Broadband RF Interferometric Mapping and Polarization (BIMAP) Observations of Mini-Discharges in Thunderstorms
Abstract
Occasional brief and small electric discharges in thunderstorms have been observed before with radio frequency lightning mapping systems. These discharges may last from a few hundred microseconds to a few milliseconds and may show some small spatial extent. In this presentation, we report detailed BIMAP observations of such mini-discharges. BIMAP is deployed at the High Altitude Water Cherenkov (HAWC) gamma-ray observatory in Mexico at 4.1-km altitude, and is significantly closer to lightning activities for overhead thunderstorms as compared to sea-level observations. In a May 20, 2018 storm, numerous mini-discharges have been observed, together with very intermittent inverted intra-cloud (IC) discharges. The mini-discharges typically last a few hundred microseconds to about a millisecond. Detailed interferometric mapping shows that the mini-discharges propagate either upward or downward, apparently due to the local electric field structure for a specific event. Correlated polarization observations show that the mini-discharges start with fast breakdown in the direction of the local electric field and gradually slow down and stop where the electric field diminishes or changes direction. Despite the briefness and small spatial extent, the mini-discharges are similar to the initiating process of otherwise normal lightning discharges.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMAE11A..04S
- Keywords:
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- 3304 Atmospheric electricity;
- ATMOSPHERIC PROCESSESDE: 3314 Convective processes;
- ATMOSPHERIC PROCESSESDE: 3324 Lightning;
- ATMOSPHERIC PROCESSESDE: 3329 Mesoscale meteorology;
- ATMOSPHERIC PROCESSES