Measurements of Wideband Electric Fields and Their Derivatives in Conjunction With HF and VHF Radiation Produced by Lightning Discharges
In summer 2007, the electric field measurement station on the University of Florida campus in Gainesville, Florida, was expanded to include electric field derivative (dE/dt), high frequency (HF) and very high frequency (VHF) electric field measurements. The wideband electric field measurement system had a useful frequency bandwidth of 16 Hz to 10 MHz. The upper frequency bandwidth of the dE/dt measurement system was 17 MHz. The HF and VHF measurement systems had their center frequencies at 5 MHz (with a bandwidth of 4.7 MHz to 5.4 MHz) and 36 MHz (with a bandwidth of 34 MHz to 38 MHz), respectively. The sampling rate was 100 MHz. Over 1500 four-channel records of lightning discharges on 6 thunderstorm days were acquired. Narrow Bipolar Pulses (NBPs) and pronounced preliminary breakdown pulse trains (both followed and not followed by strokes to ground) were observed among other lightning events. The dataset also includes a few positive cloud-to-ground discharges. Examples of correlated wideband electric field, dE/dt, HF and VHF radiation records will be presented and discussed. Some lightning events produced dE/dt and VHF signatures that were characteristic of NBPs, but were not accompanied by a characteristic NBP wideband electric field waveform. At least one lightning flash (three strokes to ground followed by a cloud discharge) was also recorded at Camp Blanding, about 45 km away from Gainesville.
AGU Fall Meeting Abstracts
- Pub Date:
- December 2007
- 3304 Atmospheric electricity;
- 3324 Lightning