Estimation of Lightning-Generated NO_(x) in the Mainland of China Based on Cloud-to-Ground Lightning Location Data

Lightning-generated nitrogen oxides(LNO_(x))have a major influence on the atmosphere and global climate change.Therefore,it is of great importance to obtain a more accurate estimation of LNO_(x).The aim of this study is to provide a reference for the accurate estimation of the total LNO_(x) in the mainland of China based on cloud-to-ground lightning(CG)location data from 2014 to 2018.The energy of each CG flash was based on the number of return strokes per CG flash,the peak current of each return stroke,and the assumed CG breakdown voltage.The energy of intracloud lightning(IC)was based on the estimated frequencies of IC and the assumed energy of each IC flash.Combining the energy of lightning and the number of nitric oxide(NO)molecules produced by unit energy(ρno),the total LNO_(x) production in the mainland of China was determined.The LNO_(x) in the mainland of China estimated in this study is in the range(0.157-0.321)×10^(9) kg per year[Tg(N)yr-1],which is on the high end of other scholars’works.Negative cloud-to-ground lightning(NCG)flashes produce the most moles of NO_(x),while positive cloud-to-ground lightning(PCG)flashes produce the least total moles of NO_(x).The breakdown voltage of PCG is greater than that of IC or NCG,while the latter has a greater output of LNO_(x).

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

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 branches, two of which have an average propagation speed at the order of 10^5 m s-1, and the other of 10^6 m s-1, respectively. All the DNLs contained in the observed natural negative lightning flashes, except the attempted leader, propagate with gradually increasing luminosity and increasing speed in whole.

The Characteristics of Cloud-to-Ground Lightning Activity with Severe Thunderstorm Wind in South and North China

The characteristics of cloud-to-ground(CG) lightning activity with severe thunderstorm wind(STW) in South and North China are analyzed using CG lightning data, radar data, and serious weather reports. The percentage of positive CG(PCG) flashes with STW in North China is larger than that in South China. STW takes place during the period when the total CG and PCG density is increasing fastest. STW also occurs close to the high-value center of CG and PCG density. In North China, the CG and PCG density in the grid of STW maximizes approximately 20 minutes after the STW occurs; while in South China, the PCG density and percentage of PCG in the grid of STW maximizes about 10 minutes before the occurrence of STW. The high-value centers of CG density and PCG density in North China move slightly faster than those in South China, which is opposite to the rate of increasing CG activity.

Temporal and Spatial Distribution of Lightning Activity in Ulanqab City

From January 2020 to December 2021,Ulanqab Meteorological Bureau of Inner Mongolia used VLF/LF lightning locator to carry out three-dimensional lightning monitoring in Ulanqab City,and compared with ADTD lightning location data in the same period.The results show that both VLF/LF lightning locator and ADTD lightning locator had excellent monitoring ability for lightning during flood season in Ulanqab.VLF/LF lightning locator was slightly superior to ADTD lightning locator in observation accuracy,the observation ability of low-current cloud-to-ground lightning,intracloud lightning observation and so on.There were obvious temporal and spatial characteristics of cloud-to-ground lightning during flood season in Ulanqab,and there was a certain correlation between the areas where lightning appeared frequently and surface water.Intracloud lightning was mainly concentrated at a height of 1-7 km.Negative cloud-to-ground lightning accounted for about 75%of total cloud-to-ground lightning,and negative intracloud lightning accounted for 39%of total intracloud lightning.

Characteristics of thunderstorms and lightning flashes in the Chinese inland plateau

The electrical characteristics of thunderstorms in three different altitude regions of the Chinese inland plateau have been analyzed in this paper. The results show, according to the polarity of the surface electric （E） field, that the thunderstorms can be divided into two categories in the study regions： one showing the normal tripole electrical charge structure （normal-type）, and the other showing the special tripole charge structure with a larger-than-usual lower positive charge center （LPCC） at the base of thunderstorm （special-type）, where the induced surface E field is controlled by the LPCC when a thunderstorm is overhead. We find that the two types of thunderstorms have different occurrences in different regions, and the percentage of special-type thunderstorms increases with the altitude. On the whole, the flash rate of thunderstorms is quite low, and the mean value is about 1-3 fl/min, while the flash rate of special-type is slightly greater than that of the normal-type thunderstorm. The statistical results of cloud-to-ground flash （CG） numbers indicate that the ratio of ＋CG flash increases with the altitude, with the value about 14.7 percent through 25.4 percent.

