number of flashes in the seasonal diurnal cycle as a function of local and universal time. These data include corrections for detection efficiency and instrument view time. They are further subdivided by season, land versus ocean, and other spatial (e.g., continents) and temporal (e.g., time of peak diurnal amplitude) categories. These statistics are then combined with analyses of high altitude aircraft observations of electrified clouds to produce the seasonal diurnal variation in the global electric circuit. Continental results display strong diurnal variation, with a lightning peak in the late afternoon and a minimum in late morning. In geographical regions dominated by large mesoscale convective systems, the peak in the diurnal curve shifts toward late evening or early morning hours. The maximum seasonal diurnal flash rate occurs in June-August, corresponding to the Northern Hemisphere summer, while the minimum occurs in December-February. Summer lightning dominates over winter activity and springtime lightning dominates over fall activity at most continental locations. Oceanic lightning exhibits minimal diurnal variation, but morning hours are slightly enhanced over afternoon. As was found earlier, for the annual diurnal variation, using basic assumptions about the mean storm currents as a function of flash rate and location (i.e., land/ocean), our seasonal estimates of the current in the global electric circuit provide an excellent match with independent measurements of the seasonal Carnegie curve diurnal variations. The maximum (minimum) total mean current of 2.4 kA (1.7 kA) is found during Northern Hemisphere summer (winter). Land thunderstorms supply about one half (52%) of the total global current. Ocean thunderstorms contribute about one third (31%) and the non-lightning

  4. The Distribution of Lightning Channel Lengths in Northern Alabama Thunderstorms

    Science.gov (United States)

    Peterson, H. S.; Koshak, W. J.

    2010-01-01

    Lightning is well known to be a major source of tropospheric NOx, and in most cases is the dominant natural source (Huntreiser et al 1998, Jourdain and Hauglustaine 2001). Production of NOx by a segment of a lightning channel is a function of channel segment energy density and channel segment altitude. A first estimate of NOx production by a lightning flash can be found by multiplying production per segment [typically 104 J/m; Hill (1979)] by the total length of the flash s channel. The purpose of this study is to determine average channel length for lightning flashes near NALMA in 2008, and to compare average channel length of ground flashes to the average channel length of cloud flashes.

  5. Antioxidant activity, total phenolic, and total flavonoid of extracts from stems of Jasminum nervosum Lour

    Directory of Open Access Journals (Sweden)

    Wei, Xiangyong

    2011-06-01

    Full Text Available Guangxi traditional Chinese Medical University Universidad de Medicina Tradicional China de Guangxi This study evaluated the antioxidant activities of the extracts of Jasminum nervosum Lour. stems along with the effects of different extract solvents on total phenolics (TP, total flavonoids (TF, and antioxidant potential. The antioxidant activity of the extracts was assessed using the following methods: DPPH, ABTS+ both free radicals scavenging assays, and reducing assays. TP and TF were detected by spectrophotometric and HPLC methods. In former methods, the highest amount of TP content was ethy lacetate extract (EAE, expressed as gallic acid equivalents. The greatest TF content was in the n-butanol extract (BE, expressed as lutin equivalents. No significant difference was observed in the TP/TF content between these two extracts. The antioxidant activity and TP/TF content of three extracts seemed to follow the same trend. This implied that there is a good correlation between antioxidant activities and TP/TF content. But in HPLC methods, EAE contained the highest content of lutin and gallic acid, which decreased in the same order of EAE > BE > PE, the rank order of TP/TF content of EAE and BE were different according to antioxidant ability. The overall results showed that the EAE and BE were richer in phenolics and flavonoids than petroleum ether extract (PE, and may represent a good source of antioxidants.Este estudio evaluó las actividades antioxidantes de extractos de tallos de Jasminum nervosum Lour., y el efecto de diferentes disolventes de extracción en los fenoles totales (TP y flavonoides totales (TF, y su potencial antioxidante. La actividad antioxidante de los extractos fue evaluada usando los siguientes métodos: DPPH, ABTS+ y ensayos reductores. TP y TF fueron detectados por métodos espectroscópicos y por HPLC. Con el primer método, el contenido más alto de TP se obtuvo en el extracto con acetato de etilo (EAE, expresado como

  6. The active human gut microbiota differs from the total microbiota.

    Directory of Open Access Journals (Sweden)

    Francesc Peris-Bondia

    Full Text Available The human gut microbiota is considered one of the most fascinating reservoirs of microbial diversity hosting between 400 to 1000 bacterial species distributed among nine phyla with Firmicutes, Bacteroidetes and Actinobacteria representing around 75% of the diversity. One of the most intriguing issues relates to understanding which microbial groups are active players in the maintenance of the microbiota homeostasis.Here, we describe the diversity of active microbial fractions compared with the whole community from raw human fecal samples. We studied four healthy volunteers by 16S rDNA gene pyrosequencing. The fractions were obtained by cell sorting based on bacterial RNA concentration. Bacterial families were observed to appear or disappear on applying a cell sorting method in which flow cytometry was used to evaluate the active cells by pyronin-Y staining of RNA. This method was able to detect active bacteria, indicating that the active players differed from that observed in raw fecal material. Generally, observations showed that in the active fractions, the number of reads related to Bacteroidetes decreased whereas several families from Clostridiales (Firmicutes were more highly represented. Moreover, a huge number of families appeared as part of the active fraction when cell sorting was applied, indicating reads that are simply statistically hidden by the total reads.

  7. Sports participation outside school in total physical activity of children.

    Science.gov (United States)

    Saar, Meeli; Jürimäe, Toivo

    2007-10-01

    This study of associations of sports participation with perceived and actual physical fitness, and total physical activity for 525 10- to 17-yr.-old boys and girls in groups of 10-11-yr. (56 boys and 64 girls), 12-13-yr. (68 boys and 68 girls), 14-15-yr. (70 boys and 71 girls), and 16-17-yr. (68 boys and 60 girls) was based on the Physical Activity Index derived from a questionnaire by Telama, Leskinen, and Young, and self-perceived endurance, strength, flexibility, and body composition. Questions about satisfaction with physical activity, participation in organized physical activity and competitions, or watching competitions were asked. Two EUROFIT tests were used, the 20-m endurance shuttle-run and sit-and-reach, plus the sum of 9 skinfold thicknesses. Children who participated in organized physical activity and in competitions had a higher Physical Activity Index. Passive watching of competitions was not related to children's physical activity or their perceived or measured motor abilities.

  8. OLS ANALOG DERIVED LIGHTNING V11

    Data.gov (United States)

    National Aeronautics and Space Administration — The OLS Analog Derived Lightning dataset consists of global lightning signatures from the Defense Meteorological Satellite Program (DMSP) Operational Linescan System...

  9. Lightning protection of PV systems

    OpenAIRE

    Pons, Enrico; Tommasini, Riccardo

    2013-01-01

    Lightning strikes can affect photovoltaic (PV) generators and their installations, involving also the inverter's electronics. It is therefore necessary to evaluate the risk connected to lightning strikes in order to adopt the correct protective measures for the system. The Standard IEC (EN) 62305-2 reports the procedures for the risk calculation and for the choice of proper lightning protection systems. Usually the technical guidelines suggest protecting with SPDs (surge protective devices) b...

  10. Antioxidant Activities of Total Pigment Extract from Blackberries

    Directory of Open Access Journals (Sweden)

    Jiechao Liu

    2005-01-01

    Full Text Available Total pigment has been extracted from blackberries and its antioxidant activity against lipid peroxidation and scavenging capacities towards superoxide anion radicals, hydroxyl radicals and nitrite in different in vitro systems have been investigated. The total pigment extract from blackberries (TPEB exhibited strong antioxidant activity against lipid peroxidation in a linoleic acid model system and scavenging capacities towards superoxide anion radicals, generated by a pyrogallol autoxidation system or by an illuminating riboflavin system, hydroxyl radicals generated by Fenton reaction, and nitrite. Furthermore, the antioxidant activities were correlated with the concentrations of the TPEB. In the test concentration range, the maximum inhibition percentage against linoleic acid peroxidation was 98.32 % after one week’s incubation, and the maximum scavenging percentages for the free radicals and nitrite inhibition in the above reactive systems reached 90.48, 96.48, 93.58 and 98.94 %, respectively. The TPEB is a natural, edible colorant with excellent antioxidant activities and health benefits and it seems to be applicable in both healthy food and medicine.

  11. Lightning Sensors for Observing, Tracking and Nowcasting Severe Weather

    OpenAIRE

    Colin Price

    2008-01-01

    Severe and extreme weather is a major natural hazard all over the world, often resulting in major natural disasters such as hail storms, tornados, wind storms, flash floods, forest fires and lightning damages. While precipitation, wind, hail, tornados, turbulence, etc. can only be observed at close distances, lightning activity in these damaging storms can be monitored at all spatial scales, from local (using very high frequency [VHF] sensors), to regional (using very low frequency [VLF] sens...

  12. Global Lightning Climatology from the Tropical Rainfall Measuring Mission (TRMM), Lightning Imaging Sensor (LIS) and the Optical Transient Detector (OTD)

    Science.gov (United States)

    Cecil, Daniel J.; Buechler, Dennis E.; Blakeslee, Richard J.

    2015-01-01

    The Tropical Rainfall Measuring Mission (TRMM) Lightning Imaging Sensor (LIS) has been collecting observations of total lightning in the global tropics and subtropics (roughly 38 deg S - 38 deg N) since December 1997. A similar instrument, the Optical Transient Detector, operated from 1995-2000 on another low earth orbit satellite that also saw high latitudes. Lightning data from these instruments have been used to create gridded climatologies and time series of lightning flash rate. These include a 0.5 deg resolution global annual climatology, and lower resolution products describing the annual cycle and the diurnal cycle. These products are updated annually. Results from the update through 2013 will be shown at the conference. The gridded products are publicly available for download. Descriptions of how each product can be used will be discussed, including strengths, weaknesses, and caveats about the smoothing and sampling used in various products.

  13. Performance assessment of Beijing Lightning Network (BLNET) and comparison with other lightning location networks across Beijing

    Science.gov (United States)

    Srivastava, Abhay; Tian, Ye; Qie, Xiushu; Wang, Dongfang; Sun, Zhuling; Yuan, Shanfeng; Wang, Yu; Chen, Zhixiong; Xu, Wenjing; Zhang, Hongbo; Jiang, Rubin; Su, Debin

    2017-11-01

    The performances of Beijing Lightning Network (BLNET) operated in Beijing-Tianjin-Hebei urban cluster area have been evaluated in terms of detection efficiency and relative location accuracy. A self-reference method has been used to show the detection efficiency of BLNET, for which fast antenna waveforms have been manually examined. Based on the fast antenna verification, the average detection efficiency of BLNET is 97.4% for intracloud (IC) flashes, 73.9% for cloud-to-ground (CG) flashes and 93.2% for the total flashes. Result suggests the CG detection of regional dense network is highly precise when the thunderstorm passes over the network; however it changes day to day when the thunderstorms are outside the network. Further, the CG stroke data from three different lightning location networks across Beijing are compared. The relative detection efficiency of World Wide Lightning Location Network (WWLLN) and Chinese Meteorology Administration - Lightning Detection Network (CMA-LDN, also known as ADTD) are approximately 12.4% (16.8%) and 36.5% (49.4%), respectively, comparing with fast antenna (BLNET). The location of BLNET is in middle, while WWLLN and CMA-LDN average locations are southeast and northwest, respectively. Finally, the IC pulses and CG return stroke pulses have been compared with the S-band Doppler radar. This type of study is useful to know the approximate situation in a region and improve the performance of lightning location networks in the absence of ground truth. Two lightning flashes occurred on tower in the coverage of BLNET show that the horizontal location error was 52.9 m and 250 m, respectively.

  14. Viscometric method for assaying of total endodepolymerase activity of pectinases.

    Science.gov (United States)

    Gusakov, A V; Markov, A V; Grishutin, S G; Semenova, M V; Kondratyeva, E G; Sinitsyn, A P

    2002-06-01

    An improved method for assaying of the total endodepolymerase activity of pectinases has been developed. The method is based on the determination of the viscosity of a citrus pectin solution in the presence of the enzyme using an Ostwald viscometer. The depolymerizing activity of different pectinases can be detected including polygalacturonase, polymethylgalacturonase, pectin lyase, and pectate lyase. One unit of the endodepolymerase activity corresponds to the activity resulting in 50% decrease in the relative viscosity of 0.5% citrus pectin solution for 5 min at 40 degrees C and the appropriate pH. Depending on the pH-optima of the enzymes, two modifications of the method are described: 1) for acid pectinases at pH 5.0, and 2) for neutral (mildly alkaline) pectinases at pH 8.0. The modifications differed in the control and in the calculation of the activity. Six enzyme preparations were used to demonstrate the applicability of the method. The parameter used for the calculation of the enzymatic activity was directly proportional to the enzyme concentration (the dependence was linear in the range of at least 10-fold change in the enzyme concentration). The relative error of the method did not exceed 10%.

  15. Climate change. Projected increase in lightning strikes in the United States due to global warming.

    Science.gov (United States)

    Romps, David M; Seeley, Jacob T; Vollaro, David; Molinari, John

    2014-11-14

    Lightning plays an important role in atmospheric chemistry and in the initiation of wildfires, but the impact of global warming on lightning rates is poorly constrained. Here we propose that the lightning flash rate is proportional to the convective available potential energy (CAPE) times the precipitation rate. Using observations, the product of CAPE and precipitation explains 77% of the variance in the time series of total cloud-to-ground lightning flashes over the contiguous United States (CONUS). Storms convert CAPE times precipitated water mass to discharged lightning energy with an efficiency of 1%. When this proxy is applied to 11 climate models, CONUS lightning strikes are predicted to increase 12 ± 5% per degree Celsius of global warming and about 50% over this century. Copyright © 2014, American Association for the Advancement of Science.

  16. Monitoring of lightning discharge

    International Nuclear Information System (INIS)

    Grigor'ev, V.A.

    2001-01-01

    The paper presents a brief description of a lightning discharge recording system developed at the NPO 'Monitoring Techniques' under the direction of V.M. Moskolenko (Moscow). The system provides information about dangerous environmental occurrences such as tornados and hurricanes, making the forecast of extreme situations possible, especially in the areas of dangerous industries and objects. The created automatic system can be useful in solving the tasks relating to nuclear test monitoring. (author)

  17. Ball Lightning Investigations

    Science.gov (United States)

    Bychkov, V. L.; Nikitin, A. I.; Dijkhuis, G. C.

    Ball lightning (BL) researches' review and theoretical models of three different authors are presented. The general review covers investigations from 1838 until the present day, and includes a discussion on observation data, experimental modeling, and theoretical approaches. Section 6.1 is written by Bychkov and Nikitin; authors of the sections 6.2, 6.3 and 6.4 are, respectively, Bychkov, Nikitin and Dijkhuis.

  18. A Probabilistic, Facility-Centric Approach to Lightning Strike Location

    Science.gov (United States)

    Huddleston, Lisa L.; Roeder, William p.; Merceret, Francis J.

    2012-01-01

    A new probabilistic facility-centric approach to lightning strike location has been developed. This process uses the bivariate Gaussian distribution of probability density provided by the current lightning location error ellipse for the most likely location of a lightning stroke and integrates it to determine the probability that the stroke is inside any specified radius of any location, even if that location is not centered on or even with the location error ellipse. This technique is adapted from a method of calculating the probability of debris collisionith spacecraft. Such a technique is important in spaceport processing activities because it allows engineers to quantify the risk of induced current damage to critical electronics due to nearby lightning strokes. This technique was tested extensively and is now in use by space launch organizations at Kennedy Space Center and Cape Canaveral Air Force Station. Future applications could include forensic meteorology.

  19. Assessing the relationship between high lightning events and storm mode in northern and central Alabama

    Science.gov (United States)

    Willis, Morgan Terry

    Lightning is a dangerous and deadly hazard, yet it is often underestimated by the public and excluded from severe weather watches and warnings used by the National Weather Service. Previous studies have analyzed the relationship of lightning and storm intensity in relation to severe weather, but none have analyzed this relationship across all storm modes in an area including Northern and Central Alabama. This study attempts to assess the relationship between cloud-to-ground (CG) lightning and storm mode in storm events which occurred on lightning hazard days in Northern and Central Alabama during the years of 2007 to 2011. Storm variables for analysis included lightning flash rate, aspect ratio, total convective area above 20 dBZ, maximum convective area above 40 dBZ, and percent maximum convective area. Results show that lightning flash rates vary by season and storm mode. PCA and Cluster Analysis identified a total of 5 clusters of varying lightning flash rate and convective intensity. The storm mode events include non-summer linear, an anomalous MCS associated with a triple point frontal outflow boundary, summer airmass, non-seasonal weak, and summer MCS/MCC. Information obtained during this thesis has the potential to aid forecasters and emergency managers in Northern and Central Alabama by associating lightning flash rates with storm mode characteristics observed on lightning hazard days.

  20. Cell-tracking with lightning data from LINET

    Directory of Open Access Journals (Sweden)

    H. D. Betz

    2008-07-01

    Full Text Available A new lightning detection network (LINET has been developed at the University of Munich, which locates and reports both cloud discharges and cloud-to-ground strokes with high accuracy. The network started operation in May 2006; since then lightning data for Europe are being delivered to many scientific groups, and to the German Weather Service (DWD on an operational basis (powered by nowcast GmbH, Germany. Using about 90 lightning sensors in 17 countries, an area from longitude 10° W–25° E to latitude 35° N–65° N is covered. Further expansion is in the planning stage with the aim to attain higher efficiency for Mediterranean storms. The total lightning capability, not readily available otherwise in large areas, is particularly helpful because it can provide useful information about the development of severe weather and strong storm cells. A cell-tracking module has been developed that allows the investigation of lightning parameters for specific convective cells. Present efforts are devoted to the question for what kind of storms and to what extent lightning-based cell tracking allows improved nowcasting. Numerous case studies have been carried out and typical examples will be presented.

  1. TOTAL ANTIOXIDANT ACTIVITY OF SOME BASIDIOMYCETES STRAINS IN GROWTH DYNAMIC

    Directory of Open Access Journals (Sweden)

    O. V. Fedotov

    2016-08-01

    Full Text Available The work is devoted to the study of total antioxidant activity (AOA in the growth dynamics of basidiomycetes strains in their periodic surface cultivation on glucose-peptone medium. Subjects of research are mycelium and culture filtrate (CF from 57 strains, 5 of which are belong to 5 types of Polyporales order, and 52 of which are belong to the 7 types of Agaricales order. In order to study the dynamics of growth used method for determining the weight of absolutely dry biomass accumulation (ADB. Total AOA of mycological material was evaluated by inhibition of lipid peroxidation products accumulation intensity in the model oxidation reaction of Tween-80 by air oxygen. It was found that the most productive in terms of the accumulation of ADB are strains F. velutipes F-610 and P. eryngii P-er. Lowest values of ADB accumulation recorded for strains P. ostreatus P-14 and P-192 and P. citrinopileatus P sіtr. Were selected the most productive strains of Basidiomycetes for the level of total AOA in mycelium and CF. There are strains P. eryngii P-er, P. citrinopileatus P sіtr, P. ostreatus P-035, F. hepatica Fh-08, A. cylindracea 960, P. ostreatus P-081, P-082, P-087, P. citrinopileatus P sіtr. Has not been established the dependence between the growth and the antioxidant activity of the 9- and 12-day fungal cultures. Selected producers of natural antioxidants may be used as biological agents in biotechnology.

  2. Upward lightning attachment analysis on wind turbines and correlated current parameters

    DEFF Research Database (Denmark)

    Vogel, Stephan; Ishii, M.; Saito, M.

    2017-01-01

    . The dataset of video recordings and current measurements originates from the Japanese New Energy and Industrial Technology Development Organization Furthermore (NEDO) measurement campaign (2008 – 2013) which documented lightning incidences on wind turbines mainly during the winter season at the Sea of Japan.......This work provides insight in the attachment characteristics of upward initiated lightning discharges to wind turbines and their possible consequences for the lightning protection of wind turbine blades. All discharges were recorded at the Japanese coast of the Sea of Japan which is known...... for intense upward lightning activity. 172 video recordings of lightning discharges on rotating wind turbines are analysed and attachment angle, detachment angle, and the resulting angular displacement were determined. A classification between self-initiated and other-triggered upward lightning events...

  3. Lightning injuries during snowy conditions

    OpenAIRE

    Cherington, M.; Breed, D. W.; Yarnell, P. R.; Smith, W. E.

    1998-01-01

    Skiers and other snow sports enthusiasts can become lightning casualties. Two such accidents are reported, one being fatal. There are fewer warning signals of impending lightning strikes in winter-like conditions. However, outdoor activists should be aware of at least two suspicious clues: the appearance of convective clouds, and the presence of graupel (snow pellets) during precipitation. 






  4. Lightning injuries during snowy conditions.

    Science.gov (United States)

    Cherington, M; Breed, D W; Yarnell, P R; Smith, W E

    1998-12-01

    Skiers and other snow sports enthusiasts can become lightning casualties. Two such accidents are reported, one being fatal. There are fewer warning signals of impending lightning strikes in winter-like conditions. However, outdoor activists should be aware of at least two suspicious clues: the appearance of convective clouds, and the presence of graupel (snow pellets) during precipitation.

  5. Ionospheric effects of thunderstorms and lightning

    Energy Technology Data Exchange (ETDEWEB)

    Lay, Erin H. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-02-03

    Tropospheric thunderstorms have been reported to disturb the lower ionosphere (~65-90 km) by convective atmospheric gravity waves and by electromagnetic field changes produced by lightning discharges. However, due to the low electron density in the lower ionosphere, active probing of its electron distribution is difficult, and the various perturbative effects are poorly understood. Recently, we have demonstrated that by using remotely-detected ?me waveforms of lightning radio signals it is possible to probe the lower ionosphere and its fluctuations in a spatially and temporally-resolved manner. Here we report evidence of gravity wave effects on the lower ionosphere originating from the thunderstorm. We also report variations in the nighttime ionosphere atop a small thunderstorm and associate the variations with the storm’s electrical activity. Finally, we present a data analysis technique to map ionospheric acoustic waves near thunderstorms.

  6. 14 CFR 25.581 - Lightning protection.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Lightning protection. 25.581 Section 25.581... STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Lightning Protection § 25.581 Lightning protection. (a) The airplane must be protected against catastrophic effects from lightning. (b) For metallic...

  7. Total antiradical activity in male castrated piglets blood: reference values

    Directory of Open Access Journals (Sweden)

    Carlo Corino

    2010-01-01

    Full Text Available Blood samples from 146 male castrated piglets in the range of 10-47kg body weight were collected from the same farm and analysed for total antiradical activity in order to determine reference intervals. Data were tested for normality and then submitted to reference limit evaluation. The reference values found in piglets, expressed as half-hemolysis time (59.34 – 93.60 and 43.94 – 66.90 minutes for blood and red blood cell, respectively, are lower than those found in humans; further studies are needed to extend reference values study to female and to animals of different weight classes and different genetic type.

  8. Lightning activity and radar observations of the multicell thunderstorm system passing over Swider Observatory (Poland) on 19 July 2015 and its dynamic and electric charge structure obtained from the WRF_ELEC model

    Science.gov (United States)

    Kubicki, Marek; Konarski, Jerzy; Gajda, Wojciech; Barański, Piotr; Guzikowski, Jakub; Kryza, Maciej

    2017-04-01

    In this work we present preliminary results on the thunderstorm event at IG PAS Swider Geophysical Observatory (52.12°N, 21.25°E, geomagnetic latitude 50.5°N, near Warsaw, Poland) on 19 July 2015. The storm was caused by the abrasion of the warm front that stretched almost latitudinaly and cold front moving from the west to the east. Warm continental-tropical arrived at southern and eastern part of the country and the rest was covered by cool polar-maritime airmass. The storm had the squall-line character of approximately 100 km length and consisted of several cells, and the height of the cumulonimbus (Cb) cloud base was 1 km and top was 14 km, as inferred from the analysis of CAPPI (Constant Altitude Plan Position Indicator), CMAX (Column Maximum Display), MLVCUT (Multiple-Line Vertical Cut) radar map products from POLRAD observations at Institute of Meteorology and Water Management - National Research Institute (IMWM-NRI), Legionowo station. In our paper we have discussed the obtained results of the post-time analysis of lightning activity and radar observations of the extended multicells thunderstorm system passing over IG PAS Swider Geophysical Observatory, on 19 July 2015 together with its dynamic and electric charge structure obtained from the WRF_ELEC model. We have used the archive data from the Polish National Lightning Location and Detection System PERUN (provided by IMWM-NRI) together with radar data obtained from the Doppler meteorological radar METEOR 1500C at Legionowo. Additionally, during the approach, passing over and moving away phase of the thunderstorm system, we have gathered the simultaneous and continuous recordings of E-field, the electric conductivity of air and the independent supplementary reference lightning detections delivered by the Swider measuring station of the Local Lightning Detection Network (LLDN) operated in Warsaw region. These data have given us a new possibility to acquire many valuable information about the

  9. Automated thunderstorm tracking: utilization of three-dimensional lightning and radar data

    Directory of Open Access Journals (Sweden)

    V. K. Meyer

    2013-05-01

    Full Text Available This paper presents a new hybrid method for automated thunderstorm observation by tracking and monitoring of electrically charged cells (ec-TRAM. The developed algorithm combines information about intense ground precipitation derived from low-level radar-reflectivity scans with three-dimensionally resolved lightning data, which are provided by the European VLF/LF lightning detection network LINET. Based on the already existing automated radar tracker rad-TRAM (Kober and Tafferner, 2009, the new method li-TRAM identifies and tracks electrically active regions in thunderclouds using lightning data only. The algorithm ec-TRAM uses the output of the two autonomously operating routines rad-TRAM and li-TRAM in order to assess, track, and monitor a more comprehensive picture of thunderstorms. The main motivation of this work is to assess the benefit of three-dimensionally resolved total lightning (TL information for thunderstorm tracking and monitoring. The focus is laid on the temporal development whereby TL is characterized by an effective in-cloud (IC and cloud-to-ground (CG event discrimination. It is found that the algorithms li-TRAM and ec-TRAM are both feasible methods for thunderstorm monitoring with potential for nowcasting. The tracking performance of li-TRAM turns out to be comparable to that of rad-TRAM, a result that strongly encourages utilization of lightning data as independent data source for thunderstorm tracking. It is found that lightning data allow an accurate and close monitoring of storm regions with intense internal dynamics as soon as convection induces electrical activity. A case study shows that the current short-term storm dynamics are clearly reflected in the amount of strokes, change of stroke rates and IC/CG ratio. The hybrid method ec-TRAM outperforms rad-TRAM and li-TRAM regarding reliability and continuous assessment of storm tracks especially in more complexly developing storms, where the use of discharge information

  10. Nearshore regional behavior of lightning interaction with wind turbines

    Directory of Open Access Journals (Sweden)

    Gilbert A. Malinga

    2016-01-01

    Full Text Available The severity of lightning strikes on offshore wind turbines built along coastal and nearshore regions can pose safety concerns that are often overlooked. In this research study the behavior of electrical discharges for wind turbines that might be located in the nearshore regions along the East Coast of China and Sea of Japan were characterized using a physics-based model that accounted for a total of eleven different geometrical and lightning parameters. Utilizing the electrical potential field predicted using this model it was then possible to estimate the frequency of lightning strikes and the distribution of electrical loads utilizing established semi-empirical relationships and available data. The total number of annual lightning strikes on an offshore wind turbine was found to vary with hub elevation, extent of cloud cover, season and geographical location. The annual lightning strike rate on a wind turbine along the nearshore region on the Sea of Japan during the winter season was shown to be moderately larger compared to the lightning strike frequency on a turbine structure on the East Coast of China. Short duration electrical discharges, represented using marginal probability functions, were found to vary with season and geographical location, exhibiting trends consistent with the distribution of the electrical peak current. It was demonstrated that electrical discharges of moderately long duration typically occur in the winter months on the East Coast of China and the summer season along the Sea of Japan. In contrast, severe electrical discharges are typical of summer thunderstorms on the East Coast of China and winter frontal storm systems along the West Coast of Japan. The electrical charge and specific energy dissipated during lightning discharges on an offshore wind turbine was found to vary stochastically, with severe electrical discharges corresponding to large electrical currents of long duration.

  11. Decomposing Gender Disparity in Total Physical Activity among Iranian Adults

    Directory of Open Access Journals (Sweden)

    Ebrahim Rahimi

    2017-10-01

    Full Text Available OBJECTIVES While gender differences in physical activity (PA have been reported, their origin is not well understood. The present study aimed to identify factors contributing to this disparity. METHODS This was a population-based cross-sectional study based on the 2011 surveillance of risk factors of non-communicable diseases that was conducted among Iranian adults. Multi-staged sampling was performed to obtain the required study sample. The primary outcome was gender differences in the prevalence of sufficient physical activity (SPA. Total physical activity (TPA was calculated as metabolic equivalents (MET per minute during a typical week, as recommended by the World Health Organization. On this basis, achieving 600 MET-min/wk or more was defined as SPA. The nonlinear Blinder-Oaxaca decomposition technique was used to explain the disparity. RESULTS The predicted gap was 19.50%. About one-third of the gap was due to differences in the level of observable covariates. Among them, work status contributed the most (29.61%. A substantial portion of the gap remained unexplained by such differences, of which about 40.41% was related to unobservable variables. The differential effects of standard of living, ethnicity, and smoking status made the largest contribution, accounting for 37.36, 35.47, and 28.50%, respectively. CONCLUSIONS Interventions to reduce the gender gap in PA should focus on increasing TPA among housewives and women with chronic diseases, as well as those with a higher standard of living. In addition, it is essential to explore the impact of ethnicity and smoking status on women’s TPA in order to promote health.

  12. Physical and observable characteristics of cloud-to-ground lightning over the Pearl River Delta region of South China

    Science.gov (United States)

    Liu, Yonglin; Chan, L. Y.; Lin, Qinhao; Feng, Wanxing; Bi, Xinhui; Chen, Jiahong; Tao, Hantao; Wang, Xinming; Chen, Duohong; Sheng, Guoying; Fu, Jiamo

    2014-05-01

    Cloud-to-ground (CG) lightning characteristic parameters deduced from the lightning location system (LLS) for five differing microenvironmental areas relative to megacity, city, municipal town, hilly suburban area, and mountainous rural area conditions were examined in our 2009-2011 Pearl River Delta (PRD) study. Our LLS data analysis showed that there were high variation of lightning characteristics and phenomenal changes among these areas. As a supplement to the usual study of physical characteristics, an observation-based methodology had been developed to study the lightning behavior, while the respective thunderstorms were traversing through these observation areas. Special features and phenomenal changes related to the lightning characteristic parameters, such as observable lightning stroke days (OLSDs) and observable lightning stroke frequency and density for an OLSD, were also addressed. Microenvironmental variation due to change in topography, degree of urbanization, urban effect, and thunderstorm strength was found to affect the spatial distribution of lightning stroke and the severity of lightning activities over the observation areas. This approach increases our understanding of lightning in subtropical China. It also tells us more about the behavior of lightning while the thunderstorm traverses through an observation area. This information is lacking in previous studies.

  13. Chasing Lightning: Sferics, Tweeks and Whistlers

    Science.gov (United States)

    Webb, P. A.; Franzen, K.; Garcia, L.; Schou, P.; Rous, P.

    2008-12-01

    We all know what lightning looks like during a thunderstorm, but the visible flash we see is only part of the story. This is because lightning also generates light with other frequencies that we cannot perceive with our eyes, but which are just as real as visible light. Unlike the visible light from lightning, these other frequencies can carry the lightning's energy hundreds or thousands of miles across the surface of the Earth in the form of special signals called "tweeks" and "sferics". Some of these emissions can even travel tens of thousands of miles out into space before returning to the Earth as "whistlers". The INSPIRE Project, Inc is a non-profit scientific and educational corporation whose beginning mission was to bring the excitement of observing these very low frequency (VLF) natural radio waves emissions from lightning to high school students. Since 1989, INSPIRE has provided specially designed radio receiver kits to over 2,600 participants around the world to make observations of signals in the VLF frequency range. Many of these participants are using the VLF data they collect in very creative projects that include fiction, music and art exhibitions. During the Fall 2008 semester, the first INSPIRE based university-level course was taught at University of Maryland Baltimore County (UMBC) as part of its First-Year Seminar (FYS) series. The FYS classes are limited to 20 first-year students per class and are designed to create an active-learning environment that encourages student participation and discussion that might not otherwise occur in larger first-year classes. This presentation will cover the experiences gained from using the INSPIRE kits as the basis of a university course. This will include the lecture material that covers the basic physics of lightning, thunderstorms and the Earth's atmosphere, as well as the electronics required to understand the basic workings of the VLF kit. It will also cover the students assembly of the kit in an

  14. Lightning and Radar Observations of the 29 May 2004 Tornadic HP Supercell during TELEX

    Science.gov (United States)

    Macgorman, D. R.; Kuhlman, K. M.

