Publikationsdatum:
2015-08-11
Beschreibung:
This study focuses on the 15 May 2005 geomagnetic superstorm, and aims to investigate the global variation of positive and negative storm phases and their development. Observations are provided by a series of global total electron content (TEC) maps, and multi-instrument line plots. Coupled Thermosphere-Ionosphere-Plasmasphere electrodynamics (CTIPe) simulations are also employed. Results reveal some sunward streaming plumes of storm-enhanced density (SED) over Asia and a well-developed mid-latitude trough over North America forming isolated positive and negative storms respectively. The simultaneous development of positive and negative storms over North America is also shown. Then, some enhanced auroral ionizations maintained by strong equatorward neutral winds appeared in the depleted night-time ionosphere. Meanwhile, the northern night-time polar region became significantly depleted as the SED plume plasma could not progress further than the dayside cusp. Oppositely, a polar tongue of ionization (TOI) developed in the daytime southern polar region. According to CTIP simulations, solar heating locally maximized (minimized) over the southern (northern) magnetic pole. Furthermore, strong upward surges of molecular rich air created O/N 2 decreases both in the auroral zone and in the trough region while some SED related downward surges produced O/N 2 increases. From these results we conclude for the time period studied that 1) composition changes contributed to the formation of positive and negative storms, 2) strengthening polar convection and increasing solar heating of the polar cap supported polar TOI development, and 3) a weaker polar convection and minimized solar heating of the polar cap aided the depletion of polar plasma.
Print ISSN:
0148-0227
Thema:
Geologie und Paläontologie
,
Physik
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