scholarly journals Location accuracy of VLF World-Wide Lightning Location (WWLL) network: Post-algorithm upgrade

2005 ◽  
Vol 23 (2) ◽  
pp. 277-290 ◽  
Author(s):  
C. J. Rodger ◽  
J. B. Brundell ◽  
R. L. Dowden
Keyword(s):  
Real Time ◽  
World Wide ◽  
Detection Efficiency ◽  
Activity Levels ◽  
Operational Mode ◽  
Current Form ◽  
Location Accuracy ◽  
Central Processing ◽  
Lightning Discharges ◽  
Total Lightning

Abstract. An experimental VLF World-Wide Lightning Location (WWLL) network has been developed through collaborations with research institutions across the globe. The aim of the WWLL is to provide global real-time locations of lightning discharges, with >50% CG flash detection efficiency and mean location accuracy of <10km. While these goals are essentially arbitrary, they do define a point where the WWLL network development can be judged a success, providing a breakpoint for a more stable operational mode. The current network includes 18 stations which cover much of the globe. As part of the initial testing phase of the WWLL the network operated in a simple mode, sending the station trigger times into a central processing point rather than making use of the sferic Time of Group Arrival (TOGA). In this paper the location accuracy of the post-TOGA algorithm WWLL network (after 1 August 2003) is characterised, providing estimates of the globally varying location accuracy for this network configuration which range over 1.9-19km, with the global median being 2.9km, and the global mean 3.4km. The introduction of the TOGA algorithm has significantly improved the location accuracies. The detection efficiency of the WWLL is also considered. In the selected region the WWLL detected ~13% of the total lightning, suggesting a ~26% CG detection efficiency and a ~10% IC detection efficiency. Based on a comparison between all WWLL good lightning locations in February-April 2004, and the activity levels expected from satellite observations we estimate that the WWLL is currently detecting ~2% of the global total lightning, providing good locations for ~5% of global CG activity. The existing WWLL network is capable of providing real-time positions of global thunderstorm locations in its current form.

scholarly journals Detection efficiency of the VLF World-Wide Lightning Location Network (WWLLN): initial case study

2006 ◽  
Vol 24 (12) ◽  
pp. 3197-3214 ◽  
Author(s):  
C. J. Rodger ◽  
S. Werner ◽  
J. B. Brundell ◽  
E. H. Lay ◽  
N. R. Thomson ◽  
...  
Keyword(s):  
World Wide ◽  
Detection Efficiency ◽  
Low Frequency ◽  
High Peak ◽  
Global Network ◽  
Theoretical Modelling ◽  
Return Stroke ◽  
Peak Current ◽  
Location Data ◽  
Lightning Discharges

Abstract. An experimental Very Low Frequency (VLF) World-Wide Lightning Location Network (WWLLN) has been developed through collaborations with research institutions across the world, providing global real-time locations of lightning discharges. As of April 2006, the network included 25 stations providing coverage for much of the Earth. In this paper we examine the detection efficiency of the WWLLN by comparing the locations from this network with lightning location data purchased from a commercial lightning location network operating in New Zealand. Our analysis confirms that WWLLN favours high peak current return stroke lightning discharges, and that discharges with larger currents are observed by more stations across the global network. We then construct a first principles detection efficiency model to describe the WWLLN, combining calibration information for each station with theoretical modelling to describe the expected amplitudes of the VLF sferics observed by the network. This detection efficiency model allows the prediction of the global variation in WWLLN lightning detection, and an estimate of the minimum CG return stroke peak current required to trigger the network. There are strong spatial variations across the globe, primarily due to station density and sensitivity. The WWLLN is currently best suited to study the occurrence and impacts of high peak-current lightning. For example, in 2005 about 12% of the global elve-producing lightning will have been located by the network. Since the lightning-EMP which produce elves has a high mean rate (210 per minute) it has the potential to significantly influence the ionosphere on regional scales.

scholarly journals A Performance Evaluation of the World Wide Lightning Location Network (WWLLN) over the Tibetan Plateau

