Endawoke Yizengaw

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The ionospheric storm evolution process was monitored during the 22 September 1999 magnetic storm over the Australian eastern region, through measurements of the ionospheric Total Electron Content (TEC) from seven Global Positioning Systems (GPS) stations. The spatial and temporal variations of the ionosphere were analysed as a time series of TEC maps.(More)
The effects of the 31 March 2001 severe magnetic storm on the Southern Hemisphere ionosphere have been studied using ground-based and satellite measurements. The prime goal of this comprehensive study is to track the ionospheric response from high-to-low latitude to obtain a clear understanding of storm-time ionospheric change. The study uses a combination(More)
[1] We use simultaneous global observations of the mid-latitude trough and the plasmapause to experimentally prove a long-standing conjecture of magnetosphereionosphere couplingnamely the mid-latitude trough and plasmapause are on the same field line. Global Ionospheric Maps (GIM), generated using ground based GPS receivers, are used to detect the globally(More)
The effects of the 15 May 2005 severe geomagnetic storm on the South African ionosphere are studied using ground-based and satellite observations. Ionospheric disturbances have less frequently been investigated over mid-latitude regions. Recently, a number of studies investigated their evolution and generation over these regions. This paper reports on the(More)
[1] We have examined the quiet time equatorial electrodynamics of the ionosphere in the postmidnight sector using satellite, GPS total electron content (TEC) and ionosonde data. ROCSAT-1 vertical drift data are used to estimate the equatorial ionosphere electrodynamics, TOPEX altimeter and GPS TEC are used to obtain the density structure of the ionosphere.(More)
This paper describes the experimental procedures of tomographic imaging techniques that have been developed and used at La Trobe University. Tomographic imaging provides a powerful technique for obtaining images of the ionospheric electron density distribution, and is a relatively new technique which has promising features to supplement the most expensive(More)
[1] Accurate estimation of global vertical distribution of ionospheric and plasmaspheric density as a function of local time, season, and magnetic activity is required to improve the operation of space-based navigation and communication systems. The vertical density distribution, especially at low and equatorial latitudes, is governed by the equatorial(More)
[1] We present a detailed case study of the electrodynamics of a high-latitude trough observed at ~ 12 UT (~1 MLT) on 8 March 2008 using multiple instruments, including incoherent scattering radar (ISR), GPS total electron content (TEC), magnetometers, and auroral imager. The electron density within the trough dropped as much as 80% within 6minutes. This(More)
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