Weitao Lyu

Weitao Lyu
Chinese Academy of Meteorological Sciences · State Key Laboratory of Severe Weather

Ph.D.

About

159
Publications
23,752
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1,991
Citations
Additional affiliations
June 2011 - July 2015
Chinese Academy of Meteorological Sciences
Position
  • Managing Director

Publications

Publications (159)
Article
Full-text available
Plain Language Summary Unlike the classical rocket‐triggered lightning that a small rocket is launched upward trailing a grounded steel wire, the altitude‐triggered lightning is conducted by a rocket dragging an electrically floating wire, where the distance between the bottom of the wire and the ground is tens to hundreds of meters. The discharges...
Article
Overhead ground wire (OGW) is erected to protect transmission conductors from lightning strikes. However, OGW can be damaged or even ruptured due to lightning strikes, which threatens the stable operation of the power system. Thus, it is necessary to study the lightning-induced damage or rupture mechanism to provide a theoretical guidance for the s...
Article
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A triggered lightning flash (TLF) provides a unique perspective on the relationship between spatiotemporal proximity flashes, owing to its determined location and time, convenient direction measurement, and explicit association with the charge region. In this study, 3-D lightning location, current measurement, and atmospheric average electric field...
Article
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Using the spectral data of a lightning continuing discharge process observed on the 600‐m‐high Canton Tower, experimental verification of the optical thickness of lightning neutral nitrogen (NI) and neutral oxygen (OI) radiation in the near‐infrared spectrum is presented first by comparing the measured relative intensities of two NI multiplets with...
Article
Thunderstorm activity over the Qinghai–Tibet Plateau (QTP) has important climatic effects and disaster impacts. Using the thunderstorm feature dataset (TFD) established based on the black body temperature (TBB) and cloud classification (CLC) products of the Fengyun-2E (FY-2E) geostationary satellite, as well as the lightning data of the World Wide...
Article
The lightning current on the 600-m high Canton Tower was measured directly for the first time, using a Rogowski coil installed at a height of 492 m above ground level. Return-stroke current measurements for three single-stroke downward negative flashes and two multiple-stroke upward negative flashes were presented and preliminarily analysed by comb...
Article
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The discharge signal in the initial stage of lightning is weak. The revelation of the discharge mechanism at this stage depends especially on close observation. In this study, a continuous interferometer (CINTF) was used to observe the initial stage of the upward positive leader (UPL) of the triggered lightning in Conghua District, Guangzhou City,...
Article
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High‐speed video data were used to analyze the initiation and propagation of 36 needles and their associated 306 flickering events observed in a single‐stroke positive cloud‐to‐ground (+CG) flash. The needles occurred during the return‐stroke later stage and the continuing current, within approximate 10 ms after the onset of the +CG return stroke....
Article
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Based on the high‐speed video records of 54 lightning flashes striking on a cluster of tall buildings in Guangzhou and the return stroke peak currents provided by lightning location systems, this paper analyzed the two‐dimensional (2D) first‐return‐stroke striking distances (SD) of lightning flashes to buildings with a height ranging from 100 to 60...
Article
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Narrow bipolar events (NBEs) are signatures in radio signals from thunderstorms observed by ground-based receivers. NBEs may occur at the onset of lightning, but the discharge process is not well understood. Here, we present spectral measurements by the Atmosphere‐Space Interactions Monitor (ASIM) on the International Space Station that are associa...
Article
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By using the synchronous observation data obtained at the Tall‐Object Lightning Observatory in Guangzhou (TOLOG) of 2019, the electromagnetic characteristics of upward positive leader (UPL) ascending from the 600‐m high Canton Tower are examined, and are compared with the magnetic field (B‐field) radiation of UPL in rocket‐triggered lightning. Befo...
Article
The paper presents a systematic description about the observation scheme analysis and practical observation of artificially triggered lightning with a ground-based microwave radiometer together with other discharging observation instruments at Guangzhou Field Experiment Site for Lightning research and testing in Conghua, Guangdong in the thundersto...
Article
Weather forecasting requires comprehensive analysis from a variety of meteorological data. Recent decades have witnessed the advance of weather observation and simulation technologies, triggering an explosion of meteorological data which are collected from multiple sources (e.g. radar, automatic stations and numerical weather prediction) and usuall...
Article
Previous studies regarding the transient response of grounding systems have mainly focused on grounding grids with injected current, while there are few studies on adjacent unconnected grids. An "active-passive" grounding grid model was set up based on the artificially triggered lightning experiment, and the GPR data from 39 return strokes were mea...
Article
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An interesting downward positive cloud‐to‐ground lightning (DPCG) initiated by an upward negative cloud‐to‐ground lightning (UNCG) was recorded by the instruments installed at the Tall‐Object Lightning Observatory in Guangzhou. The characteristics of the discharges before and after the DPCG return stroke were investigated in detail using both optic...
Article
