scholarly journals Total Lightning Signatures of Thunderstorm Intensity over North Texas. Part I: Supercells

2007 ◽  
Vol 135 (10) ◽  
pp. 3281-3302 ◽  
Author(s):  
Scott M. Steiger ◽  
Richard E. Orville ◽  
Lawrence D. Carey
Keyword(s):  
Fort Worth ◽  
North Texas ◽  
Lightning Detection ◽  
Cloud To Ground Lightning ◽  
Total Lightning

Abstract It is shown that total lightning mapping, along with radar and National Lightning Detection Network (NLDN) cloud-to-ground lightning data, can be used to diagnose the severity of a thunderstorm. Analysis of supercells, some of which were tornadic, on 13 October 2001 over Dallas–Fort Worth, Texas, shows that Lightning Detection and Ranging (LDAR II) lightning source heights (quartile, median, and 95th percentile heights) increased as the storms intensified. Most of the total (cloud to ground and intracloud) lightning occurred where reflectivity cores extended upward, within regions of strong reflectivity gradient rather than in reflectivity cores. A total lightning hole was associated with an intense, nontornadic supercell on 6 April 2003. None of the supercells on 13 October 2001 exhibited a lightning hole. During tornadogenesis, the radar and LDAR II data indicated updraft weakening. The height of the 30-dBZ radar top began to descend approximately 10 min (2 volume scans) before tornado touchdown in one storm. Total lightning and cloud-to-ground flash rates decreased by up to a factor of 5 to a minimum during an F2 tornado touchdown associated with this storm. LDAR II source heights all showed descent by 2–4 km during a 25-min period prior to and during this tornado touchdown. This drastic trend of decreasing source heights prior to and during tornado touchdown was observed in two storms, but did not occur in nontornadic supercells, suggesting that these parameters can be useful to forecasters. These observations agree with tornadogenesis theory that as the updraft weakens, the mesocyclone can divide (into an updraft and downdraft) and become tornadic.

scholarly journals The Timing of Cloud-to-Ground Lightning Relative to Total Lightning Activity

2011 ◽  
Vol 139 (12) ◽  
pp. 3871-3886 ◽  
Author(s):  
Donald R. MacGorman ◽  
Ivy R. Apostolakopoulos ◽  
Nicole R. Lund ◽  
Nicholas W. S. Demetriades ◽  
Martin J. Murphy ◽  
...  
Keyword(s):  
Lightning Activity ◽  
High Plains ◽  
Very High Frequency ◽  
North Texas ◽  
Lightning Detection ◽  
Lower Charge ◽  
Cloud To Ground Lightning ◽  
Total Lightning ◽  
Very High ◽  
Mapping Systems

Abstract The first flash produced by a storm usually does not strike ground, but little has been published concerning the time after the first flash before a cloud-to-ground flash occurs, particularly for a variety of climatological regions. To begin addressing this issue, this study analyzed data from very-high-frequency (VHF) lightning mapping systems, which detect flashes of all types, and from the U.S. National Lightning Detection Network (NLDN), which identifies flash type and detects roughly 90% of cloud-to-ground flashes overall. VHF mapping data were analyzed from three regions: north Texas, Oklahoma, and the high plains of Colorado, Kansas, and Nebraska. The percentage of storms in which a cloud-to-ground flash was detected in the first minute of lightning activity varied from 0% in the high plains to 10%–20% in Oklahoma and north Texas. The distribution of delays to the first cloud-to-ground flash varied similarly. In Oklahoma and north Texas, 50% of storms produced a cloud-to-ground flash within 5–10 min, and roughly 10% failed to produce a cloud-to-ground flash within 1 h. In the high plains, however, it required 30 min for 50% of storms to have produced a cloud-to-ground flash, and 20% produced no ground flash within 1 h. The authors suggest that the reason high plains storms take longer to produce cloud-to-ground lightning is because the formation of the lower charge needed to produce most cloud-to-ground flashes is inhibited either by delaying the formation of precipitation in the mid- and lower levels of storms or by many of the storms having an inverted-polarity electrical structure.

The Relationship between Total Cloud Lightning Behavior and Radar-Derived Thunderstorm Structure

2013 ◽  
Vol 28 (1) ◽  
pp. 237-253 ◽  
Author(s):  
Eric Metzger ◽  
Wendell A. Nuss
Keyword(s):  
Weather Type ◽  
Severe Weather ◽  
Characteristic Change ◽  
Lightning Flash ◽  
Fort Worth ◽  
Detection Systems ◽  
Lightning Detection ◽  
Rapid Changes ◽  
Total Lightning ◽  
The Relationship

