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.

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 Three-Dimensional Locating of VHF Broadband Lightning Interferometers

Atmosphere ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 317 ◽  
Author(s):  
Hengyi Liu ◽  
Shi Qiu ◽  
Wansheng Dong
Keyword(s):  
Time Resolution ◽  
High Frequency ◽  
Three Dimensional ◽  
High Time Resolution ◽  
Very High Frequency ◽  
Time Difference Of Arrival ◽  
Lightning Discharges ◽  
Total Lightning ◽  
Locating Information ◽  
Very High

VHF (Very High Frequency) lightning interferometers can locate and observe lightning discharges with a high time resolution. Especially the appearance of continuous interferometers makes the 2-D location of interferometers further improve in time resolution and completeness. However, there is uncertainty in the conclusion obtained by simply analyzing the 2-D locating information. Without the support of other 3-D total lightning locating networks, the 2-station interferometer becomes an option to obtain 3-D information. This paper introduces a 3-D lightning location method of a 2-station broadband interferometer, which uses the theodolite wind measurement method for reference, and gives the simulation results of the location accuracy. Finally, using the multi-baseline continuous 2-D locating method and the 3-D locating method, the locating results of one intra-cloud flash and the statistical results of the initiation heights of 61 cloud-to-ground flashes and 80 intra-cloud flashes are given. The results show that the two-station interferometer has high observation accuracy on both sides of the connection between the two sites. The locating accuracy will deteriorate as the distance between the radiation source and the two stations increases or the height decreases. The actual locating results are similar to those of the existing VHF TDOA (Time Difference of Arrival) lightning locating network.

Effects of aerosol on lightning in Sichuan Basin, Southwest China

2020 ◽  
Author(s):  
Pengguo Zhao
Keyword(s):  
Sichuan Basin ◽  
Reanalysis Data ◽  
Lightning Activity ◽  
Plateau Area ◽  
Significant Difference ◽  
Cloud To Ground Lightning ◽  
The Difference ◽  
Microphysical Processes ◽  
Basin Area ◽  
Very High

<p>The influence of aerosol on lightning is very dependent on environmental factors, including thermal factors, humidity factors, and terrain factors. ADTD cloud-to-ground lightning data, ERA5 reanalysis data, and MERRA2 reanalysis data were applied to discuss the influence of aerosol on lightning activity in Sichuan basin. Thermodynamic factors were the main reasons for the difference in lightning density between the plateau and the basin. The results showed that the influence of aerosol on lightning activity in the basin and the plateau regions showed a significant difference, showing a positive correlation on the plateau and a negative correlation on the basin. In the plateau area, the aerosol concentration was relatively low, and the aerosol stimulated the lightning activity by influencing the microphysical processes. In the basin area, the aerosol load was very high, and the aerosol showed a more significant radiation effect. By reducing the solar radiation reaching the ground, the convective energy on the ground was reduced, and the intensity of lightning activity was finally suppressed.</p>

The 29 June 2000 Supercell Observed during STEPS. Part II: Lightning and Charge Structure

2005 ◽  
Vol 62 (12) ◽  
pp. 4151-4177 ◽  
Author(s):  
Kyle C. Wiens ◽  
Steven A. Rutledge ◽  
Sarah A. Tessendorf
Keyword(s):  
Positive Charge ◽  
Lightning Activity ◽  
Structure Evolution ◽  
Severe Thunderstorm ◽  
Charge Structure ◽  
Flash Rate ◽  
Lightning Detection ◽  
Mapping Array ◽  
Total Lightning ◽  
Mexico Tech

Abstract This second part of a two-part study examines the lightning and charge structure evolution of the 29 June 2000 tornadic supercell observed during the Severe Thunderstorm Electrification and Precipitation Study (STEPS). Data from the National Lightning Detection Network and the New Mexico Tech Lightning Mapping Array (LMA) are used to quantify the total and cloud-to-ground (CG) flash rates. Additionally, the LMA data are used to infer gross charge structure and to determine the origin locations and charge regions involved in the CG flashes. The total flash rate reached nearly 300 min−1 and was well correlated with radar-inferred updraft and graupel echo volumes. Intracloud flashes accounted for 95%–100% of the total lightning activity during any given minute. Nearly 90% of the CG flashes delivered a positive charge to ground (+CGs). The charge structure during the first 20 min of this storm consisted of a midlevel negative charge overlying lower positive charge with no evidence of an upper positive charge. The charge structure in the later (severe) phase was more complex but maintained what could be roughly described as an inverted tripole, dominated by a deep midlevel (5–9 km MSL) region of positive charge. The storm produced only two CG flashes (both positive) in the first 2 h of lightning activity, both of which occurred during a brief surge in updraft and hail production. Frequent +CG flashes began nearly coincident with dramatic increases in storm updraft, hail production, total flash rate, and the formation of an F1 tornado. The +CG flashes tended to cluster in or just downwind of the heaviest precipitation, which usually contained hail. The +CG flashes all originated between 5 and 9 km MSL, centered at 6.8 km (−10°C), and tapped LMA-inferred positive charge both in the precipitation core and (more often) in weaker reflectivity extending downwind. All but one of the −CG flashes originated from >9 km MSL and tended to strike near the precipitation core.