2018 ◽  
Vol 35 (4) ◽  
pp. 927-939 ◽  
Author(s):  
Penglei Fan ◽  
Dong Zheng ◽  
Yijun Zhang ◽  
Shanqiang Gu ◽  
Wenjuan Zhang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
World Wide ◽  
Detection Efficiency ◽  
Tropical Rainfall Measuring Mission ◽  
Spatial Location ◽  
Systematic Evaluation ◽  
The Tibetan Plateau ◽  
The World ◽  
Total Lightning ◽  
Cg Lightning

AbstractA systematic evaluation of the performance of the World Wide Lightning Location Network (WWLLN) over the Tibetan Plateau is conducted using data from the Cloud-to-Ground Lightning Location System (CGLLS) developed by the State Grid Corporation of China for 2013–15 and lightning data from the satellite-based Tropical Rainfall Measuring Mission (TRMM) Lightning Imaging Sensor (LIS) for 2014–15. The average spatial location separation magnitudes in the midsouthern Tibetan Plateau (MSTP) region between matched WWLLN and CGLLS strokes and over the whole Tibetan Plateau between matched WWLLN and LIS flashes were 9.97 and 10.93 km, respectively. The detection efficiency (DE) of the WWLLN rose markedly with increasing stroke peak current, and the mean stroke peak currents of positive and negative cloud-to-ground (CG) lightning detected by the WWLLN in the MSTP region were 62.43 and −56.74 kA, respectively. The duration, area, and radiance of the LIS flashes that were also detected by the WWLLN were 1.27, 2.65, and 4.38 times those not detected by the WWLLN. The DE of the WWLLN in the MSTP region was 9.37% for CG lightning and 2.58% for total lightning. Over the Tibetan Plateau, the DE of the WWLLN for total lightning was 2.03%. In the MSTP region, the CG flash data made up 71.98% of all WWLLN flash data. Based on the abovementioned results, the ratio of intracloud (IC) lightning to CG lightning in the MSTP region was estimated to be 4.05.

scholarly journals Applications of Nano-Rkin Internet of Things (Iot)

2020 ◽  
Vol 9 (4S2) ◽  
pp. 53-59
Keyword(s):  
World Wide Web ◽  
Internet Of Things ◽  
Real Time ◽  
World Wide ◽  
Electrical Power ◽  
Battery Life ◽  
Sleep Mode ◽  
Processing Unit ◽  
Central Processing ◽  
Community Facilities

Internet of Things (IoT) is notoriously described as World wide web of objectives as ‘Things’ is a global and interconnected communicate for whatever easily interchange information through Internet sensing systems. The tiny wsn devices are actually having qualities like low energy capability, less weight minimal battery support managed through Real-time operating systems. [6]. Nano-RK is open source and having to work on real-time tasks. The Nano-RK according reserve reservations tasks known other name as resource kernel. A source little bit uses reservations on specifically just how typically device information could be consumed as well as handled. For example, using resource reservations concept, create Central Processing Unit resource appointments present day innovation, a task might just be actually enabled to carry out 10 ms every 150 ms. Likewise one more case through making use of Nano-RK by using System source reservations innovation a node could merely be enabled to transfer 10 network packages every moment. The utilizing these bookings to secure electric battery lifestyle of a node along with likewise protecting a fallen short node from making too much messages in system internet network scenario. According this, the energy capability of a battery life of a node are going to definitely be actually reduced. The Nano-RK is open resource as well as additionally support in programming language like C and C++. Nano-RK can operates on the Atmel-based FireFly platform. The target of this paper is an intro importance of features and applications an intro of Nano-RK. Depending on to running device capacities as well as additionally qualities as well as an open resource of ecological community facilities, the Nano-RK is the a suited operating system os for tightened as well as minimized electrical power sensing unit resources for World wide web of connected things. By particular study, the research study of one of the most crucial functions of IOT enable Nano-Rk located Reservations Booking, Deep-in sleep mode environment, Error administration and likewise pointing characteristics of Nano-RK os. [3].

scholarly journals Location accuracy of long distance VLF lightning locationnetwork

