scholarly journals A Cloud-to-Ground Lightning Climatology for Romania

2010 ◽  
Vol 138 (2) ◽  
pp. 579-591 ◽  
Author(s):  
Bogdan Antonescu ◽  
Sorin Burcea
Keyword(s):  
Convergence Zone ◽  
Spatial Analyses ◽  
Monthly Variation ◽  
Lightning Detection ◽  
Positive Currents ◽  
Cloud To Ground Lightning ◽  
Monthly Distribution ◽  
The Mean ◽  
Positive Peak ◽  
Cg Lightning

Abstract The first study of the characteristics of cloud-to-ground (CG) lightning in Romania, based on the data recorded by the Romanian National Lightning Detection Network (RNLDN), is presented. The data, more than 1.75 million CG flashes, covers the entirety of Romania and were recorded between January 2003 and December 2005 and January and December 2007. The spatial analyses (total and positive flash density, the percentage of positive flashes, and negative and positive peak currents) were done with a resolution of 20 km. The average spatial distribution shows a maximum (3.06 flashes km−2 yr−1) over the south slopes of the central meridional Carpathians possibly associated with the Romanian Plain convergence zone. The mean monthly variation shows maximum CG lightning between May and September (98%) and minimum values in December and January. High values (>0.028 km−2 yr−1) for positive CG lightning density are observed in southwestern and central Romania. The monthly distribution of positive flashes shows a main maximum in May (25%) and a secondary maximum in August (23%), suggesting that positive flashes tend to occur earlier in the year than total flashes. The mean annual percentage of positive flashes has lower values at 1.3% in the central parts of the country. The percentage of positive CG flashes changes over the year from 1% in June to 19% in January. The monthly variation of the median first-strike peak currents has a maximum in winter and reaches a minimum in July, for both negative and positive currents. The mean diurnal cycle for total CG lightning flashes peaks between 1230 and 1430 UTC (2.2%) and shows a minimum between 0600 and 0800 UTC (0.3%).

scholarly journals A Cloud-to-Ground Lightning Climatology for Poland

2015 ◽  
Vol 143 (11) ◽  
pp. 4285-4304 ◽  
Author(s):  
Mateusz Taszarek ◽  
Bartosz Czernecki ◽  
Aneta Kozioł
Keyword(s):  
Annual Number ◽  
Lightning Flash ◽  
Grid Cells ◽  
Lake District ◽  
Negative Current ◽  
Lightning Detection ◽  
Cloud To Ground Lightning ◽  
The Mean ◽  
The Baltic ◽  
Cg Lightning

Abstract This research focuses on the climatology of cloud-to-ground (CG) lightning flashes based on PERUN lightning detection network data from 2002 to 2013. To present various CG lightning flash characteristics, 10 km × 10 km grid cells are used, while for estimating thunderstorm days, circles with radii of 17.5 km in the 1 km × 1 km grid cells are used. A total of 4 328 892 CG lightning flashes are used to analyze counts, density, polarity, peak current, and thunderstorm days. An average of 151 days with thunderstorm (appearing anywhere in Poland) occurs each year. The annual number of days with thunderstorms increases southeasterly from the coast of the Baltic Sea (15–20 days) to the Carpathian Mountains (30–35 days). The mean CG lightning flash density varies from 0.2 to 3.1 flashes km−2 yr−1 with the highest values in the southwest–northeast belt from Kraków-Częstochowa Upland to the Masurian Lake District. The maximum daily CG lightning flash density in this region amounted to 9.1 km−2 day−1 (3 July 2012). The monthly variation shows a well-defined thunderstorm season extending from May to August with July as the peak month. The vast majority of CG lightning flashes were detected during the daytime (85%) with a peak at 1400 UTC and a minimum at 0700 UTC. Almost 97% of all CG lightning flashes in the present study had a negative current, reaching the highest average monthly values in February (55 kA) and the lowest in July (24 kA). The percentage of positive CG lightning flashes was the lowest during the summer (2%–3%) and the highest during the winter (10%–20%).

