The Colorado Lightning Mapping Array

NASA Astrophysics Data System (ADS)

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

2012-12-01

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

Plotting Lightning-Stroke Data

NASA Technical Reports Server (NTRS)

Tatom, F. B.; Garst, R. A.

1986-01-01

Data on lightning-stroke locations become easier to correlate with cloudcover maps with aid of new graphical treatment. Geographic region divided by grid into array of cells. Number of lightning strokes in each cell tabulated, and value representing density of lightning strokes assigned to each cell. With contour-plotting routine, computer draws contours of lightning-stroke density for region. Shapes of contours compared directly with shapes of storm cells.

Acoustic localization of triggered lightning

NASA Astrophysics Data System (ADS)

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

2011-05-01

We use acoustic (3.3-500 Hz) arrays to locate local (<20 km) thunder produced by triggered lightning in the Magdalena Mountains of central New Mexico. The locations of the thunder sources are determined by the array back azimuth and the elapsed time since discharge of the lightning flash. We compare the acoustic source locations with those obtained by the Lightning Mapping Array (LMA) from Langmuir Laboratory, which is capable of accurately locating the lightning channels. To estimate the location accuracy of the acoustic array we performed Monte Carlo simulations and measured the distance (nearest neighbors) between acoustic and LMA sources. For close sources (<5 km) the mean nearest-neighbors distance was 185 m compared to 100 m predicted by the Monte Carlo analysis. For far distances (>6 km) the error increases to 800 m for the nearest neighbors and 650 m for the Monte Carlo analysis. This work shows that thunder sources can be accurately located using acoustic signals.

On the VHF Source Retrieval Errors Associated with Lightning Mapping Arrays (LMAs)

NASA Technical Reports Server (NTRS)

Koshak, W.

2016-01-01

This presentation examines in detail the standard retrieval method: that of retrieving the (x, y, z, t) parameters of a lightning VHF point source from multiple ground-based Lightning Mapping Array (LMA) time-of-arrival (TOA) observations. The solution is found by minimizing a chi-squared function via the Levenberg-Marquardt algorithm. The associated forward problem is examined to illustrate the importance of signal-to-noise ratio (SNR). Monte Carlo simulated retrievals are used to assess the benefits of changing various LMA network properties. A generalized retrieval method is also introduced that, in addition to TOA data, uses LMA electric field amplitude measurements to retrieve a transient VHF dipole moment source.

Correlated Lightning Mapping Array (LMA) and Radar Observations of the Initial Stages of Florida Triggered Lightning Discharges

NASA Technical Reports Server (NTRS)

Hill, J. D.; Pilkey, J.; Uman, M, A.; Jordan, D. M.; Biggerstaff, M. I.; Rison, W.; Blakeslee, R.

2012-01-01

We characterize the geometrical and electrical characteristics of the initial stages of nine Florida triggered lightning discharges using a Lightning Mapping Array (LMA), a C-band SMART radar, and measured channel-base currents. We determine initial channel and subsequent branch lengths, average initial channel and branch propagation speeds, and channel-base current at the time of each branch initiation. The channel-base current is found to not change significantly when branching occurs, an unexpected result. The initial stage of Florida triggered lightning typically transitions from vertical to horizontal propagation at altitudes of 3-6 km, near the typical 0 C level of 4-5 km and several kilometers below the expected center of the negative cloud-charge region at 7-8 km. The data presented potentially provide information on thunderstorm electrical and hydrometeor structure and discharge propagation physics. LMA source locations were obtained from VHF sources of positive impulsive currents as small as 10 A, in contrast to expectations found in the literature.

Characteristics of Lightning Within Electrified Snowfall Events Using Lightning Mapping Arrays

NASA Astrophysics Data System (ADS)

Schultz, Christopher J.; Lang, Timothy J.; Bruning, Eric C.; Calhoun, Kristin M.; Harkema, Sebastian; Curtis, Nathan

2018-02-01

This study examined 34 lightning flashes within four separate thundersnow events derived from lightning mapping arrays (LMAs) in northern Alabama, central Oklahoma, and Washington DC. The goals were to characterize the in-cloud component of each lightning flash, as well as the correspondence between the LMA observations and lightning data taken from national lightning networks like the National Lightning Detection Network (NLDN). Individual flashes were examined in detail to highlight several observations within the data set. The study results demonstrated that the structures of these flashes were primarily normal polarity. The mean area encompassed by this set of flashes is 375 km2, with a maximum flash extent of 2,300 km2, a minimum of 3 km2, and a median of 128 km2. An average of 2.29 NLDN flashes were recorded per LMA-derived lightning flash. A maximum of 11 NLDN flashes were recorded in association with a single LMA-derived flash on 10 January 2011. Additionally, seven of the 34 flashes in the study contain zero NLDN-identified flashes. Eleven of the 34 flashes initiated from tall human-made objects (e.g., communication towers). In at least six lightning flashes, the NLDN detected a return stroke from the cloud back to the tower and not the initial upward leader. This study also discusses lightning's interaction with the human-built environment and provides an example of lightning within heavy snowfall observed by Geostationary Operational Environmental Satellite-16's Geostationary Lightning Mapper.

Characteristics of Lightning within Electrified Snowfall Events using Lightning Mapping Arrays.

PubMed

Schultz, Christopher J; Lang, Timothy J; Bruning, Eric C; Calhoun, Kristin M; Harkema, Sebastian; Curtis, Nathan

2018-02-27

This study examined 34 lightning flashes within four separate thundersnow events derived from lightning mapping arrays (LMAs) in northern Alabama, central Oklahoma, and Washington DC. The goals were to characterize the in-cloud component of each lightning flash, as well as the correspondence between the LMA observations and lightning data taken from national lightning networks like the National Lightning Detection Network (NLDN). Individual flashes were examined in detail to highlight several observations within the dataset. The study results demonstrated that the structures of these flashes were primarily normal polarity. The mean area encompassed by this set of flashes is 375 km 2 , with a maximum flash extent of 2300 km 2 , a minimum of 3 km 2 , and a median of 128 km 2 . An average of 2.29 NLDN flashes were recorded per LMA-derived lightning flash. A maximum of 11 NLDN flashes were recorded in association with a single LMA-derived flash on 10 January 2011. Additionally, seven of the 34 flashes in the study contain zero NLDN identified flashes. Eleven of the 34 flashes initiated from tall human-made objects (e.g., communication towers). In at least six lightning flashes, the NLDN detected a return stroke from the cloud back to the tower and not the initial upward leader. This study also discusses lightning's interaction with the human built environment and provides an example of lightning within heavy snowfall observed by GOES-16's Geostationary Lightning Mapper.

Lightning Location Using Acoustic Signals

NASA Astrophysics Data System (ADS)

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

2013-05-01

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

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

NASA Technical Reports Server (NTRS)

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

2013-01-01

A 12 station Lightning Mapping Array (LMA) network was deployed during October 2011in the vicinity of São Paulo, Brazil (SP-LMA) to contribute total lightning measurements to an international field campaign [CHUVA - Cloud processes of tHe main precipitation systems in Brazil: A contribUtion to cloud resolVing modeling and to the GPM (GlobAl Precipitation Measurement)]. The SP-LMA was operational from November 2011 through March 2012. Sensor spacing was on the order of 15-30 km, with a network diameter on the order of 40-50km. The SP-LMA provides good 3-D lightning mapping out to150 km from the network center, with 2-D coverage considerably farther. In addition to supporting CHUVA science/mission objectives, the SP-LMA is supporting the generation of unique proxy data for the Geostationary Lightning Mapper (GLM) and Advanced Baseline Imager (ABI), on NOAA's Geostationary Operational Environmental Satellite-R (GOES-R: scheduled for a 2015 launch). These proxy data will be used to develop and validate operational algorithms so that they will be ready to use on "day1" following the GOES-R launch. The SP-LMA data also will be intercompared with lightning observations from other deployed lightning networks to advance our understanding of the capabilities/contributions of each of these networks toward GLM proxy and validation activities. This paper addresses the network assessment and analyses for intercomparison studies and GOES-R proxy activities

The Lightning Nitrogen Oxides Model (LNOM): Status and Recent Applications

NASA Technical Reports Server (NTRS)

Koshak, William; Khan, Maudood; Peterson, Harold

2011-01-01

Improvements to the NASA Marshall Space Flight Center Lightning Nitrogen Oxides Model (LNOM) are discussed. Recent results from an August 2006 run of the Community Multiscale Air Quality (CMAQ) modeling system that employs LNOM lightning NOx (= NO + NO2) estimates are provided. The LNOM analyzes Lightning Mapping Array (LMA) data to estimate the raw (i.e., unmixed and otherwise environmentally unmodified) vertical profile of lightning NOx. The latest LNOM estimates of (a) lightning channel length distributions, (b) lightning 1-m segment altitude distributions, and (c) the vertical profile of NOx are presented. The impact of including LNOM-estimates of lightning NOx on CMAQ output is discussed.

Do cosmic ray air showers initiate lightning?: A statistical analysis of cosmic ray air showers and lightning mapping array data

NASA Astrophysics Data System (ADS)

Hare, B. M.; Dwyer, J. R.; Winner, L. H.; Uman, M. A.; Jordan, D. M.; Kotovsky, D. A.; Caicedo, J. A.; Wilkes, R. A.; Carvalho, F. L.; Pilkey, J. T.; Ngin, T. K.; Gamerota, W. R.; Rassoul, H. K.

2017-08-01

It has been argued in the technical literature, and widely reported in the popular press, that cosmic ray air showers (CRASs) can initiate lightning via a mechanism known as relativistic runaway electron avalanche (RREA), where large numbers of high-energy and low-energy electrons can, somehow, cause the local atmosphere in a thundercloud to transition to a conducting state. In response to this claim, other researchers have published simulations showing that the electron density produced by RREA is far too small to be able to affect the conductivity in the cloud sufficiently to initiate lightning. In this paper, we compare 74 days of cosmic ray air shower data collected in north central Florida during 2013-2015, the recorded CRASs having primary energies on the order of 1016 eV to 1018 eV and zenith angles less than 38°, with Lightning Mapping Array (LMA) data, and we show that there is no evidence that the detected cosmic ray air showers initiated lightning. Furthermore, we show that the average probability of any of our detected cosmic ray air showers to initiate a lightning flash can be no more than 5%. If all lightning flashes were initiated by cosmic ray air showers, then about 1.6% of detected CRASs would initiate lightning; therefore, we do not have enough data to exclude the possibility that lightning flashes could be initiated by cosmic ray air showers.

An Overview of LANL's New Hurricane Lightning Project (Invited)

NASA Astrophysics Data System (ADS)

Jeffery, C. A.; Shao, X.; Reisner, J.; Kao, C. J.; Brockwell, M.; Chylek, P.; Fierro, A.; Galassi, M.; Godinez, H. C.; Guimond, S.; Hamlin, T.; Henderson, B. G.; Ho, C.; Holden, D.; Light, T. E.; O'Connor, N.; Suszcynsky, D. M.

2009-12-01

For the last two years, Los Alamos National Laboratory has sponsored an internal hurricane lightning project with four main goals: (1) To develop and deploy a new dual VLF/VHF lightning mapping array in the Mississippi River Delta south of New Orleans. (2) To develop a new hurricane forecast capability with fully prognostic cloud electrification and lightning discharge physics, based on a model framework developed at Oklahoma University. (3) To develop a new data assimilation approach for ingesting LANL lightning data into our forecast model that exploits the phenomenological relationship between lightning occurrence and intense convection. (4) To demonstrate that the assimilation of lightning data from the new LANL Gulf array into the hurricane forecast model improves the prediction of rapid intensification (RI), when RI is driven by eyewall adjustment (axisymmetrization) triggered by intense convective events (hot towers). In this talk, I present an overview of LANL's new hurricane lighting project, and the progress we have made to-date in achieving the project's four main goals.

Location and analysis of acoustic infrasound pulses in lightning

NASA Astrophysics Data System (ADS)

Arechiga, R.; Stock, M.; Thomas, R.; Erives, H.; Rison, W.; Edens, H.; Lapierre, J.

2014-07-01

Acoustic, VHF, and electrostatic measurements throw new light onto the origin and production mechanism of the thunder infrasound signature (<10 Hz) from lightning. This signature, composed of an initial compression followed by a rarefaction pulse, has been the subject of several unconfirmed theories and models. The observations of two intracloud flashes which each produced multiple infrasound pulses were analyzed for this work. Once the variation of the speed of sound with temperature is taken into account, both the compression and rarefaction portions of the infrasound pulses are found to originate very near lightning channels mapped by the Lightning Mapping Array. We found that none of the currently proposed models can explain infrasound generation by lightning, and thus propose an alternate theory: The infrasound compression pulse is produced by electrostatic interaction of the charge deposited on the channel and in the streamer zone of the lightning channel.

Infrasound Observations from Lightning

NASA Astrophysics Data System (ADS)

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

2008-12-01

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

A first look at lightning energy determined from GLM

NASA Astrophysics Data System (ADS)

Bitzer, P. M.; Burchfield, J. C.; Brunner, K. N.

2017-12-01

The Geostationary Lightning Mapper (GLM) was launched in November 2016 onboard GOES-16 has been undergoing post launch and product post launch testing. While these have typically focused on lightning metrics such as detection efficiency, false alarm rate, and location accuracy, there are other attributes of the lightning discharge that are provided by GLM data. Namely, the optical energy radiated by lightning may provide information useful for lightning physics and the relationship of lightning energy to severe weather development. This work presents initial estimates of the lightning optical energy detected by GLM during this initial testing, with a focus on observations during field campaign during spring 2017 in Huntsville. This region is advantageous for the comparison due to the proliferation of ground-based lightning instrumentation, including a lightning mapping array, interferometer, HAMMA (an array of electric field change meters), high speed video cameras, and several long range VLF networks. In addition, the field campaign included airborne observations of the optical emission and electric field changes. The initial estimates will be compared with previous observations using TRMM-LIS. In addition, a comparison between the operational and scientific GLM data sets will also be discussed.

Tennessee Valley Total and Cloud-to-Ground Lightning Climatology Comparison

NASA Technical Reports Server (NTRS)

Buechler, Dennis; Blakeslee, R. J.; Hall, J. M.; McCaul, E. W.

2008-01-01

The North Alabama Lightning Mapping Array (NALMA) has been in operation since 2001 and consists often VHF receivers deployed across northern Alabama. The NALMA locates sources of impulsive VHF radio signals from total lightning by accurately measuring the time that the signals arrive at the different receiving stations. The sources detected are then clustered into flashes by applying spatially and temporally constraints. This study examines the total lightning climatology of the region derived from NALMA and compares it to the cloud-to-ground (CG) climatology derived from the National Lightning Detection Network (NLDN) The presentation compares the total and CG lightning trends for monthly, daily, and hourly periods.

A WRF-Chem Analysis of Flash Rates, Lightning-NOx Production and Subsequent Trace Gas Chemistry of the 29-30 May 2012 Convective Event in Oklahoma During DC3

NASA Technical Reports Server (NTRS)

Cummings, Kristin A.; Pickering, Kenneth; Barth, Mary; Weinheimer, A.; Bela, M.; Li, Y; Allen, D.; Bruning, E.; MacGorman, D.; Rutledge, S.;

The NASA Lightning Nitrogen Oxides Model (LNOM): Recent Updates and Applications

NASA Technical Reports Server (NTRS)

Koshak, William; Peterson, Harold; Biazar, Arastoo; Khan, Maudood; Wang, Lihua; Park, Yee-Hun

2011-01-01

Improvements to the NASA Marshall Space Flight Center Lightning Nitrogen Oxides Model (LNOM) and its application to the Community Multiscale Air Quality (CMAQ) modeling system are presented. The LNOM analyzes Lightning Mapping Array (LMA) and National Lightning Detection Network(tm) (NLDN) data to estimate the raw (i.e., unmixed and otherwise environmentally unmodified) vertical profile of lightning NOx (= NO + NO2). Lightning channel length distributions and lightning 10-m segment altitude distributions are also provided. In addition to NOx production from lightning return strokes, the LNOM now includes non-return stroke lightning NOx production due to: hot core stepped and dart leaders, stepped leader corona sheath, K-changes, continuing currents, and M-components. The impact of including LNOM-estimates of lightning NOx for an August 2006 run of CMAQ is discussed.

Triangulations of sprites relative to parent lighting near the Oklahoma Lightning Mapping Array

NASA Astrophysics Data System (ADS)

Lu, G.; Cummer, S. A.; Li, J.; Lyons, W. A.; Stanley, M. A.; Krehbiel, P. R.; Rison, W.; Thomas, R. J.; Weiss, S. A.; Beasley, W. H.; Bruning, E. C.; MacGorman, D. R.; Palivec, K.; Samaras, T. M.

2012-12-01

Temporal and spatial development of sprite-producing lightning flashes is examined with coordinated observations over an asymmetric mesoscale convective system on June 29, 2011 near the Oklahoma Lightning Mapping Array (OK-LMA). About 30 sprites were mutually observed from Bennett, Colorado and Hawley, Texas, allowing us to triangulate sprite formation in comparison with spatial/temporal development of the parent lightning. Complementary measurements of broadband (<1 Hz to ~300 kHz) radio frequency lightning signals are available from several magnetic sensors across the United States. Our analyses indicate that although sprite locations can be significantly offset horizontally (up to 70 km) from the parent ground stroke, they are usually laterally within 30 km of the in-cloud lightning activity during the 100 ms time interval prior to the sprite production. This is true for short-delayed sprites produced within 20 ms after a causative stroke, and long-delayed sprites appearing up to more than 200 ms after the stroke. Multiple sprites appearing as dancing/jumping events can be produced during one single flash either in a single lightning channel, through series of current surges superposed on a long and intense continuing current, or in multiple lightning channels through distinct ground strokes of the flash. The burst of continuous very-low-frequency/low-frequency lightning sferics commonly observed in association with sprites is linked to the horizontal progression of multiple negative leaders through positive charged regions of the cloud, which are typically centered at altitudes ~1-2 km (or more) above the freezing level.

Mathematical Inversion of Lightning Data: Techniques and Applications

NASA Technical Reports Server (NTRS)

Koshak, William

2003-01-01

A survey of some interesting mathematical inversion studies dealing with radio, optical, and electrostatic measurements of lightning are presented. A discussion of why NASA is interested in lightning, what specific physical properties of lightning are retrieved, and what mathematical techniques are used to perform the retrievals are discussed. In particular, a relatively new multi-station VHF time-of-arrival (TOA) antenna network is now on-line in Northern Alabama and will be discussed. The network, called the Lightning Mapping Array (LMA), employs GPS timing and detects VHF radiation from discrete segments (effectively point emitters) that comprise the channel of lightning strokes within cloud and ground flashes. The LMA supports on-going ground-validation activities of the low Earth orbiting Lightning Imaging Sensor (LIS) satellite developed at NASA Marshall Space Flight Center (MSFC) in Huntsville, Alabama. The LMA also provides detailed studies of the distribution and evolution of thunderstorms and lightning in the Tennessee Valley, and offers interesting comparisons with other meteorological/geophysical datasets. In order to take full advantage of these benefits, it is essential that the LMA channel mapping accuracy (in both space and time) be fully characterized and optimized. A new channel mapping retrieval algorithm is introduced for this purpose. To characterize the spatial distribution of retrieval errors, the algorithm has been applied to analyze literally tens of millions of computer-simulated lightning VHF point sources that have been placed at various ranges, azimuths, and altitudes relative to the LMA network. Statistical results are conveniently summarized in high-resolution, color-coded, error maps.

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

NASA Technical Reports Server (NTRS)

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

2014-01-01

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

Monitoring the development of volcanic eruptions through volcanic lightning - Using a lightning mapping array, seismic and infrasound array, and visual plume analysis

NASA Astrophysics Data System (ADS)

Smith, C. M.; Thompson, G.; McNutt, S. R.; Behnke, S. A.; Edens, H. E.; Van Eaton, A. R.; Gaudin, D.; Thomas, R. J.

2017-12-01

The period of 28 May - 7 June 2015 at Sakurajima Volcano, Japan witnessed a multitude of Vulcanian eruptive events, which resulted in plumes reaching 500-3000m above the vent. These plumes varied from white, gas-rich plumes to dark grey and black ash-rich plumes, and were recorded on lowlight and infrared cameras. A nine-station lightning mapping array (LMA) was deployed to locate sources of VHF (67-73 MHz) radiation produced by lightning flashes and other types of electrical activity such as `continuous RF (radio frequency)'. Two Nanometrics Trillium broadband seismometers and six BSU infrasound sensors were deployed. Over this ten day period we recorded 1556 events that consisted of both seismic and infrasound signals, indicating explosive activity. There are an additional 1222 events that were recorded as only seismic or infrasound signals, which may be a result of precursory seismic signals or noise contamination. Plume discharge types included both distinct lightning flashes and `continuous RF'. The LMA ran continuously for the duration of the experiment. On 30 May 2015 at least seven lightning flashes were also detected by the Vaisala Global Lightning Detection 360 network, which detects VLF (3-30 kHz) radiation. However the University of Washington's World Wide Lightning Location Network, which also detects VLF radiation, detected no volcanic lightning flashes in this time period. This indicates that the electrical activity in Sakurajima's plume occurs near the lower limits of the VLF detection threshold. We investigate relationships between the plume dynamics, the geophysical signal and the corresponding electrical activity through: plume velocity and height; event waveform cross-correlation; volcano acoustic-seismic ratios; overall geophysical energy; RSAM records; and VHF sources detected by the LMA. By investigating these relationships we hope to determine the seismic/infrasound energy threshold required to generate measurable electrical activity. Seismic and infrasound are two of the most common volcanic monitoring methods. By developing the relationships between plume electrification and these geophysical methods we hope to expand the use of lightning for active volcano monitoring.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Henderson, Bradley G; Suszcynsky, David M; Hamlin, Timothy E

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

Acoustic Network Localization and Interpretation of Infrasonic Pulses from Lightning

NASA Astrophysics Data System (ADS)

Arechiga, R. O.; Johnson, J. B.; Badillo, E.; Michnovicz, J. C.; Thomas, R. J.; Edens, H. E.; Rison, W.

2011-12-01

We improve on the localization accuracy of thunder sources and identify infrasonic pulses that are correlated across a network of acoustic arrays. We attribute these pulses to electrostatic charge relaxation (collapse of the electric field) and attempt to model their spatial extent and acoustic source strength. Toward this objective we have developed a single audio range (20-15,000 Hz) acoustic array and a 4-station network of broadband (0.01-500 Hz) microphone arrays with aperture of ~45 m. The network has an aperture of 1700 m and was installed during the summers of 2009-2011 in the Magdalena mountains of New Mexico, an area that is subject to frequent lightning activity. We are exploring a new technique based on inverse theory that integrates information from the audio range and the network of broadband acoustic arrays to locate thunder sources more accurately than can be achieved with a single array. We evaluate the performance of the technique by comparing the location of thunder sources with RF sources located by the lightning mapping array (LMA) of Langmuir Laboratory at New Mexico Tech. We will show results of this technique for lightning flashes that occurred in the vicinity of our network of acoustic arrays and over the LMA. We will use acoustic network detection of infrasonic pulses together with LMA data and electric field measurements to estimate the spatial distribution of the charge (within the cloud) that is used to produce a lightning flash, and will try to quantify volumetric charges (charge magnitude) within clouds.

The NASA Lightning Nitrogen Oxides Model (LNOM): Application to Air Quality Modeling

NASA Technical Reports Server (NTRS)

Koshak, William; Peterson, Harold; Khan, Maudood; Biazar, Arastoo; Wang, Lihua

2011-01-01

Recent improvements to the NASA Marshall Space Flight Center Lightning Nitrogen Oxides Model (LNOM) and its application to the Community Multiscale Air Quality (CMAQ) modeling system are discussed. The LNOM analyzes Lightning Mapping Array (LMA) and National Lightning Detection Network(TradeMark)(NLDN) data to estimate the raw (i.e., unmixed and otherwise environmentally unmodified) vertical profile of lightning NO(x) (= NO + NO2). The latest LNOM estimates of lightning channel length distributions, lightning 1-m segment altitude distributions, and the vertical profile of lightning NO(x) are presented. The primary improvement to the LNOM is the inclusion of non-return stroke lightning NOx production due to: (1) hot core stepped and dart leaders, (2) stepped leader corona sheath, K-changes, continuing currents, and M-components. The impact of including LNOM-estimates of lightning NO(x) for an August 2006 run of CMAQ is discussed.

Error Analyses of the North Alabama Lightning Mapping Array (LMA)

NASA Technical Reports Server (NTRS)

Koshak, W. J.; Solokiewicz, R. J.; Blakeslee, R. J.; Goodman, S. J.; Christian, H. J.; Hall, J. M.; Bailey, J. C.; Krider, E. P.; Bateman, M. G.; Boccippio, D. J.

2003-01-01

Two approaches are used to characterize how accurately the North Alabama Lightning Mapping Array (LMA) is able to locate lightning VHF sources in space and in time. The first method uses a Monte Carlo computer simulation to estimate source retrieval errors. The simulation applies a VHF source retrieval algorithm that was recently developed at the NASA-MSFC and that is similar, but not identical to, the standard New Mexico Tech retrieval algorithm. The second method uses a purely theoretical technique (i.e., chi-squared Curvature Matrix theory) to estimate retrieval errors. Both methods assume that the LMA system has an overall rms timing error of 50ns, but all other possible errors (e.g., multiple sources per retrieval attempt) are neglected. The detailed spatial distributions of retrieval errors are provided. Given that the two methods are completely independent of one another, it is shown that they provide remarkably similar results, except that the chi-squared theory produces larger altitude error estimates than the (more realistic) Monte Carlo simulation.

The Kinematic and Microphysical Control of Storm Integrated Lightning Flash Extent

NASA Technical Reports Server (NTRS)

Carey, Lawrence D.; Peterson, Harold S.; Schultz, Elise V.; Matthee, Retha; Schultz, Christopher J.; Petersen, Walter A,; Bain, Lamont

2012-01-01

Objective: To investigate the kinematic and microphysical control of lightning properties, particularly those that may govern the production of nitrogen oxides (NOx) in thunderstorms, such as flash rate, type (intracloud [IC] vs. cloud-to-ground [CG] ) and extent. Data and Methodology: a) NASA MSFC Lightning Nitrogen Oxides Model (LNOM) is applied to North Alabama Lightning Mapping Array (NALMA) and Vaisala National Lightning Detection Network(TradeMark) (NLDN) observations following ordinary convective cells through their lifecycle. b) LNOM provides estimates of flash type, channel length distributions, lightning segment altitude distributions (SADs) and lightning NOx production profiles (Koshak et al. 2012). c) LNOM lightning characteristics are compared to the evolution of updraft and precipitation properties inferred from dual-Doppler (DD) and polarimetric radar analyses of UAHuntsville Advanced Radar for Meteorological and Operational Research (ARMOR, Cband, polarimetric) and KHTX (S-band, Doppler).

Lightning: Nature's Probe of Severe Weather for Research and Operations

NASA Technical Reports Server (NTRS)

Blakeslee, R.J.

2007-01-01

Lightning, the energetic and broadband electrical discharge produced by thunderstorms, provides a natural remote sensing signal for the study of severe storms and related phenomena on global, regional and local scales. Using this strong signal- one of nature's own probes of severe weather -lightning measurements prove to be straightforward and take advantage of a variety of measurement techniques that have advanced considerably in recent years. We briefly review some of the leading lightning detection systems including satellite-based optical detectors such as the Lightning Imaging Sensor, and ground-based radio frequency systems such as Vaisala's National Lightning Detection Network (NLDN), long range lightning detection systems, and the Lightning Mapping Array (LMA) networks. In addition, we examine some of the exciting new research results and operational capabilities (e.g., shortened tornado warning lead times) derived from these observations. Finally we look forward to the next measurement advance - lightning observations from geostationary orbit.

VHF lightning mapping observations of a triggered lightning flash

NASA Astrophysics Data System (ADS)

Edens, H. E.; Eack, K. B.; Eastvedt, E. M.; Trueblood, J. J.; Winn, W. P.; Krehbiel, P. R.; Aulich, G. D.; Hunyady, S. J.; Murray, W. C.; Rison, W.; Behnke, S. A.; Thomas, R. J.

2012-10-01

On 3 August 2010 an extensive lightning flash was triggered over Langmuir Laboratory in New Mexico. The upward positive leader propagated into the storm's midlevel negative charge region, extending over a horizontal area of 13 × 13 km and 7.5 km altitude. The storm had a normal-polarity tripolar charge structure with upper positive charge over midlevel negative charge. Lightning Mapping Array (LMA) observations were used to estimate positive leader velocities along various branches, which were in the range of 1-3 × 104 m s-1, slower than in other studies. The upward positive leader initiated at 3.4 km altitude, but was mapped only above 4.0 km altitude after the onset of retrograde negative breakdown, indicating a change in leader propagation and VHF emissions. The observations suggest that both positive and negative breakdown produce VHF emissions that can be located by time-of-arrival systems, and that not all VHF emissions occurring along positive leader channels are associated with retrograde negative breakdown.

Mapping thunder sources by inverting acoustic and electromagnetic observations

NASA Astrophysics Data System (ADS)

Anderson, J. F.; Johnson, J. B.; Arechiga, R. O.; Thomas, R. J.

2014-12-01

We present a new method of locating current flow in lightning strikes by inversion of thunder recordings constrained by Lightning Mapping Array observations. First, radio frequency (RF) pulses are connected to reconstruct conductive channels created by leaders. Then, acoustic signals that would be produced by current flow through each channel are forward modeled. The recorded thunder is considered to consist of a weighted superposition of these acoustic signals. We calculate the posterior distribution of acoustic source energy for each channel with a Markov Chain Monte Carlo inversion that fits power envelopes of modeled and recorded thunder; these results show which parts of the flash carry current and produce thunder. We examine the effects of RF pulse location imprecision and atmospheric winds on quality of results and apply this method to several lightning flashes over the Magdalena Mountains in New Mexico, USA. This method will enable more detailed study of lightning phenomena by allowing researchers to map current flow in addition to leader propagation.

High-Resolution WRF Forecasts of Lightning Threat

NASA Technical Reports Server (NTRS)

Goodman, S. J.; McCaul, E. W., Jr.; LaCasse, K.

2007-01-01

Tropical Rainfall Measuring Mission (TRMM)lightning and precipitation observations have confirmed the existence of a robust relationship between lightning flash rates and the amount of large precipitating ice hydrometeors in storms. This relationship is exploited, in conjunction with the capabilities of the Weather Research and Forecast (WRF) model, to forecast the threat of lightning from convective storms using the output fields from the model forecasts. The simulated vertical flux of graupel at -15C is used in this study as a proxy for charge separation processes and their associated lightning risk. Initial experiments using 6-h simulations are conducted for a number of case studies for which three-dimensional lightning validation data from the North Alabama Lightning Mapping Array are available. The WRF has been initialized on a 2 km grid using Eta boundary conditions, Doppler radar radial velocity and reflectivity fields, and METAR and ACARS data. An array of subjective and objective statistical metrics is employed to document the utility of the WRF forecasts. The simulation results are also compared to other more traditional means of forecasting convective storms, such as those based on inspection of the convective available potential energy field.

Sao Paulo Lightning Mapping Array (SP-LMA): Deployment and Plans

NASA Technical Reports Server (NTRS)

Bailey, J. C.; Carey, L. D.; Blakeslee, R. J.; Albrecht, R.; Morales, C. A.; Pinto, O., Jr.

2011-01-01

An 8-10 station Lightning Mapping Array (LMA) network is being deployed in the vicinity of Sao Paulo to create the SP-LMA for total lightning measurements in association with the international CHUVA [Cloud processes of tHe main precipitation systems in Brazil: A contribUtion to cloud resolVing modeling and to the GPM (GlobAl Precipitation Measurement)] field campaign. Besides supporting CHUVA science/mission objectives and the Sao Luz Paraitinga intensive operation period (IOP) in December 2011-January 2012, the SP-LMA will support the generation of unique proxy data for the Geostationary Lightning Mapper (GLM) and Advanced Baseline Imager (ABI), both sensors on the NOAA Geostationary Operational Environmental Satellite-R (GOES-R), presently under development and scheduled for a 2015 launch. The proxy data will be used to develop and validate operational algorithms so that they will be ready for use on "day1" following the launch of GOES-R. A preliminary survey of potential sites in the vicinity of Sao Paulo was conducted in December 2009 and January 2010, followed up by a detailed survey in July 2010, with initial network deployment scheduled for October 2010. However, due to a delay in the Sa Luz Paraitinga IOP, the SP-LMA will now be installed in July 2011 and operated for one year. Spacing between stations is on the order of 15-30 km, with the network "diameter" being on the order of 30-40 km, which provides good 3-D lightning mapping 150 km from the network center. Optionally, 1-3 additional stations may be deployed in the vicinity of Sa Jos dos Campos.

Sao Paulo Lightning Mapping Array (SP-LMA): Deployment, Operation and Initial Data Analysis

NASA Technical Reports Server (NTRS)

Blakeslee, R.; Bailey, J. C.; Carey, L. D.; Rudlosky, S.; Goodman, S. J.; Albrecht, R.; Morales, C. A.; Anseimo, E. M.; Pinto, O.

2012-01-01

An 8-10 station Lightning Mapping Array (LMA) network is being deployed in the vicinity of Sao Paulo to create the SP-LMA for total lightning measurements in association with the international CHUVA [Cloud processes of the main precipitation systems in Brazil: A contribution to cloud resolving modeling and to the GPM (Global Precipitation Measurement)] field campaign. Besides supporting CHUVA science/mission objectives and the Sao Luiz do Paraitinga intensive operation period (IOP) in November-December 2011, the SP-LMA will support the generation of unique proxy data for the Geostationary Lightning Mapper (GLM) and Advanced Baseline Imager (ABI), both sensors on the NOAA Geostationary Operational Environmental Satellite-R (GOES-R), presently under development and scheduled for a 2015 launch. The proxy data will be used to develop and validate operational algorithms so that they will be ready for use on "day1" following the launch of GOES-R. A preliminary survey of potential sites in the vicinity of Sao Paulo was conducted in December 2009 and January 2010, followed up by a detailed survey in July 2010, with initial network deployment scheduled for October 2010. However, due to a delay in the Sao Luiz do Paraitinga IOP, the SP-LMA will now be installed in July 2011 and operated for one year. Spacing between stations is on the order of 15-30 km, with the network "diameter" being on the order of 30-40 km, which provides good 3-D lightning mapping 150 km from the network center. Optionally, 1-3 additional stations may be deployed in the vicinity of Sao Jos dos Campos.

A Lightning Channel Retrieval Algorithm for the North Alabama Lightning Mapping Array (LMA)

NASA Technical Reports Server (NTRS)

Koshak, William; Arnold, James E. (Technical Monitor)

2002-01-01

A new multi-station VHF time-of-arrival (TOA) antenna network is, at the time of this writing, coming on-line in Northern Alabama. The network, called the Lightning Mapping Array (LMA), employs GPS timing and detects VHF radiation from discrete segments (effectively point emitters) that comprise the channel of lightning strokes within cloud and ground flashes. The network will support on-going ground validation activities of the low Earth orbiting Lightning Imaging Sensor (LIS) satellite developed at NASA Marshall Space Flight Center (MSFC) in Huntsville, Alabama. It will also provide for many interesting and detailed studies of the distribution and evolution of thunderstorms and lightning in the Tennessee Valley, and will offer many interesting comparisons with other meteorological/geophysical wets associated with lightning and thunderstorms. In order to take full advantage of these benefits, it is essential that the LMA channel mapping accuracy (in both space and time) be fully characterized and optimized. In this study, a new revised channel mapping retrieval algorithm is introduced. The algorithm is an extension of earlier work provided in Koshak and Solakiewicz (1996) in the analysis of the NASA Kennedy Space Center (KSC) Lightning Detection and Ranging (LDAR) system. As in the 1996 study, direct algebraic solutions are obtained by inverting a simple linear system of equations, thereby making computer searches through a multi-dimensional parameter domain of a Chi-Squared function unnecessary. However, the new algorithm is developed completely in spherical Earth-centered coordinates (longitude, latitude, altitude), rather than in the (x, y, z) cartesian coordinates employed in the 1996 study. Hence, no mathematical transformations from (x, y, z) into spherical coordinates are required (such transformations involve more numerical error propagation, more computer program coding, and slightly more CPU computing time). The new algorithm also has a more realistic definition of source altitude that accounts for Earth oblateness (this can become important for sources that are hundreds of kilometers away from the network). In addition, the new algorithm is being applied to analyze computer simulated LMA datasets in order to obtain detailed location/time retrieval error maps for sources in and around the LMA network. These maps will provide a more comprehensive analysis of retrieval errors for LMA than the 1996 study did of LDAR retrieval errors. Finally, we note that the new algorithm can be applied to LDAR, and essentially any other multi-station TWA network that depends on direct line-of-site antenna excitation.

The North Alabama Lightning Mapping Array (LMA): A Network Overview

NASA Technical Reports Server (NTRS)

Blakeslee, R. J.; Bailey, J.; Buechler, D.; Goodman, S. J.; McCaul, E. W., Jr.; Hall, J.

2005-01-01

The North Alabama Lightning Mapping Array (LMA) is s a 3-D VHF regional lightning detection system that provides on-orbit algorithm validation and instrument performance assessments for the NASA Lightning Imaging Sensor, as well as information on storm kinematics and updraft evolution that offers the potential to improve severe storm warning lead time by up t o 50% and decrease te false alarm r a t e ( for non-tornado producing storms). In support of this latter function, the LMA serves 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. The LMA, which became operational i n November 2001, consists of VHF receivers deployed across northern Alabama and a base station located at the National Space Science and Technology Center (NSSTC), which is on t h e campus of the University of Alabama in Huntsville. The LMA system locates the sources of impulsive VHF radio signals s from lightning by accurately measuring the time that the signals aririve at the different receiving stations. Each station's records the magnitude and time of the peak lightning radiation signal in successive 80 ms intervals within a local unused television channel (channel 5, 76-82 MHz in our case ) . Typically hundreds of sources per flash can be reconstructed, which i n t u r n produces accurate 3-dimensional lightning image maps (nominally <50 m error within 150 la. range). The data are transmitted back t o a base station using 2.4 GHz wireless Ethernet data links and directional parabolic grid antennas. There are four repeaters in the network topology and the links have an effective data throughput rate ranging from 600 kbits s -1 t o 1.5 %its s -1. This presentation provides an overview of t h e North Alabama network, the data processing (both real-time and post processing) and network statistics.

Colorado Lightning Mapping Array Collaborations through the GOES-R Visiting Scientist Program

NASA Technical Reports Server (NTRS)

Stano, Geoffrey T.; Szoke, Edward; Rydell, Nezette; Cox, Robert; Mazur, Rebecca

2014-01-01

For the past two years, the GOES-R Proving Ground has solicited proposals for its Visiting Scientist Program. NASA's Short-term Prediction Research and Transition (SPoRT) Center has used this opportunity to support the GOES-R Proving Ground by expanding SPoRT's total lightning collaborations. In 2012, this expanded the evaluation of SPoRT's pseudo-geostationary lightning mapper product to the Aviation Weather Center and Storm Prediction Center. This year, SPoRT has collaborated with the Colorado Lightning Mapping Array (COLMA) and potential end users. In particular, SPoRT is collaborating with the Cooperative Institute for Research in the Atmosphere (CIRA) and Colorado State University (CSU) to obtain these data in real-time. From there, SPoRT is supporting the transition of these data to the local forecast offices in Boulder, Colorado and Cheyenne, Wyoming as well as to Proving Ground projects (e.g., the Hazardous Weather Testbed's Spring Program and Aviation Weather Center's Summer Experiment). This presentation will focus on the results of this particular Visiting Scientist Program trip. In particular, the COLMA data are being provided to both forecast offices for initial familiarization. Additionally, several forecast issues have been highlighted as important uses for COLMA data in the operational environment. These include the utility of these data for fire weather situations, situational awareness for both severe weather and lightning safety, and formal evaluations to take place in the spring of 2014.

Future Expansion of the Lightning Surveillance System at the Kennedy Space Center and the Cape Canaveral Air Force Station, Florida, USA

NASA Technical Reports Server (NTRS)

Mata, C. T.; Wilson, J. G.

2012-01-01

The NASA Kennedy Space Center (KSC) and the Air Force Eastern Range (ER) use data from two cloud-to-ground (CG) lightning detection networks, the Cloud-to-Ground Lightning Surveillance System (CGLSS) and the U.S. National Lightning Detection Network (NLDN), and a volumetric mapping array, the lightning detection and ranging II (LDAR II) system: These systems are used to monitor and characterize lightning that is potentially hazardous to launch or ground operations and hardware. These systems are not perfect and both have documented missed lightning events when compared to the existing lightning surveillance system at Launch Complex 39B (LC39B). Because of this finding it is NASA's plan to install a lightning surveillance system around each of the active launch pads sharing site locations and triggering capabilities when possible. This paper shows how the existing lightning surveillance system at LC39B has performed in 2011 as well as the plan for the expansion around all active pads.

Learning from concurrent Lightning Imaging Sensor and Lightning Mapping Array observations in preparation for the MTG-LI mission

NASA Astrophysics Data System (ADS)

Defer, Eric; Bovalo, Christophe; Coquillat, Sylvain; Pinty, Jean-Pierre; Farges, Thomas; Krehbiel, Paul; Rison, William

2016-04-01

The upcoming decade will see the deployment and the operation of French, European and American space-based missions dedicated to the detection and the characterization of the lightning activity on Earth. For instance the Tool for the Analysis of Radiation from lightNIng and Sprites (TARANIS) mission, with an expected launch in 2018, is a CNES mission dedicated to the study of impulsive energy transfers between the atmosphere of the Earth and the space environment. It will carry a package of Micro Cameras and Photometers (MCP) to detect and locate lightning flashes and triggered Transient Luminous Events (TLEs). At the European level, the Meteosat Third Generation Imager (MTG-I) satellites will carry in 2019 the Lightning Imager (LI) aimed at detecting and locating the lightning activity over almost the full disk of Earth as usually observed with Meteosat geostationary infrared/visible imagers. The American community plans to operate a similar instrument on the GOES-R mission for an effective operation in early 2016. In addition NASA will install in 2016 on the International Space Station the spare version of the Lightning Imaging Sensor (LIS) that has proved its capability to optically detect the tropical lightning activity from the Tropical Rainfall Measuring Mission (TRMM) spacecraft. We will present concurrent observations recorded by the optical space-borne Lightning Imaging Sensor (LIS) and the ground-based Very High Frequency (VHF) Lightning Mapping Array (LMA) for different types of lightning flashes. The properties of the cloud environment will also be considered in the analysis thanks to coincident observations of the different TRMM cloud sensors. The characteristics of the optical signal will be discussed according to the nature of the parent flash components and the cloud properties. This study should provide some insights not only on the expected optical signal that will be recorded by LI, but also on the definition of the validation strategy of LI, and on the synergetic use of LI and ground-based VHF mappers like the SAETTA LMA network in Corsica for operational and research activities. Acknowledgements: this study is part of the SOLID-PREVALS project and is supported by CNES-TOSCA.

Use of High-resolution WRF Simulations to Forecast Lightning Threat

NASA Technical Reports Server (NTRS)

McCaul, William E.; LaCasse, K.; Goodman, S. J.

2006-01-01

Recent observational studies have confirmed the existence of a robust statistical relationship between lightning flash rates and the amount of large precipitating ice hydrometeors in storms. This relationship is exploited, in conjunction with the capabilities of recent forecast models such as WRF, to forecast the threat of lightning from convective storms using the output fields from the model forecasts. The simulated vertical flux of graupel at -15C is used in this study as a proxy for charge separation processes and their associated lightning risk. Six-h simulations are conducted for a number of case studies for which three-dimensional lightning validation data from the North Alabama Lightning Mapping Array are available. Experiments indicate that initialization of the WRF model on a 2 km grid using Eta boundary conditions, Doppler radar radial velocity and reflectivity fields, and METAR and ACARS data yield the most realistic simulations. An array of subjective and objective statistical metrics are employed to document the utility of the WRF forecasts. The simulation results are also compared to other more traditional means of forecasting convective storms, such as those based on inspection of the convective available potential energy field.

Lightning spectra at 100,000 fps

NASA Astrophysics Data System (ADS)

McHarg, M. G.; Harley, J.; Haaland, R. K.; Edens, H. E.; Stenbaek-Nielsen, H.

2016-12-01

A fundamental understanding of lightning can be inferred from the spectral emissions resulting from the leader and return stroke channel. We examine an event recorded at 00:58:07 on 19 July 2015 at Langmuir Laboratory. We recorded lightning spectra using a 100 line per mm grating in front of a Phantom V2010 camera with an 85mm Nikon lens recording at 100,000 frames per second. Coarse resolution spectra (approximately 5nm resolution) are produced from approximately 400 nm to 800 nm for each frame. Electric field data from the Langmuir Electric Field Array for the 03:19:19 event show 10 V/m changes in the electric field associated with multiple return strokes visible in the spectral data. We used the spectral data to compare temperatures at the top, middle and bottom of the lightning channel. Lightning Mapping Array data at Langmuir for the 00:58:07 event show a complex flash extending 10 km in the East-West plane and 6 km in the North-South plane. The imagery data imply that this is a bolt-from-the-blue event.

North Alabama Lightning Mapping Array (LMA): VHF Source Retrieval Algorithm and Error Analyses

NASA Technical Reports Server (NTRS)

Koshak, W. J.; Solakiewicz, R. J.; Blakeslee, R. J.; Goodman, S. J.; Christian, H. J.; Hall, J.; Bailey, J.; Krider, E. P.; Bateman, M. G.; Boccippio, D.

2003-01-01

Two approaches are used to characterize how accurately the North Alabama Lightning Mapping Array (LMA) is able to locate lightning VHF sources in space and in time. The first method uses a Monte Carlo computer simulation to estimate source retrieval errors. The simulation applies a VHF source retrieval algorithm that was recently developed at the NASA Marshall Space Flight Center (MSFC) and that is similar, but not identical to, the standard New Mexico Tech retrieval algorithm. The second method uses a purely theoretical technique (i.e., chi-squared Curvature Matrix Theory) to estimate retrieval errors. Both methods assume that the LMA system has an overall rms timing error of 50 ns, but all other possible errors (e.g., multiple sources per retrieval attempt) are neglected. The detailed spatial distributions of retrieval errors are provided. Given that the two methods are completely independent of one another, it is shown that they provide remarkably similar results. However, for many source locations, the Curvature Matrix Theory produces larger altitude error estimates than the (more realistic) Monte Carlo simulation.

A Summary of the NASA Lightning Nitrogen Oxides Model (LNOM) and Recent Results

NASA Technical Reports Server (NTRS)

Koshak, William; Peterson, Harld

2011-01-01

The NASA Marshall Space Flight Center introduced the Lightning Nitrogen Oxides Model (LNOM) a couple of years ago to combine routine state-of-the-art measurements of lightning with empirical laboratory results of lightning NOx production. The routine measurements included VHF lightning source data [such as from the North Alabama Lightning Mapping Array (LMA)], and ground flash location, peak current, and stroke multiplicity data from the National Lightning Detection Network(TradeMark) (NLDN). Following these initial runs of LNOM, the model was updated to include several non-return stroke lightning NOx production mechanisms, and provided the impact of lightning NOx on an August 2006 run of CMAQ. In this study, we review the evolution of the LNOM in greater detail and discuss the model?s latest upgrades and applications. Whereas previous applications were limited to five summer months of data for North Alabama thunderstorms, the most recent LNOM analyses cover several years. The latest statistics of ground and cloud flash NOx production are provided.

Lightning NOx Statistics Derived by NASA Lightning Nitrogen Oxides Model (LNOM) Data Analyses

NASA Technical Reports Server (NTRS)

Koshak, William; Peterson, Harold

2013-01-01

What is the LNOM? The NASA Marshall Space Flight Center (MSFC) Lightning Nitrogen Oxides Model (LNOM) [Koshak et al., 2009, 2010, 2011; Koshak and Peterson 2011, 2013] analyzes VHF Lightning Mapping Array (LMA) and National Lightning Detection Network(TradeMark) (NLDN) data to estimate the lightning nitrogen oxides (LNOx) produced by individual flashes. Figure 1 provides an overview of LNOM functionality. Benefits of LNOM: (1) Does away with unrealistic "vertical stick" lightning channel models for estimating LNOx; (2) Uses ground-based VHF data that maps out the true channel in space and time to < 100 m accuracy; (3) Therefore, true channel segment height (ambient air density) is used to compute LNOx; (4) True channel length is used! (typically tens of kilometers since channel has many branches and "wiggles"); (5) Distinction between ground and cloud flashes are made; (6) For ground flashes, actual peak current from NLDN used to compute NOx from lightning return stroke; (7) NOx computed for several other lightning discharge processes (based on Cooray et al., 2009 theory): (a) Hot core of stepped leaders and dart leaders, (b) Corona sheath of stepped leader, (c) K-change, (d) Continuing Currents, and (e) M-components; and (8) LNOM statistics (see later) can be used to parameterize LNOx production for regional air quality models (like CMAQ), and for global chemical transport models (like GEOS-Chem).

Acoustic vs Interferometric Measurements of Lightning

NASA Astrophysics Data System (ADS)

Arechiga, R. O.; Erives, H.; Sonnenfeld, R. G.; Stanley, M. A.; Rison, W.; Thomas, R. J.; Edens, H. E.; Lapierre, J. L.; Stock, M.; Jensen, D.; Morris, K.

2015-12-01

During the summer of 2015 we acquired acoustic and RF data on severalflashes from thunderstorms over Fort Morgan CO. and Langmuir Laboratoryin the Magdalena mountains of central New Mexico. The acoustic arrayswere located at a distance of roughly 150 m from the interferometers.Lightning mapping array and slow antenna data were also obtained. Theacoustic arrays consist of arrays of five audio-range and six infrasoundmicrophones operating at 50 KHz and 1 KHz respectively. The lightninginterferometer at Fort Morgan CO. consists of three flat-plate, 13" diameterantennas at the vertices of an equilateral 50 m per side triangle. Theinterferometer at Langmuir Laboratory consists of three 13" dishes separatedby about 15 m. Both interferometers, operating at 180 Megasamples persecond, use the analysis software and digitizer hardware pioneered byStanley, Stock et al. The high data rate allows for excellent spatialresolution of high speed (and typically high current) processes such asK-changes, return strokes and dart-leaders. In previous studies, we haveshown the usefulness of acoustic recordings to locate thunder sources aswell as infrasound pulses from lightning. This work will present acomparison of Acoustic and Interferometric measurements from lightning,using some interesting flashes, including a positive cloud to ground,that occurred in these campaigns.

Measurements of Ozone, Lightning, and Electric Fields within Thunderstorms over Langmuir Laboratory, New Mexico

NASA Astrophysics Data System (ADS)

Eack, K. B.; Winn, W. P.; Rust, W. D.; Minschwaner, K.; Fredrickson, S.; Kennedy, D.; Edens, H. E.; Kalnajs, L. E.; Rabin, R. M.; Lu, G. P.; Bonin, D.

2008-12-01

A field project was conducted at the Langmuir Laboratory for Atmospheric Research during the summer of 2008 in an effort to better understand the direct production of ozone within electrically active storms. Five balloon flights were successfully launched into thunderstorms during this project. In situ measurements from the balloon instrument package included ozone mixing ratio, electric field strength, meteorological variables, and GPS location and timing. Lightning discharges were identified within each storm using a ground based lightning mapping array. The data show that the instruments ascended through regions of high electric fields within the sampled storms, and in some cases the balloon was in very close proximity to lightning. Relationships between electric field, lightning, and ozone observed during these flights will be discussed.

Analysis of ELF Radio Atmospherics Radiated by Rocket-Triggered Lightning

NASA Astrophysics Data System (ADS)

Dupree, N. A.; Moore, R. C.; Pilkey, J. T.; Uman, M. A.; Jordan, D. M.; Caicedo, J. A.; Hare, B.; Ngin, T. K.

2014-12-01

Experimental observations of ELF radio atmospherics produced by rocket-triggered lightning flashes are used to analyze Earth-ionosphere waveguide excitation and propagation characteristics. Rocket-triggered lightning experiments are performed at the International Center for Lightning Research and Testing (ICLRT) located at Camp Blanding, Florida. Long-distance ELF observations are performed in California, Greenland, and Antarctica. The lightning current waveforms directly measured at the base of the lightning channel (at the ICLRT) along with pertinent Lightning Mapping Array (LMA) data are used together with the Long Wavelength Propagation Capability (LWPC) code to predict the radio atmospheric (sferic) waveform observed at the receiver locations under various ionospheric conditions. We identify fitted exponential electron density profiles that accurately describe the observed propagation delays, phase delays, and signal amplitudes. The ability to infer ionospheric characteristics using distant ELF observations greatly enhances ionospheric remote sensing capabilities, especially in regard to interpreting observations of transient luminous events (TLEs) and other ionospheric effects associated with lightning.

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

NASA Technical Reports Server (NTRS)

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

2015-01-01

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

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

NASA Technical Reports Server (NTRS)

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

2004-01-01

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

Acoustic Location of Lightning Using Interferometric Techniques

NASA Astrophysics Data System (ADS)

Erives, H.; Arechiga, R. O.; Stock, M.; Lapierre, J. L.; Edens, H. E.; Stringer, A.; Rison, W.; Thomas, R. J.

2013-12-01

Acoustic arrays have been used to accurately locate thunder sources in lightning flashes. The acoustic arrays located around the Magdalena mountains of central New Mexico produce locations which compare quite well with source locations provided by the New Mexico Tech Lightning Mapping Array. These arrays utilize 3 outer microphones surrounding a 4th microphone located at the center, The location is computed by band-passing the signal to remove noise, and then computing the cross correlating the outer 3 microphones with respect the center reference microphone. While this method works very well, it works best on signals with high signal to noise ratios; weaker signals are not as well located. Therefore, methods are being explored to improve the location accuracy and detection efficiency of the acoustic location systems. The signal received by acoustic arrays is strikingly similar to th signal received by radio frequency interferometers. Both acoustic location systems and radio frequency interferometers make coherent measurements of a signal arriving at a number of closely spaced antennas. And both acoustic and interferometric systems then correlate these signals between pairs of receivers to determine the direction to the source of the received signal. The primary difference between the two systems is the velocity of propagation of the emission, which is much slower for sound. Therefore, the same frequency based techniques that have been used quite successfully with radio interferometers should be applicable to acoustic based measurements as well. The results presented here are comparisons between the location results obtained with current cross correlation method and techniques developed for radio frequency interferometers applied to acoustic signals. The data were obtained during the summer 2013 storm season using multiple arrays sensitive to both infrasonic frequency and audio frequency acoustic emissions from lightning. Preliminary results show that interferometric techniques have good potential for improving the lightning location accuracy and detection efficiency of acoustic arrays.

An Integrated 0-1 Hour First-Flash Lightning Nowcasting, Lightning Amount and Lightning Jump Warning Capability

NASA Technical Reports Server (NTRS)

Mecikalski, John; Jewett, Chris; Carey, Larry; Zavodsky, Brad; Stano, Geoffrey; Chronis, Themis

2015-01-01

Using satellite-based methods that provide accurate 0-1 hour convective initiation (CI) nowcasts, and rely on proven success coupling satellite and radar fields in the Corridor Integrated Weather System (CIWS; operated and developed at MIT-Lincoln Laboratory), to subsequently monitor for first-flash lightning initiation (LI) and later period lightning trends as storms evolve. Enhance IR-based methods within the GOES-R CI Algorithm (that must meet specific thresholds for a given cumulus cloud before the cloud is considered to have an increased likelihood of producing lightning next 90 min) that forecast LI. Integrate GOES-R CI and LI fields with radar thresholds (e.g., first greater than or equal to 40 dBZ echo at the -10 C altitude) and NWP model data within the WDSS-II system for LI-events from new convective storms. Track ongoing lightning using Lightning Mapping Array (LMA) and pseudo-Geostationary Lightning Mapper (GLM) data to assess per-storm lightning trends (e.g., as tied to lightning jumps) and outline threat regions. Evaluate the ability to produce LI nowcasts through a "lightning threat" product, and obtain feedback from National Weather Service forecasters on its value as a decision support tool.

Use of Vertically Integrated Ice in WRF-Based Forecasts of Lightning Threat

NASA Technical Reports Server (NTRS)

McCaul, E. W., jr.; Goodman, S. J.

2008-01-01

Previously reported methods of forecasting lightning threat using fields of graupel flux from WRF simulations are extended to include the simulated field of vertically integrated ice within storms. Although the ice integral shows less temporal variability than graupel flux, it provides more areal coverage, and can thus be used to create a lightning forecast that better matches the areal coverage of the lightning threat found in observations of flash extent density. A blended lightning forecast threat can be constructed that retains much of the desirable temporal sensitivity of the graupel flux method, while also incorporating the coverage benefits of the ice integral method. The graupel flux and ice integral fields contributing to the blended forecast are calibrated against observed lightning flash origin density data, based on Lightning Mapping Array observations from a series of case studies chosen to cover a wide range of flash rate conditions. Linear curve fits that pass through the origin are found to be statistically robust for the calibration procedures.

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

NASA Technical Reports Server (NTRS)

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.

Weather, Climate, and Society: New Demands on Science and Services

NASA Technical Reports Server (NTRS)

2010-01-01

A new algorithm has been constructed to estimate the path length of lightning channels for the purpose of improving the model predictions of lightning NOx in both regional air quality and global chemistry/climate models. This algorithm was tested and applied to VHF signals detected by the North Alabama Lightning Mapping Array (NALMA). The accuracy of the algorithm was characterized by comparing algorithm output to the plots of individual discharges whose lengths were computed by hand. Several thousands of lightning flashes within 120 km of the NALMA network centroid were gathered from all four seasons, and were analyzed by the algorithm. The mean, standard deviation, and median statistics were obtained for all the flashes, the ground flashes, and the cloud flashes. Channel length distributions were also obtained for the different seasons.

Energy and Power Spectra of Thunder in the Magdalena Mountains, Central New Mexico

NASA Astrophysics Data System (ADS)

Johnson, R. L.; Johnson, J. B.; Arechiga, R. O.; Michnovicz, J. C.; Edens, H. E.; Rison, W.

2011-12-01

Thunder is generated primarily by heating and expansion of the atmosphere around a lightning channel and by charge relaxation within a cloud. Broadband acoustic studies are important for inferring dynamic charge behavior during and after lightning events. During the Summer monsoon seasons of 2009-2011, we deployed networks of 3-5 stations consisting of broadband (0.01 to 500 Hz) acoustic arrays and audio microphones in the Magdalena Mountains in central New Mexico. We utilize Lightning Mapping Array (LMA) data for accurate timing of lightning events within a 10 km radius of our network. Unlike the LMA, which detects VHF signals from breakdown processes, thunder signals may be used to observe charge dynamics and thermal shocking of the atmosphere. Previous investigations show that thunder spectral content may distinguish between electrostatic and thermal heating processes. We collected extensive datasets in terms of number of independent broadband sensors (up to 20), number of observed flashes (hundreds from multiple storms), and available coincident LMA data. We use infrasound and audio data to quantify total acoustic energy produced at lightning sources in various frequency bands. We attribute the spectral content and intensity of thunder signals to source characteristics, sensor locations, propagation effects, and noise. We observe variations in acoustic energy for both entire storm systems and individual lightning flashes. We propose that some variations may be related to the type of lightning flash and that spectral content is important for distinguishing between thunder generation mechanisms.

Investigation of the infrasound produced by geophysical events such as volcanoes, thunder, and avalanches: the case for local infrasound monitoring (Invited)

NASA Astrophysics Data System (ADS)

Johnson, J. B.; Marcillo, O. E.; Arechiga, R. O.; Johnson, R.; Edens, H. E.; Marshall, H.; Havens, S.; Waite, G. P.

2010-12-01

Volcanoes, lightning, and mass wasting events generate substantial infrasonic energy that propagates for long distances through the atmosphere with generally low intrinsic attenuation. Although such sources are often studied with regional infrasound arrays that provide important records of their occurrence, position, and relative magnitudes these signals recorded at tens to hundreds of kilometers are often significantly affected by propagation effects. Complex atmospheric structure, due to heterogeneous winds and temperatures, and intervening topography can be responsible for multi-pathing, signal attenuation, and focusing or, alternatively, information loss (i.e., a shadow zone). At far offsets, geometric spreading diminishes signal amplitude requiring low noise recording sites and high fidelity microphones. In contrast recorded excess pressures at local distances are much higher in amplitude and waveforms are more representative of source phenomena. We report on recent studies of volcanoes, thunder, and avalanches made with networks and arrays of infrasound sensors deployed local (within a few km) to the source. At Kilauea Volcano (Hawaii) we deployed a network of ~50 infrasound sensitive sensors (flat from 50 s to 50 Hz) to track the coherence of persistent infrasonic tremor signals in the near-field (out to a few tens of kilometers). During periods of high winds (> 5-10 m/s) we found significant atmospheric influence for signals recorded at stations only a few kilometers from the source. Such observations have encouraged us to conduct a range of volcano, thunder, and snow avalanche studies with networks of small infrasound arrays (~30 m aperture) deployed close to the source region. We present results from local microphone deployments (12 sensors) at Santiaguito Volcano (Guatemala) where we are able to precisely (~10 m resolution) locate acoustic sources from explosions and rock falls. We also present results from our thunder mapping acoustic arrays (15 sensors) in the Magdalena Mountains of New Mexico capable of mapping lightning channels more than 10 km in extent whose positions are corroborated by the radio wave detecting lightning mapping array. We also discuss the recent implementation of a network of snow avalanche detection arrays (12 sensors) in Idaho that are used to monitor and track and map infrasound produced by moving sources. We contend that local infrasound deployment is analogous to local seismic monitoring in that it enables precision localization and interpretation of source phenomena.

An Algorithm for Obtaining the Distribution of 1-Meter Lightning Channel Segment Altitudes for Application in Lightning NOx Production Estimation

NASA Technical Reports Server (NTRS)

Peterson, Harold; Koshak, William J.

2009-01-01

An algorithm has been developed to estimate the altitude distribution of one-meter lightning channel segments. The algorithm is required as part of a broader objective that involves improving the lightning NOx emission inventories of both regional air quality and global chemistry/climate models. The algorithm was tested and applied to VHF signals detected by the North Alabama Lightning Mapping Array (NALMA). The accuracy of the algorithm was characterized by comparing algorithm output to the plots of individual discharges whose lengths were computed by hand; VHF source amplitude thresholding and smoothing were applied to optimize results. Several thousands of lightning flashes within 120 km of the NALMA network centroid were gathered from all four seasons, and were analyzed by the algorithm. The mean, standard deviation, and median statistics were obtained for all the flashes, the ground flashes, and the cloud flashes. One-meter channel segment altitude distributions were also obtained for the different seasons.

