Asia-Pacific Lightning Location Network (APLLN) and Preliminary Performance Assessment
"> Figure 1
<p>The location of 16 very low-frequency (VLF) band detection sites (shown as red squares) as of mid-December 2019. Each red box represents a site.</p> "> Figure 2
<p>(<b>a</b>) Block diagram of the VLF lightning sensor. (<b>b</b>) Photo of a VLF lightning detection site in Hangzhou, China.</p> "> Figure 3
<p>Signal filtering. The upper graph is the original signal, and the lower graph is the comparison of the filtering results of the Butterworth filter and the zero-phase filter on the original signal. The dotted line indicates the moment when the signal was triggered for sampling.</p> "> Figure 4
<p>Time and spectrum plots of electric field signals in the near (75 km) and far (2491 km) regions. The blue lines represent near-field lightning signals, (<b>a</b>) time-domain plot, and (<b>b</b>) spectrum plot. The red lines represent far-field lightning signals, (<b>c</b>) time-domain plots, and (<b>d</b>) spectrum plots. The marked time is the time <math display="inline"><semantics> <mrow> <msub> <mi>t</mi> <mn>0</mn> </msub> </mrow> </semantics></math> when the signal triggers sampling, and <span class="html-italic">d</span> is the distance from the lightning signal to the detection site.</p> "> Figure 5
<p>(<b>a</b>) Lightning signal in the VLF band and Hilbert envelope. (<b>b</b>) The enlarged view near the peak point of (<b>a</b>). The dotted line indicates the trigger moment.</p> "> Figure 6
<p>Schematic representation of VLF lightning propagation in the Earth-ionosphere. The pentagram represents a lightning detection site.</p> "> Figure 7
<p>Schematic diagram of the location method using spherical triangle. Lightning <span class="html-italic">L</span> traveled along the solid green line to sites P1 and P2. <span class="html-italic">O</span> is the center of the ball. <span class="html-italic">N</span> is the North Pole and <span class="html-italic">S</span> is the South Pole.</p> "> Figure 8
<p>(<b>a</b>) Spatial distribution of the mean location error that calculated by the Monte Carlo simulation. (<b>b</b>) Spatial distribution of the standard deviation of the location error that calculated by the Monte Carlo simulation. Each red box represents a site.</p> "> Figure 9
<p>The location error and standard deviation of the linear site distribution. (<b>a</b>) Location error distribution. (<b>b</b>) Standard deviation distribution. The 4 sites are distributed almost in a straight line. Each red box represents a site.</p> "> Figure 10
<p>Monte Carlo error simulation result of Asia-Pacific Lightning Location Network (APLLN) by using the unimproved Levenberg–Marquardt (L–M) positioning algorithm. (<b>a</b>) Location error distribution. (<b>b</b>) Standard deviation distribution. Each red box represents a site.</p> "> Figure 11
<p>A thunderstorm took place between 1:00 and 9:00 am on 26 May 2019, Beijing time. Different colors represent different time periods and each scattered dot represents a lightning. The range of thunderstorms is in the coastal areas of southwestern Guangxi, China.</p> "> Figure 12
<p>(<b>a</b>) Number of strokes detected by APLLN for different hours. (<b>b</b>) Stroke density distribution during the thunderstorm (during 1:00 to 9:00 am).</p> "> Figure 13
<p>(<b>a</b>) The distribution of lightning detection results of Advanced Direction-Time Lightning Detection System (ADTD) in different hours. Orange indicates all types of lightning, green indicates cloud-to-ground (CG) stroke, and purple indicates intracloud (IC) stroke. (<b>b</b>) IC and CG strokes as a percentage of total stroke in different hours.</p> "> Figure 14
<p>Distribution of lightning quantity and detection efficiency at different periods. The green bars represent the detection results of ADTD in different time periods, the red bars represent the number of shared events between ADTD and APLLN in different time periods, and the points and lines represent the detection efficiency of APLLN relative to ADTD.</p> "> Figure 15
<p>(<b>a</b>) Location offsets between the shared strokes, taking each ADTD stroke as the origin and plotting the corresponding APLLN stroke relative to it (ADTD−APLLN). The mean north–south offset is 5.43 km, displayed as the dotted red line, and the mean east-west offset is 4.35 km, displayed as the dashed red line. (<b>b</b>) Distribution of relative location accuracy. The solid blue line indicates the cumulative percentage of shared events.</p> "> Figure 16
<p>A thunderstorm occurred in southeast China. The figure shows the lightning location results of APLLN and World Wide Lightning Location Network (WWLLN), respectively. Each scatters represents a detected lightning stroke, with different colors indicating when the lightning occurred.</p> ">
Abstract
:1. Introduction
Novelty and Contributions
- In order to let more detection sites receive the same lightning signal, the average distance between APLLN sites is about 1000 km.
