Investigation of ionospheric response to moderate geomagnetic storms using GPS-TEC measurements in the South American and African sectors during the ascending phase of solar cycle 24.

A. J. DE ABREU; P.R. FAGUNDES; M. GENDE; Y. SAHAI; B. SEGUN; R. DE JESUS; C. BRUNINI; V.G. PILLAT

Addis Ababa

Congreso; AGU Chapman Conference; 2012

Ethiopian Space Science Society

This investigation presents relevant results of the ionospheric F-region response during two moderate geomagnetic storms, one of which is followed by a storm of small intensity, occurred in May 2010 during the ascending phase of solar cycle 24. The first geomagnetic storm the Dst index reached a minimum of -67 nT at 1800 UT on 02 May and the second geomagnetic storm the Dst index reached a minimum of -85 nT at 1400 UT on 29 May. In this study were used 16 GPS stations, covering the South American and African sectors from equatorial region to mid-latitudes. The vertical total electron content (VTEC) is used to investigate the propagation of traveling ionospheric disturbances (TIDs) and positive and negative ionospheric storm phases. The phase fluctuations (TECU/min) are used to investigate the generation of F-region large-scale irregularities (of the order of kilometers). The results obtained will be of large relevance to enlarge the understanding of the electrodynamics and of the physical processes involved on the ionospheric F-region in both sectors during disturbed geomagnetically periods.