The Goes-R Geostationary Lightning Mapper (GLM): Algorithm and Instrument Status

NASA Technical Reports Server (NTRS)

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

2010-01-01

The Geostationary Operational Environmental Satellite (GOES-R) is the next series to follow the existing GOES system currently operating over the Western Hemisphere. Superior spacecraft and instrument technology will support expanded detection of environmental phenomena, resulting in more timely and accurate forecasts and warnings. Advancements over current GOES capabilities include a new capability for total lightning detection (cloud and cloud-to-ground flashes) from the Geostationary Lightning Mapper (GLM), and improved capability for the Advanced Baseline Imager (ABI). The Geostationary Lighting Mapper (GLM) will map total lightning activity (in-cloud and cloud-to-ground lighting flashes) continuously day and night with near-uniform spatial resolution of 8 km with a product refresh rate of less than 20 sec over the Americas and adjacent oceanic regions. This will aid in forecasting severe storms and tornado activity, and convective weather impacts on aviation safety and efficiency. In parallel with the instrument development (a prototype and 4 flight models), a GOES-R Risk Reduction Team and Algorithm Working Group Lightning Applications Team have begun to develop the Level 2 algorithms, cal/val performance monitoring tools, and new applications. Proxy total lightning data from the NASA Lightning Imaging Sensor on the Tropical Rainfall Measuring Mission (TRMM) satellite and regional test beds are being used to develop the pre-launch algorithms and applications, and also improve our knowledge of thunderstorm initiation and evolution. A joint field campaign with Brazilian researchers in 2010-2011 will produce concurrent observations from a VHF lightning mapping array, Meteosat multi-band imagery, Tropical Rainfall Measuring Mission (TRMM) Lightning Imaging Sensor (LIS) overpasses, and related ground and in-situ lightning and meteorological measurements in the vicinity of Sao Paulo. These data will provide a new comprehensive proxy data set for algorithm and application development.

Geostationary Lightning Mapper for GOES-R

NASA Technical Reports Server (NTRS)

Goodman, Steven; Blakeslee, Richard; Koshak, William

2007-01-01

The Geostationary Lightning Mapper (GLM) is a single channel, near-IR optical detector, used to detect, locate and measure total lightning activity over the full-disk as part of a 3-axis stabilized, geostationary weather satellite system. The next generation NOAA Geostationary Operational Environmental Satellite (GOES-R) series with a planned launch in 2014 will carry a GLM that will provide continuous day and night observations of lightning from the west coast of Africa (GOES-E) to New Zealand (GOES-W) when the constellation is fully operational. The mission objectives for the GLM are to 1) provide continuous, full-disk lightning measurements for storm warning and Nowcasting, 2) provide early warning of tornadic activity, and 3) accumulate a long-term database to track decadal changes of lightning. The GLM owes its heritage to the NASA Lightning Imaging Sensor (1997-Present) and the Optical Transient Detector (1995-2000), which were developed for the Earth Observing System and have produced a combined 11 year data record of global lightning activity. Instrument formulation studies begun in January 2006 will be completed in March 2007, with implementation expected to begin in September 2007. Proxy total lightning data from the NASA Lightning Imaging Sensor on the Tropical Rainfall Measuring Mission (TRMM) satellite, airborne science missions (e.g., African Monsoon Multi-disciplinary Analysis, AMMA), and regional test beds (e.g, Lightning Mapping Arrays) are being used to develop the pre-launch algorithms and applications, and also improve our knowledge of thunderstorm initiation and evolution. Real time lightning mapping data now being provided to selected forecast offices will lead to improved understanding of the application of these data in the severe storm warning process and accelerate the development of the pre-launch algorithms and Nowcasting applications. Proxy data combined with MODIS and Meteosat Second Generation SEVERI observations will also lead to new applications (e.g., multi-sensor precipitation algorithms blending the GLM with the Advanced Baseline Imager, convective cloud initiation and identification, early warnings of lightning threat, storm tracking, and data assimilation).

Geostationary Lightning Mapper for GOES-R and Beyond

NASA Technical Reports Server (NTRS)

Goodman, Steven J.; Blakeslee, R. J.; Koshak, W.

2008-01-01

The Geostationary Lightning Mapper (GLM) is a single channel, near-IR imager/optical transient event detector, used to detect, locate and measure total lightning activity over the full-disk as part of a 3-axis stabilized, geostationary weather satellite system. The next generation NOAA Geostationary Operational Environmental Satellite (GOES-R) series with a planned launch readiness in December 2014 will carry a GLM that will provide continuous day and night observations of lightning from the west coast of Africa (GOES-E) to New Zealand (GOES-W) when the constellation is fUlly operational. The mission objectives for the GLM are to 1) provide continuous, full-disk lightning measurements for storm warning and nowcasting, 2) provide early warning of tornadic activity, and 3) accumulate a long-term database to track decadal changes of lightning. The GLM owes its heritage to the NASA Lightning Imaging Sensor (1997-Present) and the Optical Transient Detector (1995-2000), which were developed for the Earth Observing System and have produced a combined 13 year data record of global lightning activity. Instrument formulation studies were completed in March 2007 and the implementation phase to develop a prototype model and up to four flight models will be underway in the latter part of 2007. In parallel with the instrument development, a GOES-R Risk Reduction Team and Algorithm Working Group Lightning Applications Team have begun to develop the Level 2 algorithms and applications. Proxy total lightning data from the NASA Lightning Imaging Sensor on the Tropical Rainfall Measuring Mission (TRMM) satellite and regional test beds (e.g., Lightning Mapping Arrays in North Alabama and the Washington DC Metropolitan area) are being used to develop the pre-launch algorithms and applications, and also improve our knowledge of thunderstorm initiation and evolution. Real time lightning mapping data are being provided in an experimental mode to selected National Weather Service (NWS) forecast offices in Southern and Eastern Region. This effort is designed to help improve our understanding of the application of these data in operational settings.

Electrical and Hydrometeor Structure of Thunderstorms that produce Upward Lightning

NASA Astrophysics Data System (ADS)

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

2017-12-01

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

Analysis and Modeling of Trace Gases and Aerosols in Severe Convection: The 22 June 2012 DC3 Case

NASA Astrophysics Data System (ADS)

Barth, M. C.; Apel, E. C.; Bela, M.; Fried, A.; Fuchs, B.; Pickering, K. E.; Pollack, I. B.; Rutledge, S. A.

2016-12-01

The Deep Convective Clouds and Chemistry (DC3) field campaign aimed to quantify and characterize the dynamics, physics, lightning, and transport of trace gases and aerosols in convection, as well as the chemical aging of convective outflow plumes in the upper troposphere. These goals were met by deploying radars, lightning mapping arrays, weather balloons, and aircraft to sample storms in northeast Colorado, west Texas to central Oklahoma, and northern Alabama. Here, we use one case, 22 June 2012 severe convection in northeast Colorado and southwest Nebraska, as an example for quantifying and predicting convective transport of trace gases and aerosols, lightning flash rate, lightning production of nitrogen oxides, and subsequent ozone production downwind of the storms. This case was unique in that one severe storm ingested a wildfire smoke plume at 7 km altitude while other storms in the area did not. Several analyses of this case have been done using the aircraft composition measurements, dual-Doppler and polarimetric radar products, and lightning mapping array data. It was determined that the storm unaffected by the High Park fire smoke plume had a 4.8±0.9%/km entrainment rate and estimated scavenging efficiencies of CH2O, H2O2, CH3OOH, SO2, and HNO3 of 41±4%, 79±19, 44±47%, 92±4%, 95±12%, respectively. Total (intracloud and cloud-to-ground) lightning flash rates were 98-106 flashes per minute when the aircraft were sampling the outflow of the storms, resulting in an estimate of lightning-NOx production of 142±25 moles NO per flash. Box modeling simulations estimate the production of O3 in the convective outflow of these storms to be 11-14 ppbv over 2 days. These results are used to evaluate the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) to learn how well a state-of-the-art model represents the storm processing of trace gases. The WRF-Chem simulations are analyzed further to examine the effect of aerosols in the smoke plume on the storm characteristics, including precipitation, convective transport, lightning flash rate, and lightning-NOx production.

Total Lightning Observations within Electrified Snowfall using Polarimetric Radar, LMA, and NLDN Measurements

NASA Technical Reports Server (NTRS)

Schultz, Christopher J.; Carey, Lawerence D.; Brunning, Eric C.; Blakeslee, Richard

2013-01-01

Four electrified snowfall cases are examined using total lightning measurements from lightning mapping arrays (LMAs), and the National Lightning Detection Network (NLDN) from Huntsville, AL and Washington D.C. In each of these events, electrical activity was in conjunction with heavy snowfall rates, sometimes exceeding 5-8 cm hr-1. A combination of LMA, and NLDN data also indicate that many of these flashes initiated from tall communications towers and traveled over large horizontal distances. During events near Huntsville, AL, the Advanced Radar for Meteorological and Operational Research (ARMOR) C-band polarimetric radar was collecting range height indicators (RHIs) through regions of heavy snowfall. The combination of ARMOR polarimetric radar and VHF LMA observations suggested contiguous layer changes in height between sloping aggregate-dominated layers and horizontally-oriented crystals. These layers may have provided ideal conditions for the development of extensive regions of charge and resultant horizontal propagation of the lightning flashes over large distances.

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

NASA Technical Reports Server (NTRS)

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.

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

NASA Astrophysics Data System (ADS)

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

2007-12-01

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

Ground- and Space-based Observations of Horizontally-extensive Lightning Flashes

NASA Astrophysics Data System (ADS)

Zhang, D.; Cummins, K. L.; Bitzer, P. M.

2017-12-01

Horizontally-extensive lightning flashes occur frequently in association with mature and late phases of multicellular thunderstorms, both in trailing stratiform regions and horizontally-extensive anvils. The spatial relationship between these flashes and the parent cloud volume is of importance for space launch operational decision making, and is of broader scientific interest. Before this question can be accurately addressed, there is a need to understand the degree to which current lightning observation systems can depict the spatial extent of these long flashes. In this ongoing work, we will intercompare the depiction of horizontally-extensive flashes using several ground-based lightning locating systems (LLSs) located at Kennedy Space Center (KSC) with space-based observations observed by the recently-launched Geostationary Lightning Mapper (GLM) onboard the GOES-16 satellite. Ground-based datasets include the KSC Lightning Mapping Array (KSCLMA), the operational narrowband digital interferometer network MERLIN, and the combined cloud-to-ground and cloud lightning dataset produced by the U.S. National Lightning Detection Network (NLDN). The KSCLMA system is a network of VHF time-of-arrival sensors that preferentially report breakdown processes, and MERLIN is a network of VHF interferometers that point to the discharges in the horizontal plane. Observations to date indicate that MERLIN and the KSCSLMA provide similar overall descriptions of the spatial and temporal extent of these flashes, while the NLDN does not provide adequate spatial mapping of these flashes. The KSC LMA system has much better location accuracy, and provides excellent 3-dimensional representation within 100 km of KSC. It also has sufficient sensitivity to provide 2-dimensional flash mapping within 250 km of KSC. The MERLIN system provides a more-detailed representation of fast leader propagation (in 2 dimensions) with 100 km of KSC. Earlier work during the CHUVA campaign in Brazil with similar systems and the (orbital) Lightning Imaging System (LIS) has shown that the interferometric data correlated much better in space and time with the LIS optical observations. We are currently investigating this relationship at KSC, where both the LMA and interferometer perform much better than the systems used during CHUVA.

The Interferometric View of Lightning

NASA Astrophysics Data System (ADS)

Stock, M.; Lapierre, J. L.

2017-12-01

Recent advances in off the shelf high-speed digitizers has enabled vast improvements in broadband, digital VHF interferometers. These simple instruments consist of 3 or more VHF antennas distributed in an array which are then digitized at a speed above the Nyquist frequency of the antenna bandwidth (usually 200+ MHz). Broadband interferometers are capable of creating very detailed maps of lightning, with time resolution better than 1us, and angular resolution only limited by their baseline lengths. This is combined with high sensitivity, and the ability to locate both continuously emitting and impulsive radiation sources. They are not without their limitations though. Because the baselines are relatively short, the maps are only 2-dimensional (direction to the source), unless many antennas are used only a single VHF radiation source can be located at any instant, and because the antennas are almost always arranged in a planar array they are better suited for observing lightning at high elevation angles. Even though imperfect, VHF interferometers provide one of the most detailed views of the behavior of lightning flashes inside a cloud. This presentation will present the overall picture of in-cloud lightning as seen by VHF interferometers. Most flashes can be split into 3 general phases of activity. Phase 1 is the initiation phase, covering all activity until the negative leader completes its vertical extension, and includes both lightning initiation and initial breakdown pulses. Phase 2 is the active phase and includes all activity during the horizontal extension of the negative leader. During Phase 2, any K-processes which occur tend to be short in duration and extent. Phase 3 is the final phase, and includes all activity after the negative leader stops propagating. During Phase 3, the conductivity of the lightning channels starts to decline, and extensive K-processes are seen which traverse the entire channel structure, this is also the period in which regular pulse trains tend to be observed. Not all flashes fit this fairly simplistic structure, in particular some flashes seem to lack a vertically developing negative leader, and others seem to lack activity after the negative leader stops propagating. Still, this basic anatomy of an in-cloud flash proves useful in describing the overall structure of a lightning flash.

The North Alabama Lightning Mapping Array: Recent Results and Future Prospects

NASA Technical Reports Server (NTRS)

Goodman, S. J.; Blakeslee, R.; Christian, H.; Boccippio, D.; Koshak, W.; Bailey, J.; Hall, J.; Bateman, M.; McCaul, E.; Buechler, D.

2002-01-01

The North Alabama Lightning Mapping Array became operational in November 2001 as a principal component of a severe weather test bed to infuse new science and technologies into the short-term forecasting of severe and hazardous weather and the warning decision-making process. The LMA project is a collaboration among NASA scientists, National Weather Service (NWS) weather forecast offices (WFOs), emergency managers, and other partners. The time rate-of-change of storm characteristics and life-cycle trending are accomplished in real-time through the second generation Lightning Imaging Sensor Data Applications Display (LISDAD II) system, initially developed in T997 through a collaboration among NASA/MSFC, MIT/Lincoln Lab and the Melbourne, FL WFO. LISDAD II is now a distributed decision support system with a JAVA-based display application that allows anyone, anywhere to track individual storm histories within the Tennessee Valley region of the southeastern U.S. Since the inauguration of the LMA there has been an abundance of severe weather. During 23-24 November 2001, a major tornado outbreak was monitored by LMA in its first data acquisition effort (36 tornadoes in Alabama). Since that time the LMA has collected a vast amount of data on hailstorms and damaging wind events, non-tornadic supercells, and ordinary non-severe thunderstorms. In this paper we provide an overview of LMA observations and discuss future prospects for improving the short-term forecasting of convective weather.

The GOES-R Lightning Mapper Sensor

NASA Technical Reports Server (NTRS)

Buechler, Dennis; Christian, Hugh; Goodman, Steve

2004-01-01

The Lightning Mapper Sensor on GOES-R builds on previous measurements of lightning from low earth orbit by the OTD (Optical Transient Detector) and LIS (Lightning Imaging Sensor) sensors. Unlike observations from low earth orbit, the GOES-R platform will allow continuous monitoring of lightning activity over the Continental United States and southern Canada, Central and South America, and portions of the Atlantic and Pacific Oceans. The LMS will detect total (cloud-to-ground and intracloud) lightning at storm scale resolution (approx. 8 km) using a highly sensitive Charge Coupled Device (CCD) detector array. Discrimination between lightning optical transients and a bright sunlit background scene is accomplished by employing spectral, spatial, and temporal filtering along with a background subtraction technique. The result is 24 hour detection capability of total lightning. These total lightning observations can be made available to users within about 20 seconds. Research indicates a number of ways that total lightning observations from LMS could benefit operational activities, including 1) potential increases in lead times and reduced false alarms for severe thunderstorm and tornado Warnings, 2) improved routing of &rail around thunderstorms, 3) support for spacecraft launches and landings, 4) improved ability to monitor tropical cyclone intensity, 5) ability to monitor thunderstorm intensification/weakening during radar outages or where radar coverage is poor, 6) better identification of deep convection for the initialization of numerical prediction models, 7) improved forest fire forecasts, 8) identification of convective initiation, 9) identification of heavy convective snowfall, and 10) enhanced temporal resolution of storm evolution (1 minute) than is available from radar observations. Total lightning data has been used in an operational environment since July 2003 at the Huntsville, Alabama National Weather Service office. Total lightning measurements are obtained by the North Alabama Lightning Mapping Array (LMA) and have successfully been used in warning decisions. Every 2 minutes, total lightning counts in 2 km by 2 km horizontal, 1 km vertical grids are available to forecasters on an AWIPS (Advanced Weather Interactive Processing System) workstation. Experience with the LMA total lightning data is used to illustrate the potential use of LMS data that would be available to forecasters across the US. This abstract is for submission as a presentation to the National Weather Association Annual Meeting to be held 16-21 October 2004 in Portland, OR. This abstract will be published in the conference proceedings.

The GOES-R GeoStationary Lightning Mapper (GLM)

NASA Technical Reports Server (NTRS)

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

2011-01-01

The Geostationary Operational Environmental Satellite (GOES-R) is the next series to follow the existing GOES system currently operating over the Western Hemisphere. Superior spacecraft and instrument technology will support expanded detection of environmental phenomena, resulting in more timely and accurate forecasts and warnings. Advancements over current GOES capabilities include a new capability for total lightning detection (cloud and cloud-to-ground flashes) from the Geostationary Lightning Mapper (GLM), and improved capability for the Advanced Baseline Imager (ABI). The Geostationary Lighting Mapper (GLM) will map total lightning activity (in-cloud and cloud-to-ground lighting flashes) continuously day and night with near-uniform spatial resolution of 8 km with a product refresh rate of less than 20 sec over the Americas and adjacent oceanic regions. This will aid in forecasting severe storms and tornado activity, and convective weather impacts on aviation safety and efficiency among a number of potential applications. In parallel with the instrument development (a prototype and 4 flight models), a GOES-R Risk Reduction Team and Algorithm Working Group Lightning Applications Team have begun to develop the Level 2 algorithms (environmental data records), cal/val performance monitoring tools, and new applications using GLM alone, in combination with the ABI, merged with ground-based sensors, and decision aids augmented by numerical weather prediction model forecasts. Proxy total lightning data from the NASA Lightning Imaging Sensor on the Tropical Rainfall Measuring Mission (TRMM) satellite and regional test beds are being used to develop the pre-launch algorithms and applications, and also improve our knowledge of thunderstorm initiation and evolution. An international field campaign planned for 2011-2012 will produce concurrent observations from a VHF lightning mapping array, Meteosat multi-band imagery, Tropical Rainfall Measuring Mission (TRMM) Lightning Imaging Sensor (LIS) overpasses, and related ground and in-situ lightning and meteorological measurements in the vicinity of Sao Paulo. These data will provide a new comprehensive proxy data set for algorithm and application development.

Pre-Launch Algorithms and Risk Reduction in Support of the Geostationary Lightning Mapper for GOES-R and Beyond

NASA Technical Reports Server (NTRS)

Goodman, Steven; Blakeslee, Richard; Koshak, William

2008-01-01

The Geostationary Lightning Mapper (GLM) is a single channel, near-IR optical transient event detector, used to detect, locate and measure total lightning activity over the full-disk as part of a 3-axis stabilized, geostationary weather satellite system. The next generation NOAA Geostationary Operational Environmental Satellite (GOES-R) series with a planned launch in 2014 will carry a GLM that will provide continuous day and night observations of lightning from the west coast of Africa (GOES-E) to New Zealand (GOES-W) when the constellation is fully operational. The mission objectives for the GLM are to 1) provide continuous,full-disk lightning measurements for storm warning and Nowcasting, 2) provide early warning of tornado activity, and 3) accumulate a long-term database to track decadal changes of lightning. The GLM owes its heritage to the NASA Lightning Imaging Sensor (1997-Present) and the Optical Transient Detector (1995-2000), which were developed for the Earth Observing System and have produced a combined 13 year data record of global lightning activity. Instrument formulation studies were completed in March 2007 and the implementation phase to develop a prototype model and up to four flight units is expected to begin in latter part of the year. In parallel with the instrument development, a GOES-R Risk Reduction Team and Algorithm Working Group Lightning Applications Team have begun to develop the Level 2B algorithms and applications. Proxy total lightning data from the NASA Lightning Imaging Sensor on the Tropical Rainfall Measuring Mission (TRMM) satellite and regional test beds (e.g., Lightning Mapping Arrays in North Alabama and the Washington DC Metropolitan area) are being used to develop the pre-launch algorithms and applications, and also improve our knowledge of thunderstorm initiation and evolution. Real time lightning mapping data provided to selected National Weather Service forecast offices in Southern and Eastern Region are also improving our understanding of the application of these data in the severe storm warning process and help to accelerate the development of the pre-launch algorithms and Nowcasting applications.

Pre-Launch Algorithms and Risk Reduction in Support of the Geostationary Lightning Mapper for GOES-R and Beyond

NASA Technical Reports Server (NTRS)

Goodman, Steven; Blakeslee, Richard; Koshak, William; Petersen, Walt; Buechler, Dennis; Krehbiel, Paul; Gatlin, Patrick; Zubrick, Steven

2008-01-01

The Geostationary Lightning Mapper (GLM) is a single channel, near-IR optical transient event detector, used to detect, locate and measure total lightning activity over the full-disk as part of a 3-axis stabilized, geostationary weather satellite system. The next generation NOAA Geostationary Operational Environmental Satellite (GOES-R) series with a planned launch in 2014 will carry a GLM that will provide continuous day and night observations of lightning from the west coast of Africa (GOES-E) to New Zealand (GOES-W) when the constellation is fully operational.The mission objectives for the GLM are to 1) provide continuous,full-disk lightning measurements for storm warning and Nowcasting, 2) provide early warning of tornadic activity, and 3) accumulate a long-term database to track decadal changes of lightning. The GLM owes its heritage to the NASA Lightning Imaging Sensor (1997-Present) and the Optical Transient Detector (1995-2000), which were developed for the Earth Observing System and have produced a combined 13 year data record of global lightning activity. Instrument formulation studies were completed in March 2007 and the implementation phase to develop a prototype model and up to four flight units is expected to begin in latter part of the year. In parallel with the instrument development, a GOES-R Risk Reduction Team and Algorithm Working Group Lightning Applications Team have begun to develop the Level 2B algorithms and applications. Proxy total lightning data from the NASA Lightning Imaging Sensor on the Tropical Rainfall Measuring Mission (TRMM) sate]lite and regional test beds (e.g., Lightning Mapping Arrays in North Alabama and the Washington DC Metropolitan area) are being used to develop the pre-launch algorithms and applications, and also improve our knowledge of thunderstorm initiation and evolution. Real time lightning mapping data provided to selected National Weather Service forecast offices in Southern and Eastern Region are also improving our understanding of the application of these data in the severe storm warning process and help to accelerate the development of the pre-launch algorithms and Nowcasting applications. Abstract for the 3 rd Conference on Meteorological

Inter-Comparison of Lightning Trends from Ground-Based Networks During Severe Weather: Applications Toward GLM

NASA Technical Reports Server (NTRS)

Carey, Lawrence D.; Schultz, Chris J.; Petersen, Walter A.; Rudlosky, Scott D.; Bateman, Monte; Cecil, Daniel J.; Blakeslee, Richard J.; Goodman, Steven J.

2011-01-01

The planned GOES-R Geostationary Lightning Mapper (GLM) will provide total lightning data on the location and intensity of thunderstorms over a hemispheric spatial domain. Ongoing GOES-R research activities are demonstrating the utility of total flash rate trends for enhancing forecasting skill of severe storms. To date, GLM total lightning proxy trends have been well served by ground-based VHF systems such as the Northern Alabama Lightning Mapping Array (NALMA). The NALMA (and other similar networks in Washington DC and Oklahoma) provide high detection efficiency (> 90%) and location accuracy (< 1 km) observations of total lightning within about 150 km from network center. To expand GLM proxy applications for high impact convective weather (e.g., severe, aviation hazards), it is desirable to investigate the utility of additional sources of continuous lightning that can serve as suitable GLM proxy over large spatial scales (order 100 s to 1000 km or more), including typically data denied regions such as the oceans. Potential sources of GLM proxy include ground-based long-range (regional or global) VLF/LF lightning networks such as the relatively new Vaisala Global Lightning Dataset (GLD360) and Weatherbug Total Lightning Network (WTLN). Before using these data in GLM research applications, it is necessary to compare them with LMAs and well-quantified cloud-to-ground (CG) lightning networks, such as Vaisala s National Lightning Detection Network (NLDN), for assessment of total and CG lightning location accuracy, detection efficiency and flash rate trends. Preliminary inter-comparisons from these lightning networks during selected severe weather events will be presented and their implications discussed.

Lightning Mapping Observations During DC3 in Northern Colorado

NASA Astrophysics Data System (ADS)

Krehbiel, P. R.; Rison, W.; Thomas, R. J.

2012-12-01

The Deep Convective Clouds and Chemistry Experiment (DC3) was conducted in three regions covered by Lightning Mapping Arrays (LMAs): Oklahoma and west Texas, northern Alabama, and northern Colorado. In this and a companion presentation, we discuss results obtained from the newly-deployed North Colorado LMA. The CO LMA revealed a surprising variety of lightning-inferred electrical structures, ranging from classic tripolar, normal polarity storms to several variations of anomalously electrified systems. Storms were often characterized by a pronounced lack or deficit of cloud-to-ground discharges (negative or positive), both in relative and absolute terms compared to the large amount of intracloud activity revealed by the LMA. Anomalous electrification was observed in small, localized storms as well as in large, deeply convective and severe storms. Another surprising observation was the frequent occurrence of embedded convection in the downwind anvil/outflow region of large storm systems. Observations of discharges in low flash rate situations over or near the network are sufficiently detailed to enable branching algorithms to estimate total channel lengths for modeling NOx production. However, this will not be possible in large or distant storm systems where the lightning was essentially continuous and structurally complex, or spatially noisy. Rather, a simple empirical metric for characterizing the lightning activity can be developed based on the number of located VHF radiation sources, weighted for example by the peak source power, source altitude, and temporal duration.

GOES-R Geostationary Lightning Mapper Performance Specifications and Algorithms

NASA Technical Reports Server (NTRS)

Mach, Douglas M.; Goodman, Steven J.; Blakeslee, Richard J.; Koshak, William J.; Petersen, William A.; Boldi, Robert A.; Carey, Lawrence D.; Bateman, Monte G.; Buchler, Dennis E.; McCaul, E. William, Jr.

2008-01-01

The Geostationary Lightning Mapper (GLM) is a single channel, near-IR imager/optical transient event detector, used to detect, locate and measure total lightning activity over the full-disk. The next generation NOAA Geostationary Operational Environmental Satellite (GOES-R) series will carry a GLM that will provide continuous day and night observations of lightning. The mission objectives for the GLM are to: (1) Provide continuous, full-disk lightning measurements for storm warning and nowcasting, (2) Provide early warning of tornadic activity, and (2) Accumulate a long-term database to track decadal changes of lightning. The GLM owes its heritage to the NASA Lightning Imaging Sensor (1997- present) and the Optical Transient Detector (1995-2000), which were developed for the Earth Observing System and have produced a combined 13 year data record of global lightning activity. GOES-R Risk Reduction Team and Algorithm Working Group Lightning Applications Team have begun to develop the Level 2 algorithms and applications. The science data will consist of lightning "events", "groups", and "flashes". The algorithm is being designed to be an efficient user of the computational resources. This may include parallelization of the code and the concept of sub-dividing the GLM FOV into regions to be processed in parallel. Proxy total lightning data from the NASA Lightning Imaging Sensor on the Tropical Rainfall Measuring Mission (TRMM) satellite and regional test beds (e.g., Lightning Mapping Arrays in North Alabama, Oklahoma, Central Florida, and the Washington DC Metropolitan area) are being used to develop the prelaunch algorithms and applications, and also improve our knowledge of thunderstorm initiation and evolution.

High-Energy Particle Showers Observed at Ground Level in Coincidence with Downward Lightning Leaders at the Telescope Array Observatory

NASA Astrophysics Data System (ADS)

Belz, John; Abbasi, Rasha; Le Von, Ryan; Krehbiel, Paul; Remington, Jackson; Rison, William

Terrestrial Gamma Ray Flashes (TGFs) detected by satellite observations have been shown to be generated by upward propagating negative leaders at altitudes of about 10 to 12 km above Mean Sea Level (MSL), and have durations ranging between a few hundred microseconds and a few milliseconds. The Telescope Array Cosmic Ray observatory, designed to observe air showers induced by ultra high energy cosmic rays, includes a surface scintillator detector (SD) covering approximately 700 square kilometers on a 1.2 km grid. Following the observation of anomalous SD triggers correlated with local lightning activity, a Lightning Mapping Array (LMA) and slow electric field antenna were installed at the TA site in order to characterize the lightning associated with these anomalous triggers. In this talk, we present evidence that the anomalous triggers are produced during the initial breakdown phase of fast, downward propagating, negative leaders above the detectors which produced the triggers. The durations of the high energy radiation are a few hundred microseconds, similar to satellite observations of TGFs. The triggers were produced within a few hundred microseconds of the initiation of the leaders, when the leaders were at an altitude of about 3 to 4 km MSL. The TA scintillation detectors are not optimized for gamma ray detection, however we present the results of simulations demonstrating that the fluxes observed are consistent with this picture. We conclude that the anomalous triggers observed by TA are clearly due to high energy radiation produced by the fast downward propagating negative leaders, and are probably downward-directed TGFs.

Observational and Modeling-based Study of Corsica Thunderstorms: Preparation of the EXAEDRE Airborne Campaign

NASA Astrophysics Data System (ADS)

Defer, E.; Coquillat, S.; Lambert, D.; Pinty, J. P.; Prieur, S.; Caumont, O.; Labatut, L.; Nuret, M.; Blanchet, P.; Buguet, M.; Lalande, P.; Labrouche, G.; Pedeboy, S.; Lojou, J. Y.; Schwarzenboeck, A.; Delanoë, J.; Bourdon, A.; Guiraud, L.

2017-12-01

The 4-year EXAEDRE (EXploiting new Atmospheric Electricity Data for Research and the Environment; Oct 2016-Sept 2020) project is sponsored by the French Science Foundation ANR (Agence Nationale de la Recherche). This project is a French contribution to the HyMeX (HYdrological cycle in the Mediterranean EXperiment) program. The EXAEDRE activities rely on innovative multi-disciplinary and state of the art instrumentation and modeling tools to provide a comprehensive description of the electrical activity in thunderstorms. The EXAEDRE observational part is based on i) existing lightning records collected during HyMeX Special Observation Period (SOP1; Sept-Nov 2012), and permanent lightning observations provided by the research Lightning Mapping Array SAETTA and the operational Météorage lightning locating systems, ii) additional lightning observations mapped with a new VHF interferometer especially developed within the EXAEDRE project, and iii) a dedicated airborne campaign over Corsica. The modeling part of the EXAEDRE project exploits the electrification and lightning schemes developed in the cloud resolving model MesoNH and promotes an innovative technique of flash data assimilation in the french operational model AROME of Météo-France. An overview of the EXAEDRE project will be given with an emphasis on the instrumental, observational and modeling activities performed during the 1st year of the project. The preparation of the EXAEDRE airborne campaign scheduled for September 2018 over Corsica will then be discussed. Acknowledgements. The EXAEDRE project is sponsored by grant ANR-16-CE04-0005 with support from the MISTRALS/HyMeX meta program.

The North Alabama Severe Thunderstorm Observations, Research, and Monitoring Network (STORMnet)

NASA Technical Reports Server (NTRS)

Goodman, S. J.; Blakeslee, R.; Christian, H.; Boccippio, D.; Koshak, W.; Bailey, J.; Hall, J.; Bateman, M.; McCaul, E.; Buechler, D.;

Imaging thunder

NASA Astrophysics Data System (ADS)

Johnson, J. B.; Arechiga, R. O.; Thomas, R. J.; Edens, H. E.; Anderson, J.; Johnson, R. L.

2011-12-01

We use a network of broadband microphones, including a 4-element array, to locate the sources of thunder occurring during an electrical storm in central New Mexico on July 24th, 2009. Combined slowness search and distance ranging are used to identify thunder regions in three dimensions (out to 12 km) and for two overlapping frequency bands (1-10 and 4-40 Hz). Distinct thunder pulses are locatable and used to predict time-of-arrival to neighboring stations and to identify correlated phases across the network. Spatial correlation is also found between the thunder source regions and regions of VHF radiation as located by the New Mexico Lightning Mapping Array (LMA). Some of the misfit between the LMA and thunder locations is attributable to differences in excitation mechanisms of the respective radiation, which is related to current impulses in lightning channels (for thunder) and incremental ionization of the atmosphere (for VHF emissions).

Imaging thunder

NASA Astrophysics Data System (ADS)

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

2011-10-01

We use a network of broadband microphones, including a 4-element array, to locate the sources of thunder occurring during an electrical storm in central New Mexico on July 24th, 2009. Combined slowness search and distance ranging are used to identify thunder regions in three dimensions (out to 12 km) and for two overlapping frequency bands (1-10 and 4-40 Hz). Distinct thunder pulses are locatable and used to predict time-of-arrival to neighboring stations and to identify correlated phases across the network. Spatial correlation is also found between the thunder source regions and regions of very high frequency (VHF) radiation as located by the New Mexico Lightning Mapping Array (LMA). Some of the misfit between the LMA and thunder locations is attributable to differences in excitation mechanisms of the respective radiation, which is related to current impulses in lightning channels (for thunder) and incremental ionization of the atmosphere (for VHF emissions).

Mini Array for TLE Detection

NASA Astrophysics Data System (ADS)

Fullekrug, M.; Liu, Z.; Koh, K.; Mezentsev, A.; Pedeboy, S.; Soula, S.; Sugier, J.; Enno, S. E.; Rycroft, M. J.

2016-12-01

Transient Luminous Events (TLEs) can generate electromagnetic radiation at frequencies 100 kHz (Qin et al., 2012, Fullekrug et al., 2013) and <1 kHz (Pasko et al., GRL, 1998, Cummer et al., GRL, 1998)as a result of the splitting and exponential growth of streamer discharges (Pasko, JGR, 2010, McHarg, JGR, 2010). The electromagnetic radiation results from the coherent superposition of the very weak signalsfrom thousands of small scale streamer discharges at 40 km height for frequencies 100 kHz and at 80 km height for frequencies <1 kHz. It seems therefore plausible that TLEs can also generate electromagnetic waves at intermediate heights, e.g. 60 km with frequencies between 1-100 kHz, e.g., 10 kHz. However, this frequency range is dominated by the powerful electromagnetic radiation from return strokes and it is hence commonly thought that this radiation can not easily be detectedwith single radio receivers. This study proposes to search for electromagnetic radiation from TLEsabove thunderclouds by use of a mini array that has the ability to determine the elevation angle toward the radiation source. Mini arrays with small apertures are used for infrasonic and seismic studies to determine source mechanisms and properties of the medium through which the waves propagate. For the detection of electromagneticradiation, the array processing is adapted for the fast propagationat the speed of light. Here we report for the first time the detection and mapping of distant lightning strokes in the sky with a mini array located near Bath in the UK. The array has a baseline to wavelength ratio 4.2 10^{-2} to record electromagnetic waves from 2-18 kHz. It is found that the mini array detects 69 lightning strokes per second from cloud-to-ground and in-cloud discharges, even though the parent thunderstorms are 900-1,100 km away and a rigorous selection criterion based on the spatial coherency of the electromagnetic source field across the array is used. About 14% of the lightning strokes appear at larger elevation angles in the sky than the remaining 86% of lightning strokes as the result of birefringent subionospheric wave propagation attributed to ordinary and extra-ordinary waves. These results imply that mini arrays can be used to detect electromagnetic radiation from TLEs above thunderclouds in different frequency ranges.

Exploring a Physically Based Tool for Lightning Cessation: A Preliminary Study

NASA Technical Reports Server (NTRS)

Schultz, Elise V.; Petersen, Walter a.; Carey, Lawrence D.; Deierling, Wiebke

2010-01-01

The University of Alabama in Huntsville (UA Huntsville) and NASA's Marshall Space Flight Center are collaborating with the 45th Weather Squadron (45WS) at Cape Canaveral Air Force Station (CCAFS) to enable improved nowcasting of lightning cessation. The project centers on use of dual-polarimetric radar capabilities, and in particular, the new C-band dual-polarimetric weather radar acquired by the 45WS. Special emphasis is placed on the development of a physically based operational algorithm to predict lightning cessation. While previous studies have developed statistically based lightning cessation algorithms, we believe that dual-polarimetric radar variables offer the possibility to improve existing algorithms through the inclusion of physically meaningful trends reflecting interactions between in-cloud electric fields and microphysics. Specifically, decades of polarimetric radar research using propagation differential phase has demonstrated the presence of distinct phase and ice crystal alignment signatures in the presence of strong electric fields associated with lightning. One question yet to be addressed is: To what extent can these ice-crystal alignment signatures be used to nowcast the cessation of lightning activity in a given storm? Accordingly, data from the UA Huntsville Advanced Radar for Meteorological and Operational Research (ARMOR) along with the North Alabama Lightning Mapping Array are used in this study to investigate the radar signatures present before and after lightning cessation. A summary of preliminary results will be presented.

Exploring a Physically Based Tool for Lightning Cessation: Preliminary Results

NASA Technical Reports Server (NTRS)

Schultz, Elsie V.; Petersen, Walter A.; Carey, Lawrence D.; Buechler, Dennis E.; Gatlin, Patrick N.

2010-01-01

The University of Alabama in Huntsville (UAHuntsville) and NASA s Marshall Space Flight Center are collaborating with the 45th Weather Squadron (45WS) at Cape Canaveral Air Force Station (CCAFS) to enable improved nowcasting of lightning cessation. The project centers on use of dual-polarimetric radar capabilities, and in particular, the new C-band dual-polarimetric weather radar acquired by the 45WS. Special emphasis is placed on the development of a physically based operational algorithm to predict lightning cessation. While previous studies have developed statistically based lightning cessation algorithms, we believe that dual-polarimetric radar variables offer the possibility to improve existing algorithms through the inclusion of physically meaningful trends reflecting interactions between in-cloud electric fields and microphysics. Specifically, decades of polarimetric radar research using propagation differential phase has demonstrated the presence of distinct phase and ice crystal alignment signatures in the presence of strong electric fields associated with lightning. One question yet to be addressed is: To what extent can these ice-crystal alignment signatures be used to nowcast the cessation of lightning activity in a given storm? Accordingly, data from the UAHuntsville Advanced Radar for Meteorological and Operational Research (ARMOR) along with the North Alabama Lightning Mapping Array are used in this study to investigate the radar signatures present before and after lightning cessation. A summary of preliminary results will be presented.

Small negative cloud-to-ground lightning reports at the NASA Kennedy Space Center and Air Force Eastern Range

NASA Astrophysics Data System (ADS)

Wilson, Jennifer G.; Cummins, Kenneth L.; Krider, E. Philip

2009-12-01

The NASA Kennedy Space Center (KSC) and Air Force Eastern Range (ER) use data from two cloud-to-ground (CG) lightning detection networks, the Cloud-to-Ground Lightning Surveillance System (CGLSS) and the U.S. National Lightning Detection Network™ (NLDN), and a volumetric lightning mapping array, the Lightning Detection and Ranging (LDAR) system, to monitor and characterize lightning that is potentially hazardous to launch or ground operations. Data obtained from these systems during June-August 2006 have been examined to check the classification of small, negative CGLSS reports that have an estimated peak current, ∣Ip∣ less than 7 kA, and to determine the smallest values of Ip that are produced by first strokes, by subsequent strokes that create a new ground contact (NGC), and by subsequent strokes that remain in a preexisting channel (PEC). The results show that within 20 km of the KSC-ER, 21% of the low-amplitude negative CGLSS reports were produced by first strokes, with a minimum Ip of -2.9 kA; 31% were by NGCs, with a minimum Ip of -2.0 kA; and 14% were by PECs, with a minimum Ip of -2.2 kA. The remaining 34% were produced by cloud pulses or lightning events that we were not able to classify.

GLM Validation Studies in Colorado

NASA Astrophysics Data System (ADS)

Rutledge, S. A.; Reimel, K.; Fuchs, B.; Xu, W.

2017-12-01

On 8 May 2017 the Geostationary Lightning Mapper (GLM) calibration/validation field campaign completed a mission over the domain of the Colorado Lightning Mapping Array (LMA). This "gold mine day" produced a mixture of normal polarity and anomalous storms of varying intensity. A case study analysis has been completed for a portion of three individual storms from this day. By utilizing a cell tracking algorithm and lightning flash attribution program, individual lightning flashes detected by the GLM, LMA, the National Lightning Detection Network (NLDN), and Earth Networks Total Lightning Network (ENTLN) are attributed to individual storm cells. The focus of this analysis is the detection efficiency of GLM. We will discuss how the GLM detection efficiency changes as a result of storm morphology and lightning flash characteristics. Lightning flash size, flash height, and the amount of ice present between the lightning flash altitude and the top of the cloud all appear to play a role in how well GLM detects lightning flashes. Since GLM shares the same concept as its predecessor TRMM LIS (optically-based lightning detection), the evaluation of TRMM LIS against LMA network-detected lightning provides insights into the GLM detection efficiency. We have collected observations by LIS and LMA coincident in time and space during 2008-2014. The sample includes 400 LIS overpasses with both LIS and LMA detecting flashes within 150 km radius of the center of the LMA array during the 120 second LIS observing time period (analysis presently confined to the Alabama LMA network). The overall LIS detection efficiency (DE, defined as the ratio of flash rates between LIS and LMA) is 0.45, with higher DE for lower flash rate cases. LIS showed a DE of nearly 100% for cases with flash rates < 10 fl/min, but had a DE of only 20-30% for high flash rates within intense storms (> 300 fl/min). We further separated the dataset into day and night, and found that the night-time DE (0.6) increased by 20% compared to day-time DE (0.5). LIS DE also increased as a function of LMA-derived flash size, possibly due to stronger radiance from larger flashes. LIS DE was the lowest ( 40%) for flashes with sizes smaller than a single LIS pixel (< 16 km2). These results may be applicable to GLM as well.

Coincident Observation of Lightning using Spaceborne Spectrophotometer and Ground-Level Electromagnetic Sensors

NASA Technical Reports Server (NTRS)

Adachi, Toru; Cohen, Morris; Li, Jingbo; Cummer, Steve; Blakeslee, Richard; Marshall, THomas; Stolzenberg, Maribeth; Karunarathne, Sumedhe; Hsu, Rue-Ron; Su, Han-Tzong;

Sprite-producing Convective Storms within the Colorado Lightning Mapping Array

NASA Astrophysics Data System (ADS)

Lyons, W. A.; Cummer, S. A.; Rison, W.; Krehbiel, P. R.; Lang, T. J.; Rutledge, S. A.; Lu, G.; Stanley, M. A.; Ashcraft, T.; Nelson, T. E.

2012-12-01

The multi-year, multi-institution effort entitled Physical Origins of Coupling to the Upper Atmosphere from Lightning (PhOCAL), has among its goals to qualitatively understand the meteorology and lightning flash characteristics that produce the unusual and/or very energetic lightning responsible for phenomena such as sprites, halos, elves, blue jets and gigantic jets, collectively known as Transient Luminous Events (TLEs). A key task is to obtain simultaneous video, ideally with a high-speed imager (HSI), of both a TLE and its parent lightning discharge, within the domain of a 3-D Lightning Mapping Array (LMA). While conceptually simple, this task is logistically quite complicated. In 2012, a new 15-station Colorado LMA (COLMA) became operational, covering northeastern Colorado, with the Yucca Ridge Field Station (YRFS) near its western edge. The National Charge Moment Change Network (CMCN), which since 2007 has been documenting sprite-class +CGs (those with impulse change moment changes >100 C km), indicates that a strong gradient of energetic +CGs exists west-to-east through the COLMA, with the most likely region for sprite-producing storms being in the COLMA eastern fringes (western Kansas and Nebraska). Yet, on 8 and 25 June, 2012, intense convective systems formed in the COLMA along and just east of the Front Range, producing severe weather and intense lightning. On the 8th, four sprite parent +CGs were captured at 3000 fps from YRFS with the sprites confirmed by dual (conventional speed) cameras in New Mexico. In a second storm on the 25th, viewing conditions prevented +CG video acquisition, but sprites were logged over the COLMA and detailed reconstructions of the discharges are being made. The parent discharges often began as upward negative leaders propagating into a mid-level positive charge layer at 8-10 km. They often originated within or near the convective core before expanding outward into a stratiform region and involving several hundred square kilometers, to be followed by +CG and strong continuing currents. LMA indications of recoil leaders appear confirmed by some high-speed video. These storms were somewhat smaller than the typical sprite-bearing MCS. The storm structures will be categorized using GOES IR, NEXRAD reflectivity, NLDN lightning data, CMCN impulse charge moment data, and full charge moment charge retrievals. The sprite parent CG discharges will be cataloged along with their points of origin, the height and volume from which charge is removed, the charge lowered to ground, and the continuing current characteristics. These CGs will be placed in the context of the storms' meteorological structure and evolution.

Pre-Launch Algorithms and Risk Reduction in Support of the Geostationary Lightning Mapper for GOES-R and Beyond

NASA Technical Reports Server (NTRS)

Goodman, Steven J.; Blakeslee, R. J.; Koshak, W.; Petersen, W.; Buechler, D. E.; Krehbiel, P. R.; Gatlin, P.; Zubrick, S.

2008-01-01

The Geostationary Lightning Mapper (GLM) is a single channel, near-IR imager/optical transient event detector, used to detect, locate and measure total lightning activity over the full-disk as part of a 3-axis stabilized, geostationary weather satellite system. The next generation NOAA Geostationary Operational Environmental Satellite (GOES-R) series with a planned launch in 2014 will carry a GLM that will provide continuous day and night observations of lightning from the west coast of Africa (GOES-E) to New Zealand (GOES-W) when the constellation is fUlly operational. The mission objectives for the GLM are to 1) provide continuous, full-disk lightning measurements for storm warning and nowcasting, 2) provide early warning of tornadic activity, and 3) accumulate a long-term database to track decadal changes of lightning. The GLM owes its heritage to the NASA Lightning Imaging Sensor (1997-Present) and the Optical Transient Detector (1995-2000), which were developed for the Earth Observing System and have produced a combined 13 year data record of global lightning activity. Instrument formulation studies were completed in March 2007 and the implementation phase to develop a prototype model and up to four flight models is expected to be underway in the latter part of 2007. In parallel with the instrument development, a GOES-R Risk Reduction Team and Algorithm Working Group Lightning Applications Team have begun to develop the Level 2 ground processing algorithms and applications. Proxy total lightning data from the NASA Lightning Imaging Sensor on the Tropical Rainfall Measuring Mission (TRMM) satellite and regional test beds (e.g., Lightning Mapping Arrays in North Alabama and the Washington DC Metropolitan area)

Use of High-Resolution WRF Simulations to Forecast Lightning Threat

NASA Technical Reports Server (NTRS)

McCaul, E. W., Jr.; LaCasse, K.; Goodman, S. J.; Cecil, D. J.

2008-01-01

Recent observational studies have confirmed the existence of a robust statistical relationship between lightning flash rates and the amount of large precipitating ice hydrometeors aloft in storms. This relationship is exploited, in conjunction with the capabilities of cloud-resolving forecast models such as WRF, to forecast explicitly the threat of lightning from convective storms using selected output fields from the model forecasts. The simulated vertical flux of graupel at -15C and the shape of the simulated reflectivity profile are tested in this study as proxies for charge separation processes and their associated lightning risk. Our lightning forecast method differs from others in that it is entirely based on high-resolution simulation output, without reliance on any climatological data. short [6-8 h) simulations are conducted for a number of case studies for which three-dmmensional lightning validation data from the North Alabama Lightning Mapping Array are available. Experiments indicate that initialization of the WRF model on a 2 km grid using Eta boundary conditions, Doppler radar radial velocity fields, and METAR and ACARS data y&eld satisfactory simulations. __nalyses of the lightning threat fields suggests that both the graupel flux and reflectivity profile approaches, when properly calibrated, can yield reasonable lightning threat forecasts, although an ensemble approach is probably desirable in order to reduce the tendency for misplacement of modeled storms to hurt the accuracy of the forecasts. Our lightning threat forecasts are also compared to other more traditional means of forecasting thunderstorms, such as those based on inspection of the convective available potential energy field.

Charge structure in volcanic plumes: a comparison of plume properties predicted by an integral plume model to observations of volcanic lightning during the 2010 eruption of Eyjafjallajökull, Iceland.

PubMed

Woodhouse, Mark J; Behnke, Sonja A

Observations of volcanic lightning made using a lightning mapping array during the 2010 eruption of Eyjafjallajökull allow the trajectory and growth of the volcanic plume to be determined. The lightning observations are compared with predictions of an integral model of volcanic plumes that includes descriptions of the interaction with wind and the effects of moisture. We show that the trajectory predicted by the integral model closely matches the observational data and the model well describes the growth of the plume downwind of the vent. Analysis of the lightning signals reveals information on the dominant charge structure within the volcanic plume. During the Eyjafjallajökull eruption both monopole and dipole charge structures were observed in the plume. By using the integral plume model, we propose the varying charge structure is connected to the availability of condensed water and low temperatures at high altitudes in the plume, suggesting ice formation may have contributed to the generation of a dipole charge structure via thunderstorm-style ice-based charging mechanisms, though overall this charging mechanism is believed to have had only a weak influence on the production of lightning.

Oceanic Storm Characteristics Off the Kennedy Space Center Coast

NASA Technical Reports Server (NTRS)

Wilson, J.; Simpson, A. A.; Cummins, K. L.; Kiriazes, J. J.; Brown, R. G.; Mata, C. T.

2014-01-01

Natural cloud-to-ground lightning may behave differently depending on the characteristics of the attachment mediums, including the peak current (inferred from radiation fields) and the number of ground strike locations per flash. Existing literature has raised issues over the yea"rs on the behavior of lightning over ocean terrain and these phenomena are not yet well understood. To investigate lightning characteristics over differing terrain we will obtain identical observations over adjacent land and ocean regions during both clear air and thunderstorm periods comparing the electric field behavior over these various terrains. For this, a 3-meter NOAA buoy moored 20NM off the coast of the Kennedy Space Center was instrumented with an electric field mill and New Mexico Tech's slow antenna to measure the electric fields aloft and compared to the existing on-shore electric field mill suite of 31 sensors and a coastal slow antenna. New Mexico Tech's Lightning Mapping Array and the Eastern Range Cloud-to-Ground Lightning Surveillance System, along with the network of high-speed cameras being used to capture cloud-to-ground lightning strikes over the terrain regions to identify a valid data set and verify the electric fields. This is an on-going project with the potential for significant impact on the determination of lightning risk to objects on the ground. This presentation will provide results and instrumentation progress to date.

Synchronized observations of cloud-to-ground lightning using VHF broadband interferometer and acoustic arrays

NASA Astrophysics Data System (ADS)

Qiu, Shi; Zhou, Bi-Hua; Shi, Li-Hua

2012-10-01

A single-station-based lightning discharge channel reconstruction system by combining a two-dimensional (2D) VHF broadband interferometer and a three-dimensional (3D) acoustic lighting mapping system has been developed and used for lightning observations. Two cloud-to-ground (CG) flashes with highly branched leaders recorded by the system are analyzed and presented in this paper. VHF radiation could well delineate the development of simultaneous leader branches, while acoustic emissions mainly located on the main channel which was traversed by return stroke (RS) process. Localizations by VHF and acoustic emissions agree well with each other. The mapping results confirm that audible acoustic emission of lightning discharge is mainly associated with high current process like RS. Leaders could generate detectable acoustic signals, with amplitude at least an order weaker than ensuing RS, but they are hard to identify except in closer ranges than the main channel. As a significant phenomenon, this paper provides the first 3D locations associated with sources of tearing sounds, which are inferred to be generated by downward negative leaders when they approach ground. The synchronized observation enable VHF interferometer locate lightning development in spatially quasi 3D, and three stepped leaders, five dart leaders and two dart-stepped leaders are identified, with the 3D velocity (1.3-3.9) × 105 m/s, (1.0-2.9) × 107 m/s and from (1.0-1.3) × 107 m/s to (2.4-2.6) × 106 m/s, respectively. In addition, the application of this approach in improving the accuracy of thunder ranging is discussed.

Utilizing ISS Camera Systems for Scientific Analysis of Lightning Characteristics and comparison with ISS-LIS and GLM

NASA Astrophysics Data System (ADS)

Schultz, C. J.; Lang, T. J.; Leake, S.; Runco, M.; Blakeslee, R. J.

2017-12-01

Video and still frame images from cameras aboard the International Space Station (ISS) are used to inspire, educate, and provide a unique vantage point from low-Earth orbit that is second to none; however, these cameras have overlooked capabilities for contributing to scientific analysis of the Earth and near-space environment. The goal of this project is to study how georeferenced video/images from available ISS camera systems can be useful for scientific analysis, using lightning properties as a demonstration. Camera images from the crew cameras and high definition video from the Chiba University Meteor Camera were combined with lightning data from the National Lightning Detection Network (NLDN), ISS-Lightning Imaging Sensor (ISS-LIS), the Geostationary Lightning Mapper (GLM) and lightning mapping arrays. These cameras provide significant spatial resolution advantages ( 10 times or better) over ISS-LIS and GLM, but with lower temporal resolution. Therefore, they can serve as a complementarity analysis tool for studying lightning and thunderstorm processes from space. Lightning sensor data, Visible Infrared Imaging Radiometer Suite (VIIRS) derived city light maps, and other geographic databases were combined with the ISS attitude and position data to reverse geolocate each image or frame. An open-source Python toolkit has been developed to assist with this effort. Next, the locations and sizes of all flashes in each frame or image were computed and compared with flash characteristics from all available lightning datasets. This allowed for characterization of cloud features that are below the 4-km and 8-km resolution of ISS-LIS and GLM which may reduce the light that reaches the ISS-LIS or GLM sensor. In the case of video, consecutive frames were overlaid to determine the rate of change of the light escaping cloud top. Characterization of the rate of change in geometry, more generally the radius, of light escaping cloud top was integrated with the NLDN, ISS-LIS and GLM to understand how the peak rate of change and the peak area of each flash aligned with each lightning system in time. Flash features like leaders could be inferred from the video frames as well. Testing is being done to see if leader speeds may be accurately calculated under certain circumstances.

Lightning Jump Algorithm Development for the GOES·R Geostationary Lightning Mapper

NASA Technical Reports Server (NTRS)

Schultz. E.; Schultz. C.; Chronis, T.; Stough, S.; Carey, L.; Calhoun, K.; Ortega, K.; Stano, G.; Cecil, D.; Bateman, M.;

Verification of the WFAS Lightning Efficiency Map

Treesearch

Paul Sopko; Don Latham; Isaac Grenfell

2007-01-01

A Lightning Ignition Efficiency map was added to the suite of daily maps offered by the Wildland Fire Assessment System (WFAS) in 1999. This map computes a lightning probability of ignition (POI) based on the estimated fuel type, fuel depth, and 100-hour fuel moisture interpolated from the Remote Automated Weather Station (RAWS) network. An attempt to verify the...

Multicolor Photometric Observation of Lightning from Space: Comparison with Radio Measurements

NASA Technical Reports Server (NTRS)

Adachi, Toru; Cohen, Morris; Said, Ryan; Blakeslee, Richard J.; Cummer, Steven A.; Li, Jingbo; Lu, Geopeng; Hsu, Rue-Ron; Su, Han-Tzong; Chen, Alfred Bing-Chih;

An Investigation of the Kinematic and Microphysical Control of Lightning Rate, Extent and NOx Production using DC3 Observations and the NASA Lightning Nitrogen Oxides Model (LNOM)

NASA Technical Reports Server (NTRS)

Carey, Lawrence; Koshak, William; Peterson, Harold; Matthee, Retha; Bain, Lamont

2013-01-01

The Deep Convective Clouds and Chemistry (DC3) experiment seeks to quantify the relationship between storm physics, lightning characteristics and the production of nitrogen oxides via lightning (LNOx). The focus of this study is to investigate the kinematic and microphysical control of lightning properties, particularly those that may govern LNOx production, such as flash rate, type and extent across Alabama during DC3. Prior studies have demonstrated that lightning flash rate and type is correlated to kinematic and microphysical properties in the mixed-phase region of thunderstorms such as updraft volume and graupel mass. More study is required to generalize these relationships in a wide variety of storm modes and meteorological conditions. Less is known about the co-evolving relationship between storm physics, morphology and three-dimensional flash extent, despite its importance for LNOx production. To address this conceptual gap, the NASA Lightning Nitrogen Oxides Model (LNOM) is applied to North Alabama Lightning Mapping Array (NALMA) and Vaisala National Lightning Detection Network(TM) (NLDN) observations following ordinary convective cells through their lifecycle. LNOM provides estimates of flash rate, flash type, channel length distributions, lightning segment altitude distributions (SADs) and lightning NOx production profiles. For this study, LNOM is applied in a Lagrangian sense to multicell thunderstorms over Northern Alabama on two days during DC3 (21 May and 11 June 2012) in which aircraft observations of NOx are available for comparison. The LNOM lightning characteristics and LNOX production estimates are compared to the evolution of updraft and precipitation properties inferred from dual-Doppler and polarimetric radar analyses applied to observations from a nearby radar network, including the UAH Advanced Radar for Meteorological and Operational Research (ARMOR). Given complex multicell evolution, particular attention is paid to storm morphology, cell mergers and possible dynamical, microphysical and electrical interaction of individual cells when testing various hypotheses.

An Investigation of the Kinematic and Microphysical Control of Lightning Rate, Extent and NOX Production using DC3 Observations and the NASA Lightning Nitrogen Oxides Model (LNOM)

NASA Technical Reports Server (NTRS)

Carey, Lawrence; Koshak, William; Peterson, Harold; Matthee, Retha; Bain, Lamont

2013-01-01

The Deep Convective Clouds and Chemistry (DC3) experiment seeks to quantify the relationship between storm physics, lightning characteristics and the production of nitrogen oxides via lightning (LNOx). The focus of this study is to investigate the kinematic and microphysical control of lightning properties, particularly those that may govern LNOx production, such as flash rate, type and extent across Alabama during DC3. Prior studies have demonstrated that lightning flash rate and type is correlated to kinematic and microphysical properties in the mixed-phase region of thunderstorms such as updraft volume and graupel mass. More study is required to generalize these relationships in a wide variety of storm modes and meteorological conditions. Less is known about the co-evolving relationship between storm physics, morphology and three-dimensional flash extent, despite its importance for LNOx production. To address this conceptual gap, the NASA Lightning Nitrogen Oxides Model (LNOM) is applied to North Alabama Lightning Mapping Array (NALMA) and Vaisala National Lightning Detection NetworkTM (NLDN) observations following ordinary convective cells through their lifecycle. LNOM provides estimates of flash rate, flash type, channel length distributions, lightning segment altitude distributions (SADs) and lightning NOx production profiles. For this study, LNOM is applied in a Lagrangian sense to multicell thunderstorms over Northern Alabama on two days during DC3 (21 May and 11 June 2012) in which aircraft observations of NOx are available for comparison. The LNOM lightning characteristics and LNOX production estimates are compared to the evolution of updraft and precipitation properties inferred from dual-Doppler and polarimetric radar analyses applied to observations from a nearby radar network, including the UAH Advanced Radar for Meteorological and Operational Research (ARMOR). Given complex multicell evolution, particular attention is paid to storm morphology, cell mergers and possible dynamical, microphysical and electrical interaction of individual cells when testing various hypotheses.

WRF-Chem Simulations of Lightning-NOx Production and Transport in Oklahoma and Colorado Thunderstorms Observed During DC3

NASA Technical Reports Server (NTRS)

Cummings, Kristin A.; Pickering, Kenneth E.; Barth, M.; Bela, M.; Li, Y.; Allen, D.; Bruning, E.; MacGorman, D.; Rutledge, S.; Basarab, B.;

Small Negative Cloud-to-Ground Lightning Reports at the KSC-ER

NASA Technical Reports Server (NTRS)

Wilson, Jennifer G.; Cummins, Kenneth L.; Krider, E. Philip

2009-01-01

'1he NASA Kennedy Space Center (KSC) and Air Force Eastern Range (ER) use data from two cloud-to-ground (CG) lightning detection networks, the CGLSS and the NLDN, and a volumetric lightning mapping array, LDAR, to monitor and characterize lightning that is potentially hazardous to ground or launch operations. Data obtained from these systems during June-August 2006 have been examined to check the classification of small, negative CGLSS reports that have an estimated peak current, [I(sup p)] less than 7 kA, and to determine the smallest values of I(sup p), that are produced by first strokes, by subsequent strokes that create a new ground contact (NGC), and by subsequent strokes that remain in a pre-existing channel (PEC). The results show that within 20 km of the KSC-ER, 21% of the low-amplitude negative CGLSS reports were produced by first strokes, with a minimum I(sup p) of-2.9 kA; 31% were by NGCs, with a minimum I(sup p) of-2.0 kA; and 14% were by PECs, with a minimum I(sup p) of -2.2 kA. The remaining 34% were produced by cloud pulses or lightning events that we were not able to classify.

Lightning NOx Production and Transport in the 29 May 2012 DC3 case: A Modeling Study Using Radar Data Assimilation and a Branched Lightning Simulation.

NASA Astrophysics Data System (ADS)

Allen, B. J.; Mansell, E. R.; Betten, D.

2014-12-01

Open questions exist regarding chemical transport by convection and the sensitivity of Lightning Nitrogen Oxide (LNOx) production to flash type (IC vs. CG), channel height, and channel length. To help answer these and other questions, the Deep Convective Clouds and Chemistry (DC3) field project was conducted during the spring of 2012. On 29 May 2012, observations of an Oklahoma supercell were collected by two mobile SMART-R radars, the mobile NOXP radar, multiple NEXRAD radars, the Oklahoma Lightning Mapping Array (LMA), and the NSF/NCAR HIAPER and NASA DC-8 aircraft. In this study, data from the mobile and NEXRAD radars are assimilated into the NSSL COMMAS model using the Ensemble Kalman Filter, beginning shortly after initiation of convection and ending when the aircraft made their final measurements of the storm's outflow. The model analyses produce a realistic representation of the kinematic character of the storm throughout this time period. COMMAS includes the NSSL multimoment microphysics, explicit cloud electrification, and a branched lightning discharge scheme, which is used to produce LNOx within the model via a method dependent upon air pressure and lightning channel length. Model results will be presented and compared to radar, lightning, and aircraft observations. Of particular importance, the vertical distribution of lightning, channel length of lightning, and LNOx production and transport in the model will be analyzed and compared to LMA observations and anvil-level outflow observations from the aircraft. In addition, to examine entrainment and detrainment of air by the storm and to provide a check on LNOx production and transport, trajectory analyses will be presented and the transport of inert trace gases such as carbon monoxide in the model will be analyzed and compared to aircraft measurements.