- This paper presented a method for VLF lightning signal processing, and designed a hardware circuit for VLF detection point lightning. The lightning signal envelope was calculated based on the Hilbert transform, and the peak value of the envelope was used as the arrival time of the lightning signal.
- The location algorithm was improved in this paper. The improved location algorithm obtains the initial location solution by the spherical triangular location method, and then optimizes the initial solution using the improved Levenberg–Marquardt (L–M) [13,14] non-linear least squares method. The detailed calculation steps are in Section 3.3.
- Compared with the traditional method that used the constant speed of light as the propagation factor, this paper introduces the propagation speed as a variable into the iterative algorithm and obtains better location results.
- The location accuracy of APLLN was simulated, and the detection performance of APLLN was evaluated based on the lightning location data of China’s three-dimensional lightning location network (generally known as ADTD).
2. Network and Instrumentation
3. Methodology
3.1. Signal Processing
3.1.1. Filtering
3.1.2. Classification
3.2. Time of Arrival
3.3. Lightning Location Algorithm
Algorithm 1 Improved Levenberg-Marquardt iterative algorithm |
Input: Time of arrival, ; The site No. (latitude and longitude), ; Convergence accuracy of the algorithm, ; Number of iterations, N;
Output: The distance and azimuth of the lightning from the main site, ; 1: Calculate the initial solution by using the spherical triangle location method, , and ; 2: Calculate the iterative solution by using the L-M algorithm, and the speed of propagation uses the speed of light, , and ; 3: Calculate the initial propagation speed of the lightning to each site, ; 4: Calculate the iterative solution by using the L-M algorithm, and the speed of propagation uses the , get , and ; Return: |
4. Simulation of Location Errors
4.1. Method of Evaluation
- (1)
- We assumed that lightning occurred in the center of each grid, and the height of the lightning is uniformly set to 0 km. At the same time, assuming that the electromagnetic signal emitted by the lightning travels to the four closest sites, we calculated the distance from the lightning to each site and the time that the signal travels to each site at the speed of light c.
- (2)
- We added a random error related to the propagation distance to the arrival time calculated in step 1, the maximum error was 100 μs.
- (3)
- The arrival time calculated in step 2 was brought into the APLLN location algorithm introduced in Section 3.3 to solve the location where the lightning occurred.
- (4)
- We compared the calculated position with the actual position to obtain the calculation error.
- (5)
- We repeated the above steps 1000 times to obtain the average and standard deviation of the location error of APLLN in each grid.
4.2. Simulation Result
4.3. Comparative Analysis
5. Result and Discussion
5.1. Thunderstorm Process at 1:00~9:00 am on 26 May 2019
5.2. Comparison of Asia-Pacific Lightning Location Network (APLLN) with Advanced Direction-Time Lightning Detection System (ADTD)
5.2.1. Relative Detection Efficiency
5.2.2. Relative Detection Accuracy
5.2.3. Peak Current
5.3. Comparison with Lightning Accident
5.4. Comparison with World Wide Lightning Location Network (WWLLN)
6. Conclusions
- (1)
- It used higher sampling rate (500 kSPS), digital filtering and the Hilbert envelope method to obtain the arrival time of lightning.
- (2)
- It was based on the FPGA + ARM system, real-time storage and network transmission of lightning waveforms were facilitated to improve the research on VLF lightning location algorithms and ground-ionospheric waveguide theory.
- (3)
- It used solar power to eliminate the interference of AC (Alternating Current) power on the signal acquisition system.
