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Sample records for supercell thunderstorms produced

  1. Spatial and temporal characteristics of VHF radiation source produced by lightning in supercell thunderstorms

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yijun; MENG Qing; P. R. Krehbiel; LIU Xinsheng; ZHOU Xiuji

    2004-01-01

    The three-dimensional temporal and spatial characteristics of VHF radiation events produced by lightning discharges in three supercell thunderstorms have been analyzed based on the data measured by the lightning mapping array system with high time and space resolution. The results indicate that lightning hole (lighting free region) with about 5-6 km in diameter or lighting ring (annular lighting free region) is associated with the strong updraft in thunderstorm. The lasting time of lightning holes is either short or long, being about 20 min in a tornado-producing thunderstorm. The lightning holes appear before the occurrence of tornado. The lightning hole is the most obvious during the occurrence of tornado and some self-existent lighting radiation events appear at a height of 15-16 km. The lightning channels of inter-cloud (IC) lightning discharge exhibit clockwise rotary structures and do not have clear bilevel structures in the vicinity of the tornado. The lightning holes are corresponding to the strong updraft region. The temporal and spatial distribution of lightning radiation events reveals the structure of strong updraft in supercell thunderstorms.Positive cloud-to-ground (CG) lightning discharges dominate in these thunderstorms and the peak of positive CG lightning flash rate appears, with the maximum of 6 per minute, after or before the occurrence of tornado.

  2. The Effects of Orographic Geometry on Supercell Thunderstorms

    CERN Document Server

    Smith, Galen M

    2016-01-01

    The effect of elongated bell-shaped mountain orientation on supercell thunderstorms is numerically investigated using the Bryan Cloud Model 1 (CM1). The orography is varied by three mountain heights and is varied in four different positions, effectively producing 12 different terrain configurations. It is found that the different orientations produce variations in the supercell life cycle with shorter cycles for higher inflow rates. Furthermore, these cycles are associated with the storm reaching its minimum intensity just after a peak rain period. Moreover, the effect of stronger inflow was seen before direct storm-terrain interactions started. The higher inflow also played a significant role in increasing rainfall rate and areal extent, to the point that further convection, associated with the cold pool, was triggered adding to rainfall amount. Using a stricter form of the National Weather Service Tornado Detection Algorithm to investigate the tornadic nature of simulated supercells; it is found that terrai...

  3. Charge structures and cloud-to-ground lightning discharges characteristics in two supercell thunderstorms

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yijun; MENG Qing; LU Weitao; Paul Krehbiel; LIU Xinsheng; ZhOU Xiuji

    2006-01-01

    The charge structures and temporal and spatial characteristics of cloud-to-ground (CG) lightning discharges in two supercell thunderstorms have been analyzed based on the data of three-dimen- sional VHF radiation sources with high time and space resolution produced by lightning discharges. The results indicate that the charge structures in main part (convective region) of the thunderstorms were inverted tripole while a number of positive CG lightning discharges were occurring in the two thunderstorms. The positive CG lightning discharges occurred in main part of the thunderstorms and originated from the positive charge region located at the middle part of the thunderstorms. While a number of negative CG lightning discharges were occurring, the negative CG lightning discharges occurred in the anvil of the thunderstorm. The charge structure is inverted dipole in the region due to the slant of charge structure in main region toward anvil region. The negative charge region located at the upper part of anvil produced a lot of negative CG lightning discharges. No or less CG lighting was produced directly by the charge region located at the lower part of the thunderstorm. The charge region in lower part of the thunderstorm plays an important role for the occurrence of CG lightning from charge region above it.

  4. Proximity sounding analysis for derechos and supercells: an assessment of similarities and differences

    Science.gov (United States)

    Doswell, Charles A.; Evans, Jeffry S.

    Proximity soundings (within 2 h and 167 km) of derechos (long-lived, widespread damaging convective windstorms) and supercells have been obtained. More than 65 derechos, accompanied by 115 proximity soundings, are identified during the years 1983 to 1993. The derechos have been divided into categories according to the synoptic situation: strong forcing (SF), weak forcing (WF), and "hybrid" cases (which are neither weakly nor strongly forced). Nearly 100 supercell proximity soundings have been found for the period 1998 to 2001, subdivided into nontornadic and tornadic supercells; tornadic supercells were further subdivided into those producing significant (>F1 rating) tornadoes and weak tornadoes (F0-F1 rating). WF derecho situations typically are characterized by warm, moist soundings with large convective available potential instability (CAPE) and relatively weak vertical wind shear. SF derechos usually have stronger wind shears, and cooler and less moist soundings with lower CAPE than the weakly forced cases. Most derechos exhibit strong storm-relative inflow at low levels. In WF derechos, this is usually the result of rapid convective system movement, whereas in SF derechos, storm-relative inflow at low levels is heavily influenced by relatively strong low-level windspeeds. "Hybrid" cases collectively are similar to an average of the SF and WF cases. Supercells occur in environments that are not all that dissimilar from those that produce SF derechos. It appears that some parameter combining instability and deep layer shear, such as the Energy-Helicity Index (EHI), can help discriminate between tornadic and nontornadic supercell situations. Soundings with significant tornadoes (F2 and greater) typically show high 0-1 km relative humidities, and strong 0-1 km shear. Results suggest it may not be easy to forecast the mode of severe thunderstorm activity (i.e., derecho versus supercell) on any particular day, given conditions that favor severe thunderstorm activity

  5. Composites of Heavy Rain Producing Elevated Thunderstorms in the Central United States

    Directory of Open Access Journals (Sweden)

    Laurel P. McCoy

    2017-01-01

    Full Text Available Composite analyses of the atmosphere over the central United States during elevated thunderstorms producing heavy rainfall are presented. Composites were created for five National Weather Service County Warning Areas (CWAs in the region. Events studied occurred during the warm season (April–September during 1979–2012. These CWAs encompass the region determined previously to experience the greatest frequency of elevated thunderstorms in the United States. Composited events produced rainfall of >50 mm 24 hr−1 within the selected CWA. Composites were generated for the 0–3 hr period prior to the heaviest rainfall, 6–9 hours prior to it, and 12–15 hours prior to it. This paper focuses on the Pleasant Hill, Missouri (EAX composites, as all CWA results were similar; also these analyses focus on the period 0–3 hours prior to event occurrence. These findings corroborate the findings of previous authors. What is offered here that is unique is (1 a measure of the interquartile range within the composite mean fields, allowing for discrimination between variable fields that provided a strong reliable signal, from those that may appear strong but possess large variability, and (2 composite soundings of two subclasses of elevated thunderstorms. Also, a null case (one that fits the composite but failed to produce significant rainfall is also examined for comparison.

  6. Numerical Investigation on the Growth of Large Hail in a Simulated Supercell Thunderstorm%超级单体风暴中大冰雹增长机制的模拟研究

    Institute of Scientific and Technical Information of China (English)

    陈宝君; 郑凯琳; 郭学良

    2012-01-01

    A three-dimensional convective cloud model with a hail-bin microphysics scheme and a hail growth model were used to further investigate the growth mechanism of large hail in supercell storms. The observed supercell features such as quasi-steady mesocyclone, a pronounced bounded weak echo region and a forward overhang were reproduced well by the simulation. During the storm developing stage, hail embryos were produced mainly by the freezing process of raindrops and occurred at the top of the main updraft region and the mid- to upper-portion of the storm from the northwest flank of the main updraft region. Approximately 7%-8% of hail embryos forming at the developing stage continued to grow into hail larger than 10 mm in diameter; only 1% of hail embryos ultimately achieved diameters of 20 mm. Most of the largest hailstones grew from millimeter-size embryos that originated in the upper-level region around the north flank of the updraft and thereafter entered the main updraft cyclonically and grew into large hailstones in a single up-down path. Other embryos originated in the upper-level region of the northwest flank around the main updraft and grew into large hailstones in a down-up-down path along the updraft edge cyclonically. These results suggest that there are two growth paths for large hailstones in supercell storms.%为调查超级单体中大冰雹的运行增长机制,使用三维冰雹分档对流云模式结合三维粒子运行增长模式,对一例超级单体风暴进行了数值模拟.实测风暴的结构如中气旋、弱回波区、前悬回波等被很好地模拟再现,显示了模式对超级单体具有良好的模拟能力.雹胚在风暴发展阶段由过冷雨滴冻结产生,主要分布在主上升气流区上部,在主上升气流区西北侧中高层也有相当数量的雹胚粒子,冰雹主要分布在主上升气流区东侧.风暴发展阶段产生的雹胚有7%~8%增长到1 cm以上,1%左右增长到2 cm以上,这些大冰雹

  7. Observation of successive TGFs produced by the same thunderstorm systems throughout their lifetime

    Science.gov (United States)

    Ursi, Alessandro; Marisaldi, Martino; Tavani, Marco; Argan, Andrea; Dietrich, Stefano; Casella, Daniele; Sanò, Paolo

    2016-04-01

    Since their discovery in early 1990s, Terrestrial Gamma-ray Flashes (TGFs) exhibited a clear correlation with thunderstorm activity. The elusive nature of these events and the strong absorption of gamma-rays in the lowest layers of the atmosphere dramatically limits our observation of this phenomenon: the few missions currently detecting TGFs are probably revealing just the tip of the iceberg of a much wider population. Theoretical models, radar measurements and cross-correlations with radio waves emitted by lightning strokes suggest every storm could, in principle, produce a large number of gamma flashes throughout its entire lifetime: however, observation of more TGFs from the same thunderstorm system, even after several hours, is difficult to perform, because successive passes on the same latitude region by high-inclination orbit satellites are shifted westward by ~25°. In this perspective, the AGILE mission has a privileged role, thanks to its unique quasi equatorial (2.5° inclination) orbit, that allows for the follow-up of the same geographic region on the equator at each orbital passage. In more than 8 years activity, we identify tens of cases of more TGFs coming from the same thunderstorm system, either during the same passage, or in the successive passages. We take advantage of data acquired by meteorological satellites to characterize the meteorological scenario associated to these events.

  8. Numerical Study on a Severe Downburst-Producing Thunderstorm on 23 August 2001 in Beijing

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A thunderstorm that produced severe wind, heavy rain and hail on 23 August 2001 in Beijing was studied by a three-dimensional cloud model including hail-bin microphysics. This model can provide important information for hail size at the surface, which is not available in hail parameterization cloud models. The results shows that the cloud model, using hail-bin microphysics, could reasonably reflect the storm's characteristics such as life cycle, rainfall distribution and the diameter of the hailstones and also can reproduce developing processes of downbursts, where they can then be compared with the observed features of the storm. The downburst formation mechanism was investigated based on the cloud microphysics of the simulated storm and it was found that the downburst was primarily produced by hail-loading and enhanced by cooling processes that were due to hail melting and rain evaporation. The loading and melting of hail played crucial roles in the formation of downbursts within the storm.

  9. Numerical Simulation of a Tornado Generating Supercell

    Science.gov (United States)

    Proctor, Fred H.; Ahmad, Nashat N.; LimonDuparcmeur, Fanny M.

    2012-01-01

    The development of tornadoes from a tornado generating supercell is investigated with a large eddy simulation weather model. Numerical simulations are initialized with a sounding representing the environment of a tornado producing supercell that affected North Carolina and Virginia during the Spring of 2011. The structure of the simulated storm was very similar to that of a classic supercell, and compared favorably to the storm that affected the vicinity of Raleigh, North Carolina. The presence of mid-level moisture was found to be important in determining whether a supercell would generate tornadoes. The simulations generated multiple tornadoes, including cyclonic-anticyclonic pairs. The structure and the evolution of these tornadoes are examined during their lifecycle.

  10. The formation process and cloud physical characteristics for a typical downburst-producing thunderstorm in Beijing

    Institute of Scientific and Technical Information of China (English)

    GUO Xueliang; FU Danhong

    2003-01-01

    The formation process and characteristics of cloud physical structure of a severe thunderstorm accompanied with strong wind on 23 August, 2001 in Beijing was studied using PSU/NCAR mesoscale model (MM5)coupling with a severe storm model with hail-bin microphysics. The results show that the specific topography and distribution features of cold/warm current in the Beijing region played prominent roles in forming, developing and maintaining the severe storm. Due to solar radiation heating and topographic lifting, the convective cells were easily formed when the westerly airflow passed over high mountainous regions in Beijing. The warm and wet air entered the cloud from its frontage and enhanced the convection, and formed a large amount of graupel/hail particles at the middle and upper portion of the clouds. The precipitation was primarily formed due to melting of graupel/hail particles. The strong downdraft was mainly produced by negative buoyancy due to loading,melting of graupel/hail particles as well as evaporative cooling of rain water. The divergent airflow induced by the strong downdraft led to the disastrous burst winds at the surface and also forced lifting of warm and wet airflow in the moving direction of the storm and formed new clouds that further promoted and maintained the storm development.

  11. Measurements of reactive nitrogen produced by tropical thunderstorms during BIBLE-C

    Science.gov (United States)

    Koike, M.; Kondo, Y.; Kita, K.; Takegawa, N.; Nishi, N.; Kashihara, T.; Kawakami, S.; Kudoh, S.; Blake, D.; Shirai, T.; Liley, B.; Ko, M.; Miyazaki, Y.; Kawasaki, Z.; Ogawa, T.

    2007-09-01

    The Biomass Burning and Lightning Experiment phase C (BIBLE-C) aircraft mission was carried out near Darwin, Australia (12°S, 131°E) in December 2000. This was the first aircraft experiment designed to estimate lightning NO production rates in the tropics, where production is considered to be most intense. During the two flights (flights 10 and 13 made on December 9 and 11-12, respectively) enhancements of NOx (NO + NO2) up to 1000 and 1600 parts per trillion by volume (pptv, 10-s data) were observed at altitudes between 11.5 and 14 km. The Geostationary Meteorological Satellite (GMS) cloud (brightness temperature) data and ground-based lightning measurements by the Global Positioning and Tracking System (GPATS) indicate that there were intensive lightning events over the coast of the Gulf of Carpentaria, which took place upstream from our measurement area 10 to 14 h prior to the measurements. For these two flights, air in which NOx exceeded 100 pptv extended over 620 × 140 and 400 × 170 km2 (wind direction × perpendicular direction), respectively, suggesting a significant impact of lightning NO production on NOx levels in the tropics. We estimate the amount of NOx observed between 11.5 and 14 km produced by the thunderstorms to be 3.3 and 1.8 × 1029 NO molecules for flights 10 and 13, respectively. By using the GPATS lightning flash count data, column NO production rates are estimated to be 1.9-4.4 and 21-49 × 1025 NO molecules per single flash for these two flight data sets. In these estimations, it is assumed that the column NO production between 0 and 16 km is greater than the observed values between 11.5 and 14 km by a factor of 3.2, which is derived using results reported by Pickering et al. (1998). There are however large uncertainties in the GPATS lightning data in this study and care must be made when the production rates are referred. Uncertainties in these estimates are discussed. The impact on the ozone production rate is also described.

  12. Thunderstorm risk monitoring service

    Science.gov (United States)

    Brovelli, P.; Arbogast, E.; Bouzom, M.; Reynaud, J.; Autones, F.; Guillou, Y.; Bernard-Bouissières, I.; Sénési, S.

    2009-09-01

    The SIGnificant weather Object Oriented Nowcasting System (SIGOONS) is based on a scheme combining forecaster's expertise and observation data advanced automated processing ; it is an object oriented system for detection and forecasting significant phenomena at a few hours range. Downstream, SIGOONS feed warnings automated generation. Today, SIGOONS manages thunderstorms only. SIGOONS development follows two streams: o Operating a "fully automated” SIGOONS to produce thunderstorm risk warnings, in order to demonstrate the capability of warnings service for Météo-France customers at the short nowcasting range. At this stage of automation, warnings are limited to a range of one hour. o Ensure interaction feasibility and efficiency to match forecaster's expertise on thunderstorms forecasting, for improving warnings timeliness, intensity and location. The 2009 SIGOONS schedule was populated by the marketing of the thunderstorms warnings service named "Thunderstorm risk monitoring service” and by experiments with the seven regional forecasting services in real-time to assess adding expert value to warnings. Beyond, the goals are to operate thunderstorms expertise routinely using SIGOONS, to improve automation in thunderstorms description using new radar data (3D, doppler, polarization data) and mesoscale numerical weather prediction data, to introduce a probabilistic description of warnings location and intensity, and to manage another phenomena, namely the strong wind events.

  13. A Thermodynamic, kinematic and microphysical analysis of a jet and gigantic jet-producing Florida thunderstorm

    Science.gov (United States)

    Lazarus, S. M.; Splitt, M. E.; Brownlee, James; Spiva, Nicholas; Liu, Ningyu

    2015-08-01

    This paper presents a meteorological analysis of a storm that produced two jets, four gigantic jets (GJ), and a starter, which were observed by two radars as well as the Kennedy Space Center 4-Dimensional Lightning Surveillance System on 3 August 2013 in Central Florida. The work is the first application of dual polarization data to a jet-producing storm and is the fifth case related to a tropical disturbance. The storm environment is consistent with the moist tropical paradigm that characterizes about three quarters of the surface and aircraft observed jet and GJ events. The most unstable (MU) convective available potential energy is not unusual for Florida summer convection and is below the climatological mean for these events. An unusual speed shear layer is located near the storm equilibrium level (EL) and the storm exhibits a tilted structure with CGs displaced upshear. The turbulence, as measured by the eddy dissipation rate, is extreme near the storm top during the event window, consistent with the GJ mixing hypothesis. The individual events are collocated with, and track along, the center axis of the divergent outflow at the EL and occur within the region of the coldest GOES IR temperatures—placing the events within the overshoot. The dual polarization data indicate a deep graupel column, extending above the mixed phase layer, to a 13 km altitude.

  14. Cape Kennedy Thunderstorms Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Cape Kennedy Thunderstorms Data contains an account of all thunderstorms reported in weather observations taken at Cape Kennedy Air Force Station, Florida between...

  15. Spectrum of infrasound radiation from supercell storms

    CERN Document Server

    Akhalkatsi, Mariam

    2010-01-01

    We consider the generation of acoustic waves by turbulent convection and perform spectral analysis of a monopole source of sound related to the heat production by condensation of moisture. A quantitative explanation of the correlation between intensity of infrasound generated by supercell storms and later tornado formation is given. It is shown that low lifting condensation level (LCL) and high values of convective available potential energy (CAPE), which are known to favor significant tornadoes, also lead to a strong enhancement of supercell's low frequency acoustic radiation.

  16. Positrons observed to originate from thunderstorms

    Science.gov (United States)

    Fishman, Gerald J.

    2011-05-01

    Thunderstorms are the result of warm, moist air moving rapidly upward, then cooling and condensing. Electrification occurs within thunderstorms (as noted by Benjamin Franklin), produced primarily by frictional processes among ice particles. This leads to lightning discharges; the types, intensities, and rates of these discharges vary greatly among thunderstorms. Even though scientists have been studying lightning since Franklin's time, new phenomena associated with thunderstorms are still being discovered. In particular, a recent finding by Briggs et al. [2011], based on observations by the Gamma-Ray Burst Monitor (GBM) instrument on NASA's satellite-based Fermi Gamma-ray Space Telescope (Fermi), shows that positrons are also generated by thunderstorms. Positrons are the antimatter form of electrons—they have the same mass and charge as an electron but are of positive rather than negative charge; hence the name positron. Observations of positrons from thunderstorms may lead to a new tool for understanding the electrification and high-energy processes occurring within thunderstorms. New theories, along with new observational techniques, are rapidly evolving in this field.

  17. 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.

  18. 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.

  19. Summertime Thunderstorms Prediction in Belarus

    Science.gov (United States)

    Lapo, Palina; Sokolovskaya, Yaroslava; Krasouski, Aliaksandr; Svetashev, Alexander; Turishev, Leonid; Barodka, Siarhei

    2015-04-01

    Mesoscale modeling with the Weather Research & Forecasting (WRF) system makes it possible to predict thunderstorm formation events by direct numerical simulation. In the present study, we analyze the feasibility and quality of thunderstorm prediction on the territory of Belarus for the summer period of 2014 based on analysis of several characteristic parameters in WRF modeling results that can serve as indicators of thunderstorms formation. These parameters include vertical velocity distribution, convective available potential energy (CAPE), K-index, SWEAT-index, Thompson index, lifted condensation level (LCL), and others, all of them being indicators of favorable atmospheric conditions for thunderstorms development. We perform mesoscale simulations of several cases of thunderstorm development in Belarus with WRF-ARW modeling system using 3 km grid spacing, WSM6 microphysics parameterization and explicit convection (no convective parameterization). Typical modeling duration makes 48 hours, which is equivalent to next-day thunderstorm prediction in operational use. We focus our attention to most prominent cases of intense thunderstorms in Minsk. For validation purposes, we use radar and satellite data in addition to surface observations. In summertime, the territory of Belarus is quite often under the influence of atmospheric fronts and stationary anticyclones. In this study, we subdivide thunderstorm cases under consideration into 2 categories: thunderstorms related to free convection and those related to forced convection processes. Our aim is to study the differences in thunderstorm indicator parameters between these two categories of thunderstorms in order to elaborate a set of parameters that can be used for operational thunderstorm forecasting. For that purpose, we analyze characteristic features of thunderstorms development on cold atmospheric fronts as well as thunderstorms formation in stable air masses. Modeling results demonstrate good predictive skill

  20. Cosmic Rays in Thunderstorms

    Science.gov (United States)

    Buitink, Stijn; Scholten, Olaf; van den Berg, Ad; Ebert, Ute

    2013-04-01

    Cosmic Rays in Thunderstorms Cosmic rays are protons and heavier nuclei that constantly bombard the Earth's atmosphere with energies spanning a vast range from 109 to 1021 eV. At typical altitudes up to 10-20 km they initiate large particle cascades, called extensive air showers, that contain millions to billions of secondary particles depending on their initial energy. These particles include electrons, positrons, hadrons and muons, and are concentrated in a compact particle front that propagates at relativistic speed. In addition, the shower leaves behind a trail of lower energy electrons from ionization of air molecules. Under thunderstorm conditions these electrons contribute to the electrical and ionization processes in the cloud. When the local electric field is strong enough the secondary electrons can create relativistic electron run-away avalanches [1] or even non-relativistic avalanches. Cosmic rays could even trigger lightning inception. Conversely, strong electric fields also influence the development of the air shower [2]. Extensive air showers emit a short (tens of nanoseconds) radio pulse due to deflection of the shower particles in the Earth's magnetic field [3]. Antenna arrays, such as AERA, LOFAR and LOPES detect these pulses in a frequency window of roughly 10-100 MHz. These systems are also sensitive to the radiation from discharges associated to thunderstorms, and provide a means to study the interaction of cosmic ray air showers and the electrical processes in thunderstorms [4]. In this presentation we discuss the involved radiation mechanisms and present analyses of thunderstorm data from air shower arrays [1] A. Gurevich et al., Phys. Lett. A 165, 463 (1992) [2] S. Buitink et al., Astropart. Phys. 33, 1 (2010) [3] H. Falcke et al., Nature 435, 313 (2005) [4] S. Buitink et al., Astron. & Astrophys. 467, 385 (2007)

  1. Lightning-produced NOx over Brazil during TROCCINOX: Airborne measurements in tropical and subtropical thunderstorms and the importance of mesoscale convective systems

    Directory of Open Access Journals (Sweden)

    C. Schwierz

    2007-02-01

    Full Text Available During the TROCCINOX field experiments in February–March 2004 and February 2005, airborne in situ measurements of NO, NOy, CO, and O3 mixing ratios and the J(NO2 photolysis rate were carried out in the anvil outflow of thunderstorms over southern Brazil. Both tropical and subtropical thunderstorms were investigated, depending on the location of the South Atlantic convergence zone. Tropical air masses were discriminated from subtropical ones according to the higher equivalent potential temperature (Θe in the lower and mid troposphere, the higher CO mixing ratio in the mid troposphere, and the lower wind velocity and proper wind direction in the upper troposphere. During thunderstorm anvil penetrations, typically at 20–40 km horizontal scales, NOx mixing ratios were on average enhanced by 0.2–1.6 nmol mol−1. This enhancement was mainly attributed to NOx production by lightning and partly due to upward transport from the NOx-richer boundary layer. In addition, CO mixing ratios were occasionally enhanced, indicating upward transport from the boundary layer. For the first time, the composition of the anvil outflow from a large, long-lived mesoscale convective system (MCS advected from northern Argentina and Uruguay was investigated in more detail. Over a horizontal scale of about 400 km, NOx, CO and O3 mixing ratios were significantly enhanced in these air masses in the range of 0.6–1.1, 110–140 and 60–70 nmol mol−1, respectively. Analyses from trace gas correlations and a Lagrangian particle dispersion model indicate that polluted air masses, probably from the Buenos Aires urban area and from biomass burning regions, were uplifted by the MCS. Ozone was distinctly enhanced in the aged MCS outflow, due to photochemical production and entrainment of O3-rich air masses from the upper troposphere – lower stratosphere region. The aged MCS outflow was transported to the north, ascended and circulated, driven by the Bolivian High over the

  2. Lightning-produced NOx over Brazil during TROCCINOX: airborne measurements in tropical and subtropical thunderstorms and the importance of mesoscale convective systems

    Directory of Open Access Journals (Sweden)

    C. Schwierz

    2007-06-01

    Full Text Available During the TROCCINOX field experiments in February–March 2004 and February 2005, airborne in situ measurements of NO, NOy, CO, and O3 mixing ratios and the J(NO2 photolysis rate were carried out in the anvil outflow of thunderstorms over southern Brazil. Both tropical and subtropical thunderstorms were investigated, depending on the location of the South Atlantic convergence zone. Tropical air masses were discriminated from subtropical ones according to the higher equivalent potential temperature (Θe in the lower and mid troposphere, the higher CO mixing ratio in the mid troposphere, and the lower wind velocity in the upper troposphere within the Bolivian High (north of the subtropical jet stream. During thunderstorm anvil penetrations, typically at 20–40 km horizontal scales, NOx mixing ratios were distinctly enhanced and the absolute mixing ratios varied between 0.2–1.6 nmol mol−1 on average. This enhancement was mainly attributed to NOx production by lightning and partly due to upward transport from the NOx-richer boundary layer. In addition, CO mixing ratios were occasionally enhanced, indicating upward transport from the boundary layer. For the first time, the composition of the anvil outflow from a large, long-lived mesoscale convective system (MCS advected from northern Argentina and Uruguay was investigated in more detail. Over a horizontal scale of about 400 km, NOx, CO and O3 absolute mixing ratios were significantly enhanced in these air masses in the range of 0.6–1.1, 110–140 and 60–70 nmol mol−1, respectively. Analyses from trace gas correlations and a Lagrangian particle dispersion model indicate that polluted air masses, probably from the Buenos Aires urban area and from biomass burning regions, were uplifted by the MCS. Ozone was distinctly enhanced in the aged MCS outflow, due to photochemical production and entrainment of O3-rich air masses from the upper troposphere – lower stratosphere region. The aged MCS

  3. The physics of a thunderstorm

    Energy Technology Data Exchange (ETDEWEB)

    Mason, John [Department of Environmental Science and Technology, Imperial College London, Prince Consort Road, London SW7 2PE (United Kingdom); Mason, Nigel [Department of Physics and Astronomy, The Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom)

    2003-09-01

    The salient facts concerning the dynamical, physical and electrical properties of a thunderstorm, and of the detailed structure and associated electric field-changes of lightning flashes, are marshalled to deduce the criteria for a satisfactory quantitative theory of charge generation and separation leading to the growth of electric fields strong enough to initiate and to sustain lightning activity. A quantitative theory is presented of how charges are generated and separated when supercooled cloud droplets make grazing contact with the undersides of hail pellets (graupel) polarized initially by the Earth's fine-weather electric field. The rebounding droplets acquire a positive charge and are carried by the convective updraught towards the top of the cloud, while the hail pellets carrying a net negative charge fall towards cloud base. This creates a vertical dipole field which increases the polarizing charges on the hail pellets and so accelerates the rates of charge generation and separation, and so reinforces the vertical electrical field, which grows exponentially until insulation of the air breaks down and triggers a lightning flash. It is demonstrated that a thunderstorm cell, 2 km in diameter, producing small hail falling at 30 mm h{sup -1} can produce vertical electric fields of {approx}5000 V cm{sup -1} in about 10 min involving the separation of {approx}50 C of charge, enough to initiate a lightning flash which, on average, neutralizes about 20 C. As long as the hail persists, it continues to generate and separate sufficient charge to produce a succession of lightning flashes at about 30 s intervals. More frequent discharges at say 10 s intervals would require high rates of hail production in larger cells but are more likely to be produced by large multi-cellular storms sustained by strong convective currents for perhaps several hours.

  4. Positron clouds within thunderstorms

    CERN Document Server

    Dwyer, Joseph R; Hazelton, Bryna J; Grefenstette, Brian W; Kelley, Nicole A; Lowell, Alexander W; Schaal, Meagan M; Rassoul, Hamid K

    2015-01-01

    We report the observation of two isolated clouds of positrons inside an active thunderstorm. These observations were made by the Airborne Detector for Energetic Lightning Emissions (ADELE), an array of six gamma-ray detectors, which flew on a Gulfstream V jet aircraft through the top of an active thunderstorm in August 2009. ADELE recorded two 511 keV gamma-ray count rate enhancements, 35 seconds apart, each lasting approximately 0.2 seconds. The enhancements, which were about a factor of 12 above background, were both accompanied by electrical activity as measured by a flat-plate antenna on the underside of the aircraft. The energy spectra were consistent with a source mostly composed of positron annihilation gamma rays, with a prominent 511 keV line clearly visible in the data. Model fits to the data suggest that the aircraft was briefly immersed in clouds of positrons, more than a kilometer across. It is not clear how the positron clouds were created within the thunderstorm, but it is possible they were ca...

  5. Thermal characterization of nanoscale phononic crystals using supercell lattice dynamics

    Science.gov (United States)

    Davis, Bruce L.; Hussein, Mahmoud I.

    2011-12-01

    The concept of a phononic crystal can in principle be realized at the nanoscale whenever the conditions for coherent phonon transport exist. Under such conditions, the dispersion characteristics of both the constitutive material lattice (defined by a primitive cell) and the phononic crystal lattice (defined by a supercell) contribute to the value of the thermal conductivity. It is therefore necessary in this emerging class of phononic materials to treat the lattice dynamics at both periodicity levels. Here we demonstrate the utility of using supercell lattice dynamics to investigate the thermal transport behavior of three-dimensional nanoscale phononic crystals formed from silicon and cubic voids of vacuum. The periodicity of the voids follows a simple cubic arrangement with a lattice constant that is around an order of magnitude larger than that of the bulk crystalline silicon primitive cell. We consider an atomic-scale supercell which incorporates all the details of the silicon atomic locations and the void geometry. For this supercell, we compute the phonon band structure and subsequently predict the thermal conductivity following the Callaway-Holland model. Our findings dictate that for an analysis based on supercell lattice dynamics to be representative of the properties of the underlying lattice model, a minimum supercell size is needed along with a minimum wave vector sampling resolution. Below these minimum values, a thermal conductivity prediction of a bulk material based on a supercell will not adequately recover the value obtained based on a primitive cell. Furthermore, our results show that for the relatively small voids and void spacings we consider (where boundary scattering is dominant), dispersion at the phononic crystal unit cell level plays a noticeable role in determining the thermal conductivity.

  6. Thermal characterization of nanoscale phononic crystals using supercell lattice dynamics

    Directory of Open Access Journals (Sweden)

    Bruce L. Davis

    2011-12-01

    Full Text Available The concept of a phononic crystal can in principle be realized at the nanoscale whenever the conditions for coherent phonon transport exist. Under such conditions, the dispersion characteristics of both the constitutive material lattice (defined by a primitive cell and the phononic crystal lattice (defined by a supercell contribute to the value of the thermal conductivity. It is therefore necessary in this emerging class of phononic materials to treat the lattice dynamics at both periodicity levels. Here we demonstrate the utility of using supercell lattice dynamics to investigate the thermal transport behavior of three-dimensional nanoscale phononic crystals formed from silicon and cubic voids of vacuum. The periodicity of the voids follows a simple cubic arrangement with a lattice constant that is around an order of magnitude larger than that of the bulk crystalline silicon primitive cell. We consider an atomic-scale supercell which incorporates all the details of the silicon atomic locations and the void geometry. For this supercell, we compute the phonon band structure and subsequently predict the thermal conductivity following the Callaway-Holland model. Our findings dictate that for an analysis based on supercell lattice dynamics to be representative of the properties of the underlying lattice model, a minimum supercell size is needed along with a minimum wave vector sampling resolution. Below these minimum values, a thermal conductivity prediction of a bulk material based on a supercell will not adequately recover the value obtained based on a primitive cell. Furthermore, our results show that for the relatively small voids and void spacings we consider (where boundary scattering is dominant, dispersion at the phononic crystal unit cell level plays a noticeable role in determining the thermal conductivity.

  7. Automated effective band structures for defective and mismatched supercells

    Science.gov (United States)

    Brommer, Peter; Quigley, David

    2014-12-01

    In plane-wave density functional theory codes, defects and incommensurate structures are usually represented in supercells. However, interpretation of E versus k band structures is most effective within the primitive cell, where comparison to ideal structures and spectroscopy experiments are most natural. Popescu and Zunger recently described a method to derive effective band structures (EBS) from supercell calculations in the context of random alloys. In this paper, we present bs_sc2pc, an implementation of this method in the CASTEP code, which generates an EBS using the structural data of the supercell and the underlying primitive cell with symmetry considerations handled automatically. We demonstrate the functionality of our implementation in three test cases illustrating the efficacy of this scheme for capturing the effect of vacancies, substitutions and lattice mismatch on effective primitive cell band structures.

  8. The Impact of Mesoscale Environmental Uncertainty on the Prediction of a Tornadic Supercell Storm Using Ensemble Data Assimilation Approach

    Directory of Open Access Journals (Sweden)

    Nusrat Yussouf

    2013-01-01

    Full Text Available Numerical experiments over the past years indicate that incorporating environmental variability is crucial for successful very short-range convective-scale forecasts. To explore the impact of model physics on the creation of environmental variability and its uncertainty, combined mesoscale-convective scale data assimilation experiments are conducted for a tornadic supercell storm. Two 36-member WRF-ARW model-based mesoscale EAKF experiments are conducted to provide background environments using either fixed or multiple physics schemes across the ensemble members. Two 36-member convective-scale ensembles are initialized using background fields from either fixed physics or multiple physics mesoscale ensemble analyses. Radar observations from four operational WSR-88Ds are assimilated into convective-scale ensembles using ARPS model-based 3DVAR system and ensemble forecasts are launched. Results show that the ensemble with background fields from multiple physics ensemble provides more realistic forecasts of significant tornado parameter, dryline structure, and near surface variables than ensemble from fixed physics background fields. The probabilities of strong low-level updraft helicity from multiple physics ensemble correlate better with observed tornado and rotation tracks than probabilities from fixed physics ensemble. This suggests that incorporating physics diversity across the ensemble can be important to successful probabilistic convective-scale forecast of supercell thunderstorms, which is the main goal of NOAA’s Warn-on-Forecast initiative.

  9. Mesoscale modeling of the production and the three-dimensional transport of nitrogen oxides in thunderstorms; Mesoskalige Modellierung der Produktion und des dreidimensionalen Transports von Stickoxiden durch Gewitter

    Energy Technology Data Exchange (ETDEWEB)

    Fehr, T.

    2000-07-01

    Nitrogen oxides, NO{sub x} = NO + NO{sub 2}, play a fundamental role in tropospheric chemistry. Compared to other sources, the contribution of lightning induced NO{sub x} (LNO{sub x}) is known with considerable uncertainties and difficult to determine experimentally. The distribution of nitrogen oxides in an isolated thunderstorm is investigated using a modified version of the Penn State/NCAR Mesoscale Model (MM5) with cloud-scale resolution. A Lagrangian particle model has been developed to represent the NO{sub x} released by individual flashes. The position of the flash, the flash type, the geometrical properties of the channel, and the amount of emitted NO{sub x} are introduced to the MM5 in a parameterized form. On July 21, 1998, during the European lightning nitrogen oxides project (EULINOX) field campaign, a supercell development was observed in the German alpine foreland. Anvil penetrations by the DLR Falcon aircraft contributed high resolution profiles of NO{sub x}. DLR radar observation covered the complete life cycle of the thunderstorm. The lightning activity was recorded with a lightning positioning and tracking system (LPATS) run by local power suppliers, while radiosonde and aircraft measurements supplied detailed information on the atmospheric stratification ahead of the thunderstorm. This meteorological information was used to initalize a cloud-scale MM5 simulation. The modeled thunderstorm reproduces many observed properties, e.g. cell splitting, propagation speed and direction, anvil and overshooting top height, and WER (weak echo region). The number of simulated cloud-to-ground flashes, as well as the temporal evolution of the lightning activity are comparable to the LPAT observations. The general transport properties of the model thunderstorm are investigated using an inert PBL-tracer, as well as trajectory analysis. The simulated lightning activity leads to the release of approximately 1 000 000 NO{sub x}-particles. The thunderstorm produces 28

  10. Analysis and Forecast of a Tornadic Thunderstorm Using Multiple Doppler Radar Data, 3DVAR, and ARPS Model

    Directory of Open Access Journals (Sweden)

    Edward Natenberg

    2013-01-01

    Full Text Available A three-dimensional variational (3DVAR assimilation technique developed for a convective-scale NWP model—advanced regional prediction system (ARPS—is used to analyze the 8 May 2003, Moore/Midwest City, Oklahoma tornadic supercell thunderstorm. Previous studies on this case used only one or two radars that are very close to this storm. However, three other radars observed the upper-level part of the storm. Because these three radars are located far away from the targeted storm, they were overlooked by previous studies. High-frequency intermittent 3DVAR analyses are performed using the data from five radars that together provide a more complete picture of this storm. The analyses capture a well-defined mesocyclone in the midlevels and the wind circulation associated with a hook-shaped echo. The analyses produced through this technique are used as initial conditions for a 40-minute storm-scale forecast. The impact of multiple radars on a short-term NWP forecast is most evident when compared to forecasts using data from only one and two radars. The use of all radars provides the best forecast in which a strong low-level mesocyclone develops and tracks in close proximity to the actual tornado damage path.

  11. Thunderstorms, Andean Mountains Ridgeline, Argentina

    Science.gov (United States)

    1993-01-01

    In this scenic view of thunderstorms skirting the eastern ridgeline of the Andeas Mountains in northern Argentina (approximate coordinates 28.0S, 57.0W), the confluence of the Rio Salado and Rio Saladillo where they merge with the Rio Parana can be seen in sunglint. Thunderstorms along the eastern Andes are typical at this time of year (Southern Hemisphere summer) with anvils moving to the east from the core of the storm.

  12. Global thunderstorm activity research survey

    Science.gov (United States)

    Coroniti, S. C.

    1982-01-01

    The published literature on the subject of the monitoring of global thunderstorm activity by instrumented satellites was reviewed. A survey of the properties of selected physical parameters of the thunderstorm is presented. The concepts used by satellites to identify and to measure terrestrial lightning pulses are described. The experimental data acquired by satellites are discussed. The scientific achievements of the satellites are evaluated against the needs of scientists and the potential requirements of user agencies. The performances of the satellites are rated according to their scientific and operational achievements.

  13. Gamma-rays Associated with Nearby Thunderstorms at Ground Level

    CERN Document Server

    Ringuette, Rebecca; Granger, Douglas; Guzik, T Gregory; Stewart, Michael; Wefel, John P

    2014-01-01

    The TGF and Energetic Thunderstorm Rooftop Array (TETRA) is an array of NaI scintillators located at rooftop level on the campus of Louisiana State University in Baton Rouge, Louisiana. From July 2010 through March 2014, TETRA has detected 28 millisecond-duration bursts of gamma-rays at energies 50 keV - 2 MeV associated with nearby (< 8 km) thunderstorms. The ability to observe ground-level Terrestrial Gamma Flashes from close to the source allows a unique analysis of the storm cells producing these events. The results of the initial analysis will be presented.

  14. Possible role of aerosols in the charge structure of isolated thunderstorms

    Science.gov (United States)

    Pawar, S. D.; Gopalakrishnan, V.; Murugavel, P.; Veremey, N. E.; Sinkevich, A. A.

    2017-01-01

    The electric field and Maxwell current density measured below 32 small isolated thunderstorms over Pune (India) have been analyzed here. These data clearly show the presence of 10 out of 32 thunderstorms with inverted polarity charge structure. Values of Aerosol Optical Depth (AOD) on thunderstorm days taken from MODIS show that all the thunderstorms with inverted polarity occurred on days with significantly higher AOD compared to normal polarity thunderstorms. The peak flash rate did not show significant difference between normal polarity thunderstorms and inverted polarity thunderstorms. The dew point depression (DPD) during pre-monsoon thunderstorms shows good correlation with inverted polarity charge structure. Observations suggest that aerosol concentration plays an important role in the formation of inverted polarity charge structure in these thunderclouds. In presence of high aerosol concentration with adequate ice nuclei non-inductive charging mechanism can produce strong and wide spread positive charge region in the lower portion of cloud. However, observed good correlation of DPD with inverted polarity charge structure in the pre-monsoon period suggest that the effect of high cloud base height on inverted polarity charge structure as suggested by Williams et al. (2005) cannot be ruled out.

  15. Modelling Discharge Inception in Thunderstorms

    NARCIS (Netherlands)

    Rutjes, Casper; Dubinova, Anna; Ebert, Ute; Buitink, Stijn; Scholten, Olaf; Trinh, Gia Thi Ngoc

    2015-01-01

    The electric fields in thunderstorms can exceed the breakdown value locally near hydrometeors. But are fields high enough and the regions large enough to initiate a streamer discharge? And where would a sufficient density of free electrons come from to start the discharge in the humid air that rapid

  16. Use of Dual-Polarization Radar Variables to Assess Low-Level Wind Shear in Severe Thunderstorm Near-storm Environments in the Tennessee Valley

    Science.gov (United States)

    Crowe, Christina C.; Schultz, Christopher J.; Kumjian, Matthew; Carey, Lawerence D.; Petersen, Walter A.

    2011-01-01

    The upgrade of the National Weather Service (NWS) network of S ]band dual-polarization radars is currently underway, and the incorporation of polarimetric information into the real ]time forecasting process will enhance the forecaster fs ability to assess thunderstorms and their near ]storm environments. Recent research has suggested that the combination of polarimetric variables differential reflectivity (ZDR) and specific differential phase (KDP) can be useful in the assessment of low level wind shear within a thunderstorm. In an environment with strong low ]level veering of the wind, ZDR values will be largest along the right inflow edge of the thunderstorm near a large gradient in horizontal reflectivity (indicative of large raindrops falling with a relative lack of smaller drops), and take the shape of an arc. Meanwhile, KDP values, which are proportional to liquid water content and indicative of a large number of smaller drops, are maximized deeper into the forward flank precipitation shield than the ZDR arc as the smaller drops are being advected further from the updraft core by the low level winds than the larger raindrops. Using findings from previous work, three severe weather events that occurred in North Alabama were examined in order to assess the utility of these signatures in determining the potential for tornadic activity. The first case is from October 26, 2010, where a large number of storms indicated tornadic potential from a standard reflectivity and velocity analysis but very few storms actually produced tornadoes. The second event is from February 28, 2011, where tornadic storms were present early on in the event, but as the day progressed, the tornado threat transitioned to a high wind threat. The third case is from April 27, 2011, where multiple rounds of tornadic storms ransacked the Tennessee Valley. This event provides a dataset including multiple modes of tornadic development, including QLCS and supercell structures. The overarching goal

  17. The atmospheric electric global circuit. [thunderstorm activity

    Science.gov (United States)

    Kasemir, H. W.

    1979-01-01

    The hypothesis that world thunderstorm activity represents the generator for the atmospheric electric current flow in the earth atmosphere between ground and the ionosphere is based on a close correlation between the magnitude and the diurnal variation of the supply current (thunderstorm generator current) and the load current (fair weather air-earth current density integrated over the earth surface). The advantages of using lightning survey satellites to furnish a base for accepting or rejecting the thunderstorm generator hypothesis are discussed.

  18. Amplified radio emission from cosmic ray air showers in thunderstorms

    CERN Document Server

    Buitink, S; Asch, T; Badea, F; Bähren, L; Bekk, K; Bercuci, A; Bertaina, M; Biermann, P L; Blumer, J; Bozdog, H; Brancus, I M; Bruggemann, M; Buchholz, P; Butcher, H; Chiavassa, A; Cossavella, F; Daumiller, K; Di Pierro, F; Doll, P; Engel, R; Falcke, H; Gemmeke, H; Ghia, P L; Glasstetter, R; Grupen, C; Haungs, A; Heck, D; Hörandel, J R; Horneffer, A; Huege, T; Kampert, K H; Kolotaev, Y; Krömer, O; Kuijpers, J; Lafebre, S; Mathes, H J; Mayer, H J; Meurer, C; Milke, J; Mitrica, B; Morello, C; Navarra, G; Nehls, S; Nigl, A; Obenland, R; Oehlschläger, J; Ostapchenko, S; Over, S; Petcu, M; Petrovic, J; Pierog, T; Plewnia, S; Rebel, H; Risse, A; Roth, M; Schieler, H; Sima, O; Singh, K; Stumpert, M; Toma, G; Trinchero, G C; Ulrich, H; Van Buren, J; Walkowiak, W; Weindl, A; Wochele, J; Zabierowski, J; Zensus, J A; Zimmermann, D; Buitink, Stijn

    2007-01-01

    Cosmic ray air showers produce radio emission, consisting in large part of geosynchrotron emission. Since the radiation mechanism is based on particle acceleration, the atmospheric electric field can play an important role. Especially inside thunderclouds large electric fields can be present. We examine the contribution of an electric field to the emission mechanism theoretically and experimentally. Two mechanisms of amplification of radio emission are considered: the acceleration radiation of the shower particles and the radiation from the current that is produced by ionization electrons moving in the electric field. We selected and evaluated LOPES data recorded during thunderstorms, periods of heavy cloudiness and periods of cloudless weather. We find that during thunderstorms the radio emission can be strongly enhanced. No amplified pulses were found during periods of cloudless sky or heavy cloudiness, suggesting that the electric field effect for radio air shower measurements can be safely ignored during ...

  19. Analysis on Three-dimensional Structure and Echo Characteristic Quantity of a Supercell Storm

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    [Objective] The research aimed to study three-dimensional structure and echo characteristic quantity of a supercell storm in central Gansu on May 30,2005.[Method] By monitoring data of Lanzhou CINRAD/CC Doppler radar,the three-dimensional structure characteristics of a rare supercell storm which happened in central Gansu on May 30,2005 were analyzed.We tried to reveal three-dimensional structure and echo characteristic index of supercell storm in the northeast of Qinghai-Tibet Plateau,and find reason of rar...

  20. THUNDERSTORMS-RISK FACTORS IN AVIATION. CASE STUDY: AREA OF RESPONSABILITY OF THE BUCHAREST-OTOPENI AERODROME ON 30.06.2009

    OpenAIRE

    2015-01-01

    Thunderstorms are always dangerous weather phenomena for flight safety and, irrespective of their nature, they have a negative impact on all aviation activities. Thunderstorm clouds can generate severe and rapid changes of various meteorological elements (visibility, cloudiness and cloud lower base, wind), sometimes to such a great extent that landing may become impossible. Thunderstorms are serious weather hazards in aviation and may produce great damage and even casualties. One such unfortu...

  1. LES of Langmuir supercells under constant crosswind tidal forcing

    Science.gov (United States)

    Walker, Rachel; Zhang, Jie; Juha, Mario; Gosch, Chester; Tejada-Martinez, Andres

    2015-11-01

    We report on the impact of a crosswind tidal current on Langmuir supercells (LSCs) in shallow water computed via LES. LSCs consist of parallel counter rotating vortices engulfing the water column in unstratified conditions. These cells have been observed in shallow continental shelf regions of ~15 meters depth during the passage of storms. The cells are aligned roughly in the wind direction and are generated by the interaction of the wind-driven shear current with the Stokes drift velocity induced by surface gravity waves. Without tides, LES reveals that the typical crosswind width of a LSC is ~4 times the water column depth (H). Under a relatively weak crosswind tidal current (weaker than the downwind current), the constant crosswind tidal forcing applied causes a merging of cells leading to cells of width ~8H. The opposite occurs under a crosswind tidal current stronger than the downwind current as the constant crosswind tidal force is able to break up the LSCs giving rise to smaller scale cells with different turbulent structure than that associated with LSC. Statistics of the turbulence during strong and weak crosswind tides will be contrasted and implications of an oscillating crosswind tidal force will be discussed. Support from the US National Science Foundation and the Gulf of Mexico Research Initiative is gratefully acknowledged.

  2. Injection of lightning-produced NOx, water vapor, wildfire emissions, and stratospheric air to the UT/LS as observed from DC3 measurements

    Science.gov (United States)

    Huntrieser, H.; Lichtenstern, M.; Scheibe, M.; Aufmhoff, H.; Schlager, H.; Pucik, T.; Minikin, A.; Weinzierl, B.; Heimerl, K.; Pollack, I. B.; Peischl, J.; Ryerson, T. B.; Weinheimer, A. J.; Honomichl, S.; Ridley, B. A.; Biggerstaff, M. I.; Betten, D. P.; Hair, J. W.; Butler, C. F.; Schwartz, M. J.; Barth, M. C.

    2016-06-01

    During the Deep Convective Clouds and Chemistry (DC3) experiment in summer 2012, airborne measurements were performed in the anvil inflow/outflow of thunderstorms over the Central U.S. by three research aircraft. A general overview of Deutsches Zentrum für Luft- und Raumfahrt (DLR)-Falcon in situ measurements (CO, O3, SO2, CH4, NO, NOx, and black carbon) is presented. In addition, a joint flight on 29 May 2012 in a convective line of isolated supercell storms over Oklahoma is described based on Falcon, National Science Foundation/National Center for Atmospheric Research Gulfstream-V (NSF/NCAR-GV), and NASA-DC8 trace species in situ and lidar measurements. During DC3 some of the largest and most destructive wildfires in New Mexico and Colorado state's history were burning, which strongly influenced air quality in the DC3 thunderstorm inflow and outflow region. Lofted biomass burning (BB) plumes were frequently observed in the mid- and upper troposphere (UT) in the vicinity of deep convection. The impact of lightning-produced NOx (LNOx) and BB emissions was analyzed on the basis of mean vertical profiles and tracer-tracer correlations (CO-NOx and O3-NO). On a regular basis DC3 thunderstorms penetrated the tropopause and injected large amounts of LNOx into the lower stratosphere (LS). Inside convection, low O3 air (~80 nmol mol-1) from the lower troposphere was rapidly transported to the UT/LS region. Simultaneously, O3-rich stratospheric air masses (~100-200 nmol mol-1) were present around and below the thunderstorm outflow and enhanced UT-O3 mixing ratios significantly. A 10 year global climatology of H2O data from the Aura Microwave Limb Sounder confirmed that the Central U.S. is a preferred region for convective injection into the LS.

  3. Electric field soundings through thunderstorms

    Science.gov (United States)

    Marshall, Thomas C.; Rust, W. D.

    1991-01-01

    Twelve balloon soundings of the electric field in thunderstorms are reported. The maximum magnitude of E in the storms averaged 96 +/-28 kV/m, with the largest being 146 kV/m. The maximum was usually observed between vertically adjacent regions of opposite charge. Using a 1D approximation to Gauss' law, four to ten charge regions in the storms are inferred. The magnitude of the density in the charge regions varied between 0.2 and 13 nC/cu m. The vertical extent of the charge regions ranged from 130 to 2100 m. None of the present 12 storms had charge distributions that fit the long-accepted model of Simpson et al. (1937, 1941) of a lower positive charge, a main negative charge, and an upper positive charge. In addition to regions similar to the Simpson model, the present storms had screening layers at the upper and lower cloud boundaries and extra charge regions, usually in the lower part of the cloud.

  4. Prediction of severe thunderstorms over Sriharikota Island by using the WRF-ARW operational model

    Science.gov (United States)

    Papa Rao, G.; Rajasekhar, M.; Pushpa Saroja, R.; Sreeshna, T.; Rajeevan, M.; Ramakrishna, S. S. V. S.

    2016-05-01

    Operational short range prediction of Meso-scale thunderstorms for Sriharikota(13.7°N ,80.18°E) has been performed using two nested domains 27 & 9Km configuration of Weather Research & Forecasting-Advanced Research Weather Model (WRF- ARW V3.4).Thunderstorm is a Mesoscale system with spatial scale of few kilometers to a couple of 100 kilometers and time scale of less than an one hour to several hours, which produces heavy rain, lightning, thunder, surface wind squalls and down-bursts. Numerical study of Thunderstorms at Sriharikota and its neighborhood have been discussed with its antecedent thermodynamic stability indices and Parameters that are usually favorable for the development of convective instability based on WRF ARW model predictions. Instability is a prerequisite for the occurrence of severe weather, the greater the instability, the greater will be the potential of thunderstorm. In the present study, K Index, Total totals Index (TTI), Convective Available Potential Energy (CAPE), Convective Inhibition Energy (CINE), Lifted Index (LI), Precipitable Water (PW), etc. are the instability indices used for the short range prediction of thunderstorms. In this study we have made an attempt to estimate the skill of WRF ARW predictability and diagnosed three thunderstorms that occurred during the late evening to late night of 31st July, 20th September and 2nd October of 2015 over Sriharikota Island which are validated with Local Electric Field Mill (EFM), rainfall observations and Chennai Doppler Weather Radar products. The model predicted thermodynamic indices (CAPE, CINE, K Index, LI, TTI and PW) over Sriharikota which act as good indicators for severe thunderstorm activity.

  5. Local lattice relaxations in random metallic alloys: Effective tetrahedron model and supercell approach

    DEFF Research Database (Denmark)

    Ruban, Andrei; Simak, S.I.; Shallcross, S.;

    2003-01-01

    We present a simple effective tetrahedron model for local lattice relaxation effects in random metallic alloys on simple primitive lattices. A comparison with direct ab initio calculations for supercells representing random Ni0.50Pt0.50 and Cu0.25Au0.75 alloys as well as the dilute limit of Au...

  6. Thunderstorms and Flooding of August 17, 2007, with a Context Provided by a History of Other Large Storm and Flood Events in the Black Hills Area of South Dakota

    Science.gov (United States)

    Driscoll, Daniel G.; Bunkers, Matthew J.; Carter, Janet M.; Stamm, John F.; Williamson, Joyce E.

    2010-01-01

    flow of 26,000 cubic feet per second was generated entirely within an intervening drainage area of only 44.4 square miles. An especially large flow of 44,100 cubic feet per second was documented for this location in 1972. The 2007 peak flow of 18,600 cubic feet per second for Battle Creek at Hermosa (station 06406000) was only slightly smaller than the 1972 peak flow of 21,400 cubic feet per second. Peak-flow values from 2007 for three sites with small drainage areas (less than 1.0 square mile) plot close to a regional envelope curve, indicating exceptionally large flow values, relative to drainage area. Physiographic factors that affect flooding in the area were examined. The limestone headwater hydrogeologic setting (within and near the Limestone Plateau area on the western flank of the Black Hills) has distinctively suppressed peak-flow characteristics for small recurrence intervals. Uncertainty is large, however, regarding characteristics for large recurrence intervals (low-probability floods) because of a dearth of information regarding the potential for generation of exceptionally strong rain-producing thunderstorms. In contrast, the greatest potential for exceptionally damaging floods is around the flanks of the rest of the Black Hills area because of steep topography and limited potential for attenuation of flood peaks in narrow canyons. Climatological factors that affect area flooding also were examined. Area thunderstorms are largely terrain-driven, especially with respect to their requisite upward motion, which can be initiated by orographic lifting effects, thermally enhanced circulations, and obstacle effects. Several other meteorological processes are influential in the development of especially heavy precipitation for the area, including storm cell training, storm anchoring or regeneration, storm mergers, supercell development, and weak upper-level air flow. A composite of storm total precipitation amounts for 13 recent individual storm events indicates

  7. Progress of research to identify rotating thunderstorms using satellite imagery

    Science.gov (United States)

    Anderson, Charles E.

    1988-01-01

    The possibility of detecting potentially tornadic thunderstorm cells from geosynchronous satelite imagery is determined. During the life of the contract, we examined eight tornado outbreak cases which had a total of 124 individual thunderstorm cells, 37 of which were tornadic.These 37 cells produced a total of 119 tornadoes. The outflow characteristics of all the cells were measured. Through the use of a 2-D flow field model, we were able to simulate the downstream developmemt of an anvil cloud plume which was emitted by the storm updraft at or near the tropopause. We used two parameters to characterize the anvil plume behavior: its speed of downstream propagation (U max) and the clockwise deviation of the centerline of the anvil plume from the storm relative ambient wind at the anvil plume outflow level (MDA). U max was the maximum U-component of the anvil wind parameter required to successfully maintain an envelope of translating particles at the tip of the expanding anvil cloud. MDA was the measured deviation angle acquired from McIDAS, between the storm relative ambient wind direction and the storm relative anvil plume outflow direction; tha latter being manipulated by controlling a tangential wind component to force the envelope of particles to maintain their position of surrounding the expanding outflow cloud.

  8. First observations of Gigantic Jets from Monsoon Thunderstorms over India

    Science.gov (United States)

    Singh, Rajesh; Maurya, Ajeet; Chanrion, Olivier; Neubert, Torsten; Cummer, Steven; Mlynarczyk, Janusz; Bór, József; Siingh, Devendraa; Cohen, Morris; Kumar, Sushil

    2016-04-01

    Gigantic Jets are electric discharges from thunderstorm cloud tops to the bottom of the ionosphere at ~80 km altitude. After their first discovery in 2001, relatively few observations have been reported. Most of these are from satellites at large distances and a few tens from the ground at higher spatial resolution. Here we report the first Gigantic Jets observed in India from two thunderstorm systems that developed over the land surface from monsoon activity, each storm producing two Gigantic Jets. The jets were recorded by a video camera system at standard video rate (20 ms exposure) at a few hundred km distance. ELF measurements suggest that the jets are of the usual negative polarity and that they develop in less than 40 ms, which is faster than most jets reported in the past. The jets originate from the leading edge of a slowly drifting convective cloud complex close to the highest regions of the clouds and carry ~25 Coulomb of charge to the ionosphere. One jet has a markedly horizontal displacement that we suggest is caused by a combination of close-range cloud electric fields at inception, and longer-range cloud fields at larger distances during full development. The Gigantic Jets are amongst the few that have been observed over land.

  9. Runaway breakdown and electrical discharges in thunderstorms

    Science.gov (United States)

    Milikh, Gennady; Roussel-Dupré, Robert

    2010-12-01

    This review considers the precise role played by runaway breakdown (RB) in the initiation and development of lightning discharges. RB remains a fundamental research topic under intense investigation. The question of how lightning is initiated and subsequently evolves in the thunderstorm environment rests in part on a fundamental understanding of RB and cosmic rays and the potential coupling to thermal runaway (as a seed to RB) and conventional breakdown (as a source of thermal runaways). In this paper, we describe the basic mechanism of RB and the conditions required to initiate an observable avalanche. Feedback processes that fundamentally enhance RB are discussed, as are both conventional breakdown and thermal runaway. Observations that provide clear evidence for the presence of energetic particles in thunderstorms/lightning include γ-ray and X-ray flux intensifications over thunderstorms, γ-ray and X-ray bursts in conjunction with stepped leaders, terrestrial γ-ray flashes, and neutron production by lightning. Intense radio impulses termed narrow bipolar pulses (or NBPs) provide indirect evidence for RB particularly when measured in association with cosmic ray showers. Our present understanding of these phenomena and their enduring enigmatic character are touched upon briefly.

  10. Structure of Thunderstorm Gust Fronts with Topographic Effects

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Surface meteorological observations, associated with gust fronts produced by thunderstorm outflows over Tehran, an area surrounded by mountains, have been analyzed. Distinctive features are sudden drop in air temperature, up to 10℃, sharp increase in wind speed, up to 30 m s-1, with wind shift, to northwesterly, ressure jump, up to 4 hPa, humidity increase, up to 40%, and rain after some 20 min. Gust fronts which often occur in spring time, have a typical thickness of about 1.5 km and produce vertical wind shear of the order of 10-2s-1. Although these features seem to be common for most of the events, their intensities differ from one event to another, indicating that the gust fronts may occur in different sizes and shapes. Apart from a dominant effect on the formation of the original thunderstorms, topography appears to break up the frontal structure of the gust fronts. The internal Rossby radius of deformation for these flows is small enough (~ 100 km) for rotational effects to be minor.A laboratory model of the gust front (gravity current) also shows that it initially has a distinctive head with a turbulent wake, and can be broken up by topography. It is shown that when the environment is stratified, turbulence due to lobes and clefts instabilities near the nose of the current is suppressed. When the ground is rough, these instabilities are highly amplified and the internal Froude number of the flow is reduced. The bottom slope in the presence of rough topography leads to the break up of the current head and produces a broad and highly non-uniform head, recognized in the density signals.

  11. Lattice dynamics and electron-phonon coupling calculations using nondiagonal supercells

    Science.gov (United States)

    Lloyd-Williams, Jonathan; Monserrat, Bartomeu

    Quantities derived from electron-phonon coupling matrix elements require a fine sampling of the vibrational Brillouin zone. Converged results are typically not obtainable using the direct method, in which a perturbation is frozen into the system and the total energy derivatives are calculated using a finite difference approach, because the size of simulation cell needed is prohibitively large. We show that it is possible to determine the response of a periodic system to a perturbation characterized by a wave vector with reduced fractional coordinates (m1 /n1 ,m2 /n2 ,m3 /n3) using a supercell containing a number of primitive cells equal to the least common multiple of n1, n2, and n3. This is accomplished by utilizing supercell matrices containing nonzero off-diagonal elements. We present the results of electron-phonon coupling calculations using the direct method to sample the vibrational Brillouin zone with grids of unprecedented size for a range of systems, including the canonical example of diamond. We also demonstrate that the use of nondiagonal supercells reduces by over an order of magnitude the computational cost of obtaining converged vibrational densities of states and phonon dispersion curves. J.L.-W. is supported by the Engineering and Physical Sciences Research Council (EPSRC). B.M. is supported by Robinson College, Cambridge, and the Cambridge Philosophical Society. This work was supported by EPSRC Grants EP/J017639/1 and EP/K013564/1.

  12. Downbursts and microbursts - An aviation hazard. [downdrafts beneath thunderstorms

    Science.gov (United States)

    Fujita, T. T.

    1980-01-01

    Downburst and microburst phenomena occurring since 1975 are studied, based on meteorological analyses of aircraft accidents, aerial surveys of wind effects left behind downbursts, and studies of sub-mesoscale wind systems. It is concluded that microbursts beneath small, air mass thunderstorms are unpredictable in terms of weather forecast. Most aircraft incidents, however, were found to have occurred in the summer months, June through August. An intense microburst could produce 150 mph horizontal winds as well as 60 fps downflows at the tree-top level. The largest contributing factor to aircraft difficulties seemed to be a combination of the headwind decrease and the downflow. Anemometers and/or pressure sensors placed near runways were found effective for detecting gust fronts, but not for detecting downbursts. It is recommended that new detection systems placed on the ground or airborne, be developed, and that pilots be trained for simulated landing and go-around through microbursts.

  13. Microphysical effects of Saharan dusts on an orogenic thunderstorm

    Directory of Open Access Journals (Sweden)

    T. Hashino

    2008-06-01

    Full Text Available This study investigates the microphysical sensitivity of an orogenic thunderstorm during Genoa 1992 flood event to the concentration and solubility of nucleating aerosols. Idealized 2-D simulations with a new microphysical scheme and a cloud resolving model showed the solubility of CCN can be as important as their concentration. High solubility cases of CCN led to less accumulation of precipitation on the ground and more fraction of the accumulation produced by heavy precipitation than lower solubility cases. The response of vertical motion to the solubility was different for cases with and without dust layer. The preliminary results show that the ice nucleation processes affected by solubility and dust layer may be detected by remote sensing technology.

  14. Supercell design for first-principles simulations of solids and application to diamond, silica, and superionic water

    Science.gov (United States)

    Militzer, B.

    2016-12-01

    For efficient first-principles computation of crystalline materials at high density and temperature, an optimal choice of the supercell is important to minimize finite size errors. An algorithm is presented to construct compact supercells for arbitrary crystal structures. Rather than constructing standard supercells by replicating the conventional unit cell, we employ the full flexibility that we gain by using arbitrary combinations of the primitive cell vectors in order to construct a series of cubic and nearly cubic supercells. In cases where different polymorphs of a material needed to be compared, we are able construct supercells of consistent size. Our approach also allows us to efficiently study the finite size effects in systems like superionic water where they would otherwise difficult to obtain because a standard replication of the unit cells leads to supercells that are too expensive to be used for first-principles simulations. We apply our method to simple, body-centered, and face-centered cubic as well as hexagonal close packed cells. We present simulation results for diamond, silica in the pyrite structure, and superionic water with an face-centered cubic oxygen sub-lattice. The effects of the finite simulation cell size and Brillouin zone sampling on the computed pressure and internal energy are analyzed.