Ground-Based Observations of Terrestrial Gamma Ray Flashes Associated with Downward-Directed Lightning Leaders

NASA Astrophysics Data System (ADS)

Belz, J.; Abbasi, R.; Krehbiel, P. R.; LeVon, R.; Remington, J.; Rison, W.; Thomas, R. J.

2017-12-01

Terrestrial Gamma Flashes (TGFs) have been observed in satellite-borne gamma ray detectors for several decades, starting with the BATSE instrument on the Compton Gamma-Ray observatory in 1994. TGFs consist of bursts of upwards of 1018 primary gamma rays, with a duration of up to a few milliseconds, originating in the Earth's atmosphere. More recent observations have shown that satellite-observed TGFs are generated in upward-propagating negative leaders of intracloud lightning, suggesting that they may be sensitive to the processes responsible for the initial lightning breakdown. Here, we present the first evidence that TGFs are also produced at the beginning of negative cloud-to-ground flashes, and that they may provide a new window through which ground-based observatories may contribute to understanding the breakdown process. The Telescope Array Surface Detector (TASD) is a 700 square kilometer cosmic ray observatory, an array of 507 3m2 scintillators on a 1.2 km grid. The array is triggered and read out when at least three adjacent detectors observe activity within an 8 μs window. Following the observation of bursts of anomalous TASD triggers, lasting a few hundred microseconds and correlated with local lightning activity, a Lightning Mapping Array (LMA) and slow electric field antenna were installed at the TASD site in order to study the effect. From data obtained between 2014 and 2016, correlated observations were obtained for ten -CG flashes. In 9 out of 10 cases, bursts of up to five anomalous triggers were detected during the first ms of the flash, as negative breakdown was descending into lower positive storm charge. The triggers occurred when the LMA-detected VHF radiation sources were at altitudes between 1.5 to 4.5 km AGL. The tenth flash was initiated by an unusually energetic leader that reached the ground in 2.5 ms and produced increasingly powerful triggers down to about 500 m AGL. While the TASD is not optimized for individual gamma ray detection and energy measurement, simulation studies indicate that the fluxes and forward-beaming observed are consistent with production in processes such as the relativistic runaway electron avalanche. We conclude that the anomalous triggers observed by TA are most likely downward-directed Terrestrial Gamma Flashes.

Automated analysis of lightning leader speed, local flash rates and electric charge structure in thunderstorms

NASA Astrophysics Data System (ADS)

Van Der Velde, O. A.; Montanya, J.; López, J. A.

2017-12-01

A Lightning Mapping Array (LMA) maps radio pulses emitted by lightning leaders, displaying lightning flash development in the cloud in three dimensions. Since the last 10 years about a dozen of these advanced systems have become operational in the United States and in Europe, often with the purpose of severe weather monitoring or lightning research. We introduce new methods for the analysis of complex three-dimensional lightning data produced by LMAs and illustrate them by cases of a mid-latitude severe weather producing thunderstorm and a tropical thunderstorm in Colombia. The method is based on the characteristics of bidrectional leader development as observed in LMA data (van der Velde and Montanyà, 2013, JGR-Atmospheres), where mapped positive leaders were found to propagate at characteristic speeds around 2 · 104 m s-1, while negative leaders typically propagate at speeds around 105 m s-1. Here, we determine leader speed for every 1.5 x 1.5 x 0.75 km grid box in 3 ms time steps, using two time intervals (e.g., 9 ms and 27 ms) and circles (4.5 km and 2.5 km wide) in which a robust Theil-Sen fitting of the slope is performed for fast and slow leaders. The two are then merged such that important speed characteristics are optimally maintained in negative and positive leaders, and labeled with positive or negative polarity according to the resulting velocity. The method also counts how often leaders from a lightning flash initiate or pass through each grid box. This "local flash rate" may be used in severe thunderstorm or NOx production studies and shall be more meaningful than LMA source density which is biased by the detection efficiency. Additionally, in each grid box the median x, y and z components of the leader propagation vectors of all flashes result in a 3D vector grid which can be compared to vectors in numerical models of leader propagation in response to cloud charge structure. Finally, the charge region altitudes, thickness and rates are summarized from vertical profiles of positive and negative leader rates where these exceed their 7-point averaged profiles. The summarized data can be used to follow charge structure evolution over time, and will be useful for climatological studies and statistical comparison against the parameters of the meteorological environment of storms.

The Kinematic and Microphysical Control of Lightning Rate, Extent and NOX Production

NASA Technical Reports Server (NTRS)

Carey, Lawrence; Koshak, William; Peterson, Harold; Matthee, Retha; Bain, A. Lamont

2014-01-01

The Deep Convective Clouds and Chemistry (DC3) experiment seeks to quantify the relationship between storm physics, lightning characteristics and the production of nitrogen oxides via lightning (LNOx). The focus of this study is to investigate the kinematic and microphysical control of lightning properties, particularly those that may govern LNOx production, such as flash rate, type and extent across Alabama during DC3. Prior studies have demonstrated that lightning flash rate and type is correlated to kinematic and microphysical properties in the mixed-phase region of thunderstorms such as updraft volume and graupel mass. More study is required to generalize these relationships in a wide variety of storm modes and meteorological conditions. Less is known about the co-evolving relationship between storm physics, morphology and three-dimensional flash extent, despite its importance for LNOx production. To address this conceptual gap, the NASA Lightning Nitrogen Oxides Model (LNOM) is applied to North Alabama Lightning Mapping Array (NALMA) and Vaisala National Lightning Detection Network(TM) (NLDN) observations following ordinary convective cells through their lifecycle. LNOM provides estimates of flash rate, flash type, channel length distributions, lightning segment altitude distributions (SADs) and lightning NOx production profiles. For this study, LNOM is applied in a Lagrangian sense to multicell thunderstorms over Northern Alabama on two days during DC3 (21 May and 11 June 2012) in which aircraft observations of NOx are available for comparison. The LNOM lightning characteristics and LNOX production estimates are compared to the evolution of updraft and precipitation properties inferred from dual-Doppler and polarimetric radar analyses applied to observations from a nearby radar network, including the UAH Advanced Radar for Meteorological and Operational Research (ARMOR). Given complex multicell evolution, particular attention is paid to storm morphology, cell mergers and possible dynamical, microphysical and electrical interaction of individual cells when testing various hypotheses.

Lightning channels emerging from the top of thunderstorm clouds

NASA Astrophysics Data System (ADS)

van der Velde, Oscar; Montanyà, Joan; Soula, Serge; Pineda, Nicolau

2013-04-01

In recent years, research of transient luminous events is shifting from the rather common elves and sprites high above thunderclouds to the much less frequently observed phenomena issued by the storm cloud itself: gigantic jets (GJ) connecting to the ionosphere, and high-energy terrestrial gamma-ray flashes (TGFs) recorded at spacecraft. These phenomena both are observed more often at tropical latitudes, and a link may or may not exist between the two. It is likely that both share the requirement of high-altitude leaders of negative polarity, which in the case of a GJ escapes from the cloud top and transforms into a long streamer discharge. While this should be easier at lower air densities (higher altitude), previous studies showed that GJs need not be produced by storms with the highest tops. TGFs have still unclear origins, but may be related to production in negative leaders or other regions with strong vertically directed electric fields by runaway electron mechnisms. In December 2009, a gigantic jet was observed in the Mediterranean Sea region. During the same night, a nearby storm produced repeatedly multiple leaders piercing through the cloud top, without any sign of streamers reaching higher altitudes (unlike jets or starters). Similar observations of upward cloud-to-air lightning have been obtained recently by low-light cameras over storms near the Catalonian coast in different seasons. The production conditions are currently being investigated, with a focus on optically determined altitudes of lightning and evolution of storm tops (and their temperature level). The initial impression is that cloud flashes escape into the air above during stages when the growing convective cloud top is very close to the main charge production region. Upward cloud-to-air lightning has also been mapped by the Ebro Lightning Mapping Array, exhibiting inverse bolt-from-the blue characteristics, and as a by-product of a bolt-from-the-blue lightning strike to ground, recorded by a high-speed camera.

Modeling Long-Distance ELF Radio Atmospherics Generated by Rocket-Triggered Lightning

NASA Astrophysics Data System (ADS)

Moore, R. C.; Kunduri, B.; Anand, S.; Dupree, N.; Mitchell, M.; Agrawal, D.

2010-12-01

This paper addresses the generation and propagation of radio atmospherics (sferics) radiated by lightning in order to assess the ability to infer the electrical properties of lightning from great distances. This ability may prove to greatly enhance the understanding of lightning processes that are associated with the production of transient luminous events (TLEs) as well as other ionospheric effects associated with lightning. The modeling of the sferic waveform is carried out using a modified version of the Long Wavelength Propagation Capability (LWPC) code developed by the Naval Ocean Systems Center over a period of many years. LWPC is an inherently narrowband propagation code that has been modified to predict the broadband response of the Earth-ionosphere waveguide to an impulsive lightning flash. Unlike other similar efforts, the modified code presented preserves the ability of LWPC to account for waveguide mode-coupling and to account for changes to the electrical properties of the ground and ionosphere along the propagation path. The effort described is conducted in advance of the deployment of a global extremely low frequency (ELF) magnetic field array, which is presently under construction. The global ELF array is centered on the International Center for Lightning Research and Testing (ICLRT) located at Camp Blanding, Florida. The ICLRT is well-known for conducting rocket-triggered lightning experiments over the last 15-20 years. This paper uses lightning current waveforms directly measured at the base of the lightning channel (observations performed at the ICLRT) as an input to the model to predict the sferic waveform to be observed by the array under various ionospheric conditions. An analysis of the predicted sferic waveforms is presented, and the components of the lightning current waveform that most effectively excite the Earth-ionosphere waveguide are identified.

Forecasting Lightning Threat using Cloud-resolving Model Simulations

NASA Technical Reports Server (NTRS)

McCaul, E. W., Jr.; Goodman, S. J.; LaCasse, K. M.; Cecil, D. J.

2009-01-01

As numerical forecasts capable of resolving individual convective clouds become more common, it is of interest to see if quantitative forecasts of lightning flash rate density are possible, based on fields computed by the numerical model. Previous observational research has shown robust relationships between observed lightning flash rates and inferred updraft and large precipitation ice fields in the mixed phase regions of storms, and that these relationships might allow simulated fields to serve as proxies for lightning flash rate density. It is shown in this paper that two simple proxy fields do indeed provide reasonable and cost-effective bases for creating time-evolving maps of predicted lightning flash rate density, judging from a series of diverse simulation case study events in North Alabama for which Lightning Mapping Array data provide ground truth. One method is based on the product of upward velocity and the mixing ratio of precipitating ice hydrometeors, modeled as graupel only, in the mixed phase region of storms at the -15\\dgc\\ level, while the second method is based on the vertically integrated amounts of ice hydrometeors in each model grid column. Each method can be calibrated by comparing domainwide statistics of the peak values of simulated flash rate proxy fields against domainwide peak total lightning flash rate density data from observations. Tests show that the first method is able to capture much of the temporal variability of the lightning threat, while the second method does a better job of depicting the areal coverage of the threat. A blended solution is designed to retain most of the temporal sensitivity of the first method, while adding the improved spatial coverage of the second. Weather Research and Forecast Model simulations of selected North Alabama cases show that this model can distinguish the general character and intensity of most convective events, and that the proposed methods show promise as a means of generating quantitatively realistic fields of lightning threat. However, because models tend to have more difficulty in correctly predicting the instantaneous placement of storms, forecasts of the detailed location of the lightning threat based on single simulations can be in error. Although these model shortcomings presently limit the precision of lightning threat forecasts from individual runs of current generation models, the techniques proposed herein should continue to be applicable as newer and more accurate physically-based model versions, physical parameterizations, initialization techniques and ensembles of cloud-allowing forecasts become available.

A Detailed Look at the Performance Characteristics of the Lightning Imaging Sensor

NASA Technical Reports Server (NTRS)

Zhang, Daile; Cummins, Kenneth L.; Bitzer, Phillip; Koshak, William J.

2018-01-01

The Lightning Imaging Sensor (LIS) on board the Tropical Rainfall Measuring Mission (TRMM) effectively reached its end of life on April 15, 2015 after 17+ years of observation. Given the wealth of information in the archived LIS lightning data, and growing use of optical observations of lightning from space throughout the world, it is still of importance to better understand LIS calibration and performance characteristics. In this work, we continue our efforts to quantify the optical characteristics of the LIS pixel array, and to further characterize the detection efficiency and location accuracy of LIS. The LIS pixel array was partitioned into four quadrants, each having its own signal amplifier and digital conversion hardware. In addition, the sensor optics resulted in a decreasing sensitivity with increasing displacement from the center of the array. These engineering limitations resulted in differences in the optical emissions detected across the pixel array. Our work to date has shown a 20% increase in the count of the lightning events detected in one of the LIS quadrants, because of a lower detection threshold. In this study, we will discuss our work in progress on these limitations, and their potential impact on the group- and flash-level parameters.

Physical and Dynamical Linkages Between Lightning Jumps and Storm Conceptual Models

NASA Technical Reports Server (NTRS)

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

2014-01-01

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

Integration of the Total Lightning Jump Algorithm into Current Operational Warning Environment Conceptual Models

NASA Technical Reports Server (NTRS)

Shultz, Christopher J.; Carey, Lawrence D.; Schultz, Elise V.; Stano, Geoffrey T.; Blakeslee, Richard J.; Goodman, Steven J.

2014-01-01

The presence and rates of total lightning are both correlated to and physically dependent upon storm updraft strength, mixed phase precipitation volume and the size of the charging zone. The updraft modulates the ingredients necessary for electrification within a thunderstorm, while the updraft also plays a critical role in the development of severe and hazardous weather. Therefore utilizing this relationship, the monitoring of lightning rates and jumps provides an additional piece of information on the evolution of a thunderstorm, more often than not, at higher temporal resolution than current operational radar systems. This correlation is the basis for the total lightning jump algorithm that has been developed in recent years. Currently, the lightning jump algorithm is being tested in two separate but important efforts. Schultz et al. (2014; AMS 10th Satellite Symposium) is exploring the transition of the algorithm from its research based formulation to a fully objective algorithm that includes storm tracking, Geostationary Lightning Mapper (GLM) Proxy data and the lightning jump algorithm. Chronis et al. (2014; this conference) provides context for the transition to current operational forecasting using lightning mapping array based products. However, what remains is an end to end physical and dynamical basis for relating lightning rates to severe storm manifestation, so the forecaster has a reason beyond simple correlation to utilize the lightning jump algorithm within their severe storm conceptual models. Therefore, the physical basis for the lightning jump algorithm in relation to severe storm dynamics and microphysics is a key component that must be further explored. Many radar studies have examined flash rates and their relation to updraft strength, updraft volume, precipitation-sized ice mass, etc.; however, relation specifically to lightning jumps is fragmented within the literature. Thus the goal of this study is to use multiple Doppler techniques to resolve the physical and dynamical storm characteristics specifically around the time of the lightning jump. This information will help forecasters anticipate lightning jump occurrence, or even be of use to determine future characteristics of a given storm (e.g., development of a mesocyclone, downdraft, or hail signature on radar), providing additional lead time/confidence in the severe storm warning paradigm.

Physical and Dynamical Linkages between Lightning Jumps and Storm Conceptual Models

NASA Technical Reports Server (NTRS)

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

2014-01-01

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

Kinematic and Microphysical Control of Lightning Flash Rate over Northern Alabama

NASA Technical Reports Server (NTRS)

Carey, Lawrence D.; Bain, Anthony L.; Matthee, Retha; Schultz, Christopher J.; Schultz, Elise V.; Deierling, Wiebke; Petersen, Walter A.

2015-01-01

The Deep Convective Clouds and Chemistry (DC3) experiment seeks to examine the relationship between deep convection and the production of nitrogen oxides (NO (sub x)) via lightning (LNO (sub x)). A critical step in estimating LNO (sub x) production in a cloud-resolving model (CRM) without explicit lightning is to estimate the flash rate from available model parameters that are statistically and physically correlated. As such, the objective of this study is to develop, improve and evaluate lightning flash rate parameterizations in a variety of meteorological environments and storm types using radar and lightning mapping array (LMA) observations taken over Northern Alabama from 2005-2012, including during DC3. UAH's Advanced Radar for Meteorological and Operational Research (ARMOR) and the Weather Surveillance Radar - 1988 Doppler (WSR 88D) located at Hytop (KHTX) comprises the dual-Doppler and polarimetric radar network, which has been in operation since 2004. The northern Alabama LMA (NA LMA) in conjunction with Vaisala's National Lightning Detection Network (NLDN) allow for a detailed depiction of total lightning during this period. This study will integrate ARMOR-KHTX dual Doppler/polarimetric radar and NA LMA lightning observations from past and ongoing studies, including the more recent DC3 results, over northern Alabama to form a large data set of 15-20 case days and over 20 individual storms, including both ordinary multicell and supercell convection. Several flash rate parameterizations will be developed and tested, including those based on 1) graupel/small hail volume; 2) graupel/small hail mass, and 3) convective updraft volume. Sensitivity of the flash rate parameterizations to storm intensity, storm morphology and environmental conditions will be explored.

Lightning discharges produced by wind turbines

NASA Astrophysics Data System (ADS)

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

2014-02-01

New observations with a 3-D Lightning Mapping Array and high-speed video are presented and discussed. The first set of observations shows that under certain thunderstorm conditions, wind turbine blades can produce electric discharges at regular intervals of 3 s in relation to its rotation, over periods of time that range from a few minutes up to hours. This periodic effect has not been observed in static towers indicating that the effect of rotation is playing a critical role. The repeated discharges can occur tens of kilometers away from electrically active thunderstorm areas and may or may not precede a fully developed upward lightning discharge from the turbine. Similar to rockets used for triggering lightning, the fast movement of the blade tip plays an important role on the initiation of the discharge. The movement of the rotor blades allows the tip to "runaway" from the generated corona charge. The second observation is an uncommon upward/downward flash triggered by a wind turbine. In that flash, a negative upward leader was initiated from a wind turbine without preceding lightning activity. The flash produced a negative cloud-to-ground stroke several kilometers from the initiation point. The third observation corresponds to a high-speed video record showing simultaneous upward positive leaders from a group of wind turbines triggered by a preceding intracloud flash. The fact that multiple leaders develop simultaneously indicates a poor shielding effect among them. All these observations provide some special features on the initiation of lightning by nonstatic and complex tall structures.

Smart CMOS image sensor for lightning detection and imaging.

PubMed

Rolando, Sébastien; Goiffon, Vincent; Magnan, Pierre; Corbière, Franck; Molina, Romain; Tulet, Michel; Bréart-de-Boisanger, Michel; Saint-Pé, Olivier; Guiry, Saïprasad; Larnaudie, Franck; Leone, Bruno; Perez-Cuevas, Leticia; Zayer, Igor

2013-03-01

We present a CMOS image sensor dedicated to lightning detection and imaging. The detector has been designed to evaluate the potentiality of an on-chip lightning detection solution based on a smart sensor. This evaluation is performed in the frame of the predevelopment phase of the lightning detector that will be implemented in the Meteosat Third Generation Imager satellite for the European Space Agency. The lightning detection process is performed by a smart detector combining an in-pixel frame-to-frame difference comparison with an adjustable threshold and on-chip digital processing allowing an efficient localization of a faint lightning pulse on the entire large format array at a frequency of 1 kHz. A CMOS prototype sensor with a 256×256 pixel array and a 60 μm pixel pitch has been fabricated using a 0.35 μm 2P 5M technology and tested to validate the selected detection approach.

Using Total Lightning Observations to Enhance Lightning Safety

NASA Technical Reports Server (NTRS)

Stano, Geoffrey T.

2012-01-01

Lightning is often the underrated threat faced by the public when it comes to dangerous weather phenomena. Typically, larger scale events such as floods, hurricanes, and tornadoes receive the vast majority of attention by both the general population and the media. This comes from the fact that these phenomena are large, longer lasting, can impact a large swath of society at one time, and are dangerous events. The threat of lightning is far more isolated on a case by case basis, although millions of cloud-to-ground lightning strikes hit this United States each year. While attention is given to larger meteorological events, lightning is the second leading cause of weather related deaths in the United States. This information raises the question of what steps can be taken to improve lightning safety. Already, the meteorological community s understanding of lightning has increased over the last 20 years. Lightning safety is now better addressed with the National Weather Service s access to the National Lightning Detection Network data and enhanced wording in their severe weather warnings. Also, local groups and organizations are working to improve public awareness of lightning safety with easy phrases to remember, such as "When Thunder Roars, Go Indoors." The impacts can be seen in the greater array of contingency plans, from airports to sports stadiums, addressing the threat of lightning. Improvements can still be made and newer technologies may offer new tools as we look towards the future. One of these tools is a network of sensors called a lightning mapping array (LMA). Several of these networks exist across the United States. NASA s Short-term Prediction Research and Transition Center (SPoRT), part of the Marshall Spaceflight Center, has access to three of these networks from Huntsville, Alabama, the Kennedy Space Center, and Washington D.C. The SPoRT program s mission is to help transition unique products and observations into the operational forecast environment. SPoRT has been collaborating with the Huntsville National Weather Service (NWS) Office since 2003 and has since included several other offices to better implement LMA observations into real-time applications. Much of that work has focused on the LMA s ability to detect intra-cloud lightning in addition to cloud-to-ground lightning strikes. Combined, these observations are called total lightning. With total lightning observations, NWS offices can enhance their situational awareness and improve severe weather warnings. Just as importantly, the observed intra-cloud flashes often precede the first cloud-to-ground strike by a few minutes. SPoRT and its partner NWS offices are working to develop visualizations and applications to better utilize these data. However, there is a drawback. The LMAs have a short range of no more than 200 km. This is being addressed with the next generation geostationary satellite, GOES-R, which will boast the Geostationary Lightning Mapper (GLM). SPoRT, in conjunction with NOAA s GOES-R Proving Ground, is working to prepare the end user community for the GLM era using the LMA observations as a demonstration tool. Working collaboratively with our NWS partners, SPoRT is working to determine how best to integrate these future observations to improve both severe storm warnings and lightning safety.

Exploring the Use of Radar for a Physically Based Lightning Cessation Nowcasting Tool

NASA Technical Reports Server (NTRS)

Schultz, Elise V.; Petersen, Walter A.; Carey, Lawrence D.

2011-01-01

NASA s Marshall Space Flight Center (MSFC) and the University of Alabama in Huntsville (UAHuntsville) are collaborating with the 45th Weather Squadron (45WS) at Cape Canaveral Air Force Station (CCAFS) to enable improved nowcasting of lightning cessation. This project centers on use of dual-polarimetric radar capabilities, and in particular, the new C-band dual-polarimetric weather radar acquired by the 45WS. Special emphasis is placed on the development of a physically based operational algorithm to predict lightning cessation. While previous studies have developed statistically based lightning cessation algorithms, we believe that dual-polarimetric radar variables offer the possibility to improve existing algorithms through the inclusion of physically meaningful trends reflecting interactions between in-cloud electric fields and hydrometeors. Specifically, decades of polarimetric radar research using propagation differential phase has demonstrated the presence of distinct phase and ice crystal alignment signatures in the presence of strong electric fields associated with lightning. One question yet to be addressed is: To what extent can these ice-crystal alignment signatures be used to nowcast the cessation of lightning activity in a given storm? Accordingly, data from the UAHuntsville Advanced Radar for Meteorological and Operational Research (ARMOR) along with the NASA-MSFC North Alabama Lightning Mapping Array are used in this study to investigate the radar signatures present before and after lightning cessation. Thus far, our case study results suggest that the negative differential phase shift signature weakens and disappears after the analyzed storms ceased lightning production (i.e., after the last lightning flash occurred). This is a key observation because it suggests that while strong electric fields may still have been present, the lightning cessation signature encompassed the period of the polarimetric negative phase shift signature. To the extent this behavior is repeatable in other cases, even if only in a substantial fraction of those cases, the case analyses suggests that differential propagation phase may prove to be a useful parameter for future lightning cessation algorithms. Indeed, analysis of 15+ cases has shown additional indications of the weakening and disappearance of this ice alignment signature with lightning cessation. A summary of results will be presented.

Characterization of infrasound from lightning

NASA Astrophysics Data System (ADS)

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

2008-08-01

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

Determination of a Limited Scope Network's Lightning Detection Efficiency

NASA Technical Reports Server (NTRS)

Rompala, John T.; Blakeslee, R.

2008-01-01

This paper outlines a modeling technique to map lightning detection efficiency variations over a region surveyed by a sparse array of ground based detectors. A reliable flash peak current distribution (PCD) for the region serves as the technique's base. This distribution is recast as an event probability distribution function. The technique then uses the PCD together with information regarding: site signal detection thresholds, type of solution algorithm used, and range attenuation; to formulate the probability that a flash at a specified location will yield a solution. Applying this technique to the full region produces detection efficiency contour maps specific to the parameters employed. These contours facilitate a comparative analysis of each parameter's effect on the network's detection efficiency. In an alternate application, this modeling technique gives an estimate of the number, strength, and distribution of events going undetected. This approach leads to a variety of event density contour maps. This application is also illustrated. The technique's base PCD can be empirical or analytical. A process for formulating an empirical PCD specific to the region and network being studied is presented. A new method for producing an analytical representation of the empirical PCD is also introduced.

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

NASA Technical Reports Server (NTRS)

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 the promising aspects and challenges encountered in utilizing objective tracking and GLM proxy data, as well as recent results that demonstrate the value added information gained by combining the lightning jump concept with traditional meteorological measurements.

An Evaluation of Lightning Flash Rate Parameterizations Based on Observations of Colorado Storms during DC3

NASA Astrophysics Data System (ADS)

Basarab, B.; Fuchs, B.; Rutledge, S. A.

2013-12-01

Predicting lightning activity in thunderstorms is important in order to accurately quantify the production of nitrogen oxides (NOx = NO + NO2) by lightning (LNOx). Lightning is an important global source of NOx, and since NOx is a chemical precursor to ozone, the climatological impacts of LNOx could be significant. Many cloud-resolving models rely on parameterizations to predict lightning and LNOx since the processes leading to charge separation and lightning discharge are not yet fully understood. This study evaluates predicted flash rates based on existing lightning parameterizations against flash rates observed for Colorado storms during the Deep Convective Clouds and Chemistry Experiment (DC3). Evaluating lightning parameterizations against storm observations is a useful way to possibly improve the prediction of flash rates and LNOx in models. Additionally, since convective storms that form in the eastern plains of Colorado can be different thermodynamically and electrically from storms in other regions, it is useful to test existing parameterizations against observations from these storms. We present an analysis of the dynamics, microphysics, and lightning characteristics of two case studies, severe storms that developed on 6 and 7 June 2012. This analysis includes dual-Doppler derived horizontal and vertical velocities, a hydrometeor identification based on polarimetric radar variables using the CSU-CHILL radar, and insight into the charge structure using observations from the northern Colorado Lightning Mapping Array (LMA). Flash rates were inferred from the LMA data using a flash counting algorithm. We have calculated various microphysical and dynamical parameters for these storms that have been used in empirical flash rate parameterizations. In particular, maximum vertical velocity has been used to predict flash rates in some cloud-resolving chemistry simulations. We diagnose flash rates for the 6 and 7 June storms using this parameterization and compare to observed flash rates. For the 6 June storm, a preliminary analysis of aircraft observations of storm inflow and outflow is presented in order to place flash rates (and other lightning statistics) in the context of storm chemistry. An approach to a possibly improved LNOx parameterization scheme using different lightning metrics such as flash area will be discussed.

Development of Tactical Lightning Avoidance Product for Terminal Weather Support

NASA Astrophysics Data System (ADS)

Yoshikawa, E.; Yoshida, S.; Adachi, T.; Kusunoki, K.; Ushio, T.

2015-12-01

Aircraft initiated or intercepted lightning is one of significant issues for civilian flight operation in Japan. It is much less possible than the past that lightning strikes cause fatal aircraft accidents thanks to both of certifications of aircraft design for lightning strikes and many of weather supports for aircraft operation. However, hundreds of lightning strikes to aircrafts have still been reported in each recent year in Japan, and airlines have been forced to delay or cancel most of those flights and to cost several hundred millions of yen for repair. Especially, lightning discharges during winter in the coastal area of the Sea of Japan frequently cause heavy damages on aircrafts due to their large charge transfer. It is important in actual aircraft operation that observed meteorological parameters are converted to decision-making information. Otherwise, pilots, controllers, or operators need to learn meteorology as much as weather experts, and to owe hard work load to interpret observed meteorological data to their risk. Ideally, it is desired to automatically provide them with predicted operation risk, for example, delay time, possibility of flight cancellation, and repair cost caused by lightning.Our research group has just started development of tactical lightning avoidance product, where a risk index of an aircraft operation due to lightning is calculated mainly from three novel observation devices: The phased array weather radar has potential to detect thunderstorms in their early stage due to the high volume scan rate of 10 - 30 sec. A lightning mapping system, such as Broadband Observation network for Lightning and Thunderstorm, indicates electrical structure inside clouds in concert with a co-located radar data. Aircraft sounding and real-time data downlink, especially high-frequency data provided by Secondary Surveillance Radar mode S, gives in-situ measurements of wind and temperature. Especially the in-situ temperature data can indicate altitudes of electrical charge separation. An integrated data processing method to output the tactical lightning avoidance product will be developed by analyzing data obtained in an observation campaign which will have been conducted until 2017. In the presentation, overview and progress of our research and development will be described.

Further Research on the Electrification of Pyrocumulus Clouds

NASA Technical Reports Server (NTRS)

Lang, Timothy J.; Laroche, Kendell; Baum, Bryan; Bateman, Monte; Mach, Douglas

2015-01-01

Past research on pyrocumulus electrification has demonstrated that a variety of lightning types can occur, including cloud-to-ground (CG) flashes, sometimes of dominant positive polarity, as well as small intra-cloud (IC) discharges in the upper levels of the pyro-cloud. In Colorado during summer 2012, the first combined polarimetric radar, multi-Doppler radar, and three-dimensional lightning mapping array (LMA) observations of lightning-producing pyrocumulus were obtained. These observations suggested that the National Lightning Detection Network (NLDN) was not sensitive enough to detect the small IC flashes that appear to be the dominant mode of lightning in these clouds. However, after an upgrade to the network in late 2012, the NLDN began detecting some of this pyrocumulus lightning. Multiple pyrocumulus clouds documented by the University of Wisconsin for various fires in 2013 and 2014 (including over the Rim, West Fork Complex, Yarnell Hill, Hardluck, and several other incidents) are examined and reported on here. This study exploits the increased-sensitivity NLDN as well as the new nationwide U.S. network of polarimetric Next-generation Radars (NEXRADs). These observations document the common occurrence of a polarimetric "dirty ice" signature - modest reflectivities (20-40+ dBZ), near-zero differential reflectivity, and reduced correlation coefficient (less than 0.9) - prior to the production of lightning. This signature is indicative of a mixture of ash and ice particles in the upper levels of the pyro-cloud (less than -20 C), with the ice interpreted as being necessary for pyro-cloud electrification. Pseudo-Geostationary Lightning Mapper (GLM) data will be produced from the 2012 LMA observations, and the ability of GLM to detect small pyrocumulus ICs will be assessed. The utility of lightning and polarimetric radar for documenting rapid wildfire growth, as well as for documenting pyrocumulus impacts on the composition of the upper troposphere/lower stratosphere (UTLS), will be discussed.

Large Charge Moment Change Lightning in an Oklahoma Mesoscale Convective System

NASA Technical Reports Server (NTRS)

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.

Oceanic Storm Characteristics off the Kennedy Space Center Coast

NASA Technical Reports Server (NTRS)

Wilson, J. G.; Simpson, A. A.; Cummins, K. L.; Kiriazes, J. J.; Brown, R. G.; Mata, C. T.

2014-01-01

Natural cloud-to-ground lightning may behave differently depending on the characteristics of the attachment mediums, including the peak current (inferred from radiation fields) and the number of ground strike locations per flash. Existing literature has raised questions over the years on these characteristics of lightning over oceans, and the behaviors are not yet well understood. To investigate this we will obtain identical electric field observations over adjacent land and ocean regions during both clear air and thunderstorm periods. Oceanic observations will be obtained using a 3-meter NOAA buoy that has been instrumented with a Campbell Scientific electric field mill and New Mexico Techs slow antenna, to measure the electric fields aloft. We are currently obtaining measurements from this system on-shore at the Florida coast, to calibrate and better understand the behavior of the system in elevated-field environments. Sometime during winter 2013, this system will be moored 20NM off the coast of the Kennedy Space Center. Measurements from this system will be compared to the existing on-shore electric field mill suite of 31 sensors and a coastal slow antenna. Supporting observations will be provided by New Mexico Techs Lightning Mapping Array, the Eastern Range Cloud to Ground Lightning Surveillance System, and the National Lightning Detection Network. An existing network of high-speed cameras will be used to capture cloud-to-ground lightning strikes over the terrain regions to identify a valid data set for analysis. This on-going project will demonstrate the value of off-shore electric field measurements for safety-related decision making at KSC, and may improve our understanding of relative lightning risk to objects on the ground vs. ocean. This presentation will provide an overview of this new instrumentation, and a summary of our progress to date.

Large Charge Moment Change Lightning in an Oklahoma Mesoscale Convective System

NASA Technical Reports Server (NTRS)

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

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 (> 75 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 polarimetric data from individual radars, 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.

A Wrf-Chem Flash Rate Parameterization Scheme and LNO(x) Analysis of the 29-30 May 2012 Convective Event in Oklahoma During DC3

NASA Technical Reports Server (NTRS)

Cummings, Kristin A.; Pickering, Kenneth E.; Barth, M.; Weinheimer, A.; Bela, M.; Li, Y.; Allen, D.; Bruning, E.; MacGorman, D.; Rutledge, S.;

A WRF-Chem Flash Rate Parameterization Scheme and LNOx Analysis of the 29-30 May 2012 Convective Event in Oklahoma During DC3

NASA Technical Reports Server (NTRS)

Cummings, Kristin A.; Pickering, Kenneth E.; Barth, M.; Weinheimer, A.; Bela, M.; Li, Y.; Allen, D.; Bruning, E.; MacGorman, D.; Rutledge, S.;

The NASA Severe Thunderstorm Observations and Regional Modeling (NASA STORM) Project

NASA Technical Reports Server (NTRS)

Schultz, Christopher J.; Gatlin, Patrick N.; Lang, Timothy J.; Srikishen, Jayanthi; Case, Jonathan L.; Molthan, Andrew L.; Zavodsky, Bradley T.; Bailey, Jeffrey; Blakeslee, Richard J.; Jedlovec, Gary J.

2016-01-01

The NASA Severe Storm Thunderstorm Observations and Regional Modeling(NASA STORM) project enhanced NASA’s severe weather research capabilities, building upon existing Earth Science expertise at NASA Marshall Space Flight Center (MSFC). During this project, MSFC extended NASA’s ground-based lightning detection capacity to include a readily deployable lightning mapping array (LMA). NASA STORM also enabled NASA’s Short-term Prediction and Research Transition (SPoRT) to add convection allowing ensemble modeling to its portfolio of regional numerical weather prediction (NWP) capabilities. As a part of NASA STORM, MSFC developed new open-source capabilities for analyzing and displaying weather radar observations integrated from both research and operational networks. These accomplishments enabled by NASA STORM are a step towards enhancing NASA’s capabilities for studying severe weather and positions them for any future NASA related severe storm field campaigns.

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

NASA Technical Reports Server (NTRS)

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

2002-01-01

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

GOES-R Proving Ground Activities at the NASA Short-Term Prediction Research and Transition (SPoRT) Center

NASA Technical Reports Server (NTRS)

Molthan, Andrew

2011-01-01

SPoRT is actively involved in GOES-R Proving Ground activities in a number of ways: (1) Applying the paradigm of product development, user training, and interaction to foster interaction with end users at NOAA forecast offices national centers. (2) Providing unique capabilities in collaboration with other GOES-R Proving Ground partners (a) Hybrid GOES-MODIS imagery (b) Pseudo-GLM via regional lightning mapping arrays (c) Developing new RGB imagery from EUMETSAT guidelines

Flash propagation and inferred charge structure relative to radar-observed ice alignment signatures in a small Florida mesoscale convective system

NASA Astrophysics Data System (ADS)

Biggerstaff, Michael I.; Zounes, Zackery; Addison Alford, A.; Carrie, Gordon D.; Pilkey, John T.; Uman, Martin A.; Jordan, Douglas M.

2017-08-01

A series of vertical cross sections taken through a small mesoscale convective system observed over Florida by the dual-polarimetric SMART radar were combined with VHF radiation source locations from a lightning mapping array (LMA) to examine the lightning channel propagation paths relative to the radar-observed ice alignment signatures associated with regions of negative specific differential phase (KDP). Additionally, charge layers inferred from analysis of LMA sources were related to the ice alignment signature. It was found that intracloud flashes initiated near the upper zero-KDP boundary surrounding the negative KDP region. The zero-KDP boundary also delineated the propagation path of the lightning channel with the negative leaders following the upper boundary and positive leaders following the lower boundary. Very few LMA sources were found in the negative KDP region. We conclude that rapid dual-polarimetric radar observations can diagnose strong electric fields and may help identify surrounding regions of charge.

Exploring the Use of Radar for Physically-Based Nowcasting of Lightning Cessation

NASA Technical Reports Server (NTRS)

Schultz, Elise V.; Petersen, Walter A.; Carey, Lawrence D.

2011-01-01

NASA's Marshall Space Flight Center and the University of Alabama in Huntsville (UAHuntsville) are collaborating with the 45th Weather Squadron (45WS) at Cape Canaveral Air Force Station (CCAFS) to enable improved nowcasting of lightning cessation. This project centers on use of dual-polarimetric radar capabilities, and in particular, the new C-band dual polarimetric weather radar acquired by the 45WS. Special emphasis is placed on the development of a physically-based operational algorithm to predict lightning cessation. While previous studies have developed statistically based lightning cessation algorithms driven primarily by trending in the actual total lightning flash rate, we believe that dual polarimetric radar variables offer the possibility to improve existing algorithms through the inclusion of physically meaningful trends reflecting interactions between in-cloud electric fields and ice-microphysics. Specifically, decades of polarimetric radar research using propagation differential phase has demonstrated the presence of distinct phase and ice crystal alignment signatures in the presence of strong electric fields associated with lightning. One question yet to be addressed is: To what extent can propagation phase-based ice-crystal alignment signatures be used to nowcast the cessation of lightning activity in a given storm? Accordingly, data from the UAHuntsville Advanced Radar for Meteorological and Operational Research (ARMOR) along with the NASA-MSFC North Alabama Lightning Mapping Array are used in this study to investigate the radar signatures present before and after lightning cessation. Thus far our case study results suggest that the negative differential phase shift signature weakens and disappears after the analyzed storms ceased lightning production (i.e., after the last lightning flash occurred). This is a key observation because it suggests that while strong electric fields may still have been present, the lightning cessation signature was encompassed in the period of the polarimetric negative phase shift signature. To the extent this behavior is repeatable in other cases, even if only in a substantial fraction of those cases, the analysis suggests that differential propagation phase may prove to be a useful parameter for future lightning cessation algorithms. Indeed, a preliminary analysis of 15+ cases has shown additional indications of the weakening and disappearance of this ice alignment signature with lightning cessation. A summary of these case-study results is presented.

Observations of a bi-directional lightning leader producing an M-component

NASA Astrophysics Data System (ADS)

Kotovsky, D. A.; Uman, M. A.; Wilkes, R.; Carvalho, F. L.; Jordan, D. M.

2017-12-01

Lightning discharges to ground often exhibit millisecond-scale surges in the continuing currents following return strokes, called M-components. Relatively little is known regarding the source of M-component charge and the mechanisms by which that charge is transferred to ground. In this work, we seek to directly address these questions by presenting correlated high-speed video and Lightning Mapping Array (LMA) observations of a bi-directional leader that resulted in an M-component occurring in a rocket-and-wire triggered lightning flash. The observed leader initiated in the decayed remnants of a positive leader channel that had traversed virgin air approximately 90 msec prior. Three-dimensional locations and speeds of the photographed bi-directional leader and M-component processes are calculated by mapping video images to the observed LMA channel geometry. Both ends of the bi-directional leader exhibited speeds on the order of 2 x106 m sec-1 over 570 meters of the visible channel. Propagation of the luminosity wave from the in-cloud leader to ground ( 8.8 km channel length) exhibited appreciable dispersion, with rise-times (10-90%) increasing from 330 to 410 μsec and pulse-widths (half-maximum) increasing from 380 to 810 μsec - the M-component current pulse measured at ground-level exhibited a rise-time of 290 μsec and a pulse-width of 770 μsec. Group velocities of the luminosity wave have been calculated as a function of frequency, increasing from 2 x107 to 6 x107 m sec-1 over the dominant signal bandwidth (DC to 2 kHz). Additionally, multiple waves of luminosity are observed within the in-cloud channel, indicating nuanced wave phenomena possibly associated with reflection from the end of the leader channel and attachment with the main lightning channel carrying continuing current to ground.

Variability of electromagnetic signatures of lightning initiation observed in the West Mediterranean basin

NASA Astrophysics Data System (ADS)

Kolmasova, I.; Santolik, O.; Defer, E.; Stéphane, P.; Lan, R.; Uhlir, L.; Coquillat, S.; Lambert, D.; Pinty, J. P.; Prieur, S.

2016-12-01

Lightning discharges to ground often exhibit millisecond-scale surges in the continuing currents following return strokes, called M-components. Relatively little is known regarding the source of M-component charge and the mechanisms by which that charge is transferred to ground. In this work, we seek to directly address these questions by presenting correlated high-speed video and Lightning Mapping Array (LMA) observations of a bi-directional leader that resulted in an M-component occurring in a rocket-and-wire triggered lightning flash. The observed leader initiated in the decayed remnants of a positive leader channel that had traversed virgin air approximately 90 msec prior. Three-dimensional locations and speeds of the photographed bi-directional leader and M-component processes are calculated by mapping video images to the observed LMA channel geometry. Both ends of the bi-directional leader exhibited speeds on the order of 2 x106 m sec-1 over 570 meters of the visible channel. Propagation of the luminosity wave from the in-cloud leader to ground ( 8.8 km channel length) exhibited appreciable dispersion, with rise-times (10-90%) increasing from 330 to 410 μsec and pulse-widths (half-maximum) increasing from 380 to 810 μsec - the M-component current pulse measured at ground-level exhibited a rise-time of 290 μsec and a pulse-width of 770 μsec. Group velocities of the luminosity wave have been calculated as a function of frequency, increasing from 2 x107 to 6 x107 m sec-1 over the dominant signal bandwidth (DC to 2 kHz). Additionally, multiple waves of luminosity are observed within the in-cloud channel, indicating nuanced wave phenomena possibly associated with reflection from the end of the leader channel and attachment with the main lightning channel carrying continuing current to ground.

Very High Frequency Radio Emissions Associated With the Production of Terrestrial Gamma-Ray Flashes

NASA Astrophysics Data System (ADS)

Lyu, Fanchao; Cummer, Steven A.; Krehbiel, Paul R.; Rison, William; Briggs, Michael S.; Cramer, Eric; Roberts, Oliver; Stanbro, Matthew

2018-02-01

Recent studies of the close association between terrestrial gamma-ray flashes (TGFs) production and simultaneous lightning processes have shown that many TGFs are produced during the initial leader of intracloud flashes and that some low-frequency (LF) radio emissions may directly come from TGF itself. Measurements of any simultaneous very high frequency (VHF) radio emissions would give important insight into any lightning leader dynamics that are associated with TGF generation, and thus, such measurements are needed. Here we report on coordinated observations of TGFs detected simultaneously by Fermi Gamma-ray Burst Monitor, two VHF lightning mapping arrays, and Duke ground-based LF radio sensors to investigate more on the close association between TGFs and LF and VHF radio emissions. Three TGFs are analyzed here and confirm previous findings on the close association between TGF generation and lightning processes and, for the first time, provide time-aligned measurements of the VHF radio signature within a few tens of microseconds of TGF generation. Strong VHF emissions were observed essentially simultaneously with two TGFs and within a few tens of microseconds of a third TGF. Equally importantly, the VHF measurement details indicate that the TGF-associated emissions are nonimpulsive and extended in time. We conclude that the TGF-producing process is at least sometimes closely associated with strong VHF emissions, and thus, there may be a link between the generation of TGFs and active lightning streamer dynamics.

Map of low-frequency electromagnetic noise in the sky

NASA Astrophysics Data System (ADS)

Füllekrug, Martin; Mezentsev, Andrew; Watson, Robert; Gaffet, Stéphane; Astin, Ivan; Smith, Nathan; Evans, Adrian

2015-06-01

The Earth's natural electromagnetic environment is disturbed by anthropogenic electromagnetic noise. Here we report the first results from an electromagnetic noise survey of the sky. The locations of electromagnetic noise sources are mapped on the hemisphere above a distributed array of wideband receivers that operate in a small aperture configuration. It is found that the noise sources can be localized at elevation angles up to ˜60° in the sky, well above the horizon. The sky also exhibits zones with little or no noise that are found toward the local zenith and the southwest of the array. These results are obtained by a rigorous analysis of the residuals from the classic dispersion relation for electromagnetic waves using an array analysis of electric field measurements in the frequency range from ˜20 to 250 kHz. The observed locations of the noise sources enable detailed observations of ionospheric modification, for example, caused by particle precipitation and lightning discharges, while the observed exclusion zones enable the detection of weak natural electromagnetic emissions, for example, from streamers in transient luminous events above thunderclouds.

An Operational Perspective of Total Lightning Information

NASA Technical Reports Server (NTRS)

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

2009-01-01

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

A Comparison of Cloud-to-Ground Lightning Characteristics and Observations from Multiple Networks and Videos during the 31 May 2013 El Reno, OK Tornadic Supercell Storm

NASA Astrophysics Data System (ADS)

Kuhlman, K. M.; Coy, J.; Seimon, A.

2015-12-01

Cloud-to-ground (CG) lightning flashes recorded by both the National Lightning Detection Network (NLDN) and Earth Networks Total Lightning Network (ENTLN) are compared with three-dimensional lightning mapping observations from the Oklahoma Lightning Mapping Array (OKLMA) and storm chaser video recorded of the 31 May 2013 El Reno tornadic supercell. The El Reno Survey Project (El-Reno-Survey.net) was created to crowd-source the abundance of storm chaser video from this event and provide open-access to the scientific community of the data. An initial comparison of CG lightning flashes captured on these videos with CG data from NLDN revealed a disagreement on the total number of flashes, with NLDN recording many negative CG flashes at lower peak amplitude not apparent in any of the videos. For this study, the area of the comparison was expanded to include the entire storm and data from both the ENTLN and LMA were added to compare the observations from each network in terms of timestamp, location detection, peak current, and polarity of each flash in the period 2230-2330 UTC. An initial comparison of 557 matched NLDN and ENLTN CG flashes, indicated predominately negative polairy CG flashes (58% NLDN/77% ENI) throughout the storm during this period. However, after a 15 kA peak current filter was applied, the NLDN indicated primarily positive polarity (84% +CG) while ENTLN still indicated primarily negative polarity (77% -CG) for the 264 remaining matched flashes. Before the filter was applied, the average distance between the two networks for the same flash was more than 2 km, but improved to approximately 1 km after the 15 kA filter was applied, likely removing some misidentified cloud flashes of uncertain location. This misclassification of IC flashes as CG at low peak current amplitudes for both networks is further evident when compared to video and the OKLMA data. Additionally, the charge analysis of OKLMA flashes revealed the NLDN-determined positive-polarity as correct every time the NLDN and ENTLN disagreed. For the 2013 El Reno supercell storm, there appears to be a major flaw in the ENTLN's ability to determine the polarity of CG flashes despite having roughly similar peak current magnitudes and location for most CG flash occurrences as the NLDN.

Atmospheric electricity/meteorology analysis

NASA Technical Reports Server (NTRS)

Goodman, Steven J.; Blakeslee, Richard; Buechler, Dennis

1993-01-01

This activity focuses on Lightning Imaging Sensor (LIS)/Lightning Mapper Sensor (LMS) algorithm development and applied research. Specifically we are exploring the relationships between (1) global and regional lightning activity and rainfall, and (2) storm electrical development, physics, and the role of the environment. U.S. composite radar-rainfall maps and ground strike lightning maps are used to understand lightning-rainfall relationships at the regional scale. These observations are then compared to SSM/I brightness temperatures to simulate LIS/TRMM multi-sensor algorithm data sets. These data sets are supplied to the WETNET project archive. WSR88-D (NEXRAD) data are also used as it becomes available. The results of this study allow us to examine the information content from lightning imaging sensors in low-earth and geostationary orbits. Analysis of tropical and U.S. data sets continues. A neural network/sensor fusion algorithm is being refined for objectively associating lightning and rainfall with their parent storm systems. Total lightning data from interferometers are being used in conjunction with data from the national lightning network. A 6-year lightning/rainfall climatology has been assembled for LIS sampling studies.

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

NASA Technical Reports Server (NTRS)

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

2005-01-01

Each morning, the forecasters at the National Weather Service in Melbourn, FL (NWS MLB) produce an experimental cloud-to-ground (CG) lightning threat index map for their county warning area (CWA) that is posted to their web site (http://www.srh.weather.gov/mlb/ghwo/lightning.shtml) . Given the hazardous nature of lightning in central Florida, especially during the warm season months of May-September, these maps help users factor the threat of lightning, relative to their location, into their daily plans. The maps are color-coded in five levels from Very Low to Extreme, with threat level definitions based on the probability of lightning occurrence and the expected amount of CG activity. On a day in which thunderstorms are expected, there are typically two or more threat levels depicted spatially across the CWA. The locations of relative lightning threat maxima and minima often depend on the position and orientation of the low-level ridge axis, forecast propagation and interaction of sea/lake/outflow boundaries, expected evolution of moisture and stability fields, and other factors that can influence the spatial distribution of thunderstorms over the CWA. The lightning threat index maps are issued for the 24-hour period beginning at 1200 UTC (0700 AM EST) each day with a grid resolution of 5 km x 5 km. Product preparation is performed on the AWIPS Graphical Forecast Editor (GFE), which is the standard NWS platform for graphical editing. Currently, the forecasters create each map manually, starting with a blank map. To improve efficiency of the forecast process, NWS MLB requested that the Applied Meteorology Unit (AMU) create gridded warm season lightning climatologies that could be used as first-guess inputs to initialize lightning threat index maps. The gridded values requested included CG strike densities and frequency of occurrence stratified by synoptic-scale flow regime. The intent is to increase consistency between forecasters while enabling them to focus on the mesoscale detail of the forecast, ultimately benefiting the end-users of the product. Several studies took place at the Florida State University (FSU) and NWS Tallahassee (TAE) for which they created daily flow regimes using Florida 1200 UTC synoptic soundings and CG strike densities from National Lightning Detection Network (NLDN) data. The densities were created on a 2.5 km x 2.5 km grid for every hour of every day during the warm seasons in the years 1989-2004. The grids encompass an area that includes the entire state of Florida and adjacent Atlantic and Gulf of Mexico waters. Personnel at the two organizations provided this data and supporting software for the work performed by the AMU. The densities were first stratified by flow regime, then by time in 1-, 3-, 6-, 12-, and 24-hour increments while maintaining the 2.5 km x 2.5 km grid resolution. A CG frequency of occurrence was calculated for each stratification and grid box by counting the number of days with lightning and dividing by the total number of days in the data set. New CG strike densities were calculated for each stratification and grid box by summing the strike number values over all warm seasons, then normalized by dividing the summed values by the number of lightning days. This makes the densities conditional on whether lightning occurred. The frequency climatology values will be used by forecasters as proxy inputs for lightning prObability, while the density climatology values will be used for CG amount. In addition to the benefits outlined above, these climatologies will provide improved temporal and spatial resolution, expansion of the lightning threat area to include adjacent coastal waters, and potential to extend the forecast to include the day-2 period. This presentation will describe the lightning threat index map, discuss the work done to create the maps initialized with climatological guidance, and show examples of the climatological CG lightning densities and frequencies of occurren based on flow regime.

The Kinematic and Microphysical Control of Storm Integrated Lightning Flash Extent

NASA Technical Reports Server (NTRS)

Carey, Lawrence; Koshak, William; Petersen, Harold; Schultz, Elise; Schultz, Chris; Matthee, Retha; Bain, Lamont

2012-01-01

The objective of this preliminary study is to investigate the kinematic and microphysical control of lightning properties, particularly those that may govern the production of nitrogen oxides (NOx) in thunderstorms, such as flash rate, type and extent. The mixed-phase region is where the noninductive charging (NIC) process is thought to generate most storm electrification during rebounding collisions between ice particles in the presence of supercooled water. As a result, prior radar-based studies have demonstrated that lightning flash rate is well correlated to kinematic and microphysical properties in the mixed-phase region of thunderstorms such as updraft volume, graupel mass, or ice mass flux. There is also some evidence that lightning type is associated with the convective state. Intracloud (IC) lightning tends to dominate during the updraft accumulation of precipitation ice mass while cloud-to-ground (CG) lightning is more numerous during the downdraft-driven descent of radar echo associated with graupel and hail. More study is required to generalize these relationships, especially regarding lightning type, in a wide variety of storm modes and meteorological conditions. Less is known about the co-evolving relationship between storm kinematics, microphysics, morphology and three-dimensional flash extent, despite its importance for lightning NOx production. To address this conceptual gap, the NASA MSFC Lightning Nitrogen Oxides Model (LNOM) is applied to North Alabama Lightning Mapping Array (NALMA) and Vaisala National Lightning Detection NetworkTM (NLDN) observations following ordinary convective cells through their lifecycle. LNOM provides estimates of flash type, channel length distributions, lightning segment altitude distributions (SADs) and lightning NOx production profiles. For this study, LNOM is applied in a Lagrangian sense to well isolated convective cells on 3 April 2007 (single cell and multi-cell hailstorm, non-severe multicell) and 6 July 2007 (non-severe multi-cell) over Northern Alabama. The LNOM lightning characteristics are compared to the evolution of updraft and precipitation properties inferred from dual-Doppler and polarimetric radar analyses applied to observations from a nearby Doppler radar network, including the UA Huntsville Advanced Radar for Meteorological and Operational Research (ARMOR, C-band, polarimetric). The LNOM estimated SAD and lightning NOx production profiles are placed in the context of radar derived profiles of vertical motion, precipitation types and amounts. Finally, these analyses are used to determine if storm integrated flash channel extent is as well correlated to volumetric updraft and precipitation ice characteristics in the mixed phase region as flash rate for these individual convective cells.

Using Flow Regime Lightning and Sounding Climatologies to Initialize Gridded Lightning Threat Forecasts for East Central Florida

NASA Technical Reports Server (NTRS)

Lambert, Winifred; Short, David; Wolkmer, Matthew; Sharp, David; Spratt, Scott

2006-01-01

Each morning, the forecasters at the National Weather Service in Melbourne, FL (NWS MLB) produce an experimental cloud-to-ground (CG) lightning threat index map for their county warning area (CWA) that is posted to their web site (http://www.srh.weather.gov/mlb/ghwo/lightning.shtml) . Given the hazardous nature of lightning in East Central Florida, especially during the warm season months of May September, these maps help users factor the threat of lightning, relative to their location, into their daily plans. The maps are color-coded in five levels from Very Low to Extreme, with threat level definitions based on the probability of lightning occurrence and the expected amount of CG activity. On a day in which thunderstorms are expected, there are typically two or more threat levels depicted spatially across the CWA. The locations of relative lightning threat maxima and minima often depend on the position and orientation of the low-level ridge axis, forecast propagation and interaction of sea/lake/outflow boundaries, expected evolution of moisture and stability fields, and other factors that can influence the spatial distribution of thunderstorms over the CWA. The lightning threat index maps are issued for the 24-hour period beginning at 1200 UTC each day with a grid resolution of 5 km x 5 km. Product preparation is performed on the AWIPS Graphical Forecast Editor (GFE), which is the standard NWS platform for graphical editing. Currently, the forecasters create each map manually, starting with a blank map. To improve efficiency of the forecast process, NWS MLB requested that the Applied Meteorology Unit (AMU) create gridded warm season lightning climatologies that could be used as first-guess inputs to initialize lightning threat index maps. The gridded values requested included CG strike densities and frequency of occurrence stratified by synoptic-scale flow regime. The intent is to improve consistency between forecasters while allowing them to focus on the mesoscale detail of the forecast, ultimately benefiting the end-users of the product. Several studies took place at the Florida State University (FSU) and NWS Tallahassee (TAE) in which they created daily flow regimes using Florida 1200 UTC synoptic soundings and CG strike densities, or number of strikes per specified area. The soundings used to determine the flow regimes were taken at Miami (MIA), Tampa (TBW), and Jacksonville (JAX), FL, and the lightning data for the strike densities came from the National Lightning Detection Network (NLDN). The densities were created on a 2.5 km x 2.5 km grid for every hour of every day during the warm seasons in the years 1989-2004. The grids encompass an area that includes the entire state of Florida and adjacent Atlantic and Gulf of Mexico waters. Personnel at FSU and NWS TAE provided this data and supporting software for the work performed by the AMU.

Using Flow Regime Lightning and Sounding Climatologies to Initialize Gridded Lightning Threat Forecasts for East Central Florida

NASA Technical Reports Server (NTRS)

Lambert, Winifred; Short, David; Volkmer, Matthew; Sharp, David; Spratt, Scott

2007-01-01

Each morning, the forecasters at the National Weather Service in Melbourne, FL (NWS MLB) produce an experimental cloud-to-ground (CG) lightning threat index map for their county warning area (CWA) that is posted to their web site (httl://www.srh.weather.gov/mlb/ghwo/lightning.shtml) . Given the hazardous nature of lightning in East Central Florida, especially during the warm season months of May September, these maps help users factor the threat of lightning, relative to their location, into their daily plans. The maps are color-coded in five levels from Very Low to Extreme, with threat level definitions based on the probability of lightning occurrence and the expected amount of CG activity. On a day in which thunderstorms are expected, there are typically two or more threat levels depicted spatially across the CWA. The locations of relative lightning threat maxima and minima often depend on the position and orientation of the low-level ridge axis, forecast propagation and interaction of sea/lake/outflow boundaries, expected evolution of moisture and stability fields, and other factors that can influence the spatial distribution of thunderstorms over the CWA. The lightning threat index maps are issued for the 24-hour period beginning at 1200 UTC each day with a grid resolution of 5 km x 5 km. Product preparation is performed on the AWIPS Graphical Forecast Editor (GFE), which is the standard NWS platform for graphical editing. Until recently, the forecasters created each map manually, starting with a blank map. To improve efficiency of the forecast process, NWS MLB requested that the Applied Meteorology Unit (AMU) create gridded warm season lightning climatologies that could be used as first-guess inputs to initialize lightning threat index maps. The gridded values requested included CG strike densities and frequency of occurrence stratified by synoptic-scale flow regime. The intent was to improve consistency between forecasters while allowing them to focus on the mesoscale detail of the forecast. Several studies took place at the Florida State University (FSU) and NWS Tallahassee (TAE) in which they created daily flow regimes using Florida 1200 UTC synoptic soundings and CG strike densities, or number of strikes per specified area. The soundings used to determine the flow regimes were taken at Miami (MIA), Tampa (TBW), and Jacksonville (JAX), FL, and the lightning data for the strike densities came from the National Lightning Detection Network (NLDN). The densities were created on a 2.5 km x 2.5 km grid for every hour of every day during the warm seasons in the years 1989-2004. The grids encompass an area that includes the entire state of Florida and adjacent Atlantic and Gulf of Mexico waters. Personnel at FSU and NWS TAE provided this data and supporting software for the work performed by the AMU.

First images of thunder: Acoustic imaging of triggered lightning

NASA Astrophysics Data System (ADS)

Dayeh, M. A.; Evans, N. D.; Fuselier, S. A.; Trevino, J.; Ramaekers, J.; Dwyer, J. R.; Lucia, R.; Rassoul, H. K.; Kotovsky, D. A.; Jordan, D. M.; Uman, M. A.

2015-07-01

An acoustic camera comprising a linear microphone array is used to image the thunder signature of triggered lightning. Measurements were taken at the International Center for Lightning Research and Testing in Camp Blanding, FL, during the summer of 2014. The array was positioned in an end-fire orientation thus enabling the peak acoustic reception pattern to be steered vertically with a frequency-dependent spatial resolution. On 14 July 2014, a lightning event with nine return strokes was successfully triggered. We present the first acoustic images of individual return strokes at high frequencies (>1 kHz) and compare the acoustically inferred profile with optical images. We find (i) a strong correlation between the return stroke peak current and the radiated acoustic pressure and (ii) an acoustic signature from an M component current pulse with an unusual fast rise time. These results show that acoustic imaging enables clear identification and quantification of thunder sources as a function of lightning channel altitude.

High speed imaging, lightning mapping arrays and thermal imaging: a synergy for the monitoring of electrical discharges at the onset of volcanic explosions

NASA Astrophysics Data System (ADS)

Gaudin, Damien; Cimarelli, Corrado; Behnke, Sonja; Cigala, Valeria; Edens, Harald; McNutt, Stefen; Smith, Cassandra; Thomas, Ronald; Van Eaton, Alexa

2017-04-01

Volcanic lightning is being increasingly studied, due to its great potential for the detection and monitoring of ash plumes. Indeed, it is observed in a large number of ash-rich volcanic eruptions and it produces electromagnetic waves that can be detected remotely in all weather conditions. Electrical discharges in volcanic plume can also significantly change the structural, chemical and reactivity properties of the erupted material. Although electrical discharges are detected in various regions of the plume, those happening at the onset of an explosion are of particular relevance for the early warning and the study of volcanic jet dynamics. In order to better constrain the electrical activity of young volcanic plumes, we deployed at Sakurajima (Japan) in 2015 a multiparametric set-up including: i) a lightning mapping array (LMA) of 10 VHF antennas recording the electromagnetic waves produced by lightning at a sample rate of 25 Msps; ii) a visible-light high speed camera (5000 frames per second, 0.5 m pixel size, 300 m field of view) shooting short movies (approx. duration 1 s) at different stages of the plume evolution, showing the location of discharges in relation to the plume; and iii) a thermal camera (25 fps, 1.5 m pixel size, 800 m field of view) continuously recording the plume and allowing the estimation of its main source parameters (volume, rise velocity, mass eruption rate). The complementarity of these three setups is demonstrated by comparing and aggregating the data at various stages of the plume development. In the earliest stages, the high speed camera spots discrete small discharges, that appear on the LMA data as peaks superimposed to the continuous radio frequency (CRF) signal. At later stages, flashes happen less frequently and increase in length. The correspondence between high speed camera and LMA data allows to define a direct correlation between the length of the flash and the intensity of the electromagnetic signal. Such correlation is used to estimate the evolution of the total discharges within a volcanic plume, while the superimposition of thermal and high speed videos allows to contextualize the flashes location in the scope of the plume features and dynamics.