2004 ◽  
Vol 22 (3) ◽  
pp. 747-758 ◽  
Author(s):  
C. J. Rodger ◽  
J. B. Brundell ◽  
R. L. Dowden ◽  
N. R. Thomson
Keyword(s):  
Atmospheric Electricity ◽  
Random Errors ◽  
Long Distance ◽  
Worst Case ◽  
Location Accuracy ◽  
Central Processing ◽  
Location Data ◽  
Initial Stage ◽  
Lightning Discharges ◽  
The Difference

Abstract. An experimental VLF WorldWide Lightning Location (WWLL) network is being developed to provide realtime locations of cloud to ground lightning discharges occurring throughout the globe. This network has expanded from a limited number of stations in the Western Pacific to its current state of 11 stations, in most longitude sectors, with additional stations planned in the near future. As part of the initial testing phase of the WWLL the network has operated in a simple mode, sending the station trigger times into a central processing point rather than using the sferic Time of Group Arrival (TOGA). During this initial stage, a significant quantity of lightning location data has been collected, some of which is being applied to research questions. In this paper the operation of the WWLL network is described, and the location accuracy of the pre-TOGA WWLL network is characterised. This is performed by contrasting commercial lightning location data from an Australian network, Kattron, over 2 days in January 2002, with 4 WWLL stations covering the same region. It was found that there were 426 matched lightning events, corresponding to lightning discharges with large lightning return stroke peak currents (mean absolute peak current of ~26kA compared with ~12kA for all Kattron events). By considering the random errors in the difference locations between the matching lightning events, an appropriate Gaussian timing error for the WWLL network of receiving stations is determined, and hence an estimate for the global location errors for the existing 11-station network is found. The "worst-case" global location error for the existing network ranges spatially from 7.5–100km, with the global median being 15km, and the global mean 30km. When the TOGA method is implemented, the station timing errors will decrease, allowing for an increase in the location accuracies. Hence, the location accuracy estimates determined in this paper will be very conservative for the future WWLL network employing the TOGA technique. Key words. Meteorology and atmospheric dynamics (lightning, atmospheric electricity, instruments and techniques)

scholarly journals Evaluation of Fengyun-4A Lightning Mapping Imager (LMI) Performance during Multiple Convective Episodes over Beijing

2021 ◽  
Vol 13 (9) ◽  
pp. 1746
Author(s):  
Zhixiong Chen ◽  
Xiushu Qie ◽  
Juanzhen Sun ◽  
Xian Xiao ◽  
Yuxin Zhang ◽  
...  
Keyword(s):  
Doppler Radar ◽  
Detection Efficiency ◽  
Ground Truth ◽  
Radar Data ◽  
Detection Capability ◽  
Cloud Properties ◽  
Order Of Magnitude ◽  
Total Lightning ◽  
Matching Criteria ◽  
Event Based

This study investigates the characteristics of space-borne Lightning Mapping Imager (LMI) lightning products and their relationships with cloud properties using ground-based total lightning observations from the Beijing Broadband Lightning Network (BLNET) and cloud information from S-band Doppler radar data. LMI showed generally consistent lightning spatial distributions with those of BLNET, and yielded a considerable lightning detection capability over regions with complex terrain. The ratios between the LMI events, groups and flashes were approximately 9:3:1, and the number of LMI-detected flashes was roughly one order of magnitude smaller than the number of BLNET-detected flashes. However, in different convective episodes, the LMI detection capability was likely to be affected by cloud properties, especially in strongly electrified convective episodes associated with frequent lightning discharging and thick cloud depth. As a result, LMI tended to detect lightning flashes located in weaker and shallower cloud portions associated with fewer cloud shielding effects. With reference to the BLNET total lightning data as the ground truth of observation (both intra-cloud lightning and cloud-to-ground lightning flashes), the LMI event-based detection efficiency (DE) was estimated to reach 28% under rational spatiotemporal matching criteria (1.5 s and 65 km) over Beijing. In terms of LMI flash-based DE, it was much reduced compared with event-based DE. The LMI flash-based ranged between 1.5% and 3.5% with 1.5 s and 35–65 km matching scales. For 330 ms and 35 km, the spatiotemporal matching criteria used to evaluate Geostationary Lightning Mapper (GLM), the LMI flash-based DE was smaller (<1%).

