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High Voltage 2024年第1期9卷 163-171页

作者： Li Cai Yifeng Ke Wenchao Fan Ruisheng Yan Mi Zhou Jianguo Wang Yadong Fan Engineering Research Center of Ministry of Education for lightning Protection and Grounding Technology School of Electrical Engineering and AutomationWuhan UniversityWuhanChina

As the wind turbine height increases,the probability of multiple upward leaders flashes within the wind farm *** this study,an upward lightning flash containing 21 upward positive leaders(UPLs)initiated from different wind turbines in Zhangbei Wind Farm was *** average speed of the UPLs was 1.2×10^(5) m/s,which mostly decreased to zero before reaching the cloud *** four UPLs developed to cloud height,with prolonged periods of bright light on three of them and with a minimum duration of 126 ms.A total of nine return strokes occurred on the other two dissipated leader channels,and the numbers of strokes on the two channels was six and three,*** average interstroke interval for the return strokes was 10.5 *** of these nine return strokes had peak currents smaller than 10 *** high-speed video frames confirmed that competition does exist between the UPLs,and the range of shielding effects increases as the height of the ULs *** effect of fan rotation on the initiation of upward leaders and the shielding effect between the wind turbines and upward leaders are discussed.

关键词： flash return initiated

Assessing target optical camouflage effects using brain functional networks:A feasibility study

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Defence Technology（防务技术） 2024年第4期34卷 69-77页

作者： Zhou Yu Li Xue Weidong Xu Jun Liu Qi Jia Jianghua Hu Jidong Wu National Key laboratory of lightning Protection and Electromagnetic Camouflage Army Engineering University Nanjing 210007JiangsuChina Unit 31608 of PLA Xiamen 361000FujianChina School of Biological Sciences&Medical Engineering Southeast UniversityNanjing 210096JiangsuChina

Brain functional networks model the brain's ability to exchange information across different regions,aiding in the understanding of the cognitive process of human visual attention during target searching,thereby contributing to the advancement of camouflage *** this study,images with various camouflage effects were presented to observers to generate electroencephalography(EEG)signals,which were then used to construct a brain functional *** topological parameters of the network were subsequently extracted and input into a machine learning model for *** results indicate that most of the classifiers achieved accuracy rates exceeding 70%.Specifically,the Logistic algorithm achieved an accuracy of 81.67%.Therefore,it is possible to predict target camouflage effectiveness with high accuracy without the need to calculate discovery *** proposed method fully considers the aspects of human visual and cognitive processes,overcomes the subjectivity of human interpretation,and achieves stable and reliable accuracy.

关键词： Camouflage effect evaluation Electroencephalography(EEG) Brain functional networks Machine learning

Optical Observations on Propagation Characteristics of Leaders in Cloud-to-Ground lightning Flashes

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Acta meteorologica Sinica 2008年第1期22卷 66-77页

作者：吕伟涛张义军李俊郑栋董万胜陈绍东王飞 laboratory of lightning Physics and Protection Engineering Chinese Academy of Meteorological Sciences

Using 2 high-speed cameras, we have recorded 14 negative cloud-to-ground （CG） lightning flashes, half of which are natural and the others are artificially triggered. The two-dimensional （2D） propagation speed of different type leaders and the luminosity of lightning channel are analyzed in detail. Bidirectional leader processes are observed during the initial processes of two altitude triggered negative lightning （ATNL） flashes. The analysis shows： the propagation speed of the upward positive leader （UPL） before the initiation of the downward negative leader （DNL） is at the order of 10^4-10^5 m s-1; the UPL can be intensified by the initiation and development of the DNL in the way that the luminosity is enhanced and the speed is sped up; after initiation, the DNL in one ATNL flash propagates downward three times intermittently with interval of about 1 ms, while that in the other ATNL flash propagates downward continuously with a speed at the order of 10^5 m s^-1. In the five classical triggered negative lightning （CTNL） flashes, the propagation speeds of the UPLs vary between 0.35×10^5 and 7.71×10^5 m s-1, and the variations of their luminosities and speeds are quite complex during the development processes. Among the four observed natural negative lightning flashes occurred on the land, three have only one return stoke （RS） each and all of their DNLs have many branches with an average speed at the order of 10^5 m s-l; while the another one has 13 RSs. In the CG flash with 13 RSs, the DNL before the first RS has no obvious branch below 1.4 km above the ground, and its speed ranges from 2.2×10^5 to 2.3×10^6 m s-1 between the heights of 0.7 and 1.4 km and exceeds 3.9×10^6 m s-1 below 0.7 km; preceding the 4th RS, an attempted leader is observed with a speed ranging from 1.1× 10^5 to 1.1×10^6 m s-1 between 0.8 and 1.5 km. As for the three observed natural negative lightning flashes occurred on the sea, each has only one RS, and each DNL preceding the RS has a few branc

