Influence of lightning on electron density variation in the ionosphere using WWLLN lightning data and GPS data

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dc.contributor.advisorInggs, Michael ; Cilliers, Pierreen_ZA
dc.contributor.authorAmin, Mahmud Mohammeden_ZA
dc.date.accessioned2015-07-29T03:42:12Z
dc.date.available2015-07-29T03:42:12Z
dc.date.issued2015en_ZA
dc.descriptionIncludes bibliography.en_ZA
dc.description.abstractIn this study we have demonstrated that a seasonal and diurnal correlation exists between occurrence frequencies of wave-like structures in the form of Traveling Ionospheric Disturbances (TID) in the ionosphere and tropospheric lightning in the mid-latitude region over South Africa. Lightning induced changes in total electron content (TEC) are strongest between September and March, with the more-pronounced effects occurring 12:00 - 22:00 UT, but from April through August there is a low probability of having significant lightning-induced TID occurrence. The strongest oscillations in the total electron content of the ionosphere have dominant periods of range 0.6 to 0.8 and 1.2to 2.5 hours, typical periods for medium scale TIDs and large scale TIDs respectively. Since ionospheric scintillation is caused by irregularities in electron density which act as wave scatterers, it is feasible that lightning-induced TIDs may provide the mechanism for causing the concomitant and co-located changes in ionospheric total electron con-tent that was observed. Both the lightning and the ionospheric irregularity have spatial dependence over South Africa dominating around Bloemfontein. We have also found a strong seasonal and diurnal correlation between occurrence frequencies of the high rate of change of TEC index (ROTI _ 0.8 TECU/min) as a proxy for amplitude scintillationS4 index and lighting stroke rate. The correlation coefficient linking diurnal lightning stroke rate and high ROTI is found to be about 86%. While the seasonal correlation between the monthly average ROTI and average stroke rate is about 70%, the seasonal average ROTI and average stroke rate correlation is found to be about 84%. This there-fore implies that the presence of lightning is a likely cause of the generation of TIDs and subsequent irregularities in the ionosphere.en_ZA
dc.identifier.apacitationAmin, M. M. (2015). <i>Influence of lightning on electron density variation in the ionosphere using WWLLN lightning data and GPS data</i>. (Thesis). University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Electrical Engineering. Retrieved from http://hdl.handle.net/11427/13565en_ZA
dc.identifier.chicagocitationAmin, Mahmud Mohammed. <i>"Influence of lightning on electron density variation in the ionosphere using WWLLN lightning data and GPS data."</i> Thesis., University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Electrical Engineering, 2015. http://hdl.handle.net/11427/13565en_ZA
dc.identifier.citationAmin, M. 2015. Influence of lightning on electron density variation in the ionosphere using WWLLN lightning data and GPS data. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Amin, Mahmud Mohammed AB - In this study we have demonstrated that a seasonal and diurnal correlation exists between occurrence frequencies of wave-like structures in the form of Traveling Ionospheric Disturbances (TID) in the ionosphere and tropospheric lightning in the mid-latitude region over South Africa. Lightning induced changes in total electron content (TEC) are strongest between September and March, with the more-pronounced effects occurring 12:00 - 22:00 UT, but from April through August there is a low probability of having significant lightning-induced TID occurrence. The strongest oscillations in the total electron content of the ionosphere have dominant periods of range 0.6 to 0.8 and 1.2to 2.5 hours, typical periods for medium scale TIDs and large scale TIDs respectively. Since ionospheric scintillation is caused by irregularities in electron density which act as wave scatterers, it is feasible that lightning-induced TIDs may provide the mechanism for causing the concomitant and co-located changes in ionospheric total electron con-tent that was observed. Both the lightning and the ionospheric irregularity have spatial dependence over South Africa dominating around Bloemfontein. We have also found a strong seasonal and diurnal correlation between occurrence frequencies of the high rate of change of TEC index (ROTI _ 0.8 TECU/min) as a proxy for amplitude scintillationS4 index and lighting stroke rate. The correlation coefficient linking diurnal lightning stroke rate and high ROTI is found to be about 86%. While the seasonal correlation between the monthly average ROTI and average stroke rate is about 70%, the seasonal average ROTI and average stroke rate correlation is found to be about 84%. This there-fore implies that the presence of lightning is a likely cause of the generation of TIDs and subsequent irregularities in the ionosphere. DA - 2015 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2015 T1 - Influence of lightning on electron density variation in the ionosphere using WWLLN lightning data and GPS data TI - Influence of lightning on electron density variation in the ionosphere using WWLLN lightning data and GPS data UR - http://hdl.handle.net/11427/13565 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/13565
dc.identifier.vancouvercitationAmin MM. Influence of lightning on electron density variation in the ionosphere using WWLLN lightning data and GPS data. [Thesis]. University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Electrical Engineering, 2015 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/13565en_ZA
dc.language.isoeng
dc.publisher.departmentDepartment of Electrical Engineeringen_ZA
dc.publisher.facultyFaculty of Engineering and the Built Environment
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherElectrical Engineeringen_ZA
dc.titleInfluence of lightning on electron density variation in the ionosphere using WWLLN lightning data and GPS dataen_ZA
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMPhilen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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