Measurement of a World-Wide Transfer Function for Marine Cloud Brightening

2021 ◽  
Vol 6 (3) ◽  
Author(s):  
Salter SH ◽  
Keyword(s):  
Transfer Function ◽  
Real Time ◽  
World Wide ◽  
Climate Model ◽  
Sea Water ◽  
Cloud Condensation Nuclei ◽  
Short Life ◽  
Weather Patterns ◽  
Weather Observations ◽  
The World

Marine cloud brightening with a sub-micron spray of filtered sea water can exploit the Twomey effect to enhance planetary cooling. Several previous climate model results show that it can also affect precipitation in both directions in different places. Modulating the climate model settings for the concentration of cloud condensation nuclei with separate coded sequences in a number of spray regions round the world and correlating each sequence with the resulting weather patterns in observing stations round the world can give an everywhereto- everywhere transfer function of spray from each region to each observing station. The short life of spray allows the best choices of spray regions and seasons. Spray patterns can be modified tactically to suit real-time weather observations.

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.

scholarly journals Electrical characteristics and environmental conditions of lightning-ignited fires in the Iberian Peninsula and Mediterranean France between 2009 and 2015

2020 ◽  
Author(s):  
Francisco J. Pérez-Invernón ◽  
Heidi Huntrieser ◽  
Sergio Soler Lopez ◽  
Francisco J. Gordillo-Vázquez ◽  
Javier Navarro-Gonzalez ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Forest Fires ◽  
Environmental Conditions ◽  
Climate Model ◽  
Wildland Fire ◽  
Current Phase ◽  
Electrical Characteristics ◽  
Geophysical Research ◽  
Lightning Discharges ◽  
Total Lightning

&lt;p&gt;About 5% of the wildfires in the Mediterranean basin are produced by lightning [1]. Lightning-ignited fires tend to occur in remote areas and can spread significantly before suppression. The occurrence of lightning-caused fires is closely related with intense drought periods and high temperatures [2]. Therefore, drier conditions and higher temperatures in a changing climate are expected to lead to a future increase in lightning-ignited fires occurrence. The development of a lightning-ignited fire parameterization for Earth system models arises as a necessary tool to predict the future occurrence of these extreme events and to study their impact on atmospheric chemistry.&lt;/p&gt;&lt;p&gt;Long Continuing Current lightning (LCC-lightning), preferable taking place in dry thunderstorms, is believed to be the main precursor of lightning-ignited fires. This was originally proposed by McEachron and Itagenguth in 1942 [3] working with laboratory sparks, which suggested that ignition by natural lightning is usually caused by a discharge having an unusual long-continuing current phase. Later in 1967 this hypothesis was confirmed by Fuquay &lt;em&gt;et al.&lt;/em&gt; [4].&lt;/p&gt;&lt;p&gt;In this work, we analyse three fire databases of lightning-ignited fires in Spain, Portugal and Southern France between 2009 and 2015. Furthermore lightning measurements from the World Wide Lightning Location Network (WWLLN) and the Earth Networks Total Lightning Network (ENTLN), and land and atmospheric variables from the new ERA-5 reanalysis are combined to investigate the electrical characteristics and environmental conditions of the fires. This preliminary data analysis will be useful to set new relationships between the characteristics of thunderstorms and the initiation of wildfires. It is the first step towards the development of a detailed lightning-ignited fire parameterization for the atmospheric chemistry-climate model EMAC.&lt;/p&gt;&lt;p&gt;[1] V&amp;#225;zquez, A., and Moreno, J. M. (1998). Patterns of lightning-, and people-caused fires in peninsular Spain. International Journal of Wildland Fire, 8(2), 103-115.&lt;/p&gt;&lt;p&gt;[2] Pineda, N., and Rigo, T. (2017). The rainfall factor in lightning-ignited wildfires in Catalonia. Agricultural and Forest Meteorology, 239, 249-263.&lt;/p&gt;&lt;p&gt;[3] McEachron, K. B., and Itagenguth, J. It (1942), Effect of lightning on thin metal surfaces, AIEE Trans., 61, 559-564, 1942.&lt;/p&gt;&lt;p&gt;[4] Fuquay, D. M., Baughman R. G, Taylor, A. R. and Hawe, R. G. (1967). Characteristics of seven lightning discharges that caused forest fires. Journal of Geophysical Research, 72 (24).&lt;/p&gt;

scholarly journals Efficient nested-PCR-based method development for detection and genotype identification of Acanthamoeba from a small volume of aquatic environmental sample

