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Ann. Geophys., 22, 3241-3250, 2004
www.ann-geophys.net/22/3241/2004/
© European Geosciences Union 2004
Magnetic storm-induced enhancement in neutral composition at low latitudes as inferred by O(1D) dayglow measurements from Chile
D. Pallamraju1, S. Chakrabarti1, and C. E. Valladares2
1Center for Space Physics, Boston University, 725 Commonwealth Avenue, Boston, MA, 02215, USA
2Boston College, Institute of Space Research, 140 Commonwealth Avenue, Chestnut Hill, MA, 02467, USA
Abstract. We describe the effect of the 6 November 2001 magnetic storm on the
low latitude thermospheric composition. Daytime red line (OI 630.0nm)
emissions from Carmen Alto, Chile showed anomalous 2-3 times larger
emissions in the morning (05:30-08:30 Local Time; LT) on the disturbed day
compared to the quiet days. We interpret these emission enhancements to be
caused due to the increase in neutral densities over low latitudes, as a
direct effect of the geomagnetic storm. As an aftereffect of the geomagnetic
storm, the dayglow emissions on the following day show gravity wave features
that gradually increase in periodicities from around 30min in the
morning to around 100min by the evening. The integrated dayglow
emissions on quiet days show day-to-day variabilities in spatial structures
in terms of their movement away from the magnetic equator in response to the
Equatorial Ionization Anomaly (EIA) development in the daytime. The EIA
signatures in the daytime OI 630.0nm column-integrated dayglow emission
brightness show different behavior on days with and without the post-sunset
Equatorial Spread F (ESF) occurrence.
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