    2006-12-01

    On 29 May 2004, a tornadic heavy-precipitation (HP) supercell storm moved through central Oklahoma and through the Thunderstorm Electrification and Lightning Experiment (TELEX) domain. Three dimensional lightning location data from the Oklahoma Lightning Mapping Array (OK-LMA) depict the evolution of the storm, including convective surges, overshooting tops, and the formation and dissipation of lightning weak holes. In addition to the OK-LMA, the storm was also observed by two C-band mobile radars (SMART-R radars) providing three-minute volume scans and by the KOUN polarimetric S-band radar. Analysis of a lightning weak hole showed that it was co-located horizontally with a core of strong updrafts and with a bounded weak echo region. The majority of the cloud-to-ground lightning detected in the storm by the National Lightning Detection Network lowered negative charge to ground. However, during genesis of the strongest tornado, the dominant polarity of ground flashes near the reflectivity core of the storm evolved to positive. Also at approximately this time, negative ground strikes began occurring under the anvil, tens of kilometers from the reflectivity core, as lightning activity surged roughly 100 km into the anvil. Observations from these platforms provide insight into HP supercell evolution and structure and into relationships of lightning with other properties of the storm.

  15. A statistical scheme to forecast the daily lightning threat over southern Africa using the Unified Model

    Science.gov (United States)

    Gijben, Morné; Dyson, Liesl L.; Loots, Mattheus T.

    2017-09-01

    Cloud-to-ground lightning data from the Southern Africa Lightning Detection Network and numerical weather prediction model parameters from the Unified Model are used to develop a lightning threat index (LTI) for South Africa. The aim is to predict lightning for austral summer days (September to February) by means of a statistical approach. The austral summer months are divided into spring and summer seasons and analysed separately. Stepwise logistic regression techniques are used to select the most appropriate model parameters to predict lightning. These parameters are then utilized in a rare-event logistic regression analysis to produce equations for the LTI that predicts the probability of the occurrence of lightning. Results show that LTI forecasts have a high sensitivity and specificity for spring and summer. The LTI is less reliable during spring, since it over-forecasts the occurrence of lightning. However, during summer, the LTI forecast is reliable, only slightly over-forecasting lightning activity. The LTI produces sharp forecasts during spring and summer. These results show that the LTI will be useful early in the morning in areas where lightning can be expected during the day.

  16. Unsolved Mystery of Ball Lightning

    Science.gov (United States)

    Bychkov, V. L.

    Ball lightning is an unusual phenomenon always drawing attention of people. There are still questions about its origination, features, interaction with environment, and phenomena related to it. On a way of studying this phenomenon, there are a lot of difficulties, the basic of them is insufficiency of authentic, scientific data. The chapter sets as the purpose to interest the reader in the problem, to describe conditions of ball lightning occurrence, theories, and its hypotheses explanation, to include readers in a circle of experimental searches in creation of a ball lightning and its analogues, and to describe fascination of a problem and difficulty of its solution.

  17. Experience in the management of disused lightning rods containing 241Am in a research institute in Brazil.

    Science.gov (United States)

    Vicente, Roberto; Potiens, Ademar; Sakata, Solange; Dellamano, José

    2013-11-01

    Radioactive lightning rods (RLR) were manufactured and installed in Brazil for almost two decades, before they were prohibited in 1989. Structures protected by this type of lightning preventers included residential buildings, schools, commercial and industrial facilities, among others. It is estimated that about 3.4 TBq of 241Am were used by manufacturers, and a total of 75,000 pieces with a mean activity of about 46 MBq were in the market. While only a fraction of the total has been recovered, the almost twenty thousand pieces already collected at the Nuclear and Energy Research Institute (IPEN) had their sources successfully separated from the remaining recyclable metal scrap and are now encapsulated in lead containers for final disposal.

  18. Electrical and Hydrometeor Structure of Thunderstorms that produce Upward Lightning

    Science.gov (United States)

    dos Santos Souza, J. C.; Albrecht, R. I.; Lang, T. J.; Saba, M. M.; Warner, T. A.; Schumann, C.

    2017-12-01

    Upward lightning (UL) flashes at tall structures have been reported to be initiated by in-cloud branching of a parent positive cloud-to-ground (CG) or intracloud (IC) lightning during the decaying stages of thunderstorms, and associated with stratiform precipitation. This in-cloud branching of the parent CG lightning into lower layers of the stratiform precipitation, as well as other situational modes of UL triggering, are indicative of a lower charge center. The objective of this study is to determine the hydrometeor characteristics of thunderstorms that produce UL, especially at the lower layers of the stratiform region where the bidirectional leader of the parent CG or IC lightning propagates through. We investigated 17 thunderstorms that produced 56 UL flashes in São Paulo, SP, Brazil and 10 thunderstorms (27 UL) from the UPLIGHTS field experiment in Rapid City, SD, USA. We used polarimetric radar data and 3D lighting mapping or the combination of total (i.e., intracloud and cloud-to-ground) and cloud-to-ground lightning strokes data. The Hydrometeor Identification for the thunderstorms of this study consider the information from polarimetric variables ZH, ZDR, KDP and RHOHV to infer radar echoes into rain (light, medium, heavy), hail, dry snow, wet snow, ice crystals, graupel and rain-hail mixtures. Charge structure is inferred by the 3D very-high-frequency (VHF) Lightning Mapping Array by monitoring lightning propagation closely in time and space and constructing vertical histograms of VHF source density. The results of this research project are important to increase the understanding of the phenomenon, the storm evolution and the predictability of UL.

  19. Delayed gamma radiation from lightning induced nuclear reactions

    Science.gov (United States)

    Greenfield, M. B.; Sakuma, K.; Ikeda, Y.; Kubo, K.

    2004-03-01

    An increase in atmospheric gamma radiation observed with NaI and Ge detectors positioned about 15 m above ground was observed following natural lightning near Tokyo, Japan [1]. Background subtracted gamma ray rates GRR following numerous lightning strokes observed since 2001 persisted for a few hours and subsequently decayed with a half-life of about 50 minutes. Using a 3x3 Ge detector, with 2 KeV resolution, positioned about 2 m from one of the NaI detectors increases in GRR were observed minutes after the onset of lightning with a delayed 50 min exponential decay. Although most of the increase in activity occured at less than a few 100 KeV, on July 11, 2003 a 1267 +/-2 KeV line was observed. Although the statistics of this event were poor, the appearance of this line with an exponential decay of 50 min half-life suggests the possibility that it may be due to 39Cl (1267 MeV; half-life = 55.5 min) via the 40Ar(gamma,p)39Cl, 40Ar(p,2p)39Cl and/or 40Ar(n,d)39Cl reactions. Observations of > 10 MeV gamma rays observed in NaI detectors within 10s of meters from and coincident with rocket-triggered lightning at the International Center for Lightning Research and Testing suggest that charged particles accelerated in intense electric fields associated with lightning give rise to photons with sufficient energy to initiate nuclear reactions [2]. Further work to explain the cause of this anomalous activity is underway using natural and triggered lightning. 1. M. B. Greenfield et al., Journal of Applied Physics 93 no. 3 (2003) pp 1839-184. 2. J. R. Dwyer et al., Science 299, (2003), pp 694-697 and recent communications

  20. Simulating lightning into the RAMS model: two case studies

    Science.gov (United States)

    Federico, Stefano; Avolio, Elenio; Petracca, Marco; Panegrossi, Giulia; Dietrich, Stefano

    2013-04-01

    In this paper we show the results of the implementation of a tailored version of a methodology already presented in the bibliography to simulate flashes into the Regional Atmospheric Modeling System (RAMS). The method gives the flash rate for each thundercloud, which is detected by a labelling algorithm applied to the output of RAMS. The flash rate is computed by assuming a plane capacitor model, which is charged by the non-inductive graupel-ice charge separation mechanism and is discharged by lightning. The method explicitly considers the charging zone and uses the geometry of the graupel field to redistribute the flashes. An important feature of the method is that it gives the position and time of occurrence of each flash, allowing for a detailed and comprehensive display of the lightning activity during the simulation period. The method is applied to two case studies occurred over the Lazio Region, in central Italy. Simulations are compared with the lightning detected by the LINET network. The cases refer to a thunderstorm characterized by an intense lightning activity (up to 2800 flashes per hour over the Lazio Region), and a moderate thunderstorm (up to 1600 flashes per hour over the same domain). The results show that the model is able to catch the main features of both storms and their relative differences. This feature is promising because the method is computationally fast and gives a tool to the forecaster to predict the lightning threat. Nevertheless there are errors in timing (O(3h)) and positioning (O(100km)) of the convection, which mirrors in timing and position errors of the lightning distribution. These model shortcomings presently limit the use of the lightning forecast; nevertheless the method can take advantages of future development of the model physics, initialization techniques, and ensemble forecast. A useful application of the method in an ensemble forecast is already suggested.

  1. Lightning Jump Algorithm and Relation to Thunderstorm Cell Tracking, GLM Proxy and Other Meteorological Measurements

    Science.gov (United States)

    Schultz, Christopher J.; Carey, Lawrence D.; Cecil, Daniel J.; Bateman, Monte

    2012-01-01

    The lightning jump algorithm has a robust history in correlating upward trends in lightning to severe and hazardous weather occurrence. The algorithm uses the correlation between the physical principles that govern an updraft's ability to produce microphysical and kinematic conditions conducive for electrification and its role in the development of severe weather conditions. Recent work has demonstrated that the lightning jump algorithm concept holds significant promise in the operational realm, aiding in the identification of thunderstorms that have potential to produce severe or hazardous weather. However, a large amount of work still needs to be completed in spite of these positive results. The total lightning jump algorithm is not a stand-alone concept that can be used independent of other meteorological measurements, parameters, and techniques. For example, the algorithm is highly dependent upon thunderstorm tracking to build lightning histories on convective cells. Current tracking methods show that thunderstorm cell tracking is most reliable and cell histories are most accurate when radar information is incorporated with lightning data. In the absence of radar data, the cell tracking is a bit less reliable but the value added by the lightning information is much greater. For optimal application, the algorithm should be integrated with other measurements that assess storm scale properties (e.g., satellite, radar). Therefore, the recent focus of this research effort has been assessing the lightning jump's relation to thunderstorm tracking, meteorological parameters, and its potential uses in operational meteorology. Furthermore, the algorithm must be tailored for the optically-based GOES-R Geostationary Lightning Mapper (GLM), as what has been observed using Very High Frequency Lightning Mapping Array (VHF LMA) measurements will not exactly translate to what will be observed by GLM due to resolution and other instrument differences. Herein, we present some of

  2. 2016 T Division Lightning Talks

    Energy Technology Data Exchange (ETDEWEB)

    Ramsey, Marilyn Leann [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Adams, Luke Clyde [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Ferre, Gregoire Robing [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Grantcharov, Vesselin [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Iaroshenko, Oleksandr [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Krishnapriyan, Aditi [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Kurtakoti, Prajvala Kishore [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Le Thien, Minh Quan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Lim, Jonathan Ng [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Low, Thaddeus Song En [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Lystrom, Levi Aaron [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Ma, Xiaoyu [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Nguyen, Hong T. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Pogue, Sabine Silvia [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Orandle, Zoe Ann [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Reisner, Andrew Ray [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Revard, Benjamin Charles [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Roy, Julien [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Sandor, Csanad [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Slavkova, Kalina Polet [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Weichman, Kathleen Joy [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Wu, Fei [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Yang, Yang [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division

    2016-11-29

    These are the slides for all of the 2016 T Division lightning talks. There are 350 pages worth of slides from different presentations, all of which cover different topics within the theoretical division at Los Alamos National Laboratory (LANL).

  3. 2017 T Division Lightning Talks

    Energy Technology Data Exchange (ETDEWEB)

    Ramsey, Marilyn Leann [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Abeywardhana, Jayalath AMM [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Adams, Colin Mackenzie [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Adams, Luke Clyde [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Carter, Austin Lewis [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ducru, Pablo Philippe [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Duignan, Thomas John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Gifford, Brendan Joel [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hills, Benjamin Hale [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hoffman, Kentaro Jack [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Khair, Adnan Ibne [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Kochanski, Kelly Anne Pribble [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ledwith, Patrick John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Leveillee, Joshua Anthony [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lewis, Sina Genevieve [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ma, Xiaoyu [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Merians, Hugh Drake [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Moore, Bryan Alexander [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Nijjar, Parmeet Kaur [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Oles, Vladyslav [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Olszewski, Maciej W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Philipbar, Brad Montgomery [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Reisner, Andrew Ray [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Roberts, David Benjamin [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Rufa, Dominic Antonio [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Sifain, Andrew E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Smith, Justin Steven [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Smith, Lauren Taylor Wisbey [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Svolos, Lampros [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Thibault, Joshua Ryan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ushijima-Mwesigwa, Hayato Montezuma [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Weaver, Claire Marie [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Witzen, Wyatt Andrew [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Zentgraf, Sabine Silvia [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Alred, John Michael [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-10-06

    All members of the T Division Community, students, staff members, group leaders, division management, and other interested individuals are invited to come and support the following student(s) as they present their Lightning Talks.

  4. Acoustic localization of triggered lightning

    Science.gov (United States)

    Arechiga, Rene O.; Johnson, Jeffrey B.; Edens, Harald E.; Thomas, Ronald J.; Rison, William

    2011-05-01

    We use acoustic (3.3-500 Hz) arrays to locate local (thunder produced by triggered lightning in the Magdalena Mountains of central New Mexico. The locations of the thunder sources are determined by the array back azimuth and the elapsed time since discharge of the lightning flash. We compare the acoustic source locations with those obtained by the Lightning Mapping Array (LMA) from Langmuir Laboratory, which is capable of accurately locating the lightning channels. To estimate the location accuracy of the acoustic array we performed Monte Carlo simulations and measured the distance (nearest neighbors) between acoustic and LMA sources. For close sources (6 km) the error increases to 800 m for the nearest neighbors and 650 m for the Monte Carlo analysis. This work shows that thunder sources can be accurately located using acoustic signals.

  5. How much locomotive activity is needed for an active physical activity level: analysis of total step counts

    OpenAIRE

    Ohkawara, Kazunori; Ishikawa-Takata, Kazuko; Park, Jong Hoon; Tabata, Izumi; Tanaka, Shigeho

    2011-01-01

    Abstract Background Although physical activity recommendations for public health have focused on locomotive activity such as walking and running, it is uncertain how much these activities contribute to overall physical activity level (PAL). The purpose of the present study was to determine the contribution of locomotive activity to PAL using total step counts measured in a calorimeter study. Methods PAL, calculated as total energy expenditure divided by basal metabolic rate, was evaluated in ...

  6. Ground Optical Lightning Detector (GOLD)

    Science.gov (United States)

    Jackson, John, Jr.; Simmons, David

    A photometer developed to characterize lightning from the ground is discussed. The detector and the electronic signal processing and data storage systems are presented along with field data measured by the system. The discussion will include improvements that will be incorporated to enhance the measurement of lightning and the data storage capability to record for many days without human involvement. Finally, the calibration of the GOLD system is presented.

  7. Method to determine the activity concentration and total activity of radioactive waste

    International Nuclear Information System (INIS)

    Angeles C, A.

    2001-02-01

    A characteristic system of radioactive waste is described to determine the concentration of radionuclides activity and the total activity of bundles of radioactive waste. The system this integrated by three subsystems: - Elevator of drums. - Electromechanics. - Gamma spectroscopy. In the system it is analyzed waste of issuing gamma specifically, and this designed for materials of relative low density and it analyzes materials of cylindrical recipients

  8. Industrial accidents triggered by lightning.

    Science.gov (United States)

    Renni, Elisabetta; Krausmann, Elisabeth; Cozzani, Valerio

    2010-12-15

    Natural disasters can cause major accidents in chemical facilities where they can lead to the release of hazardous materials which in turn can result in fires, explosions or toxic dispersion. Lightning strikes are the most frequent cause of major accidents triggered by natural events. In order to contribute towards the development of a quantitative approach for assessing lightning risk at industrial facilities, lightning-triggered accident case histories were retrieved from the major industrial accident databases and analysed to extract information on types of vulnerable equipment, failure dynamics and damage states, as well as on the final consequences of the event. The most vulnerable category of equipment is storage tanks. Lightning damage is incurred by immediate ignition, electrical and electronic systems failure or structural damage with subsequent release. Toxic releases and tank fires tend to be the most common scenarios associated with lightning strikes. Oil, diesel and gasoline are the substances most frequently released during lightning-triggered Natech accidents. Copyright © 2010 Elsevier B.V. All rights reserved.

  9. Climate and Lightning: An updated TRMM-LIS Analysis

    Science.gov (United States)

    Petersen, Walter A.; Buechler, D. E.

    2009-01-01

    The TRMM Lightning Imaging Sensor (LIS) has sampled global tropical and sub-tropical lightning flash densities for approximately 11 years. These data were originally processed and results presented by the authors in the 3rd AMS MALD Conference held in 2007 using both pre and post TRMM-boost lightning data. These data were normalized for the orbit boost by scaling the pre-boost data by a fixed constant based on the different swath areas for the pre and post-boost years (post-boost after 2001). Inevitably, one must question this simple approach to accounting for the orbit boost when sampling such a noisy quantity. Hence we are in the process of reprocessing the entire 11-year TRMM LIS dataset to reduce the orbit swath of the post-boost era to that of the pre-boost in order to eliminate sampling bias in the dataset. Study of the diurnal/seasonal/annual sampling suggests that those biases are already minimal and should not contribute to error in examination of annual trends. We will present new analysis of the 11-year annual trends in total lightning flash density for all latitudinal belts and select regions/regimes of the tropics as related to conventional climate signals and precipitation contents in the same period. The results should enable us to address, in some fashion, the sensitivity of the lightning flash density to subtle changes in climate.

  10. Impact Of Total Quality Management (TQM), Activity Based Costing ...

    African Journals Online (AJOL)

    Time (JIT), and Total Quality Management (TQM) as strategic initiatives lead to improved financial performance in the Turkish textile industry. Strong evidence emerged that there is a strong positive association between using ABC, JIT or TQM ...

  11. Ball lightning caused by a semi-relativistic runaway electron avalanche

    Science.gov (United States)

    Paiva, Geron S.; Taft, Carlton A.; Furtado, Nelson C. C. P.; Carvalho, Marcos C.; Hering, Eduardo N.; Vinícius, Marcus; Ronaldo, F. L.; De la Cruz, Neil M.

    2014-12-01

    Ball lightning (BL) is observed as a luminous sphere in regions of thunderstorm activity. There are many reports of BL forming in total absence of thunderclouds, associated with earthquakes and volcanoes. In this latter case, BL has been known to appear out of “nowhere”. In this work, a hypothesis on BL formation is presented involving the interaction between very low frequency (VLF) radio waves and atmospheric plasmas. High-velocity light balls are produced by ionic acoustic waves (IAWs) interacting with a stationary plasma. Several physical properties (color, velocity, and fragmentation) observed in the BL phenomenon can be explained through this model.

  12. Analysis of the electric field changes due to lightning during Catalonia thunderstorms in Summer 2003

    OpenAIRE

    Montañá Puig, Juan; Bergas Jané, Joan Gabriel; Pineda Ruegg, Nicolau; Bech, Joan; Rigo, Tomeu; Illa Arnau, Àngel; Hermoso Alameda, Blas

    2004-01-01

    Electric fields related to lightning close to storms were measured in the Catalonian region (NE of Spain) in summer 2003. The aim of this campaign was the data collection to study the total electrical charge involved in each flash.

  13. GRIP LIGHTNING INSTRUMENT PACKAGE (LIP) V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The GRIP Lightning Instrument Package (LIP) dataset was collected by the Lightning Instrument Package (LIP), which consists of 6 rotating vane type electric field...

  14. NAMMA ATD LIGHTNING DATA V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The NAMMA ATD Lightning data provided by the UK Meterological Office from multiple outstations contains lightning stroke data, latitude and longitude, accuracy and...

  15. Lightning NOx and Impacts on Air Quality

    Science.gov (United States)

    Murray, Lee T.

    2016-01-01

    Lightning generates relatively large but uncertain quantities of nitrogen oxides, critical precursors for ozone and hydroxyl radical (OH), the primary tropospheric oxidants. Lightning nitrogen oxide strongly influences background ozone and OH due to high ozone production efficiencies in the free troposphere, effecting small but non-negligible contributions to surface pollutant concentrations. Lightning globally contributes 3-4 ppbv of simulated annual-mean policy-relevant background (PRB) surface ozone, comprised of local, regional, and hemispheric components, and up to 18 ppbv during individual events. Feedbacks via methane may counter some of these effects on decadal time scales. Lightning contributes approximately 1 percent to annual-mean surface particulate matter, as a direct precursor and by promoting faster oxidation of other precursors. Lightning also ignites wildfires and contributes to nitrogen deposition. Urban pollution influences lightning itself, with implications for regional lightning-nitrogen oxide production and feedbacks on downwind surface pollution. How lightning emissions will change in a warming world remains uncertain.

  16. GAI LIGHTNING GROUND STRIKES V1

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set is restricted to EOS affiliated researchers. The U.S. National Lightning Detection Network is a commercial lightning detection network operated by...

  17. GAI LONG RANGE LIGHTNING NETWORK V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The US National Lightning Detection Network is a commercial network that records the time, polarity, signal strength, and number of cloud-to-ground lightning flashes...

  18. NAMMA LIGHTNING ZEUS DATA V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The NAMMA Lightning ZEUS data is provided by World-ZEUS Long Range Lightning Monitoring Network Data obtained from radio atmospheric signals located at thirteen...

  19. Cloud-to-ground lightning in Hurricane Andrew

    Science.gov (United States)

    Molinari, John; Moore, Paul K.; Idone, Vincent P.; Henderson, Ronald W.; Saljoughy, Arsalan B.

    1994-08-01

    The spatial and temporal distribution of cloud-to-ground lightning was examined in Hurricane Andrew of 1992. Lightning locations available from the National Lightning Detection Network were superimposed on infrared satellite images to relate lightning activity to hurricane cloud structure. A distinct radial variation occurred in time-averaged flash density, with a weak maximum in the eye wall, a region of near-zero flash density 40 to 100 km from the center, and a steady increase to a large maximum in the outer rainbands 190 km from the center. This radial distribution is consistent with the convective structure of mature hurricanes. Eye wall lightning tended to be episodic, occurring almost exclusively prior to and during periods of intensification of the storm. During these periods, negative flashes occurred several kilometers inward from the highest eye wall cloud tops, in the region of the largest radar reflectivity. Positive eye wall flashes, while small in number, tended to occur directly under the highest cloud tops. The results are suggestive of a normal dipole in sign but outwardly tilted along the sloping eye wall. In general, hurricane flash characteristics resembled those for a background data set of nonhurricane flashes from the same area. The exception occurred for negative flashes in the eye wall, which had a much smaller mean peak current than the background (25.3 kA versus 44.9 kA).

  20. Sprites, lightning, cloudtop temperatures and mesospheric electric field

    Science.gov (United States)

    São Sabbas, F.; Sentman, D.; Taylor, M.; Wescott, E.; Stenbaek-Nielsen, H.

    2003-04-01

    Sprites are one of the optical manifestations of electrical energy deposition in the mesosphere by lightning activity in the troposphere. Observations obtained from the Space Shuttle, and during ground and aircraft campaigns conducted in the U.S., Peru, Central America, Australia, Japan, Europe, Taiwan, and Brazil have confirmed the global aspect these phenomena. In order to better understand the mechanism and implications of energy deposition in the mesosphere, detailed studies of the characteristics of spatial and temporal relationship between sprites and lightning, and the characteristics of the generating meteorological system and of the surrounding atmosphere at the locations where sprites have been observed are necessary. The full problem includes consideration of both the source (lightning) characteristics, as well as the ambient medium where sprite ignition occurs. This paper summarizes results of a PhD thesis that examines (1) the observed relationships between the distribution of distance and time delays between the sprites and underlying causative lightning, (2) the correlations between sprites, lightning and cloudtop temperatures extracted from IR satellite images, and (3) the structure of electric fields in an inhomogeneous conductivity distribution at sprite initiation altitudes 75-85 km. The results suggest that conductivity inhomogeneities in the mesosphere may play an important role in determining the locations where sprite ignition occurs above a thunderstorm.

  1. Multivariate Statistical Inference of Lightning Occurrence, and Using Lightning Observations

    Science.gov (United States)

    Boccippio, Dennis

    2004-01-01

    Two classes of multivariate statistical inference using TRMM Lightning Imaging Sensor, Precipitation Radar, and Microwave Imager observation are studied, using nonlinear classification neural networks as inferential tools. The very large and globally representative data sample provided by TRMM allows both training and validation (without overfitting) of neural networks with many degrees of freedom. In the first study, the flashing / or flashing condition of storm complexes is diagnosed using radar, passive microwave and/or environmental observations as neural network inputs. The diagnostic skill of these simple lightning/no-lightning classifiers can be quite high, over land (above 80% Probability of Detection; below 20% False Alarm Rate). In the second, passive microwave and lightning observations are used to diagnose radar reflectivity vertical structure. A priori diagnosis of hydrometeor vertical structure is highly important for improved rainfall retrieval from either orbital radars (e.g., the future Global Precipitation Mission "mothership") or radiometers (e.g., operational SSM/I and future Global Precipitation Mission passive microwave constellation platforms), we explore the incremental benefit to such diagnosis provided by lightning observations.

  2. Rich extract on total polyphenols and antioxidant activity obtained by ...

    African Journals Online (AJOL)

    Conventional and non-conventional extraction methods were applied in the first time for the determination of total polyphenols from Ahmeur Bouamer, an anthoctonous variety grape seeds. Independently of the time and temperature, a positive effect of particle size parameter on maceration has been noted and relativly high ...

  3. rich extract on total polyphenols and antioxidant activity obtained by ...

    African Journals Online (AJOL)

    Z. Ghouila

    Received: 04 March 2016 / Accepted: 06 August 2016 / Published online: 01 Septembre 2016. ABSTRACT: Conventional and non-conventional extraction methods were applied in the first time for the determination of total polyphenols from Ahmeur Bouamer, an anthoctonous variety grape seeds. Independently of the time ...

  4. Antioxidant activity, total phenolic and flavonoid contents of the ...

    African Journals Online (AJOL)

    Elytraria marginata (Vahl) isused in Nigeria folk medicine as febrifuges, pulmonary problems and cancer related ailments. This study evaluated scientifically the phytochemical screening, antioxidant, total phenolic and flavonoids contents of the whole plant extract with a view to validate its folkloric usage. The phytochemical ...

  5. Antioxidant activity and total phenolic and flavonoid content of ...

    African Journals Online (AJOL)

    ajl yemi

    2011-12-19

    Dec 19, 2011 ... purposes. Medicinal values of these compounds are well ... The present report describes the total phenolics and flavonoids .... an electron donated by an antioxidant compound, the. DPPH is decolorized, which can be quantitatively mea- sured from the changes in absorbance. The IC50 value of the extract ...

  6. Antioxidant, Phytotoxic and Antiurease Activities, and Total Phenolic ...

    African Journals Online (AJOL)

    Purpose: To evaluate the antioxidant, phytotoxic and anti-urease properties of dichloromethane and methanol extracts of Conocarpus lancifolius in correlation with total phenolic and flavonoid contents. Methods: The whole plant (dried aerial parts and root) of Conocarpus lancifolius was extracted successively with ...

  7. Cholinergic and anticholinesterase activities of total protein extract ...

    African Journals Online (AJOL)

    Traditional herbal medicines such as Morinda morindoïdes are used for treatment of intestinal disorders including constipation in Ivory Coast. The aim of present study was to investigate the effect of total protein of Morinda morindoïdes extract (PT-Mm) on rabbit duodenum contractility and the involved possible ...

  8. Total phenolic, condensed tannin and antioxidant activity of four ...

    African Journals Online (AJOL)

    Different species of functional agricultural crops may vary in antioxidant capacities. In this study, the antioxidant activities of methanol extracts from four species of Carya genus were compared by various antioxidant assays, including the reducing power, 1,1-diphenyl-2-pycrylhydrazyl (DPPH) radical scavenging activity and ...

  9. Spatial and temporal analysis of a 17-year lightning climatology over Bangladesh with LIS data

    Science.gov (United States)

    Dewan, Ashraf; Ongee, Emmanuel T.; Rahman, Md. Masudur; Mahmood, Rezaul; Yamane, Yusuke

    2017-10-01

    Using NASA's TRMM Lightning Imaging Sensor (LIS) data from 1998 to 2014, this paper presents a 17-year lightning climatology of Bangladesh, at 0.5° × 0.5° spatial resolution. Diurnal, seasonal, monthly and annual variations in the occurrence of lightning flashes were explored. The diurnal regime of lightning is dominated by afternoon/evening events. Overall, peak lightning activity occurs in the early morning (0200 LST) and evening (1900 LST). The distribution of lightning flash counts by season over Bangladesh landmass is as follows: pre-monsoon (69.2%), monsoon (24.1%), post-monsoon (4.6%) and winter (2.1%). Flash rate density (FRD) hotspots were primarily located in the north and north-eastern parts of Bangladesh, with a maximum of 72 fl km-2 year-1. Spatially, the distribution of FRD increases from the Bay of Bengal in the south to relatively higher elevations (of the Himalayan foothills) in the north. A spatial shift in FRD hotspots occurs with change in season. For example, in monsoon season, hotspots of lightning activity move in a south-westerly direction from their pre-monsoon location (i.e. north-eastern Bangladesh) towards West Bengal in India. South and south-eastern parts of Bangladesh experience high lightning activity during post-monsoon season due to regional orographic lifting and low-pressure systems (i.e. cyclone) in the Bay of Bengal. To the best of our knowledge, this is the first study focused on LIS-based lightning climatology over Bangladesh. This baseline study, therefore, is an essential first step towards effective management of lightning-related hazards in Bangladesh.

  10. Insight into the Physical and Dynamical Processes that Control Rapid Increases in Total Flash Rate

    Science.gov (United States)

    Schultz, Christopher J.; Carey, Lawrence D.; Schultz, Elise V.; Blakeslee, Richard J.; Goodman, Steven J.

    2015-01-01

    Rapid increases in total lightning (also termed "lightning jumps") have been observed for many decades. Lightning jumps have been well correlated to severe and hazardous weather occurrence. The main focus of lightning jump work has been on the development of lightning algorithms to be used in real-time assessment of storm intensity. However, in these studies it is typically assumed that the updraft "increases" without direct measurements of the vertical motion, or specification of which updraft characteristic actually increases (e.g., average speed, maximum speed, or convective updraft volume). Therefore, an end-to-end physical and dynamical basis for coupling rapid increases in total flash rate to increases in updraft speed and volume must be understood in order to ultimately relate lightning occurrence to severe storm metrics. Herein, we use polarimetric, multi-Doppler, and lightning mapping array measurements to provide physical context as to why rapid increases in total lightning are closely tied to severe and hazardous weather.

  11. Volcanic lightning and plume behavior reveal evolving hazards during the April 2015 eruption of Calbuco volcano, Chile

    Science.gov (United States)

    Van Eaton, Alexa; Amigo, Álvaro; Bertin, Daniel; Mastin, Larry G.; Giacosa, Raúl E; González, Jerónimo; Valderrama, Oscar; Fontijn, Karen; Behnke, Sonja A

    2016-01-01

    Soon after the onset of an eruption, model forecasts of ash dispersal are used to mitigate the hazards to aircraft, infrastructure and communities downwind. However, it is a significant challenge to constrain the model inputs during an evolving eruption. Here we demonstrate that volcanic lightning may be used in tandem with satellite detection to recognize and quantify changes in eruption style and intensity. Using the eruption of Calbuco volcano in southern Chile on 22-23 April 2015, we investigate rates of umbrella cloud expansion from satellite observations, occurrence of lightning, and mapped characteristics of the fall deposits. Our remote-sensing analysis gives a total erupted volume that is within uncertainty of the mapped volume (0.56 ±0.28 km3 bulk). Observations and volcanic plume modeling further suggest that electrical activity was enhanced both by ice formation in the ash clouds >10 km asl and development of a low-level charge layer from ground-hugging currents.

  12. Chemical Composition of the Essential Oil, Total Phenolics, Total Flavonoids and Antioxidant Activity of Methanolic Extracts of Satureja montana L.

    Directory of Open Access Journals (Sweden)

    Avni Hajdari

    2016-05-01

    Full Text Available Aerial parts of Satureja montana L. (Lamiaceae were collected from seven growing wild populations (four populations in Kosovo, two in Albania and one in Montenegro in 2013 with the aim of assessing the natural variation in the chemical composition of the essential oils, total flavonoids, total phenolics and the antioxidant activity of their methanolic extracts. Essential oils were obtained by steam distillation and analysed using GC-FID and GC-MS, whereas total flavonoids, total phenolics and antioxidant activities were determined using spectrophotometric methods. Sixty-one volatile constituents were identified. The main constituents were myrcene, p-cymene, γ-terpinene, linalool, thymol, carvacrol and viridiflorol. Total phenolics ranged from 68.1 to 102.6 mg/g dry mass, the total flavonoid content ranged from 38.3 to 67.0 mg/g dm, and the antioxidant activity according to the DPPH assay ranged from 253.3 to 342.9 mg TE/g dm and according to the FRAP assay ranged from 8.9 to 11.4 mg TE/g dm. Hierarchical cluster analysis and principal component analyses were used to assess the geographical variations in the essential oil composition. Statistical analysis revealed that the analysed populations are grouped into four main clusters that appear to reflect the environmental impact on the chemical composition, which is influenced by differences in habitat composition, altitude and microclimatic conditions.