Revision of CG Flash Density Based on Lightning Location Data

Using the data of the Lightning Location System( LLS) over Hubei Province,through the analysis of the distribution characteristics of CG( Cloud-to-Ground) flash density in 2015,it was found that the layout of the detection station had influence on the spatial distribution of lightning.Grid CG flash density data were used to characterize the spatial distribution of the CG flash,and station distance factor was used to characterize the detection station layout. The result showed that there existed negative correlation between density and factor,significant correlation between the density component and the factor for the lightning current amplitude of 5 to 30 kA,and insignificant correlation between >30 kA of density component and factor. So it is necessary to revise the density to eliminate the influence of the station layout. On the basis of the linear regression method and its residual theory,the revision model of the grid CG flash density and the statistical model of relative detection efficiency were established. The result consistency of segment and non-segmented revision of the density was verified. Through the contrastive analysis of theoretical detection efficiency and relative detection efficiency,the feasibility for revision method of CG flash density and the statistical method of relative detection efficiency was also verified.

Characteristics of Cloud-to-ground Lightning during a Squall Line Process outside of the Subtropical High

Based on the monitoring data of cloud-to-ground( CG) lightning positioning network and Doppler weather radar as well as MICAPS1°× 1° objective analysis field,a squall line process outside of the subtropical high in low-latitude plateau on May 7,2010 was analyzed. The results showed that wind direction shear between low and high levels and low-level convergence zones provided favorable circulation background for the strong thunderstorm process,while high energy and high humidity,strong thermal instability and ascending motion at low and middle levels offered beneficial environmental conditions for the formation of the thunderstorm. 9 620 return strokes of cloud-to-ground lightning were monitored by the lightning positioning network,and cloud-to-ground lightning was distributed like bands between 584 and 586 hP a. The occurrence of cloud-to-ground lightning was mainly related to echo top and echo intensity at-10 ℃ stratification height,and it mainly appeared in zones where echo top height was larger than 13 km and echo intensity at-10 ℃ stratification height was 35-40 dB Z. Wind convergence and maintaining of high radial velocity were favorable for the development of convective echoes and occurrence of cloud-to-ground lightning.

Study on the Scope of Small Amplitude of Cloud-to-ground Lightning in Lightning Weather Monitoring

Based on lightning location data in Chongqing region during 1999-2008,the frequency of lightning in various amplitude ranges and its annual variations were analyzed firstly.Afterwards,with the aid of matlab mathematical software,the distribution of the lightning location data was fitted using logarithmic normal distribution function.The results showed that after data of cloud-to-ground lightning with current amplitude from-5 to5 kA were deleted from lightning location data,the statistical characteristics of cloud-to-ground lightning could be reflected well.Meanwhile,lightning with current amplitude from-5 to 5 kA accounted for 1.05%（less than 2%）,which accorded with the detection principle of lightning position indicator（there existed error detection）.Therefore,cloud-to-ground lightning with current amplitude of-5-5 kA in lightning location data of Chongqing region was defined as small amplitude of cloud-to-ground lightning,which could provide scientific references for the processing of lightning location data in Chongqing region as well as analysis and quality control of lightning location data in other regions.

Studies on the Distribution Characteristics of the Cloud-to-Ground Lightning and Its Disasters Prevention in Xinjiang, China in 2017

Xinjiang, China is affected by geographical terrain and other factors, and is prone to lightning disasters. In order to effectively carry out lightning protection and disaster reduction work and improve defense capabilities, based on the data of lightning location monitoring in Xinjiang in 2017 and the statistics reports of the lightning disasters from 2015 to 2017, the characteristics of the cloud-to-ground (CG) lightning activities and disasters in Xinjiang were statistically analyzed. The results show that the CG lightning in Xinjiang is mainly the negative one, accounting for 79.7% of the total lightning. In 2017, the distribution of positive, negative and total the CG lightning months mainly focuses on June to August, and the main occurrence period is from 14 to 23 hours. The intensity of total the CG lightning and negative the CG lightning mainly distributes from 20 to 40 kA, and the peak value appears in 30 kA. The CG lightning intensity is mainly distributed in 30 - 70 kA. The distribution of the CG lightning density in Xinjiang is larger in the north than in the south and larger in the west than in the east. Lightning disasters mainly occur from May to August, accounting for 93.2 percent of the total, with the largest number in June. From 2005 to 2017, 44.6% of lightning accidents occurred in farming and pastoral areas, followed by civil electronic equipment damage. In addition, electrical equipment, buildings and factory equipment are damaged by lightning strikes to varying degrees.