Abstract Total lightning detection systems have been in development since the mid-1980s and deployed in several areas around the world. Previous studies on total lightning found intra- and intercloud lightning (IC) activity tends to fluctuate significantly during the lifetime of thunderstorms and have indicated that lightning jumps or rapid changes in lightning flash rates are closely linked to changes in the vertical integrated liquid (VIL) reading on the National Weather Service’s Weather Surveillance Radar-1988 Doppler (WSR-88D) systems. This study examines the total lightning and its relationship to WSR-88D signatures used operationally to determine thunderstorm severity to highlight the potential benefit of a combined forecast approach. Lightning and thunderstorm data from the Dallas–Fort Worth, Texas, and Tucson, Arizona, areas from 2006 to 2009, were used to relate total lightning behavior and radar interrogation techniques. The results indicate that lightning jumps can be classified into severe wind, hail, or mixed-type jumps based on the behavior of various radar-based parameters. In 25 of 34 hail-type jumps and in 18 of 20 wind-type jumps, a characteristic change in cloud-to-ground (CG) versus IC lightning flash rates occurred prior to the report of severe weather. For hail-type jumps, IC flash rates increased, while CG flash rates were steady or decreased. For wind-type jumps, CG flash rates increased, while IC flash rates either increased (12 of 18) or were steady or decreased (6 of 18). Although not every lightning jump resulted in a severe weather report, the characteristic behavior in flash rates adds information to radar-based approaches for nowcasting the severe weather type.

scholarly journals Total Lightning Signatures of Thunderstorm Intensity over North Texas. Part II: Mesoscale Convective Systems

2007 ◽  
Vol 135 (10) ◽  
pp. 3303-3324 ◽  
Author(s):  
Scott M. Steiger ◽  
Richard E. Orville ◽  
Lawrence D. Carey
Keyword(s):  
Mesoscale Convective Systems ◽  
Research Network ◽  
Fort Worth ◽  
Convective Systems ◽  
Source Density ◽  
Stratiform Region ◽  
Straight Line ◽  
Lightning Detection ◽  
Mesoscale Convective ◽  
Total Lightning

Abstract Total lightning data from the Lightning Detection and Ranging (LDAR II) research network in addition to cloud-to-ground flash data from the National Lightning Detection Network (NLDN) and data from the Dallas–Fort Worth, Texas, Weather Surveillance Radar-1988 Doppler (WSR-88D) station (KFWS) were examined from individual cells within mesoscale convective systems that crossed the Dallas–Fort Worth region on 13 October 2001, 27 May 2002, and 16 June 2002. LDAR II source density contours were comma shaped, in association with severe wind events within mesoscale convective systems (MCSs) on 13 October 2001 and 27 May 2002. This signature is similar to the radar reflectivity bow echo. The source density comma shape was apparent 15 min prior to a severe wind report and lasted more than 20 min during the 13 October storm. Consistent relationships between severe straight-line winds, radar, and lightning storm cell characteristics (e.g., lightning heights) were not found for cells within MCSs as was the case for severe weather in supercells in Part I of this study. Cell interactions within MCSs are believed to weaken these relationships as reflectivity and lightning from nearby storms contaminate the cells of interest. Another hypothesis for these weak relations is that system, not individual cell, processes are responsible for severe straight-line winds at the surface. Analysis of the total lightning structure of the 13 October 2001 MCS showed downward-sloping source density contours behind the main convective line into the stratiform region. This further supports a charge advection mechanism in developing the stratiform charge structure. Bimodal vertical source density distributions were observed within MCS convection close to the center of the LDAR II network, while the lower mode was not detected at increasing range.

Development of the National Lightning Detection Network

2008 ◽  
Vol 89 (2) ◽  
pp. 180-190 ◽  
Author(s):  
Richard E. Orville
Keyword(s):  
New York ◽  
National Science Foundation ◽  
Satellite Communications ◽  
Western Hemisphere ◽  
State University ◽  
Lightning Detection ◽  
History Of ◽  
Cloud To Ground Lightning ◽  
Total Lightning ◽  
The University

The development of the National Lightning Detection Network (NLDN) can be traced from the initial funding by the Electric Power Research Institute in June 1983. This support, when coupled with a small National Science Foundation-sponsored research program at the State University of New York at Albany, would lead in just six years to the coverage of 48 states by a network of lightning detectors providing the location and physical characteristics of nearly all cloud-to-ground lightning flashes in the continental United States. The generous sharing of data from existing federal lightning detection networks provided one-third of this national coverage. The measured lightning characteristics included stroke location to an accuracy of roughly 2 km, polarity and peak current estimates, and flash multiplicity or number of strokes within the flash. The development of satellite communications during this period ensured the receipt of data and the transmission of flash characteristics to consumers in the university, government, and private sectors. The history of the NLDN development is a story driven by technology with its roots in the 1970s. The future of lightning detection is embodied within the current satellite plans for a Geostationary Lightning Mapper to observe total lightning in the Western Hemisphere as part of the Geostationary Operational Environmental Satellite-R (GOESR) program, with launch dates as early as 2014.