  15. Schumann Resonance spectra decomposition method and studies of the locations of the African thunderstorm centres

    Science.gov (United States)

    Dyrda, Michal; Kulak, Andrzej; Mlynarczyk, Janusz; Ostrowski, Michal; Kubisz, Jerzy; Michalec, Adam; Nieckarz, Zenon

    2014-05-01

    The idea, that the global atmospheric electric circuit is driven by global lightning activity was introduced at the beginning of the last century. Today, the different observational methods are used from satellites to the radio observations performed in the extremely low frequency (ELF) range to evaluate local as well as global lightning activity, its spatial and temporal variability and influence on our planet and Earth's climate. The ground-based thunderstorms observations, particularly ELF, also allow the measurements of the dipole moment of discharges. Global lightning activity excites the Earth-ionosphere cavity and the produced electromagnetic radiation is responsible for generating the Schumann resonance (SR). The interaction of the standing and travelling waves leads to asymmetric shape of the observational SR power spectra picks, which was noticed by Kułak et al. (2006). They proposed a spectral decomposition method, what allows to separate the resonant field from the travelling wave contribution, which can be dominant at small distances from the sources. In such approach, one can apply the inverse problem solution for determining a distance of the dominant signal source. The distances to the thunderstorm centres are calculated using the numerical as well as the analytical models for the electromagnetic waves propagation in the Earth-ionosphere cavity. The ELF electromagnetic waves, recorded by Hylaty ELF station, located in South-East of Poland are used to derive the distances to the most powerful thunderstorm centres located in Africa and hence to obtain 1-D thunderstorm lightning activity maps. The observational data taken in January and August 2011 were binned in 10 minute intervals and SR power spectra were derived. Then a curve describing seven asymmetric SR maxima was fitted to the spectrum for each time interval. We use chi-squared test to compare the resulted decomposed power spectra with curves obtained within the considered numerical and

  16. Relationships between cloud-to-ground flashes and hydrometeors in a thunderstorm in Fujian province

    Science.gov (United States)

    Zhang, Tinglong; Zhao, Guo; Wei, Changxiong; Gao, Yi; Yu, Hai; Zhou, Fangcong

    2017-02-01

    A local severe thunderstorm, occurring near the coastal region in Fujian province, China, was chosen to study the relationships between hydrometeors and cloud-to-ground (CG) flash activities. This thunderstorm case study was carried out by using vehicle-mounted X-band dual-polarization radar on August 28, 2009. On the basis of polarimetric parameters, the hydrometeors were identified by fuzzy logic hydrometeor classification (FLHC). The results show that the thunderstorm grew into a squall line with a maximum flash rate of 85 fl/5 min in mature stage. Negative CG constituted approximately 97.3% of total CG flashes. More than 90% of the CG flashes occurred in the convective regions, and less than 10% occurred in the stratiform region. The strong echo volume in convective region had a positive linear correlation with the CG flashes rate. Seven types of hydrometeors, namely, rain (RN), aggregates (AG), low-density graupel (LDG), high-density graupel (HDG), vertically aligned ice crystals (VI), drizzle-light rain (DR), and ice crystals (IC), have been classified; the first five of the hydrometeors are predominant in the thunderstorm. RN is located mainly in regions warmer than 0 °C; the HDG is located in the middle and lower regions colder than 0 °C; and LDG and VI mainly appear in the upper portion of the thunderstorm. The ice hydrometeors seemly had a close relation with CG flashes because the total CG flash rates had a strong positive correlation with the grid number of AG, LDG, HDG, and VI in the convective region. However, the sufficient ice hydrometeors did not produce frequent CG flashes in the stratiform region. It suggests that the dynamic structure is also very important for triggering lightning flashes.

  17. Rapid vertical trace gas transport by an isolated midlatitude thunderstorm

    Science.gov (United States)

    Hauf, Thomas; Schulte, Peter; Alheit, Reiner; Schlager, Hans

    1995-11-01

    During the cloud dynamics and chemistry field experiment CLEOPATRA in the summer of 1992 in southern Germany, the Deutsche Forschungsanstalt für Luft- und Raumfahrt (DLR) (German Aerospace Research Establishment) research aircraft Falcon traversed four times the anvil of a severe, isolated thunderstorm. The first two traverses were at 8 km altitude and close to the anvil cloud base, while the second two traverses were at 10 km. During the 8-km traverse, measured ozone mixing ratios dropped by 13 parts per billion by volume (ppbv) from the ambient cloud free environment to the anvil cloud, while water vapor increased by 0.3 g kg-1. At the 10-km traverses, ozone dropped by 25 ppbv, while water vapor increased by 0.18 g kg-1. Three-dimensional numerical thunderstorm simulations were performed to understand the cause of these changes. The simulations included the transport of two chemical inert tracers. Ozone was assumed to be one of them. The initial ozone profile was composed from an ozone routine sounding and the in situ Falcon measurements prior to the thunderstorm development. The second tracer is typical for a surface released pollutant with a nonzero, constant value in the boundary layer but zero above it. The redistribution of both tracers by the storm is calculated and compared with the observations. For the anvil penetration at 10 km, the calculated difference in ozone mixing ratios is 21 ppbv, while for water vapor an increase of 0.25 g kg-1 was found, in good agreement with the observations. To validate the model results, the radar reflectivity was calculated from simulated fields of cloud water, rain, graupel, hail, and snow and ice crystals and compared with observed values. With respect to maximum reflectivity values and spatial scales, again, excellent agreement was achieved. It is concluded that the rapid transport from the boundary layer directly into the anvil level is the most likely cause of the observed ozone decrease and water vapor increase

  18. Remote detection and diagnosis of thunderstorm turbulence

    Science.gov (United States)

    Williams, John K.; Sharman, Robert; Craig, Jason; Blackburn, Gary

    2008-08-01

    This paper describes how operational radar, satellite and lightning data may be used in conjunction with numerical weather model data to provide remote detection and diagnosis of atmospheric turbulence in and around thunderstorms. In-cloud turbulence is measured with the NEXRAD Turbulence Detection Algorithm (NTDA) using extensively qualitycontrolled, ground-based Doppler radar data. A real-time demonstration of the NTDA includes generation of a 3-D turbulence mosaic covering the CONUS east of the Rocky Mountains, a web-based display, and experimental uplinks of turbulence maps to en-route commercial aircraft. Near-cloud turbulence is inferred from thunderstorm morphology, intensity, growth rate and environment data provided by (1) satellite radiance measurements, rates of change, winds, and other derived features, (2) lightning strike measurements, (3) radar reflectivity measurements and (4) weather model data. These are combined via a machine learning technique trained using a database of in situ turbulence measurements from commercial aircraft to create a predictive model. This new capability is being developed under FAA and NASA funding to enhance current U.S. and international turbulence decision support systems, allowing rapid-update, highresolution, comprehensive assessments of atmospheric turbulence hazards for use by pilots, dispatchers, and air traffic controllers. It will also contribute to the comprehensive 4-D weather information database for NextGen.

  19. A review of severe thunderstorms in Australia

    Science.gov (United States)

    Allen, John T.; Allen, Edwina R.

    2016-09-01

    Severe thunderstorms are a common occurrence in Australia and have been documented since the first European settlement in 1788. These events are characterized by large damaging hail in excess of 2 cm, convective wind gusts greater than 90 km h- 1 and tornadoes, and contribute a quarter of all natural hazard-related losses in the country. This impact has lead to a growing body of research and insight into these events. In this article, the state of knowledge regarding their incidence, distribution, and the resulting hail, tornado, convective wind, and lightning risk will be reviewed. Applying this assessment of knowledge, the implications for forecasting, the warning process, and how these events may respond to climate change and variability will also be discussed. Based on this review, ongoing work in the field is outlined, and several potential avenues for future research and exploration are suggested. Most notably, the need for improved observational or proxy climatologies, the forecasting guidelines for tornadoes, and the need for a greater understanding of how severe thunderstorms respond to climate variability are highlighted.

  20. Phonon dispersion relations of Sb2S3 and Bi2S3 using the supercell force-constant method

    Science.gov (United States)

    Gan, Chee Kwan; Chua, Kun Ting Eddie; Liu, Yun

    2015-03-01

    We present a lattice dynamical study on the orthorhombic antimony sulphide (Sb2S3) and bismuth sulphide (Bi2S3) using the supercell force-constant method. We find that the slow decay of the interatomic force constants for these compounds in the Pnma setting critically demand the use of a large supercell of 2 × 4 × 2 that consists of 320 atoms. To enable a practical calculation the space group information is fully utilized where only inequivalent atoms within the primitive cell are displaced for the force calculations. The effect of Born effective charges is incorporated into the method. We compare our results with that obtained from the density-functional perturbation theory. We found that smaller supercells could lead to unphysical acoustic phonon softening and lifting of the degeneracies along high symmetry directions. Our results provide a proper guideline for the use of the supercell force-constant method: the supercell size must be carefully be tested along with other parameters such as the kinetic energy cutoff, the Brillouin zone sampling or the self-consistent convergence criteria.

  1. Synoptic patterns associated with thunderstorms in Poland

    Energy Technology Data Exchange (ETDEWEB)

    Kolendowicz, Leszek [Adam Mickiewicz Univ., Poznan (Poland). Inst. of Physical Geography and Environmental Planning

    2012-04-15

    The purpose of this study is an analysis of the impact of synoptic patterns over the landmass of Europe with specific reference to the frequency of the occurrence of thunderstorms in Poland during the period 1971-2008. The subjective analysis of synoptic maps has led to the identification of seven types of synoptic situations for thunderstormy days over the area of Poland. There are four types with characteristic frontal storms: Type 1, a front moving from the western sector connected with a low pressure area situated to the north of Poland; Type 2, similar to Type 1 but with a warm and humid mass of tropical air moving ahead of the front itself; Type 3, a front moving from the North initiated by a high pressure area occurring over Scandinavia; Type 4, with a low pressure centre and accompanying combination of atmospheric fronts over Poland. Two of the identified types of synoptic situations are characterised by days with internal air mass thunderstorms: Type 5, without an atmospheric front and without a high pressure system over Poland; Type 6, with an atmospheric high over the area of Poland. There is also an intermediate type, Type 7, with storms occurring behind the warm atmospheric front moving towards Poland from the South. For the above identified types of synoptic situations an averaged image of the atmospheric pressure field over the area of Europe for both sea level and the height of the 500 hPa geopotential, and any anomalies, was presented by using data concerning the pressure field originating from reanalyses. Applying the correlation research, probability and regression the influence of the above identified seven types on the occurrence of stormy days was defined. Types 2, 4, and 7 bring the most serious likelihood of the occurrence of stormy days. More than 60 of analysed days are related to the activity of cyclonal systems these being Types 1, 2, 3 and 4. Type 2 synoptic situation is identified as the most conducive to the occurrence of days with

  2. Cloud-resolving simulations of mercury scavenging and deposition in thunderstorms

    Directory of Open Access Journals (Sweden)

    U. S. Nair

    2013-10-01

    rainfall from thunderstorms forming in the environmental conditions over the Southeast US compared to the Northeast US. A final simulation of a stratiform rain event produces lower mercury concentrations than in thunderstorms forming in environments typical of the Southeast US. The stratiform cloud scavenges mercury from the lowest ~ 4 km of the atmosphere, while thunderstorms scavenge up to ~ 10 km.

  3. 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

  4. Finite Field Methods for the Supercell Modelling of Charged Insulator-Electrolyte Interfaces

    CERN Document Server

    Zhang, Chao

    2016-01-01

    Surfaces of ionic solids interacting with an ionic solution can build up charge by exchange of ions. The surface charge is compensated by a strip of excess charge at the border of the electrolyte forming an electric double layer. These electric double layers are very hard to model using the supercells methods of computational condensed phase science. The problem arises when the solid is an electric insulator (as most ionic solids are) permitting a finite interior electric field over the width of the slab representing the solid in the supercell. The slab acts as a capacitor. The stored charge is a deficit in the solution failing to compensate fully for the solid surface charge. Here we show how these problems can be overcome using the finite field methods developed by Stengel, Spaldin and Vanderbilt [Nat. Phys. 5, 304, (2009)]. We also show how the capacitance of the double layer can be computed once overall electric neutrality of the double layer is restored by application of a finite macroscopic field E or a...

  5. Simulation of modulated protein crystal structure and diffraction data in a supercell and in superspace

    Energy Technology Data Exchange (ETDEWEB)

    Lovelace, Jeffrey J.; Simone, Peter D. [Eppley Institute for Research in Cancer and Allied Diseases, 987696 Nebraska Medical, Omaha, NE 68198-7696 (United States); Petříček, Václav [Academy of Sciences of the Czech Republic, Na Slovance 10, 182 21 Praha (Czech Republic); Borgstahl, Gloria E. O., E-mail: gborgstahl@unmc.edu [Eppley Institute for Research in Cancer and Allied Diseases, 987696 Nebraska Medical, Omaha, NE 68198-7696 (United States)

    2013-06-01

    A computer simulation was created for a modulated protein structure along with structure factors in a periodic supercell and in superspace for the purpose of developing and validating software modifications that will be used to solve and refine modulated protein crystals. The toolbox for computational protein crystallography is full of easy-to-use applications for the routine solution and refinement of periodic diffraction data sets and protein structures. There is a gap in the available software when it comes to aperiodic crystallographic data. Current protein crystallography software cannot handle modulated data, and small-molecule software for aperiodic crystallography cannot work with protein structures. To adapt software for modulated protein data requires training data to test and debug the changed software. Thus, a comprehensive training data set consisting of atomic positions with associated modulation functions and the modulated structure factors packaged as both a three-dimensional supercell and as a modulated structure in (3+1)D superspace has been created. The (3+1)D data were imported into Jana2006; this is the first time that this has been performed for protein data.

  6. Particle Acceleration Inside Thunderstorms and the Variation in Source Spectra of Terrestrial Gamma-ray Flashes

    Science.gov (United States)

    Cramer, Eric; Dwyer, Joseph R.; Briggs, Michael S.; Rassoul, Hamid K.

    2016-03-01

    One of the unresolved questions in the atmospheric sciences is the origin of Terrestrial Gamma-ray Flashes (TGFs). These flashes are short but intense gamma ray bursts emanating from Earth's atmosphere. This phenomenon has been observed by gamma ray detectors on orbiting satellites, e.g. NASA Fermi, intended to study astrophysical phenomena such as Gamma-ray Bursts. TGFs are thought to originate inside thunderstorms where electrons can be accelerated and emit radiation in the multi MeV range due to bremsstrahlung interactions with air molecules. These so called ``runaway electrons'' are seeded from cosmic ray air showers hitting the Earth's atmosphere from (extra) galactic sources. In this work, we present a Monte Carlo model that simulates particle physics inside a thunderstorm region. The subsequent transport of high energy gamma rays through the Earth's atmosphere and up to satellite orbit is also included. We show that by varying both the potential difference and the ambient electric field inside the thundercloud, different electron and photon energy distributions are produced. This effect may be detectable by orbiting spacecraft, and therefore serves as a method to remote sense the electric fields that exist inside thunderstorms.

  7. Climatic Characteristics of the Thunderstorm Days in Heze City in Recent 51 Years

    Institute of Scientific and Technical Information of China (English)

    LI; Suo-ling; MENG; Rui-juan; SUN; Qiu-sheng; HOU; Wen-jie

    2012-01-01

    [Objective]The research aimed to study climatic characteristics of the thunderstorm days in Heze in recent 51 years. [Method] Using observation data of the thunderstorm days in Heze from 1961 to 2011, interannual and monthly change characteristics of the thunderstorm days, change trends of the first and final dates, interannual stage distribution were analyzed. [Result] Annual average thunderstorm days in Heze was 25 d. As decade increase, thunderstorm days decreased at 1.9 d/10 a. Thunderstorm days concentrated from April to September, and occurred most often in July. The minimum days from first date to final date was 86 d, and the most days was 264 d. Average first date of the thunderstorm was on April 16, and final date was on September 16. Climatic characteristics of the thunderstorm had significant stage. [Conclusion] The research provided scientific basis for prediction, assessment, prevention and reduction of the thunderstorm disaster in Heze.

  8. Simulation of modulated protein crystal structure and diffraction data in a supercell and in superspace.

    Science.gov (United States)

    Lovelace, Jeffrey J; Simone, Peter D; Petříček, Václav; Borgstahl, Gloria E O

    2013-06-01

    The toolbox for computational protein crystallography is full of easy-to-use applications for the routine solution and refinement of periodic diffraction data sets and protein structures. There is a gap in the available software when it comes to aperiodic crystallographic data. Current protein crystallography software cannot handle modulated data, and small-molecule software for aperiodic crystallography cannot work with protein structures. To adapt software for modulated protein data requires training data to test and debug the changed software. Thus, a comprehensive training data set consisting of atomic positions with associated modulation functions and the modulated structure factors packaged as both a three-dimensional supercell and as a modulated structure in (3+1)D superspace has been created. The (3+1)D data were imported into Jana2006; this is the first time that this has been performed for protein data.

  9. A Sensitivity Study of Aerosol Effects on an Idealized Supercell Storm

    Science.gov (United States)

    Takeishi, A.; Storelvmo, T.

    2013-12-01

    One of the largest uncertainties in future climate projections lies in the climatic effects of aerosols. It has been shown that the cooling effect of aerosols could partially offset the current global warming induced by increased greenhouse gas concentration. Among the effects of aerosols, the interaction between aerosols and deep convective clouds is especially difficult to quantify, due to the complex interaction and limited measurements available. Although the radiative effect of deep convective clouds on climate is small, they could affect the local, regional, and global climate by altering precipitation and the large-scale circulations. Thus, it is of importance to understand how deep convection changes its development and evolution with aerosol loading. This study aims to understand the effects of varying aerosol number concentrations on deep convective clouds, using the Weather Research and Forecasting (WRF) model. A quarter-circular shear supercell is simulated with three different microphysics schemes in an idealized setting, while mimicking the changes in aerosol concentration by changing either cloud droplet concentration or activated cloud condensation nuclei concentration. We find that the simulated amount of precipitation has quite different sensitivities to aerosol concentration, depending on the microphysics scheme used; one of the simulations shows a drastic decrease in precipitation with increased aerosol loading, whereas simulations with the other two schemes show relatively low sensitivities to aerosol concentration. This fact highlights uncertainties in the complex microphysical interactions in convective clouds. In addition, changes in ice nuclei concentration are mimicked by changing the ice nucleation rate in each scheme. Sensitivity to this variation is also dependent on the microphysics scheme used. Furthermore, radiation is added in the simulations so that both radiative and microphysical effects of aerosol on the supercell storm are

  10. Extensive air showers, lightning, and thunderstorm ground enhancements

    Science.gov (United States)

    Chilingarian, A.; Hovsepyan, G.; Kozliner, L.

    2016-09-01

    For lightning research, we monitor particle fluxes from thunderclouds, the so-called thunderstorm ground enhancements (TGEs) initiated by runaway electrons, and extensive air showers (EASs) originating from high-energy protons or fully stripped nuclei that enter the Earth's atmosphere. We also monitor the near-surface electric field and atmospheric discharges using a network of electric field mills. The Aragats "electron accelerator" produced several TGEs and lightning events in the spring of 2015. Using 1-s time series, we investigated the relationship between lightning and particle fluxes. Lightning flashes often terminated the particle flux; in particular, during some TGEs, lightning events would terminate the particle flux thrice after successive recovery. It was postulated that a lightning terminates a particle flux mostly in the beginning of a TGE or in its decay phase; however, we observed two events (19 October 2013 and 20 April 2015) when the huge particle flux was terminated just at the peak of its development. We discuss the possibility of a huge EAS facilitating lightning leader to find its path to the ground.

  11. Lightning flash multiplicity in eastern Mediterranean thunderstorms

    Science.gov (United States)

    Yair, Y.; Shalev, S.; Erlich, Z.; Agrachov, A.; Katz, E.; Saaroni, H.; Price, C.; Ziv, B.

    2014-02-01

    Cloud-to-ground lightning flashes usually consist of one or several strokes coming in very short temporal succession and close spatial proximity. A commonly used method for converting stroke data into flashes is using the National Lightning Detection Network (NLDN) thresholds of maximum temporal separation of 0.5 s and maximum lateral distance of 10 km radius between successive strokes. In the present study, we tested a location-based algorithm with several spatial and temporal ranges, and analyzed stroke data obtained by the Israel Lightning Location System (ILLS) during one year (1.8.2009-31.7.2010). We computed the multiplicity, the percentage of single stroke flashes and the geographical distribution of average multiplicity values for thunderstorms in the Eastern Mediterranean region. Results show that for the NLDN thresholds, the percentage of single stroke flashes in Israel was 37% and the average multiplicity was 1.7. We reanalyzed the data with a spatial range that equals twice the ILLS location error and shorter times. For the new thresholds of maximum distance of 2.5 km and maximum allowed temporal separation of 0.2 s we find that the mean multiplicity of negative CGs is lowered to 1.4 and find a percentage of 58% of single stroke flashes. A unique severe storm from 30 October 2009 is analyzed and compared with the annual average of 2009/2010, showing that large deviations from the mean values can occur in specific events.

  12. Spatial and temporal variations of thunderstorm activities over Sri Lanka

    Science.gov (United States)

    Sonnadara, Upul

    2016-05-01

    Spatial and temporal variation of frequencies of thunderstorms over Sri Lanka using thunder day data is presented. A thunder day is simply a calendar day in which thunder is heard at least once at a given location. Two sets of data were collected and analyzed: annual totals for 10 climatological stations for a period of 50 years and monthly totals for 20 climatological stations for a period of 20 years. The average annual thunder days over Sri Lanka was found to be 76. Among the climatological stations considered, a high number of annual thunder days was recorded in Ratnapura (150 days/year), followed by Colombo (108 days/year) and Bandarawela (106 days/year). It appears that there are no widespread long-term increasing or decreasing trends in thunderstorm frequencies. However, Colombo, the capital of Sri Lanka which has over two million people shows an increasing trend of 0.8 thunder days per year. Although there is a high variability between stations reporting the number of thunder days, the overall pattern within a year is clear. Thunderstorm frequencies are high during two periods: March-May and September-November, which coincide with the first inter-monsoon and second inter-monsoon periods. Compared to the dry zone, the wet zone, especially the southwestern region, has high thunderstorm activity. There is a clear spatial difference in thunderstorm activities during the southwest and northeast monsoon seasons. During both these seasons, enhanced thunderstorm activities are reported on the leeward side of the mountain range. A slight reduction in the thunderstorm activities was found in the high elevation areas of the hill country compared to the surrounding areas. A lightning ground flash density map derived using annual thunder days is also presented.

  13. Thunderstorms over a tropical Indian station, Minicoy: Role of vertical wind shear

    Indian Academy of Sciences (India)

    H S Chaudhari; G K Sawaisarje; M R Ranalkar; P N Sen

    2010-10-01

    In this study,an attempt has been made to bring out the observational aspects of vertical wind shear in thunderstorms over Minicoy.Case studies of thunderstorm events have been examined to find out the effect of vertical wind shear and instability on strength and longevity of thunderstorms.Role of vertical wind shear in thunderstorms and its mechanism has been explored in this study.Results reveal that for prolonged thunderstorms high and low instability along with moderate to high vertical wind shear (moderate:0.003S−1 ≤ vertical wind shear ≤ 0.005S−1 and high: < 0.005S−1) play a significant role in longevity and strength of thunderstorms.The mechanism of vertical wind shear in thunderstorms was investigated in a few cases of thunderstorm events where the duration of thunderstorm was covered by the radiosonde/rawin ascent observation taken at Minicoy. Empirical model has been developed to classify thunderstorm type and to determine the strength and longevity of thunderstorms.Model validation has been carried out for selected cases.Model could classify thunderstorm type for most of the cases of thunderstorm events over island and coastal stations.

  14. Heavy Thunderstorm Synoptic Climatology and Forcing Mechanisms in Saudi Arabia.

    Science.gov (United States)

    Ghulam, Ayman S.

    2010-05-01

    Meteorologists are required to provide accurate and comprehensive weather information for planning and operational aviation, agricultural, water projects and also for the public. In general, weather phenomena such as thunderstorms over the area between the tropics and the middle latitudes are not fully understood, particularly in the Middle East area, for many reasons such as: 1) the complexity of the nature of the climate due to the wide-ranging diversity in the topography and landscape in the area; 2) the lack of meteorological data in the area; and 3) the lack of studies on local weather situations. In arid regions such as Saudi Arabia, the spatial and temporal variation of thunderstorms and associated rainfall are essential in determining their effects on social and economic conditions. Thunderstorms form rapidly, due to the fact that the significant heating of the air from the surface and the ensuing rainfall usually occurs within a short period of time. Thus, understanding thunderstorms and rainfall distribution in time and space would be useful for hydrologists, meteorologists and for environmental studies. Research all over the world has shown, however, that consideration of local factors like Low Level Jets (LLJ), moisture flux, sea breezes, and the Red Sea Convergence Zone (RSCZ) would be valuable in thunderstorm prediction. The combined effects of enhanced low-level moisture convergence and layer destabilization due to upslope flow over mountainous terrain has been shown to be responsible for thunderstorm development in otherwise non-favourable conditions. However, there might be other synoptic features associated with heavy thunderstorms or cause them, but these features have not been investigated in any research in Saudi Arabia. Thus, relating the local weather and synoptic situations with those over the middle latitudes will provide a valuable background for the forecasters to issue the medium-range forecasts which are important for many projects

  15. Thunderstorm incidence in southeastern Brazil estimated from different data sources

    Directory of Open Access Journals (Sweden)

    O. Pinto Jr.

    2013-07-01

    Full Text Available This paper describes a comparative analysis of the thunderstorm incidence in southeastern Brazil obtained from thunderstorm days observed at two different epochs (from 1910 to 1951 and from 1971 to 1984 and from lightning data provided by the Brazilian lightning location system RINDAT (from 1999 to 2006 and the Lightning Imaging Sensor (LIS on board the Tropical Rainfall Measuring Mission (TRMM satellite (from 1998 to 2010. The results are interpreted in terms of the main synoptic patterns associated with thunderstorm activity in this region, indicating that the prevailing synoptic pattern associated with thunderstorm activity is the occurrence of frontal systems and their modulation by the South Atlantic Convergence Zone (SACZ and topography. Evidence of urban effects is also found. The results are also discussed in the context of practical applications involving their use in the Brazilian lightning protection standards, suggesting that the present version of the Brazilian standards should be revised incorporating RINDAT and LIS data. Finally, the results are important to improve our knowledge about the limitations of the different techniques used to record the thunderstorm activity and support future climatic studies.

  16. On the robustness of aerosol effects on an idealized supercell storm simulated with a cloud system-resolving model

    Directory of Open Access Journals (Sweden)

    H. Morrison

    2012-08-01

    Full Text Available A cloud system-resolving model (the Weather Research and Forecasting model with 1 km horizontal grid spacing is used to investigate the response of an idealized supercell storm to increased cloud droplet concentrations associated with polluted conditions. The primary focus is on exploring robustness of simulated aerosol effects in the face of complex process interactions and feedbacks between the cloud microphysics and dynamics. Simulations are run using sixteen different model configurations with various microphysical or thermodynamic processes modified or turned off. Robustness of the storm response to polluted conditions is also explored for each configuration by performing additional simulations with small perturbations to the initial conditions. Differences in the domain-mean accumulated surface precipitation and convective mass flux between polluted and pristine conditions are small for almost all model configurations, with relative differences in each quantity generally less than 15%. Configurations that produce a decrease (increase in cold pool strength in polluted conditions also tend to simulate a decrease (increase in surface precipitation and convective mass flux. Combined with an analysis of the dynamical and thermodynamic fields, these results indicate the importance of interactions between microphysics, cold pool evolution, and dynamics along outflow boundaries in explaining the system response. Several model configurations, including the baseline, produce an overall similar storm response (weakening in polluted conditions despite having different microphysical or thermodynamic processes turned off. With hail initiation turned off or the hail fallspeed-size relation set to that of snow, the model produces an invigoration instead of weakening of the storm in polluted conditions. These results highlight the difficulty of foreseeing impacts of changes to model parameterizations and isolating process interactions that drive the system

  17. High-altitude electrical discharges associated with thunderstorms and lightning

    Science.gov (United States)

    Liu, Ningyu; McHarg, Matthew G.; Stenbaek-Nielsen, Hans C.

    2015-12-01

    The purpose of this paper is to introduce electrical discharge phenomena known as transient luminous events above thunderstorms to the lightning protection community. Transient luminous events include the upward electrical discharges from thunderstorms known as starters, jets, and gigantic jets, and electrical discharges initiated in the lower ionosphere such as sprites, halos, and elves. We give an overview of these phenomena with a focus on starters, jets, gigantic jets, and sprites, because similar to ordinary lightning, streamers and leaders are basic components of these four types of transient luminous events. We present a few recent observations to illustrate their main properties and briefly review the theories. The research in transient luminous events has not only advanced our understanding of the effects of thunderstorms and lightning in the middle and upper atmosphere, but also improved our knowledge of basic electrical discharge processes critical for sparks and lightning.

  18. Relationship between lightning activity and vertical airflow characteristics in thunderstorms

    Science.gov (United States)

    Wang, Chenxi; Zheng, Dong; Zhang, Yijun; Liu, Liping

    2017-07-01

    Cloud-to-ground (CG) lightning data, wind field data derived from dual-Doppler radars, and radar reflectivity data are combined to investigate the relationships between CG lightning and the parameters associated with vertical airflow. A new method for the identification of thunderstorm cells based on the aggregation of flashes is developed. It is found that approximately 79.1% of CG flashes are located in the region featuring weak vertical velocity at the 0 °C level, ranging from - 5 to 5 m s- 1, with the majority in the weak updraft region, especially for negative CG lightning and the CG lightning in the initial stage of thunderstorms. The CG lightning rate is correlated with the volume of updraft for vertical velocities within certain limits. The sum of absolute precipitation ice mass flux in the region from 7 to 11 km is more significantly correlated with the CG flash rate, with correlation coefficients of 0.73, 0.71, and 0.74 for the initial, mature, and dissipating stages of thunderstorms, respectively. On average, the updraft in the thunderstorm at the stage when the last CG flash occurs accounts for a much smaller ratio to the whole volume of the thunderstorm than that corresponding to the first CG flash. The maximum updraft and maximum height of the 10 and 20 m s- 1 updraft speeds are close for the first and last CG flashes, indicating the dependence of the lightning on strength of updraft. It is deduced that layered large-range charges may be more conducive to the generation of CG flashes than charge pockets in the thunderstorm.

  19. Simulation of the impact of thunderstorm activity on atmospheric gas composition

    Science.gov (United States)

    Smyshlyaev, S. P.; Mareev, E. A.; Galin, V. Ya.

    2010-08-01

    A chemistry-climate model of the lower and middle atmosphere has been used to estimate the sensitivity of the atmospheric gas composition to the rate of thunderstorm production of nitrogen oxides at upper tropospheric and lower stratospheric altitudes. The impact that nitrogen oxides produced by lightning have on the atmospheric gas composition is treated as a subgrid-scale process and included in the model parametrically. The natural uncertainty in the global production rate of nitrogen oxides in lightning flashes was specified within limits from 2 to 20 Tg N/year. Results of the model experiments have shown that, due to the variability of thunderstorm-produced nitrogen oxides, their concentration in the upper troposphere and lower stratosphere can vary by a factor of 2 or 3, which, given the influence of nitrogen oxides on ozone and other gases, creates the potential for a strong perturbation of the atmospheric gas composition and thermal regime. Model calculations have shown the strong sensitivity of ozone and the OH hydroxyl to the amount of lightning nitrogen oxides at different atmospheric altitudes. These calculations demonstrate the importance of nitrogen oxides of thunderstorm origin for the balance of atmospheric odd ozone and gases linked to it, such as ozone and hydroxyl radicals. Our results demonstrate that one important task is to raise the accuracy of estimates of the rate of nitrogen oxide production by lightning discharges and to use physical parametrizations that take into account the local lightning effects and feedbacks arising in this case rather than climatological data in models of the gas composition and general circulation of the atmosphere.

  20. Interference and k-point sampling in the supercell approach to phase-coherent transport - art. no. 0333401

    DEFF Research Database (Denmark)

    Thygesen, Kristian Sommer; Jacobsen, Karsten Wedel

    2005-01-01

    We present a systematic study of interference and k-point sampling effects in the supercell approach to phase-coherent electron transport. We use a representative tight-binding model to show that interference between the repeated images is a small effect compared to the error introduced by using...... only the Gamma-point for a supercell containing (3,3) sites in the transverse plane. An insufficient k-point sampling can introduce strong but unphysical features in the transmission function which can be traced to the presence of van Hove singularities in the lead. We present a first......-principles calculation of the transmission through a Pt contact which shows that the k-point sampling is also important for realistic systems....

  1. 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.

  2. 湖北宜昌超级单体风暴发生的环境条件分析%Analysis on environment conditions of supercell storms over Yichang, Hubei province

    Institute of Scientific and Technical Information of China (English)

    汪应琼; 李芳; 姜玉印; 王仁乔; 付培健

    2013-01-01

      利用Micaps高空、地面实况资料以及雷达基数据产品资料,分析2004—2009年湖北宜昌境内出现的10例强对流天气过程中的超级单体风暴生成的环境条件和回波结构。结果表明:产生冰雹的湿层相对浅薄,产生强降水的湿层较深厚。使用雷暴发生前地面温度和露点进行订正后的CAPE值可判断午后是否有冰雹发生:若订正后CAPE值有较大幅度增长,其值超过1000 J·kg-1以上,则出现冰雹的可能性较大;反之则小。0—6 km中等到强的垂直风切变有利超级单体风暴生成和发展,垂直风切变越大,越有利出现极端大风。若超级单体风暴高度的特征值和特征底有迅速下降迹象,则未来0.5 h内很可能出现8级以上大风。超级单体风暴中正负速度对的切变值越大,风力越大,风灾越明显。超级单体风暴反射率因子的低层或表现为钩状、或向着入流方向突起、或密实块状等回波特征,中高层有强度达55 dBz的强回波。超级单体风暴中,中气旋大多从逆风区或切变区中发展而来,且其在垂直气流结构上表现为低层气旋式辐合,中层辐合逐渐增强,为气旋式旋转,有时出现气旋式旋转与反气旋式旋转共存的双涡结构,至高层,则转为反气旋,表现为辐散。VIL密度(D VIL)对大冰雹有一定的指示意义,当D VIL≥3.5 g·m-3时,出现直径超过2 cm的大冰雹的可能性非常大。%Using real-time upper-air and surface observations from Micaps and radar based data, the environmental condition and echo structure of supercell storms in 10 severe convective weathers over Yichang, Hubei province from 2004 to 2009 have been analyzed. The re-sults show that hail occurred in shallow wet layer, but severe precipitation occurred in deep wet layer. CAPE revised by ground temperature and dew point before the thunderstorm occurred can be used to judge whether the hail will

  3. Thunderstorm Research International Program (TRIP 77) report to management

    Science.gov (United States)

    Taiani, A. J.

    1977-01-01

    A post analysis of the previous day's weather, followed by the day's forecast and an outlook on weather conditions for the following day is given. The normal NOAA weather charts were used, complemented by the latest GOES satellite pictures, the latest rawinsonde sounding, and the computer-derived thunderstorm probability forecasts associated with the sounding.

  4. Extreme weather caused by concurrent cyclone, front and thunderstorm occurrences

    Science.gov (United States)

    Dowdy, Andrew J.; Catto, Jennifer L.

    2017-01-01

    Phenomena such as cyclones, fronts and thunderstorms can cause extreme weather in various regions throughout the world. Although these phenomena have been examined in numerous studies, they have not all been systematically examined in combination with each other, including in relation to extreme precipitation and extreme winds throughout the world. Consequently, the combined influence of these phenomena represents a substantial gap in the current understanding of the causes of extreme weather events. Here we present a systematic analysis of cyclones, fronts and thunderstorms in combination with each other, as represented by seven different types of storm combinations. Our results highlight the storm combinations that most frequently cause extreme weather in various regions of the world. The highest risk of extreme precipitation and extreme wind speeds is found to be associated with a triple storm type characterized by concurrent cyclone, front and thunderstorm occurrences. Our findings reveal new insight on the relationships between cyclones, fronts and thunderstorms and clearly demonstrate the importance of concurrent phenomena in causing extreme weather.

  5. High-energy radiation from thunderstorms and lightning with LOFT

    CERN Document Server

    Marisaldi, M; Brandt, S; Briggs, M S; Budtz-Jørgensen, C; Campana, R; Carlson, B E; Celestin, S; Connaughton, V; Cummer, S A; Dwyer, J R; Fishman, G J; Fullekrug, M; Fuschino, F; Gjesteland, T; Neubert, T; Østgaard, N; Tavani, M

    2015-01-01

    This is a White Paper in support of the mission concept of the Large Observatory for X-ray Timing (LOFT), proposed as a medium-sized ESA mission. We discuss the potential of LOFT for the study of high-energy radiation from thunderstorms and lightning. For a summary, we refer to the paper.

  6. A virtual tornadic thunderstorm enabling students to construct knowledge about storm dynamics through data collection and analysis

    Directory of Open Access Journals (Sweden)

    W. A. Gallus Jr.

    2006-01-01

    Full Text Available A visually realistic tornadic supercell thunderstorm has been constructed in a fully immersive virtual reality environment to allow students to better understand the complex small-scale dynamics present in such a storm through data probing. Less-immersive versions have been created that run on PCs, facilitating broader dissemination. The activity has been tested in introductory meteorology classes over the last four years. An exercise involving the virtual storm was first used by a subset of students from a large introductory meteorology course in spring 2002. Surveys were used at that time to evaluate the impact of this activity as a constructivist learning tool. More recently, data probe capabilities were added to the virtual storm activity enabling students to take measurements of temperature, wind, pressure, relative humidity, and vertical velocity at any point within the 3-D volume of the virtual world, and see the data plotted via a graphical user interface. Similar surveys applied to groups of students in 2003 and 2004 suggest that the addition of data probing improved the understanding of storm-scale features, but the improved understanding may not be statistically significant when evaluated using quizzes reflecting short-term retention. The use of the activity was revised in 2005 to first have students pose scientific questions about these storms and think about a scientific strategy to answer their questions before exploring the storm. Once again, scores on quizzes for students who used the virtual storm activity were slightly better than those of students who were exposed to only a typical lecture, but differences were not statistically significant.

  7. Alpine debris flows triggered by a 28 July 1999 thunderstorm in the central Front Range, Colorado

    Science.gov (United States)

    Godt, Jonathan W.; Coe, Jeffrey A.

    2007-02-01

    On 28 July 1999, about 480 alpine debris flows were triggered by an afternoon thunderstorm along the Continental Divide in Clear Creek and Summit counties in the central Front Range of Colorado. The thunderstorm produced about 43 mm of rain in 4 h, 35 mm of which fell in the first 2 h. Several debris flows triggered by the storm impacted Interstate Highway 70, U.S. Highway 6, and the Arapahoe Basin ski area. We mapped the debris flows from color aerial photography and inspected many of them in the field. Three processes initiated debris flows. The first process initiated 11% of the debris flows and involved the mobilization of shallow landslides in thick, often well vegetated, colluvium. The second process, which was responsible for 79% of the flows, was the transport of material eroded from steep unvegetated hillslopes via a system of coalescing rills. The third, which has been termed the "firehose effect," initiated 10% of the debris flows and occurred where overland flow became concentrated in steep bedrock channels and scoured debris from talus deposits and the heads of debris fans. These three processes initiated high on steep hillsides (> 30°) in catchments with small contributing areas (material along their paths.

  8. 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

    During the summers of 2003 to 2006 sprites were observed over thunderstorms in France by cameras on mountain tops in Southern France. The observations were part of a larger coordinated effort, the EuroSprite campaigns, with data collected simultaneously from other sources including the French radar...... network for precipitation structure, Meteosat with images of cloud top temperature and the Météorage network for detection of cloud-to-ground (CG) flash activity. In this paper two storms are analyzed, each producing 27 sprite events. Both storms were identified as Mesoscale Convective Systems (MCS......) with a trailing stratiform configuration (ST) and reaching a maximum cloud area of ~ 120,000 km2. Most of the sprites were produced while the stratiform area was clearly developed and during periods of substantial increase of rainfall in regions with radar reflectivity between 30 and 40 dBZ. The sprite...

  9. A Numerical Simulation of the 12 July 1996 STERAO Thunderstorm

    Science.gov (United States)

    Zimmerman, A. J.; Helsdon, J. H.; Farley, R. D.

    2005-12-01

    We utilize our three-dimensional Storm Electrification Model with an explicit lightning scheme and chemistry to simulate the 12 July 1996 thunderstorm that occurred in northeastern Colorado during the Stratospheric-Tropospheric Experiment: Radiation, Aerosols and Ozone (STERAO) Deep Convection Field Project. The NO production is based on the energy dissipation of the lightning discharge with a pressure dependence included. The chemistry module has nine species, including NO, NO2, O3, and CH4, but does not include non-methane hydrocarbons. There are eighteen reactions among the nine species, three of which are photolytic. We focus on the production of NOx (NO + NO2) by lightning within the model and compare our results to airborne measurements obtained during the thunderstorm.

  10. Global scale ionospheric irregularities associated with thunderstorm activity

    CERN Document Server

    Pulinets, S A

    2002-01-01

    The potential difference near 280 kV exists between ground and ionosphere. This potential difference is generated by thunderstorm discharges all over the world, and return current closes the circuit in the areas of fair weather (so-called fair weather current). The model calculations and experimental measurements clearly demonstrate non-uniform latitude-longitude distribution of electric field within the atmosphere. The recent calculations show that the strong large scale vertical atmospheric electric field can penetrate into the ionosphere and create large scale irregularities of the electron concentration. To check this the global distributions of thunderstorm activity obtained with the satellite monitoring for different seasons were compared with the global distributions of ionosphere critical frequency (which is equivalent to peak electron concentration) obtained with the help of satellite topside sounding. The similarity of the obtained global distributions clearly demonstrates the effects of thunderstor...

  11. Beaming Properties of Energetic Electrons and Photons Inside Thunderstorms

    Science.gov (United States)

    Cramer, Eric; Briggs, Michael

    2017-01-01

    It has been well established that thunderstorm environments allow relativistic runaway electron avalanches (RREAs) to develop under the influence of strong electric fields. This process can be seeded by external sources, such as cosmic-ray secondary electrons. The resulting bremsstrahlung x-rays and gamma rays that are emitted, propagate through the atmosphere and into space where they are detected by orbiting spacecraft, e.g. NASA Fermi. These high energy radiation blasts are known as Terrestrial Gamma-ray Flashes (TGFs). Using a Monte Carlo particle simulation, we show beaming characteristics of these electrons and photons such as the angular distribution, energy spectra, and the radial distribution from the thunderstorm source to the observation point of orbiting spacecraft. These features are related to the thunderstorm electric field, Earth's geomagnetic field, and the potential inside the thundercloud region. Observations of TGFs made by the Gamma-ray Burst Monitor (GBM) will also be discussed, as well as a future multipoint CubeSat mission targeted to measure the beaming geometry of the gamma rays. This material is based upon work supported by the National Science Foundation under Grant Number 1524533.

  12. THUNDERSTORMS-RISK FACTORS IN AVIATION. CASE STUDY: AREA OF RESPONSABILITY OF THE BUCHAREST-OTOPENI AERODROME ON 30.06.2009

    Directory of Open Access Journals (Sweden)

    C. L. ŞCHIOPU

    2015-10-01

    Full Text Available Thunderstorms are always dangerous weather phenomena for flight safety and, irrespective of their nature, they have a negative impact on all aviation activities. Thunderstorm clouds can generate severe and rapid changes of various meteorological elements (visibility, cloudiness and cloud lower base, wind, sometimes to such a great extent that landing may become impossible. Thunderstorms are serious weather hazards in aviation and may produce great damage and even casualties. One such unfortunate aviation event took place in the vicinity of the Bucharest-Otopeni Aerodrome, on 30.06.2009, when a military aircraft, which was operating a training flight in the responsibility area of the Bucharest - Otopeni military aerodrome, was struck by lightning at local hour 18:20. The present study actually makes an inventory of the extremely hazardous flying conditions, by thoroughly analyzing the relevant weather reports and data, as well as visual and synoptic messages from that very day. All these materials showed that the airdrome of destination was under the influence of an anti-cyclonic ridge, which accounted for the very poor meteorological conditions. On such severe weather, although the crew members tried to avoid the Cumulonimbus clouds in which a severe thunderstorm was developing, the flight was put in danger since the aircraft was struck by lightning, which simply blurred out the radar system and, therefore, landmarks orientation became almost impossible, thus creating false perceptions to the pilots trying hard to stabilize the plane.

  13. Apparent Negative Reflection with the Gradient Acoustic Metasurface by Integrating Supercell Periodicity into the Generalized Law of Reflection

    Science.gov (United States)

    Liu, Bingyi; Zhao, Wenyu; Jiang, Yongyuan

    2016-12-01

    As the two dimensional version of the functional wavefront manipulation metamaterial, metasurface has become a research hot spot for engineering the wavefront at will with a subwavelength thickness. The wave scattered by the gradient metasurface, which is composed by the periodic supercells, is governed by the generalized Snell’s law. However, the critical angle that derived from the generalized Snell’s law circles the domain of the incident angles that allow the occurrence of the anomalous reflection and refraction, and no free space scattering waves could exist when the incident angle is beyond the critical angle. Here we theoretically demonstrate that apparent negative reflection can be realized by a gradient acoustic metasurface when the incident angle is beyond the critical angle. The underlying mechanism of the apparent negative reflection is understood as the higher order diffraction arising from the interaction between the local phase modulation and the non-local effects introduced by the supercell periodicity. The apparent negative reflection phenomena has been perfectly verified by the calculated scattered acoustic waves of the reflected gradient acoustic metasurface. This work may provide new freedom in designing functional acoustic signal modulation devices, such as acoustic isolator and acoustic illusion device.

  14. Apparent Negative Reflection with the Gradient Acoustic Metasurface by Integrating Supercell Periodicity into the Generalized Law of Reflection.

    Science.gov (United States)

    Liu, Bingyi; Zhao, Wenyu; Jiang, Yongyuan

    2016-12-05

    As the two dimensional version of the functional wavefront manipulation metamaterial, metasurface has become a research hot spot for engineering the wavefront at will with a subwavelength thickness. The wave scattered by the gradient metasurface, which is composed by the periodic supercells, is governed by the generalized Snell's law. However, the critical angle that derived from the generalized Snell's law circles the domain of the incident angles that allow the occurrence of the anomalous reflection and refraction, and no free space scattering waves could exist when the incident angle is beyond the critical angle. Here we theoretically demonstrate that apparent negative reflection can be realized by a gradient acoustic metasurface when the incident angle is beyond the critical angle. The underlying mechanism of the apparent negative reflection is understood as the higher order diffraction arising from the interaction between the local phase modulation and the non-local effects introduced by the supercell periodicity. The apparent negative reflection phenomena has been perfectly verified by the calculated scattered acoustic waves of the reflected gradient acoustic metasurface. This work may provide new freedom in designing functional acoustic signal modulation devices, such as acoustic isolator and acoustic illusion device.

  15. ROMANIAN TERMINOLOGY IN THE METEOROLOGY OF SEVERE WEATHER – CASE STUDY OF THE SUPERCELL FROM ARAD COUNTRY ON THE 14TH OF JUNE 2010

    Directory of Open Access Journals (Sweden)

    O. SCRIDONESI

    2011-03-01

    Full Text Available Romanian terminology in the meteorology of severe weather – Case study of the supercell from the 14th of June 2010. Using the ingredients-based methodology, the low precipitation supercell storm from the 14th of June 2010 in the Arad county is analyzed in terms of conditions of development, evolution and structure. To address such a topic an important issue is the lack of meteorological terms in the Romanian language to enable the completion of such analysis of supercell storms or other severe weather phenomena. Finding terms that correspond to the best of the English language during the analysis is performed either by direct translation into romanian, either by replacing the terms that best fit the context and the use of each term is motivated.

  16. Avalanche-to-streamer transition near hydrometeors in thunderstorms

    Science.gov (United States)

    Rutjes, Casper; Dubinova, Anna; Ebert, Ute; Buitink, Stijn; Scholten, Olaf; Trinh, Gia

    2016-04-01

    In the early phase of lightning initiation, streamers must form near water droplets and or ice crystals, collectively called hydrometeors, as it is generally believed that the electric fields in a thunderstorm are below classical breakdown [1]. The hydrometeors, due to their dielectric property, electrically polarize and will enhance the thunderstorm electric field in localized areas just outside the surface, potentially above breakdown. Available electrons, from for example a cosmic ray event, are drawn towards the positive side of the polarized hydrometeor. Some electrons reach the localized area above breakdown, while oxygen molecules have absorbed others. In the area above breakdown electrons begin to multiply in number, creating electron avalanches towards the surface, leaving positive ions behind. This results in a charge separation, which potentially can initiate a positive streamer. The final outcome however strongly depends on several parameters, such as the strength of the thunderstorm electric field, the size and shape of the hydrometeor and the initial amount of electrons. In our letter [1] we introduced a dimensionless quantity M that we call the Meek number, based on the historical and well-used Reather-Meek criterion [2], as a measure of how likely it is to create an avalanche-to-streamer transition near a hydrometeor. Results from simulations showed that streamers can start in a field of only 15% of breakdown from large elongated shaped hydrometeors. Now we extended and generalized our method to arbitrary shaped hydrometeors and we take into account that potentially several electrons can reach the area above breakdown. Due to these effects we can predict smaller hydrometeors to be able to start streamers. We will present the latest results. [1] Dubinova, A., Rutjes, C., Ebert, U., Buitink, S., Scholten, O., & Trinh, G. T. N. (2015). Prediction of lightning inception by large ice particles and extensive air showers. Physical review letters, 115

  17. Sensitivity of land surface and Cumulus schemes for Thunderstorm prediction

    Science.gov (United States)

    Kumar, Dinesh; Mohanty, U. C.; Kumar, Krishan

    2016-06-01

    The cloud processes play an important role in all forms of precipitation. Its proper representation is one of the challenging tasks in mesoscale numerical simulation. Studies have revealed that mesoscale feature require proper initialization which may likely to improve the convective system rainfall forecasts. Understanding the precipitation process, model initial condition accuracy and resolved/sub grid-scale precipitation processes representation, are the important areas which needed to improve in order to represent the mesoscale features properly. Various attempts have been done in order to improve the model performance through grid resolution, physical parameterizations, etc. But it is the physical parameterizations which provide a convective atmosphere for the development and intensification of convective events. Further, physical parameterizations consist of cumulus convection, surface fluxes of heat, moisture, momentum, and vertical mixing in the planetary boundary layer (PBL). How PBL and Cumulus schemes capture the evolution of thunderstorm have been analysed by taking thunderstorm cases occurred over Kolkata, India in the year 2011. PBL and cumulus schemes were customized for WSM-6 microphysics because WSM series has been widely used in operational forecast. Results have shown that KF (PBL scheme) and WSM-6 (Cumulus Scheme) have reproduced the evolution of surface variable such as CAPE, temperature and rainfall very much like observation. Further, KF and WSM-6 scheme also provided the increased moisture availability in the lower atmosphere which was taken to higher level by strong vertical velocities providing a platform to initiate a thunderstorm much better. Overestimation of rain in WSM-6 occurs primarily because of occurrence of melting and freezing process within a deeper layer in WSM-6 scheme. These Schemes have reproduced the spatial pattern and peak rainfall coverage closer to TRMM observation. It is the the combination of WSM-6, and KF schemes

  18. Sensitivity of land surface and Cumulus schemes for Thunderstorm prediction

    Directory of Open Access Journals (Sweden)

    D. Kumar

    2016-06-01

    Full Text Available The cloud processes play an important role in all forms of precipitation. Its proper representation is one of the challenging tasks in mesoscale numerical simulation. Studies have revealed that mesoscale feature require proper initialization which may likely to improve the convective system rainfall forecasts. Understanding the precipitation process, model initial condition accuracy and resolved/sub grid-scale precipitation processes representation, are the important areas which needed to improve in order to represent the mesoscale features properly. Various attempts have been done in order to improve the model performance through grid resolution, physical parameterizations, etc. But it is the physical parameterizations which provide a convective atmosphere for the development and intensification of convective events. Further, physical parameterizations consist of cumulus convection, surface fluxes of heat, moisture, momentum, and vertical mixing in the planetary boundary layer (PBL. How PBL and Cumulus schemes capture the evolution of thunderstorm have been analysed by taking thunderstorm cases occurred over Kolkata, India in the year 2011. PBL and cumulus schemes were customized for WSM-6 microphysics because WSM series has been widely used in operational forecast. Results have shown that KF (PBL scheme and WSM-6 (Cumulus Scheme have reproduced the evolution of surface variable such as CAPE, temperature and rainfall very much like observation. Further, KF and WSM-6 scheme also provided the increased moisture availability in the lower atmosphere which was taken to higher level by strong vertical velocities providing a platform to initiate a thunderstorm much better. Overestimation of rain in WSM-6 occurs primarily because of occurrence of melting and freezing process within a deeper layer in WSM-6 scheme. These Schemes have reproduced the spatial pattern and peak rainfall coverage closer to TRMM observation. It is the the combination of WSM-6

  19. Debris Flows and Record Floods from Extreme Mesoscale Convective Thunderstorms over the Santa Catalina Mountains, Arizona

    Science.gov (United States)

    Magirl, Christopher S.; Shoemaker, Craig; Webb, Robert H.; Schaffner, Mike; Griffiths, Peter G.; Pytlak, Erik

    2007-01-01

    Ample geologic evidence indicates early Holocene and Pleistocene debris flows from the south side of the Santa Catalina Mountains north of Tucson, Arizona, but few records document historical events. On July 31, 2006, an unusual set of atmospheric conditions aligned to produce record floods and an unprecedented number of debris flows in the Santa Catalinas. During the week prior to the event, an upper-level area of low pressure centered near Albuquerque, New Mexico generated widespread heavy rainfall in southern Arizona. After midnight on July 31, a strong complex of thunderstorms developed over central Arizona in a deformation zone that formed on the back side of the upper-level low. High atmospheric moisture (2.00' of precipitable water) coupled with cooling aloft spawned a mesoscale thunderstorm complex that moved southeast into the Tucson basin. A 15-20 knot low-level southwesterly wind developed with a significant upslope component over the south face of the Santa Catalina Mountains advecting moist and unstable air into the merging storms. National Weather Service radar indicated that a swath of 3-6' of rainfall occurred over the lower and middle elevations of the southern Santa Catalina Mountains. This intense rain falling on saturated soil triggered over 250 hillslope failures and debris flows throughout the mountain range. Sabino Canyon, a heavily used recreation area administered by the U.S. Forest Service, was the epicenter of mass wasting, where at least 18 debris flows removed structures, destroyed the roadway in multiple locations, and closed public access for months. The debris flows were followed by streamflow floods which eclipsed the record discharge in the 75-year gaging record of Sabino Creek. In five canyons adjacent to Sabino Canyon, debris flows approached or excited the mountain front, compromising floow conveyance structures and flooding some homes.

  20. Climate change signal of thunderstorm frequency using high-resolution COSMO-CLM simulations

    Science.gov (United States)

    Schefczyk, Lukas; Heinemann, Guenther

    2014-05-01

    It is generally assumed that temperature increase associated with global climate change will lead to increased thunderstorm intensity and associated heavy precipitation events. In the present study it is investigated whether the frequency of thunderstorm occurrences will in- or decrease and how the spatial distribution will change for the A1B scenario. The region of interest is Saar-Lor-Lux region (Saarland, Lorraine, Luxembourg) with a focus on Rhineland-Palatinate. Hourly and daily model data of the COSMO-CLM is used with a horizontal resolution of 4.5km and 1.3km. The simulations were carried out for three different decades: 1991-2000 (C20), 2041-2050 (A1B) and 2091-2100 (A1B). Thunderstorm indices are calculated to detect potential thunderstorms and differences in their frequency of occurrence in the three decades. The indices used are CAPE (Convective Available Potential Energy), SLI (Surface Lifted Index), and TSP (Thunderstorm Severity Potential), which combines deep-layer-shear and the maximum vertical velocity. The significance of a potential climate signal was tested with a t-test and a power analysis was performed to quantify the uncertainty of the signal. The investigation of the present and future thunderstorms shows that the regional averaged frequencies will decrease in general, but several regions like the Saarland and especially elevated areas will have a potential increase in thunderstorm occurrences and intensity. Statistically, nearly none of the signals is significant and the power analysis yields low power to detect changes of severe thunderstorms but high power for classes with no to light thunderstorms. Therefore it can be concluded that the frequency of severe thunderstorm is not likely to increase.

  1. Early warnings of hazardous thunderstorms over Lake Victoria

    Science.gov (United States)

    Thiery, Wim; Gudmundsson, Lukas; Bedka, Kristopher; Semazzi, Fredrick H. M.; Lhermitte, Stef; Willems, Patrick; van Lipzig, Nicole P. M.; Seneviratne, Sonia I.

    2017-07-01

    Weather extremes have harmful impacts on communities around Lake Victoria in East Africa. Every year, intense nighttime thunderstorms cause numerous boating accidents on the lake, resulting in thousands of deaths among fishermen. Operational storm warning systems are therefore crucial. Here we complement ongoing early warning efforts based on numerical weather prediction, by presenting a new satellite data-driven storm prediction system, the prototype Lake Victoria Intense storm Early Warning System (VIEWS). VIEWS derives predictability from the correlation between afternoon land storm activity and nighttime storm intensity on Lake Victoria, and relies on logistic regression techniques to forecast extreme thunderstorms from satellite observations. Evaluation of the statistical model reveals that predictive power is high and independent of the type of input dataset. We then optimise the configuration and show that false alarms also contain valuable information. Our results suggest that regression-based models that are motivated through process understanding have the potential to reduce the vulnerability of local fishing communities around Lake Victoria. The experimental prediction system is publicly available under the MIT licence at http://github.com/wthiery/VIEWS.

  2. Characteristics of Lightning Discharges and Electric Structure of Thunderstorm

    Institute of Scientific and Technical Information of China (English)

    Qie Xiushu; Zhang Yijun; Zhang Qilin

    2006-01-01

    Progresses in the research on physical processes of lightning discharge and electric structure of thunderstorm in the last decade in China have been reviewed. By using the self-developed lightning detecting and locating techniques with high temporal and spatial resolution, the characteristics and parameters of lightning discharge in some representative areas in China have been obtained. Observations on lightning activity were conducted for the first time in the Qinghai-Tibetan Plateau in 2002-2005, and the special characteristics of the thunderstorm and lightning activity in the plateau were revealed. The lightning spectra in the band of visible light were recorded, and the spectral lines were identified in detail with introduction of modern theories of atomic structure. The techniques on artificially altitude triggered lightning and related measurements under a harsh electromagnetic environment have been well developed. Evidences of bi-directional leader propagation were observed by means of optics and VHF radiation during the triggered lightning discharges. Some lightning protection devices have been tested using the artificial lightning triggering techniques. In addition, the correlation between lightning activities and weather and climate was preliminarily studied.

  3. A Radar-Based Climatology of Thunderstorm Days across New York State.

    Science.gov (United States)

    Falconer, Phillip D.

    1984-07-01

    Archived radar reports, derived from the National Weather Service radar network, were used to estimate the average annual frequencies of thunderstorm days across New York State for the period 1978-81. The archival records consist of manually-digitized radar (MDR) data, available on magnetic tapes and arranged as hourly, digitally-encoded radar reflectivity values within a high-resolution grid of reporting blocks, each 45 × 45 km. Analyses of these data made use of an experimentally-derived relationship between radar reflectivities and the presence and intensities of thunderstorms. The radar-based thunderstorm day climatology generally agreed to within 15% of conventional, surface-based thunderstorm day statistics reported for the same period by National Weather Service (NWS) offices located within range of two or more network radars in the State. Poorest agreement between annual totals was found at selected NWS offices in the Greater New York City Metropolitan Area and northward into the lower Hudson River Valley, in far western New York and over far northern New York. Where redundant, near-continuous network radar coverage was available, a northwest-to-southeast increase of thunderstorm days, approaching an annual maximum of 45 in downstate New York was revealed. This gradient in thunderstorm day activity is significantly different from that depicted on isokeraunic maps derived from conventional thunder observing protocol. Because the MDR data are archived on a high-resolution grid of reporting blocks, local thunderstorm maxima on a scale of tens of kilometers may be resolved. Analyses further revealed that 5-25% of all thunderstorm days contained sufficiently vigorous storms to be characterized as `intense'. The greatest frequency of intense thunderstorm days, approaching 8 annually, was located in the highly-populated region of the State along the New York-New Jersey borders, northwest of the Greater New York City Metropolitan Area.

  4. Space-Borne Observations of Intense Gamma-Ray Flashes (TGFs) Above Thunderstorms

    Science.gov (United States)

    Fishman, Gerald J.

    2010-01-01

    Intense millisecond flashes of MeV photons are being observed with space-borne detectors. These terrestrial gamma-ray flashes (TGFs) were discovered with the Burst and Transient Source Experiment (BATSE) aboard the Compton Gamma-Ray Observatory (CGRO) in the early 1990s. They are now being observed with several other instruments, including the Gamma-ray Burst Monitor (GBM) detectors on the Fermi Gamma-ray Space Telescope. Although Fermi-GBM was designed and optimized for the observation of cosmic gamma-ray bursts (GRBs), it has unprecedented capabilities for TGF observations. The TGFs usually have extremely hard continuous spectra, typical of highly-Comptonized bremsstrahlung radiation. These spectral are harder than those of GRBs, with photons extending to over 40 MeV. The most likely origin of these high-energy photons is bremsstrahlung radiation produced by a relativistic runaway avalanche electron beam. Such a beam is expected to be produced in an extended, intense electric field in or above thunderstorm regions. The altitude of origin and beaming characteristics of the radiation are quite uncertain. These TGFs may produce an appreciable radiation dose to passengers and crew in nearby aircraft. They have generated considerable observational and theoretical interest in recent years. Instruments are being designed specifically for TGF observations from new spacecraft as well as from airborne platforms.

  5. Effects of the Inductive Charging on the Electrification and Lightning Discharges in Thunderstorms

    Directory of Open Access Journals (Sweden)

    Zheng Shi

    2016-04-01

    Full Text Available A two-dimensional cloud model with electrification and lightning processes is used to investigate the role of inductive charge separation in thunderstorm clouds. For the same dynamic and microphysical evolution, four cases that the same non-inductive charging parameterization is combined with different inductive charging process are compared. Non-inductive charge separation alone is found to be sufficient to produce a dipolar charge structure. Intracloud (IC and positive cloud-to-ground (+CG flashes are initiated between a main negative charge region and an upper positive charge region. The inductive charging process between graupel and cloud droplets exhibits a normal tripole charge structure, consisting of a lower positive charge region under the main negative charge region. In the simulated tripole structure, negative cloud-to-ground (-CG flashes are initiated between the main negative and lower positive charge regions. In addition, inductive charge separation between the graupel and ice crystal is found to be capable of producing strong charge separation in a dipole charge structure. Tests with inductive graupel-ice crystals process produce more flashes than that in the other cases.

  6. Very-Low-Frequency Subionospheric Remote Sensing of Thunderstorm-driven Acoustic and Gravity Waves in the D-region

    Science.gov (United States)

    Marshall, R. A.; Snively, J. B.

    2013-12-01

    We present observations of thunderstorm-driven perturbations to the D-region ionosphere measured by VLF subionospheric remote sensing (VLF-SRS). VLF-SRS is sensitive to electron density and collision frequency disturbances in a narrow altitude range near 85 km along the great-circle-path (GCP) between a VLF transmitter and a receiver some thousands of km away. These disturbances are measured as amplitude and/or phase perturbations to the continuous VLF transmitter signal. On March 20, 2001, a prominent event was observed by VLF receivers in Colorado monitoring the VLF transmitter in Puerto Rico, exhibiting unusually strong amplitude perturbations of up to 0.6 dB, with periods of 1-3 minutes, but no detectable phase perturbations. As these periods are well below the minimum Brunt-Vaisala period of about 5 minutes, we hypothesize that they may be associated with thunderstorm-generated acoustic waves (AWs). The GCPs from this transmitter to the receivers passed through two thunderstorms at the time of the AW event, one near the southern tip of Florida and the other over the Florida panhandle. The apparent AW event lasted for about one hour and was observed on four near-parallel GCPs separated by a few tens of km at the thunderstorm location. This data shows that VLF-SRS may provide a new, high-time-resolution (better than 1 Hz) monitoring system for acoustic and gravity waves in the upper atmosphere. To investigate the hypothesized AW source for this event, we use a two-step simulation process. A nonlinear, compressible, atmospheric dynamics model is used to simulate acoustic wave propagation from a defined source near the ground to 200 km altitude. Case studies are constructed to investigate different source configurations and perturbations to ionospheric density profiles. The modified electron and neutral density are then input to a finite-difference electromagnetic code that simulates the VLF transmitter signal propagation to the receiver over a distance of ~5000

  7. CloudSat Image of Tropical Thunderstorms Over Africa

    Science.gov (United States)

    2006-01-01

    [figure removed for brevity, see original site] Figure 1 CloudSat image of a horizontal cross-section of tropical clouds and thunderstorms over east Africa. The red colors are indicative of highly reflective particles such as water (rain) or ice crystals, which the blue indicates thinner clouds (such as cirrus). The flat green/blue lines across the bottom represent the ground signal. The vertical scale on the CloudS at Cloud Profiling Radar image is approximately 30 kilometers (19 miles). The brown line below the image indicates the relative elevation of the land surface. The inset image shows the CloudSat track relative to a Moderate Resolution Imaging Spectroradiometer (MODIS) visible image taken at nearly the same time.