  13. Z-M in lightning forecasting

    OpenAIRE

    Machina, Alexia J.

    2009-01-01

    Approved for public release, distribution unlimited Frozen hydrometeors are required for a storm to produce lightning. Previous research has made strong correlations between ice mass and lightning flash rate and lightning flash density. This study attempted to correlate ice mass to lightning potential Operational interest is centered at Cape Canaveral Air Force Station/Kennedy Space Center where accurate weather forecasting is vital to mission requirements, resource protection, and pe...

  14. Physical and Dynamical Linkages Between Lightning Jumps and Storm Conceptual Models

    Science.gov (United States)

    Schultz, Christopher J.; Carey, Lawrence D.; Schultz, Elise V.; Blakeslee, Richard J.; Goodman, Steven J.

    2014-01-01

    The presence and rates of total lightning are both correlated to and physically dependent upon storm updraft strength, mixed phase precipitation volume and the size of the charging zone. The updraft modulates the ingredients necessary for electrification within a thunderstorm, while the updraft also plays a critical role in the development of severe and hazardous weather. Therefore utilizing this relationship, the monitoring of lightning rates and jumps provides an additional piece of information on the evolution of a thunderstorm, more often than not, at higher temporal resolution than current operational radar systems. This correlation is the basis for the total lightning jump algorithm that has been developed in recent years. Currently, the lightning jump algorithm is being tested in two separate but important efforts. Schultz et al. (2014; this conference) is exploring the transition of the algorithm from its research based formulation to a fully objective algorithm that includes storm tracking, Geostationary Lightning Mapper (GLM) Proxy data and the lightning jump algorithm. Chronis et al. (2014) provides context for the transition to current operational forecasting using lightning mapping array based products. However, what remains is an end-to-end physical and dynamical basis for coupling total lightning flash rates to severe storm manifestation, so the forecaster has a reason beyond simple correlation to utilize the lightning jump algorithm within their severe storm conceptual models. Therefore, the physical basis for the lightning jump algorithm in relation to severe storm dynamics and microphysics is a key component that must be further explored. Many radar studies have examined flash rates and their relationship to updraft strength, updraft volume, precipitation-sized ice mass, etc.; however, their relationship specifically to lightning jumps is fragmented within the literature. Thus the goal of this study is to use multiple Doppler and polarimetric

  15. Plant cytoplasm preserved by lightning.

    Science.gov (United States)

    Wang, X

    2004-10-01

    Usually only an organism with hard parts may be preserved in the fossil record. Cytoplasm, which is a physiologically active part of a plant, is rarely seen in the fossil record. Two Cretaceous plant fossils older than 100 million years with exceptional preservation of cytoplasm are reported here. Some cytoplasm is well preserved with subcellular details while other cytoplasm is highly hydrolyzed in the cortex of the same fossil even though both of preservations may be less than 2 microm away. The unique preservation pattern, sharp contrast of preservation in adjacent cells and the exceptional preservation of cytoplasm in the cortex suggest that lightning should play an important role in the preservation of cytoplasm and that cytoplasmic membranes may be more stable than the cell contents. Interpreting the preservation needs knowledge scattering in several formerly unrelated fields of science, including geophysics, botany, biophysics, cytology and microwave fixation technology. This new interpretation of fossilization will shed new light on preservation of cytoplasm and promote cytoplasm fossils from a position of rarity to a position of common research objects available for biological research. The importance of the identification of cytoplasm in fossil lies not in itself but in how much it influences the future research in paleobotany.

  16. Statistical analysis of storm electrical discharges reconstituted from a lightning mapping system, a lightning location system, and an acoustic array

    Science.gov (United States)

    Gallin, Louis-Jonardan; Farges, Thomas; Marchiano, Régis; Coulouvrat, François; Defer, Eric; Rison, William; Schulz, Wolfgang; Nuret, Mathieu

    2016-04-01

    In the framework of the European Hydrological Cycle in the Mediterranean Experiment project, a field campaign devoted to the study of electrical activity during storms took place in the south of France in 2012. An acoustic station composed of four microphones and four microbarometers was deployed within the coverage of a Lightning Mapping Array network. On the 26 October 2012, a thunderstorm passed just over the acoustic station. Fifty-six natural thunder events, due to cloud-to-ground and intracloud flashes, were recorded. This paper studies the acoustic reconstruction, in the low frequency range from 1 to 40 Hz, of the recorded flashes and their comparison with detections from electromagnetic networks. Concurrent detections from the European Cooperation for Lightning Detection lightning location system were also used. Some case studies show clearly that acoustic signal from thunder comes from the return stroke but also from the horizontal discharges which occur inside the clouds. The huge amount of observation data leads to a statistical analysis of lightning discharges acoustically recorded. Especially, the distributions of altitudes of reconstructed acoustic detections are explored in detail. The impact of the distance to the source on these distributions is established. The capacity of the acoustic method to describe precisely the lower part of nearby cloud-to-ground discharges, where the Lightning Mapping Array network is not effective, is also highlighted.

  17. 14 CFR 35.38 - Lightning strike.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Lightning strike. 35.38 Section 35.38... STANDARDS: PROPELLERS Tests and Inspections § 35.38 Lightning strike. The applicant must demonstrate, by... lightning strike without causing a major or hazardous propeller effect. The limit to which the propeller has...

  18. 14 CFR 420.71 - Lightning protection.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Lightning protection. 420.71 Section 420.71... TRANSPORTATION LICENSING LICENSE TO OPERATE A LAUNCH SITE Responsibilities of a Licensee § 420.71 Lightning protection. (a) Lightning protection. A licensee shall ensure that the public is not exposed to hazards due...

  19. Relating lightning data to fire occurrence data

    Science.gov (United States)

    F.H. Koch

    2009-01-01

    Lightning disturbance can affect forest health at various scales. Lightning strikes may kill or weaken individual trees. Lightning-damaged trees may in turn function as epicenters of pest outbreaks in forest stands, as is the case with the southern pine beetle and other bark beetles (Rykiel and others 1988).

  20. 49 CFR 176.120 - Lightning protection.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Lightning protection. 176.120 Section 176.120 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS MATERIALS SAFETY... Requirements for Class 1 (Explosive) Materials Stowage § 176.120 Lightning protection. A lightning conductor...

  1. Wind turbine with lightning protection system

    DEFF Research Database (Denmark)

    2016-01-01

    The present invention relates to a wind turbine comprising a lightning protection system comprising a waveguide interconnecting a communication device and a signal-carrying structure. In other aspects, the present invention relates to the use of a waveguide in a lightning protection system...... of a wind turbine, a power splitter and its use in a lightning protection system of a wind turbine....

  2. Lightning Protection for Composite Aircraft Structures

    Science.gov (United States)

    Olson, G. O.

    1985-01-01

    Lightning protection system consisting of two layers of aluminum foil separated by layer of dielectric material protects graphite/epoxy composite structures on aircraft. Protective layer is secondarily applied lightning protection system, prime advantage of which is nullification of thermal and right angle effect of lightning arc attachment to graphite/epoxy laminate.

  3. Attempts to create ball lightning with triggered lightning

    Science.gov (United States)

    Hill, Jonathan D.; Uman, Martin A.; Stapleton, Michael; Jordan, Douglas M.; Chebaro, Alexander M.; Biagi, Christopher J.

    2010-08-01

    We describe attempts to create ball lightning by directing lightning, triggered from natural thunderclouds using the rocket-and-wire technique, through a variety of materials. Some of the observed phenomena have features in common with natural ball lightning or with laboratory attempts to create it: flame-like luminosity for up to 0.5 s above salt water; constant-luminosity silicon fragments falling for about 1 s under the influence of gravity; a 0.7 m region of stationary luminosity whose bottom was 0.3 m above a stainless steel surface to which arcing had occurred; and a glow for about 0.5 s above pine tree sections.

  4. ELF Electromagnetic Waves from Lightning: The Schumann Resonances

    Directory of Open Access Journals (Sweden)

    Colin Price

    2016-09-01

    Full Text Available Lightning produces electromagnetic fields and waves in all frequency ranges. In the extremely low frequency (ELF range below 100 Hz, the global Schumann Resonances (SR are excited at frequencies of 8 Hz, 14 Hz, 20 Hz, etc. This review is aimed at the reader generally unfamiliar with the Schumann Resonances. First some historical context to SR research is given, followed by some theoretical background and examples of the extensive use of Schumann resonances in a variety of lightning-related studies in recent years, ranging from estimates of the spatial and temporal variations in global lighting activity, connections to global climate change, transient luminous events and extraterrestrial lightning. Both theoretical and experimental results of the global resonance phenomenon are presented. It is our hope that this review will increase the interest in SR among researchers previously unfamiliar with this phenomenon.

  5. Positive lightning and severe weather

    Science.gov (United States)

    Price, C.; Murphy, B.

    2003-04-01

    In recent years researchers have noticed that severe weather (tornados, hail and damaging winds) are closely related to the amount of positive lightning occurring in thunderstorms. On 4 July 1999, a severe derecho (wind storm) caused extensive damage to forested regions along the United States/Canada border, west of Lake Superior. There were 665,000 acres of forest destroyed in the Boundary Waters Canoe Area Wilderness (BWCAW) in Minnesota and Quetico Provincial Park in Canada, with approximately 12.5 million trees blown down. This storm resulted in additional severe weather before and after the occurrence of the derecho, with continuous cloud-to-ground (CG) lightning occurring for more than 34 hours during its path across North America. At the time of the derecho the percentage of positive cloud-to-ground (+CG) lightning measured by the Canadian Lightning Detection Network (CLDN) was greater than 70% for more than three hours, with peak values reaching 97% positive CG lightning. Such high ratios of +CG are rare, and may be useful indicators for short-term forecasts of severe weather.

  6. Two upward lightning at the Eagle Nest tower

    OpenAIRE

    Montañá Puig, Juan; Van der Velde, Oscar Arnoud; Romero Durán, David; March Nomen, Víctor; Solà de Las Fuentes, Gloria; Pineda Ruegg, Nicolau; Soula, Serge; Hermoso Alameda, Blas

    2012-01-01

    A new instrument composed by a high speed camera, two high energy detectors, a E-field antenna and a VHF antenna were installed at the Eagle Nest tower (northeast of Spain) during summer 2011. With this equipment several lightning flashes to the tower and its vicinity have been observed. This paper presents two examples: the first was an upward negative leader triggered by a close c1oud-to-ground flash and the second was an upward negative flash not associated with previous lightning activity...

  7. Total synthesis and allelopathic activity of cytosporones A-C

    Energy Technology Data Exchange (ETDEWEB)

    Zamberlam, Charles E.M.; Meza, Alisson; Lima, Denis P. de; Beatriz, Adilson [Centro de Ciencias Exatas e Tecnologia, Universidade Federal de Mato Grosso do Sul, Campo Grande, MS (Brazil); Leite, Carla Braga; Marques, Maria Rita [Centro de Ciencias Biologicas e da Saude, Universidade Federal de Mato Grosso do Sul, Campo Grande, MS (Brazil)

    2012-07-01

    The search for efficient, environmentally friendly herbicides has been the focus of numerous studies on the organic synthesis of compounds isolated from natural sources. Cytosporones, which are phenolic lipids isolated from fungi, exhibit noteworthy biological properties. This paper reports the preparation of cytosporones A-C from the same starting material through a short synthetic route, with good yields. All compounds were tested for allelopathic activity on lettuce (Lactuca sativa L) seeds. Cytosporone A and its methylated precursor showed remarkable allelopathic activity, inhibiting seed germination and plantule growth. (author)

  8. Haemoglobin and Lung Total and Lysosomal Phosphatase Activity ...

    African Journals Online (AJOL)

    Smoking of ordinary cigarette exposes its active smokers to health hazards and the filter-tipped cigarette, is said to reduce the hazards. However, it is not certain if the filter-tipped cigarette reduces the hazards in passive smokers since they inhail the cigarette smoke through their nostrils regardless of whether the cigarette is ...

  9. total phenols and antioxidant activities of natural honeys

    African Journals Online (AJOL)

    B. S. Chandravanshi

    substance produced by honeybees (Apis mellifera) from the nectar of blossoms and secretions of plants. It is known to have both enzymatic and non-enzymatic antioxidant activities [2, 3]. Though, honey is a highly supersaturated solution of a complex mixture of sugars, it also contains small amount of other constituents ...

  10. Antioxidant activity and total phenolic and flavonoid content of ...

    African Journals Online (AJOL)

    The antioxidant capacity of the flowering aerial parts of Astragalus squarrosus was determined by 1,1- diphenyl-2-picrylhydrazyl (DPPH) radical scavenging and ferric thiocyanate methods. The phenolic and flavonoid content was also measured. A. squarrosus showed weak free radical scavenging activity with the DPPH ...

  11. Response of total phenolic content and antioxidant activities of bush

    African Journals Online (AJOL)

    user

    the shade at ambient temperature (Mudau and. Ngezimana, 2014) before being ground with a commercial .... Saturated solution of sodium bicarbonate (20% Na2CO3,. 7.5 ml) was added to the reaction before it was ..... Effects of solvent extraction on phenolic content and antioxidant activity of the by-product of eggplant ...

  12. Recent Lightning Experiments at the International Center for Lightning Research and Testing: From Ball Lightning to Gamma Rays

    Science.gov (United States)

    Uman, M. A.

    2008-12-01

    Recent lightning data and the instrumentation used to acquire it at the UF-FIT International Center for Lightning Research and Testing, located on about 1 square kilometer of flat ground at the Camp Blanding Army National Guard Base in north-central Florida, are discussed. The progress of several on-going studies is reviewed: (1) understanding the physics of the "classical" rocket-and-wire triggering of lightning from natural overhead thunderclouds, (2) attempting to generate ball lightning by allowing triggered-lightning to strike various materials and objects (e.g., tree-trunk sections, pools of salt water, silicon powder), (3) measuring the very close (100 m to 1 km) electric and magnetic fields of natural cloud-to-ground lightning, and (4) probing the relationship between lightning processes and the x-rays and gamma-rays associated with them.

  13. Whole-body dose meters. Measurements of total activity

    International Nuclear Information System (INIS)

    Koeppe, P.; Klinikum Steglitz, Berlin

    1990-01-01

    By means of measurements using a whole-body dose meter, the course of the incorporation of radionuclides was established between April 1986 and May 1989 for unchanged conditions of alimentation, activity-conscious alimentation, and uniquely increased incorporation. Monitoring covered persons from the most different spheres of life. The incorporation is compared with the one resulting from nuclear weapons explosions in the atmosphere. (DG) [de

  14. Structure of laboratory ball lightning

    Science.gov (United States)

    Ito, Tsuyohito; Tamura, Tomoya; Cappelli, Mark A.; Hamaguchi, Satoshi

    2009-12-01

    Trajectories of self-sustained laboratory ball lightning, generated by arc discharges with silicon, are investigated for understanding the possibility of buoyant flight. Extremely low apparent densities are found, nearly approaching that of standard air. The freely buoyant balls are observed to survive for about 0.1 s, with significantly buoyant balls surviving for several seconds. These ball lightning objects are found to have a density and size that can easily allow them to be carried by a gentle breeze of a few meters per second. The results are interpreted by a model that is an extension of that first proposed by Abrahamson and Dinniss [J. Abrahamson and J. Dinniss, Nature (London) 403, 519 (2000)]. The buoyant behavior of ball lightning seen in our experiments is believed to arise as a result of the formation of a nanoparticle oxide network growing from a molten silicon core.

  15. Lightning Imaging Sensor (LIS) for the International Space Station (ISS): Mission Description and Science Goals

    Science.gov (United States)

    Blakeslee, R. J.; Christian, H. J.; Mach, D. M.; Buechler, D. E.; Koshak, W. J.; Walker, T. D.; Bateman, M.; Stewart, M. F.; O'Brien, S.; Wilson, T.; hide

    2015-01-01

    In recent years, the NASA Marshall Space Flight Center, the University of Alabama in Huntsville, and their partners have developed and demonstrated space-based lightning observations as an effective remote sensing tool for Earth science research and applications. The Lightning Imaging Sensor (LIS) on the Tropical Rainfall Measuring Mission (TRMM) continues to acquire global observations of total (i.e., intracloud and cloud-to-ground) lightning after 17 years on-orbit. However, TRMM is now low on fuel, so this mission will soon be completed. As a follow on to this mission, a space-qualified LIS built as the flight spare for TRMM has been selected for flight as a science mission on the International Space Station (ISS). The ISS LIS will be flown as a hosted payload on the Department of Defense Space Test Program (STP) H5 mission, which has a January 2016 baseline launch date aboard a SpaceX launch vehicle for a 2-4 year or longer mission. The LIS measures the amount, rate, and radiant energy of total lightning over the Earth. More specifically, it measures lightning during both day and night, with storm scale resolution (approx. 4 km), millisecond timing, and high, uniform detection efficiency, without any land-ocean bias. Lightning is a direct and most impressive response to intense atmospheric convection. It has been found that lightning measured by LIS can be quantitatively related to thunderstorm and other geophysical processes. Therefore, the ISS LIS lightning observations will continue to provide important gap-filling inputs to pressing Earth system science issues across a broad range of disciplines, including weather, climate, atmospheric chemistry, and lightning physics. A unique contribution from the ISS platform will be the availability of real-time lightning data, especially valuable for operational applications over data sparse regions such as the oceans. The ISS platform will also uniquely enable LIS to provide simultaneous and complementary observations

  16. The Sao Paulo Lightning Mapping Array (SPLMA): Prospects to GOES-R GLM and CHUVA

    Science.gov (United States)

    Albrecht, Rachel I.; Carrey, Larry; Blakeslee, Richard J.; Bailey, Jeffrey C.; Goodman, Steven J.; Bruning, Eric C.; Koshak, William; Morales, Carlos A.; Machado, Luiz A. T.; Angelis, Carlos F.; hide

    2010-01-01

    This paper presents the characteristics and prospects of a Lightning Mapping Array to be deployed at the city of S o Paulo (SPLMA). This LMA network will provide CHUVA campaign with total lightning, lightning channel mapping and detailed information on the locations of cloud charge regions for the thunderstorms investigated during one of its IOP. The real-time availability of LMA observations will also contribute to and support improved weather situational awareness and mission execution. For GOES-R program it will form the basis of generating unique and valuable proxy data sets for both GLM and ABI sensors in support of several on-going research investigations

  17. Fluorescence caused by ionizing radiation from ball lightning: Observation and quantitative analysis

    Science.gov (United States)

    Stephan, Karl D.; Krajcik, Rozlyn; Martin, Rolf J.

    2016-10-01

    Ball lightning is a rare phenomenon, typically appearing as a glowing sphere associated with thunderstorms. In 2008 one of the authors witnessed a blue ball-lightning object hover in front of a glass window that appeared to glow yellow. Calibrated quantitative fluorometry measurements of the window show that the glow was probably due to fluorescence caused by ionizing radiation (UV or possibly X rays). Based on the measurements performed, estimates of the total ionizing-radiation power emitted by the object range upward from about 10 W. These are among the most reliable semi-quantitative measurements so far of ionizing-radiation output from a ball-lightning object.

  18. Understanding Changes in Modeled Land Surface Characteristics Prior to Lightning-Initiated Holdover Fire Breakout

    Science.gov (United States)

    Schultz, Christopher J.; Case, Jonathan L.; Hain, Christopher R.; White, Kristopher; Wachter, J. Brent; Nauslar, Nicholas; MacNamara, Brittany

    2018-01-01

    Lightning initiated wildfires are only 16% of the total number of wildfires within the United States, but account for 56% of the acreage burned. One of the challenges with lightning-initiated wildfires is their ability to "holdover" which means smolder for up to 2+ weeks before breaking out into a full fledged fire. This work helps characterize the percentage of holdover events due to lightning, and helps quantify changes in the land surface characteristics to help understand trends in soil moisture and vegetation stress that potentially contribute to the fire breaking out into a full wildfire.

  19. Lightning mapper development: Status and requirements

    Science.gov (United States)

    Christian, H. J.

    1984-01-01

    The feasibility for the detection and location of lightning on a continuous basis using a sensor in geostationary orbit was established. Measurements of the optical characteristics of lightning and the capabilities of solid state mosaic focal plane arrays, indicate that the question is how high a detection efficiency can be achieved. The lightning mapper development to strengthen the scientific justification for placing a lightning sensor in geostationary orbit is discussed. The U-2 and ground based lightning research, modeling, and theoretical studies are reported.

  20. Lightning and its association with the frequency of headache in migraineurs: an observational cohort study.

    Science.gov (United States)

    Martin, Geoffrey V; Houle, Timothy; Nicholson, Robert; Peterlin, Albert; Martin, Vincent T

    2013-04-01

    The aim of this article is to determine if lightning is associated with the frequency of headache in migraineurs. Participants fulfilling diagnostic criteria for International Headache Society-defined migraine were recruited from sites located in Ohio ( N  = 23) and Missouri ( N  = 67). They recorded headache activity in a daily diary for three to six months. A generalized estimating equations (GEE) logistic regression determined the odds ratio (OR) of headache on lightning days compared to non-lightning days. Other weather factors associated with thunderstorms were also added as covariates to the GEE model to see how they would attenuate the effect of lightning on headache. The mean age of the study population was 44 and 91% were female. The OR for headache was 1.31 (95% confidence limits (CL); 1.07, 1.66) during lighting days as compared to non-lightning days. The addition of thunderstorm-associated weather variables as covariates were only able to reduce the OR for headache on lightning days to 1.18 (95% CL; 1.02, 1.37). The probability of having a headache on lightning days was also further increased when the average current of lightning strikes for the day was more negative. This study suggests that lightning represents a trigger for headache in migraineurs that cannot be completely explained by other meteorological factors. It is unknown if lightning directly triggers headaches through electromagnetic waves or indirectly through production of bioaerosols (e.g. ozone), induction of fungal spores or other mechanisms. These results should be interpreted cautiously until replicated in a second dataset.

  1. Rhodium in car exhaust tips by total automatic activation analysis

    International Nuclear Information System (INIS)

    Grass, F.; Westphal, G.P.; Lemmel, H.; Sterba, J.

    2007-01-01

    Exhaust systems of modern cars contain catalysts for the reduction of CO, NO x and hydrocarbons. These catalysts are made of ceramic materials with a large surface on which platinum metals catalyse the oxidation. The catalysts contain approximately 2 g of platinum and 0.4 g of rhodium. Recently platinum is being replaced by palladium. During driving the platinum-group elements (PGEs) are expelled from the tip in fine particles and are deposited in the environment. For a projected study of emissions from cars driven on streets and highways it is important to know which elements can be measured by short time activation analysis without any chemical procedure. (author)

  2. Fiber-Optic Sensor for Aircraft Lightning Current Measurement

    Science.gov (United States)

    Nguyen, Truong X.; Ely, Jay J.; Szatkowski, George G.; Mata, Carlos T.; Mata, Angel G.; Snyder, Gary P.

    2012-01-01

    An electric current sensor based on Faraday rotation effect in optical fiber was developed for measuring aircraft lightning current. Compared to traditional sensors, the design has many advantages including the ability to measure total current and to conform to structure geometries. The sensor is also small, light weight, non-conducting, safe from interference, and free of hysteresis and saturation. Potential applications include characterization of lightning current waveforms, parameters and paths, and providing environmental data for aircraft certifications. In an optical fiber as the sensing medium, light polarization rotates when exposed to a magnetic field in the direction of light propagation. By forming closed fiber loops around a conductor and applying Ampere s law, measuring the total light rotation yields the enclosed current. A reflective polarimetric scheme is used, where polarization change is measured after the polarized light travels round-trip through the sensing fiber. The sensor system was evaluated measuring rocket-triggered lightning over the 2011 summer. Early results compared very well against a reference current shunt resistor, demonstrating the sensor s accuracy and feasibility in a lightning environment. While later comparisons show gradually increasing amplitude deviations for an undetermined cause, the overall waveforms still compared very well.

  3. Protecting Electronic Equipment in Composite Structures against Lightning

    NARCIS (Netherlands)

    Blaj, M.A.

    2015-01-01

    Damage resulting from an interaction with lightning current in a military naval vessel, especially in a conflict zone and at the time of a conflict, which leads to the incapacitation of vital activities on the ship, is unacceptable. Because many potential conflict zones are in littoral areas, and

  4. Physical nature of ball lightning

    Energy Technology Data Exchange (ETDEWEB)

    Stakhanov, I.P.

    1979-01-01

    An analysis is made of results obtained from the observations of ball lightning. Principal attention is given to data obtained during the last two decades. A brief critique is also offered on hypotheses about its origin. A more detailed presentation is made of the cluster hypothesis according to which ball lightning consists of complex compounds of ions and neutral molecules. The book is intended for a broad spectrum of readers, but is particularly directed toward those with a knowledge of physics and chemistry. 70 references, 24 figures, 17 tables.

  5. Lightning and Life on Exoplanets

    Science.gov (United States)

    Rimmer, Paul; Ardaseva, Aleksandra; Hodosan, Gabriella; Helling, Christiane

    2016-07-01

    Miller and Urey performed a ground-breaking experiment, in which they discovered that electric discharges through a low redox ratio gas of methane, ammonia, water vapor and hydrogen produced a variety of amino acids, the building blocks of proteins. Since this experiment, there has been significant interest on the connection between lightning chemistry and the origin of life. Investigation into the atmosphere of the Early Earth has generated a serious challenge for this project, as it has been determined both that Earth's early atmosphere was likely dominated by carbon dioxide and molecular nitrogen with only small amounts of hydrogen, having a very high redox ratio, and that discharges in gases with high redox ratios fail to yield more than trace amounts of biologically relevant products. This challenge has motivated several origin of life researchers to abandon lightning chemistry, and to concentrate on other pathways for prebiotic synthesis. The discovery of over 2000 exoplanets includes a handful of rocky planets within the habitable zones around their host stars. These planets can be viewed as remote laboratories in which efficient lightning driven prebiotic synthesis may take place. This is because many of these rocky exoplanets, called super-Earths, have masses significantly greater than that of Earth. This higher mass would allow them to more retain greater amounts hydrogen within their atmosphere, reducing the redox ratio. Discharges in super-Earth atmospheres can therefore result in a significant yield of amino acids. In this talk, I will discuss new work on what lightning might look like on exoplanets, and on lightning driven chemistry on super-Earths. Using a chemical kinetics model for a super-Earth atmosphere with smaller redox ratios, I will show that in the presence of lightning, the production of the amino acid glycine is enhanced up to a certain point, but with very low redox ratios, the production of glycine is again inhibited. I will conclude

  6. Spatio-temporal variability of lightning and convective activity over South/South-East Asia with an emphasis during El Niño and La Niña

    Science.gov (United States)

    Saha, Upal; Siingh, Devendraa; Midya, S. K.; Singh, R. P.; Singh, A. K.; Kumar, S.

    2017-11-01

    The present analysis investigates the spatio-temporal variability of the convective parameters and associated lightning flash rates during the period 1997-2013 including the El Niño and La Niña episode. It reveals that north-western and north-eastern part along the foothills of Himalayas as well as Indo-China peninsular region and South China Sea are much convective prone zones over the South/South-East Asia. The terrain/orography of the Himalayan range, the influence of cross-equatorial low-level jet and large-scale circulation during pre-monsoon and active phase of monsoon, the western Pacific Warm Pool with increased sea surface temperature as well as the solar-heating-originated local instability instigate the convective anomaly to propagate over the north-western and north eastern Indian sub-continent along with the Indo-China peninsula and South China Sea respectively. The land surfaces of the Indian sub-continent and the sea surface of South China Sea possesses significant correlation with lightning flash rates and convective parameters whereas the sea surface surrounding Indian sub-continent do not show such good correlations among them. Although, the occurrence of convective activities during the El Niño (La Niña) gets reduced (increased), the occurrence of lightning flashes gets enhanced (diminished) during this period which may be the direct consequence of warming atmosphere in relation to changing patterns of regional climate. Fig. S2 Spatial trend distribution per year of (a) LFR, (b) CAPE, (c) SCP, (d) LI, (e) CINE and (f) AT anomaly over South/South-East Asia during January-December for the years 1997-2013 (Trend is significant at 95% confidence level). Fig. S3 Correlation maps of LFR with (a) CAPE, (b) SCP, (c) CINE and (d) LI over South/South-East Asia during January-December for the years 1997-2013. Fig. S4 Synoptic wind direction patterns during (a)-(b) El Niño (May 2002 - February 2003) conditions and (c)-(d) La Niña (July 1998 - March

  7. LRAT: Lightning Radiative Transfer

    Science.gov (United States)

    Phanord, Dieudonne D.

    1993-01-01

    In this report, we extend to cloud physics the work done for single and multiple scattering of electromagnetic waves. We consider the scattering of light, visible or infrared, by a spherical cloud represented by a statistically homogeneous ensemble of configurations of N identical spherical water droplets whose centers are uniformly distributed in its volume V. The ensemble is specified by the average number rho of scatterers in unit volume and by rho f(R) with f(R) as the distribution function for separations R of pairs. The incident light, vector-phi(sub 0) a plane electromagnetic wave with harmonic time dependence, is from outside the cloud. The propagation parameter kappa(sub 0) and the index of refraction eta(sub 0) determine physically the medium outside the distribution of scatterers. We solve the interior problem separately to obtain the bulk parameters for the scatterer equivalent to the ensemble of spherical droplets. With the interior solution or the equivalent medium approach, the multiple scattering problem is reduced to that of an equivalent single scatterer excited from outside illumination. A dispersion relation which determines the bulk propagation parameter K and the bulk index of refraction eta of the cloud is given in terms of the vector equivalent scattering amplitude vector-G and the dyadic scattering amplitude tilde-g of the single object in isolation. Based on this transfer model we will have the ability to consider clouds composed of inhomogeneous distribution of water and/or ice particles and we will be able to take into account particle size distributions within the cloud. We will also be able to study the effects of cloud composition (i.e., particle shape, size, composition, orientation, location) on the polarization of the single or the multiple scattered waves. Finally, this study will provide a new starting point for studying the problem of lightning radiative transfer.

  8. Physical education in schools, sport activity and total physical activity in adolescents

    Directory of Open Access Journals (Sweden)

    Priscila Missaki Nakamura

    2013-07-01

    Full Text Available Less than half of adolescents reach the recommended300 minutes per week of physical activity (PA. Physical educationclasses and sports participation provideopportunities for adolescents to accumulate moretime for PA practice; however, littleis known about the influence of these variables onthe level of total physical activity ofadolescents. The aim of this study was toinvestigate the association between the practiceof physical education (PE in schools and sportsactivities (SA with the practice oftotal PA of adolescents. The study wascross-sectional and involved 467 adolescents ofhigh school (15.8 ± 0.9 years-old from the city ofRio Claro, in the State of São Paulo. Participants completed the Physical ActivityQuestionnaire to Older Children (PAQ-Cand questions related to the practice of PE and SAin schools. We performed a logisticregression with p<0.05 using SPSS. Girls hadlower prevalence of PA than boys, 9.4% and26.8%, respectively. Boys who did not participateof PE classes (OR=0.25, CI95%=0.09-0.66 and SA in schools (OR=0.34, CI95%=0.12-0.95were less likely to be active in PAthan boys who practiced these activities. Theparticipation in PE classes or engagementin some SA were positively associated with thepractice of total PA in boys.

  9. Physical education in schools, sport activity and total physical activity in adolescents

    Directory of Open Access Journals (Sweden)

    Priscila Missaki Nakamura

    2013-06-01

    Full Text Available DOI: http://dx.doi.org/10.5007/1980-0037.2013v15n5p517 Less than half of adolescents reach the recommended300 minutes per week of physical activity (PA. Physical educationclasses and sports participation provideopportunities for adolescents to accumulate moretime for PA practice; however, littleis known about the influence of these variables onthe level of total physical activity ofadolescents. The aim of this study was toinvestigate the association between the practiceof physical education (PE in schools and sportsactivities (SA with the practice oftotal PA of adolescents. The study wascross-sectional and involved 467 adolescents ofhigh school (15.8 ± 0.9 years-old from the city ofRio Claro, in the State of São Paulo. Participants completed the Physical ActivityQuestionnaire to Older Children (PAQ-Cand questions related to the practice of PE and SAin schools. We performed a logisticregression with p<0.05 using SPSS. Girls hadlower prevalence of PA than boys, 9.4% and26.8%, respectively. Boys who did not participateof PE classes (OR=0.25, CI95%=0.09-0.66 and SA in schools (OR=0.34, CI95%=0.12-0.95were less likely to be active in PAthan boys who practiced these activities. Theparticipation in PE classes or engagementin some SA were positively associated with thepractice of total PA in boys.