Correlating the electrification of volcanic plumes with ashfall textures at Sakurajima Volcano, Japan

NASA Astrophysics Data System (ADS)

Smith, Cassandra M.; Van Eaton, Alexa R.; Charbonnier, Sylvain; McNutt, Stephen R.; Behnke, Sonja A.; Thomas, Ronald J.; Edens, Harald E.; Thompson, Glenn

2018-06-01

Volcanic lightning detection has become a useful resource for monitoring remote, under-instrumented volcanoes. Previous studies have shown that the behavior of volcanic plume electrification responds to changes in the eruptive processes and products. However, there has not yet been a study to quantify the links between ash textures and plume electrification during an actively monitored eruption. In this study, we examine a sequence of vulcanian eruptions from Sakurajima Volcano in Japan to compare ash textural properties (grain size, shape, componentry, and groundmass crystallinity) to plume electrification using a lightning mapping array and other monitoring data. We show that the presence of the continual radio frequency (CRF) signal is more likely to occur during eruptions that produce large seismic amplitudes (>7 μm) and glass-rich volcanic ash with more equant particle shapes. We show that CRF is generated during energetic, impulsive eruptions, where charge buildup is enhanced by secondary fragmentation (milling) as particles travel out of the conduit and into the gas-thrust region of the plume. We show that the CRF signal is influenced by a different electrification process than later volcanic lightning. By using volcanic CRF and lightning to better understand the eruptive event and its products these key observations will help the monitoring community better utilize volcanic electrification as a method for monitoring and understanding ongoing explosive eruptions.

Single Station System and Method of Locating Lightning Strikes

NASA Technical Reports Server (NTRS)

Medelius, Pedro J. (Inventor); Starr, Stanley O. (Inventor)

2003-01-01

An embodiment of the present invention uses a single detection system to approximate a location of lightning strikes. This system is triggered by a broadband RF detector and measures a time until the arrival of a leading edge of the thunder acoustic pulse. This time difference is used to determine a slant range R from the detector to the closest approach of the lightning. The azimuth and elevation are determined by an array of acoustic sensors. The leading edge of the thunder waveform is cross-correlated between the various acoustic sensors in the array to determine the difference in time of arrival, AT. A set of AT S is used to determine the direction of arrival, AZ and EL. The three estimated variables (R, AZ, EL) are used to locate a probable point of the lightning strike.

The Washington DC Metro Area Lightning Mapping Array

NASA Technical Reports Server (NTRS)

Krehbiel, Paul; Rison, William; Edens, Harald; OConnor, Nicholas; Aulich, Graydon; Thomas, Ronald; Kieft, Sandra; Goodman, Steven; Blakeslee, Richard; Hall, John;

Inversion of Acoustic and Electromagnetic Recordings for Mapping Current Flow in Lightning Strikes

NASA Astrophysics Data System (ADS)

Anderson, J.; Johnson, J.; Arechiga, R. O.; Thomas, R. J.

2012-12-01

Acoustic recordings can be used to map current-carrying conduits in lightning strikes. Unlike stepped leaders, whose very high frequency (VHF) radio emissions have short (meter-scale) wavelengths and can be located by lightning-mapping arrays, current pulses emit longer (kilometer-scale) waves and cannot be mapped precisely by electromagnetic observations alone. While current pulses are constrained to conductive channels created by stepped leaders, these leaders often branch as they propagate, and most branches fail to carry current. Here, we present a method to use thunder recordings to map current pulses, and we apply it to acoustic and VHF data recorded in 2009 in the Magdalena mountains in central New Mexico, USA. Thunder is produced by rapid heating and expansion of the atmosphere along conductive channels in response to current flow, and therefore can be used to recover the geometry of the current-carrying channel. Toward this goal, we use VHF pulse maps to identify candidate conductive channels where we treat each channel as a superposition of finely-spaced acoustic point sources. We apply ray tracing in variable atmospheric structures to forward model the thunder that our microphone network would record for each candidate channel. Because multiple channels could potentially carry current, a non-linear inversion is performed to determine the acoustic source strength of each channel. For each combination of acoustic source strengths, synthetic thunder is modeled as a superposition of thunder signals produced by each channel, and a power envelope of this stack is then calculated. The inversion iteratively minimizes the misfit between power envelopes of recorded and modeled thunder. Because the atmospheric sound speed structure through which the waves propagate during these events is unknown, we repeat the procedure on many plausible atmospheres to find an optimal fit. We then determine the candidate channel, or channels, that minimizes residuals between synthetic and acoustic recordings. We demonstrate the usefulness of this method on both intracloud and cloud-to-ground strikes, and discuss factors affecting our ability to replicate recorded thunder.

The Meteorology of Storms that Produce Narrow Bipolar Events

NASA Technical Reports Server (NTRS)

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.

Lightning Mapping Observations: What we are learning.

NASA Astrophysics Data System (ADS)

Krehbiel, P.

2001-12-01

The use of radio frequency time-of-arrival techniques for accurately mapping lightning discharges is revolutionizing our ability to study lightning discharge processes and to investigate thunderstorms. Different types of discharges are being observed that we have not been able to study before or knew existed. Included are a variety of inverted and normal polarity intracloud and cloud-to-ground discharges, frequent short-duration discharges at high altitude in storms and in overshooting convective tops, highly energetic impulsive discharge events, and horizontally extensive `spider' lightning discharges in large mesoscale convective systems. High time resolution measurements valuably complement interferometric observations and are starting to exceed the ability of interferometers to provide detailed pictures of flash development. Mapping observations can be used to infer the polarity of the breakdown channels and hence the location and sign of charge regions in the storm. The lightning activity in large, severe storms is found to be essentially continuous and volume-filling, with substantially more lightning inside the storm than between the cloud and ground. Spectacular dendritic structures are observed in many flashes. The lightning observations can be used to infer the electrical structure of a storm and therefore to study the electrification processes. The results are raising fundamental questions about how storms become electrified and how the electrification evolves with time. Supercell storms are commonly observed to electrify in an inverted or anomalous manner, raising questions about how these storms are different from normal storms, and even what is `normal'. The high lightning rates in severe storms raises the distinct possibility that the discharges themselves might be sustaining or enhancing the electrification. Correlated observations with radar, instrumented balloons and aircraft, and ground-based measurements are leading to greatly improved understanding of the electrical processes in storms. The mapping observations also provide possible diagnostics of storm type and severity. Lightning `holes' are observed as storms intensify and are robust indicators of strong updrafts and precursors of tornadic activity. Lightning in overshooting convective tops provides another indicator of strong convective surges and a valuable precursor of severity. The lightning observations show the locations of convective cores in storms and can be obtained in real time to monitor and track convective activity, much like meteorological radar. Mapping systems are able to passively detect and track aircraft flying through ice crystal clouds, as well as airborne or ground-based instruments or vehicles carrying active transmitters. Finally, the mapping techniques could readily be adapted to monitor noise and detect faults on power transmission lines.

Fifty Years of Lightning Observations from Space

NASA Astrophysics Data System (ADS)

Christian, H. J., Jr.

2017-12-01

Some of the earliest satellites, starting with OSO (1965), ARIEL (1967), and RAE (1968), detected lightning using either optical and RF sensors, although that was not their intent. One of the earliest instruments designed to detect lightning was the PBE (1977). The use of space to study lightning activity has exploded since these early days. The advent of focal-plane imaging arrays made it possible to develop high performance optical lightning sensors. Prior to the use of charged-coupled devices (CCD), most space-based lightning sensors used only a few photo-diodes, which limited the location accuracy and detection efficiency (DE) of the instruments. With CCDs, one can limit the field of view of each detector (pixel), and thus improve the signal to noise ratio over single-detectors that summed the light reflected from many clouds with the lightning produced by a single cloud. This pixelization enabled daytime DE to increase from a few percent to close to 90%. The OTD (1995), and the LIS (1997), were the first lightning sensors to utilize focal-plane arrays. Together they detected global lightning activity for more than twenty years, providing the first detailed information on the distribution of global lightning and its variability. The FORTE satellite was launched shortly after LIS, and became the first dedicated satellite to simultaneously measure RF and optical lightning emissions. It too used a CCD focal plane to detect and locate lightning. In November 2016, the GLM became the first lightning instrument in geostationary orbit. Shortly thereafter, China placed its GLI in orbit. Lightning sensors in geostationary orbit significantly increase the value of space-based observations. For the first time, lightning activity can be monitored continuously, over large areas of the Earth with high, uniform DE and location accuracy. In addition to observing standard lightning, a number of sensors have been placed in orbit to detect transient luminous events and tropospheric gamma-ray flashes. A lineal history of space-based lightning observations will be presented as well as a discussion of the scientific contributions made possible by these instruments. In addition, relative merits of space versus ground measurements will be addressed, as well as an effort to demonstrate the complementary nature of the two approaches.

Why does negative CG lightning have subsequent return strokes?

NASA Astrophysics Data System (ADS)

Wilkes, R. A.; Kotovsky, D. A.; Uman, M. A.; Carvalho, F. L.; Jordan, D.

2017-12-01

It is not understood why cloud-to-ground (CG) lightning flashes lowering negative charge often produce discrete dart-leader/return-stroke sequences rather than having the first stroke drain the available cloud charge, as is almost always the case for CG lightning lowering positive charge. Triggered lightning data obtained at the International Center for Lightning Research and Testing (ICLRT) in north-central Florida have been analyzed to clarify the subsequent return-stroke process. In summers 2013 through 2016 at the ICLRT, 53% of the rocket launches did not initiate any part of a lightning flash, 13% of the rocket launches created an initial stage only (ISO) and failed to produce a following dart-leader/return-stroke sequences, and 34% of rocket launches produced an initial stage (IS) followed by return strokes. The IS of the triggered lightning consists of the upward positive leader and a following initial continuing current, both being responsible for transporting negative charge from the cloud to ground. Our ISO events may well have some commonality with the roughly 20 percent of natural CG flashes that fail to produce a dart-leader/return-stroke. We have analyzed the IS of 41 triggered lightning flashes with (19 cases) and without (22 cases) following return strokes and compared areas and heights of the flash using data collected by a Lightning Mapping Array (LMA). In our preliminary analysis, we can find no geometrical feature of the lightning channel during the IS that will predict the occurrence or lack of occurrence of following return strokes. We also have compared the triggered-lightning electrical current and charge transfer observed at the ground. We found that the average current, duration, and charge transfer during the IS for ISO events is each about half that of ISs analyzed which are followed by dart-leader/return-stroke sequences, contrary to the results presented from the GCOELD in China. Summarizing, there appear to be no differences in the channel geometry between initial stages that do or do not yield dart-leader/return-stroke sequences. In contrast, we find that particular electrical characteristics of the initial stage may indicate whether or not a dart-leader/return-stroke sequence may follow, potentially shedding light on the physical processes necessary for dart-leader initiation.

Three Dimensional Lightning Launch Commit Criteria Visualization Tool

NASA Technical Reports Server (NTRS)

Bauman, William H., III

2014-01-01

Lightning occurrence too close to a NASA LSP or future SLS program launch vehicle in flight would have disastrous results. The sensitive electronics on the vehicle could be damaged to the point of causing an anomalous flight path and ultimate destruction of the vehicle and payload.According to 45th Weather Squadron (45 WS) Lightning Launch Commit Criteria (LLCC), a vehicle cannot launch if lightning is within 10 NM of its pre-determined flight path. The 45 WS Launch Weather Officers (LWOs) evaluate this LLCC for their launch customers to ensure the safety of the vehicle in flight. Currently, the LWOs conduct a subjective analysis of the distance between lightning and the flight path using data from different display systems. A 3-D display in which the lightning data and flight path are together would greatly reduce the ambiguity in evaluating this LLCC. It would give the LWOs and launch directors more confidence in whether a GO or NO GO for launch should be issued. When lightning appears close to the path, the LWOs likely err on the side of conservatism and deem the lightning to be within 10 NM. This would cause a costly delay or scrub. If the LWOs can determine with a strong level of certainty that the lightning is beyond 10 NM, launch availability would increase without compromising safety of the vehicle, payload or, in the future, astronauts.The AMU was tasked to conduct a market research of commercial, government, and open source software that might be able to ingest and display the 3-D lightning data from the KSC Lightning Mapping Array (LMA), the 45th Space Wing Weather Surveillance Radar (WSR), the National Weather Service in Melbourne Weather Surveillance Radar 1988 Doppler (WSR-88D), and the vehicle flight path data so that all can be visualized together. To accomplish this, the AMU conducted Internet searches for potential software candidates and interviewed software developers.None of the available off-the-shelf software had a 3-D capability that could display all of the data in a single visualization. The AMU determined there are two viable software packages that could satisfy the 45 WS requirement with further development and recommends the KSC Weather Office follow-up with both organizations to request development costs.

Large charge moment change lightning on 31 May to 1 June 2013, including the El Reno tornadic storm

NASA Astrophysics Data System (ADS)

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

2015-04-01

On 31 May 2013, a line of severe tornadic thunderstorms (the El Reno event) developed during the local afternoon in central Oklahoma, USA. Within range of the Oklahoma Lightning Mapping Array, the evolution of the event can be separated into three distinct periods: an Early period (before 02:00 UTC on 1 June) when the storm consisted of discrete supercells, a Middle period (02:00-05:00 UTC) when the convection began merging into a linear feature and stratiform precipitation developed, and a Late period (after 05:00 UTC) featuring a mature mesoscale convective system (MCS). Each of these periods demonstrated distinct patterns in the large (>100 C km) charge moment change (CMC) lightning that was produced. During the Early period, large-CMC positive cloud-to-ground (+CG) lightning was produced in the convective cores of supercells. These flashes were small in area (typically <500 km2) and were commonly associated with a sloping midlevel positive charge region in the echo overhang on the storm's forward flank. The Middle period featured a population of larger +CMCs (>500 km2, >300 C km) in the developing stratiform, similar to typical sprite-parent lightning in MCSs. During the Late period, convective large CMC +CGs ceased and instead large-CMC negative CGs were produced in and near the MCS convection. These flashes neutralized charge both in convection as well as in adjacent stratiform and anvil precipitation. The results suggest that the CMC metric has potential applications for studying tropospheric weather.

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

NASA Astrophysics Data System (ADS)

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

2018-01-01

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

How Lightning Works Inside Thunderstorms: A Half-Century of Lightning Studies

NASA Astrophysics Data System (ADS)

Krehbiel, P. R.

2015-12-01

Lightning is a fascinating and intriguing natural phenomenon, but the most interesting parts of lightning discharges are inside storms where they are obscured from view by the storm cloud. Although clouds are essentially opaque at optical frequencies, they are fully transparent at radio frequencies (RF). This, coupled with the fact that lightning produces prodigious RF emissions, has allowed us to image and study lightning inside storms using various RF and lower-frequency remote sensing techniques. As in all other scientific disciplines, the technology for conducting the studies has evolved to an incredible extent over the past 50 years. During this time, we have gone from having very little or no knowledge of how lightning operates inside storms, to being able to 'see' its detailed structure and development with an increasing degree of spatial and temporal resolution. In addition to studying the discharge processes themselves, lightning mapping observations provide valuable information on the electrical charge structure of storms, and on the mechanisms by which storms become strongly electrified. In this presentation we briefly review highlights of previous observations, focussing primarily on the long string of remote-sensing studies I have been involved in. We begin with the study of lightning charge centers of cloud-to-ground discharges in central New Mexico in the late 1960s and continue up to the present day with interferometric and 3-dimensional time-of-arrival VHF mapping observations of lightning in normally- and anomalously electrified storms. A particularly important aspect of the investigations has been comparative studies of lightning in different climatological regimes. We conclude with observations being obtained by a high-speed broadband VHF interferometer, which show in unprecedented detail how individual lightning discharges develop inside storms. From combined interferometer and 3-D mapping data, we are beginning to unlock nature's secrets concerning mysterious, high-power discharges known as narrow bipolar events (NBEs) and, more importantly, the long-standing question of how lightning is initiated inside storms.

Cochlear implantation for severe sensorineural hearing loss caused by lightning.

PubMed

Myung, Nam-Suk; Lee, Il-Woo; Goh, Eui-Kyung; Kong, Soo-Keun

2012-01-01

Lightning strike can produce an array of clinical symptoms and injuries. It may damage multiple organs and cause auditory injuries ranging from transient hearing loss and vertigo to complete disruption of the auditory system. Tympanic-membrane rupture is relatively common in patients with lightning injury. The exact pathogenetic mechanisms of auditory lesions in lightning survivors have not been fully elucidated. We report the case of a 45-year-old woman with bilateral profound sensorineural hearing loss caused by a lightning strike, who was successfully rehabilitated after a cochlear implantation. Copyright © 2012 Elsevier Inc. All rights reserved.

Lightning mapper sensor design study

NASA Technical Reports Server (NTRS)

Eaton, L. R.; Poon, C. W.; Shelton, J. C.; Laverty, N. P.; Cook, R. D.

1983-01-01

World-wide continuous measurement of lightning location, intensity, and time during both day and night is to be provided by the Lightning Mapper (LITMAP) instrument. A technology assessment to determine if the LITMAP requirements can be met using existing sensor and electronic technologies is presented. The baseline concept discussed in this report is a compromise among a number of opposing requirements (e.g., ground resolution versus array size; large field of view versus narrow bandpass filter). The concept provides coverage for more than 80 percent of the lightning events as based on recent above-cloud NASA/U2 lightning measurements.

LOFAR for lightning-interferometery and mapping

NASA Astrophysics Data System (ADS)

Scholten, Olaf; Buitink, Stijn; trinh, Gia; Bonardi, Antonio; Corstanje, Arthur; Ebert, Ute; Falcke, Heino; Hoerandel, Joerg; Mitra, Pragati; Mulrey, Katherine; Nelles, Anna; Rachen, Joerg; Rossetto, Laura; Rutjes, Casper; Schellart, Pim; Thoudam, Satayendra; ter Veen, Sander; Winchen, Tobias; Hare, Brian

2017-04-01

We show that a new observation mode at the Low Frequency Array (LOFAR) for Lightning-Interferometery and Mapping (LIM) allows for lightning observations with a resolution that is at least an order of magnitude better than presently operating Lightning Napping Arrays LMAs. Furthermore the polarization of the signal can be used to reconstruct the direction of the discharge. LOFAR, consisting of many thousands of antennas, is a digital radio telescope, primarily build for astronomy observations. The Low Band Antennas (LBA) we use for this work are sensitive to the frequency range of 10 - 90 MHz and consist of two inverted V-shaped dipoles. The antennas are grouped in stations consisting of 48 LBA spread over an area with a diameter of about 30 m for which the relative timing is known accurately. The LOFAR core of approximately 2 km diameter contains 24 such stations located near Exloo in the north of The Netherlands. Remote stations for LIM may lie at a distance of 100 km from the core. Signals are sampled at 200 MS/s (sampling time of 5 ns). All antennas are equipped with ring buffers, that store the raw voltage traces for up to 5 s. When a trigger is received, for example with a lightning flash, the ring buffers are frozen and their contents are copied over the network to a central storage location. We will show an initial analysis of data taken on June 19, 2013, for a thunderstorm at a distance of some 50 km from the telescope. The source location and emission time for each event (lightning step) is found by fitting the arrival times of the pulses for each separate antenna adjusting the station offsets, keeping them the same for all events. The fit reproduces the measurements with an accuracy of about 1 time sample. Interestingly much fine structure is seen in the time-traces and examples will be shown for some events. The time traces for antennas in different stations are very similar and thus not due to noise. We also see a clear polarization-dependent structure for the pulse. The strongly linearly polarized nature of the pulses is corroborated by model calculations showing that this as well as the angular distribution of the emitted radiation can be used to determine the direction of the discharge step. The fine structure of the measured pulse should reflect the time profile of the currents. We are developing an interferometric procedure which will allow us to go beyond single-sample (5 ns) precision to achieve sub-nanosecond timing accuracy. Combined with base-lengths in excess of 50 km this will give us an improvement in resolution by one order of magnitude over existing LMAs. It is of much interest to combine the LOFAR-LIM observations with our recently developed non-invasive method for determining the electric-field in thunderclouds.

An Analysis of Total Lightning Characteristics in Tornadic Storms: Preparing for the Capabilities of the GLM

NASA Astrophysics Data System (ADS)

Reimel, Karly Jackson

Numerous studies have found that severe weather is often preceded by a rapid increase in the total lightning flash rate. This rapid increase results from numerous intra-cloud flashes forming around the periphery of an intensifying updraft. The relationship between flash rates and updraft intensity is extremely useful to forecasters in severe weather warning decision making processes, but total lightning data has not always been widely available. The Geostationary Lightning Mapper (GLM) will be the first instrument to detect lightning from geostationary orbit, where it will provide a continuous view of lightning over the entire western hemisphere. To prepare for the capabilities of this new instrument, this thesis analyzes the relationship between total lightning trends and tornadogenesis. Four supercellular and two non-supercellular tornadic storms are analyzed and compared to determine how total lightning characteristics differ between dynamically different tornadic storms. Supercellular tornadoes require a downdraft to form while landspout tornadoes form within an intensifying updraft acting on pre-existing vertical vorticity. Results of this analysis suggest that the supercellular tornadoes we studied show a decrease in flash rate and a decrease in lightning mapping array (LMA) source density heights prior to the tornado. This decrease may indicate the formation of a downdraft. In contrast, lightning flash rates increase during landspout formation in conjunction with an intensifying updraft. The total lightning trends appear to follow the evolution of an updraft rather than directly responding to tornadogenesis. To further understand how storm microphysics and dynamics impact the relationship between lightning behavior and tornadogenesis, two of the tornadic supercells were analyzed over Colorado and two were analyzed over Alabama. Colorado storms typically exhibit higher flash rates and anomalous charge structures in comparison to the environmentally different Alabama storms that are typically normal polarity and produce fewer flashes. The difference in microphysical characteristics does not appear to affect the relationship between total lightning trends and tornadogenesis. The capabilities of GLM are yet to be determined because the instrument is still in its calibration/validation stages. However, as part of the GLM cal/val team, we were in a unique position to examine the first-light GLM data and contribute to the assessment of its performance for noteworthy thunderstorm events during the Spring/Summer seasons of 2017. The final chapter of this thesis displays a preliminary analysis of GLM data. A first look into GLM performance is established by comparing GLM data with data from other lightning detecting instruments. Overall, GLM appears to detect fewer flashes than other lightning detecting networks and instruments in Colorado storms, more so for intense storms compared to weaker storms.

Location of acoustic radiators and inversion for energy density using radio-frequency sources and thunder recordings

NASA Astrophysics Data System (ADS)

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

2011-12-01

We use radio frequency (VHF) pulse locations mapped with the New Mexico Tech Lightning Mapping Array (LMA) to study the distribution of thunder sources in lightning channels. A least squares inversion is used to fit channel acoustic energy radiation with broadband (0.01 to 500 Hz) acoustic recordings using microphones deployed local (< 10 km) to the lightning. We model the thunder (acoustic) source as a superposition of line segments connecting the LMA VHF pulses. An optimum branching algorithm is used to reconstruct conductive channels delineated by VHF sources, which we discretize as a superposition of finely-spaced (0.25 m) acoustic point sources. We consider total radiated thunder as a weighted superposition of acoustic waves from individual channels, each with a constant current along its length that is presumed to be proportional to acoustic energy density radiated per unit length. Merged channels are considered as a linear sum of current-carrying branches and radiate proportionally greater acoustic energy. Synthetic energy time series for a given microphone location are calculated for each independent channel. We then use a non-negative least squares inversion to solve for channel energy densities to match the energy time series determined from broadband acoustic recordings across a 4-station microphone network. Events analyzed by this method have so far included 300-1000 VHF sources, and correlations as high as 0.5 between synthetic and recorded thunder energy were obtained, despite the presence of wind noise and 10-30 m uncertainty in VHF source locations.

Lightning protection: challenges, solutions and questionable steps in the 21st century

NASA Astrophysics Data System (ADS)

Berta, István

2011-06-01

Besides the special primary lightning protection of extremely high towers, huge office and governmental buildings, large industrial plants and resident parks most of the challenges were connected to the secondary lightning protection of sensitive devices in Information and Communication Technology. The 70 year history of Budapest School of Lightning Protection plays an important role in the research and education of lightning and development of lightning protection. Among results and solutions the Rolling Sphere designing method (RS) and the Probability Modulated Attraction Space (PMAS) theory are detailed. As a new field Preventive Lightning Protection (PLP) has been introduced. The PLP method means the use of special preventive actions only for the duration of the thunderstorm. Recently several non-conventional lightning protection techniques have appeared as competitors of the air termination systems formed of conventional Franklin rods. The questionable steps, non-conventional lightning protection systems reported in the literature are the radioactive lightning rods, Early Streamer Emission (ESE) rods and Dissipation Arrays (sometimes called Charge Transfer Systems).

Advancing research and applications with lightning detection and mapping systems

NASA Astrophysics Data System (ADS)

MacGorman, Donald R.; Goodman, Steven J.

2011-11-01

Southern Thunder 2011 Workshop; Norman, Oklahoma, 11-14 July 2011 The Southern Thunder 2011 (ST11) Workshop was the fourth in a series intended to accelerate research and operational applications made possible by the expanding availability of ground-based and satellite systems that detect and map all types of lightning (in-cloud and cloud-to-ground). This community workshop, first held in 2004, brings together lightning data providers, algorithm developers, and operational users in government, academia, and industry.

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

NASA Technical Reports Server (NTRS)

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.

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

NASA Astrophysics Data System (ADS)

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.

Satellite Proving Ground for the GOES-R Geostationary Lightning Mapper (GLM)

NASA Technical Reports Server (NTRS)

Goodman, Steven J.; Gurka, James; Bruning, E. C.; Blakeslee, J. R.; Rabin, Robert; Buechler, D.

2009-01-01

The key mission of the Satellite Proving Ground is to demonstrate new satellite observing data, products and capabilities in the operational environment to be ready on Day 1 to use the GOES-R suite of measurements. Algorithms, tools, and techniques must be tested, validated, and assessed by end users for their utility before they are finalized and incorporated into forecast operations. The GOES-R Proving Ground for the Geostationary Lightning Mapper (GLM) focuses on evaluating how the infusion of the new technology, algorithms, decision aids, or tailored products integrate with other available tools (weather radar and ground strike networks; nowcasting systems, mesoscale analysis, and numerical weather prediction models) in the hands of the forecaster responsible for issuing forecasts and warning products. Additionally, the testing concept fosters operation and development staff interactions which will improve training materials and support documentation development. Real-time proxy total lightning data from regional VHF lightning mapping arrays (LMA) in Northern Alabama, Central Oklahoma, Cape Canaveral Florida, and the Washington, DC Greater Metropolitan Area are the cornerstone for the GLM Proving Ground. The proxy data will simulate the 8 km Event, Group and Flash data that will be generated by GLM. Tailored products such as total flash density at 1-2 minute intervals will be provided for display in AWIPS-2 to select NWS forecast offices and national centers such as the Storm Prediction Center. Additional temporal / spatial combinations are being investigated in coordination with operational needs and case-study proxy data and prototype visualizations may also be generated from the NASA heritage Lightning Imaging Sensor and Optical Transient Detector data. End users will provide feedback on the utility of products in their operational environment, identify use cases and spatial/temporal scales of interest, and provide feedback to the developers for adjusted or new products.

Where are the lightning hotspots on Earth?

NASA Astrophysics Data System (ADS)

Albrecht, R. I.; Goodman, S. J.; Buechler, D. E.; Blakeslee, R. J.; Christian, H. J., Jr.

2015-12-01

The first lightning observations from space date from the early 1960s and more than a dozen spacecraft orbiting the Earth have flown instruments that recorded lightning signals from thunderstorms over the past 45 years. In this respect, the Tropical Rainfall Measuring Mission (TRMM) Lightning Imaging Sensor (LIS), having just completed its mission (1997-2015), provides the longest and best total (intracloud and cloud-to-ground) lightning data base over the tropics.We present a 16 year (1998-2013) reprocessed data set to create very high resolution (0.1°) TRMM LIS total lightning climatology. This detailed very high resolution climatology is used to identify the Earth's lightning hotspots and other regional features. Earlier studies located the lightning hotspot within the Congo Basin in Africa, but our very high resolution lightning climatology found that the highest lightning flash rate on Earth actually occurs in Venezuela over Lake Maracaibo, with a distinct maximum during the night. The higher resolution dataset clearly shows that similar phenomenon also occurs over other inland lakes with similar conditions, i.e., locally forced convergent flow over a warm lake surface which drives deep nocturnal convection. Although Africa does not have the top lightning hotspot, it comes in a close second and it is the continent with the highest number of lightning hotspots, followed by Asia, South America, North America, and Oceania. We also present climatological maps for local hour and month of lightning maxima, along with a ranking of the highest five hundred lightning maxima, focusing discussion on each continent's 10 highest lightning maxima. Most of the highest continental maxima are located near major mountain ranges, revealing the importance of local topography in thunderstorm development. These results are especially relevant in anticipation of the upcoming availability of continuous total lightning observations from the Geostationary Lightning Mapping (GLM) aboard GOES-R. This study provides context to forecasters as to total lightning activity and locations within GLM field of view as well as around the world.

MSFC shuttle lightning research

NASA Technical Reports Server (NTRS)

Vaughan, Otha H., Jr.

1993-01-01

The shuttle mesoscale lightning experiment (MLE), flown on earlier shuttle flights, and most recently flown on the following space transportation systems (STS's), STS-31, -32, -35, -37, -38, -40, -41, and -48, has continued to focus on obtaining additional quantitative measurements of lightning characteristics and to create a data base for use in demonstrating observation simulations for future spaceborne lightning mapping systems. These flights are also providing design criteria data for the design of a proposed shuttle MLE-type lightning research instrument called mesoscale lightning observational sensors (MELOS), which are currently under development here at MSFC.

Comparisons of GLM and LMA Observations

NASA Astrophysics Data System (ADS)

Thomas, R. J.; Krehbiel, P. R.; Rison, W.; Stanley, M. A.; Attanasio, A.

2017-12-01

Observations from 3-dimensional VHF lightning mapping arrays (LMAs) provide a valuable basis for evaluating the spatial accuracy and detection efficiencies of observations from the recently launched, optical-based Geosynchronous Lightning Mapper (GLM). In this presentation, we describe results of comparing the LMA and GLM observations. First, the observations are compared spatially and temporally at the individual event (pixel) level for sets of individual discharges. For LMA networks in Florida, Colorado, and Oklahoma, the GLM observations are well correlated time-wise with LMA observations but are systematically offset by one- to two pixels ( 10 to 15 or 20 km) in a southwesterly direction from the actual lightning activity. The graphical comparisons show a similar location uncertainty depending on the altitude at which the scattered light is emitted from the parent cloud, due to being observed at slant ranges. Detection efficiencies (DEs) can be accurately determined graphically for intervals where individual flashes in a storm are resolved time-wise, and DEs and false alarm rates can be automated using flash sorting algorithms for overall and/or larger storms. This can be done as a function of flash size and duration, and generally shows high detection rates for larger flashes. Preliminary results during the May 1 2017 ER-2 overflight of Colorado storms indicate decreased detection efficiency if the storm is obscured by an overlying cloud layer.

Fly's Eye GLM Simulator Preliminary Validation Analysis

NASA Astrophysics Data System (ADS)

Quick, M. G.; Christian, H. J., Jr.; Blakeslee, R. J.; Stewart, M. F.; Corredor, D.; Podgorny, S.

2017-12-01

As part of the validation effort for the Geostationary Lightning Mapper (GLM) an airborne radiometer array has been fabricated to observe lightning optical emission through the cloud top. The Fly's Eye GLM Simulator (FEGS) is a multi-spectral, photo-electric radiometer array with a nominal spatial resolution of 2 x 2 km and spatial footprint of 10 x 10 km at cloud top. A main 25 pixel array observes the 777.4 nm oxygen emission triplet using an optical passband filter with a 10 nm FWHM, a sampling rate of 100 kHz, and 16 bit resolution. From March to May of 2017 FEGS was flown on the NASA ER-2 high altitude aircraft during the GOES-R Validation Flight Campaign. Optical signatures of lightning were observed during a variety of thunderstorm scenarios while coincident measurements were obtained by GLM and ground based antennae networks. This presentation will describe the preliminary analysis of the FEGS dataset in the context of GLM validation.

An Overview of the Lightning - Atmospheric Chemistry Aspects of the Deep Convective Clouds and Chemistry (DC3) Experiment

NASA Technical Reports Server (NTRS)

Pickering, K. E.; Barth, M. C.; Koshak, W.; Bucsela, E. J.; Allen, D. J.; Weinheimer, A.; Ryerson, T.; Huntrieser, H.; Bruning, E.; MacGorman, D.;

Assessing Operational Total Lightning Visualization Products

NASA Technical Reports Server (NTRS)

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

2010-01-01

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

The LATEST Project: Operational Assessment of Total Lightning Data in the U.S.

NASA Technical Reports Server (NTRS)

Goodman, Steven

2004-01-01

A government, university, and industry alliance has joined forces to transition total lightning observations from ground-based research networks and NASA satellites (LIS/TRMM) to improve the short range prediction of severe weather. This interest builds on the desire of the U.S Weather Research Program to foster a national Nowcasting Test Bed, with this specific transition activity initiated through the NASA short-term Prediction Research and Transition (SPoRT) Center in Huntsville, AL. A kick-off national workshop sponsored by the SPoRT Center was held in Huntsville April 1-2 to identify the common goals and objectives of the research and operational community, and to assign roles and responsibilities within the alliance. The workshop agenda, presentations, and summary are available at the SPoRT Center Web site ( h h under the "Meetings" tab. The next national workshop is planned for 2005 in Dallas, TX. The NASA North Alabama regional Lightning Mapping Array &MA) has been operational in the Huntsville area for 3 years, and has continuously sampled a variety of severe weather systems during that period. A gridded version of the LMA total lightning data is currently being supplied to National Weather Service offices in Huntsville, Nashville and Birmingham through the NWS AWES decision support system, for the purposes of assessing the utility of the data in the nowcasting of severe weather such as tornadoes, damaging straight line winds, flash flooding and other weather hazards (lightning induced forest fires, microbursts). While the raw LMA data have been useful to NWS forecasters, even greater utility would be realized if higher-order data products could be supplied through AWIPS along with the gridded data over a larger domain. In 2003-2004 additional LMA systems have been deployed across the southern US. from Florida to New Mexico, providing an opportunity for more than 20 NWS forecast offices to evaluate the incremental value of total lightning data in the warning decision making process.

Global optical lightning flash rates determined with the Forte satellite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Light, T.; Davis, S. M.; Boeck, W. L.

2003-01-01

Using FORTE photodiode detector (PDD) observations of lightning, we have determined the geographic distribution of nighttime flash rate density. We estimate the PDD flash detection efficiency to be 62% for total lightning through comparison to lightning observations by the TRMM satellite's Lightning Imaging Sensor (LIS), using cases in which FORTE and TRMM viewed the same storm. We present here both seasonal and l,ot,al flash rate maps. We examine some characteristics of the optical emissions of lightning in both high and low flash rate environments, and find that while lightning occurs less frequently over ocean, oceanic lightning flashes are somewhat moremore » powerful, on average, than those over land.« less

The 1991 International Aerospace and Ground Conference on Lightning and Static Electricity, volume 2

NASA Technical Reports Server (NTRS)

1991-01-01

The proceedings of the conference are reported. The conference focussed on lightning protection, detection, and forecasting. The conference was divided into 26 sessions based on research in lightning, static electricity, modeling, and mapping. These sessions spanned the spectrum from basic science to engineering, concentrating on lightning prediction and detection and on safety for ground facilities, aircraft, and aerospace vehicles.

The 13 years of TRMM Lightning Imaging Sensor: From Individual Flash Characteristics to Decadal Tendencies

NASA Technical Reports Server (NTRS)

Albrecht, R. I.; Goodman, S. J.; Petersen, W. A.; Buechler, D. E.; Bruning, E. C.; Blakeslee, R. J.; Christian, H. J.

2011-01-01

How often lightning strikes the Earth has been the object of interest and research for decades. Several authors estimated different global flash rates using ground-based instruments, but it has been the satellite era that enabled us to monitor lightning thunderstorm activity on the time and place that lightning exactly occurs. Launched into space as a component of NASA s Tropical Rainfall Measuring Mission (TRMM) satellite, in November 1997, the Lighting Imaging Sensor (LIS) is still operating. LIS detects total lightning (i.e., intracloud and cloud-to-ground) from space in a low-earth orbit (35deg orbit). LIS has collected lightning measurements for 13 years (1998-2010) and here we present a fully revised and current total lightning climatology over the tropics. Our analysis includes the individual flash characteristics (number of events and groups, total radiance, area footprint, etc.), composite climatological maps, and trends for the observed total lightning during these 13 years. We have identified differences in the energetics of the flashes and/or the optical scattering properties of the storms cells due to cell-relative variations in microphysics and kinematics (i.e., convective or stratiform rainfall). On the climatological total lightning maps we found a dependency on the scale of analysis (resolution) in identifying the lightning maximums in the tropics. The analysis of total lightning trends observed by LIS from 1998 to 2010 in different temporal (annual and seasonal) and spatial (large and regional) scales, showed no systematic trends in the median to lower-end of the distributions, but most places in the tropics presented a decrease in the highest total lightning flash rates (higher-end of the distributions).

Observations of Two Sprite-Producing Storms in Colorado

NASA Technical Reports Server (NTRS)

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.

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

NASA Astrophysics Data System (ADS)

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

2017-04-01

In the frame of the French atmospheric observatory CORSiCA (http://www.obs-mip.fr/corsica), a total lightning activity detection system called SAETTA (Suivi de l'Activité Electrique Tridimensionnelle Totale de l'Atmosphère) has been deployed in Corsica Island in order to strengthen the potential of observation of convective events causing heavy rainfall and flash floods in the West Mediterranean basin. SAETTA is a network of 12 LMA stations (Lightning Mapping Array) developed by New Mexico Tech (USA). The instrument allows observing lightning flashes in 3D and real time, at high temporal (80 µs) and spatial resolutions. It detects the radiations emitted by cloud discharges in the 60-66 MHz band, in a radius of about 350 km from the centre of the network, in passive mode and standalone (solar panel and batteries). Initially deployed in May 2014, SAETTA operated from July 13 to October 20 in 2014 and from April 19 to December 1st in 2015. It is now in permanent operation since 16 April 2016. Many high quality observations have been performed so far that provide an accurate location in space and time of the convective events. They also bring interesting dynamical and microphysical features of those events. For example the intensity of the convective surges, the transport of charged ice particles in the stratiform area of the thunderclouds can be deduced from SAETTA observations. Specific events have also been detected as well: bolts-from-the-blue, inter cloud discharges, high level discharges in convective but also in stratiform areas, inverted dipoles. The specific lightning patterns of 2015 illustrate the complex influence of the relief, probably via slope and valley winds over Corsica and via induced lee-side convergences over the sea. SAETTA is expected to operate for at least a decade over Corsica so it will participate to the calibration/validation of upcoming lightning detectors from space such as MTG-LI. It will also be a key instrument during the field campaign of the EXAEDRE project during fall 2018 (ANR). Corsica Island becomes now a very interesting area to host field campaigns dedicated to thunderstorm and lightning studies. Acknowledgements: Collectivité Territoriale de Corse through the Fonds Européen de Développement Régional of the European Operational Program 2007-2013 and the Contrat de Plan Etat Région; HyMeX/MISTRALS; Observatoire Midi-Pyrénées; Laboratoire d'Aérologie) and many individuals and regional institutions in Corsica that are hosting the 12 stations of the network or helped us to find sites.

How the Structure of Mesoscale Precipitation Systems Affects their Production of Transient Luminous Events

NASA Astrophysics Data System (ADS)

Lang, T. J.; Lyons, W.; Rutledge, S. A.; Cummer, S. A.; MacGorman, D. R.

2011-12-01

Recently, Lang et al. (2010) analyzed the parent lightning of transient luminous events (TLEs) in the context of the structure and evolution of two mesoscale convective systems (MCSs). These two MCSs were very different - one a giant symmetric leading-line/trailing stratiform storm, and one a small asymmetric MCS that contained a mesoscale convective vortex. These structural differences were associated with substantially different TLE-parent lightning structure as well as TLE production. The results suggested that TLE (especially sprite) production, and TLE-parent positive charge altitude, depend on MCS morphology. Current work is focused on analyzing the structure, evolution, lightning behavior, and TLE production of additional MCSs over various regions of the United States. Several additional TLE-producing MCS cases already have been identified for the years 2008-2010, featuring a variety of organizational modes (symmetric, asymmetric, and other more exotic varieties) in different meteorological regimes (including some cold-season cases). More cases will be incorporated as they occur and are observed. Data sources include geostationary satellite imagery, Doppler radar, three-dimensional lightning mapping networks, ground-strike detection networks, charge moment change measurements, and low-light video observations. The ultimate goal is to further test the hypothesis that MCS structure affects TLE production, and if so to quantify its impact. Research on two Oklahoma case studies, a multicellular system that occurred on 24 March 2009 and a classic bow-echo MCS that occurred on 19 August 2009, is ongoing. Over a 2.5-h period, the March case produced 23 observed TLEs (all sprites) whose parent flashes occurred within 175 km of the Oklahoma Lightning Mapping Array (OKLMA). The median altitude of LMA sources during the TLEs was 5.9 km above Mean Sea Level (MSL), or -19.2 °C. The August storm produced, in 2.5 hours, 34 TLEs (all sprites) with 32 of those having parent flashes within 175 km of the OKLMA. The median altitude for those flashes was higher, 7.1 km MSL, though at a warmer temperature of -14.7 °C due to the time of season. Based on analysis of the radar structures and the lightning data, the two storms support the hypothesized effects of organizational mode on sprite production. In particular, sprite production by the August MCS appeared to benefit from its leading-line/trailing-stratiform structure, which likely led to a higher altitude for the dominant stratiform positive charge layer. This would increase charge moment change, a key metric for the production of sprites.

The start of lightning: Evidence of bidirectional lightning initiation.

PubMed

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

2015-10-16

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

Preparations for Integrating Space-Based Total Lightning Observations into Forecast Operations

NASA Technical Reports Server (NTRS)

Stano, Geoffrey T.; Fuell, Kevin K.; Molthan, Andrew L.

2016-01-01

NASA's Short-term Prediction Research and Transition (SPoRT) Center has been a leader in collaborating with the United States National Weather Service (NWS) offices to integrate ground-based total lightning (intra-cloud and cloud-to-ground) observations into the real-time operational environment. For much of these collaborations, the emphasis has been on training, dissemination of data to the NWS AWIPS system, and focusing on the utility of these data in the warning decision support process. A shift away from this paradigm has occurred more recently for several reasons. For one, SPoRT's collaborations have expanded to new partners, including emergency managers and the aviation community. Additionally, and most importantly, is the impending launch of the GOES-R Geostationary Lightning Mapper (GLM). This has led to collaborative efforts to focus on additional forecast needs, new data displays, develop training for GLM uses based on the lessons learned from ground-based lightning mapping arrays, and ways to better relate total lightning data to other meteorological parameters. This presentation will focus on these efforts to prepare the operational end user community for GLM with an eye towards sharing lessons learned as EUMETSAT prepares for the Meteosat Third Generation Lightning Imager. This will focus on both software and training needs. In particular, SPoRT has worked closely with the Meteorological Development Laboratory to create the total lightning tracking tool. This software allows for NWS forecasters to manually track storms of interest and display a time series trend of observations. This tool also has been expanded to work on any gridded data set allowing for easy visual comparisons of multiple parameters in addition to total lightning. A new web display has been developed for the ground-based observations that can be easily extended to satellite observations. This paves the way for new collaborations outside of the NWS, both domestically and internationally, as the web display will be functional on PCs and mobile devices. Furthermore, SPoRT has helped developed the software plug-in to visualize GLM data. Examples using the official GLM proxy product will be used to provide a glimpse as to what real-time GLM and likely MTG-LI data will be in the near future.

Assessment of the Pseudo Geostationary Lightning Mapper Products at the Spring Program and Summer Experiment

NASA Technical Reports Server (NTRS)

Stano, Geoffrey T.; Calhoun, Kristin K.; Terborg, Amanda M.

2014-01-01

Since 2010, the de facto Geostationary Lightning Mapper (GLM) demonstration product has been the Pseudo-Geostationary Lightning Mapper (PGLM) product suite. Originally prepared for the Hazardous Weather Testbed's Spring Program (specifically the Experimental Warning Program) when only four ground-based lightning mapping arrays were available, the effort now spans collaborations with several institutions and eight collaborative networks. For 2013, NASA's Short-term Prediction Research and Transition (SPoRT) Center and NOAA's National Severe Storms Laboratory have worked to collaborate with each network to obtain data in real-time. This has gone into producing the SPoRT variant of the PGLM that was demonstrated in AWIPS II for the 2013 Spring Program. Alongside the PGLM products, the SPoRT / Meteorological Development Laboratory's total lightning tracking tool also was evaluated to assess not just another visualization of future GLM data but how to best extract more information while in the operational environment. Specifically, this tool addressed the leading request by forecasters during evaluations; provide a time series trend of total lightning in real-time. In addition to the Spring Program, SPoRT is providing the PGLM "mosaic" to the Aviation Weather Center (AWC) and Storm Prediction Center. This is the same as what is used at the Hazardous Weather Testbed, but combines all available networks into one display for use at the national centers. This year, the mosaic was evaluated during the AWC's Summer Experiment. An important distinction between this and the Spring Program is that the Summer Experiment focuses on the national center perspective and not at the local forecast office level. Specifically, the Summer Experiment focuses on aviation needs and concerns and brings together operational forecaster, developers, and FAA representatives. This presentation will focus on the evaluation of SPoRT's pseudo-GLM products in these separate test beds. The emphasis will be on how future GLM observations can support operations at both the local and national scale and how the PGLM was used in combination with other lightning data sets. Evaluations for the PGLM were quite favorable with forecasters appreciating the high temporal resolution, the ability to look for rapid increases in lightning activity ahead of severe weather, as well as situational awareness for where convection is firing and for flight routing.

Lightning in Colorado forest fire smoke plumes during summer 2012

NASA Astrophysics Data System (ADS)

Lang, T. J.; Krehbiel, P. R.; Dolan, B.; Lindsey, D.; Rutledge, S. A.; Rison, W.

2012-12-01

May and June 2012 were unusually hot and dry in Colorado, which was suffering from a strong drought. A major consequence of this climatic regime was one of the most destructive forest fire seasons in state history, with hundreds of thousands of acres of forest and grassland consumed by flames, hundreds of homes burned, and several lives lost. Many of these fires occurred within range of the newly installed Colorado Lightning Mapping Array (COLMA), which provides high-resolution observations of discharges over a large portion of the state. The COLMA was installed in advance of the Deep Convective Clouds and Chemistry (DC3) project. High-altitude lightning was observed to occur sporadically in the smoke plumes over three major fires that occurred during early summer: Hewlett Gulch, High Park, and Waldo Canyon. Additionally, the Colorado State University CHILL (CSU-CHILL) and Pawnee radars observed the Hewlett Gulch plume electrify with detailed polarimetric and dual-Doppler measurements, and also provided these same measurements for the High Park plume when it was not producing lightning. Meanwhile, local Next Generation Radars (NEXRADs) provided observations of the electrified High Park and Waldo Canyon plumes. All of these plumes also were observed by geostationary meteorological satellites. These observations provide an unprecedented dataset with which to study smoke plume and pyrocumulus electrification. The polarimetric data - low reflectivity, high differential reflectivity, low correlation coefficient, and noisy differential phase - were consistent with the smoke plumes and associated pyrocumulus being filled primarily with irregularly shaped ash particles. Lightning was not observed in the plumes until they reached over 10 km above mean sea level, which was an uncommon occurrence requiring explosive fire growth combined with increased meteorological instability and reduced wind shear. Plume updraft intensification and echo-top growth led the occurrence of lightning by 10-15 minutes. Discharges typically only occurred over the span of a few minutes thereafter, or sporadically over the course of one of more hours. Plume lightning was intra-cloud and relatively small in size, and featured extensive precursor activity. Due to the preponderance of ash in the plumes and the lack of precipitation-sized ice, electrification had to occur via some other mechanism besides standard graupel-based non-inductive mechanisms. Triboelectric charging of the ash particles, aided by reduced breakdown fields at high altitudes, is posited as the primary mechanism behind the lightning in these smoke plumes.

The Lightning Mapping Imager (LMI) on the FY-4 satellite and a typical application experiment using the LMI data

NASA Astrophysics Data System (ADS)

Huang, F.; Hui, W.; Li, X.; Liu, R.; Zhang, Z.; Zheng, Y.; Kang, N.

2017-12-01

The Lightning Mapping Imager (LMI) on the FY-4A satellite, which was launched successfully in December 2016, is the first satellite-based lightning detector from space independently developed in China, and one of the world's first two stationary satellite LMIs. The optical imaging technique with a 400x600 CCD array plane and a frequency of 500 frames/s is adopted in the FY-4A LMI to perform real-time and continuous observation of total lightening in the Chinese mainland and adjacent areas. As of July 2017, the in-orbit test shows that the lightening observation date could be accurately obtained by the FY-4A LMI, and that the geo-location could be verified by the ground lightening observation network over China. Since the beginning of the 2017 flood season, every process of strong thunderstorms has been monitored by the FY-4A LMI throughout the various areas of China, and of these are used as a typical application case in this talk. On April 8 and 9, 2017, a strong convective precipitation process occurred in the middle-lower reaches of the Yangtze River, China. The observation data of the FY-4A LMI are used to monitor the occurrence, development, shift and extinction of the thunderstorm track. By means of analyzing the station's synchronous precipitation observation data, it is indicated that the moving track of the thunderstorm is not completely consistent with that of the precipitation center, and while the distribution areas of thunderstorm and precipitation are consistent to a certain extent, a significant difference also exists. This difference is mainly caused by the convective precipitation and stratus precipitation area during the precipitation process. Through comparative analysis, the preliminary satellite and foundation lightening observation data show a higher consistency. However, the time of lightening activity observed by satellite is one hour earlier than that of the ground observation, which is likely related to the total lightning observation by satellite rather than the cloud-ground lightning observation by the ground network. The application test shows that the FY-4A LMI can achieve the real-time and continuous observation on the lightening activity with a strong convective system. This is a significant technological breakthrough in China's lightening detection field.

Thunderstorm distribution and frequency in Saudi Arabia

NASA Astrophysics Data System (ADS)

Shwehdi, M. H.

2005-09-01

A new average annual thunder day map for Saudi Arabia is presented. Based on this map, the distribution of thunderstorms over Saudi Arabia is analysed in terms of the factors related to the lightning performance of transmission lines such as thunderstorm days per year (Td/yr). Lightning activity continues for the present to be represented by thunderstorm frequency, which is routinely recorded at meteorological observation sites. Thunderstorm occurrence at a particular location is usually expressed as the number of days in a calendar year when thunder was heard, averaged over several years. This paper examines thunderstorm days in different areas of Saudi Arabia and specifically those areas where lightning strikes are more frequent; for this purpose, the software ArcGIS is used to produce contour maps which demonstrate areas of concern in Saudi Arabia in the period 1985-2003. Establishing the annual and seasonal Td/yr for Saudi Arabia enables transmission and distribution line engineers to calculate and better design a lightning protection system. Maps of thunder days/year (Td/yr) were constructed on the basis of the database records available on lightning incidence in Saudi Arabia at the Presidency of Meteorology and Environment (PME) (http://www.pme.gov.sa/). Annual thunderstorms are most frequent over the southwestern parts of the country, and generally decrease towards the west and east. Due to its low latitude and less temporal change, the west coast of the Red Sea recorded the lowest Td/yr. A secondary maximum Td/yr is apparent in the southeast to central part of the country. Thunderstorm frequency does not, in general, appear to vary in any consistent way with rainfall. There appears to be no evidence of any widespread temporal trend in thunderstorm frequency. The southern region in general, and especially the cities of Abha, Taif and Al-Baha, has shown greater numbers of thunderstorm days all year round. Similarly, this variation did show higher frequency throughout the year. The development of lightning incidence and the counting of Td/yr, as well as the establishment of annual and seasonal lightning maps of Saudi Arabia, are initiating a new era of producing and archiving thunderstorm maps and data records which serve the PME, the utilities, industry and the public.

Lightning Step Leader and Return Stroke Spectra at 100,000 fps

NASA Astrophysics Data System (ADS)

Harley, J.; McHarg, M.; Stenbaek-Nielsen, H. C.; Haaland, R. K.; Sonnenfeld, R.; Edens, H. E.; Cummer, S.; Lapierre, J. L.; Maddocks, S.

2017-12-01

A fundamental understanding of lightning can be inferred from the spectral emissions resulting from the leader and return stroke channels. We examine events recorded at 00:58:07 on 19 July 2015 and 06:44:24 on 23 July 2017, both at Langmuir Laboratory. Analysis of both events is supplemented by data from the Lightning Mapping Array at Langmuir. The 00:58:07 event spectra was recorded using a 100 line per mm grating in front of a Phantom V2010 camera with an 85mm (9o FOV) Nikon lens recording at 100,000 frames per second. Coarse resolution spectra (approximately 5 nm resolution) are produced from approximately 400 nm to 800 nm for each frame. We analyze several nitrogen and oxygen lines to understand step leader temperature behavior between cloud and ground. The 06:44:24 event spectra was recorded using a 300 line per mm grating (approximately 1.5 nm resolution) in front of a Phantom V2010 camera with an 50mm (32o FOV) Nikon lens also recording at 100,000 frames per second. Two ionized atomic nitrogen lines at 502 nm and 569 nm appear upon attachment and disappear as the return stroke travels from ground to cloud in approximately 5 frames. We analyze these lines to understand initial return stroke temperature and species behavior.

The Statistic Results of the ISUAL Lightning Survey

NASA Astrophysics Data System (ADS)

Chuang, Chia-Wen; Bing-Chih Chen, Alfred; Liu, Tie-Yue; Lin, Shin-Fa; Su, Han-Tzong; Hsu, Rue-Ron

2017-04-01

The ISUAL (Imager for Sprites and Upper Atmospheric Lightning) onboard FORMOSAT-2 is the first science payload dedicated to the study of the lightning-induced transient luminous events (TLEs). Transient events, including TLEs and lightning, were recorded by the intensified imager, spectrophotometer (SP), and array photometer (AP) simultaneously while their light variation observed by SP exceeds a programmed threshold. Therefore, ISUAL surveys not only TLEs but also lightning globally with a good spatial, temporal and spectral resolution. In the past 12 years (2004-2016), approximately 300,000 transient events were registered, and only 42,000 are classified as TLEs. Since the main mission objective is to explore the distribution and characteristics of TLEs, the remaining transient events, mainly lightning, can act as a long-term global lightning survey. These huge amount of events cannot be processed manually as TLEs do, therefore, a data pipeline is developed to scan lightning patterns and to derive their geolocation with an efficient algorithm. The 12-year statistic results including occurrence rate, global distribution, seasonal variation, and the comparison with the LIS/OTD survey are presented in this report.

An Integrated 0-1 Hour First-Flash Lightning Nowcasting, Lightning Amount and Lightning Jump Warning Capability

NASA Technical Reports Server (NTRS)

Mecikalski, John; Jewett, Chris; Carey, Larry; Zavodsky, Brad; Stano, Geoffrey

2015-01-01

Lightning one of the most dangerous weather-related phenomena, especially as many jobs and activities occur outdoors, presenting risk from a lightning strike. Cloud-to-ground (CG) lightning represents a considerable safety threat to people at airfields, marinas, and outdoor facilities-from airfield personnel, to people attending outdoor stadium events, on beaches and golf courses, to mariners, as well as emergency personnel. Holle et al. (2005) show that 90% of lightning deaths occurred outdoors, while 10% occurred indoors despite the perception of safety when inside buildings. Curran et al. (2000) found that nearly half of fatalities due to weather were related to convective weather in the 1992-1994 timeframe, with lightning causing a large component of the fatalities, in addition to tornadoes and flash flooding. Related to the aviation industry, CG lightning represents a considerable hazard to baggage-handlers, aircraft refuelers, food caterers, and emergency personnel, who all become exposed to the risk of being struck within short time periods while convective storm clouds develop. Airport safety protocols require that ramp operations be modified or discontinued when lightning is in the vicinity (typically 16 km), which becomes very costly and disruptive to flight operations. Therefore, much focus has been paid to nowcasting the first-time initiation and extent of lightning, both of CG and of any lightning (e.g, in-cloud, cloud-to-cloud). For this project three lightning nowcasting methodologies will be combined: (1) a GOESbased 0-1 hour lightning initiation (LI) product (Harris et al. 2010; Iskenderian et al. 2012), (2) a High Resolution Rapid Refresh (HRRR) lightning probability and forecasted lightning flash density product, such that a quantitative amount of lightning (QL) can be assigned to a location of expected LI, and (3) an algorithm that relates Pseudo-GLM data (Stano et al. 2012, 2014) to the so-called "lightning jump" (LJ) methodology (Shultz et al. 2011) to monitor lightning trends and to anticipate/forecast severe weather (hail > or =2.5 cm, winds > or =25 m/s, tornadoes). The result will be a time-continuous algorithm that uses GOES satellite, radar fields, and HRRR model fields to nowcast first-flash LI and QL, and subsequently monitors lightning trends on a perstorm basis within the LJ algorithm for possible severe weather occurrence out to > or =3 hours. The LI-QL-LJ product will also help prepare the operational forecast community for Geostationary Lightning Mapper (GLM) data expected in late 2015, as these data are monitored for ongoing convective storms. The LI-QL-LJ product will first predict where new lightning is highly probable using GOES imagery of developing cumulus clouds, followed by n analysis of NWS (dual-polarization) radar indicators (reflectivity at the -10 C altitude) of lightning occurrence, to increase confidence that LI is immanent. Once lightning is observed, time-continuous lightning mapping array and Pseudo-GLM observations will be analyzed to assess trends and the severe weather threat as identified by trends in lightning (i.e. LJs). Additionally, 5- and 15-min GOES imagery will then be evaluated on a per-storm basis for overshooting and other cloud-top features known to be associated with severe storms. For the processing framework, the GOES-R 0-1 hour convective initiation algorithm's output will be developed within the Warning Decision Support System - Integrated Information (WDSS-II) tracking tool, and merged with radar and lightning (LMA/Psuedo-GLM) datasets for active storms. The initial focus of system development will be over North Alabama for select lightning-active days in summer 2014, yet will be formed in an expandable manner. The lightning alert tool will also be developed in concert with National Weather Service (NWS) forecasters to meet their needs for real-time, accurate first-flash LI and timing, as well as anticipated lightning trends, amounts, continuation and cessation, so to provide key situational awareness and decision support information. The NASA Short-term Prediction Research and Transition (SPoRT) Center will provide important logistical and collaborative support and training, involving interactions with the NWS and broader user community.

Investigating lightning-to-ionosphere energy coupling based on VLF lightning propagation characterization

NASA Astrophysics Data System (ADS)

Lay, Erin Hoffmann

In this dissertation, the capabilities of the World-Wide Lightning Location Network (WWLLN) are analyzed in order to study the interactions of lightning energy with the lower ionosphere. WWLLN is the first global ground-based lightning location network and the first lightning detection network that continuously monitors lightning around the world in real time. For this reason, a better characterization of the WWLLN could allow many global atmospheric science problems to be addressed, including further investigation into the global electric circuit and global mapping of regions of the lower ionosphere likely to be impacted by strong lightning and transient luminous events. This dissertation characterizes the World-Wide Location Network (WWLLN) in terms of detection efficiency, location and timing accuracy, and lightning type. This investigation finds excellent timing and location accuracy for WWLLN. It provides the first experimentally-determined estimate of relative global detection efficiency that is used to normalize lightning counts based on location. These normalized global lightning data from the WWLLN are used to map intense storm regions around the world with high time and spatial resolution as well as to provide information on energetic emissions known as elves and terrestrial gamma-ray flashes (TGFs). This dissertation also improves WWLLN by developing a procedure to provide the first estimate of relative lightning stroke radiated energy in the 1-24 kHz frequency range by a global lightning detection network. These characterizations and improvements to WWLLN are motivated by the desire to use WWLLN data to address the problem of lightning-to-ionosphere energy coupling. Therefore, WWLLN stroke rates are used as input to a model, developed by Professor Mengu Cho at the Kyushu Institute of Technology in Japan, that describes the non-linear effect of lightning electromagnetic pulses (EMP) on the ionosphere by accumulating electron density changes resulting from the interaction of the EMP of ten successive lightning strokes with the lower ionosphere. Further studies must be completed to narrow uncertainties in the model, but the qualitative ionospheric response to successive EMPs is presented. Results from this study show that the non-linear effect of lightning EMP due to successive lightning strokes must be taken into account, and varies with altitude, such that the most significant electron density enhancement occurs at 88 km altitude.

Polarimetric radar convective cell tracking reveals large sensitivity of cloud precipitation and electrification properties to CCN

NASA Astrophysics Data System (ADS)

Hu, J.; Rosenfeld, D.; Zhang, P.; Snyder, J.; Orville, R. E.; Ryzhkov, A.; Zrnic, D.; Williams, E. R.; Zhang, R.

2017-12-01

Here we apply the cell tracking methodology, shown in our companion poster, to quantifying factors affecting the vigor and the time-height evolution of hydrometeors and electrification properties of convective cells. Benefitting from the Dual-polarimetric NEXRAD radar network, we composite more than 5000 well-tracked cells among three radars (at Houston, Lubbock and Oklahoma City), stratified by CCN, CAPE and land/sea locations. The analyzed cell properties include Z, ZDR, Kdp, and ρhv, Dm (raindrop diameter) and Nw (raindrop concentration) by the algorithm of Bringi et al. (2003). Lightning Mapping Array (LMA) data is also included in the analysis, which provides a 3D structure of lightning occurrence and RF power. The contrasting CCN conditions over marine, land, pristine and polluted areas are identified based on the satellite retrieval technique described in Rosenfeld et al. (2016). The results show that more CCN are associated with: Increased echo top height, manifesting the invigoration effect. Enhanced reflectivities, especially above the freezing level at around 4.5 km. Raindrop sizes at the initial stage increase at the expense of their concentrations, due to the smaller cloud droplets and suppressed coalescence. Larger propensity for hail. Lightning sources increase with greater CCN concentration and is likely due to the delayed warm rain process and enhanced mixed phase process under more CCN condition, when activated CCN into cloud droplets is too high (> 1000 cm-3) the glaciation is delayed too much and leave little ice at lower levels and thus decrease lightning activity. Land pristine clouds have fewer lightning sources than polluted clouds. Marine pristine clouds seldom have lightning Increased CAPE had a similar effect to the effect of added CCN. The cloud tracking and properties are obtained by a new methodology of Multi-Cell Identification and Tracking (MCIT) algorithm (Hu et al, 2017), with details about the algorithm to be found in the author's accompanying poster session. References [1] Bringi, V. et al., J. Atmos. Sci., 60, 354-365. (2003) [2] Rosenfeld, D. et al., Proc. Natl. Acad. Sci., 113, 5828-5834. (2016) [3] Hu, J. et al., in preparation.