- (4)
- The initial solution of lightning location was obtained by using the spherical triangle location algorithm, and the propagation velocity was introduced as an optimization factor into the Levenberg–Marquardt non-linear least square algorithm to optimize the lightning location results.
- (5)
- APLLN can achieve relatively high detection efficiency with few detection sites to save hardware resources and the number of sites.
Author Contributions
Funding
Acknowledgments
Conflicts of Interest
References
- Rakov, V.A. Electromagnetic Methods of Lightning Detection. Surv. Geophys. 2013, 34, 731–753. [Google Scholar] [CrossRef]
- Krider, E.P.; Noggle, R.C.; Uman, M.A. A Gated, Wideband Magnetic Direction Finder for Lightning Return Strokes. J. Appl. Meteorol. 1976, 15, 301–306. [Google Scholar] [CrossRef] [2.0.CO;2" target='_blank'>Green Version]
- Wu, T.; Wang, D.; Takagi, N. Lightning Mapping with an Array of Fast Antennas. Geophys. Res. Lett. 2018, 45, 3698–3705. [Google Scholar] [CrossRef]
- Rison, W.; Thomas, R.J.; Krehbiel, P.R.; Hamlin, T.; Harlin, J. A GPS-based three-dimensional lightning mapping system: Initial observations in central New Mexico. Geophys. Res. Lett. 1999, 26, 3573–3576. [Google Scholar] [CrossRef] [Green Version]
- Wang, J.; Huang, Q.; Ma, Q.; Chang, S.; He, J.; Wang, H.; Zhou, X.; Xiao, F.; Gao, C. Classification of VLF/LF Lightning Signals Using Sensors and Deep Learning Methods. Sensors 2020, 20, 1030. [Google Scholar] [CrossRef] [PubMed] [Green Version]
- Cummins, K.L.; Murphy, M.J. An Overview of Lightning Locating Systems: History, Techniques, and Data Uses, With an In-Depth Look at the U.S. NLDN. IEEE Trans. Electromagn. Compat. 2009, 51, 499–518. [Google Scholar] [CrossRef]
- Poelman, D.R.; Schulz, W.; Diendorfer, G.; Bernardi, M. European cloud-to-ground lightning characteristics. In Proceedings of the 2014 International Conference on Lightning Protection (ICLP); 2014; pp. 24–29. [Google Scholar]
- Dowden, R.L.; Brundell, J.B.; Rodger, C.J. VLF lightning location by time of group arrival (TOGA) at multiple sites. J. Atmos. Solar-Terr. Phys. 2002, 64, 817–830. [Google Scholar] [CrossRef]
- Rodger, C.J.; Brundell, J.B.; Hutchins, M.; Holzworth, R.H. The world wide lightning location network (WWLLN): Update of status and applications. In Proceedings of the 2014 XXXIth URSI General Assembly and Scientific Symposium (URSI GASS), Beijing, China, 16–23 August 2014; pp. 1–2. [Google Scholar] [CrossRef]
- Smith, D.A.; Eack, K.B.; Harlin, J.; Heavner, M.; Jacobson, A.R.; Massey, R.S.; Shao, X.M.; Wiens, K.C. The Los Alamos Sferic Array: A research tool for lightning investigations. J. Geophys. Res. Space Phys. 2002, 107, ACL 5-1. [Google Scholar] [CrossRef] [Green Version]
- Srivastava, A.; Tian, Y.; Qie, X.; Wang, N.; Sun, Z.; Yuan, S.; Wang, Y.; Chen, Z.; Xu, W.; Zhang, H.; et al. Performance assessment of Beijing Lightning Network (BLNET) and comparison with other lightning location networks across Beijing. Atmos. Res. 2017, 197, 76–83. [Google Scholar] [CrossRef]
