On the Accuracy of Ray-Theory Methods to Determine the Altitudes of Intracloud Electric Discharges and Ionospheric Reflections : Application to Narrow Bipolar Events
©2020. The Authors.
| Veröffentlicht in: | Journal of geophysical research. Atmospheres : JGR. - 1998. - 125(2020), 9 vom: 16. Mai, Seite e2019JD032099 |
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| 1. Verfasser: | |
| Weitere Verfasser: | , , , , , |
| Format: | Online-Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2020
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| Zugriff auf das übergeordnete Werk: | Journal of geophysical research. Atmospheres : JGR |
| Schlagworte: | Journal Article Earth‐Ionosphere WaveGuide (EIWG) VLF/LF finite‐difference time domain (FDTD) narrow bipolar events (NBEs) |
| Zusammenfassung: | ©2020. The Authors. Narrow bipolar events (NBEs) (also called narrow bipolar pulses [NBPs] or compact intracloud discharges [CIDs]) are energetic intracloud discharges characterized by narrow bipolar electromagnetic waveforms identified from ground-based very low frequency (VLF)/low-frequency (LF) observations. The simplified ray-theory method proposed by Smith et al. (1999, https://doi.org/10.1029/1998JD200045; 2004, https://doi.org/10.1029/2002RS002790) is widely used to infer the altitude of intracloud lightning and the effective (or virtual) reflection height of the ionosphere from VLF/LF signals. However, due to the large amount of high-frequency components in NBEs, the propagation effect of the electromagnetic fields for NBEs at large distance depends nontrivially on the geometry and the effective conductivity of the Earth-ionosphere waveguide (EIWG). In this study, we investigate the propagation of NBEs by using a full-wave Finite-Difference Time-Domain (FDTD) approach. The simulated results are compared with ground-based measurements at different distances in Southern China, and we assess the accuracy of the simplified ray-theory method in estimating the altitude of the NBE source and the effective reflection height of the ionosphere. It is noted that the evaluated NBE altitudes have a slight difference of about ±1 km when compared with the full-wave FDTD results, while the evaluated ionospheric reflection heights are found to be bigger than those obtained from FDTD model by about 5 km |
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| Beschreibung: | Date Revised 29.03.2024 published: Print-Electronic Citation Status PubMed-not-MEDLINE |
| ISSN: | 2169-897X |
| DOI: | 10.1029/2019JD032099 |