HR: 13:40h
AN: AE43A-01    [Abstracts]
TI: Lightning Activity Relative to the Microphysical and Kinematic Structure of Storms during a Thunder-Snow Episode on 29-30 November 2006
AU: * Emersic, C
EM: chris.emersic@noaa.gov
AF: National Research Council and National Severe Storms Laboratory, National Weather Center (NWC) University of Oklahoma 120 David L. Boren Blvd NWC Suite 1100, Norman, OK 72072, United States
AU: MacGorman, D
EM: don.macgorman@noaa.gov
AF: National Severe Storms Laboratory, National Weather Center (NWC) University of Oklahoma 120 David L. Boren Blvd NWC Suite 1100, Norman, OK 73072, United States
AU: Schuur, T
EM: Terry.Schuur@noaa.gov
AF: Cooperative Institute for Mesoscale Meteorological Studies, University of Oklahoma and National Severe Storms Laboratory, National Weather Center (NWC) University of Oklahoma 120 David L. Boren Blvd NWC Suite 1100, Norman, OK 73072, United States
AU: Lund, N
EM: nramig@ou.edu
AF: Cooperative Institute for Mesoscale Meteorological Studies, University of Oklahoma and National Severe Storms Laboratory, National Weather Center (NWC) University of Oklahoma 120 David L. Boren Blvd NWC Suite 1100, Norman, OK 73072, United States
AU: Payne, C
EM: Clark.Payne@noaa.gov
AF: Cooperative Institute for Mesoscale Meteorological Studies, University of Oklahoma and National Severe Storms Laboratory, National Weather Center (NWC) University of Oklahoma 120 David L. Boren Blvd NWC Suite 1100, Norman, OK 73072, United States
AU: Bruning, E
EM: eric.bruning@noaa.gov
AF: Cooperative Institute for Mesoscale Meteorological Studies, University of Oklahoma and National Severe Storms Laboratory, National Weather Center (NWC) University of Oklahoma 120 David L. Boren Blvd NWC Suite 1100, Norman, OK 73072, United States
AB: We have examined lightning activity relative to the microphysical and kinematic structure of a winter thunderstorm complex (a thunder-snow episode) observed east of Norman, Oklahoma during the evening of 29-30 November 2006. Polarimetric radar provided information about the type of particles present in various regions of the storms. The Lightning Mapping Array (LMA) recorded VHF signals produced by developing lightning channels. The times of arrival of these lightning signals across the array were then used to reconstruct the location and structure of lightning, and these reconstructions were overlaid with radar data to examine the relationship between lightning properties and storm particle types. Four storms in this winter complex have been examined. It was inferred from lightning structure that, in their mature stage, all cells we examined had a positive tripole electrical structure (an upper positive charge center, a midlevel negative charge center, and a lower positive charge center). The storms began with lightning activity in the lower dipole (lower positive and midlevel negative regions), but this evolved into lightning activity throughout the tripole structure within approximately 15-20 minutes. In the longer lived storms, the mature stage lasted for approximately 1.5-2 hours. During this stage, the lower positive charge region was situated less than 5 km above ground, the midlevel negative charge region was typically above 5 km, and the upper positive charge region was located at an altitude of less than 10 km in all the storm cells analyzed. The charge regions descended over approximately the last 30 minutes of lightning activity, the lower charge regions eventually reaching ground. This resulted in the loss of the lower positive charge center and the subsequent diminishment of the lower negative charge center. Lightning initiation usually coincided with the edges of regions of high reflectivity and was coincident with the presence of graupel and ice crystals in the lower dipole. Radar data suggest that ice crystals were the dominant charge carriers in the upper positive region.
DE: 3304 Atmospheric electricity
DE: 3324 Lightning
SC: Atmospheric and Space Electricity [AE]
MN: 2007 Fall Meeting