- Wang, Y.; Qie, X.; Wang, N.; Liu, M.; Su, D.; Wang, Z.; Liu, D.; Wu, Z.; Sun, Z.; Tian, Y. Beijing Lightning Network (BLNET) and the observation on preliminary breakdown processes. Atmos. Res. 2016, 171, 121–132. [Google Scholar] [CrossRef]
- Pázman, A. Nonlinear least squares—Uniqueness versus ambiguity. Ser. Stat. 1984, 15, 323–336. [Google Scholar] [CrossRef]
- Markwardt, C.B. Non-Linear Least Squares Fitting in IDL with MPFIT. In Proceedings of the Astronomical Data Analysis Software and Systems XVIII, Quebec City, QC, Canada, 2–5 November 2009; Volume 411, pp. 251–254. [Google Scholar]
- Liu, B.; Shi, L.; Qiu, S.; Liu, H.; Dong, W.; Li, Y.; Sun, Z. Fine Three-Dimensional VHF Lightning Mapping Using Waveform Cross-Correlation TOA Method. Earth Space Sci. 2020, 7. [Google Scholar] [CrossRef] [Green Version]
- Lee, A.C.L. An experimental study of the remote location of lightning flashes using a VLF arrival time difference technique. Q. J. R. Meteorol. Soc. 1986, 112, 203–229. [Google Scholar] [CrossRef]
- Liu, Z.; Koh, K.L.; Mezentsev, A.; Enno, S.-E.; Sugier, J.; Füllekrug, M. Lightning Sferics: Analysis of the Instantaneous Phase and Frequency Inferred from Complex Waveforms. Radio Sci. 2018, 53, 448–457. [Google Scholar] [CrossRef]
- Feldman, M. Hilbert Transform, Envelope, Instantaneous Phase, and Frequency. In Encyclopedia of Structural Health Monitoring; Boller, C., Chang, F.K., Fujino, Y., Eds.; John Wiley & Sons: Hoboken, NJ, USA, 2009; pp. 1–16. [Google Scholar]
- Proctor, D.E. A hyperbolic system for obtaining VHF radio pictures of lightning. J. Geophys. Res. Space Phys. 1971, 76, 1478–1489. [Google Scholar] [CrossRef]
- Proctor, D.E. VHF radio pictures of cloud flashes. J. Geophys. Res. Space Phys. 1981, 86, 4041. [Google Scholar] [CrossRef]
- Proctor, D.E.; Uytenbogaardt, R.; Meredith, B.M. VHF radio pictures of lightning flashes to ground. J. Geophys. Res. Space Phys. 1988, 93, 12683. [Google Scholar] [CrossRef]
- Passi, R.M.; López, R.E. A parametric estimation of systematic errors in networks of magnetic direction finders. J. Geophys. Res. Space Phys. 1989, 94, 13319. [Google Scholar] [CrossRef]
- Thomas, R.J.; Krehbiel, P.R.; Rison, W.; Hunyady, S.J.; Winn, W.P.; Hamlin, T.; Harlin, J. Accuracy of the Lightning Mapping Array. J. Geophys. Res. Space Phys. 2004, 109. [Google Scholar] [CrossRef] [Green Version]
- Cummins, K.L.; Murphy, M.J.; Bardo, E.A.; Hiscox, W.L.; Pyle, R.B.; Pifer, A.E. A Combined TOA/MDF Technology Upgrade of the U.S. National Lightning Detection Network. J. Geophys. Res. Space Phys. 1998, 103, 9035–9044. [Google Scholar] [CrossRef]
- Betz, H.D.; Schmidt, K.; Laroche, P.; Blanchet, P.; Oettinger, W.P.; Defer, E.; Dziewit, Z.; Konarski, J. LINET—An international lightning detection network in Europe. Atmos. Res. 2009, 91, 564–573. [Google Scholar] [CrossRef]
- Lyu, F.; Cummer, S.A.; Solanki, R.; Weinert, J.; McTague, L.; Katko, A.; Barrett, J.; Zigoneanu, L.; Xie, Y.; Wang, W. A low-frequency near-field interferometric-TOA 3-D Lightning Mapping Array. Geophys. Res. Lett. 2014, 41, 7777–7784. [Google Scholar] [CrossRef]
- Moré, J.J. The Levenberg-Marquardt algorithm: Implementation and theory. Universitext 1978, 630, 105–116. [Google Scholar]
