Physics
Scientific paper
May 2005
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005jgra..11005309l&link_type=abstract
Journal of Geophysical Research, Volume 110, Issue A5, CiteID A05309
Physics
7
Atmospheric Composition And Structure: Thermosphere: Composition And Chemistry, Atmospheric Processes: Thermospheric Dynamics (0358), Ionosphere: Ionospheric Storms (7949), Magnetospheric Physics: Magnetic Storms And Substorms (7954), Ionosphere: Ionosphere/Atmosphere Interactions (0335)
Scientific paper
The two-dimensional structure of thermospheric neutral composition, specifically, the atomic oxygen to molecular nitrogen column density ratio, [O/N2], is studied during the 17-24 April 2002 geomagnetic storms to understand the cause of ionospheric storms in regions equatorward of the auroral oval on an instantaneous large scale. The [O/N2] ratio is derived from the dayglow emission ratio of O I 1356 Å to N2 Lyman-Birge-Hopfield (1600-1800 Å) acquired from the Polar ultraviolet imager (UVI) and the total electron content (TEC), which is used to infer ionospheric storms, 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 after the development of the storms. 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, long-lived positive storm effects predicted by empirical and general circulation models were not observed. In fact, there was no noticeable change in [O/N2]. The TEC data also showed no noticeable change, except a few ``short-lived,'' localized positive TEC perturbations. For this particular event, the equatorward expansion of the decreased [O/N2] at the onset of the first storms was estimated to be more than 600 m/s, much faster than the typical thermospheric wind, and reached ~30°N in 2 hours much equatorward (>25° MLAT) beyond the auroral electrojets. This result suggests that midlatitude (negative) ionospheric storms are caused by direct equatorward penetration of a reduced thermospheric [O/N2], at least during the first few hours of storms.
Anderson Benjamin J.
Liou Kan
Meng Ching I.
Newell Patrick T.
Zanetti L.
No associations
LandOfFree
Neutral composition effects on ionospheric storms at middle and low latitudes does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Neutral composition effects on ionospheric storms at middle and low latitudes, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Neutral composition effects on ionospheric storms at middle and low latitudes will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1598916