scholarly journals Total Lightning Characteristics Relative to Radar and Satellite Observations of Oklahoma Mesoscale Convective Systems

2013 ◽  
Vol 141 (5) ◽  
pp. 1593-1611 ◽  
Author(s):  
Jeffrey A. Makowski ◽  
Donald R. MacGorman ◽  
Michael I. Biggerstaff ◽  
William H. Beasley
Keyword(s):  
Early Morning ◽  
Mesoscale Convective Systems ◽  
Very High Frequency ◽  
Maximum Area ◽  
Convective Systems ◽  
Lightning Detection ◽  
Mesoscale Convective ◽  
Total Lightning ◽  
Cloud Tops ◽  
Mapping Arrays

Abstract The advent of regional very high frequency (VHF) Lightning Mapping Arrays (LMAs) makes it possible to begin analyzing trends in total lightning characteristics in ensembles of mesoscale convective systems (MCSs). Flash initiations observed by the Oklahoma LMA and ground strikes observed by the National Lightning Detection Network were surveyed relative to infrared satellite and base-scan radar reflectivity imagery for 30 mesoscale convective systems occurring over a 7-yr period. Total lightning data were available for only part of the life cycle of most MCSs, but well-defined peaks in flash rates were usually observed for MCSs having longer periods of data. The mean of the maximum 10-min flash rates for the ensemble of MCSs was 203 min−1 for total flashes and 41 min−1 for cloud-to-ground flashes (CGs). In total, 21% of flashes were CGs and 13% of CGs lowered positive charge to ground. MCSs with the largest maximum flash rates entered Oklahoma in the evening before midnight. All three MCSs entering Oklahoma in early morning after sunrise had among the smallest maximum flash rates. Flash initiations were concentrated in or near regions of larger reflectivity and colder cloud tops. The CG flash rates and total flash rates frequently evolved similarly, although the fraction of flashes striking ground usually increased as an MCS decayed. Total flash rates tended to peak approximately 90 min before the maximum area of the −52°C cloud shield, but closer in time to the maximum area of colder cloud shields. MCSs whose −52°C cloud shield grew faster tended to have larger flash rates.

scholarly journals Enhancement of Cloud-to-Ground Lightning Activity Caused by the Urban Effect: A Case Study in the Beijing Metropolitan Area

2021 ◽  
Vol 13 (7) ◽  
pp. 1228
Author(s):  
Yongping Wang ◽  
Gaopeng Lu ◽  
Tao Shi ◽  
Ming Ma ◽  
Baoyou Zhu ◽  
...  
Keyword(s):  
Metropolitan Area ◽  
Industrial Area ◽  
Lightning Activity ◽  
Beijing Area ◽  
Factors Affecting ◽  
Pollutant Concentrations ◽  
Lightning Detection ◽  
Cloud To Ground Lightning ◽  
Beijing Metropolitan Area ◽  
Cg Lightning

To investigate the possible impact of urban development on lightning activity, an eight-year (2010–2017) cloud-to-ground (CG) lightning dataset provided by the National-Wide Lightning Detection Network in China was analyzed to characterize the CG lightning activity in the metropolitan area of Beijing. There is a high CG flash density area over the downtown of Beijing, but different from previous studies, the downwind area of Beijing is not significantly enhanced. Compared with the upwind area, the CG flash density in the downtown area was enhanced by about 50%. Negative CG flashes mainly occurred in the downtown and industrial area, while positive CG flashes were distributed evenly. The percentage of positive CG flashes with Ipeak ≥ 75 kA is more than six times that of the corresponding negative CG flashes in the Beijing area. The enhancement of lightning activity varies with season and time. About 98% of CG flashes occurred from May to September, and the peak of CG diurnal variation is from 1900 to 2100 local time. Based on the analysis of thunderstorm types in Beijing, it is considered that the abnormal lightning activity is mainly responsible for an enhancement of the discharge number in frontal systems rather than the increase of the number of local thunderstorms. In addition, there is a non-linear relationship between pollutant concentrations and CG flash number, which indicates that there are other critical factors affecting the production of lightning.