  8. Transient Thunderstorm Downbursts and Their Effects on Wind Turbines

    Directory of Open Access Journals (Sweden)

    Hieu H. Nguyen

    2014-10-01

    Full Text Available The International Electrotechnical Commission (IEC Standard 61400-1 for the design of wind turbines does not explicitly address site-specific conditions associated with anomalous atmospheric events or conditions. Examples of off-standard atmospheric conditions include thunderstorm downbursts, hurricanes, tornadoes, low-level jets, etc. The simulation of thunderstorm downbursts and associated loads on a utility-scale wind turbine is the focus of this study. Since the problem has not received sufficient attention, especially in terms of design, we thus focus in this paper on practical aspects. A wind field model that incorporates component non-turbulent and turbulent parts is described and employed in inflow simulations. The non-turbulent part is based on an available analytical model with some modifications, while the turbulent part is simulated as a stochastic process using standard turbulence power spectral density functions and coherence functions whose defining parameters are related to the downburst characteristics such as the storm translation velocity. Available information on recorded downbursts is used to define two storm scenarios that are studied. Rotor loads are generated using stochastic simulation of the aeroelastic response of a model of a utility-scale 5-MW turbine. An illustrative single storm simulation and the associated turbine response are used to discuss load characteristics and to highlight storm-related and environmental parameters of interest. Extensive simulations for two downbursts are then conducted while varying the storm’s location and track relative to the turbine. Results suggest that wind turbine yaw and pitch control systems clearly influence overall system response. Results also highlight the important effects of both the turbulence as well as the downburst mean wind profiles on turbine extreme loads.

  9. Profuse activity of blue electrical discharges at the tops of thunderstorms

    Science.gov (United States)

    Chanrion, Olivier; Neubert, Torsten; Mogensen, Andreas; Yair, Yoav; Stendel, Martin; Singh, Rajesh; Siingh, Devendraa

    2017-01-01

    Thunderstorm clouds may reach the lower stratosphere, affecting the exchange of greenhouse gases between the troposphere and stratosphere. This region of the atmosphere is difficult to access experimentally, and our knowledge of the processes taking place here is incomplete. We recently recorded color video footage of thunderstorms over the Bay of Bengal from the International Space Station. The observations show a multitude of blue, kilometer-scale, discharges at the cloud top layer at 18 km altitude and a pulsating blue discharge propagating into the stratosphere reaching 40 km altitude. The emissions are related to the so-called blue jets, blue starters, and possibly pixies. The observations are the first of their kind and give a new perspective on the electrical activity at the top of tropical thunderstorms; further, they underscore that thunderstorm discharges directly perturb the chemistry of the stratosphere with possible implications for the Earth's radiation balance.

  10. THE CHARACTERISTICS OF THUNDERSTORM FREQUENCY VARIATION AND THEIR POSSIBLE RELATION WITH THE ADJUSTMENT OF CROP DISTRIBUTION IN THE LEIZHOU PENINSULA

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yu; NIU Sheng-jie

    2009-01-01

    In order to research possible influences of the adjustment of plant distribution on the development frequency of thunderstorms over the Leizhou Peninsula,mathematic statistic methods, including correlation analyses,11 kinds of fitting models and all-variable regression methods,were used for analyses and research. The results show that the average trend of the number of annual thunderstorm days is descending obviously,and there are thunderstorms in all seasons,in which warm post-midday thunderstorms have taken up the most part,and high frequency is found from May to September,and the starting and ending dates of thunderstorms have a great annual discrepancy. The vegetation structure has been improved along with the reduction of rice fields and the area increment of sugarcane and fruits planting,which results in the decrease of the number of thunderstorm days; the change in the characteristics of winter spare fields,which is caused by the planting of vegetables,limits the formation of thunderstorms in early winter and late spring. Meanwhile,the area adjustment of peanut planting has little influence on the variation of thunderstorm days. The adjustment of principal crop distribution,such as rice, sugarcane,fruits and vegetables,may have obvious influence on the formation of thunderstorms,and sugarcane has the largest effect,followed in turn by rice,vegetables and fruits,and the adjustment of crop distribution has little influence on the starting and ending dates of thunderstorms.

  11. Analysis of energetic radiation associated with thunderstorms in the Ebro delta region in Spain

    Science.gov (United States)

    Fabró, Ferran; Montanyà, Joan; Pineda, Nicolau; Argemí, Oriol; Velde, Oscar A.; Romero, David; Soula, Serge

    2016-08-01

    The analysis of high-energy background radiation (0.1-2 MeV) enhancements during eight winter thunderstorms and five summer storms in the Ebro delta region in the northeast of Spain is presented. For the first time, high-energy radiation counts, precipitation, radar reflectivity, and very high frequency lightning detections to infer charge regions altitude have been analyzed in order to find out what produces the measured background radiation increments associated with storms. The good agreement between radar reflectivity and precipitation with increases in background radiation counts coupled with the spectrum analysis comparing rain/no rain periods suggests that radon-ion daughters play a major role in the radiation increments reported. No evidence has been found supporting that measured background radiation enhancements can be produced by storm electric fields. Finally, a single case of a high-energy radiation increase was prior to a cloud-to-ground lightning stroke, which reinforces the theory that a lower positive charge layer's existence is important for the production of Terrestrial Ground Enhancements.

  12. Intense Gamma-Ray Flashes Above Thunderstorms on the Earth and Other Planets

    Science.gov (United States)

    Fishman, Gerald J.

    2010-01-01

    Intense millisecond flashes of MeV photons have been observed with space-borne detectors in Earth orbit. They are expected to be present on other planets that exhibit lightning. The terrestrial gamma-ray flashes (TGFs) were discovered with the Burst and Transient Source Experiment (BATSE) aboard the Compton Gamma-Ray Observatory (CGRO) in the early 1990s. They are now being observed with several other instruments, including the Gamma-ray Burst Monitor (GBM) detectors on the Fermi Gamma-ray Space Telescope. Although Fermi- GBM was designed and optimized for the observation of cosmic gamma-ray bursts (GRBs), it has unprecedented capabilities for TGF observations. The TGFs usually have extremely hard continuous spectra, typical of highly- Comptonized bremsstrahlung radiation. These spectral are harder than those of GRBs, with photons extending to over 40 MeV. The most likely origin of these high-energy photons is bremsstrahlung radiation produced by a relativistic "runaway avalanche" electron beam. Such a beam is expected to be produced in an extended, intense electric field in or above thunderstorm regions. The altitude of origin and beaming characteristics of the radiation are quite uncertain. They have generated considerable observational and theoretical interest in recent years. This talk will give an overview of the all of the space-borne observations of TGFs that have been made thus far. Instruments are being designed specifically for TGF observations from new spacecraft as well as from airborne platforms

  13. Global thunderstorm activity estimation based on number of transients in ELF-band

    Science.gov (United States)

    Ondraskova, Adriena; Sevcik, Sebastian

    2017-04-01

    Schumann resonances (SR) are resonant electromagnetic oscillations in extremely low frequency band (ELF, 3 Hz - 3 kHz), which arise in the Earth-ionosphere cavity due to lightning activity in planetary range. The time records in the ELF-band consist of background signals and ELF transients/Q-bursts superimposed on the background exceeding it by a factor of 5 - 10. The former are produced by the common worldwide thunderstorm activity (100 - 150 events per second), the latter origin from individual intense distant lightning discharges (100 - 120 powerful strokes per hour). A Q-burst is produced by a combination of direct and antipodal pulses and the decisive factor for its shape follows from the source-to-observer distance. Diurnal/seasonal variations of global thunderstorm activity can be deduced from spectral amplitudes of SR modes. Here we focus on diurnal/seasonal variations of the number of ELF-transients assuming that it is another way of lightning activity estimation. To search for transients, our own code was applied to the SR vertical electric component measured in October 2004 - October 2008 at the Astronomical and Geophysical Observatory of FMPI CU, Slovakia. Criteria for the identification of the burst are chosen on the basis of the transient amplitudes and their morphological features. Monthly mean daily variations in number of transients showed that African focus dominates at 14 - 16 h UT and it is more active in comparison with Asian source, which dominates at 5 - 8 h UT in dependence on winter or summer month. American source had surprisingly slight response. Meteorological observations in South America aiming to determine lightning hotspots on the Earth indicate that flash rate in this region is greatest during nocturnal 0 h - 3 h local standard time. This fact may be interpreted that Asian and South American sources contribute together in the same UT. Cumulative spectral amplitude of the first three SR modes compared with number of ELF-transients in

  14. Observations of Sprites and Elves Associated With Winter Thunderstorms in the Eastern Mediterranean

    Science.gov (United States)

    Ganot, M.; Yair, Y.; Price, C.; Ziv, B.; Sherez, Y.; Greenberg, E.; Devir, A.; Yaniv, R.; Bor, J.; Satori, G.

    2006-12-01

    satellite images, it was found that most of the thunderclouds that produced sprites were isolated Cumulonimbus cells embedded within a matrix of lower rain clouds, associated with the cold sector of Cyprus lows. The relationship between the meteorological parameters, storm size, vertical cloud development and lightning properties, as well as a comparison with the properties of thunderstorms producing winter sprites in Japan, will be presented.

  15. An observational study of air and water vapour convergence over the Bernese Alps, Switzerland, during summertime and the development of isolated thunderstorms

    Energy Technology Data Exchange (ETDEWEB)

    Graham, Edward [Bern Univ. (Switzerland). Inst. of Applied Physics; Lews Castle College, University of the Highlands and Islands, Stornoway, Scotland (United Kingdom); N' Dri Koffi, Ernest; Maetzler, Christian [Bern Univ. (Switzerland). Inst. of Applied Physics

    2012-12-15

    The daytime summer phenomenon of the mesoscale transport of air and water vapour from the Swiss lowlands into the nearby western Alps, leading to orographic convection, is investigated using a range of independent observations. These observations are: Global Positioning System (GPS) integrated water vapour (IWV) data, the TROWARA microwave radiometer, MeteoSwiss ANETZ surface weather station data, the Payerne radiosonde, synoptic analyses for Switzerland and Europe, EUMETSAT and NOAA visible and infrared satellite images, MeteoSwiss operational precipitation radar, photographs and webcam images including time-lapse cloud animations. The intention was to show, using GPS IWV data, that significant differences in IWV may occur between the Swiss plain and nearby Alps during small single-cell Alpine thunderstorm events, and that these may be attributable to regional airflow convergence. Two particular case studies are presented for closer examination: 20 June 2005 and 13 June 2006. On both days, fine and warm weather was followed by isolated orographic convection over the Alps in the afternoon and evening, producing thunderstorms. The thunderstorms investigated were generally small, local, discrete and short-lived phenomena. They were selected for study because of almost stationary position over orography, rendering easy observation because they remained contained within a particular mountain region before dissipating. The results show that large transfers of air and water vapour occur from the Swiss plain to the mountains on such days, with up to a 50% increase in GPS IWV values at individual Alpine stations, coincident with strong airflow convergence in the same locality. (orig.)

  16. Thunderstorm nowcasting by means of lightning and radar data: algorithms and applications in northern Italy

    OpenAIRE

    P. Bonelli; P. Marcacci

    2008-01-01

    Thunderstorms and their ground effects, such as flash floods, hail, lightning, strong winds, and tornadoes, are responsible for most weather damages in northern Italy, especially in the warm season from May to September. A nowcasting and warning system focused on severe thunderstorm events would be useful to reduce risks for people involved in outside activities and for electric, telecommunication, and sensitive industrial business. C-band radar and Lighting Location Systems provide useful, f...

  17. Analysis of Thunderstorm (Act Ⅲ)——A Translation by Wang Zuoliang

    Institute of Scientific and Technical Information of China (English)

    康丛凌

    2008-01-01

    @@ Ⅰ. Introduction Thunderstorm written by Cao Yu in 1934 is a masterpiece in the history of Chinese literature. This drama depicts the love and hate between eight people, reflecting a tragic scene of the decline of a rich family in the feudal society. As a splendid treasure of Chinese literature,Thunderstorm was translated into English in 1958 by Wang Zuoliang and A. C. Barnes whose translation is regarded as a great work in the perspective of translating practice.

  18. Analysis of Reynolds stress budgets in LES of Langmuir supercells under crosswind currents in a coastal ocean

    Science.gov (United States)

    Tejada-Martinez, Andres; Zhang, Jie

    2016-11-01

    Langmuir supercells (LSCs) in coastal oceans consist of parallel counter rotating vortices engulfing the water column in unstratified conditions. These cells have been observed in continental shelf regions 15-30 meters deep during the passage of storms. LSCs are aligned roughly in the wind direction and are generated via interaction of the wind-driven shear current and Stokes drift velocity induced by surface gravity waves. LSCs have been determined to be an important contributor to the suspension of sediments and their overall transport across shelves. It has also been shown that tidal forcing distorts and weakens LSCs, inhibiting their potential for sediment suspension. Large-eddy simulations of LSCs in flows driven by a surface wind stress and a constant crosswind pressure gradient (representative of crosswind tidal forcing) have been performed. Although a crosswind tidal current stronger than the wind-driven current is able to break up the LSCs giving rise to smaller scale, weaker Langmuir cells (LCs), analysis of Reynolds shear stress budgets reveals that non-local transport remains significant relative to flow without LCs. This demonstrates the need for a non-local transport term in Reynolds shear stress and turbulent scalar flux closures for coastal flows with LCs. Support from the US National Science Foundation and the Gulf of Mexico Research Initiative is gratefully acknowledged.

  19. A possible explanation for the dominant effect of South American thunderstorms on the Carnegie curve

    Science.gov (United States)

    Kartalev, M. D.; Rycroft, M. J.; Fuellekrug, M.; Papitashvili, V. O.; Keremidarska, V. I.

    2006-02-01

    The Carnegie curve shows the variation of the vertical electric field near the Earth's surface with Universal Time. The largest of the three maxima in this variation occurs at the time of maximum thunderstorm activity over the Americas, although this is weaker than that over Africa. This paradoxical effect may be explained by the fact that South American thunderstorms are close to the magnetic dip equator, whereas most African thunderstorms occur over the Congo at a higher (Southern) dip latitude. Kartalev et al. [2004. A quantitative model of the effect of global thunderstorms on the global distribution of ionospheric electrostatic potential. Journal of Atmospheric and Solar-Terrestrial Physics 66, 1233 1240.] modeled the global distribution of ionospheric electrostatic potential where the equatorial (within 11 magnetic latitude of the equator) lower ionosphere accumulates all upward thunderstorm currents into one line—the dip equator. Currents flow on a spherical shell of the magnetic coordinates model, and so change the distribution of the ionospheric potential on a global scale. That global distribution of ionospheric potential determines the vertical electric field near the Earth's surface everywhere. Thus, the Carnegie curve reflects preferentially the longitudinal distribution of thunderstorms within 11 of the magnetic dip equator.

  20. NOWCASTING OF IN-FLIGHT hazard thunderstorm, supporting aircrew and ATM decision making process

    Science.gov (United States)

    Guillou, Y.; Senesi, S.; Tafferner, A.; Forster, C.

    2009-09-01

    The Integrated Project FLYSAFE allows to define and experiment Weather Information Management Systems (WIMS). These systems provide met data on several weather hazards: icing, clear air turbulence and thunderstorms. The thunderstorm system, called CB WIMS (Cb for Cumulonimbus), has been developed with involvement of partners from Météo-France, German Aerospace Center (DLR), ONERA, UK-Met Office and the University of Hannover. In order to reduce the complexity of a real thunderstorm to a practical model which can be used onboard aircraft for informing pilot of hazard area, it is been represented as bottom and top hazard volumes. The bottom volumes are defined from ground RADAR network and has two levels of hazard severity. The top volume is defined on satellite data and includes only one level of hazard severity. In this presentation, we will focus on test flights operated during summer campaign in August 2008, and more precisely on flights operated by the research plane of Météo-France (ATR42). Through different case studies, we will point out the important contribution of CB WIMS to complete the pilot view of thunderstorm hazards which is available from the single board RADAR. Indeed, in addition to an overview of thunderstorm hazard, the CB WIMS provide relevant information on thunderstorm evolution too. The bottom volume can also indicate hazard area in lower layers not necessary detected by onboard radar but which can result in a moderate turbulence for the plane.

  1. Urban effects and summer thunderstorms in a tropical cyclone affected situation over Guangzhou city

    Institute of Scientific and Technical Information of China (English)

    MENG; WeiGuang; YAN; JingHua; HU; HaiBo

    2007-01-01

    With data mainly from Guangzhou mesonet Automatic Weather Stations (AWS), Guangzhou Doppler Radar and satellite TBB data, characteristics and evolution of the urban heat island (UHI) over Guangzhou City were analyzed in a tropical cyclone affected situation for early August 2005. In particular, two thunderstorms occurring during this period respectively at the night of 4 August and in the afternoon of 7 August were investigated to study the relationships between the development of thunderstorms and the UHI. Results showed that two thunderstorms were associated with the UHI effects. UHI induced local air convergence and initiated the thunderstorm convections. Both cases showed a general agreement in time and space for the locations of maximum UHI, convergence, convection, and precipitation. Convection was found to be more favorable to developing in time periods and locations with stronger intensity of UHI. Analysis also showed that, due to the urban effects, both thunderstorms got strengthened when moving over Guangzhou City, with maximum radar echoes observed right over the urban area and precipitation located within the city. All these features reveal that two thunderstorms were urban-induced storms.

  2. Allergen aerosol from pollen-nucleated precipitation: A novel thunderstorm asthma trigger

    Science.gov (United States)

    Beggs, Paul John

    2017-03-01

    Thunderstorm asthma is the term used to describe epidemics of asthma exacerbation associated with thunderstorms. Most published reports of thunderstorm asthma have come from the United Kingdom, Canada, and Australia, although several studies have been published on the phenomenon in the USA and Europe (particularly Greece and Italy). Such reports usually consider changes in hospital admissions or emergency department attendances for asthma. For example, Celenza et al. (1996) studied an asthma epidemic in London in June 1994 where 40 patients presented to the accident and emergency department of St Mary's Hospital in the 24 hours after a thunderstorm compared to an average of just over 2 asthma presentations per day over the several weeks before and after this event. More recent examples include the 20 patients who presented to an emergency department in Puglia, Italy, for sudden and severe asthmatic symptoms immediately after a thunderstorm in May 2010, where the average daily emergency department presentations for asthma several weeks before and after this event was only 2 to 3 (Losappio et al., 2011); and the 36 emergency department presentations for acute asthma to the Austin Hospital in Melbourne, Australia, on 25 November 2010 immediately after a thunderstorm (with the number of such presentations on days prior to and following the epidemic ranging from 0 to 10) (Howden et al., 2011).

  3. Ionospheric acoustic and gravity wave activity above low-latitude thunderstorms

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-01-30

    In this report, we study the correlation between thunderstorm activity and ionospheric gravity and acoustic waves in the low-latitude ionosphere. We use ionospheric total electron content (TEC) measurements from the Low Latitude Ionospheric Sensor Network (LISN) and lightning measurements from the World- Wide Lightning Location Network (WWLLN). We find that ionospheric acoustic waves show a strong diurnal pattern in summer, peaking in the pre-midnight time period. However, the peak magnitude does not correspond to thunderstorm area, and the peak time is significantly after the peak in thunderstorm activity. Wintertime acoustic wave activity has no discernable pattern in these data. The coverage area of ionospheric gravity waves in the summer was found to increase with increasing thunderstorm activity. Wintertime gravity wave activity has an observable diurnal pattern unrelated to thunderstorm activity. These findings show that while thunderstorms are not the only, or dominant source of ionospheric perturbations at low-latitudes, they do have an observable effect on gravity wave activity and could be influential in acoustic wave activity.

  4. Cloud-resolving chemistry simulation of a Hector thunderstorm

    Directory of Open Access Journals (Sweden)

    K. A. Cummings

    2013-03-01

    Full Text Available Cloud chemistry simulations were performed for a Hector thunderstorm observed on 16 November 2005 during the SCOUT-O3/ACTIVE campaigns based in Darwin, Australia, with the primary objective of estimating the average NO production per lightning flash in this unique storm type which occurred in a tropical island environment. The 3-D WRF-Aqueous Chemistry (WRF-AqChem model is used for these calculations and contains the WRF nonhydrostatic cloud-resolving model with online gas- and aqueous-phase chemistry and a lightning-NOx (LNOx production algorithm. The model was initialized by inducing convection with an idealized morning sounding and sensible heat source, and initial condition chemical profiles from merged aircraft observations in undisturbed air. Many features of the idealized model storm, such as storm size and peak radar reflectivity, were similar to the observed storm. Tracer species, such as CO, used to evaluate convective transport in the simulated storm found vertical motion from the boundary layer to the anvil region was well represented in the model, with a small overestimate of enhanced CO at anvil altitudes. The lightning detection network (LINET provided lightning flash data for the model and a lightning placement scheme injected the resulting NO into the simulated cloud. A lightning NO production scenario of 500 moles flash−1 for both CG and IC flashes yielded anvil NOx mixing ratios that compared well with aircraft observations and were also similar to those deduced for several convective modeling analyses in the midlatitudes and subtropics. However, these NO production values were larger than most estimates for tropical thunderstorms and given several uncertainties, LNOx production may have been as large as 600 moles flash−1. Approximately 85% of the simulated LNOx mass was located above 7 km in the later stages of the storm, which was greater than amounts found for subtropical and midlatitude convection. Modeled upper

  5. The Meteorology of Storms that Produce Narrow Bipolar Events

    Science.gov (United States)

    Lang, Timothy J.; McCaul, Eugene W.; Cummer, Steven A.

    2013-01-01

    Narrow Bipolar Events (NBEs) are compact intracloud discharges that produce the most powerful lightning-related radio frequency signals that have been observed. However, their luminosity is below the threshold for detectability from current and past spaceborne optical sensors. NBEs have been loosely associated with convective intensity, but their occurrence tends to be highly localized in time and space within a thunderstorm, and there remain many questions about whether and to what extent they are significantly related to meteorological processes within thunderstorms. Using the North Alabama Lightning Mapping Array (NALMA), the National Lightning Detection Network, and available Doppler and polarimetric radar data, case studies will be presented for storm events that produced large numbers of NBEs (10s-100s) during their lifetimes. NBEs are documented via a method that identifies high peak power (>40-50 dBW) initial VHF sources within a specific altitude band in the upper levels of thunderstorms. The production of NBEs, including spatial and temporal variability, will be compared to the radar-inferred kinematic and microphysical structure and evolution of thunderstorms, as well as their NALMA- and NLDN-inferred electrical characteristics. The results should provide new insights into the relationships between NBEs and thunderstorm processes.

  6. Alpine debris flows triggered by a 28 July 1999 thunderstorm in the central Front Range, Colorado

    Science.gov (United States)

    Godt, J.W.; Coe, J.A.

    2007-01-01

    On 28 July 1999, about 480 alpine debris flows were triggered by an afternoon thunderstorm along the Continental Divide in Clear Creek and Summit counties in the central Front Range of Colorado. The thunderstorm produced about 43??mm of rain in 4??h, 35??mm of which fell in the first 2??h. Several debris flows triggered by the storm impacted Interstate Highway 70, U.S. Highway 6, and the Arapahoe Basin ski area. We mapped the debris flows from color aerial photography and inspected many of them in the field. Three processes initiated debris flows. The first process initiated 11% of the debris flows and involved the mobilization of shallow landslides in thick, often well vegetated, colluvium. The second process, which was responsible for 79% of the flows, was the transport of material eroded from steep unvegetated hillslopes via a system of coalescing rills. The third, which has been termed the "firehose effect," initiated 10% of the debris flows and occurred where overland flow became concentrated in steep bedrock channels and scoured debris from talus deposits and the heads of debris fans. These three processes initiated high on steep hillsides (> 30??) in catchments with small contributing areas (flow process. Based on field observations and examination of soils mapping of the northern part of the study area, we identified a relation between the degree of soil development and the process type that generated debris flows. In general, areas with greater soil development were less likely to generate runoff and therefore less likely to generate debris flows by the firehose effect or by rilling. The character of the surficial cover and the spatially variable hydrologic response to intense rainfall, rather than a threshold of contributing area and topographic slope, appears to control the initiation process in the high alpine of the Front Range. Because debris flows initiated by rilling and the firehose effect tend to increase in volume as they travel downslope, these

  7. Long-duration gamma-ray emissions from 2007 and 2008 winter thunderstorms

    CERN Document Server

    Tsuchiya, H; Yamada, S; Yuasa, T; Nakazawa, K; Kitaguchi, T; Kawaharada, M; Kokubun, M; Kato, H; Okano, M; Makishima, K

    2011-01-01

    The Gamma-Ray Observation of Winter THunderclouds (GROWTH) experiment, consisting of two radiation-detection subsystems, has been operating since 2006 on the premises of Kashiwazaki-Kariwa nuclear power plant located at the coastal area of Japan Sea. By 2010 February, GROWTH detected 7 long-duration $\\gamma$-rays emissions associated with winter thunderstorms. Of them, two events, obtained on 2007 December 13 and 2008 December 25, are reported.On both occasions, all inorganic scintillators (NaI, CsI, and BGO) of the two subsystems detected significant gamma-ray signals lasting for >1 minute. Neither of these two events were associated with any lightning. In both cases, the gamma-ray energy spectra extend to 10 MeV, suggesting that the detected gamma-rays are produced by relativistic electrons via bremsstrahlung. Assuming that the initial photon spectrum at the source is expressed by a power-law function,the observed photons can be interpreted as being radiated from a source located at a distance of 290-560 m ...

  8. Relativistic electron avalanches as a thunderstorm discharge competing with lightning.

    Science.gov (United States)

    Kelley, Nicole A; Smith, David M; Dwyer, Joseph R; Splitt, Michael; Lazarus, Steven; Martinez-McKinney, Forest; Hazelton, Bryna; Grefenstette, Brian; Lowell, Alexander; Rassoul, Hamid K

    2015-08-12

    Gamma-ray 'glows' are long duration (seconds to tens of minutes) X-ray and gamma-ray emission coming from thunderclouds. Measurements suggest the presence of relativistic runaway electron avalanches (RREA), the same process underlying terrestrial gamma-ray flashes. Here we demonstrate that glows are relatively a common phenomena near the tops of thunderstorms, when compared with events such as terrestrial gamma-ray flashes. Examining the strongest glow measured by the airborne detector for energetic emissions, we show that this glow is measured near the end of a downward RREA, consistent with occurring between the upper positive charge layer and the negative screening layer above it. The glow discharges the upper positive layer by ≥9.6 mA, strong enough to be an important charging mechanism of the storm. For this glow, the gamma-ray flux observed is close to the value at which relativistic feedback processes become important, with an avalanche multiplication factor of 4,500.

  9. Thunderstorm Observations by Air-Shower Radio Antenna Arrays

    CERN Document Server

    Apel, W D; Bähren, L; Bekk, K; Bertaina, M; Biermann, P L; Blümer, J; Bozdog, H; Brancus, I M; Buchholz, P; Buitink, S; Cantoni, E; Chiavassa, A; Daumiller, K; de Souza, V; Doll, P; Ender, M; Engel, R; Falcke, H; Finger, M; Fuhrmann, D; Gemmeke, H; Grupen, C; Haungs, A; Heck, D; Hörandel, J R; Horneffer, A; Huber, D; Huege, T; Isar, P G; Kampert, K -H; Kang, D; Krömer, O; Kuijpers, J; Link, K; Luczak, P; Ludwig, M; Mathes, H J; Melissas, M; Morello, C; Nehls, S; Oehlschläger, J; Palmieri, N; Pierog, T; Rautenberg, J; Rebel, H; Roth, M; Rühle, C; Saftoiu, A; Schieler, H; Schmidt, A; Schröder, F G; Sima, O; Toma, G; Trinchero, G C; Weindl, A; Wochele, J; Wommer, M; Zabierowski, J; Zensus, J A; 10.1016/j.asr.2011.06.003

    2013-01-01

    Relativistic, charged particles present in extensive air showers lead to a coherent emission of radio pulses which are measured to identify the shower initiating high-energy cosmic rays. Especially during thunderstorms, there are additional strong electric fields in the atmosphere, which can lead to further multiplication and acceleration of the charged particles and thus have influence on the form and strength of the radio emission. For a reliable energy reconstruction of the primary cosmic ray by means of the measured radio signal it is very important to understand how electric fields affect the radio emission. In addition, lightning strikes are a prominent source of broadband radio emissions that are visible over very long distances. This, on the one hand, causes difficulties in the detection of the much lower signal of the air shower. On the other hand the recorded signals can be used to study features of the lightning development. The detection of cosmic rays via the radio emission and the influence of s...

  10. Initial Electric Field Changes of Lightning Flashes in Two Thunderstorms

    Science.gov (United States)

    Marshall, T. C.; Stolzenburg, M.; Karunarathne, S.; Chapman, R.

    2015-12-01

    In a study of lightning initiation, Marshall et al. [2014, JGR Atmospheres] found that an initial electric field change (IEC) occurred before the initial breakdown (IB) pulses in 18 cloud-to-ground (CG) flashes and in 18 intracloud (IC) flashes. Because the IECs were small in amplitude and slowly developing (i.e., primarily electrostatic events), they were only detected by sensors within the reversal distance of each flash. In this presentation we report on a search for IECs in two small Florida thunderstorms that occurred close to several E-change sensors. One storm had 57 flashes; the other had only 13 flashes. The key result is that 69 of the 70 flashes began with detectable IECs. For the one flash without a detectable IEC, the closest sensor was at the reversal distance, presumably masking the IEC. Three of the flashes analyzed seemed to begin twice, in the sense that they had two sets of IB pulses; each beginning was preceded by an IEC.

  11. High energy radiation from aircraft-triggered lightning and thunderstorm

    Science.gov (United States)

    Kochkin, Pavlo; van Deursen, Alexander P. J.; de Boer, Alte I.; Bardet, Michiel; Boissin, Jean-François

    2016-04-01

    In-flight Lightning Strike Damage Assessment System (ILDAS http://ildas.nlr.nl/) was developed in an EU FP6 project to provide information on threat that lightning poses to aircraft. The system contains one E-field and eight H-field sensors distributed over the fuselage. It has recently been extended to include two LaBr3 scintillation detectors. The scintillation detectors are sensitive to x-ray photons above 30 keV. The entire system is installed on an A-350 aircraft. When triggered by lightning and digitizes data synchronously with 10 ns intervals. Twelve continuously monitoring photon energy channels were implemented for X-ray detectors operating at slower rate (15 ms, pulse counting). In spring of 2014 and 2015 the aircraft flew through thunderstorm cells recording the data from the sensors. Total of 93 lightning strikes to the aircraft are recorded. Eighteen of them are also detected by WWLLN network. One strike consists of six individual strokes within 200 ms that were all synchronously identified by WWLLN. The WWLLN inter-stroke distance is much larger than the aircraft movement. Three of these strokes generated X-ray bursts. One exceptionally bright X-ray pulse of more than 8 MeV has been detected in association with another strike; it probably saturated the detector's photomultiplier. Neither long gamma-ray glow, nor positron annihilation have been detected during the campaign. An explanation is sought in the typical altitude profile of these test flights.

  12. A numerical study of aerosol effects on electrification of thunderstorms

    Science.gov (United States)

    Tan, Y. B.; Shi, Z.; Chen, Z. L.; Peng, L.; Yang, Y.; Guo, X. F.; Chen, H. R.

    2017-02-01

    Numerical simulations are performed to investigate the effect of aerosol on microphysical and electrification in thunderstorm clouds. A two-dimensional (2-D) cumulus model with electrification scheme including non-inductive and inductive charge separation is used. The concentration of aerosol particles with distribution fitted by superimposing three log-normal distributions rises from 50 to 10,000 cm-3. The results show that the response of charge separation rate to the increase of aerosol concentration is nonmonotonic. When aerosol concentration is changed from 50 to 1000 cm-3, a stronger formation of cloud droplet, graupel and ice crystal results in increasing charge separation via non-inductive and inductive mechanism. However, in the range of 1000-3000 cm-3, vapor competition arises in the decrease of ice crystal mixing ratio and the reduction of ice crystals size leads to a slightly decrease in non-inductive charge rate, while inductive charging rate has no significant change in magnitude. Above aerosol concentration of 3000 cm-3, the magnitude of charging rate which keeps steady is insensitive to the increase in aerosol concentration. The results also suggest that non-inductive charge separation between ice crystal and graupel contributes to the main upper positive charge region and the middle negative charge region. Inductive graupel-cloud droplet charge separation, on the other hand, is found to play an important role in the development of lower charge region.

  13. The challenge of predicting flash floods from thunderstorm rainfall.

    Science.gov (United States)

    Gupta, Hosin; Sorooshian, Soroosh; Gao, Xiaogang; Imam, Bisher; Hsu, Kuo-Lin; Bastidas, Luis; Li, Jailun; Mahani, Shayesteh

    2002-07-15

    A major characteristic of the hydrometeorology of semi-arid regions is the occurrence of intense thunderstorms that develop very rapidly and cause severe flooding. In summer, monsoon air mass is often of subtropical origin and is characterized by convective instability. The existing observational network has major deficiencies for those regions in providing information that is important to run-off generation. Further, because of the complex interactions between the land surface and the atmosphere, mesoscale atmospheric models are currently able to reproduce only general features of the initiation and development of convective systems. In our research, several interrelated components including the use of satellite data to monitor precipitation, data assimilation of a mesoscale regional atmospheric model, modification of the land component of the mesoscale model to better represent the semi-arid region surface processes that control run-off generation, and the use of ensemble forecasting techniques to improve forecasts of precipitation and run-off potential are investigated. This presentation discusses our ongoing research in this area; preliminary results including an investigation related to the unprecedented flash floods that occurred across the Las Vegas valley (Nevada, USA) in July of 1999 are discussed.

  14. The diagnosis of severe thunderstorms with high-resolution WRF model

    Indian Academy of Sciences (India)

    A J Litta; U C Mohanty; Sumam Mary Idicula

    2012-04-01

    Thunderstorm, resulting from vigorous convective activity, is one of the most spectacular weather phenomena in the atmosphere. A common feature of the weather during the pre-monsoon season over the Indo-Gangetic Plain and northeast India is the outburst of severe local convective storms, commonly known as ‘Nor’westers’(as they move from northwest to southeast). The severe thunderstorms associated with thunder, squall lines, lightning and hail cause extensive losses in agricultural, damage to structure and also loss of life. In this paper, sensitivity experiments have been conducted with the Non-hydrostatic Mesoscale Model (NMM) to test the impact of three microphysical schemes in capturing the severe thunderstorm event occurred over Kolkata on 15 May 2009. The results show that the WRF-NMM model with Ferrier microphysical scheme appears to reproduce the cloud and precipitation processes more realistically than other schemes. Also, we have made an attempt to diagnose four severe thunderstorms that occurred during pre-monsoon seasons of 2006, 2007 and 2008 through the simulated radar reflectivity fields from NMM model with Ferrier microphysics scheme and validated the model results with Kolkata Doppler Weather Radar (DWR) observations. Composite radar reflectivity simulated by WRF-NMM model clearly shows the severe thunderstorm movement as observed by DWR imageries, but failed to capture the intensity as in observations. The results of these analyses demonstrated the capability of high resolution WRF-NMM model in the simulation of severe thunderstorm events and determined that the 3 km model improve upon current abilities when it comes to simulating severe thunderstorms over east Indian region.

  15. Lightning characteristics relative to radar, altitude and temperature for a multicell, MCS and supercell over northern Alabama

    Science.gov (United States)

    Mecikalski, Retha M.; Carey, Lawrence D.

    2017-07-01

    Cloud electrification leads to the production of nitrogen oxides (NOx), which has an effect on ozone concentrations. Currently large uncertainties exist regarding the contribution of lightning to the global and local NOx budget, even on a per flash basis. Most lightning NOx (LNOx) models distribute the LNOx at reflectivities (Z) ≥ 20 dBZ in the horizontal, while vertically, a Gaussian distribution function with a peak at - 15 °C is used for cloud-to-ground (CG) flashes and a bimodal distribution function with peaks at - 15 °C and - 45 °C is used for inter- and intra-cloud (IC) flashes. This research aims to improve our basic understanding of lightning location relative to radar Z as a function of storm and flash type. Using data from the North Alabama Lightning Mapping Array (NALMA) and the Multi-Radar Multi-Sensor data suite, the results from analyzing a multicell storm, mesoscale convective system and supercell storm showed that 29.7%, 15.9% and 6.9% of all flashes initiated in regions where Z lightning initiation distribution for IC flashes was also not observed for any of the three storms. In addition, it is shown that when incorporating the propagation of the flash, the percentage of NALMA lightning sources located in regions where Z < 20 dBZ increases. Finally, when comparing flash types, the results show that Hybrid flashes have consistently larger sizes than IC and CG flashes, while IC and Hybrid flashes tend to have more sources located at Z < 20 dBZ than CG flashes.

  16. Cb-LIKE - Thunderstorm forecasts up to six hours with fuzzy logic

    Science.gov (United States)

    Köhler, Martin; Tafferner, Arnold

    2016-04-01

    Thunderstorms with their accompanying effects like heavy rain, hail, or downdrafts cause delays and flight cancellations and therefore high additional cost for airlines and airport operators. A reliable thunderstorm forecast up to several hours could provide more time for decision makers in air traffic for an appropriate reaction on possible storm cells and initiation of adequate counteractions. To provide the required forecasts Cb-LIKE (Cumulonimbus-LIKElihood) has been developed at the DLR (Deutsches Zentrum für Luft- und Raumfahrt) Institute of Atmospheric Physics. The new algorithm is an automated system which designates areas with possible thunderstorm development by using model data of the COSMO-DE weather model, which is driven by the German Meteorological Service (DWD). A newly developed "Best-Member- Selection" method allows the automatic selection of that particular model run of a time-lagged COSMO- DE model ensemble, which matches best the current thunderstorm situation. Thereby the application of the best available data basis for the calculation of the thunderstorm forecasts by Cb-LIKE is ensured. Altogether there are four different modes for the selection of the best member. Four atmospheric parameters (CAPE, vertical wind velocity, radar reflectivity and cloud top temperature) of the model output are used within the algorithm. A newly developed fuzzy logic system enables the subsequent combination of the model parameters and the calculation of a thunderstorm indicator within a value range of 12 up to 88 for each grid point of the model domain for the following six hours in one hour intervals. The higher the indicator value the more the model parameters imply the development of thunderstorms. The quality of the Cb-LIKE thunderstorm forecasts was evaluated by a substantial verification using a neighborhood verification approach and multi-event contingency tables. The verification was performed for the whole summer period of 2012. On the basis of a

  17. Early detection of severe thunderstorms in the Alpine region: the dynamical approach of COALITION.

    Science.gov (United States)

    Nisi, L.; Giunta, I.; Ambrosetti, P.; Clementi, L.

    2010-09-01

    The basic physical mechanisms governing thunderstorms are fairly well understood and these rely on the analysis of temperature and humidity profiles at upper and lower layers. Furthermore, the topography, particularly important in the Alpine region, specifically drives the conditions at boundary layer, where convection elements can be initiated, focused, oriented, reactivated or inhibited. The accurate observation of specific features, e.g. retrieved by remote sensing methods, and appearing at different phases of the thunderstorm lifecycle (pre-convective, convective, deep, mature stage), can lead to significant improvements of the forecast-skills. The challenge is how to build up a methodology for integrating physical and heuristic information into one appropriate, consistent Nowcasting model for complex terrains. The here presented heuristic model (Context and Scale Oriented Thunderstorm Satellite Predictors Development - COALITION) collects and assimilates the information from different data sources and applications (e.g. Meteosat Second Generation, MetOp/IASI, Weather Radar, Numerical Weather Prediction, Topography) into a simplified model, where thunderstorm predictors (e.g. instability indices, moisture convergence) are merged with evolving thunderstorm properties. The storm evolution results then as solution of particular motion equations, governed by couplings between convective signatures (objects) and environments (pseudo potential fields). The improved time-linkage between different features and phases, will be basis for the early prediction of the storm.

  18. Thunderstorm-Associated Asthma or Shortness of Breath Epidemic: A Canadian Case Report

    Directory of Open Access Journals (Sweden)

    AE Dennis Wardman

    2002-01-01

    Full Text Available Thunderstorm-associated asthma epidemics have been documented in the literature, but no Canadian experience has been reported. On July 31, 2000, a thunderstorm-associated epidemic of asthma or shortness of breath occurred in Calgary, Alberta. The Calgary Health Region investigated the event using diagnostic data from emergency departments, an urgent care medical clinic and patient interviews, in addition to bioaerosol counts, pollutant data and weather data reflecting atmospheric conditions at that time. On July 31, 2000 and August 1, 2000, 157 people sought care for asthma symptoms. The expected number of people to seek care for such symptoms in a 48 h period in Calgary is 17. Individuals with a personal or family history of asthma, allergies or hay fever who were not taking regular medication for these conditions and who were outdoors before the storm appeared to have been preferentially affected. A stagnant air mass the day before the thunderstorm may have resulted in declining bioaerosol concentrations, and the possible accumulation of spore and pollen reservoirs within mould and plant structures. The elevated bioaerosol concentrations observed on the day of the thunderstorm may be attributed to the sudden onset of high winds during the thunderstorm, which triggered a sudden release of spores and pollens into the atmosphere, which was probably responsible for the epidemic. Several pollutant levels slightly increased on the day of the storm and possibly also played a role in symptom development. It is unclear whether an atmospheric pressure drop contributed to the release of spores and pollens.

  19. 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.

  20. 2010年后汛期一次东风波雷雨大风天气分析%Analysis on an Easterly Wave Thunderstorm and Gale Weather in Latter Flood Season of 2010

    Institute of Scientific and Technical Information of China (English)

    何云燕; 林确略; 杨礼林; 刘金裕; 甘桂华

    2012-01-01

    thunderstorm and gale weather happened, the position of subtropical high was by north (the ridge line was at 35° N). The eastward movement of north branch of trough compelled subtropical high splitting into east and west circulation. The westward extension of east subtropical high and saddle-type filed circulation were favorable for generation and development of easterly wave. As the development and westward movement of easterly wave, in the influence zone in front of trough, the upper easterly component transmitted downward. Then, the low-level north-' easter obviously strengthened, and the thunderstorm and gale weather appeared. In the zone where the thunderstorm and gale happened, the airflow at middle and low layers had cyclonic convergence, and had anti-cyclonic divergence near ground layer. The subsidence movement was obvious. Moreover, the thermal structure that it tended to be dry and cold at middle and high layers, warm and wet at low layer existed. The supercell storm was at developed stage on 4th. It had obvious meso-cyclone and hooked echo characteristics ( meso-and small-scale characteris-tics ). The characteristics of squall line, gale region and adverse wind region appeared in central west Guangdong on 5th. Doppler characteristics of meso-cyclone, hooked echo, squall line, gale region and adverse wind region had indication significance for the short-imminent forecast of thunderstorm and gale. [ Conclusion ] The research revealed some information which had significance for forecasting local easterly wave thunderstorm and gale weather.

  1. Initial electric field changes of lightning flashes in two thunderstorms

    Science.gov (United States)

    Chapman, Ryan; Marshall, Thomas; Karunarathne, Sumedhe; Stolzenburg, Maribeth

    2017-04-01

    The beginning of all 75 lightning flashes in two small thunderstorms was investigated using an array of electric field change (E-change) meters and an array of VHF sensors with the goal of determining if an initial E-change (IEC) preceded the initial breakdown (IB) pulses in each flash. IECs were found at the beginning of all 62 flashes in Storm 1 and all 13 flashes in Storm 2. Hence, it is concluded that an IEC is a fundamental part of most or all lightning initiations and that an IEC is needed prior to the first IB pulse in a flash. IEC durations averaged 0.23 ms for cloud-to-ground (CG) flashes (range 0.08-0.54 ms) and averaged 2.7 ms for normal intracloud (IC) flashes (range 0.04-9.8 ms). IEC point dipole moments averaged 26 C m for CG flashes (range 4-86 C m) and averaged -140 C m for normal IC flashes (range -8 to -650 C m). IEC current moments averaged 120 kA m for CG flashes (range 41-410 kA m) and averaged -91 kA m for normal IC flashes (range -2 to -630 kA m). E-change data support the suggestion that weak narrow bipolar event type events initiate some lightning flashes, but 41 of the 75 flashes had no detectable initiating pulse > 0.04 V m-1 range normalized to 100 km. Two flashes had two IECs; the second IEC of each flash initiated a new lightning channel that propagated in a new direction and at a higher altitude than the original development after the first IEC.

  2. The Anthropogenic/Lightning Effects Around Houston: The Houston Environmental Aerosol Thunderstorm (HEAT) Project - 2005

    Science.gov (United States)

    Orville, R. E.

    2004-12-01

    A major field program will occur in summer 2005 to determine the sources and causes for the enhanced cloud-to-ground lightning over Houston, Texas. This program will be in association with simultaneous experiments supported by the Environmental Protection Agency (EPA) and the Texas Commission on Environmental Quality (TCEQ), formally the Texas Natural Resource Conservation Commission (TNRCC). Recent studies covering the period 1989-2002 document a 60 percent increase of cloud-to-ground lightning in the Houston area as compared to surrounding background values, which is second in flash density only to the Tampa Bay, Florida area. We suggest that the elevated flash densities could result from several factors, including 1) the convergence due to the urban heat island effect and complex sea breeze (thermal hypothesis), and 2) the increasing levels of air pollution from anthropogenic sources producing numerous small cloud droplets and thereby suppressing mean droplet size (aerosol hypothesis). The latter effect would enable more cloud water to reach the mixed phase region where it is involved in the formation of precipitation and the separation of electric charge, leading to an enhancement of lightning. The primary goals of HEAT are to examine the effects of (1) pollution, (2) the urban heat island, and (3) the complex coastline on storms and lightning characteristics in the Houston area. The transport of air pollutants by Houston thunderstorms will be investigated. In particular, the relative amounts of lightning-produced and convectively transported NOx into the upper troposphere will be determined, and a comparison of the different NOx sources in the urban area of Houston will be developed. The HEAT project is based on the observation that there is an enhancement in cloud-to-ground (CG) lightning. Total lightning (intracloud (IC) and CG) will be measured using a lightning mapping system (LDAR II) to observe if there is an enhancement in intracloud lightning as well.

  3. Corona discharges from a windmill and its lightning protection tower in winter thunderstorms

    Science.gov (United States)

    Wu, Ting; Wang, Daohong; Rison, William; Thomas, Ronald J.; Edens, Harald E.; Takagi, Nobuyuki; Krehbiel, Paul R.

    2017-05-01

    This paper presents lightning mapping array (LMA) observations of corona discharges from a windmill and its lightning protection tower in winter thunderstorms in Japan. Corona discharges from the windmill, called windmill coronas, and those from the tower, called tower coronas, are distinctly different. Windmill coronas occur with periodic bursts, generally radiate larger power, and possibly develop to higher altitudes than tower coronas do. A strong negative electric field is necessary for the frequent production of tower coronas but is not apparently related with windmill coronas. These differences are due to the periodic rotation of the windmill and the moving blades which can escape space charges produced by corona discharges and sustain a large local electric field. The production period of windmill coronas is related with the rotation period of the windmill. Surprisingly, for one rotation of the windmill, only two out of the three blades produce detectable discharges and source powers of discharges from these two blades are different. The reason for this phenomenon is still unclear. For tower coronas, the source rate can get very high only when there is a strong negative electric field, and the source power can get very high only when the source rate is very low. The relationship between corona discharges and lightning flashes is investigated. There is no direct evidence that corona discharges can increase the chance of upward leader initiation, but nearby lightning flashes can increase the source rate of corona discharges right after the flashes. The peak of the source height distribution of corona discharges is about 100 m higher than the top of the windmill and the top of the tower. Possible reasons for this result are discussed.

  4. Extreme rainfall and debris flows from an orographic thunderstorm in the Eastern Italian Alps

    Science.gov (United States)

    Tarolli, Paolo; Marra, Francesco; Penna, Daniele; Nikolopoulos, Efthymios I.

    2013-04-01

    The upper Adige river basin, in Northern Italy, occupy a distinctive hydrometeorological niche, characterised by high frequency of orographic thunderstorms. Relatively small-extent flash floods and debris flows are triggered by these storm events. The hydrometeorological and hydrological controls of these events are examined through analyses of a storm system occurred on August 1, 2005 on the Rio Gola river basin (6.59 km2, Eastern Italian Alps, Adige river basin). The intense orographic convective system produced locally extreme rainfall peaks in 1.5 hours. The storm concentrated on small, rocky and steeply sloping basin where concentrated overland flow feeds ephemeral channels incised in slope deposits. Despite the short duration of the event the storm triggered an unusually large debris flow, with a volume of about 100,000 m3, producing significant geomorphological impacts and abrupt changes in the extent of incision and channel widening. Hydrometeorological analyses of the storm are based on radar reflectivity observations, raingauge and streamgauge data. The orographic organization of the precipitation system is examined by means of the hypsometric rainfall moments. Detailed geomorphological field surveys, rainfall estimates from radar observations, and the application of a distributed hydrological model in comparison with observed discharge, served as the basis to evaluate erosion processes and quantify the water runoff production at the initiation debris flow area. The hydrological analysis is used to evaluate the consistency among the different observations and to identify the critical factors controlling the debris flow triggering. The hydrological analysis shows that the critical factor is storm concentration on rocky and steeply surfaces and formation of concentrated surface flow at the bottom of channels filled by coarse loose debris.

  5. In situ measurements of contributions to the global electrical circuit by a thunderstorm in southeastern Brazil

    Science.gov (United States)

    Thomas, J.N.; Holzworth, R.H.; McCarthy, M.P.

    2009-01-01

    The global electrical circuit, which maintains a potential of about 280??kV between the earth and the ionosphere, is thought to be driven mainly by thunderstorms and lightning. However, very few in situ measurements of electrical current above thunderstorms have been successfully obtained. In this paper, we present dc to very low frequency electric fields and atmospheric conductivity measured in the stratosphere (30-35??km altitude) above an active thunderstorm in southeastern Brazil. From these measurements, we estimate the mean quasi-static conduction current during the storm period to be 2.5 ?? 1.25??A. Additionally, we examine the transient conduction currents following a large positive cloud-to-ground (+ CG) lightning flash and typical - CG flashes. We find that the majority of the total current is attributed to the quasi-static thundercloud charge, rather than lightning, which supports the classical Wilson model for the global electrical circuit.

  6. Solar terrestrial relationships related to thunderstorms and BUV dark current and ozone data

    Science.gov (United States)

    Herman, J. R.

    1980-01-01

    Solar terrestrial interactions as they affect Nimbus 4 BUV dark current and possibly affect thunderstorm occurrence are investigated. A solar wind index is calculated for 1970 to 1971. Dark current enhancements appear to be associated in some way with solar proton events and the solar wind index, but additional investigations by GSFC are required before conclusions can be drawn. Superposed epoch analysis of an index of North American thunderstorm occurrence reveals a discernible increase in the index magnitude on days 1 and 2 following solar proton events. There appears to be little or no 27 day recurrence tendency in thunderstorm occurrence frequency and no association with vorticity area index on a day to day basis.

  7. Recovery curves of the lightning discharges occurring in the dissipation stage of thunderstorms

    Indian Academy of Sciences (India)

    S D Pawar; A K Kamra

    2013-04-01

    Measurements of atmospheric electric field made below two thunderstorms show that all lightning discharges occurring in the dissipating stage of a thunderstorm occur at almost the same value of the predischarge electric field at the ground surface. The observation is explained on the basis of the shielding of the electric fields generated by the positive charge in the downdrafts by the negative charge in the screening layers formed around them in the subcloud layer. Our observations suggest that in the dissipating stage of the thunderstorm, the charge generating mechanisms in cloud have ceased to operate and the charge being transported from the upper to lower regions of cloud by downdrafts is the only in-cloud process affecting the surface electric field and/or enhancing the electric field stress in and below the cloud base to cause yet another lightning discharge.

  8. Variation of the low level winds during the passage of a thunderstorm gust front

    Science.gov (United States)

    Sinclair, R. W.; Anthes, R. A.; Panofsky, H. A.

    1973-01-01

    Three time histories of wind profiles in thunderstorm gust fronts at Cape Kennedy and three at Oklahoma City are analyzed. Wind profiles at maximum wind strength below 100 m follow logarithmic laws, so that winds above the surface layer can be estimated from surface winds once the roughness length is known. A statistical analysis of 81 cases of surface winds during thunderstorms at Tampa revealed no predictor with skill to predict the time of maximum gust. Some 34% of the variance of the strength of the gust is accounted for by a stability index and surface wind prior to the gust; the regression equations for these variables are given. The coherence between microscale wind speed variations at the different levels has the same proportions as in non-thunderstorm cases.

  9. Analysis on an Easterly Wave Thunderstorm and Gale Weather during the Latter Flood Season of 2010

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    [Objective] The research aimed to analyze an easterly wave thunderstorm and gale weather during the latter flood season of 2010.[Method] Based on conventional observation data,data of automatic station,NCEP 1°×1° reanalysis data,Doppler radar reflectivity and radial velocity data,the easterly wave thunderstorm and gale weather process which happened during 4-5 August,2010 was analyzed.The circulation situation,wind field and dynamic & thermal structures of easterly wave,echo characteristics of Doppler radar...

  10. Cloud-resolving simulations of mercury scavenging and deposition in thunderstorms

    Directory of Open Access Journals (Sweden)

    U. S. Nair

    2013-02-01

    Full Text Available This study examines dynamical and microphysical features of convective clouds that affect mercury (Hg wet scavenging and concentrations in rainfall. Using idealized numerical model simulations in the Regional Atmospheric Modeling System (RAMS, we diagnose vertical transport and scavenging of soluble Hg species in thunderstorms under typical environmental conditions found in the Northeast and Southeast United States (US. Three important environmental characteristics that impact thunderstorm morphology were studied: convective available potential energy (CAPE, vertical shear (0���6 km of horizontal wind (SHEAR and precipitable water (PW.

    We find that in a strong convective storm in the Southeast US that about 40% of mercury in the boundary layer (0–2 km can be scavenged and deposited to the surface. Removal efficiencies are 35% or less in the free troposphere and decline with altitude. Nevertheless, if we assume that soluble Hg species are initially uniformly mixed vertically, then about 60% deposited mercury deposited by the thunderstorm originates in the free troposphere.

    For a given CAPE, storm morphology and Hg deposition respond to SHEAR and PW. Experiments show that the response of mercury concentration in rainfall to SHEAR depends on the amount of PW. For low PW, increasing SHEAR decreases mercury concentrations in high-rain amounts (>13 mm. However, at higher PW values, increasing SHEAR decreases mercury concentrations for all rainfall amounts. These experiments suggest that variations in environmental characteristics relevant to thunderstorm formation and evolution can also contribute to geographical difference in wet deposition of mercury.

    An ensemble of thunderstorm simulations was also conducted for different combinations of CAPE, SHEAR and PW values derived from radiosonde observations at five sites in the Northeast United States (US and at three sites in the Southeast US. Using identical initial

  11. Cloud-resolving chemistry simulation of a Hector thunderstorm

    Directory of Open Access Journals (Sweden)

    K. A. Cummings

    2012-07-01

    Full Text Available Cloud chemistry simulations are performed for a Hector storm observed on 16 November 2005 during the SCOUT-O3/ACTIVE campaigns based in Darwin, Australia, with the primary objective of estimating the average production of NO per lightning flash during the storm which occurred in a tropical environment. The 3-D WRF-AqChem model (Barth et al., 2007a containing the WRF nonhydrostatic cloud-resolving model, online gas- and aqueous-phase chemistry, and a lightning-NOx production algorithm is used for these calculations. An idealized early morning sounding of temperature, water vapor, and winds is used to initialize the model. Surface heating of the Tiwi Islands is simulated in the model to induce convection. Aircraft observations from air undisturbed by the storm are used to construct composite initial condition chemical profiles. The idealized model storm has many characteristics similar to the observed storm. Convective transport in the idealized simulated storm is evaluated using tracer species, such as CO and O3. The convective transport of CO from the boundary layer to the anvil region was well represented in the model, with a small overestimate of the increase of CO at anvil altitudes. Lightning flashes observed by the LIghtning detection NETwork (LINET are input to the model and a lightning placement scheme is used to inject the resulting NO into the simulated cloud. We find that a lightning NO production scenario of 500 moles per flash for both CG and IC flashes yields anvil NOx mixing ratios that match aircraft observations well for this storm. These values of NO production nearly match the mean values for CG and IC flashes obtained from similar modeling analyses conducted for several midlatitude and subtropical convective events and are larger than most other estimates for tropical thunderstorms. Approximately 85% of the lightning NOx mass was located at altitudes greater than 7 km in the later

  12. 2010年3月5日闽北经典超级单体风暴天气过程分析%Analysis on Weather Process of Classic Supercell Storm in Northern Part of Fujian on 5 March 2010

    Institute of Scientific and Technical Information of China (English)

    吴木贵; 张信华; 傅伟辉; 赖荣钦; 冯晋勤

    2013-01-01

    峰机理进行了讨论.%A severe convective weather occurred in northern Fujian from 16 :20 to 19 :50 on 5 March 2010 was mainly caused by three local severe storms in mesoscale convective echo group. The strongest cell of three local server stroms was a classic(CL) supercell storm, which produced sever hail in 220 km along the way. Using radar data of Jianyang CINRAD/SA, routine upper-air and surface observation data, the CL supercell's evolving feature and environmental conditions were analyzed. The main results are as follows: (l)The storm appeared in a mesoscale low pressure which had the characteristic of the terrain occlusion in surface. The low pressure was in the front of the upper-troposphere trough, under the southwest middle-level jet, on the south side of shear-line and frontal zone on 850 hPa and in the front of low-level jet; the storm was produced from the cold front which located on the west of the low pressure, then the storm moved along the concentrated line in surface and passed through the center of the low pressure, at last the storm reached cold zone of stationary front which located on the east of the low pressure and quickly weakened then. The storm always maintained the relative isolated state and life-history was 4 h 52 min, the storm's average speed was 75 km · h-1 and the storm was a high centroid convective system. (2) During the mature stage (15:57 - 18:47) the storm maintained the classic supercell characteristics of the moderate intensity or more mesocyclone, the correlative bounded weak echo regions (BWER), lower-level hook-echo and other features. Moreover it come through three times peak development ( 16 : 03 - 16 : 34 , 16:52 - 17:17, 17:41 - 18:47, respectively); correspondingly, the mesocyclone of the storm enhanced and stretched to the ground in the peak period. In the second peak period, the storm appeared the phenomenon of declining of echo-overhang, updating lower level hook-echo and disappearing of BWER, these evolving

  13. A study of the contribution of thunderstorms to the Global Electric Circuit using a time dependent numerical model and a fractal model

    Science.gov (United States)

    Mallios, Sotirios A.

    on the overall current system. We extend the model to include the whole domain of the GEC. We investigate different types of boundary conditions for the proper modeling of the global current flow in the presence of a single storm and the resulting potential difference that is created. We compare this model in the steady state limit with a static model that has been developed in previous published studies. We apply the model to a case of an experimentally measured thunderstorm. We investigate the Wilson current that flows from its top towards the ionosphere as a function of a sequence of different types of lightning discharges, the flash rate and the conductivity distribution. We compare the results with the measurements and we make conclusions regarding the validity of the modeling concept. We develop a time-dependent fluid model that is able to calculate self consistently the time dynamics of the conductivity distribution along with the time dynamics of the thunderstorm electrical properties. This model takes into account several atmospheric processes such as the ionization due to the galactic cosmic rays radiation, the ion-ion recombination, and the attachment of ions to cloud particles. We study the regimes at which the previous models that assume constant conductivity over time are valid and we quantify the similarities and differences between these two models. Finally, we model the lightning discharge channel using a three-dimensional cartesian fractal model. The purpose of this model is to simulate several types of lightning discharges that occur in realistic thunderstorms and calculate the amount of charge that is removed or neutralized from each thunderstorm. At the same time we used this model to quantify the potential differences produced in a developing IC lightning discharge for given thunderstorm electric configurations. We present a case of a +IC lightning discharge in a realistic thunderstorm configuration that leads to a very high (˜300 MV) potential

  14. An observational study of air and water vapour convergence over the Bernese Alps, Switzerland, during summertime and the development of isolated thunderstorms

    Directory of Open Access Journals (Sweden)

    Edward Graham

    2012-12-01

    Full Text Available The daytime summer phenomenon of the mesoscale transport of air and water vapour from the Swiss lowlands into the nearby western Alps, leading to orographic convection, is investigated using a range of independent observations. These observations are: Global Positioning System (GPS integrated water vapour (IWV data, the TROWARA microwave radiometer, MeteoSwiss ANETZ surface weather station data, the Payerne radiosonde, synoptic analyses for Switzerland and Europe, EUMETSAT and NOAA visible and infra-red satellite images, MeteoSwiss operational precipitation radar, photographs and webcam images including time-lapse cloud animations. The intention was to show, using GPS IWV data, that significant differences in IWV may occur between the Swiss plain and nearby Alps during small single-cell Alpine thunderstorm events, and that these may be attributable to regional airflow convergence. Two particular case studies are presented for closer examination: 20 June 2005 and 13 June 2006. On both days, fine and warm weather was followed by isolated orographic convection over the Alps in the afternoon and evening, producing thunderstorms. The thunderstorms investigated were generally small, local, discrete and short-lived phenomena. They were selected for study because of almost stationary position over orography, rendering easy observation because they remained contained within a particular mountain region before dissipating. The results show that large transfers of air and water vapour occur from the Swiss plain to the mountains on such days, with up to a 50% increase in GPS IWV values at individual Alpine stations, coincident with strong airflow convergence in the same locality.

  15. Comparative estimate of the effectiveness of different algorithms for the radar classification of thunderstorms and showers

    Science.gov (United States)

    Linev, A. G.; Oprishko, V. S.; Popova, N. D.; Salman, Y. M.

    1975-01-01

    Several schemes for discriminating severe weather phenomena with the aid of different algorithms are examined. The schemes were tested on the same sample. A comparative estimate of the effectiveness of the different algorithms for classifying thunderstorms and showers is carried out.

  16. Thunderstorm nowcasting by means of lightning and radar data: algorithms and applications in northern Italy

    Science.gov (United States)

    Bonelli, P.; Marcacci, P.

    2008-10-01

    Thunderstorms and their ground effects, such as flash floods, hail, lightning, strong winds, and tornadoes, are responsible for most weather damages in northern Italy, especially in the warm season from May to September. A nowcasting and warning system focused on severe thunderstorm events would be useful to reduce risks for people involved in outside activities and for electric, telecommunication, and sensitive industrial business. C-band radar and Lighting Location Systems provide useful, fast and high resolution data for the detection of convective systems and for following their dynamics. The whole of northern Italy is covered by radar with a resolution of 1 km and by a lightning network with a mean accuracy of 0.5 km on the single point of impact. The authors present an algorithm developed for tracking high intensity storm cells by means of radar and lightning data. Application to northern Italy reveals that tracking thunderstorm cells can be used as an alert system that may help prevent damages from extreme weather, as well as allowing for studying the correlation among lightning, rainfall and tornado occurrence. Assessing the algorithm skill is also discussed, and a forecast verification method is described and applied for the duration of a thunderstorm season.

  17. Thunderstorm nowcasting by means of lightning and radar data: algorithms and applications in northern Italy

    Directory of Open Access Journals (Sweden)

    P. Bonelli

    2008-10-01

    Full Text Available Thunderstorms and their ground effects, such as flash floods, hail, lightning, strong winds, and tornadoes, are responsible for most weather damages in northern Italy, especially in the warm season from May to September. A nowcasting and warning system focused on severe thunderstorm events would be useful to reduce risks for people involved in outside activities and for electric, telecommunication, and sensitive industrial business. C-band radar and Lighting Location Systems provide useful, fast and high resolution data for the detection of convective systems and for following their dynamics. The whole of northern Italy is covered by radar with a resolution of 1 km and by a lightning network with a mean accuracy of 0.5 km on the single point of impact. The authors present an algorithm developed for tracking high intensity storm cells by means of radar and lightning data. Application to northern Italy reveals that tracking thunderstorm cells can be used as an alert system that may help prevent damages from extreme weather, as well as allowing for studying the correlation among lightning, rainfall and tornado occurrence. Assessing the algorithm skill is also discussed, and a forecast verification method is described and applied for the duration of a thunderstorm season.

  18. Profuse activity of blue electrical discharges at the tops of thunderstorms

    DEFF Research Database (Denmark)

    Chanrion, Olivier; Neubert, Torsten; Mogensen, Andreas

    2017-01-01

    a color video footage of thunderstorms over the Bay of Bengal from the International Space Station. The observations show a multitude of blue, km-scale, discharges at the cloud top layer at ~18 km altitude and a pulsating blue discharge propagating into the stratosphere reaching ~40 km altitude...

  19. Possible development mechanisms of pre-monsoon thunderstorms over northeast and east India

    Science.gov (United States)

    Narayanan, Sunanda; Vishwanathan, Gokul; Mrudula, G.