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tsui-Kang Hsu ◽  
Jung-Sheng Chen ◽  
Hsin-Chi Tsai ◽  
Chi-Wei Tao ◽  
Yu-Yin Yang ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Nested Pcr ◽  
In Silico ◽  
Environmental Samples ◽  
Method Development ◽  
Small Volume ◽  
Detection Efficiency ◽  
Genotyping Method ◽  
Pcr Method

AbstractAcanthamoeba spp. are opportunistic human pathogens that cause granulomatous amoebic encephalitis and keratitis, and their accurate detection and enumeration in environmental samples is a challenge. In addition, information regarding the genotyping of Acanthamoeba spp. using various PCR methods is equally critical. Therefore, considering the diverse niches of habitats, it is necessary to develop an even more efficient genotyping method for Acanthamoeba spp. detection. This study improved the sensitivity of detection to avoid underestimation of Acanthamoeba spp. occurrence in aquatic environmental samples, and to accurately define the pathogenic risk by developing an efficient PCR method. In this study, a new nested genotyping method was established and compared with various PCR-based methods using in silico, lab, and empirical tests. The in silico test showed that many PCR-based methods could not successfully align specific genotypes of Acanthamoeba, except for the newly designed nested PCR and real-time PCR method. Furthermore, 52 water samples from rivers, reservoirs, and a river basin in Taiwan were analysed by six different PCR methods and compared for genotyping and detection efficiency of Acanthamoeba. The newly developed nested-PCR-based method of genotyping was found to be significantly sensitive as it could effectively detect the occurrence of Acanthamoeba spp., which was underestimated by the JDP-PCR method. Additionally, the present results are consistent with previous studies indicating that the high prevalence of Acanthamoeba in the aquatic environment of Taiwan is attributed to the commonly found T4 genotype. Ultimately, we report the development of a small volume procedure, which is a combination of recent genotyping PCR and conventional real-time PCR for enumeration of aquatic Acanthamoeba and acquirement of biologically meaningful genotyping information. We anticipate that the newly developed detection method will contribute to the precise estimation, evaluation, and reduction of the contamination risk of pathogenic Acanthamoeba spp., which is regularly found in the water resources utilised for domestic purposes.

scholarly journals 3D Total Lightning Observation Network in Tokyo Metropolitan Area (Tokyo LMA)

2021 ◽  
Vol 16 (4) ◽  
pp. 778-785
Author(s):  
Namiko Sakurai ◽  
Koyuru Iwanami ◽  
Shingo Shimizu ◽  
Yasushi Uji ◽  
Shin-ichi Suzuki ◽  
...  
Keyword(s):  
Real Time ◽  
Metropolitan Area ◽  
Earth Science ◽  
Three Dimensional ◽  
Tokyo Metropolitan ◽  
Tokyo Metropolitan Area ◽  
Observation Network ◽  
Mapping Array ◽  
Total Lightning ◽  
Prediction Techniques

The National Research Institute for Earth Science and Disaster Resilience deployed a lightning mapping array (LMA) in the Tokyo metropolitan area in March 2017. Called the “Tokyo LMA,” it obtains detailed three-dimensional observations of the total lightning activity (cloud-to-ground and intracloud flashes) in storms. The network initially consisted of 8 receiving stations, expanded to 12 stations in March 2018. Real-time total lightning images were first opened on the webpage in Japan. Real-time observations from the Tokyo LMA will be used in nowcasting lightning hazards and mitigating lightning disasters. Archived data will be used to develop lightning prediction techniques and a lightning climatology for the Tokyo metropolitan area.

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