Investigation of GNSS ionospheric scintillation occurrence over Bahir Dar during intense geomagnetic storms

TEWACHEW, AGUMAS

dc.contributor.author	TEWACHEW, AGUMAS
dc.date.accessioned	2020-08-25T06:45:42Z
dc.date.available	2020-08-25T06:45:42Z
dc.date.issued	2020-08-24
dc.identifier.uri	http://hdl.handle.net/123456789/11133
dc.description.abstract	Scintillations are the effect of irregular electron density on the propagation of electromagnetic signals through the ionosphere. The scintillating signals change phase unexpectedly and vary rapidlyinamplitude. Thisstudyexaminesthetemporalcharacteristicsofthephaseandamplitude scintillation occurrence during intense geomagnetic storm periods in the year 2015. Scintillation indices(S4 andσφ)dataobtainedfromtwohigh-rateGlobalNavigationSatelliteSystem(GNSS) receiver stations located at Bahir Dar University, Ethiopia was used for this purpose. In the analysis, only GNSS signal measurements at L1, L2C, and L5C frequencies corresponding to an elevation mask of 200 was investigated. Besides the amplitude and phase scintillation, total electron content (TEC), and the rate of TEC index (ROTI) variations also used to investigate the ionospheric irregularity. Results revealed that during the main phase of the storms on 17 March 2015, and on 23 June 2015, scintillation occurrence was suppressed at pre- and post-midnight hours. On the other hand, the level of scintillation was triggered during the main phase storm period of October 7 and December 20, 2015, at the pre-midnight hours. Comparative results between scintillation occurrence during the storm and quiet time showed that scintillation was more pronounced during quiet periods. It is also observed from the experimental results that the strong scintillations occur during March equinox and December solstice, and lowest during June solstice. Keywords: Ionospheric scintillation, Phase and amplitude scintillations, Geomagnetic storm	en_US
dc.language.iso	en_US	en_US
dc.subject	PHYSICS	en_US
dc.title	Investigation of GNSS ionospheric scintillation occurrence over Bahir Dar during intense geomagnetic storms	en_US
dc.type	Thesis	en_US