- Marquardt, D.W. An Algorithm for Least-Squares Estimation of Nonlinear Parameters. J. Soc. Ind. Appl. Math. 1963, 11, 431–441. [Google Scholar] [CrossRef]
- Levenberg, K. A method for the solution of certain non-linear problems in least squares. Q. Appl. Math. 1944, 2, 164–168. [Google Scholar] [CrossRef] [Green Version]
- Bitzer, P.M.; Christian, H.J.; Stewart, M.; Burchfield, J.; Podgorny, S.; Corredor, D.; Kuznetsov, E.; Franklin, V.; Hall, J. Characterization and applications of VLF/LF source locations from lightning using the Huntsville Alabama Marx Meter Array. J. Geophys. Res. Atmos. 2013, 118, 3120–3138. [Google Scholar] [CrossRef]
- Koshak, W.J.; Solakiewicz, R.J.; Blakeslee, R.J.; Goodman, S.; Christian, H.J.; Hall, J.M.; Bailey, J.C.; Krider, E.P.; Bateman, M.G.; Boccippio, D.J.; et al. North Alabama Lightning Mapping Array (LMA): VHF Source Retrieval Algorithm and Error Analyses. J. Atmos. Ocean. Technol. 2004, 21, 543–558. [Google Scholar] [CrossRef] [Green Version]
- Rodger, C.J.; Brundell, J.B.; Dowden, R.L. Location accuracy of VLF World-Wide Lightning Location (WWLL) network: Post-algorithm upgrade. Ann. Geophys. 2005, 23, 277–290. [Google Scholar] [CrossRef] [Green Version]
- Rodger, C.J.; Brundell, J.B.; Dowden, R.L.; Thomson, N.R. Location accuracy of long distance VLF lightning locationnetwork. Ann. Geophys. 2004, 22, 747–758. [Google Scholar] [CrossRef] [Green Version]
- Smith, D.A.; Heavner, M.; Jacobson, A.R.; Shao, X.M.; Massey, R.S.; Sheldon, R.J.; Wiens, K.C. A method for determining intracloud lightning and ionospheric heights from VLF/LF electric field records. Radio Sci. 2004, 39, 1–11. [Google Scholar] [CrossRef]
- Liu, F.F.; Qin, Z.L.; Zhu, B.Y.; Ma, M.; Chen, M.L.; Shen, P. Observations of ionospheric D layer fluctuations during sunrise and sunset by using time domain waveforms of lightning narrow bipolar events. Chin. J. Geophys. Chin. Ed. 2018, 61, 484–493. [Google Scholar] [CrossRef]
- Lay, E.H. WWLL global lightning detection system: Regional validation study in Brazil. Geophys. Res. Lett. 2004, 31. [Google Scholar] [CrossRef] [Green Version]
- Jacobson, A.R.; Holzworth, R.; Harlin, J.; Dowden, R.; Lay, E.H. Performance Assessment of the World Wide Lightning Location Network (WWLLN), Using the Los Alamos Sferic Array (LASA) as Ground Truth. J. Atmos. Ocean. Technol. 2006, 23, 1082–1092. [Google Scholar] [CrossRef]
- Rodger, C.J.; Werner, S.; Brundell, J.B.; Lay, E.H.; Thomson, N.R.; Holzworth, R.H.; Dowden, R.L. Detection efficiency of the VLF World-Wide Lightning Location Network (WWLLN): Initial case study. Ann. Geophys. 2006, 24, 3197–3214. [Google Scholar] [CrossRef] [Green Version]
- Abreu, D.; Chandan, D.; Holzworth, R.H.; Strong, K. A performance assessment of the World Wide Lightning Location Network (WWLLN) via comparison with the Canadian Lightning Detection Network (CLDN). Atmos. Meas. Tech. 2010, 3, 1143–1153. [Google Scholar] [CrossRef] [Green Version]
Parameters | APLLN | ADTD |
---|---|---|
Antenna type | Whip antenna (1.5m) | Magnetic loop antenna + flat plate antenna |
Received signal type | Electric field | Electric and Magnetic field |