  10. A Fiber-Optic Current Sensor for Lightning Measurement Applications

    Science.gov (United States)

    Nguyen, Truong X.; Ely, Jay J.; Szatkowski, George N.

    2015-01-01

    An optical-fiber sensor based on Faraday Effect is developed for measuring total lightning electric current. It has many unique capabilities not possible with traditional current sensors. Designed for aircraft installation, the sensor is lightweight, non-conducting, structure-conforming, and is immune to electromagnetic interference, hysteresis and saturation. It can also be used on windmills, lightning towers, and can help validate lightning detection network measurements. Faraday Effect causes light polarization to rotate when the fiber is exposed to a magnetic field in the direction of light propagation. Thus, the magnetic field strength can be determined from the light polarization change. By forming closed fiber loops and applying Ampere's law, measuring the total light rotation yields the total current enclosed. The broadband, dual-detector, reflective polarimetric scheme allows measurement of both DC component and AC waveforms with about 60 dB dynamic range. Three sensor systems were built with different sensitivities from different laser wavelengths. Operating at 850nm, the first system uses twisted single-mode fiber and has a 150 A - 150 KA range. The second system operates at 1550nm, uses spun polarization maintaining fiber, and can measure 400 A - 400 KA. Both systems were validated with rocket-triggered lightning measurements and achieved excellent results when compared to a resistive shunt. The third system operates at 1310nm, uses spun polarization maintaining fiber, and can measure approximately 300 A - 300 KA. High current measurements up to 200 KA were demonstrated at a commercial lightning test facility. The system was recently installed on an aircraft and flown near icing weather conditions.

  11. Upward lightning observations from towers in Rapid City, South Dakota and comparison with National Lightning Detection Network data, 2004-2010

    Science.gov (United States)

    Warner, Tom A.; Cummins, Kenneth L.; Orville, Richard E.

    2012-10-01

    We report on upward lightning observations from ten tall towers (91-191 m) in Rapid City, South Dakota, USA and compare with National Lightning Detection Network (NLDN) data. A total of 81 upward flashes were observed from 2004-2010 using GPS time-stamped optical sensors, and in all but one case, visible flash activity preceded the development of the upward leaders. Time-correlated analysis showed that the NLDN recorded an event within 50 km of towers and within 500 ms prior to upward leader development from the tower(s) for 83% (67/81) of the upward flashes. A preceding positive cloud-to-ground stroke (+CG) was detected in 57% (46/81) of the cases, and a preceding positive intracloud flash (+IC) in 23% (19/81) of the cases. However, 8 of the 19 NLDN-indicated +IC events were actually +CG strokes based on optical observations. Preceding negative intracloud flashes (-IC) were recorded for 2% (2/81) of the cases. Analysis also showed that for 44% (36/81) of the upward flashes, the NLDN reported subsequent negative cloud-to-ground (-CG) strokes and/or -IC events at one or more tower locations. Of the 151 subsequent events, 70% (105/151) were -CG reports and 30% (46/151) were listed as -IC events. The geometric mean/median location accuracy and peak current for subsequent events were 194 m/206 m and -12.9 kA/-12.4 kA respectively. These correlated observations suggest that a majority of the upward lightning flashes were triggered by a preceding flash with the dominant triggering type being the +CG flash.

  12. Evaluation of Lightning Jumps as a Predictor of Severe Weather in the Northeastern United States

    Science.gov (United States)

    Eck, Pamela

    Severe weather events in the northeastern United States can be challenging to forecast, given how the evolution of deep convection can be influenced by complex terrain and the lack of quality observations in complex terrain. To supplement existing observations, this study explores using lightning to forecast severe convection in areas of complex terrain in the northeastern United States. A sudden increase in lightning flash rate by two standard deviations (2sigma), also known as a lightning jump, may be indicative of a strengthening updraft and an increased probability of severe weather. This study assesses the value of using lightning jumps to forecast severe weather during July 2015 in the northeastern United States. Total lightning data from the National Lightning Detection Network (NLDN) is used to calculate lightning jumps using a 2sigma lightning jump algorithm with a minimum threshold of 5 flashes min-1. Lightning jumps are used to predict the occurrence of severe weather, as given by whether a Storm Prediction Center (SPC) severe weather report occurred 45 min after a lightning jump in the same cell. Results indicate a high probability of detection (POD; 85%) and a high false alarm rate (FAR; 89%), suggesting that lightning jumps occur in sub-severe storms. The interaction between convection and complex terrain results in a locally enhanced updraft and an increased probability of severe weather. Thus, it is hypothesized that conditioning on an upslope variable may reduce the FAR. A random forest is introduced to objectively combine upslope flow, calculated using data from the High Resolution Rapid Refresh (HRRR), flash rate (FR), and flash rate changes with time (DFRDT). The random forest, a machine-learning algorithm, uses pattern recognition to predict a severe or non-severe classification based on the predictors. In addition to upslope flow, FR, and DFRDT, Next-Generation Radar (NEXRAD) Level III radar data was also included as a predictor to compare its

  13. Relationship between lightning and model simulated microphysical parameters over the central and eastern Mediterranean

    Directory of Open Access Journals (Sweden)

    D. K. Katsanos

    2009-10-01

    Full Text Available In this study the relationship between lightning and simulated microphysical parameters of clouds, is examined. In order to investigate such a relationship, a number of cases with significant lightning activity that occurred during the wet period of the year over the central and eastern Mediterranean have been selected, based on the lightning activity reported by the ZEUS lighting detection network, operated by the National Observatory of Athens. For the same cases, simulations with the non-hydrostatic MM5 model were performed with the aim of reproducing the dynamical and microphysical parameters associated with the weather systems that produced lightning. The analysis showed that the temporal distribution of convective rainfall is not well correlated with that of lightning, while on the contrary, the temporal distribution of the simulated concentrations of solid hydrometeors correlates well with lightning and there is also a general coincidence of their maxima. Further, it was shown that the best correlation was found during the development stage of the storms, while during the decay phase the number of lightning decreases much faster that the simulated concentrations of solid hydrometeors.

  14. Electrification processes and lightning generation in volcanic plumes—observations from recent eruptions

    Science.gov (United States)

    Van Eaton, A. R.; Smith, C. M.; Schneider, D. J.

    2017-12-01

    Lightning in volcanic plumes provides a promising way to monitor ash-producing eruptions and investigate their dynamics. Among the many methods of lightning detection are global networks of sensors that detect electromagnetic radiation in the very low frequency band (3-30 kHz), including the World Wide Lightning Location Network. These radio waves propagate thousands of kilometers at the speed of light, providing an opportunity for rapid detection of explosive volcanism anywhere in the world. Lightning is particularly valuable as a near real-time indicator of ash-rich plumes that are hazardous to aviation. Yet many fundamental questions remain. Under what conditions does electrical activity in volcanic plumes become powerful, detectable lightning? And conversely, can we use lightning to illuminate eruption processes and hazards? This study highlights recent observations from the eruptions of Redoubt (Alaska, 2009), Kelud (Indonesia, 2014), Calbuco (Chile, 2015), and Bogoslof (Alaska, 2017) to examine volcanic lighting from a range of eruption styles (Surtseyan to Plinian) and mass eruption rates from 10^5 to 10^8 kg/s. It is clear that lightning stroke-rates do not scale in a simple way with mass eruption rate or plume height across different eruptions. However, relative changes in electrical activity through individual eruptions relate to changes in eruptive intensity, ice content, and volcanic plume processes (fall vs. flow).

  15. The reciprocal relation between lightning and pollution and their impact over Kolkata, India.

    Science.gov (United States)

    Middey, Anirban; Chaudhuri, Sutapa

    2013-05-01

    Aerosol loading in the atmosphere can cause increased lightning flashes, and those lightning flashes produce NOX , which reacts in sun light to produce surface ozone. The present study deals with the effect of surface pollutants on premonsoon (April-May) lightning activity over the station Kolkata (22.65° N, 88.45° E). Seven-year (2004-2010) premonsoon thunderstorms data are taken for the study. Different parameters like aerosol optical depth and cloud top temperature from the Moderate Resolution Imaging Spectroradiometer satellite products along with lightning flash data from Tropical Rainfall Measuring Mission's (TRMM) Lightning Imaging Sensor are analyzed. Some surface pollution parameters like suspended particulate matter, particulate matter 10, nitrogen oxides (NOX), and surface ozone (O₃) data during the same period are taken account for clear understanding of their association with lightning activity. Heights of convective condensation level and lifting condensation level are collected from radiosonde observations to anticipate about cloud base. It is found that increased surface pollution in a near storm environment is related to increased lightning flash rate, which results in increased surface NOX and consequently increased surface ozone concentration over the station Kolkata.

  16. OIL OF PANDAN KELAPA HUTAN (Pandanus jiulianettii Martelli: PHYSICOCHEMICAL PROPERTIES, TOTAL PHENOLS, TOTAL CAROTENE, VITAMIN E AND ANTIOXIDANT ACTIVITY

    Directory of Open Access Journals (Sweden)

    LISYE IRIANA ZEBUA

    2018-01-01

    vitamin E and antioxidant activities of the forest coconut pandan oil (P. jiulianettii Martelli. extracted using an aluminum pan. Physicochemical character that been analyzed is specific gravity, iod value, saponification value, free fatty acid content, acid value and peroxide value. Total phenol, total carotene and vitamin E measured respectively using Folin-Ciocalteu method, spectrophotometry method and colorimetric methods. Antioxidant activities is measured using a method that called DPPH. The result shows the pandan coconut oil has 1,00059 of specific gravity, 65.87 g/100gr of iod, 201,28 mg/g of saponification, 4.26% of acid and 5.64 Meq/kg of peroxide. The content of total phenols, total carotene and vitamin E respectively are 48.55 ppm, 2.75 µg/g and 5.0303 mg/100g. The antioxidant IC50 measuring result shows the value is 45.83 mg/mL.

  17. Ball lightning dynamics and stability at moderate ion densities

    Science.gov (United States)

    Morrow, R.

    2017-10-01

    lightning. Additionally, ‘phantom plasma balls’ may well be generated and go unnoticed due to very low luminosity; luminous ball lightning may be the exception. Finally, the mechanism described here may also be active in the dynamics of bead lightning.

  18. Lightning Evolution In Two North Central Florida Summer Multicell Storms and Three Winter/Spring Frontal Storms

    Science.gov (United States)

    Caicedo, J. A.; Uman, M. A.; Pilkey, J. T.

    2018-01-01

    We present the first lightning evolution studies, via the Lightning Mapping Array (LMA) and radar, performed in North Central Florida. Parts of three winter/spring frontal storms (cold season) and two complete summer (warm season) multicell storms are studied. Storm parameters measured are as follows: total number of flashes, flash-type classification, first flashes, flash initiation altitude, flash initiation power, flash rate (flashes per minute), charge structure, altitude and temperature ranges of the inferred charge regions, atmospheric isotherm altitude, radar base reflectivity (dBZ), and radar echo tops (EET). Several differences were found between summer multicell and winter/spring frontal storms in North Central Florida: (1) in winter/spring storms, the range of altitudes that all charge regions occupy is up to 1 km lower in altitude than in summer storms, as are the 0°C, -10°C, and -20°C isotherms; (2) lightning activity in summer storms is highly correlated with changes in radar signatures, in particular, echo tops; and (3) the LMA average initiation power of all flash types in winter/frontal storms is about an order of magnitude larger than that for summer storms. In relation to storms in other geographical locations, North Central Florida seasonal storms were found to have similarities in most parameters studied with a few differences, examples in Florida being (1) colder initiation altitudes for intracloud flashes, (2) charge regions occupying larger ranges of atmospheric temperatures, and (3) winter/spring frontal storms not having much lightning activity in the stratiform region.

  19. Generation of Laboratory Ball Lightning

    Energy Technology Data Exchange (ETDEWEB)

    Oreshko, A G [Moscow Aviation Institute (State Technical University), Volokolamskoe shosse 4, 125871 Moscow (Russian Federation)

    2006-07-15

    The phenomenon of energy conversion in the streams of directed electrons and ions into electromagnetic radiation was found out experimentally and proved theoretically. The direct proofs of the domain mechanism of the charged particles acceleration and mechanism of ball lightning generation were obtained and the theoretical calculations were refined.

  20. A Conjecture Concerning Ball Lightning

    OpenAIRE

    Sturrock, P. A.

    2016-01-01

    There is at present no theory that can explain the curious properties of ball lightning. This suggests that we may not be using the most appropriate concepts. The concept of a 'parallel space' may point the way to a valid theory.

  1. Lightning protection of wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Soerensen, T.; Brask, M.H. [DEFU (Denmark); Jensen, F.V.; Raben, N. [SEAS (Denmark); Saxov, J. [Nordjyllandsvaerket (Denmark); Nielsen, L. [Vestkraft (Denmark); Soerensen, P.E. [Risoe National Lab. (Denmark)

    1999-03-01

    Lightning damage to wind turbines is a serious problem for Danish power companies, who have experienced some cases with very costly lightning damage and a large number of cases with minor damage. The most costly cases include one catastrophic damage to an entire wind turbine, and several cases of destruction of blades, main bearings, generators and control systems. Over the years there have been several hundreds of cases with minor damage - typically damage and interruptions of the control and communication systems, or the power systems. The Danish power companies anticipate that the lightning threat will be even bigger for the large off-shore wind turbine installations that are currently being planned in Denmark. Furthermore, it is known from the off-shore wind turbines at Vindeby in Denmark that the costs of inspection and particularly repair work must be expected to be much higher off-shore as compared to wind turbines on land. These considerations was the background for a two year project concerned with investigation of lighting damages and with the formulation of a DEFU Recommendation for lightning protection of wind turbines, which was published in January 1999. The project was funded by the Danish power companies Elsam, Eltra, Elkraft and by DEFU. (au)

  2. Measurement of RF lightning emissions

    Science.gov (United States)

    Lott, G. K., Jr.; Honnell, M. A.; Shumpert, T. H.

    1981-01-01

    A lightning radio emission observation laboratory is described. The signals observed and recorded include HF, VHF and UHF radio emissions, optical signature, electric field measurements, and thunder. The objectives of the station, the equipment used, and the recording methods are discussed.

  3. The Colorado Lightning Mapping Array

    Science.gov (United States)

    Rison, W.; Krehbiel, P. R.; Thomas, R. J.; Rodeheffer, D.; Fuchs, B.

    2012-12-01

    A fifteen station Lightning Mapping Array (LMA) was installed in northern Colorado in the spring of 2012. While the driving force for the array was to produce 3-dimensional lightning data to support the Deep Convective Clouds and Chemistry (DC3) Experiment (Barth, this conference), data from the array are being used for several other projects. These include: electrification studies in conjunction with the CSU CHILL radar (Lang et al, this conference); observations of the parent lightning discharges of sprites (Lyons et al, this conference); trying to detect upward discharges triggered by wind turbines, characterizing conditions in which aircraft flying through clouds produce discharges which can be detected by the LMA, and other opportunities, such as observations of lightning in pyrocumulus clouds produced by the High Park Fire west of Fort Collins, CO. All the COLMA stations are solar-powered, and use broadband cellular modems for data communications. This makes the stations completely self-contained and autonomous, allowing a station to be installed anywhere a cellular signal is available. Because most of the stations were installed well away from anthropogenic noise sources, the COLMA is very sensitive. This is evidenced by the numerous plane tracks detected in its the vicinity. The diameter, D, of the COLMA is about 100 km, significantly larger than other LMAs. Because the error in the radial distance r is proportional to (r/D)2, and the error in the altitude z is proportional to (z/D)2, the larger array diameter greatly expands the usable range of the COLMA. The COLMA is able to detect and characterize lighting flashes to a distance of about 350 km from the array center. In addition to a web-based display (lightning.nmt.edu/colma), geo-referenced images are produced and updated at one-minute intervals. These geo-referenced images can be used to overlay the real-time lightning data on Google Earth and other mapping software. These displays were used by the DC3

  4. Lightning Location Using Acoustic Signals

    Science.gov (United States)

    Badillo, E.; Arechiga, R. O.; Thomas, R. J.

    2013-05-01

    In the summer of 2011 and 2012 a network of acoustic arrays was deployed in the Magdalena mountains of central New Mexico to locate lightning flashes. A Times-Correlation (TC) ray-tracing-based-technique was developed in order to obtain the location of lightning flashes near the network. The TC technique, locates acoustic sources from lightning. It was developed to complement the lightning location of RF sources detected by the Lightning Mapping Array (LMA) developed at Langmuir Laboratory, in New Mexico Tech. The network consisted of four arrays with four microphones each. The microphones on each array were placed in a triangular configuration with one of the microphones in the center of the array. The distance between the central microphone and the rest of them was about 30 m. The distance between centers of the arrays ranged from 500 m to 1500 m. The TC technique uses times of arrival (TOA) of acoustic waves to trace back the location of thunder sources. In order to obtain the times of arrival, the signals were filtered in a frequency band of 2 to 20 hertz and cross-correlated. Once the times of arrival were obtained, the Levenberg-Marquardt algorithm was applied to locate the spatial coordinates (x,y, and z) of thunder sources. Two techniques were used and contrasted to compute the accuracy of the TC method: Nearest-Neighbors (NN), between acoustic and LMA located sources, and standard deviation from the curvature matrix of the system as a measure of dispersion of the results. For the best case scenario, a triggered lightning event, the TC method applied with four microphones, located sources with a median error of 152 m and 142.9 m using nearest-neighbors and standard deviation respectively.; Results of the TC method in the lightning event recorded at 18:47:35 UTC, August 6, 2012. Black dots represent the results computed. Light color dots represent the LMA data for the same event. The results were obtained with the MGTM station (four channels). This figure

  5. New Mission to Measure Global Lightning from the International Space Station (ISS)

    Science.gov (United States)

    Blakeslee, R. J.; Christian, H. J., Jr.; Mach, D. M.; Buechler, D. E.; Koshak, W. J.; Walker, T. D.; Bateman, M. G.; Stewart, M. F.; O'Brien, S.; Wilson, T. O.; Pavelitz, S. D.; Coker, C.

    2015-12-01

    Over the past 20 years, the NASA Marshall Space Flight Center, the University of Alabama in Huntsville, and their partners developed and demonstrated the effectiveness and value of space-based lightning observations as a remote sensing tool for Earth science research and applications, and, in the process, established a robust global lightning climatology. The observations included measurements from the Lightning Imaging Sensor (LIS) on the Tropical Rainfall Measuring Mission (TRMM) that acquired global observations of total lightning (i.e., intracloud and cloud-to-ground discharges) from November 1997 to April 2015 between 38° N/S latitudes, and its Optical Transient Detector predecessor that acquired observation from May 1995 to April 2000 over 75° N/S latitudes. In February 2016, as an exciting follow-on to these prior missions, a space-qualified LIS built as a flight-spare for TRMM will be delivered to the International Space Station (ISS) for a 2 year or longer mission, flown as a hosted payload on the Department of Defense Space Test Program-Houston 5 (STP-H5) mission. The LIS on ISS will continue observations of the amount, rate, and radiant energy of total lightning over the Earth. More specifically, LIS measures lightning during both day and night, with storm scale resolution (~4 km), millisecond timing, and high, uniform detection efficiency, without any land-ocean bias. Lightning is a direct and most impressive response to intense atmospheric convection. ISS LIS lightning observations will continue to provide important gap-filling inputs to pressing Earth system science issues across a broad range of disciplines. This mission will also extend TRMM time series observations, expand the latitudinal coverage to 54° latitude, provide real-time lightning data to operational users, espically over data sparse oceanic regions, and enable cross-sensor observations and calibrations that includes the new GOES-R Geostationary Lightning Mapper (GLM) and the Meteosat

  6. The TETRA-II Experiment to Observe Terrestrial Gamma Flashes at Ground Level - Analysis of Nearby Thunderstorm Activity and Comparison with Lightning Data

    Science.gov (United States)

    Smith, D.; Adams, C.; Cherry, M. L.; Al-Nussirat, S.; Bai, S.; Banadaki, Y.; Bitzer, P. M.; Hoffman, J.; Khosravi, E.; Legault, M.; Orang, M.; Pleshinger, D. J.; Rodriguez, R.; Trepanier, J. C.; Sunda-Meya, A.; Zimmer, N.

    2017-12-01

    Terrestrial gamma ray flashes (TGFs) are millisecond bursts of high-energy electrons propagated within the atmosphere. An upgraded version of the TGF and Energetic Thunderstorm Rooftop Array (TETRA-II) consists of an array of BGO scintillators to detect TGFs from thunderstorms at ground-level in four locations: the campus of Louisiana State University (LSU) in Baton Rouge, Louisiana; the campus of the University of Puerto Rico at Utuado, Puerto Rico, in conjunction with the already existing Puerto Rico Lightning Detection Network (PRLDN) of radio receivers; the Centro Nacional de Metrologia de Panama (CENAMEP) in Panama City, Panama; and the Severe Weather Institute and Radar & Lightning Laboratories in Huntsville, Alabama. The original TETRA-I array of NaI scintillators at LSU detected 37 millisecond-scale bursts of gamma-rays at energies of 50 keV-2 MeV associated with nearby (< 8 km) thunderstorms. TETRA-II began operation in May 2016 and now has approximately an order of magnitude greater sensitivity to individual events than TETRA-I. The ability to observe ground-level bursts from close to the source allows an analysis of the storm cells producing these events. An analysis of storms associated with TETRA II gamma-ray events is provided using NEXRAD Level II base-reflectivity scans to determine specific storm features before, during, and after the occurrence of each event. Louisiana events appear to occur within most major thunderstorm types, in particular as the cell is transitioning into the dissipating stage of evolution.

  7. In search for relationships between lightning and rainfall with a rectangular grid-box methodology

    Directory of Open Access Journals (Sweden)

    S. C. Michaelides

    2009-04-01

    Full Text Available The rainfall and lightning activity associated with three depressions which affected the area of Cyprus were studied in order to identify possible relationships between them. The lightning data were provided by the National Observatory of Athens, Greece, and were spatially and statistically related to the corresponding rainfall measurements from the rain gauge network of the Cyprus Meteorological Service. The study was carried out by using a rectangular grid-box methodology and various combinations of lightning and rainfall data filtering and time-lags were tested.

  8. Global Patterns of Lightning Properties Derived by OTD and LIS

    Science.gov (United States)

    Beirle, Steffen; Koshak, W.; Blakeslee, R.; Wagner, T.

    2014-01-01

    The satellite instruments Optical Transient Detector (OTD) and Lightning Imaging Sensor (LIS) provide unique empirical data about the frequency of lightning flashes around the globe (OTD), and the tropics (LIS), which 5 has been used before to compile a well received global climatology of flash rate densities. Here we present a statistical analysis of various additional lightning properties derived from OTD/LIS, i.e. the number of so-called "events" and "groups" per flash, as well as 10 the mean flash duration, footprint and radiance. These normalized quantities, which can be associated with the flash "strength", show consistent spatial patterns; most strikingly, oceanic flashes show higher values than continental flashes for all properties. Over land, regions with high (Eastern US) 15 and low (India) flash strength can be clearly identified. We discuss possible causes and implications of the observed regional differences. Although a direct quantitative interpretation of the investigated flash properties is difficult, the observed spatial patterns provide valuable information for the 20 interpretation and application of climatological flash rates. Due to the systematic regional variations of physical flash characteristics, viewing conditions, and/or measurement sensitivities, parametrisations of lightning NOx based on total flash rate densities alone are probably affected by regional biases.

  9. Characteristics of lightning flashes generating sprites above storms

    Directory of Open Access Journals (Sweden)

    Soula Serge

    2016-01-01

    Full Text Available Sprites are Transient Luminous Events (TLEs that can extend vertically from 40 to 90 km and horizontally over several tens of km to form clusters of individual or multiple column or/and carrot-shaped luminous elements. They can even extend over more than 100 km in the form of sequential luminous emissions that are called “dancing sprites”. Their optical detection and other parameters describing the storm and the lightning activity associated allow us to understand the conditions of their production and their links with the lightning activity. Our observations confirm some characteristics of the sprites and put forward others: (i the sprites are essentially produced above the stratiform region of the Mesoscale Convective Systems after positive cloud-to-ground lightning flashes that produce large Charge Moment Change (CMC, with a shorter delay if the impulsive CMC (iCMC is larger. (ii The dancing sprites reflect the timing and the location of the successive lightning strokes that generate them. (iii The sprite elements can be shifted from the stroke location when their delay is large. (iv Bright sprites produce current signatures in ELF radiation a few milliseconds (<5 ms after the positive strokes that generate them.

  10. Lightning Injury is a disaster in Bangladesh? - Exploring its magnitude and public health needs.

    Science.gov (United States)

    Biswas, Animesh; Dalal, Koustuv; Hossain, Jahangir; Ul Baset, Kamran; Rahman, Fazlur; Rahman Mashreky, Saidur

    2016-01-01

    Background: Lightning injury is a global public health issue. Low and middle-income countries in the tropical and subtropical regions of the world are most affected by lightning. Bangladesh is one of the countries at particular risk, with a high number of devastating lightning injuries in the past years, causing high mortality and morbidity. The exact magnitude of the problem is still unknown and therefore this study investigates the epidemiology of lightning injuries in Bangladesh, using a national representative sample. Methods: A mixed method was used. The study is based on results from a nationwide cross-sectional survey performed in 2003 in twelve randomly selected districts. In the survey, a total of 819,429 respondents from 171,336 households were interviewed using face-to-face interviews. In addition, qualitative information was obtained by reviewing national and international newspaper reports of lightning injuries sustained in Bangladesh between 13 and 15 May 2016. Results: The annual mortality rate was 3.661 (95% CI 0.9313-9.964) per 1,000,000 people. The overall incidence of lightning injury was 19.89/100,000 people. Among the victims, 60.12% (n=98) were males and 39.87% (n=65) were females. Males were particularly vulnerable, with a 1.46 times increased risk compared with females (RR 1.46, 95% CI 1.06-1.99). Rural populations were more vulnerable, with a 8.73 times higher risk, than urban populations (RR 8.73, 95% CI 5.13-14.86). About 43% of injuries occurred between 12 noon and 6 pm. The newspapers reported 81 deaths during 2 days of electric storms in 2016. Lightning has been declared a natural disaster in Bangladesh. Conclusions: The current study indicates that lightning injuries are a public health problem in Bangladesh. The study recommends further investigations to develop interventions to reduce lightning injuries, mortality and related burden in Bangladesh.

  11. On the Relationship between Observed NLDN Lightning ...

    Science.gov (United States)

    Lightning-produced nitrogen oxides (NOX=NO+NO2) in the middle and upper troposphere play an essential role in the production of ozone (O3) and influence the oxidizing capacity of the troposphere. Despite much effort in both observing and modeling lightning NOX during the past decade, considerable uncertainties still exist with the quantification of lightning NOX production and distribution in the troposphere. It is even more challenging for regional chemistry and transport models to accurately parameterize lightning NOX production and distribution in time and space. The Community Multiscale Air Quality Model (CMAQ) parameterizes the lightning NO emissions using local scaling factors adjusted by the convective precipitation rate that is predicted by the upstream meteorological model; the adjustment is based on the observed lightning strikes from the National Lightning Detection Network (NLDN). For this parameterization to be valid, the existence of an a priori reasonable relationship between the observed lightning strikes and the modeled convective precipitation rates is needed. In this study, we will present an analysis leveraged on the observed NLDN lightning strikes and CMAQ model simulations over the continental United States for a time period spanning over a decade. Based on the analysis, new parameterization scheme for lightning NOX will be proposed and the results will be evaluated. The proposed scheme will be beneficial to modeling exercises where the obs

  12. Modern concepts of treatment and prevention of lightning injuries.

    Science.gov (United States)

    Edlich, Richard F; Farinholt, Heidi-Marie A; Winters, Kathryne L; Britt, L D; Long, William B

    2005-01-01

    Lightning is the second most common cause of weather-related death in the United States. Lightning is a natural atmospheric discharge that occurs between regions of net positive and net negative electric charges. There are several types of lightning, including streak lightning, sheet lightning, ribbon lightning, bead lightning, and ball lightning. Lightning causes injury through five basic mechanisms: direct strike, flash discharge (splash), contact, ground current (step voltage), and blunt trauma. While persons struck by lightning show evidence of multisystem derangement, the most dramatic effects involve the cardiovascular and central nervous systems. Cardiopulmonary arrest is the most common cause of death in lightning victims. Immediate resuscitation of people struck by lightning greatly affects the prognosis. Electrocardiographic changes observed following lightning accidents are probably from primary electric injury or burns of the myocardium without coronary artery occlusion. Lightning induces vasomotor spasm from direct sympathetic stimulation resulting in severe loss of pulses in the extremities. This vasoconstriction may be associated with transient paralysis. Damage to the central nervous system accounts for the second most debilitating group of injuries. Central nervous system injuries from lightning include amnesia and confusion, immediate loss of consciousness, weakness, intracranial injuries, and even brief aphasia. Other organ systems injured by lightning include the eye, ear, gastrointestinal system, skin, and musculoskeletal system. The best treatment of lightning injuries is prevention. The Lightning Safety Guidelines devised by the Lightning Safety Group should be instituted in the United States and other nations to prevent these devastating injuries.

  13. Evaluation of antioxidant activity, total phenolics, total flavonoids and LC-MS/MS characterisation of phenolic constituents in Stachys lavandulifolia.

    Science.gov (United States)

    Rahimi Khoigani, Soroush; Rajaei, Ahmad; Goli, Sayed Amir Hossein

    2017-02-01

    The aim of this study was to evaluate phenolics profile and antioxidant activity of Stachys lavandulifolia. Total phenolics (TP), total flavonoids (TF), DPPH• assay (IC50), ferric ion reducing antioxidant power (FRAP) and total antioxidant capacity (TAC) of the methanolic extract were measured. The content of TP, TF, IC50, FRAP and TAC, were obtained as 16.59 gallic acid equiv./g dry matter (DM), 4.48 mg quercetin equiv./g DM, 2.07 (μg/mL), 0.014 (absorbance/mg phenolic) and 14.61 (mg BHT equiv./g DM), respectively. The results showed that S. lavandulifolia, compared to other species of Stachys, had moderate TP content with desirable antioxidant activity. Subsequently, 59 various phenolic compounds were identified and confirmed in the methanolic extract of S. lavandulifolia using high mass accuracy by MS2 experiments. The compounds consisted of 6 hydroxybenzoic acids and hydroxybenzoic aldehydes, 9 hydroxycinnamic acids, 1 coumarin, 32 flavonoids, 3 lignans, 2 stilbenes, 3 tannins and 3 other phenolics.

  14. Lightning Attachment Estimation to Wind Turbines by Utilizing Lightning Location Systems

    DEFF Research Database (Denmark)

    Vogel, Stephan; Holbøll, Joachim; Lopez, Javier

    2016-01-01

    The goal of a lightning exposure assessment is to identify the number, type and characteristics of lightning discharges to a certain structure. There are various Lightning Location System (LLS) technologies available, each of them are characterized by individual performance characteristics....... In this work, these technologies are reviewed and evaluated in order to obtain an estimation of which technologies are eligible to perform a lightning assessment to wind turbines. The results indicate that ground-based mid-range low frequency (LF) LLS systems are most qualified since they combine a wide...... coverage with a good accuracy for downward lightning. Furthermore, advances in the technology indicate the detection of certain upward lightning events. A correlation between the size of the uncertainty ellipse and the peak current of the lightning detections is presented. Furthermore, lightning data from...

  15. An Intrinsic Fiber-Optic Sensor for Structure Lightning Current Measurement

    Science.gov (United States)

    Nguyen, Truong X.; Ely, Jay J.; Szatkowski, George N.; Mata, Carlos T.; Mata, Angel. G.; Snyder, Gary P.

    2014-01-01

    An intrinsic optical-fiber sensor based on Faraday Effect is developed that is highly suitable for measuring lightning current on aircraft, towers and complex structures. Originally developed specifically for aircraft installations, it is light-weight, non-conducting, structure conforming, and is immune to electromagnetic interference, hysteresis and saturation. It can measure total current down to DC. When used on lightning towers, the sensor can help validate other sensors and lightning detection network measurements. Faraday Effect causes light polarization to rotate when the fiber is exposed to a magnetic field in the direction of light propagation. Thus, the magnetic field strength can be determined from the light polarization change. By forming closed fiber loops and applying Ampere's law, measuring the total light rotation yields the total current enclosed. A broadband, dual-detector, reflective polarimetric scheme allows measurement of both DC component and AC waveforms with a 60 dB dynamic range. Two systems were built that are similar in design but with slightly different sensitivities. The 1310nm laser system can measure 300 A - 300 kA, and has a 15m long sensing fiber. It was used in laboratory testing, including measuring current on an aluminum structure simulating an aircraft fuselage or a lightning tower. High current capabilities were demonstrated up to 200 kA at a lightning test facility. The 1550nm laser system can measure 400 A - 400 kA and has a 25m fiber length. Used in field measurements, excellent results were achieved in the summer of 2012 measuring rocket-triggered lightning at the International Center for Lightning Research and Testing (ICLRT), Camp Blanding, Florida. In both systems increased sensitivity can be achieved with multiple fiber loops. The fiber optic sensor provides many unique capabilities not currently possible with traditional sensors. It represents an important new tool for lightning current measurement where low weight

  16. Method to determine the activity concentration and total activity of radioactive waste; Metodo para determinar la concentracion de actividad y actividad total de desechos radiactivos

    Energy Technology Data Exchange (ETDEWEB)

    Angeles C, A

    2001-02-15

    A characteristic system of radioactive waste is described to determine the concentration of radionuclides activity and the total activity of bundles of radioactive waste. The system this integrated by three subsystems: - Elevator of drums. - Electromechanics. - Gamma spectroscopy. In the system it is analyzed waste of issuing gamma specifically, and this designed for materials of relative low density and it analyzes materials of cylindrical recipients.