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 The North American Lightning Detection Network (NALDN)—Analysis of Flash Data: 2001–09

2011 ◽  
Vol 139 (5) ◽  
pp. 1305-1322 ◽  
Author(s):  
Richard E. Orville ◽  
Gary R. Huffines ◽  
William R. Burrows ◽  
Kenneth L. Cummins
Keyword(s):  
United States ◽  
North America ◽  
North American ◽  
The United States ◽  
The North ◽  
Lightning Detection ◽  
Geographical Regions ◽  
Positive Peak ◽  
The U.S ◽  
Cg Lightning

Cloud-to-ground (CG) lightning data have been analyzed for the years 2001–09 for North America, which includes Alaska, Canada, and the lower 48 U.S. states. Flashes recorded within the North American Lightning Detection Network (NALDN) are examined. No corrections for detection efficiency variability are made over the 9 yr of the dataset or over the large geographical area comprising North America. There were network changes in the NALDN during the 9 yr, but these changes have not been corrected for nor have the recorded data been altered in any way with the exception that all positive lightning reports with peak currents less than 15 kA have been deleted. Thus, the reader should be aware that secular changes are not just climatological in nature. All data were analyzed with a spatial resolution of 20 km. The analyses presented in this work provide a synoptic view of the interannual variability of lightning observations in North America, including the impacts of physical changes in the network during the 9 yr of study. These data complement and extend previous analyses that evaluate the U.S. NLDN during periods of upgrade. The total (negative and positive) flashes for ground flash density, the percentage of positive lightning, and the positive flash density have been analyzed. Furthermore, the negative and positive first stroke peak currents and the flash multiplicity have been examined. The highest flash densities in Canada are along the U.S.–Canadian border (1–2 flashes per square kilometer) and in the United States along the Gulf of Mexico coast from Texas through Florida (exceeding 14 flashes per square kilometer in Florida). The Gulf Stream is “outlined” by higher flash densities off the east coast of the United States. Maximum annual positive flash densities in Canada range primarily from 0.01 to 0.3 flashes per square kilometer, and in the United States to over 0.5 flashes per square kilometer in the Midwest and in the states of Louisiana and Mississippi. The annual percentage of positive lightning to ground varies from less than 2% over Florida to values exceeding 25% off the West Coast, Alaska, and the Yukon. A localized maximum in the percentage of positive lightning in the NALDN occurs in Manitoba and western Ontario, just north of North Dakota and Minnesota. When averaged over North America, first stroke negative median peak currents range from 19.8 kA in 2001 to 16.0 kA in 2009 and for all years, average 16.1 kA. First stroke positive median peak currents range from a high of 29.0 kA in 2008 and 2009 to a low of 23.3 kA in 2003 with a median of 25.7 kA for all years. There is a relatively sharp transition from low to high median negative peak currents along the Gulf and Atlantic coasts of the United States. No sharp transitions are observed for the median positive peak currents. Relatively lower positive peak currents occur throughout the southeastern United States. The highest values of mean negative multiplicity exceed 3.0 strokes per flash in the NALDN with some variation over the 9 yr. Lower values of mean negative multiplicity occur in the western United States. Positive flash mean multiplicity is slightly higher than 1.1, with the highest values of 1.7 observed in the southwestern states. As has been noted in prior research, CG lightning has significant variations from storm to storm as well as between geographical regions and/or seasons and, consequently, a single distribution for any lightning parameter, such as multiplicity or peak current, may not be sufficient to represent or describe the parameter.

A Research on the Characteristics of Lightning in Hailstorms of Beijing Area by the Method of Analysis the Lightning Detection Data and Numerical Simulation

2013 ◽  
Vol 416-417 ◽  
pp. 1993-1996
Author(s):  
Chuang Chuang Zhang ◽  
Ming Ma
Keyword(s):  
Numerical Simulation ◽  
Numerical Model ◽  
Two Dimensional ◽  
Beijing Area ◽  
Variation Trend ◽  
Lightning Detection ◽  
The Mean ◽  
Total Lightning ◽  
The Relationship ◽  
Cg Lightning

In this paper, by using lightning detection material of Beijing area, we analyzing the characteristics of lightning in four hailstorms. The results show that the mean percentage of cloud-to-ground (CG) lightning accounting for the total lightning is 8.28%, which is lower than the normal thunderstorms. On the contrary, the CG lightning has a higher proportion of positive CG than the normal thunderstorms. All cases variation trend of lightning frequency show a conspicuous intensive increase before the hail reaches the ground. The peak lightning frequency usually occurs 5 to 80min earlier than hailstone falling. These characteristics may have contribution to the forecasting of hailstorms of Beijing area. Another work was done by using a two-dimensional numerical model which includes dynamic, microphysics, electrification and discharge to simulate these four instances. The results present similar characteristics with the actual detection data. This will lay a foundation for the continuing studies of the relationship between hailstorm and lightning and the inherent reason of the relationship by using the method of numerical simulation.