Detecting Multiple Ground Contacts in Cloud-to-Ground Lightning Flashes

2009 ◽  
Vol 26 (11) ◽  
pp. 2392-2402 ◽  
Author(s):  
Christina A. Stall ◽  
Kenneth L. Cummins ◽  
E. Philip Krider ◽  
John A. Cramer
Keyword(s):  
Standard Deviation ◽  
Rise Time ◽  
Random Errors ◽  
Peak Current ◽  
Video Recordings ◽  
Lightning Detection ◽  
Cloud To Ground Lightning ◽  
The U.S ◽  
Good Agreement ◽  
Cg Lightning

Abstract Video recordings of cloud-to-ground (CG) lightning flashes have been analyzed in conjunction with correlated stroke reports from the U.S. National Lightning Detection Network (NLDN) to determine whether the NLDN is capable of identifying the different ground contacts in CG flashes. For 39 negative CG flashes that were recorded on video near Tucson, Arizona, the NLDN-based horizontal distances between the first stroke and the 62 subsequent strokes remaining in a preexisting channel had a mean and standard deviation of 0.9 ± 0.8 km and a median of 0.7 km. The horizontal distances between the first stroke and the 59 new ground contacts (NGCs) had a mean and standard deviation of 2.3 ± 1.7 km and a median of 2.1 km. These results are in good agreement with prior measurements of the random errors in NLDN positions in southern Arizona as well as video- and thunder-based measurements of the distances between all ground contacts in Florida. In cases where the distances between ground contacts are small and obscured by random errors in the NLDN locations, measurements of the stroke rise time, estimated peak current, and stroke order can be utilized to enhance the ability of the NLDN to identify strokes that produce new ground terminations.

scholarly journals Algorithm for Improved QPE over Complex Terrain Using Cloud-to-Ground Lightning Occurrences

Atmosphere ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 85
Author(s):  
Carlos Minjarez-Sosa ◽  
Julio Waissman ◽  
Christopher Castro ◽  
David Adams
Keyword(s):  
Complex Terrain ◽  
Convective Precipitation ◽  
North American Monsoon ◽  
Monsoon Region ◽  
Convective Rainfall ◽  
The Third ◽  
The North ◽  
Lightning Detection ◽  
Cloud To Ground Lightning ◽  
Noise Test

Lightning and deep convective precipitation have long been studied as closely linked variables, the former being viewed as a proxy, or estimator, of the latter. However, to date, no single methodology or algorithm exists for estimating lightning-derived precipitation in a gridded form. This paper, the third in a series, details the specific algorithm where convective rainfall was estimated with cloud-to-ground lightning occurrences from the U.S. National Lightning Detection Network (NLDN), for the North American Monsoon region. Specifically, the authors present the methodology employed in their previous studies to get this estimation, noise test, spatial and temporal neighbors and the algorithm of the Kalman filter for dynamically derived precipitation from lightning.

Why Aren’t More People Telecommuting?: Explanations from Four Studies

1997 ◽  
Vol 1607 (1) ◽  
pp. 196-203 ◽  
Author(s):  
Joanne H. Pratt
Keyword(s):  
Training Program ◽  
Fort Worth ◽  
Bottom Line ◽  
North Texas ◽  
The North ◽  
Work From Home ◽  
Clean Air ◽  
Private Effort ◽  
The City

Despite the proven “bottom-line” benefits of telework, companies are still reluctant to implement new ways of organizing their workforces. That is particularly true of the practice of allowing employees to work from home offices. The findings of four studies that identify factors that must be considered in overcoming the barriers to telework are presented: (a) a report of the Telecommute America! public-private effort to promote awareness and understanding of telecommuting and telework; (b) a survey of Houston, Texas, employers required to submit trip reduction plans under the Clean Air Acts; (c) an evaluation of the city and county of Denver, Colorado, TRP 2000 training program, and (d) the Dallas-Fort Worth, Texas, telecommuting assistance initiative of the North Texas Clean Air Coalition.

scholarly journals A 10-Year Study on the Characteristics of Thunderstorms in Belgium Based on Cloud-to-Ground Lightning Data

2014 ◽  
Vol 142 (12) ◽  
pp. 4839-4849 ◽  
Author(s):  
Dieter R. Poelman
Keyword(s):  
Cell Tracking ◽  
Total Activity ◽  
The West ◽  
European Cooperation ◽  
Lightning Detection ◽  
Cloud To Ground Lightning ◽  
A Cell ◽  
Direction Of Movement ◽  
Temporal And Spatial ◽  
The Individual