  17. Lightning attachment process to common buildings

    Science.gov (United States)

    Saba, M. M. F.; Paiva, A. R.; Schumann, C.; Ferro, M. A. S.; Naccarato, K. P.; Silva, J. C. O.; Siqueira, F. V. C.; Custódio, D. M.

    2017-05-01

    The physical mechanism of lightning attachment to grounded structures is one of the most important issues in lightning physics research, and it is the basis for the design of the lightning protection systems. Most of what is known about the attachment process comes from leader propagation models that are mostly based on laboratory observations of long electrical discharges or from observations of lightning attachment to tall structures. In this paper we use high-speed videos to analyze the attachment process of downward lightning flashes to an ordinary residential building. For the first time, we present characteristics of the attachment process to common structures that are present in almost every city (in this case, two buildings under 60 m in São Paulo City, Brazil). Parameters like striking distance and connecting leaders speed, largely used in lightning attachment models and in lightning protection standards, are revealed in this work.Plain Language SummarySince the time of Benjamin Franklin, no one has ever recorded high-speed video images of a lightning connection to a common building. It is very difficult to do it. Cameras need to be very close to the structure chosen to be observed, and long observation time is required to register one lightning strike to that particular structure. Models and theories used to determine the zone of protection of a lightning rod have been developed, but they all suffer from the lack of field data. The submitted manuscript provides results from high-speed video observations of lightning attachment to low buildings that are commonly found in almost every populated area around the world. The proximity of the camera and the high frame rate allowed us to see interesting details that will improve the understanding of the attachment process and, consequently, the models and theories used by lightning protection standards. This paper also presents spectacular images and videos of lightning flashes connecting lightning rods that

  18. Utilizing Four Dimensional Lightning and Dual-Polarization Radar to Develop Lightning Initiation Forecast Guidance

    Science.gov (United States)

    2015-03-26

    lightning based on size and composite Z alone. Since the focus was airmass thunderstorms, any days with complex areas or lines of thunder - storms...Doppler radar signatures of developing thunder - storms and their potential to indicate the onset of cloud-to-ground lightning . Mon. Wea. Rev., 122...UTILIZING FOUR DIMENSIONAL LIGHTNING AND DUAL-POLARIZATION RADAR TO DEVELOP LIGHTNING INITIATION FORECAST GUIDANCE THESIS Andrew J. Travis, Captain

  19. An Integrated 0-1 Hour First-Flash Lightning Nowcasting, Lightning Amount and Lightning Jump Warning Capability

    Science.gov (United States)

    Mecikalski, John; Jewett, Chris; Carey, Larry; Zavodsky, Brad; Stano, Geoffrey; Chronis, Themis

    2015-01-01

    Using satellite-based methods that provide accurate 0-1 hour convective initiation (CI) nowcasts, and rely on proven success coupling satellite and radar fields in the Corridor Integrated Weather System (CIWS; operated and developed at MIT-Lincoln Laboratory), to subsequently monitor for first-flash lightning initiation (LI) and later period lightning trends as storms evolve. Enhance IR-based methods within the GOES-R CI Algorithm (that must meet specific thresholds for a given cumulus cloud before the cloud is considered to have an increased likelihood of producing lightning next 90 min) that forecast LI. Integrate GOES-R CI and LI fields with radar thresholds (e.g., first greater than or equal to 40 dBZ echo at the -10 C altitude) and NWP model data within the WDSS-II system for LI-events from new convective storms. Track ongoing lightning using Lightning Mapping Array (LMA) and pseudo-Geostationary Lightning Mapper (GLM) data to assess per-storm lightning trends (e.g., as tied to lightning jumps) and outline threat regions. Evaluate the ability to produce LI nowcasts through a "lightning threat" product, and obtain feedback from National Weather Service forecasters on its value as a decision support tool.

  20. Lightning effects on the NASA F-8 digital-fly-by-wire airplane

    Science.gov (United States)

    Plumer, J. A.; Fisher, F. A.; Walko, L. C.

    1975-01-01

    The effects of lightning on a Digital Fly-By-Wire (DFBW)aircraft control system were investigated. The aircraft was a NASA operated F-8 fitted with a modified Apollo guidance computer. Current pulses similar in waveshape to natural lightning, but lower in amplitude, were injected into the aircraft. Measurements were made of the voltages induced on the DFBW circuits, the total current induced on the bundles of wires, the magnetic field intensity inside the aircraft, and the current density on the skin of the aircraft. Voltage measurements were made in both the line-to-ground and line-to-line modes. Voltages measured at the non-destructive test level were then scaled upward to determine how much would be produced by actual lightning. A 200,000 ampere severe lightning flash would produce between 40 and 2000 volts in DFBW circuits. Some system components are expected to be vulnerable to these voltages.

  1. Description of an aircraft lightning and simulated nuclear electromagnetic pulse (NEMP) threat based on experimental data

    Science.gov (United States)

    Rustan, Pedro L., Jr.

    1987-01-01

    Lightning data obtained by measuring the surface electromagnetic fields on a CV-580 research aircraft during 48 lightning strikes between 1500 and 18,000 feet in central Florida during the summers of 1984 and 1985, and nuclear electromagnetic pulse (NEMP) data obtained by surface electromagnetic field measurements using a 1:74 CV-580 scale model, are presented. From one lightning event, maximum values of 3750 T/s for the time rate of change of the surface magnetic flux density, and 4.7 kA for the peak current, were obtained. From the simulated NEMP test, maximum values of 40,000 T/s for the time rate of change of the surface magnetic flux density, and 90 A/sq m for the total normal current density, were found. The data have application to the development of a military aircraft lightning/NEMP standard.

  2. Relativistic-microwave theory of ball lightning

    Science.gov (United States)

    Wu, H.-C.

    2016-06-01

    Ball lightning, a fireball sometimes observed during lightnings, has remained unexplained. Here we present a comprehensive theory for the phenomenon: At the tip of a lightning stroke reaching the ground, a relativistic electron bunch can be produced, which in turn excites intense microwave radiation. The latter ionizes the local air and the radiation pressure evacuates the resulting plasma, forming a spherical plasma bubble that stably traps the radiation. This mechanism is verified by particle simulations. The many known properties of ball lightning, such as the occurrence site, relation to the lightning channels, appearance in aircraft, its shape, size, sound, spark, spectrum, motion, as well as the resulting injuries and damages, are also explained. Our theory suggests that ball lighting can be created in the laboratory or triggered during thunderstorms. Our results should be useful for lightning protection and aviation safety, as well as stimulate research interest in the relativistic regime of microwave physics.

  3. Electric charge of a lightning ball

    Science.gov (United States)

    Grigor'ev, A. I.; Shiryaeva, S. O.; Petrushov, N. A.

    2016-09-01

    The electric charge of a lightning ball is found by comparing the electrohydrodynamic stabilities of a charged drop in an electrostatic suspension and a lightning ball floating in a superposition of the gravitational field and the surface electric field. It has been assumed that the electric field strength at the surface is limited by a breakdown value. For a lightning ball radius of 15 cm, its charge is estimated as several microcoulombs. Accordingly, the density of electrostatic energy accumulated in the lightning ball is on the order of one-hundredth of a joule per square centimeter. The density of the material that constitutes the lightning ball has been estimated for the case when the electric field strength at the site of its origination is several times higher than that in fine weather. The density of the lightning ball turns out to differ from that of air by only a few percents.

  4. Relativistic-microwave theory of ball lightning.

    Science.gov (United States)

    Wu, H-C

    2016-06-22

    Ball lightning, a fireball sometimes observed during lightnings, has remained unexplained. Here we present a comprehensive theory for the phenomenon: At the tip of a lightning stroke reaching the ground, a relativistic electron bunch can be produced, which in turn excites intense microwave radiation. The latter ionizes the local air and the radiation pressure evacuates the resulting plasma, forming a spherical plasma bubble that stably traps the radiation. This mechanism is verified by particle simulations. The many known properties of ball lightning, such as the occurrence site, relation to the lightning channels, appearance in aircraft, its shape, size, sound, spark, spectrum, motion, as well as the resulting injuries and damages, are also explained. Our theory suggests that ball lighting can be created in the laboratory or triggered during thunderstorms. Our results should be useful for lightning protection and aviation safety, as well as stimulate research interest in the relativistic regime of microwave physics.

  5. Lightning transient analysis in wind turbine blades

    DEFF Research Database (Denmark)

    Candela Garolera, Anna; Holbøll, Joachim; Madsen, Søren Find

    2013-01-01

    The transient behavior of lightning surges in the lightning protection system of wind turbine blades has been investigated in this paper. The study is based on PSCAD models consisting of electric equivalent circuits with lumped and distributed parameters involving different lightning current...... waveforms. The aim of the PSCAD simulations is to study the voltages induced by the lightning current in the blade that may cause internal arcing. With this purpose, the phenomenon of current reflections in the lightning down conductor of the blade and the electromagnetic coupling between the down conductor...... and other internal conductive elements of the blade is studied. Finally, several methods to prevent internal arcing are discussed in order to improve the lightning protection of the blade....

  6. Detecting Anthropogenic Impacts on Lightning: Is There an Obvious Signal?

    Science.gov (United States)

    Petersen, Walter A.; Carey, L. D.

    2009-01-01

    Bell et al. inferred the presence of increased (decreased) summer rainfall and storm heights over the southern tier (off the east coast) of the continental U.S. (CONUS) during the midweek. Amongst other data sources, the Bell et al. study employed Tropical Rainfall Measurement Mission (TRMM) passive microwave and precipitation radar data to reach these conclusions. Importantly, to explain the midweek increases in rainfall and storm echo top heights Bell et al. invoked the presence of anthropogenic influences via increased aerosol loading present in the middle of the work week. Conversely, Schultz et al. argue against the Bell et al. findings, noting that no significant trend in rainfall (amount or occurrence) can be detected in rain gauge data collected from 219 surface observing stations over a 42 year period. Based on previously suggested impacts of enhanced aerosol concentrations on precipitation microphysics and in particular, the ice phase, the results of Bell et al. suggest that in addition to the rainfall signal there may be a detectable response in lightning frequency (to the extent that the aerosol hypothesis invoked is valid). This study examines TRMM Lightning Imaging Sensor observations to detect both daily increases and decreases of lightning over the CONUS and neighboring ocean regions and further examines the possibility (through observations) of systematic direct impacts on lightning activity associated with large city locations.

  7. Observations of simultaneous upward lightning leaders from multiple tall structures

    Science.gov (United States)

    Warner, Tom A.

    2012-11-01

    We present high-speed camera observations (up to 7200 images per second) and correlated electric field measurements of upward lightning leaders initiated simultaneously from multiple tall towers. Four towers spanning a horizontal distance of 2.9 km and ranging in height from 121 to 191 m, developed upward leaders following a nearby positive cloud-to-ground (+ CG) flash on 7/16/09 UT in Rapid City, South Dakota, USA during the summer thunderstorm season. The optical and electric field observations suggest that all four upward propagating leaders were positive polarity (i.e., upward negative lightning) and initiated simultaneously approximately 2 ms following the + CG return stroke. There was significant intracloud flash activity prior to the return stroke, and upward leader initiation coincided with the passage of horizontally extensive in-cloud negative breakdown following the + CG return stroke. This observation supports the idea that downward positive cloud-to-ground lightning can trigger upward negative lightning from multiple tall objects. Specifically, the triggering component is an area of horizontally propagating negative breakdown following the + CG return stroke that influences a broad area resulting in simultaneous or near-simultaneous, positive polarity upward leader initiation from multiple tall objects.

  8. Objective Lightning Forecasting at Kennedy Space Center/Cape Canaveral Air Force Station using Cloud-to-Ground Lightning Surveillance System Data

    Science.gov (United States)

    Lambert, Winifred; Wheeler, Mark

    2004-01-01

    The 45th Weather Squadron (45 WS) forecasters at Cape Canaveral Air Force Station (CCAFS) in Florida include a probability of thunderstorm occurrence in their daily morning briefings. This information is used by personnel involved in determining the possibility of violating Launch Commit Criteria, evaluating Flight Rules for the Space Shuttle, and daily planning for ground operation activities on Kennedy Space Center (KSC)/CCAFS. Much of the current lightning probability forecast is based on a subjective analysis of model and observational data. The forecasters requested that a lightning probability forecast tool based on statistical analysis of historical warm-season (May - September) data be developed in order to increase the objectivity of the daily thunderstorm probability forecast. The tool is a set of statistical lightning forecast equations that provide a lightning occurrence probability for the day by 1100 UTC (0700 EDT) during the warm season. This study used 15 years (1989-2003) of warm season data to develop the objective forecast equations. The local CCAFS 1000 UTC sounding was used to calculate stability parameters for equation predictors. The Cloud-to-Ground Lightning Surveillance System (CGLSS) data were used to determine lightning occurrence for each day. The CGLSS data have been found to be more reliable indicators of lightning in the area than surface observations through local informal analyses. This work was based on the results from two earlier research projects. Everitt (1999) used surface observations and rawinsonde data to develop logistic regression equations that forecast the daily thunderstorm probability at CCAFS. The Everitt (1999) equations showed an improvement in skill over the Neumann-Pfeffer thunderstorm index (Neumann 1971), which uses multiple linear regression, and also persistence and climatology forecasts. Lericos et al. (2002) developed lightning distributions over the Florida peninsula based on specific flow regimes. The

  9. Using Flow Regime Lightning and Sounding Climatologies to Initialize Gridded Lightning Threat Forecasts for East Central Florida

    Science.gov (United States)

    Lambert, Winifred; Short, David; Volkmer, Matthew; Sharp, David; Spratt, Scott

    2007-01-01

    Each morning, the forecasters at the National Weather Service in Melbourne, FL (NWS MLB) produce an experimental cloud-to-ground (CG) lightning threat index map for their county warning area (CWA) that is posted to their web site (httl://www.srh.weather.gov/mlb/ghwo/lightning.shtml) . Given the hazardous nature of lightning in East Central Florida, especially during the warm season months of May September, these maps help users factor the threat of lightning, relative to their location, into their daily plans. The maps are color-coded in five levels from Very Low to Extreme, with threat level definitions based on the probability of lightning occurrence and the expected amount of CG activity. On a day in which thunderstorms are expected, there are typically two or more threat levels depicted spatially across the CWA. The locations of relative lightning threat maxima and minima often depend on the position and orientation of the low-level ridge axis, forecast propagation and interaction of sea/lake/outflow boundaries, expected evolution of moisture and stability fields, and other factors that can influence the spatial distribution of thunderstorms over the CWA. The lightning threat index maps are issued for the 24-hour period beginning at 1200 UTC each day with a grid resolution of 5 km x 5 km. Product preparation is performed on the AWIPS Graphical Forecast Editor (GFE), which is the standard NWS platform for graphical editing. Until recently, the forecasters created each map manually, starting with a blank map. To improve efficiency of the forecast process, NWS MLB requested that the Applied Meteorology Unit (AMU) create gridded warm season lightning climatologies that could be used as first-guess inputs to initialize lightning threat index maps. The gridded values requested included CG strike densities and frequency of occurrence stratified by synoptic-scale flow regime. The intent was to improve consistency between forecasters while allowing them to focus on the

  10. CAMEX-3 LIGHTNING INSTRUMENT PACKAGE (LIP) V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The CAMEX-3 Lightning Instrument Package (LIP) dataset contains electrical field measurements of lightning within storms studied during the Convection And Moisture...

  11. Relativistic-microwave theory of ball lightning

    OpenAIRE

    H.-C. Wu

    2016-01-01

    Ball lightning, a fireball sometimes observed during lightnings, has remained unexplained. Here we present a comprehensive theory for the phenomenon: At the tip of a lightning stroke reaching the ground, a relativistic electron bunch can be produced, which in turn excites intense microwave radiation. The latter ionizes the local air and the radiation pressure evacuates the resulting plasma, forming a spherical plasma bubble that stably traps the radiation. This mechanism is verified by partic...

  12. Assessment of uranium exposure from total activity and 234U:238U activity ratios in urine

    International Nuclear Information System (INIS)

    Nicholas, T.; Bingham, D.

    2011-01-01

    Radiation workers at Atomic Weapons Establishment (AWE) are monitored for uranium exposure by routine bioassay sampling (primarily urine sampling). However, the interpretation of uranium in urine and faecal results in terms of occupational intakes is difficult because of the presence of uranium due to intakes from environmental (dietary) sources. For uranium in urine data obtained using current analytical techniques at AWE, the mean, median and standard deviation of excreted uranium concentrations were 0.006, 0.002 and 0.012 μg per g creatinine, respectively. These values are consistent with what might be expected from local dietary intakes and the knowledge that occupational exposures at AWE are likely to be very low. However, some samples do exceed derived investigation levels (DILs), which have been set up taking account of the likely contribution from environmental sources. We investigate how the activity and isotopic composition of uranium in the diet affects the sensitivity of uranium in urine monitoring for occupational exposures. We conclude that DILs based on both total uranium in urine activity and also 234 U: 238 U ratios are useful given the likely variation in dietary contribution for AWE workers. Assuming a background excretion rate and that the enrichment of the likely exposure is known, it is possible to assess exposures using 234 U: 238 U ratios and/or total uranium activity. The health implications of internalised uranium, enriched to 235 U, centre on its nephrotoxicity; the DILs for bioassay samples at AWE are an order of magnitude below the conservative recommendations made by the literature. (authors)

  13. Time Correlations of Lightning Flash Sequences in Thunderstorms Revealed by Fractal Analysis

    Science.gov (United States)

    Gou, Xueqiang; Chen, Mingli; Zhang, Guangshu

    2018-01-01

    By using the data of lightning detection and ranging system at the Kennedy Space Center, the temporal fractal and correlation of interevent time series of lightning flash sequences in thunderstorms have been investigated with Allan factor (AF), Fano factor (FF), and detrended fluctuation analysis (DFA) methods. AF, FF, and DFA methods are powerful tools to detect the time-scaling structures and correlations in point processes. Totally 40 thunderstorms with distinguishing features of a single-cell storm and apparent increase and decrease in the total flash rate were selected for the analysis. It is found that the time-scaling exponents for AF (αAF) and FF (αFF) analyses are 1.62 and 0.95 in average, respectively, indicating a strong time correlation of the lightning flash sequences. DFA analysis shows that there is a crossover phenomenon—a crossover timescale (τc) ranging from 54 to 195 s with an average of 114 s. The occurrence of a lightning flash in a thunderstorm behaves randomly at timescales τc but shows strong time correlation at scales >τc. Physically, these may imply that the establishment of an extensive strong electric field necessary for the occurrence of a lightning flash needs a timescale >τc, which behaves strongly time correlated. But the initiation of a lightning flash within a well-established extensive strong electric field may involve the heterogeneities of the electric field at a timescale τc, which behave randomly.

  14. Using High Resolution Model Data to Improve Lightning Forecasts across Southern California

    Science.gov (United States)

    Capps, S. B.; Rolinski, T.

    2014-12-01

    Dry lightning often results in a significant amount of fire starts in areas where the vegetation is dry and continuous. Meteorologists from the USDA Forest Service Predictive Services' program in Riverside, California are tasked to provide southern and central California's fire agencies with fire potential outlooks. Logistic regression equations were developed by these meteorologists several years ago, which forecast probabilities of lightning as well as lightning amounts, out to seven days across southern California. These regression equations were developed using ten years of historical gridded data from the Global Forecast System (GFS) model on a coarse scale (0.5 degree resolution), correlated with historical lightning strike data. These equations do a reasonably good job of capturing a lightning episode (3-5 consecutive days or greater of lightning), but perform poorly regarding more detailed information such as exact location and amounts. It is postulated that the inadequacies in resolving the finer details of episodic lightning events is due to the coarse resolution of the GFS data, along with limited predictors. Stability parameters, such as the Lifted Index (LI), the Total Totals index (TT), Convective Available Potential Energy (CAPE), along with Precipitable Water (PW) are the only parameters being considered as predictors. It is hypothesized that the statistical forecasts will benefit from higher resolution data both in training and implementing the statistical model. We have dynamically downscaled NCEP FNL (Final) reanalysis data using the Weather Research and Forecasting model (WRF) to 3km spatial and hourly temporal resolution across a decade. This dataset will be used to evaluate the contribution to the success of the statistical model of additional predictors in higher vertical, spatial and temporal resolution. If successful, we will implement an operational dynamically downscaled GFS forecast product to generate predictors for the resulting

  15. The lightning climatology of South Africa

    OpenAIRE

    Morné Gijben

    2012-01-01

    In 2005, the South African Weather Service installed a state-of-the-art cloud-to-ground lightning detection network across the country. The data recorded by this network in 2006 was utilised in the development of an initial lightning climatology of South Africa. Until 2010, this climatology was based on data from a single year. This paper updates this climatology with the lightning data for the 2006–2010 period, which is the first actual lightning climatology by the South African Weather Serv...

  16. Geological Effects on Lightning Strike Distributions

    KAUST Repository

    Berdahl, J. Scott

    2016-05-16

    Recent advances in lightning detection networks allow for detailed mapping of lightning flash locations. Longstanding rumors of geological influence on cloud-to-ground (CG) lightning distribution and recent commercial claims based on such influence can now be tested empirically. If present, such influence could represent a new, cheap and efficient geophysical tool with applications in mineral, hydrothermal and oil exploration, regional geological mapping, and infrastructure planning. This project applies statistical analysis to lightning data collected by the United States National Lightning Detection Network from 2006 through 2015 in order to assess whether the huge range in electrical conductivities of geological materials plays a role in the spatial distribution of CG lightning. CG flash densities are mapped for twelve areas in the contiguous United States and compared to elevation and geology, as well as to the locations of faults, railroads and tall towers including wind turbines. Overall spatial randomness is assessed, along with spatial correlation of attributes. Negative and positive polarity lightning are considered separately and together. Topography and tower locations show a strong influence on CG distribution patterns. Geology, faults and railroads do not. This suggests that ground conductivity is not an important factor in determining lightning strike location on scales larger than current flash location accuracies, which are generally several hundred meters. Once a lightning channel is established, however, ground properties at the contact point may play a role in determining properties of the subsequent stroke.

  17. OLS ANALOG DERIVED LIGHTNING V1

    Data.gov (United States)

    National Aeronautics and Space Administration — Global lightning signatures from the Defense Meteorological Satellite Program (DMSP) Operational Linescan System (OLS) have been analyzed from the filmstrip imagery....

  18. Lightning Strike in Pregnancy With Fetal Injury.

    Science.gov (United States)

    Galster, Kellen; Hodnick, Ryan; Berkeley, Ross P

    2016-06-01

    Injuries from lightning strikes are an infrequent occurrence, and are only rarely noted to involve pregnant victims. Only 13 cases of lightning strike in pregnancy have been previously described in the medical literature, along with 7 additional cases discovered within news media reports. This case report presents a novel case of lightning-associated injury in a patient in the third trimester of pregnancy, resulting in fetal ischemic brain injury and long-term morbidity, and reviews the mechanics of lightning strikes along with common injury patterns of which emergency providers should be aware. Copyright © 2016 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.

  19. OPTICAL TRANSIENT DETECTOR (OTD) LIGHTNING V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The Optical Transient Detector (OTD) records optical measurements of global lightning events in the daytime and nighttime. The data includes individual point...

  20. Polymer-composite ball lightning.

    Science.gov (United States)

    Bychkov, V L

    2002-01-15

    Investigations into the state of ball lightning (BL) have been made, and both theory and experiments, related to so-called "polymer-composite" ball lightning, are presented. The properties of such a polymeric BL have been described and are that of a long-lived object capable of storing high energy. Results of experiments, starting with polymeric components in erosive gas discharge experiments, are described and discussed. The model of BL as a highly charged polymer-dielectric structure is described. According to this model BL appears as the result of the aggregation of natural polymers, such as lignin and cellulose, soot, polymeric silica and other natural dust particles. Its ability to glow is explained by the appearance over its perimeter of gas discharges near the highly charged BL surface, and electrical breakdown of some regions on the surface, consisting of polymerized and aggregated threads.

  1. Lightning Protection and Detection System

    Science.gov (United States)

    Dudley, Kenneth L. (Inventor); Szatkowski, George N. (Inventor); Woodard, Marie (Inventor); Nguyen, Truong X. (Inventor); Ely, Jay J. (Inventor); Wang, Chuantong (Inventor); Mielnik, John J. (Inventor); Koppen, Sandra V. (Inventor); Smith, Laura J. (Inventor)

    2017-01-01

    A lightning protection and detection system includes a non-conductive substrate material of an apparatus; a sensor formed of a conductive material and deposited on the non-conductive substrate material of the apparatus. The sensor includes a conductive trace formed in a continuous spiral winding starting at a first end at a center region of the sensor and ending at a second end at an outer corner region of the sensor, the first and second ends being open and unconnected. An electrical measurement system is in communication with the sensor and receives a resonant response from the sensor, to perform detection, in real-time, of lightning strike occurrences and damage therefrom to the sensor and the non-conductive substrate material.

  2. Indirect Lightning Safety Assessment Methodology

    Energy Technology Data Exchange (ETDEWEB)

    Ong, M M; Perkins, M P; Brown, C G; Crull, E W; Streit, R D

    2009-04-24

    Lightning is a safety hazard for high-explosives (HE) and their detonators. In the However, the current flowing from the strike point through the rebar of the building The methodology for estimating the risk from indirect lighting effects will be presented. It has two parts: a method to determine the likelihood of a detonation given a lightning strike, and an approach for estimating the likelihood of a strike. The results of these two parts produce an overall probability of a detonation. The probability calculations are complex for five reasons: (1) lightning strikes are stochastic and relatively rare, (2) the quality of the Faraday cage varies from one facility to the next, (3) RF coupling is inherently a complex subject, (4) performance data for abnormally stressed detonators is scarce, and (5) the arc plasma physics is not well understood. Therefore, a rigorous mathematical analysis would be too complex. Instead, our methodology takes a more practical approach combining rigorous mathematical calculations where possible with empirical data when necessary. Where there is uncertainty, we compensate with conservative approximations. The goal is to determine a conservative estimate of the odds of a detonation. In Section 2, the methodology will be explained. This report will discuss topics at a high-level. The reasons for selecting an approach will be justified. For those interested in technical details, references will be provided. In Section 3, a simple hypothetical example will be given to reinforce the concepts. While the methodology will touch on all the items shown in Figure 1, the focus of this report is the indirect effect, i.e., determining the odds of a detonation from given EM fields. Professor Martin Uman from the University of Florida has been characterizing and defining extreme lightning strikes. Using Professor Uman's research, Dr. Kimball Merewether at Sandia National Laboratory in Albuquerque calculated the EM fields inside a Faraday-cage type

  3. Saturn’s visible lightning, its radio emissions, and the structure of the 2009–2011 lightning storms

    OpenAIRE

    Dyudina, Ulyana A.; Ingersoll, Andrew P.; Ewald, Shawn P.; Porco, Carolyn C.; Fischer, Georg; Yair, Yoav

    2013-01-01

    Visible lightning on Saturn was first detected by the Cassini camera in 2009 at ∼35° South latitude. We report more lightning observations at ∼35° South later in 2009, and lightning in the 2010–2011 giant lightning storm at ∼35° North. The 2009 lightning is detected on the night side of Saturn in a broadband clear filter. The 2011 lightning is detected on the day side in blue wavelengths only. In other wavelengths the 2011 images lacked sensitivity to detect lightning, which leaves the lightn...

  4. How to create ball lightning

    Science.gov (United States)

    Golka, Robert K., Jr.

    1991-01-01

    Procedures are given on how to produce ball lightning. Necessary equipment includes a transformer of 150,000 watts capable of providing approximately 10,000 amperes at 15 volts, 60 cycles; thick one inch cables of stranded wire leading into a 3 by 4 by 1 foot plastic tank; a quarter inch thick 4 by 6 inch aluminum plate to be used as one of the discharge electrodes; and another electrode of heavy copper wire with the insulation stripped back 6 inches.

  5. Launch pad lightning protection effectiveness

    Science.gov (United States)

    Stahmann, James R.

    1991-01-01

    Using the striking distance theory that lightning leaders will strike the nearest grounded point on their last jump to earth corresponding to the striking distance, the probability of striking a point on a structure in the presence of other points can be estimated. The lightning strokes are divided into deciles having an average peak current and striking distance. The striking distances are used as radii from the points to generate windows of approach through which the leader must pass to reach a designated point. The projections of the windows on a horizontal plane as they are rotated through all possible angles of approach define an area that can be multiplied by the decile stroke density to arrive at the probability of strokes with the window average striking distance. The sum of all decile probabilities gives the cumulative probability for all strokes. The techniques can be applied to NASA-Kennedy launch pad structures to estimate the lightning protection effectiveness for the crane, gaseous oxygen vent arm, and other points. Streamers from sharp points on the structure provide protection for surfaces having large radii of curvature. The effects of nearby structures can also be estimated.

  6. Slow Lightning in Water Plasmoids

    Science.gov (United States)

    Stephan, Karl; Dumas, Shelby; McMinn, Jonathan

    2012-10-01

    Water plasmoids are produced when a capacitor is discharged into a cathode at the surface of a weakly conducting water electrolyte. The resulting plasma jet forms a glowing spherical plasmoid which persists in air for up to 0.3 s and resembles ball lightning in some respects. This study shows that during the plasmoid's formation stage, surface discharges with unusual characteristics carry the large instantaneous discharge current. The liquid-surface discharges have some characteristics of both conventional solid-surface discharges (branching, fractal structure) and glow discharges (approximately constant current density from the discharge plasma to the water surface over a wide range of current). Dynamically, the surface discharge resembles a two-dimensional version of a lightning leader, but develops at much lower speeds: a maximum of about 0.3 m/s for the surface discharges in this study, compared to lightning leader speeds of 100 to 100,000 m/s. The low conductivity of the water used (about 20 mS/m) means that the surface discharges are interacting with a resistive barrier, which allows a significant tangential electric field on the surface. High-speed photography of the discharges is supplemented by spectroscopic and other experimental studies.

  7. Cell Mergers and Their Impact on Cloud-to-Ground Lightning Over the Houston Area

    Science.gov (United States)

    Gauthier, Michael L.; Petersen, Walter A.; Carey, Lawrence D.

    2009-01-01

    A previous hypothesis advanced from observational studies such as METROMEX suggests that the intensity, frequency, and organization of cumulus convection may be impacted by the forcing of enhanced merger activity downstream of urban zones. A resulting corollary is that cities may exert an indirect anthropogenic forcing of parameters related to convection and associated phenomena such as lightning and precipitation. This paper investigates the urban merger hypothesis by examining the role of convective cell mergers on the existence and persistence of the Houston lightning "anomaly", a local maximum in cloud-to-ground (CG) lightning activity documented to exist over and east of Houston. Using eight summer seasons of peak columnar radar reflectivity, CG lightning data and a cell-tracking algorithm, a two-dimensional cell merger climatology is created for portions of eastern Texas and Louisiana. Results from the tracking and analysis of over 3.8 million cells indicate that merger-driven enhancements in convection induce a positive response (O 46%) in ground-flash densities throughout the domain, with areas of enhanced lightning typically being co-located with areas of enhanced merger activity. However, while mergers over the Houston area (relative to elsewhere in the domain) do result in more vigorous convective cells that produce larger CG flash densities, we find that CG lightning contributions due to mergers are distributed similarly throughout the domain. Hence while we demonstrate that cell mergers do greatly impact the production of lightning, the urban cell merger hypothesis does not uniquely explain the presence of a local lightning maximum near and downstream of Houston.

  8. Lightning Burns and Electrical Trauma in a Couple Simultaneously Struck by Lightning

    Directory of Open Access Journals (Sweden)

    Stephanie A. Eyerly-Webb

    2017-07-01

    Full Text Available More people are struck and killed by lightning each year in Florida than any other state in the United States. This report discusses a couple that was simultaneously struck by lightning while walking arm-in-arm. Both patients presented with characteristic lightning burns and were admitted for hemodynamic monitoring, serum labs, and observation and were subsequently discharged home. Despite the superficial appearance of lightning burns, serious internal electrical injuries are common. Therefore, lightning strike victims should be admitted and evaluated for cardiac arrhythmias, renal injury, and neurological sequelae.

