HR: 08:15h
AN: SA31B-02    [Abstracts]
TI: Assimilated Low Latitude Ionosphere Variability During the First CAWSES Space Wether Campaign
AU: * Sojka, J J
EM: sojka@gaim.cass.usu.edu
AF: Center for Atmospheric and Space Sciences, Utah State University 4405 Old Main Hill, Logan, UT 84322-4405 United States
AU: Schunk, R W
EM: schunk@cc.usu.edu
AF: Center for Atmospheric and Space Sciences, Utah State University 4405 Old Main Hill, Logan, UT 84322-4405 United States
AU: Scherliess, L
EM: ludger@gaim.cass.usu.edu
AF: Center for Atmospheric and Space Sciences, Utah State University 4405 Old Main Hill, Logan, UT 84322-4405 United States
AU: Thompson, D C
EM: thompson@cc.usu.edu
AF: Center for Atmospheric and Space Sciences, Utah State University 4405 Old Main Hill, Logan, UT 84322-4405 United States
AB: The Utah State University (SUS) Global Assimilation of Ionospheric Measurements (GAIM) has been used to study the first CAWSES Space Weather Campaign period (March 25 through April 5). This period is noteworthy in two distinct ways. First, there is an extended three-day very quiet geomagnetic period, which is followed almost immediately by a marked change in the ionosphere associated with severe geomagnetic activity. GAIM, for this study, assimilated over 500 groundbased GPS TEC and 18 digisonde measurements. The background ionosphere was driven by climatology models that responded to the geomagnetic K$_{p}$ and solar F$_{10.7}$ indices. The GAIM assimilation results show that the ionosphere at low latitudes is highly responsive to (a) quiet time variability from "drivers" that are relatively unknown, and (b) during the storm from drivers assumed to be associated with high latitude auroral inputs, but again relatively unspecific. However, the strength of the assimilation approach is that the observed electron density and total electron density, when assimilated, redistributes the background model ionosphere to reveal both the quiet-time and disturbed ionospheric variability. These GAIM results will be presented with comparison to the purely climatology background.
DE: 2415 Equatorial ionosphere
DE: 2437 Ionospheric dynamics
DE: 2447 Modeling and forecasting
SC: SPA-Aeronomy [SA]
MN: 2004 AGU Fall Meeting