Characteristics of Cloud-to-ground Lightning during a Local Rainstorm in Meizhou City

Based on cloud-to-ground lightning data of lightning location system,Doppler radar data,and precipitation data of regional automatic weather stations,the characteristics of cloud-to-ground lightning during a local rainstorm on June 4,2016 in Meizhou City were analyzed. The results showed that the spatial distribution of cloud-to-ground lightning from 14： 00 to 20： 00 on June 4,2016 in Meizhou City had obvious local characteristics,and the proportion of negative lightning was larger than that of positive lightning（ only 16. 8%）. The concentration period of positive lightning coincided with that of cloud-to-ground lightning. The peak of proportion of positive lightning lagged behind the peak of cloud-to-ground lightning,and appeared in the late period of thunderstorm disappearance. The dense area of cloud-to-ground lightning and the area with heavy rainfall coincided with the area with strong radar echoes. Doppler weather radar data had the feature of the headwind zone,strong combined reflectivity,vertical height of strong echoes,high echo top,and fast radial movement. The peak of cloud-to-ground lightning appeared one hour earlier than that of precipitation. There was no significant correlation between the frequency of cloud-to-ground lightning and precipitation. The peak of negative lightning corresponded to that of positive lightning,and cloud-to-ground lightning ended earlier than rainfall. After the peak of precipitation,convective system rapidly weakened and disappeared. Precipitation and the frequency of cloud-to-ground lightning fluctuated frequently during the whole process. The jumps and peaks of negative lightning were indicative of rainfall changes.

Analysis on Lightning Activities and Its Disastrous Climate Characteristics in Shandong Province

By using the reported data of lightning disaster and the data of lightning monitoring network in Shandong Province since its establishment,the lightning activities and the disaster climate characteristics in Shandong Province were analyzed.The data were processed by lattice formulation,and the spatial and temporal distribution characteristics of positive and negative CG flashes were given.The parameter characteristics of positive and negative ground lightning and its relationship with the lightning disasters were analyzed.And the lightning parameter characteristics of lightning in major cities of Shandong Province were analyzed.

High-Energy Atmospheric Physics: Ball Lightning

This article proposes an explanation for High-Energy Atmospheric phenomena through the frames of Hypersphere World-Universe Model (WUM). In WUM, Terrestrial Gamma-Ray Flashes (TGFs) are, in fact, Gamma-Ray Bursts (GRBs). The spectra of TGFs at very high energies are explained by Dark Matter particles annihilation in Geocorona. Lightning initiation problem is solved by GRBs that slam into thunderclouds and carve a conductive path through a thunderstorm. We introduce Multiworld consisting of Macro-World, Large-World, Small-World, and Micro-World, characterized by suggested Gravitational, Extremely-Weak, Super-Weak, and Weak interaction respectively. We propose a new model of Ball Lightning formation based on the Dark Matter Core surrounded by electron-positron plasma in the Small-World.

THE STATISTIC RELATION BETWEEN LIGHTNING AND CINRAD DOPPLER RADAR ECHOES IN CENTRAL GUANGDONG

Based on the CINRAD Doppler radar data in Guangzhou and the lightning data in 2004 by power suppliers of Guangdong, statistical study is done by overlaying lightning＇s position on radar＇s echo. The result shows the followings. The concentrated period in which more negative lightning occurred at the middle levels （2 - 14 km）, where radar echo was moderate （12 - 45 dBz）, rather than at the low levels with the weakest echoes or at high levels with the strongest echoes. At levels 3 - 11 km, where the radar echo was between 10 dBz and 35 dBz, the area of negative lightning was much larger in central Guangdong than in the rest of the province. At levels 0.5 - 7 krn where the radar echoes were between 44 dBz and 51 dBz, the probability for a point to have negative lightning varies from 0.4 to 0.7.

AHP Model-Based Risk Assessment of Lightning in Meizhou

Based on the cloud-to-ground（ CG） lightning flashes data and other related data from 1999 to 2016,the lightning risk zoning of Meizhou was conducted by using the analytic hierarchy process（ AHP） model. The model considered the natural conditions,social economic conditions and other factors,and the main assessment factors were selected,containing ＂ flash density,lightning current intensity,annual thunderstorm days,lightning disaster frequency,construction area per capita and GDP per capita＂,in order to establish the evaluation model,and divide the level of risk. The results showed that the lightning risk in Meizhou area roughly had the trend of ＂ center higher than all-around,the south higher than the north,the west higher than the east＂. High-risk area was in the most region of Meijiang District and central region of Meixian District,and Wuhua County was next high-risk area. Xingning City and Fengshun County were medium risk areas,most of the other were low risk area. The result of regionalization was consistent with the actual situation,and the evaluation method was scientific and effective. Through the analysis of the lightning risk zoning,this paper could provide a scientific basis for the lightning protection and disaster reduction in the region in the future.

Statistical Analysis on Lightning Characteristics in Hebei Province

By using monitoring data of lightning locating system in Hebei during 1999- 2010 and lightning disaster data in Hebei during 2002- 2010,temporal-spatial distribution characteristics of ground flash and lightning disaster in Hebei Province were analyzed. Annual,monthly and daily changes of ground flash,lightning current intensity and ground flash density in Hebei were analyzed,and we compared ground flash with lightning disaster distribution.