Frequency band | VLF | VLF/LF |
Technique | TOA * | TOA+DF |
Sampling Rate | 500 kSPS | - |
Record length | 2ms | - |
Location | 2D | 3D |
Detection | CG + IC without discrimination | CG + IC |
Site | 16 | 371 |
Baseline | 800–3600 km | 100–200 km |
Peak Current Threshold (kA) | Number of Shared ADTD-APLLN Events | Number of ADTD Events | APLLN Detection Efficiency (IC+CG) (%) | Number of Shared IC Strokes | Number of IC Strokes Detected by ADTD | APLLN Detection Efficiency of IC Strokes (%) | Number of Shared CG strokes | Number of CG Strokes Detected by ADTD | APLLN Detection Efficiency of CG Strokes (%) |
---|---|---|---|---|---|---|---|---|---|
<10 | 60 | 321 | 18.69 | 31 | 148 | 20.95 | 29 | 173 | 16.76 |
10~20 | 2981 | 7235 | 41.20 | 1498 | 2987 | 50.15 | 1483 | 4248 | 34.91 |
20~30 | 4937 | 8044 | 61.37 | 1178 | 1772 | 66.48 | 3759 | 6272 | 59.93 |
30~40 | 3510 | 4431 | 79.21 | 201 | 290 | 69.31 | 3309 | 4141 | 79.91 |
40~50 | 2319 | 2376 | 97.60 | 38 | 69 | 55.07 | 2281 | 2307 | 98.87 |
50~60 | 1077 | 1126 | 95.65 | 15 | 32 | 46.88 | 1062 | 1094 | 97.07 |
60~70 | 568 | 695 | 81.73 | 10 | 23 | 43.48 | 558 | 672 | 83.04 |
70~80 | 244 | 443 | 55.08 | 13 | 40 | 32.5 | 231 | 403 | 57.32 |
>=80 | 483 | 1494 | 32.33 | 37 | 98 | 37.76 | 446 | 1396 | 31.95 |
Date | Net | Time(0.1μs) | Latitude | Longitude | Location Deviation (km) | Relative Location Deviation (km) |
---|---|---|---|---|---|---|
2019/06/11 23:22:56 | ADTD | 5,401,556 | 26.58 | 106.432 | 3.686 | - |
6,457,192 | 26.578 | 106.468 | 0.243 | - | ||
7,938,329 | 26.58 | 106.469 | 0 | - | ||
9,668,794 | 26.578 | 106.477 | 0.827 | - | ||
APLLN | 5,402,307 | 26.576 | 106.462 | 0.826 | 3.021 | |
6,457,571 | 26.546 | 106.393 | 8.457 | 8.271 | ||
7,938,663 | 26.538 | 106.48 | 4.781 | 4.781 | ||
9,669,170 | 26.553 | 106.395 | 7.956 | 8.626 | ||
2019/05/27 17:20:16 | ADTD | 1,615,869 | 22.231 | 108.847 | 0.12 | - |
APLLN | 1,616,425 | 22.226 | 108.836 | 1.355 | 1.262 |
APLLN | WWLLN | |
---|---|---|
Sites number | 16 | 12 |
Baseline (km) | 800–3600 | 1200–4500 |
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Wang, J.; Ma, Q.; Zhou, X.; Xiao, F.; Yuan, S.; Chang, S.; He, J.; Wang, H.; Huang, Q. Asia-Pacific Lightning Location Network (APLLN) and Preliminary Performance Assessment. Remote Sens. 2020, 12, 1537. https://doi.org/10.3390/rs12101537
Wang J, Ma Q, Zhou X, Xiao F, Yuan S, Chang S, He J, Wang H, Huang Q. Asia-Pacific Lightning Location Network (APLLN) and Preliminary Performance Assessment. Remote Sensing. 2020; 12(10):1537. https://doi.org/10.3390/rs12101537
Chicago/Turabian StyleWang, Jiaquan, Qiming Ma, Xiao Zhou, Fang Xiao, Shangbo Yuan, Sheng Chang, Jin He, Hao Wang, and Qijun Huang. 2020. "Asia-Pacific Lightning Location Network (APLLN) and Preliminary Performance Assessment" Remote Sensing 12, no. 10: 1537. https://doi.org/10.3390/rs12101537
APA StyleWang, J., Ma, Q., Zhou, X., Xiao, F., Yuan, S., Chang, S., He, J., Wang, H., & Huang, Q. (2020). Asia-Pacific Lightning Location Network (APLLN) and Preliminary Performance Assessment. Remote Sensing, 12(10), 1537. https://doi.org/10.3390/rs12101537