Lightning Magnetic Field Measurements around Langmuir Laboratory

NASA Astrophysics Data System (ADS)

Stock, M.; Krehbiel, P. R.; Rison, W.; Aulich, G. D.; Edens, H. E.; Sonnenfeld, R. G.

2010-12-01

In the absence of artificial conductors, underground lightning transients are produced by diffusion of the horizontal surface magnetic field of a return stroke vertically downward into the conducting earth. The changing magnetic flux produces an orthogonal horizontal electric field, generating a dispersive, lossy transverse electromagnetic wave that penetrates a hundred meters or more into the ground according to the skin depth of the medium. In turn, the electric field produces currents that flow toward or away from the channel to ground depending on the stroke polarity. The underground transients can produce large radial horizontal potential gradients depending on the distance from the discharge and depth below the surface. In this study we focus on the surface excitation field. The goal of the work is to compare measurements of surface magnetic field waveforms B(t) at different distances from natural lightning discharges with simple and detailed models of the return stroke fields. In addition to providing input to the diffusion mechanism, the results should aid in further understanding return stroke field generation processes. The observational data are to be obtained using orthogonal sets of straightened Rogowski coils to measure magnetic field waveforms in N-S and E-W directions. The waveforms are sampled at 500 kS/s over 1.024 second time intervals and recorded directly onto secure digital cards. The instrument operates off of battery power for several days or weeks at a time in remote, unattended locations and measures magnetic field strengths of up to several tens of amperes/meter. The observations are being made in conjunction with collocated slow electric field change measurements and under good 3-D lightning mapping array (LMA) and fast electric field change coverage.

Optical characteristics of lightning and thunderstorm currents

NASA Technical Reports Server (NTRS)

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

1985-01-01

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

The Geostationary Lightning Mapper (GLM) for the GOES-R Series Next Generation Operational Environmental Satellite Constellation

NASA Technical Reports Server (NTRS)

Goodman, Steven J.; Blakeslee, Richard; Koshak, William; Petersen, Walter; Carey, Larry; Mach, Douglas; Buechler, Dennis; Bateman, Monte; McCaul, Eugene; Bruning, Eric;

Development and Observation of the Phase Array Radar at X band

NASA Astrophysics Data System (ADS)

Ushio, T.; Shimamura, S.; Wu, T.; Kikuchi, H.; Yoshida, S.; Kawasaki, Z.; Mizutani, F.; Wada, M.; Satoh, S.; Iguchi, T.

2013-12-01

A new Phased Array Radar (PAR) system for thunderstorm observation has been developed by Toshiba Corporation and Osaka University under a grant of NICT, and installed in Osaka University, Japan last year. It is now well known that rapidly evolving severe weather phenomena (e.g., microbursts, severe thunderstorms, tornadoes) are a threat to our lives particularly in a densely populated area and is closely related to the production of lightning discharges. Over the past decade, mechanically rotating radar systems at the C-band or S-band have been proved to be effective for weather surveillance especially in a wide area more than 100 km in range. However, severe thunderstorm sometimes develops rapidly on the temporal and spatial scales comparable to the resolution limit (-10 min. and -500m) of typical S-band or C-band radar systems, and cannot be fully resolved with these radar systems. In order to understand the fundamental process and dynamics of such fast changing weather phenomena like lightning and tornado producing thunderstorm, volumetric observations with both high temporal and spatial resolution are required. The phased array radar system developed has the unique capability of scanning the whole sky with 100m and 10 to 30 second resolution up to 60 km. The system adopts the digital beam forming technique for elevation scanning and mechanically rotates the array antenna in azimuth direction within 10 to 30 seconds. The radar transmits a broad beam of several degrees with 24 antenna elements and receives the back scattered signal with 128 elements digitizing at each elements. Then by digitally forming the beam in the signal processor, the fast scanning is realized. After the installation of the PAR system in Osaka University, the initial observation campaign was conducted in Osaka urban area with Ku-band Broad Band Radar (BBR) network, C-band weather radar, and lightning location system. The initial comparison with C band radar system shows that the developed PAR system can observe the behavior of the thunderstorm structure in much more detail than any other radar system. The observed high temporal resolution images of the severe thunderstorm and lightning are introduced, showing the potential capabilities of the PAR and lightning location system.

Lightning prevention systems for paper mills

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carpenter, R.B. Jr.

1989-05-01

Paper mills are increasingly relying on sensitive electronic equipment to control their operations. However, the sensitivity of these devices has made mills vulnerable to the effects of lightning strokes. An interruption in the power supply or the destruction of delicate microcircuits can have devastating effects on mill productivity. The authors discuss how lightning strokes can be prevented by a Dissipation Array system (DAS). During the past 17 years, the concept has been applied to a host of applications in regions with a high incidence of lightning activity. With nearly 700 systems now installed, more than 4000 system-years of history havemore » been accumulated. Areas as large as 1 km{sup 2} and towers as high as 2000 ft have been protected and completely isolated from lightning strokes. There have been very few failures, and in every case, the cause of the failure was determined and corrected.« less

Characteristics of VLF/LF Sferics from Elve-producing Lightning Discharges

NASA Astrophysics Data System (ADS)

Blaes, P.; Zoghzoghy, F. G.; Marshall, R. A.

2013-12-01

Lightning return strokes radiate an electromagnetic pulse (EMP) which interacts with the D-region ionosphere; the largest EMPs produce new ionization, heating, and optical emissions known as elves. Elves are at least six times more common than sprites and other transient luminous events. Though the probability that a lightning return stroke will produce an elve is correlated with the return stroke peak current, many large peak current strokes do not produce visible elves. Apart from the lightning peak current, elve production may depend on the return stroke speed, lightning altitude, and ionospheric conditions. In this work we investigate the detailed structure of lightning that gives rise to elves by analyzing the characteristics of VLF/LF lightning sferics in conjunction with optical elve observations. Lightning sferics were observed using an array of six VLF/LF receivers (1 MHz sample-rate) in Oklahoma, and elves were observed using two high-speed photometers pointed over the Oklahoma region: one located at Langmuir Laboratory, NM and the other at McDonald Observatory, TX. Hundreds of elves with coincident LF sferics were observed during the summer months of 2013. We present data comparing the characteristics of elve-producing and non-elve producing lightning as measured by LF sferics. In addition, we compare these sferic and elve observations with FDTD simulations to determine key properties of elve-producing lightning.

A Brief 30-Year Review: Research Highlights from Lightning Mapping Systems 1970-2000

NASA Astrophysics Data System (ADS)

MacGorman, D. R.

2016-12-01

Modern lightning mapping began in the 1970s, the decade in which VHF mapping systems, acoustic mapping systems, and ground strike locating systems were introduced. Adding GPS synchronization of VHF systems in the late 1990s enabled real-time VHF mapping systems to be deployed more extensively. Data these systems provided by 2000 revolutionized our understanding of how storms produce lightning. Among key results: Electrostatics, not electrodynamics, governs where lightning is initiated and where it propagates, contrary to early expectations. Lightning is initiated in a region of large electric field magnitude, typically between a positive charge region and a negative charge region. The geometry of a storm's charge regions governs the spatial extent of each end of the flash. The flash initially propagates bidirectionally toward the two charge regions that initiated it, and once it reaches the charge regions and maximizes the ambient potential difference spanned by the flash structure, it extends through each charge region's ambient electric potential well until the total electric field magnitude at the ends of the flash drops below the threshold for continued propagation. The typical charge distribution producing a cloud-to-ground flash is a region of charge of the polarity being lowered to ground, above a lesser amount of charge of the opposite polarity; the lower region has too little charge to capture the downward propagating channel. Contrary to previous understanding, naturally occurring cloud-to-ground lightning often lowers positive charge to ground, instead of the usual negative charge, in several situations, including winter storms, stratiform precipitation regions, some severe storms, and storms on the High Plains of the United States. The reason cloud-to-ground activity in some storms is dominated by flashes that lower positive charge to ground is that the polarity of the main charge regions in those storms is inverted from the usual polarity, with the main mid-level charge being positive and the main upper-level charge being negative. This strongly implies that the dominant non-inductive electrification mechanism is inverted in those storms, probably because the liquid water content in the mixed phase region is larger than in most storms.

Microphysical and Kinematic Characteristics of Regions of Flash Initiation in a Supercell Storm and a Multicell Storm Observed During the DC3 Field Program

NASA Astrophysics Data System (ADS)

DiGangi, E.; MacGorman, D. R.; Ziegler, C.; Betten, D.; Biggerstaff, M. I.

2017-12-01

Lightning initiation in thunderstorms requires that the local electric field magnitude exceed breakdown values somewhere, and this tends to occur between regions of positive and negative charge, where the largest electric field magnitudes tend to occur. Past studies have demonstrated that, near updrafts, storms with very strong updrafts tend to elevate regions of charge and of flash initiations higher, as well as to have more flashes initiated by small pockets of charge, than in storms with much weaker updrafts. In all thunderstorms, the source of these charge regions is generally thought to be microscopic charge separation via the relative growth rate noninductive mechanism, followed by macroscopic charge separation via sedimentation, although other charge generation mechanisms can contribute to charge in some regions. Charge generation and lightning initiation are therefore inherently dependent on the microphysical and kinematic characteristics of a given storm. This study compares the results of a hydrometeor classification algorithm applied to C-band mobile radar data with mixing ratios calculated by a diabatic Lagrangian analysis retrieval from the dual-Doppler wind fields for two storms, the 29-30 May 2012 supercell storm and the 21 June 2012 multicell storm, observed during the Deep Convective Clouds and Chemistry experiment. Using these data, we then compare the inferred microphysical and kinematic characteristics of regions in which the Oklahoma Lightning Mapping Array indicated that flashes were initiated in these two very different storms.

On polarimetric radar signatures of deep convection for model evaluation: columns of specific differential phase observed during MC3E

DOE Office of Scientific and Technical Information (OSTI.GOV)

van Lier-Walqui, Marcus; Fridlind, Ann; Ackerman, Andrew S

2016-02-01

The representation of deep convection in general circulation models is in part informed by cloud-resolving models (CRMs) that function at higher spatial and temporal resolution; however, recent studies have shown that CRMs often fail at capturing the details of deep convection updrafts. With the goal of providing constraint on CRM simulation of deep convection updrafts, ground-based remote sensing observations are analyzed and statistically correlated for four deep convection events observed during the Midlatitude Continental Convective Clouds Experiment (MC3E). Since positive values of specific differential phase observed above the melting level are associated with deep convection updraft cells, so-called columns aremore » analyzed using two scanning polarimetric radars in Oklahoma: the National Weather Service Vance WSR-88D (KVNX) and the Department of Energy C-band Scanning Atmospheric Radiation Measurement (ARM) Precipitation Radar (C-SAPR). KVNX and C-SAPR volumes and columns are then statistically correlated with vertical winds retrieved via multi-Doppler wind analysis, lightning flash activity derived from the Oklahoma Lightning Mapping Array, and KVNX differential reflectivity . Results indicate strong correlations of volume above the melting level with updraft mass flux, lightning flash activity, and intense rainfall. Analysis of columns reveals signatures of changing updraft properties from one storm event to another as well as during event evolution. Comparison of to shows commonalities in information content of each, as well as potential problems with associated with observational artifacts.« less

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

NASA Technical Reports Server (NTRS)

Winesett, Thomas; Magi, Brian; Cecil, Daniel

2015-01-01

Lightning observations are collected using ground-based and satellite-based sensors. The National Lightning Detection Network (NLDN) in the United States uses multiple ground sensors to triangulate the electromagnetic signals created when lightning strikes the Earth's surface. Satellite-based lightning observations have been made from 1998 to present using the Lightning Imaging Sensor (LIS) on the NASA Tropical Rainfall Measuring Mission (TRMM) satellite, and from 1995 to 2000 using the Optical Transient Detector (OTD) on the Microlab-1 satellite. Both LIS and OTD are staring imagers that detect lightning as momentary changes in an optical scene. Passive microwave remote sensing (85 and 37 GHz brightness temperatures) from the TRMM Microwave Imager (TMI) has also been used to quantify characteristics of thunderstorms related to lightning. Each lightning detection system has fundamental limitations. TRMM satellite coverage is limited to the tropics and subtropics between 38 deg N and 38 deg S, so lightning at the higher latitudes of the northern and southern hemispheres is not observed. The detection efficiency of NLDN sensors exceeds 95%, but the sensors are only located in the USA. Even if data from other ground-based lightning sensors (World Wide Lightning Location Network, the European Cooperation for Lightning Detection, and Canadian Lightning Detection Network) were combined with TRMM and NLDN, there would be enormous spatial gaps in present-day coverage of lightning. In addition, a globally-complete time history of observed lightning activity is currently not available either, with network coverage and detection efficiencies varying through the years. Previous research using the TRMM LIS and Microwave Imager (TMI) showed that there is a statistically significant correlation between lightning flash rates and passive microwave brightness temperatures. The physical basis for this correlation emerges because lightning in a thunderstorm occurs where ice is first present in the cloud and electric charge separation occurs. These ice particles efficiently scatter the microwave radiation at the 85 and 37 GHz frequencies, thus leading to large brightness temperature depressions. Lightning flash rate is related to the total amount of ice passing through the convective updraft regions of thunderstorms. Confirmation of this relationship using TRMM LIS and TMI data, however, remains constrained to TRMM observational limits of the tropics and subtropics. Satellites from the Defense Meteorology Satellite Program (DMSP) have global coverage and are equipped with passive microwave imagers that, like TMI, observe brightness temperatures at 85 and 37 GHz. Unlike the TRMM satellite, however, DMSP satellites do not have a lightning sensor, and the DMSP microwave data has never been used to derive global lightning. In this presentation, a relationship between DMSP Special Sensor Microwave Imager (SSMI) data and ground-based cloud-to-ground (CG) lightning data from NLDN is investigated to derive a spatially complete time history of CG lightning for the USA study area. This relationship is analogous to the established using TRMM LIS and TMI data. NLDN has the most spatially and temporally complete CG lightning data for the USA, and therefore provides the best opportunity to find geospatially coincident observations with SSMI sensors. The strongest thunderstorms generally have minimum 85 GHz Polarized Corrected brightness Temperatures (PCT) less than 150 K. Archived radar data was used to resolve the spatial extent of the individual storms. NLDN data for that storm spatial extent defined by radar data was used to calculate the CG flash rate for the storm. Similar to results using TRMM sensors, a linear model best explained the relationship between storm-specific CG flash rates and minimum 85 GHz PCT. However, the results in this study apply only to CG lightning. To extend the results to weaker storms, the probability of CG lightning (instead of the flash rate) was calculated for storms having 85 GHz PCT greater than 150 K. NLDN data was used to determine if a CG strike occurred for a storm. This probability of CG lightning was plotted as a function of minimum 85 GHz PCT and minimum 37 GHz PCT. These probabilities were used in conjunction with the linear model to estimate the CG flash rate for weaker storms with minimum 85 GHz PCTs greater than 150 K. Results from the investigation of CG lightning and passive microwave radiation signals agree with the previous research investigating total lightning and brightness temperature. Future work will take the established relationships and apply them to the decades of available DMSP data for the USA to derive a map of CG lightning flash rates. Validation of this method and uncertainty analysis will be done by comparing the derived maps of CG lightning flash rates against existing NLDN maps of CG lightning flash rates.

Engineering study of the module/array interface for large terrestrial photovoltaic arrays

NASA Technical Reports Server (NTRS)

1977-01-01

Three major areas--structural, electrical, and maintenance--were evaluated. Efforts in the structural area included establishing acceptance criteria for materials and members, determining loading criteria, and analyzing glass modules in various framing system configurations. Array support structure design was addressed briefly. Electrical considerations included evaluation of module characteristics, intermodule connectors, array wiring, converters and lightning protection. Plant maintenance features such as array cleaning, failure detection, and module installation and replacement were addressed.

Developing the TRYAD Science Instrument

NASA Astrophysics Data System (ADS)

Van Eck, K. T.; Jenke, P.; Briggs, M. S.; Fuchs, J.; Capps, L.

2017-12-01

Terrestrial gamma-ray flashes (TGFs) are brief MeV gamma-ray flashes that are associated with thunderstorms, around 12km in altitude, and are viewed by orbiting satellites. These bright flashes of high energy photons were discovered in 1994. The two major models for TGFs that originate in thunderstorms are the Lightning Leader and Relativistic Feedback Discharge (RFD) model. Both depend on energetic electrons radiating via bremsstrahlung emission. The Lightning Leader model theorizes that lightning step leaders can accelerate electrons to relativistic speeds. The RFD model states that an energetic seed particle can be accelerated to relativistic speeds by strong electric fields inside of a thunderstorm. The main difference in the results of the two models is as follows; the Lightning Leader model results in a wider beam of gamma-rays than the RFD model because the electric field of a thunderstorm is more structured than that of lightning. The TRYAD mission will be the first to fly two detectors, inside CubeSats, in formation to detect TGFs from multiple points in the sky. The data from the CubeSats and the World Wide Lightning Location Network (WWLLN) will likely provide enough insight to constrain or eliminate some of the existing models for TGFs.This summer was spent testing components and constructing the engineering model of the scientific instrument that will be used to detect TGFs. The detector is made up of four lead-doped plastic scintillators which are coupled to arrays of Silicon Photomultipliers (SiPM). The signal from the SiPM array is then fed into a discriminator where a lower energy estimate can be determined and photon counts are recorded. I will present the progress made over the summer constructing the engineering model.

The ENSO Effect on the Temporal and Spatial Distribution of Global Lightning Activity

NASA Technical Reports Server (NTRS)

Chronis, Themis G.; Goodman, Steven J.; Cecil, Dan; Buechler, Dennis; Pittman, Jasna; Robertson, Franklin R.; Blakeslee, Richard J.

2007-01-01

The recently reprocessed (1997-2006) OTD/LIS database is used to investigate the global lightning climatology in response to the ENSO cycle. A linear correlation map between lightning anomalies and ENSO (NINO3.4) identifies areas that generally follow patterns similar to precipitation anomalies. We also observed areas where significant lightning/ENSO correlations are found and are not accompanied of significant precipitation/ENSO correlations. An extreme case of the strong decoupling between lightning and precipitation is observed over the Indonesian peninsula (Sumatra) where positive lightning/NINO3.4 correlations are collocated with negative precipitation/NINO3.4 correlations. Evidence of linear relationships between the spatial extent of thunderstorm distribution and the respective NINO3.4 magnitude are presented for different regions on the Earth. Strong coupling is found over areas remote to the main ENSO axis of influence and both during warm and cold ENSO phases. Most of the resulted relationships agree with the tendencies of precipitation related to ENSO empirical maps or documented teleconnection patterns. Over the Australian continent, opposite behavior in terms of thunderstorm activity is noted for warm ENSO phases with NINO3.4 magnitudes with NINO3.4>+l.08 and 0

Assessing Lightning and Wildfire Hazard by Land Properties and Cloud to Ground Lightning Data with Association Rule Mining in Alberta, Canada

PubMed Central

Cha, DongHwan; Wang, Xin; Kim, Jeong Woo

2017-01-01

Hotspot analysis was implemented to find regions in the province of Alberta (Canada) with high frequency Cloud to Ground (CG) lightning strikes clustered together. Generally, hotspot regions are located in the central, central east, and south central regions of the study region. About 94% of annual lightning occurred during warm months (June to August) and the daily lightning frequency was influenced by the diurnal heating cycle. The association rule mining technique was used to investigate frequent CG lightning patterns, which were verified by similarity measurement to check the patterns’ consistency. The similarity coefficient values indicated that there were high correlations throughout the entire study period. Most wildfires (about 93%) in Alberta occurred in forests, wetland forests, and wetland shrub areas. It was also found that lightning and wildfires occur in two distinct areas: frequent wildfire regions with a high frequency of lightning, and frequent wild-fire regions with a low frequency of lightning. Further, the preference index (PI) revealed locations where the wildfires occurred more frequently than in other class regions. The wildfire hazard area was estimated with the CG lightning hazard map and specific land use types. PMID:29065564

Assessing Lightning and Wildfire Hazard by Land Properties and Cloud to Ground Lightning Data with Association Rule Mining in Alberta, Canada.

PubMed

Cha, DongHwan; Wang, Xin; Kim, Jeong Woo

2017-10-23

Hotspot analysis was implemented to find regions in the province of Alberta (Canada) with high frequency Cloud to Ground (CG) lightning strikes clustered together. Generally, hotspot regions are located in the central, central east, and south central regions of the study region. About 94% of annual lightning occurred during warm months (June to August) and the daily lightning frequency was influenced by the diurnal heating cycle. The association rule mining technique was used to investigate frequent CG lightning patterns, which were verified by similarity measurement to check the patterns' consistency. The similarity coefficient values indicated that there were high correlations throughout the entire study period. Most wildfires (about 93%) in Alberta occurred in forests, wetland forests, and wetland shrub areas. It was also found that lightning and wildfires occur in two distinct areas: frequent wildfire regions with a high frequency of lightning, and frequent wild-fire regions with a low frequency of lightning. Further, the preference index (PI) revealed locations where the wildfires occurred more frequently than in other class regions. The wildfire hazard area was estimated with the CG lightning hazard map and specific land use types.

Preliminary results of the study of lightning location relative to storm structure and dynamics

NASA Technical Reports Server (NTRS)

Rust, W. D.; Taylor, W. L.; Macgorman, D.

1981-01-01

Lightning is being studied relative to storm structure using a VHF space-time discharge mapping system, radar, a cloud-to-ground flash locator, acoustic reconstruction of thunder, and other instrumentation. The horizontal discharge processes within the cloud generally propagate at speeds of 10,000-100,000 m/s. Horizontal extents of lightning were found up to 90 km. In an analysis of a limited number of flashes, lightning occurred in or near regions of high cyclonic shear. Positive cloud-to-ground flashes have been observed emanating from several identifiable regions of severe storms. Lightning echoes observed with 10-cm radar generally are 10-25 dB greater than the largest precipitation echo in the storm.

An Alternative Explanation for "Step-Like" Early VLF Event

NASA Astrophysics Data System (ADS)

Moore, R. C.

2016-12-01

A newly-deployed array of VLF receivers along the East Coast of the United States is ideally suited for detecting VLF scattering from lightning-induced disturbances to the lower ionosphere. The array was deployed in May 2016, and one VLF receiver was deployed only 20 km from the NAA transmitter (24.0 kHz) in Cutler, Maine. The phase of the NAA signal at this closest site varies significantly with time, due simply to the impedance match of the transmitter varying with time. Additionally, both the amplitude and phase exhibit periods of rapid shifts that could possibly explain at least some "step-like" VLF scattering events. Here, we distinguish between "step-like" VLF scattering events and other events in that "step-like" events are typically not closely associated with a detected causative lightning flash and also tend to exhibit little or no recovery to ambient conditions after the event onset. We present an analysis of VLF observations from the East Coast array that demonstrates interesting examples of step-like VLF events far from the transmitter that are associated with step-like events very close to the transmitter. We conclude that step-like VLF events should be treated with caution, unless definitively associated with a causative lightning flash and/or detected using observations of multiple transmitter signals.

Time domain simulations of preliminary breakdown pulses in natural lightning.

PubMed

Carlson, B E; Liang, C; Bitzer, P; Christian, H

2015-06-16

Lightning discharge is a complicated process with relevant physical scales spanning many orders of magnitude. In an effort to understand the electrodynamics of lightning and connect physical properties of the channel to observed behavior, we construct a simulation of charge and current flow on a narrow conducting channel embedded in three-dimensional space with the time domain electric field integral equation, the method of moments, and the thin-wire approximation. The method includes approximate treatment of resistance evolution due to lightning channel heating and the corona sheath of charge surrounding the lightning channel. Focusing our attention on preliminary breakdown in natural lightning by simulating stepwise channel extension with a simplified geometry, our simulation reproduces the broad features observed in data collected with the Huntsville Alabama Marx Meter Array. Some deviations in pulse shape details are evident, suggesting future work focusing on the detailed properties of the stepping mechanism. Preliminary breakdown pulses can be reproduced by simulated channel extension Channel heating and corona sheath formation are crucial to proper pulse shape Extension processes and channel orientation significantly affect observations.

Time domain simulations of preliminary breakdown pulses in natural lightning

PubMed Central

Carlson, B E; Liang, C; Bitzer, P; Christian, H

2015-01-01

Lightning discharge is a complicated process with relevant physical scales spanning many orders of magnitude. In an effort to understand the electrodynamics of lightning and connect physical properties of the channel to observed behavior, we construct a simulation of charge and current flow on a narrow conducting channel embedded in three-dimensional space with the time domain electric field integral equation, the method of moments, and the thin-wire approximation. The method includes approximate treatment of resistance evolution due to lightning channel heating and the corona sheath of charge surrounding the lightning channel. Focusing our attention on preliminary breakdown in natural lightning by simulating stepwise channel extension with a simplified geometry, our simulation reproduces the broad features observed in data collected with the Huntsville Alabama Marx Meter Array. Some deviations in pulse shape details are evident, suggesting future work focusing on the detailed properties of the stepping mechanism. Key Points Preliminary breakdown pulses can be reproduced by simulated channel extension Channel heating and corona sheath formation are crucial to proper pulse shape Extension processes and channel orientation significantly affect observations PMID:26664815

Preliminary study on the Validation of FY-4A Lightning Mapping Imager

NASA Astrophysics Data System (ADS)

Cao, D.; Lu, F.; Qie, X.; Zhang, X.; Huang, F.; Wang, D.

2017-12-01

The FengYun-4 (FY-4) geostationary meteorological satellite is the second generation of China's geostationary meteorological satellite. The FY-4A was launched on December 11th, 2016. It includes a new instrument Lightning Mapping Imager (LMI) for total lightning (cloud and cloud-to-ground flashes) detection. The LMI operates at a wavelength of 777.4nm with 1.9ms integrated time. And it could observe lightning activity continuously day and night with spatial resolution of 7.8 km (sub satellite point) over China region. The product algorithm of LMI consists of false signal filtering and flash clustering analysis. The false signal filtering method is used to identify and remove non-lightning artifacts in optical events. The flash clustering analysis method is used to cluster "event" into "group" and "flash" using specified time and space threshold, and the other non-lightning optical events are filtered further more in the clustering analysis. The ground-based lightning location network (LLN) in China and WWLLN (World Wide Lightning Location Network) were both used to make preliminary validation of LMI. The detection efficiency for cloud-to-ground lightning, spatial and temporal accuracy of LMI were estimated by the comparison of lightning observations from ground-based network and LMI. The day and night biases were also estiamted. Although the LLN and WWLLN mainly observe return strokes in cloud-to-ground flash, the accuracy of LMI still could be estimated for that it was not associated with the flash type mostly. The false alarm efficiency of LMI was estimated using the Geostationary Interferometric Infrared Sounder (GIIRS), another payloads on the FY-4A satellite. The GIIRS could identify the convective cloud region and give more information about the cloud properties. The GIIRS products were used to make a rough evaluation of false alarm efficiency of LMI. The results of this study reveal details of characteristics of LMI instrument. It is also found that the product algorithm of LMI is effective and the LMI products could be used for the analysis of lightning activity in China in a certain extent.

Lightning Forecasts and Data Assimilation into Numerical Weather Prediction Models

NASA Astrophysics Data System (ADS)

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

2012-12-01

This presentation reviews two aspects of lightning in numerical weather prediction (NWP) models: forecasting lightning and assimilating lightning data into NWP models to improve weather forecasts. One of the earliest routine forecasts of lightning was developed for fire weather operations. This approach used a multi-parameter regression analysis of archived cloud-to-ground (CG) lightning data and archived NWP data to optimize the combination of model state variables to use in forecast equations for various CG rates. Since then, understanding of how storms produce lightning has improved greatly. As the treatment of ice in microphysics packages used by NWP models has improved and the horizontal resolution of models has begun approaching convection-permitting scales (with convection-resolving scales on the horizon), it is becoming possible to use this improved understanding in NWP models to predict lightning more directly. An important role for data assimilation in NWP models is to depict the location, timing, and spatial extent of thunderstorms during model spin-up so that the effects of prior convection that can strongly influence future thunderstorm activity, such as updrafts and outflow boundaries, can be included in the initial state of a NWP model run. Radar data have traditionally been used, but systems that map lightning activity with varying degrees of coverage, detail, and detection efficiency are now available routinely over large regions and reveal information about storms that is complementary to the information provided by radar. Because data from lightning mapping systems are compact, easily handled, and reliably indicate the location and timing of thunderstorms, even in regions with little or no radar coverage, several groups have investigated techniques for assimilating these data into NWP models. This application will become even more valuable with the launch of the Geostationary Lightning Mapper on the GOES-R satellite, which will extend routine coverage even farther into remote regions and provides the most promising means for routine thunderstorm detection over oceans. On-going research is continually expanding the methods used to assimilate lightning data, which began with simple techniques for assimilating CG data and now are being extended to assimilate total lightning data. Most approaches either have used the lightning data simply to indicate where the subgrid scale convective parameterization of a model should produce deep convection or have used the lightning data to indicate how to modify a model variable related to thunderstorms, such as rainfall rate or water vapor mixing ratio. The developing methods for explicitly predicting lightning activity provide another, more direct means for assimilating total lightning data, besides providing information valuable to the general public and to many governmental and commercial enterprises. Such a direct approach could be particularly useful for ensemble techniques used to produce probabilistic thunderstorm forecasts.

Infrasound from lightning measured in Ivory Coast

NASA Astrophysics Data System (ADS)

Farges, T.; Matoza, R. S.

2011-12-01

It is well established that more than 2,000 thunderstorms occur continuously around the world and that about 45 lightning flashes are produced per second over the globe. More than two thirds (42) of the infrasound stations of the International Monitoring System (IMS) of the CTBTO (Comprehensive nuclear Test Ban Treaty Organisation) are now certified and routinely measure signals due to natural activity (e.g., airflow over mountains, aurora, microbaroms, surf, volcanoes, severe weather including lightning flashes, ...). Some of the IMS stations are located where worldwide lightning detection networks (e.g. WWLLN) have a weak detection capability but lightning activity is high (e.g. Africa, South America). These infrasound stations are well localised to study lightning flash activity and its disparity, which is a good proxy for global warming. Progress in infrasound array data processing over the past ten years makes such lightning studies possible. For example, Farges and Blanc (2010) show clearly that it is possible to measure lightning infrasound from thunderstorms within a range of distances from the infrasound station. Infrasound from lightning can be detected when the thunderstorm is within about 75 km from the station. The motion of the squall zone is very well measured inside this zone. Up to 25% of lightning flashes can be detected with this technique, giving better results locally than worldwide lightning detection networks. An IMS infrasound station has been installed in Ivory Coast for 8 years. The optical space-based instrument OTD measured a rate of 10-20 flashes/km^2/year in that country and showed strong seasonal variations (Christian et al., 2003). Ivory Coast is therefore a good place to study infrasound data associated with lightning activity and its temporal variation. First statistical results will be presented in this paper based on 3 years of data (2005-2008).

Expanding on the relationship between continuing current and in-cloud leader growth

NASA Astrophysics Data System (ADS)

Lapierre, Jeff L.; Sonnenfeld, Richard G.; Stock, Michael; Krehbiel, Paul R.; Edens, Harald E.; Jensen, Daniel

2017-04-01

When lightning connects to the ground, there is a large surge of current, called the return stroke, which is occasionally followed by a longer-lasting steady current, called continuing current (CC). In a previous study of negative cloud-to-ground (-CG) flashes, we observed the growth rate of in-cloud positive leaders in an attempt to identify occurrences of CC. However, there was no observed change in positive leader growth rate during CC of negative CG flashes. In this study, we use the Langmuir Electric Field Array, Lightning Mapping Array, and Flash-Continuous Broadband Digital Interferometer data to extend the previous study to the growth of the negative leader during positive CG flashes. We have found that in contrast with previous results, negative leader growth during positive CG flashes does show increases in growth rates coincident with CC. Finally, we find that the growth rate magnitudes for positive and negative leaders are typically ˜2-4 km/10 ms and ˜25-40 km/10 ms, respectively. These contrasting results highlight the differences between positive and negative leaders and provide strong evidence as to why -CC and +CC behave differently. Negative leaders inject higher amounts of current and allow the channel to remain conductive throughout the duration of CC. Whereas for positive leaders, the channel becomes nonconductive relatively quickly. It is therefore disconnected from the channel to the ground, and, due to the positive leader's continued growth, an electric potential is built up until a K event is produced that re-ionizes the channel.

Fly's Eye GLM Simulator

NASA Image and Video Library

2017-07-27

The Fly’s Eye GLM Simulator (FEGS) is an airborne array of multi-spectral radiometers optimized to measure the optical emission from lightning. The instrument was designed by the Lightning Group in the Earth Science Office at the Marshall Space Flight Center as part of the validation effort for the first Geostationary Lightning Mapper (GLM) onboard GOES-16. From March to May of 2017, FEGS was flown on the NASA Armstrong Flight Research Center ER-2 along with a payload of other instruments during the GOES-16 Validation Flight Campaign. Data collected during the campaign are being analyzed by scientists at NASA and collaborating institutions to test the accuracy of GLM and other GOES-16 instruments. FEGS adds the capability to investigate sub-millisecond lightning energetics to the NASA Airborne Earth Science program. When flown with its complimentary suite of instruments, the FEGS package observes lightning radiation signatures that span from radio frequencies to gamma-ray emission. Learn more about the GOES-16 Validation Flight Campaign here: https://www.youtube.com/watch?v=rCTIk...

An automatic locating system for cloud-to-ground lightning. [which utilizes a microcomputer

NASA Technical Reports Server (NTRS)

Krider, E. P.; Pifer, A. E.; Uman, M. A.

1980-01-01

Automatic locating systems which respond to cloud to ground lightning and which discriminate against cloud discharges and background noise are described. Subsystems of the locating system, which include the direction finder and the position analyzer, are discussed. The direction finder senses the electromagnetic fields radiated by lightning on two orthogonal magnetic loop antennas and on a flat plate electric antenna. The position analyzer is a preprogrammed microcomputer system which automatically computes, maps, and records lightning locations in real time using data inputs from the direction finder. The use of the locating systems for wildfire management and fire weather forecasting is discussed.

A Ground Flash Fraction Retrieval Algorithm for GLM

NASA Technical Reports Server (NTRS)

Koshak, William J.

2010-01-01

A Bayesian inversion method is introduced for retrieving the fraction of ground flashes in a set of N lightning observed by a satellite lightning imager (such as the Geostationary Lightning Mapper, GLM). An exponential model is applied as a physically reasonable constraint to describe the measured lightning optical parameter distributions. Population statistics (i.e., the mean and variance) are invoked to add additional constraints to the retrieval process. The Maximum A Posteriori (MAP) solution is employed. The approach is tested by performing simulated retrievals, and retrieval error statistics are provided. The approach is feasible for N greater than 2000, and retrieval errors decrease as N is increased.

The Severe Weather Outbreak of 10 November 2002: Lightning and Radar Analysis of Storms in the Deep South

NASA Technical Reports Server (NTRS)

Buechler, D. E.; McCaul, E. W., Jr.; Goodman, S. J.; Blakeslee, R. J.; Bailey, J. C.; Gatlin, P.

2004-01-01

On the afternoon and evening of 10 November 2002, the Midwest and Deep South were struck by a major outbreak of severe storms that produced some 80 tornadoes. In terms of number of tornadoes, this was the largest outbreak in the United States since November 1992. Some 32 of the tornadoes occurred in Tennessee, Mississippi, Alabama and Georgia, including several long-track killers. We use the North Alabama Lightning Mapping Array (LMA) and other data sources to perform a comprehensive analysis of the structure and evolution of the outbreak. Most of the Southern tornadoes occurred in isolated, fast-moving supercell storms that formed in warm, moist air ahead of a major cold front. Storms tended to form in lines parallel to storm cell motion, resulting in many communities being hit multiple times by severe storms that evening. Supercells in Tennessee produced numerous strong tornadoes with short to medium-length track paths, while the supercells further south produced several very long-track tornadoes. Radar data indicate that the Tennessee storms tended to split frequently, apparently limiting their ability to sustain long-lived tornadoes, while storms further south split at most one time. The differences between these storms appear to be related to the presence of stronger jetstream winds in Tennessee relative to those present in Mississippi, Alabama and Georgia. LMA-derived flash rates associated with most of the supercell storm cores were about 1-2 flashes per second. Rapid increases in lightning rates (or "jumps") occurred prior to tornado touchdown in many instances. Lightning "holes" (lightning-free regions associated with the echo-free vault) occurred in two of the Tennessee supercells. The complexity of the relationship between lightning and storm severity is revealed by the behavior of one Alabama supercell, which produced a peak flash rate of nearly 14 flashes per second, well after the end of its long-track tornado, while interacting and ultimately merging with a daughter supercell on its southwest flank. Close examination of this powerful storm indicates that its prodigious flash rate was the result of strong flash activity over an unusually large area, rather than a concentrated core of extremely high flash rate activity.

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

NASA Technical Reports Server (NTRS)

Carcione, Brian C.; Stano, Geoffrey T.

2012-01-01

The 27 April 2011 tornado outbreak brought three distinct waves of tornadic thunderstorms to portions of Mississippi, Alabama, Tennessee, and Georgia, striking the Tennessee Valley of north Alabama and southern Tennessee particularly hard. A total of 42 tornado paths were surveyed across the fourteen county area covered by the National Weather Service (NWS) forecast office in Huntsville, Alabama. Ten of these tornadoes were on the ground for at least 20 miles, two had total path lengths over 130 miles, and six tornadoes were classified as violent (EF-4 or EF-5 on the Enhanced Fujita Scale). Many of these tornadoes occurred within the domain of the North Alabama Lightning Mapping Array (NALMA), a ground-based total lightning detection network owned and operated by the NASA Marshall Space Flight Center. Since 2003, the NASA Short-term Prediction Research and Transition Center has supplied data from NALMA in real time to NWS forecast offices in Huntsville, Knoxville/Tri-Cities, Birmingham, and Nashville. Previous research has documented the utility of total lightning information in predicting tornadogenesis, particularly when combined with other remote sensing tools. Basic warning decision-making during events such as 27 April is not the most difficult part of the process; instead, the focus of warning meteorologists shifts to looking for changes in intensity or possible particularly dangerous situations, since doppler radar velocity data often cannot distinguish between weak and strong tornadoes. To that end, this research attempts to determine if any correlation exists between flash densities of the longest-tracked tornadoes over time, and the surveyed wind speeds of the tornadoes. The long-track EF-5 tornado which struck the Hackleburg, Phil Campbell, and Tanner communities in north Alabama was the primary focus of this research due to its intensity and extended life cycle. However, not all tornadoes were available for total lightning analysis due to widespread power outages which negatively affected the detection efficiency and operation of the NALMA. Therefore, additional storms from 2008-2010 with tracks of at least 20 miles were analyzed for comparison purposes.

The bursts of high energy events observed by the telescope array surface detector

NASA Astrophysics Data System (ADS)

Abbasi, R. U.; Abe, M.; Abu-Zayyad, T.; Allen, M.; Anderson, R.; Azuma, R.; Barcikowski, E.; Belz, J. W.; Bergman, D. R.; Blake, S. A.; Cady, R.; Cheon, B. G.; Chiba, J.; Chikawa, M.; Fujii, T.; Fukushima, M.; Goto, T.; Hanlon, W.; Hayashi, Y.; Hayashida, N.; Hibino, K.; Honda, K.; Ikeda, D.; Inoue, N.; Ishii, T.; Ishimori, R.; Ito, H.; Ivanov, D.; Jui, C. C. H.; Kadota, K.; Kakimoto, F.; Kalashev, O.; Kasahara, K.; Kawai, H.; Kawakami, S.; Kawana, S.; Kawata, K.; Kido, E.; Kim, H. B.; Kim, J. H.; Kim, J. H.; Kishigami, S.; Kitamura, S.; Kitamura, Y.; Kuzmin, V.; Kwon, Y. J.; Lan, J.; Lundquist, J. P.; Machida, K.; Martens, K.; Matsuda, T.; Matsuyama, T.; Matthews, J. N.; Minamino, M.; Mukai, K.; Myers, I.; Nagasawa, K.; Nagataki, S.; Nakamura, T.; Nonaka, T.; Nozato, A.; Ogio, S.; Ogura, J.; Ohnishi, M.; Ohoka, H.; Oki, K.; Okuda, T.; Ono, M.; Onogi, R.; Oshima, A.; Ozawa, S.; Park, I. H.; Pshirkov, M. S.; Rodriguez, D. C.; Rubtsov, G.; Ryu, D.; Sagawa, H.; Saito, K.; Saito, Y.; Sakaki, N.; Sakurai, N.; Sampson, A. L.; Scott, L. M.; Sekino, K.; Shah, P. D.; Shibata, F.; Shibata, T.; Shimodaira, H.; Shin, B. K.; Shin, H. S.; Smith, J. D.; Sokolsky, P.; Springer, R. W.; Stokes, B. T.; Stratton, S. R.; Stroman, T. A.; Suzawa, T.; Takamura, M.; Takeda, M.; Takeishi, R.; Taketa, A.; Takita, M.; Tameda, Y.; Tanaka, H.; Tanaka, K.; Tanaka, M.; Thomas, S. B.; Thomson, G. B.; Tinyakov, P.; Tkachev, I.; Tokuno, H.; Tomida, T.; Troitsky, S.; Tsunesada, Y.; Tsutsumi, K.; Uchihori, Y.; Udo, S.; Urban, F.; Vasiloff, G.; Wong, T.; Yamane, R.; Yamaoka, H.; Yamazaki, K.; Yang, J.; Yashiro, K.; Yoneda, Y.; Yoshida, S.; Yoshii, H.; Zollinger, R.; Zundel, Z.

2017-08-01

The Telescope Array (TA) experiment is designed to detect air showers induced by ultra high energy cosmic rays. The TA ground Surface particle Detector (TASD) observed several short-time bursts of air shower like events. These bursts are not likely due to chance coincidence between single shower events. The expectation of chance coincidence is less than 10-4 for five-year's observation. We checked the correlation between these bursts of events and lightning data, and found evidence for correlations in timing and position. Some features of the burst events are similar to those of a normal cosmic ray air shower, and some are not. On this paper, we report the observed bursts of air shower like events and their correlation with lightning.

Thunderstorm observations by air-shower radio antenna arrays

NASA Astrophysics Data System (ADS)

Apel, W. D.; Arteaga, J. C.; 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.; di Pierro, F.; 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.; Łuczak, 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.

2011-10-01

Relativistic, charged particles present in extensive air showers (EAS) 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 strong electric fields on this detection technique is investigated with the LOPES experiment in Karlsruhe, Germany. The important question if a lightning is initiated by the high electron density given at the maximum of a high-energy cosmic-ray air shower is also investigated, but could not be answered by LOPES. But, these investigations exhibit the capabilities of EAS radio antenna arrays for lightning studies. We report about the studies of LOPES measured radio signals of air showers taken during thunderstorms and give a short outlook to new measurements dedicated to search for correlations of lightning and cosmic rays.

Investigations in thunderstorm energetics using satellite instrumentation and Monte Carlo simulations

NASA Astrophysics Data System (ADS)

Brunner, K. N.; Bitzer, P. M.

2017-12-01

The electrical energy dissipated by lightning is a fundamental question in lightning physics and may be used in severe weather applications. However, the electrical energy, flash area/extent and spectral energy density (radiance) are all influenced by the geometry of the lightning channel. We present details of a Monte Carlo based model simulating the optical emission from lightning and compare with observations. Using time-of-arrival techniques and the electric field change measurements from the Huntsville Alabama Marx Meter Array (HAMMA), the 4D lightning channel is reconstructed. The located sources and lightning channel emit optical emission, calibrated by the ground based electric field, that scatters until absorbed or a cloud boundary is reached within the model. At cloud top, the simulation is gridded as LIS pixels (events) and contiguous events (groups). The radiance is related via the LIS calibration and the estimated lightning electrical energy is calculated at the LIS/GLM time resolution. Previous Monte Carlo simulations have relied on a simplified lightning channel and scattering medium. This work considers the cloud a stratified medium of graupel/ice and inhomogeneous at flash scale. The impact of cloud inhomogeneity on the scattered optical emission at cloud top and at the time resolution of LIS and GLM are also considered. The simulation results and energy metrics provide an estimation of the electrical energy using GLM and LIS on the International Space Station (ISS-LIS).

Using the ENTLN lightning catalog to identify thunder signals in the USArray Transportable Array

NASA Astrophysics Data System (ADS)

Tytell, J. E.; Reyes, J. C.; Vernon, F.; Sloop, C.; Heckman, S.

2013-12-01

Severe weather events can pose a challenge for seismic analysts who regularly see non-seismic signals recorded at the stations. Sometimes, the noise from thunder can be confused with signals from seismic events such as quarry blasts or earthquakes depending on where and when the noise is observed. Automatic analysis of data is also severely affected by big amplitude arrivals that we could safely ignore. A comprehensive lightning catalog for the continental US in conjunction with a travel time model for thunder arrivals can help analysts identify some of these unknown sources. Researchers from Earthscope's USArray Transportable Array (TA) have partnered with the Earth Networks Total Lightning Network (ENTLN) in an effort to create such a catalog. Predicted thunder arrivals from some powerful meteorological systems affecting the main TA footprint will undergo extensive evaluation. We will examine the veracity of the predicted arrivals at different distances and azimuths and the time accuracy of the model. A combination of barometric pressure and seismic signals will be use to verify these arrivals.

Airborne atmospheric electricity experiments

NASA Technical Reports Server (NTRS)

Blakeslee, R. J.

1985-01-01

During the 1984 U2 spring flight program, lightning spectra were measured in the wavelengths from 380 nm to 900 nm with a temporal resolution of 5 ms. With this capability, researchers simultaneously acquired both visible near-infrared lightning spectra on a pulse to pulse basis, so that the spectral variability within a flash, as well as flash to flash variations, can be studied. Preliminary results suggest that important variations do occur, particularly in the strengths of the hydrogen and singly ionized nitrogen emission lines. Also, the results have revealed significant differences in the integrated energy distributions between the lightning spectra measured above clouds and the spectral measurements of cloud-to-ground lightning made at the ground. In particular, the ratio of the energy in the near-IR to that in the visible is around 1 to 2 for cloud top spectra versus about 1/3 for surface observations. Detailed analyses of the 1984 lightning spectral data is being conducted. This data should provide improved understanding about the optical transmission properties of thunderclouds and the physics of the lightning discharge process. Efforts continue on developing and testing background signal removal algorithms using U2 spectometer and optical array sensor day-flight data sets. The goal of this research is to develop an algorithm satisfying Lightning Mapper Sensor requirements.

On polarimetric radar signatures of deep convection for model evaluation: columns of specific differential phase observed during MC3E

PubMed Central

van Lier-Walqui, Marcus; Fridlind, Ann M.; Ackerman, Andrew S.; Collis, Scott; Helmus, Jonathan; MacGorman, Donald R.; North, Kirk; Kollias, Pavlos; Posselt, Derek J.

2017-01-01

The representation of deep convection in general circulation models is in part informed by cloud-resolving models (CRMs) that function at higher spatial and temporal resolution; however, recent studies have shown that CRMs often fail at capturing the details of deep convection updrafts. With the goal of providing constraint on CRM simulation of deep convection updrafts, ground-based remote-sensing observations are analyzed and statistically correlated for four deep convection events observed during the Midlatitude Continental Convective Clouds Experiment (MC3E). Since positive values of specific differential phase (KDP) observed above the melting level are associated with deep convection updraft cells, so-called “KDP columns” are analyzed using two scanning polarimetric radars in Oklahoma: the National Weather Service Vance WSR-88D (KVNX) and the Department of Energy C-band Scanning Atmospheric Radiation Measurement (ARM) Precipitation Radar (C-SAPR). KVNX and C-SAPR KDP volumes and columns are then statistically correlated with vertical winds retrieved via multi-Doppler wind analysis, lightning flash activity derived from the Oklahoma Lightning Mapping Array, and KVNX differential reflectivity (ZDR). Results indicate strong correlations of KDP volume above the melting level with updraft mass flux, lightning flash activity, and intense rainfall. Analysis of KDP columns reveals signatures of changing updraft properties from one storm event to another as well as during event evolution. Comparison of ZDR to KDP shows commonalities in information content of each, as well as potential problems with ZDR associated with observational artifacts. PMID:29503466

On polarimetric radar signatures of deep convection for model evaluation: columns of specific differential phase observed during MC3E.

PubMed

van Lier-Walqui, Marcus; Fridlind, Ann M; Ackerman, Andrew S; Collis, Scott; Helmus, Jonathan; MacGorman, Donald R; North, Kirk; Kollias, Pavlos; Posselt, Derek J

2016-02-01

The representation of deep convection in general circulation models is in part informed by cloud-resolving models (CRMs) that function at higher spatial and temporal resolution; however, recent studies have shown that CRMs often fail at capturing the details of deep convection updrafts. With the goal of providing constraint on CRM simulation of deep convection updrafts, ground-based remote-sensing observations are analyzed and statistically correlated for four deep convection events observed during the Midlatitude Continental Convective Clouds Experiment (MC3E). Since positive values of specific differential phase ( K DP ) observed above the melting level are associated with deep convection updraft cells, so-called " K DP columns" are analyzed using two scanning polarimetric radars in Oklahoma: the National Weather Service Vance WSR-88D (KVNX) and the Department of Energy C-band Scanning Atmospheric Radiation Measurement (ARM) Precipitation Radar (C-SAPR). KVNX and C-SAPR K DP volumes and columns are then statistically correlated with vertical winds retrieved via multi-Doppler wind analysis, lightning flash activity derived from the Oklahoma Lightning Mapping Array, and KVNX differential reflectivity ( Z DR ). Results indicate strong correlations of K DP volume above the melting level with updraft mass flux, lightning flash activity, and intense rainfall. Analysis of K DP columns reveals signatures of changing updraft properties from one storm event to another as well as during event evolution. Comparison of Z DR to K DP shows commonalities in information content of each, as well as potential problems with Z DR associated with observational artifacts.

Peak Source Power Associated with Positive Narrow Bipolar Lightning Pulses

NASA Astrophysics Data System (ADS)

Bandara, S. A.; Marshall, T. C.; Karunarathne, S.; Karunarathne, N. D.; Siedlecki, R. D., II; Stolzenburg, M.

2017-12-01

During the summer of 2016, we deployed a lightning sensor array in and around Oxford Mississippi, USA. The array system comprised seven lightning sensing stations in a network approximately covering an area of 30 km × 30 km. Each station is equipped with four sensors: Fast antenna (10 ms decay time), Slow antenna (1.0 s decay time)), field derivative sensor (dE/dt) and Log-RF antenna (bandwidth 187-192 MHz). We have observed 319 Positive NBPs and herein we report on comparisons of the NBP properties measured from the Fast antenna data with the Log-RF antenna data. These properties include 10-90% rise time, full width at half maximum, zero cross time, and range-normalized amplitude at 100 km. NBPs were categorized according to the fine structure of the electric field wave shapes into Types A-D, as in Karunarathne et al. [2015]. The source powers of NBPs in each category were determined using single station Log-RF data. Furthermore, we also categorized the NBPs in three other groups: initial event of an IC flash, isolated, and not-isolated (according to their spatiotemporal relationship with other lightning activity). We compared the source powers within each category. Karunarathne, S., T. C. Marshall, M. Stolzenburg, and N. Karunarathna (2015), Observations of positive narrow bipolar pulses, J. Geophys. Res. Atmos., 120, doi:10.1002/2015JD023150.

Alabama Ground Operations during the Deep Convective Clouds and Chemistry Experiment

NASA Technical Reports Server (NTRS)

Carey, Lawrence; Blakeslee, Richard; Koshak, William; Bain, Lamont; Rogers, Ryan; Kozlowski, Danielle; Sherrer, Adam; Saari, Matt; Bigelbach, Brandon; Scott, Mariana;

High Speed Intensified Video Observations of TLEs in Support of PhOCAL

NASA Technical Reports Server (NTRS)

Lyons, Walter A.; Nelson, Thomas E.; Cummer, Steven A.; Lang, Timothy; Miller, Steven; Beavis, Nick; Yue, Jia; Samaras, Tim; Warner, Tom A.

2013-01-01

The third observing season of PhOCAL (Physical Origins of Coupling to the upper Atmosphere by Lightning) was conducted over the U.S. High Plains during the late spring and summer of 2013. The goal was to capture using an intensified high-speed camera, a transient luminous event (TLE), especially a sprite, as well as its parent cloud-to-ground (SP+CG) lightning discharge, preferably within the domain of a 3-D lightning mapping array (LMA). The co-capture of sprite and its SP+CG was achieved within useful range of an interferometer operating near Rapid City. Other high-speed sprite video sequences were captured above the West Texas LMA. On several occasions the large mesoscale convective complexes (MCSs) producing the TLE-class lightning were also generating vertically propagating convectively generated gravity waves (CGGWs) at the mesopause which were easily visible using NIR-sensitive color cameras. These were captured concurrent with sprites. These observations were follow-ons to a case on 15 April 2012 in which CGGWs were also imaged by the new Day/Night Band on the Suomi NPP satellite system. The relationship between the CGGW and sprite initiation are being investigated. The past year was notable for a large number of elve+halo+sprite sequences sequences generated by the same parent CG. And on several occasions there appear to be prominent banded modulations of the elves' luminosity imaged at >3000 ips. These stripes appear coincident with the banded CGGW structure, and presumably its density variations. Several elves and a sprite from negative CGs were also noted. New color imaging systems have been tested and found capable of capturing sprites. Two cases of sprites with an aurora as a backdrop were also recorded. High speed imaging was also provided in support of the UPLIGHTS program near Rapid City, SD and the USAFA SPRITES II airborne campaign over the Great Plains.

Systematic investigations of intense convective precipitation events on European scale based on radar- and lightning-cell tracking

NASA Astrophysics Data System (ADS)

Tüchler, Lukas; Meyer, Vera

2013-04-01

The new radar-data and lightning-data based automatic cell identification, tracking and nowcasting tool A-TNT (Austrian Thunderstorm Nowcasting Tool), which has been developed at ZAMG, has been applied to investigate the appearance of thunderstorms at Europe scale. Based on the ec-TRAM-method [1], the algorithm identifies and monitors regions of intense precipitation and lightning activity separately by analyzing sequential two-dimensional intensity maps of radar precipitation rate or lightning densities, respectively. Each data source is processed by a stand-alone identification, tracking and nowcasting procedure. The two tracking results are combined to a "main" cell in a final step. This approach allows that the output derived from the two data sources complement each other giving a more comprehensive picture about the current storm situation. So it is possible to distinguish between pure precipitation cells and thunderstorms, to observe regions, where one data source is not or poorly available, and to compensate for occasional data failures. Consequently, the combined cell-tracks are expected to be more consistent and the cell-tracking more robust. Input data for radar-cell tracking on European Scale is the OPERA radar-composite, which is provided every 15 minutes on a 2 km x 2 km grid, indicating the location and intensity of precipitation over Europe. For the lightning-cell tracking, the lightning-detection data of the EUCLID network is mapped on the OPERA grid. Every five minutes, flash density maps with recorded strokes are created and analyzed. This study will present a detailed investigation of the quality of the identification and tracking results using radar and lightning data. The improvements concerning the robustness and reliability of the cell tracking achieved by combining both data sources will be shown. Analyses about cell tracks and selected storm parameters like frequency, longevity and area will give insight into occurrence, appearance and impact of different severe precipitation events. These studies are performed to support the project HAREN (Hazard Assessment based on Rainfall European Nowcasts, funded by the EC Directorate General for Humanitarian Aid and Civil Protection), which has the objective to improve warnings for hazards induced by precipitation at local scale all over Europe. REFERENCES: [1] Meyer, V. K., H. Höller, and H. D. Betz 2012: Automated thunderstorm tracking and nowcasting: utilization of three-dimensional lightning and radar data. Manuscript accepted for publication in ACPD.

Volcanic Thunder From Explosive Eruptions at Bogoslof Volcano, Alaska

NASA Astrophysics Data System (ADS)

Haney, Matthew M.; Van Eaton, Alexa R.; Lyons, John J.; Kramer, Rebecca L.; Fee, David; Iezzi, Alexandra M.

2018-04-01

Lightning often occurs during ash-producing eruptive activity, and its detection is now being used in volcano monitoring for rapid alerts. We report on infrasonic and sonic recordings of the related, but previously undocumented, phenomenon of volcanic thunder. We observe volcanic thunder during the waning stages of two explosive eruptions at Bogoslof volcano, Alaska, on a microphone array located 60 km away. Thunder signals arrive from a different direction than coeruptive infrasound generated at the vent following an eruption on 10 June 2017, consistent with locations from lightning networks. For the 8 March 2017 eruption, arrival times and amplitudes of high-frequency thunder signals correlate well with the timing and strength of lightning detections. In both cases, the thunder is associated with lightning that continues after significant eruptive activity has ended. Infrasonic and sonic observations of volcanic thunder offer a new avenue for studying electrification processes in volcanic plumes.

Lightning mapping and dual-polarization radar observations of electrified storms at Langmuir Laboratory

NASA Astrophysics Data System (ADS)

Krehbiel, P. R.; Hyland, P. T.; Edens, H. E.; Rison, W.

2013-12-01

Observations being made at Langmuir Laboratory with the NM Tech Lightning Mapping Array (LMA) and the University of Oklahoma ARRC PX-1000 dual polarization X-band radar strongly confirm and expand upon the normal polarity tripolar electrical structure of central New Mexico storms. This is in sharp contrast with the anomalously electrified storm structures observed in northern Colorado during and subsequent to the 2012 DC3 field campaign, as seen with North Colorado LMA and CSU CHILL dual-polarization radar observations. In this presentation we focus on the New Mexico observations, and several modes in which the tripolar structure appears initially to develop and evolve with time. Central New Mexico storms are often prolific producers of negative cloud-to-ground (CG) flashes, but rarely produce positive CGs. By contrast, many or most north Colorado storms are CG-deficient, with the relatively few CG discharges being of predominantly positive polarity. In addition, NM storms commonly produce bolt-from-the-blue (BFB) negative CGs, whereas anomalously electrified Colorado storms produce none. The occurrence of BFBs is indicative of a relatively weak lower positive charge region, while the occurrence of normal downward -CGs is indicative of a somewhat stronger lower positive charge. The lack of -CGs in Colorado storms results from lower positive charge being a dominant storm charge that is elevated in altitude. These and other basic features of the electrically activity of storms, coupled with dual polarization and Doppler radar observations of hydrometeor types and motions, are leading to a better understanding of the storm electrification processes.

ELVES Research at the Pierre Auger Observatory: Optical Emission Simulation and Time Evolution, WWLLN-LIS-Auger Correlations, and Double ELVES Observations and Simulation.

NASA Astrophysics Data System (ADS)

Merenda, K. D.

2016-12-01

Since 2013, the Pierre Auger Cosmic Ray Observatory in Mendoza, Argentina, extended its trigger algorithm to detect emissions of light consistent with the signature from very low frequency perturbations due to electromagnetic pulse sources (ELVES). Correlations with the World Wide Lightning Location Network (WWLLN), the Lightning Imaging Sensor (LIS) and simulated events were used to assess the quality of the reconstructed data. The FD is a pixel array telescope sensitive to the deep UV emissions of ELVES. The detector provides the finest time resolution of 100 nanoseconds ever applied to the study of ELVES. Four eyes, separated by approximately 40 kilometers, consist of six telescopes and span a total of 360 degrees of azimuth angle. The detector operates at night when storms are not in the field of view. An existing 3D EMP Model solves Maxwell's equations using a three dimensional finite-difference time-domain model to describe the propagation of electromagnetic pulses from lightning sources to the ionosphere. The simulation also provides a projection of the resulting ELVES onto the pixel array of the FD. A full reconstruction of simulated events is under development. We introduce the analog signal time evolution comparison between Auger reconstructed data and simulated events on individual FD pixels. In conjunction, we will present a study of the angular distribution of light emission around the vertical and above the causative lightning source. We will also contrast, with Monte Carlo, Auger double ELVES events separated by at most 5 microseconds. These events are too short to be explained by multiple return strokes, ground reflections, or compact intra-cloud lightning sources. Reconstructed ELVES data is 40% correlated to WWLLN data and an analysis with the LIS database is underway.

Applications for predicting precipitation and vegetation patterns at landscape scale using lightning strike data

Treesearch

Deborah Ulinski Potter

1999-01-01

Previous publications discussed the results of my dissertation research on relationships between seasonality in precipitation and vegetation patterns at landscape scale. Summer precipitation at a study site in the Zuni Mountains, NM, was predicted from lightning strike and relative humidity data using multiple regression. Summer precipitation patterns were mapped using...

Characteristics of the Lightning Activities in Southwest China from Low-Earth Orbiting and Geostationary Satellites-, and Ground-based Lightning Observations

NASA Astrophysics Data System (ADS)

Hui, W.; Huang, F.; Guo, Q.; Li, D.; Yao, Z.; Zou, W.

2017-12-01

The development of lightning detection technology accumulates a large amount of long-term data for investigating the lightning activities. Ground-based lightning networks provide continuous lightning location but offer limited spatial coverage because of the complex underlying surface conditions. Space-based optical sensors can detect lightning with global homogeneity. However, observing from satellites in low-earth orbit has fixed locations at the ground very shortly during its overpasses. The latest launched geostationary satellite-based lightning imagers can detect lightning in real time, and provide complete life-cycle coverage of each observed thunderstorm. In this study, based on multi-source lightning data, the lightning activities in southwest China, which with complex terrain and prone to appear lightning, are researched. Firstly, the climatological characteristics of lightning activities in this region from 1998 to 2013 are analyzed by using very-high resolution (0.1°) Lightning Imaging Sensor (LIS)-derived data. The results indicate that the lightning activity is more intense in eastern and southern regions of southwest China than in western and northern regions; the monthly and hourly flash densities also show its obvious seasonal and diurnal variation respectively, which is consistent with the development of the convective systems in the region. The results show that the spatial and temporal distribution of lightning activities in southwest China is related to its topography, water vapor, and atmospheric conditions. Meanwhile, by comparing with the analysis derived data from Chinese Ground-based Lightning Location System, the LIS-based detection results are confirmed. Furthermore, the process of a thunderstorm in southwest China from 29 to 30 March 2017 is investigated by using the new-generation monitoring data of Chinese Fengyun-4 geostationary satellite-based Lightning Mapping Imager (LMI) and the rainfall data. The results tell us more about the behavior of lightning while the thunderstorm traverses through the region, and also demonstrate the correlation between the rainfall amounts and the storm track. This study will contribute to applications of lightning data to improve monitoring and forecasting of severe weather.