scholarly journals Cloud-to-Ground Lightning Flash Parameters Associated with Heavy Rainfall Alarms in the Denver, Colorado, Urban Drainage and Flood Control District ALERT Network

2006 ◽  
Vol 134 (9) ◽  
pp. 2566-2580 ◽  
Author(s):  
S. Jeffrey Underwood
Keyword(s):  
Heavy Rainfall ◽  
Flood Control ◽  
Rainfall Rate ◽  
Urban Drainage ◽  
Lightning Flash ◽  
Flash Duration ◽  
Lower Elevation ◽  
Lightning Detection ◽  
Cloud To Ground Lightning ◽  
The Mean

Abstract Rainfall data from the Denver, Colorado, Urban Drainage and Flood Control District Automated Local Evaluation in Real Time (ALERT) network were used to identify heavy rainfall alarms for the period 1999–2003. Twenty-nine heavy rainfall-rate alarms were identified. Cloud-to-ground (CG) lightning flash data from the National Lightning Detection Network (NLDN) were analyzed for the 90 min prior to each heavy rainfall alarm. Spatial patterns from NLDN data were extracted using a point-polygon topology developed with basic Geographic Information System procedures. The information extracted from the polygons was used to calculated summary statistics for rainfall rates, CG flash rates, and CG flash duration. Heavy rainfall episodes were divided into two groups based on latitude, longitude, and elevation. Heavy rainfall episodes in the higher elevations of the study area produced an average of 29 mm of rainfall per episode and 1095 CG flashes in the 90 min prior to the rainfall-rate alarm. Only five polygons, all closely proximal to the alarm sites, produced significant CG flash rates prior to the rainfall alarms, and areas with CG flash durations greater than 25 min were clustered near the rainfall-rate alarm sites. In the second group (the lower elevation stations) the mean event produced a total of 33 mm of rainfall and 1182 CG flashes during the 90 min prior to the rainfall alarm. Four polygons saw consistent CG flash rates in the 90 min prior to the heavy rainfall alarms and CG flash duration was at its greatest in areas just west of the ALERT stations.

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.

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.

scholarly journals Relação Entre o Total de Raios e os Raios Nuvem-Solo Sobre o Leste da Amazônia

2020 ◽  
Vol 13 (2) ◽  
pp. 782
Author(s):  
Giordani Rafael Conceição Sodré ◽  
Douglas Batista da Silva Ferreira ◽  
Juarez Oliveira Ventura ◽  
Cláudia Priscila Wanzeler Costa ◽  
Everaldo Barreiros Souza ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Satellite Remote Sensing ◽  
Pearson Correlation ◽  
Surface Type ◽  
First Semester ◽  
Cloud To Ground Lightning ◽  
Lightning Location System ◽  
The Mean ◽  
Total Lightning ◽  
Cg Lightning

Neste estudo foi realizada uma análise comparativa da ocorrência de raios do tipo nuvem-solo (NS), medidos por sensores em superfície e o total de raios (NS e intra-nuvem - IN), derivados de sensoriamento remoto por satélite, objetivando estabelecer uma proporção dos raios NS entre ambos os Lightning Location System (LLS) para o leste da Amazônia. Foram utilizados dados da STARNET e do banco de dados LRTMS (OTD/LIS). A metodologia de análise consistiu no cálculo da Razão Z, da Proporção de Incidência de Raios NS e da Correlação de Pearson. Adicionalmente também foi realizada uma investigação sobre a relação da quantidade de raios NS em função da altitude do relevo. Os resultados apontaram que a incidência de raios NS tem uma oscilação média mensal de 7,5% a 20,4% do total de raios medidos por sensoriamento remoto e a quantidade varia de acordo com o tipo de superfície, sendo que na região oceânica observou-se baixa incidência de raios NS, nas regiões mais próximas ao litoral observou-se no primeiro semestre os maiores valores da proporção de incidência de raios NS, enquanto que no interior do continente, o máximo de atividade elétrica do tipo nuvem-solo apresenta maiores percentuais durante o segundo semestre. Também foi constatado que o relevo não altera a proporção de incidência dos raios NS, uma vez que não foi encontrada uma relação direta somente com a altura do relevo. Relationship Between Total Lightning and Cloud-To-Ground Lightning in Eastern AmazoniaA B S T R A C TAn analysis of the occurrence of cloud-to-ground (CG) lightning, measured by ground-based sensors, and total lightning (CG and intra-cloud (IC) lightning), detected by satellite remote sensing, was performed in this study to compare the proportion of CG lightning between the two lightning location systems (LLS) in Eastern Amazonia. STARNET and LRTMS (OTD/LIS) data were used. The method of analysis consisted of calculating the Z ratio, the proportion of incidence of CG lightning and the Pearson correlation coefficient. Furthermore, the variation in the number of CG lightning flashes as a function of terrain altitude was also investigated. The results indicated that the mean monthly CG lightning incidence ranges from 7.5% to 20.4% of the total lightning measured by remote sensing and that the number of CG lightning flashes varies according to surface type. More specifically, the oceanic region showed low CG lightning incidence, with the regions closest to the coast having the highest proportion of CG lightning incidence in the first semester; in contrast, the CG electrical activity peaked inland during the second semester. The results also showed that the terrain had no effect on the proportion of CG lightning incidence because no direct relationship with terrain height alone was found.Keywords: Proportion, Z Ratio, Terrain Altitude.