    2016-05-01

    Thunderstorms are mesoscale convective systems of towering cumulonimbus clouds of high vertical and horizontal extent lasting from a few minutes to several hours. Pre-monsoon thundershowers over the past 10 years have been analyzed to understand the organization, horizontal and vertical development and dissipation of such severe events. Kalbaisakhi's/ Norwester's over north east and East India is given preference in this study, while some of the other extreme events are also analyzed due to their severity. The meteorological parameters like horizontal and vertical wind, precipitable water etc., and derived variables such as Severe Weather Threat (SWEAT) Index, Convective Available Potential Energy (CAPE), and Convective Inhibition Energy (CINE) of the identified cases are analyzed using observations from NCEP and IMD. Satellite observations from IMD and TRMM are also used to analyze the development and moisture flow of such systems. The analysis shows that some of the parameters display a clear signature of developing thunderstorms. It is also seen that cloud parameters such as convective precipitation rate and convective cloud cover from NCEP FNL didn't show much variation during the development of storms, which may be attributed to the limitation of spatial and temporal resolution. The parameters which showed indications of a developing thunderstorm were studied in detail in order to understand the possible mechanisms behind the development and organization of thunderstorm cells.

  20. Far from thunderstorm UV transient events in the atmosphere measured by Vernov satellite

    Science.gov (United States)

    Morozenko, Violetta; Klimov, Pavel; Khrenov, Boris; Gali, Garipov; Margarita, Kaznacheeva; Mikhail, Panasyuk; Sergei, Svertilov; Robert, Holzworth

    2016-04-01

    The steady self-contained classification of events such as sprites, elves, blue jets emerged for the period of transient luminous events (TLE) observation. In accordance with TLE origin theories the presence of the thunderstorm region where the lightnings with the large peak current generating in is necessary. However, some far-from-thunderstorm region events were also detected and revealed to us another TLE generating mechanisms. For the discovering of the TLE nature the Universitetsky-Tatiana-2 and Vernov satellites were equipped with ultraviolet (240-400 nm) and red-infrared ( >610 nm) detectors. In both detector it was carried out regardless the lightnings with the guidance by the flashes in the UV wavelength where lightning's emitting is quite faint. The lowered threshold on the Vernov satellite allowed to select the great amount of TLE with the numerous far-from-thunderstorm region events examples. such events were not conjuncted with lightning activity measured by global lightning location network (WWLLN) on the large area of approximately 107 km2 for 30 minutes before and after the time of registration. The characteristic features of this type of event are: the absence of significant signal in the red-infrared detector's channel; a relatively small number of photons (less than 5 ṡ 1021). A large number of without lightning flash were detected at high latitudes over the ocean (30°S - 60°S). Lightning activity in the magnetic conjugate point also was analyzed. The relationship of far-from-thunderstorm region events with the specific lightning discharges didn't confirmed. Far-from-thunderstorm events - a new type of transient phenomena in the upper atmosphere is not associated with the thunderstorm activity. The mechanism of such discharges is not clear, though it was accumulated a sufficient amount of experimental facts of the existence of such flashes. According to the data of Vernov satellite the temporal profile, duration, location with earth

  1. Analysis of stability parameters in relation to precipitation associated with pre-monsoon thunderstorms over Kolkata, India

    Indian Academy of Sciences (India)

    H P Nayak; M Mandal

    2014-06-01

    The upper air RS/RW (Radio Sonde/Radio Wind) observations at Kolkata (22.65N, 88.45E) during premonsoon season March–May, 2005–2012 is used to compute some important dynamic/thermodynamic parameters and are analysed in relation to the precipitation associated with the thunderstorms over Kolkata, India. For this purpose, the pre-monsoon thunderstorms are classified as light precipitation (LP), moderate precipitation (MP) and heavy precipitation (HP) thunderstorms based on the magnitude of associated precipitation. Richardson number in non-uniformly saturated (i*) and saturated atmosphere (i); vertical shear of horizontal wind in 0–3, 0–6 and 3–7 km atmospheric layers; energy-helicity index (EHI) and vorticity generation parameter (VGP) are considered for the analysis. The instability measured in terms of Richardson number in non-uniformly saturated atmosphere (i*) well indicate the occurrence of thunderstorms about 2 hours in advance. Moderate vertical wind shear in lower troposphere (0–3 km) and weak shear in middle troposphere (3–7 km) leads to heavy precipitation thunderstorms. The wind shear in 3–7 km atmospheric layers, EHI and VGP are good predictors of precipitation associated with thunderstorm. Lower tropospheric wind shear and Richardson number is a poor discriminator of the three classified thunderstorms.

  2. The direct radiative effect of wildfire smoke on a severe thunderstorm event in the Baltic Sea region

    Science.gov (United States)

    Toll, V.; Männik, A.

    2015-03-01

    On August 8, 2010, a severe derecho type thunderstorm in the Baltic Sea region coincided with smoke from wildfires in Russia. Remarkable smoke aerosol concentrations, with a maximum aerosol optical depth of more than 2 at 550 nm, were observed near the thunderstorm. The impact of the wildfire smoke on the thunderstorm through direct radiative effects was investigated using the Hirlam Aladin Research for Mesoscale Operational Numerical Weather Prediction in Euromed (HARMONIE) model. HARMONIE was successfully able to resolve the dynamics of the thunderstorm, and simulations that considered the influence of the smoke-related aerosols were compared to simulation without aerosols. As simulated by the HARMONIE model, the smoke reduced the shortwave radiation flux at the surface by as much as 300 W/m2 and decreased the near-surface temperature by as much as 3 °C in the vicinity of the thunderstorm and respectively 100 W/m2 and 1 °C in the thunderstorm region. Atmospheric instability decreased through the direct radiative effect of aerosols, and several dynamic features of the simulated thunderstorm appeared slightly weaker.

  3. Experimental Research on Atmospheric Electric Field and Extensive Air Shower Particle Increasing During Thunderstorms with ARGO-YBJ

    Institute of Scientific and Technical Information of China (English)

    XU Bin; ZHANG Ying; JIA Huan-Yu

    2008-01-01

    From April lst to August 14th, 2006, thunderstorms had been recorded at Yangbajing Cosmic Ray Observatory by ARGO-YBJ experiment. This paper analyzed the correlation between atmospheric electric field (AEF) and "scaler mode" counting rate during thunderstorm. Counting rates of multiplicities n = 1,2 were found to have a large increase ( from 1.02% to 9.03% ), while there was few or no changes in those of multiplicities n =3 and n≥4 during the thunderstorms. The counts of different multiplicities had different feedbacks on the violent change of AEF, which showed that their energy and most components were distinguishing.

  4. Analysis of physical parameter field and echo characteristics of Doppler radar in a thunderstorm process%一次雷暴大风的物理环境场和多普勒雷达回波特征

    Institute of Scientific and Technical Information of China (English)

    阎访; 陈静; 卞韬; 廖颖慧; 张翠华

    2013-01-01

    A thunderstorm disaster appeared in Shijiazhuang region from 15:00 to 18:00 on August 27,2009. The mesoscale synoptic systems of this process such as gust front, squall line and mesocyclone and so on were detected by a Doppler radar at Xinle county of Shijiazhuang. The characteristics of physical parameter field of this process and Doppler radar product were analyzed. The results show that unstable stratification of temperature inversion in the low level and vertical wind shear in the middle and low levels provide favorable conditions for strong convec-tive development. Gust front has feedback action on the development of convective storm intensity. When gust front is moving away from the convective storm,the convective storm weakens or even dies out; when both are gradually close to each other,the convective storm strengthens or even develops into a supercell convective storm. Multiple single convective storm belt arrangement constitutes a squall line system, which brings wind speed spurt, wind zag,pressure upwelling and temperature falling. The supercell convective storm has the typical features of echoes with a "hook" shape,a "herringbone" shape,a "bow" shape,and deep lasting mesocyclone. The ground destructive wind is mainly brought by supercell convective storms.%2009年8月27日15-18时,石家庄地区出现雷暴大风灾害性强对流天气过程,石家庄北部新乐县多普勒雷达探测到了完整的阵风锋、飑线和中气旋等中尺度天气系统,对此次雷暴大风的环境场和多普勒雷达产品进行分析.结果表明:低层逆温、中低层垂直风切变较强的不稳定层结为强对流天气的发生发展提供了有利环境条件.阵风锋对对流风暴发展强度具有反馈作用,当二者逐渐远离时,对流风暴强度减弱甚至消亡;当二者逐渐靠近时,对流风暴发展加强,甚至发展为超级单体对流风暴.多单体对流风暴带状排列构成飑线系统,所经测站出现风速突增、风

  5. A supercell, Bloch wave method for calculating low-energy electron reflectivity with applications to free-standing graphene and molybdenum disulfide

    Science.gov (United States)

    McClain, John

    This dissertation reports on a novel theoretical and computational framework for calculating low-energy electron reflectivities from crystalline surfaces and its application to two layered systems of two-dimensional materials, graphene and molybdenum disulfide. The framework provides a simple and efficient approach through the matching of a small set of Fourier components of Bloch wave solutions to the Schrodinger Equation in a slab-in-supercell geometry to incoming and outgoing plane waves on both sides of the supercell. The implementation of this method is described in detail for the calculation of reflectivities in the lowest energy range, for which only specular reflection is allowed. This implementation includes the calculation of reflectivities from beams with normal or off-normal incidence. Two different algorithms are described in the case of off-normal incidence which differ in their dependence on the existence of a symmetry with a mirror plane parallel to the crystal surface. Applications to model potentials in one, two, and three dimensions display consistent results when using different supercell sizes and convergent results with the density of Fourier grids. The design of the Bloch wave matching also allows for the accurate modeling of crystalline slabs through the use of realistic potentials determined via density functional theory. The application of the method to low-energy electron scattering from free-standing systems of a few layers of graphene, including the use of these realistic potentials, demonstrates this ability of the method to accurately model real systems. It reproduces the layer-dependent oscillations found in experimental, normal incidence reflectivity curves for a few layers of graphene grown on silicon carbide. The normal incidence reflectivity curves calculated for slabs consisting of few-layer graphene on 10 layers of nickel show some qualitative agreement with experiment. General incidence reflectivity spectra for free

  6. Instability indices and forecasting thunderstorms: the case of 30 April 2009

    Directory of Open Access Journals (Sweden)

    S. Tajbakhsh

    2012-02-01

    Full Text Available In this paper, one meteorological case study for two Iranian airports are presented. Attempts have been made to study the predefined threshold amounts of some instability indices such as vertical velocity and relative humidity. Two important output variables from a numerical weather prediction model have been used to survey thunderstorms. The climatological state of thunder days in Iran has been determined to aid in choosing the airports for the case studies. The synoptic pattern, atmospheric thermodynamics and output from a numerical weather prediction model have been studied to evaluate the occurrence of storms and to verify the threshold instability indices that are based on Gordon and Albert (2000 and Miller (1972.

    Using data from the Statistics and Data Center of the Iran Meteorological Organization, 195 synoptic stations were used to study the climatological pattern of thunderstorm days in Iran during a 15-yr period (1991–2005. Synoptic weather maps and thermodynamic diagrams have been drawn using data from synoptic stations and radiosonde data. A 15-km resolution version of the WRF numerical model has been implemented for the Middle East region with the assistance of global data from University Corporation for Atmospheric Research (UCAR.

    The Tabriz airport weather station has been selected for further study due to its high frequency of thunderstorms (more than 35 thunderstorm days per year and the existence of an upper air station. Despite the fact that storms occur less often at the Tehran weather station, the station has been chosen as the second case study site due to its large amount of air traffic. Using these two case studies (Tehran at 00:00 UTC, 31 April 2009 and Tabriz at 12:00 UTC, 31 April 2009, the results of this research show that the threshold amounts of 30 °C for KI, −2 °C for LI and −3 °C for SI suggests the occurrence and non-occurrence of thunderstorms at the Tehran and Tabriz stations

  7. X-ray absorption near edge structure/electron energy loss near edge structure calculation using the supercell orthogonalized linear combination of atomic orbitals method.

    Science.gov (United States)

    Ching, Wai-Yim; Rulis, Paul

    2009-03-11

    Over the last eight years, a large number of x-ray absorption near edge structure (XANES) and/or electron energy loss near edge structure (ELNES) spectroscopic calculations for complex oxides and nitrides have been performed using the supercell-OLCAO (orthogonalized linear combination of atomic orbitals) method, obtaining results in very good agreement with experiments. The method takes into account the core-hole effect and includes the dipole matrix elements calculated from ab initio wavefunctions. In this paper, we describe the method in considerable detail, emphasizing the special advantages of this method for large complex systems. Selected results are reviewed and several hitherto unpublished results are also presented. These include the Y K edge of Y ions segregated to the core of a Σ31 grain boundary in alumina, O K edges of water molecules, C K edges in different types of single walled carbon nanotubes, and the Co K edge in the cyanocobalamin (vitamin B(12)) molecule. On the basis of these results, it is argued that the interpretation of specific features of the calculated XANES/ELNES edges is not simple for complex material systems because of the delocalized nature of the conduction band states. The long-standing notion of the 'fingerprinting' technique for spectral interpretation of experimental data is not tenable. A better approach is to fully characterize the structure under study, using either crystalline data or accurate ab initio modeling. Comparison between calculated XANES/ELNES spectra and available measurements enables us to ascertain the validity of the modeled structure. For complex crystals or structures, it is necessary to use the weighted sum of the spectra from structurally nonequivalent sites for comparison with the measured data. Future application of the supercell-OLCAO method to complex biomolecular systems is also discussed.

  8. X-ray absorption near edge structure/electron energy loss near edge structure calculation using the supercell orthogonalized linear combination of atomic orbitals method

    Energy Technology Data Exchange (ETDEWEB)

    Ching, W.-Y.; Rulis, Paul [Department of Physics, University of Missouri-Kansas City, Kansas City, MO 64110 (United States)

    2009-03-11

    Over the last eight years, a large number of x-ray absorption near edge structure (XANES) and/or electron energy loss near edge structure (ELNES) spectroscopic calculations for complex oxides and nitrides have been performed using the supercell-OLCAO (orthogonalized linear combination of atomic orbitals) method, obtaining results in very good agreement with experiments. The method takes into account the core-hole effect and includes the dipole matrix elements calculated from ab initio wavefunctions. In this paper, we describe the method in considerable detail, emphasizing the special advantages of this method for large complex systems. Selected results are reviewed and several hitherto unpublished results are also presented. These include the Y K edge of Y ions segregated to the core of a {sigma}31 grain boundary in alumina, O K edges of water molecules, C K edges in different types of single walled carbon nanotubes, and the Co K edge in the cyanocobalamin (vitamin B{sub 12}) molecule. On the basis of these results, it is argued that the interpretation of specific features of the calculated XANES/ELNES edges is not simple for complex material systems because of the delocalized nature of the conduction band states. The long-standing notion of the 'fingerprinting' technique for spectral interpretation of experimental data is not tenable. A better approach is to fully characterize the structure under study, using either crystalline data or accurate ab initio modeling. Comparison between calculated XANES/ELNES spectra and available measurements enables us to ascertain the validity of the modeled structure. For complex crystals or structures, it is necessary to use the weighted sum of the spectra from structurally nonequivalent sites for comparison with the measured data. Future application of the supercell-OLCAO method to complex biomolecular systems is also discussed.

  9. X-ray absorption near edge structure/electron energy loss near edge structure calculation using the supercell orthogonalized linear combination of atomic orbitals method

    Science.gov (United States)

    Ching, Wai-Yim; Rulis, Paul

    2009-03-01

    Over the last eight years, a large number of x-ray absorption near edge structure (XANES) and/or electron energy loss near edge structure (ELNES) spectroscopic calculations for complex oxides and nitrides have been performed using the supercell-OLCAO (orthogonalized linear combination of atomic orbitals) method, obtaining results in very good agreement with experiments. The method takes into account the core-hole effect and includes the dipole matrix elements calculated from ab initio wavefunctions. In this paper, we describe the method in considerable detail, emphasizing the special advantages of this method for large complex systems. Selected results are reviewed and several hitherto unpublished results are also presented. These include the Y K edge of Y ions segregated to the core of a Σ31 grain boundary in alumina, O K edges of water molecules, C K edges in different types of single walled carbon nanotubes, and the Co K edge in the cyanocobalamin (vitamin B12) molecule. On the basis of these results, it is argued that the interpretation of specific features of the calculated XANES/ELNES edges is not simple for complex material systems because of the delocalized nature of the conduction band states. The long-standing notion of the 'fingerprinting' technique for spectral interpretation of experimental data is not tenable. A better approach is to fully characterize the structure under study, using either crystalline data or accurate ab initio modeling. Comparison between calculated XANES/ELNES spectra and available measurements enables us to ascertain the validity of the modeled structure. For complex crystals or structures, it is necessary to use the weighted sum of the spectra from structurally nonequivalent sites for comparison with the measured data. Future application of the supercell-OLCAO method to complex biomolecular systems is also discussed.

  10. Observation and analysis of electrical structure change and diversity in thunderstorms on the Qinghai-Tibet Plateau

    Science.gov (United States)

    Li, Yajun; Zhang, Guangshu; Wang, Yanhui; Wu, Bin; Li, Jing

    2017-09-01

    A comprehensive observation on thunderstorms was conducted in the Qinghai area by using a very high frequency three-dimensional lightning mapping system and Doppler radar. The spatio-temporal evolution of the charge structure of the isolated thunderstorm was analyzed according to the developing process of thunderstorm, and the reasons for the change in charge structure diversity were studied. During the initial developing and mature stages of the thunderstorm, the charge structure was a steady negative dipole polarity, i.e., the negative charge region was above the positive charge region. Furthermore, the total number of flashes was lower during these two stages. During the thunderstorm's dissipation stage, the charge structure was varied and complicated, with a positive dipole, negative dipole, and a tripole charge structure changing and coexisting during this stage. This charge structure diversity was primarily caused by the collision and merging of two local thunderstorm cells, leading to a charge rearrangement and distribution and the formation of a new charge structure. The frequency of the negative cloud-to-ground and intracloud flashes increased sharply in the dissipation stage, reaching a maximum value. The increase in frequency of negative cloud-to-ground was mainly caused by the lower positive charge weakening during the dissipation stage. In addition, the relationship between charging regions and temperature layers was analyzed by combining sounding temperature data with the theory of a non-inductive charging mechanism.

  11. Search for possible relationship between volcanic ash particles and thunderstorm lightning activity

    Science.gov (United States)

    Várai, A.; Vincze, M.; Lichtenberger, J.; Jánosi, I. M.

    2011-12-01

    Explosive volcanic eruptions that eject columns of ash from the crater often generate lightning discharges strong enough to be remotely located by very low frequency radio waves. A fraction of volcanic ash particles can stay and disperse long enough to have an effect on weather phenomena days later such as thunderstorms and lightnings. In this work we report on lightning activity analysis over Europe following two recent series of volcanic eruptions in order to identify possible correlations between ash release and subsequent thunderstorm flash frequency. Our attempts gave negative results which can be related to the fact that we have limited information on local atmospheric variables of high enough resolution, however lightning frequency is apparently determined by very local circumstances.

  12. Probing Atmospheric Electric Fields in Thunderstorms through Radio Emission from Cosmic-Ray-Induced Air Showers

    CERN Document Server

    Schellart, P; Buitink, S; Corstanje, A; Enriquez, J E; Falcke, H; Hörandel, J R; Nelles, A; Rachen, J P; Rossetto, L; Scholten, O; ter Veen, S; Thoudam, S; Ebert, U; Koehn, C; Rutjes, C; Alexov, A; Anderson, J M; Avruch, I M; Bentum, M J; Bernardi, G; Best, P; Bonafede, A; Breitling, F; Broderick, J W; Brüggen, M; Butcher, H R; Ciardi, B; de Geus, E; de Vos, M; Duscha, S; Eislöffel, J; Fallows, R A; Frieswijk, W; Garrett, M A; Grießmeier, J; Gunst, A W; Heald, G; Hessels, J W T; Hoeft, M; Holties, H A; Juette, E; Kondratiev, V I; Kuniyoshi, M; Kuper, G; Mann, G; McFadden, R; McKay-Bukowski, D; McKean, J P; Mevius, M; Moldon, J; Norden, M J; Orru, E; Paas, H; Pandey-Pommier, M; Pizzo, R; Polatidis, A G; Reich, W; Röttgering, H; Scaife, A M M; Schwarz, D J; Serylak, M; Smirnov, O; Steinmetz, M; Swinbank, J; Tagger, M; Tasse, C; Toribio, M C; van Weeren, R J; Vermeulen, R; Vocks, C; Wise, M W; Wucknitz, O; Zarka, P

    2015-01-01

    We present measurements of radio emission from cosmic ray air showers that took place during thunderstorms. The intensity and polarization patterns of these air showers are radically different from those measured during fair-weather conditions. With the use of a simple two-layer model for the atmospheric electric field, these patterns can be well reproduced by state-of-the-art simulation codes. This in turn provides a novel way to study atmospheric electric fields.

  13. Direct effects of lightning on an aircraft during intentional penetrations of thunderstorms. [T-28 aircraft

    Science.gov (United States)

    Musil, D. J.; Prodan, J.

    1980-01-01

    An armored T-28 aircraft was struck by lightning on two different days while participating in the 1979 severe environmental storm and mesoscale experiment in Oklahoma. The T-28, which is specially armored and instrumented, was making intentional penetrations of thunderstorms and was struck twice on 30 May and once on 5 June. Various degrees of damage, mainly in the form of large burn spots and holes, resulted to the aircraft.

  14. Gamma ray and fair weather electric field measurements during thunderstorms: indications for TGEs?

    Science.gov (United States)

    Reuveni, Yuval; Yair, Yoav; Steinitz, Gideon; Price, Colin; Pustil'nik, Lev; Yaniv, Roy; Hamiel, Yariv; Katz, Evgeni

    2016-04-01

    We report coincidences of ground-level gamma-ray enhancements with strong electric fields typical of lightning discharges, measured at a mountainous site in northern Israel. High-energy emissions detected on the Earth's surface during thunderstorms supposedly initiate Thunderstorm Ground Enhancements (TGEs) of fluxes of electrons, neutrons and gamma rays that can last tens of minutes. Such enhancements are thought to be related to Extensive Cloud Showers (ECSs) initiated between the main negative charge center and the lower positive charge pocket in mature thunderstorms (Chilingarian et al., 2015). The Cosmic Ray and Space Weather Center located at Mt. Hermon hosts a gamma ray detector alongside a continuous multi-parametric array consisting of a Global Navigation Satellite Systems (GNSS) geodetic receiver (for measuring Precipitable Water Vapor (PWV) and ionospheric Total Electron Content (TEC)), vertical atmospheric electric field (Ez) and current (Jz) and a neutron super monitor (for cosmic ray measurements). The diurnal variations in fair-weather conditions exhibit a clear 24-hour periodicity, related to the diurnal variation of atmospheric parameters. During several severe thunderstorms that occurred over Israel and near the Mt. Hermon station in October and November 2015, we recorded several instantaneous enhancements in the counts of Gamma rays, which lasted ten of minutes, and that coincided with peaks in the vertical electric field and current. Lightning data obtained from the Israeli Lightning Detection Network (ILDN) show that these peaks match the occurrences of close-by CG lightning discharges. This talk will present correlations between the properties of parent flashes and the observed peaks, and discuss possible mechanisms.

  15. Establishment of a Kind of Three-dimensional Thunderstorm Cloud Electrification-Discharge Mode

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    [Objective] The research aimed to study the establishment of a kind of three-dimensional thunderstorm cloud electrification-discharge mode.[Method] Based on a kind of three-dimensional strong convective cloud mode,several parameterization schemes of electrification-discharge mechanism which were mature and had experimental basis were coupled into the strong convective cloud mode.The three-dimensional strong convective mode could simulate electrification-discharge process,and the three-dimensional thundersto...

  16. Electrical soundings in the decay stage of a thunderstorm in the Pingliang region

    Science.gov (United States)

    Zhang, Tinglong; Zhao, Zhongkuo; Zhao, Yang; Wei, Changxiong; Yu, Hai; Zhou, Fangcong

    2015-10-01

    An electric field sounding system, based on corona discharge, was designed to measure the vertical component of the electric fields in a thunderstorm. The decay stage of a thunderstorm that occurred during the night of August 20, 2012, in the Pingliang region, China (35.57°N, 106.59°E, 1620 m above sea level (asl)), was investigated by two balloon-borne electrical soundings. The results of the first sounding showed that the thunderstorm had a tripole charge structure: a lower positive charge region located at temperatures of 3 to 15 °C (2.0-4.0 km asl); a middle negative charge region located at temperatures of - 3 to 3 °C (4.5-5.3 km asl); and an upper positive charge region at temperatures of - 10 to - 3 °C (5.3-6.3 km asl). In addition, there was a negative screen layer at the bottom of the thunderstorm with a depth of about 400 m. The charge density of the middle negative charge region was larger than that of the lower and upper positive charge regions. Influenced by the downdraft of precipitation, each charge region moved down to a lower altitude region. The results of the second sounding showed that the lower positive charge center totally disappeared and only the middle negative charge region (3.7-4.2 km asl) and upper positive charge region (4.2-4.7 km asl) remained. We conclude that the downdraft with precipitation caused the dissipation of the lower positive charge region. Compared with the first sounding result, we found that the charge density increased and the depth decreased for both of the charge regions.

  17. Balloon Measurements of Electric Fields in Thunderstorms: A Modern Version of Benjamin Franklin's Kite

    Science.gov (United States)

    Marshall, T. C.; Stolzenburg, M.

    2006-12-01

    One of Benjamin Franklin's most famous experiments was the kite experiment, which showed that thunderstorms are electrically charged. It is not as commonly noted that the kite experiment was also one of the the first attempts to make an in situ measurement of any storm parameter. Franklin realized the importance of making measurements close to and within storms, and this realization has been shared by later atomspheric scientists. In this presentation we focus on a modern version of Franklin's kite--instrumented balloons--used for in situ measurements of electric field and other storm parameters. In particular, most of our knowledge of the charge structure inside thunderstorms is based on balloon soundings of electric field. Balloon measurements of storm electricity began with the work of Simpson and colleagues in the 1930's and 1940's. The next major instrumentation advances were made by Winn and colleagues in the 1970's and 1980's. Today's instruments are digital versions of the Winn design. We review the main instrument techniques that have allowed balloons to be the worthy successors to kites. We also discuss some of the key advances in our understanding of thunderstorm electrification made with in situ balloon-borne instruments.

  18. On the possibility of phosphenes being generated by the energetic radiation from lightning flashes and thunderstorms

    Energy Technology Data Exchange (ETDEWEB)

    Cooray, Vernon, E-mail: Vernon.Cooray@angstrom.uu.se [Division for Electricity, Department of Engineering Sciences, Uppsala University, Box 534, 751 21 Uppsala (Sweden); Cooray, Gerald [Department of Clinical Neuroscience, Karolinska Institute, Stockholm (Sweden); Dwyer, Joseph [Florida Institute of Technology, Melbourne, FL (United States)

    2011-10-03

    After the first report of this phenomenon by Apollo 11 astronauts, experiments conducted in space and on the ground confirmed the creation of phosphenes by the interaction of energetic radiation with the human visual system. The aim of this Letter is to show that the energetic radiation generated in the form of X-rays, gamma rays, electrons and neutrons by thunderstorms and lightning is strong enough for the creation of phosphenes in humans. It is also pointed out that some of the visual observations reported during thunderstorms might be attributable to phosphenes excited by this energetic radiation. -- Highlights: → Radiation in space consists of X-rays, γ-rays, protons, neutrons and electrons. → Studies of NASA confirm creation of phosphene in humans by such energetic radiation. → Energetic radiation also exists in the vicinity of thunderstorms and lightning. → It is shown that this radiation is strong enough to generate phosphene in humans. → Some of these visual experiences could be misinterpreted as ball lightning.

  19. Analysis of a mesoscale convective system that produced a single sprite

    Science.gov (United States)

    Yang, Jing; Lu, Gaopeng; Liu, Ningyu; Cui, Haihua; Wang, Yu; Cohen, Morris

    2017-02-01

    Sprites are brief optical emissions occurring above thunderstorms. Features of sprites and their parent thunderstorms and lightning activities have been studied by many researchers. Here, we report a single sprite recorded over a mesoscale convective system during its life cycle in Northeast China. The results show that the sprite might have been a dancing one, with a 20 km horizontal displacement from its parent cloud-to-ground flash (CG) and a 38 ms time delay; all the sprite elements occurred during the continuing current process of the parent flash. The peak current of the parent CG was the largest during the almost one-hour time window containing the sprite, and the absolute values of all the negative flashes were smaller than 100 kA during the same time period and did not produce sprite. The sprite did not occur during the time period in which the maximum area of the thunderstorm reached. The occurrence of sprite corresponded well with the decay of the thunderstorm convection, and no significant relationship between the occurrence of sprite and the increase in the 30-35 dBZ and 35-40 dBZ interval was found. The large wind gradient in the 8-12 km region of the thunderstorm may have played an important role in the sprite production.

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

    Directory of Open Access Journals (Sweden)

    V. K. Meyer

    2013-01-01

    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 information (TL for thunderstorm tracking and nowcasting. 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 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 contributes to more detailed

  1. 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

  2. Sensitivity of WRF cloud microphysics to simulations of a severe thunderstorm event over Southeast India

    Energy Technology Data Exchange (ETDEWEB)

    Rajeevan, M.; Kesarkar, A.; Rao, T.N.; Radhakrishna, B. [National Atmospheric Research Lab., Gadanki (India); Thampi, S.B. [India Meteorological Dept., Chennai (India). Doppler Weather Radar Div.; Rajasekhar, M. [ISRO, Sriharikota (India). SHAR Center

    2010-07-01

    In the present study, we have used the Weather Research and Forecasting (WRF) model to simulate the features associated with a severe thunderstorm observed over Gadanki (13.5 N,79.2 E), over southeast India, on 21 May 2008 and examined its sensitivity to four different microphysical (MP) schemes (Thompson, Lin, WSM6 and Morrison). We have used the WRF model with three nested domains with the innermost domain of 2 km grid spacing with explicit convection. The model was integrated for 36 h with the GFS initial conditions of 00:00 UTC, 21 May 2008. For validating simulated features of the thunderstorm, we have considered the vertical wind measurements made by the Indian MST radar installed at Gadanki, reflectivity profiles by the Doppler Weather Radar at Chennai, and automatic weather station data at Gadanki. There are major differences in the simulations of the thunderstorm among the MP schemes, in spite of using the same initial and boundary conditions and model configuration. First of all, all the four schemes simulated severe convection over Gadanki almost an hour before the observed storm. The DWR data suggested passage of two convective cores over Gadanki on 21 May, which was simulated by the model in all the four MP schemes. Comparatively, the Thompson scheme simulated the observed features of the updraft/downdraft cores reasonably well. However, all the four schemes underestimated strength and vertical extend of the updraft cores. The MP schemes also showed problems in simulating the downdrafts associated with the storm. While the Thompson scheme simulated surface rainfall distribution closer to observations, the other three schemes overestimated observed rainfall. However, all the four MP schemes simulated the surface wind variations associated with the thunderstorm reasonably well. The model simulated reflectivity profiles were consistent with the observed reflectivity profile, showing two convective cores. These features are consistent with the simulated

  3. Use of RegCM gridded dataset for thunderstorm favorable conditions analysis over Poland—climatological approach

    Science.gov (United States)

    Walawender, Ewelina; Kielar, Rafał; Ustrnul, Zbigniew

    2017-01-01

    The paper analyzes equivalent data for a low density meteorological station network (spatially discontinuous data) and poor temporal homogeneity of thunderstorm observational data. Due to that, a Regional Climate Model (RegCM) dataset was tested. The Most Unstable Convective Available Potential Energy index value (MUCAPE) above the 200 J kg-1 threshold was selected as a predictor describing favorable conditions for the occurrence of thunderstorms. The quality of the dataset was examined through a comparison between model results and soundings from several aerological stations in Central Europe. Good, statistically significant (0.05 significance level) results were obtained through correlation analysis; the value of Pearson's correlation coefficient was above 0.8 in every single case. Then, using methods associated with gridded climatology, data series for 44 weather stations were derived and an analysis of correlation between RegCM modeled data and in situ thunderstorm observations was conducted with coefficients in the range of 0.75-0.90. The possibility of employing the dataset in thunderstorm climatology analysis was checked via a few examples by mapping monthly, seasonal, and annual means. Moreover, long-term variability and trend analysis along with modeled MUCAPE data were tested. As a result, the RegCM modeled MUCAPE gridded dataset was proposed as an easily available, suitable, and valuable predictor for thunderstorm climatology analysis and mapping. Finally, some limitations are discussed and recommendations for further improvements are given.

  4. Exceptional sequence of severe thunderstorms and related flash floods in May and June 2016 in Germany - Part 1: Meteorological background

    Science.gov (United States)

    Piper, David; Kunz, Michael; Ehmele, Florian; Mohr, Susanna; Mühr, Bernhard; Kron, Andreas; Daniell, James

    2016-12-01

    During a 15-day episode from 26 May to 9 June 2016, Germany was affected by an exceptionally large number of severe thunderstorms. Heavy rainfall, related flash floods and creek flooding, hail, and tornadoes caused substantial losses running into billions of euros (EUR). This paper analyzes the key features of the severe thunderstorm episode using extreme value statistics, an aggregated precipitation severity index, and two different objective weather-type classification schemes. It is shown that the thunderstorm episode was caused by the interaction of high moisture content, low thermal stability, weak wind speed, and large-scale lifting by surface lows, persisting over almost 2 weeks due to atmospheric blocking.For the long-term assessment of the recent thunderstorm episode, we draw comparisons to a 55-year period (1960-2014) regarding clusters of convective days with variable length (2-15 days) based on precipitation severity, convection-favoring weather patterns, and compound events with low stability and weak flow. It is found that clusters with more than 8 consecutive convective days are very rare. For example, a 10-day cluster with convective weather patterns prevailing during the recent thunderstorm episode has a probability of less than 1 %.

  5. Magnetic exchange interactions and critical temperature of the nanolaminate M n2GaC from first-principles supercell methods

    Science.gov (United States)

    Thore, A.; Dahlqvist, M.; Alling, B.; Rosen, J.

    2016-02-01

    In this work, we employ and critically evaluate a first-principles approach based on supercell calculations for predicting the magnetic critical order-disorder temperature Tc. As a model material we use the recently discovered nanolaminate M n2GaC . First, we derive the exchange interaction parameters Ji j between pairs of Mn atoms on sites i and j of the bilinear Heisenberg Hamiltonian using the novel magnetic direct cluster averaging method (MDCA), and then compare the J's from the MDCA calculations to the same parameters calculated using the Connolly-Williams method. We show that the two methods yield closely matching results, but observe that the MDCA method is computationally less effective when applied to highly ordered phases such as M n2GaC . Secondly, Monte Carlo simulations are used to derive the magnetic energy, specific heat, and Tc. For M n2GaC , we find Tc=660 K . The uncertainty in the calculated Tc caused by possible uncertainties in the J's is discussed and exemplified in our case by an analysis of the impact of the statistical uncertainties of the MDCA-derived J's , resulting in a Tc distribution with a standard deviation of 133 K.

  6. Anomalous electric field changes and high flash rate beneath a thunderstorm in northeast India

    Indian Academy of Sciences (India)

    S D Pawar; P Murugavel; V Gopalakrishnan

    2010-10-01

    In spite of many experimental and theoretical studies the relationships between storm dynamics, severe weather,and lightning activity have been least understood.Measurements of electric field made under a severe thunderstorm at a northeastern Indian station,Guwahati,India are reported. Lightning flash rate increases drastically to about 84 flashes per minute (fpm)during the active stage which lasted for about 7 minutes,from about 15 flashes per minute during the initial phase of thunderstorm.Sudden increase in lightning flash rate (‘lightning jump ’)of about 65 fpm/min is also observed in the beginning of the active stage.The dissipating stage is marked by slow and steady decrease in lightning frequency.Despite very high flash rate during the active stage, no severe weather conditions are observed at the ground.It is proposed that the short duration of the active stage might be the reason for the non-observance of severe weather conditions at the ground.Analysis of Skew-t graph at Guwahati suggests that vertical distribution of Convective Available Potential Energy (CAPE)also may play some role in non-occurrence of severe weather at ground in spite of large lightning flash rate and lightning jump observed in this thunderstorm.Further,all electric field changes after a lightning discharge indicates the presence of strong Lower Positive Charge Centers (LPCC)in the active and dissipation stages. This suggests that LPCC plays an important role in initiation of lightning discharges in these stages.

  7. Dancing red sprites and the lightning activity in their parent thunderstorm

    Science.gov (United States)

    Bór, József; Zelkó, Zoltán; Hegedüs, Tibor; Jäger, Zoltán; Mlynarczyk, Janusz; Popek, Martin; Betz, Hans-Dieter

    2016-04-01

    Red sprites are brief optical emissions initiated in the mesosphere by intense tropospheric lightning discharges. A group of red sprites, in which the elements appear in rapid succession with some lateral offset from one another is referred to as a dancing sprite event. The occurrence of such events implies that significant and sequential charge removal extending to large regions of the thunderstorm can take place in the underlying cloud system. In this work, we examine the relation of the locations and observation times of appearing sprite elements to the temporal and spatial distribution of the lightning activity in a specific sprite-active thunderstorm. The selected mesoscale convective system (MCS) composed of several extremely active thundercloud cells crossed Central Europe from South-West to North-East through Germany, Austria, the Czech Republic, and Poland on the night of 6 August, 2013. This MCS has triggered over one hundred sprites including several dancing sprite events. Video recordings of sprites captured from Sopron, Hungary (16.6°E, 47.7°N) and Nydek, Czech Republic (18.8°E, 49.7°N) were used to identify dancing sprite events and to determine the exact locations of the appearing sprite elements by a triangulation technique used originally to analyze meteor observations. Lightning activity in the MCS can be reviewed using the database of LINET lightning detection network which fully covers the region of interest (ROI). The poster demonstrates how cases of sequential charge removal in the thunderstorm can be followed by combining the available information on the occurrence time, location, polarity, and type (CG/IC) of detected lightning strokes in the ROI on one hand and the occurrence time and location of elements in dancing sprite events on the other hand.

  8. Ionospheric Alfvén resonator excitation due to nearby thunderstorms

    Science.gov (United States)

    Surkov, V. V.; Hayakawa, M.; Schekotov, A. Y.; Fedorov, E. N.; Molchanov, O. A.

    2006-01-01

    A theory of midlatitude Ionospheric Alfvén Resonator (IAR) excitation due to random cloud-to-ground lightning discharges is developed. Electromagnetic wave radiated from the lightning discharges penetrates into the ionosphere, thereby exciting the shear Alfvén and magnetosonic waves in the F region of ionosphere. The IAR arises due to wave reflection from the Alfvén velocity gradients in the topside ionosphere. Typically, the ionospheric resonance cavity accumulates the shear Alfvén wave energy with periods from 1 s to a few tenths of seconds. To proceed analytically, a suitably idealized plane-stratified model of the medium was used that ignores the magnetic field line curvature and dip angle but includes plasma conductivity variations with altitude. The thunderstorm centers distributed around a ground-recording station is assumed to be statistically independent sources of the lightning activity, which is a stochastic Poisson process. The lightning onset time and the current moment is supposed to be a random value, while the shape and duration of return strokes are deterministic. Model calculations of the IAR spectrum due to nearby thunderstorm activity were applied to interpret ULF observation made at Karimshino station (52.94°N, 158.25°E) in Kamchatka peninsula. It is shown that the sharp impulses which are in one-to-one correspondence with the appearance of the spectral resonance structure (SRS) in dynamic spectrograms can be the result from nearby lightning discharges followed by impulse IAR excitation. The correlation functions and power spectra of the IAR due to random lightning discharge process is studied both analytically and numerically. We found that the nearby thunderstorms in the range of 1000-2000 km make a main contribution to the SRS signature of the midlatitude IAR, whereas the remote/tropic thunderstorm activity is of minor importance. It is not inconceivable that there may exist other permanent mechanisms of the midlatitude IAR excitation

  9. The influence of artificial-thunderstorm cell polarity on discharge initiation by model hydrometeor arrays

    Science.gov (United States)

    Temnikov, A. G.; Chernenskii, L. L.; Orlov, A. V.; Lysov, N. Yu.; Belova, O. S.; Kalugina, I. E.; Gerastenok, T. K.; Zhuravkova, D. S.

    2017-02-01

    The initiation of discharge by model hydrometeors between an artificial-thunderstorm cell (aerosol cloud) of negative or positive polarity and ground has been experimentally studied. It is established for the first time that the conditions of cloud-ground spark discharge initiation by hydrometeors, as well as the characteristics of discharge significantly depend on the polarity of charged cloud. The effect of hydrometeor arrays can be manifested by the cloud-ground lightning initiated in a thundercloud and used for developing scientific principles of artificial lightning discharge.

  10. A sea breeze induced thunderstorm over an inland station over Indian South Peninsula - A case study

    Science.gov (United States)

    Bhate, Jyoti; Kesarkar, Amit P.; Karipot, Anandakumar; Bala Subrahamanyam, D.; Rajasekhar, M.; Sathiyamoorthy, V.; Kishtawal, C. M.

    2016-10-01

    The dynamic interaction of sea breeze with the prevailing synoptic flows can give rise to meteorological conditions conducive for the occurrence to the thunderstorms over coastal and adjoining regions. Here, we present a rare case study of the genesis of the thunderstorm that occurred on 4th May 2011 at 1500Z over Gadanki (13.5°N, 79.2°E), one of the tropical inland stations (100 km) near to the east coast of the Indian peninsula. The objective of present work is to understand the underlying physical mechanism of initiation of such convection over this region. A set of meteorological observations obtained from microwave radiometer profiler, eddy covariance flux tower system, and Doppler weather radar, are used for investigating the convection genesis characteristics. In conjunction with observations, to bridge the gap of lack of high resolutional spatial observations, the high-resolution (2 km) model analysis is developed using Weather Research and Forecasting (WRF) model and four-dimensional data assimilation technique. The analysis of thermodynamical and dynamical indices carried out from the model analysis as well as observations. Results obtained from this study indicated the presence of a wind discontinuity line and a warm air advection from the north Indian region towards Gadanki caused this area hot dry and convectively active. The sea breeze front propagated over hot and dry area few hours before the genesis of the thunderstorm. The moisture flux convergence increased with the inland propagation of sea breeze front. We found that the inland penetration of sea-breeze front caused advection of moist and cold air over warm and dry region; reduction in dew point depression causing bulging of dry line and lowering of lifting condensation level; development of shear in wind direction and speed; increase in low level convergence and vertical velocity, upward transport of moist air and finally increase in helicity of the environment. The wind shear instability

  11. Long-term variability of the thunderstorm and hail potential in Europe

    Science.gov (United States)

    Mohr, Susanna; Kunz, Michael; Speidel, Johannes; Piper, David

    2016-04-01

    Severe thunderstorms and associated hazardous weather events such as hail frequently cause considerable damage to buildings, crops, and automobiles, resulting in large monetary costs in many parts of Europe and the world. To relate single extreme hail events to the historic context and to estimate their return periods and possible trends related to climate change, long-term statistics of hail events are required. Due to the local-scale nature of hail and a lack of suitable observation systems, however, hailstorms are not captured reliably and comprehensively for a long period of time. In view of this fact, different proxies (indirect climate data) obtained from sounding stations and regional climate models can be used to infer the probability and intensity of thunderstorms or hailstorms. In contrast to direct observational data, such proxies are available homogeneously over a long time period. The aim of the study is to investigate the potential for severe thunderstorms and their changes over past decades. Statistical analyses of sounding data show that the convective potential over the past 20 - 30 years has significantly increased over large parts of Central Europe, making severe thunderstorms more likely. A similar picture results from analyses of weather types that are most likely associated with damaging hailstorms. These weather patterns have increased, even if only slightly but nevertheless statistically significantly, in the time period from 1971 to 2000. To improve the diagnostics of hail events in regional climate models, a logistic hail model has been developed by means of a multivariate analysis method. The model is based on a combination of appropriate hail-relevant meteorological parameters. The output of the model is a new index that estimates the potential of the atmosphere for hailstorm development, referred to as potential hail index (PHI). Applied to a high-resolved reanalysis run for Europe driven by NCEP/NCAR1, long-term changes of the PHI for

  12. Analysis of Summer Thunderstorms in Central Alabama Using the NASA Land Information System

    Science.gov (United States)

    James, Robert; Case, Jonathan; Molthan, Andrew; Jedloved, Gary

    2010-01-01

    Forecasters have difficulty predicting "random" afternoon thunderstorms during the summer months. Differences in soil characteristics could be a contributing factor for storms. The NASA Land Information System (LIS) may assist forecasters in predicting summer convection by identifying boundaries in land characteristics. This project identified case dates during the summer of 2009 by analyzing synoptic weather maps, radar, and satellite data to look for weak atmospheric forcing and disorganized convective development. Boundaries in land characteristics that may have lead to convective initiation in central Alabama were then identified using LIS.

  13. Influence of spring snowpack melting on thunderstorm activity in the Catalan Pyrenees

    Science.gov (United States)

    Pascual, R.; Callado, A.; Terradelles, E.; Téllez, B.

    2009-09-01

    Catalan Pyrenees, the eastern half of the Pyrenees range, is a very popular area for tourism, hiking and climbing. This sector of the range is 200 km long and, on average, 80 km wide. Its highest peaks reach 3000 m ASL and there are many summits above 2500 m ASL. Two of the main climatic characteristics of the region are the very frequent summer convective storms and the late autumn, winter and spring snow-cover. Both characteristics have normally been studied from different points of view, and weather forecasts in late spring have not normally considered the plausible relationship between them. The snowpack melting from April to June, especially rapid in May, leads to important changes on the surface energy balance since the evolution from snow-covered ground to bare soil or canopy, significantly alters the surface albedo and the turbulent, latent and sensible, heat fluxes. These modifications have a noticeable influence in developing or inhibiting thermally-induced mesoscale circulations such as upslope winds, valley breezes or plane-mountain breezes, and could condition the triggering of convection, showers and storm activity. In order to gain insight into the relationship between the spring snowpack melting and the location of thunderstorm activity, a comparison between seasonal snow-cover and thunderstorm frequency evolution (using lightning network data) for a period of 5 years has been carried out, showing a progressive transition from a non-convective to a convective precipitation regime in areas where the snowpack has melted recently Furthermore, a meso-beta scale non-hydrostatic numerical weather prediction model at a 2.5-km horizontal resolution is used to study the sensitivity of snowpack extension on the thunderstorms development over the complex orography of the Catalan Pyrenees. A spring case with thunderstorm activity restricted to snow-free areas has been selected and accurately simulated. A number of sensitivity runs with different initial snow

  14. Response of thunderstorm activity in data of neutron monitoring at Tien Shan

    Science.gov (United States)

    Antonova, Valentina; Kryukov, Sergey; Lutsenko, Vadim

    2015-04-01

    We present results of the study of data of the monitoring of high-energy and thermal neutrons at Tien Shan at different stages of thunderstorm activity. The data of the neutron monitoring were used taking into account the barometric effect. The intensity of the neutron component of cosmic rays is recorded in seven energy ranges. The electric field has values of ~ 100 V/m under fair weather conditions. Standard deviation of minute values of the neutron monitor data at the high altitude station does not exceed 0.5-0.6 %. Found that the standard deviation of the data during thunderstorms always exceeds these values. We selected events during the passage of thunderstorm clouds over the high altitude station without lightning discharges or with a small number of them. It was found that the particle rate of the neutron monitor changes in antiphase with the electric field changes. Atmospheric electric field of positive polarity decreases the count rate of the neutron monitor, and negative polarity - increases. Change of the count rate occurs at values of electric field ≥ 10-15 kV/m and reaches 2 %. The neutron monitor at the high-altitude station has the ability to measure the energy of recorded particles through determination of their multiplicity. We experimentally established that the sensitivity of the detected particles to change in Ez increases with decreasing their energy. The upper energy threshold of sensitivity of neutrons to change electric field is ~10 GeV. The physical mechanism of effect is based on lead nucleus capture of soft negative muons with the subsequent generation of neutrons. It is known that 7% of the neutron monitor count rate caused by negative muons. Absence of this effect in thermal neutrons data confirms the conclusion since the main difference of the thermal neutrons detector from the neutron monitor is the absence of the lead. In the active phase of a thunderstorm in the formed thundercloud the picture of distribution of charges is

  15. Sensitivity of PBL and Cumulus schemes for Thunderstorm prediction over an Indian Region

    Science.gov (United States)

    Kumar, Dinesh; Charan Mohanty, Uma; Kumar, Krishan

    2015-04-01

    The cloud processes play an important role in all forms of precipitation. Its proper representation is one of the challenging tasks in mesoscale numerical simulation. Studies have revealed that mesoscale feature require proper initialization which may likely to improve the convective system rainfall forecasts. Understanding the precipitation process, model initial condition accuracy and resolved/sub grid-scale precipitation processes representation, are the important areas which needed to improve in order to represent the mesoscale features properly. Various attempts have been done in order to improve the model performance through grid resolution, physical parameterizations, etc. But it is the physical parameterizations which provide a convective atmosphere for the development and intensification of convective events. Further, physical parameterizations consist of cumulus convection, surface fluxes of heat, moisture, momentum, and vertical mixing in the planetary boundary layer (PBL). How PBL and Cumulus schemes capture the evolution of thunderstorm have been analysed by taking thunderstorm cases occurred over Kolkata, India in the year 2011. PBL and cumulus schemes were customized for WSM-6 microphysics because WSM series has been widely used in operational forecast. Results have shown that KF (PBL scheme) and WSM-6 (Cumulus Scheme) have reproduced the evolution of surface variable such as CAPE, temperature and rainfall very much like observation. Further, KF and WSM-6 scheme also provided the increased moisture availability in the lower atmosphere which was taken to higher level by strong vertical velocities providing a platform to initiate a thunderstorm much better. Overestimation of rain in WSM-6 occurs primarily because of occurrence of melting and freezing process within a deeper layer in WSM-6 scheme. These Schemes have reproduced the spatial pattern and peak rainfall coverage closer to TRMM observation. It is the the combination of WSM-6, and KF schemes

  16. Investigations into the triggered lightning response of the F106B thunderstorm research aircraft

    Science.gov (United States)

    Rudolph, Terence H.; Perala, Rodney A.; Mckenna, Paul M.; Parker, Steven L.

    1985-01-01

    An investigation has been conducted into the lightning characteristics of the NASA F106B thunderstorm research aircraft. The investigation includes analysis of measured data from the aircraft in the time and frequency domains. Linear and nonlinear computer modelling has also been performed. In addition, new computer tools have been developed, including a new enhanced nonlinear air breakdown model, and a subgrid model useful for analyzing fine details of the aircraft's geometry. Comparison of measured and calculated electromagnetic responses of the aircraft to a triggered lightning environment are presented.

  17. High-Energy Radiation from Thunderstorms with ADELE: TGFs, Steps, and Glows

    Science.gov (United States)

    Smith, David M.; Kelley, Nicole; Martinez-McKinney, Forest; Zhang, Zi Yan; Hazelton, Bryna; Grefenstette, Brian; Splitt, Michael; Lazarus, Steven; Ulrich, William; Levine, Steven; Dwyer, Joseph; Schaal, Meagan; Saleh, Ziad; Cramer, Eric; Rassoul, Hamid; Cummer, Steven; Lu, Gaopeng; Shao, Xuan-Min; Ho, Cheng; Blakeslee, Richard

    2011-01-01

    The biggest challenge in the study of high-energy processes in thunderstorms is getting a detector to the vicinity of the electrically active regions of a storm. The Airborne Detector for Energetic Lightning Emissions (ADELE) has been used to detect gamma rays from aircraft above storms and from a storm-chasing van on the ground. In August 2009, ADELE flew above Florida storms in a Gulfstream V jet, detecting the first terrestrial gamma-ray flash (TGF) seen from a plane and continuous glows of high-energy emission above thunderclouds. The presence of these glows suggests that a gradual process of relativistic runaway and feedback may help limit the total amount of charging in thunderstorms, in contrast to the traditional view that only lightning discharges compete with the charging process. The upper limits on TGF emission from intracloud and cloud-to-ground lightning from the ADELE flights demonstrated conclusively that a TGF of the sort seen from space is not associated with most lightning and not necessary to trigger it. In August 2010, observations from a van detected stepped-leader x-ray emission from at least four lightning strikes in ten days of operations. This mode of operation is therefore promising for future observations of the stepping process, although a more varied suite of instrumentation, in particular a flash-distance detector, would be useful. We will report on these results and on future possibilities for ADELE campaigns.

  18. Characteristics of Preliminary Breakdown Pulses in Positive Ground Flashes during Summer Thunderstorms in Sweden

    Directory of Open Access Journals (Sweden)

    Dalina Johari

    2016-03-01

    Full Text Available This paper presents the characteristics of the preliminary breakdown pulses (PBP in 51 positive ground flashes recorded during 2014 summer thunderstorms in Sweden. Electric field measurements were conducted remotely using a broadband antenna system (up to 100 MHz for a recording length of 1 s with 200 ms trigger time. In the analysis, PBP trains were observed in 86% of the cases. Based on the number of trains preceding the first return stroke, the PBP were classified into single and multiple train PBP. Characteristics of the first PBP train were determined and based on the initial polarity of the pulses, three types of PBP were identified. Characteristics of the subsequent PBP trains in the multiple train PBP were also analyzed and they were compared with the first PBP train. Based on the conceptual charge cloud configuration, we found that the inverted dipole is consistent with our observation. We also found that PBP in positive ground flashes during summer thunderstorms in Sweden are weak since the average ratios of the PBP peak to the first return stroke peak lie only between 0.21 and 0.26. Possible reasons for no detection of PBP and the different types of PBP observed were also discussed.

  19. Space-time simulations of photon, lepton, ionization and nucleon trails of TGF ignition in thunderstorm electric field geometries

    Science.gov (United States)

    Connell, Paul

    2015-04-01

    The origin of high energy electrons which contribute to the Relativistic Runaway Electron Avalanche of a TGF are not precisely known, or yet observed, though the most obvious source would seem to be the products of cosmic ray showers, or electron avalanches generated in the high electric field near the tips of lightning leaders. With our new TGF simulation software package LEPTRACK we can now easily create any electric field geometry to be expected in stormclouds, any kind of electron source, and are investigating scenarios of TGF ignition, which may or may not be runaway, and in any direction - not just vertical. Vidoes, lightcurves and spectra, presenting the detailed density structure and time evolution of TGF photon, electron, neucleon and ionization trails were presented for the first time at the AGU Fall Meeting in 2014 - showing the complicated effects of changing electric field strength and air density - and the as yet unrecognized importance of the earth magnetic field in trapping electrons and positrons in the upper atmosphere at the magnetic equator - possibly giving rise to the hard tail seen in some TGF spectra observed by AGILE. We will present here an extension of this work to show the dynamics of TGF ignition scenarios of current interest - upward, downward and randomly directed - both from free electrons and from combinations of lightning leader micro-fields producing electron avalanches, which are then input to the macro-fields expected at or above thunderstorm cloudtops. We will show the spatial shape and time evolution of TGF particle structures, along with their optical and gamma ray spectra emitted, and bring to life their essential physics.

  20. An isolated tornadic supercell of 14 July 2012 in Poland - A prediction technique within the use of coarse-grid WRF simulation

    Science.gov (United States)

    Taszarek, Mateusz; Czernecki, Bartosz; Walczakiewicz, Szymon; Mazur, Andrzej; Kolendowicz, Leszek

    2016-09-01

    On 14 July 2012 a shortwave trough with a cold front passed through Poland. A few tornadoes were reported in the north central part of the country within an isolated cyclic supercell. The cell moved along the thermal and moisture horizontal gradients and the support of a synoptic scale lift. An analysis allowed for setting up four tornado damage tracks in a distance of 100 km and with a total length of 60 km. Tornadoes damaged 105 buildings with predominant intensity of F1-F2/T3-T4 (maximum F3/T6) in Fujita/TORRO scale, caused 1 fatality, 10 injures and felled 500 hectares of Bory Tucholskie forest. The main aim of this article was to analyze this event and assess the possibilities of its short-term prediction. In order to achieve this, a model forecast data derived from WRF-ARW simulation with a spatial resolution of 15 km and initial conditions extracted from 0000 UTC GFS was used. An analysis yielded that the cell moved in the environment of a low lifting condensation level, rich boundary layer's moisture content and a steepening vertical lapse rates that provided the presence of a thermodynamic instability. A wind vectors tilting with height and an increased vertical wind shear occurred as well. A forecasting method that combined a Universal Tornadic Index composite parameter with a convective precipitation filter showed that convective cells at 1500 UTC in the north central Poland had a potential to become tornadic. Within the use of a proposed methodology, it was possible to issue a tornado forecast for the areas where an index pointed the risk.

  1. Comparison of Thunderstorm Simulations from WRF-NMM and WRF-ARW Models over East Indian Region

    Directory of Open Access Journals (Sweden)

    A. J. Litta

    2012-01-01

    Full Text Available The thunderstorms are typical mesoscale systems dominated by intense convection. Mesoscale models are essential for the accurate prediction of such high-impact weather events. In the present study, an attempt has been made to compare the simulated results of three thunderstorm events using NMM and ARW model core of WRF system and validated the model results with observations. Both models performed well in capturing stability indices which are indicators of severe convective activity. Comparison of model-simulated radar reflectivity imageries with observations revealed that NMM model has simulated well the propagation of the squall line, while the squall line movement was slow in ARW. From the model-simulated spatial plots of cloud top temperature, we can see that NMM model has better captured the genesis, intensification, and propagation of thunder squall than ARW model. The statistical analysis of rainfall indicates the better performance of NMM than ARW. Comparison of model-simulated thunderstorm affected parameters with that of the observed showed that NMM has performed better than ARW in capturing the sharp rise in humidity and drop in temperature. This suggests that NMM model has the potential to provide unique and valuable information for severe thunderstorm forecasters over east Indian region.

  2. A weather analysis of strong winds and hail developed by a supercell with a bow echo%一次弓形回波中超级单体发展造成的大风、冰雹天气分析

    Institute of Scientific and Technical Information of China (English)

    吴哲红; 陈贞宏; 储丽君; 冯新建

    2012-01-01

    Weakened,a back weak echo channel feature appeared,In the weak echo channel the supercell produce tornadoes which caused downburst winds disaster caused in maoying town in ziyun county.The two strong wind disasters developed at different stages of convective systems,the mechanisms are different.

  3. parameterrization of microphysical and dynamical processes of rainfall in thunderstorm cloud model

    Directory of Open Access Journals (Sweden)

    S. J.

    2002-12-01

    Full Text Available   In this research parameterization of the precipitation process in Ogura & Takahashi (O-T thunderstorm model was improved in microphysical processes, specially in the autoconversion process to form raindrops, in the glaciation process and in the terminal velocities of rain and hail. The rainfall intensity became much heavier with Kesslers parameterization, the second peak of the rainfall intensity disappeared with Biggs freezing probability, and the rainfall intensity became much heavier and sharper with Lin et als terminal velocities of rain and hail than in the O-T original model. Finally, the derived rainfall pattern based on the improved model has much similarities to the observation data. This paper expresses the basic research for studying the physical treatment in clouds. The modified O-T model has different applications in analyzing radar observation data, estimate the potential of soil erosion, parameteriztion of shower in mesoscale numerical weather prediction and eta.

  4. High-Altitude Aircraft-Based Electric-Field Measurements Above Thunderstorms

    Science.gov (United States)

    Bateman, M. G.; Blakeslee, R. J.; Bailey, J. C.; Stewart, M. F.; Blair, A. K.

    1999-01-01

    We have developed a new set of eight electric field mills that were flown on a NASA ER-2 high-altitude aircraft. During the Third Convection And Moisture EXperiment (CAMEX-3; Fall, 1998), measurements of electric field, storm dynamics, and ice microphysics were made over several hurricanes. Concurrently, the TExas-FLorida UNderflights (TEFLUN) program was being conducted to make the same measurements over Gulf Coast thunderstorms. Sample measurements are shown: typical flight altitude is 20km. Our new mills have an internal 16-bit A/D, with a resolution of 0.25V/m per bit at high gain, with a noise level less than the least significant bit. A second, lower gain channel gives us the ability to measure fields as high as 150 kV/m.

  5. TETRA Observation of Gamma Rays at Ground Level Associated with Nearby Thunderstorms

    CERN Document Server

    Ringuette, Rebecca; Cherry, Michael L; Granger, Douglas; Guzik, T Gregory; Stewart, Michael; Wefel, John P

    2013-01-01

    Terrestrial Gamma ray Flashes (TGFs) -- very short, intense bursts of electrons, positrons, and energetic photons originating from terrestrial thunderstorms -- have been detected with satellite instruments. TETRA, an array of NaI(Tl) scintillators at Louisiana State University, has now been used to detect similar bursts of 50 keV to over 2 MeV gamma rays at ground level. After 2.6 years of observation, twenty-four events with durations 0.02- 4.2 msec have been detected associated with nearby lightning, three of them coincident events observed by detectors separated by ~1000 m. Nine of the events occurred within 6 msec and 3 miles of negative polarity cloud-to-ground lightning strokes with measured currents in excess of 20 kA. The events reported here constitute the first catalog of TGFs observed at ground level in close proximity to the acceleration site.

  6. Signatures of thunderstorms in the variations of the secondary cosmic rays registered in Mexico City

    Science.gov (United States)

    Alvarez-Castillo, J.; Valdés-Galicia, J. F.

    2010-01-01

    We studied the effect of thunderstorms (TS) in the intensity variations of the electromagnetic and muon components of the Cosmic Rays during the year 2004, a year of minimum solar activity. We analyzed the variations in the counting rates of the upper and lower scintillators of the muon telescope installed in Mexico City at times of reported TS and compared those with variations during quiet times. The data were filtered to eliminate long trends, then a wavelet spectrum was calculated, searching for the temporal evolution of diverse periods of high significance; recurrent periodicities and total power distributions were obtained. The results show variations of short period whose main periodicities are arranged in a distribution where the most important are the shortest periodicities. These may be associated to the electric fields of the TS. Significant long period variations were found too, these could be due to other processes linked to rainstorms. No systematic effect on the power of variations due to TS was found.

  7. Static Electric Fields and Lightning Over Land and Ocean in Florida Thunderstorms

    Science.gov (United States)

    Wilson, J. G.; Cummins, K. L.; Simpson, A. A.; Hinckley, A.

    2017-01-01

    Natural cloud-to-ground (CG) lightning and the charge structure of the associated clouds behave differently over land and ocean. Existing literature has raised questions over the years on the behavior of thunderstorms and lightning over oceans, and there are still open scientific questions. We expand on the observational datasets by obtaining identical electric field observations over coastal land, near-shore, and deep ocean regions during both clear air and thunderstorm periods. Oceanic observations were obtained using two 3-meter NOAA buoys that were instrumented with Campbell Scientific electric field mills to measure the static electric fields. These data were compared to selected electric field records from the existing on-shore electric field mill suite of 31 sensors at Kennedy Space Center (KSC). CG lightning occurrence times, locations and peak current values for both on-shore and ocean were provided by the U.S. National Lightning Detection Network. The buoy instruments were first evaluated on-shore at the Florida coast, to calibrate field enhancements and to confirm proper behavior of the system in elevated-field environments. The buoys were then moored 20NM and 120NM off the coast of KSC in February (20NM) and August (120NM) 2014. Statistically larger CG peak currents were reported over the deep ocean for first strokes and for subsequent strokes with new contacts points. Storm-related static fields were significantly larger at both oceanic sites, likely due to decreased screening by nearby space charge. Time-evolution of the static field during storm development and propagation indicated weak or missing lower positive charge regions in most storms that initiated over the deep ocean, supporting one mechanism for the observed high peak currents in negative first strokes over the deep ocean. This project also demonstrated the practicality of off-shore electric field measurements for safety-related decision making at KSC.

  8. Satellite-based technique for nowcasting of thunderstorms over Indian region

    Indian Academy of Sciences (India)

    Suman Goyal; Ashish Kumar; M Mohapatra; L S Rathore; S K Dube; Rahul Saxena; R K Giri

    2017-08-01

    India experiences severe thunderstorms during the months, March–June. But these systems are not predicted well, mainly due to the absence of mesoscale observational network over Indian region and the expert system. As these are short lived systems, the nowcast is attempted worldwide based on satellite and radar observations. Due to inadequate radar network, satellite plays the dominant role for nowcast of these thunderstorms. In this study, a nowcast based algorithm ForTracc developed by Vila et al. (Weather Forecast 23:233–245, 2008) has been examined over the Indian region using Infrared Channel (10.8 μm) of INSAT-3D for prediction of Mesoscale Convective Systems (MCS). In this technique, the current location and intensity in terms of Cloud Top Brightness Temperature (CTBT) of the MCS are extrapolated. The purpose of this study is to validate this satellite-based nowcasting technique for Convective Cloud Clusters that helps in optimum utilization of satellite data and improve the nowcasting. The model could predict reasonably the minimum CTBT of the convective cell with average absolute error (AAE) of <7 K for different lead periods (30–180 min). However, it was underestimated for all the lead periods of forecasts. The AAE in the forecasts of size of the cluster varies from about 3×104 km2 for 30-min forecast to 7×104 km2 for 120-min forecast. The mean absolute error in prediction of size is above 31–38% of actual size for different lead periods of forecasts from 30 to 180 min. There is over estimation in prediction of size for 30 and 60 min forecasts (17% and 2.6% of actual size of the cluster, respectively) and underestimation in 90 to 180-min forecasts (–2.4% to –28%). The direct position error (DPE) based on the location of minimum CTBT ranges from 70 to 144 km for 30–180-min forecast respectively.

