HR: 0830h
AN: AE21A-1103    [PDF]
TI: Propagation Speeds of Lightning Leaders Throughout an Entire Flash Using 10 $\mu$s Time Resolution 3D Mapping Data.
AU: * Behnke, S A
EM: sbehnke@nmt.edu
AF: Geophysical Research Center, New Mexico Institute of Mining and Technology, Socorro, NM 87801
AU: Thomas, R J
EM: thomas@nmt.edu
AF: Geophysical Research Center, New Mexico Institute of Mining and Technology, Socorro, NM 87801
AU: Krehbiel, P
EM: krehbiel@ibis.nmt.edu
AF: Geophysical Research Center, New Mexico Institute of Mining and Technology, Socorro, NM 87801
AU: Rison, W
EM: rison@arctic.nmt.edu
AF: Geophysical Research Center, New Mexico Institute of Mining and Technology, Socorro, NM 87801
AB: The Lightning Mapping Array normally records lightning radiation sources in each 80 $\mu$s time interval but can be operated in a high time resolution mode where sources can be located as often as every 10 $\mu$s. The 10 $\mu$s data can show very detailed structure and development of the breakdown channels. Using the 10 $\mu$s data, we have performed a detailed analysis of several flashes, including intracloud, cloud-to-ground, and bolt-from-the-blue type discharges, in which we isolated most of the branches and made cubic spline fits to the x, y, and z values versus time. From the analyses, we have characterized the evolution of both the individual branches and of the overall flash. For an individual branch, we often see the speed of the branch decreasing with time, reaching some minimum speed, usually between 4 - $8\times 10^4$ m/s, at which the branch expires. Overall, we have found that typical branch speeds range between $4\times 10^4$ and $2\times 10^5$ m/s.
DE: 3304 Atmospheric electricity
DE: 3324 Lightning
SC: Atmospheric and Space Electricity [AE]
MN: 2003 Fall Meeting