HR: 16:45h
AN: SA24A-04    [Abstracts]
TI: Ionospheric positive and negative storm phases: Dependence on the vertical ion transport, tongue of ionization and neutral advection
AU: * Deng, Y
EM: ydeng@umich.edu
AF: University of Michigan, 2455 Hayward Avenue, Ann Arbor, MI 48109-2143 United States
AU: Ridley, A J
EM: ridley@umich.edu
AF: University of Michigan, 2455 Hayward Avenue, Ann Arbor, MI 48109-2143 United States
AB: During storm times, complex disturbances in the ionosphere-thermosphere can cause both increases and decreases in the F2 peak electron density, which are ionospheric positive and negative storm phases, respectively [Lu et al.(2001)]. The electron density profile is very important, possibly changing the total electron content (TEC), and hence affecting GPS measurements. The change of electron density can also feed-back to the Joule heating. While it is understood that the coexistence of many effects causes the variety of forms of ionosphere, these effects have not been thoroughly quantified. Many studies have been done about the influence of horizontal ion, neutral transport and neutral composition to the ionosphere, but few studies have investigated the role of vertical ion transport to the ionospheric positive/negative storm and altiudedependent changes of neutral and ion densities. We use the Global Ionosphere-Thermosphere Model (GITM) to simulate the ionospheric reaction to a simple step change of the high latitude forcing terms. First, we present the altitude distribution of electron density variations. Then, by turning on and off some parameters, we can seperate the effects of different factors. We are able to quantify the impact of vertical ion transport, how much change is due to the tongue of ionization and neutral tongue, and what the correlation between O/N2 and electron density is in non-steady state situation.
DE: 2427 Ionosphere/atmosphere interactions (0335)
DE: 2431 Ionosphere/magnetosphere interactions (2736)
DE: 2441 Ionospheric storms (7949)
DE: 2475 Polar cap ionosphere
DE: 7959 Models
SC: SPA-Aeronomy [SA]
MN: Fall Meeting 2005