  9. Artificially triggered lightning and its characteristic discharge parameters in two severe thunderstorms

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The lightning-induced-damages in the mid-latitude regions are usually caused during severe thunder-storms. But the discharge parameters of natural lightning are difficult to be measured. Five lightning flashes have been artificially triggered with the rocket-wire technique during the passage of two severe thunderstorms. The discharge current and close electric field of return stroke in artificially triggered lightning have been obtained in microsecond time resolution by using current measuring systems and electric field change sensors. The results show that the five triggered lightning flashes include 1 to 10 return strokes, and the average return stroke current is 11.9 kA with a maximum of 21.0 kA and a mini-mum of 6.6 kA, similar to the subsequent return strokes in natural lightning. The half peak width of the current waveform is 39 μs, which is much larger than the usual result. The peak current of stroke Ip (kA) and the neutralized charge Q(C) has a relationship of Ip = 18.5Q0.65. The radiation field of return stroke is 5.9 kV·m-1 and 0.39 kV·m-1 at 60 m and 550 m, respectively. The radiation field decreases as r -1.119 with increase of horizontal distance r from the discharge channel. Based on the well-accepted transmission line model, the speed of return stroke is estimated to be about 1.4×108 m·s-1, with a variation range of (1.1―1.6)×108 m·s-1. Because of the similarities of the triggered lightning and natural lightning, the results in this article can be used in the protection design of natural lightning.

  10. Electrical measurements in the atmosphere and the Ionosphere over an active thunderstorm. II - Direct current electric fields and conductivity

    Science.gov (United States)

    Holzworth, R. H.; Kelley, M. C.; Siefring, C. L.; Hale, L. C.; Mitchell, J. D.

    1985-01-01

    On August 9, 1981, a series of three rockets was launched over an air mass thunderstorm off the eastern seaboard of Virginia while simultaneous stratospheric and ground-based electric field measurements were made. The conductivity was substantially lower at most altitudes than the conductivity profiles used by theoretical models. Direct current electric fields over 80 mV/m were measured as far away as 96 km from the storm in the stratosphere at 23 km altitude. No dc electric fields above 75 km altitude could be identified with the thunderstorm, in agreement with theory. However, vertical current densities over 120 pA/sq m were seen well above the classical 'electrosphere' (at 50 or 60 km). Frequent dc shifts in the electric field following lightning transients were seen by both balloon and rocket payloads. These dc shifts are clearly identifiable with either cloud-to-ground (increases) or intercloud (decreases) lightning flashes.

  11. Positive Charge Region in Lower Part of Thunderstorm and Preliminary Breakdown Process of Negative Cloud-to-Ground Lightning

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yijun; MENG Qing; LU Weitao; MA Ming; ZHENG Dong; Pau R. Krehbiel

    2009-01-01

    A new lightning locating technology, called Lightning Mapping Array (LMA), has been developed. The system takes advantage of GPS technology to measure the times of arrival (TOA) of lightning impulsive very high frequency (VHF) radiation events at each remote location. The spatiotemporal development processes of lightning are described in three-dimension by measurement of the system with high time resolution (50 ns) and space precision (50-100 m). The charge structures in thunderstorm and their relationship with lightning discharge processes are revealed. The temporal and spatial characteristics of preliminary breakdown process involved in negative cloud-to-ground (CG) lightning discharges are analyzed based on the data of lightning VHF radiation events. The effect of positive charge region in lower part of thunderstorm on the occurrence of negative CG lightning discharge is discussed. The results indicate that the preliminary breakdown process with longer duration in negative CG lightning discharges is an intracloud discharge process. It occurs between negative and positive charge regions located in middle and lower parts of thunderstorm respectively.It initiates from the negative charge region and propagates downward. After propagating into the positive charge region, the lightning channel develops horizontally. The characteristics of the preliminary breakdown process are consistent with that of intracloud lightning discharges. The stepped leaders are initiated by the K type breakdown which occurs in the last stage of the preliminary breakdown process and develops downward through the positive charge region. The existence of positive charge region in lower part of thunderstorm results in the occurrence of preliminary breakdown process with longer duration before the return stroke of negative CG lightning discharges.

  12. Simulating High Lightning Flash Rates at Upper Levels in Strong and Severe Thunderstorms

    Science.gov (United States)

    Mansell, E.

    2015-12-01

    Lightning mapping systems have detected high lightning flash rates at the top of convective cores above the environmental -30°C level, particularly in severe storms. Previous 3-D model simulations have reproduced similarly high flash rates using bulk (one or two moment) microphysics, but the details of the charge separation were not closely examined. Recent work has raised questions as to whether the charging processes have been adequately simulated, both in terms of grid resolution and microphysical processes. New simulations of a severe supercell storm with Takahashi spectral bin microphysics and 4x better grid resolution (250m horizontal and 125 vertical spacing) are better able to capture the steep vertical temperature gradients (on the order of 8°C per km) and the process of freezing of larger liquid particles. The results suggest that high charge separation rates can occur as larger drops freeze homogeneously while smaller droplets remain liquid. This process far outstrips other small ice particle production processes like vapor nucleation or ice multiplication. This intense and vertically narrow charging zone then leads to sufficiently fast electric field growth that favors smaller flashes. These results form the hypothesis that high rates of spatially small lightning flashes result from a high density charging current in a relatively small volume, such that initiation electric field thresholds are met quickly before larger net charge regions have time to form. Results will also be presented for bulk microphysics with an updated droplet freezing scheme that emulates the freezing of droplets based on diameter and ambient temperature. An important consideration in both schemes is how to handle newly-freezing droplets in the calculation of riming rate (or cloud water content) in the charge separation rate equations.

  13. Detailed flow, hydrometeor and lightning characteristics of an isolated thunderstorm during COPS

    Directory of Open Access Journals (Sweden)

    K. Schmidt

    2012-04-01

    Full Text Available The three-hour life-cycle of the isolated thunderstorm on 15 July 2007 during the Convective and Orographically-induced Precipitation Study (COPS is documented in detail, with a special emphasis on the rapid development and mature phases. Remote sensing techniques as 5-min rapid scans from geostationary satellites, combined velocity retrievals from up to four Doppler-radars, the polarimetric determination of hydrometeors and spatio-temporal occurrences of lightning strokes are employed to arrive at a synoptic quantification of the physical parameters of this, during the COPS period, rare event.

    Inner cloud flow fields are available from radar multiple Doppler analyses, gridded on a 500 m-mesh, at four consecutive times separated by 15 min-intervals (14:35, 14:50, 15:05, 15:20; all times are in UTC. They contain horizontal winds of around 15 m s−1 and updrafts exceeding 5 m s−1, the latter collocated with lightning strokes. Reflectivity and polarimetric data indicate the existence of hail at the 2 km level around 14:40. Furthermore, polarimetric and Doppler radar variables indicate intense hydrometeor variability and cloud dynamics corresponding to an enhanced variance of the retrieved 3-D wind fields. Profiles of flow and hydrometeor statistics over the entire cloud volume provide reference data for high-resolution, episode-type numerical weather prediction runs in research mode.

    The study embarks from two multi-channel time-lapse movie-loops from geostationary satellite imagery (as Supplement, which provide an intuitive distinction of six phases making up the entire life-cycle of the thunderstorm. It concludes with a triple image-loop, juxtaposing a close-up of the cloud motion as seen by Meteosat, simulated brightness temperature (as a proxy for clouds seen by the infrared satellite channel, and a perspective view on the model generated system of cloud cells. By employing the motion-geared human

  14. LEONA: Transient Luminous Event and Thunderstorm High Energy Emission Collaborative Network in Latin America

    Science.gov (United States)

    Sao Sabbas, F. T.

    2012-12-01

    This project has the goal of establishing the Collaborative Network LEONA, to study the electrodynamical coupling of the atmospheric layers signaled by Transient Luminous Events - TLEs and high energy emissions from thunderstorms. We will develop and install a remotely controlled network of cameras to perform TLE observations in different locations in South America and one neutron detector in southern Brazil. The camera network will allow building a continuous data set of the phenomena studied in this continent. The first two trial units of the camera network are already installed, in Brazil and Peru, and two more will be installed until December 2012, in Argentina and Brazil. We expect to determine the TLE geographic distribution, occurrence rate, morphology, and possible coupling with other geophysical phenomena in South America, such as the South Atlantic Magnetic Anomaly - SAMA. We also expect to study thunderstorm neutron emissions in a region of intense electrical activity, measuring neutron fluxes with high time resolution simultaneously with TLEs and lightning for the first time in South America. Using an intensified high-speed camera for TLE observation during 2 campaigns we expect to be able to determine the duration and spatial- temporal development of the TLEs observed, to study the structure and initiation of sprites and to measure the velocity of development of sprite structures and the sprite delay. The camera was acquired via the FAPESP project DEELUMINOS (2005-2010), which also nucleated our research group Atmospheric Electrodynamical Coupling - ACATMOS. LEONA will nucleate this research in other institutions in Brazil and other countries in South America, providing continuity for this important research in our region. The camera network will be an unique tool to perform consistent long term TLE observation, and in fact is the only way to accumulate a data set for a climatological study of South America, since satellite instrumentation turns off in

  15. The Angular Distribution of Electron and X-ray Emission from Triggered Lightning Leader Steps Using the Thunderstorm Energetic Radiation Array (TERA)

    Science.gov (United States)

    Schaal, M.; Dwyer, J. R.; Rassoul, H. K.; Uman, M. A.; Jordan, D. M.; Hill, J. D.

    2012-12-01

    Energetic radiation is known to be produced by thunderclouds and lightning. To investigate the characteristics of these emissions, ground-based observations are being conducted at the International Center for Lightning Research and Testing (ICLRT) at Camp Blanding, FL. Measurements of the electric and magnetic fields, optical emissions, and energetic radiation from both natural and rocket-triggered lightning discharges are recorded at the ICLRT. Specifically, the Thunderstorm Energetic Radiation Array (TERA) is used to measure x-ray and gamma-ray emissions. In total, the ICLRT encompasses 36 NaI and two LaBr3 PMTs as part of TERA. Additionally, these measurements were compared with Monte Carlo simulations of runaway electron propagation and their x-ray emission with the goal of understanding the underlying mechanism of runaway electron production and their role in lightning initiation and propagation. In this study, we investigate individual leader steps to determine if electrons at the source (and hence x-rays) are emitted isotropically or with some degree of anisotropy. This study is motivated by the work of Saleh et al. 2009, which compared distributions of a beamed and an isotropic electron source to radial energy distributions using TERA and determined that the average electron source of emission was isotropic. The anisotropy of the runaway electrons is important because it may provide information on the electric fields near the lightning leader tip.

  16. Prevention of destructive tropical and extratropical storms, hurricanes, tornadoes, dangerous thunderstorms, and catastrophic floods

    Directory of Open Access Journals (Sweden)

    E. Yu. Krasilnikov

    2002-01-01

    Full Text Available Tropical cyclones and storms, hurricanes, powerful thunderclouds, which generate tornadoes, destructive extratropical cyclones, which result in catastrophic floods, are the powerful cloud systems that contain huge amount of water. According to the hypothesis argued in this paper, an electric field coupled with powerful clouds and electric forces play a cardinal role in supporting this huge mass of water at a high altitude in the troposphere and in the instability of powerful clouds sometimes during rather a long time duration. Based on this hypothesis, a highly effective method of volume electric charge neutralization of powerful clouds is proposed. It results in the decrease in an electric field, a sudden increase in precipitation, and subsequent degradation of powerful clouds. This method, based on the natural phenomenon, ensures the prevention of the intensification of tropical and extratropical cyclones and their transition to the storm and hurricane (typhoon stages, which makes it possible to avoid catastrophic floods. It also ensures the suppression of severe thunderclouds, which, in turn, eliminates the development of dangerous thunderstorms and the possibility of the emergence and intensification of tornadoes.

  17. An operational approach to the nowcasting of an intense thunderstorm over Liguria

    Directory of Open Access Journals (Sweden)

    S. Gallino

    2006-01-01

    Full Text Available In the period between late spring and early summer as well as in autumn, the Mediterranean is often affected by rapid development of intense convective systems. In some cases the operational NWP models are able to provide good indication of occurrence of such severe weather events (potential instability conditions but often location and intensity of convective precipitation are poorly forecasted. The approach of "PV-thinking" revealed itself as a good tool to identify favorable conditions for triggering such systems, partially filling this lack of information and supporting meteorologists in the very short range weather forecast. Moreover, the advanced use of data provided by SEVIRI channels onboard MSG satellite, makes possible an effective application of the PV approach, improving forecast skill also in areas where local effects are not well described by the models and/or by the data assimilation. The aim of this work is to show how the application of the MSG tools together with the PV philosophy helps in the diagnosis and nowcasting of intense thunderstorms triggered by tropopause, with particular attention to a case of intense convection over northwestern Italy during spring 2005.

  18. Impact of updraft on neutralized charge rate by lightning in thunderstorms: A simulation case study

    Science.gov (United States)

    Wang, Fei; Zhang, Yijun; Zheng, Dong

    2015-12-01

    The rate of neutralized charge by lightning (RNCL) is an important parameter indicating the intensity of lightning activity. The total charging rate (CR), the CR of one kind of polarity (e.g., negative) charge (CROP), and the outflow rate of charge on precipitation (ORCP) are proposed as key factors impacting RNCL, based on the principle of conservation of one kind of polarity charge in a thunderstorm. In this paper, the impacts of updraft on CR and CROP are analyzed by using a 3D cloud resolution model for a strong storm that occurred in Beijing on 6 september 2008. The results show that updraft both promotes and inhibits RNCL at the same time. (1) Updraft always has a positive influence on CR. The correlation coefficient between the updraft volume and CR can reach 0.96. Strengthening of the updraft facilitates strengthening of RNCL through this positive influence. (2) Strengthening of the updraft also promotes reinforcement of CROP. The correlation coefficient between the updraft volume and CROP is high (about 0.9), but this promotion restrains the strengthening of RNCL because the strengthening of CROP will, most of the time, inhibit the increasing of RNCL. (3) Additionally, increasing of ORCP depresses the strengthening of RNCL. In terms of magnitude, the peak of ORCP is equal to the peak of CR. Because precipitation mainly appears after the lightning activity finishes, the depression effect of ORCP on RNCL can be ignored during the active lightning period.

  19. A reconstruction of 1 August 1674 thunderstorms over the Low Countries

    Science.gov (United States)

    van der Schrier, Gerard; Groenland, Rob

    2017-02-01

    On 1 August 1674 an active cold front moved over the Low Countries. The accompanying thunderstorms along the squall line were abnormally active, leading to large-scale damage in Europe, from northern France to the northern parts of Holland where damages were particularly severe. Using reported and pictured observations of damages and modern meteorological concepts, the reconstruction of the storm points to an exceptionally severe squall line. The orientation and the velocity of the squall line are reconstructed and shows a developed bow-echo structure. An estimate of the strength of the strongest wind gusts is ≈ 55-90 m s-1 and is based on an assessment of the damages caused by this event. A rough estimate of the return time of this event, based on observed hail size, is between 1000 and 10 000 years. This storm is compared to a more recent storm which was similar in dynamics but much less devastating. Special attention is given to the city of Utrecht which was hit hardest, and where the impact of this storm is still recognizable in the cityscape.

  20. Climatic Characteristics of Thunderstorm Gale in Langfang of Hebei Province%河北廊坊雷暴大风的气候特征

    Institute of Scientific and Technical Information of China (English)

    周贺玲; 张绍恢; 杨艳

    2014-01-01

    Based on the observational data of 9 meteorological stations in Langfang of Heibei Province during 1970-2012,the temporal and spatial characteristics,change trends and cycle of thunderstorm gale were analyzed by using trend analysis,moving t test,wavelet analysis and maximum entropy spectrum.Results showed that thunderstorm gale in Langfang mostly occurred at one station,while the whole regional thunderstorm gale appeared only once.Thus,the thunderstorm gales had strong local feature.The regional characteristic of thunderstorm gale was obvious,and thunderstorm gale days in We’nan and Dacheng as well as Langfang city were more,while they were least in the north of Langfang.The daily,monthly and annual variation of thunderstorm gale days were significant.The thunder-storm and gale mostly happened from afternoon to midnight,and the occurring time of gale was later than that of thunderstorm general-ly.The frequencies of thunderstorms lasting about 1 hour and gales lasting 10 minutes were the most.The thunderstorm gale weathers occur from March to October,especially in summer,and the occurring frequency is 73.3%.In the past 43 years,the days of thunder-storm gale decreased significantly,and the decreasing trends at stations in the middle of Langfang were the most significant.The muta-tion of thunderstorm gale days occurred in 1994,and the significant period was 3.23 years.%利用1970~2012年廊坊地区9个气象站地面雷暴大风观测资料,采用趋势分析、滑动t检验、小波分析和最大熵谱分析等统计方法,系统分析了该地区雷暴大风天气的时空特征及变化趋势和变化周期。结果表明:廊坊地区的雷暴大风局地性强,43 a间只出现了一次全区性的雷暴大风天气过程,雷暴大风多以单站出现为主。雷暴大风的地域性特征明显,中部的廊坊市及南部的文安、大城站较易出现,而北部发生概率较低。雷暴大风的日、月及年变化特征明显。雷暴

  1. Low-Level Polarimetric Radar Signatures in EnKF Analyses and Forecasts of the May 8, 2003 Oklahoma City Tornadic Supercell: Impact of Multimoment Microphysics and Comparisons with Observation

    Directory of Open Access Journals (Sweden)

    Daniel T. Dawson II

    2013-01-01

    Full Text Available The impact of increasing the number of predicted moments in a multimoment bulk microphysics scheme is investigated using ensemble Kalman filter analyses and forecasts of the May 8, 2003 Oklahoma City tornadic supercell storm and the analyses are validated using dual-polarization radar observations. The triple-moment version of the microphysics scheme exhibits the best performance, relative to the single- and double-moment versions, in reproducing the low-ZDR hail core and high-ZDR arc, as well as an improved probabilistic track forecast of the mesocyclone. A comparison of the impact of the improved microphysical scheme on probabilistic forecasts of the mesocyclone track with the observed tornado track is also discussed.

  2. The Influence of the Electric Field on Thunderstorm Microphysical Development Simulated with an Explicit Microphysics Model

    Science.gov (United States)

    Phillips, V. T.; Andronache, C.; Sherwood, S.

    2005-05-01

    Electric fields influence the microphysics of aerosol-cloud interactions. Hence, nucleation of ice is sensitive to the charge on nuclei. Furthermore, there is an increase in the collision efficiency when charged aerosol particles collide with droplets ('electroscavenging'), and rates of contact ice nucleation are enhanced by the charge on aerosol particles (Tinsley et al. 2000, Tripathi and Harrison, 2002). In addition, electric fields (EF) affect the collisional growth rate of hydrometeors and their fall velocity. The aim here is to assess how the collection efficiency for the coagulation of hydrometeors may be modified by a typical EF in a thunderstorm. Particular focus is given to effects on the generation of anvil ice particles. This is done by imposing a realistic EF in the control simulation with an Explicit Microphysics Model (EMM) of the storm, observed on 18th July 2002 near Florida during the Cirrus Regional Study of Tropical Anvils and Cirrus Layers - Florida Area Cirrus Experiment (CRYSTAL-FACE), as described by Phillips et al. (2005). An additional aim is to analyze how updraft speed (w) and environmental CCN concentration may affect the charge separation process. The warm rain process is intensified and there is a 30-40% reduction in the anvil ice concentration when an evolving height-dependent EF, typical of continental electrified thunderstorms, is prescribed and applied to the collection efficiencies for coagulation processes in the model. The electric dependence of the collision efficiency for drop-drop collisions is the cause. There is a 150% increase in the broad peak of average mixing ratio of rain near the freezing level (see Figure 1). This boosts the mixing ratio of precipitation-sized ice in the lower half of the mixed phase region, changing the number of charging collisions and depleting the supercooled cloudwater. Primarily because of the high sensitivity of the Hallett-Mossop (H-M) process of ice particle multiplication with respect to

  3. Initial electrification to the first lightning flash in New Mexico thunderstorms

    Science.gov (United States)

    Stolzenburg, Maribeth; Marshall, Thomas C.; Krehbiel, Paul R.

    2015-11-01

    The initial electrification of three New Mexico thunderstorms is examined using in situ and remote measurements. The earliest deflection of electric field (E) measured at the surface was 5-8.6 min before the first flash and coincident with the development of substantial radar reflectivity (40 dBZ) above -5°C. Rapid growth of surface E (>5 V/m/s) started 2.4-3.1 min before the first flash, when 40 dBZ reflectivities reached above the -15°C level. In two cases with clear surface E records, radar reflectivity indicators (40 dBZ echo through -10°C and echo top through -15°C) would yield longer warning times before the first flash than the E record. The first flash in each storm initiated at altitudes between 7.4 and 8.8 km; hence, the temperatures where the largest (negative) E for normal intracloud lightning initiation had developed during the initial electrification were -10°C to -20°C. Negative and positive charge regions associated with the first flash in each cell were centered at -8°C to -16°C (6.9-8.0 km) and -20°C to -24°C (9.0-9.2 km), respectively. In two cases, balloon data indicate the only substantial charge regions present before the first flash were those involved in the flash. Another case shows an initial period of opposite polarity E deflection at the surface coincident with substantial low-level positive charge within the cloud, although this charge was not involved in the first 8 min (first 17 flashes) of lightning activity. The findings support the notion that the initial electrification resulted from charging via the noninductive ice-ice collisional mechanism.

  4. Thunderstorm and stratocumulus: how does their contrasting morphology affect their interactions with aerosols?

    Directory of Open Access Journals (Sweden)

    S. S. Lee

    2010-07-01

    Full Text Available It is well-known that aerosols affect clouds and that the effect of aerosols on clouds is critical for understanding human-induced climate change. Most climate model studies have focused on the effect of aerosols on warm stratiform clouds (e.g., stratocumulus clouds for the prediction of climate change. However, systems like the Asian and Indian Monsoon, storm tracks, and the intertropical convergence zone, play important roles in the global hydrological cycle and in the circulation of energy and are driven by thunderstorm-type convective clouds. Here, we show that the different morphologies of these two cloud types lead to different aerosol-cloud interactions. Increasing aerosols are known to suppress the conversion of droplets to rain (i.e., so-called autoconversion. This increases droplets as a source of evaporative cooling, leading to an increased intensity of downdrafts. The acceleration of the intensity of downdrafts is larger in convective clouds due to their larger cloud depths (providing longer paths for downdrafts to follow to the surface than in stratiform clouds. More accelerated downdrafts intensify the gust front, leading to significantly increased updrafts, condensation and thus the collection of cloud liquid by precipitation, which offsets the suppressed autoconversion. This leads to an enhancement of precipitation with increased aerosols in convective clouds. However, the downdrafts are less accelerated in stratiform clouds due to their smaller cloud depths, and they are not able to induce changes in updrafts as large as those in convective clouds. Thus, the offset is not as effective, and this allows the suppression of precipitation with increased aerosols. Thus aerosols affect these cloud systems differently. The dependence of the effect of aerosols on clouds on the morphology of clouds should be taken into account for a more complete assessment of climate change.

  5. Duration and extent of large electric fields in a thunderstorm anvil cloud after the last lightning

    Science.gov (United States)

    Stolzenburg, Maribeth; Marshall, Thomas C.; Krehbiel, Paul R.

    2010-10-01

    A series of balloon electric field (E) soundings and time-correlated radar scans through the balloon locations are used to examine the evolution of charge and reflectivity inside a dissipating thunderstorm anvil. The soundings cover a 75 min period during and after the final lightning flash in distant convection. The first sounding measured large E magnitudes (maximum 65 kV m-1) and significant charge densities of both polarities (maximum +2.5 nC m-3) within and screening the anvil. Little change in the maximum E values occurred in the 30 min between the first and third soundings, although altitudes and densities of some charge regions decreased with time (maximum +0.6 nC m-3). Screening charge regions were observed in close coincidence with 12 dbZ radar reflectivity contours, and interior positive charge was found in the reflectivity maxima of both anvil decks. The fourth sounding ascended through visible but optically less dense cloud, and no enhanced E values were detected. Overall, the data indicate the interior positive charge region of the main anvil contained about 150 C and covered at least 250 km2 nearly 30 min after the last lightning flash. Potentially hazardous E values of 30-35 kV m-1 were measured at 9.9-10.2 km altitude, a common jet aircraft cruising altitude, more than 20 km away from and 32 min after the final lightning flash. About 50 min after the last flash, the main positive charge region contained an estimated 50 C, and potentially hazardous E values associated with the anvil extended over at least 220 km2.

  6. Map showing alpine debris flows triggered by a July 28, 1999 thunderstorm in the central Front Range of Colorado

    Science.gov (United States)

    Godt, Jonathan W.; Coe, Jeffrey A.

    2003-01-01

    This 1:24,000-scale map shows an inventory of debris flows that were triggered above timberline by a thunderstorm in the central Front Range of Colorado. We have classified the debris flows into two categories based on the style of initiation processes in the debris-flow source areas: 1) soil slip, and 2) non-soil slip erosive processes. This map and associated digital data are part of a larger study of the debris-flow event, results of which we plan to present in a forthcoming paper.

  7. Range estimation techniques in single-station thunderstorm warning sensors based upon gated, wideband, magnetic direction finder technology

    Science.gov (United States)

    Pifer, Alburt E.; Hiscox, William L.; Cummins, Kenneth L.; Neumann, William T.

    1991-01-01

    Gated, wideband, magnetic direction finders (DFs) were originally designed to measure the bearing of cloud-to-ground lightning relative to the sensor. A recent addition to this device uses proprietary waveform discrimination logic to select return stroke signatures and certain range dependent features in the waveform to provide an estimate of range of flashes within 50 kms. The enhanced ranging techniques are discussed which were designed and developed for use in single station thunderstorm warning sensor. Included are the results of on-going evaluations being conducted under a variety of meteorological and geographic conditions.

  8. Lightning to the upper atmosphere: A vertical light pulse from the top of a thunderstorm as seen by a payload bay TV camera of the space shuttle

    Science.gov (United States)

    Boeck, William L.; Vaughan, Otha H., Jr.; Blakeslee, Richard; Vonnegut, Bernard; Brook, Marx; Mckune, John

    1991-01-01

    An examination and preliminary analysis of video images of thunderstorms as seen by a payload bay TV camera of the Space Shuttle provided examples of lightning in the stratosphere above thunderstorms. These images were obtained on several recent Shuttle flights while conducting the Mesoscale Lightning Experiment (MLE). MLE was an experiment to obtain night time images from space of large storm complexes with lightning. These images are used to provide data for the design of specialized instrumentation which will provide quantitative measurements of global lightning. Eight video sequences were selected because they illustrate near vertical discharges in the stratosphere above thunderstorms. Although there are previous reports in the literature, these are the first images from the viewpoint of an orbiting spacecraft. The written material is primarily a companion to a video presentation.

  9. Automated information-analytical system for thunderstorm monitoring and early warning alarms using modern physical sensors and information technologies with elements of artificial intelligence

    Science.gov (United States)

    Boldyreff, Anton S.; Bespalov, Dmitry A.; Adzhiev, Anatoly Kh.

    2017-05-01

    Methods of artificial intelligence are a good solution for weather phenomena forecasting. They allow to process a large amount of diverse data. Recirculation Neural Networks is implemented in the paper for the system of thunderstorm events prediction. Large amounts of experimental data from lightning sensors and electric field mills networks are received and analyzed. The average recognition accuracy of sensor signals is calculated. It is shown that Recirculation Neural Networks is a promising solution in the forecasting of thunderstorms and weather phenomena, characterized by the high efficiency of the recognition elements of the sensor signals, allows to compress images and highlight their characteristic features for subsequent recognition.

  10. a Time-Resolved Photographic Study of Lightning in the Thunderstorm Research International Program

    Science.gov (United States)

    Idone, Vincent Peter

    Time-resolved recordings of 118 strokes in both natural and artificially triggered lightning flashes obtained during participation in the Thunderstorm Research International Program (TRIP) have allowed the measurement of leader and return stroke propagation speeds, providing the largest single body of such data to date. The mean two-dimensional return stroke propagation speed found for 63 natural lightning strokes is 11 x 10('7) m/s. The distribution of measured propagation speeds peaks strongly at (TURN)9 x 10('7) m/s and extends from 2.9 to 24 x 10('7) m/s. Propagation speed reductions in upper channel segments are observed in both first and subsequent strokes. Those results are compared with the earlier work of Schonland and McEachron; substantial disparities are found and examined. The return stroke propagation speeds of the triggered lightning strokes are evaluated in three dimensions via stereo photography of the lightning. A mean of 11 x 10('7) m/s is found for 55 strokes, with a range of 6.4 to 16 x 10('7) m/s. Return stroke propagation speed reductions during propagation along the channel are also observed for these triggered lightning strokes. Propagation speeds are determined for 21 natural and 32 triggered lightning dart leaders, with means of 11 x 10('6) m/s and 18 x 10('6) m/s, respectively. Dart leader propagation speed increases near ground are reported for the first time. Variations in the propagation speed and luminous characteristics of four natural lightning dart-stepped leaders, two triggered lightning dart-stepped leaders, and three natural lightning stepped leaders are examined. The analysis reveals a positive correlation between the dart length and the dart leader propagation speed, this being observed in both natural and triggered lightning. Also, a correlation is found between the dart leader and return stroke propagation speed for the triggered lightning data; no such correlation is found for natural lightning. For one stroke of the

  11. Two consecutive thunderstorm associated epidemics of asthma in the city of Melbourne. The possible role of rye grass pollen.

    Science.gov (United States)

    Bellomo, R; Gigliotti, P; Treloar, A; Holmes, P; Suphioglu, C; Singh, M B; Knox, B

    1992-06-15

    To document the clinical impact and identify the meteorological and environmental circumstances surrounding two epidemics of asthma exacerbations associated with thunderstorms in the city of Melbourne and to find a possible aetiology for these events. Collection of meteorological and environmental data from the Victorian Bureau of Meteorology and the Environment Protection Authority; collection of clinical data from metropolitan emergency departments and the Victorian Ambulance Service; and study of a cohort of affected patients with asthma and a control group of asthmatics who were not affected by the storms. Tertiary institution. Twelve storm-affected patients with asthma and 16 asthmatics not affected by the storms. Administration of a questionnaire, medical interview, pulmonary function tests and skin prick tests with common allergens. Both epidemics caused a major increase in the number of hospital attendances and admissions because of asthma exacerbation (five to ten fold rise). These events could not be related to atmospheric pollution or specific meteorological features of the storms. Patients affected by the second storm were significantly more likely to suffer from hay fever (P less than 0.05), rye grass pollen allergy (P less than 0.05) and allergy to rainfall released rye grass starch granules (P less than 0.025). Late spring thunderstorms in the city of Melbourne can trigger epidemics of asthma attacks. The seasonal nature of the phenomenon and the pattern of allergic responses found in affected patients suggest a possible aetiological role for rye grass pollen.

  12. New model simulations of the global atmospheric electric circuit driven by thunderstorms and electrified shower clouds: The roles of lightning and sprites

    DEFF Research Database (Denmark)

    Rycroft, Michael J.; Odzimek, Anna; Arnold, Neil F.

    2007-01-01

    Several processes acting below, in and above thunderstorms and in electrified shower clouds drive upward currents which close through the global atmospheric electric circuit, These are all simulated in a novel way using the software package PSpice. A moderate negative cloud-to-ground lightning di...

  13. The ensemble forecasting technique of the thunderstorm and its application%雷暴云的集合预报技术及其应用

    Institute of Scientific and Technical Information of China (English)

    王佳; 智协飞; 陈钰文; 商兆堂; 白卡娃

    2012-01-01

    A thunderstorm ensemble forecasting approach is perti~rmed by the ensemble analysis of the cloud model' s forecast results according to the initial condition aggregation provided by the grid fore-cast results of the mesoscale non-hydrostatic WRF model. The approach is applied to forecast the char-acteristics of thunderstorm around Nanjing one day in advance and is verified by the Doppler radar data of the thunderstorms in summer in Nanjing. Results show that the intensity and distribution of thunder-storms over the research area is reasonably predicted one day in advance. It is particularly good to fore-cast the distribution of the strong thunderstorms by using the ensemble forecasting technique. Moreover, the application of the PDF(probability density function)of thunderstorms' duration into the probability forecasting of the influenced area of thunderstorms improves the radar' s warning and monitoring capac-ity of local thunderstorms.%以中尺度非静力WRF模式的格点预报结果作为云模式的初值集合,经云模式的多初值雷暴预报及预报结果的集合分析,建立了雷暴云的集合预报方法。将该方法应用于南京周边地区未来一天雷暴天气的特征预报,并利用南京夏季9个雷暴天气的多普勒雷达资料(SCIT,storm cell identification and tracking)进行预报效果的检验。结果表明,雷暴云的集合预报对研究区域内未来一天雷暴强度、分布预报效果较好,尤其对强雷暴的分布有较强的预警预测能力。此外,雷暴持续时间概率密度分布的集合预报产品,在雷暴影响范围概率预报上的应用,提高了雷达对雷暴的预警监测能力。

  14. Lightning return stroke velocities in the thunderstorm research international program (TRIP)

    Science.gov (United States)

    Idone, Vincent P.; Orville, Richard E.

    1982-06-01

    We have used high-speed streaking photographic techniques to time-resolve the luminous components of cloud-to-ground lightning flashes. Two-dimensional return stroke velocities have been measured for 63 strokes representing, we believe, the largest set of return stroke velocity measurements obtained to date. All recordings were made during our participation in the Thunderstorm Reseach International Program conducted at the Kennedy Space Center, Florida, during the summers of 1977 and 1978 and at the Langmuir Laboratory near Socorro, New Mexico, during the summer of 1979. The mean return stroke velocity, near ground (channel length ≤1.3 km), was found to be 11×107 m/s, with a maximum relative error estimate in most cases of 35% or less. The distribution of velocities peaks strongly at approximately 9×107 m/s. Thirty-two of the 63 values (51%) fall within the interval of 8-12 × 107 m/s. The range of observed velocities spans the interval of 2.9-24×107 m/s. Based on the presence of branches in the time-resolved recordings, 17 strokes are considered to be first return strokes, with a mean velocity, near ground, of 9.6×107 m/s. The mean velocity for subsequent strokes is 12×107 m/s. A further breakdown of the results for Florida and New Mexico, respectively, reveals mean first return stroke velocities of 6.6×107 m/s and 15 × 107 m/s as well as mean subsequent stroke velocities of 11×107 m/s and 13 × 107 m/s. Velocity variations for 17 of the best events are presented, with the return stroke velocity observed to decrease with height in every case except one. The velocity reduction can be substantial; velocities in upper channel lengths were often reduced by 25% or more relative to velocities near ground, even for subsequent strokes. The variation of velocity between strokes in multistroke flashes was found to be significant in some cases and minor in others. The results of this study are compared with the earlier major works of Schonland and of Mc

  15. Producing Presences

    OpenAIRE

    Mandagará, Pedro

    2008-01-01

    Resenha de MENDES, Victor K.; ROCHA, João Cezar de Castro (Eds.). Producing Presences: branching out from Gumbrecht’s work. Dartmouth, Massachusetts: University of Massachusetts Dartmouth, 2007. (Adamastor book series, 2)

  16. Electric Currents and Fields in Middle and Low Atmosphere in Fair-Weather Regions due to Distant Thunderstorms

    Science.gov (United States)

    Velinov, Peter; Velinov, Peter; Tonev, Peter

    The electric currents created by the thunderstorms and the electrified shower clouds over the Earth flow into the global atmospheric electric circuit and are responsible for the formation in fair-weather regions of ionosphere-ground current of about 2 pA per square meter, as well as for the related fair-weather electric field of the order of 100 V/m at sea level. The link of the diurnal variations of the fair-weather electric field with the global thunderstorm activity has been widely studied with connection to the Wilson's hypothesis. To confirm this hypothesis directly, also the fair-weather electric field response to a strong single lightning discharge has being examined. Here we study theoretically the variations of the electric currents and fields in fair-weather regions at different altitudes of the lower and middle atmosphere, which are provoked by distant lightning discharges. The electric field variations can play an important role at higher altitudes (in the upper troposphere and above), where they are much larger and possibly influence the physical and chemical processes. For our goals we realize a globalscale model of the electric fields and currents generated by a lightning discharge, which is based on the Maxwell's equations. The fair-weather electric characteristics are studied by our model depending on the lightning parameters, location and distance. We also examine how variations of the conductivity in the strato/mesosphere due to changes of solar and geomagnetic activity affect the characteristics studied. Another question discussed is whether and how the mesospheric electric response to a remote lightning discharge is influenced by the conductivity anisotropy above 70 km and by the geomagnetic field geometry. The variations of the fairweather electric fields due to a distant lightning at tropospheric heights are also studied with respect to their presumable role in the cloud physics.

  17. Lightning and Rainfall Characteristics in Elevated vs. Surface Based Convection in the Midwest that Produce Heavy Rainfall

    Directory of Open Access Journals (Sweden)

    Joshua S. Kastman

    2017-02-01

    Full Text Available There are differences in the character of surface-based and elevated convection, and one type may pose a greater threat to life or property. The lightning and rainfall characteristics of eight elevated and eight surface-based thunderstorm cases that occurred between 2007 and 2010 over the central Continental United States were tested for statistical differences. Only events that produced heavy rain (>50.8 mm·day−1 were investigated. The nonparametric Mann–Whitney test was used to determine if the characteristics of elevated thunderstorm events were significantly different than the surface based events. Observations taken from these cases include: rainfall–lightning ratios (RLR within the heavy rain area, the extent of the heavy rainfall area, cloud-to-ground (CG lightning flashes, CG flashes·h−1, positive CG flashes, positive CG flashes·h−1, percentage of positive CG flashes within the heavy rainfall area, and maximum and mean rainfall amounts within the heavy rain area. Results show that elevated convection cases produced more rainfall, total CG lightning flashes, and positive CG lightning flashes than surface based thunderstorms. More available moisture and storm morphology explain these differences, suggesting elevated convection is a greater lightning and heavy rainfall threat than surface based convection.

  18. 西天山地区雷暴和闪电特征分析%Characteristics of Thunderstorm and Lightning in Western Tianshan Areas

    Institute of Scientific and Technical Information of China (English)

    阿吉古丽·沙依提; 尹仔锋; 卡哈尔·亚森; 塔伊尔·艾则孜; 哈依霞·哈力; 古丽尼沙·麦提库尔班

    2013-01-01

    The Characteristics of Thunderstorm and Lightning in Western Tianshan Areas were analyzed by use of thunderstorm data from 1960 to 2010 and lightning monitor data in 2008. The results showed as follows: The pattern of spatial distribution of thunderstorms in Western Tianshan areas was characterized by rare in the south and north but more in the east and west. The annual mean days of thunderstorm in Western Tianshan area was 17.3 to 85.5 days, and the thunderstorm days decreased at the rate of 2.7 days per decade in the recent 51 years. The monthly variation of thunderstorm average days shows single peak, and reached its peak in June and July. It is found that positive lightning is mainly lightning in Western Tianshan area and its ratio is 66% .The intensity of lightning is mainly concentrated in -130~ +63KA and intensity of negative lightning is greater than intensity of positive lightning.%利用西天山地区14个气象站1960-2010年雷暴资料和新疆雷电监测网2008年观测资料,分析了西天山地区雷暴和闪电变化特征。结果表明:西天山地区年平均雷暴日数分布呈东西多,南北少的形势。该区域年平均雷暴日数在17.3~85.5 d之间,并以2.7 d/10 a的速率减少。西天山地区雷暴日数的年变化呈单峰型,并在6-7月达到最大值。整个区域以正闪为主,正闪占总闪的比例达66%。该区域闪电电流强度在-130~+63 kA之间,负闪强度大于正闪强度。

  19. A Case Study on Supercell Storm of Hail in the Northwest of Guangxi%桂西北一次超级单体风暴过程的分析

    Institute of Scientific and Technical Information of China (English)

    农孟松; 祁丽燕; 黄海洪; 邓汝伊; 班荣贵

    2011-01-01

    本文利用常规观测资料和多普勒天气雷达资料,对2009年4月12日发生在广西西北部的大范围冰雹天气进行分析,得出以下结论:(1)导致冰雹发生的天气系统是高空低涡和低层切变线,冰雹发生前上午百色探空站有中等对流有效位能、上干下湿层结结构、强的深层垂直环境风切变,速度矢图上低层强的顺时针旋转曲率,已经具备强对流潜势发生条件。(2)超级单体右前方的低层反射率因子呈现明显的钩状回波,是超级单体风暴的典型特征之一。反射率因子垂直剖面呈现出典型的有界弱回波区、回波悬垂和回波墙。最大的回波强度出现在沿着回波墙的一个竖直的狭长区域,其值超过65 dBz。相应的中低层径向速度图呈现一个中等强度的中气旋,旋转速度达到22 m·s-;垂直累积液态水含量和密度分别超过70kg·m~(-2)和5 g·m~(-3)。(3)高空低涡正涡度区、高CAPE值、地面辐合线在右江河谷滞留以及特殊地形作用,是多个对流单体沿相似路径移动的主要原因。%Based on the routine observation data and the Doppler weather radar data,the large-scale hail in the northwest of Guangxi is analyzed.The results show that;(1) The systems csusing hail are upper-air-vortex and low-level shear line.Although the CAPE was moderate before the hail,it has necessary conditions for the severe convection potential occurrence such as the stratification of upper dry and lower wet, strong environmental wind shear and the strong clockwise curvature at low levels.(2) The low-level reflectivity on the right front of the supercell shows a typical hook echo and it is a typical feature of super-cells. Along the inflow direction and through the strongest echo,the reflectivity shows typical BWER (Boundary Weak Echo Region),overhang echo and echo wall.The strongest echo is within a vertical narrow region along the echo wall and can be more

  20. 一次超级单体风暴引发的局地大暴雨成因分析%Analysis on the Cause of a Local Heavy Precipitation Caused by a Supercell Storm

    Institute of Scientific and Technical Information of China (English)

    崔新建; 魏慧娟; 贾文秀; 翟怀巍

    2011-01-01

    从大暴雨发生前后气象要素变化、环流背景、影响系统、区域流场入手,对2009年8月28日发生在驻马店市的突发性局地大暴雨天气过程进行了分析.结果表明,这次突发性大暴雨过程具有明显的中小尺度系统特征,主要影响系统是850、700 hPa切变线和地面辐合线.通过对多普勒天气雷达基本反射率因子、径向速度和风廓线产品的分析,发现"V"型缺口、钩状回波、中气旋的特征明显,充分说明了这次局地大暴雨过程是超级单体风暴造成的.%The sudden local severe precipitation in Zhumadian City on August 28, 2009 was analyzed from the aspects of meteorological elements change, the atmospheric circulation background, the influence system and the region flow field before and after the severe precipitation. The results showed that this heavy storm had obvious meso-small scale system characteristics, the major affect system were the shear lines in 850 and 700 hPa and the ground convergence line. Through the analysis of the Doppler weather radar basic index such as the reflection factor, the radial velocity and the wind profile, it was find that the characteristics of “V” notched, the hook echo and the eyelone were obvious, those showed that this local heavy precipitation was caused by the supercell storm.

  1. Effect of near-earth thunderstorms electric field on the intensity of ground cosmic ray positrons/electrons in Tibet

    Science.gov (United States)

    Zhou, X. X.; Wang, X. J.; Huang, D. H.; Jia, H. Y.

    2016-11-01

    Monte Carlo simulations are performed to study the correlation between the ground cosmic ray intensity and near-earth thunderstorms electric field at YBJ (located at YangBaJing, Tibet, China, 4300 m a. s. l.). The variations of the secondary cosmic ray intensity are found to be highly dependent on the strength and polarity of the electric field. In negative fields and in positive fields greater than 600 V/cm, the total number of ground comic ray positrons and electrons increases with increasing electric field strength. And these values increase more obviously when involving a shower with lower primary energy or a higher zenith angle. While in positive fields ranging from 0 to 600 V/cm, the total number of ground comic ray positrons and electrons declines and the amplitude is up to 3.1% for vertical showers. A decrease of intensity occurs in inclined showers within the range of 0-500 V/cm, which is accompanied by smaller amplitudes. In this paper, the intensity changes are analyzed, especially concerning those decreasing phenomena in positive electric fields. Our simulation results could be helpful in understanding the decreases observed in some ground-based experiments (such as the Carpet air shower array and ARGO-YBJ), and also be useful in understanding the acceleration mechanisms of secondary charged particles caused by an atmospheric electric field.

  2. Effect of near-earth thunderstorms electric field on the intensity of ground cosmic ray positrons/electrons in Tibet

    CERN Document Server

    Zhou, X X; Huang, D H; Jia, H Y

    2016-01-01

    Monte Carlo simulations are performed to study the correlation between the ground cosmic ray intensity and near-earth thunderstorms electric field at YBJ (4300 m a.s.l., Tibet, China). The variations of the secondary cosmic ray intensity are found to be highly dependent on the strength and polarity of the electric field. In negative fields and in positive fields greater than 600 V/cm, the total number of ground comic ray positrons and electrons increases with increasing electric field strength. And these values increase more obviously when involving a shower with lower primary energy or a higher zenith angle. While in positive fields ranging from 0 to 600 V/cm, the total number of ground comic ray positrons and electrons declines and the amplitude is up to 3.1% for vertical showers. A decrease of intensity occurs for inclined showers in positive fields less than 500 V/cm, which is accompanied by smaller amplitudes. In this paper, the intensity changes are discussed, especially concerning the decreases in posi...

  3. Radar Rainfall Estimates for Modeling Flood Response to Orographic Thunderstorms in the Central Appalachians

    Science.gov (United States)

    Hicks, N. S.; Smith, J. A.

    2001-12-01

    We examine the hydrometeorology and hydrology of extreme flooding from orographic convective systems in the central Appalachian region. Analyses of flood response are based on rainfall and discharge observations for major flood events along the western margin of the central Appalachians (16-17 May 1996, 18-19 July 1996, 30-31 July 1996, 28-29 June 1998, and 7-8 July 2001). A distributed hydrologic model is used to access flood response in Appalachian basins with diverse physiographic properties. High-resolution (1 km, 5 minutes) rainfall fields derived from WSR-88D radars in Charleston, West Virginia and Pittsburgh, Pennsylvania are used for model analyses. Cloud-to-ground lightning and the IFLOWs raingage network provide additional information for hydrometeorological analyses. Flood response is viewed in the context of land surface hydrologic processes and frequency of extreme precipitation events. Orographic convective systems in the Appalachians have produced some of the largest rainfall accumulations in the world for time intervals less than 6 hours and some of the largest unit discharge flood peaks for the U.S. east of the Mississippi River. The 18 July 1942 Smethport, Pennsylvania storm, for example, produced the world record rainfall accumulation of 780 mm in 4.5 hours.

  4. Recent Advances in the Tempest UAS for In-Situ Measurements in Highly-Dynamic Environments

    Science.gov (United States)

    Argrow, B. M.; Frew, E.; Houston, A. L.; Weiss, C.

    2014-12-01

    The spring 2010 deployment of the Tempest UAS during the VORTEX2 field campaign verified that a small UAS, supported by a customized mobile communications, command, and control (C3) architecture, could simultaneously satisfy Federal Aviation Administration (FAA) airspace requirements, and make in-situ thermodynamic measurements in supercell thunderstorms. A multi-hole airdata probe was recently integrated into the Tempest UAS airframe and verification flights were made in spring 2013 to collect in-situ wind measurements behind gust fronts produced by supercell thunderstorms in northeast Colorado. Using instantaneous aircraft attitude estimates from the autopilot, the in-situ measurements were converted to inertial wind estimates, and estimates of uncertainty in the wind measurements was examined. To date, the limited deployments of the Tempest UAS have primarily focused on addressing the engineering and regulatory requirements to conduct supercell research, and the Tempest UAS team of engineers and meteorologists is preparing for deployments with the focus on collecting targeted data for meteorological exploration and hypothesis testing. We describe the recent expansion of the operations area and altitude ceiling of the Tempest UAS, engineering issues for accurate inertial wind estimates, new concepts of operation that include the simultaneous deployment of multiple aircraft with mobile ground stations, and a brief description of our current effort to develop a capability for the Tempest UAS to perform autonomous path planning to maximize energy harvesting from the local wind field for increased endurance.

  5. Numerical simulation of narrow bipolar electromagnetic pulses generated by thunderstorm discharges

    Science.gov (United States)

    Bochkov, E. I.; Babich, L. P.; Kutsyk, I. M.

    2013-07-01

    Using the concept of avalanche relativistic runaway electrons (REs), we perform numerical simulations of compact intracloud discharge (CID) as a generator of powerful natural electromagnetic pulses (EMPs) in the HF-VHF range, called narrow bipolar pulses (NBPs). For several values of the field overvoltage and altitude at which the discharge develops, the numbers of seed electrons initiating the avalanche are evaluated, with which the calculated EMP characteristics are consistent with the measured NBP parameters. We note shortcomings in the hypothesis assuming participation of cosmic ray air showers in avalanche initiation. The discharge capable of generating NBPs produces REs in numbers close to those in the source of terrestrial γ-ray flashes (TGFs), which can be an argument in favor of a unified NBP and TGF source.

  6. Numerical simulation of narrow bipolar electromagnetic pulses generated by thunderstorm discharges

    Energy Technology Data Exchange (ETDEWEB)

    Bochkov, E. I.; Babich, L. P., E-mail: babich@elph.vniief.ru; Kutsyk, I. M. [All-Russia Research Institute of Experimental Physics, Russian Federal Nuclear Center (Russian Federation)

    2013-07-15

    Using the concept of avalanche relativistic runaway electrons (REs), we perform numerical simulations of compact intracloud discharge (CID) as a generator of powerful natural electromagnetic pulses (EMPs) in the HF-VHF range, called narrow bipolar pulses (NBPs). For several values of the field overvoltage and altitude at which the discharge develops, the numbers of seed electrons initiating the avalanche are evaluated, with which the calculated EMP characteristics are consistent with the measured NBP parameters. We note shortcomings in the hypothesis assuming participation of cosmic ray air showers in avalanche initiation. The discharge capable of generating NBPs produces REs in numbers close to those in the source of terrestrial {gamma}-ray flashes (TGFs), which can be an argument in favor of a unified NBP and TGF source.

  7. Thunderstorms as probable reason of high background neutron fluxes on L<1.2

    Science.gov (United States)

    Bratolyubova-Tsulukidze, L.; Grachev, E.; Grigoryan, O.; Kunitsyn, V.; Kuzhevskiy, B.; Nechaev, O.; Usanova, M.

    In this paper we analyze the neutron emission observations made in the experiment onboard MIR orbital station (1991), ISS (2002) and Colibri-2002 satellite (2002) at the altitude of 400 km. The helium discharge detectors made it possible to detect neutrons with energies ranging from 0.25eV to 1.9MeV. The spatial distribution of high background neutron fluxes has a longitude dependence. These events have been observed at -200 ... 600 and 1350 ...1800 ...- 1350 longitudinal intervals. The most intensive fluxes near the geomagnetic equator were registered in the African region. They are not found to be associated with increases of proton fluxes (Ep >50MeV). As a statistical set, the events appear to coincide with the most active region of atmospheric weather. In this paper we assess the possibility that the occurrence of high background neutron fluxes in the African region is connected with lightning discharges. To observe neutron emission at the altitude of 400 km ~101 0 neutrons are required to be produced by lightning discharge. These theoretical predictions suggest cloud charge values of about 250-300 Coulomb.

  8. THUNDERSTORM ACTIVITY AND LIGHTNING PROTECTION OF POWER PLANTS AND EQUIPMET ON THE TERRITORY OF AZERBAIJAN REPUBLIC

    Directory of Open Access Journals (Sweden)

    A. M. Gashimov

    2015-01-01

    Full Text Available In the article the results of a wind parameters analysis at the wind power parks construction territory in the north of the Azerbaijan Republic are presented. By means of extrapolation the  speeds  of  a  wind  stream  at  heights  of  80  and  100  m  have  been  calculated.  In  the conditions  of the  Azerbaijan  Republic  initially the  wind  potential  was  defined  at  height of 10–15 m from the earth surface by the data of the “weather vane” established at hydrome- teorological station, located within the precincts of Baku city. The subsequent measurements were spent at height of 40 m by means of “anemometer” located outside of city boundaries in a southern direction. It is established that at height of 100 m the wind speed essentially ex- ceeds the wind speed at height of 22 m. Hence, the height of 100 m is profitable for construc- tion and operation of wind constructions. Results of actual measurements have shown that wind speed depends on height and time of day. It is established that change of a wind stream within a month corresponds to change of the daily schedule of power station capacity and correlation factor of two processes appears high enough and makes 0.61. Note that for building the park of wind power plant it is necessary within 1 year continuously to spend actual meas- urements of a wind parameters at various heights (to 100 m. Otherwise placing of wind sta- tion on the given site can be not profitable. It is necessary to notice that the efficiency of wind units, besides their constructive features also depends on a correct choice of their installation place.On the other hand, the transmission of energy, produced by the wind power plants, in the power supply systems to the consumer is closely connected with a wind speed, air density, distribution of a wind stream, etc. parameters. From the told follows that research of a wind parameters represents the economic and somewhat legal value.

  9. Analysis of a rare hail-producing tornado event on 20 March 2013in Dongguan, Guangdong Province%2013年3月20日广东东莞罕见龙卷冰雹特征及成因分析

    Institute of Scientific and Technical Information of China (English)

    张劲梅; 莫伟强

    2013-01-01

    Based on conventional surface and upper-air data, reanalysis data from NCEP/NCAR, and nonconventional data from Doppler weather radar and surface automatic weather station (AWS), we analyzed a disastrous severe convective weather event with rare tornado and hail on 20 March 2013 in Dongguan, Guangdong Province. The results are summarized as follows. 1) The pressure, temperature, wind direc-tion, and wind speed observed at the station passed over by the tornado clearly have different characteristics from those caused by thunder-storm gales. 2) The following factors provided a favorable atmospheric condition for the development of convections:the increasing strong wind with altitude in Southern China, the unstable potential stratification with the dry air above and humid air below, and the high humidity and temperature in the low-levels. Additionally, cold air moving southwards, and meso-and micro-scale convergence systems near the ground served as a trigger mechanism for the tornado event. 3) The genesis of the tornado is possibly resulted from the moderate convective available potential energy (CAPE), deep and strong vertical wind shear between 0 and 6 km, and 0-1 km low level wind shear. 4) The strengthening of convective storms associated with the hail-producing tornado is closely related to the intensifying of the meso-and micro-scale convergence systems near the ground. 5) The strongest radar echo is 72 dBz, observed when hail, gale and tornado occurred simultaneously. The tornado occurred near the hook-shaped echo embedded in a supercell close to the rear V-shaped gap. Three body scattering (TBSS) echoes were ob-served multiple times, which corresponds to hails. The low-level weak echo region, and mid-and high-level echo pendency can be found in radar reflectivity vertical profiles, and the bounded weak echo region (BWER) emerges 20 minutes earlier than tornado. When tornado emerg-es, tornado vortex (TVS) and mesocyclone in the supercell storm can be found in

  10. On the Nature of Severe Orographic Thunderstorms near the Andes in Subtropical South America

    Science.gov (United States)

    Rasmussen, Kristen Lani Emi

    Identifying common features and differences between the mechanisms producing extreme convection near major mountain ranges of the world is an essential step toward a general understanding of orographic precipitation on a global scale. The overarching objective of this dissertation is to understand and examine orographic convective processes in general, while specifically focusing on systems in the lee of the Andes Mountains. Diagnosing the key ingredients necessary for generating high impact weather near extreme topography is crucial to our understanding of orographic precipitating systems. An investigation of the most intense storms in 11 years of TRMM Precipitation Radar (PR) data has shown a tendency for squall lines to initiate and develop east of the Andes with a mesoscale organization similar to storms in the U.S. Great Plains (Rasmussen and Houze 2011). In subtropical South America, however, the topographical influence on the convective initiation and maintenance of the mesoscale convective systems (MCSs) is unique. The Andes and other mountainous terrain of Argentina focus deep convective initiation in the foothills of western Argentina (Romatschke and Houze 2010; Rasmussen and Houze 2011). Subsequent to initiation, the convection often evolves into propagating MCSs similar to those seen over the U.S. Great Plains sometimes producing damaging tornadoes, hail and floods across a wide agricultural region (Rasmussen and Houze 2011; Rasmussen et al. 2014b). The TRMM satellite was designed to determine the spatial and temporal variation of tropical and subtropical rainfall amounts and storm structures around the globe with the goal of understanding the factors controlling the precipitation. However, the TRMM PR algorithm significantly underestimates surface rainfall in deep convection over land (Nesbitt et al. 2004; Iguchi et al. 2009; Kozu et al. 2009). When the algorithm rates are compared to a range of conventional Z-R relations, the rain bias tends to be

  11. Utilizing TRMM to Analyze Sea Breeze Thunderstorm Patterns During El Nino Southern Oscillations and Their Effects upon Available Fresh Water for South Florida Agricultural Planning and Management

    Science.gov (United States)

    Cooley, Clayton; Billiot, Amanda; Lee, Lucas; McKee, Jake

    2010-01-01

    Water is in high demand for farmers regardless of where you go. Unfortunately, farmers in southern Florida have fewer options for water supplies than public users and are often limited to using available supplies from surface and ground water sources which depend in part upon variable weather patterns. There is an interest by the agricultural community about the effect weather has on usable surface water, however, research into viable weather patterns during La Nina and El Nino has yet to be researched. Using rainfall accumulation data from NASA Tropical Rainfall Measurement Mission (TRMM) satellite, this project s purpose was to assess the influence of El Nino and La Nina Oscillations on sea breeze thunderstorm patterns, as well as general rainfall patterns during the summer season in South Florida. Through this research we were able to illustrate the spatial and temporal variations in rainfall accumulation for each oscillation in relation to major agricultural areas. The study period for this project is from 1998, when TRMM was first launched, to 2009. Since sea breezes in Florida typically occur in the months of May through October, these months were chosen to be the months of the study. During this time, there were five periods of El Nino and two periods of La Nina, with a neutral period separating each oscillation. In order to eliminate rainfall from systems other than sea breeze thunderstorms, only days that were conducive to the development of a sea breeze front were selected.

  12. 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.

  13. Whistler intensities above thunderstorms

    Directory of Open Access Journals (Sweden)

    J. Fiser

    2010-01-01

    Full Text Available We report a study of penetration of the VLF electromagnetic waves induced by lightning to the ionosphere. We compare the fractional hop whistlers recorded by the ICE experiment onboard the DEMETER satellite with lightning detected by the EUCLID detection network. To identify the fractional hop whistlers, we have developed software for automatic detection of the fractional-hop whistlers in the VLF spectrograms. This software provides the detection times of the fractional hop whistlers and the average amplitudes of these whistlers. Matching the lightning and whistler data, we find the pairs of causative lightning and corresponding whistler. Processing data from ~200 DEMETER passes over the European region we obtain a map of mean amplitudes of whistler electric field as a function of latitudinal and longitudinal difference between the location of the causative lightning and satellite magnetic footprint. We find that mean whistler amplitude monotonically decreases with horizontal distance up to ~1000 km from the lightning source. At larger distances, the mean whistler amplitude usually merges into the background noise and the whistlers become undetectable. The maximum of whistler intensities is shifted from the satellite magnetic footprint ~1° owing to the oblique propagation. The average amplitude of whistlers increases with the lightning current. At nighttime (late evening, the average amplitude of whistlers is about three times higher than during the daytime (late morning for the same lightning current.

  14. 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.; Bradshaw, T.; Gatlin, P.

    2005-07-01

    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 -1 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 -1) 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 -1, 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.

  15. NASA thunderstorm overflight program: Atmospheric electricity research. An overview report on the optical lightning detection experiment for spring and summer 1983

    Science.gov (United States)

    Vaughan, O. H., Jr.

    1984-01-01

    This report presents an overview of the NASA Thunderstorm Overflight Program (TOP)/Optical Lightning Experiment (OLDE) being conducted by the Marshall Space Flight Center and university researchers in atmospheric electricity. Discussed in this report are the various instruments flown on the NASA U-2 aircraft, as well as the ground instrumentation used in 1983 to collect optical and electronic signatures from the lightning events. Samples of some of the photographic and electronic signatures are presented. Approximately 4132 electronic data samples of optical pulses were collected and are being analyzed by the NASA and university researchers. A number of research reports are being prepared for future publication. These reports will provide more detailed data analysis and results from the 1983 spring and summer program.

  16. 强风暴个例电荷结构及云闪放电差异的数值模拟%Numerical Simulation of Difference of Electric Structure and Discharge of Cloud Flash for Two Severe Thunderstorm Cases

    Institute of Scientific and Technical Information of China (English)

    周志敏; 郭学良; 崔春光; 李兴宇; 付丹红; 赵玉春

    2012-01-01

    The electric structure and discharge of cloud flash between two severe thunderstorm cases (one is with hail shooting process and the other is without hail shooting process, expressed by H case and NH case, respectively) in Changchun city, Jilin Provence was simulated and comparatively analyzed by a three-dimensional hail-category cloud model coupled with electrification process. Results show that the e- lectric structures of the two cases caused by the weak updraft at the initial stage of severe thunderstorm are similar and both have a weak positive-pole distribution. With the development of thunderstorm, the differ ence of the electric structure occurs. Stronger updraft and wind shear in H case make super-cooled water and ice phase particle be carried to higher level in different regions in where the ice phase particle grow, which produces several content center of ice phase particle so that the non-inductive processes at different regions with different environment parameters and sign of charge in ice phase particles occur and several charge centers develop. And the charge is apt to show a multi-layered distribution. The different distribu- tions of charge at different stages could be initiated at both updraft zones and divergence zone. With rela- tively weaker updraft and wind shear, the distribution of the ice phase particle in NH case is more regular, so is the non-inductive process. And the distribution of charge is well-distributed and more regular at dif- ferent stages. Therefore, the position where lightning flashe might is similar to some extent.%利用耦合电过程的冰粒子分档模式对长春地区两个降雹型和非降雹型强风暴个例的闪电特征进行了模拟和对比分析。结果表明,在雷暴云的初始发展期,由于上升气流较弱,两者电荷分布相似,均表现为弱的正偶极结构。随着云体不断发展,两者电荷分布开始表现出差异:降雹型个例中的上升气流较强,风切变

  17. Observations of Two Sprite-Producing Storms in Colorado

    Science.gov (United States)

    Lang, Timothy J.; Lyons, Walter A.; Cummer, Steven A.; Fuchs, Brody R.; Dolan, Brenda; Rutledge, Steven A.; Krehbiel, Paul; Rison, William; Stanley, Mark; Ashcraft, Thomas

    2016-01-01

    Two sprite-producing thunderstorms were observed on 8 and 25 June 2012 in northeastern Colorado by a combination of low-light cameras, a lightning mapping array, polarimetric and Doppler radars, the National Lightning Detection Network, and charge moment change measurements. The 8 June event evolved from a tornadic hailstorm to a larger multicellular system that produced 21 observed positive sprites in 2 h. The majority of sprites occurred during a lull in convective strength, as measured by total flash rate, flash energy, and radar echo volume. Mean flash area spiked multiple times during this period; however, total flash rates still exceeded 60 min(sup 1), and portions of the storm featured a complex anomalous charge structure, with midlevel positive charge near 20degC. The storm produced predominantly positive cloud-to-ground lightning. All sprite-parent flashes occurred on the northeastern flank of the storm, where strong westerly upper level flow was consistent with advection of charged precipitation away from convection, providing a pathway for stratiform lightning. The 25 June event was another multicellular hailstorm with an anomalous charge structure that produced 26 positive sprites in less than 1 h. The sprites again occurred during a convective lull, with relatively weaker reflectivity and lower total flash rate but relatively larger mean flash area. However, all sprite parents occurred in or near convection and tapped charge layers in adjacent anvil cloud. The results demonstrate the sprite production by convective ground strokes in anomalously charged storms and also indicate that sprite production and convective vigor are inversely related in mature storms.

  18. Observations of two sprite-producing storms in Colorado

    Science.gov (United States)

    Lang, Timothy J.; Lyons, Walter A.; Cummer, Steven A.; Fuchs, Brody R.; Dolan, Brenda; Rutledge, Steven A.; Krehbiel, Paul; Rison, William; Stanley, Mark; Ashcraft, Thomas

    2016-08-01

    Two sprite-producing thunderstorms were observed on 8 and 25 June 2012 in northeastern Colorado by a combination of low-light cameras, a lightning mapping array, polarimetric and Doppler radars, the National Lightning Detection Network, and charge moment change measurements. The 8 June event evolved from a tornadic hailstorm to a larger multicellular system that produced 21 observed positive sprites in 2 h. The majority of sprites occurred during a lull in convective strength, as measured by total flash rate, flash energy, and radar echo volume. Mean flash area spiked multiple times during this period; however, total flash rates still exceeded 60 min-1, and portions of the storm featured a complex anomalous charge structure, with midlevel positive charge near -20°C. The storm produced predominantly positive cloud-to-ground lightning. All sprite-parent flashes occurred on the northeastern flank of the storm, where strong westerly upper level flow was consistent with advection of charged precipitation away from convection, providing a pathway for stratiform lightning. The 25 June event was another multicellular hailstorm with an anomalous charge structure that produced 26 positive sprites in less than 1 h. The sprites again occurred during a convective lull, with relatively weaker reflectivity and lower total flash rate but relatively larger mean flash area. However, all sprite parents occurred in or near convection and tapped charge layers in adjacent anvil cloud. The results demonstrate the sprite production by convective ground strokes in anomalously charged storms and also indicate that sprite production and convective vigor are inversely related in mature storms.

