HR: 1340h
AN: SM13A-1187    [Abstracts]
TI: Seasonal Variations of Atmospheric Electricity Measured at Amundsen-Scott South Pole Station
AU: Reddell, B D
EM: brandon.reddell@mail.uh.edu
AF: Department of Physics, University of Houston, Houston, Tx 77204-5506 United States
AU: Benbrook, J R
EM: jrbenbrook@uh.edu
AF: Department of Physics, University of Houston, Houston, Tx 77204-5506 United States
AU: * Bering, E A
EM: Edgar.Bering@mail.uh.edu
AF: Department of Physics, University of Houston, Houston, Tx 77204-5506 United States
AU: Cleary, E N
AF: Department of Space Physics and Astronomy, Rice University, Houston, Tx 77005-1892 United States
AU: Few, A A
AF: Department of Space Physics and Astronomy, Rice University, Houston, Tx 77005-1892 United States
AB: This paper investigates seasonal variations of the vertical electric field and current density as measured at the South Pole between 1991 and 1993. After initial data reduction, a model approach was used to decouple the magnetospheric and atmospheric components of the measurements. This approach calculated and subtracted the polar-cap ionospheric potential from the measured data to obtain a signal of global tropospheric origin, in principle. The diurnal variations of the resulting data were averaged as a function of UT. These averages were calculated for the data as a whole and for the date sorted and binned by season and by magnetic activity level. The seasonally-binned average results are consistent with recent papers indicating that the electric field measurement show global convective-electrical activity to be a minimum during the northern hemisphere winter, in contradiction to the original 1929 Carnegie data. Because the electric field was a maximum during the northern hemisphere summer season, the mid-latitude regions must contribute more strongly than the tropics to global atmospheric electricity. This analysis supports the link of electrical activity to global temperature. The magnetic activity binned results suggest that the polar cap potential model used under estimates the cross polar cap potential when there is a high Kp index. This result can be explained if the model did not have equal weighting across the Kp range or if the limitation on the spherical harmonic coefficients did not give the potential at the South Pole. A complete high-latitude model is needed in order to estimate saturation of the cross-cap potential, as some theories predict.
DE: 2431 Ionosphere/magnetosphere interactions (2736)
DE: 2475 Polar cap ionosphere
DE: 2736 Magnetosphere/ionosphere interactions
DE: 2760 Plasma convection
DE: 3304 Atmospheric electricity
SC: SPA-Magnetospheric Physics [SM]
MN: 2004 AGU Fall Meeting