HR: 1340h
AN: SA33A-1138 [Abstracts]
TI: Neutral composition effects on negative ionospheric
storms at middle and low latitudes: Polar ultraviolet
imager observations
AU: * Wu, C
EM: wuc@cspar.uah.edu
AF: CSPAR/UAH, University of Alabama in Huntsville, Huntsville, AL 35899
United States
AU: Liou, K
EM: kan.liou@jhuapl.edu
AF: JHU/APL, 11100 Johns Hopkins Road, Laurel, MD 20723
United States
AU: Meng, C
EM: ching.meng@jhuapl.edu
AF: JHU/APL, 11100 Johns Hopkins Road, Laurel, MD 20723
United States
AU: Newell, P T
EM: patrick.newell@jhuapl.edu
AF: JHU/APL, 11100 Johns Hopkins Road, Laurel, MD 20723
United States
AB:
The April 17-24 geomagnetic storm event is studied to understand the
relationship between neutral composition (specifically, atomic
oxygen to molecular nitrogen column density ratios, O/N2) and total
electron content (TEC) on an instantaneous global scale on dayside.
The O/N2 column density ratio is derived from the dayglow emissions
of OI 135.6 nm and N2 Lyman-Birge-Hopfield (160-180 nm) acquired
from the ultraviolet imager (UVI) aboard the Polar satellite and the total
electron content is derived from the phase delays of dual-band global
positioning satellite (GPS) accumulated around the globe.
It is found that the regions of decreasing O/N2 generally coincided
with the regions of depleted TEC during and the after the development
of the storm. This is consistent with previous theoretical and
experimental analysis in which composition changes play a major
role in the negative ionospheric storm effects. At lower latitudes
there was no noticeable change in O/N2. The TEC data also
showed no noticeable change, except a few "short-lived," localized
positive TEC effects. Long duration positive storm effects,
frequently predicted by general circulation models, are not observed.
Detailed results will be presented and their implication will be discussed.
DE: 2435 Ionospheric disturbances
DE: 2443 Midlatitude ionosphere
DE: 0355 Thermosphere--composition and chemistry
SC: SPA-Aeronomy [SA]
MN: 2004 AGU Fall Meeting