A Method for Retrieving Ground Flash Fraction from Satellite Lightning Imager Data

NASA Technical Reports Server (NTRS)

Koshak, William J.

2009-01-01

A general theory for retrieving the fraction of ground flashes in N lightning observed by a satellite-based lightning imager is provided. An "exponential model" is applied as a physically reasonable constraint to describe the measured optical parameter distributions, and population statistics (i.e., mean, variance) are invoked to add additional constraints to the retrieval process. The retrieval itself is expressed in terms of a Bayesian inference, and the Maximum A Posteriori (MAP) solution is obtained. The approach is tested by performing simulated retrievals, and retrieval error statistics are provided. The ability to retrieve ground flash fraction has important benefits to the atmospheric chemistry community. For example, using the method to partition the existing satellite global lightning climatology into separate ground and cloud flash climatologies will improve estimates of lightning nitrogen oxides (NOx) production; this in turn will improve both regional air quality and global chemistry/climate model predictions.

Narrow infrasound pulses from lightning; are they of electrostatic or thermal origin?

NASA Astrophysics Data System (ADS)

CHUM, Jaroslav; Diendorfer, Gerhard; Šindelářová, Tereza; Baše, Jiří; Hruška, František

2014-05-01

Narrow (~1-2 s) infrasound pulses that followed, with ~11 to ~50 s delays, rapid changes of electrostatic field were observed by a microbarometer array in the Czech Republic during thunderstorm activity. The angles of arrival (azimuth and elevation) were analyzed for selected distinct events. Comparisons of distances and azimuths of infrasound sources from the center of microbarometer array with lightning locations determined by EUCLID lightning detection network show that most of the selected events are most likely associated with intra-cloud (IC) discharges. Preceding rapid changes of electrostatic field, potential association of infrasound pulses with IC discharges, and high elevation angles of arrival for near infrasound sources indicate that an electrostatic mechanism is probably responsible for their generation. It is discussed that distinguishing of the relative role of thermal and electrostatic mechanism is difficult, and that none of published models of electrostatic production of infrasound thunder can explain the presented observations precisely. A modification of the current models, based on consideration of at least two charged layers is suggested. Further theoretical and experimental investigations are however needed to get a better description of the generation mechanism of those infrasound pulses.

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

NASA Astrophysics Data System (ADS)

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

2017-02-01

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

Q-Burst Origins in Africa

NASA Astrophysics Data System (ADS)

Boldi, R.; Hobara, Y.; Yamashita, K.; Hayakawa, M.; Satori, G.; Bor, J.; Lyons, W. A.; Nelson, T.; Russell, B.; Williams, E.

2006-12-01

The generation of electromagnetic transient signatures in the SR frequency range (Q-bursts) from the energetic lightning originating in Africa were intensively studied during the AMMA (African Monsoon Multidisciplinary Analysis) field program centered on Niamey, Niger in 2006. During this wet season many active westward- moving MCSs were observed by the MIT C-band Doppler radar. The MCSs exhibited a gust front, a leading squall line and a large spatially-extended (100-200 km) stratiform region that often passed over the observation site. Many transient events were recorded in association with local lightning both with a slow antenna and a DC electric field mill installed near the radar. During the gust front and squall line traverse, the majority of lightning exhibited normal polarity. A remarkable transition of polarity is observed once the radar site is under the stratiform region and a pronounced radar bright band has had time to develop. The majority of the ground flashes then exhibit a positive polarity (positive ground flash). In particular, very intense positive ground flashes (often topped with spider lightning structure) are registered when the radar "hbright band"h is most strongly developed. These positive flashes exhibit a large DC field change in comparison to ones observed during the earlier squall line passage. Video observations of nighttime events support the existence of the lateral extensive spider lightning. Daytime events exhibit thunder durations of a few minutes. ELF Q-bursts were recorded at MIT's Schumann resonance station in Rhode Island U.S.A. (about 8 Mm distance from Niamey) associated with several large well-established positive ground flashes observed locally near Niamey. The event identification is made by accurate GPS timing and arrival direction of the waves. The onset times of the Q-burst are in good agreement with the electric field measurement near Niamey. The arrival directions of the waves are also in good agreement assuming the lightning source near Niamey. Those Q- bursts were generated when the radar observed the bright band in the stratiform region. Africa stands out among the three tropical chimneys in its production of large and energetic positive ground flashes in several independently produced maps of global lightning activity. Comparison of the morphology of convection in radar field programs in Niamey and in Brazil (LBA Program, 1999) have shown far more squall line activity with accompanying stratiform regions in Africa. A large ratio of positive to negative ground flashes in Africa has been documented by the global mapping of Q-bursts, and is consistent with production of positive lightning in the prevalent stratiform regions behind active squall lines. In contrast, a predominance of large negative ground flashes is observed in the Maritime Continent where many lightning sources are located close to (or over) the ocean, and where vigorous continental-style squall lines are relatively scarce. The global maps from Rhode Island U.S. and Moshiri Japan show similar tendency in the distribution of lightning polarity.

MUSIC for localization of thunderstorm cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mosher, J.C.; Lewis, P.S.; Rynne, T.M.

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 surfacemore » 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.« less

Electric Field Sensor for Lightning Early Warning System

NASA Astrophysics Data System (ADS)

Premlet, B.; Mohammed, R.; Sabu, S.; Joby, N. E.

2017-12-01

Electric field mills are used popularly for atmospheric electric field measurements. Atmospheric Electric Field variation is the primary signature for Lightning Early Warning systems. There is a characteristic change in the atmospheric electric field before lightning during a thundercloud formation.A voltage controlled variable capacitance is being proposed as a method for non-contacting measurement of electric fields. A varactor based mini electric field measurement system is developed, to detect any change in the atmospheric electric field and to issue lightning early warning system. Since this is a low-cost device, this can be used for developing countries which are facing adversities. A network of these devices can help in forming a spatial map of electric field variations over a region, and this can be used for more improved atmospheric electricity studies in developing countries.

LEP Events, TLE's, and Q-bursts observed from the Antarctic

NASA Astrophysics Data System (ADS)

Moore, R. C.; Kim, D.; Flint, Q. A.

2017-12-01

ELF/VLF measurements at Palmer Station, McMurdo Station, and South Pole Station, Antarctica are used to detect lightning-generated ELF/VLF radio atmospherics from around the globe and to remote sense ionospheric disturbances in the Southern hemisphere. The Antarctic ELF/VLF receivers complement a Northern hemisphere ELF/VLF monitoring array. In this paper, we present our latest observational results, including a full statistical analysis of conjugate observations of lightning-induced electron precipitation and radio atmospherics associated specifically with the transient luminous events known as gigantic jets and sprites.

A Preliminary ZEUS Lightning Location Error Analysis Using a Modified Retrieval Theory

NASA Technical Reports Server (NTRS)

Elander, Valjean; Koshak, William; Phanord, Dieudonne

2004-01-01

The ZEUS long-range VLF arrival time difference lightning detection network now covers both Europe and Africa, and there are plans for further expansion into the western hemisphere. In order to fully optimize and assess ZEUS lightning location retrieval errors and to determine the best placement of future receivers expected to be added to the network, a software package is being developed jointly between the NASA Marshall Space Flight Center (MSFC) and the University of Nevada Las Vegas (UNLV). The software package, called the ZEUS Error Analysis for Lightning (ZEAL), will be used to obtain global scale lightning location retrieval error maps using both a Monte Carlo approach and chi-squared curvature matrix theory. At the core of ZEAL will be an implementation of an Iterative Oblate (IO) lightning location retrieval method recently developed at MSFC. The IO method will be appropriately modified to account for variable wave propagation speed, and the new retrieval results will be compared with the current ZEUS retrieval algorithm to assess potential improvements. In this preliminary ZEAL work effort, we defined 5000 source locations evenly distributed across the Earth. We then used the existing (as well as potential future ZEUS sites) to simulate arrival time data between source and ZEUS site. A total of 100 sources were considered at each of the 5000 locations, and timing errors were selected from a normal distribution having a mean of 0 seconds and a standard deviation of 20 microseconds. This simulated "noisy" dataset was analyzed using the IO algorithm to estimate source locations. The exact locations were compared with the retrieved locations, and the results are summarized via several color-coded "error maps."

Tropical Cyclone Lightning Distribution and Its Relationship to Convection and Intensity Change

NASA Technical Reports Server (NTRS)

Rodgers, Edward; Wienman, James; Pierce, Harold; Olson, William

2000-01-01

The long distance National Lightning Detection Network (NLDN) was used to monitor the distribution of lightning strokes in various 1998 and 1999 western North Atlantic tropical cyclones. These ground-based lightning observations together with the Defense Meteorological Satellite Program (DMSP) Special Sensor Microwave/Imager (SSM/I) and the Tropical Rain Mapping Mission (TRMM) Microwave Instrument (TMI) derived convective rain rates were used to monitor the propagation of electrically charged convective rain bands aid to qualitatively estimate intensification. An example of the lightning analyses was performed on hurricane George between 25-28 September, 1998 when the system left Key West and moved towards the Louisiana coast. During this period of time, George's maximum winds increased from 38 to 45 meters per second on 25 September and then remained steady state until it made landfall. Time-radius displays of the lightning strokes indicated that the greatest number of lightning strokes occurred within the outer core region (greater than 165 km) with little or no lightning strokes at radii less than 165 km. The trend in these lightning strokes decreased as George move into the Gulf of Mexico and showed no inward propagation. The lack inward propagating lightning strokes with time indicated that there was no evidence that an eye wall replacement was occurring that could alter George's intensity. Since George was steady state at this time, this result is not surprising. Time-azimuth displays of lightning strokes in an annulus whose outer and inner radii were respectively, 222 and 333 km from George's center were also constructed. A result from this analysis indicated that the maximum number of strokes occurred in the forward and rear right quadrant when George was over the Gulf of Mexico. This result is, consistent with the aircraft and satellite observations of maximum rainfall.

A system for mapping sources of VHF and electric field pulses from in-cloud lightning at KSC

NASA Technical Reports Server (NTRS)

Thomson, Ewen M.; Medelius, Pedro J.

1991-01-01

The literature concerning VHF radiation and wideband electric fields from in-cloud lightning is reviewed. VHF location systems give impressive radio images of lightning in clouds with high spatial and temporal resolution. Using systems based on long and short baseline time-or-arrival and interferometry, workers have detected VHF sources that move at speeds of 10(exp 5) to 10(exp 8) m/s. The more slowly moving sources appear to be associated with channel formation but the physical basis for the higher speeds is not clear. In contrast, wideband electric fields are directly related to physical parameters such as current and tortuosity. A long baseline system is described to measure simultaneously VHF radiation and wideband electric fields at five stations at Kennedy Space Center. All signals are detected over remote, isolated ground planes with fiber optics for data transmission. The modification of this system to map rapidly varying dE/dt pulses is discussed.

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

DOE PAGES

Van Eaton, Alexa R.; Behnke, Sonja Ann; Amigo, Alvaro; ...

2016-04-12

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

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

USGS Publications Warehouse

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

2016-01-01

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

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Eaton, Alexa R.; Behnke, Sonja Ann; Amigo, Alvaro

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

Lightning characterization through acoustic and electromagnetic measurements recorded during the HyMeX SOP1 and simulation of the acoustic nonlinear propagation in realistic thunderstorm meteorological conditions

NASA Astrophysics Data System (ADS)

Gallin, L.; Coulouvrat, F.; Farges, T.; Marchiano, R.; Defer, E.; Rison, W.; Schulz, W.; Nuret, M.

2013-12-01

The goal is to study the transformation of the thunder (amplitude, spectrum) during its travel from the lightning channel towards a detector (microphone, microbarometer), considering propagation distances of less than 50 km and complex local meteorological properties. Inside the European HyMeX project, the SOP1 campaign (2012) took place from September 2012 to November 2012 in South of France. An acoustic station (center: 4.39° E, 44.08° N) composed of a microphone array placed inside a microbarometer array was installed by CEA near city of Uzès. It was located in the center of an LMA network coming with two slow antennas. This network was deployed in France for the first time by the New Mexico Tech and LERMA laboratory. The detections from the European lightning location system EUCLID complete this dataset. During the SOP1 period several storms passed over the station. The post-processings of the records point out days with interesting thunderstorms. Especially during the 26th of October 2012 in the evening (around 8 pm) a thunderstorm passed just over the acoustic station. Not too many lightning strokes are detected by EUCLID, the corresponding flashes are then well characterized by the LMA network. Slow antennas present good electric field measurements. The acoustic records have excellent quality. We present for some selected flashes a comparative study of the different measurements (LMA, slow antenna, EUCLID, microphones, microbarometers): focusing on amplitude and spectrum of the thunder waveforms, and on propagation effects due to the meteorological conditions. To quantify the impact of these meteorological conditions on the propagating thunder (from the lightning sources to the acoustic array), a code named Flhoward is used [Dagrau et al., J. Acoust. Soc. Am., 130, 20-32, 2011][Coulouvrat, Wave Motion, 49, 50--63, 2012]. It is designed to simulate the nonlinear propagation of acoustic shock waves through a realistic atmosphere model (including temperature gradients, rigid ground, and wind flows). The meteorological conditions are extracted from the data calculated by Météo-France weather forecast model AROME-WMED for the chosen days. Some cases where numerical simulation helps to understand the observations are presented.

Characteristics of cloud-to-ground lightning flashes along the east coast of the United States

NASA Technical Reports Server (NTRS)

Orville, R. E., Sr.; Pyle, R. B.; Henderson, R. W.; Orville, R. E., Jr.; Weisman, R. A.

1985-01-01

A magnetic direction-finding network for the detection of lightning cloud-to-ground strikes has been installed along the east coast of the United States. Most of the lightning occurring from Maine to Florida and as far west as Ohio is detected. Time, location, flash polarity, stroke count, and peak signal amplitude are recorded in real time. Flash locations, time, and polarity are displayed routinely for research and operational purposes. Flash density maps have been generated for the summers of 1983 and 1984, when the network only extended to North Carolina, and show density maxima in northern Virginia and Maryland.

The effect of the Earth's oblate spheroid shape on the accuracy of a time-of-arrival lightning ground strike locating system

NASA Technical Reports Server (NTRS)

Casper, Paul W.; Bent, Rodney B.

1991-01-01

The algorithm used in previous technology time-of-arrival lightning mapping systems was based on the assumption that the earth is a perfect spheroid. These systems yield highly-accurate lightning locations, which is their major strength. However, extensive analysis of tower strike data has revealed occasionally significant (one to two kilometer) systematic offset errors which are not explained by the usual error sources. It was determined that these systematic errors reduce dramatically (in some cases) when the oblate shape of the earth is taken into account. The oblate spheroid correction algorithm and a case example is presented.

Full-wave reflection of lightning long-wave radio pulses from the ionospheric D region: Comparison with midday observations of broadband lightning signals

NASA Astrophysics Data System (ADS)

Jacobson, Abram R.; Shao, Xuan-Min; Holzworth, Robert

2010-05-01

We are developing and testing a steep-incidence D region sounding method for inferring profile information, principally regarding electron density. The method uses lightning emissions (in the band 5-500 kHz) as the probe signal. The data are interpreted by comparison against a newly developed single-reflection model of the radio wave's encounter with the lower ionosphere. The ultimate application of the method will be to study transient, localized disturbances of the nocturnal D region, including those instigated by lightning itself. Prior to applying the method to study lightning-induced perturbations of the nighttime D region, we have performed a validation test against more stable and predictable daytime observations, where the profile of electron density is largely determined by direct solar X-ray illumination. This article reports on the validation test. Predictions from our recently developed full-wave ionospheric-reflection model are compared to statistical summaries of daytime lightning radiated waveforms, recorded by the Los Alamos Sferic Array. The comparison is used to retrieve best fit parameters for an exponential profile of electron density in the ionospheric D region. The optimum parameter values are compared to those found elsewhere using a narrowband beacon technique, which used totally different measurements, ranges, and modeling approaches from those of the work reported here.

Lightning location relative to storm structure in a supercell storm and a multicell storm

NASA Technical Reports Server (NTRS)

Ray, Peter S.; Macgorman, Donald R.; Rust, W. David; Taylor, William L.; Rasmussen, Lisa Walters

1987-01-01

Relationships between lightning location and storm structure are examined for one radar volume scan in each of two mature, severe storms. One of these storms had characteristics of a supercell storm, and the other was a multicell storm. Data were analyzed from dual-Doppler radar and dual-VHF lightning-mapping systems. The distributions of VHF impulse sources were compared with radar reflectivity, vertical air velocity, and their respective gradients. In the supercell storm, lightning tended to occur along streamlines above and down-shear of the updraft and reflectivity cores; VHF impulse sources were most concentrated in reflectivities between 30 and 40 dBZ and were distributed uniformly with respect to updraft speed. In the multicell storm, on the other hand, lightning tended to coincide with the vertical reflectivity and updraft core and with the diverging streamlines near the top of the storm. The results suggest that the location of lightning in these severe storms were most directly associated with the wind field structure relative to updraft and reflectivity cores. Since the magnitude and vertical shear of the environmental wind are fundamental in determining the reflectivity and wind field structure of a storm, it is suggested that these environmental parameters are also fundamental in determining lightning location.

Spatial products available for identifying areas of likely wildfire ignitions using lightning location data-Wildland Fire Assessment System (WFAS)

Treesearch

Paul Sopko; Larry Bradshaw; Matt Jolly

2016-01-01

The Wildland Fire Assessment System (WFAS, www.wfas.net) is a one-stop-shop giving wildland fire managers the ability to assess fire potential ranging in scale from national to regional and temporally from 1 to 5 days. Each day, broad-area maps are produced from fire weather station and lightning location networks. Three products are created using 24 hour...

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

NASA Astrophysics Data System (ADS)

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

2017-12-01

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

Infrasound pulses from lightning and electrostatic field changes: Observation and discussion

NASA Astrophysics Data System (ADS)

Chum, J.; Diendorfer, G.; Å indelářová, T.; Baše, J.; Hruška, F.

2013-10-01

Narrow (~1-2 s) infrasound pulses that followed, with ~11 to ~50 s delays, rapid changes of electrostatic field were observed by a microbarometer array in the Czech Republic during thunderstorm activity. A positive pressure fluctuation (compression phase) always preceded decompression; the compression was usually higher than the decompression. The angles of arrival (azimuth and elevation) were analyzed for selected distinct events. Comparisons of distances and azimuths of infrasound sources from the center of microbarometer array with lightning locations determined by the European Cooperation for Lighting Detection lightning detection network show that most of the selected events can be very likely associated with intracloud (IC) discharges. The preceding rapid changes of electrostatic field, their potential association with IC discharges, and high-elevation angles of arrival for near infrasound sources indicate that an electrostatic mechanism is probably responsible for their generation. It is discussed that distinguishing the relative role of thermal and electrostatic mechanism is difficult and that none of the published models of electrostatic production of infrasound thunder can explain the presented observations precisely. A modification of the current models, based on consideration of at least two charged layers, is suggested. Further theoretical and experimental investigations are however needed to get a better description of the generation mechanism.

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

NASA Astrophysics Data System (ADS)

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

2018-05-01

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

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

NASA Astrophysics Data System (ADS)

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

2015-04-01

Located in the West Mediterranean basin, Corsica is strategically positioned for atmospheric studies referred by MISTRALS/HyMeX and MISTRALS/CHARMEX programs. The implementation of the project of atmospheric observatory CORSiCA (supported by the Collectivité Territoriale de Corse via CPER/FEDER funds) was an opportunity to strengthen the potential observation of convective events causing heavy rainfall and flash floods, by acquiring a total lightning activity detection system adapted to storm tracking at a regional scale. This detection system called SAETTA (Suivi de l'Activité Electrique Tridimensionnelle Totale de l'Atmosphère) is a network of 12 LMA stations (Lightning Mapping Array). Developed by New Mexico Tech (USA), the instrument allows observing lightning flashes in 3D and real time, at high temporal and spatial resolutions. It detects the radiations emitted by cloud discharges in the 60-66 MHz band, in a radius of about 300 km from the centre of the network, in passive mode and standalone (solar panel and battery). Each LMA station samples the signal at high rate (80 microseconds), records data on internal hard disk, and transmits a decimated signal in real-time via the 3G phone network. The decimated data are received on a server that calculates the position of the detected sources by the time-of-arrival method and manages a quasi real-time display on a website. The non decimated data intended for research applications are recovered later on the field. Deployed in May and June 2014, SAETTA operated nominally from July 13 to October 20, 2014. It is to be definitively re-installed in spring 2015 after a hardware updating. The operation of SAETTA is contractually scheduled until the end of 2019, but it is planned to continue well beyond to obtain longer-term observations for addressing issues related to climatic trends. SAETTA has great scientific potential in a broad range of topics: physics of discharge; monitoring and simulation of storm systems; climatology of convection in the western Mediterranean; production of nitrogen oxides by lightning; influence of pollution and aerosols on the electrical activity; synergy with operational lightning networks (EUCLID, ATDnet, Linet, ZEUS) and radar observations (ARAMIS). SAETTA should also become a validation tool for space observation of lightning (e.g. TARANIS mission and optical flash sensor on Meteosat Third Generation), but also for field campaigns. Acknowledgements are adressed to CORSiCA-SAETTA main sponsors (Collectivité Territoriale de Corse through the Fonds Européen de Développement Régional of the European Operational Program 2007-2013 and the Contrat de Plan Etat Région; HyMeX/MISTRALS; Observatoire Midi-Pyrénées; Laboratoire d'Aérologie) and many individuals and regional institutions in Corsica that host the 12 stations of the network or that helped us to find sites.

Storm Physics and Lightning Properties over Northern Alabama during DC3

NASA Astrophysics Data System (ADS)

Matthee, R.; Carey, L. D.; Bain, A. L.

2013-12-01

The Deep Convective Clouds and Chemistry (DC3) experiment seeks to examine the relationship between deep moist convection (DMC) and the production of nitrogen oxides (NOx) via lightning (LNOx). The focus of this study will be to examine integrated storm microphysics and lightning properties of DMC across northern Alabama (NA) during the DC3 campaign through use of polarimetric radar [UAHuntsville's Advanced Radar for Meteorological and Operational Radar (ARMOR)] and lightning mapping [National Aeronautical and Space Administration's (NASA) north Alabama Lightning Mapping Array (NA LMA)] platforms. Specifically, ARMOR and NA LMA are being used to explore the ability of radar inferred microphysical (e.g., ice mass, graupel volume) measurements to parameterize flash rates (F) and flash area for estimation of LNOX production in cloud resolving models. The flash area was calculated by using the 'convex hull' method. This method essentially draws a polygon around all the sources that comprise a flash. From this polygon, the convex hull area that describes the minimum polygon that circumscribes the flash extent is calculated. Two storms have been analyzed so far; one on 21 May 2012 (S1) and another on 11 June 2012 (S2), both of which were aircraft-penetrated during DC3. For S1 and S2, radar reflectivity (Z) estimates of precipitation ice mass (M) within the mixed-phase zone (-10°C to -40°C) were well correlated to the trend of lightning flash rate. However, a useful radar-based F parameterization must provide accurate quantification of rates in addition to proper trends. The difference reflectivity was used to estimate Z associated with ice and then a single Z-M relation was employed to calculate M in the mixed-phase zone. Using this approach it was estimated that S1 produced an order of magnitude greater M, but produced about a third of the total amount of flashes compared to S2. Expectations based on the non-inductive charging (NIC) theory suggest that the M-to-F ratio (M/F) should be stable from storm-to-storm, amongst other factors, all else being equal. Further investigation revealed that the mean mixed-phase Z was 11 dB higher in S1 compared to S2, suggesting larger diameters and lower concentrations of ice particles in S1. Reduction by an order of magnitude of the intercept parameter (N0) of an assumed exponential ice particle size distribution within the Z-M relation for S1 resulted in a proportional reduction in S1's inferred M and therefore a more comparable M/F ratio between the storms. Flash statistics between S1 and S2 revealed the following: S1 produced 1.92 flashes/minute and a total of 102 flashes, while S2 produced 3.45 flashes/minute and a total of 307 flashes. On average, S1 (S2) produced 212 (78) sources per flash and an average flash area of 89.53 km2 (53.85 km2). Thus, S1 produced fewer flashes, a lower F, but more sources per flash and larger flash areas as compared to S2. Ongoing analysis is exploring the tuning of N0 within the Z-M relation by the mean Z in the mixed-phase zone. The suitability of various M estimates and other radar properties (graupel volume, ice fluxes, anvil ice mass) for parameterizing F, flash area and LNOX will be investigated on different storm types across NA.

Modeling of X-ray Images and Energy Spectra Produced by Stepping Lightning Leaders

NASA Astrophysics Data System (ADS)

Xu, Wei; Marshall, Robert A.; Celestin, Sebastien; Pasko, Victor P.

2017-11-01

Recent ground-based measurements at the International Center for Lightning Research and Testing (ICLRT) have greatly improved our knowledge of the energetics, fluence, and evolution of X-ray emissions during natural cloud-to-ground (CG) and rocket-triggered lightning flashes. In this paper, using Monte Carlo simulations and the response matrix of unshielded detectors in the Thunderstorm Energetic Radiation Array (TERA), we calculate the energy spectra of X-rays as would be detected by TERA and directly compare with the observational data during event MSE 10-01. The good agreement obtained between TERA measurements and theoretical calculations supports the mechanism of X-ray production by thermal runaway electrons during the negative corona flash stage of stepping lightning leaders. Modeling results also suggest that measurements of X-ray bursts can be used to estimate the approximate range of potential drop of lightning leaders. Moreover, the X-ray images produced during the leader stepping process in natural negative CG discharges, including both the evolution and morphological features, are theoretically quantified. We show that the compact emission pattern as recently observed in X-ray images is likely produced by X-rays originating from the source region, and the diffuse emission pattern can be explained by the Compton scattering effects.

Augmenting Satellite Precipitation Estimation with Lightning Information

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mahrooghy, Majid; Anantharaj, Valentine G; Younan, Nicolas H.

2013-01-01

We have used lightning information to augment the Precipitation Estimation from Remotely Sensed Imagery using an Artificial Neural Network - Cloud Classification System (PERSIANN-CCS). Co-located lightning data are used to segregate cloud patches, segmented from GOES-12 infrared data, into either electrified (EL) or non-electrified (NEL) patches. A set of features is extracted separately for the EL and NEL cloud patches. The features for the EL cloud patches include new features based on the lightning information. The cloud patches are classified and clustered using self-organizing maps (SOM). Then brightness temperature and rain rate (T-R) relationships are derived for the different clusters.more » Rain rates are estimated for the cloud patches based on their representative T-R relationship. The Equitable Threat Score (ETS) for daily precipitation estimates is improved by almost 12% for the winter season. In the summer, no significant improvements in ETS are noted.« less

Application of Artificial Thunderstorm Cells for the Investigation of Lightning Initiation Problems between a Thundercloud and the Ground

NASA Astrophysics Data System (ADS)

Temnikov, A. G.; Chernensky, L. L.; Orlov, A. V.; Lysov, N. Y.; Zhuravkova, D. S.; Belova, O. S.; Gerastenok, T. K.

2017-12-01

The results of the experimental application of artificial thunderstorm cells of negative and positive polarities for the investigation of the lightning initiation problems between the thundercloud and the ground using model hydrometeor arrays are presented. Possible options of the initiation and development of a discharge between the charged cloud and the ground in the presence of model hydrometeors are established. It is experimentally shown that groups of large hydrometeors of various shapes significantly increase the probability of channel discharge initiation between the artificial thunderstorm cell and the ground, especially in the case of positive polarity of the cloud. The authors assume that large hail arrays in the thundercloud can initiate the preliminary breakdown stage in the lower part of the thundercloud or initiate and stimulate the propagation of positive lightning from its upper part. A significant effect of the shape of model hydrometeors and the way they are grouped on the processes of initiation and stimulation of the channel discharge propagation in the artificial thunderstorm cell of negative or positive polarity-ground gap is experimentally established. It is found that, in the case of negative polarity of a charged cloud, the group of conductive cylindrical hydrometeors connected by a dielectric string more effectively initiates the channel discharge between the artificial thunderstorm cell and the ground. In the case of positive polarity of the artificial thunderstorm cell, the best effect of the channel discharge initiation is achieved for model hydrometeors grouped together by the dielectric tape. The obtained results can be used in the development of the method for the directed artificial lightning initiation between the thundercloud and the ground.

Effects of a Longer Detection Window in VHF Time-of-Arrival Lightning Detection Systems

NASA Astrophysics Data System (ADS)

Murphy, M.; Holle, R.; Demetriades, N.

2003-12-01

Lightning detection systems that operate by measuring the times of arrival (TOA) of short bursts of radiation at VHF can produce huge volumes of data. The first automated system of this kind, the NASA Kennedy Space Center LDAR network, is capable of producing one detection every 100 usec from each of seven sensors (Lennon and Maier, 1991), where each detection consists of the time and amplitude of the highest-amplitude peak observed within the 100 usec window. More modern systems have been shown to produce very detailed information with one detection every 10 usec (Rison et al., 2001). Operating such systems in real time, however, can become expensive because of the large data communications rates required. One solution to this problem is to use a longer detection window, say 500 usec. In principle, this has little or no effect on the flash detection efficiency because each flash typically produces a very large number of these VHF bursts (known as sources). By simply taking the largest-amplitude peak from every 500-usec interval instead of every 100-usec interval, we should detect the largest 20{%} of the sources that would have been detected using the 100-usec window. However, questions remain about the exact effect of a longer detection window on the source detection efficiency with distance from the network, its effects on how well flashes are represented in space, and how well the reduced information represents the parent thunderstorm. The latter issue is relevant for automated location and tracking of thunderstorm cells using data from VHF TOA lightning detection networks, as well as for understanding relationships between lightning and severe weather. References Lennon, C.L. and L.M. Maier, Lightning mapping system. Proceedings, Intl. Aerospace and Ground Conf. on Lightning and Static Elec., Cocoa Beach, Fla., NASA Conf. Pub. 3106, vol. II, pp. 89-1 - 89-10, 1991. Rison, W., P. Krehbiel, R. Thomas, T. Hamlin, J. Harlin, High time resolution lightning mapping observations of a small thunderstorm during STEPS. Eos Trans. AGU, 82 (47), Fall Meet. Suppl., Abstract AE12A-83, 2001.

Phased Array Radar Network Experiment for Severe Weather

NASA Astrophysics Data System (ADS)

Ushio, T.; Kikuchi, H.; Mega, T.; Yoshikawa, E.; Mizutani, F.; Takahashi, N.

2017-12-01

Phased Array Weather Radar (PAWR) was firstly developed in 2012 by Osaka University and Toshiba under a grant of NICT using the Digital Beamforming Technique, and showed a impressive thunderstorm behavior with 30 second resolution. After that development, second PAWR was installed in Kobe city about 60 km away from the first PAWR site, and Tokyo Metropolitan University, Osaka Univeristy, Toshiba and the Osaka Local Government started a new project to develop the Osaka Urban Demonstration Network. The main sensor of the Osaka Network is a 2-node Phased Array Radar Network and lightning location system. Data products that are created both in local high performance computer and Toshiba Computer Cloud, include single and multi-radar data, vector wind, quantitative precipitation estimation, VIL, nowcasting, lightning location and analysis. Each radar node is calibarated by the baloon measurement and through the comparison with the GPM (Global Precipitation Measurement)/ DPR (Dual Frequency Space borne Radar) within 1 dB. The attenuated radar reflectivities obtained by the Phased Array Radar Network at X band are corrected based on the bayesian scheme proposed in Shimamura et al. [2016]. The obtained high resolution (every 30 seconds/ 100 elevation angles) 3D reflectivity and rain rate fields are used to nowcast the surface rain rate up to 30 minutes ahead. These new products are transferred to Osaka Local Government in operational mode and evaluated by several section in Osaka Prefecture. Furthermore, a new Phased Array Radar with polarimetric function has been developed in 2017, and will be operated in the fiscal year of 2017. In this presentation, Phased Array Radar, network architecuture, processing algorithm, evalution of the social experiment and first Multi-Prameter Phased Array Radar experiment are presented.

The Geostationary Lighting Mapper (GLM) for GOES-R: A New Operational Capability to Improve Storm Forecasts and Warnings

NASA Technical Reports Server (NTRS)

Goodman, Steven J.; Blakeslee, R.; Koshak, William J.; Petersen, W. A.; Carey, L.; Mah, D.

2010-01-01

The next generation Geostationary Operational Environmental Satellite (GOES-R) series is a follow on to the existing GOES system currently operating over the Western Hemisphere. Superior spacecraft and instrument technology will support expanded detection of environmental phenomena, resulting in more timely and accurate forecasts and warnings. Advancements over current GOES capabilities include a new capability for total lightning detection (cloud and cloud-to-ground flashes) from the Geostationary Lightning Mapper (GLM), and improved spectral (3x), spatial (4x), and temporal (5x) resolution for the Advanced Baseline Imager (ABI). The GLM, an optical transient detector and imager operating in the near-IR at 777.4 nm will map all (in-cloud and cloud-to-ground) lighting flashes continuously day and night with near-uniform spatial resolution of 8 km with a product refresh rate of less than 20 sec over the Americas and adjacent oceanic regions, from the west coast of Africa (GOES-E) to New Zealand (GOES-W) when the constellation is fully operational. This will aid in forecasting severe storms and tornado activity, and convective weather impacts on aviation safety and efficiency. In parallel with the instrument development (a prototype and 4 flight models), a GOES-R Risk Reduction Team and Algorithm Working Group Lightning Applications Team have begun to develop the Level 2 algorithms and applications. Proxy total lightning data from the NASA Lightning Imaging Sensor on the Tropical Rainfall Measuring Mission (TRMM) satellite and regional test beds are being used to develop the pre-launch algorithms and applications, and also improve our knowledge of thunderstorm initiation and evolution. Real time lightning mapping data are being provided in an experimental mode to selected National Weather Service (NWS) national centers and forecast offices via the GOES-R Proving Ground to help improve our understanding of the application of these data in operational settings and facilitate Day-1 user readiness for this new capability.

Infra-sound Signature of Lightning

NASA Astrophysics Data System (ADS)

Arechiga, R. O.; Badillo, E.; Johnson, J.; Edens, H. E.; Rison, W.; Thomas, R. J.

2012-12-01

We have analyzed thunder from over 200 lightning flashes to determine which part of thunder comes from the gas dynamic expansion of portions of the rapidly heated lightning channel and which from electrostatic field changes. Thunder signals were recorded by a ~1500 m network of 3 to 4 4-element microphone deployed in the Magdalena mountains of New Mexico in the summers of 2011 and 2012. The higher frequency infra-sound and audio-range portion of thunder is thought to come from the gas dynamic expansion, and the electrostatic mechanism gives rise to a signature infra-sound pulse peaked at a few Hz. More than 50 signature infra-sound pulses were observed in different portions of the thunder signal, with no preference towards the beginning or the end of the signal. Detection of the signature pulse occurs sometimes only for one array and sometimes for several arrays, which agrees with the theory that the pulse is highly directional (i.e., the recordings have to be in a specific position with respect to the cloud generating the pulse to be able to detect it). The detection of these pulses under quiet wind conditions by different acoustic arrays corroborates the electrostatic mechanism originally proposed by Wilson [1920], further studied by Dessler [1973] and Few [1985], observed by Bohannon [1983] and Balachandran [1979, 1983], and recently analyzed by Pasko [2009]. Pasko employed a model to explain the electrostatic-to-acoustic energy conversion and the initial compression waves in observed infrasonic pulses, which agrees with the observations we have made. We present thunder samples that exhibit signature infra-sound pulses at different times and acoustic source reconstruction to demonstrate the beaming effect.

Lightning activity observed in upper and lower portions of storms and its relationship to storm structure from VHF mapping and Doppler radar

NASA Technical Reports Server (NTRS)

Taylor, W. L.; Rust, W. D.; Macgorman, D. R.; Brandes, E. A.

1983-01-01

Space time mapping of very high frequencies (VHF) sources reveals lightning processes for cloud to ground (CG) and for large intracloud (IC) flashes are confined to an altitude below about 10 km and closely associated with the central high reflectivity region of a storm. Another class of IC flashes was identified that produces a splattering of small sources within the main electrically active volume of a storm and also within a large divergent wind canopy at the top of a storm. There is no apparent temporal association between the small high altitude IC flashes occurring almost continuously and the large IC and CG flashes sporadically occurring in the lower portions of storms.

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

NASA Technical Reports Server (NTRS)

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

Automated Studies of Continuing Current in Lightning Flashes

NASA Astrophysics Data System (ADS)

Martinez-Claros, Jose

Continuing current (CC) is a continuous luminosity in the lightning channel that lasts longer than 10 ms following a lightning return stroke to ground. Lightning flashes following CC are associated with direct damage to power lines and are thought to be responsible for causing lightning-induced forest fires. The development of an algorithm that automates continuing current detection by combining NLDN (National Lightning Detection Network) and LEFA (Langmuir Electric Field Array) datasets for CG flashes will be discussed. The algorithm was applied to thousands of cloud-to-ground (CG) flashes within 40 km of Langmuir Lab, New Mexico measured during the 2013 monsoon season. It counts the number of flashes in a single minute of data and the number of return strokes of an individual lightning flash; records the time and location of each return stroke; performs peak analysis on E-field data, and uses the slope of interstroke interval (ISI) E-field data fits to recognize whether continuing current (CC) exists within the interval. Following CC detection, duration and magnitude are measured. The longest observed C in 5588 flashes was 631 ms. The performance of the algorithm (vs. human judgement) was checked on 100 flashes. At best, the reported algorithm is "correct" 80% of the time, where correct means that multiple stations agree with each other and with a human on both the presence and duration of CC. Of the 100 flashes that were validated against human judgement, 62% were hybrid. Automated analysis detects the first but misses the second return stroke in many cases where the second return stroke is followed by long CC. This problem is also present in human interpretation of field change records.

GLM Proxy Data Generation: Methods for Stroke/Pulse Level Inter-Comparison of Ground-Based Lightning Reference Networks

NASA Technical Reports Server (NTRS)

Cummins, Kenneth L.; Carey, Lawrence D.; Schultz, Christopher J.; Bateman, Monte G.; Cecil, Daniel J.; Rudlosky, Scott D.; Petersen, Walter Arthur; Blakeslee, Richard J.; Goodman, Steven J.

2011-01-01

In order to produce useful proxy data for the GOES-R Geostationary Lightning Mapper (GLM) in regions not covered by VLF lightning mapping systems, we intend to employ data produced by ground-based (regional or global) VLF/LF lightning detection networks. Before using these data in GLM Risk Reduction tasks, it is necessary to have a quantitative understanding of the performance of these networks, in terms of CG flash/stroke DE, cloud flash/pulse DE, location accuracy, and CLD/CG classification error. This information is being obtained through inter-comparison with LMAs and well-quantified VLF/LF lightning networks. One of our approaches is to compare "bulk" counting statistics on the spatial scale of convective cells, in order to both quantify relative performance and observe variations in cell-based temporal trends provided by each network. In addition, we are using microsecond-level stroke/pulse time correlation to facilitate detailed inter-comparisons at a more-fundamental level. The current development status of our ground-based inter-comparison and evaluation tools will be presented, and performance metrics will be discussed through a comparison of Vaisala s Global Lightning Dataset (GLD360) with the NLDN at locations within and outside the U.S.

GLM Proxy Data Generation: Methods for Stroke/Pulse Level Inter-comparison of Ground-based Lightning Reference Networks

NASA Astrophysics Data System (ADS)

Cummins, K. L.; Carey, L. D.; Schultz, C. J.; Bateman, M. G.; Cecil, D. J.; Rudlosky, S. D.; Petersen, W. A.; Blakeslee, R. J.; Goodman, S. J.

2011-12-01

In order to produce useful proxy data for the GOES-R Geostationary Lightning Mapper (GLM) in regions not covered by VLF lightning mapping systems, we intend to employ data produced by ground-based (regional or global) VLF/LF lightning detection networks. Before using these data in GLM Risk Reduction tasks, it is necessary to have a quantitative understanding of the performance of these networks, in terms of CG flash/stroke DE, cloud flash/pulse DE, location accuracy, and CLD/CG classification error. This information is being obtained through inter-comparison with LMAs and well-quantified VLF/LF lightning networks. One of our approaches is to compare "bulk" counting statistics on the spatial scale of convective cells, in order to both quantify relative performance and observe variations in cell-based temporal trends provided by each network. In addition, we are using microsecond-level stroke/pulse time correlation to facilitate detailed inter-comparisons at a more-fundamental level. The current development status of our ground-based inter-comparison and evaluation tools will be presented, and performance metrics will be discussed through a comparison of Vaisala's Global Lightning Dataset (GLD360) with the NLDN at locations within and outside the U.S.

Infrasound from lightning measured in Ivory Coast from 2004 to 2014

NASA Astrophysics Data System (ADS)

Farges, Thomas; Le Pichon, Alexis; Ceranna, Lars; Diawara, Adama

2016-04-01

It is well established that more than 2,000 thunderstorms occur continuously around the world and that about 45 lightning flashes are produced per second over the globe. 80 % of the infrasound stations of the International Monitoring System (IMS) of the CTBTO (Comprehensive nuclear Test Ban Treaty Organisation) are now certified and routinely measure signals due to natural activity (e.g., airflow over mountains, aurora, microbaroms, surf, volcanoes, severe weather including lightning flashes …). Some of the IMS stations are located where lightning activity is high (e.g. Africa, South America). These infrasound stations are well localised to study lightning flash activity and its disparity, which is a good proxy for global warming. Progress in infrasound array data processing over the past ten years makes such lightning studies possible. Assink et al. (2008) and Farges and Blanc (2010) show clearly that it is possible to measure lightning infrasound from thunderstorms within 300 km. One-to-one correlation is possible when the thunderstorm is within about 75 km from the station. When the lightning flash occurs within 20 km, it is also possible to rebuild the 3D geometry of the discharges when the network size is less than 100 m (Arechiga et al., 2011; Gallin, 2014). An IMS infrasound station has been installed in Ivory Coast since 2002. The lightning rate of this region is 10-20 flashes/km²/year from space-based instrument OTD (Christian et al., 2003). Ivory Coast is therefore a good place to study infrasound data associated with lightning activity and its temporal variation. First statistical results will be presented in this paper based on 10 years of data (2005-2014). Correlation between infrasound having a mean frequency higher than 1 Hz and lightning flashes detected by the World Wide Lightning Location Network (WWLLN) is systematically looked for. One-to-one correlation is obtained for flashes occurring within about 100 km. An exponential decrease of the infrasound amplitude with the distance of one order of magnitude per 50 km is found. The detection variability with the arrival azimuth is examined. A non-negligible number of events coming from the shadow zone (30 - 200 km) is found. It is also interesting to note that most of the infrasound related to lightning flashes is due to thunderstorm which occurred more than 200 km away from the station. However, it is hard to deduce any precise characteristics in those cases.

NASA SPoRT GOES-R Proving Ground Activities

NASA Technical Reports Server (NTRS)

Stano, Geoffrey T.; Fuell, Kevin K.; Jedloec, Gary J.

2010-01-01

The NASA Short-term Prediction Research and Transition (SPoRT) program is a partner with the GOES-R Proving Ground (PG) helping prepare forecasters understand the unique products to come from the GOES-R instrument suite. SPoRT is working collaboratively with other members of the GOES-R PG team and Algorithm Working Group (AWG) scientists to develop and disseminate a suite of proxy products that address specific forecast problems for the WFOs, Regional and National Support Centers, and other NOAA users. These products draw on SPoRT s expertise with the transition and evaluation of products into operations from the MODIS instrument and the North Alabama Lightning Mapping Array (NALMA). The MODIS instrument serves as an excellent proxy for the Advanced Baseline Imager (ABI) that will be aboard GOES-R. SPoRT has transitioned and evaluated several multi-channel MODIS products. The true and false color products are being used in natural hazard detection by several SPoRT partners to provide better observation of land features, such as fires, smoke plumes, and snow cover. Additionally, many of SPoRT s partners are coastal offices and already benefit from the MODIS sea surface temperature composite. This, along with other surface feature observations will be developed into ABI proxy products for diagnostic use in the forecast process as well as assimilation into forecast models. In addition to the MODIS instrument, the NALMA has proven very valuable to WFOs with access to these total lightning data. These data provide situational awareness and enhanced warning decision making to improve lead times for severe thunderstorm and tornado warnings. One effort by SPoRT scientists includes a lightning threat product to create short-term model forecasts of lightning activity. Additionally, SPoRT is working with the AWG to create GLM proxy data from several of the ground based total lightning networks, such as the NALMA. The evaluation will focus on the vastly improved spatial coverage of the GLM, but with the trade-off of lower resolution compared to the NALMA. In addition to the above tasks, SPoRT will make these data available in the NWS next generation display software, AWIPS II. This has already been successfully completed for the two basic GLM proxies. SPoRT will use these products to train forecasters on the capabilities of GOES-R and foster feedback to develop additional products, visualizations, and requirements beneficial to end users needs. These developments and feedback will be made available to the GOES-R Proving Ground for the upcoming 2010 Spring Program in Norman, Oklahoma.

Infrasound from lightning measured in Ivory Coast

NASA Astrophysics Data System (ADS)

Farges, T.; Millet, C.; Matoza, R. S.

2012-04-01

It is well established that more than 2,000 thunderstorms occur continuously around the world and that about 45 lightning flashes are produced per second over the globe. More than two thirds (42) of the infrasound stations of the International Monitoring System (IMS) of the CTBTO (Comprehensive nuclear Test Ban Treaty Organisation) are now certified and routinely measure signals due to natural activity (e.g., airflow over mountains, aurora, microbaroms, surf, volcanoes, severe weather including lightning flashes, …). Some of the IMS stations are located where worldwide lightning detection networks (e.g. WWLLN) have a weak detection capability but lightning activity is high (e.g. Africa, South America). These infrasound stations are well localised to study lightning flash activity and its disparity, which is a good proxy for global warming. Progress in infrasound array data processing over the past ten years makes such lightning studies possible. For example, Farges and Blanc (2010) show clearly that it is possible to measure lightning infrasound from thunderstorms within a range of distances from the infrasound station. Infrasound from lightning can be detected when the thunderstorm is within about 75 km from the station. The motion of the squall zone is very well measured inside this zone. Up to 25% of lightning flashes can be detected with this technique, giving better results locally than worldwide lightning detection networks. An IMS infrasound station has been installed in Ivory Coast for 9 years. The lightning rate of this region is 10-20 flashes/km2/year from space-based instrument OTD (Christian et al., 2003). Ivory Coast is therefore a good place to study infrasound data associated with lightning activity and its temporal variation. First statistical results will be presented in this paper based on 4 years of data (2005-2009). For short lightning distances (less than 20 km), up to 60 % of lightning detected by WWLLN has been one-to-one correlated. Moreover, numerous infrasound events which have the infrasound from lightning signature could not be correlated when thunderstorms were close to the station. Statistical analyses of all correlated infrasound events show an exponential decrease of the infrasound amplitude with the distance of one order of magnitude per 50 km. These analyses show also that the relative position of lightning is important: the detection limit is higher when lightning occur at the East of the station than when they occur at the West. The dominant wind (the Easterlies) could be responsible of this dissymmetry. It also exists a high variability of detection efficiency with the seasons (better efficiency in fall than in spring). Finally, these statistics show clearly a structure inside the shadow zone (from 70 to 200 km away from the station). These results will be compared with intensive numerical simulations. The simulations are separated into two parts: the simulation of the near-field blast wave generated by a lightning and the simulation of the non-linear propagation of the shock front through a realistic atmosphere. By comparing our numerical results to recorded data over a full 1-year period, we aim to show that dominant features of statistics at the IMS station may be explained by the meteorological variability.

TETRA observation of gamma-rays at ground level associated with nearby thunderstorms

PubMed Central

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

2013-01-01

[1] 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. TGF and Energetic Thunderstorm Rooftop Array (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, 24 events with durations 0.02–4.2 ms 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 ms and 5 km 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. PMID:26167428

Video, LMA and ULF observations of a negative gigantic jet in North Texas

NASA Astrophysics Data System (ADS)

Bruning, E. C.; Cummer, S.; Palivec, K.; Lyons, W. A.; Chmielewski, V.; MacGorman, D. R.

2017-12-01

On 8 September 2016 at 0125:38 UTC video of a negative gigantic jet was captured from Hawley, TX. VHF Lightning Mapping Arrays in West Texas and Oklahoma also observed the parent flash (duration of about 1 s) and, for the first time, mapped dozens of points along ascending negative leaders, lasting about 50 ms, which extended well above cloud top to about 35 km MSL altitude. A few well-located VHF sources were also detected near 50 km. Together, the video and VHF observations provide additional confirmation of the altitude at which the leader-to-streamer transition takes place in gigantic jet discharges. ULF magnetic field data from the Duke iCMC network show a current excursion associated with the onset of the upward movement of negative charge and leaders in the VHF. As the gigantic jet reached its full height, current spiked to 80 kA, followed by several hundred milliseconds of continuing current of 10-20 kA. Total charge moment change was about 6000 C km. The storm complex produced predominantly negative large charge moment change events, which is characteristic of storms that produce negative gigantic jets.

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

NASA Astrophysics Data System (ADS)

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.

The Goes-R Geostationary Lightning Mapper (GLM)

NASA Technical Reports Server (NTRS)

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

2011-01-01

The Geostationary Operational Environmental Satellite (GOES-R) is the next series to follow the existing GOES system currently operating over the Western Hemisphere. Superior spacecraft and instrument technology will support expanded detection of environmental phenomena, resulting in more timely and accurate forecasts and warnings. Advancements over current GOES capabilities include a new capability for total lightning detection (cloud and cloud-to-ground flashes) from the Geostationary Lightning Mapper (GLM), and improved storm diagnostic capability with the Advanced Baseline Imager. The GLM will map total lightning activity (in-cloud and cloud-to-ground lighting flashes) continuously day and night with near-uniform spatial resolution of 8 km with a product refresh rate of less than 20 sec over the Americas and adjacent oceanic regions. This will aid in forecasting severe storms and tornado activity, and convective weather impacts on aviation safety and efficiency. In parallel with the instrument development, a GOES-R Risk Reduction Team and Algorithm Working Group Lightning Applications Team have begun to develop the Level 2 algorithms, cal/val performance monitoring tools, and new applications. Proxy total lightning data from the NASA Lightning Imaging Sensor on the Tropical Rainfall Measuring Mission (TRMM) satellite and regional test beds are being used to develop the pre-launch algorithms and applications, and also improve our knowledge of thunderstorm initiation and evolution. In this paper we will report on new Nowcasting and storm warning applications being developed and evaluated at various NOAA Testbeds.

FDTD Modeling of LEMP Propagation in the Earth-Ionosphere Waveguide With Emphasis on Realistic Representation of Lightning Source

NASA Astrophysics Data System (ADS)

Tran, Thang H.; Baba, Yoshihiro; Somu, Vijaya B.; Rakov, Vladimir A.

2017-12-01

The finite difference time domain (FDTD) method in the 2-D cylindrical coordinate system was used to compute the nearly full-frequency-bandwidth vertical electric field and azimuthal magnetic field waveforms produced on the ground surface by lightning return strokes. The lightning source was represented by the modified transmission-line model with linear current decay with height, which was implemented in the FDTD computations as an appropriate vertical phased-current-source array. The conductivity of atmosphere was assumed to increase exponentially with height, with different conductivity profiles being used for daytime and nighttime conditions. The fields were computed at distances ranging from 50 to 500 km. Sky waves (reflections from the ionosphere) were identified in computed waveforms and used for estimation of apparent ionospheric reflection heights. It was found that our model reproduces reasonably well the daytime electric field waveforms measured at different distances and simulated (using a more sophisticated propagation model) by Qin et al. (2017). Sensitivity of model predictions to changes in the parameters of atmospheric conductivity profile, as well as influences of the lightning source characteristics (current waveshape parameters, return-stroke speed, and channel length) and ground conductivity were examined.

Meteorological Aspects of Two Modes of Lightning Triggered Upward Lightning (LTUL) Events in Sprite-Producing MCSs

NASA Technical Reports Server (NTRS)

Lyons, W. A.; Nelson, T. E.; Warner, T. A.; Lang, T. J.; Cummins, K.; Quick, M.; Rison, W.; Krehbiel, P.; Cummer, S. A.; Meyers, J.;

DEVELOPMENT OF A METHOD FOR THE OBSERVATION OF LIGHTNING IN PROTOPLANETARY DISKS USING ION LINES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muranushi, Takayuki; Akiyama, Eiji; Inutsuka, Shu-ichiro

2015-12-20

In this paper, we propose observational methods for detecting lightning in protoplanetary disks. We do so by calculating the critical electric field strength in the lightning matrix gas (LMG), the parts of the disk where the electric field is strong enough to cause lightning. That electric field accelerates multiple positive ion species to characteristic terminal velocities. In this paper, we present three distinct discharge models with corresponding critical electric fields. We simulate the position–velocity diagrams and the integrated emission maps for the models. We calculate the measure-of-sensitivity values for detection of the models and for distinguishing between the models. Atmore » the distance of TW Hya (54 pc), LMG that occupies 2π in azimuth and has 25 AU < r < 50 AU is detectable at 1200σ to 4000σ. The lower limits of the radii of 5σ-detectable LMG clumps are between 1.6 AU and 5.3 AU, depending on the models.« less

GLM Post Launch Testing and Airborne Science Field Campaign

NASA Astrophysics Data System (ADS)

Goodman, S. J.; Padula, F.; Koshak, W. J.; Blakeslee, R. J.

2017-12-01

The Geostationary Operational Environmental Satellite (GOES-R) series provides the continuity for the existing GOES system currently operating over the Western Hemisphere. The Geostationary Lightning Mapper (GLM) is a wholly new instrument that provides a capability for total lightning detection (cloud and cloud-to-ground flashes). The first satellite in the GOES-R series, now GOES-16, was launched in November 2016 followed by in-orbit post launch testing for approximately 12 months before being placed into operations replacing the GOES-E satellite in December. The GLM will map total lightning continuously throughout day and night with near-uniform spatial resolution of 8 km with a product latency of less than 20 sec over the Americas and adjacent oceanic regions. The total lightning is very useful for identifying hazardous and severe thunderstorms, monitoring storm intensification and tracking evolution. Used in tandem with radar, satellite imagery, and surface observations, total lightning data has great potential to increase lead time for severe storm warnings, improve aviation safety and efficiency, and increase public safety. In this paper we present initial results from the post-launch in-orbit performance testing, airborne science field campaign conducted March-May, 2017 and assessments of the GLM instrument and science products.

A Closer Look at the Congo and the Lightning Maximum on Earth

NASA Technical Reports Server (NTRS)

Blakeslee, R. J.; Buechler, D. E.; Lavreau, Johan; Goodman, Steven J.

2008-01-01

The global maps of maximum mean annual flash density derived from a decade of observations from the Lightning Imaging Sensor on the NASA Tropical Rainfall Measuring Mission (TRMM) satellite show that a 0.5 degree x 0.5 degree pixel west of Bukavu, Democratic Republic of Congo (latitude 2S, longitude 28E) has the most frequent lightning activity anywhere on earth with an average value in excess of 157 fl/sq km/yr. This pixel has a flash density that is much greater than even its surrounding neighbors. By contrast the maximum mean annual flash rate for North America located in central Florida is only 33 fl/sq km/yr. Previous studies have shown that monthly-seasonal-annual lightning maxima on earth occur in regions dominated by coastal (land-sea breeze interactions) or topographic influences (elevated heat sources, enhanced convergence). Using TRMM, Landsat Enhanced Thematic Mapper, and Shuttle Imaging Radar imagery we further examine the unique features of this region situated in the deep tropics and dominated by a complex topography having numerous mountain ridges and valleys to better understand why this pixel, unlike any other, has the most active lightning on the planet.

Lightning climatology over Jakarta, Indonesia, based on long-term surface operational, satellite, and campaign observations

NASA Astrophysics Data System (ADS)

Mori, Shuichi; Wu, Peiming; Yamanaka, Manabu D.; Hattori, Miki; Hamada, Jun-Ichi; Arbain, Ardhi A.; Lestari, Sopia; Sulistyowati, Reni; Syamsudin, Fadli

2016-04-01

Lightning frequency over Indonesian Maritime Continent (MC) is quite high (Petersen and Rutledge 2001, Christian et al. 2003, Takayabu 2006, etc). In particular, Bogor (south of Jakarta, west Jawa) had 322 days of lightning in one year (Guinness Book in 1988). Lightning causes serious damage on nature and society over the MC; forest fore, power outage, inrush/surge currents on many kinds of electronics. Lightning climatology and meso-scale characteristics of thunderstorm over the MC, in particular over Jakarta, where social damage is quite serious, were examined. We made Statistical analysis of lightning and thunderstorm based on TRMM Lightning Image Sensor (LIS) and Global Satellite Mapping of Precipitation (GSMaP) together with long-term operational surface observation data (SYNOP) in terms of diurnal, intraseasonal, monsoonal, and interannual variations. In addition, we carried out a campaign observation in February 2015 in Bogor to obtain meso-scale structure and dynamics of thunderstorm over Jakarta to focus on graupel and other ice phase particles inside by using an X-band dual-polarimetric (DP) radar. Recently, Virts et al. (2013a, b) showed comprehensive lightning climatology based on the World Wide Lightning Location Network (WWLLN). However, they also reported problems with its detection efficiency (< 10%) and small sampling frequency (< 0.1% of the time fly over tropics) by satellites. Therefore, we firstly examine in situ lightning data based on SYNOP observed by the Indonesian Agency for Meteorology, Climatology, and Geophysics (BMKG) because lightning is quite local and sporadic phenomena. We've started to analyze lightning characteristics over Jakarta region based on SYNOP as the ground truth data and GSMaP. Variability of lightning frequency around Jakarta was affected much by local conditions, e.g., topography (elevation) and proximity to the coastline. We confirmed the lightning frequency and its diurnal variation around Jakarta were much modulated by Cross Equatorial Northerly Serge (CENS), Madden-Julian Oscillation (MJO), El Nino and Indian Ocean Dipole mode events. Some of the results were inconsistent with previous studies over the equatorial ocean because we focused on lightning over land region in west Jawa. Results from the DP radar observation during the campaign around Bogor in February 2015 are also presented. This work was supported by the Japan Society for the Promotion of Science (JSPS) KAKENHI (Grants-in-Aid for Scientific Research) grant number 25350515 and the Japan Aerospace Exploration Agency (JAXA) 7th Research Announcement (RA).

The Characteristics of Total Lightning Activity in Severe Florida Thunderstorms

NASA Technical Reports Server (NTRS)

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

1997-01-01

Severe thunderstorms are defined by specific exceedance criteria regarding either wind speed (greater than or equal to 50 kts), hailstone diameter (greater than or equal to 3/4 inch), the occurrence of a tornado, or any combination thereof. Although traditional radar signatures of severe thunderstorms have been well documented, the characteristics of associated total lightning activity (both intracloud and cloud-to-ground) of severe thunderstorms remain poorly established. The reason for this are (1) less than 1% of all storms are actually severe, (2) intracloud lightning, which is typically the dominant form of electrical discharge within thunderstorms, is not routinely measured or recorded, (3) direct visual observations of intracloud lightning are obscured during the daytime, and (4) the migratory nature of many severe thunderstorms can make the accurate detection and mapping of intracloud lightning difficult when using fixed-location sensors. The recent establishment of LISDAD (Lightning Imaging Sensor Data Acquisition and Display - discussed in Goodman et al, this Meeting) has substantially addressed these limitations in east central Florida (ECFL). Analysis of total lightning flash Count histories using the LDAR (Lightning Detection And Ranging) system for known severe thunderstorms (currently irrespective of seasonal aspects and severe storm-type) has revealed flash rates exceeding 1 per second. This appears to be a necessary, but not sufficient,condition for most ECFL severe storm cases. The differences in radar-observed storm structure for high flash rate storms (to include both severe and non-severe categories) will be described together with the timing of peak flash rate vs. the timing of the severe weather manifestation. Comparisons with the satellite-bases OTD (Optical Transient Detector) overhead passes will also be presented when possible.

Lightning Detection Efficiency Analysis Process: Modeling Based on Empirical Data

NASA Technical Reports Server (NTRS)

Rompala, John T.

2005-01-01

A ground based lightning detection system employs a grid of sensors, which record and evaluate the electromagnetic signal produced by a lightning strike. Several detectors gather information on that signal s strength, time of arrival, and behavior over time. By coordinating the information from several detectors, an event solution can be generated. That solution includes the signal s point of origin, strength and polarity. Determination of the location of the lightning strike uses algorithms based on long used techniques of triangulation. Determination of the event s original signal strength relies on the behavior of the generated magnetic field over distance and time. In general the signal from the event undergoes geometric dispersion and environmental attenuation as it progresses. Our knowledge of that radial behavior together with the strength of the signal received by detecting sites permits an extrapolation and evaluation of the original strength of the lightning strike. It also limits the detection efficiency (DE) of the network. For expansive grids and with a sparse density of detectors, the DE varies widely over the area served. This limits the utility of the network in gathering information on regional lightning strike density and applying it to meteorological studies. A network of this type is a grid of four detectors in the Rondonian region of Brazil. The service area extends over a million square kilometers. Much of that area is covered by rain forests. Thus knowledge of lightning strike characteristics over the expanse is of particular value. I have been developing a process that determines the DE over the region [3]. In turn, this provides a way to produce lightning strike density maps, corrected for DE, over the entire region of interest. This report offers a survey of that development to date and a record of present activity.

Open Circuit Resonant (SansEC) Sensor Technology for Lightning Mitigation and Damage Detection and Diagnosis for Composite Aircraft Applications

NASA Technical Reports Server (NTRS)

Szatkowski, George N.; Dudley, Kenneth L.; Smith, Laura J.; Wang, Chuantong; Ticatch, Larry A.

