HR: 09:15h
AN: AE41A-06    [Abstracts]
TI: Evolution of radar structure, total lightning, and sprite production in an Oklahoma mesoscale convective system on 20 June 2007
AU: * Rutledge, S
EM: rutledge@atmos.colostate.edu
AF: Colorado State University, 200 W Lake St, Fort Collins, CO 80523,
AU: Lyons, W
EM: walyons@frii.com
AF: FMA Research, Inc., 46050 Weld County Rd 13, Fort Collins, CO 80524,
AU: Lang, T
EM: tlang@atmos.colostate.edu
AF: Colorado State University, 200 W Lake St, Fort Collins, CO 80523,
AU: Meyer, J
EM: walyons@frii.com
AF: University of Northern Colorado, 501 20 St., Greeley, CO 80639,
AU: Cummer, S
EM: cummer@ee.duke.edu
AF: Duke University, Box 90291, Durham, NC 27708,
AB: On 20 June 2007 a classic leading-line/trailing-stratiform mesoscale convective system (MCS) passed through central Oklahoma. This MCS consisted of two bowed convective lines that merged around 0600 UTC. Between 0000 and 0800 UTC, the storm produced 13,450 positive cloud-to-ground flashes (+CGs; > 10 kA) and 205,736 negative CGs (> 10 kA), and over 250 sprites, halos, and elves were captured on camera at ranges out to 814 km from Yucca Ridge, Colorado. Approximately 50 of these transient luminous events (TLEs) were within 2-D range (~200 km) of the Oklahoma Lightning Mapping Array (LMA). While negative CGs dominated the storm, the census of CGs with peak currents > 75 kA was nearly even, 712 positive to 725 negative. The large positives were mostly confined to the trailing stratiform and were associated with large impulse charge moment changes and TLE production. During the peak TLE production time the cloud canopy area of -50 deg C or colder was 560,000 km2. The evolution of the radar structure of this storm is being studied using 3-D composites developed from multiple radars covering Oklahoma, while 2-D and 3-D total lightning production is being examined using Oklahoma LMA data. In addition, a database of optically detected sprites linked to their parent positive CG discharges and impulse charge moment changes has been developed. Using these data, the possible dependence of sprite generation on the vertical structure of the stratiform region, as well as MCS organization, is being examined. In addition, the relationship between MCS electrical morphology (e.g., arrangement of charge layers in the stratiform region) and sprite production is being examined. In particular, one question being addressed is: How does the probability of a stratiform +CG to produce a sprite depend on the initiation location of the +CG, as well as the vertical location of the positive charge layer it is tapping? Initial results of this study will be presented.
DE: 3304 Atmospheric electricity
DE: 3314 Convective processes
DE: 3324 Lightning
DE: 3329 Mesoscale meteorology
DE: 3394 Instruments and techniques
SC: Atmospheric and Space Electricity [AE]
MN: 2007 Fall Meeting