Modeling of the seasonal effects of geomagnetic storms in...

Modeling of the seasonal effects of geomagnetic storms in the eastern Asian ionosphere

E. B. Romanova, A. V. Tashchilin, G. A. Zherebtsov, O. M. Pirog, and N. M. Polekh
Institute of Solar Terrestrial Physics, Irkutsk, Russia

V. F. Smirnov, and A. E. Stepanov
Institute of Space Physics and Aeronomy, Yakutsk, Russia

Shi Shi Jiankui, and Wang Xiao
Center for Space Science and Applied Research, Beijing, China

Abstract

[1] The results of studies of ionospheric effects of geomagnetic storms observed in different seasons are presented. A morphological analysis is performed using the data of a network of ionospheric stations located at different latitudes in the longitudinal sector 90^o-130^oE. Significant differences in the ionospheric response to a geomagnetic storm are obtained depending on latitude and season. At middle latitudes the most interesting is that the positive and negative phases of ionospheric disturbance prevail in winter and summer, respectively. To interpret the observed variations in the ionospheric structure, modeling is performed, using a theoretical ionospheric model. The analysis of the processes governing the response of the midlatitude ionosphere to a geomagnetic storm showed a good agreement between the results of modeling and measurements and made it possible to detect the determining role of the neutral composition in the observed variations in ionospheric parameters. At auroral and subauroral stations the variability of the electron concentration during a storm is much better pronounced. According to the results of the analysis of the trajectories of the ionospheric plasma convection, this variability is caused by the joint action of the convection and energetic electron precipitations. The disturbances in the neutral composition in this latitudinal region influence the background electron concentration level.

Received 5 July 2005; revised 28 March 2006; accepted 17 August 2006; published 28 November 2006.

Keywords: Ionospheric storms; Ionosphere-magnetosphere interactions; Numerical simulations.

Index Terms: 2441 Ionosphere: Ionospheric storms; 2447 Ionosphere: Modeling and forecasting; 2407 Ionosphere: Auroral ionosphere.