HR: 11:20h
AN: AE52A-04    [Abstracts]
TI: Lightning-Driven Electric Fields in the Stratosphere: Comparisons Between In-Situ Measurements and a Quasi-Electrostatic Field Model
AU: * Thomas, J N
EM: jnt@u.washington.edu
AF: Department of Earth and Space Sciences, University of Washington, Box 351310, Seattle, WA 98195-1310 United States
AU: Holzworth, R H
EM: bobholz@ess.washington.edu
AF: Department of Earth and Space Sciences, University of Washington, Box 351310, Seattle, WA 98195-1310 United States
AU: McCarthy, M P
EM: mccarthy@ess.washington.edu
AF: Department of Earth and Space Sciences, University of Washington, Box 351310, Seattle, WA 98195-1310 United States
AU: Roy, N G
EM: nimisha@u.washington.edu
AF: Department of Earth and Space Sciences, University of Washington, Box 351310, Seattle, WA 98195-1310 United States
AU: Solorzano, N N
EM: natalia@dge.inpe.br
AF: Department of Earth and Space Sciences, University of Washington, Box 351310, Seattle, WA 98195-1310 United States
AU: Pinto, O
EM: osmar@dge.inpe.br
AF: Instituto Nacional de Pesquisas Espaciais, INPE, Ave dos Astronautas, 1758 CEA/DGE, Sao Jose dos Campos, SP 12227-010 Brazil
AU: Sato, M
EM: mitsu-sato@riken.jp
AF: Computational Astrophysics Lab, RIKEN, 2-1 Hirosawa, Wako, 351-0198 Japan
AB: During the Sprite Balloon Campaign in southeastern Brazil (December 6-7, 2002), 38 electric field changes greater than $10$~V/m, correlated with cloud-to-ground and intra-cloud lightning, were measured above $30$~km in altitude in the stratosphere. These electric field signatures are compared directly to an axi-symmetric quasi-electrostatic field (QSF) model developed by the authors and based on the model of Pasko et al. '97. Both the amplitude and the relaxation time of the lightning-driven electric fields are compared to this QSF model at the exact location of the in-situ balloon-borne measurements. The Brazilian Integrated Network (BIN), a regional ground-based lightning detection network that covers the southeast of Brazil, provides lightning location and peak current values for cloud-to-ground strokes, while remote extremely low frequency (ELF) magnetic field measurements from Japan and Antarctica provide charge moment estimates. These network and remote measurements, along with in-situ measurements of the conductivity by the Sprite flight 1 balloon payload, provide realistic input parameters to this QSF model. The in-situ electric field measurements are compared to the output of the QSF model for various cloud charge distributions and atmospheric conductivity profiles. When the electric field measurements agree well with the QSF model, the model can predict the electric field signature everywhere in the stratosphere and mesosphere, including sprite initiation altitudes. Thus, by utilizing in-situ electric field and conductivity measurements, local lightning network data, remote ELF measurements, and a QSF model of the lightning discharge, we are able to predict the amplitude and relaxation time of the electric field at sprite altitudes.
UR: http://www.ess.washington.edu/students/jnt/
DE: 6904 Atmospheric propagation
DE: 3324 Lightning
DE: 3332 Mesospheric dynamics
DE: 3304 Atmospheric electricity
DE: 0342 Middle atmosphere--energy deposition
SC: Atmospheric and Space Electricity [AE]
MN: 2004 AGU Fall Meeting