HR: 08:30h
AN: SA31B-03 INVITED     [Abstracts]
TI: The climatology of low-latitude ionospheric densities and zonal drifts from IMAGE-FUV.
AU: * Immel, T J
EM: immel@ssl.berkeley.edu
AF: University of California Berkeley, Space Science Laboratory, Berkeley, CA 94720 United States
AU: Sagawa, E
EM: esagawa@nict.go.jpan
AF: National Institute of Information and Communications Technology, 4-2-1 Nukuikita-machi, Koganei-si, Tokyo, 184-8795 Japan
AU: Frey, H U
EM: hfrey@ssl.berkeley.edyou
AF: University of California Berkeley, Space Science Laboratory, Berkeley, CA 94720 United States
AU: Mende, S B
EM: mende@ssl.berkeley.edyou
AF: University of California Berkeley, Space Science Laboratory, Berkeley, CA 94720 United States
AU: Patel, J
EM: jp83@ssl.berkeley.edyou
AF: University of California Berkeley, Space Science Laboratory, Berkeley, CA 94720 United States
AB: The IMAGE satellite was the first dedicated to magnetospheric imaging, but has also provided numerous images of the nightside ionosphere with its Far-Ultraviolet (FUV) spectrographic imager. Nightside emissions of O I at 135.6-nm originating away from the aurora are due to recombination of ionospheric O$^{+}$, and vary in intensity with (O$^{+}$)$^{2}$. IMAGE-FUV, operating in a highly elliptical orbit with apogee at middle latitudes and $>$7 Re altitude, measures this emission globally with 100-km resolution. During each 14.5 hour orbit, IMAGE-FUV is able to monitor nightside ionospheric densities for up to 6-7 hours. Hundreds of low-latitude ionospheric bubbles, their development and drift speed, and a variety of other dynamical variations in brightness and morphology of the equatorial anomalies have been observed during this mission. Furthermore, the average global distribution of low-latitude ionospheric plasma densities can be determined in 3 days. Imaging data collected from February through June of 2002 are used to compile a dataset containing a variety of parameters (e.g., latitude and brightness of peak plasma density, zonal bubble drift speed) which can be drawn from for climatological studies. Recent results indicate that the average ground speed of low-latitude zonal plasma drifts vary with longitude by up to 50%, and that a periodic variation in ionospheric densities with longitude suggests the influence of a lower-thermospheric non-migrating tide with wave number = 4 on ionospheric densities. An excellent correlation between zonal drift speed and the magnetic storm index Dst is also found.
DE: 2415 Equatorial ionosphere
DE: 2431 Ionosphere/magnetosphere interactions (2736)
DE: 2437 Ionospheric dynamics
DE: 0310 Airglow and aurora
SC: SPA-Aeronomy [SA]
MN: 2004 AGU Fall Meeting