2014-01-01

Traditional methods to protect composite aircraft from lightning strike damage rely on a conductive layer embedded on or within the surface of the aircraft composite skin. This method is effective at preventing major direct effect damage and minimizes indirect effects to aircraft systems from lightning strike attachment, but provides no additional benefit for the added parasitic weight from the conductive layer. When a known lightning strike occurs, the points of attachment and detachment on the aircraft surface are visually inspected and checked for damage by maintenance personnel to ensure continued safe flight operations. A new multi-functional lightning strike protection (LSP) method has been developed to provide aircraft lightning strike protection, damage detection and diagnosis for composite aircraft surfaces. The method incorporates a SansEC sensor array on the aircraft exterior surfaces forming a "Smart skin" surface for aircraft lightning zones certified to withstand strikes up to 100 kiloamperes peak current. SansEC sensors are open-circuit devices comprised of conductive trace spiral patterns sans (without) electrical connections. The SansEC sensor is an electromagnetic resonator having specific resonant parameters (frequency, amplitude, bandwidth & phase) which when electromagnetically coupled with a composite substrate will indicate the electrical impedance of the composite through a change in its resonant response. Any measureable shift in the resonant characteristics can be an indication of damage to the composite caused by a lightning strike or from other means. The SansEC sensor method is intended to diagnose damage for both in-situ health monitoring or ground inspections. In this paper, the theoretical mathematical framework is established for the use of open circuit sensors to perform damage detection and diagnosis on carbon fiber composites. Both computational and experimental analyses were conducted to validate this new method and system for aircraft composite damage detection and diagnosis. Experimental test results on seeded fault damage coupons and computational modeling simulation results are presented. This paper also presents the shielding effectiveness along with the lightning direct effect test results from several different SansEC LSP and baseline protected and unprotected carbon fiber reinforced polymer (CFRP) test panels struck at 40 and 100 kiloamperes following a universal common practice test procedure to enable damage comparisons between SansEC LSP configurations and common practice copper mesh LSP approaches. The SansEC test panels were mounted in a LSP test bed during the lightning test. Electrical, mechanical and thermal parameters were measured during lightning attachment and are presented with post test nondestructive inspection comparisons. The paper provides correlational results between the SansEC sensors computed electric field distribution and the location of the lightning attachment on the sensor trace and visual observations showing the SansEC sensor's affinity for dispersing the lightning attachment.

KSC-06pd1719

NASA Image and Video Library

2006-08-02

KENNEDY SPACE CENTER, FLA. - Reflected in the nearby pool of water, Space Shuttle Atlantis, propelled by the crawler-transporter, arrives on the hard stand on Launch Pad 39B. Atop the fixed service structure at right can be seen the 80-foot lightning mast that helps provide lightning protection. The slow speed of the crawler results in a 6- to 8-hour trek to the pad approximately 4 miles away. Atlantis' launch window begins Aug. 27 for an 11-day mission to the International Space Station. The STS-115 crew of six astronauts will continue construction of the station and install their cargo, the Port 3/4 truss segment with its two large solar arrays. Photo credit: NASA/Tony Gray

Low-cost modular array-field designs for flat-panel and concentrator photovoltaic systems

NASA Astrophysics Data System (ADS)

Post, H. N.; Carmichael, D. C.; Alexander, G.; Castle, J. A.

1982-09-01

Described are the design and development of low-cost, modular array fields for flat-panel and concentrator photovoltaic (PV) systems. The objective of the work was to reduce substantially the cost of the array-field Balance-of-System (BOS) subsystems and site-specific design costs as compared to previous PV installations. These subsystems include site preparation, foundations, support structures, electrical writing, grounding, lightning protection, electromagnetic interference considerations, and controls. To reduce these BOS and design costs, standardized modular (building-block) designs for flat-panel and concentrator array fields have been developed that are fully integrated and optimized for lowest life-cycle costs. Using drawings and specifications now available, these building-block designs can be used in multiples to install various size array fields. The developed designs are immediately applicable (1982) and reduce the array-field BOS costs to a fraction of previous costs.

Ionospheric effects of thunderstorms and lightning

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lay, Erin H.

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.more » 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.« less

The Design and Evaluation of the Lighting Imaging Sensor Data Applications Display (LISDAD)

NASA Technical Reports Server (NTRS)

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

1998-01-01

The design and evaluation of the Lightning Imaging Sensor Data Applications Display (LISDAD). The ultimate goal of the LISDAD system is to quantify the utility of total lightning information in short-term, severe-weather forecasting operations. To this end, scientists from NASA, NWS, and MIT organized an effort to study the relationship of lightning and severe-weather on a storm-by-storm, and even cell-by-cell basis for as many storms as possible near Melbourne, Florida. Melbourne was chosen as it offers a unique combination of high probability of severe weather and proximity to major relevant sensors - specifically: NASA's total lightning mapping system at Kennedy Space Center (the LDAR system at KSC); a NWS/NEXRAD radar (at Melbourne); and a prototype Integrated Terminal Weather System (ITWS, at Orlando), which obtains cloud-to-ground lightning Information from the National Lightning Detection Network (NLDN), and also uses NSSL's Severe Storm Algorithm (NSSL/SSAP) to obtain information about various storm-cell parameters. To assist in realizing this project's goal, an interactive, real-time data processing system (the LISDAD system) has been developed that supports both operational short-term weather forecasting and post facto severe-storm research. Suggestions have been drawn from the operational users (NWS/Melbourne) in the design of the data display and its salient behavior. The initial concept for the users Graphical Situation Display (GSD) was simply to overlay radar data with lightning data, but as the association between rapid upward trends in the total lightning rate and severe weather became evident, the display was significantly redesigned. The focus changed to support the display of time series of storm-parameter data and the automatic recognition of cells that display rapid changes in the total-lightning flash rate. The latter is calculated by grouping discrete LDAR radiation sources into lightning flashes using a time-space association algorithm. Specifically, the GSD presents the user with the Composite Maximum Reflectivity obtained from the NWS/NEXRAD. Superimposed upon this background image are placed small black circles indicating the locations of storm cells identified by the NSSL/SSA. The circles become cyan if lightning is detected within the storm-cell; if the cell has lightning rates indicative of a severe-storm, the circle turns red. This paper will: (1) review the design of LISDAD system; (2) present some examples of its data display; and shown results of the lightning based severe-weather prediction algorithm.

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

NASA Technical Reports Server (NTRS)

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

The GOES-R Geostationary Lightning Mapper (GLM)

NASA Astrophysics Data System (ADS)

Goodman, S. J.; Blakeslee, R. J.; Koshak, W. J.; Mach, D. M.; Bailey, J. C.; Buechler, D. E.; Carey, L. D.; Schultz, C. J.; Bateman, M. G.; McCaul, E., Jr.; Stano, G. T.

2012-12-01

The Geostationary Operational Environmental Satellite (GOES-R) series provides the continuity for the existing GOES system currently operating over the Western Hemisphere. New and improved instrument technology will support expanded detection of environmental phenomena, resulting in more timely and accurate forecasts and warnings. Advancements over current GOES include a new capability for total lightning detection (cloud and cloud-to-ground flashes) from the Geostationary Lightning Mapper (GLM), and improved temporal, spatial, and spectral resolution for the next generation Advanced Baseline Imager (ABI). The GLM will map total lightning activity (in-cloud and cloud-to-ground lightning flashes) continuously day and night with near-uniform spatial resolution of 8 km with a product refresh rate of less than 20 sec over the Americas and adjacent oceanic regions. This will aid in forecasting severe storms and tornado activity, and convective weather impacts on aviation safety and efficiency among a number of potential applications. In parallel with the instrument development, an Algorithm Working Group (AWG) Lightning Detection Science and Applications Team developed the Level 2 (stroke and flash) algorithms from the Level 1 lightning event (pixel level) data. Proxy data sets used to develop the GLM operational algorithms as well as cal/val performance monitoring tools were derived from the NASA Lightning Imaging Sensor (LIS) and Optical Transient Detector (OTD) instruments in low earth orbit, and from ground-based lightning networks and intensive pre-launch field campaigns. GLM will produce the same or similar lightning flash attributes provided by the LIS and OTD, and thus extends their combined climatology over the western hemisphere into the coming decades. Science and application development along with pre-operational product demonstrations and evaluations at NWS forecast offices and NOAA testbeds will prepare the forecasters to use GLM as soon as possible after the planned launch and check-out of GOES-R in late 2015. New applications will use GLM alone, in combination with the ABI, or integrated (fused) with other available tools (weather radar and ground strike networks, nowcasting systems, mesoscale analysis, and numerical weather prediction models) in the hands of the forecaster responsible for issuing more timely and accurate forecasts and warnings. Results from recent field campaigns and forecaster evaluations on the utility of the total lightning products will be presented.

Multiple Convective Cell Identification and Tracking Algorithm for documenting time-height evolution of measured polarimetric radar and lightning properties

NASA Astrophysics Data System (ADS)

Rosenfeld, D.; Hu, J.; Zhang, P.; Snyder, J.; Orville, R. E.; Ryzhkov, A.; Zrnic, D.; Williams, E.; Zhang, R.

2017-12-01

A methodology to track the evolution of the hydrometeors and electrification of convective cells is presented and applied to various convective clouds from warm showers to super-cells. The input radar data are obtained from the polarimetric NEXRAD weather radars, The information on cloud electrification is obtained from Lightning Mapping Arrays (LMA). The development time and height of the hydrometeors and electrification requires tracking the evolution and lifecycle of convective cells. A new methodology for Multi-Cell Identification and Tracking (MCIT) is presented in this study. This new algorithm is applied to time series of radar volume scans. A cell is defined as a local maximum in the Vertical Integrated Liquid (VIL), and the echo area is divided between cells using a watershed algorithm. The tracking of the cells between radar volume scans is done by identifying the two cells in consecutive radar scans that have maximum common VIL. The vertical profile of the polarimetric radar properties are used for constructing the time-height cross section of the cell properties around the peak reflectivity as a function of height. The LMA sources that occur within the cell area are integrated as a function of height as well for each time step, as determined by the radar volume scans. The result of the tracking can provide insights to the evolution of storms, hydrometer types, precipitation initiation and cloud electrification under different thermodynamic, aerosol and geographic conditions. The details of the MCIT algorithm, its products and their performance for different types of storm are described in this poster.

Spatial-temporal characteristics of lightning flash size in a supercell storm

NASA Astrophysics Data System (ADS)

Zhang, Zhixiao; Zheng, Dong; Zhang, Yijun; Lu, Gaopeng

2017-11-01

The flash sizes of a supercell storm, in New Mexico on October 5, 2004, are studied using the observations from the New Mexico Lightning Mapping Array and the Albuquerque, New Mexico, Doppler radar (KABX). First, during the temporal evolution of the supercell, the mean flash size is anti-correlated with the flash rate, following a unary power function, with a correlation coefficient of - 0.87. In addition, the mean flash size is linearly correlated with the area of reflectivity > 30 dBZ at 5 km normalized by the flash rate, with a correlation coefficient of 0.88. Second, in the horizontal, flash size increases along the direction from the region near the convection zone to the adjacent forward anvil. The region of minimum flash size usually corresponds to the region of maximum flash initiation and extent density. The horizontal correspondence between the mean flash size and the flash extent density can also be fitted by a unary power function, and the correlation coefficient is > 0.5 in 50% of the radar volume scans. Furthermore, the quality of fit is positively correlated to the convective intensity. Third, in the vertical direction, the height of the maximum flash initiation density is close to the height of maximum flash extent density, but corresponds to the height where the mean flash size is relatively small. In the discussion, the distribution of the small and dense charge regions when and where convection is vigorous in the storm, is deduced to be responsible for the relationship that flash size is temporally and spatially anti-correlated with flash rate and density, and the convective intensity.

Development of charge structure in a short live convective cell observed by a 3D lightning mapper and a phased array radar

NASA Astrophysics Data System (ADS)

Yoshida, S.; Adachi, T.; Kusunoki, K.; Wu, T.; Ushio, T.; Yoshikawa, E.

2015-12-01

Thunderstorm observation has been conducted in Osaka, Japan, with a use of a 3D lightning mapper, called Broadband Observation network for Lightning and Thunderstorm (BOLT), and an X-band phased array radar (PAR). BOLT is a LF sensor network that receives LF emission associated with lightning discharges and locates LF radiation sources in 3D. PAR employs mechanical and electrical scans, respectively, in azimuthal and elevation direction, succeeding in quite high volume scan rate. In this presentation, we focus on lightning activity and charge structure in convective cells that lasted only short time (15 minutes or so). Thunderstorms that consisted of several convective cells developed near the radar site. Precipitation structure of a convective cell in the thunderstorm was clearly observed by PAR. A reflectivity core of the convective cell appeared at an altitude of 6 km at 2245 (JST). After that the core descended and reached the ground at 2256 (JST), resulting in heavy precipitation on surface. The echo top height (30dBZ) increased intermittently between 2245 (JST) and 2253 (JST) and it reached at the altitude of 12 km. The convective cell dissipated at 2300. Many intra-cloud (IC) flashes were initiated within the convective cell. Most IC flashes that were initiated in the convective cell occurred during the time when the echo top height increased, while a few IC flashes were initiated in the convective cell after the cease of the echo top vertical development. These facts indicate that strong updraft at upper levels (about 8 km or higher) plays an important role on thunderstorm electrification for IC flashes. Moreover, initiation altitudes of the IC flashes and the positive charge regions removed by the IC flashes increased, as the echo top height increased. This fact implies that the strong updraft at the upper levels blew up positively-charged ice pellets and negatively-charged graupel, and lifted IC flash initiation altitudes and positive charge regions. Previous observation results showed that positive charge regions sometimes moved upward in short time (about 5 minutes or so) in vigorous convective cells. Our observation results support the previous observation results and show that the rapid charge structure change was caused by strong updraft at upper levels in the convective cell.

Lighting Observations During the Mt. Augustine Volcanic Eruptions With the Portable Lightning Mapping Stations

NASA Astrophysics Data System (ADS)

Rison, W.; Krehbiel, P.; Thomas, R.; Edens, H.; Aulich, G.; O'Connor, N.; Kieft, S.; McNutt, S.; Tytgat, G.; Clark, E.

2006-12-01

Following the initial eruptions of Mt. Augustine on January 11-17 2006, we quickly prepared and deployed a first contingent of two portable mapping stations. This was our first use of the newly-developed portable stations, and we were able to deploy them in time to observe the second set of explosive eruptions during the night of January~27-28. The stations were located 17~km apart on the west coast of the Kenai Peninsula, 100~km distant from Augustine on the far western side of Cook Inlet. The stations comprised a minimal network capable of determining the azimuthal direction of VHF radiation sources from electrical discharges, and thus the transverse location of the electrical activity relative to the volcano. The time series data from the southern, Homer station for the initial, energetic explosion at 8:31 pm on January~27 revealed the occurrence of spectacular lightning, which from the two-station data drifted southward from Augustine with time, in the same direction as the plume from the eruption. About 300 distinct lightning discharges occurred over an 11-minute time interval, beginning 2-3~min after the main explosion. The lightning quickly became increasingly complex with time and developed large horizontal extents. One of the final discharges of the sequence lasted 600~ms and had a transverse extent of 15~km, extending to 22~km south of Augustine's summit. In addition to this more usual form of lightning, continuous bursts of radio frequency radiation occurred during the explosion itself, indicating that the tephra was highly charged upon being ejected from the volcano. A completely unplanned and initially missed but one of several fortuitous aspects of the observations was that the Homer station functioned as a 'sea-surface interferometer' whose interference pattern can be used to determine the altitude variation with time for some discharges. The station's VHF antenna was located on the edge of a bluff 210~m above Cook Inlet and received both the direct and reflected signals from the water surface. A clear pattern of interference fringes was observed for the strongest lightning event during the explosive phase and has shown that it was an upward-triggered discharge that propagated upward from Augustine's summit and into the downwind plume. The radiation sources were characteristic of negative polarity breakdown into inferred positive charge in the plume. None of the lightning activity from the January~27-28 eruptions was observed visually due to stormy weather conditions.

Geometrical Effects on the Electromagnetic Radiation from Lightning Return Strokes

NASA Technical Reports Server (NTRS)

Willett, John C.; Smith, David A.; LeVine, David M.; Zukor, Dorothy J. (Technical Monitor)

2000-01-01

The Los Alamos National Laboratory (LANL) Sferic Array has recorded electric-field-change waveforms simultaneously at several stations surrounding the ground-strike points of numerous return strokes in cloud-to-ground lightning flashes. Such data are available from the five-station sub-networks in both Florida and New Mexico. With these data it has been possible for the first time to compare the waveforms radiated in different directions by a given stroke. Such comparisons are of interest to assess both the effects of channel geometry on the fine structure of subsequent-stroke radiation fields and the role of branches in the more jagged appearance of first-stroke waveforms. This paper presents multiple-station, time-domain waveforms with a 200 Hz to 500 kHz pass-band from both first and subsequent return strokes at ranges generally between 100 and 200 km. The differences among waveforms of the same stroke received at stations in different directions from the lightning channel are often obvious. These differences are illustrated and interpreted in the context of channel tortuosity and branches.

LNOx Estimates Directly from LIS Data

NASA Astrophysics Data System (ADS)

Koshak, W. J.; Vant-hull, B.; McCaul, E.

2014-12-01

Nitrogen oxides (NOx = NO + NO2) are known to indirectly influence climate since they affect the concentration of both atmospheric ozone (O3) and hydroxyl radicals (OH). In addition, lightning NOx (LNOx) is the most important source of NOx in the upper troposphere (particularly in the tropics). It is difficult to estimate LNOx because it is not easy to make measurements near the lightning channel, and the various NOx-producing mechanisms within a lightning flash are not fully understood. A variety of methods have been used to estimate LNOx production [e.g., in-situ observations, combined ground-based VHF lightning mapping and VLF/LF lightning locating observations, indirect retrievals using satellite Ozone Monitoring Instrument (OMI) observations, theoretical considerations, laboratory spark measurements, and rocket triggered lightning measurements]. The present study introduces a new approach for estimating LNOx that employs Lightning Imaging Sensor (LIS) data. LIS optical measurements are used to directly estimate the total energy of a flash; the total flash energy is then converted to LNOx production (in moles) by multiplying by a thermo-chemical yield. Hence, LNOx estimates on a flash-by-flash basis are obtained. A Lightning NOx Indicator (LNI) is computed by summing up the LIS-derived LNOx contributions from a region over a particular analysis period. Larger flash optical areas are consistent with longer channel length and/or more energetic channels, and hence more NOx production. Brighter flashes are consistent with more energetic channels, and hence more NOx production. The location of the flash within the thundercloud and the optical scattering characteristics of the thundercloud are complicating factors. LIS data for the years 2003-2013 were analyzed, and geographical plots of the time-evolution of the LNI over the southern tier states (i.e. upto 38o N) of CONUS were determined. Overall, the LNI trends downward over the 11 yr analysis period. The LNI has been added to the list of indicators presently provided by a sustaining assessment tool developed at the NASA Marshall Space Flight Center (MSFC) for monitoring lightning/climate interactions over the United States, as part of the National Climate Assessment (NCA) program.

The GOES-R Geostationary Lightning Mapper (GLM)

NASA Astrophysics Data System (ADS)

Goodman, Steven J.; Blakeslee, Richard J.; Koshak, William J.; Mach, Douglas; Bailey, Jeffrey; Buechler, Dennis; Carey, Larry; Schultz, Chris; Bateman, Monte; McCaul, Eugene; Stano, Geoffrey

2013-05-01

The Geostationary Operational Environmental Satellite R-series (GOES-R) is the next block of four satellites to follow the existing GOES constellation currently operating over the Western Hemisphere. Advanced spacecraft and instrument technology will support expanded detection of environmental phenomena, resulting in more timely and accurate forecasts and warnings. Advancements over current GOES capabilities include a new capability for total lightning detection (cloud and cloud-to-ground flashes) from the Geostationary Lightning Mapper (GLM), and improved cloud and moisture imagery with the 16-channel Advanced Baseline Imager (ABI). The GLM will map total lightning activity continuously day and night with near-uniform storm-scale spatial resolution of 8 km with a product refresh rate of less than 20 s over the Americas and adjacent oceanic regions in the western hemisphere. This will aid in forecasting severe storms and tornado activity, and convective weather impacts on aviation safety and efficiency. In parallel with the instrument development, an Algorithm Working Group (AWG) Lightning Detection Science and Applications Team developed the Level 2 (stroke and flash) algorithms from the Level 1 lightning event (pixel level) data. Proxy data sets used to develop the GLM operational algorithms as well as cal/val performance monitoring tools were derived from the NASA Lightning Imaging Sensor (LIS) and Optical Transient Detector (OTD) instruments in low Earth orbit, and from ground-based lightning networks and intensive prelaunch field campaigns. The GLM will produce the same or similar lightning flash attributes provided by the LIS and OTD, and thus extend their combined climatology over the western hemisphere into the coming decades. Science and application development along with preoperational product demonstrations and evaluations at NWS forecast offices and NOAA testbeds will prepare the forecasters to use GLM as soon as possible after the planned launch and checkout of GOES-R in late 2015. New applications will use GLM alone, in combination with the ABI, or integrated (fused) with other available tools (weather radar and ground strike networks, nowcasting systems, mesoscale analysis, and numerical weather prediction models) in the hands of the forecaster responsible for issuing more timely and accurate forecasts and warnings.

Characteristics of NLDN-Reported Radio Frequency Emissions Associated with Terrestrial Gamma-ray Flashes

NASA Astrophysics Data System (ADS)

Mailyan, B. G.; Nag, A.; Murphy, M. J.; Briggs, M. S.; Dwyer, J. R.; Cramer, E.; Stanbro, M.; Roberts, O. J.; Rassoul, H.

2017-12-01

Electric and magnetic field signals in the radio frequency range associated with Terrestrial Gamma-ray Flashes (TGFs) have become important measurements for studying this high-energy atmospheric phenomenon. These signals can be used to geolocate the source of TGFs, but they also provide insights into the TGF production mechanism, and the relationship between particle fluxes and lightning. In this study, we analyze 32 TGFs detected by the Fermi Gamma-ray Burst Monitor (GBM) occurring in 2014-2016 in conjunction with data from the U.S. National Lightning Detection Network (NLDN). We examine the characteristics of magnetic field waveforms measured by NLDN sensors for 48 pulses occurring within 5 ms of the peak-time of the gamma-ray photon flux. The -3 dB bandwidth of the NLDN sensors are from about 400 Hz to 400 KHz. For 15 (out of 32) TGFs, the associated NLDN pulse occurred almost simultaneously with (that is, within 300 μs of) the TGF. It is possible that these near-simultaneous low frequency magnetic field pulses were produced by relativistic electron beams. The median time interval between the beginning of these near-simultaneous NLDN pulses and the peak-times of the TGF flux is 38 μs. 3 out of 16 ( 19%) of these pulses had negative initial polarity. The absolute value of NLDN-estimated peak currents, which can be viewed as a quantity proportional to the peak magnetic radiation field of these pulses, ranges from 17 kA to 166 kA, with the median being 32 kA. Twelve pulses had peak currents less than 50 kA. Additionally, we will compare the characteristics of GBM-reported gamma-ray signatures of the two categories of TGFs, those with a near-simultaneous NLDN-detected pulse and those with no such pulse (but with other pulses detected by the NLDN occurring within 5 ms of the TGF). Also, one of the TGFs occurred within the coverage region of the Kennedy Space Center Lightning Mapping Array (LMA). We will examine in detail the LMA, NLDN, and NEXRAD radar data for this TGF.

Flash Location, Size, and Rates Relative to the Evolving Kinematics and Microphysics of the 29 May 2012 DC3 Supercell Storm

NASA Astrophysics Data System (ADS)

MacGorman, D. R.; DiGangi, E.; Ziegler, C.; Biggerstaff, M. I.; Betten, D.; Bruning, E. C.

2014-12-01

A supercell thunderstorm was observed on 29 May 2012 during the Deep Convective Clouds and Chemistry (DC3) experiment. This storm was part of a cluster of severe storms and produced 5" hail, an EF-1 tornado, and copious lightning over the course of a few hours. During a period in which flash rates were increasing rapidly, observations were obtained from mobile polarimetric radars and a balloon-borne electric field meter (EFM) and particle imager, while aircraft sampled the chemistry of the inflow and anvil. In addition, the storm was within the domain of the 3-dimensional Oklahoma Lightning Mapping Array (LMA) and the S-band KTLX WSR-88D radar. The focus of this paper is the evolution of flash rates, the location of flash initiations, and the distribution of flash size and flash extent density as they relate to the evolving kinematics and microphysics of the storm for the approximately 30-minute period in which triple-Doppler coverage was available. Besides analyzing reflectivity structure and three-dimensional winds for the entire period, we examine mixing ratios of cloud water, cloud ice, rain, and graupel/hail that have been retrieved by a Lagrangian analysis for three select times, one each at the beginning, middle, and end of the period. Flashes in an around the updraft of this storm were typically small. Flash size tended to increase, and flash rates tended to decrease as distance from the updraft increased. Although flash initiations were most frequent near the updraft, some flashes were initiated near the edge of 30 dBZ cores and propagated into the anvil. Later, some flashes were initiated in the anvil itself, in vertical cells that formed and became electrified tens of kilometers downshear of the main body of the storm. Considerable lightning structure was inferred to be in regions dominated by cloud ice in the upper part of the storm. The continual small discharges in the overshooting top of the storm tended to be near or within 15 dBZ contours, although occasional discharges appeared to extend above the storm.

Preliminary lightning observations over Greece

NASA Astrophysics Data System (ADS)

Chronis, Themis G.

2012-02-01

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

Development of the Langmuir Electric Field Array (LEFA)

NASA Astrophysics Data System (ADS)

Sonnenfeld, R. G.; Eack, K.; Eastvedt, E.; Edens, H. E.; Hager, W. W.; Hunyady, S.; Alvidrez, V.; Lapierre, J.; Morris, K.; Vaive, G.; Wang, T.; Zhang, J.

2009-12-01

An electric-field-change (ΔE) sensor (also called a ``slow antenna'') is a long proven instrument in atmospheric electricity research. While there is still value to be derived from single-station measurements of ΔE, multi-station measurements better constrain the data interpretation. Modern publications still cite the work of Krehbiel [et al] for the insights gleaned from the 8-station array they deployed in 1979. In particular, with four independent measurements, one can locate the center of charge discharged in a cloud-to-ground (CG) flash. With seven measurements, one can locate the two charge centers connected during an intra-cloud (IC) flash. The measurements become more interesting when multi-station ΔE data is combined with radio-frequency emission data from a lightning mapping array (LMA). The ΔE array allows an independent check of the assumptions about charge layers made in the interpretation of LMA data, as well as giving greater visibility into the effects of positive streamers. The Langmuir Electric Field Array (LEFA) is designed to accommodate the very large amplitude range of ΔE data characteristic of lightning. Such design is more important in an array than a single station, as the goal is explicitly to correlate data from ten stations spaced some kilometers apart. To address the dynamic range challenge, every ΔE sensor is a set of three independent sensors, integrated into a 19-inch-steel-mixing bowl. The electronic gain is a factor of 4 greater for the sensitive (S) channel than for the medium (M) channel, and 20X greater for the (S) channel compared to the insensitive (I) channel. Further, the electrode sensor areas decrease by factors of 5, moving from S, to M, to I, so that the (S) channel is hundreds of times more sensitive than the (I) channel. Since each channel is digitized with 16-bits of resolution, the ideal full range of the instrument is roughly equal to a single channel digitized at 24 bits. Digitizing the same signal at three sensitivities also turns out to be useful in identifying noise sources and separating unusual ΔE effects from instrumental noise. The LEFA was also designed for rapid data integration and processing. All three channels of ΔE data are continuously digitized with embedded PC-104 computers (along with timing data) at 50 kSamples/second and streamed to large hard-drives. Instruments are linked by a 802.11 wireless network, and a network broadcast protocol enables central control. During fair-weather, the controller tells all instruments to shut down and to do a first pass analysis of their own data, discarding periods of electrical inactivity, and imaging all interesting data. While the full precision data occupies 24~Mbytes/minute, the quick images are 20~kBytes/min, and are automatically uploaded to a web-server. We learned over a summer of operation that this method is workable, and allows one student to wrangle the data from the entire network. We are currently working toward a full deployment, hopefully before local electrical activity ends for the season.

Severe storm electricity

NASA Technical Reports Server (NTRS)

Rust, W. D.; Macgorman, D. R.

1985-01-01

During FY-85, Researchers conducted a field program and analyzed data. The field program incorporated coordinated measurements made with a NASA U2. Results include the following: (1) ground truth measurements of lightning for comparison with those obtained by the U2; (2) analysis of dual-Doppler radar and dual-VHF lightning mapping data from a supercell storm; (3) analysis of synoptic conditions during three simultaneous storm systems on 13 May 1983 when unusually large numbers of positive cloud-to-ground (+CG) flashes occurred; (4) analysis of extremely low frequency (ELF) wave forms; and (5) an assessment of a cloud -ground strike location system using a combination of mobile laboratory and fixed-base TV video data.

Lightning activity and severe storm structure

NASA Technical Reports Server (NTRS)

Taylor, W. L.; Brandes, E. A.; Rust, W. D.; Macgorman, D. R.

1984-01-01

Space-time mapping of VHF sources from four severe storms on June 19, 1980 reveals that lightning processes for cloud-to-ground (CG) and large intracloud (IC) flashes are confined to an altitude below about 10 km and closely associated with the central regions of high reflectivity. Another class of IC flashes produces a splattering of sources within the storms' main electrically active volumes and also within the large divergent wind canopy aloft. There is no apparent temporal association between the small high altitude IC flashes that occur almost continuously and the large IC and CG flashes that occur sporadically in the lower portions of storms.

Mapping lightning discharges on Earth with lightning-generated whistlers wave emission in space and their effects on radiation belt electrons

NASA Astrophysics Data System (ADS)

Farges, T.; Ripoll, J. F.; Santolik, O.; Kolmasova, I.; Kurth, W. S.; Hospodarsky, G. B.; Kletzing, C.

2017-12-01

It is widely accepted that the slot region of the Van Allen radiation belts is sculpted by the presence of whistler mode waves especially by plasmaspheric hiss emissions. In this work, we investigate the role of lightning-generated whistler waves (LGW), which also contribute to scatter electrons trapped in the plasmaphere but, in general, to a lesser extent due to their low mean amplitude and occurrence rate. Our goal is to revisit the characterization of LGW occurrence in the Earth's atmosphere and in space as well as the computation of LGW effects by looking at a series of particular events, among which intense events, in order to characterize maximal scattering effects. We use multicomponent measurements of whistler mode waves by the Waves instrument of Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) onboard the Van Allen Probes spacecraft as our primary data source. We combine this data set with local measurements of the plasma density. We also use the data of the World Wide Lightning Location Network in order to localize the source of lightning discharges on Earth and their radiated energy, both locally at the footprint of the spacecraft and, globally, along the drift path. We discuss how to relate the signal measured in space with the estimation of the power emitted in the atmosphere and the associated complexity. Using these unique data sets we model the coefficients of quasi-linear pitch angle diffusion and we estimate effects of these waves on radiation belt electrons. We show evidence that lightning generated whistlers can, at least in some cases, influence the radiation belt dynamics.

SciSpark: In-Memory Map-Reduce for Earth Science Algorithms

NASA Astrophysics Data System (ADS)

Ramirez, P.; Wilson, B. D.; Whitehall, K. D.; Palamuttam, R. S.; Mattmann, C. A.; Shah, S.; Goodman, A.; Burke, W.

2016-12-01

We are developing a lightning fast Big Data technology called SciSpark based on ApacheTM Spark under a NASA AIST grant (PI Mattmann). Spark implements the map-reduce paradigm for parallel computing on a cluster, but emphasizes in-memory computation, "spilling" to disk only as needed, and so outperforms the disk-based Apache Hadoop by 100x in memory and by 10x on disk. SciSpark extends Spark to support Earth Science use in three ways: Efficient ingest of N-dimensional geo-located arrays (physical variables) from netCDF3/4, HDF4/5, and/or OPeNDAP URLS; Array operations for dense arrays in scala and Java using the ND4S/ND4J or Breeze libraries; Operations to "split" datasets across a Spark cluster by time or space or both. For example, a decade-long time-series of geo-variables can be split across time to enable parallel "speedups" of analysis by day, month, or season. Similarly, very high-resolution climate grids can be partitioned into spatial tiles for parallel operations across rows, columns, or blocks. In addition, using Spark's gateway into python, PySpark, one can utilize the entire ecosystem of numpy, scipy, etc. Finally, SciSpark Notebooks provide a modern eNotebook technology in which scala, python, or spark-sql codes are entered into cells in the Notebook and executed on the cluster, with results, plots, or graph visualizations displayed in "live widgets". We have exercised SciSpark by implementing three complex Use Cases: discovery and evolution of Mesoscale Convective Complexes (MCCs) in storms, yielding a graph of connected components; PDF Clustering of atmospheric state using parallel K-Means; and statistical "rollups" of geo-variables or model-to-obs. differences (i.e. mean, stddev, skewness, & kurtosis) by day, month, season, year, and multi-year. Geo-variables are ingested and split across the cluster using methods on the sciSparkContext object including netCDFVariables() for spatial decomposition and wholeNetCDFVariables() for time-series. The presentation will cover the architecture of SciSpark, the design of the scientific RDD (sRDD) data structures for N-dim. arrays, results from the three science Use Cases, example Notebooks, lessons learned from the algorithm implementations, and parallel performance metrics.

Automated installation methods for photovoltaic arrays

NASA Astrophysics Data System (ADS)

Briggs, R.; Daniels, A.; Greenaway, R.; Oster, J., Jr.; Racki, D.; Stoeltzing, R.

1982-11-01

Since installation expenses constitute a substantial portion of the cost of a large photovoltaic power system, methods for reduction of these costs were investigated. The installation of the photovoltaic arrays includes all areas, starting with site preparation (i.e., trenching, wiring, drainage, foundation installation, lightning protection, grounding and installation of the panel) and concluding with the termination of the bus at the power conditioner building. To identify the optimum combination of standard installation procedures and automated/mechanized techniques, the installation process was investigated including the equipment and hardware available, the photovoltaic array structure systems and interfaces, and the array field and site characteristics. Preliminary designs of hardware for both the standard installation method, the automated/mechanized method, and a mix of standard installation procedures and mechanized procedures were identified to determine which process effectively reduced installation costs. In addition, costs associated with each type of installation method and with the design, development and fabrication of new installation hardware were generated.

Global lightning and severe storm monitoring from GPS orbit

DOE Office of Scientific and Technical Information (OSTI.GOV)

Suszcynsky, D. M.; Jacobson, A. R.; Linford, J

Over the last few decades, there has been a growing interest to develop and deploy an automated and continuously operating satellite-based global lightning mapper [e.g. Christian et al., 1989; Weber et al., 1998; Suszcynsky et al., 2000]. Lightning is a direct consequence of the electrification and breakdown processes that take place during the convective stages of thunderstorm development. Satellite-based lightning mappers are designed to exploit this relationship by using lightning detection as a proxy for remotely identifying, locating and characterizing strong convective activity on a global basis. Global lightning and convection mapping promises to provide users with (1) an enhancedmore » global severe weather monitoring and early warning capability [e.g. Weber et al., 1998] (2) improved ability to optimize aviation flight paths around convective cells, particularly over oceanic and remote regions that are not sufficiently serviced by existing weather radar [e.g. Weber et al., 1998], and (3) access to regional and global proxy data sets that can be used for scientific studies and as input into meteorological forecast and global climatology models. The physical foundation for satellite-based remote sensing of convection by way of lightning detection is provided by the basic interplay between the electrical and convective states of a thundercloud. It is widely believed that convection is a driving mechanism behind the hydrometeor charging and transport that produces charge separation and lightning discharges within thunderclouds [e.g. see chapter 3 in MacGorman and Rust, 1998]. Although cloud electrification and discharge processes are a complex function of the convective dynamics and microphysics of the cloud, the fundamental relationship between convection and electrification is easy to observe. For example, studies have shown that the strength of the convective process within a thundercell can be loosely parameterized (with large variance) by the intensity of the electrical activity within that cell as measured by the lightning flash rate. Williams [2001] has provided a review of experimental work that shows correlations between the total lightning flash rate and the fifth power of the radar cloud-top height (i.e. convective strength) of individual thunder cells. More recently, Ushio et al., [2001] used a large statistical sampling of optical data from the Lightning Imaging Sensor (LIS) in conjunction with data provided by the Precipitation Radar (PR) aboard the Tropical Rainfall Monitoring Mission (TRMM) satellite to conclude that the total lightning flash rate increases exponentially with storm height. Lightning activity levels have also been correlated to cloud ice content, a basic product of the convective process. For example, Blyth et al. [2001] used the Thermal Microwave Imager (TMI) aboard the TRMM satellite to observe a decrease in the 37 and 85 GHz brightness temperatures of upwelling terrestrial radiation during increased lightning activity. This reduction in brightness temperature is believed to be the result of increased ice scattering in the mixed phase region of the cloud. Toracinta and Zipser [2001] have found similar relationships using the Optical Transient Detector (OTD) satellite instrument and the Special Sensor Microwave Imager (SSM/I) aboard the DMSP satellites.« less

Rainy Weather Science.

ERIC Educational Resources Information Center

Reynolds, Karen

1996-01-01

Presents ideas on the use of rainy weather for activities in the earth, life, and physical sciences. Topics include formation and collision of raindrops, amount and distribution of rain, shedding of water by plants, mapping puddles and potholes, rainbow formation, stalking storms online, lightning, and comparing particles in the air before and…

Utilizing Yagi antennas in Lightning Mapping Array to detect low-power VHF signals

NASA Astrophysics Data System (ADS)

Tilles, J.; Thomas, R. J.; Edens, H. E.; Krehbiel, P. R.; Rison, W.

2013-12-01

The New Mexico Tech VHF Lightning Mapping Array (LMA) being operated at Langmuir Laboratory in central New Mexico is comprised of 22 time-of-arrival stations spanning an area approximately 60 km north-south and 45 km east-west. Nine stations are at high altitude (3.1-3.3 km GPS) over a 3 x 4 km area around the mountain-top Laboratory, and 13 are on the surrounding plains and the Rio Grande valley, at altitudes between 1.4 and 2.2 km. Each station utilizes a vertical half-wave dipole antenna having about 2 dBi gain at horizontal incidence and providing omnidirectional azimuthal coverage. In 2012, four additional stations utilizing higher gain (11 dBi) Yagi antennas were co-located at four of the surrounding sites within 10-15 km of the laboratory, each pointed over the laboratory area. The purpose was to test if directional antennas would improve detection of low-power sources in the laboratory vicinity, such as those associated with positive breakdown or weak precursor events. The test involved comparing the number and quality of radiation sources obtained by processing data from two sets of stations: first for a 17-station network in which all stations were omnidirectional, and then for the same network with Yagi-based measurements substituted in place of the omni measurements at the four co-located stations. For radiation events located in both datasets, the indicated source power values from Yagi stations were typically 5-10 dB greater than their omnidirectional counterpart for sources over or near the laboratory, consistent with the 9 dB difference in on-axis gain values. The difference decreased through zero and to negative values with increasing distance from the laboratory, confirming that it was due to the directionality of the Yagi antennas. It was expected that a network having Yagi antennas at all outlying stations would improve the network's detection of lower power sources in its central region. Rather, preliminary results show that there is no significant difference in the number of located sources, and that there is no significant difference in flash structure details for either positive or negative breakdown channels. This may be due to a need for more outlying Yagi stations, but could also be the case if in fact the close, high altitude stations are primarily responsible for detection of low power sources, i.e. detection of low power sources does not require or does not benefit much from outlying stations. Furthermore, the ability to detect low power sources may be fundamentally limited due to masking by strongly radiating negative breakdown. Work is continuing on analyzing the measurements.

The Use of EPI-Splines to Model Empirical Semivariograms for Optimal Spatial Estimation

DTIC Science & Technology

2016-09-01

proliferation of unmanned systems in military and civilian sectors has occurred at lightning speed. In the case of Autonomous Underwater Vehicles or...SLAM is a method of position estimation that relies on map data [3]. In this process, the creation of the map occurs as the vehicle is navigating the...that ensures minimal errors. This technique is accomplished in two steps. The first step is creation of the semivariogram. The semivariogram is a

Long duration gamma-ray emission from thunderclouds

NASA Astrophysics Data System (ADS)

Kelley, Nicole A.

Gamma-ray glows are long duration emission coming from thunderclouds. They are one example of high-energy atmospheric physics, a relatively new field studying high-energy phenomena from thunderstorms and lightning. Glows arise from sustained relativistic runaway electron avalanches (RREA). Gamma-ray instruments on the ground, balloons and airplanes have detected glows. The Airborne Detector for Energetic Lightning Emissions (ADELE) is an array of gamma-ray detectors, built at the University of California, Santa Cruz. ADELE detected 12 gamma-ray glows during its summer 2009 campaign. ADELE was designed to study another type of high-energy atmospheric physics, terrestrial gamma-ray flashes (TGFs). TGFs are incredibly bright, sub-millisecond bursts of gamma-rays coming from thunderstorms. ADELE was installed on NCAR's Gulfstream V for the summer of 2009. While many glows were detected, only one TGF was observed. In this thesis I present a detailed explanation of the 2009 version of ADELE along with the results of the 2009 campaign. ADELE was modified to become a smaller, autonomous instrument to fly on the NASA drone, a Global Hawk. This was a piggyback to NASA's Hurricane and Severe Storm Sentinel mission. These flights took place during the summer of 2013. The following summer, ADELE flew on an Orion P3 as a piggyback of NOAA's Hurricane Hunters. This newer, modified instrument is discussed in detail in this thesis. The 12 gamma-ray glows from the 2009 campaign are presented, with information about nearby lightning activity. I show that lightning activity is suppressed after a glow. This could be from the glow causing the cloud to discharge and therefore reduce the lightning activity. It is also possible that glows can only occur once lightning activity has diminished. Lightning is also used to find a distance to the glow. Using this distance, it is found that the brightness of glow cannot be explained as a function of distance while the duration of the glow is related to the distance. The glow measured on August 21, 2009 was 20 times brighter than any other glow. This glow was modeled most extensively and it was found that ADELE was in the end of a downward facing avalanche, implying that is was lying between the upper positive and negative screening layer of the thunderstorm. The brightness of this glow also showed that the avalanche was approaching the levels necessary for relativistic feedback. I also show that this glow provides a significant discharge current and for a short while is discharging the cloud as much as nearby lightning.

Space transportation system flight 2 OSTA-1 scientific payload data management plan

NASA Technical Reports Server (NTRS)

1981-01-01

The Shuttle Imaging Radar-A (SIR-A), Shuttle Multispectral Infrared Radiometer (SMIRR), Future Identification and Location Experiment (FILE), Measurement of Air Pollution from Satellites (MAPS), Ocean Color Experiment (OCE), the Night/Day Optical Survey of Lightning (NOSL), and the Heflex Bioengineering Test (HBT) experiments are described.

System and method for generating a deselect mapping for a focal plane array

DOEpatents

Bixler, Jay V; Brandt, Timothy G; Conger, James L; Lawson, Janice K

2013-05-21

A method for generating a deselect mapping for a focal plane array according to one embodiment includes gathering a data set for a focal plane array when exposed to light or radiation from a first known target; analyzing the data set for determining which pixels or subpixels of the focal plane array to add to a deselect mapping; adding the pixels or subpixels to the deselect mapping based on the analysis; and storing the deselect mapping. A method for gathering data using a focal plane array according to another embodiment includes deselecting pixels or subpixels based on a deselect mapping; gathering a data set using pixels or subpixels in a focal plane array that are not deselected upon exposure thereof to light or radiation from a target of interest; and outputting the data set.

Applied Meteorology Unit (AMU)

NASA Technical Reports Server (NTRS)

Bauman, William; Lambert, Winifred; Case, Jonathan; Short, David; Barrett, Joe

2006-01-01

Develop climatologies of gridded CG lightning densities and frequencies of occurrence for the Melbourne, FL National Weather Service (NWS MLB) county warning area. These grids are used to create a first-guess field for the lightning threat index map that is available on the NWS MLB NASA KSCIKT website. Forecasters previously created this map from scratch. Having the climatologies as a background field will increase consistency between forecasters and decrease their workload. Delivered all files containing the lightning climatologies, the data, and the code used to create the climatologies to NWS MLB. Completed and distributed a final memorandum describing how the climatologies were created. All the files were installed on the NWS MLB computer system, and then the code was compiled and tested to ensure that it worked properly on their operating system. The climatologies and their descriptions are posted on the NWS MLB website. Forecasting Low-Level Convergent Bands Under Southeast Flow Provide guidance to operational personnel that will help improve their forecasts of cloud bands under large-scale southeast flow. When these bands occur, they can lead to cloud, rain, and thunderstorm occurrences that adversely affect launch, landing, and ground operations at Kennedy Space Center/Cape Canaveral Air Force Station (KSC/CCAFS). Completed the first draft of the final report. The conclusions from this task indicated low-level wind speed and direction, low-level high pressure ridge position, east coast sea breeze front activity and upper-level jet streak position have the greatest influence on convergent band formation and movement during southeasterly flow.

Early prediction of eruption site using lightning location data: An operational real-time system in Iceland

NASA Astrophysics Data System (ADS)

Arason, Þórður; Bjornsson, Halldór; Nína Petersen, Guðrún

2013-04-01

Eruption of subglacial volcanoes may lead to catastrophic floods and thus early determination of the exact eruption site may be critical to civil protection evacuation plans. A system is being developed that automatically monitors and analyses volcanic lightning in Iceland. The system predicts the eruption site location from mean lightning locations, taking into account upper level wind. In estimating mean lightning locations, outliers are automatically omitted. A simple wind correction is performed based on the vector wind at the 500 hPa pressure level in the latest radiosonde from Keflavík airport. The system automatically creates a web page with maps and tables showing individual lightning locations and mean locations with and without wind corrections along with estimates of uncetainty. A dormant automatic monitoring system, waiting for a rare event, potentially for several years, is quite susceptible to degeneration during the waiting period, e.g. due to computer or other IT-system upgrades. However, ordinary weather thunderstorms in Iceland should initiate special monitoring and automatic analysis of this system in the same fashion as during a volcanic eruption. Such ordinary weather thunderstorm events will be used to observe anomalies and malfunctions in the system. The essential elements of this system will be described. An example is presented of how the system would have worked during the first hours of the Grímsvötn 2011 eruption. In that case the exact eruption site, within the Grímsvötn caldera, was first known about 15 hours into the eruption.

The protection of photovoltaic power systems from lightning

NASA Astrophysics Data System (ADS)

Rogers, C. B.

Lightning protection techniques at nine prototype photovoltaic power system sites with outputs from 18-225 kW are described. Noting that protection schemes are devised to fit isokeraunic data for specific sites, grounding is cited as a common feature for all systems. The grounds are, in separate instances, connected to junction boxes, frames of the solar cell panels, lead from the dc center, from the dc negative terminal, from the frames and equipment, at the array turntable, or from the building rebar frames. The dc power cables are protected by either metal conduit, metal conduit ground wire, direct burial, by rigid metal conduit, ground conductors, or by ground conductors at the ends of the conduit run. Costs run from 0.01-0.28$/W, with all the systems outfitted with bypass and blocking diodes. Direct stroke protection is viewed as less important than isokeraunic data.

Classification of Small Negative Lightning Reports at the KSC-ER

NASA Technical Reports Server (NTRS)

Ward, Jennifer G.; Cummins, Kenneth L.; Krider, Philip

2008-01-01

The NASA Kennedy Space Center (KSC) and Air Force Eastern Range (ER) operate an extensive suite of lightning sensors because Florida experiences the highest area density of ground strikes in the United States, with area densities approaching 16 fl/sq km/yr when accumulated in 10x10 km (100 sq km) grids. The KSC-ER use data derived from two cloud-to-ground (CG) lightning detection networks, the "Cloud-to-Ground Lightning Surveillance System" (CGLSS) and the U.S. National Lightning Detection Network (TradeMark) (NLDN) plus a 3-dimensional lightning mapping system, the Lightning Detection and Ranging (LDAR) system, to provide warnings for ground operations and to insure mission safety during space launches. For operational applications at the KSC-ER it is important to understand the performance of each lightning detection system in considerable detail. In this work we examine a specific subset of the CGLSS stroke reports that have low values of the negative inferred peak current, Ip, i.e. values between 0 and -7 kA, and were thought to produce a new ground contact (NGC). When possible, the NLDN and LDAR systems were used to validate the CGLSS classification and to determine how many of these reported strokes were first strokes, subsequent strokes in a pre-existing channel (PEC), or cloud pulses that the CGLSS misclassified as CG strokes. It is scientifically important to determine the smallest current that can reach the ground either in the form of a first stroke or by way of a subsequent stroke that creates a new ground contact. In Biagi et al (2007), 52 low amplitude, negative return strokes ([Ip] < or = 10 kA) were evaluated in southern Arizona, northern Texas, and southern Oklahoma. The authors found that 50-87% of the small NLDN reports could be classified as CG (either first or subsequent strokes) on the basis of video and waveform recordings. Low amplitude return strokes are interesting because they are usually difficult to detect, and they are thought to bypass conventional lightning protection that relies on a sufficient attractive radius to prevent "shielding failure" (Golde, 1977). They also have larger location errors compared to the larger current events. In this study, we use the estimated peak current provided by the CGLSS and the results of our classification to determine the minimum Ip for each category of CG stroke and its probability of occurrence. Where possible, these results are compared to the findings in the literature.

Towards understanding the nature of any relationship between Solar Activity and Cosmic Rays with thunderstorm activity and lightning discharge

NASA Astrophysics Data System (ADS)

O'Regan, J.; Muller, J.-P.; Matthews, S.

2012-04-01

The runaway breakdown hypothesis of lightning discharge has predicted relationships between cosmic rays' interactions with the atmosphere and thunderstorm production and lightning activity. Precipitating energetic particles lead to the injection of MeV-energy electrons into electrified thunderclouds [1,2], resulting in runaway breakdown occurring, and assisting in the process of charge separation [2]. Previous lightning studies show that correlations to solar activity are weak but significant, with better correlations to solar activity and cosmic rays when carried out over smaller geographical areas [3,4,5,6] and over longer timescales [6]. In this work, correlations are explored between variations of SEPs and lightning activity levels at various spatio-temporal scales. Temporal scales span from short-term (days) scales surrounding large Earth-directed coronal mass ejection (CME) events to long-term (years) scales. Similarly, spatial scales span from 1-degree x 1-degree latitudinal-longitudinal grid scales to an entirely global study, for varying timescales. Additionally, investigation of correlation sign and statistical significance by 1-degree latitudinal bands is also employed, allowing a comparative study of lightning activity relative to regions of greatest - and contrasting regions of relative absence of - energetic particle precipitation. These regions are determined from electron and proton flux maps, derived from measurements from the Medium Energy Proton and Electron Detector (MEPED) onboard the Polar Orbiting Environmental Satellite (POES) system. Lightning data is obtained from the World Wide Lightning Location Network (WWLLN) for the period 2005 to 2011. The correlations of lightning strike rates are carried out with respect to Relative Sunspot Number (R), 10.7cm Solar radio flux (F10.7), Galactic Cosmic Ray (GCR) neutron monitor flux, the Ap geomagnetic activity index, and Disturbance Storm Time (DST) index. Correlations show dramatic variations in both sign and significance over small geographic distances, similar to previous results [3,4,6], highlighting the complexity of the atmospheric processes contributing to the mechanism of thunderstorm generation and lightning discharge. We find correlations are generally more significant over larger timescales, as daily meteorological variability is smoothened out, suggesting a role for changing Solar activity levels in influencing thunderstorm development and onset of lightning discharge. Comparisons of small-scale correlation results to planetary wave patterns suggests an influence over the correlations of lightning activity to the above indices, as proposed by Schlegel et al. [6], and previously suggested by the results of Fritz [3] and Brooks [4]. Our results show agreement with Schlegel et al. [6] for the same region over Germany, but are in disagreement with their results for Austria. This lends support to the idea of the theory of planetary waves influence over correlation signs and significance across short geographic distances, as discussed by Schlegel et al. [6]. Acknowledgement: The authors wish to thank the World Wide Lightning Location Network (http://wwlln.net), a collaboration among over 50 universities and institutions (including MSSL) for providing the lightning location data used in this paper. [1] Ermakov, V.I. and Stozhkov, Yu.I., 2003. Cosmic rays in the mechanism of thundercloud production. 28th International Cosmic Ray Conference, pp. 4157-4160. [2] Kirkby, J., 2007. Cosmic rays and climate. Surv Geophys, vol. 28 (5-6) pp. 333-375. [3] Fritz, H., 1878. Die wichtigsten periodischen Erscheinungen der Meteorologie und Kosmologie. Natuurkundige Verhandelingen van de Hollandsche Maatschappij der Wetenschappen te Haarlem, Deel III, Haarlem. [4] Brooks, C.E.P., 1934. The variation of the annual frequency of thunderstorms in relation to sunspots. Quarterly Journal of the Royal Meteorological Society 60, 153-165. [5] Stringfellow, M.F., 1974. Lightning incidence in Britain and the solar cycle. Nature 249, 332-333. [6] Schlegel, K. et al, 2001. Thunderstorms, lightning and solar activity - Middle Europe. J Atmos Sol-Terr Phy vol. 63 (16) pp. 1705-1713

A simultaneous multichannel monophasic action potential electrode array for in vivo epicardial repolarization mapping.

PubMed

Sahakian, A V; Peterson, M S; Shkurovich, S; Hamer, M; Votapka, T; Ji, T; Swiryn, S

2001-03-01

While the recording of extracellular monophasic action potentials (MAPs) from single epicardial or endocardial sites has been performed for over a century, we are unaware of any previous successful attempt to record MAPs simultaneously from a large number of sites in vivo. We report here the design and validation of an array of MAP electrodes which records both depolarization and repolarization simultaneously at up to 16 epicardial sites in a square array on the heart in vivo. The array consists of 16 sintered Ag-AgCl electrodes mounted in a common housing with individual suspensions allowing each electrode to exert a controlled pressure on the epicardial surface. The electrodes are arranged in a square array, with each quadrant of four having an additional recessed sintered Ag-AgCl reference electrode at its center. A saline-soaked sponge establishes ionic contact between the reference electrodes and the tissue. The array was tested on six anesthetized open-chested pigs. Simultaneous diagnostic-quality MAP recordings were obtained from up to 13 out of 16 ventricular sites. Ventricular MAPs had amplitudes of 10-40 mV with uniform morphologies and stable baselines for up to 30 min. MAP duration at 90% repolarization was measured and shown to vary as expected with cycle length during sustained pacing. The relationship between MAP duration and effective refractory period was also confirmed. The ability of the array to detect local differences in repolarization was tested in two ways. Placement of the array straddling the atrioventricular (AV) junction yielded simultaneous atrial or ventricular recordings at corresponding sites during 1:1 and 2:1 AV conduction. Localized ischemia via constriction of a coronary artery branch resulted in shortening of the repolarization phase at the ischemic, but not the nonischemic, sites. In conclusion, these results indicate that the simultaneous multichannel MAP electrode array is a viable method for in vivo epicardial repolarization mapping. The array has the potential to be expanded to increase the number of sites and spatial resolution.

Preliminary Optical And Electric Field Pulse Statistics From Storm Overflights During The Altus Cumulus Electrification Study

NASA Technical Reports Server (NTRS)

Mach, D. A.; Blakeslee, R. J.; Bailey, J. C.; Farrell, W. M.; Goldberg, R. A.; Desch, M. D.; Houser, J. G.

2003-01-01

The Altus Cumulus Electrification Study (ACES) was conducted during the month of August, 2002 in an area near Key West, Florida. One of the goals of this uninhabited aerial vehicle (UAV) study was to collect high resolution optical pulse and electric field data from thunderstorms. During the month long campaign, we acquired 5294 lightning generated optical pulses with associated electric field changes. Most of these observations were made while close to the top of the storms. We found filtered mean and median 10-10% optical pulse widths of 875 and 830 microns respectively while the 50-50% mean and median optical pulse widths are 422 and 365 microns respectively. These values are similar to previous results as are the 10-90% mean and median rise times of 327 and 265 microns. The peak electrical to optical pulse delay mean and median were 209 and 145 microns which is longer than one would expect from theoretical results. The results of the pulse analysis will contribute to further validation of the Optical Transient Detector (OTD) and the Lightning Imaging Sensor (LIS) satellites. Pre-launch estimates of the flash detection efficiency were based on a small sample of optical pulse measurements associated with less than 350 lightning discharges collected by NASA U-2 aircraft in the early 1980s. Preliminary analyses of the ACES measurements show that we have greatly increased the number of optical pulses available for validation of the LIS and other orbital lightning optical sensors. Since the Altus was often close to the cloud tops, many of the optical pulses are from low-energy pulses. From these low-energy pulses, we can determine the fraction of optical lightning pulses below the thresholds of LIS, OTD, and any future satellite-based optical sensors such as the geostationary Lightning Mapping Sensor.

Small Winter Thunderstorm with Sprites and Strong Positive Discharge

NASA Astrophysics Data System (ADS)

Suzuki, Tomoyuki; Hayakawa, Masashi; Michimoto, Koichiro

A sprite campaign was conducted in the Hokuriku area of Japan during a winter of 2004/2005. On the basis of a combined analysis of the data from various instruments (CCD cameras, radar, VHF/LF∼MF lightning mapping system, field mill network, and ELF detector), we studied meteorological and electrical structures for winter thunderstorms and sprite-producing positive discharge. Typical winter sprite parent thunderstorms had a meso-scale cloud area with embedded small convective cells. Some small winter thunderstorms accompanied by the most frequent sprite events were found to cause 2∼3 sprite events during a short interval of about 3∼5 min. When the sprites were observed, the extent of the convective cells at 20 dBZ counter was atmost ∼20 × 20 km. The VHF sources associated with sprites were located near south of the convective cell and were mapped within very small areas of at most ∼10 × 10 km. This fact shows that some small winter thunderstorms can generate large positive charge associated with sprites. We will present the analysis of such a small thunderstorms with sprites and positive lightning discharges.

Temporal and spatial structure in a daily wildfire-start data set from the western United States (198696)

USGS Publications Warehouse

Bartlein, P.J.; Hostetler, S.W.; Shafer, S.L.; Holman, J.O.; Solomon, A.M.

2008-01-01

The temporal and spatial structure of 332 404 daily fire-start records from the western United States for the period 1986 through 1996 is illustrated using several complimentary visualisation techniques. We supplement maps and time series plots with Hovmo??ller diagrams that reduce the spatial dimensionality of the daily data in order to reveal the underlying space?time structure. The mapped distributions of all lightning- and human-started fires during the 11-year interval show similar first-order patterns that reflect the broad-scale distribution of vegetation across the West and the annual cycle of climate. Lightning-started fires are concentrated in the summer half-year and occur in widespread outbreaks that last a few days and reflect coherent weather-related controls. In contrast, fires started by humans occur throughout the year and tend to be concentrated in regions surrounding large-population centres or intensive-agricultural areas. Although the primary controls of human-started fires are their location relative to burnable fuel and the level of human activity, spatially coherent, weather-related variations in their incidence can also be noted. ?? IAWF 2008.

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

NASA Astrophysics Data System (ADS)

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

2017-12-01

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

Characterizing charge centroids from lightning using a slow antenna network and the Levenberg-Marquardt inverse method

NASA Astrophysics Data System (ADS)

Lapierre, J. L.; Sonnenfeld, R. G.; Hager, W. W.; Morris, K.

2011-12-01

Researchers have long studied the copious and complex electric field waveforms caused by lightning. By combining electric-field measurements taken at many different locations on the ground simultaneously [Krehbiel et al., 1979], we hope to learn more about charge sources for lightning flashes. The Langmuir Electric Field Array (LEFA) is a network of nine field-change measurement stations (slow-antennas) arranged around Langmuir Laboratory near Magdalena, New Mexico. Using a mathematical method called the Levenberg-Marquardt (LM) method, we can invert the electric field data to determine the magnitude and position of the charge centroid removed from the cloud. We analyzed three return strokes (RS) following a dart-leader from a storm occurring on October 21st 2011. RS 'A' occurred at 07:17:00.63 UT. The altitude of the charge centroid was estimated to be 5 km via LMA data. Because the LM method requires a prediction, the code was run with a wide range of values to verify the robustness of the method. Predictions varied from ±3 C for the charge magnitude and ±20 km N-S and E-W for the position (with the coordinate origin being the Langmuir Laboratory Annex). The LM method converged to a charge magnitude of -5.5 C and a centroid position of 3.3 km E-W and 12 km, N-S for that RS. RS 'B' occurred at 07:20:05.9 UT. With an altitude of 4 km, the predictions were again varied; ±3 C, ±15 km N-S and E-W. Most runs converged to -27.5 C, 4 km E-W, and 10.9 km N-S. Finally, while results seem best for events right over the array, success was had locating more distant events. RS 'C' occurred at 02:42:46.8 UT. Assuming an altitude of 5 km and varying the predictions as with RS 'A', the results converged to -9.2 C, 35.5 km E-W, and 9 km N-S. All of these results are broadly consistent with the LMA and the NLDN. By continuing this type of analysis, we hope to learn more about how lightning channels propagate and how the charges in the cloud respond to the sudden change in charge distribution after a CG flash. Reference Krehbiel, P.R., M. Brook, and R. A. McCrory (1979), An analysis of the charge structure of lightning discharges to ground, J. Geophys. Res., 84(C5), 2432-2456. We gratefully acknowledge support from the National Science Foundation Grant No. 0724771.

Lightning and Other Influences On Tropical Tropospheric Ozone: Empirical Studies of Covariation

NASA Technical Reports Server (NTRS)

Chatfield, Robert B.; Guan, Hong; Hudson, Robert D.; Witte, Jacquelyne C.

2003-01-01

Tropical and subtropical tropospheric ozone are important radiatively active species, with particularly large effects in the upper third of the troposphere. Temporal variability of O3 has proved difficult to simulate day by day in process models. Thus, individual roles of lightning, biomass burning, and other pollution in providing precursor NO(x), radicals, and chain carriers (CO, hydrocarbons) remain unquantified by simulation, and it is theoretically reasonable that individual roles are magnified by a joint synergy. We use wavelet analysis and Burg-algorithm maximum entropy spectral analyses to describe time-scales and correlation of ozone with proxies for processes controlling its concentration. Our empirical studies link time variations apparent in several datasets: the SHADOZ (Southern Hemisphere Additional Ozonesondes) network stations (Nairobi, Fiji), and auxiliary series with power to explain ozone-determining processes, with some interpretation based on the TTO (Tropical Tropospheric Ozone) product derived from TOMS (the Total Ozone Mapping Spectrometer). The auxiliary series are The OTD/LIS(Optical Transient Detector/Lightning Imaging Sensor) measurements of the lightning NO(x) source, the OLR (Outgoing Longwave Radiation)measurement of high-topped clouds, and standard meteorological variables from the United States NCEP (National Centers for Environmental Prediction) and Data Assimilation Office analyses. Concentrating on equatorial ozone, we compare the statistical evidence on the variability of tropospheric ozone. Important variations occur on approximately two-week, two-month (Madden-Julian Oscillation) and annual scales, and relations with OLR suggest controls associated with continental clouds. Hence we are now using the Lightning Imaging Sensor data set to indicate NO(x) sources. We report initial results defining relative roles of the process mentioned affecting O3 using their covariance properties.

