HR: 1340h
AN: AE23A-0843    [Abstracts]
TI: Thunderstorm Charge Studies Using a Simple Cylindrical Charge Model, Electric Field Measurements, and Lightning Mapping Observations
AU: * Krehbiel, P
EM: krehbiel@ibis.nmt.edu
AF: Langmuir Laboratory, New Mexico Institute of Mining and Technology, 801 Leroy Place, Socorro, NM 87801 United States
AU: Rison, W
EM: rison@ee.nmt.edu
AF: Langmuir Laboratory, New Mexico Institute of Mining and Technology, 801 Leroy Place, Socorro, NM 87801 United States
AU: Thomas, R
EM: thomas@nmt.edu
AF: Langmuir Laboratory, New Mexico Institute of Mining and Technology, 801 Leroy Place, Socorro, NM 87801 United States
AU: Marshall, T
EM: marshall@olemiss.edu
AF: Dept. of Physics and Astronomy, University of Mississippi, Oxford, MS 38677 United States
AU: Stolzenburg, M
EM: mstolzen@phy.olemiss.edu
AF: Dept. of Physics and Astronomy, University of Mississippi, Oxford, MS 38677 United States
AU: Winn, W
EM: winn@loon.nmt.edu
AF: Langmuir Laboratory, New Mexico Institute of Mining and Technology, 801 Leroy Place, Socorro, NM 87801 United States
AU: Hunyady, S
EM: hunyady@kestrel.nmt.edu
AF: Langmuir Laboratory, New Mexico Institute of Mining and Technology, 801 Leroy Place, Socorro, NM 87801 United States
AB: A simple cylindrical disk model has been developed to simulate the electrical structure and temporal evolution of thunderstorms. Lightning mapping observations are used to infer the heights, thicknesses, and diameters of the charge regions involved in lightning in an actual storm. The amounts of charge and the charging currents are determined by adjusting their values to replicate a) balloon-borne electric field mill (EFM) soundings through the storm and/or b) ground-based EFM observations beneath the storm. The occurrence of lightning is simulated using the breakeven field for runaway electron breakdown as a criterion for `triggering' discharges, and by then removing an adjustable fraction of charge from the appropriate charge regions. With the lightning mapping observations as a guide, the above approach allows one to quantitatively interpret space-time EFM soundings and ground EFM records in terms of charging rates, charge amounts, and instantaneous profiles of the electric field and electric potential in the storm. The `ground truth' information provided by the EFM data can also be used to infer and quantitatively estimate other charges not involved in lightning, in particular the screening charge around the top of the storm and corona charges from the ground. An interesting result of the simulations is that the upper screening charge is required to be dissipated or removed in some manner; otherwise lightning eventually occurs between it and the uppermost storm charge (e.g., between negative screening charge and upper positive charge in a normal polarity storm). In addition to raising the question as to how the screening charge is removed, the result suggests that upward jets could result from the lack of such removal or dissipation.
DE: 3324 Lightning
DE: 3337 Numerical modeling and data assimilation
DE: 3304 Atmospheric electricity
SC: Atmospheric and Space Electricity [AE]
MN: 2004 AGU Fall Meeting