  9. How much locomotive activity is needed for an active physical activity level: analysis of total step counts.

    Science.gov (United States)

    Ohkawara, Kazunori; Ishikawa-Takata, Kazuko; Park, Jong Hoon; Tabata, Izumi; Tanaka, Shigeho

    2011-11-24

    Although physical activity recommendations for public health have focused on locomotive activity such as walking and running, it is uncertain how much these activities contribute to overall physical activity level (PAL). The purpose of the present study was to determine the contribution of locomotive activity to PAL using total step counts measured in a calorimeter study. PAL, calculated as total energy expenditure divided by basal metabolic rate, was evaluated in 11 adult men using three different conditions for 24-hour human calorimeter measurements: a low-activity day (L-day) targeted at a low active level of PAL (1.45), and a high-frequency moderate activity day (M-day) or a high-frequency vigorous activity day (V-day) targeted at an active level of PAL (1.75). These subjects were permitted only light activities except prescribed activities. In a separate group of 41 adults, free-living PAL was evaluated using doubly-labeled water (DLW). In both experiments, step counts per day were also measured using an accelerometer. In the human calorimeter study, PAL and step counts were 1.42 ± 0.10 and 8,973 ± 543 steps/d (L-day), 1.82 ± 0.14 and 29,588 ± 1,126 steps/d (M-day), and 1.74 ± 0.15 and 23,755 ± 1,038 steps/d (V-day), respectively. In the DLW study, PAL and step counts were 1.73 ± 0.15 and 10,022 ± 2,605 steps/d, and there was no significant relationship between PAL and daily step counts. These results indicate that an enormous number of steps are needed for an active level of PAL if individuals extend physical activity-induced energy expenditure by only locomotive activity. Therefore, non-locomotive activity such as household activity should also play a significant role in increasing PAL under free-living conditions.

  10. How much locomotive activity is needed for an active physical activity level: analysis of total step counts

    Directory of Open Access Journals (Sweden)

    Ohkawara Kazunori

    2011-11-01

    Full Text Available Abstract Background Although physical activity recommendations for public health have focused on locomotive activity such as walking and running, it is uncertain how much these activities contribute to overall physical activity level (PAL. The purpose of the present study was to determine the contribution of locomotive activity to PAL using total step counts measured in a calorimeter study. Methods PAL, calculated as total energy expenditure divided by basal metabolic rate, was evaluated in 11 adult men using three different conditions for 24-hour human calorimeter measurements: a low-activity day (L-day targeted at a low active level of PAL (1.45, and a high-frequency moderate activity day (M-day or a high-frequency vigorous activity day (V-day targeted at an active level of PAL (1.75. These subjects were permitted only light activities except prescribed activities. In a separate group of 41 adults, free-living PAL was evaluated using doubly-labeled water (DLW. In both experiments, step counts per day were also measured using an accelerometer. Results In the human calorimeter study, PAL and step counts were 1.42 ± 0.10 and 8,973 ± 543 steps/d (L-day, 1.82 ± 0.14 and 29,588 ± 1,126 steps/d (M-day, and 1.74 ± 0.15 and 23,755 ± 1,038 steps/d (V-day, respectively. In the DLW study, PAL and step counts were 1.73 ± 0.15 and 10,022 ± 2,605 steps/d, and there was no significant relationship between PAL and daily step counts. Conclusions These results indicate that an enormous number of steps are needed for an active level of PAL if individuals extend physical activity-induced energy expenditure by only locomotive activity. Therefore, non-locomotive activity such as household activity should also play a significant role in increasing PAL under free-living conditions.

  11. Anti-inflammatory effect, total polysaccharide, total phenolics content and antioxidant activity of the aqueous extract of three basidiomycetes

    Directory of Open Access Journals (Sweden)

    M. Vazirian

    2014-01-01

    Full Text Available Inflammation is a part of the non-specific immune response which occurs in reaction to any type of injury. Medicinal mushrooms have had application in various disorders including cancer, liver injuries, inflammation and diabetes. In the present study, the anti-inflammatory effects of the aqueous extracts of medicinal mushrooms (Fomes fomentarius, Ganoderma applanatum and Trametes hirsuta were evaluated using carrageenan method. In addition, total polysaccharide, total phenolics contents and the radical scavenging activity of the extracts have also been examined. Mushrooms were extracted with distilled water in 100 °C for 4 hours and then the extracts were freeze dried. Indomethacin was considered as the positive control in the anti-inflammatory evaluation. Polysaccharide contents of F. fomentarius, G. applanatum, and T. hirsuta extracts were assessed as 53.3±0.2, 31.7±0.03, and 19.1±0.6 glucose equivalent µg/100 µgEXT and total phenolic contents of them were successfully revealed as 9.9±0.2, 8.2±0.1, and 8.8±0.2 µgGAE/100 µgEXT, respectively. Furthermore, the IC50 values for F. fomentarius, G. applanatum, and T. hirsuta extracts in DPPH assay, were calculated as 90.9, 108.6, and 908.3 µg/mL, respectively. The results of the experiment showed that the extracts possessed potent anti-inflammatory effect which was comparable to indomethacin.

  12. Small increase of actual physical activity 6 months after total hip or knee arthroplasty

    NARCIS (Netherlands)

    I.B. de Groot (Ingrid); J.B.J. Bussmann (Hans); H.J. Stam (Henk); J.A.N. Verhaar (Jan)

    2008-01-01

    textabstractLimitation in daily physical activity is one of the reasons for total hip arthroplasty (THA) or total knee arthroplasty (TKA). However, studies of the effects of THA or TKA generally do not determine actual daily activity as part of physical functioning. We determined the effect of THA

  13. Forecasting Lightning Threat using Cloud-Resolving Model Simulations

    Science.gov (United States)

    McCaul, Eugene W., Jr.; Goodman, Steven J.; LaCasse, Katherine M.; Cecil, Daniel J.

    2008-01-01

    Two new approaches are proposed and developed for making time and space dependent, quantitative short-term forecasts of lightning threat, and a blend of these approaches is devised that capitalizes on the strengths of each. The new methods are distinctive in that they are based entirely on the ice-phase hydrometeor fields generated by regional cloud-resolving numerical simulations, such as those produced by the WRF model. These methods are justified by established observational evidence linking aspects of the precipitating ice hydrometeor fields to total flash rates. The methods are straightforward and easy to implement, and offer an effective near-term alternative to the incorporation of complex and costly cloud electrification schemes into numerical models. One method is based on upward fluxes of precipitating ice hydrometeors in the mixed phase region at the-15 C level, while the second method is based on the vertically integrated amounts of ice hydrometeors in each model grid column. Each method can be calibrated by comparing domain-wide statistics of the peak values of simulated flash rate proxy fields against domain-wide peak total lightning flash rate density data from observations. Tests show that the first method is able to capture much of the temporal variability of the lightning threat, while the second method does a better job of depicting the areal coverage of the threat. Our blended solution is designed to retain most of the temporal sensitivity of the first method, while adding the improved spatial coverage of the second. Exploratory tests for selected North Alabama cases show that, because WRF can distinguish the general character of most convective events, our methods show promise as a means of generating quantitatively realistic fields of lightning threat. However, because the models tend to have more difficulty in predicting the instantaneous placement of storms, forecasts of the detailed location of the lightning threat based on single

  14. A Comparative Study on the Positive Lightning Return Stroke Electric Fields in Different Meteorological Conditions

    Directory of Open Access Journals (Sweden)

    Chin-Leong Wooi

    2015-01-01

    Full Text Available Positive cloud-ground lightning is considerably more complex and less studied compared to the negative lightning. This paper aims to measure and characterize the significant parameters of positive return strokes electric field, namely, the zero-to-peak rise time, 10–90% rise time, slow front duration, fast transition rise time (10–90%, zero-crossing time, and opposite polarity overshoot relative to peak. To the best of the authors’ knowledge, this is the first time such detailed characteristics of positive lightning in Malaysia are thoroughly analyzed. A total of 41 positive lightning flashes containing 48 return strokes were analyzed. The average multiplicity is 1.2 strokes per flash. The majority of positive lightning was initiated from the primary positive charge rather than as a byproduct of in-cloud discharges. The cumulative probability distribution of rise time parameters, opposite polarity overshoot relative to peak, and slow front amplitude relative to peak are presented. A comparison between studies in four countries representing tropic, subtropic, and temperate regions was also carried out. Measured parameters in Florida, Sweden, and Japan are generally lower than those in Malaysia. Positive lightning occurrences in tropical regions should be further studied and analyzed to improve our current understanding on positive return strokes.

  15. Measured current and close electric field changes associated with the initiation of upward lightning from a tall tower

    Science.gov (United States)

    Zhou, Helin; Diendorfer, Gerhard; Thottappillil, Rajeev; Pichler, Hannes; Mair, Martin

    2012-04-01

    We examine in detail the simultaneous lightning current waveforms, close electric field changes, and lightning location system data for upward lightning discharges initiated from the Gaisberg Tower (GBT) from 2005 to 2009. Out of 205 upward flashes, most of them (87% or 179/205) were initiated from the tower top without any nearby preceding lightning activity (called "self-initiated"), whereas 26 upward flashes (13%) were initiated from the tower top with immediately preceding nearby lightning activity (called "nearby-lightning-triggered"), including 15 positive ground flashes, one negative ground flashes, and 10 cloud discharges. The possible reasons for self-initiated upward flashes dominating at the GBT could be the field enhancement due to the Gaisberg Mountain above the surrounding terrain and low altitude of charge region during non-convective season (September to March), since we note that self-initiated lightning at the GBT occurred predominantly (79% or 142/179) during non-convective season. On the other hand the majority (85% or 22/26) of nearby-lightning-triggered upward flashes at the GBT occurring during convective season (April to August) and 80 nearby-lightning-triggered upward flashes out of 81 upward flashes observed at the ten tall towers in Rapid City in South Dakota of USA occurring during summer seasons, could be due to the result of high altitude of charge region. The triggering flashes were detected to be within 1 and 18 km distance and the time intervals between them and upward lightning initiation are in the range of 0.3 to 90.7 ms.

  16. Lightning Discharges, Cosmic Rays and Climate

    Science.gov (United States)

    Kumar, Sanjay; Siingh, Devendraa; Singh, R. P.; Singh, A. K.; Kamra, A. K.

    2018-03-01

    The entirety of the Earth's climate system is continuously bombarded by cosmic rays and exhibits about 2000 thunderstorms active at any time of the day all over the globe. Any linkage among these vast systems should have global consequences. Numerous studies done in the past deal with partial links between some selected aspects of this grand linkage. Results of these studies vary from weakly to strongly significant and are not yet complete enough to justify the physical mechanism proposed to explain such links. This review is aimed at presenting the current understanding, based on the past studies on the link between cosmic ray, lightning and climate. The deficiencies in some proposed links are pointed out. Impacts of cosmic rays on engineering systems and the possible effects of cosmic rays on human health are also briefly discussed. Also enumerated are some problems for future work which may help in developing the grand linkage among these three vast systems.

  17. ASSESSMENT TO EFFECTIVENESS OF THE NEW EARLY STREAMER EMISSION LIGHTNING PROTECTION SYSTEM

    OpenAIRE

    A. Chen, Yen-Hong; Lin, Kai-Jan; M. Li, Yu-Chu

    2017-01-01

    A novel early streamer emission (ESE) lightning air terminal system is designed and fabricated. By comparing the intercepted artificial lightning striking numbers of the new ESE lightning protection device and the conventional lightning rod (CLR) lightning protection device in laboratory, the effectiveness of intercepting the artificial lightning strokes by the new ESE lightning protection device is superior to that by the conventional lightning rod lightning protection device. A modified Tes...

  18. Phenomenon of ball lightning and its outgrowths

    Energy Technology Data Exchange (ETDEWEB)

    Torchigin, V.P. [Institute of Informatics Problems, Russian Academy of Sciences, Nakhimovsky prospect 36/1, 119278 Moscow (Russian Federation)]. E-mail: v_torchigin@mail.ru; Torchigin, A.V. [Institute of Informatics Problems, Russian Academy of Sciences, Nakhimovsky prospect 36/1, 119278 Moscow (Russian Federation)

    2005-03-28

    New physical phenomena deduced from properties of ball lightning are considered under assumption that ball lightning is a light bubble comprising of a thin spherical layer of compressed air where an intense light circulates in all possible directions. Explanation of behavior of autonomous luminous objects produced at gas discharge is presented.

  19. When Lightning Strikes a Second Time

    Science.gov (United States)

    Allen, Kent

    2017-01-01

    The chances of lightning striking twice are infinitesimal, at best. What are the odds, in middle age, of being struck with a jarring bolt of figurative lightning, then a few months later being an eyewitness as the same sizzle in the sky jolts a group of students--those decision-makers of tomorrow? The author describes two experiences that proved…

  20. Lightning protecting materials used on radar system

    NARCIS (Netherlands)

    Blaj, M.A.; Damstra, Geert C.; Buesink, Frederik Johannes Karel; Leferink, Frank Bernardus Johannes

    2009-01-01

    Because of the extensive use in modern systems of very sensitive electronic components, lightning strikes does not represent only a threat, but something that cannot be neglected anymore and safety hazards caused by direct and indirect lightning to the aircraft or naval industry. Everyday new

  1. Lightning-caused fires in Central Spain

    DEFF Research Database (Denmark)

    Nieto Solana, Hector; Aguado, Inmaculada; García, Mariano

    2012-01-01

    a high occurrence. The research was conducted between May and September, which happens to be the most lightning-fire prone period in Spain, for a three year interval starting in 2002 up to 2004. A time-invariant model for lightning-caused fire occurrence was developed for each region at a spatial...

  2. Mathematical physics approaches to lightning discharge problems

    Science.gov (United States)

    Kyrala, A.

    1985-01-01

    Mathematical physics arguments useful for lightning discharge and generation problems are pursued. A soliton Ansatz for the lightning stroke is treated including a charge generation term which is the ultimate source for the phenomena. Equations are established for a partially ionized plasma inding the effects of pressure, magnetic field, electric field, gravitation, viscosity, and temperature. From these equations is then derived the non-stationary generalized Ohm's Law essential for describing field/current density relationships in the horizon channel of the lightning stroke. The discharge initiation problem is discussed. It is argued that the ionization rate drives both the convective current and electric displacement current to increase exponentially. The statistical distributions of charge in the thundercloud preceding a lightning dischage are considered. The stability of the pre-lightning charge distributions and the use of Boltzmann relaxational equations to determine them are discussed along with a covered impedance path provided by the aircraft.

  3. Progress towards a lightning ignition model for the Northern Rockies

    Science.gov (United States)

    Paul Sopko; Don Latham

    2010-01-01

    We are in the process of constructing a lightning ignition model specific to the Northern Rockies using fire occurrence, lightning strike, ecoregion, and historical weather, NFDRS (National Fire Danger Rating System), lightning efficiency and lightning "possibility" data. Daily grids for each of these categories were reconstructed for the 2003 fire season (...

  4. The Effect of Structured Exercise Intervention on Intensity and Volume of Total Physical Activity

    Directory of Open Access Journals (Sweden)

    Niko Wasenius

    2014-12-01

    Full Text Available This study aimed to investigate the effects of a 12-week structured exercise intervention on total physical activity and its subcategories. Twenty-three overweight or obese middle aged men with impaired glucose regulation were randomized into a 12-week Nordic walking group, a power-type resistance training group, and a non-exercise control group. Physical activity was measured with questionnaires before the intervention (1–4 weeks and during the intervention (1–12 weeks and was expressed in metabolic equivalents of task. No significant change in the volume of total physical activity between or within the groups was observed (p > 0.050. The volume of total leisure-time physical activity (structured exercises + non-structured leisure-time physical activity increased significantly in the Nordic walking group (p 0.050 compared to the control group. In both exercise groups increase in the weekly volume of total leisure-time physical activity was inversely associated with the volume of non-leisure-time physical activities. In conclusion, structured exercise intervention did not increase the volume of total physical activity. Albeit, endurance training can increase the volume of high intensity physical activities, however it is associated with compensatory decrease in lower intensity physical activities. To achieve effective personalized exercise program, individuality in compensatory behavior should be recognised.

  5. Semi-idealized modeling of lightning initiation related to vertical air motion and cloud microphysics

    Science.gov (United States)

    Wang, Fei; Zhang, Yijun; Zheng, Dong; Xu, Liangtao; Zhang, Wenjuan; Meng, Qing

    2017-10-01

    A three-dimensional charge-discharge numerical model is used, in a semi-idealized mode, to simulate a thunder-storm cell. Characteristics of the graupel microphysics and vertical air motion associated with the lightning initiation are revealed, which could be useful in retrieving charge strength during lightning when no charge-discharge model is available. The results show that the vertical air motion at the lightning initiation sites ( W ini) has a cubic polynomial correlation with the maximum updraft of the storm cell ( W cell-max), with the adjusted regression coefficient R 2 of approximately 0.97. Meanwhile, the graupel mixing ratio at the lightning initiation sites ( q g-ini) has a linear correlation with the maximum graupel mixing ratio of the storm cell ( q g-cell-max) and the initiation height ( z ini), with the coefficients being 0.86 and 0.85, respectively. These linear correlations are more significant during the middle and late stages of lightning activity. A zero-charge zone, namely, the area with very low net charge density between the main positive and negative charge layers, appears above the area of q g-cell-max and below the upper edge of the graupel region, and is found to be an important area for lightning initiation. Inside the zero-charge zone, large electric intensity forms, and the ratio of q ice (ice crystal mixing ratio) to q g (graupel mixing ratio) illustrates an exponential relationship to q g-ini. These relationships provide valuable clues to more accurately locating the high-risk area of lightning initiation in thunderstorms when only dual-polarization radar data or outputs from numerical models without charging/discharging schemes are available. The results can also help understand the environmental conditions at lightning initiation sites.

  6. Searching for possible effects on midlatitude sporadic E layer, caused by tropospheric lightning.

    Science.gov (United States)

    Barta, Veronika; Haldoupis, Christos; Sátori, Gabriella; Buresova, Dalia

    2016-07-01

    Thunderstorms in the troposphere may affect the overlying ionosphere through electrodynamic and/or neutral atmosphere wave coupling processes. For example, it is well known that lightning discharges may impact upper atmosphere through quasi-electrostatic fields and strong electromagnetic pulses, leading to transient luminous phenomena, such as sprites and elves, along with electron heating and ionization changes in the upper D and lower E-region ionosphere that have been detected in VLF transmissions propagating in the earth-ionosphere waveguide. On the other hand, mechanical coupling between the troposphere and the ionosphere may be caused by neutral atmosphere gravity waves which are known to have their origin in massive thunderstorms. The effects of troposphere-ionosphere coupling during thunderstorms, are not yet fully established and understood, therefore there is need for more correlative studies, for example by using concurrent ionospheric and lightning observations. In the present work an effort is made to investigate a possible relationship between tropospheric lighting and sporadic E layer, which are known to dominate at bottomside ionosphere and at middle latitudes during summer. For this, a correlative analysis was undertaken using lightning data obtained with the LINET lightning detection network in Central Europe, and E region ionospheric parameters (fmin, foE, foEs, fbEs) measured with the Pruhonice (50° N, 14.5° E) DPS-4D digisonde in the summer of 2009. For direct correlation with the digisonde data, the lightning activity was quantified every 15 minutes in coincidence with the measured ionogram parameters. In the search for relation between lightning and sporadic E, the digisonde observations during lightning were also compared with those taken during a number of tropospheric storm-free days in Pruhonice. The results of this correlative study did not provide evidence of significance that favors a relationship between tropospheric lightning and

  7. Total antioxidant activity and fiber content of select Florida-grown tropical fruits.

    Science.gov (United States)

    Mahattanatawee, Kanjana; Manthey, John A; Luzio, Gary; Talcott, Stephen T; Goodner, Kevin; Baldwin, Elizabeth A

    2006-09-20

    Fourteen tropical fruits from south Florida (red guava, white guava, carambola, red pitaya (red dragon), white pitaya (white dragon), mamey sapote, sapodilla, lychee, longan, green mango, ripe mango, green papaya, and ripe papaya) were evaluated for antioxidant activity, total soluble phenolics (TSP), total ascorbic acid (TAA), total dietary fiber (TDF), and pectin. ORAC (oxygen radical absorbance capacity) and DPPH (1,1-diphenyl-2-picrylhydrazyl, radical scavenging activity) assays were used to determine antioxidant activity. The TSP, ORAC, and DPPH ranged from 205.4 to 2316.7 g gallic acid equiv/g puree, pitaya (dragonfruit), lychee, and mamey sapote, these fruit being thus far uncharacterized in the literature.

  8. Accelerometer-Derived Total Activity Counts, Bouted Minutes of Moderate to Vigorous Activity, and Insulin Resistance: NHANES 2003-2006.

    Science.gov (United States)

    Boyer, William R; Wolff-Hughes, Dana L; Bassett, David R; Churilla, James R; Fitzhugh, Eugene C

    2016-10-20

    The objective of this study was to compare the associations of accelerometer-derived total activity counts per day and minutes of bouted moderate to vigorous physical activity (MVPA) with insulin resistance. The sample included 2,394 adults (aged ≥20 y) from the 2003-2006 National Health and Nutrition Examination Survey. Time spent in MVPA, measured by using 2 cutpoints (≥2,020 counts/min [MVPA 2,020 ] and ≥760 counts/min [MVPA 760 ]), was calculated for bouts of at least 8 to 10 minutes. Total activity counts per day reflects the total amount of activity across all intensities. Insulin resistance was measured via the homeostatic model assessment of insulin resistance (HOMA-IR) and the quantitative insulin sensitivity check index (QUICKI). Two nested regression models regressed HOMA-IR and QUICKI, respectively, on minutes of bouted MVPA and total activity counts per day. We used an adjusted Wald F statistic to illustrate strength of association. After adjustment for covariates, total activity counts per day was more strongly associated with both HOMA-IR (adjusted Wald F = 36.83 , P activity counts per day was more strongly associated with both HOMA-IR (adjusted Wald F = 13.64, P activity counts per day has stronger associations with insulin resistance compared with minutes of bouted MVPA. The most likely explanation is that total activity counts per day captures data on light physical activity and intermittent MVPA, both of which influence insulin resistance.

  9. The Lightning Nitrogen Oxides Model (LNOM): Status and Recent Applications

    Science.gov (United States)

    Koshak, William; Khan, Maudood; Peterson, Harold

    2011-01-01

    Improvements to the NASA Marshall Space Flight Center Lightning Nitrogen Oxides Model (LNOM) are discussed. Recent results from an August 2006 run of the Community Multiscale Air Quality (CMAQ) modeling system that employs LNOM lightning NOx (= NO + NO2) estimates are provided. The LNOM analyzes Lightning Mapping Array (LMA) data to estimate the raw (i.e., unmixed and otherwise environmentally unmodified) vertical profile of lightning NOx. The latest LNOM estimates of (a) lightning channel length distributions, (b) lightning 1-m segment altitude distributions, and (c) the vertical profile of NOx are presented. The impact of including LNOM-estimates of lightning NOx on CMAQ output is discussed.

  10. Evaluation of Product Algorithm Strategies for the Future Lightning Imager on MTG

    Science.gov (United States)

    Finke, U.; Grandell, J.

    2014-12-01

    The future European geostationary Meteosat Third Generation (MTG) will carry a lightning observation instrument - the Lightning Imager (LI), which will observe lightning in thunderstorm for the whole visible Earth disk with high temporal and spatial resolution. Its data will be of great benefit for nowcasting of lightning thread and severe weather, as well as for applications in lightning physics, chemistry and climatology. Primary data output of the instrument are the 'lightning events' corresponding to triggered pixels of the detector matrix. These primary data are processed into a set of products: hierarchically organized point data - groups and flashes, and various products of data accumulated over time and space bins. The algorithm strategies for generation of these level-2 products are evaluated in this contribution.The clustering of the lightning event data consists of two steps: i) pixel events are clustered in a group representing the optical pulse, and ii) the groups are clustered in a flash representing the lightning flash. The algorithm strategies for clustering are discussed and evaluated for the various algorithm parameters. The distance function and linkage criteria are formulated in time and space. For groups the criterion is immediate adjacency in time and space. For flashes the gap to the nearest neighbor in time and space have to be lower a threshold value. Examples and statistics of the application of the clustering algorithms are presented for LIS data and for proxy data.The second group of products accumulate the lightning point data in time (30s) and space (2km) intervals. The planned products are the accumulated flash number, flash area and flash radiance. All these products are created on a per flash bases using the pixel set for each flash. They are calculated on a grid which correspond cloud imager (FCI) grid on the same platform. The accumulated products represent an snapshot picture of the current lightning activity, valuable in

  11. An Evaluation of Lightning Flash Rate Parameterizations Based on Observations of Colorado Storms during DC3

    Science.gov (United States)

    Basarab, B.; Fuchs, B.; Rutledge, S. A.

    2013-12-01

    Predicting lightning activity in thunderstorms is important in order to accurately quantify the production of nitrogen oxides (NOx = NO + NO2) by lightning (LNOx). Lightning is an important global source of NOx, and since NOx is a chemical precursor to ozone, the climatological impacts of LNOx could be significant. Many cloud-resolving models rely on parameterizations to predict lightning and LNOx since the processes leading to charge separation and lightning discharge are not yet fully understood. This study evaluates predicted flash rates based on existing lightning parameterizations against flash rates observed for Colorado storms during the Deep Convective Clouds and Chemistry Experiment (DC3). Evaluating lightning parameterizations against storm observations is a useful way to possibly improve the prediction of flash rates and LNOx in models. Additionally, since convective storms that form in the eastern plains of Colorado can be different thermodynamically and electrically from storms in other regions, it is useful to test existing parameterizations against observations from these storms. We present an analysis of the dynamics, microphysics, and lightning characteristics of two case studies, severe storms that developed on 6 and 7 June 2012. This analysis includes dual-Doppler derived horizontal and vertical velocities, a hydrometeor identification based on polarimetric radar variables using the CSU-CHILL radar, and insight into the charge structure using observations from the northern Colorado Lightning Mapping Array (LMA). Flash rates were inferred from the LMA data using a flash counting algorithm. We have calculated various microphysical and dynamical parameters for these storms that have been used in empirical flash rate parameterizations. In particular, maximum vertical velocity has been used to predict flash rates in some cloud-resolving chemistry simulations. We diagnose flash rates for the 6 and 7 June storms using this parameterization and compare

  12. Using radar-derived parameters to forecast lightning cessation for nonisolated storms

    Science.gov (United States)

    Davey, Matthew J.; Fuelberg, Henry E.

    2017-03-01

    Lightning impacts operations at the Kennedy Space Center (KSC) and other outdoor venues leading to injuries, inconvenience, and detrimental economic impacts. This research focuses on cases of "nonisolated" lightning which we define as one cell whose flashes have ceased although it is still embedded in weak composite reflectivity (Z ≥ 15 dBZ) with another cell that is still producing flashes. The objective is to determine if any radar-derived parameters provide useful information about the occurrence of lightning cessation in remnant storms. The data set consists of 50 warm season (May-September) nonisolated storms near KSC during 2013. The research utilizes the National Lightning Detection Network, the second generation Lightning Detection and Ranging network, and polarized radar data. These data are merged and analyzed using the Warning Decision Support System-Integrated Information at 1 min intervals. Our approach only considers 62 parameters, most of which are related to the noninductive charging mechanism. They included the presence of graupel at various thermal altitudes, maximum reflectivity of the decaying storm at thermal altitudes, maximum connecting composite reflectivity between the decaying cell and active cell, minutes since the previous flash, and several others. Results showed that none of the parameters reliably indicated lightning cessation for even our restrictive definition of nonisolated storms. Additional research is needed before cessation can be determined operationally with the high degree of accuracy required for safety.

  13. An assessment of tailoring of lightning protection design requirements for a composite wing structure on a metallic aircraft

    Science.gov (United States)

    Harwood, T. L.

    1991-01-01

    The Navy A-6E aircraft is presently being modified with a new wing which uses graphite/epoxy structures and substructures around a titanium load-bearing structure. The ability of composites to conduct electricity is less than that of aluminum. This is cause for concern when the wing may be required to conduct large lightning currents. The manufacturer attempted to solve lightning protection issues by performing a risk assessment based on a statistical approach which allows relaxation of the wing lightning protection design levels over certain locations of the composite wing. A sensitivity study is presented designed to define the total risk of relaxation of the design levels.

  14. Lightning - Apollo to Shuttle. [case histories and spacecraft protection

    Science.gov (United States)

    Durrett, W. R.

    1976-01-01

    The history of lightning striking NASA spacecraft and the development of lightning protection systems is reviewed from the Apollo 12 flight, involving a lightning strike thirty six seconds after launch, to the present date. Particular attention is paid to problems that may arise in this field in the context of planning and implementing the Space Shuttle program. The lightning protection design for Apollo is described: a folding mast mounted on top of the hammerhead crane on top of the Launcher Umbilical Tower, with a lightning rod on top. The effect of lightning storms on the launches of Apollos 12 through 17 is examined, as is the effect of lightning in the Skylab program. The lightning problems encountered by the Apollo-Soyuz mission and by the two unmanned Viking launches to Mars are discussed. The Lightning Detection And Ranging system for detecting RF emission from lightning discharges is described.

  15. Secret of a ball lightning

    OpenAIRE

    Савич, Эдуард Владимирович

    2013-01-01

    Шаровая молния – явление природы, происходящее при ударе линейной молнии с ее воздействием тепловой и магнитной энергии, возникающей вокруг канала линейной молнии и в результате образующей из окружающего воздуха облако пара, переходящего под воздействием магнитного поля сегнетоэлектрическое состояние. A ball lightning is a natural phenomenon that occurs at a streak lightning stroke with its action by thermal and magnetic energy releasing around the streak lightning channel and transforming...

  16. Plasma theory of ball lightning

    Energy Technology Data Exchange (ETDEWEB)

    Ostapenko, V.I.; Tolpygo, K.B.

    1984-02-01

    The high-energy density inside the ball lightning is due to existence of intense plasma oscillations and high kinetic and potential energy of electron gas which form a pulsating ball vibrating relative to the nearly stationary ionic ball. At sublight velocities of electrons one can neglect the processes of their scattering and recombination. One obtains a relation between parameters of the plasma ball from the condition of equality of excess pressure of ions and that of Madelung forces. The high lifetime of the ball lighting is connected with small Landau damping for the longest wave vibrations.

  17. Spatial Variation of the Correlated Color Temperature of Lightning Channel

    OpenAIRE

    Shimoji, Nobuaki; Aoyama, Ryoma

    2014-01-01

    In present work, we propose the analysis method of lightning based on the color analysis. We analyzed the digital still images in which the cloud-to-ground (CG) and intracloud (IC) lightning flashes are shown. Applying some digital image processing techniques, we extracted lightning channels. Then, the correlated color temperature (CCT) of the extracted lightning channels was obtained by mapping digital pixels of the extracted lightning channels to CIE 1931 xy-chromaticity diagram. Our result...

  18. Measurement of total alpha activity in water; Messung der Gesamt-Alpha-Aktivitaet in Wasser

    Energy Technology Data Exchange (ETDEWEB)

    Eikenberg, Jost [Paul Scherrer Institut (PSI), Villigen (Switzerland). Abt. fuer Strahlenschutz und Sicherheit; Florschuetz, Bernd [Hessisches Landesamt fuer Umwelt und Geologie, Kassel (Germany). Dezernat 15 - Strahlenschutz; Salvamoser, Josef [Institut fuer Angewandte Isotopen-, Gas- und Umweltuntersuchungen, Woerthsee (Germany); Steinkopff, Thomas [Deutscher Wetterdienst, Offenbach am Main (Germany); Wilhelm, Christoph [Karlsruher Institut fuer Technologie (KIT), Eggenstein-Leopoldshafen (Germany). Sicherheitsmanagement - Analytische Labore; Wisser, Sascha [FCI, Mainz (Germany)

    2014-04-01

    The article describes the measurement of the total alpha activity in an (evaporated) liquid sample, and the various sample preparation methods for measurements with proportional counters or LSC. (orig.)

  19. The active and passive kinematic difference between primary reverse and total shoulder prostheses

    NARCIS (Netherlands)

    Alta, T.D.; de Toledo, J.S.; Veeger, H.E.J.; Janssen, T.W.J.; Willems, W.J.

    2014-01-01

    Background: Reverse shoulder arthroplasty (RSA) and total shoulder arthroplasty (TSA) effectively decrease pain and improve clinical outcome. However, indications and biomechanical properties vary greatly. Our aim was to analyze both active and passive shoulder motion (thoracohumeral [TH],

  20. In vitro antioxidant, antibacterial and anti-tumor activities of total ...

    African Journals Online (AJOL)

    Purpose: To investigate the in vitro antioxidant, antibacterial and anti-tumor activities of total flavonoids from Elsholtzia densa Benth of Sichuan Province, China. Methods: The total flavonoids of Elsholtzia densa Bent were extracted utilizing the ultrasonic extraction method, and purified by D101 macroporous adsorption resin ...

