HR: 09:30h
AN: SA31B-07    [Abstracts]
TI: Seasonal Dependence of the Low-Latitude Ionosphere Response to Magnetic Storms
AU: * Lin, C
EM: clin@ucar.edu
AF: High Altitude Observatory, NCAR, P. O. Box 3000, Boulder, CO 80307 United States
AU: * Lin, C
EM: clin@ucar.edu
AF: Institute of Space Science, National Central University, Chung-Li, 320 Taiwan
AU: Richmond, A D
EM: richmond@ucar.edu
AF: High Altitude Observatory, NCAR, P. O. Box 3000, Boulder, CO 80307 United States
AU: Liu, J
EM: jyliu@ss.ncu.edu.tw
AF: Institute of Space Science, National Central University, Chung-Li, 320 Taiwan
AU: Bailey, G J
EM: G.Bailey@sheffield.ac.uk
AF: Department of Applied Mathematics, University of Sheffield, Sheffield, S3 7RH United Kingdom
AB: We use two chains of GPS receivers in the Asian (120\deg E) and American (70\deg W) sectors to simultaneously observe the variation of the low latitude ionosphere during the disturbance periods. 10 storm events with Dst drops to less than -200 nT during 2000 $\sim$ 2003 have been monitored by the two GPS receiver chains. Large expansion of the equatorial ionization anomaly (EIA) due to the penetrating electric field is seen during the initial phase in every storm event followed by the suppression of the EIA after the storm main phase. In some events, enhanced electron densities in the EIA peaks are seen during the recovery phase. Observations also show seasonal asymmetry of the EIA densities and locations during both expanding and suppression of the EIA. We compare the GPS TEC with simulation results from the Sheffield University Plasmasphere Ionosphere Model (SUPIM) to explain the change of the low-latitude plasma transport due to the storm time electric field, neutral wind, as well as effects of storm-time changes in neutral composition.
DE: 2415 Equatorial ionosphere
DE: 2435 Ionospheric disturbances
DE: 2447 Modeling and forecasting
SC: SPA-Aeronomy [SA]
MN: 2004 AGU Fall Meeting