Browsing by Author "Jurua, Edward"

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    Climatology of ionospheric scintillations and TEC trend over the Ugandan region
    (Advances in Space Research, 2014) Amabayo, Emirant Bertillas; Jurua, Edward; Cilliers, Pierre J.; Habarulema, John Bosco
    This study presents results on the investigation of the diurnal, monthly and seasonal variability of Total Electron Content (TEC), phase (rU) and amplitude (S4) scintillation indices over Ugandan (Low latitude) region. Scintillation Network Decision Aid (SCINDA) data was obtained from Makerere (0.34 N, 32.57 E) station, Uganda for two years (2011 and 2012). Data from two dual frequency GPS receivers at Mbarara (0.60 S, 30.74 E) and Entebbe (0.04 N, 32.44 E) was used to study TEC climatology during the same period of scintillation study. The results show that peak TEC values were recorded during the months of October–November, and the lowest values during the months of July–August. The diurnal peak of TEC occurs between 10:00 and 14:00 UT hours. Seasonally, the ascending and descending phases of TEC were observed during the equinoxes (March and September) and solstice (June and December), respectively. The scintillations observed during the study were classified as weak (0.1 S4,rU 0.3) and strong (0.3
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    Statistical analysis of TEC perturbations over a low latitude region during 2009–2013 ascending solar activity phase
    (Advances in Space Research, 2015) Andima, Geoffrey; Jurua, Edward; Amabayo, Emirant Bertillas; Habarulema, John Bosco
    Total Electron Content (TEC) perturbations are manifestations of ionospheric irregularities which induce fluctuations in the amplitude and phase of trans-ionospheric radio signals. TEC data derived from Global Positioning System (GPS) receivers at Mbarara (Geogra. 0.60 N, 30.74 E and Geomag. 10.22 N, 102.36 E) and Entebbe (Geogra. 0.04 N, 32.44 E and Geomag. 9.53 N, 104.10 E) from 2009 to 2013 were used to study TEC perturbations over the low latitude region of Uganda. The results show that the frequency of occurrence of TEC perturbations of >4 TECU increased steadily from 2009 to 2013. TEC perturbations with amplitude <4 TECU occurred at all times. The likelihood of TEC perturbations exceeding 6 TECU was higher during the equinoxes than during the solstices in most of the years. Comparison of TEC perturbations with 10.7 cm solar radio flux (F10.7) data showed a weak positive correlation with this solar proxy. Wavelet analysis performed on the TEC perturbations revealed wave-like oscillations with periods typical of Traveling Ionospheric Disturbances (TID). These wave-like structures (WLS) dominated from 13:00 to 19:00 LT for most of the years analyzed.
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    Tracking the Ionospheric Response to the Solar Eclipse of November 03, 2013
    (International Journal of Atmospheric Sciences, 2014) Amabayo, Emirant Bertillas; Anguma, Simon Katrini; Jurua, Edward
    The ionospheric dynamics is highly influenced by the solar radiation. During a solar eclipse, the moon occults the solar radiation fromreaching the ionosphere, whichmay drastically affect the variability of the ionosphere. The variability of total electron content (TEC) observed by dual frequency Global Positioning System (GPS) receivers has made it possible to study effects of solar eclipse on the ionosphere. Total eclipse occurred on November 03, 2013, and the maximum amplitude was visible at Owiny in northern Uganda. Ionospheric behavior during this eclipse was analysed by using TEC data archived at Mbarara (MBAR),Malindi (MAL2), Eldoret (MOIU), and Kigali University (NURK) International GPS Satellite (IGS) stations. TEC variations of four consecutive days were used to study instantaneous changes of TEC during the eclipse event. The results generally show TEC decrease at the four stations. However, a maximum perturbation amplitude of ≥20 TECU was observed at MAL2 (18:00–20:00UT) which is further south of the equator than the other stations. TEC enhancement and depletion were observed during the totality of the eclipse at MOIU,MBAR, NURK, and MAL2 (13:00–15:00UT). This study found out that the ionospheric TEC over East Africa was modified by wave-like energy and momentum transport and obscuration of the solar disc due to the total solar eclipse.