Analysis of lightning electromagnetic field propagation in mountainous terrain and its effects on ToA-based lightning location systems

Li, Donshuai (Collaborative Innovation Center on Forecast and evaluation of Meteorological Disasters, CMA Key Laboratory for Aerosol-Cloud-Precipitation, Nanjing University of Information Science and Technology, Nanjing, China ; Electromagnetic Compatibility Laboratory, swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland) ; Azadifar, Mohammad (Electromagnetic Compatibility Laboratory, swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland) ; Rachidi, Farhad (Electromagnetic Compatibility Laboratory, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland) ; Rubinstein, Marcos (School of Management and Engineering Vaud, HES-SO // University of Applied Sciences Western Switzerland) ; Diendorfer, Gerhard (Department Austrian Lightning Detection and Information System, OVE Service GmbH, Vienna, Austria) ; Sheshyekani, Keyhan (Electrical and Computer Engineering Department, Shahid Beneshti University, Tehran, Iran) ; Zhang, Qilin (Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, CMA Key Laboratoryfor Aerosol-Cloud-Precipitation, Nanjing University of Information Science and Technology, Nanjing, China) ; Wang, Zhenhui (Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, CMA Key Laboratoryfor Aerosol-Cloud-Precipitation, Nanjing University of Information Science and Technology, Nanjing, China)

In this paper, we analyze the propagation effects on lightning‐radiated electromagnetic fields over mountainous terrain by using a three‐dimensional (3‐D) finite difference time domain (FDTD) method. We also discuss the time delay error in the time‐of‐arrival (ToA) technique currently used to locate lightning in detection networks, specifically. Furthermore, the accuracy of different approximate methods presented in the literature is discussed and tested by using our 3‐D FDTD method. It is found that (1) the time delays and amplitudes of the lightning‐radiated electromagnetic fields can be significantly affected by the presence of a mountainous terrain and associated diffraction phenomena; (2) for a finitely conducting ground, the time delay shows a slight increase with the increase of the observation distance, but the time delay resulting from the finite ground conductivity appears to be smaller than that caused by the mountainous terrain; and (3) the timing error associated with the ToA technique depends on the threshold times. Threshold times of 10% and 20% of the peak provide very similar results compared to those corresponding to the peak of the first derivative of the magnetic field, and the threshold time exceeds 50% of the initial rising amplitude of the signal. Furthermore, we have assessed the accuracy of two simplified methods (terrain‐envelope method and tight‐terrain fit method) to account for the time delays resulting from the propagation in a mountainous terrain. It is found that both methods result in time delays that are in reasonable agreement but always overestimating the results obtained using the full‐wave 3‐D FDTD approach for the perfectly conducting ground. These two methods represent interesting alternatives to account for the time delay over a nonflat terrain using the terrain model.


Article Type:
scientifique
Faculty:
Ingénierie et Architecture
School:
HEIG-VD
Institute:
IICT - Institut des Technologies de l'Information et de la Communication
Date:
2016-01
Pagination:
17 p.
Published in:
Journal of Geophysical Research: Atmospheres
Numeration (vol. no.):
2016, vol. 121, no. 2, pp. 895-911
DOI:
ISSN:
2169-897X
Appears in Collection:



 Record created 2020-10-20, last modified 2020-10-27

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