GUVI/TIMED Observations of the auroral inputs and thermospheric response during
the October and  November 2003 Superstorms

Y. Zhang, L.J. Paxton, J.U. Kozyra, R. DeMajistre, H. Kil, D. Morrison, 
B. Wolven, P.C. Brandt, D.G. Mitchell, and T. Talaat


The GUVI instrument on the NASA TIMED Mission observes the ionosphere and
thermosphere as well as the auroral inputs. In this  paper we explore the
connection between the geospace environment and the Earth's atmosphere - in
particular we follow the particle chain. We report evidence between a direct
coupling between the ring current and the upper atmosphere. Observations by GUVI
show rapid (~hour) increases in the 1356 A brightness over all latitude in the
nightside ionosphere. The increases are simultaneous with substorm injections
observed by the High Energy Neutral Atom (HENA) imager on board the IMAGE
satellite. These observations suggest that energetic (10-100 keV) Oxygen atoms,
produced by charge exchange of the O+ in the ring current, precipitate directly
from the ring current region onto the upper atmosphere. The local solar time
dependent distribution of the neutrals is also altered by the deposition of
electrons and protons, energized in the magnetosphere, at auroral latitudes. The
aurora extended well below 40 deg north latitude at times. We compare the
average quiet-time behavior of the upper atmosphere, as derived from GUVI
observations, to that observed during these storms. We find that there are very
large depletions in atomic oxygen that extend nearly to the magnetic equator.
These  O depletions, which should result in a negative ionospheric storm, are
also observed in GPS TEC measurements. We also find evidence for localized O
density enhancements and/or the uplift of the ionosphere by the neutral winds
and electric fields which lead to a positive ionospheric storm. We also will
show results from our studies of the ionosphere: we compare the seasonal
distribution of the ionosphere (its total density, peak density, and peak
height) for quiet and disturbed conditions. Our model simulations indicate that
we are seeing a direct manifestation of the role of the storm induced winds and
penetration electric fields in the Earth's upper atmosphere.

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Presentation, Fall A.G.U. Meeting, San Francisco, CA, 13-17 December 2004