HR: 11:00h
AN: AE41B-03    [PDF]
TI: Ongoing Studies of the Characteristics of Storms and Lightning Discharges Which Do and Do Not Produce Sprites
AU: * Lyons, W A
EM: walyons@frii.com
AF: FMA Research, Inc., 46050 Weld County Road 13, Fort Collins, CO 80524 United States
AU: Cummer, S A
EM: cummer@ee.duke.edu
AF: Duke University, Dept. of Electrical and Computer Engineering, Durham, NC 90291 United States
AU: Stanley, M A
EM: stanleym@lanl.gov
AF: Mark A. Stanley, Los Alamos National Laboratory, Los Alamos, NM 87545 United States
AB: Within a year after the first intentional ground and aircraft monitoring of sprites (1993), it had become apparent that this class of mesospheric transient luminous event was almost uniquely associated with positive polarity cloud-to-ground lightning strokes (+CGs). Yet not all +CGs, even those with high peak currents, produce sprites. Moreover, sprite parent +CGs (SP+CGs) tend to occur only in certain types of convective storm systems. On the U.S. High Plains, the SP+CGs are most common in the stratiform precipitation regions of mature mesoscale convective systems (MCSs) larger than 10-20x10**4 km**2. The summer 2000 Severe Thunderstorm Electrification and Precipitation Study (STEPS) produced the most complete database of coordinated low-light television (LLTV), 3-D lightning mapping array (LMA) and remote ELF transient data available to date. A major question is whether large charge moment changes are both a necessary and a sufficient condition for sprites? This presentation presents the results of a reanalysis of the STEPS database which, aided by ELF charge moment change estimates, has revealed substantially more events than in the original catalog. Particular attention is paid to charge moment changes in three major classes of storms, (1) MCSs with many SP+CGs in the stratiform region, (2) supercells with only sporadic sprite events during restricted portions of their life cycle, and (3) MCSs and supercell storms which, in spite of many +CGs, produce no transient luminous events. In addition, the characteristics of continuing currents in High Plains lightning discharges monitored using high speed video cameras (1000 fps) is compared with ELF/ULF measurements (Courtesy: Martin Fullekrug). Additional observations of sprites and elves were obtained during summer 2003, in conjunction with an upgraded Duke University ELF transient monitoring system. Some initial results will be presented.
DE: 2411 Electric fields (2712)
DE: 3304 Atmospheric electricity
DE: 3324 Lightning
SC: Atmospheric and Space Electricity [AE]
MN: 2003 Fall Meeting