HR: 1340h
AN: A43C-0104    [Abstracts]
TI: Interplanetary Magnetic Field (IMF By) and Atmospheric Electric Circuit Influences on Ground Level Pressure at Vostok
AU: Burns, G B
EM: gary.burns@aad.gov.au
AF: Australian Antarctic Division, Australian Government, Channel highway, Kingston, Tas 7050 Australia
AU: * Tinsley, B A
EM: tinsley@utdallas.edu
AF: University of Texas at Dallas, North Floyd Road, Dallas, Tex 75083-0688 United States
AU: Troshichev, O A
EM: olegtro@aari.nw.ru
AF: Arctic and Antarctic Research Institute, 38 Bering Street, St Petersburg, 194175 Russian Federation
AU: Frank-Kamenetsky, A V
EM: al_frank@aari.nw.ru
AF: Arctic and Antarctic Research Institute, 38 Bering Street, St Petersburg, 194175 Russian Federation
AU: Bering, E A
EM: ebering@mail.uh.edu
AF: University of Houston, Physics Department, Houston, Tex 77204-5506 United States
AB: Automatic Weather Station (MILOS) data for the interval 2000 to 2002 are used to demonstrate that ground-level atmospheric pressure at Vostok (magnetic latitude 83.6°S) is significantly correlated with the Interplanetary Magnetic Field By component (the so-called Mansurov effect). The significant association of the daily-averaged atmospheric pressure with daily-averaged IMF By values, but not with similarly-averaged IMF Bz values, at high magnetic latitude (>80°) sites suggests that the linkage process is via the atmospheric electric circuit as IMF By controls ~86% of the daily- averaged, Weimer-modelled, ionospheric potential difference above Vostok resulting from the interaction of the solar wind and the earth's magnetosphere, while IMF Bz controls less than 2%. The interaction of the solar wind and the earth's magnetic field contributes only ~10% to the ionosphere-ground potential difference above Vostok. Globally integrated meteorological generators (thunderstorms and electrified clouds) control ~90% of the signal. For concurrent, reliable, vertical electric field measurements (2000-2001) at Vostok it is found that the vertical electric field for the preceding 4 days controls ~13% of the variations in the station-level pressure. 12UT synoptic pressure-observations at Vostok are used to extend the analysis to the 1997-2004 interval, including an additional two years (1998-1999) of vertical electric field observations. The 1998 & 1999 vertical electric field measurements also imply that the preceding four days electric field values have a significant influence on the station-level pressure, but at a lesser level of control (7%). The extended IMF By data set (1997-2004) generally supports the Mansurov effect (6 of 7 yearly data sets available show a positive IMF By and pressure association at zero lag) but concern is raised by significant acausality when varying lags are examined. Cloud cover changes associated with current flowing in the global atmospheric electric circuit have been postulated as the process leading to the Mansurov effect. Our observations support this hypothesis. The correlations of pressure with total electric field imply a teleconnection of high latitude cloud formation to tropical thunderstorm activity.
DE: 3304 Atmospheric electricity
DE: 3305 Climate change and variability (1616, 1635, 3309, 4215, 4513)
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005