Low-latitude ionospheric-thermospheric response to storm time electrodynamical coupling between high and low latitudes

Bagiya, Mala S. ; Iyer, K. N. ; Joshi, H. P. ; Thampi, Smitha V. ; Tsugawa, Takuya ; Ravindran, Sudha ; Sridharan, R. ; Pathan, B. M. (2011) Low-latitude ionospheric-thermospheric response to storm time electrodynamical coupling between high and low latitudes Journal of Geophysical Research, 116 (A1). A01303_1-A01303_17. ISSN 0148-0227

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Official URL: http://www.agu.org/pubs/crossref/2011/2010JA015845...

Related URL: http://dx.doi.org/10.1029/2010JA015845


Using multi-instrumental and multistation data, we present low-latitude ionospheric-thermospheric behavior during the geomagnetic storm of 15 May 2005. The diurnal pattern of total electron content (TEC) at a chain of equatorial to low-latitude stations shows strong positive ionospheric storm on 15 May. Latitudinal variation of TEC shows development of strong equatorial ionization anomaly (EIA) on the same day. Evidence, in terms of equatorial electrojet (EEJ) and magnetogram signatures, is presented for the prompt penetration of interplanetary electric field (IEF) as the cause of the positive ionospheric storm. Consequent to the storm time circulation resulting from the extra energy deposition via Joule heating over high latitudes, compositional changes occur in the global thermosphere. TEC enhancements on 16 May are attributed to enhancement of atomic oxygen at equatorial and low latitudes and the negative ionospheric storm on 17 May observed beyond certain low latitudes is explained in terms of enhancement of molecular species because of the storm time neutral composition changes. Strong ESF plume structures on range time intensity (RTI) map and L-band scintillation and TEC depletions in GPS measurements are observed in the longitude sectors where the local time of sudden storm commencement (SSC) falls after the post sunset hours. The ionospheric zonal electric fields are altered by the combined effects of eastward disturbance dynamo electric fields and direct prompt penetration of eastward electric fields associated with the northward turning of interplanetary magnetic field (IMF) Bz leading to subsequent development of ESF after midnight.

Item Type:Article
Source:Copyright of this article belongs to American Geophysical Union.
Keywords:Ionosphere Thermosphere System; Geomagnetic Storm
ID Code:54212
Deposited On:11 Aug 2011 11:33
Last Modified:11 Aug 2011 11:33

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