Volcanic Lightning, Pyroclastic Density Currents, Ballistic Fall, Vent Tremor, and One Very Loud Blast: Acoustic Analysis of the 14 July 2013 Vulcanian Eruption at Tungurahua, Ecuador.

NASA Astrophysics Data System (ADS)

Anderson, J.; Johnson, J. B.; Steele, A. L.; Anzieta, J. C.; Ortiz, H. D.; Hall, M. L.; Ruiz, M. C.

2014-12-01

Acoustic recordings reveal a variety of volcanic activities during an exceptionally loud vulcanian eruption at Tungurahua. A period of several months of mild surface activity came to an abrupt end with the emission of a powerful blast wave heard at least 180 km away. Sensors 2080 m from the vent recorded a stepped rise to its maximum overpressure of 1220 Pa (corresponding to a sound pressure level of 156 dB) and its unusually long dominant period of 5.6 s. We discuss source processes that produced the blast wave, considering that wave propagation could be nonlinear near the vent because of high overpressures. More than an hour of acoustic activity was recorded after the blast wave, including sound from falling ballistics, reflections of the blast wave from nearby mountains, pyroclastic density currents, and acoustic tremor at the vent. Glitches in the acoustic records related to plume lightning were also serendipitously observed, although thunder could not be unambiguously identified. We discuss acoustic signatures of falling ballistics and pyroclastic density currents and how array-style deployments and analytic methods can be used to reveal them. Placement of sensors high on the volcano's slopes facilitated resolving these distinct processes. This study demonstrates that near-vent, array-style acoustic installations can be used to monitor various types of volcanic activity.

Science of Ball Lightning (Fire Ball)

NASA Astrophysics Data System (ADS)

Ohtsuki, Yoshi-Hiko

1989-08-01

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

Determination and representation of electric charge distributions associated with adverse weather conditions

NASA Technical Reports Server (NTRS)

Rompala, John T.

1992-01-01

Algorithms are presented for determining the size and location of electric charges which model storm systems and lightning strikes. The analysis utilizes readings from a grid of ground level field mills and geometric constraints on parameters to arrive at a representative set of charges. This set is used to generate three dimensional graphical depictions of the set as well as contour maps of the ground level electrical environment over the grid. The composite, analytic and graphic package is demonstrated and evaluated using controlled input data and archived data from a storm system. The results demonstrate the packages utility as: an operational tool in appraising adverse weather conditions; a research tool in studies of topics such as storm structure, storm dynamics, and lightning; and a tool in designing and evaluating grid systems.

Lightning impact on micro-second long ionospheric variability

NASA Astrophysics Data System (ADS)

Koh, Kuang Liang; Liu, Zhongjian; Fullekrug, Martin

2017-04-01

Lightning discharges cause electron heating and enhanced ionisation in the D region ionosphere which disturb the transmission of VLF communications [Inan et al., 2010]. A disturbance of such nature was measured in a VLF transmission with a sampling rate of 1 MHz, enabling much faster ionospheric variability to be observed when compared to previous studies which typically report results with a time resolution >5-20ms. The disturbance resembles "Long Recovery Early VLF" (LORE) events [Haldoupis et al. 2013, Cotts & Inan 2007]. LOREs exhibit observable ionospheric effects that last longer (>200s) than other lightning related disturbances. It was proposed that the mechanism behind the long-lasting effects of LOREs is different to shorter events [Gordillo-Vázquez et al. 2016]. The ionospheric variability inferred from the transmitted signal is seen to change dramatically after the lightning onset, suggesting that there are fast processes in the ionosphere affected or produced which have not been considered in previous research. The ionospheric variability inferred from the main two frequencies of the transmission is different. A possible explanation is a difference in the propagation paths of the two main frequencies of the transmission [Füllekrug et al., 2015]. References Inan, U.S., Cummer, S.A., Marshall, R.A., 2010. A survey of ELF and VLF research on lightning-ionosphere interactions and causative discharges. J. Geophys. Res. 115, A00E36. doi:10.1029/2009JA014775 Cotts, B.R.T., Inan, U.S., 2007. VLF observation of long ionospheric recovery events. Geophys. Res. Lett. 34, L14809. doi:10.1029/2007GL030094 Haldoupis, C., Cohen, M., Arnone, E., Cotts, B., Dietrich, S., 2013. The VLF fingerprint of elves: Step-like and long-recovery early VLF perturbations caused by powerful ±CG lightning EM pulses. J. Geophys. Res. Space Physics 118, 5392-5402. doi:10.1002/jgra.50489 Gordillo-Vázquez, F.J., Luque, A., Haldoupis, C., 2016. Upper D region chemical kinetic modeling of LORE relaxation times: KINETIC MODEL OF LORE RELAXATION TIMES. Journal of Geophysical Research: Space Physics 121, 3525-3544. doi:10.1002/2015JA021408 Füllekrug, M., Smith, N., Mezentsev, A., Watson, R., Astin, I., Gaffet, S., Evans, A., Rycroft, M., 2015. Multipath propagation of low-frequency radio waves inferred from high-resolution array analysis. Radio Sci. 50, 2015RS005781. doi:10.1002/2015RS005781

Lightning Mapping Observations of Volume-Filling Small Discharges in Thunderstorms

NASA Astrophysics Data System (ADS)

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

2013-12-01

Lightning is usually considered to be a large-scale electrical discharge in the atmosphere. For example, the American Meteorological Society's Glossary of Meteorology defines lightning as "a transient, high-current electric discharge with pathlengths measured in kilometers" (http://glossary.ametsoc.org/wiki/Lightning). There have been several reported examples of short-duration discharges in thunderstorms, which have a duration of a few microseconds to less than a millisecond, and have a small spatial extent These short-duration discharges were located at high altitudes (> 14 km), altitudes consistent with being located between the upper positive charge and the negative screening layer. At these altitudes, the electric field needed to initiate an electrical discharge is much lower than it is at the altitudes of initiation for IC (~8 km) or CG (~5 km) flashes. We have recently reported on short-duration "precursor" discharges with durations of a few microseconds to a few milliseconds, which occur in the high-fields between the mid-level negative and upper positive charge regions. These "precursor" discharges are discrete in both time and space, being separated in time by hundreds of milliseconds to several seconds, and localized in space, usually very close to the initiation location of a subsequent IC discharge. We have recently observed nearly continuous, volume filling short-duration discharges in several thunderstorms. These discharges have durations of much less than a millisecond, spatial extents of less than a few hundred meters, and occur randomly in the volume between the mid-level negative and upper positive charge regions. During an active period, these discharges occur every few milliseconds. The rates of these discharges decreases dramatically to a few per second following an IC discharge, then increases to several hundred per second until the next discharge. In a storm just off the Florida coast, one cell was producing a large number of these small discharges, while a contemporaneous cell a few kilometers west produced no detectable small discharges. Short-duration discharges occur at altitudes between 10 km and 14 km in the intervals between lightning discharges. The rates of short-duration discharges decreases dramatically after a lightning discharge.

Venus Express Contributions to the Study of Planetary Lightning

NASA Astrophysics Data System (ADS)

Russell, C. T.; Hart, R. A.; Zhang, T. L.

2014-04-01

Jupiter, and Saturn are expected to generate the electrical potential differences in their clouds sufficient to cause a breakdown in the atmosphere,creating a conducting path for the electric potential to discharge. This high-energy phenomenon creates a hot, high-pressure channel that enables chemical reactions not possible under usual local thermodynamic conditions. Thus it is of some interest to determine if lightning occurs in an atmosphere. While Venus is not usually considered one of the wet planets, lightning has been an object of interest since the Venera landers. It was observed with electromagnetic coils on Venera 11, 12, 13, 14 landers [2]. It was observed with a visible spectrometer on the Venera 9 orbits [1]. It was mapped during solar occultations by the electric antenna on the Pioneer Venus Orbiter [4]. These measurements revealed extensive lightning activity with an electromagnetic energy flux similar to that on Earth. However, the observations were limited in number in the atmosphere and to the nightside from orbit. In order to improve the understanding of Venus lightning, the Venus Express magnetometer was given a 128-Hz sampling rate that could cover much of the ELF frequencies at which lightning could be observed in the weak magnetic fields of the Venus ionosphere [5]. This investigation was immediately successful [3], but mastering the cleaning of the broadband data took several years to accomplish. Furthermore, the high polar latitudes of VEX periapsis were not the ideal locations to conduct the more global survey that was desired. Fortunately, after precessing poleward over the first few years the latitude of periapsis has returned to lower latitudes(Figures 1 and 2) and active electrical storms are now being studied. The charged constituent of the Venus atmosphere need not be water. In fact, we believe it is H2SO4 which polarizes much as water does and which freezes and melts at similar temperatures. If it is H2SO4, we would expect the constituent to be sensitive to the rate of Venus volcanism releasing sulfur and sulfur dioxide into the atmosphere. This is one correlation we are anxious to pursue on future missions.

Seasonal and Local Characteristics of Lightning Outages of Power Distribution Lines in Hokuriku Area

NASA Astrophysics Data System (ADS)

Sugimoto, Hitoshi; Shimasaki, Katsuhiko

The proportion of the lightning outages in all outages on Japanese 6.6kV distribution lines is high with approximately 20 percent, and then lightning protections are very important for supply reliability of 6.6kV lines. It is effective for the lightning performance to apply countermeasures in order of the area where a large number of the lightning outages occur. Winter lightning occurs in Hokuriku area, therefore it is also important to understand the seasonal characteristics of the lightning outages. In summer 70 percent of the lightning outages on distribution lines in Hokuriku area were due to sparkover, such as power wire breakings and failures of pole-mounted transformers. However, in winter almost half of lightning-damaged equipments were surge arrester failures. The number of the lightning outages per lightning strokes detected by the lightning location system (LLS) in winter was 4.4 times larger than that in summer. The authors have presumed the occurrence of lightning outages from lightning stroke density, 50% value of lightning current and installation rate of lightning protection equipments and overhead ground wire by multiple regression analysis. The presumed results suggest the local difference in the lightning outages.

Modern concepts of treatment and prevention of lightning injuries.

PubMed

Edlich, Richard F; Farinholt, Heidi-Marie A; Winters, Kathryne L; Britt, L D; Long, William B

2005-01-01

Lightning is the second most common cause of weather-related death in the United States. Lightning is a natural atmospheric discharge that occurs between regions of net positive and net negative electric charges. There are several types of lightning, including streak lightning, sheet lightning, ribbon lightning, bead lightning, and ball lightning. Lightning causes injury through five basic mechanisms: direct strike, flash discharge (splash), contact, ground current (step voltage), and blunt trauma. While persons struck by lightning show evidence of multisystem derangement, the most dramatic effects involve the cardiovascular and central nervous systems. Cardiopulmonary arrest is the most common cause of death in lightning victims. Immediate resuscitation of people struck by lightning greatly affects the prognosis. Electrocardiographic changes observed following lightning accidents are probably from primary electric injury or burns of the myocardium without coronary artery occlusion. Lightning induces vasomotor spasm from direct sympathetic stimulation resulting in severe loss of pulses in the extremities. This vasoconstriction may be associated with transient paralysis. Damage to the central nervous system accounts for the second most debilitating group of injuries. Central nervous system injuries from lightning include amnesia and confusion, immediate loss of consciousness, weakness, intracranial injuries, and even brief aphasia. Other organ systems injured by lightning include the eye, ear, gastrointestinal system, skin, and musculoskeletal system. The best treatment of lightning injuries is prevention. The Lightning Safety Guidelines devised by the Lightning Safety Group should be instituted in the United States and other nations to prevent these devastating injuries.

Produce documents and media information. [on lightning

NASA Technical Reports Server (NTRS)

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

1994-01-01

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

Bi-sensory, striped representations: comparative insights from owl and platypus.

PubMed

Pettigrew, John D

2004-01-01

Bi-sensory striped arrays are described in owl and platypus that share some similarities with the other variant of bi-sensory striped array found in primate and carnivore striate cortex: ocular dominance columns. Like ocular dominance columns, the owl and platypus striped systems each involve two different topographic arrays that are cut into parallel stripes, and interdigitated, so that higher-order neurons can integrate across both arrays. Unlike ocular dominance stripes, which have a separate array for each eye, the striped array in the middle third of the owl tectum has a separate array for each cerebral hemisphere. Binocular neurons send outputs from both hemispheres to the striped array where they are segregated into parallel stripes according to hemisphere of origin. In platypus primary somatosensory cortex (S1), the two arrays of interdigitated stripes are derived from separate sensory systems in the bill, 40,000 electroreceptors and 60,000 mechanoreceptors. The stripes in platypus S1 cortex produce bimodal electrosensory-mechanosensory neurons with specificity for the time-of-arrival difference between the two systems. This "thunder-and-lightning" system would allow the platypus to estimate the distance of the prey using time disparities generated at the bill between the earlier electrical wave and the later mechanical wave caused by the motion of benthic prey. The functional significance of parallel, striped arrays is not clear, even for the highly-studied ocular dominance system, but a general strategy is proposed here that is based on the detection of temporal disparities between the two arrays that can be used to estimate distance.

Mapping the African thunderstorm center in absolute units using Schumann resonance spectral decomposition method

NASA Astrophysics Data System (ADS)

Dyrda, Michal; Kulak, Andrzej; Mlynarczyk, Janusz

2015-04-01

Monitoring of the global lightning activity provides a very useful tool to study the global warming phenomenon and the other longer-scale climate changes induced by humans. The lightning activity is measured using various observational methods form space (optical satellite observations) as well as from the ground mostly by VLF /LF lightning detection networks, i.e. World Wide Lightning Location Network (WWLLN) or lightning detection network (LINET) in Europe. However, the global lightning activity measurements are possible only in the ELF range. Here we examine the African thunderstorm activity center, which is the most violent and active one. In a spherical damped resonator, such as the Earth-ionosphere cavity, the electromagnetic field is described by the solution of an inhomogeneous wave equation. For such equation the general solution can be expressed by the superposition of the solutions of the homogeneous equation, describing the resonance field, and the component, which is quite strong close to the source and weakens with source-observer separation. Thus, the superposition of the standing wave field with the field of traveling waves, which supply the energy from the lighting discharges to the global resonator, is a main reason for an asymmetric shape of the observational Schumann resonance (SR) power spectra, which highly deviate from the Lorentz curves. It is possible to separate this component from the signal using the spectrum decomposition method proposed by Kułak et al. [2006]. In our approach, we apply the inverse problem solution for determining the distance of the dominant lightning source. The distances to the thunderstorm centers are calculated using the analytical models for the electromagnetic waves propagation in the Earth-ionosphere cavity. Such forms of analytic solutions of the resonant field in the spherical cavity is the zonal harmonic series representation, described by Mushtak and Williams [2002] and we calculated the sets of such curves for different source-observer separations, starting at 1 Mm up to 20 Mm with a step of 0.1 Mm. We selected two observational data sets, collected during different seasons of the year, from our Hylaty station, located in Poland. The data were binned in 10-minute files for which the SR power spectra were derived. In the next step a decomposition curve describing 7 asymmetric SR modes was fitted to the observational data. To compare the resulted decomposed power spectra with analytic model we use chi-squared test and hence we obtained the distances to the dominant thunderstorm center, located in Africa. We computed the monthly lighting activity maps and possible locations on the African continent with the spatial resolution of 1 degree and temporal resolution of 10 minute. Moreover we calculated the thunderstorm intensities in physical units, which are of the order of 2 × 1011 [C2 m2 s-1]. We also notice the seasonal variations of the African thunderstorm centers distributions and as well as intensities. Finally, we compared our results with satellite data recorded by the Lighting Imaging Sensor (LIS) and we obtained very high correlation. Acknowledgements. This work has been supported by the National Science Centre grant 2012/04/M/ST10/00565. The numerical computations were done using the PL-Grid infrastructure.

A comparison between initial continuous currents of different types of upward lightning

NASA Astrophysics Data System (ADS)

Wang, D.; Sawada, N.; Takagi, N.

2009-12-01

We have observed the lightning to a wind turbine and its lightning-protection tower for four consecutive winter seasons from 2005 to 2009. Our observation items include (1) thunderstorm electrical fields and lightning-caused electric field changes at multi sites around the wind turbine, (2) electrical currents at the bottom of the wind turbine and its lightning protection tower, (3) normal video and high speed image of lightning optical channels. Totally, we have obtained the data for 42 lightning that hit either on wind turbine or its lightning protection tower or both. Among these 42 lightning, 38 are upward lightning and 2 are downward lightning. We found the upward lightning can be sub-classified into two types. Type 1 upward lightning are self-triggered from a high structure, while type 2 lightning are triggered by a discharge occurred in other places which could be either a cloud discharge or a cloud-to-ground discharge (other-triggered). In this study, we have compared the two types of upward lightning in terms of initial continuous current rise time, peak current and charge transferred to the ground. We found that the initial current of self-triggered lightning tends to rise significantly faster and to a bigger peak value than the other-triggered lightning, although both types of lightning transferred similar amount of charge to the ground.

Development of a dense SNP-based linkage map of an apple rootstock progeny using the Malus Infinium whole genome genotyping array.

PubMed

Antanaviciute, Laima; Fernández-Fernández, Felicidad; Jansen, Johannes; Banchi, Elisa; Evans, Katherine M; Viola, Roberto; Velasco, Riccardo; Dunwell, Jim M; Troggio, Michela; Sargent, Daniel J

2012-05-25

A whole-genome genotyping array has previously been developed for Malus using SNP data from 28 Malus genotypes. This array offers the prospect of high throughput genotyping and linkage map development for any given Malus progeny. To test the applicability of the array for mapping in diverse Malus genotypes, we applied the array to the construction of a SNP-based linkage map of an apple rootstock progeny. Of the 7,867 Malus SNP markers on the array, 1,823 (23.2%) were heterozygous in one of the two parents of the progeny, 1,007 (12.8%) were heterozygous in both parental genotypes, whilst just 2.8% of the 921 Pyrus SNPs were heterozygous. A linkage map spanning 1,282.2 cM was produced comprising 2,272 SNP markers, 306 SSR markers and the S-locus. The length of the M432 linkage map was increased by 52.7 cM with the addition of the SNP markers, whilst marker density increased from 3.8 cM/marker to 0.5 cM/marker. Just three regions in excess of 10 cM remain where no markers were mapped. We compared the positions of the mapped SNP markers on the M432 map with their predicted positions on the 'Golden Delicious' genome sequence. A total of 311 markers (13.7% of all mapped markers) mapped to positions that conflicted with their predicted positions on the 'Golden Delicious' pseudo-chromosomes, indicating the presence of paralogous genomic regions or mis-assignments of genome sequence contigs during the assembly and anchoring of the genome sequence. We incorporated data for the 2,272 SNP markers onto the map of the M432 progeny and have presented the most complete and saturated map of the full 17 linkage groups of M. pumila to date. The data were generated rapidly in a high-throughput semi-automated pipeline, permitting significant savings in time and cost over linkage map construction using microsatellites. The application of the array will permit linkage maps to be developed for QTL analyses in a cost-effective manner, and the identification of SNPs that have been assigned erroneous positions on the 'Golden Delicious' reference sequence will assist in the continued improvement of the genome sequence assembly for that variety.

Principles of Lightning Physics

NASA Astrophysics Data System (ADS)

Mazur, Vladislav

2016-12-01

Principles of Lightning Physics presents and discusses the most up-to-date physical concepts that govern many lightning events in nature, including lightning interactions with man-made structures, at a level suitable for researchers, advanced students and well-educated lightning enthusiasts. The author's approach to understanding lightning-to seek out, and show what is common to all lightning flashes-is illustrated by an analysis of each type of lightning and the multitude of lightning-related features. The book examines the work that has gone into the development of new physical concepts, and provides critical evaluations of the existing understanding of the physics of lightning and the lexicon of terms and definitions presently used in lightning research.

Inspection design using 2D phased array, TFM and cueMAP software

DOE Office of Scientific and Technical Information (OSTI.GOV)

McGilp, Ailidh; Dziewierz, Jerzy; Lardner, Tim

2014-02-18

A simulation suite, cueMAP, has been developed to facilitate the design of inspection processes and sparse 2D array configurations. At the core of cueMAP is a Total Focusing Method (TFM) imaging algorithm that enables computer assisted design of ultrasonic inspection scenarios, including the design of bespoke array configurations to match the inspection criteria. This in-house developed TFM code allows for interactive evaluation of image quality indicators of ultrasonic imaging performance when utilizing a 2D phased array working in FMC/TFM mode. The cueMAP software uses a series of TFM images to build a map of resolution, contrast and sensitivity of imagingmore » performance of a simulated reflector, swept across the inspection volume. The software takes into account probe properties, wedge or water standoff, and effects of specimen curvature. In the validation process of this new software package, two 2D arrays have been evaluated on 304n stainless steel samples, typical of the primary circuit in nuclear plants. Thick section samples have been inspected using a 1MHz 2D matrix array. Due to the processing efficiency of the software, the data collected from these array configurations has been used to investigate the influence sub-aperture operation on inspection performance.« less

Mapping Capacitive Coupling Among Pixels in a Sensor Array

NASA Technical Reports Server (NTRS)

Seshadri, Suresh; Cole, David M.; Smith, Roger M.

2010-01-01

An improved method of mapping the capacitive contribution to cross-talk among pixels in an imaging array of sensors (typically, an imaging photodetector array) has been devised for use in calibrating and/or characterizing such an array. The method involves a sequence of resets of subarrays of pixels to specified voltages and measurement of the voltage responses of neighboring non-reset pixels.

Methods of Real Time Image Enhancement of Flash LIDAR Data and Navigating a Vehicle Using Flash LIDAR Data

NASA Technical Reports Server (NTRS)

Vanek, Michael D. (Inventor)

2014-01-01

A method for creating a digital elevation map ("DEM") from frames of flash LIDAR data includes generating a first distance R(sub i) from a first detector i to a first point on a surface S(sub i). After defining a map with a mesh THETA having cells k, a first array S(k), a second array M(k), and a third array D(k) are initialized. The first array corresponds to the surface, the second array corresponds to the elevation map, and the third array D(k) receives an output for the DEM. The surface is projected onto the mesh THETA, so that a second distance R(sub k) from a second point on the mesh THETA to the detector can be found. From this, a height may be calculated, which permits the generation of a digital elevation map. Also, using sequential frames of flash LIDAR data, vehicle control is possible using an offset between successive frames.

A Lightning Safety Primer for Camps.

ERIC Educational Resources Information Center

Attarian, Aram

1992-01-01

Provides the following information about lightning, which is necessary for camp administrators and staff: (1) warning signs of lightning; (2) dangers of lightning; (3) types of lightning injuries; (4) prevention of lightning injury; and (5) helpful training tips. (KS)

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

NASA Astrophysics Data System (ADS)

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

2006-12-01

The results of the 2005-6 winter sprite campaign in Israel are reported. We conducted optical ground-based observations aiming to detect transient luminous events (TLEs) above winter thunderstorms in Israel and in the area over the Mediterranean Sea between Israel, Cyprus and Lebanon. We alternated between two observation sites: the Tel-Aviv University campus in central Tel-Aviv (32.5N, 34.5E) and the Wise astronomical observatory in the Negev desert, near Mitzpe-Ramon (30N, 34.5E). We used 2 WATEC cameras, mounted on a pan-and- tilt unit with GPS time-base and event-detection software (UFO-Capture). The system was remote-controlled via the Internet and targets were chosen in real-time based on lightning locations derived from a BOLTEK lightning detection system stationed in Tel-Aviv. Detailed weather forecasts and careful analysis of lightning probability allowed us to choose between the two observation sites. The optical campaign was accompanied by ELF and VLF electromagnetic measurements from the existing TAU array in southern Israel. During five separate winter storms (December 2005 through March 2006) we detected 31 events: 27 sprites (4 halo sprites) and 4 elves. Detection ranges varied from 250 to 450km. Sprites were found to occur almost exclusively over the sea, in the height range 44-105km. Most sprites were columnar, and the number of elements varied from 1 to 9 with lengths varying from 10 to 48km. The average duration of sprites was ~43ms. All TLEs were accompanied by distinct positive ELF transients, which were clearly identified by our ELF station in Mizpe-Ramon and by the ELF station near Sopron, Hungary (range ~2500km). Calculated charge moment values were 800-1870 C·km, with some events exceeding 2500 C·km. We employed different lightning location systems (Israel Electrical Company LPATS and TOGA, ZEUS global networks) to determine the ground location of the parent lightning and succeeded in geo-locating 7 events. Based on weather radar and 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.

Survey of whole air data from the second airborne Biomass Burning and Lightning Experiment using principal component analysis

NASA Astrophysics Data System (ADS)

Choi, Yunsoo; Elliott, Scott; Simpson, Isobel J.; Blake, Donald R.; Colman, Jonah J.; Dubey, Manvendra K.; Meinardi, Simone; Rowland, F. Sherwood; Shirai, Tomoko; Smith, Felisa A.

2003-03-01

Hydrocarbon and halocarbon measurements collected during the second airborne Biomass Burning and Lightning Experiment (BIBLE-B) were subjected to a principal component analysis (PCA), to test the capability for identifying intercorrelated compounds within a large whole air data set. The BIBLE expeditions have sought to quantify and understand the products of burning, electrical discharge, and general atmospheric chemical processes during flights arrayed along the western edge of the Pacific. Principal component analysis was found to offer a compact method for identifying the major modes of composition encountered in the regional whole air data set. Transecting the continental monsoon, urban and industrial tracers (e.g., combustion byproducts, chlorinated methanes and ethanes, xylenes, and longer chain alkanes) dominated the observed variability. Pentane enhancements reflected vehicular emissions. In general, ethyl and propyl nitrate groupings indicated oxidation under nitrogen oxide (NOx) rich conditions and hence city or lightning influences. Over the tropical ocean, methyl nitrate grouped with brominated compounds and sometimes with dimethyl sulfide and methyl iodide. Biomass burning signatures were observed during flights over the Australian continent. Strong indications of wetland anaerobics (methane) or liquefied petroleum gas leakage (propane) were conspicuous by their absence. When all flights were considered together, sources attributable to human activity emerged as the most important. We suggest that factor reductions in general and PCA in particular may soon play a vital role in the analysis of regional whole air data sets, as a complement to more familiar methods.

The Imager for Sprites and Upper Atmospheric Lightning (ISUAL)

NASA Astrophysics Data System (ADS)

Frey, H. U.; Mende, S. B.; Harris, S. E.; Heetderks, H.; Takahashi, Y.; Su, H.-T.; Hsu, R.-R.; Chen, A. B.; Fukunishi, H.; Chang, Y.-S.; Lee, L.-C.

2016-08-01

The Imager for Sprites and Upper Atmospheric Lightning (ISUAL) was the first specifically dedicated instrument to observe lightning-induced transient luminous events (TLE): sprites, elves, halos, and gigantic jets from space. The Imager is an intensified CCD system operating in the visible wavelength region with a filter wheel to select from six positions with filters. The Imager has a 5° × 20° (vertical times horizontal) field of view. The spectrophotometer (SP) is populated with six photometers with individual filters for emissions from the far ultraviolet to the near infrared. An array photometer with two channels operating in the blue and red provides altitude profiles of the emission over 16 altitude bins each. The Associated Electronics Package (AEP) controls instrument functions and interfaces with the spacecraft. ISUAL was launched 21 May 2004 into a Sun-synchronous 890 km orbit on the Formosat-2 satellite and has successfully been collecting data ever since. ISUAL is running on the nightside of the orbit and is pointed to the east of the orbit down toward the limb. The instrument runs continuously and writes data to a circular buffer. Whenever the SP detects a sudden signal increase above a preset threshold, a trigger signal is generated that commands the system to keep the data for about 400 ms starting from ~50 ms before the trigger. Over its lifetime of ~11 years the system recorded thousands of TLE and also successfully observed aurora and airglow.

Still from Red Spot Movie

NASA Technical Reports Server (NTRS)

2000-01-01

This image is one of seven from the narrow-angle camera on NASA's Cassini spacecraft assembled as a brief movie of cloud movements on Jupiter. It was taken with a blue filter. The smallest features visible are about 500 kilometers (about 300 miles) across.

Small bright clouds appear suddenly to the west of the Great Red Spot. Based on data from NASA's Galileo spacecraft, scientists suspect that these small white features are lightning storms, where falling raindrops create an electrical charge. The lightning storms eventually merge with the Red Spot and surrounding jets, and may be the main energy source for these large-scale features. Imaging observations of the darkside of the planet in the weeks following Cassini's closest approach to Jupiter on Dec. 30, 2000 will search for lightning storms like these.

This image was re-projected by cylindrical-map projection of an image taken in the first week of October 2000. It shows an area from 50 degrees north of Jupiter's equator to 50 degrees south, extending 100 degrees east west, about one quarter of Jupiter's circumference.

Cassini is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini mission for NASA's Office of Space Science, Washington, D.C.

Design and Fabrication of an Experimental Microheater Array Powder Sintering Printer

NASA Astrophysics Data System (ADS)

Holt, Nicholas; Zhou, Wenchao

2018-03-01

Microheater array powder sintering (MAPS) is a novel additive manufacturing process that uses an array of microheaters to selectively sinter powder particles. MAPS shows great promise as a new method of printing flexible electronics by enabling digital curing of conductive inks on a variety of substrates. For MAPS to work effectively, a microscale air gap needs to be maintained between the heater array and the conductive ink. In this article, we present an experimental MAPS printer with air gap control for printing conductive circuits. First, we discuss design aspects necessary to implement MAPS. An analysis is performed to validate that the design can maintain the desired air gap between the microheaters and the sintering layer, which consists of a silver nanoparticle ink. The printer is tested by printing conductive lines on a flexible plastic substrate with silver nanoparticle ink. Results show MAPS performs on par with or better than the existing fabrication methods for printed electronics in terms of both the print quality (conductivity of the printed line) and print speed, which shows MAPS' great promise as a competitive new method for digital production of printed electronics.

Evaluation of SNP Data from the Malus Infinium Array Identifies Challenges for Genetic Analysis of Complex Genomes of Polyploid Origin.

PubMed

Troggio, Michela; Surbanovski, Nada; Bianco, Luca; Moretto, Marco; Giongo, Lara; Banchi, Elisa; Viola, Roberto; Fernández, Felicdad Fernández; Costa, Fabrizio; Velasco, Riccardo; Cestaro, Alessandro; Sargent, Daniel James

2013-01-01

High throughput arrays for the simultaneous genotyping of thousands of single-nucleotide polymorphisms (SNPs) have made the rapid genetic characterisation of plant genomes and the development of saturated linkage maps a realistic prospect for many plant species of agronomic importance. However, the correct calling of SNP genotypes in divergent polyploid genomes using array technology can be problematic due to paralogy, and to divergence in probe sequences causing changes in probe binding efficiencies. An Illumina Infinium II whole-genome genotyping array was recently developed for the cultivated apple and used to develop a molecular linkage map for an apple rootstock progeny (M432), but a large proportion of segregating SNPs were not mapped in the progeny, due to unexpected genotype clustering patterns. To investigate the causes of this unexpected clustering we performed BLAST analysis of all probe sequences against the 'Golden Delicious' genome sequence and discovered evidence for paralogous annealing sites and probe sequence divergence for a high proportion of probes contained on the array. Following visual re-evaluation of the genotyping data generated for 8,788 SNPs for the M432 progeny using the array, we manually re-scored genotypes at 818 loci and mapped a further 797 markers to the M432 linkage map. The newly mapped markers included the majority of those that could not be mapped previously, as well as loci that were previously scored as monomorphic, but which segregated due to divergence leading to heterozygosity in probe annealing sites. An evaluation of the 8,788 probes in a diverse collection of Malus germplasm showed that more than half the probes returned genotype clustering patterns that were difficult or impossible to interpret reliably, highlighting implications for the use of the array in genome-wide association studies.

The Intra-Cloud Lightning Fraction in the Contiguous United States

NASA Technical Reports Server (NTRS)

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

2015-01-01

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

[Relationships of forest fire with lightning in Daxing' anling Mountains, Northeast China].

PubMed

Lei, Xiao-Li; Zhou, Guang-Sheng; Jia, Bing-Rui; Li, Shuai

2012-07-01

Forest fire is an important factor affecting forest ecosystem succession. Recently, forest fire, especially forest lightning fire, shows an increasing trend under global warming. To study the relationships of forest fire with lightning is essential to accurately predict the forest fire in time. Daxing' anling Mountains is a region with high frequency of forest lightning fire in China, and an important experiment site to study the relationships of forest fire with lightning. Based on the forest fire records and the corresponding lightning and meteorological observation data in the Mountains from 1966 to 2007, this paper analyzed the relationships of forest fire with lightning in this region. In the period of 1966-2007, both the lightning fire number and the fired forest area in this region increased significantly. The meteorological factors affecting the forest lighting fire were related to temporal scales. At yearly scale, the forest lightning fire was significantly correlated with precipitation, with a correlation coefficient of -0.489; at monthly scale, it had a significant correlation with air temperature, the correlation coefficient being 0.18. The relationship of the forest lightning fire with lightning was also related to temporal scales. At yearly scale, there was no significant correlation between them; at monthly scale, the forest lightning fire was strongly correlated with lightning and affected by precipitation; at daily scale, a positive correlation was observed between forest lightning fire and lightning when the precipitation was less than 5 mm. According to these findings, a fire danger index based on ADTD lightning detection data was established, and a forest lightning fire forecast model was developed. The prediction accuracy of this model for the forest lightning fire in Daxing' anling Mountains in 2005-2007 was > 80%.

NASA Vision. Volume 1, No. 4

NASA Technical Reports Server (NTRS)

2003-01-01

Contents in this newsletter include the following: Honor award ceremony. NASA robotic geologist named Spirit began its seven-month journey to Mars. Around the Centers. NASA web site wins Webby Award. Global garden. Grows greener. NASA newest UAV makes successful flight. Summer interns join the NASA team. NASA maps bolts of lightning. Monumental tribute. Secret lives of galaxies unveiled in deep survey. New program sends nation's teachers "Back to school".

Development of a dense SNP-based linkage map of an apple rootstock progeny using the Malus Infinium whole genome genotyping array

PubMed Central

2012-01-01

Background A whole-genome genotyping array has previously been developed for Malus using SNP data from 28 Malus genotypes. This array offers the prospect of high throughput genotyping and linkage map development for any given Malus progeny. To test the applicability of the array for mapping in diverse Malus genotypes, we applied the array to the construction of a SNP-based linkage map of an apple rootstock progeny. Results Of the 7,867 Malus SNP markers on the array, 1,823 (23.2%) were heterozygous in one of the two parents of the progeny, 1,007 (12.8%) were heterozygous in both parental genotypes, whilst just 2.8% of the 921 Pyrus SNPs were heterozygous. A linkage map spanning 1,282.2 cM was produced comprising 2,272 SNP markers, 306 SSR markers and the S-locus. The length of the M432 linkage map was increased by 52.7 cM with the addition of the SNP markers, whilst marker density increased from 3.8 cM/marker to 0.5 cM/marker. Just three regions in excess of 10 cM remain where no markers were mapped. We compared the positions of the mapped SNP markers on the M432 map with their predicted positions on the ‘Golden Delicious’ genome sequence. A total of 311 markers (13.7% of all mapped markers) mapped to positions that conflicted with their predicted positions on the ‘Golden Delicious’ pseudo-chromosomes, indicating the presence of paralogous genomic regions or mis-assignments of genome sequence contigs during the assembly and anchoring of the genome sequence. Conclusions We incorporated data for the 2,272 SNP markers onto the map of the M432 progeny and have presented the most complete and saturated map of the full 17 linkage groups of M. pumila to date. The data were generated rapidly in a high-throughput semi-automated pipeline, permitting significant savings in time and cost over linkage map construction using microsatellites. The application of the array will permit linkage maps to be developed for QTL analyses in a cost-effective manner, and the identification of SNPs that have been assigned erroneous positions on the ‘Golden Delicious’ reference sequence will assist in the continued improvement of the genome sequence assembly for that variety. PMID:22631220

FORTE Compact Intra-cloud Discharge Detection parameterized by Peak Current

NASA Astrophysics Data System (ADS)

Heavner, M. J.; Suszcynsky, D. M.; Jacobson, A. R.; Heavner, B. D.; Smith, D. A.

2002-12-01

The Los Alamos Sferic Array (EDOT) has recorded over 3.7 million lightning-related fast electric field change data records during April 1 - August 31, 2001 and 2002. The events were detected by three or more stations, allowing for differential-time-of-arrival location determination. The waveforms are characterized with estimated peak currents as well as by event type. Narrow Bipolar Events (NBEs), the VLF/LF signature of Compact Intra-cloud Discharges (CIDs), are generally isolated pulses with identifiable ionospheric reflections, permitting determination of event source altitudes. We briefly review the EDOT characterization of events. The FORTE satellite observes Trans-Ionospheric Pulse Pairs (TIPPs, the VHF satellite signature of CIDs). The subset of coincident EDOT and FORTE CID observations are compared with the total EDOT CID database to characterize the VHF detection efficiency of CIDs. The NBE polarity and altitude are also examined in the context of FORTE TIPP detection. The parameter-dependent detection efficiencies are extrapolated from FORTE orbit to GPS orbit in support of the V-GLASS effort (GPS based global detection of lightning).

KSC-06pd1718

NASA Image and Video Library

2006-08-02

KENNEDY SPACE CENTER, FLA. - Reflected in the nearby pool of water, Space Shuttle Atlantis arrives on the hard stand on Launch Pad 39B, propelled by the crawler-transporter. At right is the 290-foot high, 300,000-gallon water tank that aids in sound suppression during launch. The water releases just prior to the ignition of the shuttle engines and flows through 7-foot-diameter pipes for about 20 seconds, pouring into 16 nozzles atop the flame deflectors and from outlets in the main engines exhaust hole in the mobile launcher platform. Atop the fixed service structure is the 80-foot lightning mast that helps provide lightning protection. The slow speed of the crawler results in a 6- to 8-hour trek to the pad approximately 4 miles away. Atlantis' launch window begins Aug. 27 for an 11-day mission to the International Space Station. The STS-115 crew of six astronauts will continue construction of the station and install their cargo, the Port 3/4 truss segment with its two large solar arrays. Photo credit: NASA/Tony Gray

[Neurological diseases after lightning strike : Lightning strikes twice].

PubMed

Gruhn, K M; Knossalla, Frauke; Schwenkreis, Peter; Hamsen, Uwe; Schildhauer, Thomas A; Tegenthoff, Martin; Sczesny-Kaiser, Matthias

2016-06-01

Lightning strikes rarely occur but 85 % of patients have lightning-related neurological complications. This report provides an overview about different modes of energy transfer and neurological conditions related to lightning strikes. Moreover, two case reports demonstrate the importance of interdisciplinary treatment and the spectrum of neurological complications after lightning strikes.

Visual Analytics approach for Lightning data analysis and cell nowcasting

NASA Astrophysics Data System (ADS)

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

2013-04-01

Thunderstorms and their ground effects, such as flash floods, hail, lightning, strong wind and tornadoes, are responsible for most weather damages (Bonelli & Marcacci 2008). Thus to understand, identify, track and predict lightning cells is essential. An important aspect for decision makers is an appropriate visualization of weather analysis results including the representation of dynamic lightning cells. This work focuses on the visual analysis of lightning data and lightning cell nowcasting which aim to detect and understanding spatial-temporal patterns of moving thunderstorms. Lightnings are described by 3D coordinates and the exact occurrence time of lightnings. The three-dimensionally resolved total lightning data used in our experiment are provided by the European lightning detection network LINET (Betz et al. 2009). In all previous works, lightning point data, detected lightning cells and derived cell tracks are visualized in 2D. Lightning cells are either displayed as 2D convex hulls with or without the underlying lightning point data. Due to recent improvements of lightning data detection and accuracy, there is a growing demand on multidimensional and interactive visualization in particular for decision makers. In a first step lightning cells are identified and tracked. Then an interactive graphic user interface (GUI) is developed to investigate the dynamics of the lightning cells: e.g. changes of cell density, location, extension as well as merging and splitting behavior in 3D over time. In particular a space time cube approach is highlighted along with statistical analysis. Furthermore a lightning cell nowcasting is conducted and visualized. The idea thereby is to predict the following cell features for the next 10-60 minutes including location, centre, extension, density, area, volume, lifetime and cell feature probabilities. The main focus will be set to a suitable interactive visualization of the predicted featured within the GUI. The developed visual exploring tool for the purpose of supporting decision making is investigated for two determined user groups: lightning experts and interested lay public. Betz HD, Schmidt K, Oettinger WP (2009) LINET - An International VLF/LF Lightning Detection Network in Europe. In: Betz HD, Schumann U, Laroche P (eds) Lightning: Principles, Instruments and Applications. Springer Netherlands, Dordrecht, pp 115-140 Bonelli P, Marcacci P (2008) Thunderstorm nowcasting by means of lightning and radar data: algorithms and applications in northern Italy. Nat. Hazards Earth Syst. Sci 8(5):1187-1198

Global Lightning Activity

NASA Technical Reports Server (NTRS)

Christian, Hugh J.

2004-01-01

Our knowledge of the global distribution of lightning has improved dramatically since the advent of spacebased lightning observations. Of major importance was the 1995 launch of the Optical Transient Detector (OTD), followed in 1997 by the launch of the Lightning Imaging Sensor (LIS). Together, these instruments have generated a continuous eight-year record of global lightning activity. These lightning observations have provided a new global perspective on total lightning activity. For the first time, total lightning activity (cloud-to-ground and intra-cloud) has been observed over large regions with high detection efficiency and accurate geographic location. This has produced new insights into lightning distributions, times of occurrence and variability. It has produced a revised global flash rate estimate (44 flashes per second) and has lead to a new realization of the significance of total lightning activity in severe weather. Accurate flash rate estimates are now available over large areas of the earth (+/- 72 deg. latitude). Ocean-land contrasts as a function of season are clearly reveled, as are orographic effects and seasonal and interannual variability. The space-based observations indicate that air mass thunderstorms, not large storm system dominate global activity. The ability of LIS and OTD to detect total lightning has lead to improved insight into the correlation between lightning and storm development. The relationship between updraft development and lightning activity is now well established and presents an opportunity for providing a new mechanism for remotely monitoring storm development. In this concept, lightning would serve as a surrogate for updraft velocity. It is anticipated that this capability could lead to significantly improved severe weather warning times and reduced false warning rates. This talk will summarize our space-based lightning measurements, will discuss how lightning observations can be used to monitor severe weather, and present a concept for continuous geostationary-based lightning observations.

Development of a 63K SNP Array for Cotton and High-Density Mapping of Intraspecific and Interspecific Populations of Gossypium spp.

PubMed Central

Hulse-Kemp, Amanda M.; Lemm, Jana; Plieske, Joerg; Ashrafi, Hamid; Buyyarapu, Ramesh; Fang, David D.; Frelichowski, James; Giband, Marc; Hague, Steve; Hinze, Lori L.; Kochan, Kelli J.; Riggs, Penny K.; Scheffler, Jodi A.; Udall, Joshua A.; Ulloa, Mauricio; Wang, Shirley S.; Zhu, Qian-Hao; Bag, Sumit K.; Bhardwaj, Archana; Burke, John J.; Byers, Robert L.; Claverie, Michel; Gore, Michael A.; Harker, David B.; Islam, Md S.; Jenkins, Johnie N.; Jones, Don C.; Lacape, Jean-Marc; Llewellyn, Danny J.; Percy, Richard G.; Pepper, Alan E.; Poland, Jesse A.; Mohan Rai, Krishan; Sawant, Samir V.; Singh, Sunil Kumar; Spriggs, Andrew; Taylor, Jen M.; Wang, Fei; Yourstone, Scott M.; Zheng, Xiuting; Lawley, Cindy T.; Ganal, Martin W.; Van Deynze, Allen; Wilson, Iain W.; Stelly, David M.

2015-01-01

High-throughput genotyping arrays provide a standardized resource for plant breeding communities that are useful for a breadth of applications including high-density genetic mapping, genome-wide association studies (GWAS), genomic selection (GS), complex trait dissection, and studying patterns of genomic diversity among cultivars and wild accessions. We have developed the CottonSNP63K, an Illumina Infinium array containing assays for 45,104 putative intraspecific single nucleotide polymorphism (SNP) markers for use within the cultivated cotton species Gossypium hirsutum L. and 17,954 putative interspecific SNP markers for use with crosses of other cotton species with G. hirsutum. The SNPs on the array were developed from 13 different discovery sets that represent a diverse range of G. hirsutum germplasm and five other species: G. barbadense L., G. tomentosum Nuttal × Seemann, G. mustelinum Miers × Watt, G. armourianum Kearny, and G. longicalyx J.B. Hutchinson and Lee. The array was validated with 1,156 samples to generate cluster positions to facilitate automated analysis of 38,822 polymorphic markers. Two high-density genetic maps containing a total of 22,829 SNPs were generated for two F2 mapping populations, one intraspecific and one interspecific, and 3,533 SNP markers were co-occurring in both maps. The produced intraspecific genetic map is the first saturated map that associates into 26 linkage groups corresponding to the number of cotton chromosomes for a cross between two G. hirsutum lines. The linkage maps were shown to have high levels of collinearity to the JGI G. raimondii Ulbrich reference genome sequence. The CottonSNP63K array, cluster file and associated marker sequences constitute a major new resource for the global cotton research community. PMID:25908569

Terrestrial Gamma Flashes at Ground Level - TETRA-II Instrumentation

NASA Astrophysics Data System (ADS)

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

2017-12-01

The TGF and Energetic Thunderstorm Rooftop Array (TETRA-II) consists of an array of BGO scintillators to detect bursts of gamma rays from thunderstorms. TETRA-II will have approximately an order of magnitude greater sensitivity for individual flashes than TETRA-I, an original array of NaI scintillators at Louisiana State University that detected 37 millisecond-scale bursts of gamma rays from 2010-2015. The BGO scintillators increase the energy range of particles detected to 10 MeV and are placed in 20 detectors boxes, each with 1180 cm3 of BGO, at 4 separate locations: the campus of Louisiana State University in Baton Rouge, Louisiana; the campus of the University of Puerto Rico at Utuado, Puerto Rico; the Centro Nacional de Metrologia de Panama (CENAMEP) in Panama City, Panama; and the Severe Weather Institute and Radar & Lightning Laboratories in Huntsville, Alabama. The data are read out with 12 microsecond resolution by National Instruments PCIe 6351 high speed data acquisition cards, with timestamps determined from a 20 MHz clock and a GPS board recording a pulse per second. Details of the array and its instrumentation, along with an overview of initial results, will be presented.

Number of lightning discharges causing damage to lightning arrester cables for aerial transmission lines in power systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nikiforov, E. P.

2009-07-15

Damage by lightning discharges to lightning arrester cables for 110-175 kV aerial transmission lines is analyzed using data from power systems on incidents with aerial transmission lines over a ten year operating period (1997-2006). It is found that failures of lightning arrester cables occur when a tensile force acts on a cable heated to the melting point by a lightning current. The lightning currents required to heat a cable to this extent are greater for larger cable cross sections. The probability that a lightning discharge will develop decreases as the amplitude of the lightning current increases, which greatly reduces themore » number of lightning discharges which damage TK-70 cables compared to TK-50 cables. In order to increase the reliability of lightning arrester cables for 110 kV aerial transmission lines, TK-70 cables should be used in place of TK-50 cables. The number of lightning discharges per year which damage lightning arrester cables is lowered when the density of aerial transmission lines is reduced within the territory of electrical power systems. An approximate relationship between these two parameters is obtained.« less

Severe weather detection by using Japanese Total Lightning Network

NASA Astrophysics Data System (ADS)

Hobara, Yasuhide; Ishii, Hayato; Kumagai, Yuri; Liu, Charlie; Heckman, Stan; Price, Colin

2015-04-01

In this paper we demonstrate the preliminary results from the first Japanese Total Lightning Network. The University of Electro-Communications (UEC) recently deployed Earth Networks Total Lightning System over Japan to conduct various lightning research projects. Here we analyzed the total lightning data in relation with 10 severe events such as gust fronts and tornadoes occurred in 2014 in mainland Japan. For the analysis of these events, lightning jump algorithm was used to identify the increase of the flash rate in prior to the severe weather events. We found that lightning jumps associated with significant increasing lightning activities for total lightning and IC clearly indicate the severe weather occurrence than those for CGs.

Nowcasting and forecasting of lightning activity: the Talos project.

NASA Astrophysics Data System (ADS)

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

2015-04-01

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

Lightning Safety Tips and Resources

MedlinePlus

... Safety Brochure U.S. Lightning Deaths in 2018 : 5 Youtube: Lightning Safety for the Deaf and Hard of ... for Hard of Hearing: jpg , high res png YouTube: Lightning Safety Tips Lightning Safety When Working Outdoors : ...

Nitrogen Oxides and Ozones from B-747 Measurements (NOXAR) during POLINAT 2 and SONEX: Overview and Case-Studies on Continental and Marine Convection

NASA Technical Reports Server (NTRS)

Jeker, Dominique; Pfister, Lenny; Brunner, Dominik; Boccippio, Dennis J.; Pickering, Kenneth E.; Thompson, Anne M.; Wernli, Heini; Selkirk, Rennie B.; Kondo, Yutaka; Koike, Matoke;

NASA Manned Launch Vehicle Lightning Protection Development

NASA Technical Reports Server (NTRS)

McCollum, Matthew B.; Jones, Steven R.; Mack, Jonathan D.

2009-01-01

Historically, the National Aeronautics and Space Administration (NASA) relied heavily on lightning avoidance to protect launch vehicles and crew from lightning effects. As NASA transitions from the Space Shuttle to the new Constellation family of launch vehicles and spacecraft, NASA engineers are imposing design and construction standards on the spacecraft and launch vehicles to withstand both the direct and indirect effects of lightning. A review of current Space Shuttle lightning constraints and protection methodology will be presented, as well as a historical review of Space Shuttle lightning requirements and design. The Space Shuttle lightning requirements document, NSTS 07636, Lightning Protection, Test and Analysis Requirements, (originally published as document number JSC 07636, Lightning Protection Criteria Document) was developed in response to the Apollo 12 lightning event and other experiences with NASA and the Department of Defense launch vehicles. This document defined the lightning environment, vehicle protection requirements, and design guidelines for meeting the requirements. The criteria developed in JSC 07636 were a precursor to the Society of Automotive Engineers (SAE) lightning standards. These SAE standards, along with Radio Technical Commission for Aeronautics (RTCA) DO-160, Environmental Conditions and Test Procedures for Airborne Equipment, are the basis for the current Constellation lightning design requirements. The development and derivation of these requirements will be presented. As budget and schedule constraints hampered lightning protection design and verification efforts, the Space Shuttle elements waived the design requirements and relied on lightning avoidance in the form of launch commit criteria (LCC) constraints and a catenary wire system for lightning protection at the launch pads. A better understanding of the lightning environment has highlighted the vulnerability of the protection schemes and associated risk to the vehicle, which has resulted in lost launch opportunities and increased expenditures in manpower to assess Space Shuttle vehicle health and safety after lightning events at the launch pad. Because of high-percentage launch availability and long-term on-pad requirements, LCC constraints are no longer considered feasible. The Constellation vehicles must be designed to withstand direct and indirect effects of lightning. A review of the vehicle design and potential concerns will be presented as well as the new catenary lightning protection system for the launch pad. This system is required to protect the Constellation vehicles during launch processing when vehicle lightning effects protection might be compromised by such items as umbilical connections and open access hatches.

International Aerospace and Ground Conference on Lightning and Static Electricity, 10th, and Congres International Aeronautique, 17th, Paris, France, June 10-13, 1985, Proceedings

NASA Astrophysics Data System (ADS)

1985-12-01

The conference presents papers on statistical data and standards, coupling and indirect effects, meteorology and thunderstorm studies, lightning simulators, fuel ignition hazards, the phenomenology and characterization of lightning, susceptibility and protection of avionics, ground systems protection, lightning locators, aircraft systems protection, structures and materials, electrostatics, and spacecraft protection against static electricity. Particular attention is given to a comparison of published HEMP and natural lightning on the surface of an aircraft, electromagnetic interaction of external impulse fields with aircraft, of thunderstorm currents and lightning charges at the NASA Kennedy Space Center, the design of a fast risetime lightning generator, lightning simulation tests in FAA CV-580 lightning research aircraft, and the energy requirements of an aircraft triggered discharge. Papers are also presented on aircraft lightning attachment at low altitudes, a new form of transient suppressor, a proving ground for lightning research, and a spacecraft materials test in a continuous, broad energy-spectrum electron beam.

The electric field changes and UHF radiations caused by the triggered lightning in Japan

NASA Technical Reports Server (NTRS)

Kawasaki, Zen-Ichiro; Kanao, Tadashi; Matsuura, Kenji; Nakano, Minoru; Horii, Kenji; Nakamura, Koichi

1991-01-01

In the rocket triggered lightning experiment of fiscal 1989, researchers observed electromagnetic field changes and UHF electromagnetic radiation accompanying rocket triggered lightning. It was found that no rapid changes corresponding to the return stroke of natural lightning were observed in the electric field changes accompanying rocket triggered lightning. However, continuous currents were present. In the case of rocket triggered lightning to the tower, electromagnetic field changes corresponding to the initiation of triggered lightning showed a bipolar pulse of a relatively large amplitude. In contrast, the rocket triggered lightning to the ground did not have such a bipolar pulse. The UHF radiation accompanying the rocket triggered lightning preceded the waveform portions corresponding to the first changes in electromagnetic fields. The number of isolated pulses in the UHF radiation showed a correlation with the time duration from rocket launching up to triggered lightning. The time interval between consecutive isolated pulses tended to get shorter with the passage of time, just like the stepped leaders of natural lightning.

Cross-Referencing GLM and ISS-LIS with Ground-Based Lightning Networks

NASA Astrophysics Data System (ADS)

Virts, K.; Blakeslee, R. J.; Goodman, S. J.; Koshak, W. J.

2017-12-01

The Geostationary Lightning Mapper (GLM), in geostationary orbit aboard GOES-16 since late 2016, and the Lightning Imaging Sensor (LIS), installed on the International Space Station in February 2017, provide observations of total lightning activity from space. ISS-LIS samples the global tropics and mid-latitudes, while GLM observes the full thunderstorm life-cycle over the Americas and surrounding oceans. The launch of these instruments provides an unprecedented opportunity to compare lightning observations across multiple space-based optical lightning sensors. In this study, months of observations from GLM and ISS-LIS are cross-referenced with each other and with lightning detected by the ground-based Earth Networks Global Lightning Network (ENGLN) and the Vaisala Global Lightning Dataset 360 (GLD360) throughout and beyond the GLM field-of-view. In addition to calibration/validation of the new satellite sensors, this study provides a statistical comparison of the characteristics of lightning observed by the satellite and ground-based instruments, with an emphasis on the lightning flashes uniquely identified by the satellites.

Lightning-Related Indicators for National Climate Assessment (NCA) Studies

NASA Astrophysics Data System (ADS)

Koshak, W. J.

2017-12-01

With the recent advent of space-based lightning mappers [i.e., the Geostationary Lightning Mapper (GLM) on GOES-16, and the Lightning Imaging Sensor (LIS) on the International Space Station], improved investigations on the inter-relationships between lightning and climate are now possible and can directly support the goals of the National Climate Assessment (NCA) program. Lightning nitrogen oxides (LNOx) affect greenhouse gas concentrations such as ozone that influences changes in climate. Conversely, changes in climate (from any causes) can affect the characteristics of lightning (e.g., frequency, current amplitudes, multiplicity, polarity) that in turn leads to changes in lightning-caused impacts to humans (e.g., fatalities, injuries, crop/property damage, wildfires, airport delays, changes in air quality). This study discusses improvements to, and recent results from, the NASA/MSFC NCA Lightning Analysis Tool (LAT). It includes key findings on the development of different types of lightning flash energy indicators derived from space-based lightning observations, and demonstrates how these indicators can be used to estimate trends in LNOx across the continental US.

Lightning Technology: Proceedings of a Technical Symposium

NASA Technical Reports Server (NTRS)

1980-01-01

Several facets of lightning technology are considered including phenomenology, measurement, detection, protection, interaction, and testing. Lightning electromagnetics, protection of ground systems, and simulated lightning testing are emphasized. The lightning-instrumented F-106 aircraft is described.

Phased Array Ultrasonic Sound Field Mapping in Cast Austenitic Stainless Steel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crawford, Susan L.; Prowant, Matthew S.; Cinson, Anthony D.

2014-05-31

This study maps the phased array-generated acoustic sound fields through three types of CASS microstructure in four specimens to quantitatively assess the beam formation effectiveness in these materials.

An In Depth Look at Lightning Trends in Hurricane Harvey using Satellite and Ground-Based Measurements

NASA Astrophysics Data System (ADS)

Ringhausen, J.

2017-12-01

This research combines satellite measurements of lightning in Hurricane Harvey with ground-based lightning measurements to get a better sense of the total lightning occurring in the hurricane, both intra-cloud (IC) and cloud-to-ground (CG), and how it relates to the intensification and weakening of the tropical system. Past studies have looked at lightning trends in hurricanes using the space based Lightning Imaging Sensor (LIS) or ground-based lightning detection networks. However, both of these methods have drawbacks. For instance, LIS was in low earth orbit, which limited lightning observations to 90 seconds for a particular point on the ground; hence, continuous lightning coverage of a hurricane was not possible. Ground-based networks can have a decreased detection efficiency, particularly for ICs, over oceans where hurricanes generally intensify. With the launch of the Geostationary Lightning Mapper (GLM) on the GOES-16 satellite, researchers can study total lightning continuously over the lifetime of a tropical cyclone. This study utilizes GLM to investigate total lightning activity in Hurricane Harvey temporally; this is augmented with spatial analysis relative to hurricane structure, similar to previous studies. Further, GLM and ground-based network data are combined using Bayesian techniques in a new manner to leverage the strengths of each detection method. This methodology 1) provides a more complete estimate of lightning activity and 2) enables the derivation of the IC:CG ratio (Z-ratio) throughout the time period of the study. In particular, details of the evolution of the Z-ratio in time and space are presented. In addition, lightning stroke spatiotemporal trends are compared to lightning flash trends. This research represents a new application of lightning data that can be used in future study of tropical cyclone intensification and weakening.

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

PubMed

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

2013-01-01

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

Comparison of Computational and Experimental Microphone Array Results for an 18%-Scale Aircraft Model

NASA Technical Reports Server (NTRS)

Lockard, David P.; Humphreys, William M.; Khorrami, Mehdi R.; Fares, Ehab; Casalino, Damiano; Ravetta, Patricio A.

2015-01-01

An 18%-scale, semi-span model is used as a platform for examining the efficacy of microphone array processing using synthetic data from numerical simulations. Two hybrid RANS/LES codes coupled with Ffowcs Williams-Hawkings solvers are used to calculate 97 microphone signals at the locations of an array employed in the NASA LaRC 14x22 tunnel. Conventional, DAMAS, and CLEAN-SC array processing is applied in an identical fashion to the experimental and computational results for three different configurations involving deploying and retracting the main landing gear and a part span flap. Despite the short time records of the numerical signals, the beamform maps are able to isolate the noise sources, and the appearance of the DAMAS synthetic array maps is generally better than those from the experimental data. The experimental CLEAN-SC maps are similar in quality to those from the simulations indicating that CLEAN-SC may have less sensitivity to background noise. The spectrum obtained from DAMAS processing of synthetic array data is nearly identical to the spectrum of the center microphone of the array, indicating that for this problem array processing of synthetic data does not improve spectral comparisons with experiment. However, the beamform maps do provide an additional means of comparison that can reveal differences that cannot be ascertained from spectra alone.

Measuring Method for Lightning Channel Temperature.

PubMed

Li, X; Zhang, J; Chen, L; Xue, Q; Zhu, R

2016-09-26

In this paper, we demonstrate the temperature of lightning channel utilizing the theory of lightning spectra and the model of local thermodynamic equilibrium (LTE). The impulse current generator platform (ICGS) was used to simulate the lightning discharge channel, and the spectral energy of infrared spectroscopy (930 nm) and the visible spectroscopy (648.2 nm) of the simulated lightning has been calculated. Results indicate that the peaks of luminous intensity of both infrared and visible spectra increase with the lightning current intensity in range of 5-50 kA. Based on the results, the temperature of the lightning channel is derived to be 6140.8-10424 K. Moreover, the temperature of the channel is approximately exponential to the lightning current intensity, which shows good agreement with that of the natural lightning cases.

Measuring Method for Lightning Channel Temperature

NASA Astrophysics Data System (ADS)

Li, X.; Zhang, J.; Chen, L.; Xue, Q.; Zhu, R.

2016-09-01

In this paper, we demonstrate the temperature of lightning channel utilizing the theory of lightning spectra and the model of local thermodynamic equilibrium (LTE). The impulse current generator platform (ICGS) was used to simulate the lightning discharge channel, and the spectral energy of infrared spectroscopy (930 nm) and the visible spectroscopy (648.2 nm) of the simulated lightning has been calculated. Results indicate that the peaks of luminous intensity of both infrared and visible spectra increase with the lightning current intensity in range of 5-50 kA. Based on the results, the temperature of the lightning channel is derived to be 6140.8-10424 K. Moreover, the temperature of the channel is approximately exponential to the lightning current intensity, which shows good agreement with that of the natural lightning cases.

Optimizing Precipitation Thresholds for Best Correlation Between Dry Lightning and Wildfires

NASA Astrophysics Data System (ADS)

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

2018-03-01

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

Lightning attachment process to common buildings

NASA Astrophysics Data System (ADS)

Saba, M. M. F.; Paiva, A. R.; Schumann, C.; Ferro, M. A. S.; Naccarato, K. P.; Silva, J. C. O.; Siqueira, F. V. C.; Custódio, D. M.

2017-05-01

The physical mechanism of lightning attachment to grounded structures is one of the most important issues in lightning physics research, and it is the basis for the design of the lightning protection systems. Most of what is known about the attachment process comes from leader propagation models that are mostly based on laboratory observations of long electrical discharges or from observations of lightning attachment to tall structures. In this paper we use high-speed videos to analyze the attachment process of downward lightning flashes to an ordinary residential building. For the first time, we present characteristics of the attachment process to common structures that are present in almost every city (in this case, two buildings under 60 m in São Paulo City, Brazil). Parameters like striking distance and connecting leaders speed, largely used in lightning attachment models and in lightning protection standards, are revealed in this work.