Discussion on Common Problems in Risk Assessment of Lightning Disaster

The problems in calculating parameters of equivalent collection area,earth resistivity and lightning protection category as well as their effects on lightning disaster risk assessment were analyzed,and practical examples proved the effects of those differences on lightning protection identification,intercept efficiency calculation in evaluating lightning disaster risk. In the meantime,several new concepts,such as the height of buildings for lightning protection were defined,and a fixed radius value was set to the ground flash density for calculation,establishing the ground flash density formula to solve the problems in parameter calculation,which would be beneficial to promote the standardization of lightning disaster risk assessment.

基于归闪的湖北省两套闪电定位系统对比分析

为研究湖北省两套闪电定位系统,在归闪的基础上研究分析了2015—2020年湖北地区地闪数据,对闪电频次、时空分布、电流强度月分布、雷电流幅值累积概率等主要参数进行了比对分析,研究结果表明:ADTD-2系统在定位正地闪强度存在局部异常值外,比ADTD-1系统具有更高的探测效率,其中正地闪的探测效率比负地闪提升幅度更高,探测负地闪回击的时间分辨率也比ADTD-1系统高,ADTD-2闪电数据整体优于ADTD-1数据。

基于TEROS的自然闪电X射线暴观测研究

本文报道了国内首个自然闪电高能辐射(Lightning Energetic Radiation,LER)多点观测结果.基于自主研发的雷暴高能辐射观测系统(Thunderstorm Energetic Radiation Observation System,TEROS),在2021年夏季观测期成功捕获3次自然LER事件,结合闪电定位、低频快电场变化、回击峰值电流等其他资料,对3次事件的高能辐射特征进行研究.分析发现:3次LER事件均于负地闪下行先导的最后阶段被探测到,是典型的X射线暴,且均具有MeV能量的单光子,最大能量超过2.2 MeV;伴随梯级先导出现的X射线暴持续时间为数百μs,伴随不规则直窜先导的X射线暴持续时间为数十μs,主要与先导发展速度有关;相应回击峰值电流最大的1次事件具有最高的单光子能量、最大的单位面积沉积总能量和最多的爆发过程数量,随着接近回击时刻,该事件还表现出与电场变化一致的增强趋势,表明先导头部电场是影响高能辐射产生的重要因素;随到达强度降低,高能辐射信号逐渐由束流模式向单光子模式转变,呈现出与地球伽马射线闪类似的现象学特征,更多乃至所有的爆发过程无法被探测到,高能辐射可能是闪电发展过程中的普遍现象.

双层均匀口袋电荷模型下闪电起放电特征的数值模拟研究

大量基于观测的研究认为闪电通道的延展尺度与电荷的分布形态息息相关,强对流区频繁始发的小尺度闪电对应雷暴云内的背景电荷很有可能为“口袋电荷”的分布模式。为验证口袋电荷背景下能形成此类云闪并给出该电荷背景下闪电起、放电的一般规律,本研究将闪电放电参数化方案植入到双层均匀口袋电荷模型中开展了大量随机模拟试验。模拟过程中固定了电荷区的总尺度,通过改变电荷对数进行探讨,着重讨论各电荷背景下闪电起始和放电行为的异同。模拟结果表明:(1)随着电荷对数的增加,闪电启动需要的电荷浓度和电荷总量均增加。(2)小电荷区的水平垂直尺度比是影响闪电起始行为的关键因子,除此之外各电荷背景下闪电起始位置和启动概率在水平、垂直方向上的差异还与多对电荷的空间配置关系和逃逸击穿阈值有关。(3)闪电的水平、垂直范围和面积均与小电荷区的尺度息息相关,小电荷区的几何特征限制了闪电的空间特征。(4)电荷区的分布也显著影响着闪电的发展形态,各电荷背景下闪电初始先导角度的分布范围和集中区域有所差异。相较于电荷区倾向于为扁平椭圆形的情况,当电荷区垂直与水平尺度相等时,初始先导角度变化范围明显增大,水平发展的个例明显增多。

不同矿藏地区雷电参数分布特征及对比分析

为研究雷电参数与矿藏之间的关系,根据雷电定位系统2013年1月至2022年12月的监测资料,对四川凉山州5个不同矿藏地区(镍矿、铁矿、铜矿、钨矿和锡矿)的地闪频次、雷电流幅值、雷电日等雷电参数分布特征进行了统计分析。结果表明,不同矿藏地区的地闪频次、雷电流幅值、雷电日差异较为明显,在年变化、月变化和日变化中:镍矿地区的地闪频次相较于其余4个矿藏地区最为突出,其余矿藏地区的地闪次数也有明显的差异;不同矿藏地区的雷电流幅值有明显差异,其中钨矿的雷电流平均幅值最大,镍矿的雷电流平均幅值最小;不同矿藏地区的雷电日也有明显的差异,镍矿地区10年的平均雷电日最大,铜矿和钨矿地区次之,铁矿和锡矿地区最小。