Cross Correlation Analysis of Ionospheric Parameters with Symmetric-H
and Auroral Electrojet Indices during Geomagnetic Storms
Abstract
This paper investigates the effects of geomagnetic storms of 25-27
September 2011, 16- 18 March 2013, and 6-8 September 2015 over five mid
latitudes stations (Dourbes, Fairford, Moscow, Rome, and Roquetes) and
performs a cross correlation analysis of ionospheric and solar
parameters during these storms. We observed the highest fluctuations in
ionospheric variables during the main phase of storms. In addition,
there is strong evidence of pre-storm phenomenon occurring at least a
few hours and more than 24 hours prior to the main phase of the
geomagnetic storms. We found that the TEC and foF2 parameters have
strong dependence with latitudes for the events with Sudden Storm
Commencement(SSC) in mid latitude region. Relatively low TEC and foF2
can be observed in Moscow which is at the highest latitude among the
five stations because of a decrease in the n(O)/n(N2) ratio through out
the storm event. However, for the event with gradual storm commencement,
there is no evidence of such dependence. The good correlation of
Symmetric-H and Auroral Electrojet Indices with ionospheric parameters
indicates that the coupling mechanism between magnetosphere and
ionosphere produces intense electric field disturbances in the middle
low latitudes.