Tuesday, 22 January 2008: 3:45 PM
A review of enhanced monitoring and analysis techniques to characterize lightning and transient luminous events
222 (Ernest N. Morial Convention Center)
Lightning discharges, and more recently their progeny, transient luminous events (TLEs) including sprites, halos and elves, have been investigated using a variety of remote sensing techniques spanning much of the electromagnetic spectrum. New approaches continue to be developed which in turn can further increase our understanding of the lightning discharge process and its impact upon the stratosphere and mesosphere. An overview of these emerging techniques will herein be presented. A new generation of low-cost, unintensifed CCD imagers combined with fast lenses now makes the detection of TLEs routine. An evolving cooperative network of cameras (Sprite Net) has begun to acquire TLE images from a variety of convective regimes in the previously unmonitored eastern and southern U.S. Moreover, in 2006, during the AMMA campaign, the first African sprites captured from ground-based imagers were recorded from Niamey, Niger. Many of the sprite parent CGs were also characterized by several ELF systems and the World Wide Lightning Location Network. Technological advances now also allow for acquiring color video of TLEs using much lower cost systems than previously required. The emergence of high speed imaging tools to observe both sprites and lightning is producing substantial insights into their phenomenology, and especially the role of the horizontal component of the “spider” lightning and continuing currents. As high speed imagers advance from 1000 fps to one, two and even three orders of magnitude faster, new discoveries are being made. By using systems with high precision, GPS-based time stamping, it becomes increasingly straightforward to combine and portray data sets from optical imagers, VLF receivers, ULF/ELF detectors (and determinations of charge moment change), and the NLDN CG and IC data sets. A major focus has been to acquire TLE and lightning data for storms within range of 3-D Lightning Mapping Arrays. New data compositing techniques are facilitating 2-D and 3-D reconstructions of mesoscale convective systems producing TLEs. The ability to merge datasets containing GOES IR imagery, NEXRAD Level II data, 3-D VHF lightning mapping reports, NLDN metrics and the output of a newly operational prototype national Charge Moment Change Network (CMCN) allows the creation of more robust depictions of the dynamical, microphysical and electrical structure of storms producing lightning with the characteristics to generate TLEs. Examples from 2007 storms will be presented.