关键词： cloud-to-ground lightning propagation speed of leader luminosity of lightning channel highspeed photography

Simulation Study About the Influence of Atmospheric Stratification on lightning Activities

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Acta meteorologica Sinica 2008年第1期22卷 78-90页

作者：郑栋张义军吕伟涛马明孟青 laboratory of lightning Physics and Protection Engineering Chinese Academy of Meteorological Sciences

A 2D model about charging and discharging processes in thundercloud is used to simulate three differential atmospheric stratifications resulting in discrepant thunderstorm processes in Beijing region. The dynamic and microphysical processes in thunderstorm and their influence on lightning activities are also discussed. The results indicate that ascending velocity and water vapor are the most important factors to influence lightning activities. At the same time, they affect each other and are together controlled by atmospheric stratification. The magnitude of the ascending velocity determines the intensity of storm and the time when the thunderstorm matured. The thunderstorm with strong updrafts can reach a large height in a short time. Strong persistent updrafts and sufficient water vapor which help to generate more ice phase hydrometeors that directly influence charging and discharging process will prolong the mature stage of the thunderstorm and thereby enhance lightning activities. Though the big density of ice phase hydrometeors can be formed, it is difficult to sustain a long time in the condition of strong updrafts and scant water vapor. Under the condition of weak updrafts and sufficient water vapor in the whole levels, it is easy to form warm cloud process in which the ice phase process and lightning activities are weak. The favorable stratification conditions for strong lightning activities are the sufficient vapor in the lower atmosphere, moderate humidity in the mid troposphere. big instability energy and some suitable convective inhibition. Through calculating some atmospheric instability parameters, it is indicated that convective instability index smaller than -10℃ （negative means instable）, convective available potential energy larger than 1000 J kg-1, convective inhibition larger than 40 J kg-1 the 700-hPa potential equivalent temperature larger than 340 K and the 35%-85% humidity in the mid troposphere （700-400 hPa） are the advantageous conditions f

关键词： atmospheric instability parameters model hydrometeor electric structure

Impact of Updraft on Neutralized Charge Rate by lightning in thunderstorms:A Simulation Case Study

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Journal of Meteorological Research 2015年第6期29卷 997-1010页

作者：王飞张义军郑栋 State Key laboratory of Severe Weather Chinese Academy of Meteorological Sciences(CAMS) laboratory of lightning Physics and Protection Engineering CAMS

The rate of neutralized charge by lightning（RNCL） is an important parameter indicating the intensity of lightning *** total charging rate（CR）,the CR of one kind of polarity（e.g.,negative） charge（CROP）,and the outflow rate of charge on precipitation（ORCP） are proposed as key factors impacting RNCL,based on the principle of conservation of one kind of polarity charge in a *** this paper,the impacts of updraft on CR and CROP are analyzed by using a 3D cloud resolution model for a strong storm that occurred in Beijing on 6 September *** results show that updraft both promotes and inhibits RNCL at the same time.（1） Updraft always has a positive influence on *** correlation coefficient between the updraft volume and CR can reach *** of the updraft facilitates strengthening of RNCL through this positive influence.（2） Strengthening of the updraft also promotes reinforcement of *** correlation coefficient between the updraft volume and CROP is high（about0.9）,but this promotion restrains the strengthening of RNCL because the strengthening of CROP will,most of the time,inhibit the increasing of RNCL.（3） Additionally,increasing of ORCP depresses the strengthening of *** terms of magnitude,the peak of ORCP is equal to the peak of *** precipitation mainly appears after the lightning activity finishes,the depression effect of ORCP on RNCL can be ignored during the active lightning period.

