HR: 1330h
AN: AE42A-0786    [PDF]
TI: Stratospheric Electric Field and Conductivity Measurements Above Thunderstorms: Implications for Sprite Models
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: 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: msato@pat.geophys.tohoku.ac.jp
AF: Department of Geophysica, Graduate School of Science, Tohoku University, Aramaki-Aoba, Sendai, 980-8578 Japan
AB: Electric fields and conductivity were measured in the stratosphere ($32$-$34$~km altitude) above thunderstorms as part of the Sprite Balloon Campaign 2002-2003 in southeastern Brazil. During the two balloon flights, the payloads measured hundreds of electric field transients, some as large as $130$~V/m, correlated with lightning events. Also, conductivity variations over thunderstorms of at least a factor of two different from the fair weather values were measured. Since optical verification of sprites was not achieved during these flights and recent studies (Hu et al. 2002) have found that the probability of sprite production is proportional to the charge moment of the corresponding positive cloud-to-ground (+CG) stroke, we rely on charge moment estimates from remote ELF observations in Onagawa, Japan and Syowa, Antarctica to indicate possible sprite events. Here we present a detailed study of several nearby ($<60$~km) +CG strokes indicated by the ELF charge moment estimate to be probable sprite generators. By using a quasi-static electric field model (Pasko et al. 1997), we show how these large field changes correlated with +CG strokes, along with varying conductivity over thunderstorms, may provide the necessary conditions for sprite development.
UR: http://www.ess.washington.edu/Space/AtmosElec/home.html
DE: 3304 Atmospheric electricity
DE: 3324 Lightning
DE: 3334 Middle atmosphere dynamics (0341, 0342)
DE: 3362 Stratosphere/troposphere interactions
SC: Atmospheric and Space Electricity [AE]
MN: 2003 Fall Meeting