HR: 09:15h
AN: SA41A-05    [Abstracts]
TI: Ionospheric Response During Four Intense Geomagnetic Storms: Similarities and Differences
AU: * Mannucci, A J
EM: tony.mannucci@jpl.nasa.gov
AF: Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, United States
AU: Tsurutani, B T
EM: Bruce.T.Tsurutani@jpl.nasa.gov
AF: Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, United States
AU: Crowley, G
EM: gcrowley@astraspace.net
AF: Atmospheric and Space Technology Research Associates, 11118 Quail Pass, San Antonio, TX 78249, United States
AU: Verkhoglyadova, O P
EM: olga.verkhoglyadova@ucr.edu
AF: University of California, Riverside, Physics 2153 University of California, Riverside, CA 92521, United States
AB: Large magnitude and hemispheric-scale increases in ionospheric plasma content are observed for daytime local times during intense geomagnetic storms. Ionospheric increases during the main phase of geomagnetic storms were identified many years ago and categorized as the "positive phase" ionospheric response. This talk will explore what we can learn using satellite data and distributed ground-based measurements, to understand the geoeffective processes at work in creating the positive phase for intense storms. The importance of electric fields penetrating to low latitudes on the dayside has received a great deal of attention recently, and is leading to revised theoretical and modeling constructs to account for the observations in a quantitative manner. We will present ground and space-based Global Positioning System (GPS) electron content data for four storms and analyze the data in light of the upstream conditions with a common epoch analysis. Modeling studies of the storm-time ionospheric behavior will be shown, using the ASPEN-TIMEGCM fully-coupled thermosphere- ionosphere (T-I) model with low-latitude electrodynamics. The ASPEN-TIMEGCM model contains storm-time effects such as winds and the resulting dynamo electric fields, but penetration E-fields including shielding are not currently included. The model runs are driven by carefully reconstructed high latitude time-dependent drivers based in part on the AMIE high latitude electrodynamics model. The time history of a modeled storm will be compared with observations. We will highlight outstanding science questions that are revealed in this study.
DE: 2431 Ionosphere/magnetosphere interactions (2736)
DE: 2441 Ionospheric storms (7949)
DE: 2447 Modeling and forecasting
SC: SPA-Aeronomy [SA]
MN: 2007 Joint Assembly