  1. Quantitation of the degree of osteoporosis by measure of total-body calcium employing neutron activation

    International Nuclear Information System (INIS)

    Cohn, S.H.; Zanzi, I.; Vaswani, A.; Wallach, S.; Aloia, J.; Ellis, K.J.

    1975-01-01

    Two techniques for measuring the amount of Ca in the total skeleton were employed: total-body neutron activation analysis (TBNAA) and the determination of the mineral content of a bone of the appendicular skeleton (absorptiometric measurement of the radius, BMC). (U.S.)

  2. Assessment of total flavonoid content and antioxidant activity of Mullein (Verbascum songaricum ecotypes

    Directory of Open Access Journals (Sweden)

    2017-11-01

    Full Text Available Background and objectives: The Mullein genus is the largest genus of Scrophulariaceae family which has extensive natural habitat in southwest of Iran. Mullein contains compounds such as phenolic compounds, mucilage, saponins and anthocyanin. The aim of this study was to evaluate the total flavonoid content and antioxidant activity of mullein ecotypes in Iran. Methods: Six ecotypes of the Verbascum songaricum were evaluated. Determination of total flavonoid content was performed bythealuminium chloride colourimetric method. The antioxidant activity of the flower extracts was measured using the DPPH method. Results: The results showed that total flavonoid content and antioxidant activity were different among ecotypes.  The highest and lowest amounts of total flavonoidwas obtained  from Shermard ecotype (13.42 mg rutin /g DW and Klar ecotypes(10.10 mg rutin /g DW, respectively. The highest amounts of antioxidant activity were obtained from the Shermard ecotype (IC50 246.35 μg/mL. The correlation analysis showed that a significant relation between flavonoid, antioxidant activity and habitat elevation. Conclusion: Total flavonoid content and antioxidant activity of the samples were affected by habitat climatic.  The present data indicated that the highest antioxidant activity may be due to higher flavonoid content and the habitat elevation was effective on the flavonoid content. Due to the high amounts of flavonoid and antioxidant activity of mullein extract, it seems to be a good herbal option as an antioxidant in complementary therapies.

  3. The Role of Lightning in Controlling Interannual Variability of Tropical Tropospheric Ozone and OH and its Implications for Climate

    Science.gov (United States)

    Murray, Lee T.; Jacob, Daniel J.; Logan, Jennifer A.; Hudman, Rynda C.; Koshak, William J.

    2012-01-01

    Nitrogen oxides (NO(x) = NO + NO2) produced by lightning make a major contribution to the production of the dominant tropospheric oxidants (OH and ozone). These oxidants control the lifetime of many trace gases including long-lived greenhouse gases, and control the source-receptor relationship of inter-hemispheric pollutant transport. Lightning is affected by meteorological variability, and therefore represents a potentially important tropospheric chemistry-climate feedback. Understanding how interannual variability (IAV) in lightning affects IAV in ozone and OH in the recent past is important if we are to predict how oxidant levels may change in a future warmer climate. However, lightning parameterizations for chemical transport models (CTMs) show low skill in reproducing even climatological distributions of flash rates from the Lightning Imaging Sensor (LIS) and the Optical Transient Detector (OTD) satellite instruments. We present an optimized regional scaling algorithm for CTMs that enables sufficient sampling of spatiotemporally sparse satellite lightning data from LIS to constrain the spatial, seasonal, and interannual variability of tropical lightning. We construct a monthly time series of lightning flash rates for 1998-2010 and 35degS-35degN, and find a correlation of IAV in total tropical lightning with El Nino. We use the IAV-constraint to drive a 9-year hindcast (1998-2006) of the GEOS-Chem 3D chemical transport model, and find the increased IAV in LNO(x) drives increased IAV in ozone and OH, improving the model fs ability to simulate both. Although lightning contributes more than any other emission source to IAV in ozone, we find ozone more sensitive to meteorology, particularly convective transport. However, we find IAV in OH to be highly sensitive to lightning NO(x), and the constraint improves the ability of the model to capture the temporal behavior of OH anomalies inferred from observations of methyl chloroform and other gases. The sensitivity of

  4. Neurorehabilitation of cerebral disorders following lightning and electrical trauma.

    Science.gov (United States)

    Yarnell, Philip R

    2005-01-01

    The most devastating casualties in lightning and electrical trauma patients are the result of lesions of the nervous system, and especially lesions of the brain. The brain injuries can be divided into three categories: global dysfunction; focal brain injuries; and behavioral-cognitive sequelae without gross physical signs. Lightning injuries are usually the result of outdoor sports and leisure activities. Most electrical trauma cases are the result of workplace accidents. Rehabilitation planning should begin early after the incident and often needs to be continued for a long time. The goal of the rehabilitation team is to maximize functional return in patients with deficits related to brain lesions. The neurorehabilitation team includes the neurorehabilitation physician, physical therapists, occupational therapists, psychologists, speech therapists, and case managers.

  5. Geostationary Lightning Mapper: Lessons Learned from Post Launch Test

    Science.gov (United States)

    Edgington, S.; Tillier, C. E.; Demroff, H.; VanBezooijen, R.; Christian, H. J., Jr.; Bitzer, P. M.

    2017-12-01

    Pre-launch calibration and algorithm design for the GOES Geostationary Lightning Mapper resulted in a successful and trouble-free on-orbit activation and post-launch test sequence. Within minutes of opening the GLM aperture door on January 4th, 2017, lightning was detected across the entire field of view. During the six-month post-launch test period, numerous processing parameters on board the instrument and in the ground processing algorithms were fine-tuned. Demonstrated on-orbit performance exceeded pre-launch predictions. We provide an overview of the ground calibration sequence, on-orbit tuning of the instrument, tuning of the ground processing algorithms (event filtering and navigation). We also touch on new insights obtained from analysis of a large and growing archive of raw GLM data, containing 3e8 flash detections derived from over 1e10 full-disk images of the Earth.

  6. Effect of different cooking methods on total phenolic contents and antioxidant activities of four Boletus mushrooms.

    Science.gov (United States)

    Sun, Liping; Bai, Xue; Zhuang, Yongliang

    2014-11-01

    The influences of cooking methods (steaming, pressure-cooking, microwaving, frying and boiling) on total phenolic contents and antioxidant activities of fruit body of Boletus mushrooms (B. aereus, B. badius, B. pinophilus and B. edulis) have been evaluated. The results showed that microwaving was better in retention of total phenolics than other cooking methods, while boiling significantly decreased the contents of total phenolics in samples under study. Effects of different cooking methods on phenolic acids profiles of Boletus mushrooms showed varieties with both the species of mushroom and the cooking method. Effects of cooking treatments on antioxidant activities of Boletus mushrooms were evaluated by in vitro assays of hydroxyl radical (OH·) -scavenging activity, reducing power and 1, 1-diphenyl-2-picrylhydrazyl radicals (DPPH·) -scavenging activity. Results indicated the changes of antioxidant activities of four Boletus mushrooms were different in five cooking methods. This study could provide some information to encourage food industry to recommend particular cooking methods.

  7. Total. Group dynamics and activities. Competitive environment and strategic perspectives. Release - July 2017

    International Nuclear Information System (INIS)

    2017-07-01

    After a synthesis which notably proposes a SWOT analysis of the Total group, this report proposes a presentation of the Total Group (general overview, presentation of activities, human resources, shareholder structure and stock market data, competitive environment). It gives an overview of the Total group dynamics and of its activities through a presentation of an environment analysis (world oil demand, refining-chemistry activity, hydrocarbon prices), a presentation of the group activity (turnover, turnover per segment, operational income and financial results of competitors). It comments important events and development axes: four strategic orientations, strengthening of the upstream pole, restructuring of refining and chemical activities, widening of the energy provision, consolidation of positions in the marketing and services sector. Financial data are presented along with the main economic and financial indicators. Important statistical data are provided

  8. A simple lightning assimilation technique for improving ...

    Science.gov (United States)

    Convective rainfall is often a large source of error in retrospective modeling applications. In particular, positive rainfall biases commonly exist during summer months due to overactive convective parameterizations. In this study, lightning assimilation was applied in the Kain-Fritsch (KF) convective scheme to improve retrospective simulations using the Weather Research and Forecasting (WRF) model. The assimilation method has a straightforward approach: force KF deep convection where lightning is observed and, optionally, suppress deep convection where lightning is absent. WRF simulations were made with and without lightning assimilation over the continental United States for July 2012, July 2013, and January 2013. The simulations were evaluated against NCEP stage-IV precipitation data and MADIS near-surface meteorological observations. In general, the use of lightning assimilation considerably improves the simulation of summertime rainfall. For example, the July 2012 monthly averaged bias of 6 h accumulated rainfall is reduced from 0.54 to 0.07 mm and the spatial correlation is increased from 0.21 to 0.43 when lightning assimilation is used. Statistical measures of near-surface meteorological variables also are improved. Consistent improvements also are seen for the July 2013 case. These results suggest that this lightning assimilation technique has the potential to substantially improve simulation of warm-season rainfall in retrospective WRF applications. The

  9. Characteristics of cloud-to-ground lightning flashes over Sweden

    International Nuclear Information System (INIS)

    Sonnadara, Upul; Cooray, Vernon; Goetschl, Thomas

    2006-01-01

    A detailed study of the characteristics of cloud-to-ground (CG) lightning flashes over Sweden was carried out for the period 1987-2000 using data obtained from the Swedish lightning-locating network. Results are presented by analysing over half a million lightning ground flashes. The average variation of the annual mean of the total number of flashes was found to be 37%. About 12% of the CG flashes were positive flashes and their average variation about the annual mean was 26%. The average peak currents were fairly constant over the years with variations as little as 4% for negative flashes and 5% for positive flashes. The average peak current values for negative and positive flashes were -29.90 and +63.97 kA respectively. A correlation between the mean monthly flash count and percentage of positive flashes was seen. A similar relationship is seen with the mean monthly flash count and the peak currents for both polarities. In general, high flash density and high peak currents were observed in the southern part of Sweden where most of the major cities are located. Flash densities exceeding 0.4 flashes km -2 were observed for several large cities. The maximum flash rate of 32 flashes h -1 within a 10 km radius was seen in Joenkoeping (14.18 0 E, 57.78 0 N) in the province of Smaaland

  10. Total sitting time, leisure time physical activity and risk of hospitalization due to low back pain

    DEFF Research Database (Denmark)

    Balling, Mie; Holmberg, Teresa; Petersen, Christina B

    2018-01-01

    AIMS: This study aimed to test the hypotheses that a high total sitting time and vigorous physical activity in leisure time increase the risk of low back pain and herniated lumbar disc disease. METHODS: A total of 76,438 adults answered questions regarding their total sitting time and physical...... activity during leisure time in the Danish Health Examination Survey 2007-2008. Information on low back pain diagnoses up to 10 September 2015 was obtained from The National Patient Register. The mean follow-up time was 7.4 years. Data were analysed using Cox regression analysis with adjustment...

  11. Lightning mapper and the future

    Science.gov (United States)

    Christian, H. J.

    1985-01-01

    A trade-off analysis was completed that reveals how the lightning mapper detection efficiency will change as a function of interference filter bandwidth, pixel field of view, and telescope aperture. It is shown that the critical parameter on which we have minimum flexibility is filter band-width. The problem is that too narrow a filter bandwidth is incompatible with wide areal coverage. The trade-off analysis demonstrates that an 80 percent lightning detection efficiency will technically be relatively straight-forward, while a 90 percent detection efficiency will apparently be difficult to achieve. Three focal plane designs are currently under consideration. One would use a single large, solid state silicon integrating array with multiple output channels and off-the-focal-plane analog, time domain, background removing fibers. A second design would use the same technology, but the sensor would consist of up to four virtually independent focal plane arrays. This design reduces the areal coverage of each detector. Thus narrower interference filters could be utilized. Superior performance would be realized at a probable increase in cost. The final design would use a three-dimensional focal plane in order to perform background removal at the focal plane. Superior performance would be achieved along with reduced weight and power requirements. Unfortunately, this focal plane technology is still under development.

  12. Ultrasound-Assisted Extraction of Total Flavonoids from Corn Silk and Their Antioxidant Activity

    Directory of Open Access Journals (Sweden)

    Ling-Li Zheng

    2016-01-01

    Full Text Available Object. Ultrasound-assisted extraction of total flavonoids from corn silk and their antioxidant activities were studied. Methods. Response surface methodology was adopted to optimize the extraction conditions and antioxidant activities of the extracted total flavonoids were detected through ferric reducing antioxidant power (FRAP assay. Results. Through a three-level, three-variable Box-Behnken design of response surface methodology (RSM adopting yield as response, the optimal conditions were determined as follows: ultrasonic power 500 W, extraction time 20 min, material solvent ratio 1 : 20, and ethanol concentration 30%. Under the optimum conditions, the extraction yield of total flavonoids was 1.13%. FRAP value of total flavonoids extracted from corn silk was 467.59 μmol/L. Conclusion. The total flavonoids of corn silk could be developed as food natural antioxidant reagents.

  13. Monitoring the development of volcanic eruptions through volcanic lightning - Using a lightning mapping array, seismic and infrasound array, and visual plume analysis

    Science.gov (United States)

    Smith, C. M.; Thompson, G.; McNutt, S. R.; Behnke, S. A.; Edens, H. E.; Van Eaton, A. R.; Gaudin, D.; Thomas, R. J.

    2017-12-01

    The period of 28 May - 7 June 2015 at Sakurajima Volcano, Japan witnessed a multitude of Vulcanian eruptive events, which resulted in plumes reaching 500-3000m above the vent. These plumes varied from white, gas-rich plumes to dark grey and black ash-rich plumes, and were recorded on lowlight and infrared cameras. A nine-station lightning mapping array (LMA) was deployed to locate sources of VHF (67-73 MHz) radiation produced by lightning flashes and other types of electrical activity such as `continuous RF (radio frequency)'. Two Nanometrics Trillium broadband seismometers and six BSU infrasound sensors were deployed. Over this ten day period we recorded 1556 events that consisted of both seismic and infrasound signals, indicating explosive activity. There are an additional 1222 events that were recorded as only seismic or infrasound signals, which may be a result of precursory seismic signals or noise contamination. Plume discharge types included both distinct lightning flashes and `continuous RF'. The LMA ran continuously for the duration of the experiment. On 30 May 2015 at least seven lightning flashes were also detected by the Vaisala Global Lightning Detection 360 network, which detects VLF (3-30 kHz) radiation. However the University of Washington's World Wide Lightning Location Network, which also detects VLF radiation, detected no volcanic lightning flashes in this time period. This indicates that the electrical activity in Sakurajima's plume occurs near the lower limits of the VLF detection threshold. We investigate relationships between the plume dynamics, the geophysical signal and the corresponding electrical activity through: plume velocity and height; event waveform cross-correlation; volcano acoustic-seismic ratios; overall geophysical energy; RSAM records; and VHF sources detected by the LMA. By investigating these relationships we hope to determine the seismic/infrasound energy threshold required to generate measurable electrical activity

  14. Design quality control of the activity determination total alpha liquid effluents; Diseno de control de calidad de la determinacion de actividad alfa total en efluentes liquidos

    Energy Technology Data Exchange (ETDEWEB)

    Yague, L.; Alvarez, A.; Navarro, N.; Noguerales, C.

    2011-07-01

    The total alpha activity index is the joint action of all alpha emissions in a sample. This is a very useful in designing the analytical control of liquid effluent into the environment. Presents the design of quality control applied to the determination of total alpha activity.

  15. ANTIOXIDANT ACTIVITY, TOTAL PHENOLIC AND FLAVONOID CONTENT OF MORINDA CITRIFOLIA FRUIT EXTRACTS FROM VARIOUS EXTRACTION PROCESSES

    Directory of Open Access Journals (Sweden)

    PRAVEEN K. RAMAMOORTHY

    2007-04-01

    Full Text Available Soxhlet, Ultrasonic extract of Morinda citrifolia L. fruit and four extracts from high pressure extraction at 10 MPa using ethanol, ethyl acetate as solvent and dried by vacuum oven and spray dryer were analyzed for their antioxidant activity by peroxide value method and diphenylpicrylhydrazyl radical scavenging method. The five extracts along with the reference samples, butylated hydroxyl toluene and tannic acid were further analyzed to determine their total phenolic content by Folin-Ciocalteau method and total flavonoid content by Dowd method. The M. citrifolia extract by high pressure extraction with ethyl acetate as solvent and spray dried was found to exhibit highest antioxidant activity and total flavonoid content. High total phenolic content was determined in the high pressure extract using ethyl acetate as solvent and vacuum dried. It was interesting to note that ultrasonic extract exhibited significant antioxidant activity, total phenolic and flavonoid content. High pressure extracted M. citrifolia in ethanol was found to express lesser values comparatively. The significant difference in activity among the high pressure extracts was found to be due to the polarity of the solvents used for extraction as M. citrifolia fruit contains relatively larger quantity of non-polar antioxidant compounds. It was also found that the drying methods had significant impact on the antioxidant activity, total phenolic and flavonoid content of the extracts.

  16. Lightning strike-induced brachial plexopathy

    Directory of Open Access Journals (Sweden)

    Amita N Bhargava

    2014-01-01

    Full Text Available We describe a patient who presented with a history of lightning strike injury. Following the injury, he sustained acute right upper limb weakness with pain. Clinically, the lesion was located to the upper and middle trunk of the right brachial plexus, and the same confirmed with electrophysiological studies. Nerve damage due to lightning injuries is considered very rare, and a plexus damage has been described infrequently, if ever. Thus, the proposed hypothesis that lightning rarely causes neuropathy, as against high-voltage electric current, due to its shorter duration of exposure not causing severe burns which lead to nerve damage, needs to be reconsidered.

  17. Lightning on jupiter: rate, energetics, and effects.

    Science.gov (United States)

    Lewis, J S

    1980-12-19

    Voyager data on the optical and radio-frequency detection of lightning discharges in the atmosphere of Jupiter suggest a stroke rate significantly lower than on the earth. The efficiency of conversion of atmospheric convective energy flux into lightning is almost certainly less than on the earth, probably near 10(-7) rather than the terrestrial value of 10(-4). At this level the rate of production of complex organic molecules by lightning and by thunder shock waves is negligible compared to the rates of known photochemical processes for forming colored inorganic solids.

  18. Lightning on Jupiter - Rate, energetics, and effects

    Science.gov (United States)

    Lewis, J. S.

    1980-01-01

    Voyager data on the optical and radio-frequency detection of lightning discharges in the atmosphere of Jupiter suggest a stroke rate significantly lower than on the earth. The efficiency of conversion of atmospheric convective energy flux into lightning is almost certainly less than on the earth, probably near 10 to the -7th rather than the terrestrial value of 10 to the -4th. At this level the rate of production of complex organic molecules by lightning and by thunder shock waves is negligible compared to the rates of known photochemical processes for forming colored inorganic solids.

  19. Physical Activity Participation Among Patients After Total Hip and Knee Arthroplasty

    NARCIS (Netherlands)

    Stevens, Martin; Reininga, Inge H. F.; Bulstra, Sjoerd K.; Wagenmakers, Robert; van den Akker-Scheek, Inge

    Total hip (THA) and knee arthroplasty (TKA) are successful operative interventions, yet little is known about the physical activity behavior of patients after THA/TKA. For older adults, there are beneficial effects of regular physical activity after THA/TKA. The objective of this paper is to review

  20. Overview of total beta activity index and beta rest in surface waters of the Spanish rivers

    International Nuclear Information System (INIS)

    Pujol, L.; Payeras, J.; Pablo, M. A. de

    2013-01-01

    This work aims to give an overview of the index of total beta activity and the activity index beta rest in surface waters of the main Spanish rivers. These indices are a parameter over water quality that CEDEX comes determined by order of the Ministry of Agriculture, Food and Environment, in water policy. (Author)

  1. Giant elves: Lightning-generated electromagnetic pulses in giant planets.

    Science.gov (United States)

    Luque Estepa, Alejandro; Dubrovin, Daria; José Gordillo-Vázquez, Francisco; Ebert, Ute; Parra-Rojas, Francisco Carlos; Yair, Yoav; Price, Colin

    2015-04-01

    We currently have direct optical observations of atmospheric electricity in the two giant gaseous planets of our Solar System [1-5] as well as radio signatures that are possibly generated by lightning from the two icy planets Uranus and Neptune [6,7]. On Earth, the electrical activity of the troposphere is associated with secondary electrical phenomena called Transient Luminous Events (TLEs) that occur in the mesosphere and lower ionosphere. This led some researchers to ask if similar processes may also exist in other planets, focusing first on the quasi-static coupling mechanism [8], which on Earth is responsible for halos and sprites and then including also the induction field, which is negligible in our planet but dominant in Saturn [9]. However, one can show that, according to the best available estimation for lightning parameters, in giant planets such as Saturn and Jupiter the effect of the electromagnetic pulse (EMP) dominates the effect that a lightning discharge has on the lower ionosphere above it. Using a Finite-Differences, Time-Domain (FDTD) solver for the EMP we found [10] that electrically active storms may create a localized but long-lasting layer of enhanced ionization of up to 103 cm-3 free electrons below the ionosphere, thus extending the ionosphere downward. We also estimate that the electromagnetic pulse transports 107 J to 1010 J toward the ionosphere. There emissions of light of up to 108 J would create a transient luminous event analogous to a terrestrial elve. Although these emissions are about 10 times fainter than the emissions coming from the lightning itself, it may be possible to target them for detection by filtering the appropiate wavelengths. [1] Cook, A. F., II, T. C. Duxbury, and G. E. Hunt (1979), First results on Jovian lightning, Nature, 280, 794, doi:10.1038/280794a0. [2] Little, B., C. D. Anger, A. P. Ingersoll, A. R. Vasavada, D. A. Senske, H. H. Breneman, W. J. Borucki, and The Galileo SSI Team (1999), Galileo images of

  2. ENSO Related Inter-Annual Lightning Variability from the Full TRMM LIS Lightning Climatology

    Science.gov (United States)

    Clark, Austin; Cecil, Daniel

    2018-01-01

    The El Nino/Southern Oscillation (ENSO) contributes to inter-annual variability of lightning production more than any other atmospheric oscillation. This study further investigated how ENSO phase affects lightning production in the tropics and subtropics using the Tropical Rainfall Measuring Mission (TRMM) Lightning Imaging Sensor (LIS). Lightning data were averaged into mean annual warm, cold, and neutral 'years' for analysis of the different phases and compared to model reanalysis data. An examination of the regional sensitivities and preliminary analysis of three locations was conducted using model reanalysis data to determine the leading convective mechanisms in these areas and how they might respond to the ENSO phases

  3. Activities Contributing to Total Energy Expenditure in the United States: Results from the NHAPS Study

    Directory of Open Access Journals (Sweden)

    Block Gladys

    2004-02-01

    Full Text Available Abstract Background Physical activity is increasingly recognized as an important factor influencing health and disease status. Total energy expenditure, both low-intensity and high-intensity, contributes to maintenance of healthy body weight. This paper presents the results of a quantitative approach to determining the activities that contribute to total energy expenditure in the United States. Methods Data from the National Human Activity Pattern Survey (NHAPS were used. In 1992–1994 the NHAPS sampled 4,185 females and 3,330 males, aged 18 years and over, weighted to be representative of the 48 contiguous United States. A detailed report of each activity performed in the previous 24 hours was obtained. A score was created for each activity, by multiplying duration and intensity for each individual and summing across individuals. This score was then used to rank each activity according to its contribution to total population energy expenditure, for the total sample and separately for each gender, race, age, region, and season. Results This analysis reveals our society to be primarily sedentary; leisure time physical activity contributed only approximately 5% of the population's total energy expenditure. Not counting sleeping, the largest contributor to energy expenditure was "Driving a car", followed by "Office work" and "Watching TV". Household activities accounted for 20.1% and 33.3% of energy expenditure for males and females respectively. Conclusion The information presented in this paper may be useful in identifying common activities that could be appropriate targets for behavioral interventions to increase physical activity.

  4. Automated sensing of thunderstorm characteristics and lightning parameters in the south of the European part of the Russian Federation

    Science.gov (United States)

    Adzhiev, Anatoly Kh.; Boldyreff, Anton S.; Kuliev, Dalkhat D.; Borisov, Igor V.; Korogodova, Irina V.

    2017-10-01

    In the present study the results of instrument measurements of thunderstorm activity and lightning parameters on the territory of the south of the European part of the Russian Federation is received. The automated hardware-software complex for thunderstorm activity sensing is developed. It consists of lightning sensors, electric field mills, meteorological radiolocator (MRL-5) for sensing the radar characteristics of clouds, meteorological stations and software for data collection, analysis and processing. Features of spatial-temporal variations of the thunderstorm activity and lightning parameters on the territory of 650 km around the measurement center of High-Mountain Geophysical Institute (Nalchik) were found. The relations between the quantities of intracloud, cloud-to-cloud and cloud-to-ground (positive and negative) discharges were studied. Parameters of current of the lightning discharges of different polarities under the flat and mountainous terrain were received and analyzed in the paper.

  5. Investigating the Differences in the Total and Active Microbial Community of Mid-Atlantic Ridge Sediments

    Science.gov (United States)

    Sobol, M. S.; Zinke, L. A.; Orcutt, B.; Mills, H. J.; Edwards, K. J.; Girguis, P. R.; Reese, B. K.

    2016-02-01

    Microbes in the marine deep subsurface are key mediators of many geochemical cycles. It is important to understand how microbial communities and the diversity of those communities impacts geochemical cycling. Sediment cores were collected from IODP (Integrated Ocean Drilling Program) Expedition 336 to the western flank of the mid-Atlantic ridge also referred to as North Pond. The dissolved oxygen concentration decreased with depth for 60-70 mbsf, followed by a sharp increase in oxygen until it terminated at the basement. The 16S rRNA genes (DNA) and transcripts (RNA) were extracted simultaneously using a method designed by Reese et al. (2013) to differentiate between the total and active microbial community structures, respectively, as well as correlate the putative metabolism with the geochemistry. We observed many differences between the active and total communities. Sequences most closely related to Cyanobacteria were found to dominate the total community at both sites, but were found in small numbers in the active community. The most abundant phyla in the active community were Alphaproteobacteria, which suggests that they may have high activity even though the abundance was not as great in the total community. This suggests that, even in small numbers, bacteria are capable of contributing greatly to their environment. Principal Component Analysis (PCA) and Singular Value Decomposition (SVD) showed that iron-reducing bacteria in the active (RNA) community correlated strongly with solid phase iron oxides. SVD also showed that the putative nitrate reducers in the active community were found in greater abundance where porewater NO3- and NO2- total concentrations were elevated. Overall, the active (RNA) community correlated significantly with the geochemistry whereas the total (DNA) community did not. Therefore, RNA analysis yields a more accurate representation of how microbial communities impact geochemical cycling.

  6. [Experimental evidence of against cough activity of total alkaloids from Guiera senegalensis Lam. in guinea pig;].

    Science.gov (United States)

    Diatta, W; Fall, A D; Dièye, A M; Faty, S; Bassène, E; Faye, B

    2007-01-01

    Against cough activity from Guiera senegalensis' leaves has been previously scientifically studied. However, to the best of our knowledge, active principles responsible of this activity were not yet identified. Thus, we undertook this work with the aim to evaluate the effect of total alkaloids from plant's leaves in cough induced in guinea pig by ammoniac inhalation. Guinea pigs were divided up in 5 groups of 10 and were crammed with distilled water (control), total alkaloids with 10, 25 and 30 mg/kg and codeine with 50 mg/kg. They were then exposed to ammoniac inhalations and the number of coughs was counted every hour, after cramming, during 5 min. Our results show, after 5 hours, with the doses of 15, 25 and 30 mg/kg per os, that total alkaloids induce against cough activity, 2 hours after cramming (p < 0.01) and the difference was still significant 3, 4 and 5 hours after (p < 0.001). These alkaloids effects were comparable with codeine activity which was used as reference product. Total alkaloids of Guiera senegalensis present an against cough activity and would be responsible of against cough activity of the plant.

  7. Combined Aircraft and Satellite-Derived Storm Electric Current and Lightning Rates Measurements and Implications for the Global Electric Circuit

    Science.gov (United States)

    Mach, Douglas M.; Blakeslee, Richard J.; Bateman, Monte G.

    2010-01-01

    Using rotating vane electric field mills and Gerdien capacitors, we measured the electric field profile and conductivity during 850 overflights of electrified shower clouds and thunderstorms spanning regions including the Southeastern United States, the Western Atlantic Ocean, the Gulf of Mexico, Central America and adjacent oceans, Central Brazil, and the South Pacific. The overflights include storms over land and ocean, with and without lightning, and with positive and negative fields above the storms. The measurements were made with the NASA ER-2 and the Altus-II high altitude aircrafts. Peak electric fields, with lightning transients removed, ranged from -1.0 kV/m to 16 kV/m, with a mean value of 0.9 kV/m. The median peak field was 0.29 kV/m. Integrating our electric field and conductivity data, we determined total conduction currents and flash rates for each overpass. With knowledge of the storm location (land or ocean) and type (with or without lightning), we determine the mean currents by location and type. The mean current for ocean storms with lightning is 1.6 A while the mean current for land storms with lightning is 1.0 A. The mean current for oceanic storms without lightning (i.e., electrified shower clouds) is 0.39 A and the mean current for land storms without lightning is 0.13 A. Thus, on average, land storms with or without lightning have about half the mean current as their corresponding oceanic storm counterparts. Over three-quarters (78%) of the land storms had detectable lightning, while less than half (43%) of the oceanic storms had lightning. We did not find any significant regional or latitudinal based patterns in our total conduction currents. By combining the aircraft derived storm currents and flash rates with diurnal lightning statistics derived from the Lightning Imaging Sensor (LIS) and Optical Transient Detector (OTD) low Earth orbiting satellites, we reproduce the diurnal variation in the global electric circuit (i.e., the Carnegie

  8. Evolution of lightning in an isolated hailstorm of moderate size in the tropics

    Science.gov (United States)

    Kamra, A. K.; Pawar, S. D.

    2007-10-01

    Evolution of lightning activity in a tropical hailstorm of moderate size that developed in the premonsoon season at Pune (18°32'N, 73°51'E, 559 m above sea level) is studied from the measurements of surface electric field, the Maxwell current and thunder. Total flash rate is counted from the electric field record, and the cloud-to-ground (CG) flash rate is estimated from the visual observations. Precise timings of their occurrence were confirmed from the observations of overshoot in the Maxwell current records. The storm exhibited an almost constant rate of one CG flash every 1 to 2 min over the whole life time of the storm. The ratio of intracloud (IC) to CG flashes (IC/CG) increased with the increase in total flash rate. In the convective stage of the storm, field changes from consecutive flashes were generally found to alternate in polarity. Moreover, in this stage, field changes occur in pairs, the first field change of each pair being of negative polarity and the second one of positive polarity. The two field changes in a pair occur with an average time difference of 14.3 ± 8.4 s while two consecutive pairs appear after 29.3 ± 9.1 s. In between the convective and mature stages, our observations suggest the occurrence of the phenomenon of rain gush and the field excursion associated with falling precipitation. Development of the mature stage was marked with rapid transitions in the surface electric field and the Maxwell current polarities from negative to positive. Further, total flash rate and IC/CG ratio sharply increase, and the lightning-induced electric field changes become almost exclusively of negative polarity. Observations suggest possibly a lifting up of the charging region in mature stage of the storm. The dissipating stage of the storm witnessed hail and rain showers, sharp transition of electric field and the Maxwell current from positive to negative polarity and occurrence of a few positive CG discharges. Our observations are consistent with

  9. Acoustic Network Localization and Interpretation of Infrasonic Pulses from Lightning

    Science.gov (United States)

    Arechiga, R. O.; Johnson, J. B.; Badillo, E.; Michnovicz, J. C.; Thomas, R. J.; Edens, H. E.; Rison, W.

    2011-12-01

    We improve on the localization accuracy of thunder sources and identify infrasonic pulses that are correlated across a network of acoustic arrays. We attribute these pulses to electrostatic charge relaxation (collapse of the electric field) and attempt to model their spatial extent and acoustic source strength. Toward this objective we have developed a single audio range (20-15,000 Hz) acoustic array and a 4-station network of broadband (0.01-500 Hz) microphone arrays with aperture of ~45 m. The network has an aperture of 1700 m and was installed during the summers of 2009-2011 in the Magdalena mountains of New Mexico, an area that is subject to frequent lightning activity. We are exploring a new technique based on inverse theory that integrates information from the audio range and the network of broadband acoustic arrays to locate thunder sources more accurately than can be achieved with a single array. We evaluate the performance of the technique by comparing the location of thunder sources with RF sources located by the lightning mapping array (LMA) of Langmuir Laboratory at New Mexico Tech. We will show results of this technique for lightning flashes that occurred in the vicinity of our network of acoustic arrays and over the LMA. We will use acoustic network detection of infrasonic pulses together with LMA data and electric field measurements to estimate the spatial distribution of the charge (within the cloud) that is used to produce a lightning flash, and will try to quantify volumetric charges (charge magnitude) within clouds.

  10. Weekend-weekday lightning variability for an urban region

    Science.gov (United States)

    Bentley, M. L.; Stallins, J. A.; Ashley, W. S.