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High‐speed video and electric field change data were used to analyze the initiation and propagation of four predominantly vertical bidirectional leaders making connection to a predominantly horizontal channel previously formed aloft. The four bidirectional leaders sequentially developed along the same path and served to form a positive branch of th...
Preprint
Full-text available
Narrow bipolar events (NBEs) are signatures in radio signals from thunderstorms observed by ground-based receivers. They are electromagnetic waves radiated by impulsive currents of electrical discharges. They come with two polarities, the positive that brings negative charge aloft, and the negative, that brings negative charge towards the earth. Th...
Article
Lightning mapping with radio frequency location systems plays a more and more important role in understanding the mechanism of lightning discharges during thunderstorms. Here we present a comprehensive analysis of the electromagnetic field measurements and 3-dimensional (3D) mapping of two coincident lightning flashes: an upward positive flash (+CG...
Article
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Plain Language Summary The magnetic field sensor with high sensitivity has demonstrated its capability to resolve the weak discharging processes during the initial upward leader of rocket‐triggered lightning. However, the bandwidth of the magnetic sensor used in previous measurements was usually below 500 kHz, which restricts the identification of...
Article
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An approach for retrieving the leader channel charge density, leader current, ambient electric field, and space charge along a leader channel path from ground observations with a complicated ground condition was presented. With this approach, properties of two downward positive leaders (DPL1 and DPL2) struck at high‐rise buildings were studied base...
Article
In this two-part paper, influences from environmental factors on lightning in a convective storm are assessed with a model. In Part I, an electrical component is described and applied in the Aerosol-Cloud model (AC). AC treats many types of secondary (e.g. breakup in ice-ice collisions, raindrop-freezing fragmentation, rime-splintering) and primary...
Article
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The Fengyun-4A (FY-4A) Lightning Mapping Imager (LMI) is the first satellite-borne lightning imager developed in China, which can detect lightning over China and its neighboring regions based on a geostationary satellite platform. In this study, the spatial distribution and temporal variation characteristics of lightning activity over China and its...
Article
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The lightning research group of the Chinese Academy of Meteorological Sciences has carried out observations and experiments with artificially triggered lightning for more than ten years, and it accumulated thousands of examples of channel base current data on the return stroke of artificially triggered lightning prior to 2020. Based on the current...
Article
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The initiation of a leader is an important lightning discharge process, but how an upward positive leader (UPL) initiates is still not fully understood. The evolution characteristics of a UPL during its initial stage was systematically studied based on directly measured current data of 14 triggered lightning events in 2019. It was found that the in...
Article
Full-text available
The initiation of a leader is an important lightning discharge process, but how an upward positive leader (UPL) initiates is still not fully understood. The evolution characteristics of a UPL during its initial stage was systematically studied based on directly measured current data of 14 triggered lightning events in 2019. It was found that the in...
Article
The integrals of lightning current and its square over time, named as the electrical charge quantity and lightning current action integral, respectively, are indicative of the total charges and heat energy released by the lightning. The temperature of air molecules along the discharging path is thus increased and can be observed by a properly-confi...
Article
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The location accuracy of the U.S. National Lightning Detection Network (NLDN) has been evaluated using as ground‐truth rocket‐triggered lightning data or video records but only at a few specific locations. In this study, by using the NLDN data for the events attributable to lightning strikes to towers, the location error of the NLDN across the enti...
Article
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The application of empirical mode decomposition (EMD) in the analysis and processing of lightning electric field waveforms acquired by the Low-frequency E-field Detection Array (LFEDA) in China has significantly improved the capabilities of the low-frequency/very-low-frequency (LF/VLF) time-of-arrival technique for studying lightning discharge proc...
Article
An improved stochastic method for computer simulation of lightning leaders is developed based on the results from optical observation data. The development and attachment process of downward negative cloud-to-ground lightning in the near-ground area is simulated. The distribution of lightning strike points influenced by tall structures is statistic...
Article
This study quantifies the impacts of tropical cyclones (TCs) to the geographical and seasonal lightning activity over the northwest Pacific (5°–35°N, 100°–160°E), and examines the connection between the occurrence of TC lightning and El Niño–Southern Oscillation (ENSO). Lightning data from the World Wide Lightning Location Network (WWLLN) and best-...
Article
Using lightning observations from the Fengyun-4A Lightning Mapping Imager (FY-4A LMI), best-track data from Shanghai Typhoon Institute, bright temperature (TBB) data from Himawari-8 satellite, and composite reflectivity (CR) data from the South China radar network, this study investigates the spatiotemporal distribution of lightning activity and co...
Article
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It has been determined that the discharge of lightning current to ground through grounding grid results in high potential at the grounding grid and other nearby grounding grids, which is very destructive. In the present paper, based on artificially triggered lightning technology, the characteristics of the ground potential rise (GPR), the transient...