关键词： lightning activity updraft neutralized charge charging rate charge amount

Post electrical or lightning injury syndrome: a proposal for an American Psychiatric Association's Diagnostic and Statistical Manual formulation with implications for treatment

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Neural Regeneration Research 2017年第9期12卷 1405-1412页

作者： Christopher J.Andrews Andrew D.Reisner Mary Ann Cooper Medicine The University of Queensland lightning and Electrical Injuries Mt Ommaney Family Practice Forensic Diagnostic Center of District Nine lightning Injury Research Program University of Illinois at Chicago African Centres for lightning and Electromagnetics Network

In the past, victims of electrical and lightning injuries have been assessed in a manner lacking a system- atic formulation, and against ad hoc criteria, particularly in the area of neuropsychological disability. In this manner patients have, for example, only been partially treated, been poorly or incorrectly diagnosed, and have been denied the full benefit of compensation for their injuries. This paper contains a proposal for diagnostic criteria particularly for the neuropsychological aspects of the post injury syndrome. It pays attention to widely published consistent descriptions of the syndrome, and a new cluster analysis of post electrical injury patients. It formulates a proposal which could be incorporated into future editions of the American Psychiatric Association＇s Diagnostic and Statistical Manual （DSM）. The major neuropsycholog- ical consequences include neurocognitive dysfunction, and memory subgroup dysfunction, with ongoing consequences, and sometimes including progressive or delayed psychiatric, cognitive, and/or neurological symptoms. The proposed diagnostic criteria insist on a demonstrated context for the injury, both specifying the shock circumstance, and also physical consequences. It allows for a certain delay in onset of symptoms. It recognizes exclusory conditions. The outcome is a proposal for a DSM classification for the post electrical or lightning injury syndrome. This proposal is considered important for grounding patient treatment, and for further treatment trials. Options for treatment in electrical or lightning injury are summarised, and future trials are foreshadowed.

关键词： electrical injury lightning injury neuropsychology neuropsychiatry injury American Psychiatric Association's Diagnostic and Statistical Manual

Total lightning Characteristics and Electric Structure Evolution in a Hailstorm

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Acta meteorologica Sinica 2009年第2期23卷 233-249页

作者：郑栋张义军孟青吕伟涛易笑园 laboratory of lightning Physics and Protection Engineering Chinese Academy of Meteorological Sciences Tianjin Meteorological Bureau

In this paper, total lightning data observed by SAFIR3000 3-D lightning Locating System was combined with radar data to analyze characteristics of the lightning activity and electric structure of a hailstorm that occurred in Beijing on 31 May 2005. The results indicated that there were two active periods for the lightning activity during the hailstorm process. The hail shooting was found in the first period. After the end of the hail shooting, lightning frequency decreased suddenly. However, more active lightning activities occurred in the second period with lots of them appearing in the cloud anvil region. The peak of the lightning frequency came about 5 min prior to the hail shooting. Only 6.16% of the total lightning was cloud-to-ground （CG） lightning, among which 20% had positive polarity. This percentage was higher than that in normal thunderstorms. In addition, heavier positive CG lightning discharge occurred before rather than after the hail shooting. In the stage of the hail shooting, the electric structure of the hailstorm was inverted, with the main negative charge region located around the -40℃ level and the main positive charge region around the -15℃ level. In addition, a weak negative charge region existed below the positive charge region transitorily. After the hail shooting, the electric structure underwent fast and persistent adjustments and became a normal tripole, with positive charge in the upper and lower levels and negative charge in the middle levels. However, the electric structure was tilted under the influence of the westerly wind in the middle and upper levels. The lightning activity and electric structure were closely related to the dynamic and microphysical processes of the hailstorm. It was believed that severe storms with stronger updrafts were more conducive to an inverted tripolar electric structure than normal thunderstorms, and the inverted distribution could then facilitate more positive CG lightning in the severe storms.

关键词： lightning activity electric structure non-inductive charging mechanism bidirectional leader

Climatology of lightning Activity in South China and Its Relationships to Precipitation and Convective Available Potential Energy

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Advances in Atmospheric Sciences 2016年第3期33卷 365-376页

作者： Dong ZHENG Yijun ZHANG Qing MENG Luwen CHEN Jianru DAN State Key laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081 laboratory of lightning Physics and Protection Engineering Chinese Academy of Meteorological SciencesBeijing 100081 lightning Protection Center of Guangdong Province Guangzhou 510080 Conghua Meteorological Bureau Guangzhou 510925