  19. Spatial-temporal clustering of tornadoes

    Science.gov (United States)

    Malamud, Bruce D.; Turcotte, Donald L.; Brooks, Harold E.

    2016-12-01

    The standard measure of the intensity of a tornado is the Enhanced Fujita scale, which is based qualitatively on the damage caused by a tornado. An alternative measure of tornado intensity is the tornado path length, L. Here we examine the spatial-temporal clustering of severe tornadoes, which we define as having path lengths L ≥ 10 km. Of particular concern are tornado outbreaks, when a large number of severe tornadoes occur in a day in a restricted region. We apply a spatial-temporal clustering analysis developed for earthquakes. We take all pairs of severe tornadoes in observed and modelled outbreaks, and for each pair plot the spatial lag (distance between touchdown points) against the temporal lag (time between touchdown points). We apply our spatial-temporal lag methodology to the intense tornado outbreaks in the central United States on 26 and 27 April 2011, which resulted in over 300 fatalities and produced 109 severe (L ≥ 10 km) tornadoes. The patterns of spatial-temporal lag correlations that we obtain for the 2 days are strikingly different. On 26 April 2011, there were 45 severe tornadoes and our clustering analysis is dominated by a complex sequence of linear features. We associate the linear patterns with the tornadoes generated in either a single cell thunderstorm or a closely spaced cluster of single cell thunderstorms moving at a near-constant velocity. Our study of a derecho tornado outbreak of six severe tornadoes on 4 April 2011 along with modelled outbreak scenarios confirms this association. On 27 April 2011, there were 64 severe tornadoes and our clustering analysis is predominantly random with virtually no embedded linear patterns. We associate this pattern with a large number of interacting supercell thunderstorms generating tornadoes randomly in space and time. In order to better understand these associations, we also applied our approach to the Great Plains tornado outbreak of 3 May 1999. Careful studies by others have associated

  20. Spatial-Temporal Clustering of Tornadoes

    Science.gov (United States)

    Malamud, Bruce D.; Turcotte, Donald L.; Brooks, Harold E.

    2017-04-01

    The standard measure of the intensity of a tornado is the Enhanced Fujita scale, which is based qualitatively on the damage caused by a tornado. An alternative measure of tornado intensity is the tornado path length, L. Here we examine the spatial-temporal clustering of severe tornadoes, which we define as having path lengths L ≥ 10 km. Of particular concern are tornado outbreaks, when a large number of severe tornadoes occur in a day in a restricted region. We apply a spatial-temporal clustering analysis developed for earthquakes. We take all pairs of severe tornadoes in observed and modelled outbreaks, and for each pair plot the spatial lag (distance between touchdown points) against the temporal lag (time between touchdown points). We apply our spatial-temporal lag methodology to the intense tornado outbreaks in the central United States on 26 and 27 April 2011, which resulted in over 300 fatalities and produced 109 severe (L ≥ 10 km) tornadoes. The patterns of spatial-temporal lag correlations that we obtain for the 2 days are strikingly different. On 26 April 2011, there were 45 severe tornadoes and our clustering analysis is dominated by a complex sequence of linear features. We associate the linear patterns with the tornadoes generated in either a single cell thunderstorm or a closely spaced cluster of single cell thunderstorms moving at a near-constant velocity. Our study of a derecho tornado outbreak of six severe tornadoes on 4 April 2011 along with modelled outbreak scenarios confirms this association. On 27 April 2011, there were 64 severe tornadoes and our clustering analysis is predominantly random with virtually no embedded linear patterns. We associate this pattern with a large number of interacting supercell thunderstorms generating tornadoes randomly in space and time. In order to better understand these associations, we also applied our approach to the Great Plains tornado outbreak of 3 May 1999. Careful studies by others have associated

  1. Thunderstorm activity in early Earth: same estimations from point of view a role of electric discharges in formation of prebiotic conditions

    Science.gov (United States)

    Serozhkin, Yu.

    2008-09-01

    Introduction The structure and the physical parameters of an early Earth atmosphere [1], most likely, played a determining role in formation of conditions for origin of life. The estimation of thunderstorm activity in atmosphere of the early Earth is important for understanding of the real role of electrical discharges during formation of biochemical compounds. The terrestrial lightning a long time are considered as one of components determining a physical state and chemical structure of an atmosphere. Liebig in 1827 has considered a capability of nitrogen fixation at discharges of lightning [2]. Recent investigations (Lamarque et al. 1996) have achieved that production rate of NOx due to lightning at 3·106 ton/year [3]. The efficiency of electric discharges as energy source for synthesis of low molecular weight organic compounds is explained by the several factors. To them concern effect of optical radiation, high temperature, shock waves and that is especially important, pulse character of these effects. The impulse impact is essentially reduced the probability of destruction of the formed compounds. However, for some reasons is not clear the real role of electric discharges in synthesis of biochemical compounds. The discharges used in experiments on synthesis of organic substances, do not remind the discharges observable in a nature. One more aspect of a problem about a role of electric discharges in forming pre-biotic conditions on the Earth is connected with the thunderstorm activity in a modern atmosphere. This activity is connected with the presence in an atmosphere of ice crystals and existing gradient of temperature. To tell something about a degree of thunderstorm activity during the early Earth, i.e. that period, when formed pre-biotic conditions were is very difficult. Astrobiological potential of various discharges First of all the diversity of electric discharges in terrestrial atmosphere (usual lightning, lightning at eruption of volcanoes

  2. 利用信号场作深圳宝安机场的雷暴分类研究%A Study on Classification of Thunderstorm by Using the Signal Field at Shenzhen Baoan Airport

    Institute of Scientific and Technical Information of China (English)

    余岸雄; 黄嘉佑; 张焱; 白莹莹

    2012-01-01

    利用深圳宝安机场2001~2010年雷暴观测资料和NCEP/NCAR再分析资料,运用统计方法研究近10年来雷暴发生的气候特征.利用主成分分析方法提取宝安机场夏季雷暴日500hPa高度信号场共同特征,并根据主成分分析前3个模态归纳出3种易出现雷暴的天气类型:台风型,高空槽、切变线型和副热带高压型;其中近10年来副热带高压型在夏季出现的频次最高.从年际变化来看,高空槽、切变型和台风型都是呈减少趋势,而副热带高压型无明显变化趋势.%Based on the thunderstorm observation data and NCEP / NCAR reanalysis data in Shenzhen Baoan Airport for the period of 2001 to 2010; the climatic change characteristics analysis of the thunderstorms are studied by means of mathematical statistic. The common features of 500hPa-signal field of summer thunderstorms can be extracted by using the principal component analysis method. According to the first three vibration modes, the weather systems to benefit thunderstorms could be classified to three synoptic patterns (typhoon, upper trough and shear line, subtropical high). In the recent 10 years, the subtropical high pattern is the highest frequencies in summer. From the inter-annual change of view, the upper trough and shear line pattern and the typhoon pattern are on a declining trend, while the subtropical high pattern had no obvious change trend.

  3. Polarimetric and Multi-Doppler Radar Observations of Sprite-producing Storms

    Science.gov (United States)

    Lang, TImothy J.; Lyons, Walter A.; Rutledge, Steven A.; Dolan, Brenda; Cummer, Steven A.; Krehbiel, Paul; Rison, William

    2014-01-01

    Sprites are caused by luminous electrical breakdown of the upper atmosphere, and frequently occur over large mesoscale precipitation systems. Two sprite-producing storms (on 8 and 25 June) were observed in Colorado during the summer of 2012. Unlike most past studies of sprites, these storms were observed by a polarimetric radar - the CSU-CHILL facility - which provided both PPI and RHI scans of the cases. Also available were multiple-Doppler syntheses from CSU-CHILL, local NEXRAD radars, and the CSU-Pawnee radar; as well as data from the Colorado Lightning Mapping Array (COLMA), high speed cameras, and other lightning-detection instrumentation. This unique dataset provided an unprecedented look at the detailed kinematic and microphysical structures of the thunderstorms as they produced sprites, including electrical alignment signatures in the immediate location of the charge layers neutralized by sprite-parent positive cloud-to-ground lightning strokes. One of the sprite-producing cases (25 June) featured an anomalous charge structure and may serve as a model for how sprites can be produced over convection rather than the more typical stratiform regions. Also to be presented will be evidence for advection of charge into a common stratiform precipitation region (on 8 June), which was then tapped by lightning originating from multiple different convective cores to produce sprites. Depending on the outcome of the 2013 convective season, polarimetric data from additional storms that produce sprites and other transient luminous events (TLEs) may be presented.

  4. Brookhaven Linac Isotope Producer

    Data.gov (United States)

    Federal Laboratory Consortium — The Brookhaven Linac Isoptope Producer (BLIP)—positioned at the forefront of research into radioisotopes used in cancer treatment and diagnosis—produces commercially...

  5. Producing Against Poverty

    NARCIS (Netherlands)

    Ypeij, Annelou

    2000-01-01

    Producing against Poverty is an anthropological research on micro-entrepreneurs in Lima, Peru. It analyses the way micro-producers accumulate capital. The anthropological approach of the book starts with an analysis of the daily lives of the micro-producers. Its gender approach makes a comparison be

  6. TGF Ground Observations from a Winter Thunderstorm in Japan: First Ground Observation of a Multipulse TGF & Evidence of Neutron Production from a TGF

    Science.gov (United States)

    Bowers, G. S.; Smith, D. M.; Kelley, N. A.; Takahashi, S.; Ishikawa, A.; Kamogawa, M.; Heckman, S.; Cummer, S.

    2016-12-01

    On December 23rd, during a Japan Society for the Promotion of Science (JSPS) Postdoctoral Fellowship Program, the instrument GODOT (Gamma Ray Observations During Overhead Thunderstorms) observed two Terrestrial Gamma-ray Flash (TGF) events in Uchinada, Ishikawa prefecture, Japan. During the first event at 1706 UTC, 7 bursts of radiation were observed in 3 scintillator detectors over an 8 ms interval, with each burst 100 μs in duration consisting of 15-250 scintillator counts with some energies exceeding 10 MeV. Approximately 20 ms before this, we observed a smaller burst in the 3 detectors with 20 μs duration and 15 counts up to several MeV corresponding to the strongest VLF signal observed for these bursts by the Earth Networks Total Lightning Network (ENTLN) and VLF receivers operated by our collaborators at Tokyo Gakugei University. Nearby LF radio data show that each gamma ray feature corresponds to a distinct radio burst. The second event at 2020 UTC was a single, very bright burst with a decaying tail lasting > 65 ms, showing evidence of a flux of thermal neutrons via the neutron capture line at 2.2 MeV, the capture being presumably on protons in the plastic scintillation material of the detector itself. This flash included an upward positive leader from a lightning protection tower next to the Uchinada wind turbine. We will present observations of both events with constraints on the production of relativistic electrons from Monte Carlo simulations.

  7. High-Resolution Analysis Products to Support Severe Weather and Cloud-to-Ground Lightning Threat Assessments over Florida

    Science.gov (United States)

    Case, Jonathan; Spratt, Scott; Sharp, David

    2006-01-01

    The Applied Meteorology Unit (AMU) located at the Kennedy Space Center (KSC)/Cape Canaveral Air Force Station (CCAFS) implemented an operational configuration of the Advanced Regional Prediction System (ARPS) Data Analysis System (ADAS), as well as the ARPS numerical weather prediction (NWP) model. Operational, high-resolution ADAS analyses have been produced from this configuration at the National Weather Service in Melbourne, FL (NWS MLB) and the Spaceflight Meteorology Group (SMG) over the past several years. Since that time, ADAS fields have become an integral part of forecast operations at both NWS MLB and SMG. To continue providing additional utility, the AMU has been tasked to implement visualization products to assess the potential for supercell thunderstorms and significant tornadoes, and to improve assessments of short-term cloud-to-ground (CG) lightning potential. This paper and presentation focuses on the visualization products developed by the AMU for the operational high-resolution ADAS and AR.PS at the NWS MLB and SMG. The two severe weather threat graphics implemented within ADAS/ARPS are the Supercell Composite Parameter (SCP) and Significant Tornado Parameter (SIP). The SCP was designed to identify areas with supercell thunderstorm potential through a combination of several instability and shear parameters. The SIP was designed to identify areas that favor supercells producing significant tornadoes (F2 or greater intensity) versus non-tornadic supercells. Both indices were developed by the NOAAINWS Storm Prediction Center (SPC) and were normalized by key threshold values based on previous studies. The indices apply only to discrete storms, not other convective modes. In a post-analysis mode, the AMU calculated SCP and SIP for graphical output using an ADAS configuration similar to the operational set-ups at NWS MLB and SMG. Graphical images from ADAS were generated every 15 minutes for 13 August 2004, the day that Hurricane Charley approached and

  8. Boosting Farm Produce Supply

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In the wake of escalating inflation,securing farm produce supply and stablizing grain prices could help to alleviate economic pressure The Chinese Government has pledged to secure a stable supply of farm produce.According to a document released after the annual Central Rural Work Conference held on December 22-23 in Beijing,preventing short supplies of farm produce and avoiding"ex-

  9. Biologically produced sulfur

    NARCIS (Netherlands)

    Kleinjan, W.E.; Keizer, de A.; Janssen, A.J.H.

    2003-01-01

    Sulfur compound oxidizing bacteria produce sulfur as an intermediate in the oxidation of hydrogen sulfide to sulfate. Sulfur produced by these microorganisms can be stored in sulfur globules, located either inside or outside the cell. Excreted sulfur globules are colloidal particles which are stabil

  10. Properties of x-ray emission from natural and rocket triggered lightning as measured by the Thunderstorm Energetic Radiation Array (TERA)

    Science.gov (United States)

    Saleh, Ziad

    The Thunderstorm Energetic Radiation Array (TERA) is an experiment designed to measure energetic radiations (x-rays and gamma-rays) from thunderstorms and lightning. It is located at the International Center for Lightning Research and Testing (ICLRT) facility at Camp Blanding, FL. The array is integrated with the Multiple Station Experiment (MSE) which provides simultaneous measurement of electric and magnetic fields from nearby lightning. Since 2003, the facility has been operated jointly by University of Florida and Florida Institute of Technology. The array contains eight plastic, two Lanthanum Bromide (LaBr3) and 37 Sodium Iodide (NaI) detectors distributed over 25 stations covering the ˜ .5 km2 facility and centered around the rocket launch tower which is used to trigger lightning. A subset of the MSE/TERA network, consisting of 9 stations, is operated as a time of arrival network. From 2005 to 2007, MSE/TERA recorded 9 successful rocket-triggered lightning events and 16 natural flashes, all negative cloud-to-ground. In this dissertation, I present an analysis of the x-ray emission from rocket triggered and natural lightning to study their spatial and temporal variation during the leader formation. The x-rays are emitted in discrete bursts lasting for about 1 musec and observed to occur during the last 10˜100 musec of the dart leader and dart-stepped leader phase of triggered lightning and during the last 1 ms of the stepped leader phase of natural lightning, just prior to the time of the return stroke and ceases afterwards. I propose a model for the x-ray emission from a dart-stepped leader which depicts the seed electrons being accelerated near the leader tip clue to the high electric fields and following the path of the dart-stepped leader. Using detailed 3D Monte Carlo simulations, which fully model the bremsstrahlung production, electron and x-ray propagation, the model shows that the seed electrons are emitted isotropically in the azimuthal angle with

  11. A Numerical Study of Space Charge Formation Beneath Thunderstorm%雷暴云下空间电荷层形成的数值研究

    Institute of Scientific and Technical Information of China (English)

    孙安平; 言穆弘; 张义军; 郄秀书

    2001-01-01

    With a two-dimensional axissymmetric model and a ground corona discharge model, we have numerically calculated the temporal and spatial distribution of space charge density and analyzed the formation of space charge layer, especially concerning transportation mechanism for all kinds of ions, under the thunderclouds. The results show that ground point discharge is always controlled by electric structure in the low part of the thunderstorm. On the other hand, ground point discharge, in,turn, emprass the development of electric structure inside the thundercloud.%利用一个引入了地面尖端电晕放电物理过程的二维轴对称积云起电模式,讨论了雷暴云下空间电荷层的空间分布和随时间的演化规律。在模式计算上采用了"时步分离法",即在小时步上计算电导及各种反极性离子的复合作用,在大时步上计算平流、对流和湍流扩散项,对于不同的时间步长垂直方向采用不同的格距。通过模拟分析,得到了一些较为合理的结果。最后简单地讨论了本工作在以后需改进的地方。

  12. Agricultural Producer Certificates

    Data.gov (United States)

    Montgomery County of Maryland — A Certified Agricultural Producer, or representative thereof, is an individual who wishes to sell regionally-grown products in the public right-of-way. A Certified...

  13. Methods for producing diterpenes

    DEFF Research Database (Denmark)

    2015-01-01

    The present invention discloses that by combining different di TPS enzymes of class I and class II different diterpenes may be produced including diterpenes not identified in nature. Surprisingly it is revealed that a di TPS enzyme of class I of one species may be combined with a di TPS enzyme...... of class II from a different species, resulting in a high diversity of diterpenes, which can be produced....

  14. Conflicts and Identity Construction in the Drama "Thunderstorm"under the Interpersonal Relationship Management Theory%人际关系管理理论下《雷雨》中的戏剧冲突及身份建构

    Institute of Scientific and Technical Information of China (English)

    王月花

    2015-01-01

    This paper analyses the drama "Thunderstorm".It analyses interpersonal conflict in the drama and the construction of communication in the communication process using the interpersonal harmony management theory of Spencer -Oatey.%本文以话剧《雷雨》为分析语料,运用 Spencer—Oatey 的人际和谐管理理论来分析戏剧中通过对交际者面子及社交权的威胁来构成的人际冲突,以及交际过程中交际者身份的构建。

  15. Experimentally produced calf pneumonia.

    Science.gov (United States)

    Gourlay, R N; Howard, C J; Thomas, L H; Stott, E J

    1976-03-01

    Experimental pneumonia was produced in calves by the endobronchial inoculation of pneumonic lung homogenates. Irradiated homogenates produced minimal pneumonia. Ampicillin treatment of the homogenates and the experimental calves reduced the extent of pneumonia. Treatment with tylosin tartrate prevented experimental pneumonia. These results suggest that the total pneumonia was due to organisms susceptible to tylosin tartrate and that the residual pneumonia remaining after ampicillin treatment was due to organisms susceptible to tylosin tartrate but not to ampicillin. Of the organisms isolated from the lungs, the ones in this latter category most likely to be responsible are Mycoplasma dispar and ureaplasmas (T-mycoplasmas).

  16. Producing CD-ROMs.

    Science.gov (United States)

    Hyams, Peter, Ed.

    1992-01-01

    This issue presents 11 articles that address issues relating to the production of CD-ROMs. Highlights include current uses of CD-ROM; standards; steps involved in producing CD-ROMs, including data capture, conversion, and tagging, product design, and indexing; authoring; selecting indexing and retrieval software; costs; multimedia CD-ROMs; and…

  17. Producing superhydrophobic roof tiles

    Science.gov (United States)

    Carrascosa, Luis A. M.; Facio, Dario S.; Mosquera, Maria J.

    2016-03-01

    Superhydrophobic materials can find promising applications in the field of building. However, their application has been very limited because the synthesis routes involve tedious processes, preventing large-scale application. A second drawback is related to their short-term life under outdoor conditions. A simple and low-cost synthesis route for producing superhydrophobic surfaces on building materials is developed and their effectiveness and their durability on clay roof tiles are evaluated. Specifically, an organic-inorganic hybrid gel containing silica nanoparticles is produced. The nanoparticles create a densely packed coating on the roof tile surface in which air is trapped. This roughness produces a Cassie-Baxter regime, promoting superhydrophobicity. A surfactant, n-octylamine, was also added to the starting sol to catalyze the sol-gel process and to coarsen the pore structure of the gel network, preventing cracking. The application of ultrasound obviates the need to use volatile organic compounds in the synthesis, thereby making a ‘green’ product. It was also demonstrated that a co-condensation process effective between the organic and inorganic species is crucial to obtain durable and effective coatings. After an aging test, high hydrophobicity was maintained and water absorption was completely prevented for the roof tile samples under study. However, a transition from a Cassie-Baxter to a Wenzel state regime was observed as a consequence of the increase in the distance between the roughness pitches produced by the aging of the coating.

  18. The radio wave as a source of free energy for the synthesis of organic molecules into the droplets of thunderstorm cloud

    Science.gov (United States)

    Gusev, Victor

    This paper advances the hypothesis stating that low-molecular-weight organic compounds, precursors of living cell components, may be synthesized from inorganic oxides in the presence of alternating electromagnetic field as an energy source. This synthesis can be implemented in the water droplets hovering in a thunderstorm cloud of the Earth or another planet prebiotic atmosphere. A stroke of lightning is known to excite a broad spectrum of electromagnetic waves. These, in turn, can excite the Langmuir vibrations of protons in water droplets. The molecular mechanism of this process has been described in detail [1, 2]. For the convenience of simulation, we will consider the ideal case, namely, that the Langmuir proton vibrations possess, on average, a spherical symmetry. This idealization does not contradict the physics of the process: since the object is spherically symmetrical, the geometry of stationary vibration processes taking place in this object should also possess a spherical symmetry. We will assume that the form of the Langmuir vibrations is represented by periodic thickening and thinning of protons in the central area of the droplet. We will discuss processes in droplets whose radius Ro=510-5 cm, which corresponds to the average microbe size. The activation energies of most homogeneous chemical reactions fall in the 1-3 eV range; therefore, in the central area with the radius R=Ro/2, the energy of protons is sufficient both for activating the reactions and for the synthesis itself to proceed. The calculations carried out in [1, 2] allow one to estimate the required amplitude E 700 V/m) and frequency 6109 Hz) for an electromagnetic wave able to excite the Langmuir vibrations of protons with an energy of about 3 eV. The time spent for the whole process of synthesis of primary organic matter is much shorter than geological periods; under conditions formulated above, this time is only 1 s. An advantage of this model is the possibility of its real

  19. The interaction of large scale and mesoscale environment leading to formation of intense thunderstorms over Kolkata. Part I: Doppler radar and satellite observations

    Indian Academy of Sciences (India)

    P Mukhopadhyay; M Mahakur; H A K Singh

    2009-10-01

    The weather systems that predominantly affect the eastern and northeastern parts of India during the pre-monsoon summer months (March,April and May)are severe thunderstorms,known as Nor ’westers.The storms derive their names from the fact that they frequently strike cities and towns in the southern part of West Bengal in the afternoon from the north-west direction while traveling far from its place of genesis over the Bihar plateau.The storms are devastating in nature particularly due to strong (gusty)winds,heavy rains and hails associated with it.Although these storms are well known for its power of causing damages,studies on them are relatively few due to their small size and sparse network of observations.To address this important issue,the evolution of two Nor ’westers of 12 March and 22 May 2003 over Kolkata is studied in detail in this paper using hourly Doppler weather radar (DWR)observations and high resolution Meteosat-5 imageries.In addition,supporting meteorological reports are used to find the large scale conditions that influence the moisture convergence and vertical wind shear.The genesis of both the storms is found to be over Bihar –Jharkhand region and beyond the range of the DWR.The satellite observations are found to be useful in identifying the location and initiation of the storms.The movements of the storms are captured by the DWR estimated vertical cross-section of reflectivities.The Doppler estimate shows that the 12 March storm had a vertical extent of about 10 –12 km at the time of maturity and that of 22 May reaching up to 18 km signifying deep convection associated with these events.The genesis, maturity and dissipation are well brought out by the hourly DWR and satellite imageries.The DWR observations suggest that the systems move at a speed of 20 –25 m/s.The DWR estimated precipitation shows a detailed spatial distribution around Kolkata with several localized zones of heavy rain and this is found to be well supported by

  20. Assessing Patterns in the Surface Electric Field Prior to First CG Flashes and After Last CG Flashes in Air-Mass Thunderstorms

    Science.gov (United States)

    Williams, D. E.; Beasley, W. H.; Hyland, P. T.

    2007-12-01

    In an effort to elicit patterns in the temporal and spatial evolution of the contours of surface electric field relevant to the occurrence of cloud-to-ground (CG) lightning, we have analyzed data from the network of 31 electric-field mills jointly operated by the John F. Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS). To identify cases of interest, we used lightning ground-strike data, maps of in-cloud lightning discharges, rainfall data, and radar data. In particular, we have focused on two critical problems: 1) estimation of when and where the first CG flash in a storm might occur and 2) assessment of the likelihood of CG flashes occurring late in a storm after a long period without a CG flash. Our long-term goal is to understand the evolution of surface contours of electric field for periods of 30 minutes or more before the first flash of any kind and 30 minutes or more before and after the last flash of any kind. For practical reasons, we are reporting here on analysis of data for periods of 30 minutes before the first CG flash and 30 minutes after the last CG flash in each storm of interest. We have analyzed electric-field data from isolated air-mass convective storms that developed over KSC/CCAFS from late May through early September, 2004-2006. To identify thunderstorms that fit the air-mass, or "pop-up" criteria, we started by examining rainfall and CG lightning data, then looked at radar data. Then, for the storms selected, we performed a two-pass Barnes objective analysis on the electric-field data. Each analysis cycle resulted in one contour plot of 20-second averaged data, yielding 90 plots for each 30 minute interval, which we then animated. This resulted in 58 animations of the field contours prior to first CG flashes and 62 animations of the field contours after last CG flashes. Preliminary impressions from examinations of these cases suggest that the electric-field contours before the first flash exhibit a smooth transition

  1. Method of producing imines

    Science.gov (United States)

    Sithambaram, Shanthakumar; Son, Young-Chan; Suib, Steven L.

    2008-04-08

    A method for forming an imine comprises reacting a first reactant comprising a hydroxyl functionality, a carbonyl functionality, or both a hydroxyl functionality and a carbonyl functionality with a second reactant having an amine functionality in the presence of ordered porous manganese-based octahedral molecular sieves and an oxygen containing gas at a temperature and for a time sufficient for the imine to be produced.

  2. 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.

  3. Precipitation Field and Intrastorm Flow of Supercell Convective Storms.

    Science.gov (United States)

    1981-08-01

    3.68 2.75 2.26stretchin .. Export. / Suare V=-A*EP’ R<Core V-A 2/R RCore Location Toward/Away From Radar R.S. @ 44-39-34-29 km -2.61 -1.74 -1.37 -1.18...0.09 0.05 54-59-64-69 km 6.64 3.87 2.76 2.16 56-61-66-71 km -4.65 -2.78 -1.95 -1.48 A max-mmnA max-mi 11.85 7.35 5.49 4.52stretching, Expon./ Suare

  4. Produce Sanitation System Evaluation

    Science.gov (United States)

    2011-05-01

    the  amount in each product’s case.     Table 2: Produce Packaging  Product   Amount  Tomatoes  25 lb  Broccoli   20 lb  Iceberg lettuce  6 heads...aftertaste through it computer-based cleansing process and use of a citrus-based “green” cleansing product . Microbiologists from CFD performed...several tests of bacteria counts and pathogen log rate reductions of various FF&V products before and after they passed through the sanitizing sink process

  5. Producing Civil Society

    DEFF Research Database (Denmark)

    Feldt, Liv Egholm; Hein Jessen, Mathias

    Since the beginning of the 1990’s, civil society has attracted both scholarly and political interest as the ‘third sphere’ outside the state and the market not only a normatively privileged site of communication and ‘the public sphere’, but also as a resource for democratization processes...... of the century. 2, the laws and strategies of implementing regarding the regulation of civil societal institutions (folkeoplysningsloven) since the 1970’s this paper shows how civil society in 20th century Denmark was produced both conceptually and practically and how this entailed a specific vision and version...

  6. Structure and evolution of flash flood producing storms in a small urban watershed

    Science.gov (United States)

    Yang, Long; Smith, James; Baeck, Mary Lynn; Smith, Brianne; Tian, Fuqiang; Niyogi, Dev

    2016-04-01

    The objective of this study is to examine the structure and evolution of storms that produce flash floods in "small" urban watersheds. The study site is Harry's Brook, a 1.1 km2 urban watershed in Princeton, New Jersey. A catalog of 15 storms is developed for Harry's Brook based on paired observations of streamflow and rainfall. Lagrangian analyses of storm properties are based on storm tracking procedures utilizing 3-D radar reflectivity observations from the KDIX (Fort Dix, New Jersey) Weather Surveillance Radar, 1988 Doppler. Analyses focus on the storm elements that were responsible for the peak rainfall rates over the watershed. The 22 July 2006 storm, which produced the record flood peak in the catalog (a unit discharge of 26.8 m3 s-1 km-2) was characterized by thunderstorm cells that produced more than 50 cloud-to-ground lightning strikes and "collapsed" over Harry's Brook. The 3 June 2006 storm, which produced the third largest flood peak (a unit discharge of 11.1 m3 s-1 km-2), was a "low-echo centroid" storm with no lightning. We use cloud-to-ground flash rate, echo top height, maximum reflectivity, and height of maximum reflectivity as key variables for characterizing convective intensity. Storm motion is examined through a time series of storm speed and direction. The 22 July 2006 and 3 June 2006 storms provide end-members of storm properties, centering on "convective intensity," which are associated with flash flooding in small urban watersheds. Extreme 1-15 min rainfall rates are produced by warm season convective systems at both ends of the convective intensity spectrum.

  7. Power Producer Production Valuation

    Directory of Open Access Journals (Sweden)

    M. Kněžek

    2008-01-01

    Full Text Available The ongoing developments in the electricity market, in particular the establishment of the Prague Energy Exchange (PXE and the associated transfer from campaign-driven sale to continuous trading, represent a significant change for power companies.  Power producing companies can now optimize the sale of their production capacities with the objective of maximizing profit from wholesale electricity and supporting services. The Trading Departments measure the success rate of trading activities by the gross margin (GM, calculated by subtracting the realized sales prices from the realized purchase prices and the production cost, and indicate the profit & loss (P&L to be subsequently calculated by the Control Department. The risk management process is set up on the basis of a business strategy defining the volumes of electricity that have to be sold one year and one month before the commencement of delivery. At the same time, this process defines the volume of electricity to remain available for spot trading (trading limits. 

  8. On the Application of Duet in Huangmei Opera——A Case Study ofThunderstorm%黄梅戏唱腔中"对板"的运用——以黄梅戏《雷雨》为例

    Institute of Scientific and Technical Information of China (English)

    张静

    2015-01-01

    本文以黄梅戏《雷雨》的唱腔为研究对象,对对板唱腔音乐进行分析阐述.通过对这种创作手法的分析,感受作曲家的戏曲创作经验、创作思想,从中得到启发并加以借鉴,从而创作出更多适合当前社会需要的戏曲音乐作品.%The paper focuses on the tune of Huangmei OperaThunderstorm. It analyses the duet music applied in Huangmei Opera, helps experience the composer's feeling and thinking, and hopes that more music will be created to meet the demand of the society.

  9. Florida Agriculture - Utilizing TRMM to Analyze Sea Breeze Thunderstorm Patterns During El Nino Southern Oscillations and Their Effects Upon Available Fresh Water for South Florida Agricultural Planning and Management

    Science.gov (United States)

    Billiot, Amanda; Lee, Lucas; McKee, Jake; Cooley, Zachary Clayton; Mitchell, Brandie

    2010-01-01

    This project utilizes Tropical Rainfall Measuring Mission (TRMM) and Landsat satellite data to assess the impact of sea breeze precipitation upon areas of agricultural land use in southern Florida. Water is a critical resource to agriculture, and the availability of water for agricultural use in Florida continues to remain a key issue. Recent projections of statewide water use by 2020 estimate that 9.3 billion gallons of water per day will be demanded, and agriculture represents 47% of this demand (Bronson 2003). Farmers have fewer options for water supplies than public users and are often limited to using available supplies from surface and ground water sources which depend in part upon variable weather patterns. Sea breeze thunderstorms are responsible for much of the rainfall delivered to Florida during the wet season (May-October) and have been recognized as an important overall contributor of rainfall in southern Florida (Almeida 2003). TRMM satellite data was used to analyze how sea breeze-induced thunderstorms during El Nino and La Nina affected interannual patterns of precipitation in southern Florida from 1998-2009. TRMM's Precipitation Radar and Microwave Imager provide data to quantify water vapor in the atmosphere, precipitation rates and intensity, and the distribution of precipitation. Rainfall accumulation data derived from TRMM and other microwave sensors were used to analyze the temporal and spatial variations of rainfall during each phase of the El Nino Southern Oscillation (ENSO). Through the use of TRMM and Landsat, slight variations were observed, but it was determined that neither sea breeze nor total rainfall patterns in South Florida were strongly affected by ENSO during the study period. However, more research is needed to characterize the influence of ENSO on summer weather patterns in South Florida. This research will provide the basis for continued observations and study with the Global Precipitation Measurement Mission.

  10. Study of secondary electrons and positrons produced by Terrestrial Gamma-ray Flashes

    Science.gov (United States)

    Sarria, D.; Blelly, P.-L.; Forme, F.

    2015-12-01

    Terrestrial Gamma ray Flahes are emissions of X and gamma rays, correlated to thunderstorms. By interacting with the atmosphere, the photons produce a large number of electrons and positrons. Some of these reach altitudes above ˜ 100 km that their interactions with the atmosphere become negligible, and they are then guided by Earth's magnetic field lines, forming the so called Terrestrial Electron Beams. The GBM instrument of the Fermi Space Telescope made a particularly interesting measurement of such an event that happened the 12/09/2009. We perform Monte-Carlo simulations to study this event in detail and we focus on the resulting time histograms. In agreement with previous works, we show that the histogram measured by Fermi GBM can be reproduced from simulations. We then show that the time histogram can be decomposed into three populations of leptons, coming from the hemisphere opposite from the TGF, and mirroring back to the satellite with interactions with the atmosphere or not, and that these we can be clearly distinguished both with their pitch angles.

  11. Methods for producing complex films, and films produced thereby

    Energy Technology Data Exchange (ETDEWEB)

    Duty, Chad E.; Bennett, Charlee J. C.; Moon, Ji -Won; Phelps, Tommy J.; Blue, Craig A.; Dai, Quanqin; Hu, Michael Z.; Ivanov, Ilia N.; Jellison, Jr., Gerald E.; Love, Lonnie J.; Ott, Ronald D.; Parish, Chad M.; Walker, Steven

    2015-11-24

    A method for producing a film, the method comprising melting a layer of precursor particles on a substrate until at least a portion of the melted particles are planarized and merged to produce the film. The invention is also directed to a method for producing a photovoltaic film, the method comprising depositing particles having a photovoltaic or other property onto a substrate, and affixing the particles to the substrate, wherein the particles may or may not be subsequently melted. Also described herein are films produced by these methods, methods for producing a patterned film on a substrate, and methods for producing a multilayer structure.

  12. Large Charge Moment Change Lightning in an Oklahoma Mesoscale Convective System

    Science.gov (United States)

    Lang, Timothy J.; Cummer, Steven; Petersen, Danyal; Flores-Rivera, Lizxandra; Lyons, Walt; MacGorman, Donald; Beasley, William

    2014-01-01

    On 31 May 2013, a line of severe thunderstorms developed during the local afternoon in central Oklahoma, USA. One of the supercells produced the El Reno tornado, which caused significant damage and killed several people. During the 2300 UTC hour (during the mature supercell stage and just after the tornado began), the storm produced several positive cloud-to-ground (+CG) lightning strokes that featured large (> 100 C km) impulse charge moment changes (iCMCs; charge moment during the first 2 ms after the return stroke). These discharges occurred mainly in convection, in contrast to the typical pattern of large-CMC and sprite-parent +CGs occurring mainly in stratiform precipitation regions. After this time, the line of thunderstorms evolved over several hours into a large mesoscale convective system (MCS). By the 0700 UTC hour on 1 June 2013, the large-CMC pattern had changed markedly. Large-CMC negative CGs, which were absent early in the storm's lifetime, occurred frequently within convection. Meanwhile, large-CMC +CGs had switched to occurring mainly within the broad stratiform region that had developed during the intervening period. The evolution of the large-CMC lightning in this case will be examined using a mix of national mosaics of radar reflectivity, the Oklahoma Lightning Mapping Array (OKLMA), the Charge Moment Change Network (CMCN), and the National Lightning Detection Network (NLDN). A major goal of this study is understanding how storm structure and evolution affected the production of large-CMC lightning. It is anticipated that this will lead to further insight into how and why storms produce the powerful lightning that commonly causes sprites in the upper atmosphere.

  13. Producing Runaway Stars

    Science.gov (United States)

    Kohler, Susanna

    2016-07-01

    How are the hypervelocity stars weve observed in our galaxy produced? A recent study suggests that these escapees could be accelerated by a massive black hole in the center of the Large Magellanic Cloud.A Black Hole SlingshotSince their discovery in 2005, weve observed dozens of candidate hypervelocity stars stars whose velocity in the rest frame of our galaxy exceeds the local escape velocity of the Milky Way. These stars present a huge puzzle: how did they attain these enormous velocities?One potential explanation is known as the Hills mechanism. In this process, a stellar binary is disrupted by a close encounter with a massive black hole (like those thought to reside at the center of every galaxy). One member of the binary is flung out of the system as a result of the close encounter, potentially reaching very large velocities.A star-forming region known as LHA 120-N 11, located within the LMC. Some binary star systems within the LMC might experience close encounters with a possible massive black hole at the LMCs center. [ESA/NASA/Hubble]Blame the LMC?Usually, discussions of the Hills mechanism assume that Sagittarius A*, the supermassive black hole at the center of the Milky Way, is the object guilty of accelerating the hypervelocity stars weve observed. But what if the culprit isnt Sgr A*, but a massive black hole at the center of the Large Magellanic Cloud (LMC), one of the Milky Ways satellite galaxies?Though we dont yet have evidence of a massive black hole at the center of the LMC, the dwarf galaxy is large enough to potentially host one as large as 100,000 solar masses. Assuming that it does, two scientists at the University of Cambridge, Douglas Boubert and Wyn Evans, have now modeled how this black hole might tear apart binary star systems and fling hypervelocity stars around the Milky Way.Models for AccelerationBoubert and Evans determined that the LMCs hypothetical black hole could easily eject stars at ~100 km/s, which is the escape velocity of the

  14. Quality of milk produced by small and large dairy producers

    Directory of Open Access Journals (Sweden)

    Jose Carlos Ribeiro Junior

    2015-04-01

    Full Text Available The aim of this study was to compare the microbiological and physicochemical quality of raw milk produced by small and large dairy producers in Paraná, Brazil. Samples of raw milk were collected from small (49 and large (21 dairy producers. Dairy farms were characterized by observation and application of questionnaires. The total bacterial count (TBC was obtained by flow cytometry and Petrifilm® AC, while the somatic cell count (SCC was obtained by only flow cytometry. The content of fat, proteins, lactose, and solids in the mil were determined by infrared. Differences were observed in the techniques employed by small and large dairy producers, which may have influenced the microbiological quality of raw milk. Milk contamination significantly greater in milk produced by small farmers, which is evident from the average TBC of 3.8 × 106 CFU/mL obtained from milk produced by small farmers as compared to the TBC of 1.5 × 104 CFU/mL obtained from larger dairy farms. Twenty-four (49% small diary producers are no-compliant with the current standards for microbiological quality of refrigerated raw milk established by the law, while all larger producers were compliant with the standards. The average SCC of milk obtained from small producers was 2.2 × 105 SC/mL, while that of large milk producers was 3.9 × 105 SC/mL. Milk produced by small producers contained significantly higher fat, protein, lactose, and solids content. Milk produced by larger dairy farmers was mainly composed of lactose. In brief, the microbiological quality of milk from larger producers was higher, and SCC is proportional to the productivity. In addition, milk obtained from small dairy producers has a higher solid content.

  15. English Organic Producer Survey 2013

    OpenAIRE

    Catherine L. Gerrard; Padel, Susanne; Lampkin, Nic

    2014-01-01

    This report summarises the results of a survey carried out with English organic producers in November and December 2013 as part of the Organic Data Network Project. There are approximately 2724 English organic producers and 223 of these participated in the survey, a response rate of just over 8%. The sample is not representative of the total population of English organic producers, see the data collection and analysis section for more details, but gives a snapshot of the situation for...

  16. DOES ELECTRIC CAR PRODUCE EMISSIONS?

    Directory of Open Access Journals (Sweden)

    Vladimír RIEVAJ

    2017-03-01

    Full Text Available This article focuses on the comparison of the amount of emissions produced by vehicles with a combustion engine and electric cars. The comparison, which is based on the LCA factor results, indicates that an electric car produces more emissions than a vehicle with combustion engine. The implementation of electric cars will lead to an increase in the production of greenhouse gases.

  17. User producer interaction in context

    NARCIS (Netherlands)

    Nahuis, R.; Moors, E.H.M.; Smits, R.E.H.M.

    2012-01-01

    User producer interaction (UPI) increases chances for successful innovations. It is not always clear, however, what type of interaction is necessary in a particular context. This article identifies seven different types of UPI: constructing linkages, broadening, characterizing users, upstream

  18. Methods of producing transportation fuel

    Science.gov (United States)

    Nair, Vijay; Roes, Augustinus Wilhelmus Maria; Cherrillo, Ralph Anthony; Bauldreay, Joanna M.

    2011-12-27

    Systems, methods, and heaters for treating a subsurface formation are described herein. At least one method for producing transportation fuel is described herein. The method for producing transportation fuel may include providing formation fluid having a boiling range distribution between -5.degree. C. and 350.degree. C. from a subsurface in situ heat treatment process to a subsurface treatment facility. A liquid stream may be separated from the formation fluid. The separated liquid stream may be hydrotreated and then distilled to produce a distilled stream having a boiling range distribution between 150.degree. C. and 350.degree. C. The distilled liquid stream may be combined with one or more additives to produce transportation fuel.

  19. The Meteorology of Storms that Produce Narrow Bipolar Events

    Science.gov (United States)

    Lang, Timothy; McCaul, Bill; Fuchs, Brody; Cummer, Steve

    2013-01-01

    Narrow Bipolar Event's (NBE) are compact ( 10 kW in VHF), and impulsive (approx 10 micro s) electrical discharges in thunderstorms, also known as compact intracloud discharges (CIDs). Can be either positive or negative polarity and have distinctive broadband waveform signatures sometimes confused for +CGs in the past by NLDN and other networks. NBEs are related to lightning but are likely optically "dark". As revealed by VHF sensors (both satellite and ground): (1) The most powerful lightning-­-related VHF sources observed (2) Tend to occur at the beginning of intracloud discharges (3) Difficult to estimate altitude properly due to receiver saturation.

  20. Price satisfaction and producer loyalty

    DEFF Research Database (Denmark)

    Mutonyi, Sarah; Beukel, Karin; Gyau, Amos

    2016-01-01

    Purpose The purpose of this paper is to investigate which dimensions of price satisfaction influence producers’ trust in buyers and assess the mediating role of such trust in the relationship between price satisfaction and producer loyalty in fresh fruit supply chains. Design/methodology/approach......Purpose The purpose of this paper is to investigate which dimensions of price satisfaction influence producers’ trust in buyers and assess the mediating role of such trust in the relationship between price satisfaction and producer loyalty in fresh fruit supply chains. Design...... reliability, and relative price are dimensions of price satisfaction that affect producers’ trust in the buyer. Moreover, trust between the producer and the buyer is found to be a strong mediator between price satisfaction and producer loyalty. The findings support recent studies about trust and its mediating...... between the multi-dimensional nature of price satisfaction and producer loyalty with trust as a mediating variable in the business-to-business (B2B) context. Although B2B relationships have been shown to be of great importance for smallholders in enhancing business performance with their buyers, little...

  1. Producing liquid fuels from biomass

    Science.gov (United States)

    Solantausta, Yrjo; Gust, Steven

    The aim of this survey was to compare, on techno-economic criteria, alternatives of producing liquid fuels from indigenous raw materials in Finland. Another aim was to compare methods under development and prepare a proposal for steering research related to this field. Process concepts were prepared for a number of alternatives, as well as analogous balances and production and investment cost assessments for these balances. Carbon dioxide emissions of the alternatives and the price of CO2 reduction were also studied. All the alternatives for producing liquid fuels from indigenous raw materials are utmost unprofitable. There are great differences between the alternatives. While the production cost of ethanol is 6 to 9 times higher than the market value of the product, the equivalent ratio for substitute fuel oil produced from peat by pyrolysis is 3 to 4. However, it should be borne in mind that the technical uncertainties related to the alternatives are of different magnitude. Production of ethanol from barley is of commercial technology, while biomass pyrolysis is still under development. If the aim is to reach smaller carbon dioxide emissions by using liquid biofuels, the most favorable alternative is pyrolysis oil produced from wood. Fuels produced from cultivated biomass are more expensive ways of reducing CO2 emissions. Their potential of reducing CO2 emissions in Finland is insignificant. Integration of liquid fuel production to some other production line is more profitable.

  2. Shiga Toxin Producing Escherichia coli.

    Science.gov (United States)

    Bryan, Allen; Youngster, Ilan; McAdam, Alexander J

    2015-06-01

    Shiga toxin-producing Escherichia coli (STEC) is among the common causes of foodborne gastroenteritis. STEC is defined by the production of specific toxins, but within this pathotype there is a diverse group of organisms. This diversity has important consequences for understanding the pathogenesis of the organism, as well as for selecting the optimum strategy for diagnostic testing in the clinical laboratory. This review includes discussions of the mechanisms of pathogenesis, the range of manifestations of infection, and the several different methods of laboratory detection of Shiga toxin-producing E coli.

  3. Producing miniature threads. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Gillespie, L.K.; Robb, J.M.

    1981-11-01

    Miniature precision actuators, timers, and switches typically utilize miniature threads to provide convenient assembly, disassembly and adjustment. Thread rolling provides high-quality external threads with greater strength and lower cost than other thread-producing techniques. Tap breakage is a significant problem when 0.5 and 0.6 Unified National Miniature (UNM) threads must be produced in hard materials such as SAE K95100 high-permeability magnetic steel. Aluminum parts can be tapped with no difficulty in these sizes. Stainless steel 0.5 UNM screws break at loads of 21 lb (53 N). Thread failure occurs at thread heights of 62% full thread or lower.

  4. 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.

  5. 语气隐喻的文体功能——以《雷雨》为例的认知文体分析%The Stylistic Functions of Mood Metaphors——Cognition Stylistic Analysis in Thunderstorm

    Institute of Scientific and Technical Information of China (English)

    陈柯妮

    2011-01-01

    在系统功能语言学框架内,辅之以言语行为学说,探讨了《雷雨》中疑问语气构成的语气隐喻的文体功能。认为剧中疑问语气构成的语气隐喻主要表达祈使语气中的命令、请求功能以及陈述语气中的指责功能。这类语气隐喻有礼貌倾向,但当疑问语气传达指责意义时,语气隐喻往往具有讥讽意味。此外,这类隐喻还反映了戏剧人物之间的权势关系。%Within the framework of Systemic Functional Linguistics and with the assistance of Speech Act notion,the mood metaphors formed by a series of interrogative sentences in modern Chinese drama Thunderstorm are discussed.It is found that such mood metaphors coming from the drama's interrogative mood have three main functions: the function of order and request in imperative mood,as well as the function of criticism in declarative mood.Such metaphors are politely oriented,but contain ironical implications when criticizing others.Besides,it is also pointed out that as a kind of interpersonal metaphors,they are good at revealing the power relationships among characters of the play.

  6. Stylistic Functions of Modality Metaphors in Thunderstorm%情态隐喻的文体功能——《雷雨》的认知文体分析

    Institute of Scientific and Technical Information of China (English)

    陈柯妮

    2012-01-01

    The present study is an analysis of stylistic functions of modality metaphors in Thunderstorm. We start with a brief introduction to the basic notions of mod',dity metaphor, and then the modality metaphor patterns and their connection with the power relations of the characters are revealed. The discussion is the mixture of the 4 parameters of the modality metaphor-- orientation, value, polarity and type, and two pairs of elements of power relations-sympathy/alienation,dominance/balance. It is found that the modality metaphor is capable of revealing power relations on the play, and moreover, contrast to the claims by some researchers, the metaphor is not necessarily polite signal, but rather indication of power and control over others.%本项研究是关于情态隐喻的文体功能的探讨。首先,介绍了情态隐喻的基本概念及其四个变量:向度、价值,归一度和类型等,随后,对《雷雨》人物话语中总的情态隐喻状况以及四个变量特征进行了形态描述,并结合人物权势关系的四个雏度——同感与间离、控制与均势来揭示情态隐喻的文体效应。从而发现,情态隐喻可以有效地揭示戏剧人物之间的各种权势关系。此外,它并不像有些学者断言的那样,是一种表示礼貌的间接言语行为,相反,它更多地与主观、权势与控制相关联。

  7. Socio-pragmatic Approach to the Variation of the Address Terms:A case study of The Thunderstorm%称呼语变异的社会语用原则--以话剧《雷雨》为例

    Institute of Scientific and Technical Information of China (English)

    任风雷

    2015-01-01

    曹禺的《雷雨》中四凤的称呼语变异特点表明,称呼语的变异具有临时性和多变性,但是仍受到交际原则和人际关系的约束。“常规”人际关系决定称呼语形式,但是由于交际目的和交际场合导致人际关系“瞬变”,称呼语必须相应变化,以顺应人际关系和交际原则。因此,偏离常规的称呼语是人际关系、交际场合和交际原则的交互作用的结果。%This paper analyzes the variation of the address terms of the heroine, Sifeng, from The Thunderstorm by Cao Yu and finds that the variability and spontaneity of the unconventional forms of the address terms are still subjected to the communicative principles and the interpersonal relationships.It then points out that the convention-al interpersonal relationship determines the choice of the address forms, though sensitive to the changes of the com-municative intention and the communicative contexts, causing the instant variation of the interpersonal relations, and accordingly the variation of the address forms so as to adapt to the interpersonal relationship and communicative principles.It finally concludes that unconventional address forms result from the interactive effect among the inter-personal relationship, communicative context and the communicative principles.

  8. 《榆树下的欲望》和《雷雨》中人物的欲望悲剧比较%A Comparative Study of Desire Tragedy in Desire under the Elms and Thunderstorm

    Institute of Scientific and Technical Information of China (English)

    秦燕燕

    2012-01-01

    尤金·奥尼尔的《榆树下的欲望》和曹禺的《雷雨》展示了人类共通的生存欲望和精神欲望的悲剧。这种共通性主要表现在戏剧中人物各自的欲望追求与毁灭的悲剧、自我追寻与认定的精神追求失败的悲剧。生存欲望使他们苦苦挣扎却不得解脱,精神追求的失败使他们丧失正常的人性,乱伦、弑父、杀子的欲望成为他们共同的特性,不可知的命运主宰着奋力追寻的人,他们一个个走向毁灭。%Eugene O' Neal' s Desire under the Elms and Cao Yu's Thunderstorm shows the survival of the human common desire and spiritual tragedy of desire. This commonality is mainly manifested in the tragedy of the characters' desire of existence and pursuit; the failure of the psychical tragedy of pursuit themselves and identify themselves. Survival desire makes them struggle bitterly but not free; the failure of the psychical pursuit makes them lose their normal human nature. The desire that incest, patricide, kill the child has become their common characteristics. The unknown fates dominate the people who seek for themselves hardly, but in a way of de- struction.

  9. The Top Theological Degree Producers

    Science.gov (United States)

    Diverse: Issues in Higher Education, 2012

    2012-01-01

    Each year, "Diverse: Issues in Higher Education" publishes a list of the Top 100 producers of associate, bachelor's and graduate degrees awarded to minority students based on research conducted by Dr. Victor M. H. Borden, professor of educational leadership and policy studies at Indiana University Bloomington. This year, for the first…

  10. A new producer of mevastatin

    Institute of Scientific and Technical Information of China (English)

    Chu; Yiwen; Yang; Xi

    1999-01-01

    Mevastatin (compactin)was isolated form culture broth of a fungal strain SIIA-F3933,The strain SIIA-F3933 was isolated from a soil sample collected in Putuo mountain,Zhejiang Province,P,R.China,It was identified as Penicillium janczewskii Zaleski based on its cultural and morphological characteristics and was regarded as a new producer of mevastatin,。

  11. 基于大气层结和雷暴演变的闪电和降水关系%Relationship Between Lightning and Precipitation Based on Classification of Atmospheric Stratification and Development of Thunderstorm

    Institute of Scientific and Technical Information of China (English)

    王婷波; 郑栋; 张义军; 姚雯; 张文娟

    2014-01-01

    A total of 28 thunderstorms occurring in and around Beijing area from 2006 to 2008 are picked to in-vestigate the relationship between total lightning (observed by SAFIR3000)and convective precipitation (by radar inversion).These cases are classified according to parameters of the atmospheric stratification where they are generated and the reflectivity of radar.The quantitative results can provide a reference for the applications of lightning data on severe weather warning and precipitation estimation.The lightning forecast can also be improved by assimilating the relationship between the hydrometeors and the lightning activities to the numerical prediction models.The analysis can extend the application field of the lightning data. The results show that the average convective rain yields per flash is 1.92×107 kg·fl-1 on the whole, while the linear correlation coefficient between the total lightning frequency and convective precipitation is 0.584.Total lightning frequency (expressed by F with the time space being 6 min)can be used to calculate the amount of convective precipitation with the equation R=(2.813×108 )+(4.570×10 6 )F .A total of 28 thunderstorms are classified according to the convective available potential energy (E CAP )and lifting index I L of the atmospheric stratification where they are generated.It is explored that strong instability of at-mospheric stratification tends to be associated with smaller precipitation and more pronounced correlation between total lightning and precipitation.Of which,the classification of E CAP no less than 1600 J ·kg-1 has the correlation coefficient of 0.837,the total lightning frequency can be used to calculate the amount of convective precipitation with the equation of R=(1.620×108 )+(5.478 ×10 6 )F .While the classification of I L no less than 4 K has the correlation coefficient of 0.853,the total lightning frequency can be used to calculate the area of the amount of convective precipitation with the equation

  12. Method for producing hydrophobic aerogels

    Science.gov (United States)

    Hrubesh, Lawrence W.; Poco, John F.; Coronado, Paul R.

    1999-01-01

    A method for treating a dried monolithic aerogel containing non-dispersed particles, with an organometallic surface modifying agent to produce hydrophobic aerogels. The dried, porous hydrophobic aerogels contain a protective layer of alkyl groups, such as methyl groups, on the modified surfaces of the pores of the aerogel. The alkyl groups at the aerogel surface typically contain at least one carbon-metal bond per group.

  13. Wall force produced during disruptions

    Science.gov (United States)

    Strauss, H.; Paccagnella, R.; Breslau, J.

    2009-11-01

    The study of disruptions is of great importance for ITER. Previous work on disruptions [1] is extended to compute toroidally asymmetric wall force in ITER, using the M3D code. The disruptions are produced by n = 1 resistive wall modes or external kink modes. A thin wall resistive boundary model is used to calculate the wall forces. The symmetric wall force, produced by a VDE, and the asymmetric wall force, produced by n = 1 modes, are comparable in magnitude. It is found that the asymmetric and axisymmetric forces scale with the growth rate of the instability multiplied by the square of the current divided by magnetic field. A similar scaling was reported for VDEs in JET [2]. Numerically, the study of disruptions is very challenging. In the M3D extended MHD code, dealiasing was applied in the toroidal direction. Advection terms were treated with a numerical upwind method. These techniques provided sufficient numerical stability to simulate entire disruption events. [4pt] [1] R. Paccagnella, H. R. Strauss, and J. Breslau, Nucl. Fusion (2009) 49 035003. [2] V. Riccardo, T. C. Hender, P. J. Lomas, et al., Plasma Phys. Control. Fusion (2004)

  14. Endocrine cells producing regulatory peptides.

    Science.gov (United States)

    Solcia, E; Usellini, L; Buffa, R; Rindi, G; Villani, L; Zampatti, C; Silini, E

    1987-07-15

    Recent data on the immunolocalization of regulatory peptides and related propeptide sequences in endocrine cells and tumors of the gastrointestinal tract, pancreas, lung, thyroid, pituitary (ACTH and opioids), adrenals and paraganglia have been revised and discussed. Gastrin, xenopsin, cholecystokinin (CCK), somatostatin, motilin, secretin, GIP (gastric inhibitory polypeptide), neurotensin, glicentin/glucagon-37 and PYY (peptide tyrosine tyrosine) are the main products of gastrointestinal endocrine cells; glucagon, CRF (corticotropin releasing factor), somatostatin, PP (pancreatic polypeptide) and GRF (growth hormone releasing factor), in addition to insulin, are produced in pancreatic islet cells; bombesin-related peptides are the main markers of pulmonary endocrine cells; calcitonin and CGRP (calcitonin gene-related peptide) occur in thyroid and extrathyroid C cells; ACTH and endorphins in anterior and intermediate lobe pituitary cells, alpha-MSH and CLIP (corticotropin-like intermediate lobe peptide) in intermediate lobe cells; met- and leu-enkephalins and related peptides in adrenal medullary and paraganglionic cells as well as in some gut (enterochromaffin) cells; NPY (neuropeptide Y) in adrenaline-type adrenal medullary cells, etc.. Both tissue-appropriate and tissue-inappropriate regulatory peptides are produced by endocrine tumours, with inappropriate peptides mostly produced by malignant tumours.

  15. Mathematical modeling of tornadoes and squall storms

    Directory of Open Access Journals (Sweden)

    Sergey A. Arsen’yev

    2011-04-01

    Full Text Available Recent advances in modeling of tornadoes and twisters consist of significant achievements in mathematical calculation of occurrence and evolution of a violent F5-class tornado on the Fujita scale, and four-dimensional mathematical modeling of a tornado with the fourth coordinate time multiplied by its characteristic velocity. Such a tornado can arise in a thunderstorm supercell filled with turbulent whirlwinds. A theory of the squall storms is proposed. The squall storm is modeled by running perturbation of the temperature inversion on the lower boundary of cloudiness. This perturbation is induced by the action of strong, hurricane winds in the upper and middle troposphere, and looks like a running solitary wave (soliton; which is developed also in a field of pressure and velocity of a wind. If a soliton of a squall storm gets into the thunderstorm supercell then this soliton is captured by supercell. It leads to additional pressure fall of air inside a storm supercell and stimulate amplification of wind velocity here. As a result, a cyclostrophic balance inside a storm supercell generates a tornado. Comparison of the radial distribution of wind velocity inside a tornado calculated by using the new formulas and equations with radar observations of the wind velocity inside Texas Tornado Dummit in 1995 and inside the 3 May 1999 Oklahoma City Tornado shows good correspondence.

  16. Electromagnetic pulses produced by expanding laser-produced Au plasma

    Directory of Open Access Journals (Sweden)

    De Marco Massimo

    2015-06-01

    Full Text Available The interaction of an intense laser pulse with a solid target produces large number of fast free electrons. This emission gives rise to two distinct sources of the electromagnetic pulse (EMP: the pulsed return current through the holder of the target and the outflow of electrons into the vacuum. A relation between the characteristics of laser-produced plasma, the target return current and the EMP emission are presented in the case of a massive Au target irradiated with the intensity of up to 3 × 1016 W/cm2. The emission of the EMP was recorded using a 12 cm diameter Moebius loop antennas, and the target return current was measured using a new type of inductive target probe (T-probe. The simultaneous use of the inductive target probe and the Moebius loop antenna represents a new useful way of diagnosing the laser–matter interaction, which was employed to distinguish between laser-generated ion sources driven by low and high contrast laser pulses.

  17. Method for producing a tube

    Science.gov (United States)

    Peterson, Kenneth A.; Rohde, Steven B.; Pfeifer, Kent B.; Turner, Timothy S.

    2007-01-02

    A method is described for producing tubular substrates having parallel spaced concentric rings of electrical conductors that can be used as the drift tube of an Ion Mobility Spectrometer (IMS). The invention comprises providing electrodes on the inside of a tube that are electrically connected to the outside of the tube through conductors that extend between adjacent plies of substrate that are combined to form the tube. Tubular substrates are formed from flexible polymeric printed wiring board materials, ceramic materials and material compositions of glass and ceramic, commonly known as Low Temperature Co-Fired Ceramic (LTCC). The adjacent plies are sealed together around the electrode.

  18. Producing biofuels using polyketide synthases

    Science.gov (United States)

    Katz, Leonard; Fortman, Jeffrey L; Keasling, Jay D

    2013-04-16

    The present invention provides for a non-naturally occurring polyketide synthase (PKS) capable of synthesizing a carboxylic acid or a lactone, and a composition such that a carboxylic acid or lactone is included. The carboxylic acid or lactone, or derivative thereof, is useful as a biofuel. The present invention also provides for a recombinant nucleic acid or vector that encodes such a PKS, and host cells which also have such a recombinant nucleic acid or vector. The present invention also provides for a method of producing such carboxylic acids or lactones using such a PKS.

  19. Study on forecast method of thunderstorm based on weather types and physical diagnostic analysis in eastern region of Northwest China%基于天气分型和物理量诊断西北地区东部雷暴预报方法研究

    Institute of Scientific and Technical Information of China (English)

    孔德兵; 汪结华; 尚可政; 叶伟; 赵文婧; 王式功; 杨流贵

    2016-01-01

    利用2008—2013年西北地区东部169个气象观测站的天气实况资料和NCEP/NCAR 1°×1°再分析资料计算的对流参数对西北地区东部雷暴日进行了天气分型,并应用分型统计的参数阈值对2013年西北地区东部雷暴日进行了试预报。结果表明:2008—2013年西北地区东部雷暴日集中出现在5—9月,占雷暴总日数的85.9%;雷暴日发生的天气形势可分为低涡型、低槽型、西北气流型和西南气流型4种。引入天气型强度指数,研究4种雷暴天气型的自动识别方法,通过天气分型检验表明,天气型自动识别方法可准确的识别雷暴发生的天气形势,且漏报较少。在天气型识别的基础上,进一步进行雷暴物理量诊断表明,消空效果明显。2008—2012年西北地区东部雷暴日回代预报的TS评分为54.1%,漏报雷暴日为4 d;2013年雷暴日试预报的TS评分为51.8%,漏报雷暴日为10 d;雷暴日回代预报与试预报的TS评分均超过气候概率,预报效果较理想,可为西北地区东部雷暴天气预报研究提供参考。%Based on the meteorological observations from 169 meteorological stations and the NCEP/NCAR (Na-tional Centers for Environmental Prediction/National Center for Atmospheric Research)reanalysis data with reso-lution of 1°×1°in the eastern region of Northwest China from 2008 to 2013,weather types of thunderstorm days were classified using calculated convective parameters,and the operational forecast of thunderstorm in 20 1 3 was carried out according to parameter thresholds of different weather types.The results show that thunderstorm days mostly occur from May to September and account for 85.9%of the total thunderstorm days during this study peri-od.There are four weather types of thunderstorm days,including the lower vortex type,the lower trough type,the northwesterly flow type,and the southwesterly flow type.The automatic identification method of

  20. Producing The New Regressive Left

    DEFF Research Database (Denmark)

    Crone, Christine

    to be a committed artist, and how that translates into supporting al-Assad’s rule in Syria; the Ramadan programme Harrir Aqlak’s attempt to relaunch an intellectual renaissance and to promote religious pluralism; and finally, al-Mayadeen’s cooperation with the pan-Latin American TV station TeleSur and its ambitions...... becomes clear from the analytical chapters is the emergence of the new cross-ideological alliance of The New Regressive Left. This emerging coalition between Shia Muslims, religious minorities, parts of the Arab Left, secular cultural producers, and the remnants of the political,strategic resistance...... coalition (Iran, Hizbollah, Syria), capitalises on a series of factors that bring them together in spite of their otherwise diverse worldviews and agendas. The New Regressive Left is united by resistance against the growing influence of Saudi Arabia in the religious, cultural, political, economic...

  1. Soybean biomass produced in Argentina

    DEFF Research Database (Denmark)

    Semino, Stella; Paul, Helena; Tomei, Julia

    Soybean biomass for biodiesel, produced in Argentina amongst other places, is considered by some to reduce greenhouse gas emissions and mitigate climate change when compared with fossil fuel. To ensure that the production of biofuels is ‘sustainable', EU institutions and national governments...... are currently designing certification schemes for the sustainable production of biomass. This paper questions the validity of proposed environmental standards, using the production of Argentine soybean as a case study. The production of soybean production is associated with profound environmental impacts...... generates emissions of N2O. The large quantity of substances, sprayed by terrestrial and aerial means, has negative impacts on biodiversity, water, soil, and human and animal health. The intensive production of soybeans also leads to social impacts, including loss of livelihoods and food sovereignty...