Abstract Temporal and spatial distributions of cloud-to-ground (CG) lightning in Belgium are analyzed. Based on data from the European Cooperation for Lightning Detection (EUCLID) network, spanning a period of 10 years between 2004 and 2013, mean CG flash densities vary between 0.3 km−2 yr−1 in the west up to 2.4 km−2 yr−1 toward the east of Belgium, with an average flash density of 0.7 km−2 yr−1. The same behavior is found in terms of thunderstorm days and hours, where in the east most of the activity is observed, with a drop-off toward the coast. The majority of lightning activity takes place in the summer months between May and August, accounting for nearly 90% of the total activity. Furthermore, the thunderstorm season reaches its highest activity in July in terms of CG detections, while the diurnal cycle peaks between 1500 and 1600 UTC. A correlation is found between the estimated peak currents and altitude, with on average higher absolute peak currents at lower elevations and vice versa. In addition, a cell tracking algorithm is applied to the data to monitor the behavior of the individual cells. It is found that the lightning cells travel at an average speed of about 25 km h−1, with a preferred northeasterly direction of movement. At last, CG flash rates are strongly related to the cell area.

An Electrical and Polarimetric Analysis of the Overland Reintensification of Tropical Storm Erin (2007)

2014 ◽  
Vol 142 (6) ◽  
pp. 2321-2344 ◽  
Author(s):  
Erica M. Griffin ◽  
Terry J. Schuur ◽  
Donald R. MacGorman ◽  
Matthew R. Kumjian ◽  
Alexandre O. Fierro
Keyword(s):  
Tropical Cyclones ◽  
Inner Core ◽  
Open Water ◽  
Tropical Storm ◽  
Sea Level Pressure ◽  
Core Convection ◽  
Lightning Detection ◽  
Mapping Array ◽  
Total Lightning ◽  
Abundant Data

Abstract While passing over central Oklahoma on 18–19 August 2007, the remnants of Tropical Storm Erin unexpectedly reintensified and developed an eyelike feature that was clearly discernable in Weather Surveillance Radar-1988 Doppler (WSR-88D) imagery. During this brief reintensification period, Erin traversed a region of dense surface and remote sensing observation networks that provided abundant data of high spatial and temporal resolution. This study analyzes data from the polarimetric KOUN S-band radar, total lightning data from the Oklahoma Lightning Mapping Array, and ground-flash lightning data from the National Lightning Detection Network. Erin’s reintensification was atypical since it occurred well inland and was accompanied by stronger maximum sustained winds and gusts (25 and 37 m s−1, respectively) and lower minimum sea level pressure (1001.3 hPa) than while over water. Radar observations reveal several similarities to those documented in mature tropical cyclones over open water, including outward-sloping eyewall convection, near 0-dBZ reflectivities within the eye, and relatively large updraft velocities in the eyewall as inferred from single-Doppler winds and ZDR columns. Deep, electrified convection near the center of circulation preceded the formation of Erin’s eye, with maximum lightning activity occurring prior to and during reintensification. The results show that inner-core convection may have played a role in the reinvigoration of the storm.

Attribute illumination of basement faults, examples from Cuu Long Basin basement, Vietnam and the Midcontinent, USA

2014 ◽  
Vol 2 (1) ◽  
pp. SA119-SA126 ◽  
Author(s):  
Ha T. Mai ◽  
Olubunmi O. Elebiju ◽  
Kurt J. Marfurt
Keyword(s):  
Sedimentary Basins ◽  
Fort Worth ◽  
North Texas ◽  
Fort Worth Basin ◽  
Diagenetic Alteration ◽  
Basement Faults ◽  
The Usa ◽  
Lead Zinc ◽  
Granite Basement ◽  
Osage County

Geometric attributes such as coherence and curvature have been very successful in delineating faults in sedimentary basins. Albeit not a common exploration objective, fractured and faulted basement forms important reservoirs in Southern California, Mexico, India, Yemen, and Vietnam. Basement faulting controls hydrothermally altered dolomite in the Appalachian Basin of the USA, and is suspected to play a role in diagenetic alteration of carbonates in the Fort Worth Basin of north Texas where copper has been found in some wells, as well as in Osage County, Oklahoma, not far from the classic Mississippi type lead-zinc deposits. Because of the absence of stratified, coherent reflectors, illumination of basement faults is more problematic than illumination of faults within the sedimentary column. To address these limitations, we make simple modifications to well-established vector attributes including structural dip, azimuth, and amplitude gradients, in combination with variance, and most positive and most negative principal curvature to provide greater interpreter interaction. Using these methods, we can better illuminate fracture “sweet spots” and estimate their intensity and orientation. We apply these methods to better characterize faults in the granite basement of the Cuu Long Basin, Vietnam, and the granite and rhyolite-metarhyolite basement of Osage County, Oklahoma, USA. Cuu Long forms an important unconventional reservoir. In Osage County, we suspect basement control of shallower fractures in the Mississippi chat deposits.

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