    2011-12-01

    We characterized differences in warm-season weekday and weekend aerosol conditions and cloud-to- ground (CG) flashes (1995-2008) for an 80,000 square kilometer region around Atlanta, Georgia. Under weekday aerosol concentrations, a greater augmentation of CG flash activity within a 100 km radius around Atlanta was found. On weekends these effects contracted toward the city. This minimized any weekly anthropogenic cycle over the more densely populated urban center even though this location had a higher flash density, a higher percentage of days with flashes, and stronger peak currents over the course of a week compared to the surrounding region. The sharper contrasts in weekday and weekend lightning regime developed outside the perimeter of the city over non urban land uses. Here lightning on weekend and weekdays differed more in its density, frequency, polarity, and peak current. Across the full extent of the study region, weekday peak currents were stronger and flash days more frequent, suggesting that weekly CG lightning signals have a regional component not tied to a single city source.

  11. Adult total wellness: group differences based on sitting time and physical activity level.

    Science.gov (United States)

    Barwais, Faisal A; Cuddihy, Thomas F; Tomson, L Michaud

    2014-03-06

    An increasing body of evidence associates a high level of sitting time with poor health outcomes. The benefits of moderate to vigorous-intensity physical activities to various aspects of health are now well documented; however, individuals may engage in moderate-intensity physical activity for at least 30 minutes on five or more days of the week and still exhibit a high level of sitting time. This purpose of this study was to examine differences in total wellness among adults relative to high/low levels of sitting time combined with insufficient/sufficient physical activity (PA). The construct of total wellness incorporates a holistic approach to the body, mind and spirit components of life, an approach which may be more encompassing than some definitions of health. Data were obtained from 226 adult respondents (27±6 years), including 116 (51%) males and 110 (49%) females. Total PA and total sitting time were assessed with the International Physical Activity Questionnaire (IPAQ) (short-version). The Wellness Evaluation of Lifestyle Inventory was used to assess total wellness. An analysis of covariance (ANCOVA) was utilised to assess the effects of the sitting time/physical activity group on total wellness. A covariate was included to partial out the effects of age, sex and work status (student or employed). Cross-tabulations were used to show associations between the IPAQ derived high/low levels of sitting time with insufficient/sufficient PA and the three total wellness groups (i.e. high level of wellness, moderate wellness and wellness development needed). The majority of the participants were located in the high total sitting time and sufficient PA group. There were statistical differences among the IPAQ groups for total wellness [F (2,220)=32.5 (pwellness [χ2 (N=226)=54.5, pwellness development needed group. In contrast, 72% of participants who were located in the low total sitting time/sufficient PA group were situated in the moderate wellness group. Many

  12. Adaptive active control of structural vibration by minimisation of total supplied power

    DEFF Research Database (Denmark)

    Henriksen, Eigil

    1996-01-01

    Active control of vibration by minimisation of total supplied power is an attractive approach from a theoretical point of view. In this practical study of the method two secondary sources were applied to control the sinusoidal excitation of an aluminium beam from a single primary source. The cont......Active control of vibration by minimisation of total supplied power is an attractive approach from a theoretical point of view. In this practical study of the method two secondary sources were applied to control the sinusoidal excitation of an aluminium beam from a single primary source....... The control algorithm was able to reduce the total supplied source power in a frequency band ranging from 50 to 500 Hz. The algorithm is surprisingly insensitive to measurement errors. However, very precise estimates of the power from the individual sources are required to quantify the total supplied power....

  13. Energy transfer problems of ball lightning

    Energy Technology Data Exchange (ETDEWEB)

    Egely, G.

    1986-04-01

    The paper analyzes the energy transport phenomenon of ball lightnings, but momentum and charge transport phenomena are considered as well. The physical properties as energy density and transfer are investigated using several observers' accounts of interactions with different objects. It is shown that contrary to previous assumptions the ball lightning has negative electric charge, and very high internal energy density. Both internal and external energy source models are analyzed, and it is shown that regardless to the details of a given model neither of them can explain actual observations. This has been validated by a well documented case study, and by several additional observations. An entirely new, testable model is suggested, which is able to stand for all observed properties of ball lightnings, and it explains the cause of rarity of ball lightnings, and the reasons of the unsuccessful experimental efforts. It is shown that the plasma sphere is just a visible side effect of a more important phenomenon.

  14. A solid state lightning propagation speed sensor

    Science.gov (United States)

    Mach, Douglas M.; Rust, W. David

    1989-01-01

    A device to measure the propagation speeds of cloud-to-ground lightning has been developed. The lightning propagation speed (LPS) device consists of eight solid state silicon photodetectors mounted behind precision horizontal slits in the focal plane of a 50-mm lens on a 35-mm camera. Although the LPS device produces results similar to those obtained from a streaking camera, the LPS device has the advantages of smaller size, lower cost, mobile use, and easier data collection and analysis. The maximum accuracy for the LPS is 0.2 microsec, compared with about 0.8 microsecs for the streaking camera. It is found that the return stroke propagation speed for triggered lightning is different than that for natural lightning if measurements are taken over channel segments less than 500 m. It is suggested that there are no significant differences between the propagation speeds of positive and negative flashes. Also, differences between natural and triggered dart leaders are discussed.

  15. GRIP LIGHTNING INSTRUMENT PACKAGE (LIP) V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The Lightning Instrument Package (LIP) consists of 6 rotating vane type electric field sensors along with a central computer to record and monitor the instruments....

  16. Central hyperadrenergic state after lightning strike.

    Science.gov (United States)

    Parsaik, Ajay K; Ahlskog, J Eric; Singer, Wolfgang; Gelfman, Russell; Sheldon, Seth H; Seime, Richard J; Craft, Jennifer M; Staab, Jeffrey P; Kantor, Birgit; Low, Phillip A

    2013-08-01

    To describe and review autonomic complications of lightning strike. Case report and laboratory data including autonomic function tests in a subject who was struck by lightning. A 24-year-old man was struck by lightning. Following that, he developed dysautonomia, with persistent inappropriate sinus tachycardia and autonomic storms, as well as posttraumatic stress disorder (PTSD) and functional neurologic problems. The combination of persistent sinus tachycardia and episodic exacerbations associated with hypertension, diaphoresis, and agitation was highly suggestive of a central hyperadrenergic state with superimposed autonomic storms. Whether the additional PTSD and functional neurologic deficits were due to a direct effect of the lightning strike on the central nervous system or a secondary response is open to speculation.

  17. RAPID KNEE-EXTENSIONS TO INCREASE QUADRICEPS MUSCLE ACTIVITY IN PATIENTS WITH TOTAL KNEE ARTHROPLASTY

    DEFF Research Database (Denmark)

    Husted, Rasmus Skov; Wilquin, Lousia; Jakobsen, Thomas Linding

    2017-01-01

    BACKGROUND: Inhibition of the quadriceps muscle and reduced knee-extension strength is common shortly following total knee arthroplasty (weeks to months), due to reduced voluntary activation of the quadriceps muscle. In healthy subjects, strength training with heavy loads is known to increase...... agonist muscle activity, especially if the exercise is conducted using rapid muscle contractions. PURPOSE: The purpose of this study was to examine if patients with total knee arthroplasty could perform rapid knee-extensions using a 10 RM load four to eight weeks after surgery, and the degree to which...... rapid knee-extensions were associated with greater voluntary quadriceps muscle activity during an experimental strength training session, compared to that elicited using slow knee-extensions. STUDY DESIGN: A randomized cross-over study. METHODS: Twenty-four patients (age 66.5) 4-8 weeks post total knee...

  18. RAPID KNEE-EXTENSIONS TO INCREASE QUADRICEPS MUSCLE ACTIVITY IN PATIENTS WITH TOTAL KNEE ARTHROPLASTY

    DEFF Research Database (Denmark)

    Husted, Rasmus Skov; Wilquin, Lousia; Jakobsen, Thomas Linding

    2017-01-01

    agonist muscle activity, especially if the exercise is conducted using rapid muscle contractions. PURPOSE: The purpose of this study was to examine if patients with total knee arthroplasty could perform rapid knee-extensions using a 10 RM load four to eight weeks after surgery, and the degree to which......BACKGROUND: Inhibition of the quadriceps muscle and reduced knee-extension strength is common shortly following total knee arthroplasty (weeks to months), due to reduced voluntary activation of the quadriceps muscle. In healthy subjects, strength training with heavy loads is known to increase...... rapid knee-extensions were associated with greater voluntary quadriceps muscle activity during an experimental strength training session, compared to that elicited using slow knee-extensions. STUDY DESIGN: A randomized cross-over study. METHODS: Twenty-four patients (age 66.5) 4-8 weeks post total knee...

  19. Rapid knee-extensions to increase quadriceps muscle activity in patients with total knee arthroplasty

    DEFF Research Database (Denmark)

    Husted, Rasmus Skov; Wilquin, Lousia; Jakobsen, Thomas Linding

    2017-01-01

    agonist muscle activity, especially if the exercise is conducted using rapid muscle contractions. PURPOSE: The purpose of this study was to examine if patients with total knee arthroplasty could perform rapid knee-extensions using a 10 RM load four to eight weeks after surgery, and the degree to which......BACKGROUND: Inhibition of the quadriceps muscle and reduced knee-extension strength is common shortly following total knee arthroplasty (weeks to months), due to reduced voluntary activation of the quadriceps muscle. In healthy subjects, strength training with heavy loads is known to increase...... rapid knee-extensions were associated with greater voluntary quadriceps muscle activity during an experimental strength training session, compared to that elicited using slow knee-extensions. STUDY DESIGN: A randomized cross-over study. METHODS: Twenty-four patients (age 66.5) 4-8 weeks post total knee...

  20. Lightning protection system for a wind turbine

    Science.gov (United States)

    Costin, Daniel P [Chelsea, VT; Petter, Jeffrey K [Williston, VT

    2008-05-27

    In a wind turbine (104, 500, 704) having a plurality of blades (132, 404, 516, 744) and a blade rotor hub (120, 712), a lightning protection system (100, 504, 700) for conducting lightning strikes to any one of the blades and the region surrounding the blade hub along a path around the blade hub and critical components of the wind turbine, such as the generator (112, 716), gearbox (708) and main turbine bearings (176, 724).

  1. Increased Walking's Additive and No Substitution Effect on Total Physical Activity.

    Science.gov (United States)

    Kang, Bumjoon; Moudon, Anne V; Hurvitz, Philip M; Saelens, Brian E

    2018-03-01

    We assessed the associations between a change in time spent walking and a change in total physical activity (PA) time within an urban living adult sample to test for additive or substitution effects. Participants living in the greater Seattle area were assessed in 2008-2009 and again 1-2 yr later (2010-2011). At each time point, they wore accelerometers and GPS units and recorded trips and locations in a travel diary for seven consecutive days. These data streams were combined to derive a more objective estimate of walking and total PA. Participants also completed the International Physical Activity Questionnaire to provide self-reported estimates of walking and total PA. Regression analyses assessed the associations between within-participant changes in objective and self-reported walking and total PA. Data came from 437 participants. On average, a 1-min increase in total walking was associated with an increase in total PA of 1 min, measured by objective data, and 1.2-min, measured by self-reported data. A similar additive effect was consistently found with utilitarian, transportation, or job-related walking, measured by both objective and self-reported data. For recreational walking, the effect of change was mixed between objective and self-reported results. Both objective and self-reported data confirmed an additive effect of utilitarian and total walking on PA.

  2. A model for ball lightning

    International Nuclear Information System (INIS)

    Fryberger, D.

    1994-10-01

    A model for ball lightning (BL) is described. It is based upon the vorton model for elementary particles, which exploits the symmetry between electricity and magnetism. The core, or driving engine, of BL in this model is comprised of a vorton-antivorton plasma. The energy of BL, which derives from nucleon decay catalyzed by this plasma, leads, through various mechanisms, to BL luminosity as well as to other BL features. It is argued that this model could also be a suitable explanation for other luminous phenomena, such as the unidentified atmospheric light phenomena seen at Hessdalen. It is predicted that BL and similar atmospheric luminous phenomena should manifest certain features unique to this model, which would be observable with suitable instrumentation

  3. Effects of gamma irradiation on total polyphenols, radical scavenging activities and decolourization of Nelumbo nucifera extracts

    International Nuclear Information System (INIS)

    Jeong, Il Yun; Lee, Hyo Jung; Park, Yong Dae; Jin, Chang Hyun; Choi, Dae Seong; Byun, Myung Woo

    2009-01-01

    The ethanolic leaf extract of Nelumbo nucifera (NC) was exposed to γ-irradiation, and its antioxidant activities, total polyphenols and colour characteristics were studied to discern its potential ability as a food or cosmetic materials. The results demonstrated that the radical scavenging activities and total polyphenols of the γ-irradiated leaf extract of NC were not observed to be significantly different. However, γ-irradiation significantly increased the Hunter colour L*-value at doses of 20 and 50 kGy, while the Hunter colour b*-values were decreased under the same conditions.

  4. Effects of gamma irradiation on total polyphenols, radical scavenging activities and decolourization of Nelumbo nucifera extracts

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Il Yun [Radiation Research Center for Innovative Technology, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeong-up 580-185 (Korea, Republic of)], E-mail: iyjeong@kaeri.re.kr; Lee, Hyo Jung; Park, Yong Dae; Jin, Chang Hyun; Choi, Dae Seong; Byun, Myung Woo [Radiation Research Center for Innovative Technology, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeong-up 580-185 (Korea, Republic of)

    2009-07-15

    The ethanolic leaf extract of Nelumbo nucifera (NC) was exposed to {gamma}-irradiation, and its antioxidant activities, total polyphenols and colour characteristics were studied to discern its potential ability as a food or cosmetic materials. The results demonstrated that the radical scavenging activities and total polyphenols of the {gamma}-irradiated leaf extract of NC were not observed to be significantly different. However, {gamma}-irradiation significantly increased the Hunter colour L*-value at doses of 20 and 50 kGy, while the Hunter colour b*-values were decreased under the same conditions.

  5. Chapter 4: Measurements of total beta-activity in the fallout

    International Nuclear Information System (INIS)

    Duggleby, J.C.; Johannessen, J.C.; Kotler, L.H.; Stewart, F.M.

    1974-01-01

    In order to provide information on fresh fission products in fallout reaching Australia from nuclear tests being conducted by France in Polynesia, measurements were made of total beta activity in daily fallout deposition of 25 Australian sampling stations covering a three month period from 25 July to 23 October 1973. The methods employed to measure the radioactivity of the samples are described and the data on total beta-activity, and the calculated external gamma radiation doses from fresh fallout are presented. (R.L.)

  6. A Fossilized Energy Distribution of Lightning

    Science.gov (United States)

    Pasek, Matthew A.; Hurst, Marc

    2016-07-01

    When lightning strikes soil, it may generate a cylindrical tube of glass known as a fulgurite. The morphology of a fulgurite is ultimately a consequence of the energy of the lightning strike that formed it, and hence fulgurites may be useful in elucidating the energy distribution frequency of cloud-to-ground lightning. Fulgurites from sand mines in Polk County, Florida, USA were collected and analyzed to determine morphologic properties. Here we show that the energy per unit length of lightning strikes within quartz sand has a geometric mean of ~1.0 MJ/m, and that the distribution is lognormal with respect to energy per length and frequency. Energy per length is determined from fulgurites as a function of diameter, and frequency is determined both by cumulative number and by cumulative length. This distribution parallels those determined for a number of lightning parameters measured in actual atmospheric discharge events, such as charge transferred, voltage, and action integral. This methodology suggests a potential useful pathway for elucidating lightning energy and damage potential of strikes.

  7. A Fossilized Energy Distribution of Lightning.

    Science.gov (United States)

    Pasek, Matthew A; Hurst, Marc

    2016-07-28

    When lightning strikes soil, it may generate a cylindrical tube of glass known as a fulgurite. The morphology of a fulgurite is ultimately a consequence of the energy of the lightning strike that formed it, and hence fulgurites may be useful in elucidating the energy distribution frequency of cloud-to-ground lightning. Fulgurites from sand mines in Polk County, Florida, USA were collected and analyzed to determine morphologic properties. Here we show that the energy per unit length of lightning strikes within quartz sand has a geometric mean of ~1.0 MJ/m, and that the distribution is lognormal with respect to energy per length and frequency. Energy per length is determined from fulgurites as a function of diameter, and frequency is determined both by cumulative number and by cumulative length. This distribution parallels those determined for a number of lightning parameters measured in actual atmospheric discharge events, such as charge transferred, voltage, and action integral. This methodology suggests a potential useful pathway for elucidating lightning energy and damage potential of strikes.

  8. Rationales for the Lightning Launch Commit Criteria

    Science.gov (United States)

    Willett, John C. (Editor); Merceret, Francis J. (Editor); Krider, E. Philip; O'Brien, T. Paul; Dye, James E.; Walterscheid, Richard L.; Stolzenburg, Maribeth; Cummins, Kenneth; Christian, Hugh J.; Madura, John T.

    2016-01-01

    Since natural and triggered lightning are demonstrated hazards to launch vehicles, payloads, and spacecraft, NASA and the Department of Defense (DoD) follow the Lightning Launch Commit Criteria (LLCC) for launches from Federal Ranges. The LLCC were developed to prevent future instances of a rocket intercepting natural lightning or triggering a lightning flash during launch from a Federal Range. NASA and DoD utilize the Lightning Advisory Panel (LAP) to establish and develop robust rationale from which the criteria originate. The rationale document also contains appendices that provide additional scientific background, including detailed descriptions of the theory and observations behind the rationales. The LLCC in whole or part are used across the globe due to the rigor of the documented criteria and associated rationale. The Federal Aviation Administration (FAA) adopted the LLCC in 2006 for commercial space transportation and the criteria were codified in the FAA's Code of Federal Regulations (CFR) for Safety of an Expendable Launch Vehicle (Appendix G to 14 CFR Part 417, (G417)) and renamed Lightning Flight Commit Criteria in G417.

  9. On the initiation of lightning in thunderclouds.

    Science.gov (United States)

    Chilingarian, Ashot; Chilingaryan, Suren; Karapetyan, Tigran; Kozliner, Lev; Khanikyants, Yeghia; Hovsepyan, Gagik; Pokhsraryan, David; Soghomonyan, Suren

    2017-05-02

    The relationship of lightning and elementary particle fluxes in the thunderclouds is not fully understood to date. Using the particle beams (the so-called Thunderstorm Ground Enhancements - TGEs) as a probe we investigate the characteristics of the interrelated atmospheric processes. The well-known effect of the TGE dynamics is the abrupt termination of the particle flux by the lightning flash. With new precise electronics, we can see that particle flux decline occurred simultaneously with the rearranging of the charge centers in the cloud. The analysis of the TGE energy spectra before and after the lightning demonstrates that the high-energy part of the TGE energy spectra disappeared just after lightning. The decline of particle flux coincides on millisecond time scale with first atmospheric discharges and we can conclude that Relativistic Runaway Electron Avalanches (RREA) in the thundercloud assist initiation of the negative cloud to ground lightning. Thus, RREA can provide enough ionization to play a significant role in the unleashing of the lightning flash.

  10. Lightning protection design external tank /Space Shuttle/

    Science.gov (United States)

    Anderson, A.; Mumme, E.

    1979-01-01

    The possibility of lightning striking the Space Shuttle during liftoff is considered and the lightning protection system designed by the Martin Marietta Corporation for the external tank (ET) portion of the Shuttle is discussed. The protection system is based on diverting and/or directing a lightning strike to an area of the spacecraft which can sustain the strike. The ET lightning protection theory and some test analyses of the system's design are reviewed including studies of conductivity and thermal/stress properties in materials, belly band feasibility, and burn-through plug grounding and puncture voltage. The ET lightning protection system design is shown to be comprised of the following: (1) a lightning rod on the forward most point of the ET, (2) a continually grounded, one inch wide conductive strip applied circumferentially at station 371 (belly band), (3) a three inch wide conductive belly band applied over the TPS (i.e. the insulating surface of the ET) and grounded to a structure with eight conductive plugs at station 536, and (4) a two inch thick TPS between the belly bands which are located over the weld lands.

  11. Lightning and Electric Field Structure of a Squall Line During TELEX

    Science.gov (United States)

    Macgorman, D.; Rust, D.; Bruning, E.; Ramig, N.; Apostolakopoulos, I.; Schuur, T.; Biggerstaff, M.; Straka, J.; Krehbiel, P.; Rison, B.; Hamlin, T.

    2004-12-01

    During the 2004 field program for the Thunderstorm Electrification and Lightning Experiment (TELEX), simultaneous electric field soundings, three-dimensional lightning mapping observations, high-resolution Doppler radar data, polarimetric radar data, and environmental soundings were acquired for several mesoscale convective systems, supercell storms, and non-severe thunderstorms. The overall data set was of particularly high quality for a squall line that produced frequent lightning in southern and central Oklahoma on the morning of 19 June 2004. A total of five balloon-borne electric field soundings were launched into the leading line of convection and into the trailing stratiform region. Two 5-cm wavelength mobile Doppler radars (SMART-R's) provided coordinated volume scans every 3 min throughout the period of operations. Furthermore, all operations were well within range of the 10-cm wavelength polarimetric radar and the three-dimensional lightning mapping array. This presentation will emphasize lightning mapping and electric field observations to characterize the electrical behavior of the convective line and the stratiform region.

  12. Analysis of antioxidant activity and total phenolic content of some homoeopathic mother tinctures

    Directory of Open Access Journals (Sweden)

    Saeed Ahmad

    2017-01-01

    Full Text Available Background: Antioxidant compounds are widely used in health protection. Homoeopathic mother tinctures are commonly prescribed for prevention and cure of many illnesses. Objective: The present study focused to determine the antioxidant potential of six commonly prescribed mother tinctures. i.e. Syzygium jambolanum, Damiana, Cinchona officinalis, Chelidonium majus, Convallaria majalis, Coca. Materials and Methods: Antioxidant activity was estimated by 2,2-diphenyl-1-picrylhydrazyl (DPPH inhibition assay. A volume of 0.1 mM solution of DPPH was used while mother tinctures (5, 2.5, and 1.25 μl volumes were used for estimating antioxidant activity. Quercetin was taken as a standard control in antioxidant activity. Total phenolic content was measured by Folin–Ciocalteu reagent assay. Total phenolic content of mother tinctures was measured in comparison to gallic acid. Results: Results of the study showed the significant antioxidant activity and high total phenolic content of all tested mother tinctures in the following order: Syzygium jambolanum, Damiana, Cinchona officinalis, Chelidonium majus, Convallaria majalis, Coca. Conclusion: Antioxidant potential of mother tinctures is related to total phenolic content present in them, and their role in prevention and cure of diseases may link through their antioxidant activity. Among six selected mother tinctures, S. jambolanum has highest antioxidant potential.

  13. Antioxidant Activity, Total Phenolic and Flavonoid Contents of Three Onobrychis Species from Iran

    Directory of Open Access Journals (Sweden)

    Roya Karamian , Mostafa Asadbegy

    2016-06-01

    Full Text Available Background: Plant phenolic compounds are a main group of plant natural products and flavonoids are the largest and best studied natural phenols. These substances possess a series of biological properties and act on biological systems as antioxidants. In present research, the aim is to determine in vitro total phenolics content and antioxidant activity of the methanolic extracts of three Onobrychis species belonging to the family Fabaceae, namely O. sosnovskyi Grossh., O. viciifolia Scop. and O. melanotricha Boiss. Furthermore, an attempt was made to identify any correlations between total phenolic content of the extracts with their antioxidant activities Methods: Total phenol and flavonoid contents of the extracts were determined by Folin-Ciocalteu and aluminum chloride methods, respectively. Antioxidant activity was evaluated by three different test systems, namely 2, 2-diphenyl-1-picrylhydrazyl free radical scavenging (DPPH, metal-chelation activity and ß-carotene/linoleic acid model. Results: Results indicated that O. viciifolia extract contains the highest total phenolic content (10.38 ± 0.33mg GAE/g of dry extract. However, the species are not remarkable different (P 0.55 to 0.98. Conclusion: Our results showed that the examined Onobrychis extracts represent strong antioxidant activity; hence, they can be suggested as antioxidant agents for special use in future.

  14. Antioxidant Activity and Total Phenolic and Flavonoid Contents of Hieracium pilosella L. Extracts

    Directory of Open Access Journals (Sweden)

    Jasna Čanadanovic-Brunet

    2009-07-01

    Full Text Available The antioxidant activity ofwater, ethanol and methanol Hieracium pilosella L.extracts is reported. The antioxidative activity was tested by spectrophotometrically measuring their ability to scavenge a stable DPPH· free radical and a reactive hydroxyl radical trapped by DMPO during the Fenton reaction, using the ESR spectroscopy. Total phenolic content and total flavonoid content were evaluated according to the Folin-Ciocalteu procedure, and a colorimetric method, respectively. A HPLC method was used for identification of some phenolic compounds (chlorogenic acid, apigenin-7-O-glucoside and umbelliferone. The antioxidant activity of the investigated extracts slightly differs depending on the solvent used. The concentration of 0.30 mg/mL of water, ethanol and methanol extract is less effective in scavenging hydroxyl radicals (56.35, 58.73 and 54.35%, respectively in comparison with the DPPH· radical scavenging activity (around 95% for all extracts. The high contents of total phenolic compounds (239.59–244.16 mg GAE/g of dry extract and total flavonoids (79.13–82.18 mg RE/g of dry extract indicated that these compounds contribute to the antioxidative activity.

  15. Situational Lightning Climatologies for Central Florida: Phase V

    Science.gov (United States)

    Bauman, William H., III

    2011-01-01

    The AMU added three years of data to the POR from the previous work resulting in a 22-year POR for the warm season months from 1989-2010. In addition to the flow regime stratification, moisture and stability stratifications were added to separate more active from less active lighting days within the same flow regime. The parameters used for moisture and stability stratifications were PWAT and TI which were derived from sounding data at four Florida radiosonde sites. Lightning data consisted of NLDN CG lightning flashes within 30 NM of each airfield. The AMU increased the number of airfields from nine to thirty-six which included the SLF, CCAFS, PAFB and thirty-three airfields across Florida. The NWS MLB requested the AMU calculate lightning climatologies for additional airfields that they support as a backup to NWS TBW which was then expanded to include airfields supported by NWS JAX and NWS MFL. The updated climatologies of lightning probabilities are based on revised synoptic-scale flow regimes over the Florida peninsula (Lambert 2007) for 5-, 10-, 20- and 30-NM radius range rings around the thirty-six airfields in 1-, 3- and 6-hour increments. The lightning, flow regime, moisture and stability data were processed in S-PLUS software using scripts written by the AMU to automate much of the data processing. The S-PLUS data files were exported to Excel to allow the files to be combined in Excel Workbooks for easier data handling and to create the tables and charts for the Gill. The AMU revised the Gill developed in the previous phase (Bauman 2009) with the new data and provided users with an updated HTML tool to display and manipulate the data and corresponding charts. The tool can be used with most web browsers and is computer operating system independent. The AMU delivered two Gills - one with just the PWAT stratification and one with both the PWAT and TI stratifications due to insufficient data in some of the PWATITI stratification combinations. This will allow

  16. Laboratory simulations of volcanic ash charging and conditions for volcanic lightning on Venus

    Science.gov (United States)

    Airey, Martin; Warriner-Bacon, Elliot; Aplin, Karen

    2017-04-01

    Lightning may be important in the emergence of life on Earth and elsewhere, as significant chemical reactions occur in the superheated region around the lightning channel. This, combined with the availability of phosphates in volcanic clouds, suggests that volcanic lightning could have been the catalyst for the formation of biological compounds on the early Earth [1]. In addition to meteorological lightning, volcanic activity also generates electrical discharges within charged ash plumes, which can be a significant contributor to atmospheric electricity on geologically active planets. The physical properties of other planetary atmospheres, such as that of Venus, have an effect on the processes that lead to the generation of volcanic lightning. Volcanism is known to have occurred on Venus in the past, and recent observations made by ESA's Venus Express satellite have provided evidence for currently active volcanism [2-4], and lightning discharges [e.g. 5]. Venusian lightning could potentially be volcanic in origin, since no meteorological mechanisms are known to separate charge effectively in its clouds [6]. The hunt for further evidence for lightning at Venus is ongoing, for example by means of the Lightning and Airglow Camera (LAC) [7] on Akatsuki, the current JAXA mission at Venus. Our laboratory experiments simulate ash generation and measure electrical charging of the ash under typical atmospheric conditions on Earth and Venus. The study uses a 1 litre chamber, which, when pressurised and heated, can simulate the high-pressure, high-temperature, carbon dioxide-dominated atmosphere of Venus at 10 km altitude ( 5 MPa, 650 K). A key finding of previous work [8] is that ash plume-forming eruptions are more likely to occur at higher altitudes such as these on Venus. The chamber contains temperature/pressure monitoring and logging equipment, a rock collision apparatus (based on [9]) to generate the charged rock fragments, and charge measurement electrodes connected

  17. Lightning NOx Production in CMAQ Part I – Using Hourly NLDN Lightning Strike Data

    Science.gov (United States)

    Lightning-produced nitrogen oxides (NOX=NO+NO2) in the middle and upper troposphere play an essential role in the production of ozone (O3) and influence the oxidizing capacity of the troposphere. Despite much effort in both observing and modeling lightning NOX during the past dec...

  18. Status on the Zeus lightning network in Brazil and its application to the electrical sector of COELCE - the Energy Company from Ceara state

    Energy Technology Data Exchange (ETDEWEB)

    Morales Rodriguez, Carlos Augusto [Universidade de Sao Paulo (USP), SP (Brazil)], E-mail: morales@model.iag.usp.br; Sales, Francisco; Pinheiro, Francisco Geraldo [Universidade Estadual do Ceara (UECE), CE (Brazil)], E-mail: fsales@uece.br; Camara, Keyla Sampaio [Companhia de Energetica do Estado do Ceara (COELCE), Fortaleza, CE (Brazil)], Emails: keyla@coelce.com.br, fgmpinheiro@uece.br; Anagnostou, Emmanouil E. [University of Connecticut, Storrs, CT (United States)], E-mail: manos@engr.uconn.edu

    2007-07-01

    This paper presents the deployment and new perspectives of the ZEUS VLF long range lightning monitoring network that has been established in Brazil after the support of the Research and Development Program of the 'Companhia Energetica do Ceara-(COELCE)'. The ZEUS network measures radio noise emitted by lightning that propagates through the ionosphere-earth surface waveguide up to thousands of kilometers. Two new VLF antennas have been installed in Fortaleza (Ceara) and Cachoeira Paulista (Sao Paulo) Brazil in the first semester of 2006 and were integrated with the 4 sensor installed in Africa and one in the Caribbean. Based on this new configuration, ZEUS is continuing measuring lightning discharges over South and North America, the Atlantic Ocean and Africa. Preliminary validation analysis using the data from the Brazilian Lightning Detection Network (RINDAT), National Lightning Detection Network (NLDN) of USA, and Lightning Imaging Sensor (LIS) on board the Tropical Rainfall Measuring Mission were employed to retrieve the location accuracy during the period of August through November of 2006. The location accuracy is based on coincident timing matches been the sferics measurements observed by ZEUS against the measurements of RINDAT, NLDN and LIS. Based on this new ZEUS configuration, the preliminary validation shows that ZEUS has location accuracy between 10-50 km over Brazil, 5-25 km in Africa, 70-100 km over the southern USA, and 5-25 km in the Atlantic Ocean. The measurements from August through November of 2006 show that the main lightning activity is located in the Western Amazon, Western and Central Africa, Central America, Colombia, Florida and Caribbean regions, which agrees with the lightning maps derived with LIS for the same time period. Finally, since ZEUS is been employed by COELCE, some lightning and thunderstorm products are been developed to help the improvement of their system over the states of Ceara, for example: lightning

  19. Systematic and Stereoselective Total Synthesis of Mannosylerythritol Lipids and Evaluation of Their Antibacterial Activity.

    Science.gov (United States)

    Nashida, Junki; Nishi, Nobuya; Takahashi, Yoshiaki; Hayashi, Chigusa; Igarashi, Masayuki; Takahashi, Daisuke; Toshima, Kazunobu

    2018-03-13

    The total synthesis of the 20 homogeneous members of mannosylerythritol lipids (MELs) with different alkyl chain lengths was effectively and systematically accomplished from a strategically designed common key intermediate that was stereoselectively constructed by the borinic acid catalyzed β-mannosylation reaction. In addition, their antibacterial activities against Gram-positive bacteria were evaluated. Our results demonstrated that not only the length of the alkyl chains but also the pattern of Ac groups on the mannose moiety were important factors for antibacterial activity.

  20. Development of Lightning Observation Network in the Western Pacific Region for the Intensity Prediction of Severe Weather

    Science.gov (United States)

    Sato, M.; Takahashi, Y.; Yamashita, K.; Kubota, H.; Hamada, J. I.; Momota, E.; Marciano, J. J.

    2017-12-01

    Lightning activity represents the thunderstorm activity, that is, the precipitation an