  2. ANTIPROTONS PRODUCED IN SUPERNOVA REMNANTS

    Energy Technology Data Exchange (ETDEWEB)

    Berezhko, E. G.; Ksenofontov, L. T., E-mail: ksenofon@ikfia.sbras.ru [Yu. G. Shafer Institute of Cosmophysical Research and Aeronomy, 31 Lenin Avenue, 677891 Yakutsk (Russian Federation)

    2014-08-20

    We present the energy spectrum of an antiproton cosmic ray (CR) component calculated on the basis of the nonlinear kinetic model of CR production in supernova remnants (SNRs). The model includes the reacceleration of antiprotons already existing in the interstellar medium as well as the creation of antiprotons in nuclear collisions of accelerated protons with gas nuclei and their subsequent acceleration by SNR shocks. It is shown that the production of antiprotons in SNRs produces a considerable effect in their resultant energy spectrum, making it essentially flatter above 10 GeV so that the spectrum at TeV energies increases by a factor of 5. The calculated antiproton spectrum is consistent with the PAMELA data, which correspond to energies below 100 GeV. As a consistency check, we have also calculated within the same model the energy spectra of secondary nuclei and show that the measured boron-to-carbon ratio is consistent with the significant SNR contribution.

  3. Leaf-produced floral signals.

    Science.gov (United States)

    Zeevaart, Jan A D

    2008-10-01

    Florigen is the hypothetical leaf-produced signal that induces floral initiation at the shoot apex. The nature of florigen has remained elusive for more than 70 years. But recent progress toward understanding the regulatory network for flowering in Arabidopsis has led to the suggestion that FLOWERING LOCUS T (FT) or its product is the mobile flower-inducing signal that moves from an induced leaf through the phloem to the shoot apex. In the past year, physical and chemical evidence has shown that it is FT protein, and not FT mRNA, that moves from induced leaves to the apical meristem. These results have established that FT is the main, if not the only, component of the universal florigen.

  4. Karakteristik Medan Listrik Atmosfer Kota Padang dan Hubungannya dengan Sambaran Petir Awan ke Tanah

    Directory of Open Access Journals (Sweden)

    Primas Emeraldi

    2017-03-01

    Full Text Available The possibility of using Electric Field Mill data as parameter of lightning warning sistem requires atmospheric electric field data comparisons with lightning detection sistems. Transient electric field from lightning detektor compare with continues atmospheric electric field during thunderstorm.Based on atmospheric electric field measurement in Padang during the period of January - August 2015 there were 219 times thunderstorm events. In the event of thunderstorm,there is one or two thunderstorm event per day with average thunderstorm duration 173.48 minute per thunderstorm. There is no relations between the number of cloud to ground lightning strikes with the duration of the thunderstorm. Thunderstorm with 634 minute duration produces 2 cloud to ground lightning strikes while thunderstorm with shorter duration for 114 minute produces 13 cloud to ground lightning strikes.

  5. Selection of phytotoxin producing rhizobacteria

    Directory of Open Access Journals (Sweden)

    Daniel D.C. Carvalho

    2011-09-01

    Full Text Available In order to select phytotoxin producing rhizobacteria to control weed plants, twenty five bacterial strains previously isolated from the rhizospheres of various plants were grown in a liquid medium and, after cell removal by centrifugation, the liquid phases were freeze-dried and the products were extracted with ethyl acetate/methanol. The extracts were concentrated to dryness under vacuum and dissolved in water and sucrose solution to be submitted to in vitro assays of lettuce (Lactuca sativa L. seed germination and wheat (Triticum aestivum L. coleoptile growth. Although most samples affected coleoptile growth, only those from four strains reduced lettuce seed germination. Two strains of Bacillus cereus, one strain of B. pumilus and one of Stenotrophoonas altophilia were the most promising microorganisms for producing phytotoxin and, consequently, for the development of new weed control products.Com o objetivo de selecionar rizobactérias produtoras de fitotoxinas para uso no controle de plantas daninhas, vinte e cinco isolados bacterianos previamente obtidos das rizosferas de diferentes plantas foram cultivados em meio líquido e, após remoção das células por centrifugação, as fases líquidas foram liofilizadas e os resíduos obtidos foram submetidos à extração com acetato de etila/metanol. Os extratos foram concentrados sob vácuo até secura e dissolvidos em água e solução de sacarose para serem submetidos a testes in vitro de germinação de sementes de alface (Lactuca sativa L. e de crescimento de coleóptilos de trigo (Triticum aestivum L.. Embora a maior parte das amostras tenha desfavorecido o crescimento dos coleóptilos de trigo, somente as provenientes de quatro isolados reduziram a germinação das sementes de alface. Dois isolados de Bacillus cereus, um isolado de B. pumilus e um de Stenotrophomonas maltophilia foram os microrganismos mais promissores para a produção de fitotoxinas, com possibilidade de uso no

  6. Yeast: A new oil producer?

    Directory of Open Access Journals (Sweden)

    Beopoulos Athanasios

    2012-01-01

    Full Text Available The increasing demand of plant oils or animal fat for biodiesel and specific lipid derivatives for the oleochemical field (such as lubricants, adhesives or plastics have created price imbalance in both the alimentary and energy field. Moreover, the lack of non-edible oil feedstock has given rise to concerns on land-use practices and on oil production strategies. Recently, much attention has been paid to the exploitation of microbial oils. Most of them present lipid profiles similar in type and composition to plants and could therefore have many advantages as are no competitive with food, have short process cycles and their cultivation is independent of climate factors. Among microorganisms, yeasts seem to be very promising as they can be easily genetically enhanced, are suitable for large-scale fermentation and are devoid of endotoxins. This review will focus on the recent understanding of yeasts lipid metabolism, the succeeding genetic engineering of the lipid pathways and the recent developments on fermentation techniques that pointed out yeasts as promising alternative producers for oil or plastic.

  7. Engineering microbes to produce biofuels.

    Science.gov (United States)

    Wackett, Lawrence P

    2011-06-01

    The current biofuels landscape is chaotic. It is controlled by the rules imposed by economic forces and driven by the necessity of finding new sources of energy, particularly motor fuels. The need is bringing forth great creativity in uncovering new candidate fuel molecules that can be made via metabolic engineering. These next generation fuels include long-chain alcohols, terpenoid hydrocarbons, and diesel-length alkanes. Renewable fuels contain carbon derived from carbon dioxide. The carbon dioxide is derived directly by a photosynthetic fuel-producing organism(s) or via intermediary biomass polymers that were previously derived from carbon dioxide. To use the latter economically, biomass depolymerization processes must improve and this is a very active area of research. There are competitive approaches with some groups using enzyme based methods and others using chemical catalysts. With the former, feedstock and end-product toxicity loom as major problems. Advances chiefly rest on the ability to manipulate biological systems. Computational and modular construction approaches are key. For example, novel metabolic networks have been constructed to make long-chain alcohols and hydrocarbons that have superior fuel properties over ethanol. A particularly exciting approach is to implement a direct utilization of solar energy to make a usable fuel. A number of approaches use the components of current biological systems, but re-engineer them for more direct, efficient production of fuels.

  8. Method for producing diene hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Tsaylingol' d, A.L.; Abayev, G.N.; Mikhaylov, R.K.; Stepanov, G.A.; Troitskiy, A.P.

    1980-04-28

    A method is claimed for producing diene hydrocarbons by oxidational dehydration of paraffin or olefin hydrocarbons in a fluidized bed of a concentrate with circulation of the latter between the zones of the reaction of regeneration with the help of circulation stand pipes. To increase the efectiveness of the process, it is proposed to circulate the concentrate between the zones of reaction and regeneration, sequentially disposed in a common apparatus with a difference in the concentration of the concentrate in the circulation stand pipes disposed in the same apparatus and the zone of the reaction equal to 20-700 kg/m/sup 3/. For example, the process of oxidational dehydration of butane through the proposed system is conducted in an apparatus with a diameter of 1,000 mm, a circulation stand pipe diameter of 500 mm, a linear gas speed in the reaction zone of 0.6 m/s, and in the circulation stand pipe of 0.15 m/s. The concentration of the concentrate in the dehydration zone is 640 kg/m/sup 3/ and in the stand pipe, 970 kg/m/sup 3/. The volumetric ratio of the n-C/sub 4/H/sub 10/:air, air:vapor vapor in the form of a condensate is 1:7.2:4.5:5.5. The output of the butadiene is: in the passed butane, 32.9% and in the broken down butane, 52.5%. The butane conversion is 62.6%. The losses of the concentrate with the contact gas and with the regeneration gases is 1/3 as much for the supplied butane, than in a known method. The method makes it possible to reduce the air expenditure by 60%, to reduce the concentrate losses by 2-3 times and to simplify the industrial system.

  9. Thunderstorm Forecast Study for Eglin AFB, FL

    Science.gov (United States)

    1993-03-01

    forecast model and the Brier skill scores (BSS) for this model compared to persistance (Pers) and climatology ( Climo ) for indicated upper- and lower-level...discriminant analysis forecast model and Brer skill scores (BSS) for this model compared to persistence (Pers) and climatology ( Climo ) for indicated upper...and lower-level winds and 3-hour time periods beginning with stated hour (Z). Eglin Range Eglin Main Wnd Hr BS BSS vs Climo BSS vs Pers BS BSS vs

  10. 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.

  11. A Study of Turbulence Near Thunderstorm Tops

    Science.gov (United States)

    1989-05-01

    a sheared environment. For both types of waves, the value of the local gra- dient Richardson number (Ri) is an indicator of the regions of the wave...flow pasta cylinder. The situation appears to be analogous to airflow over mountains since an air parcel experiences an upward and downward motion when

  12. MUSIC for localization of thunderstorm cells

    Energy Technology Data Exchange (ETDEWEB)

    Mosher, J.C.; Lewis, P.S. [Los Alamos National Lab., NM (United States); Rynne, T.M. [Scientific Applications and Research Associates, Inc., Huntington Beach, CA (United States)

    1993-12-31

    Lightning represents an event detectable optically, electrically, and acoustically, and several systems are already in place to monitor such activity. Unfortunately, such detection of lightning can occur too late, since operations need to be protected in advance of the first lightning strike. Additionally, the bolt itself can traverse several kilometers before striking the ground, leaving a large region of uncertainty as to the center of the storm and its possible strike regions. NASA Kennedy Space Center has in place an array of electric field mills that monitor the (effectively) DC electric field. Prior to the first lightning strike, the surface electric fields rise as the storm generator within a thundercloud begins charging. Extending methods we developed for an analogous source localization problem in mangnetoencephalography, we present Cramer-Rao lower bounds and MUSIC scans for fitting a point-charge source model to the electric field mill data. Such techniques can allow for the identification and localization of charge centers in cloud structures.

  13. Climate and Weather Analysis of Afghanistan Thunderstorms

    Science.gov (United States)

    2011-09-01

    in Iran, the Hindu Kush Mountains in AFG, the Pamir Mountains in Tajikistan, and the Himalayan Mountains in southwestern China and northern India...129,500 km2 of high plateaus and sandy deserts at an average elevation of 915 m. Within this plateau are the isolated arid salt flats of the

  14. Framework for Producing Ecological Nowcasts

    Science.gov (United States)

    Votava, P.; Nemani, R. R.; Michaelis, A.; Milesi, C.; Hashimoto, H.; Ichii, K.; Melton, F.

    2007-12-01

    TOPS is a data and modeling software system designed to seamlessly integrate data from satellite, aircraft and ground sensors, and weather/climate models with application models to quickly and reliably produce operational nowcasts and forecasts of ecological conditions. Through automation of the data retrieval, pre-processing, integration, and modeling steps, TOPS is able to reliably provide data on current and predicted ecosystem conditions, allowing TOPS data products to be used in an operational setting for a range of applications. The core of the system is located and maintained by the Ecocast group at NASA Ames Research Center. We have develop a layered approach where at the lowest level the system interacts with the numerous data providers such as the Distributed Active Archive Centers (DAAC), the National Center for Environmental Predictions (NCEP), the National Weather Service (NWS), NOAA, and others. This subsystem is fully autonomous, gathering data through periodic query to the requesting centers sometimes as often as every 15-minutes. Subsets of our input datasets are also available by subscriptions and are being pushed to us as they become available (Oregon State University direct broadcast feed is an example of such interaction). When the data are obtained, they are archived in the database and then further processed to fit the application needs. Due to significant differences in climate and satellite data processing, we have two separate subsystems to accomplish the task. On the climate side, we merge ground station data with model data and grid these to required resolution together with generation of basic statistics and QA/QC information. The satellite processing subsystem performs spatial data tiling and subsetting, as well as composition of data sets based on the QA/QC information supplied, in order to obtain the highest quality inputs. After the climate and satellite data are processed, they are inserted into a database. The model framework

  15. Mercury Wet Scavenging and Deposition Differences by Precipitation Type.

    Science.gov (United States)

    Kaulfus, Aaron S; Nair, Udaysankar; Holmes, Christopher D; Landing, William M

    2017-03-07

    We analyze the effect of precipitation type on mercury wet deposition using a new database of individual rain events spanning the contiguous United States. Measurements from the Mercury Deposition Network (MDN) containing single rainfall events were identified and classified into six precipitation types. Mercury concentrations in surface precipitation follow a power law of precipitation depth that is modulated by precipitation system morphology. After controlling for precipitation depth, the highest mercury deposition occurs in supercell thunderstorms, with decreasing deposition in disorganized thunderstorms, quasi-linear convective systems (QLCS), extratropical cyclones, light rain, and land-falling tropical cyclones. Convective morphologies (supercells, disorganized, and QLCS) enhance wet deposition by a factor of at least 1.6 relative to nonconvective morphologies. Mercury wet deposition also varies by geographic region and season. After controlling for other factors, we find that mercury wet deposition is greater over high-elevation sites, seasonally during summer, and in convective precipitation.

  16. 7 CFR 1207.305 - Producer.

    Science.gov (United States)

    2010-01-01

    ... Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE POTATO RESEARCH AND PROMOTION PLAN Potato Research and Promotion Plan Definitions § 1207.305 Producer. Producer means any person engaged...

  17. Microbially produced phytotoxins and plant disease management ...

    African Journals Online (AJOL)

    Microbially produced phytotoxins and plant disease management. ... African Journal of Biotechnology ... Pathogenic fungi and bacteria often damage their host (plants) tissues by producing toxic metabolites, which induced various symptoms ...

  18. Bacteriocin producers from traditional food products

    OpenAIRE

    Thonart P.; Destain J.; Tine E.; Ngom A.; Diop MB.; Dubois-Dauphin R.

    2007-01-01

    A total of 220 strains of LAB isolated from 32 samples of traditional fermented food from Senegal were screened for bacteriocin production. Two bacteriocin producers, Lactococcus lactis subsp. lactis and Enterococcus faecium, were identifi ed from 12 bacteriocin-producing isolates on the basis of phenotypic analyses and 16S rDNA sequence. Both bacteriocins produced by new isolates show antimicrobial activity against Listeria monocytogenes and Bacillus coagulans whereas only that produced by L...

  19. Complex Choices: Producers Risk Management Strategies

    OpenAIRE

    Pennings, Joost M.E.; Isengildina, Olga; Irwin, Scott H.; Good, Darrel L.; Garcia, Philip; Frank, Julieta; Kuiper, W. Erno

    2005-01-01

    Producers have a wide variety of risk management instruments available. How do producers make a choice of risk management instruments? Using the recently developed choice bracketing framework, we examine what risk management strategies producers use and identify the factors that drive their risk management decisions. Our results identify that producers use a wide variety of combinations of risk management instruments and that they bracket their choices into sets of alternative risk management...

  20. 7 CFR 1032.13 - Producer milk.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 9 2010-01-01 2009-01-01 true Producer milk. 1032.13 Section 1032.13 Agriculture... and Orders; Milk), DEPARTMENT OF AGRICULTURE MILK IN THE CENTRAL MARKETING AREA Order Regulating Handling Definitions § 1032.13 Producer milk. Producer milk means the skim milk (or the skim equivalent of...

  1. 7 CFR 1006.13 - Producer milk.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 9 2010-01-01 2009-01-01 true Producer milk. 1006.13 Section 1006.13 Agriculture... and Orders; Milk), DEPARTMENT OF AGRICULTURE MILK IN THE FLORIDA MARKETING AREA Order Regulating Handling Definitions § 1006.13 Producer milk. Producer milk means the skim milk (or the skim equivalent of...

  2. 7 CFR 1131.13 - Producer milk.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 9 2010-01-01 2009-01-01 true Producer milk. 1131.13 Section 1131.13 Agriculture... and Orders; Milk), DEPARTMENT OF AGRICULTURE MILK IN THE ARIZONA MARKETING AREA Order Regulating Handling Definitions § 1131.13 Producer milk. Producer milk means the skim milk (or the skim equivalent of...

  3. 7 CFR 1001.13 - Producer milk.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 9 2010-01-01 2009-01-01 true Producer milk. 1001.13 Section 1001.13 Agriculture... and Orders; Milk), DEPARTMENT OF AGRICULTURE MILK IN THE NORTHEAST MARKETING AREA Order Regulating Handling Definitions § 1001.13 Producer milk. Producer milk means the skim milk (or the skim equivalent of...

  4. 7 CFR 1126.13 - Producer milk.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 9 2010-01-01 2009-01-01 true Producer milk. 1126.13 Section 1126.13 Agriculture... and Orders; Milk), DEPARTMENT OF AGRICULTURE MILK IN THE SOUTHWEST MARKETING AREA Order Regulating Handling Definitions § 1126.13 Producer milk. Producer milk means the skim milk (or the skim equivalent of...

  5. 7 CFR 1033.13 - Producer milk.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 9 2010-01-01 2009-01-01 true Producer milk. 1033.13 Section 1033.13 Agriculture... and Orders; Milk), DEPARTMENT OF AGRICULTURE MILK IN THE MIDEAST MARKETING AREA Order Regulating Handling Definitions § 1033.13 Producer milk. Producer milk means the skim milk (or the skim equivalent of...

  6. 29 CFR 780.213 - Produce business.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Produce business. 780.213 Section 780.213 Labor Regulations... Specific Situations Hatchery Operations § 780.213 Produce business. In some instances, hatcheries also engage in the produce business as such and commingle with the culled eggs and chickens other eggs and...

  7. 7 CFR 1219.20 - Producer.

    Science.gov (United States)

    2010-01-01

    ... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE HASS AVOCADO PROMOTION, RESEARCH, AND INFORMATION Hass Avocado Promotion, Research, and Information Order Definitions § 1219.20 Producer. Producer means any person who is engaged in the business of producing Hass avocados in the United...

  8. Off shore produced water treatment with pertraction

    NARCIS (Netherlands)

    Klaassen, R.

    2004-01-01

    During the production of oil and gas also water is produced. This produced water contains dispersed and dissolved oil components. The impact of offshore emissions of produced water on the environment and the treatment of technologies for it are currently under discussion. Emission limits tend to bec

  9. 7 CFR 1218.16 - Producer.

    Science.gov (United States)

    2010-01-01

    ... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE BLUEBERRY PROMOTION, RESEARCH, AND INFORMATION ORDER Blueberry Promotion, Research, and Information Order Definitions § 1218.16 Producer... is engaged in the business of producing, or causing to be produced for any market, blueberries...

  10. Produced Water Reinjection--the Way Out

    Institute of Scientific and Technical Information of China (English)

    Xia Huilan

    1997-01-01

    @@ It is the best way to make comprehensive utilization of produced water, save water and protect environment by treating oily produced water so as to make it meet the quality criteria for the water reinjected into the reservoir. So far, more than 46 produced water treatment stations and 148 reinjection stations have been built at Shengli oilfields.

  11. Dynamics of the Ecological Agroalimentary Produce Market

    Directory of Open Access Journals (Sweden)

    Cornelia Petroman

    2011-10-01

    Full Text Available The market of ecological agroalimentary produce in Romania tends to have a positive evolution, identical with the world market, according to the specialists in the field. The market of ecological produce in Romania is being developed: from the point of view of its life cycle, it is steadily going to the growth period. Since the appearance period passed away, now there is the unsatisfied need of green produce: the first producers able to meet this need have appeared and they have started to meet the needs related to these produce.

  12. Inventory transparency for agricultural produce through IOT

    Science.gov (United States)

    Srinivasan, S. P.; Sorna Shanthi, D.; Anand, Aashish V.

    2017-06-01

    Re-structuring the practices of traditional inventory management is becoming more essential to optimize the supply chain transparency and accuracy of agricultural produce. A flexible and transparent inventory management system is becoming the need of any agricultural commodity. It was noticed that the major setback for the farmers who are the suppliers of the farm produce is due to poor supply chain integration. The recent advent technologies and IT explosion can bring up a greater impact in the process of storing, tracking, distributing and monitoring perishable agriculture produce of day to day life. The primary focus of this paper is to integrate IoT into inventory management and other inbound logistics management of agriculture produce. The unique features of agricultural produce like a prediction of supply, demand, the location of warehouses, distribution and tracking of inventory can be integrated through IoT. This paper proposes a conceptual framework for inventory management transparency involved in the supply chain of agriculture produce.

  13. Stable, fertile, high polyhydroxyalkanoate producing plants and methods of producing them

    Energy Technology Data Exchange (ETDEWEB)

    Bohmert-Tatarev, Karen; McAvoy, Susan; Peoples, Oliver P.; Snell, Kristi D.

    2015-08-04

    Transgenic plants that produce high levels of polyhydroxybutyrate and methods of producing them are provided. In a preferred embodiment the transgenic plants are produced using plastid transformation technologies and utilize genes which are codon optimized. Stably transformed plants able to produce greater than 10% dwt PHS in tissues are also provided.

  14. Bioavailability of isoflavones from soy products in equol producers and non-producers in Japanese women

    Directory of Open Access Journals (Sweden)

    Ayako Miura

    2016-12-01

    Conclusions: The results in this study suggest that bioavailability of isoflavones are different between equol producers and non-producers, because the 24 h urinary excretion of equol in the equol producers were significantly lower than those in the equol non-producers.

  15. Understanding producers' motives for adopting sustainable practices

    NARCIS (Netherlands)

    Trujillo-Barrera, Andres; Pennings, Joost M.E.; Hofenk, Dianne

    2016-01-01

    Understanding the motives and risk attitudes of producers to engage in sustainable practices is important for policy-makers who wish to increase the likelihood of adoption and improve the design of incentives. This article examines the underlying motives of producers to adopt sustainable

  16. 7 CFR 1030.13 - Producer milk.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 9 2010-01-01 2009-01-01 true Producer milk. 1030.13 Section 1030.13 Agriculture... and Orders; Milk), DEPARTMENT OF AGRICULTURE MILK IN THE UPPER MIDWEST MARKETING AREA Order Regulating Handling Definitions § 1030.13 Producer milk. Except as provided for in paragraph (e) of this section...

  17. 7 CFR 1005.13 - Producer milk.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 9 2010-01-01 2009-01-01 true Producer milk. 1005.13 Section 1005.13 Agriculture... and Orders; Milk), DEPARTMENT OF AGRICULTURE MILK IN THE APPALACHIAN MARKETING AREA Order Regulating Handling Definitions § 1005.13 Producer milk. Except as provided for in paragraph (e) of this section...

  18. 7 CFR 1007.13 - Producer milk.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 9 2010-01-01 2009-01-01 true Producer milk. 1007.13 Section 1007.13 Agriculture... and Orders; Milk), DEPARTMENT OF AGRICULTURE MILK IN THE SOUTHEAST MARKETING AREA Order Regulating Handling Definitions § 1007.13 Producer milk. Except as provided for in paragraph (e) of this section...

  19. 7 CFR 1124.13 - Producer milk.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 9 2010-01-01 2009-01-01 true Producer milk. 1124.13 Section 1124.13 Agriculture... and Orders; Milk), DEPARTMENT OF AGRICULTURE MILK IN THE PACIFIC NORTHWEST MARKETING AREA Order Regulating Handling Definitions § 1124.13 Producer milk. Except as provided for in paragraph (f) of this...

  20. Taxomyces andreanae : A Presumed Paclitaxel Producer Demystified?

    NARCIS (Netherlands)

    Staniek, Agata; Woerdenbag, Herman J.; Kayser, Oliver

    2009-01-01

    The 1990s brought an abundance of reports on paclitaxel-producing endophytes, initially heralded as a discovery having tremendous implications for cancer therapy. As the vision of large-scale fermentation tanks producing vast quantities of relatively inexpensive paclitaxel and novel taxanes has fade

  1. Automatic produce quality monitoring in Reefer containers

    NARCIS (Netherlands)

    Lukasse, L.J.S.; Sanders, M.G.; Kramer, de J.E.

    2003-01-01

    Current day perishable supply chains require intermediate points for manual produce quality inspection. Over the last decade international seatransport of fruit and vegetables in reefer containers has grown tremendously. Reefer containers may completely close the cold chain only if produce quality

  2. Music Teacher as Writer and Producer

    Science.gov (United States)

    Randles, Clint

    2012-01-01

    In this article I attempt to redefine the role of a music teacher as being more than a director, the more traditional term ascribed to this position. I do this by using descriptions of the role of "writer" and "producer" of student lives borrowed from music education philosophy, screenwriting, and professional music producers. This vision is…

  3. Exopolysaccharides produced by lactic acid bacteria

    NARCIS (Netherlands)

    Caggianiello, Graziano; Kleerebezem, Michiel; Spano, Giuseppe

    2016-01-01

    A wide range of lactic acid bacteria (LAB) is able to produce capsular or extracellular polysaccharides, with various chemical compositions and properties. Polysaccharides produced by LAB alter the rheological properties of the matrix in which they are dispersed, leading to typically viscous and

  4. 7 CFR 1206.16 - Producer.

    Science.gov (United States)

    2010-01-01

    ... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE MANGO PROMOTION, RESEARCH, AND INFORMATION Mango Promotion, Research, and Information Order Definitions § 1206.16 Producer. Producer means any person who is engaged in the production and sale of mangos in the United States and who owns,...

  5. 7 CFR 1206.8 - Foreign producer.

    Science.gov (United States)

    2010-01-01

    ... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE MANGO PROMOTION, RESEARCH, AND INFORMATION Mango Promotion, Research, and Information Order Definitions § 1206.8 Foreign producer. Foreign producer means any person: (1) Who is engaged in the production and sale of mangos outside of the...

  6. Particular applications of food irradiation fresh produce

    Science.gov (United States)

    Prakash, Anuradha

    2016-12-01

    On fresh fruits and vegetables, irradiation at low and medium dose levels can effectively reduce microbial counts which can enhance safety, inhibit sprouting to extend shelf-life, and eliminate or sterilize insect pests which can serve to facilitate trade between countries. At the dose levels used for these purposes, the impact on quality is negligible. Despite the fact that regulations in many countries allow the use of irradiation for fresh produce, the technology remains under-utilized, even in the light of an increase in produce related disease outbreaks and the economic benefits of extended shelf life and reduced food waste. Putative concerns about consumer acceptance particularly for produce that is labeled as irradiated have deterred many companies from using irradiation and retailers to carry irradiated produce. This section highlights the commercial use of irradiation for fresh produce, other than phytosanitary irradiation which is covered in supplementary sections.

  7. Factors affecting success of agricultural producers groups

    Directory of Open Access Journals (Sweden)

    Aleksandra Chlebicka

    2011-01-01

    Full Text Available Poor organisation of agricultural markets in Poland remains one of the biggest problems for agricultural sector. There are about 510 agricultural producer groups, but only 2% of Polish farmers selling for market are members. Knowledge on cooperation determinants and different aspects of producer groups performance is crucial to build references for policy makers and producer groups’ managers. The aim of the article was to discuss factors affecting success of producers groups understood as a level of members’ satisfaction. Data for 2006 and 2011 from 30 producers groups in fruit and vegetable sector were analysed using logit model. Three determinants occurred to be statistically important: scope of a group functions, informal cooperation with farmers before starting a formal cooperation and homogeneity of farms.

  8. Bacteriocin producers from traditional food products

    Directory of Open Access Journals (Sweden)

    Thonart P.

    2007-01-01

    Full Text Available A total of 220 strains of LAB isolated from 32 samples of traditional fermented food from Senegal were screened for bacteriocin production. Two bacteriocin producers, Lactococcus lactis subsp. lactis and Enterococcus faecium, were identified from 12 bacteriocin-producing isolates on the basis of phenotypic analyses and 16S rDNA sequence. Both bacteriocins produced by new isolates show antimicrobial activity against Listeria monocytogenes and Bacillus coagulans whereas only that produced by Lactococcus lactis has an activity against Bacillus cereus. Bacteriocin-producing Lactococcus lactis strains were found in a variety of traditional foods indicating a high potential of growth of this strain in variable ecological complex environment. Partial 16S rDNA of the two bacteriocin producers obtained in this study has been registered to Genbank databases under the accession number AY971748 for Lactococcus lactis subsp. lactis (named CWBI-B1410 and AY971749 for Enterococcus faecium (named CWBI-B1411. The new bacteriocin-producing Lactococcus lactis subsp. lactis strain has been selected for identification and application of the bacteriocin to food preservation.

  9. Biocorrosion produced by Thiobacillus-like microorganisms.

    Science.gov (United States)

    López, A I; Marín, I; Amils, R

    1994-01-01

    Biocorrosion can be produced by many different microorganisms through diverse mechanisms. The biocorrosion produced by acidophilic microorganisms of the genus Thiobacillus is based on the production of sulfuric acid and ferric ion from pyrites or related mineral structures, as a result of the chemolithotrophic metabolism of these microorganisms. The products of this aerobic respiration are also powerful oxidant elements, which can produce chemical oxidations of other metallic structures. The Tinto River, a very unusual extremophilic habitat (pH around 2, and high concentration of ferric ion), product of the growth of strict chemolithotrophic microorganisms, is discussed as a model case.

  10. Supercell convergence of charge-transfer energies in pentacene molecular crystals from constrained DFT

    CERN Document Server

    Turban, David H P; O'Regan, David D; Hine, Nicholas D M

    2016-01-01

    Singlet fission (SF) is a multi-exciton generation process that could be harnessed to improve the efficiency of photovoltaic devices. Experimentally, systems derived from the pentacene molecule have been shown to exhibit ultrafast SF with high yields. Charge-transfer (CT) configurations are likely to play an important role as intermediates in the SF process in these systems. In molecular crystals, electrostatic screening effects and band formation can be significant in lowering the energy of CT states, enhancing their potential to effectively participate in SF. In order to simulate these, it desirable to adopt a computational approach which is acceptably accurate, relatively inexpensive, which and scales well to larger systems, thus enabling the study of screening effects. We propose a novel, electrostatically-corrected constrained Density Functional Theory (cDFT) approach as a low-cost solution to the calculation of CT energies in molecular crystals such as pentacene. Here we consider an implementation in th...

  11. Coarse graining approach to First principles modeling of radiation cascade in large Fe super-cells

    Science.gov (United States)

    Odbadrakh, Khorgolkhuu; Nicholson, Don; Rusanu, Aurelian; Wang, Yang; Stoller, Roger; Zhang, Xiaoguang; Stocks, George

    2012-02-01

    First principles techniques employed to understand systems at an atomistic level are not practical for large systems consisting of millions of atoms. We present an efficient coarse graining approach to bridge the first principles calculations of local electronic properties to classical Molecular Dynamics (MD) simulations of large structures. Local atomic magnetic moments in crystalline Fe are perturbed by radiation generated defects. The effects are most pronounced near the defect core and decay with distance. We develop a coarse grained technique based on the Locally Self-consistent Multiple Scattering (LSMS) method that exploits the near-sightedness of the electron Green function. The atomic positions were determined by MD with an embedded atom force field. The local moments in the neighborhood of the defect cores are calculated with first-principles based on full local structure information. Atoms in the rest of the system are modeled by representative atoms with approximated properties. This work was supported by the Center for Defect Physics, an Energy Frontier Research Center funded by the US Department of Energy, Office of Science, Office of Basic Energy Sciences.

  12. Fluctuations and Anharmonicity in Lead Iodide Perovskites from Molecular Dynamics Supercell Simulationss

    KAUST Repository

    Carignano, Marcelo Andrés

    2017-09-05

    We present a systematic study based on first principles molecular dynamics simulations of lead iodide perovskites with three different cations, including methylammonium (MA), formamidinium (FA) and cesium. Using the high temperature perovskite structure as a reference, we investigate the instabilities that develop as the material is cooled down to 370 K. All three perovskites display anharmonicity in the motion of the iodine atoms, with the stronger effect observed for the MAPbI$_3$ and CsPbI$_3$. At high temperature, this behavior can be traced back to the reduced effective size of the Cs$^+$ and MA$^+$ cations. MAPbI$_3$ undergoes a spontaneous phase transition within our simulation model driven by the dipolar interaction between neighboring MA cations as the temperature is decreased from 450 K. The reverse transformation from tetragonal to cubic is also monitored through the large distribution of the octahedral tilting angles accompanied by an increase in the anharmonicity of the iodine atoms motion. Both MA and FA hybrid perovskites show a strong coupling between the molecular orientations and the local lattice deformations, suggesting mixed order-disorder/displacive characters of the high temperature phase transitions.

  13. [Metabolomics analysis of taxadiene producing yeasts].

    Science.gov (United States)

    Yan, Huifang; Ding, Mingzhu; Yuan, Yingjin

    2014-02-01

    In order to study the inherent difference among terpenes producing yeasts from the point of metabolomics, we selected taxadiene producing yeasts as the model system. The changes of cellular metabolites during fermentation log phase of artificial functional yeasts were determined using metabolomics methods. The results represented that compared to W303-1A as a blank control, the metabolites in glycolysis, tricarboxylic acid cycle (TCA) cycle and several amino acids were influenced. And due to the changes of metabolites, the growth of cells was inhibited to a certain extent. Among the metabolites identified, citric acid content in taxadiene producing yeasts changed the most, the decreasing amplitude reached 90% or more. Therefore, citric acid can be a marker metabolite for the future study of artificial functional yeasts. The metabolomics analysis of taxadiene producing yeasts can provide more information in further studies on optimization of terpenes production in heterologous chassis.

  14. Producing Knowledge to Reduce Rhetorical Distance

    DEFF Research Database (Denmark)

    Kampf, Constance

    Producing Knowledge to Reduce Rhetorical Distance: Extending Identity and Engaging Mainstream Ideology via the Web Constance Kampf, Department of Research Knowledge Communication, Aarhus School of Business, Denmark McLuhan describes technologies as extensions -the wheel being an extension...

  15. An anaerobic mitochondrion that produces hydrogen

    NARCIS (Netherlands)

    Boxma, Brigitte; Graaf, Rob M. de; Staay, Georg W.M. van der; Alen, Theo A. van; Ricard, Guenola; Gabaldón, Toni; Hoek, Angela H.A.M. van; Moon-van der Staay, Seung Yeo; Koopman, Werner J.H.; Hellemond, Jaap J. van; Tielens, Aloysius G.M.; Friedrich, Thorsten; Veenhuis, Marten; Huynen, Martijn A.; Hackstein, Johannes H.P.

    2005-01-01

    Hydrogenosomes are organelles that produce ATP and hydrogen, and are found in various unrelated eukaryotes, such as anaerobic flagellates, chytridiomycete fungi and ciliates. Although all of these organelles generate hydrogen, the hydrogenosomes from these organisms are structurally and metabolicall

  16. Quest II produce quality research overview

    NARCIS (Netherlands)

    Lukasse, L.J.S.; Harkema, H.; Otma, E.C.; Paillart, M.J.M.

    2013-01-01

    The Quest II control algorithm (patent pending), developed by Wageningen UR Food & Biobased Research together with Maersk Line and Carrier Transicold, reduces the energy consumption of reefer containers by approx. 65% without impairing produce quality.

  17. Factors affecting effective performance of rural producers ...

    African Journals Online (AJOL)

    Mo

    Factors affecting effective performance of rural producers' organizations in the ... Linkages are vital for effective achievement of purposes and most RPOs (80%), had established them ..... Success: Learning from Instructive Experiences in Ru-.

  18. Do bacteria, not fish, produce 'fish kairomone'?

    NARCIS (Netherlands)

    Ringelberg, J.; Van Gool, E.

    1998-01-01

    Fish-associated chemicals enhance phototactic downward swimming in Daphnia. If perch were treated with the antibiotic ampicillin, this enhancement was significantly decreased. Therefore, not fish, but bacteria associated with fish, seem to produce this kairomone. [KEYWORDS: Diel vertical migration;

  19. Potential biosurfactant producing endophytic and epiphytic fungi ...

    African Journals Online (AJOL)

    João Marcelo Lima

    L., macrophytes collected from oil-contaminated waters, were studied to assess their potential for producing .... Surface tension is a common metric and direct method for monitoring the production ..... Isolation and purification of a new enamide ...

  20. 9 CFR 114.16 - Producing subsidiaries.

    Science.gov (United States)

    2010-01-01

    ... AGRICULTURE VIRUSES, SERUMS, TOXINS, AND ANALOGOUS PRODUCTS; ORGANISMS AND VECTORS PRODUCTION REQUIREMENTS FOR BIOLOGICAL PRODUCTS § 114.16 Producing subsidiaries. A serial or subserial of a biological product may...

  1. 7 CFR 1280.117 - Producer information.

    Science.gov (United States)

    2010-01-01

    ... AGREEMENTS AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE LAMB PROMOTION, RESEARCH, AND INFORMATION ORDER Lamb Promotion, Research, and Information Order Definitions § 1280.117 Producer information... information relating to production or marketing efficiencies, development of new markets, program activities...

  2. 7 CFR 926.7 - Producer.

    Science.gov (United States)

    2010-01-01

    ... of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE DATA COLLECTION, REPORTING AND RECORDKEEPING REQUIREMENTS APPLICABLE TO CRANBERRIES NOT SUBJECT TO THE CRANBERRY MARKETING ORDER § 926.7 Producer....

  3. Methods and systems for producing syngas

    Energy Technology Data Exchange (ETDEWEB)

    Hawkes, Grant L; O& #x27; Brien, James E; Stoots, Carl M; Herring, J. Stephen; McKellar, Michael G; Wood, Richard A; Carrington, Robert A; Boardman, Richard D

    2013-02-05

    Methods and systems are provided for producing syngas utilizing heat from thermochemical conversion of a carbonaceous fuel to support decomposition of at least one of water and carbon dioxide using one or more solid-oxide electrolysis cells. Simultaneous decomposition of carbon dioxide and water or steam by one or more solid-oxide electrolysis cells may be employed to produce hydrogen and carbon monoxide. A portion of oxygen produced from at least one of water and carbon dioxide using one or more solid-oxide electrolysis cells is fed at a controlled flow rate in a gasifier or combustor to oxidize the carbonaceous fuel to control the carbon dioxide to carbon monoxide ratio produced.

  4. An anaerobic mitochondrion that produces hydrogen

    NARCIS (Netherlands)

    Boxma, Brigitte; Graaf, Rob M. de; Staay, Georg W.M. van der; Alen, Theo A. van; Ricard, Guenola; Gabaldón, Toni; Hoek, Angela H.A.M. van; Moon-van der Staay, Seung Yeo; Koopman, Werner J.H.; Hellemond, Jaap J. van; Tielens, Aloysius G.M.; Friedrich, Thorsten; Veenhuis, Marten; Huynen, Martijn A.; Hackstein, Johannes H.P.

    2005-01-01

    Hydrogenosomes are organelles that produce ATP and hydrogen, and are found in various unrelated eukaryotes, such as anaerobic flagellates, chytridiomycete fungi and ciliates. Although all of these organelles generate hydrogen, the hydrogenosomes from these organisms are structurally and metabolicall

  5. Produced Water Management and Beneficial Use

    Energy Technology Data Exchange (ETDEWEB)

    Terry Brown; Carol Frost; Thomas Hayes; Leo Heath; Drew Johnson; David Lopez; Demian Saffer; Michael Urynowicz; John Wheaton; Mark Zoback

    2007-10-31

    Large quantities of water are associated with the production of coalbed methane (CBM) in the Powder River Basin (PRB) of Wyoming. The chemistry of co-produced water often makes it unsuitable for subsequent uses such as irrigated agriculture. However, co-produced waters have substantial potential for a variety of beneficial uses. Achieving this potential requires the development of appropriate water management strategies. There are several unique characteristics of co-produced water that make development of such management strategies a challenge. The production of CBM water follows an inverse pattern compared to traditional wells. CBM wells need to maintain low reservoir pressures to promote gas production. This need renders the reinjection of co-produced waters counterproductive. The unique water chemistry of co-produced water can reduce soil permeability, making surface disposal difficult. Unlike traditional petroleum operations where co-produced water is an undesirable by-product, co-produced water in the PRB often is potable, making it a highly valued resource in arid western states. This research project developed and evaluated a number of water management options potentially available to CBM operators. These options, which focus on cost-effective and environmentally-sound practices, fall into five topic areas: Minimization of Produced Water, Surface Disposal, Beneficial Use, Disposal by Injection and Water Treatment. The research project was managed by the Colorado Energy Research Institute (CERI) at the Colorado School of Mines (CSM) and involved personnel located at CERI, CSM, Stanford University, Pennsylvania State University, the University of Wyoming, the Argonne National Laboratory, the Gas Technology Institute, the Montana Bureau of Mining and Geology and PVES Inc., a private firm.

  6. Biologically produced sulfur particles and polysulfide ions

    OpenAIRE

    Kleinjan, W. E.

    2005-01-01

    This thesis deals with the effects of particles of biologically produced sulfur (or 'biosulfur') on a biotechnological process for the removal of hydrogen sulfide from gas streams. Particular emphasis is given to the role of polysulfide ions in such a process. These polysulfide ions are formed from reaction of sulfide with biologically produced sulfur. The basic concepts of this H 2 S removal process were developed at the department of Environmental Technology of Wageningen University and the...

  7. Producing oil wells; A steep downhill road

    Energy Technology Data Exchange (ETDEWEB)

    1990-02-01

    This paper discusses the effects of the drilling collapse of the past few years. Even with improved and relatively stable pricing, the severely impeded drilling climate-coupled with the continued decline of marginal wells-has caused a drop of 3.2{percent} in the total number of producing oil wells. Based on an annual survey of state and regional petroleum agencies, World Oil estimates that 603,365 oil wells are currently producing in the United States.

  8. Use of aflatoxin-producing ability medium to distinguish aflatoxin-producing strains of Aspergillus flavus.

    OpenAIRE

    1981-01-01

    Aflatoxin-producing ability medium was tested for its ability to distinguish aflatoxin-positive from aflatoxin-negative strains of Aspergillus flavus in naturally occurring populations from corn at harvest. All of the aflatoxin-positive strains and some of the aflatoxin-negative strains produced aflatoxins when cultured on cracked corn. Although the data indicate that aflatoxin-producing ability medium is not entirely reliable in distinguishing potential aflatoxin-producing strains of A. flav...

  9. Wintertime Emissions from Produced Water Ponds

    Science.gov (United States)

    Evans, J.; Lyman, S.; Mansfield, M. L.

    2013-12-01

    Every year oil and gas drilling in the U.S. generates billions of barrels of produced water (water brought to the surface during oil or gas production). Efficiently disposing of produced water presents a constant financial challenge for producers. The most noticeable disposal method in eastern Utah's Uintah Basin is the use of evaporation ponds. There are 427 acres of produced water ponds in the Uintah Basin, and these were used to evaporate more than 5 million barrels of produced water in 2012, 6% of all produced water in the Basin. Ozone concentrations exceeding EPA standards have been observed in the Uintah Basin during winter inversion conditions, with daily maximum 8 hour average concentrations at some research sites exceeding 150 parts per billion. Produced water contains ozone-forming volatile organic compounds (VOC) which escape into the atmosphere as the water is evaporated, potentially contributing to air quality problems. No peer-reviewed study of VOC emissions from produced water ponds has been reported, and filling this gap is essential for the development of accurate emissions inventories for the Uintah Basin and other air sheds with oil and gas production. Methane, carbon dioxide, and VOC emissions were measured at three separate pond facilities in the Uintah Basin in February and March of 2013 using a dynamic flux chamber. Pond emissions vary with meteorological conditions, so measurements of VOC emissions were collected during winter to obtain data relevant to periods of high ozone production. Much of the pond area at evaporation facilities was frozen during the study period, but areas that actively received water from trucks remained unfrozen. These areas accounted for 99.2% of total emissions but only 9.5% of the total pond area on average. Ice and snow on frozen ponds served as a cap, prohibiting VOC from being emitted into the atmosphere. Emissions of benzene, toluene, and other aromatic VOCs averaged over 150 mg m-2 h-1 from unfrozen pond

  10. ANAEROBIC BIOLOGICAL TREATMENT OF PRODUCED WATER

    Energy Technology Data Exchange (ETDEWEB)

    John R. Gallagher

    2001-07-31

    During the production of oil and gas, large amounts of water are brought to the surface and must be disposed of in an environmentally sensitive manner. This is an especially difficult problem in offshore production facilities where space is a major constraint. The chief regulatory criterion for produced water is oil and grease. Most facilities have little trouble meeting this criterion using conventional oil-water separation technologies. However, some operations have significant amounts of naphthenic acids in the water that behave as oil and grease but are not well removed by conventional technologies. Aerobic biological treatment of naphthenic acids in simulated-produced water has been demonstrated by others; however, the system was easily overloaded by the large amounts of low-molecular-weight organic acids often found in produced waters. The objective of this research was to determine the ability of an anaerobic biological system to treat these organic acids in a simulated produced water and to examine the potential for biodegradation of the naphthenic acids in the anaerobic environment. A small fixed-film anaerobic biological reactor was constructed and adapted to treat a simulated produced water. The bioreactor was tubular, with a low-density porous glass packing material. The inocula to the reactor was sediment from a produced-water holding pond from a municipal anaerobic digester and two salt-loving methanogenic bacteria. During start-up, the feed to the reactor contained glucose as well as typical produced-water components. When glucose was used, rapid gas production was observed. However, when glucose was eliminated and the major organic component was acetate, little gas was generated. Methane production from acetate may have been inhibited by the high salt concentrations, by sulfide, or because of the lack, despite seeding, of microbes capable of converting acetate to methane. Toluene, a minor component of the produced water (0.1 g/L) was removed in the

  11. Zirconium alloys produced by recycling zircaloy tunings

    Energy Technology Data Exchange (ETDEWEB)

    Gamba, N.S. [Instituto de Investigaciones en Catálisis y Petroquímica, INCAPE (FIQ, UNL–CONICET), Santiago del Estero 2829, 3000 Santa Fe (Argentina); Carbajal-Ramos, I.A. [Centro Atómico Bariloche, CNEA e Instituto Balseiro, Universidad Nacional de Cuyo, Av. Bustillo 9500, 8400 Bariloche (Argentina); Ulla, M.A.; Pierini, B.T. [Instituto de Investigaciones en Catálisis y Petroquímica, INCAPE (FIQ, UNL–CONICET), Santiago del Estero 2829, 3000 Santa Fe (Argentina); Gennari, F.C., E-mail: gennari@cab.cnea.gov.ar [Centro Atómico Bariloche, CNEA e Instituto Balseiro, Universidad Nacional de Cuyo, Av. Bustillo 9500, 8400 Bariloche (Argentina)

    2013-11-25

    Highlights: •Zr–Ti alloys were successfully produced by two-step procedure. •Zircaloy tunings were used as a valuable source of Zr. •Zircaloy tunings and Ti powders was milled under hydrogen to produce hydride powders. •Hydride powders were decomposed by heating at 900 °C to synthesize the Zr-based alloy. •The procedure could be extended to the production of other Zr-based alloys. -- Abstract: Zircaloy chips were recycled to successfully produce Zr–Ti alloys with bcc structure and different compositions. The procedure developed involves two steps. First, the reactive mechanical alloying (RMA) of the zircaloy tunings and Ti powders was performed to produce metal hydride powders, with a high refinement of the microstructure and a Zr–Ti homogeneous composition. Second, the metal hydride powders were thermally decomposed by heating up to 900 °C to synthesize the Zr-based alloy with a selected composition. The change in the nature of the powders from ductile to brittle during milling avoids both cold working phenomena between the metals and the use of a control agent. A minimum milling time is necessary to produce the solid solution with the selected composition. The microstructure and structure of the final alloys obtained was studied. The present procedure could be extended to the production of Zr-based alloys with the addition of other metals different from Ti.

  12. Producer-level benefits of sustainability certification.

    Science.gov (United States)

    Blackman, Allen; Rivera, Jorge

    2011-12-01

    Initiatives certifying that producers of goods and services adhere to defined environmental and social-welfare production standards are increasingly popular. According to proponents, these initiatives create financial incentives for producers to improve their environmental, social, and economic performance. We reviewed the evidence on whether these initiatives have such benefits. We identified peer-reviewed, ex post, producer-level studies in economic sectors in which certification is particularly prevalent (bananas, coffee, fish products, forest products, and tourism operations), classified these studies on the basis of whether their design and methods likely generated credible results, summarized findings from the studies with credible results, and considered how these findings might guide future research. We found 46 relevant studies, most of which focused on coffee and forest products and examined fair-trade and Forest Stewardship Council certification. The methods used in 11 studies likely generated credible results. Of these 11 studies, nine examined the economic effects and two the environmental effects of certification. The results of four of the 11 studies, all of which examined economic effects, showed that certification has producer-level benefits. Hence, the evidence to support the hypothesis that certification benefits the environment or producers is limited. More evidence could be generated by incorporating rigorous, independent evaluation into the design and implementation of projects promoting certification.

  13. Heidrun Testing Produced Water Reinjection (Pwri)

    Energy Technology Data Exchange (ETDEWEB)

    Paltiel, Sten [Statoil, Stavanger (Norway)

    2001-07-01

    On the Heidrun platform in the Norwegian Sea, Statoil is carrying out tests to determine the feasibility of re-injecting produced water into the reservoir. There are two main incentives for the implementation of PWRI: - Environmental gains through reduced discharge to sea, - Provides a source of low sulphate water, which is positive for the reservoir. The production wells on the field need pressure support, and produced water is an alternative to the sea water that is currently used for this purpose. The Heidrun reservoir has a great potential for producing scale due to the high content of barium sulphate. Experience so far shows that if scaling goes unchecked, a large portion of the oil will be non-recoverable. Well treatments also create separation problems when back flowing. This means that maintaining the 40 mg/l limit is a challenge. (author)

  14. Components and Treatments of Oilfield Produced Water

    Directory of Open Access Journals (Sweden)

    Essam Abdul-Jalil Saeed

    2010-01-01

    Full Text Available In this study, a review of variety of processes that are used in the treatment produced water prior to reuse or to responsible disposal are presented with their environmental issues and economical benefits. Samples of produced water from five locations in Rumaila oilfield/in south of Iraq were taken and analyzed for their contents of brine, some heavy metals, total suspended solids and oil and grease. Moreover, two samples of water were treated using reverse osmosis technique which showed its ability to treat such contaminated water. The results showed that the environmental impact of produced water arises from its chemical composition; i.e., its salt content, its heavy metals, and hydrocarbon contents.

  15. Producing Hydrogen by Plasma Pyrolysis of Methane

    Science.gov (United States)

    Atwater, James; Akse, James; Wheeler, Richard

    2010-01-01

    Plasma pyrolysis of methane has been investigated for utility as a process for producing hydrogen. This process was conceived as a means of recovering hydrogen from methane produced as a byproduct of operation of a life-support system aboard a spacecraft. On Earth, this process, when fully developed, could be a means of producing hydrogen (for use as a fuel) from methane in natural gas. The most closely related prior competing process - catalytic pyrolysis of methane - has several disadvantages: a) The reactor used in the process is highly susceptible to fouling and deactivation of the catalyst by carbon deposits, necessitating frequent regeneration or replacement of the catalyst. b) The reactor is highly susceptible to plugging by deposition of carbon within fixed beds, with consequent channeling of flow, high pressure drops, and severe limitations on mass transfer, all contributing to reductions in reactor efficiency. c) Reaction rates are intrinsically low. d) The energy demand of the process is high.

  16. Global Spread of Carbapenemase-producing Enterobacteriaceae

    Science.gov (United States)

    Naas, Thierry; Poirel, Laurent

    2011-01-01

    Carbapenemases increasingly have been reported in Enterobacteriaceae in the past 10 years. Klebsiella pneumoniae carbapenemases have been reported in the United States and then worldwide, with a marked endemicity at least in the United States and Greece. Metallo-enzymes (Verona integron–encoded metallo-β-lactamase, IMP) also have been reported worldwide, with a higher prevalence in southern Europe and Asia. Carbapenemases of the oxacillinase-48 type have been identified mostly in Mediterranean and European countries and in India. Recent identification of New Delhi metallo-β-lactamase-1 producers, originally in the United Kingdom, India, and Pakistan and now worldwide, is worrisome. Detection of infected patients and carriers with carbapenemase producers is necessary for prevention of their spread. Identification of the carbapenemase genes relies mostly on molecular techniques, whereas detection of carriers is possible by using screening culture media. This strategy may help prevent development of nosocomial outbreaks caused by carbapenemase producers, particularly K. pneumoniae. PMID:22000347

  17. Characterization of Soluble Organics in Produced Water

    Energy Technology Data Exchange (ETDEWEB)

    Bostick, D.T.

    2002-01-16

    Soluble organics in produced water and refinery effluents represent treatment problems for the petroleum industry. Neither the chemistry involved in the production of soluble organics nor the impact of these chemicals on total effluent toxicity is well understood. The U.S. Department of Energy provides funding for Oak Ridge National Laboratory (ORNL) to support a collaborative project with Shell, Chevron, Phillips, and Statoil entitled ''Petroleum and Environmental Research Forum project (PERF 9844: Manage Water-Soluble Organics in Produced Water''). The goal of this project, which involves characterization and evaluation of these water-soluble compounds, is aimed at reducing the future production of such contaminants. To determine the effect that various drilling conditions might have on water-soluble organics (WSO) content in produced water, a simulated brine water containing the principal inorganic components normally found in Gulf of Mexico (GOM) brine sources was prepared. The GOM simulant was then contacted with as-received crude oil from a deep well site to study the effects of water cut, produced-water pH, salinity, pressure, temperature, and crude oil sources on the type and content of the WSO in produced water. The identities of individual semivolatile organic compounds (SVOCs) were determined in all as-received crude and actual produced water samples using standard USEPA Method (8270C) protocol. These analyses were supplemented with the more general measurements of total petroleum hydrocarbon (TPH) content in the gas (C{sub 6}-C{sub 10}), diesel (C{sub 10}-C{sub 20}), and oil (C{sub 20}-C{sub 28}) carbon ranges as determined by both gas chromatographic (GC) and infrared (IR) analyses. An open liquid chromatographic procedure was also used to differentiate the saturated hydrocarbon, aromatic hydrocarbon, and polar components within the extractable TPH. Inorganic constituents in the produced water were analyzed by ion

  18. User community vs. producer innovation development efficiency

    DEFF Research Database (Denmark)

    Hienerth, Christoph; von Hippel, Eric; Jensen, Morten Berg

    2014-01-01

    In this paper we report upon a first empirical exploration of the relative efficiency of innovation development by product users vs. product producers. In a study of over 50 years of product innovation in the whitewater kayaking field, we find users in aggregate were approximately 3× more efficient...... at developing important kayaking product innovations than were producers in aggregate. We speculate that this result is driven by what we term “efficiencies of scope” in problem-solving. These can favor an aggregation of many user innovators, each spending a little, over fewer producer innovators benefitting...... from higher economies of scale in product development. We also note that the present study explores only one initial point on what is likely to be a complex efficiency landscape....

  19. Chryseobacterium indologenes, novel mannanase-producing bacteria

    Directory of Open Access Journals (Sweden)

    Surachai Rattanasuk

    2009-10-01

    Full Text Available Mannanase is a mannan degrading enzyme which is produced by microorganisms, including bacteria. This enzyme can be used in many industrial processes as well as for improving the quality of animal feeds. The aim of the present study was toscreen and characterize the mannanase-producing bacteria. Two genera of bacteria were isolated from Thai soil samples,fermented coconut, and fertilizer. Screening was carried out on agar plates containing mannan stained with iodine solution.The bacteria were identified by partial 16S rRNA gene sequence, biochemical test and morphology, respectively. The mannanase activity was determined by zymogram and DNS method. Two strains of bacteria with mannanase activity were identified as Bacillus and Chryseobacterium. This is the first report of mannanase-producing Chryseobacterium.

  20. Salmonella in beef and produce from honduras.

    Science.gov (United States)

    Maradiaga, Martha; Miller, Mark F; Thompson, Leslie; Pond, Ansen; Gragg, Sara E; Echeverry, Alejandro; Garcia, Lyda G; Loneragan, Guy H; Brashears, Mindy M

    2015-03-01

    Salmonella continues to cause a considerable number of foodborne illnesses worldwide. The sources of outbreaks include contaminated meat and produce. The purpose of this study was to establish an initial investigation of the burden of Salmonella in produce and beef from Honduras by sampling retail markets and abattoirs. Retail produce samples (cantaloupes, cilantro, cucumbers, leafy greens, peppers, and tomatoes; n = 573) were purchased in three major cities of Honduras, and retail whole-muscle beef (n = 555) samples were also purchased in four major cities. Additionally, both hide and beef carcass (n = 141) samples were collected from two Honduran abattoirs. Whole-muscle beef samples were obtained using a sponge hydrated with buffered peptone water, and 10 ml of the buffered peptone water rinsate of each produce sample was collected with a dry sponge and placed in a bag to be transported back to the United States. Salmonella was detected using a commercially available, closeplatform PCR system, and positive samples were subjected to culture on selective media to obtain isolates. Overall, the prevalence of Salmonella-positive samples, based on PCR detection in Honduras (n = 555) retail beef was 10.1% (95% confidence interval = 7.8, 12.9), whereas 7.8% (n = 141) of beef carcass and hides samples were positive in both beef plants. The overall Salmonella prevalence for all produce samples (n = 573) collected was 2.1% (95% confidence interval = 1.2, 3.6). The most common serotypes identified in Honduras were Salmonella Typhimurium followed by Derby. These results provide an indication of Salmonella contamination of beef and produce in Honduras. Developing a Salmonella baseline for Latin America through an initial investigation like the one presented here contributes to a broader global understanding of the potential exposure through food, thus providing insight into the needs for control strategies.

  1. Neutrons produced by muons at 25 mwe

    Science.gov (United States)

    Dragić, A.; Aničin, I.; Banjanac, R.; Udovičić, V.; Joković, D.; Maletić, D.; Savić, M.; Veselinović, N.; Puzović, J.

    2013-02-01

    The flux of fast neutrons produced by CR muons in lead at the depth of 25 mwe is measured. Lead is a common shielding material and neutrons produced in it in muon interactions are unavoidable background component, even in sensitive deep underground experiments. A low background gamma spectrometer, equipped with high purity Ge detector in coincidence with muon detector is used for this purpose. Neutrons are identified by the structure at 692 KeV in the spectrum of delayed coincidences, caused by the neutron inelastic scattering on Ge-72 isotope. Preliminary result for the fast neutron rate is 3.1(5) × 10--4n/cm2 · s.

  2. Exceptional Antibodies Produced by Successive Immunizations.

    Directory of Open Access Journals (Sweden)

    Patricia J Gearhart

    2015-12-01

    Full Text Available Antibodies stand between us and pathogens. Viruses mutate quickly to avoid detection, and antibodies mutate at similar rates to hunt them down. This death spiral is fueled by specialized proteins and error-prone polymerases that change DNA sequences. Here, we explore how B lymphocytes stay in the race by expressing activation-induced deaminase, which unleashes a tsunami of mutations in the immunoglobulin loci. This produces random DNA substitutions, followed by selection for the highest affinity antibodies. We may be able to manipulate the process to produce better antibodies by expanding the repertoire of specific B cells through successive vaccinations.

  3. Methods for producing silicon carbide fibers

    Energy Technology Data Exchange (ETDEWEB)

    Garnier, John E.; Griffith, George W.

    2016-03-01

    Methods of producing silicon carbide fibers. The method comprises reacting a continuous carbon fiber material and a silicon-containing gas in a reaction chamber at a temperature ranging from approximately 1500.degree. C. to approximately 2000.degree. C. A partial pressure of oxygen in the reaction chamber is maintained at less than approximately 1.01.times.10.sup.2 Pascal to produce continuous alpha silicon carbide fibers. Continuous alpha silicon carbide fibers and articles formed from the continuous alpha silicon carbide fibers are also disclosed.

  4. Alkaloids produced by endophytic fungi: a review.

    Science.gov (United States)

    Zhang, Yanyan; Han, Ting; Ming, Qianliang; Wu, Lingshang; Rahman, Khalid; Qin, Luping

    2012-07-01

    In recent years, a number of alkaloids have been discovered from endophytic fungi in plants, which exhibited excellent biological properties such as antimicrobial, insecticidal, cytotoxic, and anticancer activities. This review mainly deals with the research progress on endophytic fungi for producing bioactive alkaloids such as quinoline and isoquinoline, amines and amides, indole derivatives, pyridines, and quinazolines. The biological activities and action mechanisms of these alkaloids from endophytic fungi are also introduced. Furthermore, the relationships between alkaloid-producing endophytes and their host plants, as well as their potential applications in the future are discussed.

  5. Methods for producing reinforced carbon nanotubes

    Science.gov (United States)

    Ren, Zhifen; Wen, Jian Guo; Lao, Jing Y.; Li, Wenzhi

    2008-10-28

    Methods for producing reinforced carbon nanotubes having a plurality of microparticulate carbide or oxide materials formed substantially on the surface of such reinforced carbon nanotubes composite materials are disclosed. In particular, the present invention provides reinforced carbon nanotubes (CNTs) having a plurality of boron carbide nanolumps formed substantially on a surface of the reinforced CNTs that provide a reinforcing effect on CNTs, enabling their use as effective reinforcing fillers for matrix materials to give high-strength composites. The present invention also provides methods for producing such carbide reinforced CNTs.

  6. Multi-scale evolution of a derecho-producing MCS

    Science.gov (United States)

    Bernardet, Ligia Ribeiro

    1997-12-01

    important branch of the downdraft has an 'up-down' trajectory. Parcels start close to the ground, are lifted up by a strong pressure gradient force, and become colder than their surroundings as they ascend in a stable environment. Then, as they go through the precipitation shaft, they sink due to negative buoyancy enhanced by condensate loading. The upward pressure gradient force is partially related to mid-level rotation in the storm, which has characteristics of a high-precipitation supercell.

  7. Earth's Most Important Producers: Meet the Phytoplankton!

    Science.gov (United States)

    Marrero, Meghan E.; Stevens, Nicole

    2011-01-01

    The ocean is home to some of Earth's most important producers. Single-celled organisms in the ocean are responsible for more than half of Earth's productivity, as well as most of its oxygen. Phytoplankton are single-celled, plantlike organisms. That is, they have chloroplasts and perform photosynthesis, but are not true plants, which are typically…

  8. Climate forecasts for corn producer decision making

    Science.gov (United States)

    Corn is the most widely grown crop in the Americas, with annual production in the United States of approximately 332 million metric tons. Improved climate forecasts, together with climate-related decision tools for corn producers based on these improved forecasts, could substantially reduce uncertai...

  9. Urban Stories : Producing news for urban youth

    NARCIS (Netherlands)

    Hermes, Joke; Graaf, Christa de

    2015-01-01

    This paper will query whether a dedicated news platform can attune to young people’s civic needs? That is to ask: can this be a space that follows a social media logic of conversation and ‘give and take’ – with producers and consumers changing roles or even losing the distinction? How could and woul

  10. Transforming business education to produce global managers

    NARCIS (Netherlands)

    Kedia, Ben L.; Englis-Danskin, Paula

    2011-01-01

    In recent years, globalization of businesses has occurred faster than the internationalization of business schools—in terms of faculty, students, and curriculum. Indeed, there is now a disconnect between global economic realities and the ability of business schools to produce global managers. This

  11. Poultry Producer. Ohio's Competency Analysis Profile.

    Science.gov (United States)

    Ohio State Univ., Columbus. Vocational Instructional Materials Lab.

    This Ohio Competency Analysis Profile (OCAP), derived from a modified Developing a Curriculum (DACUM) process, is a comprehensive and verified employer competency list for a poultry producer program. It contains units (with or without subunits), competencies, and competency builders that identify the occupational, academic, and employability…

  12. PV producers must advertise; Werbung wird wichtiger

    Energy Technology Data Exchange (ETDEWEB)

    Seltmann, T.

    2001-01-12

    Producers of current inverters are profiting from the growing PV market. The bigger suppliers are enhancing their advertising and marketing efforts while smaller suppliers opt for high-efficiency technology. [German] Vom kraeftigen Wachstum des Photovoltaik-Marktes profitieren zwangslaeufig auch die Wechselrichter-Hersteller. Die groesseren Anbieter verstaerken Vertrieb und Marketing, waehrend die kleineren versuchen, mit besonders effizienter Technik zu glaenzen. (orig.)

  13. Functionally graded materials produced by laser cladding

    NARCIS (Netherlands)

    Pei, Y.T.; Hosson, J.Th.M. De

    2000-01-01

    AlSi40 functionally graded materials (FGMs) were produced by a one-step laser cladding process on cast Al-alloy substrate as a possible solution for interfacial problems often present in laser coatings. The microstructure of the FGMs consists of a large amount of silicon primary particles surrounded

  14. An anaerobic mitochondrion that produces hydrogen

    NARCIS (Netherlands)

    Boxma, B.; Graaf, de R.M.; Staay, van der G.W.M.; Alen, T.A.; Richard, G.; Gabalon, T.; Hoek, van A.H.A.M.; Moon - van der Staay, S.Y.; Koopman, W.J.H.; Hellemond, van J.J.; Tielens, A.G.M.; Friedrich, T.; Veenhuis, M.; Huynen, M.A.; Hackstein, J.H.P.

