FORTE observations of lightning radio-frequency signatures: Capabilities and basic results
- Los Alamos National Laboratory, Los Alamos, New Mexico (United States)
The FORTE satellite, launched on August 29, 1997, carries both radio-frequency-receiver and optical (imaging and photometric) payloads for the study of lightning. The radio-frequency (RF) data for the first 7 months of operation are described, both to illustrate the satellite{close_quote}s capabilities and to explain the basic statistical findings so far. FORTE{close_quote}s multichannel RF trigger system represents a significant advance in space-based monitoring of lightning emissions. We are able to observe even rather weak and diffuse RF emissions from lightning and are no longer limited to the brightest known events, {open_quotes}transionospheric pulse pairs,{close_quotes} or TIPPs. We do see TIPPs, and we show that the FORTE observations of TIPPs are consistent only with the second pulse{close_quote}s being due to a ground reflection. We find that TIPPs are basically bimodal in character, one type having a steep roll-off of power from 38 to 130 MHz and the other being essentially flat-spectrum in that range. The steep-spectrum TIPPs cluster together in the manner of most RF emissions from lightning, while the flat-spectrum events tend to maintain a wider spacing ({gt}0.1 s) between recurrent emissions. {copyright} 1999 American Geophysical Union
- OSTI ID:
- 337607
- Journal Information:
- Radio Science, Vol. 34, Issue 2; Other Information: PBD: Mar 1999
- Country of Publication:
- United States
- Language:
- English
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