scholarly journals COMPARISON TWO LOCATIONS OF LIGHTNING DETECTION

2019 ◽  
Vol 5 (2) ◽  
pp. 1-9
Author(s):  
Deni Septiadi ◽  
Hadi Suntoko ◽  
Anton Widodo ◽  
Riza Arian Noor
Keyword(s):  
Real Time ◽  
Detection Efficiency ◽  
Low Frequency ◽  
Target Area ◽  
Location Error ◽  
Lightning Detection ◽  
Radio Signals ◽  
Cloud To Ground Lightning ◽  
Cg Lightning

The objective of this study was to identify the lightning distribution by comparing of two lightning sensors located in Jakarta and Bandung. Using Storm Tracker Lightning Detector maintained by the Indonesia Agency for Meteorology, Climatology and Geophysics (BMKG), Cloud-to-Ground lightning (CG) analyzed with a various radius i.e. 0.1˚, 0.5˚ and 1.0˚. Storm Tracker Lightning Detector consists of an antenna connected to the PCI card and able to detect Low Frequency (LF) of radio signals generated by lightning (10 KHz to 200 KHz). The data used are based on the available records of near real time 15 minutes CG lightning data. This study aims at revealing ideally possible location of the lightning sensor to optimize lightning detection. For further analysis, the distribution of the CG lightning estimated in the target area located about the middle between Jakarta and Bandung. The analysis of lightning described by calculating the detection efficiency of lightning sensor and the analysis of lightning location error.

scholarly journals A cloud-to-ground lightning climatology for north-eastern Italy

2013 ◽  
Vol 10 (1) ◽  
pp. 77-84 ◽  
Author(s):  
L. Feudale ◽  
A. Manzato ◽  
S. Micheletti
Keyword(s):  
Spatial Distribution ◽  
Eastern Alps ◽  
Spatial Density ◽  
North East ◽  
The North ◽  
Lightning Detection ◽  
North Eastern ◽  
Cloud To Ground Lightning ◽  
The Mean ◽  
Southern Flank

Abstract. This study analyzes the spatial distribution and temporal characteristics of cloud-to-ground lightnings (C2G) in the North East of Italy and the neighboring areas of Austria, Slovenia and Croatia. The dataset consists of about 6.5 millions C2G flash records, both positive and negative, observed between January 1995 and December 2011 by the "Centro Elettrotecnico Sperimentale Italiano-Sistema Italiano Rilevamento Fulmini'' (CESI/SIRF), part of the European Cooperation for Lightning Detection (EUCLID) Network. The results show that C2G lightnings concentrate in the foothill regions on the southern flank of the Eastern Alps with a maximum of discharge frequency of 10 lightnings per km2 per year. The number of C2G strokes varies with the period of the year: the most active period for lightning starts in April and lasts through November with the highest number of C2G strokes happening during the summer months of July and August, with maximum spatial density slightly moving from the mountain to the coastal area. The least frequency of C2G strokes is observed during wintertime. The mean diurnal C2G lightning activity for the whole domain shows a peak around 16:00–17:00 UTC and reaches a minimum around 07:00–09:00 UTC; the mean spatial distribution follows different patterns depending on the period of the day.

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