This study examined lightning activity and its relationship to precipitation and convective available potential energy （CAPE） in South China during 2001-12, based on data from the Guangdong lightning Location System, the Tropical Rainfall Measuring Mission satellite, and the ERA-Interim dataset. Two areas of high lightning density are identified： one over the Pearl River Delta, and the other to the north of Leizhou Peninsula. Large peak-current cloud-to-ground （LPCCG） lightning （〉75 kA） shows weaker land-offshore contrasts than total CG lightning, in which negative cloud-to-ground （NCG） lightning occurs more prominently than positive cloud-to-ground （PCG） lightning on land, While the frequency of total CG lightning shows a main peak in June and a second peak in August, the LPCCG lightning over land shows only a single peak in June. The ratio of positive LPCCG to total lightning is significantly greater during February-April than during other times of the year. Diurnally, CG lightning over land shows only one peak in the afternoon, whereas CG lightning offshore shows morning and afternoon peaks. The rain yield per flash is on the order of 107-108 kg per flash across the analysis region, and its spatial distribution is opposite to that of lightning density. Our data show that lightning activity over land is more sensitive than that over offshore waters to CAPE. The relationships between lightning activity and both precipitation and CAPE are associated with convection activity in the analysis region.

关键词： climate characteristics lightning precipitation CAPE large peak current land-offshore contrast

Semi-Idealized Modeling of lightning Initiation Related to Vertical Air Motion and Cloud Microphysics

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Journal of Meteorological Research 2017年第5期31卷 976-986页

作者： fei wang yijun zhang dong zheng liangtao xu wenjuan zhang qing meng state key laboratory of severe weather chinese academy of meteorological sciencesBeijing 100081 laboratory of lightning physics and protection engineering chinese academy of meteorological sciencesBeijing 100081

A three-dimensional charge^lischarge numerical model is used, in a semi-idealized mode, to simulate a thunder- storm cell. Characteristics of the granpel microphysics and vertical air motion associated with the lightning initiation are revealed, which could be useful in retrieving charge strength during lightning when no charge^diseharge model is available, The results show that the vertical air motion at the lightning initiation sites （Wini） has a cubic polynomial correlation with the maximum updraft of the storm cell （WceH_m^x）, with the adjusted regression coefficient R2 of ap- proximately 0.97. Meanwhile, the graupel mixing ratio at the lightning initiation sites （qg-ini） has a linear correlation with the maximum graupel mixing ratio of the storm cell （qg-cell-max） and the initiation height （Zini）, with the coeffi- cients being 0.86 and 0.85, respectively. These linear correlations are more significant during the middle and late stages of lightning activity. A zero-charge zone, namely, the area with very low net charge density between the main positive and negative charge layers, appears above the area of qg-oewm and below the upper edge of the granpel re- gion, and is found to be an important area for lightning initiation. Inside the zero-charge zone, large electric intensity forms, and the ratio of qice （ice crystal mixing ratio） to qg （graupel mixing ratio） illustrates an exponential relation- ship to qg-ini. These relationships provide valuable clues to more accurately locating the high-risk area of lightning initiation in thunderstorms when only dual-polarization radar data or outputs from numerical models without char- ging/discharging schemes are available. The results can also help understand the environmental conditions at light- ning initiation sites.

关键词： lightning initiation graupel ice crystal vertical air motion cloud microphysics

Analysis of Channel Luminosity Characteristics in Rocket-Triggered lightning

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Acta meteorologica Sinica 2008年第3期22卷 362-374页

作者：吕伟涛张义军周秀骥孟青郑栋马明王飞陈绍东郄秀书 laboratory of lightning Physics and Protection Engineering Chinese Academy of Meteorological Sciences State Key laboratory of Severe Weather(LaSW) Chinese Academy of Meteorological Sciences lightning Protection Center of Guangdong Province Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences

A comparison is made of the high-speed （2000 fps） lightning between two techniques. The analysis shows （UPL） in altitude-triggered negative lightning （ATNL） photographic records in rocket-triggered negative that： the initial speed of upward positive leader is about one order of magnitude less than that in classically triggered negative lightning （CTNL）, while the triggering height of ATNL is higher than that of CTNL; the afterglow time of metal-vaporized part of the lightning channel can endure for about 160-170 ms, thus the luminosity of the air-ionized part can reflect the characteristics of the current in the lightning channel better than that of the metal-vaporized part. According to the different characteristics of the luminosity change of the lightning channel, together with the observation of the electric field changes, three kinds of processes after return-stroke （RS） can be distinguished： the continuous decaying type without M component, the isolated type and the continuing type with M component, corresponding to different wave shapes of the continuous current. The geometric mean of the interval of RS with M component is 77 ms, longer than that （37 ms） of RS without M component. And the initial continuous current （ICC） with M component also has a longer duration compared to the ICC without M component. The distinction in the relative luminosity between the lightning channel before RS and that before M component is obvious： the former is very weak or even cannot be observed, while the latter is still considerably luminous.

关键词： rocket-triggered lightning high-speed photography lightning channel luminosity characteristics