Summertime Cloud-to-Ground Lightning Activity around Major Midwestern Urban Areas

1995 ◽  
Vol 34 (7) ◽  
pp. 1633-1642 ◽  
Author(s):  
Nancy E. Westcott
Keyword(s):  
Urban Areas ◽  
Cloud Condensation Nuclei ◽  
Thunderstorm Activity ◽  
Lightning Activity ◽  
Lightning Flash ◽  
Storm Activity ◽  
Topographic Features ◽  
Activity Frequency ◽  
Lightning Detection ◽  
Cloud To Ground Lightning

Abstract Cloud-to-ground lightning flash data collected by the National Lightning Detection Network were analysed in and around 16 central U.S. cities for the period 1989–92. Lightning data are well suited to study storm activity in and around large urban areas since their continuity and coverage in space and time is superior to historical, spatially limited records of thunderstorm activity. Frequency of cloud-to-ground lightning flashes (of negative and positive polarity) in the area immediately upwind, within, and immediately downwind of the cities were compared. An enhancement of lightning frequency on the order of 40%–85% was found over and downwind of many of these cities. A number of possible urban-related causal factors were examined including effects of increased urban concentrations of cloud condensation nuclei, urban population and size, and the presence of distinct topographic features in and around the cities. Various factors, physical and anthropogenic, appeared to interact in diverse ways to account for changes in lightning flash frequency. The enhancement of lightning activity was largest during the afternoon hours when the urban–rural temperature differences are usually smallest, but when the atmosphere is generally the most unstable and when there is often a maximum in convective activity. The spatial distribution of the first 50 lightning flashes from each storm suggested that the urban area did not initiate new lightning storms. Thus, the overall results suggested that existing thunderstorms were the most strongly affected.

scholarly journals Cloud-to-ground lightning over Mexico and adjacent oceanic regions: a preliminary climatology using the WWLLN dataset

2010 ◽  
Vol 28 (11) ◽  
pp. 2047-2057 ◽  
Author(s):  
B. Kucieńska ◽  
G. B. Raga ◽  
O. Rodríguez
Keyword(s):  
Gulf Of Mexico ◽  
Seasonal Cycle ◽  
Tropical Pacific ◽  
Seasonal Distribution ◽  
Lightning Activity ◽  
Inter Tropical Convergence Zone ◽  
Diurnal Distribution ◽  
Cloud To Ground Lightning ◽  
The Caribbean ◽  
Very High

Abstract. This work constitutes the first climatological study of lightning over Mexico and adjacent oceanic areas for the period 2005–2009. Spatial and temporal distributions of cloud to ground lightning are presented and the processes that contribute to the lightning variability are analysed. The data are retrieved from the World Wide Lightning Location Network (WWLLN) dataset. The current WWLL network includes 40 stations which cover much of the globe and detect very low frequency radiation ("spherics") associated with lightning. The spatial distribution of the average yearly lightning over the continental region of Mexico shows the influence of orographic forcing in producing convective clouds with high lightning activity. However, a very high number of strikes is also observed in the States of Tabasco and Campeche, which are low-lying areas. This maximum is related to the climatological maximum of precipitation for the country and it may be associated with a region of persistent low-level convergence and convection in the southern portion of the Gulf of Mexico. The maps of correlation between rainfall and lightning provide insight into the microphysical processes occurring within the clouds. The maritime clouds close to the coastline exhibit similar properties to continental clouds as they produce very high lightning activity. The seasonal cycle of lightning registered by WWLLN is consistent with the LIS/OTD dataset for the selected regions. In terms of the annual distribution of cloud-to-ground strikes, July, August and September exhibit the highest number of strikes over continental Mexico. The diurnal cycle indicates that the maximum number of strikes over the continent is observed between 6 and 9 p.m. LT. The surrounding oceanic regions were subdivided into four distinct sectors: Gulf of Mexico, Caribbean, Sub-tropical Pacific and Tropical Pacific. The Gulf of Mexico has the broadest seasonal distribution, since during winter lightning associated with mid-latitude systems also affects the region. The diurnal distribution of lightning for the Gulf of Mexico exhibits the highest number of strokes at 9 a.m. The Caribbean seasonal distribution is slightly biased towards early fall, with a clear maximum observed during October. The diurnal distribution of lightning over the Caribbean is quite uniform with a slight increase near midnight. The Subtropical Pacific has the narrowest seasonal distribution, associated with the convection observed during the "North American Monsoon", with the maximum number of strikes during August and September. In contrast, the Tropical Pacific has a broader seasonal cycle, associated with convection in the Inter-Tropical Convergence Zone (ITCZ), starting in May and lasting till October. In both adjacent Pacific regions, the strikes present a maximum in the early morning, the time of the highest frequency of land breeze.

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.

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

2007 ◽  
Vol 25 (10) ◽  
pp. 2113-2118 ◽  
Author(s):  
S. K. Kar ◽  
Y.-A. Liou ◽  
K.-J. Ha
Keyword(s):  
South Korea ◽  
Correlation Coefficients ◽  
Lightning Activity ◽  
Lightning Flash ◽  
Urban Effect ◽  
Percentage Decrease ◽  
Lightning Detection ◽  
Cloud To Ground Lightning ◽  
The City ◽  
Cg Lightning

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

Sign in / Sign up

Export Citation Format

Share Document