    2005-01-01

    Hydrogenosomes are organelles that produce ATP and hydrogen(1), and are found in various unrelated eukaryotes, such as anaerobic flagellates, chytridiomycete fungi and ciliates(2). Although all of these organelles generate hydrogen, the hydrogenosomes from these organisms are structurally and metabo

  15. Chalco:Leading Nonferrous Metal Producer

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ China Aluminum Corporation Limited (Chalco) is an alumina producerand supplier holding the first place in China and the second place in the world. It is also a primary aluminum producer and supplier holding the first place in China and the sixth place in the world.

  16. Boron carbide whiskers produced by vapor deposition

    Science.gov (United States)

    1965-01-01

    Boron carbide whiskers have an excellent combination of properties for use as a reinforcement material. They are produced by vaporizing boron carbide powder and condensing the vapors on a substrate. Certain catalysts promote the growth rate and size of the whiskers.

  17. Producing biodiesel from soybeans in Zambia

    NARCIS (Netherlands)

    Drabik, Dusan; Gorter, de Harry; Timilsina, Govinda R.

    2016-01-01

    Facing a huge fiscal burden due to imports of its entire petroleum demand in the face of ample supply of agricultural land to produce biofuels, Zambia has recently introduced a biofuel mandate. However, a number of questions, particularly those related to the economics of biofuels, have not been

  18. Producing biodiesel from soybeans in Zambia

    NARCIS (Netherlands)

    Drabik, Dusan; Gorter, de Harry; Timilsina, Govinda R.

    2016-01-01

    Facing a huge fiscal burden due to imports of its entire petroleum demand in the face of ample supply of agricultural land to produce biofuels, Zambia has recently introduced a biofuel mandate. However, a number of questions, particularly those related to the economics of biofuels, have not been

  19. Produce Your Own: A Community Gardening Program

    Science.gov (United States)

    Miller, JoLynn; Arnold, Shannon

    2012-01-01

    Many County Extension offices offer an adult Master Gardener Program, which includes advanced gardening training, short courses, newsletters, and conferences. However, with the comprehensive training provided comes a large time commitment. The Produce Your Own program was created to introduce adults to gardening in a similar manner, but with…

  20. Carbapenemase-producing Organism in Food

    Centers for Disease Control (CDC) Podcasts

    2014-08-06

    Dr. Mike Miller reads an abridged version of the article, Carbapenemase-producing Organism in Food.  Created: 8/6/2014 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 8/13/2014.

  1. A reappraisal of fungi producing aflatoxins

    DEFF Research Database (Denmark)

    Varga, János; Frisvad, Jens Christian; Samson, Robert A.

    2009-01-01

    Aflatoxins are decaketide-derived secondary metabolites which are produced by a complex biosynthetic pathway. Aflatoxins are among the economically most important mycotoxins. Aflatoxin B1 exhibits hepatocarcinogenic and hepatotoxic properties, and is frequently referred to as the most potent natu...

  2. Silicon waveguides produced by wafer bonding

    DEFF Research Database (Denmark)

    Poulsen, Mette; Jensen, Flemming; Bunk, Oliver

    2005-01-01

    X-ray waveguides are successfully produced employing standard silicon technology of UV photolithography and wafer bonding. Contrary to theoretical expectations for similar systems even 100 mu m broad guides of less than 80 nm height do not collapse and can be used as one dimensional waveguides...

  3. Functionally graded materials produced by laser cladding

    NARCIS (Netherlands)

    Pei, Y.T.; Hosson, J.Th.M. De

    2000-01-01

    AlSi40 functionally graded materials (FGMs) were produced by a one-step laser cladding process on cast Al-alloy substrate as a possible solution for interfacial problems often present in laser coatings. The microstructure of the FGMs consists of a large amount of silicon primary particles surrounded

  4. Functionally Graded Materials Produced by Laser Cladding

    NARCIS (Netherlands)

    Pei, Y.T.; Hosson, J.Th.M. De

    2000-01-01

    AlSi40 functionally graded materials (FGMs) were produced by a one-step laser cladding process on cast Al-alloy substrate as a possible solution for interfacial problems often present in laser coatings. The microstructure of the FGMs consists of a large amount of silicon primary particles surrounded

  5. Pricing Electricity in Pools With Wind Producers

    DEFF Research Database (Denmark)

    Morales González, Juan Miguel; Conejo, A. J.; Kai Liu

    2012-01-01

    This paper considers an electricity pool that includes a significant number of wind producers and is cleared through a network-constrained auction, one day in advance and on an hourly basis. The hourly auction is formulated as a two-stage stochastic programming problem, where the first stage repr...

  6. Method of producing purified carotenoid compounds

    Science.gov (United States)

    Eggink, Laura (Inventor)

    2007-01-01

    A method of producing a carotenoid in solid form includes culturing a strain of Chlorophyta algae cells in a minimal inorganic medium and separating the algae comprising a solid form of carotenoid. In one embodiment f the invention, the strain of Chlorophyta algae cells includes a strain f Chlamydomonas algae cells.

  7. How Can We Best Produce Courseware?

    Science.gov (United States)

    Hitchens, Howard

    Several models exist for production methods that can be used in the development of instructional materials for use in television- or computer-based instructional programs. These models include the established audiovisual industry that currently produces educational films and similar materials; consortia of educational institutions sharing in the…

  8. Chemicals that produce anosmia in mosquitoes

    Science.gov (United States)

    The United States Department of Agriculture (USDA) has developed repellents and insecticides for the U.S. military since 1942. A small component of this research program has been focused on the discovery of attractants that can be used to produce potent lures for haematophagous arthropods, especial...

  9. CHARACTERIZING THE PSYCHOLOGICAL STATE PRODUCED BY LSD.

    Science.gov (United States)

    KATZ, MARTIN M.; AND OTHERS

    THE DEVELOPMENT AND COMPONENTS OF LYSERGIC ACID DIETHYLAMIDE (LSD) PRODUCED PSYCHOLOGICAL STATES ARE INVESTIGATED. THE SUBJECTS WERE PAID VOLUNTEERS FROM THE PATUXENT INSTITUTION, A TREATMENT CENTER FOR EMOTIONALLY UNSTABLE CRIMINAL OFFENDERS. IN ONE STUDY, GROUPS OF 23 SUBJECTS RECEIVED LSD, AN AMPHETAMINE, OR A PLACEBO. IN THE SECOND STUDY, 11…

  10. Methods of producing continuous boron carbide fibers

    Energy Technology Data Exchange (ETDEWEB)

    Garnier, John E.; Griffith, George W.

    2015-12-01

    Methods of producing continuous boron carbide fibers. The method comprises reacting a continuous carbon fiber material and a boron oxide gas within a temperature range of from approximately 1400.degree. C. to approximately 2200.degree. C. Continuous boron carbide fibers, continuous fibers comprising boron carbide, and articles including at least a boron carbide coating are also disclosed.

  11. Tower Power: Producing Fuels from Solar Energy

    Science.gov (United States)

    Antal, M. J., Jr.

    1976-01-01

    This article examines the use of power tower technologies for the production of synthetic fuels. This process overcomes the limitations of other processes by using a solar furnace to drive endothermic fuel producing reactions and the resulting fuels serve as a medium for storing solar energy. (BT)

  12. Transforming business education to produce global managers

    NARCIS (Netherlands)

    Kedia, Ben L.; Englis, Paula D.

    2011-01-01

    In recent years, globalization of businesses has occurred faster than the internationalization of business schools—in terms of faculty, students, and curriculum. Indeed, there is now a disconnect between global economic realities and the ability of business schools to produce global managers. This a

  13. Producing and Scrounging during Problem Based Learning

    Science.gov (United States)

    Vickery, William L.

    2013-01-01

    When problem based learning occurs in a social context it is open to a common social behaviour, scrounging. In the animal behaviour literature, scroungers do not attempt to find resources themselves but rather exploit resources found by other group members (referred to as producers). We know from studies of animal behaviour (including humans) that…

  14. Secondary Particles Produced by Hadron Therapy

    Directory of Open Access Journals (Sweden)

    Abdolkazem Ansarinejad

    2015-07-01

    Full Text Available Introduction Use of hadron therapy as an advanced radiotherapy technique is increasing. In this method, secondary particles are produced through primary beam interactions with the beam-transport system and the patient’s body. In this study, Monte Carlo simulations were employed to determine the dose of produced secondary particles, particularly neutrons during treatment. Materials and Methods In this study, secondary particles, produced by proton and ion beams, were simulated for a cancer treatment plan. In particular, we evaluated the distribution of secondary neutrons, produced by a 400 MeV/u carbon beam on an electronic crate, which was exposed to radiation field under radioactive conditions. The level of major secondary particles, particularly neutrons, irradiating the target, was evaluated, using FLUKA Monte Carlo code. Results The fluences and radiation doses were applied to determine the shielding efficiency of devices and the probability of radiation damage to nearby electronic systems. According to the results, by using maximum-energy carbon ions (400 MeV/u, electronic devices are exposed to a dose rate of 0.05 µSv/s and an integrated dose of about 34 mSv, each year. Conclusion The simulation results could provide significant information about radiation assessment; they could also be a major help for clinical facilities to meet shielding requirements. Moreover, such simulations are essential for determining the radiation level, which is responsible for radiation-induced damages.

  15. User producer interaction in context: a classification

    NARCIS (Netherlands)

    Nahuis, Roel; Moors, Ellen; Smits, Ruud

    2009-01-01

    Science, Technology and Innovation Studies show that intensified user producer interaction (UPI) increases chances for successful innovations, especially in the case of emerging technology. It is not always clear, however, what type of interaction is necessary in a particular context. This paper pro

  16. Method of producing a chemical hydride

    Science.gov (United States)

    Klingler, Kerry M.; Zollinger, William T.; Wilding, Bruce M.; Bingham, Dennis N.; Wendt, Kraig M.

    2007-11-13

    A method of producing a chemical hydride is described and which includes selecting a composition having chemical bonds and which is capable of forming a chemical hydride; providing a source of a hydrocarbon; and reacting the composition with the source of the hydrocarbon to generate a chemical hydride.

  17. Producing Student Films: Shakespeare on Screen.

    Science.gov (United States)

    Franek, Mark

    1996-01-01

    Makes a case for asking students to produce their own film version of Shakespeare's "A Midsummer Night's Dream." Explains how to manage student filming projects logistically; how to teach students about filming techniques through the study of modern movies; and how filming becomes a lesson in the interpretation of Shakespeare. (TB)

  18. The Top American Indian Degree Producers

    Science.gov (United States)

    Diverse: Issues in Higher Education, 2012

    2012-01-01

    Each year, "Diverse: Issues In Higher Education" publishes lists of the Top 100 producers of associate, bachelor's and graduate degrees awarded to minority students based on research conducted by Dr. Victor M.H. Borden, professor of educational leadership and policy studies at the Indiana University Bloomington. This year, Diverse staff…

  19. Process and apparatus for producing coated particles

    NARCIS (Netherlands)

    Van Ommen, J.R.; Ellis, N.; Yurteri, C.; Marijnissen, J.C.M.

    2010-01-01

    The invention is directed to a process and apparatus for preparing coated particles, in particular a process for preparing particles that are coated with small particles using electrospraying. The coated particles produced according to the present invention find use for instance as catalysts or as

  20. Process for producing a fried foodstuff

    NARCIS (Netherlands)

    Eijck, van P.C.M.; Waele, de E.T.

    1997-01-01

    A process for producing fried starch-containing foodstuffs is described, comprising a thermal treatment resulting in gelatinisation of starch, partial frying, cooling, optional freezing and optional finishing, wherein the foodstuff is subjected to a mechanical surface treatment between said thermal

  1. 7 CFR 955.9 - Producer.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Producer. 955.9 Section 955.9 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE VIDALIA ONIONS GROWN IN GEORGIA...

  2. How to Produce a Small Newspaper.

    Science.gov (United States)

    Miller, Edward; And Others

    A how-to manual for people interested in the mechanics of newspaper production, this book was produced by the editors of a small town newspaper. Chapters about content, printing, typography, pasteup, design and layout, advertising, circulation and distribution, financial matters, and deadlines contain practical discussions of details such as what…

  3. Biologically produced sulfur particles and polysulfide ions

    NARCIS (Netherlands)

    Kleinjan, W.E.

    2005-01-01

    This thesis deals with the effects of particles of biologically produced sulfur (or 'biosulfur') on a biotechnological process for the removal of hydrogen sulfide from gas streams. Particular emphasis is given to the role of polysulfide ions in such a process. These polysul

  4. Process of producing mannitol and homopolysaccharides

    NARCIS (Netherlands)

    Geel-Schutten, Gerritdina Hendrika van; Binnema, Doede J.; van der Maarel, Marc

    2004-01-01

    The present invention relates to a process producing mannitol and one or more homopolysaccharides by bacteria. The bacteria according to the invention express mannitol-2-dehydrogenase activity and one or more sucrase activities. Preferably, the bacteria are lactic acid bacteria and more preferably t

  5. Biologically produced sulfur particles and polysulfide ions

    NARCIS (Netherlands)

    Kleinjan, W.E.

    2005-01-01

    This thesis deals with the effects of particles of biologically produced sulfur (or 'biosulfur') on a biotechnological process for the removal of hydrogen sulfide from gas streams. Particular emphasis is given to the role of polysulfide ions in such a process. These

  6. Beneficial Reuse of San Ardo Produced Water

    Energy Technology Data Exchange (ETDEWEB)

    Robert A. Liske

    2006-07-31

    This DOE funded study was performed to evaluate the potential for treatment and beneficial reuse of produced water from the San Ardo oilfield in Monterey County, CA. The potential benefits of a successful full-scale implementation of this project include improvements in oil production efficiency and additional recoverable oil reserves as well as the addition of a new reclaimed water resource. The overall project was conducted in two Phases. Phase I identified and evaluated potential end uses for the treated produced water, established treated water quality objectives, reviewed regulations related to treatment, transport, storage and use of the treated produced water, and investigated various water treatment technology options. Phase II involved the construction and operation of a small-scale water treatment pilot facility to evaluate the process's performance on produced water from the San Ardo oilfield. Cost estimates for a potential full-scale facility were also developed. Potential end uses identified for the treated water include (1) agricultural use near the oilfield, (2) use by Monterey County Water Resources Agency (MCWRA) for the Salinas Valley Water Project or Castroville Seawater Intrusion Project, (3) industrial or power plant use in King City, and (4) use for wetlands creation in the Salinas Basin. All of these uses were found to have major obstacles that prevent full-scale implementation. An additional option for potential reuse of the treated produced water was subsequently identified. That option involves using the treated produced water to recharge groundwater in the vicinity of the oil field. The recharge option may avoid the limitations that the other reuse options face. The water treatment pilot process utilized: (1) warm precipitation softening to remove hardness and silica, (2) evaporative cooling to meet downstream temperature limitations and facilitate removal of ammonia, and (3) reverse osmosis (RO) for removal of dissolved salts, boron

  7. Characterization of aerosols produced by surgical procedures

    Energy Technology Data Exchange (ETDEWEB)

    Yeh, H.C.; Muggenburg, B.A.; Lundgren, D.L.; Guilmette, R.A.; Snipes, M.B.; Jones, R.K. [Inhalation Toxicology Research Institute, Albuquerque, NM (United States); Turner, R.S. [Lovelace Health Systems, Albuquerque, NM (United States)

    1994-07-01

    In many surgeries, especially orthopedic procedures, power tools such as saws and drills are used. These tools may produce aerosolized blood and other biological material from bone and soft tissues. Surgical lasers and electrocautery tools can also produce aerosols when tissues are vaporized and condensed. Studies have been reported in the literature concerning production of aerosols during surgery, and some of these aerosols may contain infectious material. Garden et al. (1988) reported the presence of papilloma virus DNA in the fumes produced from laser surgery, but the infectivity of the aerosol was not assessed. Moon and Nininger (1989) measured the size distribution and production rate of emissions from laser surgery and found that particles were generally less than 0.5 {mu}m diameter. More recently there has been concern expressed over the production of aerosolized blood during surgical procedures that require power tools. In an in vitro study, the production of an aerosol containing the human immunodeficiency virus (HIV) was reported when power tools were used to cut tissues with blood infected with HIV. Another study measured the size distribution of blood aerosols produced by surgical power tools and found blood-containing particles in a number of size ranges. Health care workers are anxious and concerned about whether surgically produced aerosols are inspirable and can contain viable pathogens such as HIV. Other pathogens such as hepatitis B virus (HBV) are also of concern. The Occupational Safety and Health funded a project at the National Institute for Inhalation Toxicology Research Institute to assess the extent of aerosolization of blood and other tissues during surgical procedures. This document reports details of the experimental and sampling approach, methods, analyses, and results on potential production of blood-associated aerosols from surgical procedures in the laboratory and in the hospital surgical suite.

  8. Dominance of IMP-4-Producing Enterobacter cloacae among Carbapenemase-Producing Enterobacteriaceae in Australia

    Science.gov (United States)

    Townell, Nicola; Nimmo, Graeme R.; George, Narelle M.; Robson, Jennifer; Vohra, Renu; Davis, Louise; Heney, Claire; Paterson, David L.

    2015-01-01

    The prevalence of carbapenemase-producing Enterobacteriaceae (CPE) has been increasing worldwide. blaIMP has been reported to be the predominant carbapenemase-encoding gene within Enterobacteriaceae in Australia. However, there are limited data currently available on CPE from Queensland, Australia. A total of 58 CPE isolates were isolated between July 2009 and March 2014 from Queensland hospitals. The clonality of isolates was determined by Diversilab repetitive sequence-based PCR. The isolates were investigated for the resistance mechanisms carbapenemase, extended-spectrum β-lactamase, and AmpC β-lactamase and for aminoglycoside resistance and plasmid-mediated quinolone resistance genes by PCR. The plasmid types associated with carbapenemase-encoding genes were characterized. The majority of the CPE were Enterobacter cloacae (n = 29). The majority of Queensland CPE isolates were IMP producers and comprised 11 species (n = 48). Nine NDM-producing Enterobacteriaceae were identified. One NDM-producing Klebsiella pneumoniae isolate coproduced OXA-48. One K. pneumoniae isolate was an OXA-181 producer. The incidence of IMP producers increased significantly in 2013. blaIMP-4 was found in all IMP-producing isolates. blaTEM, qnrB, and aacA4 were common among IMP-4 producers. The HI2 (67%) and L/M (21%) replicons were associated with blaIMP-4. All HI2 plasmids were of sequence type 1 (ST1). All but one of the NDM producers possessed blaCTX-M-15. The 16S rRNA methylase genes found among NDM producers were armA, rmtB, rmtC, and rmtF. The substantial increase in the prevalence of CPE in Queensland has been associated mainly with the emergence E. cloacae strains possessing HI2 plasmids carrying blaIMP-4 over the past 2 years. The importation of NDM producers and/or OXA-48-like producers in patients also contributed to the increased emergence of CPE. PMID:25918153

  9. Monetary Shocks in Models with Inattentive Producers.

    Science.gov (United States)

    Alvarez, Fernando E; Lippi, Francesco; Paciello, Luigi

    2016-04-01

    We study models where prices respond slowly to shocks because firms are rationally inattentive. Producers must pay a cost to observe the determinants of the current profit maximizing price, and hence observe them infrequently. To generate large real effects of monetary shocks in such a model the time between observations must be long and/or highly volatile. Previous work on rational inattentiveness has allowed for observation intervals that are either constant-but-long (e.g. Caballero, 1989 or Reis, 2006) or volatile-but-short (e.g. Reis's, 2006 example where observation costs are negligible), but not both. In these models, the real effects of monetary policy are small for realistic values of the duration between observations. We show that non-negligible observation costs produce both of these effects: intervals between observations are infrequent and volatile. This generates large real effects of monetary policy for realistic values of the average time between observations.

  10. Sounds energetic: the radio producer's energy minibook

    Energy Technology Data Exchange (ETDEWEB)

    1980-12-01

    The Minibook will be expanded into the final Radio Producer's Energy Sourcebook. Radio producers and broadcasters are asked to contribute ideas for presenting energy knowledge to the public and to be included in the Sourcebook. Chapter One presents a case study suggesting programming and promotion ideas and sample scripts for a radio campaign that revolves around no-cost or low-cost steps listeners can take to increase their home energy efficiency and save money. A variety of other energy topics and suggestions on ways to approach them are addressed in Chapter Two. Chapter Three contains energy directories for Baltimore, Philadelphia, Pittsburg, and Washington, DC. The directories will be expanded in the Sourcebook and will consist of a selection of local public and private sector energy-related organizations and list local experts and organizations and the best Federal, state, and local government programs that can provide consumers and citizens groups with information, technical assistance, and financial support. (MCW)

  11. Calcitonin produces hypercalcemia in leopard sharks.

    Science.gov (United States)

    Glowacki, J; O'Sullivan, J; Miller, M; Wilkie, D W; Deftos, L J

    1985-02-01

    Calcitonin was detected by RIA in sera from four marine species, leopard sharks (Triakis semifasciata), horn sharks (Heterodontus francisci), thornback rays (Platyrhinoides triseriata), and kelp bass (Paralabrax clathratus). These animals have levels of calcitonin and calcium higher than freshwater and terrestrial species have. The administration of salmon calcitonin to bass (4 micrograms/kg BW) produced hypocalcemia and hypophosphatemia as has been reported for other bony vertebrates. In marked contrast, calcitonin produced a prompt hypercalcemia in sharks; the average was 9.8% increase in serum calcium in nine animals with no attendant change in phosphorus. These findings demonstrate that calcitonin can increase serum calcium in sharks. Because shark skeleton is composed of cartilage, this hypercalcemic effect of calcitonin does not require a bony skeleton.

  12. Bacillus subtilis as potential producer for polyhydroxyalkanoates

    Directory of Open Access Journals (Sweden)

    Patel Sanjay KS

    2009-07-01

    Full Text Available Abstract Polyhydroxyalkanoates (PHAs are biodegradable polymers produced by microbes to overcome environmental stress. Commercial production of PHAs is limited by the high cost of production compared to conventional plastics. Another hindrance is the brittle nature and low strength of polyhydroxybutyrate (PHB, the most widely studied PHA. The needs are to produce PHAs, which have better elastomeric properties suitable for biomedical applications, preferably from inexpensive renewable sources to reduce cost. Certain unique properties of Bacillus subtilis such as lack of the toxic lipo-polysaccharides, expression of self-lysing genes on completion of PHA biosynthetic process – for easy and timely recovery, usage of biowastes as feed enable it to compete as potential candidate for commercial production of PHA.

  13. Characterization of briquettes produced with agroforestry residues

    Directory of Open Access Journals (Sweden)

    Ananias Francisco Dias Júnior

    2014-09-01

    Full Text Available The objective of the present was to characterize the quality of briquettes produced with fines of vegetable coal and bamboo residues, under different formulations. Specific gravity density, bulk density mass, moisture content and speed or rate of thermic degradation were evaluated. Compressive strength and rotation test were applied to the briquettes. Superior and inferior calorific values from briquettes were estimate by adjusted equations. Briquettes produced with the highest percentages of vegetable coal fines presented higher specific gravity, bulk density, ash content and fixed carbon. It also presented resistance to fall and abrasion. Briquettes with higher bamboo residues content presented faster degradation, higher compressive strength, beyond higher volatile matters and calorific value.

  14. Method for producing catalysis from coal

    Science.gov (United States)

    Farcasiu, Malvina; Derbyshire, Frank; Kaufman, Phillip B.; Jagtoyen, Marit

    1998-01-01

    A method for producing catalysts from coal is provided comprising mixing an aqueous alkali solution with the coal, heating the aqueous mixture to treat the coal, drying the now-heated aqueous mixture, reheating the mixture to form carbonized material, cooling the mixture, removing excess alkali from the carbonized material, and recovering the carbonized material, wherein the entire process is carried out in controlled atmospheres, and the carbonized material is a hydrocracking or hydrodehalogenation catalyst for liquid phase reactions. The invention also provides for a one-step method for producing catalysts from coal comprising mixing an aqueous alkali solution with the coal to create a mixture, heating the aqueous mixture from an ambient temperature to a predetermined temperature at a predetermined rate, cooling the mixture, and washing the mixture to remove excess alkali from the treated and carbonized material, wherein the entire process is carried out in a controlled atmosphere.

  15. Rhamnolipid Biosurfactants Produced by Pseudomonas Species

    Directory of Open Access Journals (Sweden)

    Banu Kaskatepe

    Full Text Available ABSTRACT: Surfactants are chemical products widely used in our daily life in toothpaste and other personal hygiene and cosmetic products, and in several industries. Biosurfactants are surfactants of biological origin that can be produced by microorganisms and have many advantages, such as low toxicity and high biodegradability, compared to synthetic counterparts. Unfortunately, high production costs limit the use of biosurfactants. Low-cost production is the most important factor for biosurfactants to be able to compete in the global market place. This review presents general information on rhamnolipid biosurfactant produced by Pseudomonas species, as well as on their production and applications. In addition, industrial products and their wastes used for rhamnolipid production are reviewed in detail based on recent studies.

  16. Microwave Semiconductor Equipment Produced in Poland,

    Science.gov (United States)

    1984-01-20

    lQal signal source in other devices. Microwave Transistors As a result of work in the field of microwave transistors , the technology for pnp ...is now commonly carried out on transistors and microwave subsystems. The results of the labors of the DM section connected with the new devices and...level of employment Illustration 2. Microwave diodes and semiconductor transistors presently produced in the ITE (DM section) The Construction and

  17. Cyanobacteria blooms produce teratogenic retinoic acids.

    Science.gov (United States)

    Wu, Xiaoqin; Jiang, Jieqiong; Wan, Yi; Giesy, John P; Hu, Jianying

    2012-06-12

    Deformed amphibians have been observed in eutrophic habitats, and some clues point to the retinoic acids (RAs) or RA mimics. However, RAs are generally thought of as vertebrate-specific hormones, and there was no evidence that RAs exist in cyanobacteria or algae blooms. By analyzing RAs and their analogs 4-oxo-RAs in natural cyanobacteria blooms and cultures of cyanobacteria and algae, we showed that cyanobacteria blooms could produce RAs, which were powerful animal teratogens. Intracellular RAs and 4-oxo-RAs with concentrations between 0.4 and 4.2 × 10(2) ng/L were detected in all bloom materials, and extracellular concentrations measured in water from Taihu Lake, China, were as great as 2.0 × 10 ng/L, which might pose a risk to wildlife through chronic exposure. Further examination of 39 cyanobacteria and algae species revealed that 32 species could produce RAs and 4-oxo-RAs (1.6-1.4 × 10(3) ng/g dry weight), and the dominant cyanobacteria species in Taihu Lake, Microcystis flos-aquae and Microcystis aeruginosa, produced high amounts of RAs and 4-oxo-RAs with concentrations of 1.4 × 10(3) and 3.7 × 10(2) ng/g dry weight, respectively. Most genera of cyanobacteria that could produce RAs and 4-oxo-RAs, such as Microcystis, Anabaena, and Aphanizomenon, often occur dominantly in blooms. Production of RAs and 4-oxo-RAs by cyanobacteria was associated with species, origin location, and growth stage. These results represent a conclusive demonstration of endogenous production of RAs in freshwater cyanobacteria blooms. The observation of teratogenic RAs in cyanobacteria is evolutionarily and ecologically significant because RAs are vertebrate-specific hormones, and cyanobacteria form extensive and highly visible blooms in many aquatic ecosystems.

  18. Pheromone produced by the myxobacterium Stigmatella aurantiaca.

    OpenAIRE

    Stephens, K.; Hegeman, G D; White, D

    1982-01-01

    An extracellular, diffusible signaling molecule (pheromone) was produced by Stigmatella aurantiaca during fruiting body formation. The pheromone decreased the aggregation period in both the light and the dark and substituted for light in stimulating the maturation of aggregates into fruiting bodies. The cells were more sensitive to lower concentrations of pheromone in the light than in the dark, possibly explaining the stimulation of aggregation and fruiting body formation by light. The phero...

  19. Interference to satellite systems produced by rainscatter

    Science.gov (United States)

    Howell, R. G.; Thompson, P. T.

    1991-10-01

    Data, obtained from eight small dish receivers, placed around the United Kingdom, and designed to detect the scattering by rain of signals from the British Telecom (BT) 11 GHz microwave network, is presented. Fifteen site years of measurements were analyzed to produce cumulative distributions of effective receive antenna noise temperature and, where rainscattered signals were detected, cumulative distributions of transmission loss. The results obtained are compared with those predicted by a BT/University of Essex rainscatter interference prediction model (SCIMP).

  20. Method of producing microchannel and nanochannel articles

    Science.gov (United States)

    D'Urso, Brian R.

    2010-05-04

    A method of making an article having channels therethrough includes the steps of: providing a ductile structure defining at least one macro-channel, the macro-channel containing a salt; drawing the ductile structure in the axial direction of the at least one macro-channel to reduce diameter of the macro-channel; and contacting the salt with a solvent to dissolve the salt to produce an article having at least one microchannel.

  1. Adventures in Laser Produced Plasma Research

    Energy Technology Data Exchange (ETDEWEB)

    Key, M

    2006-01-13

    In the UK the study of laser produced plasmas and their applications began in the universities and evolved to a current system where the research is mainly carried out at the Rutherford Appleton Laboratory Central Laser Facility ( CLF) which is provided to support the universities. My own research work has been closely tied to this evolution and in this review I describe the history with particular reference to my participation in it.

  2. Investigate Nasal Colonize Staphylococcus Species Biofilm Produced

    Directory of Open Access Journals (Sweden)

    Cemil Demir

    2014-03-01

    Full Text Available Aim: 127 S.aureus and 65 CoNS strains were isolated from patients noses%u2019. To produce a biofilm ability was investigated using three different methods. Slime-positive and negative staphylococcies%u2019 resistance were evaluated against different antibiotics. Material and Method: Swap samples puted 7% blood agar. Staphylococcus aureus and coagulase-negative staphylococci (CoNS isolates biofilm produced ability were investigated using Congo Red Agar (CRA, microplates (MP and Standard Tube (ST methods. In addition to that, presence of antibiotic resistance of the staphylococcal isolates are determined agar disc diffusion method. Results: The rate of biofilm producing Staphylococcus spp strains was found to be 72.4%, 67.7%, and 62.9%, respectively with CRA, MP, and ST tests. There was no significant relationship among the tests (p>0.05. In addition, antibiotic resistance of Staphylococcus spp. against various antibiotics was also determined by the agar disk diffusion method. Resistance rates of biofilm positive (BP Staphylococcus spp for penicilin G, ampicilin, amocycilin/clavulanic acid, tetracyclin, eritromycin, gentamycin, and enrofloxacin 71.7%, 69.7%, 6.2%, 20.7%, 21.4%, 1.4%, and 0.7%, respectively. Resistance rates of biofilm negative (BN spp for 42.6%, 23.4%, 4.3%, 14.9%, 19.1%, 0.0%, 0.0% respectively. All Staphylococcus isolates were found to be susceptible to vancomycin and teicaplonin. Although BP strains antibiotic resistance rates were observed higher than BN strains. But resistance rates were not found statistically significant (p>0.05. Discussion: CRA is the reliablity and specifity method to determine Staphylococcus spp. biofilm produce ability.

  3. Separation of a tungus producing taxol

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    An endogenous filariform fungus has been separated from a treenamed Taxus growing in the Aba region, Sichuan, China. The fungus is fermented in fluid medium for 3 weeks at 25℃, then the HPLC and MALDI-TOF analysis of the zymotic fluid show that the zymotic fluid contains taxol. So it is a fungus which can produce taxol. It is named Taxomyces sp. temporarily.

  4. KPC-producing Enterobacter aerogenes infection

    OpenAIRE

    Tuon, Felipe F.; Camila Scharf; Jaime L. Rocha; Juliette Cieslinsk; Guilherme Nardi Becker; Arend,Lavinia N.

    2015-01-01

    Background: Enterobacteris a common nosocomial microorganism and its carbapenem's resistance has increased. The management of these cases is unclear.Objective: We evaluated 16 patients with KPC-producing Enterobacter aerogenesinfections, detailing the site of infection, therapy, clinical and epidemiological data.Methods: A retrospective and descriptive study. Clinical data were revised and KPC-2 detection was by molecular methods. Risk factors associated with mortality were compared using app...

  5. Producing a solid fuel from agricultural wastes

    Energy Technology Data Exchange (ETDEWEB)

    Khigasikuni, T.; Fudziki, A.; Koisi, K.

    1982-08-21

    Agricultural wastes, in particular, the peels and seeds of mandarine oranges, used for canning, were ground, dried, mixed with a binder, molded in cylindrical or pyramidal forms of a piece of the desired size, heated and impregnated with a water repellant substance, for instance, paraffin. A material is produced with a d = 1. PVA was used as the binder. The wastes were partially gasified and the obtained gas was used as a heat source in drying the wastes.

  6. Structural properties of produced CuO/NiO/glass thin layers Produced by chemical method

    Directory of Open Access Journals (Sweden)

    A. Ramezani

    2016-12-01

    Full Text Available Nickel Oxide and Copper oxide on Nickel Oxide thin layers were produced by chemical bath deposition method. There nano structures were investigated by SEM and EDAX analysis. By producing CuO/NiO/glass sandwich layers nano structure of NiO/glass layer changed and fraction of voids decreases. In sandwich layer physical property of outer layer was dominant

  7. Consumer's Fresh Produce Food Safety Practices: Outcomes of a Fresh Produce Safety Education Program

    Science.gov (United States)

    Scott, Amanda R.; Pope, Paul E.; Thompson, Britta M.

    2009-01-01

    The Centers for Disease Control and Prevention estimate that there are 76 million cases of foodborne disease annually. Foodborne disease is usually associated with beef, poultry, and seafood. However, there is an increasing number of foodborne disease cases related to fresh produce. Consumers may not associate fresh produce with foodborne disease…

  8. Consumer's Fresh Produce Food Safety Practices: Outcomes of a Fresh Produce Safety Education Program

    Science.gov (United States)

    Scott, Amanda R.; Pope, Paul E.; Thompson, Britta M.

    2009-01-01

    The Centers for Disease Control and Prevention estimate that there are 76 million cases of foodborne disease annually. Foodborne disease is usually associated with beef, poultry, and seafood. However, there is an increasing number of foodborne disease cases related to fresh produce. Consumers may not associate fresh produce with foodborne disease…

  9. Pervaporation of ethanol produced from banana waste.

    Science.gov (United States)

    Bello, Roger Hoel; Linzmeyer, Poliana; Franco, Cláudia Maria Bueno; Souza, Ozair; Sellin, Noeli; Medeiros, Sandra Helena Westrupp; Marangoni, Cintia

    2014-08-01

    Banana waste has the potential to produce ethanol with a low-cost and sustainable production method. The present work seeks to evaluate the separation of ethanol produced from banana waste (rejected fruit) using pervaporation with different operating conditions. Tests were carried out with model solutions and broth with commercial hollow hydrophobic polydimethylsiloxane membranes. It was observed that pervaporation performance for ethanol/water binary mixtures was strongly dependent on the feed concentration and operating temperature with ethanol concentrations of 1-10%; that an increase of feed flow rate can enhance the permeation rate of ethanol with the water remaining at almost the same value; that water and ethanol fluxes was increased with the temperature increase; and that the higher effect in flux increase was observed when the vapor pressure in the permeate stream was close to the ethanol vapor pressure. Better results were obtained with fermentation broth than with model solutions, indicated by the permeance and membrane selectivity. This could be attributed to by-products present in the multicomponent mixtures, facilitating the ethanol permeability. By-products analyses show that the presence of lactic acid increased the hydrophilicity of the membrane. Based on this, we believe that pervaporation with hollow membrane of ethanol produced from banana waste is indeed a technology with the potential to be applied.

  10. Beneficial Reuse of San Ardo Produced Water

    Energy Technology Data Exchange (ETDEWEB)

    Robert A. Liske

    2003-09-26

    This report summarizes the work performed from 1 April 2003 to 30 September 2003 and recommends the tasks to be performed during Phase II (Pilot Evaluation). During this period discussions were held with various water agencies regarding use of the treated produced water either directly or indirectly through a water trading arrangement. In particular, several discussions were held with Monterey County Water Resources Agency, that has been charged with the long-term management and preservation of water resources in Monterey County. The Agency is very supportive of the program. However, they would like to see water quality/cost estimate data for the treated produced water from the pilot study prior to evaluating water use/water trade options. The agency sent a letter encouraging the project team to perform the pilot study to evaluate feasibility of the project. In addition, the regulations related to use of the treated water for various applications were updated during this period. Finally, the work plan, health and safety plan and sample analyses plan for performing pilot study to treat the oilfield produced water were developed during this period.

  11. Social inclusion policy: Producing justice or retribution?

    Directory of Open Access Journals (Sweden)

    Kym Macfarlane

    2010-10-01

    Full Text Available The notion of social inclusion has currently gained extraordinary credence in Australia. Policy incorporating social inclusion abounds across all discipline areas with the federal government for the first time instituting a government portfolio for this area, headed by the Deputy Prime Minister. Such a move indicates the importance of managing aspects of inclusion across all sectors, in a country where diversity abounds. However, this focus on inclusion can prove highly problematic, when it becomes such an integral part of policy formulation and of the assumptions, omissions and contradictions that policy produces. This paper examines how policy discourse produces ways of thinking about inclusion/exclusion. Using three vignettes, the author applies the theories of Michel Foucault to argue that the discursive production of such inclusive policy works to simultaneously exclude by categorising particular types of individuals and families as “proper” participants in society. The author contends that understandings of propriety relating to the inclusion/exclusion binary reinscribe each other, in ways that situate particular citizens outside of possibilities for “success” in social and systemic participation. Such understanding is highlighted by a conceptual examination of the ways in which discursively produced notions of propriety become normalised. Keywords: bricolage, discourse, authorised knowledge, imperative discourse, regimes of truth

  12. PIVKA-II-producing advanced gastric cancer.

    Science.gov (United States)

    Takano, Shigetsugu; Honda, Ichiro; Watanabe, Satoshi; Soda, Hiroaki; Nagata, Matsuo; Hoshino, Isamu; Takenouchi, Toshinao; Miyazaki, Masaru

    2004-08-01

    We describe the case of a 68-year-old man with primary advanced adenocarcinoma of the stomach, who displayed extremely high plasma levels of protein induced by vitamin K antagonist (PIVKA)-II (15 600 mAU/ml) and normal levels of alphafetoprotein (AFP) (4 ng/ml). Ultrasonography and dynamic computed tomography ruled out hepatocellular carcinoma (HCC) or liver metastasis. After preoperative chemotherapy, pancreatico-spleno total gastrectomy with D2 lymphadenectomy was performed. Postoperatively, plasma levels of PIVKA-II returned to within the normal range (29 mAU/ml). Microscopic examination revealed stomach adenocarcinoma showing various histological types, such as moderately to poorly differentiated mucinous adenocarcinoma, but hepatoid differentiation of gastric adenocarcinoma was not detected. Localization of PIVKA-II and AFP within tumor cells was demonstrated by immunohistochemical staining using monoclonal antibodies. These results indicate that tumor cells from gastric cancer may produce PIVKA-II. Some cases of PIVKA-II- and AFP-producing advanced gastric cancer with liver metastasis have been reported, but this is the first report of gastric cancer without liver metastasis producing PIVKA-II alone.

  13. Bioethanol produced from Moringa oleifera seeds husk

    Science.gov (United States)

    Ali, E. N.; Kemat, S. Z.

    2017-06-01

    This paper presents the potential of bioethanol production from Moringa oleifera seeds husk which contains lignocellulosic through Simultaneous Saccharification and Fermentation (SSF) process by using Saccharomyces cerevisiae. This paper investigates the parameters which produce optimum bioethanol yield. The husk was hydrolyzed using NaOH and fermented using Saccharomyces cerevisiae yeast. Batch fermentation was performed with different yeast dosage of 1, 3, and 5 g/L, pH value was 4.5, 5.0 and 5.5, and fermentation time of 3, 6, 9 and 12 hours. The temperature of fermentation process in incubator shaker is kept constant at 32ºC. The samples are then filtered using a 0.20 μm nylon filter syringe. The yield of bioethanol produced was analysed using High Performance Liquid Chromatography (HPLC). The results showed that the highest yield of 29.69 g/L was obtained at 3 hours of fermentation time at pH of 4.5 and using 1g/L yeast. This research work showed that Moringa oleifera seeds husk can be considered to produce bioethanol.

  14. Radioactivity monitoring of Irish dairy produce

    Energy Technology Data Exchange (ETDEWEB)

    Kelleher, K. (Radiological Protection Institute of Ireland. Radiation Monitoring, Dublin (Ireland))

    2010-03-15

    Full text: The RPII has been carrying out monitoring of milk and dairy produce since 1986. Milk samples are routinely analysed for radiocaesium and strontium-90 as part of the RPII's environmental monitoring programme to determine the doses received to the Irish population from milk consumption. The method the RPII utilises for determining the Sr-90 activity in milk is by measuring the Cerenkov radiation produced by its daughter 90Y isolated from interfering nuclides such as uranium, thorium, radium and their decay products as well as isotopes of caesium, potassium and strontium by extraction with 10% di-(2-ethylhexyl)phosphate (HDEHP) in toluene. The chemical yield of 90Y is determined by the acidmetric titration of yttrium nitrate carrier with titriplex III. The levels of Sr-90 and dose to the Irish population from milk consumption have been negligible when compared to other radioactive sources in the Irish environment. Other dairy products are analysed for radiocaesium on a routine basis for commercial customers to ensure the levels of radioactivity in the dairy products fall within EC regulations governing the export/import of dairy produce. The export of milk and milk produce from Ireland is a very important industry, 80% of dairy products produced in Ireland are exported and these exports are worth Euro 2.2 billion annually to the Irish economy. The dairy products are analysed by gamma spectroscopy and include full and skim milk powders, butter, casein, cheese, cream, whey and lactose. The levels of radiocaesium in these products are typically below 5 Bk/kg and fall well within the limit of 370 Bq/kg laid down by the European Community in Council Regulation 737/90. Although the levels of these radionuclides are relatively low the RPII recognises the importance of analysing these samples for radioactivity to inform the public, ensure consumer confidence and, more importantly, to maintain a level of expertise in the RPII in these analytical techniques so

  15. 不同的文化背景,相似的悲剧命运——尤金·奥尼尔的《榆树下的欲望》和曹禺的《雷雨》之比较%Different Cultural Backgrounds yet Similar Tragic Fates——Comparison of O'Neill's Desire Under the Elms and Tsao Yu's Thunderstorm

    Institute of Scientific and Technical Information of China (English)

    刘翠兰

    2007-01-01

    This paper focuses on comparing Desire Under the Elms written by the great American playwright Eugene O'Neill and Thunderstorm by the well-known Chinese playwright Tsao Yu.Though set in two different cultural backgrounds,the two dramas share many similarities in the themes,the creation of characters and the dramatic stage techniques.%本文就美国戏剧大师尤金·奥尼尔的《榆树下的欲望》和中国戏剧家曹禺的作品《雷雨》进行了比较.虽然两部戏剧发生在不同的文化背景中,但其主题、人物创造和戏剧舞台技艺却极其相似.

  16. Treatment of Oil & Gas Produced Water.

    Energy Technology Data Exchange (ETDEWEB)

    Dwyer, Brian P. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-02-01

    Production of oil and gas reserves in the New Mexico Four Corners Region results in large volumes of "produced water". The common method for handling the produced water from well production is re-injection in regulatory permitted salt water disposal wells. This is expensive (%7E $5/bbl.) and does not recycle water, an ever increasingly valuable commodity. Previously, Sandia National Laboratories and several NM small business tested pressure driven membrane-filtration techniques to remove the high TDS (total dissolved solids) from a Four Corners Coal Bed Methane produced water. Treatment effectiveness was less than optimal due to problems with pre-treatment. Inadequate pre-treatment allowed hydrocarbons, wax and biological growth to foul the membranes. Recently, an innovative pre-treatment scheme using ozone and hydrogen peroxide was pilot tested. Results showed complete removal of hydrocarbons and the majority of organic constituents from a gas well production water. ACKNOWLEDGEMENTS This report was made possible through funding from the New Mexico Small Business Administration (NMSBA) Program at Sandia National Laboratories. Special thanks to Juan Martinez and Genaro Montoya for guidance and support from project inception to completion. Also, special thanks to Frank McDonald, the small businesses team POC, for laying the ground work for the entire project; Teresa McCown, the gas well owner and very knowledgeable- fantastic site host; Lea and Tim Phillips for their tremendous knowledge and passion in the oil & gas industry.; and Frank Miller and Steve Addleman for providing a pilot scale version of their proprietary process to facilitate the pilot testing.

  17. Bupropion hydrochloride produces conditioned hyperactivity in rats.

    Science.gov (United States)

    Wilkinson, Jamie L; Bevins, Rick A

    2007-04-23

    Bupropion is marketed as an antidepressant, Wellbutrin and smoking cessation aid, Zyban. Although the therapeutic neurological mechanisms of bupropion have not been fully elucidated, bupropion shares some behavioral similarities with classic psychomotor stimulants. The present study sought to further investigate these psychomotor stimulant effects of bupropion by assessing whether repeated administration of bupropion in a distinct environment produced conditioned hyperactivity. Paired rats received 10 daily i.p. injections of bupropion (2.5-30 mg/kg) before placement in locomotor chambers for 30 min. Bupropion (10-30 mg/kg) produced acute locomotor hyperactivity compared to Unpaired controls. After repeated administration, there was no progressive increase or decrease in bupropion-induced activity. In a subsequent drug-free session conditioned hyperactivity was observed at 5-30 mg/kg doses. In a follow-up experiment, we examined whether responsiveness to novelty predicted the subsequent unconditioned and conditioned locomotor effect of bupropion. Reactivity to inescapable novelty, novel environment approach, and novel-object interaction were measured before locomotor conditioning with 30 mg/kg bupropion. We replicated the previous experiment, but scores on the novelty screens did not predict locomotor response to bupropion. This study extends the literature by demonstrating that environmental cues repeatedly paired with the stimulant effects of bupropion come to evoke elevated activity in the absence of drug (i.e., conditioned hyperactivity). This finding is consistent with the literature suggesting that bupropion shares many behavioral similarities with other psychomotor stimulants which also produce conditioned hyperactivity. However, a predictive relation between reactivity to forced novelty and the subsequent locomotor effect of bupropion may not be one of these similarities.

  18. Isolation of moulds capable of producing mycotoxins from blue mouldy Tulum cheeses produced in Turkey.

    Science.gov (United States)

    Erdogan, A; Gurses, M; Sert, S

    2003-08-15

    A total of 16 moulds was isolated and identified from 12 blue mouldy Tulum cheeses collected from retailers in Erzurum, Turkey; 12 were Penicillium roqueforti and 4 were Geotrichum candidum. The P. roqueforti isolates were grown in yeast sucrose broth at 5, 12 and 25 degrees C for 10 days, then extracted with chloroform and acetone and the extracts were examined for the presence of patulin, penicillic acid, roquefortine and PR toxin using thin layer chromatography. All of the P. roqueforti strains had toxin-producing ability at 5, 12 and 25 degrees C, eight produced only at 5 and 12 degrees C and six could not produce toxin at 5 degrees C.

  19. Pyrolysis process for producing fuel gas

    Science.gov (United States)

    Serio, Michael A. (Inventor); Kroo, Erik (Inventor); Wojtowicz, Marek A. (Inventor); Suuberg, Eric M. (Inventor)

    2007-01-01

    Solid waste resource recovery in space is effected by pyrolysis processing, to produce light gases as the main products (CH.sub.4, H.sub.2, CO.sub.2, CO, H.sub.2O, NH.sub.3) and a reactive carbon-rich char as the main byproduct. Significant amounts of liquid products are formed under less severe pyrolysis conditions, and are cracked almost completely to gases as the temperature is raised. A primary pyrolysis model for the composite mixture is based on an existing model for whole biomass materials, and an artificial neural network models the changes in gas composition with the severity of pyrolysis conditions.

  20. ECOLOGICAL REGIONALIZATION METHODS OF OIL PRODUCING AREAS

    Directory of Open Access Journals (Sweden)

    Inna Ivanovna Pivovarova

    2017-01-01

    Full Text Available The paper analyses territory zoning methods with varying degrees of anthropogenic pollution risk. The summarized results of spatial analysis of oil pollution of surface water in the most developed oil-producing region of Russia. An example of GIS-zoning according to the degree of environmental hazard is presented. All possible algorithms of cluster analysis are considered for isolation of homogeneous data structures. The conclusion is made on the benefits of using combined methods of analysis for assessing the homogeneity of specific environmental characteristics in selected territories.

  1. Silage produces biofuel for local consumption

    Science.gov (United States)

    2011-01-01

    Background In the normal process of bioethanol production, biomass is transported to integrated large factories for degradation to sugar, fermentation, and recovery of ethanol by distillation. Biomass nutrient loss occurs during preservation and degradation. Our aim was to develop a decentralized ethanol production system appropriate for farm or co-operative level production that uses a solid-state fermentation method for producing bio-ethanol from whole crops, provides cattle feed, and produces no wastes. The idea is to incorporate traditional silage methods with simultaneous saccharification and fermentation. Harvested, fresh biomass is ensiled with biomass-degrading enzymes and yeast. Multiple parallel reactions for biomass degradation and ethanol and lactic acid production are induced in solid culture in hermetically sealed containers at a ranch. After fermentation, ethanol is collected on site from the vapor from heated fermented products. Results The parallel reactions of simultaneous saccharification and fermentation were induced efficiently in the model fermentation system. In a laboratory-scale feasibility study of the process, 250 g of freshly harvested forage rice with 62% moisture was treated with 0.86 filter paper units/g dry matter (DM) of cellulase and 0.32 U/g DM of glucoamylase. After 20 days of incubation at 28°C, 6.4 wt.% of ethanol in fresh matter (equivalent to 169 g/kg DM) was produced. When the 46 wt.% moisture was gathered as vapor from the fermented product, 74% of the produced ethanol was collected. Organic cellular contents (such as the amylase and pronase degradable fractions) were decreased by 63% and organic cell wall (fiber) content by 7% compared to silage prepared from the same material. Conclusions We confirmed that efficient ethanol production is induced in nonsterilized whole rice plants in a laboratory-scale solid-state fermentation system. For practical use of the method, further study is needed to scale-up the fermentation

  2. Producing Knowledge to Reduce Rhetorical Distance

    DEFF Research Database (Denmark)

    Kampf, Constance

    Producing Knowledge to Reduce Rhetorical Distance: Extending Identity and Engaging Mainstream Ideology via the Web Constance Kampf, Department of Research Knowledge Communication, Aarhus School of Business, Denmark McLuhan describes technologies as extensions -the wheel being an extension...... writers a larger public forum into which they can extend their identity. When the identity being extended represents a minority group, the web offers an opportunity for members of that group to engage mainstream ideology and work at reducing the rhetorical distance between their identity and mainstream...... the opportunity for engaging mainstream ideologies in order to reduce the rhetorical distance between minority and majority cultures....

  3. Performance profiles of major energy producers 1994

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-02-01

    Performance Profiles of Major Energy Producers 1994 is the eighteenth annual report of the Energy Information Administration`s (EIA) Financial Reporting System (FRS). The report examines financial and operating developments in energy markets, with particular reference to the 24 major U.S. energy companies required to report annually on Form EIA-28. Financial information is reported by major lines of business, including oil and gas production, petroleum refining and marketing, other energy operations, and nonenergy businesses. Financial and operating results are presented in the context of energy market developments with a view toward identifying changing corporate strategies and measuring the performance of ongoing operations both in the United States and abroad.

  4. High ethanol producing derivatives of Thermoanaerobacter ethanolicus

    Science.gov (United States)

    Ljungdahl, Lars G.; Carriera, Laura H.

    1983-01-01

    Derivatives of the newly discovered microorganism Thermoanaerobacter ethanolicus which under anaerobic and thermophilic conditions continuously ferment substrates such as starch, cellobiose, glucose, xylose and other sugars to produce recoverable amounts of ethanol solving the problem of fermentations yielding low concentrations of ethanol using the parent strain of the microorganism Thermoanaerobacter ethanolicus are disclosed. These new derivatives are ethanol tolerant up to 10% (v/v) ethanol during fermentation. The process includes the use of an aqueous fermentation medium, containing the substrate at a substrate concentration greater than 1% (w/v).

  5. Method for producing metal oxide nanoparticles

    Science.gov (United States)

    Phillips, Jonathan; Mendoza, Daniel; Chen, Chun-Ku

    2008-04-15

    Method for producing metal oxide nanoparticles. The method includes generating an aerosol of solid metallic microparticles, generating plasma with a plasma hot zone at a temperature sufficiently high to vaporize the microparticles into metal vapor, and directing the aerosol into the hot zone of the plasma. The microparticles vaporize in the hot zone into metal vapor. The metal vapor is directed away from the hot zone and into the cooler plasma afterglow where it oxidizes, cools and condenses to form solid metal oxide nanoparticles.

  6. Performance profiles of major energy producers 1989

    Energy Technology Data Exchange (ETDEWEB)

    1991-01-23

    Performance Profiles of Major Energy Producers 1989 is the thirteenth annual report of the Energy Information Administration's (EIA) Financial Reporting System (FRS). The report examines financial and operating developments, with particular reference to the 23 major energy companies (the FRS companies'') required to report annually on Form EIA-28. Financial information is reported by major lines of business including oil and gas production, petroleum refining and marketing, and other energy operations. Domestic and international operations are examined separately in this report. It also traces key developments affecting the financial performance of major energy companies in 1989, as well as review of important trends.

  7. Ambiguity produces attention shifts in category learning.

    Science.gov (United States)

    Vadillo, Miguel A; Orgaz, Cristina; Luque, David; Nelson, James Byron

    2016-04-01

    It has been suggested that people and nonhuman animals protect their knowledge from interference by shifting attention toward the context when presented with information that contradicts their previous beliefs. Despite that suggestion, no studies have directly measured changes in attention while participants are exposed to an interference treatment. In the present experiments, we adapted a dot-probe task to track participants' attention to cues and contexts while they were completing a simple category learning task. The results support the hypothesis that interference produces a change in the allocation of attention to cues and contexts.

  8. Silage produces biofuel for local consumption

    Directory of Open Access Journals (Sweden)

    Kitamoto Hiroko K

    2011-11-01

    Full Text Available Abstract Background In the normal process of bioethanol production, biomass is transported to integrated large factories for degradation to sugar, fermentation, and recovery of ethanol by distillation. Biomass nutrient loss occurs during preservation and degradation. Our aim was to develop a decentralized ethanol production system appropriate for farm or co-operative level production that uses a solid-state fermentation method for producing bio-ethanol from whole crops, provides cattle feed, and produces no wastes. The idea is to incorporate traditional silage methods with simultaneous saccharification and fermentation. Harvested, fresh biomass is ensiled with biomass-degrading enzymes and yeast. Multiple parallel reactions for biomass degradation and ethanol and lactic acid production are induced in solid culture in hermetically sealed containers at a ranch. After fermentation, ethanol is collected on site from the vapor from heated fermented products. Results The parallel reactions of simultaneous saccharification and fermentation were induced efficiently in the model fermentation system. In a laboratory-scale feasibility study of the process, 250 g of freshly harvested forage rice with 62% moisture was treated with 0.86 filter paper units/g dry matter (DM of cellulase and 0.32 U/g DM of glucoamylase. After 20 days of incubation at 28°C, 6.4 wt.% of ethanol in fresh matter (equivalent to 169 g/kg DM was produced. When the 46 wt.% moisture was gathered as vapor from the fermented product, 74% of the produced ethanol was collected. Organic cellular contents (such as the amylase and pronase degradable fractions were decreased by 63% and organic cell wall (fiber content by 7% compared to silage prepared from the same material. Conclusions We confirmed that efficient ethanol production is induced in nonsterilized whole rice plants in a laboratory-scale solid-state fermentation system. For practical use of the method, further study is needed to

  9. Cells and methods for producing fatty alcohols

    Science.gov (United States)

    Pfleger, Brian F.; Youngquist, Tyler J.

    2017-07-18

    Recombinant cells and methods for improved yield of fatty alcohols. The recombinant cells harbor a recombinant thioesterase gene, a recombinant acyl-CoA synthetase gene, and a recombinant acyl-CoA reductase gene. In addition, a gene product from one or more of an acyl-CoA dehydrogenase gene, an enoyl-CoA hydratase gene, a 3-hydroxyacyl-CoA dehydrogenase gene, and a 3-ketoacyl-CoA thiolase gene in the recombinant cells is functionally deleted. Culturing the recombinant cells produces fatty alcohols at high yields.

  10. METHOD AND APPARATUS FOR PRODUCING POWER

    Science.gov (United States)

    Wollan, E.O.

    1961-06-27

    A neutronic reactor comprising two discrete zones; namely, an inner zone containing fissionable material and an outer zone containing fertile material is described. The inner zone is operated at a low temperature and is cooled by pressurized water. The outer zone is operated at a substantially higher temperature and is cooled by steam flashed from the inner zone. The reactor is particularly advantageous in that it produces high temperature steam; yet the materials of construction in the core (inner zone) are not restricted to materials capable of withstanding high temperature operation.

  11. Performance profiles of major energy producers 1989

    Energy Technology Data Exchange (ETDEWEB)

    1991-01-23

    Performance Profiles of Major Energy Producers 1989 is the thirteenth annual report of the Energy Information Administration's (EIA) Financial Reporting System (FRS). The report examines financial and operating developments, with particular reference to the 23 major energy companies (the FRS companies'') required to report annually on Form EIA-28. Financial information is reported by major lines of business including oil and gas production, petroleum refining and marketing, and other energy operations. Domestic and international operations are examined separately in this report. It also traces key developments affecting the financial performance of major energy companies in 1989, as well as review of important trends.

  12. Cardiogenic embolism producing crescendo transient ischemic attacks.

    Science.gov (United States)

    Geraghty, Patrick J; Oak, Jack; Choi, Eric T

    2005-09-01

    Lateralizing, repetitive transient ischemic attacks are characteristic of symptomatic carotid bifurcation atherosclerotic plaques. We report a case in which a cardiogenic embolus, after lodging at the left carotid bifurcation, produced crescendo episodes of expressive aphasia and mild right upper extremity weakness. Complete neurological recovery was achieved following emergent carotid embolectomy and endarterectomy. This case demonstrates that the laminar nature of internal carotid blood flow may result in the localization of embolic events to a single region of the cerebral vasculature, regardless of the source lesion in the carotid artery. The role of endoluminal techniques in the diagnosis and management of such lesions is discussed.

  13. Simon Fraser University Computer Produced Map Catalogue

    Directory of Open Access Journals (Sweden)

    Brian Phillips

    2013-05-01

    Full Text Available An IBM 360/50 computer and magnetic tape are used in a new univer- sity library to produce a map catalogue by area and up to six subiects for each map. Cataloguing is by non-professional staff using the Library of Congress "G, schedule. Author, title, and publisher are in variable length fields, and codes are seldom used for input or interpretation. Ma- chine searches by area, subjects, author, publisher, scale, pro-;ection, date and language can be carried out.

  14. Method for producing thin film electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Narayanan, Manoj; Ma, Beihai; Balachandran, Uthamalingam; Dorris, Stephen

    2016-06-07

    The invention provides for A method for producing pure phase strontium ruthenium oxide films, the method comprising solubilizing ruthenium-containing and strontium-containing compounds to create a mixture; subjecting the mixture to a first temperature above that necessary for forming RuO.sub.2 while simultaneously preventing formation of RuO.sub.2; maintaining the first temperature for a time to remove organic compounds from the mixture, thereby forming a substantially dry film; and subjecting the film to a second temperature for time sufficient to crystallize the film. Also provided is pure phase material comprising strontium ruthenium oxide wherein the material contains no RuO.sub.2.

  15. Method of producing particulate-reinforced composites and composties produced thereby

    Science.gov (United States)

    Han, Qingyou; Liu, Zhiwei

    2013-12-24

    A process for producing particle-reinforced composite materials through utilization of an in situ reaction to produce a uniform dispersion of a fine particulate reinforcement phase. The process includes forming a melt of a first material, and then introducing particles of a second material into the melt and subjecting the melt to high-intenisty acoustic vibration. A chemical reaction initiates between the first and second materials to produce reaction products in the melt. The reaciton products comprise a solide particulate phase, and the high-intensity acoustic vibration fragments and/or separates the reaction products into solid particles that are dispersed in the melt and are smaller than the particles of the second material. Also encompassed are particles-reinforced composite materials produced by such a process.

  16. Method of producing particulate-reinforced composites and composites produced thereby

    Energy Technology Data Exchange (ETDEWEB)

    Han, Qingyou; Liu, Zhiwei

    2015-12-29

    A process for producing particle-reinforced composite materials through utilization of an in situ reaction to produce a uniform dispersion of a fine particulate reinforcement phase. The process includes forming a melt of a first material, and then introducing particles of a second material into the melt and subjecting the melt to high-intensity acoustic vibration. A chemical reaction initiates between the first and second materials to produce reaction products in the melt. The reaction products comprise a solid particulate phase, and the high-intensity acoustic vibration fragments and/or separates the reaction products into solid particles that are dispersed in the melt and are smaller than the particles of the second material. Also encompassed are particle-reinforced composite materials produced by such a process.

  17. CCT`s in a deregulated environment: A producer`s perspective

    Energy Technology Data Exchange (ETDEWEB)

    Edmonds, R.F. Jr.; Fayssoux, J.O. [Duke Power Co., Charlotte, NC (United States)

    1997-12-31

    The US electric industry will be deregulated (or substantially re-regulated) within 5 years. Several states, including California, Rhode Island, and New Hampshire, already have passed legislation to introduce competition into the electric markets before the year 2000. As this trend sweeps across the country, the resulting competitive market for generation will reward the lowest cost producers and force high cost producers out of the market. As a result, at least in the short run, it may be very difficult for new power plants employing Clean Coal Technologies (CCTs) to compete. This paper discusses a producer`s perspective of the new competitive market, and suggests several short and long term strategies and niches for CCTs.

  18. Method of producing particulate-reinforced composites and composites produced thereby

    Science.gov (United States)

    Han, Qingyou; Liu, Zhiwei

    2013-12-24

    A process for producing particle-reinforced composite materials through utilization of an in situ reaction to produce a uniform dispersion of a fine particulate reinforcement phase. The process includes forming a melt of a first material, and then introducing particles of a second material into the melt and subjecting the melt to high-intensity acoustic vibration. A chemical reaction initiates between the first and second materials to produce reaction products in the melt. The reaction products comprise a solid particulate phase, and the high-intensity acoustic vibration fragments and/or separates the reaction products into solid particles that are dispersed in the melt and are smaller than the particles of the second material. Also encompassed are particle-reinforced composite materials produced by such a process.

  19. Water produced with coal-bed methane

    Science.gov (United States)

    ,

    2000-01-01

    Natural gas produced from coal beds (coal-bed methane, CBM) accounts for about 7.5 percent of the total natural gas production in the United States. Along with this gas, water is also brought to the surface. The amount of water produced from most CBM wells is relatively high compared to conventional natural gas wells because coal beds contain many fractures and pores that can contain and transmit large volumes of water. In some areas, coal beds may function as regional or local aquifers and important sources for ground water. The water in coal beds contributes to pressure in the reservoir that keeps methane gas adsorbed to the surface of the coal. This water must be removed by pumping in order to lower the pressure in the reservoir and stimulate desorption of methane from the coal (fi g. 1). Over time, volumes of pumped water typically decrease and the production of gas increases as coal beds near the well bore are dewatered.

  20. Sustainable bioreactor systems for producing hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Zaborsky, O.R.; Radway, J.C.; Yoza, B.A. [Univ. of Hawaii, Honolulu, HI (United States); Benemann, J.R. [Univ. of California, Berkeley, CA (United States). Dept. of Plant and Molecular Biology; Tredici, M.R. [Univ. of Florence (Italy). Dipt. di Scienze e Tecnologie Alimentari e Microbiogiche

    1998-08-01

    The overall goal of Hawaii`s BioHydrogen Program is to generate hydrogen from water using solar energy and microalgae under sustainable conditions. Specific bioprocess engineering objectives include the design, construction, testing and validation of a sustainable photobioreactor system. Specific objectives relating to biology include investigating and optimizing key physiological parameters of cyanobacteria of the genus Arthrospira (Spirulina), the organism selected for initial process development. Another objective is to disseminate the Mitsui-Miami cyanobacteria cultures, now part of the Hawaii Culture Collection (HCC), to other research groups. The approach is to use a single organisms for producing hydrogen gas from water. Key stages are the growth of the biomass, the dark induction of hydrogenase, and the subsequent generation of hydrogen in the light. The biomass production stage involves producing dense cultures of filamentous, non-heterocystous cyanobacteria and optimizing biomass productivity in innovative tubular photobioreactors. The hydrogen generation stages entail inducing the enzymes and metabolic pathways that enable both dark and light-driven hydrogen production. The focus of Year 1 has been on the construction and operation of the outdoor photobioreactor for the production of high-density mass cultures of Arthrospira. The strains in the Mitsui-Miami collection have been organized and distributed to other researchers who are beginning to report interesting results. The project is part of the International Energy Agency`s biohydrogen program.