Los Alamos Sferic Array Investigation of Lightning VLF/VHF
Phenomenology
M J Heavner,
D A Smith,
A Jacobson, A Waldrum, J Harlin, and K Eack
LAUR-00-4198
Abstract
The Los Alamos Sferic Array consists of eleven VLF electric
field change meters that have been operated continuously since Spring
1997. The primary purpose for the design and deployment of the Los
Alamos Sferic Array (LASA) has been to support observations by the
FORTE satellite, which has both VHF and optical sensors. In April
1998, five sferic array stations were located in Florida, one of the
specific purposes being to attempt coincident observations with the
Kennedy Space Center
Lightning Detection and Ranging (LDAR) system.
Prior to the 2000 North American summer, three of the LASA stations
were moved to Colorado for the purpose of conducting coincident
studies with the wide range of instruments that were part of the
Severe Thunderstorm Electrification Study (STEPS) campaign, and
specifically with the Lightning Mapping Array (LMA) operated by New
Mexico Tech.
Both the LDAR and LMA sensors record VHF
emissions associated with lightning discharge processes (at 66
MHz). The Los Alamos Sferic Array electric field change meters
record sferic (VLF) signals (between 300 Hz - 500 kHz).
Understanding the relationship between the LDAR and LMA VHF
observations and the much lower frequency lightning observations of
the Los Alamos Sferic Array provides insight into lightning discharge
processes, and specifically into interpretation of coincident FORTE
(VHF) and National Lightning Detection Network (VLF) observations
(also presented at Fall AGU 2000).
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