Article
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During the SHandong Triggering Lightning Experiment (SHATLE) in summer of 2014 and 2015 and the Guangdong Comprehensive Observation Experiment on Lightning Discharge (GCOELD) campaign in 2018, we have conducted the observations of the magnetic pulse bursts (MPBs) during the initial continuous current in negative rocket‐triggered lightning. The MPBs...
Article
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Plain Language Summary The lightning attachment process is still one of the most poorly documented lightning processes. This process consists of two phases: the development of one or more upward leaders extending from grounded objects toward the approaching downward leader and the so‐called breakthrough phase (final jump; e.g., Rakov & Tran, 2019,...
Article
Using high-speed video cameras operating with framing rates of 20 and 525 kfps, we imaged the attachment process of a natural negative cloud-to-ground flash, occurring at a distance of 490 m. Nine upward leaders were observed. A total of 12 space stems/leaders in 47 steps of the downward negative stepped leader were captured. The two-dimensional le...
Article
The spectra with wavelength range of 390 nm to 660 nm of triggered lightning were observed in Guangdong Area using a slitless spectrograph. The characteristics of the lightning spectra during the initial continuous current and return strokes were analyzed, and the differences between the metal section and air section of the lightning channel were c...
Article
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Accurate lightning forecast is significant for disaster prevention and reduction. However, the mainstream lightning forecast methods, which mainly rely on numerical simulations and parameterizations, can hardly cope with the spatiotemporal deviations. Meanwhile, the rapid and complex evolution of lightning regions go beyond the traditional extrapol...
Article
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Plain Language Summary In this paper, we present high‐speed video observations of recoil leaders (RLs) which were not obscured by the cloud. We examined the initial positions, morphology, and dynamics of RLs in a Canton‐Tower upward flash. Out of a total of 21 RLs, 7 evolved into dart (or dart‐stepped) leaders, attaching to the Tower and producing...
Article
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The properties of initial leaders (ILs) of 1,056 flashes in two thunderstorms in Guangzhou, China, are analyzed. The median values of IL properties are 11.1 ms for duration, 2.2 km for vertical distance, 2.7 km for 3‐D distance, 1.9 × 10⁵ m/s for vertical displacement speed, 2.4 × 10⁵ m/s for 3‐D displacement speed, 28° for angle between the IL's d...
Conference Paper
Full-text available
Lightning as a natural phenomenon poses serious threats to human life, aviation and electrical infrastructures. Lightning prediction plays a vital role in lightning disaster reduction. Existing prediction methods, usually based on numerical weather models, rely on lightning parameterization schemes for forecasting. These methods, however, have two...
Article
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Plain Language Summary During the last 20 years, besides the location of return stroke, finer and more accurate positioning of total lightning based on lightning low‐frequency discharge signals can be achieved by using the time of arrival method. The Chinese Academy of Meteorological Sciences developed a lightning Low‐frequency E‐field Detection Ar...
Article
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Based on fast electric field waveforms of the Low-frequency E-field Detection Array (LFEDA), we introduce the time reversal technique into lightning three-dimensional location for the first time and propose a new algorithm for the three-dimensional location of lightning low-frequency discharges. Without using complex filtering algorithms to remove...
Article
This paper analyzes the potential transferred between two independent grounding grids located 40 m apart, one of which, called the active grid, was injected with current of rocket-triggered lightning flashes. The transferred potentials in another grid, called the passive grid, and the transient response of the surge protective device (SPD) in the p...
Article
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Tall objects are easy to trigger upward flashes. They also provide more opportunities for observation of upward flashes and a suitable platform for analyzing the intiation and development of upward flashes. Upward flashes are usually divided into two types, one is self-initiated and the other is triggered by environment, and the latter type is ofte...
Article
Based on dual-station optical records, electric field and radar data, a detailed analysis of an instance of upward lightning initiated from Canton Tower, in the city of Guangzhou, Guangdong Province, China, is presented. The upward lightning was triggered by a positive cloud-to-ground (PCG) flash nearby. The upward lightning channel and part of the...
Article
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A positive cloud-to-ground (+CG) lightning flash containing a single stroke with a peak current of approximately +310 kA followed by a long continuing current triggered seven upward lightning flashes from tall structures. The flashes were observed on 4 June 2016 at the Tall Object Lightning Observatory in Guangzhou, Guangdong Province, China. The o...
Conference Paper
Full-text available
The integral of lightning current squared over time, named as the “lightning action integral”, is an indicator of Joule heat generated by lightning discharge. The temperature of air molecules is thus increased, which can be observed by a ground-based microwave radiometer for atmospheric temperature remote sensing. Observational experiments were per...
Article
We evaluate lightning electromagnetic fields along an ocean–land mixed propagation path generated by return strokes to wind turbines (WTs) using a three-dimensional finite-difference time domain method. In these simulations, we consider the following three cases: strikes to onshore WTs, strikes to offshore floating WTs, and strikes to onshore WTs i...